Press Cycle for Multilayer Bonding

The actual press cycle is of utmost importance for the manufacture of multilayer printed circuit boards. It is necessary for both the engineers and the operators to understand its factors of influence in order to gain the highest production yields. This paper describes the differences between single‐stage and two‐stage press cycle, cold start and hot start, and also the difference between bonding of multilayers in a hydraulic press vs. in a vacuum autoclave. Detailed insight is given into what is actually happening during the press cycle and how it can be influenced. Special recommendations for bonding of no‐flow prepregs and of multilayers with buried via‐holes or metal cores are given in a separate chapter.