A heater plate assisted bake/chill system for photoresist processing in photolithography

Abstract

A thermal processing module, which consists of a dense distribution of multivariate controlled heat/chill elements, is developed to achieve temperature uniformity of a silicon wafer throughout the processing temperature cycle of ramp, hold and quench in microlithography. In the proposed unit, the bake and chill steps are conducted sequentially within the same module without any substrate movement. The unit includes two heating sources. The first is a mica heater which serves as the dominant means for heat transfer. The second is a set of thermoelectric devices (TEDs) which are used to provide a distributed amount of heat to the substrate for uniformity and transient temperature control. The TEDs also provide active cooling for chilling the substrate to a temperature suitable for subsequent processing steps. The feasibility of a practical system is demonstrated via detailed modeling and simulations based on first principle heat transfer analysis. © 2008 Elsevier Ltd. All rights reserved.