Rigid/flexible circuits Manufacturing process

There are many varieties of manufacturing processes for multilayer rigid/flexible circuits because of their complicated structures. Figures 65.5 shows a typical layer construction using... 

Furthermore, the overall properties of the base materials for circuit boards are determined essentially by the joint between the copper foil and the laminate. This joint can be realized by both an added adhesive and by the laminating resin itself, which additionally, acts as adhesive. An additional adhesive is needed in the manufacture of flexible circuit boards (e.g., polyimide/copper) or of paper-based rigid circuit boards. During this process the adhesive is deposited on the bottom side of the copper foil after... 

Figure 63.2 shows standard manufacturing processes of the through holes for the doublesided flexible circuits. A mechanical numerically controlled (NC) drilling process on double-sided flexible circuits can be done similarly to that used for rigid double-sided printed circuit boards. More laminates can be stacked up in the setup because of the thin materials. 

Because of thin base layers, the flexible circuits can have many sjrecial constructions that are impossible to build by traditional manufacturing processes of the rigid circuit boards. These special constructions generate further functional values for the flexible circuits. This chapter introduces the major constructions in use, along with their manufacturing processes. 

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