Precautions in the etching process

Reduce side corrosion and protruding edges, and improve the metal etching processing coefficient: Generally, the longer the printed board is in the metal etching solution, the more serious the side etching. Undercuts seriously affect the accuracy of printed lines, and severe undercuts will not be able to make thin lines. The etch factor increases as undercuts and edges decrease. A high etch factor indicates the ability to maintain fine lines and etch lines close to the size of the original image. Whether the plating resist is tin-lead, tin, tin-nickel, or nickel, etc., excessively protruding edges can cause wire shorts. Since the protruding edge is easily broken, a bridge is formed between the two points of the wire.

Improve the consistency of etching process rate from plate to plate: In continuous plate etching, the more consistent the metal etching process rate is, the more uniform an etched plate can be obtained. In order to always maintain the best etching state during the pre-etching process, it is necessary to choose an etching solution that is easy to regenerate and compensate, and the etching rate is easy to control. Select technologies and equipment that provide constant operating conditions and automatically control various solution parameters. It can be realized by controlling the amount of dissolved copper, PH value, solution concentration, temperature, and uniformity of solution flow.

Improve the uniformity of metal etching processing speed on the entire board surface: The etching uniformity of the upper and lower sides of the board and each part of the board surface is determined by the uniformity of the flow rate of the metal etching solution on the board surface. During the etching process, the etching rates of the upper and lower plates are often inconsistent. The etch rate of the lower surface is higher than that of the upper surface. The etching reaction is weakened due to the accumulation of the solution on the surface of the upper plate. The uneven etching of the upper and lower plates can be solved by adjusting the injection pressure of the upper and lower nozzles. Using a spray system, oscillating the nozzle, can further improve the uniformity of the entire surface of the board by making the spray pressure at the center and edge of the board different.