PCB etching technology is the use of chemical photosensitive materials photosensitive properties, in the base metal substrate on both sides of the uniform Xu dress photosensitive materials using photolithography methods, will be an adhesive film plate on the grid net production show the shape of an accurate copy of the metal substrate on both sides of the light-sensitive layer mask by the development of the removal of unsensitized portions of the mask, will be exposed to the metal part of the subsequent processing of the corrosive fluid in direct contact with the pressure of the etching solution, and ultimately access to the required geometric Shape and high precision size of the product technology etching technology.
Etching is at a certain temperature under the conditions of etching liquid through the nozzle evenly sprayed to the surface of the copper foil, and no etching resist protection of copper redox reaction, and the unwanted copper reaction off, exposing the substrate and then after stripping treatment to make the line shape. The main components of etching solution: copper chloride, hydrogen peroxide, hydrochloric acid, soft water (solubility has strict requirements)
Etching process flow is: stripping film → circuit etching → stripping Tin lead
PCB etching process quality requirements and control points:
1. There can be no residual copper, especially double-sided board should pay attention to.
2. There can be no residual glue, otherwise it will cause copper or plating adhesion bad.
3. Etching speed should be appropriate, do not allow excessive etching caused by line thinning, etching line width and total pitch should be the focus of control as this site.
4. Line soldering points on the dry film shall not be flushed separation or fracture.
5. Etching stripped film after the plate does not allow oil, impurities, copper skin warping and other poor quality.
6. Release the board should pay attention to avoid card board, prevent oxidation.
7. Should ensure that the etching liquid distribution of uniformity, in order to avoid the front and back or the same side of the different parts of the etching is not uniform.
Line width: etching standard line for .2mm & 0.25mm, its etching shall be within +/-0.02mm.
8. Surface quality: no wrinkles and scratches.
9. No copper residue can be inspected by light transmission.
10. The line must not be deformed
11. No oxidized water droplets
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