PCB News - PCB design of blind and buried vias

First of all, you have to understand how the multilayer board is made, and understand how the holes are processed to make the PCB design of blind and buried holes. Nowadays, the multilayer PCB board is generally made of

Multiple two-layer boards are laminated. For boards with only through holes, just press a few two-layer boards directly and then punch holes. It is very simple (pay attention to the thickness of the PCB board and

Design of the size ratio of the aperture: when the depth of the hole exceeds 6 times the diameter of the drilled hole, it cannot be guaranteed that the hole wall can be evenly plated with copper), and it is more troublesome if there are blind buried holes

One point: For example, an 8-layer board 1-2 \ 3-4 \ 5-6 \ 7-8 (here are 4 2-layer boards) There are several processing methods

First of all, let's see how to do the first order

1) The simplest and most common is to first punch these 4 two-layer boards (that is, blind buried holes), respectively, there are two kinds of blind holes such as 1-2 \ 7-8 and \ 3-4 \ 5-6

Such two kinds of buried holes, and then press the four two-layer boards together and then punch them, there will be 1-8 through holes, so that only one press is made, the production is simple, and the cost is relatively simple.

Bottom. Due to the different requirements of the PCB stack, the different distribution of the wiring layer, the GND and the Power layer, etc., the first processing method cannot meet the design requirements.

Yes, so we have to change the design and production.

Let's take a look at how to do the second order

2) (1-2 + 3-4) + (5-6 + 7-8) Here, the four two-layer boards must also be punched (that is, blind buried holes), respectively, there are 1-2 \ 7-

8 Such two kinds of blind holes and \ 3-4 \ 5-6 such two kinds of buried holes, and then press (1-2 + 3-4) to punch, there will be a blind hole of 1-4, and then (5-6

+ 7-8) Pressing and punching, there are 5-8 blind holes, and then the two 4-layer boards are pressed and punched, and there are 1-8 through holes, so although there are two more Hole, but

It is pressed twice, the production is more complicated, the defect rate is high, and few factories are willing to do it

3) (1-2 + 3-4 + 5-6) + 7-8 or 1-2 + (3-4 + 5-6 + 7-8) I won’t say more

Some people think that if I only make one or a few blind buried holes, it won't be expensive to go there, right? But in fact, due to the complete change in production methods, the cost and drilling are very high.

Multi-blind buried holes are almost the same.

Some people design blind buried holes in a mess. For the 8-layer example above, he designed holes 1-6 and 3-8. How do you design the factory to press it?

If you do 1-6, you can't make 3-8 holes. Some people are even more overly. They also design holes like 1-3 and 5-7. How do you want the factory to process it? Use 3 layers

The board is laminated to the 1-layer board?

I believe you will be helpful if you look at it

In protel99se, after pressing O + K, there is a Drill Pairs button in the lower right corner, you can set the drill pairs there, so you can change the routing

When layering, as long as the drilling pair setting in this is satisfied, the software will automatically help you add the blind buried hole.

In powerpcb or pads, setup --> Drill Pairs...