Everything you need to know about Microvia
The circuit board is the heart of electronics and computing devices. This circuitry transmits signals from control prompts to the screen. For example, you can find a circuit board in your smartphones. When you touch on the screen, you activate one of the signals on this circuit board every time. Basically, vias generate these signals to perform different tasks on your devices. So all it happens due to microvia.
This article explains in detail what are vias, micro vias, and its type. We will further express why microvia is better than other vias. In short, after reading this article, you will be familiar very well about microvias and their usage. So continue reading this article!
What is via?
Vias are special holes that pass through the layer of printed circuit boards. You can consider these as a conductive path. You can pass an electrical signal between different circuit layers by using these vias. Vias pass through different levels on a circuit board.
Depending on the design of the circuit, holes may penetrate from the top to bottom layers. Some circuits need to connect two or more inner layers and so on. Vias are the most crucial components of the circuit board. Different types of vias have their own purpose. So their usage varies on the basis of the design of the board.
There are three major types of vias. The first one is the through-hole vias. Via in the pad is another type of vias. Furthermore, the third one is microvia. So in this article, we will only talk about micro vias.
What is microvia?
Micro vias are the remarkable component of high density interconnect boards. These are a special type of vias having size 150 micrometers or less. Due to their small size, designers prefer micro vias and use them in HDI boards. The microvia need far less space as compared to other vias on the board. In a micro via, copper plating connects different layers of the board with each other.
Structure and specification of microvia
Micro vias can pass through two adjacent layers of the circuit. But it can’t pass through any further. If you want micro vias to pass through from multiple layers, you will have to stack these vias accordingly.
From the manufacturing point of view, stacked microvia is costly. Furthermore, it is a time-consuming process as well. Most of the time you need to stack just one micro via over other. The ultimate limit to stack microvia over each other is four. However, manufacturers use four micro vias in the PCB manufacturing process due to their high costs.
Staggered micro via is another suitable alternative to the stacked micro via. In this case, you have to use micro vias like a staircase. This means you place a second or third micro via a step forward to the previous one. Likewise stacked microvia, staggered vias are also costly. Moreover, you can use these to produce a multilayer circuit board.
Costs of microvias
The circuit boards with micro vias are more costly as compared to other traditional boards. There are different reasons behind the increment of cost. First and foremost, the process of manufacturing becomes more complex in this scenario. Moreover, there are more vias in the circuit boards due to their smaller size. So you need to fill more vias with different materials resulting in the increment of cost.
Different types of microvia PCB
There are three different types of microvia. The first one is blind micro vias. Skip micro via is another popular type. The third one is buried microvia. So you can use individually or combined to increase the density of printed circuit boards.
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Blind microvia
If a microvia starts from the outer layer and stops to an inner layer known as blind micro via. It means it doesn’t penetrate both out layers. By using blind micro via, you can enhance the density of wires on the circuit boards.
If you want to route a signal from the outer layer to an inner layer, blind vias are very useful. They provide the shortest distance in this scenario. On the HDI board, these micro vias use to optimize the space of multilayer boars. For example, if a board has four layers, you can place these vias either on the top two or the bottom two layers.
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Skip microvia
In some situations, a microvia penetrates two whole layers. So any via that fit this description known as skip vias. However, most manufacturers don’t recommend this via. It is because the nature of this type of vias makes the plating process very complicated.
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Buried microvia
A micro via that connects two internal layers of the board known as buried micro via. These vias are not visible from the outer layer. So if you want to include buried via your circuit board. Then you will have to drill the inner layer before applying the outer layer. You can connect two inner layers by using buried via. You can use any mechanical tool for drilling. However, the best alternative method is to use a laser for this purpose.
You must pay attention to the aspect ratio of the hole size before applying micro via a circuit board.
What are microvias used for?
Look at the trends of current electronic and computing industries. Both industries are looking for lighter, smaller and reliable electronic devices. It means industries are considering these appearance factors besides functionalities. Moreover, performance is the crucial factor to put a device in trending.
To make a device lighter and smaller means you need to create circuit boards smaller and lighter. If circuit boards are giant, it is impossible to create a smart device. Moreover, if the circuitry is giant, it will consume more energy. So battery timing will be low again. All industries want to consume batter as low as possible. So small circuits will be handy in this situation.
In addition to this, small circuits produce less heat. So again battery consumption will be low here. Moreover, these small circuits have excellent performance. Your smartphone performance is the witness! To increase the functionality of a circuit, you need a complex routing mechanism. Smaller circuit boards came into existence such as Ball Grid Arrays due to the higher numbers of input and output. It means when I/Os increase, you need to increase the circuits traces on the same boards.
To tackle such problems, researchers came with various solutions. One of the solutions was to use high density interconnect technology with micro vias. By using many vias, the circuit board can carry more traces. More traces means a denser placement of different components. The main purpose of microvia is to increase the density of the circuit board. Micro vias and HDI technology combined make it possible to carry six components in a specific area. Prior, to this area, conventional methods just carry four components.
Why is microvia better than other via?
The PCB manufacturing process is an expensive process. This process becomes far more costly when you need to create complex circuitry. So it is a fact that each layer in the circuit boards costs a lot. Therefore, when layers increase, the cost of the circuit board will increase.
So you can utilize microvia to replace the conventional through-hole vias. Through-hole is a very common terminology. It means normally when we talk about vias, we are considering through-hole vias.
What would happen if you replace through-hole vias with micro vias? It will decrease the number of layers which means reducing the manufacturing costs.
Besides this, a minor replacement can’t only cut decrease the cost. But also enhance the electrical characteristics of the PCB. In the age of technology, people go with the smaller and lighter devices. Therefore, high density and multilayer circuit boards are the need of this era.
Besides functionalities, microvia utilizes the minimum space of the board. Furthermore, they come in just two are three layers. So the manufacturer gives priority to these vias.
In addition to this, micro vias are available in a wide variety of patterns and materials. It makes this technology one of the finest choices of complex circuit boards. Such as staggered, via in pad and non-conductive are some of the examples. It further includes staked, offset and copper-filled material.
You can boost routing across multiple layers by using stacked micro vias in those applications requiring more than three layers. Furthermore, it also gives a built-in thermal regulation.
Final words
Now you are familiar with microvia. So the core purpose to utilize microvia is to gain high density as much as possible. For this purpose, you can use any type of microvia according to your needs. Although these are a little bit costly, give you the best results.
When we talk about the PCB manufacturing companies, MOKO Technology is one of the biggest names. For any type of electronic solution, feel free to contact this company. You will have reliable and desired results!
