The pattern transfer process is a pivotal step in the manufacturing of printed circuit boards (PCBs). Traditionally, dry film technology was utilized for this purpose, but the current trend primarily involves the use of wet film for inner layer circuit patterns in multilayer PCBs and for outer layer circuit patterns in double-sided and multi-layer boards.
Crafting Process:
- Pretreatment
- Screen printing
- Baking
- Exposure
- Development
- Anti-plating or anti-corrosion
- Film removal
- Subsequent processes
Key Process Analysis: - Selection of Coating Method
- Screen printing method is generally preferred due to its suitability for PCB production.
- Pretreatment
- Chemical and mechanical cleaning to ensure proper bonding with the wet film.
- Control of Viscosity and Thickness
- Calculation of wet film thickness, considering factors such as aperture area and ink solid content.
- Importance of maintaining optimal thickness for specific applications (anti-corrosion or anti-electroplating) to meet resistance and insulation requirements.
Conclusion:
Understanding the wet film coating method and its application in PCB pattern transfer is essential for ensuring the quality and functionality of printed circuit boards in the current manufacturing landscape. By carefully considering the selection of coating method, pretreatment processes, and control of viscosity and thickness, manufacturers can optimize the pattern transfer process to meet the specific requirements of PCB production.
