Differentiation of PCB boards between HDI boards and blind buried vias
HDI belongs to a kind of circuit board, which is called highDensityInterconnection. High-density interconnect boards Currently, high-end electronic products are generally HDI board products.
Blindvias: A blind hole is a type of via that connects the inner trace of the PCB to the trace of the PCB surface. This hole does not penetrate the entire board.
Buriedvias: Buried vias are only connected to the via type of traces between the inner layers, so they are not visible from the PCB surface.
With the development of portable products in the direction of miniaturization and high density, PCB design is becoming more and more difficult, and higher requirements are imposed on the PCB production process. In most of the current portable products, the BGA package with a pitch of 0.65mm or less is designed using a blind buried plate. So what is a blind buried hole?
A blind via is a type of via that connects the inner trace of the PCB to the trace of the surface of the board. This hole does not penetrate the entire board.
The buried via is only connected to the via type of the trace between the inner layers, so it is not visible from the surface of the PCB.
The circuit board with buried blind holes is not necessarily the HDI circuit board, but the general HDI board has blind holes, and the buried holes are not necessarily. It depends on the product of your order of several stages.
described as follows:
The first order of the 6-layer circuit board, the second order is for the board that needs laser drilling, that is, the HDI board.
6-layer circuit board first-order HDI board refers to blind holes: 1-2, 2-5, 5-6. That is 1-2, 5-6 requires laser drilling.
The 6-layer circuit board second-order HDI board refers to blind holes: 1-2, 2-3, 3-4, 4-5, 5-6. It requires 2 laser punches.
First drill the buried hole of 3-4, then press 2-5, then drill the 2-3, 4-5 laser hole for the first time, then press the second time 1-6, then the second time 1-2 , 5-6 laser hole. Finally drilled through hole. It can be seen that the second-order HDI board has been pressed twice, two laser drilling.
In addition, the second-order HDI board is further divided into: a second-order HDI board with a wrong hole and a second-order HDI board with a stack of holes. The second-order HDI board with a wrong hole means that the blind holes 1-2 and 2-3 are staggered, and the second-order HDI of the stacked holes is The board refers to the blind holes 1-2 and 2-3 stacked together, for example: blind: 1-3, 3-4, 4-6.
And so on, third order, fourth order... are the same.
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