PCB Blog - PCB Board Manufacturing Defect Solutions

There are many processes involved in the manufacturing process of PCB board, and quality defects may occur in each process. These qualities always involve many aspects, which are more troublesome to solve. The reasons for the problems are many, and some are chemical, machinery, sheet metal, optics, and so on. After decades of production practice, combined with practical experience in solving quality problems and relevant information on solving technical problems, the defects, causes, and solutions in the printed circuit board manufacturing process are summarized as follows:

Film: there are bubbles in the film layer of the board, and the board surface is not clean, check the wettability of the board surface, that is, a clean surface can keep the water uniform, and the continuous water film time is up to 1 minute

Film temperature and pressure too low Increase temperature and pressure

The edge of the film is lifted: the adhesion of the film is poor due to the excessive tension of the film; adjust the pressure screw

Film crepe: poor contact between the film and the board surface; tighten the pressure screw

Exposure: poor resolution, due to scattered light and reflected light reaching the cover of the film; reduce exposure time

Overexposure; reduce exposure time

Image yin-yang difference; sensitivity too low makes the yin-yang difference ratio 3:1

Poor contact between the film and the board surface Check the vacuum system

Insufficient light intensity after adjustment Adjust again

Overheating Check the cooling system

Intermittent exposure Continuous exposure

Dry film storage conditions are poor Works under yellow light

Development: There is scum in the development area. Insufficient development, resulting in a colorless film remaining on the board. Slow down and increase the development time.

The developer composition is too low Adjust the content to 1.5-2% sodium carbonate

Too much film in the developer solution Replace

The development and cleaning interval is too long and should not exceed 10 minutes

Insufficient developer injection pressure Clean the filter and check the nozzle

Overexposure Correction of exposure time

Improper sensitivity and the ratio of the sensitivity should not be less than 3

The film is discolored and the surface is not bright Insufficient exposure, resulting in insufficient film polymerization Increase the exposure and drying time

Excessive development Reduce the development time, correct the temperature and cooling system, and check the developer content

The film falls off the board The film does not adhere well due to underexposure or overdevelopment Increase exposure time, decrease development time, and leveling content

Dirty surface Check surface wettability

After the film is exposed, go to development immediately After the film is exposed, stay for at least 15 to 30 minutes

There is excess glue on the circuit pattern Dry film expired Replace

Underexposure Increase exposure time

The surface of the film is not clean Check the quality of the film

Improper developer composition Adjust

Development speed is too fast Make adjustments on the PCB board.