Equipment Design and Control of Advanced Thermal-Processing Module in Lithography

A programmable multizone thermal-processing module is developed to achieve wafer-temperature uniformity during the thermal-cycling process in lithography. The bake and chill steps are conducted sequentially within the same module without any substrate movement. An array of thermoelectric devices (TEDs) is used to provide a distributed heating 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. This design is an improvement of a previous work, eliminating the need of a mica heater. The system is designed via detailed modeling and simulations based on first-principle heat-transfer analysis. Experimental results on the prototype demonstrate about ??0.4??C spatial uniformity during the entire thermal cycle.