Opening cover foils on copper-laminated circuit boards

The sealing of conductor lines on flexible or rigid circuit boards with cover foils serves as a long-term protection against corrosive environmental conditions as well as a solder-resist mask. Cover foils are one-sided adhesive films, e.g. based on polyimide. The solder regions or orifices are manufactured mechanically before the coating process, i.e. drilled or punched out. However, using mechanical techniques it is not possible to create the finest openings in the cover foils. In addition, the accuracy of film positioning on the base material is also no longer adequate in this case.

Laser processing is based on the principle of ablating the cover foil material in the area of the desired opening. Because of the fineness and precision of the laser beam, it is possible to create ultra-fine openings with extremely high position accuracy and precision. Furthermore in case of small batches the costs for the punching tool can be avoided.


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