1、 Quality requirements and key control points for PCB etching process:

　　1. There should be no residual copper in the sample production of PCB boards, especially double-sided boards, which should be noted.

　　2. There must be no residual adhesive present, otherwise it will result in exposed copper or poor adhesion of the coating.

　　3. The etching speed should be appropriate, and it is not allowed to show the thinning of the line caused by excessive etching. The etching line width and total pitch should be the focus of our station's control.

　　4. The dry film on the solder joints of the circuit shall not be washed away or cracked.

　　5. After etching and peeling, the board should not have any oil stains, impurities, copper skin warping or other poor quality.

　　6. When placing the board, attention should be paid to preventing jamming and oxidation.

　　7. It should be ensured that the etching solution is evenly distributed to prevent uneven etching of different parts on the front and back or the same surface.

　　2、 PCB etching process control parameters:

　　Etching solution temperature: 45+/-5 ℃ Hydrogen peroxide solubility: 1.95~2.05mol/L

　　Stripping solution temperature: 55+/-5 ℃ Etching machine safe operating temperature ≤ 55 ℃

　　Drying temperature: 75+/-5 ℃, distance between front and rear plates: 5-10cm

　　Specific gravity of copper chloride solution: 1.2-1.3g/cm3, plate angle, guide plate, and switch status of upper and lower nozzles

　　Hydrochloric acid solubility: 1.9~2.05mol/L