As aPCB Finish Service Supplier, share with you. There are many processes involved in the PCB board manufacturing process, and each process may have quality defects. These quality always involve many aspects, which is more troublesome to solve. Because the causes of problems are many, some are chemical and mechanical. Plates, optics, etc. After decades of production practice, combined with the actual experience in solving quality and the corresponding information related to solving technical problems, it is summarized as follows:

Defects, causes and solutions in the manufacturing process of printed circuit boards

Process Defects Cause Solution

Film: There are bubbles in the film layer of the board The board is not clean Check the wettability of the board, that is, the clean surface can maintain the water evenly, and the continuous water film can last up to 1 minute

The film temperature and pressure are too low: increase the temperature and pressure

The edge of the film is uplifted: The film has too much tension, resulting in poor film adhesion. Adjust the pressure screw

Film shrinkage: Poor contact between the film and the board. Tighten the pressure screw

Exposure: Poor resolution due to scattered light and reflected light reaching the area covered by the film, reducing exposure time

Overexposure: Reduce exposure time

Image yin and yang difference; sensitivity is too low so that the minimum yin and yang difference ratio is 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

Poor storage conditions for dry film: work under yellow light

Development: There is scum on the development area. Insufficient development, causing the colorless film to remain on the board surface. Decelerate and increase development time

The developer composition is too low: adjust the content to reach 1.5-2% sodium carbonate

The developer contains too much film: replace

The interval between development and cleaning is too long: no more than 10 minutes

Insufficient developer jet pressure Clean the filter and check the nozzle

Overexposure: Correct the exposure time

Improper sensitivity: The ratio of maximum to minimum sensitivity should not be less than 3

The film is discolored and the surface is not bright. Insufficient exposure, resulting in insufficient polymerization of the film. 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 layer falls off the board surface: Due to insufficient exposure or overdevelopment, the film layer is not firmly attached. Increase the exposure time, reduce the development time and correct the content

The surface is not clean: check the wettability of the surface

After the film is exposed, it will be developed immediately. After the film is exposed, it will stay for at least 15-30 minutes

There is excess glue on the circuit pattern The dry film expires Replace it

Underexposure: Increase exposure time

The surface of the film is not clean: check the quality of the film

Improper developer composition: make adjustments

Development speed is too fast: make adjustments

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