What problems often occur in the use of PCB?

1. Degreasing (temperature 60-65℃)
(1), there are many bubbles: abnormal quality caused by more bubbles: it will lead to poor degreasing effect, reason: caused by mismatched tank liquid.
(2). Particulate matter composition: Particulate matter composition Cause: The filter is broken or the high-pressure water washing of the grinder is insufficient, and the outside brings dust.
(3) Fingerprint degreasing will not fall off: Fingerprint degreasing will not fall off Cause: Degreasing temperature bottom, mismatched syrup.
2. Micro-etching (NPS 80-120G/L H2SO4 5% temperature 25-35℃)
(1). The copper surface of the board is slightly white: the reason is the grinding of the board, insufficient oil removal or pollution, and the concentration of the medicine is low.
(2) The copper surface of the board is black: after degreasing, the water is not cleaned and is contaminated by degreasing. The pink surface of copper is the normal effect of micro-etching.
3. Activation (the color of the bath liquid is black, the temperature should not exceed 38℃, and it cannot be pumped up)
(1) Precipitation and clarification of the bath liquid:
Reasons for precipitation in the bath:
① The concentration of supplemented with water immediately changes, and the content is low (the normal supplementary liquid level should be prepreg)
②Sn2+ concentration is low, Cl- content is low, and the temperature is too high.
③Contaminated by Fe+.
(2) A silver-white film appears on the surface of the potion:
A silver-white film appeared on the surface of the potion. The cause: oxides produced by Pd oxidation.
4. Speed up (processing time 1-2 minutes temperature 60-65℃)
(1). The hole has no copper: Cause: The acceleration treatment time is too long, and Pd is removed at the same time as Sn is removed.
(2) High temperature Pd is easy to fall off.
5. The chemical liquid in the chemical copper cylinder is contaminated
Reasons for the contamination of the chemical liquid: (1), insufficient water washing before PTH (2), Pd water brought into the copper cylinder (3), there is a board to drop the cylinder (4), long-term no explosion cylinder (5), insufficient filtration
Cylinder washing: Soak in 10% H2SO4 for 4 hours, then neutralize with 10% NAOH, and finally clean with water.
6. The hole wall cannot sink on copper
Reasons: (1), poor degreasing effect (2), insufficient slag removal (3), excessive slag removal
7. The hole copper is separated from the hole wall after thermal shock
Reasons: (1), bad slag removal (2), poor water absorption of the substrate
8. Strips of water ripples on the surface
Reasons: (1), irrational design of the hanger (2), excessive stirring in the copper sink (3), insufficient washing after acceleration
9. Temperature of chemical copper liquid
Excessive temperature will cause the chemical copper solution to decompose quickly, and the composition of the solution will change to affect the quality of the electroless copper plating. High temperature will also produce a lot of copper powder, causing copper particles in the board surface and holes. Generally controlled at about 25-35℃.