A-stage or “A state” is a description of the degree of crosslinking of resin systems. A denotes “non-cross-linked, fluid.” This is particularly important for printed circuit boards when manufacturing multilayer printed circuit boards when using prepregs. See also B-Stage and C-Stage.

A state is the state of resins in which they are still liquid, see A-Stage.

Blow-off generally refers to a hot air tinning (HAL) process in PCB manufacturing. After dipping the circuit board in hot tin, the excess tin is blown / blown off with high air pressure.

Absolute identifies the reference value of the coordinates for circuit board data. With an absolute reference system, all values ​​are related to a point from their position. The opposite of this is the relative frame of reference, in which each position results from the difference to the previously mentioned.

Chemical absorption describes the process of taking up or “releasing” an atom, molecule or ion in another phase. This is not an accumulation on the surface

ACA stands for “Anisotropic Conducting Adhesive” and describes an adhesive that is conductive in the Z-axis. It is used in flex-to-board applications and can make soldering connections unnecessary. Since this adhesive is not conductive in the X and Y directions, this adhesive film can be applied over the entire surface of the connector (for example on a flexible circuit board) and glued to the counterpart (for example rigid circuit board).

Adapters are used here for electrical testing. They usually contact the points with springy needles which are to be checked electrically. The needles are then connected to the test device

The adapter test is the opposite of the finger test and describes the process of electrical testing of bare and populated printed circuit boards using an adapter -> the advantage is that the test of the printed circuit boards is much faster here than with a finger tester (flying probe), which only bare circuit boards can be used. However, the adapter construction is complex and expensive, which is why this is only worthwhile for larger series of quantities.

ADD stands for “Advanced Dielectric Division” and is a base material division of the company Taconic, which is mainly used for high-frequency printed circuit boards.

In chemistry, activation is the treatment of surfaces (e.g. cleaning) for further chemical treatment.

ALIVH stands for “Any Layer Internal Via Hole” and is an electronic connection between layers that are made using conductive pastes. These conductive pastes are usually doctored onto the printed circuit boards using a screen printing process. The advantage lies in the high speed and in the selective selection of the holes to be contacted, in contrast to a full-surface through connection method.

Alkaline solutions (bases/bases) are usually aqueous solutions of alkali hydroxides (e.g. sodium hydroxide solution) or potassium hydroxide (potassium hydroxide solution). The term is also used for every solution of bases. Alkaline solutions can also be non-aqueous solutions. The pH of the bases is greater than 7 (up to 14).

In alkaline etching, metals are removed with an etching solution based on a base (e.g. ammonia sulfate). In contrast to acidic etching with acids (ferric chloride)

All Digits Present classifies the display of drill files in text format. Depending on the setting in the CAD program, it is possible to suppress zeros at the beginning or at the end of the respective coordinates. This originated in the times when every bit of storage space was valuable. The display with the setting All Digits Present would not suppress zeros at the beginning or at the end so that all coordinates are displayed in their entire length: X0030Y0430.

are 2 or multi-layer printed circuit boards, which have aluminum layers inside. It should be clearly distinguished from aluminum carrier circuit boards, where aluminum is only on one side and not inside. Aluminum core circuit boards offer the possibility of integrating heat sinks into the circuit board. Through-plating is possible by pre-drilling and isolating the aluminum carrier.

Aluminum carrier boards are single or multi-layer printed circuit boards that have an aluminum layer attached to an outer layer. There is a clear distinction between aluminum core circuit boards with aluminum inside. Aluminum carrier circuit boards offer the possibility of gluing heat sinks directly to the circuit board.

Aluminum wire bonding or aluminum wire bonding is an ultrasound bonding process, which produces thin wires (bonding wire) for connecting the printed circuit board with the chips on it. For this, certain surfaces on the circuit board are necessary, or better or less suitable. Thin-layer gold plating from 0.01 to 0.12 µm gold over 2.5 to 4 µm nickel is common. Due to the lower requirements for gold thickness and the use of aluminum as a connecting element, this method is generally cheaper than gold wire bonding.

Aluminum core is an aluminum layer integrated in multilayer printed circuit boards for heat dissipation

Aluminum carrier is an aluminum layer applied on one side to single or multi-layer printed circuit boards. Contrary to the aluminum core, this position is visible from the outside and has no through-bores.

Ambient stands for “environment” and describes the component environment for the definition of Rth (see there)

Ammonia is used in the production of printed circuit boards for the alkaline etching of printed circuit boards.

Ampere [A], according to André Marie Ampère, is the SI base unit of electric current with the formula symbol I. Exactly 1 ampere flows through a 1-ohm resistor when a voltage of 1 volt is applied

Pressure of the doctor blade on the screen or contact pressure of the laminator rollers when applying foils

An anion is a negatively charged ion. Since negatively charged ions migrate to the anode (the positive pole) during electrolysis, the name Anion was chosen for them. Anions arise from atoms or molecules by electron uptake. S. cations.

Acceptance quality characteristic, AQL for short, is a term from quality management. It describes statistical sampling procedures according to which different requirements can be checked in order to accept or reject lots without having to carry out a 100% check.

Anode is the positive electrode, here for the electrolytic deposition of copper in electroplating as a copper supplier

In the electroplating process, the anode bag identifies the bag drawn over the electrodes in order to avoid mechanical contamination of the bath with anode sludge.

AOI is the Automatic Optical Inspection and characterizes an optical inspection of the PCB structures by a machine. For this purpose, the data generated from the CAD are read into the AOI machine, which then moves the circuit board with cameras and compares it with the target data. Deviations that go beyond a previously defined tolerance are displayed on a monitor.

Aperture is the English term for “aperture” in printed circuit board production. So-called “aperture files” or “aperture tables” are aperture tables in which the shapes used in the layout and the largest are assigned via codes. The origin of these “apertures” lies in the use of “tools” which corresponded to the shape and size actually to be reproduced. As a result, the shapes were much more restricted than today, where laser plotters can reproduce any shape in great detail.

AQL, see acceptance quality characteristic

Aqua demi is the name for demineralized (undistilled) water. Here the minerals (salts) are extracted from the water (see osmosis)

Aqua dest is the name for distilled water. This water is purer than aqua demi. (see distillation)

Special plastic fabric. Aramid is produced as a film, but mostly as a fiber. Aramid fibers are golden yellow organic synthetic fibers

Arc interpretation characterizes different approaches of the CAD programs to represent arcs.

In PCB manufacturing, archive refers to the data archive on the one hand, in which the customer and production data for manufacturing are stored. There are also film archives so that existing films can be used for repeat orders of printed circuit boards with individual production.

Arcs mark arcs in CAD programs.

Arlon is a manufacturer of flexible substrates and coatings, some of which are used in the manufacture of printed circuit boards. For more information

Artwork often describes the films that are required to manufacture printed circuit boards.

ASCII stands for “American Standard Code for Information Interchange” and marks the readable character set in files. In the circuit board industry, ASCII is important in the representation of layout information in files. Older formats such as Standard Gerber and Extended Gerber use ASCII, which is why you can open and view the files with a text editor. However, other, newer formats are compiled and can therefore no longer be read with simple text editors.

ASIC is an “application-specific IC” which has been individually programmed for an application. By using ASICs, assemblies can often be downsized, since an individually created IC can often combine functions of otherwise several components. However, programming the ASICs requires a certain amount of know-how.

Aspect ratio is the relationship between hole depth and hole width. The aspect ratio is important because as the aspect ratio increases (e.g. a thinning hole with the same board thickness), the difficulty of perfect through-contact increases.

Asymmetrical PCB structure is particularly common in multilayers. The asymmetry here refers to the displacement of the inner layers away from the central axis. This makes it easier to produce desired impedances for some applications in high-frequency technology. However, the production of asymmetrical multilayer printed circuit boards harbors dangers, since the different copper distribution in the fabric can lead to twisting and warping of the boards.

Au is the chemical symbol for gold (aurum). Gold is particularly important in the manufacture of printed circuit boards as surface refinement with various properties and functions.

AutoCad is a widely used software for creating technical drawings. It is often used to create the benefit drawings of the circuit boards and to illustrate the outer contour and the relevant tolerances.

