Drilling to the Source of Voids

摘要

In april, we began our exploration of PTH voids. This month we discuss many more of their causes. Seasoned engineers often note the many process steps and variables that will influence the success or failure of getting a continuous, void-free copper deposit in the hole. One of the obvious causes of voids, or poor copper coverage at least, is poor drilling. FIGURE 1 shows voids on the glass bundle fibers. A close look at this section reveals a very poorly drilled hole wall, with glass bundles protruding from the resin.