POLISHING PITS

摘要

Pitting or localized damage is observed both in oxide and silicon polishing. It seriously reduces the useful pad life and damages the wafers. The mechanism is not fully understood. Once attacked, the wafers cannot be reworked, resulting in scrap. The polishing pad plays a dominant role as the pitting attack is observed either with a new pad or a pad that has seen about 100 runs. The pits have smooth edges and occur only in certain areas of the wafer. Unless resolved, pitting can result in loss of manufacturing time and material.