Autorouter is a function of layout software that automatically takes over the actual structuring of the circuit board from a circuit diagram. While the circuit diagram of the circuit board represents a purely schematic representation of the connections, the autorouter uses it to create the actual circuit diagram, which must be applied to the circuit boards in order to correspond to the circuit diagram.

AVT is an abbreviation for “assembly and connection technology”, which characterizes the assembly and soldering of printed circuit boards.

Assembly is a process that follows the manufacture of printed circuit boards. The circuit board forms the basis for the assembly in the form of support for the components and the connecting element thereof. Depending on the assembly method, different requirements can be placed on the production of printed circuit boards.

Assembly printing refers to the lacquer applied to identify positions on the printed circuit boards. It is therefore often called position printing or marking printing. This is usually white, whereby yellowish colors are also used as standard and are very well recognizable on the green standard solder mask. The assembly print is applied either with a screen printing process or by full-area printing with subsequent exposure and development of the color that is not required. This does not require a sieve, so it is also more suitable for small quantities. Recently also with a special printer, similar to an inkjet printer. It can also be used to inexpensively print individual items since not even a film is required.

Aperture is a term used in plotting technology or CAD and describes the shape and size of objects that will later be applied to the circuit board. The term “aperture” is of historical origin since old plotters had a corresponding magazine on apertures, which were used accordingly for the different objects. Special shapes and deviating sizes were therefore only possible under increased load. Today the term “aperture” still exists, although no real apertures are used. Today’s laser plotters can expose any shape directly to the film without an upstream aperture that gives shape.

Aperture tables are tables in which the apertures used are listed. Aperture tables are only common for standard Gerber data, where a date contains the corresponding positions (coordinates) with the assignment of an aperture (D code). The actual shape and size are stored in the aperture table, which can be referenced and assigned using the D codes. Aperture tables are no longer necessary with Extended Gerber since the aperture information with the coordinates are stored in a file.


B-Stage describes the degree of cross-linking of resin systems, whereby the B-state means “partially cross-linked: solid, but dissolving or re-liquefaction possible”. See also A-Stage, C-stage, Prepreg

B state is the state of resins in which they can still be caused to flow by temperature.

B2B stands for business-to-business and describes business between two commercial companies. All PCB manufacturers are commonly found in B2B.

B2C stands for business-to-consumer and describes business between a trade and a private individual. Some PCB manufacturers do not offer B2C as they only want to do business with other traders.

Ball grid array is also called BGA. They are a newer form of components in which the connection to the circuit board is not made via conventional pins but via spherical connections. The main advantage here is that it saves space since considerably more connections can be made by placing them under the module instead of on its edges. However, this poses further challenges in later assembly, particularly in the control of the solder joints. Under the BGA itself, this is only possible by X-ray, since the connections are covered up for the eye.

Barco is a company in the field of inspection systems and software for the PCB industry.

Bare board refers to bare printed circuit boards without components.

Base Film is the name for the base material of flexible printed circuit boards. Due to the low thickness of the material, there is often talk of a “film”.

Base copper describes the copper layer on the raw circuit board base material in the delivery state. This forms the starting point for later copper structures. It is common, for example, to start with standard 35um with a base copper of 18um. The missing 17um are built up by through-plating and amplification. Base copper thicknesses of 18um, 35um, and 50um are common for rigid circuit boards. For thick copper boards, even higher base copper is sometimes used. For flexible printed circuit boards, 12um, 18um, and 35um are common.

The base material is the raw material delivered to the PCB manufacturer. The base material is often delivered as so-called “tableware” and must be cut accordingly before the start of production. There are various base materials with different thicknesses, coatings, electrical and physical properties for a number of requirements for the printed circuit boards.

BE stands for “component” and can mean a wide variety of groups, such as ICs (chips), microcontrollers, coils, resistors, capacitors. In general, the board itself is not referred to as a component (BE) because it acts as a carrier and connecting element.

Bergquist offers a range of very high-quality materials for aluminum carrier or aluminum core circuit boards. The performance in the area of ​​heat dissipation is usually better than with self-pressed standard materials. The reason for this is a special insulation material between the aluminum and the copper. With conventional epoxy resin, this insulation layer is an obstacle to good heat dissipation. Bergquist’s insulation material is considerably better here, depending on the type.

In which the PCB edges are flattened. This is mainly used for plug contacts, such as computer plug-in cards, to make it easier to insert the board. The protection of surrounding components from sharp edges during installation can also be a reason for flattening the edges.

BG is the abbreviation for “assembly” and describes a fully assembled and assembled printed circuit board with components (BEs).

Bending radius is a term that is important for flexible printed circuit boards that are exposed to high bending stress. The bending radius depends on the material composition (copper, adhesive, base material) and the thickness of the flexible printed circuit board.

Bilayer rarely used term for two-layer printed circuit boards (Bi = two). “Double-sided” or “two-ply” or “two-ply” are used more frequently than the term bilayer.

Billing is delivered orders in contrast to bookings, which means orders.

Bimsen is a process of surface roughening during circuit board manufacture. While corresponding rollers rub over the boards during “brushing”, pumice powder is mixed with water during pumice and blasted onto the printed circuit boards with high pressure. The pumice flour particles in the water create the corresponding friction on the copper to roughen it.

Bitmap is an image format that is rarely supplied as a data template for circuit board manufacture. This is often used when there is no layout data available for the circuit board. With a little extra effort, it is possible to generate corresponding Gerber data from bitmap files in the CAM and to produce a printed circuit board.

Black Pad refers to an appearance when chemical gold is applied as a printed circuit board surface. Here it can happen that some pads turn black

Blackhole is via a process that uses carbon. In the blackhole process, these carbon particles are flushed into the holes to be plated through, so that the carbon creates a conductive connection for subsequent copper deposition in the hole. The blackhole process is considerably faster than a chemical copper deposition.

Blistering is an undesirable effect with multilayer printed circuit boards. Contamination of the prepreg or low pressing temperatures can lead to air pockets in the circuit board material. These air pockets become problematic in the subsequent soldering processes because the air expands under heat. These bubbles are visible in the material and on the one hand, can lead to an uneven surface and thus make it difficult to assemble the circuit board, and on the other hand, the bubbles can be too close to copper connections and tear them apart.

Blind is a colloquial abbreviation for “Blind Via” or “Blind Hole”

Blind vias are also called “blind holes” and indicate holes that are only drilled from an outer layer in the multilayer core. Blind holes do not go through the entire circuit board and are therefore not visible from one side. Depending on the drilling diameter and depth (see aspect ratio), blind hole technology brings with it various challenges but is now considered to be largely mastered.

Bordicht describes the number of holes in relation to the area. For larger series, the drilling density has a significant influence on the price, because the increasing drilling density increases the machine time and thus the costs. In prototypes, this is often left out of consideration or included at a flat rate.

BOM stands for “Bill Of Materials” and denotes the component list for the PCB assembly in English.

Bond gold refers to a surface on printed circuit boards that makes bonding easier. This is usually a gold surface. Depending on the bonding process, this can be chosen thicker or thinner. Bond gold has a number of other advantages for printed circuit boards, for example, the surface is more durable and is often easier to solder than tin surfaces.

Bonding refers to a method of making connections between bonding ICs and the circuit board underneath. A distinction is generally made between ultrasonic bonding and thermal bonding. The two processes have different requirements for the gold surface on the circuit board. Therefore, you should explicitly point out to the manufacturer for which bonding the boards are needed.

Book-to-bill is the ratio of incoming orders in a month to the invoiced orders. A book-to-bill of greater than 1 thus indicates an increase in order intake compared to the previous month. A book-to-bill of less than 1 means that fewer printed circuit boards will be produced in the month in question than before, so incoming orders will shrink. Statistics on the industry-wide book-to-bill ratio of the German circuit board manufacturers are regularly compiled and published by the FED.

Bottom denotes the “underside” of lyre boards. It is often called the solder side.

Brown oxide is a process for the surface roughening of PCB inner layers in the production of multilayers (also called “black oxide”). By applying brown oxide, the prepregs adhere better when pressing the multilayer.

brd files or board files mainly describe layout files that were created with the “Eagle” software from CADSoft. The layout files have the extension “* .brd”.

