Transferring polymer from thin plastic films to photodevelop insulation patterns on printed wiring boards

摘要

Printed wiring boards have a first liquid photopolymer layer placed on the wiring board conductive layer over which a second photopolymer layer is laminated and both layers are photo cured in place to bond the two layers together and adhere them to the board. The liquid photopolymer layer covers wiring pattern ridges or other uneven surfaces in air free surface contact. The second layer is carried by a thin transparent plastic film for lamination onto the first photopolymer layer by a squeegee, and the plastic film is peeled off for reuse in further cycles. The carrying film is preferably pivotable in a clamshell arrangement to permit the photopolymer layer to be placed on the film and then to be laminated in two pivot positions. To prevent starvation of the liquid polymer from wiring ridges when the second layer is laminated thereon, the second layer is carried on a contoured surface with a complementary pattern to the wiring ridge pattern.