Pressing is one of the important processes in the production of printed circuit board(PCB).This article tests the cushioning properties of different cushioning materials,and comparatively analyzes the effects of different stacking structures on board thickness,uniformity expansion/contraction ratio,reliability,and resin filling.Research results show that the PacoPads cushioning material laminate performs uniformity the best in terms of board thickness uniformity and expansion/contraction ratio,for a high multi-layer PCB with board thickness of 3 mm,the board thickness range can be within 0.2 mm,and the expansion/contraction can be within 0.04 mm;the aluminum sheet+three-in-one cushioning material laminated performs the best in terms of resin filling,and can achieve effective filling of 0.8 mm pitch ball grid array(BGA)and 50 mm×50 mm copper-free area.This article can provide reference for solving problems such as board thickness uniformity and resin-starving in high multi-layer PCB.
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