Breakout describes holes that break out of the intended pad, so they are not centered on it. Depending on the strength of the breakout and the direction, these are permitted or not according to IPC and PERFAG.

Bromides are flame retardants found in printed circuit board base materials and plastics. Since these were also classified as toxic, bromides are no longer used in the production of printed circuit board base materials. The RoHS regulation prohibited the use of bromides as flame retardants.

BT material is a halogen-free high-temperature material developed by Mitsubishi with the main components bismaleimide (B) and triazine resin (T). It is mainly used in the manufacture of IC packages.

Bump denotes galvanically raised bumps on pads to simplify contacting of the circuit board.

“buried holes” and denote holes within a multilayer that are not visible from the outside. Buried vias only contact inner layers and are drilled, plated through and plugged (closed) before the multilayer is pressed. The sealing takes place, among other things, to avoid air pockets and unevenness in the finished multilayer.

Burn-in is a procedure to avoid early failures of delivered devices. Here, the device is operated for several hours under alternating loads and temperatures in order to detect hidden manufacturing defects (mostly in the case of semiconductors) at an early stage.

Brushing is a method of roughening the surface. The circuit boards are pushed into a continuous system in which a preset height between two brush rollers is required. The pressure control controls how much the brushes should press on the circuit boards and thus regulates the roughness depth

B²IT or BIT stands for “Bump Interconnect Technology” and describes a special connection technique in which pads with copper are built up to create an increase. This increase in copper allows better contacting of other connecting elements and can be found in particular in printed circuit boards for flip-chip applications in which the components are only placed on and fastened by an adhesive instead of being soldered or bonded.

Batch treatment describes a process in which, in contrast to continuous treatment, only a certain amount is completely treated at a time.

Breakdown voltage is the voltage at which a discharge takes place between two potentials via an insulator in between. This breakdown voltage is important for printed circuit boards when the insulation layer has to be adapted accordingly. This is done either by increasing the distance between the corresponding layers or by choosing another base material with higher dielectric strength.


Cover foil is a kind of solder stop for flexible printed circuit boards. Since paints have only a limited flexural strength, cover foils are stuck on here to protect the copper structures. The advantage is that a very high bending load is possible. The disadvantage is that these foils have to be cut or drilled and cannot be developed like photosensitive solder resist. The result is that only larger structures in a rectangular shape are possible, or small exemptions are always round (drilled). Cover foil is therefore only suitable to a limited extent for flexible circuit boards with fine SMD areas.

Chamfering denotes the angling of PCB contours. This is mainly required for connectors to ensure that the circuit board can be inserted more easily into the socket.

On-demand orders are a term from the merchandise management and are used in particular for large series of printed circuit boards. Here larger quantities are ordered for an agreed period, whereby this quantity is then delivered (called off) in lot sizes. The advantages here are in particular the lower prices due to higher quantities and the often shorter delivery times for follow-up lots. Framework contracts are disadvantageous if there are changes in the design or the contractually agreed quantities cannot be accepted within the set period.

Curing oven is important for drying paints, mainly solder resist and component printing. The paints dry through the heat and become hard.

Curing temperature is the temperature at which coatings on printed circuit boards become hard. Depending on the paint and curing process, these temperatures are higher or lower. The duration of curing also plays a crucial role.

Component side is the side of the circuit board that is populated with components. It is often referred to as a top layer or component layer. The designation of the upper layer as the component layer has a historical background since previously printed circuit boards were only fitted on one side, while the underside (conductor side) was only used to guide the conductor tracks. Today, many printed circuit boards are populated on both sides, which makes the designation “component side” misleading.

Coating describes the application of surface refinements to the board, for example, chemical gold, chemical tin or HAL lead-free.

C-Stage also called “C-state” is a state of resin-based plastics, mainly FR4 and prepregs for multilayer printed circuit boards. The C state indicates the complete solidification/hardening of the resin. See also A state and B state.

CAD stands for “Computer-Aided Design” and describes in circuit board manufacture the layout that preceded the manufacture of the circuit boards. Strictly speaking, there is no longer any “design” in PCB manufacturing. All adaptations and data changes at the PCB manufacturer fall into the CAM category since this is only about the preparation (M for “Manufacturing”) and there are no more design changes in the PCB layout.

CAF is the abbreviation for “Conductive Anodic Filament” and describes the phenomenon of electromechanical migration of metallically charged salts through a non-conductive carrier.

CAF resistance describes the resistance of an insulating material (for example FR4) to prevent CAF, the electromechanical migration of metalized salts.

CAM stands for “Computer-Aided Manufacturing” and describes the steps of data processing after completion of the design (CAD). The reason is that various parameters in the design have to be changed so that the printed circuit board corresponds as closely as possible to the design. Programs must also be created for milling machines and e-testers that conventional layout software for the design of printed circuit boards does not include. For this reason, completely different software is usually used for CAM processing in the circuit board production than for the previous CAD steps of the layout creation.

CAM350 is a CAM software from Downstream Technologies that is used to edit circuit board layouts on the part of the circuit board manufacturer.

CAMMaster is a CAM software from Pentalogix LLC that is used to edit circuit board layouts on the part of the circuit board manufacturer.

CAMTEK is a company that produces machines for the optical inspection of printed circuit boards (AOI for short) for the printed circuit board industry.

CAR is the short form of “Corrective Action Record” and comes from the quality management. CARs are as important in the PCB industry as in any manufacturing company. They serve to document a precise analysis of errors, problems, and defects that have arisen. Based on the analysis, “corrective measures” are developed in a CAR, which should largely exclude the errors that have arisen for the future. Companies that take quality management seriously and see themselves as a learning organization cannot avoid CARs. A modification of the CAR is the so-called 8D report.

Carbon is used in two different places in PCB production. First – and less obvious because it is part of a manufacturing process – in the via a process called “black hole”. Second – and then usually explicitly requested, since it is often essential for the use of the printed circuit board – as “carbon print” or “carbon print”. In addition to the conductive properties, the high hardness of the material is used, which is why it is used as a coating for pushbuttons on the circuit board.

Carbon conductive varnish or “carbon varnish, carbon varnish” is made of graphite (carbon) and is mostly used to harden tip contacts and scrapers on printed circuit boards. In addition to the mechanical use of the properties of graphite, carbon conductive varnish is also used for integrated resistors and potentiometers.

CBGA is the abbreviation for “Ceramic BGA” and denotes a ball grid array component that is made of ceramic.

CE is a label that stands for “Conformité Europénne” and describes compliance with the guidelines applicable in Europe. It is not necessary to affix the CE marking for the circuit board itself since the guidelines go far beyond the function or nature of the circuit boards themselves. To what extent completed assemblies comply with the CE directive is not within the sphere of influence of the printed circuit board manufacturer.

CEM 1 material is a circuit board base material based on hard paper. It has a reputation for being relatively cheap and easy to punch, which is why it is still in demand for price-sensitive products. However, since FR4 has largely established itself as the standard and is now used in much higher quantities than CEM 1, the price advantage is reduced enormously. Many manufacturers therefore hardly buy any CEM 1 material.

Copper-clad epoxy resin core covered with glass fabric impregnated with epoxy resin. The mechanical stability of this material is slightly lower than that of FR 4, the electrical values ​​meet the data prescribed for FR-4

Chemical gold is a printed circuit board surface, which is also called “chemical NiAu”. Ni stands for the component nickel, which is applied between copper and gold. Chemical gold has various advantages for printed circuit boards: it is bondable, it is very planar, it is long-lasting and easy to solder. The relatively high process costs are disadvantageous.

Chemical silver is a printed circuit board surface, which is also called “chemical Ag”. Contrary to chemical gold, this is only partially bondable and comparatively difficult to store. It has the advantage of the planar surface in common with chemical gold. It is less common in Europe than, for example, the United States. The process is considered to be relatively cheap but has not become established in Asia and Europe.

Chemical tin is a printed circuit board surface, which is also called “chemical Sn”. Chemical tin is planar and easily solderable. It has disadvantages in high sensitivity and lower shelf life. It is a relatively cheap process for PCB manufacturing.

