What should be paid attention to in the anti-corrosion treatment of multilayer circuit boards:
If the line drawing lineweight is within 30 μ If the figure is formed with dry film below m, the qualified rate will be significantly reduced. In mass production, liquid photoresist is generally used instead of dry film. The coating thickness will change with different coating conditions. If the coating thickness is 5 ~ 15 μ M of liquid photoresist at 5 μ On m-thick copper foil, the laboratory level can etch 1o μ Line width below M.
The liquid photoresist must be dried and baked after coating. Because this heat treatment will have a great impact on the performance of the resist film, the drying conditions must be strictly controlled.
Formation of conductive pattern - double sided FPC manufacturing process
Photosensitive method is to use UV exposure machine to make the resist layer coated on the surface of copper foil form line pattern.
In the previous sections, some related FPC technologies for making double-sided FPC are introduced In this section, we will introduce the formation of conductive patterns in FPC fabrication
Photosensitive method is to use UV exposure machine to make the resist layer previously coated on the surface of copper foil form FPC circuit pattern. If a single FPC is used for exposure, the equipment is the same as that used for rigid printed boards, but the fixture for coincident positioning is different. The special graphic mask positioning fixture for FPC of flexible printed board is available on the market. However, many FPC manufacturers are made alone, which is very convenient to use. The positioning pin is used for positioning. Due to the shrinkage deformation of FPC of flexible printed board, it is generally resistant to the spray pressure of developer. Therefore, the structure of the nozzle, the arrangement and pitch of the nozzle, the direction and pressure of the injection are very key. As the developer is recycled, it will change gradually, so the developer should be inspected and analyzed frequently and updated regularly with appropriate frequency according to the analysis results.
