the Advanced Technology of PCB Multilayer Circuit Board (Part 5)

The commonly used additive method is to form the circuit after the full-board electroplating with copper, and the uniformity of the coating of the full-board electroplating will be much higher than that of the pattern electroplating. Therefore, in order to use the additive method to make fine lines, the distribution problem of the pattern electroplating layer must be solved first. Using positive and negative pulse electroplating power supply, after adjusting the positive and negative pulse time, the positive and negative pulse current and other parameters, the pattern can be electroplated to get a more uniform coating distribution.

4. Electroplating technology to fill blind holes 　　

The conventional HDI laser blind hole process faces the following problems: There are voids in the blind holes of the SBU layer, and air may remain in the blind holes, which affects reliability after thermal shock. The conventional method to solve this problem is to fill the blind holes with resin through the pressing plate or fill the blind holes with resin ink plugging process. However, the reliability of the boards produced by these two methods is difficult to guarantee and the production efficiency is low. In order to improve the process capability and the HDI process, electroplating is used to fill the blind holes. The advantage is that the blind holes can be filled with electroplated copper, which greatly improves the reliability. Making circuit patterns or superimposing blind holes greatly improves the process capability to adapt to customers’ increasingly complex and flexible designs.

The ability of electroplating to fill blind holes is greatly affected by the material of the board and the hole type of the blind holes. To achieve good blind hole filling and the surface copper thickness meets the standard, advanced equipment, special copper plating solution and plating Copper additives, these are also the focus and difficulty of this technology.