Mechanisms underlying temperature uniformity in electrostatic chucks through experimental and simulation methods

Abstract

Electrostatic chucks (ESCs) play a crucial role in securing and holding wafers during processing or testing in the semiconductor industry. ESCs are favored for their superior clamping performance, ensuring high-quality and consistent semiconductor products. Nevertheless, the temperature uniformity in ESCs is paramount to achieving these goals. In this study, the surface temperature distribution of a 12-inch four-zone ESC was investigated based on thermodynamics and hydromechanics theories. A numerical model has been constructed and validated via relevant experiments. Both results show that the surface temperature uniformity of the ESC can be improved by appropriately increasing the coolant flow rate. The impact of the distance from cooling channel to the pedestal and the height of cooling channel on the temperature uniformity of the ESC was studied particularly. The findings indicate that an extended distance yields a heightened surface temperature while simultaneously reducing temperature differences. Moreover, increasing the height leads to a reduction in ESC surface temperature but degradation in temperature uniformity. This work has the potential to significantly reduce experimental costs, enhance equipment reliability and provide valuable insights for investigating temperature uniformity mechanisms in ESCs, as well as for modeling and designing such systems.