banner
Through via, Blind via, Buried via in PCB

110 Published by FASTPCBA 4月 10,2021

Via exists where there is a PCB: the wiring on different layers must be connected by via, the components of the SIP/DIP package must be fixed by via, and the heat dissipation of the power supply cannot be separated from via…

The types of via are simply divided into three types: Through via, Blind via, Buried via


Of course, via is not innate. It is processed with a drill when the board is made. It is very interesting to study how to drill the three kinds of holes. Although there are only 3 types, there are many processing methods.

1. Through Via

With the processing method of Through via, some friends will definitely say: “It’s not easy. Take a drill and drill it to the end, isn’t it all right?”

Experienced friends must know that there is a word: “thickness-to-diameter ratio”, which is the ratio of the thickness of the finished board to the diameter of the via. If the thickness-to-diameter ratio is too large, such as more than 16:1, it cannot be drilled to the end. What should I do? General practice: design the board thinner; design the aperture of the via larger. If you can’t do both of these, the board can’t be thinner, otherwise the layers won’t be enough; the via has to use such a small hole, what should I do?

A hole can be drilled twice, so we can use two different drill nozzles.

2. Blind Via

Through Via can only use mechanical drills, Blind Via can also be laser drilled. The difference between mechanical drills and laser drills: The hole diameter of mechanical drills is large, ≥8mil, and the thickness that can be drilled is related to the diameter of the via, and the thickness-to-diameter ratio is up to 1 :1; The aperture formed by the laser is only about 4mil, and the thickness that can be drilled is only about 4mil.
Method 1:


Method 2:

3. Buried Via

The hole is buried in the PCB. From the surface, there is no hole at all. How to do it First make the middle board, drill and electroplate it yourself, and then use 1 core or 1 board each on top and bottom, and press the top, middle and bottom together.

PCB board short circuit six inspection methods

PCB board short circuit six inspection methods First, opening the PCB  board design on the comput...

Do you like ? 885

Read more
Common PCB circuit board fault detection method

Common PCB circuit board fault detection method   Common PCB circuit board faults are mainly...

Do you like ? 1,234

Read more
During circuit board soldering process, what should be paid attention to?

During circuit board soldering process, what should be paid attention to? 1. Possible conditions...

Do you like ? 1,636

Read more
What do the “special pads” on the PCB do?

What do the “special pads” on the PCB do? First, the plum pad 1, The fixing hole need...

Do you like ? 853

Read more
What are the requirements and specifications for pwb positioning holes?

What are the requirements and specifications for pwb positioning holes? What is a PCB positioning...

Do you like ? 754

Read more
Circuit board spray tin  function and technics procedure introduction

Circuit board spray tin  function and technics procedure introduction The so-called spray tin is ...

Do you like ? 744

Read more
Surface Mount Technology (SMT)

Surface Mount Technology (SMT) Surface Mount Technology (SMT), also known as surface assembly tec...

Do you like ? 844

Read more
How to wash the pcba

How to wash the pcba After the PCBA processing process is completed, it is often seen that there ...

Do you like ? 787

Read more