CIC stands for “copper-Invar-copper” and describes a basic material structure with an Invar instead of FR4. Invar is an iron-nickel alloy with 36% nickel (FeNi36). Invar has an extremely small and sometimes even negative coefficient of thermal expansion (CTE) and is therefore well suited for high-temperature printed circuit boards

Circle is an objective tool for creating circular structures in circuit board design (layout creation).

Circuit Board is the short form of Printed Circuit Board (PCB) and simply stands for printed circuit board or board.

CNC stands for “Computerized Numeric Control” and means that the drilling, milling and scoring machines used today receive numerical data with the corresponding coordinates. What sounds self-evident today was still a novelty in the 1980s, where holes were often still made manually based on the film.

Coating stands for “layer” or “color layer” and generally refers to the solder resist on printed circuit boards. Other “coatings” are often desired, mostly in the form of special protective lacquers.

COD stands for “Cash on Delivery” and is part of the payment terms. It almost corresponds to the surname procedure from the time of payment, with the difference that the payment does not necessarily have to be made to the postman, but the time of delivery merely describes the due date of the invoice. Almost all payment terms can be found in the PCB industry. Although COD is rather uncommon in business, this payment term can be part of the agreement, for example, to reduce the price of the boards for it.

Copper, the chemical symbol is Cu. Copper is a very important component of printed circuit boards. Almost all conductive connections are made from copper.

Copper Bump is an additional copper survey on the copper for better contacting. Here, a laminate is again applied to the finished structured circuit board, which frees up the areas to be removed and covers the rest. A chemical survey is built upon the exposed areas by chemical copper deposition.

Counter Sink is “lowering”. Countersink holes are counterbores. In this case, the circuit board is not drilled completely with a drilling diameter but is drilled on one side only with a larger drill or countersink to a certain depth. So screws can be used for fastening, the heads of which are flush with the circuit board.

Crimping is a mechanical connection technology that is used for flexible printed circuit boards and, above all, for cable connections to connectors.

Cross-hatching refers to hatching in printed circuit board ground areas. The difficulty in the production of printed circuit boards can arise here when the crosshatch is not considered that the same structural limits apply as for printed conductors.

Crossed vias, or “crossed holes” are buried holes that go over different layers. These structures can only be implemented sequentially, which is why cross vias can be found in SBU technology (sequential build-up). Since this is only necessary for very complex and high-layer multilayers, many printed circuit board manufacturers do not offer crossed holes.

CSP is the abbreviation for “Chip Size Package” and describes a component whose size has hardly increased due to the housing.

CTE stands for “Coefficient of Thermal Expansion” and means “thermal expansion coefficient” is given in ppm / K. In addition to the most insignificant thermal expansion of printed circuit boards in use, the CTE is extremely important in the production of multilayers. Since copper and epoxy have very different CTE values, the layers expand differently during hot pressing. If these layers stick together under heat, tensions can occur during the subsequent cooling process, which is manifested in the form of twists and warps. In order to keep these tensions as low as possible or to distribute them evenly, the copper in the inner layers must be distributed as evenly as possible. If one inner layer is a ground plane and the other has only a few signal layers with comparatively low copper, this promotes bent printed circuit boards. The PCB manufacturer has little influence on this since it is physical conditions that must be taken into account in the layout. The PCB manufacturer can and should only point this out when ordering layouts with the very different copper distribution.

The CTI value (Comparative Tracking Index) denotes the tracking resistance, i.e. the insulation resistance of the surface (creepage distance) of non-conductors, due to moisture and contamination. This defines the maximum leakage current that is allowed to flow under certain test conditions.

Cu-Sn / Pb (copper lead-tin) is a historic surface refinement for printed circuit boards that were melted (also called “remelting”). The process is very similar to wave soldering and therefore slow. It was replaced by the faster hot air leveling (HAL), whereby the lead-tin application can also be thinner.

CVD stands for “Chemical Vapor Deposition”. It is a coating process for microelectronic components.

Continuity test here denotes a part of the electrical test of printed circuit boards.

Continuous plant is a machine in the production of printed circuit boards, whereby the boards run continuously through the machine (mostly horizontally). It is the opposite of diving systems (vertical), in which the circuit boards are immersed vertically. Typical continuous systems in the production of printed circuit boards are brushing machines, cascade rinsing, resist strippers and etching machines. There are also some continuous systems for through-plating and printed circuit boards.

Climbers mean plated-through holes, the task of which is to connect the layers to one another. They are also called VIA today. Climbers do not include the plated-through holes in which components are later soldered.


In PCB manufacturing, deposition usually means the application of metal to the PCB. A distinction is made here between chemical deposition and galvanic or electrolytic deposition. The former is mostly used over the entire surface for copper in the through-plating process, the latter when re-amplifying the circuit boards. In addition to copper deposition, there are also deposition processes on the various end surfaces, mainly chemical tin (Sn) and chemical nickel-gold (NiAu).

Settling is a concept of the deposition process. Settling describes a separation of the heavier elements from the lighter ones by floating or sinking.

In printed circuit boards, spacing usually indicates the spacing between conductor tracks or any copper structures. In the case of special multilayer structures for, for example, high-frequency applications, distances between the layers are also relevant. Most of the time, the context and the values ​​quickly reveal the intervals.

The drilling pattern check is a check for completeness of all required holes in the circuit board.

The drill cover layer is usually a layer made of aluminum, which is placed over the circuit board to be drilled. This drill cover layer made of thin aluminum ensures better drill guidance since the drill is thereby fixed and can no longer run so easily when drilling packages (several printed circuit boards one above the other). Aluminum cover layers also have a cooling and lubricating effect

Drilling is one of the first processes in the manufacture of (1- and 2-layer) printed circuit boards. Drilling allows later connections from the layers, as well as the insertion of components. In the case of multilayer printed circuit boards, the drilling process is usually carried out afterward, since the inner layers must first be structured and pressed before they can then be drilled.

Drill is available in PCB manufacturing from 0.10mm to over 6mm. Due to limitations of the recording magazines of the drilling machines, high acquisition costs with little use (mainly affects larger drilling diameters), as far as the risk of the drill breaking (mainly affects thinner drilling diameters), the actual availability of drills is often between 0.20 and 4 mm. Thinner bores are not a big challenge when it comes to creating the hole, but through-plating is difficult, which is why many manufacturers do not offer bores below 0.20mm. Holes over 4mm are often milled. This has an advantage in terms of hole quality since large drills usually produce more burr than a milling cutter.

Drill break control is required to ensure that all holes have been carried out in accordance with the drilling program and that a drill has not broken off in the middle of the drilling process and corresponding holes are missing. This drill break control is often done on two levels. On the one hand, modern drilling machines use the contact between the drill and the drill cover layer to check whether the drill is still there in full length with each drilling stroke. On the other hand, drilling films are often plotted, which are placed after the drilling process for visual control over the drilled blanks. If holes are missing here, this can be seen quickly. Furthermore, control holes can always be made as to the last hole with any diameter at the edge of the panel.

Drill magazine describes the storage of drill bits on drilling machines. These magazines are very generous today, while old drilling machines often still required manual loading of the drill according to the required diameter.

Drill number describes one of the first marks in the circuit board manufacturer to be able to assign the order. Since there is no structuring of the printed circuit board at the start of production, a corresponding batch or order number is drilled into the production blanks. Identification is therefore possible even without copper structures.

Drilling cardboard is pressed cardboard underneath for drilling, which protects the drilling table. Since even the lowest PCB has to be completely penetrated by the drill, a spacer to the machine table is required. This cardboard is usually 2-3mm thick and is often used several times.

Drilling spindle is the part of the drilling machine that performs both the rotary movement of the drill and the strokes in the circuit board. There are drilling machines with different numbers of spindles. While “single-spindle machines” are useful for prototypes and small series, “multi-spindle machines” with up to 6 spindles are used in series production. The advantage of multi-spindle machines is that they can drill larger quantities at the same time side by side without the need for repeated manual assembly work. The disadvantage is that spindles have to be switched off if they are underutilized, but they still move in the drilling machine. It is not possible to drill different drilling programs on different spindles at the same time.

Drill table is the area on which the circuit boards are positioned for drilling.

The drill pad is the opposite of the drill cover sheet, see “Drilled cardboard”.

