Common trouble shooting for dry film process

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One, copper or tin plating lead infiltration

Cause solution

1, dry film performance is poor, over the expiry date of use. Use dry film as long as possible.

2, substrate cleaning is not clean or coarse surface is not good, dry film adhesion is not firm. Strengthen board surface treatment.

4, exposure too brittle resist. Calibration of exposure amount or exposure time with optical densitometry.

5, insufficient exposure or overdevelopment caused by corrosion inhibitor hair, too warping. Adjust exposure, developing temperature and developing speed.

6, electroplating pretreatment liquid temperature is too high. Control the temperature of various pretreatment solutions before plating.

Bubbles appear between the dry film and the surface of copper foil

Cause solution

1, the film temperature is too high, the volatile components in the resist volatile rapidly, residual in the polyester film and copper clad foil between the formation of bubbling. Adjust the film temperature to the standard range.

2, hot roller surface uneven pits or scratches. Pay attention to protect the smooth surface of the hot pressing roller, and do not use hard and sharp tools to clean the hot pressing roller.

3, the pressure of the roller is too small. Increase the pressure of two pressure rollers appropriately.

4, the board surface uneven scratches or pits. Select the plate and pay attention to the previous process to reduce the possibility of scratches and pits.

Third, the dry film image is fuzzy after development, and the resist is dark and hairy

Cause solution

1. Insufficient exposure. Calibrate the amount of light or exposure time with an optical densimeter

2, the minimum optical density of the photographic plate is too large, so that ultraviolet light is blocked. Check photographic plate before exposure.

5, the developer temperature is too high or the development time is too long. Adjust the transfer speed of developer shedding and developing

Four, excess glue

Cause solution

1, dry film quality is poor, such as high molecular weight or coating dry replacement dry film. Membrane process accidental thermal polymerization and so on.

2, dry film exposed to white light caused partial polymerization. Dry film operation under yellow light.

3. The exposure time is too long. Shorten exposure time.

4, photographic background Max optical density is not enough, resulting in ultraviolet light through, partial polymerization. Check photographic plate before exposure.

5, exposure photographic substrate and poor contact caused by virtual light. Check vacuum system and exposure frame.

6. Developer temperature is too low, developing time is too short, spraying pressure is not enough or part of the nozzle is blocked. Adjust the developer temperature and development of the transfer speed, check the development equipment

7, the developer produces a large number of bubbles, reducing the spray pressure. Add an antifoaming agent to the developer to remove foam.

8. Developer failure. Replace the developer.

Five, dry film wrinkling

Cause solution

1. The axial direction of the two hot pressing rollers is not parallel, so that the dry film is pressed unevenly. Adjust the two hot rollers so that they are axially parallel.

2, dry film is too sticky. Skilled operation, more careful when putting the board.

3, the film temperature is too high. Adjust the film temperature to the normal range.

4. The plate before the film is too hot. The board preheating temperature should not be too high.