In the manufacturing process for making printed circuit boards (PCB) it is necessary to drill holes in the base copper clad laminate. This is a crucial step in the case of multi‐layer boards where the holes must be plated with copper to complete the electrical connection between the layers. Drilling is an expensive process as it requires the use of extremely sophisticated equipment. Most often this resides with a handful of companies; namely board shops and drill bit manufacturers. In recent years, with the evolution of high performance resins such as high glass transition (Tg) and decomposition temperature (Td) as well as low dielectric constant (Dk) and the continued embracement of the use of phenolic cured resins compared to dicyandiamide (DICY), issues around drillability have increased. As a part of our efforts we compared the mechanical and thermo‐mechanical properties of three resins. Actual drilling studies were performed on three‐high, copper clad stacks made from these three resins at Megatool in California, in order to confirm our fundamental property correlations. Resin toughness was found to play a crucial role in the final PCB drillability.
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