Drilling allowance describes increasing the drilling diameter delivered in the PCB layout. These drilling allowances must be made because the diameters shown in the layout are final diameters. However, since both copper and a surface finish are added to plated-through holes, making the hole narrower, this amount must be added accordingly beforehand. Depending on the manufacturer, copper thickness, plated-through hole or non-plated-through hole and surface finish, drilling allowances from 0.05mm to 0.25mm are common.

Distance is used in printed circuit boards to designate the structures or distances between copper structures. In layout checks, for example, there are “clearance errors” if the minimum copper spacing on the circuit board is not reached.

D-Code is the name for aperture values ​​at Gerber. D codes consist of a D value from 10 upwards (e.g. D10), a character for the form (e.g. R for Rectangle) and at least one value (e.g. 0.50). If there is a second value for this shape (e.g. 1.0), the 0.5 square becomes a rectangle (1.0×0.5). The units in the form of mm, mil, inch, etc. are usually not contained directly in the D code, but in the header area of ​​the Gerber data. This D code defines what the shape should look like. Information on the coordinates in the Gerber file then only refer to D10 without giving the size and shape information again.

DCA stands for “Direct Chip Attach” and describes the assembly of bare silicon chips directly on the circuit board.

Design describes the design of circuit boards or the appearance of the circuit board. The design of the circuit board has a significant impact on the function and cost of the assembly. In more complex cases (e.g. in HF technology) it is advisable to cooperate with the printed circuit board manufacturer before starting the design in order to check costs, feasibility and material availability.

Design For Manufacturing (DFM for short) is the underlying manufacturing rules that must be observed when manufacturing printed circuit boards. You can use the Design Rules Check (DRC) to check whether the design for manufacturing has been observed.

Design Rules Check (DRC for short) is a process that checks the layout data of the circuit board for manufacturing rules. Depending on the possibilities and manufacturing complexity (price), manufacturers require certain structures in the copper, minimum drilling diameters, distances to outer contours, solder mask exemptions, etc. These are checked for compliance with the Design Rules Check. Nowadays, modern CAM software offers automated control functions for a number of tests in the PCB layout.

Removal of molten glass fiber drilling residues by chemical treatment with super-manganese potassium (potassium permanganate KMnO4) or by plasma etching back.

Distillation is a thermal separation process to separate a liquid mixture with different substances that are soluble with each other. The individual substances separate due to the different boiling points of the liquids involved.

Decimal point is a numerical component that is important in the manufacture of printed circuit boards, particularly with regard to data declaration. There are various file formats that do not have decimal points in the coordinates, but instead, use a number to define where the decimal point is to be understood. This poses risks and difficulties if this definition (e.g. 2.4 for 2 digits before the decimal point and 4 behind it) does not exist. In addition, there are various format compressions that precede or suppress pending zeros and can thus make the interpretation of data more difficult. If a format allows the insertion of decimal points, this is always advisable.

DGA stands for “Die Grid Array” and describes a component with a grid of bumps directly on the chip, so that circuit boards can be contacted directly

Diazo film is a very stable yellowish film for the exposure of printed circuit boards. The exposed areas change color from light yellow to dark brown. These areas are then no longer penetrable for the UV parts of the imagesetter. For the visible yellow light and thus for the operator, the film remains transparent and can be easily adjusted. Diazo films cannot be plotted directly, but are created as a print of silver films that are less scratch-resistant. The production of diazo films is often dispensed with in prototype production today since the silver films are completely sufficient for a few exposure processes. However, diazo films are essential for the archiving of films and series production.

Dieken is a company (Dieken GmbH) that specializes in the programming and installation of process software for the PCB industry. This is not CAD / CAM software, but the database and production controls (PPS).

A dielectric (plural: dielectrics) is any weakly electrically or non-conductive, a non-metallic substance whose charge carriers are generally not freely movable. A dielectric can be either a gas, a liquid or a solid. Dielectrics are usually referred to when these materials are exposed to electrical or electromagnetic fields. Dielectrics are typically non-magnetic. Here it is the basic material.

Diffusion is a physical process that leads to an even distribution of particles and thus to the complete mixing of two substances. It is based on the thermal movement of particles. These can be atoms, molecules or charge carriers. Mostly surface diffusion into the copper of the printed circuit board.

Diffusion barrier is a nickel layer in surface processes to avoid e.g. Gold diffuses into the underlying copper layer. An intermediate layer of approx. 4µ nickel is therefore applied as a diffusion barrier.

DIM often denotes the dimensional position of circuit board layouts and contains the data on the contour.

Dimension Layer is the dimension position in the PCB layout and contains the contour of the PCB.

Dimensions indicate the dimensions of the circuit board in its 3 axes.

Dimensional accuracy describes the accuracy in which most films depict the structures of the printed circuit boards.

DIN is the German industry standard

Direct imagesetters are newer imagesetters that scan the conductor pattern directly onto the circuit board to be exposed. Standard imagesetters emit collimated light onto the light-sensitive layer of the circuit board. For this, you need a film.

DMA stands for “dynamic mechanical analysis” and is a method for determining plastic properties. for FR4 base material.

DMS stands for “strain gauge” and describes a strain sensor that changes the electrical resistance even with a slight change in its length. They are preferably used in scales.

Donut is a shape that can be used as a bezel in PCB design. It describes a round shape, with a round hole in the middle, similar to a ring.

Double-sided circuit board is a circuit board with copper on two sides. It is often also called a bi-layer, two-layer or two-layer circuit board. The designation DK board is also sufficient because DK stands for plated-through holes and plated-through circuit boards are at least double-sided.

DPF stands for “Dynamic Process Format” and was developed by Barco. DPF data does not only contain the usual plot information for the circuit board, such as position, size, and shape. DPF files also contain network lists that are required for the electrical tests of circuit boards.

Drill void describes the occurrence of plated-through holes without the required copper pad. “Void” therefore stands for “missing part, empty space, emptiness”.

DSA-Flex stands for “Double-Sided Access-Flex” and refers to a single-layer flexible printed circuit board with a cover film open on the top and bottom for connecting components or wires (freely translated: “double-sided accessible flexible printed circuit board”).

DSC stands for “Differential Scanning Calorimetry” Differential Calorimetry – DKK) and describes a method for measuring heat absorption and release of substances. The method is used to determine the Tg of circuit board base materials.

Ductility (pulling, guiding)is the property of a material to deform plastically when overloaded before it fails. Here the copper is meant, especially in the perforated sleeves. Ductile copper is less likely to crack under thermal or mechanical stress.

Dummy usually refers to milling or drilling patterns that are used for mechanical testing of the circuit board. Before the printed circuit boards with all their structures are manufactured, it is sometimes advisable to produce an inexpensive dummy, for example, to test the placement of the circuit board in the device. In general, it also refers to a non-functional pattern

Darkroom is the place in circuit board manufacturing where films are usually developed.

DWG is a file format and stands for “drawing”. It is a format of AutoCAD that is used for the creation of technical drawings. In the PCB area, it is relevant for the mechanical design

DXF is a file format and stands for Drawing Interchange Format. It is a file format that is used to display CAD models and was developed for the AutoCAD program. In the PCB area, this format is mainly relevant for the representation of contour drawings and for dimensions of mechanical processing.


Etching is a process for surface pretreatment. By etching, the surfaces are cleaned and activated.

Circulation describes the number of printed circuit boards actually given in the production of printed circuit boards. If a total of X boards is ordered, more boards are usually “placed” to compensate for any rejects. This “additional edition” can lead to over deliveries if more printed circuit boards leave the production without problems than ordered.

Lines of the same electrical potential or field line strength

The etching factor denotes the addition of structure widths in% before the etching in order to compensate for the width reduced during the etching process. 

Etching defect is imperfections in the copper image of the circuit board. These etching errors can be either protruding or not etched copper spots, or too many etched areas. Both are permitted to a certain extent according to IPC and PERFAG.

Etching resist refers to the medium that protects the copper from the etching liquid. In the case of alkaline etching, a thin layer is usually applied to the printed circuit board structures.

Etching technology is an etching process used to remove metals. In printed circuit board production, etching technology is used particularly in the creation of copper structures. A general distinction is made between acidic etching technology (based on acid) and alkaline etching (based on an alkali/base).

