CD uniformity improvement and IC process monitoring by wireless sensor technology

A new wafer-level wireless temperature sensor technology was developed for in-situ etch process performance monitoring and improvement of critical dimension control in litho process. For plasma etch application, the system is shown to be cost-effective, reliable, and easy to implement within any commercially available plasma chambers. In addition, a new level of process insight along with optimization opportunities can be realized from the system´s implementation. For litho application, critical dimension (CD) uniformity control is one of the major challenges for DUV process due to high-temperature sensitivity of 193nm chemically amplified resist in the post-exposure bake (PEB). The PEB step has been traditionally calibrated for optimum across hot plate temperature uniformity at static, steady state by utilizing wired temperature sensor technology. For sub-100nm technology nodes, however, current method is insufficient for tightening CD control. A real time monitor and full thermo-profile study is needed instead. In this paper the new wireless temperature sensor metrology is demonstrated to achieve both temperature uniformity and CD uniformity improvement.