Thermal design of hot plate for 300-mm wafer heating in post-exposure bake

Temperature uniformity of a wafer during post-exposure bake (PEB) in lithography is an important factor in controlling critical dimension (CD) uniformity. In this study, a new hot plate system for the PEB of a 300-mm wafer was analyzed and designed. First, temperature deviation on the wafer caused by warpage was investigated, and the heater pattern of the multi-zone hot plate in the bake system was numerically analyzed. Then, a new heater pattern to enhance the temperature uniformity was proposed and tested experimentally. As a result, temperature uniformity within 0.087 °C on a 300-mm wafer was achieved.