Exposure is made in several process steps in the production of printed circuit boards. In conventional lyre board production, exposure of the laminate to structure the copper is essential. Furthermore, a slightly changed exposure process (longer exposure) is used for the solder mask.

E-test (electrical test or electrical test) is a procedure for testing printed circuit boards for short circuits or open connections. So-called adapters are used for the electrical test, or if there are only a few printed circuit boards, needle testers are used. By creating netlists, it is possible to check in an e-test whether a net has an open position. Testing for unwanted connections is a bit more complicated. While in the case of open connections only the start and endpoints of the network need to be approached in order to be able to determine an interruption in the conductor track, a comparison with adjacent networks must be carried out during short-circuit tests. This method is therefore considerably more complex when creating the test program, time-consuming in the case of finger testers and rarely 100% reliable in the calculation of the test routines (which would theoretically require a check from every network to every network). Likewise, excessive conductor path constrictions can often not be recognized by an electrical tester, since a constricted connection for the electrical test often still has a sufficiently low resistance in the test and the connection is rated as “okay”. Contrary to the general assumptions, an electrical test does not provide 100% security and an optical check is required as a supplement.

Eagle is a powerful software from CadSoft for creating circuit diagrams that can be automatically converted into layouts (unbundled circuit diagrams) for the production of printed circuit boards. The advantage of Eagle lies in the low purchase costs and the high distribution in the German-speaking area. The latter ensures fast and well-founded support in various online forums dealing with printed circuit board design.

ED copper stands for “Electric Deposit” and refers to a copper cladding that was applied to the base material by means of a galvanic process. A distinction is made here in particular to RA copper, which is rolled on. ED copper is somewhat more porous due to the electrolytic application. This has relatively little influence on rigid circuit boards but is relevant for flexible circuit boards when it comes to maximum bending strength. Here, rolled copper is more resilient due to the less porous molecular structure of the copper and is preferable to ED copper.

Edge clearance describes the distance that copper structures on printed circuit boards have from the contour. This minimal edge clearance can vary depending on the production line. However, the mechanical processing of the circuit boards is more relevant. While milled boards allow relatively small “edge clearances”, much higher edge clearance must be observed for punches and especially for cracks. If this is undershot, the copper structures may be mechanically damaged, which then causes burrs to rise due to the formation of burrs and cause them to flake off. In extreme shortfalls, insufficient edge clearance can lead to conductor tracks becoming too thin or being completely milled away.

Ethylenediaminetetraacetic acid or ethylenediaminetetraacetate, the tetraanion of ethylenediaminetetraacetic acid, EDTA for short, is a complexing agent and is used in analytical chemistry as complexon / titriplex II standard solution for the quantitative determination of metal ions such as Cu, Pb, Ca or Mg in chelatometry.

Express service describes the possibility to buy printed circuit boards with high time pressure and to receive them faster. The speed with which rush services are possible depends on the one hand on the technology (complexity) of the printed circuit boards and on the other hand on the ability of the circuit board manufacturer to quickly and appropriately set up its processes and machines accordingly.

Elasticity is the property of a body to return to its original shape after it has been deformed by an acting force if it is no longer there

A process in which an electrical current causes a chemical reaction is called electrolysis. This reaction is used in the manufacture of printed circuit boards to deposit metals. Here the circuit board is attached to the cathode. The anode consists of the material to be applied. This is broken down and migrates through the electrolyte to the cathode, where it settles.

Electrolytes include liquids that contain ions. In PCB manufacturing, they are contained in the electrolytic (galvanic) baths. Their electrical conductivity and the charge transport through the directional movement of ions cause the material to build up or break down on the electrodes connected to them

Electronics development describes the entire development process of electronic assemblies. He usually starts with the creation of the functional requirements, whereupon the circuit diagram is created. According to the required geometry, this is transferred to a printed circuit board. The board, components, housing, displays, cables, and other components are then brought together to form a terminal. The finished product can be used for test purposes to incorporate the results into a redesign.

Embedded component is a relatively new trend in printed circuit board manufacturer, which can increase the packing density immensely. In principle, it is about integrating components directly into the printed circuit boards (usually in the inner layers of a multilayer). This saves space on the outer layers and contributes to further miniaturization of assemblies.

Embedded resistor is a type of embedded component, only that it specifically affects the resistors and thus defines the most widely used method of component integration. A special resistance paste is printed on the inner layers and integrated through exact thickness and structure control, as well as cutting of lasers. This paste has a defined conductance so that corresponding resistances can be generated by determining the width and height. As a technical limitation, it is often mentioned that the resistance range of all embedded resistors must be in a similar range since a paste is selected in accordance with this range. This is usually only economical if it affects a significant proportion of the resistance that is to be embedded in the multilayer

EMC is the abbreviation for electromagnetic compatibility. The EMC thus describes the desired state in which modules do not interfere with one another in their function, that is, “tolerate” one another. This can pose various challenges for the manufacture of printed circuit boards, but these must be communicated to the manufacturer by the designer of the assembly.

End copper describes the copper thickness on printed circuit boards, which is composed of base copper and build-up copper and thus describes the end thickness of the copper structures on the board. Certain standard thicknesses such as 35 µm are common here

Endless-Flex describes the manufacturing process for flexible printed circuit boards. Here the base material is unwound from a roll, goes through the manufacturing steps as a belt and then as a finished product, again wound onto a roll. Only the final cuts are punched out or lasered from this later.

End surface identifies a selection of coatings that can be applied to the copper of the printed circuit boards. Depending on the application and preference (e.g. due to optimized soldering profiles), there are various tin surfaces (HAL lead-free or chemical Sn (chemical tin), lead-tin surfaces (HAL-leaded, not RoHS-compliant)

Engg generally stands for “engineering” and is used by PCB manufacturers in Asia or America in connection with prototypes. The “Engg lot” that often appears means nothing more than test samples for functional tests or quality checks before ordering the circuit board in series.

English units denote the use of inches and mils in the dimensioning or layout data output of printed circuit boards. Depending on the setting of the programs, these sizes and position specifications can be output in metric or English units. This is largely irrelevant for the manufacture of printed circuit boards, provided that there is a definition in the data to which unit system the information relates.

ENIG stands for “Electroless Nickel-Immersion Gold” and is a short word for chemical nickel-gold, an end surface for printed circuit boards. However, the word ENIG alone says nothing about the chosen layer thicknesses of nickel and gold. It is only a matter of naming the process and the components, not an exact definition of the board surface.

ESPI stands for “Electronic Speckle Pattern Interferometry” is an optical analysis method for measuring deformations.

Eurocard is a standardized printed circuit board with the dimensions 160x100mm² (see European format). This circuit board format is, therefore, a standardized size of slide-in boxes. It has relevance for the production of printed circuit boards in that it is often used on the one hand as a price basis (price per euro card “) and for the size of the printed circuit board cuts in production. Many manufacturers have decided on formats that are optimal for the Arrangement of a certain number of maps of Europe is designed.

Eutectic comes from the Greek and means “melt well” and requires at least 2 metals. In the eutectic, the alloy immediately changes from the solid (solidus) to the liquid phase (liquidus) without the solidus/liquidus area. Since the melting point of a eutectic alloy is significantly lower than that of pure metals, such alloys are preferred for soldering. The eutectic was particularly relevant in the manufacture of printed circuit boards for the application of the tin-lead end surface. But is no longer used today because it is not RoHS compliant.

Eutectic point is the point in a material composition at which the melting temperature is the lowest. An example relevant for the production of printed circuit boards is the tin-lead mixture. With a ratio of approx. 63% tin and 37% lead, the soldering temperature is only slightly above 180 ° C. The new RoHS-compliant solders without lead require temperatures above 240 ° C (melting point of tin (Sn) is 232 ° C).

Excellon is a machine manufacturer and is an NC data format used for drilling and milling machines. In addition to the necessary coordinates, Excellon contains so-called tool information. A tool (tool) for milling or drilling is assigned four different values ​​here: size (usually in inches), stroke (speed of immersion of the tool) and feed rate (in the case of milling cutters, the speed at which the milling cutter moves in the board) ), and speed (revolutions per minute).

Express service is a term for the production of printed circuit boards in a very short time.

