Treatment before copper sinking

1. Deburring: The substrate goes through a drilling process before copper sinking. Although this process is prone to burrs, it is the most important hidden danger that causes metallization of inferior holes. Must adopt deburring technological method to solve. Usually mechanical means are used to make the hole edge and inner hole wall without barbs or plugging.
2. Degreasing
3. Roughening treatment: mainly to ensure good bonding strength between the metal coating and the substrate.
4. Activation treatment: mainly forms the “initiation center” to make the copper deposition uniform.

Causes of voids in the hole wall plating:
Hole wall plating cavity caused by 1PTH
(1) Copper content, sodium hydroxide and formaldehyde concentration in copper sink
(2) The temperature of the bath
(3) Control of activation solution
(4) Cleaning temperature
(5) The use temperature, concentration and time of the pore modifier
(6) Use temperature, concentration and time of reducing agent
(7) Oscillator and swing

2 Hole wall plating voids caused by pattern transfer
(1) Pre-treatment brush plate
(2) Residual glue at orifice
(3) Pretreatment micro-etching

3 Hole wall plating voids caused by pattern plating
(1) Micro-etching of pattern plating
(2) Tinning (lead tin) has poor dispersion

There are many factors that cause coating voids, the most common is PTH coating voids, which can effectively reduce the generation of PTH coating voids by controlling the relevant process parameters of the potion. However, other factors cannot be ignored. Only through careful observation and understanding of the causes of coating voids and the characteristics of defects can the problems be solved in a timely and effective manner and the quality of the products can be maintained.