Many designs require more than a single lamination cycle. Some require two boards made separately and then bonded together to form the final board. Another is a board with all but one layer, with the final layer bonded after filling the vias of the first. Many newer designs need sequential layers bonded one by one to provide for stacked or staggered microvias.
For many materials, multiple sequential lamination operations cause over cure and degradation of the laminate’s resin. This is not a problem with Arlon’s 85N or 85HP products. Both products are used with as many as six sequential lamination steps without resin degradation issues. 85HP’s unique blend of pure polyimide resin and micro-fine proprietary fillers results in superior performance for demanding applications. Compared to conventional polyimide systems, 85HP has a lower Z-axis expansion and twice the thermal conductivity at .5 W/M/k. 85HP reduces resin cracking and wicking in designs with high density plated through holes and vias. 85HP prepreg has resin flow characteristics and pressed thickness matching standard polyimides. 85HP meets the requirements of IPC-4101E/40, /41 and /43.
85N is a pure polyimide resin system for PWB’s requiring resistance to high temperature with decomposition temperatures greater than 400°C, and glass transitions of 250°C. 85N’s bromine-free chemistry provides Best in-Class thermal stability for applications with sustained high in-use temperatures as well as for use in lead-free soldering applications. 85N meets the requirements of IPC-4101E/40 and /41.