Extended Gerber is a widely used data format for displaying structures on printed circuit boards. The word “extended” indicates that the data already contains information on the sizes and shapes. This differs from standard Gerber, where an aperture table is required for interpretation.

Eccentric press is a punching machine that is used for the separation of printed circuit boards. The name “eccentric press” comes from the eccentric shaft used, which is driven by a belt via an electric motor and wedged at the operator’s command with a clutch to convert the force of the rotary movement into a stroke.


Flexural strength is a term used in statics that can have different meanings for printed circuit boards. Firstly, the rarer requirement for high stability, in the event that the circuit board is under bending stress. On the other hand, the bending strength is often relevant for flexible printed circuit boards in order to draw conclusions about the possible bending radii and the general flexibility.

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Hardening is part of every varnish application on the printed circuit boards. Curing takes place either by heat (oven) or by adding infrared light. A distinction must be made here between pre-curing and final curing. The pre-curing allows the varnish to solidify, but it is then possible to develop unexposed areas. After the final curing, even unexposed areas can no longer be removed, which is also desirable.

Hole spacing is the distance between two holes. This drilling distance is important because if the minimum distances are undershot, the “web” between the holes can break. This web break can then ensure that the bore is “clogged” and therefore cannot be properly contacted. In the case of drilling distances in the design phase, it should be borne in mind that the holes are later provided with drilling allowances by the manufacturer. The drilling distance in the layout, therefore, does not correspond to the actual drilling pattern. Printed circuit board manufacturers therefore often specify higher drilling distances so that they can add the addition later and take the exact calculation off the layout’s mind.

Hole pattern is the appearance of all holes on the circuit board.

Hole is a hole in the circuit board. This hole can be conductive, ie filled with copper. These holes are then called “plated through holes” or DK for short. If there is no copper in the hole, it is a non-conductive or non-plated-through hole, NDK for short.

The drill pad is the opposite of the drill cover sheet, see “Drilled cardboard”.


Inorganic chemistry or inorganic chemistry is the chemistry of all carbon-free compounds, carbonic acid and hydrocyanic acid, and the salts thereof.

Iceberg Technology describes a process for the production of thick copper circuit boards, from a copper thickness of approximately 200 µm. In iceberg technology, a copper foil of the strength mentioned is laminated, exposed, developed and the conductor track structures (mirrored) are pre-etched. Subsequently, these copper foils, which are structured on one side, are first provided with filling pressure in order to make the gaps even). Then the foils are glued/pressed with this side down onto a carrier. With double-sided boards, the same process is carried out again for the other side. The result is a standard printed circuit board with a copper cladding of different thicknesses. This now enables the structures to be etched in more detail in accordance with the planned conductor pattern. Since, in particular, the undercutting of thick conductor tracks is a problem with thick copper circuit boards, the copper to be etched is limited here by integrating the thick copper into the carrier. The resulting structures are therefore partly buried in the base carrier and partly they protrude from the circuit board. This appearance gave the process its name: iceberg technology since copper structures “lie below the surface and only the” (iceberg) tip “looks out”.

Iron (III) chloride is a chemical compound of iron (III) and chloride ions. The Roman numeral III indicates the oxidation number of the iron ion (+3 in this case). Iron (III) chloride belongs to the group of iron halides. Iron (III) chloride can oxidize and dissolve copper

Initial sample test report is a document that records the testing of a printed circuit board according to specified test criteria. Initial sample test reports can be of different levels of complexity and meaning. The occasion can also be a redesign, a redesign or a sample of the manufacturer’s quality. Depending on the arrangement, initial sample test reports are created both by the PCB manufacturer itself and by the recipient.


Jump is a term from screen-printing technology, e.g. when applying the identification print, whereby the screen fabric behind the squeegee stands out again from the printed object to avoid smearing.

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Loader is device that automates the loading of machines with the printed circuit boards. Loaders are customary in drilling machines so that once they have been set up, they can be loaded with a “magazine” of blanks to be drilled and processed without further manual intervention. It is also possible to load the loader with different types of circuit board blanks and to program the drill accordingly so that the corresponding programs are drilled with the different blanks. Once a blank has been drilled, it is pushed back into the loader for drill loaders in order to clear the drill table for the next cut. In addition to drilling machines, loaders are also used in various continuous systems. Fan loaders are often used to place circuit boards on the conveyor belts at a preset speed.

Lead (chem “Pb”, Plumbum) is a toxic metal that is used as an alloy component of solder. With the introduction of the RoHS / WEEE standard, lead was largely banned as an alloy and is only available today from a few PCB manufacturers on explicit request.

Lead-free is a regulation introduced to protect the environment, which is binding for the majority of electronic applications today. There are exceptions for certain industries in which lead-based soldering can continue (as of 2010), as there is no long-term experience with lead-free printed circuit boards. This mainly affects the automotive, aviation, military and medical technology. Lead-free manufacturing is often associated with RoHS, but RoHS regulations prohibit more substances than just lead. Lead-free printed circuit board production is considered to be largely mastered and standard. The processes and materials used have been successfully adapted to the higher soldering temperatures.

Lead tin, better tin-lead since 60% tin and 40% lead, (SnPb) is the name for the eutectic mixture of lead and tin that was used before the introduction of lead-free electronic products. Since some industries are still allowed to manufacture lead electronics, the process is still available on the market – in decreasing amounts. The advantage of tin-lead lies in the eutectic point, which gives this composition a lower melting point than pure tin or pure lead. Soldering is, therefore, possible at a lower temperature, which means less thermal stress for the printed circuit boards. The disadvantage of tin-lead is that it contains lead, which causes severe environmental pollution.


In the manufacturing process, additive processes refer to the complete application of the copper tracks to the carrier. The subtractive method only etches away. The semi-additive process is customary, where an existing copper layer is only reinforced at those points where conductor tracks are desired, and the unreinforced part is then etched off.

Barely used today. Heat the electroplated tin-lead layer to flow so that it runs around the flanks of the copper.

The printed circuit boards to be able to handle them better when assembled.


Nozzle block is a carrier of several nozzles in machines. Through these nozzle assemblies, various liquids can be sprayed onto the printed circuit boards with pressure. It is important that the spray pattern is as uniform as possible, which is achieved by additional oscillation. The nozzle assemblies are serviced regularly.

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Outgassing refers to the escape of air from the circuit board during soldering. This undesirable event is mostly due to moisture within the base material. In the worst case, outgassing can cause through-plating sleeves to break, so that the moisture can evaporate. This can be prevented by templating before soldering so that the base material of the circuit boards can dry out slowly.

The outside edge denotes the contour edge of the circuit board.

The outer layer is the top and bottom of printed circuit boards. A circuit board has either one or two outer layers and up to n inner layers. Only these outer layers can be fitted with components later.

One-off production describes the opposite of combining different circuit boards on one production blank (also called pooling). The one-off production has various advantages but also disadvantages. The advantage of one-off production of printed circuit boards is that reorders are often cheaper, the board production can be done faster and existing work cards, tools in the form of films, adapters and programs are used, which in turn reduces the risk of errors. One-off production is disadvantageous if the boards are only to be produced in small and one-time quantities and no-repeat orders are planned. For some technologies, however, one-off production is essential if, for example, various special features (board thickness, copper thickness, type of material, color, short-term appointment, etc.) occur in combination, making a combination with other orders very unlikely.


Peel-off varnishes are mainly used on printed circuit boards, which have to run several times over wave soldering systems. In order to prevent the initially empty holes on the printed circuit board from being filled with tin, the printed circuit board manufacturer applies a thick, tough varnish to these areas, which protects the holes. If the protected areas are to be populated later, the peelable varnish can be easily removed from the board by hand and then reveals the intact and free assembly holes.

Peel strength describes the bond strength between copper and printed circuit board, or between copper and the end surface. In order to ensure that the printed circuit boards can be used properly, these areas must be well connected.

Pull-off tests are carried out to check the pull-off strength. In order to check the adhesive strength of copper on the base material of the board, certain areas are subjected to a tensile load and this is measured. Depending on the material and IPC, different minimum forces can be endured. The removal test of end surfaces on the copper of the printed circuit board is usually carried out using adhesive tape. This is glued over the finished areas and then abruptly torn off at a 90-degree angle. The test is passed if no detachment of the end surface can be seen on the adhesive tape.

