Method for forming a layer of uniform thickness on a semiconductor wafer during rapid thermal processing

摘要

A ring is provided on a monocrystalline silicon wafer at one face thereof and adjacent the edge thereof. The ring increases the optical absorptivity of the wafer adjacent the ring compared to the optical absorptivity of the wafer distant from the ring. The ring therefore at least partially compensates for edge cooling of the wafer during rapid thermal processing thereof. Uniform thickness layers can therefore be deposited on a wafer in a rapid thermal processing system. When depositing polycrystalline silicon on an oxide covered layer, the ring may be formed as a circular trench in the oxide layer adjacent the wafer edge.