Hole metallization process of circuit board
The hole metallization process is one of the most critical processes in the manufacture of printed circuit boards. For this reason, it is necessary to carefully check the copper surface of the substrate and the state of the inner surface of the hole.
(1) Inspection project
1. Is the surface condition good? No scratches, no indentations, no pinholes, no oil, etc.;
2. Check the inner surface of the hole to maintain a uniform and slightly rough, no burr, no screw, no chip residue, etc.;
3. Chemical analysis of the copper bath to determine the amount of supplement;
4. Circulating the chemical copper solution to maintain the uniformity of the chemical composition of the solution;
5. Monitor the temperature inside the solution at any time and keep it within the process range.
(2) Quality control of hole metallization
1. Determine the quality and process parameters of the copper bath and control the range and make a record;
2. Monitoring and treatment quality status analysis of the pretreatment solution before perforation;
3. To ensure the high quality of the copper sink, it is recommended to use a stirring (vibration) plus cycle filtration process;
4. Strictly control the monitoring of process parameters of chemical copper sinking process (including PH, temperature, time, main components of the solution);
5. Using the backlight test process method, refer to the light transmission degree image (divided into 10 levels) to determine the copper effect and the quality of the copper layer;
6. After thickening copper plating, the metallographic sectioning test should be carried out according to the process requirements.
Section III Hole Metallization
The metallization process is one of the most important processes in printed circuit board manufacturing technology. The most commonly used method is the thick copper process. Here’s how to control it, there are several aspects:
1. The most effective method of sinking copper is to use hanging orchids and tilting 300 angles, and there must be a certain distance between the substrates.
2. To maintain the cleanliness of the solution, it must be filtered;
3. Strictly control the temperature of the solution which has a great influence on the quality of the copper. It is best to use a water jacket cooling system;
4. The cleaned substrate must be immediately dried with hot air.