Failure describes a process of wastewater treatment, whereby the heavy substances sink to the bottom.

Pumice flour is mixed with water in pumice machines to roughen copper surfaces on printed circuit boards.

In galvanic treatment, a “similar” composition is often “rinsed” before a subsequent bath with a significantly different composition in order to avoid carryover or to clean the surface.

Precious metal is particularly corrosion-resistant metals. Gold and silver, in particular, are therefore used in the manufacture of printed circuit boards for the finishing of surfaces.

Press-in technology is a solderless connection technology for circuit boards. Since the electrical connection takes place here via a press contact, the required hole tolerances are of considerable importance for the production of printed circuit boards. While a higher tolerance can be compensated by the inflowing solder when soldering components, holes that are intended for press-fit technology have to be checked within narrow tolerance ranges. This is possible by communicating the required tolerances for a certain number of drill diameters.


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Recording is a registration system for fixing printed circuit boards during manufacture. Most machines have pick-up systems, some of which are different. It is therefore often necessary that the production cuts allow various different recordings

Reference hole is a hole in the circuit board from which other holes, contours or copper areas are dimensioned. Often, these reference holes are mounting holes for which the positioning of the other components on the circuit board must be exactly correct.

The reference point is a term that is of great importance in CAD / CAM in connection with the different machines to be operated. Depending on the recording system, machines can have different reference points. These must be taken into account accordingly in the data preparation. When looking at the finished production data, it may appear that the drilling program, films, and milling program are completely offset from one another. However, if the different machine reference points are taken into account, the layers of the printed circuit board again cover each other.


Suction characterizes the suction device on drilling and milling machines. This sucks off the drilling and milling dust generated during these processes. It should be noted that circuit boards that are too small to be held by the hold-down device can also end up in this extraction system. Complex masking or milling without extraction is required here.

Shields are conductor tracks or areas in layouts that have a ground or GND potential and are thus intended to prevent “crosstalk” of signals from one conductor track to another.

sewage is generally the water that can be disposed of in the sewage system. In order for this to happen, various pre-purification and filter stages for treating the wastewater must be carried out. The water discharged into the sewage system then complies with environmental requirements and no longer contains polluting substances.

sewage system is an indispensable component in the production of printed circuit boards. Various substances are filtered out of the water and separated for environmentally friendly disposal.

sewage treatment describes the process in which wastewater generated during the manufacture of printed circuit boards is treated in such a way that it can be fed into the wastewater cycle.

Wastewater disposal can describe both the disposal of the treated water in the sewage system and, in some cases, the collection of the same

Seaweed form in standing rinsing baths. This must be prevented at all costs. This means that during long production breaks, for example over public holidays, these and other bathrooms have to be re-scheduled. Start-Up time for printed circuit board production is, therefore, more time-consuming after a long stop in production.

Discoloration of metal surfaces when heated

Suction is a term that is used in circuit board production mostly in the context of positioning the films before exposure. Here, the films are first positioned on the board and then fixed by vacuum pulling on the circuit board so that the film cannot slip. A further suction takes place with some assembly machines, which guarantee the fixation of the circuit board by suction. It is often necessary to close the vias (via filling pressure) so that sufficient suction pressure can arise.

Stamp outline denotes printed circuit boards with holes on the contour edge. Often, these half-open holes are plated through on the edge of the board. The difficulty here lies in the sequence of bores, millings, and vias because if these are not adapted or changed accordingly, the router pulls the copper sleeves out of the half-open bore when milling out the circuit board. The production of stamp contours is, therefore, a question of the PCB manufacturer’s know-how.

Step-through filling pressure is a non-conductive paste that is filled in step-throughs (VIAs) to seal them. This is usually necessary if printed circuit boards have a large number of holes and are later fixed by means of vacuum draw. In order to achieve better adhesion of the circuit board, the plated-through holes are closed for this purpose, which was determined purely as conductors, that is to say, should not receive any components. In addition, a through-filler pressure is used for inner layers in which buried holes have been inserted. Intermediate filler pressure is often also called “plugging”. At the moment, however, plugging is only used to mention the closing of holes, which is provided with a “copper lid”. The areas of application are more extensive and the paste, as well as the process, deviate from pure transfer pressure.

Setup costs arise for the “setup” of machines, creation of programs and work cards, as well as for the production of necessary tools, such as e-test adapters or punching tools. Setup and set-up costs are often used interchangeably. It is, therefore, more precise to set up “one-off set-up costs” (tools, adapters, films) and “recurring set-up costs” / “set-up costs” (creating work cards, activating the archived documents, reading the programs into machines and activating documents, etc.) to speak. Some circuit board manufacturers show the setup costs separately, others (especially for prototypes) include these in the unit price. For very large series, set-up costs (both recurring and one-off) are sometimes even waived. This depends on whether the unit price share of the boards predominates to such an extent that the set-up costs are no longer significant.

Setup describes the process before the actual production start or production step. Both the integration of individual layout data into the production frame (CAD) and the reading in of drilling, milling and e-test programs are part of the facility in the production of printed circuit boards. Added to this are the positioning of films in imagesetters, the selection of the right materials, the correct setting of machine times and values ​​and various other more or less unique processes in the respective batch production of a certain type of printed circuit board.

Single-sided circuit board identifies circuit boards with copper structures on only one side. These have no plated-through holes since the components only require electrical connections on one side. Single-sided printed circuit boards are therefore usually considerably cheaper and, especially in extreme cases, can be manufactured more quickly. There are no lighting processes, as well as through-plating of the circuit boards.


Thick gold usually refers to a surface on the circuit board that goes beyond the relatively thin chemical nickel-gold (0.05 ~ 0.12 µm). Basically you start talking about thick gold as soon as it can be bonded with gold wire (0.3 ~ 0.8µm). However, since gold thicknesses of up to approx. 3 µm are possible, the pure term “thick gold” is not always sufficient. It reveals little about the areas of application and can mean both bond gold (soft gold) or plug gold (hard gold).

Thick copper refers to printed circuit boards with thicker copper. There is no precise definition of the thickness from which thick copper is used, but this terminology is usually only used by manufacturers when it concerns beyond 100 µm, sometimes 200 µm copper. 70µm copper is not a standard (35µm), but with a range of up to 400µm that is possible today, it is not called thick copper.

Term for a wound coil/inductance, since it represents a resistance with alternating current, i.e. it throttles the current.


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Vias are holes that have received copper plating. This copper plating on the edge of the plated-through hole (copper sleeve) creates contact between the different layers. In addition to vertical contacting, plated-through holes offer advantages when soldering components. The copper in the hole ensures a complete connection of the component. Plated holes are considered fail-safe for wired components.

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Wastewater-free printed circuit board production describes the recovery of all rinsing and process bathwater in order to treat it and add it back to the manufacturing process. However, the word is often used for advertising and it is a contradiction to the fact that wastewater describes the water that is discharged into the sewage system. If there is no treatment of the water used, so that this must not and will not be drained into the sewage system, some people do not see any wastewater. All contaminated water is picked up by service providers

Work plan describes a card or booklet that contains all the information needed to manufacture the circuit board. This includes the technical execution, quantity, date, as well as the exact sequence of the work steps to be carried out. A flawless work plan that is well prepared by the work preparation department is the basic prerequisite for high-quality, correct and punctual manufacture of the printed circuit boards.

Wetting describes the uniform acceptance of liquid substances on the surface. In the HAL process, in particular, wetting is a challenge because temperature, immersion time and surface cleanliness are decisive influencing factors.

Wire bridge is a replacement for a conductor track. In some cases, wire jumpers are used as repair measures, but in some cases, the design of wire jumpers on the circuit board is also intended from the start. The latter is often the case if only a small number of conductor tracks is responsible for the fact that an additional layer of the circuit board must be added. It is then a question of the component calculation to what extent the laying of wire bridges is allowed on the one hand and is cheaper on the other hand than the production of a printed circuit board with several layers.

Wire laying technology is used in simple test setups with prototype printed circuit boards on perforated board. The wire is soldered onto a breadboard, which represents the conductor track. The wire laying technique is very time consuming and therefore only suitable for sample circuit boards.


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