blind vias impact the overall thickness of a PCB
In PCB manufacturing, blind vias are holes in the board that connect different layers but do not touch the surface of the layer. They are also known as buried vias. Blind and buried vias are typically used to create connections between the inner layers of a PCB. They are not to be confused with through-holes, which run completely through the entire stack and connect all the layers of a circuit board.
Blind and buried vias are a common feature of high-density interconnect PCBs, or HDI PCBs. They are used to add more connection points and reduce the overall thickness of the boards. They are particularly useful in mobile devices, laptops, and other small electronics that need to be as compact as possible.
A blind via is a hole that does not have the benefit of being visible on the final printed circuit board. It is drilled into the copper layer of the PCB to make a connection between the layers. The drill hole must be a certain ratio of the drill diameter to the depth, and it must not percolate the rest of the copper layer on the PCB.
The advantage of using a blind via pcb is that it allows you to create a connection without affecting the signal flow. However, this method can be problematic if the drilled hole is too large, since it may cause problems with the electrical performance of the PCB. When the drilled hole is too big, it may cause crosstalk and interference between traces on the board. In addition, the hole can cause thermal stress, which will lead to voids or pin holes in the solder joints.
How do blind vias impact the overall thickness of a PCB?
To avoid this issue, it is important to check your gerber file for blind and buried vias. You can do this by looking for multiple drilling files in the gerber file, including drl1-2, drl1-3, drl1-4, and so on. The drilling files should have a ratio of the drill diameter to the hole depth that is appropriate for the type of via you are planning to use.
In addition to ensuring the quality of your PCB, blind vias can also be beneficial for the manufacturing process. This is because they can help to eliminate the need for etching the entire area surrounding each hole and can save time. In addition, they can help to improve the laminate resiliency of your PCB, which can reduce damage from mechanical stresses.
Both blind and buried vias can impact the overall thickness of your PCB, so it is important to choose them carefully. In general, you should only use them when they are necessary. If you are unsure whether or not to use them, it is best to consult with your manufacturer for advice. This will help ensure that your boards have a high-quality design and will function correctly. Additionally, it will save you time and money in the long run.
Another reliability concern associated with blind vias is their susceptibility to mechanical stress. Since blind vias terminate within the PCB rather than extending through the entire board, they are more vulnerable to mechanical forces such as bending, twisting, or thermal expansion. Excessive stress on the PCB can cause the blind vias to crack or delaminate, leading to intermittent or permanent electrical failures. Therefore, designers must carefully consider the mechanical integrity of blind vias, especially in applications subject to harsh environmental conditions or frequent handling.
