At present, the printed circuit board (PCB) processing of the typical process using "graphics plating." That is, the first part of the copper foil to be retained in the outer layer of the board, that is, the graphics part of the circuit pre-plated layer of tin-lead layer, and then chemical corrosion of the remaining copper foil, known as etching. It should be noted that there are two layers of copper on top of the board, and only one layer of copper must be etched away in the outer etch process, and the rest will be the final required circuit. This type of pattern plating is characterized in that the copper plating layer is present only under the lead-tin resist layer. Another process is the entire board are copper, the photosensitive film is only part of the tin or tin-lead resist (see Figure 3). This process is called "full-plate copper plating process". Compared with the pattern of plating, the whole board is the biggest drawback of copper plating all parts of the board should be plated twice and etched when they have to be etched away. So when the wire width is very fine will produce a series of problems. At the same time, lateral corrosion (see Figure 4) will seriously affect the uniformity of the line.
Etching Process Of PCB External Circuit
- Jan 16, 2017 -