A Noninvasive Temperature Sensor for Plasma Processing of Semiconductors

本文提出了一种用于电子材料干刻蚀（等离子体刻蚀、反应离子刻蚀等）的非侵入式温度传感器的研究方案。目前迫切需要这种传感器，因为水的温度会影响蚀刻过程的结果；蚀刻速率，下切和表面质量。此外，用于遮盖的光刻胶在高温下开始烧焦。因此，随时测量和监测晶圆片温度是很重要的。提出的努力将导致一种新的温度传感器测量和监测晶圆温度在干蚀刻环境。这里的创新之处在于，所提出的技术将使在等离子蚀刻室中进行表面温度测量的非侵入性，非接触式和非破坏性方法成为可能。相比之下，现有的技术是侵入性的和繁琐的，需要接触排除了测量过程晶圆温度；目前只测量阴极或假晶圆的温度。提出的研究是研究光反射率作为上述目的的温度传感器。半导体材料的能隙将用调制光谱测量，并与表面温度相关。第一阶段的工作证明了该技术的可行性和准确性。第二阶段的努力将产生一个原型仪器，并展示其在工业环境中改善实际蚀刻的用途。

This proposal outlines a research program to develop a non-invasive temperature sensor for application in dry etching (plasma etching, reactive ion etching for example) of electronic materials. There is a critical need for such sensors at present since the temperature of the water influences the results of the etching process; etch rate, undercutting, and surface quality. In addition, the photoresist used for masking begins to char at elevated temperatures. Hence, it is important to measure and monitor the wafer temperature at all times. The proposed effort would result in a novel temperature sensor to measure and monitor wafer temperature in dry etching environment. The innovation here is that the proposed technique would enable a non-invasive, contactless and non-destructive method of performing surface temperature measurement in a plasma etching chamber. In contrast, existing techniques are invasive and cumbersome and the need for contacting precludes measuring the process-wafer temperature; instead only the temperature of the cathode or a dummy wafer is measured at present. The proposed research is to investigate photoreflectance as a temperature sensor for the above purpose. The energy gap of the semiconductor material would be measured using modulation spectroscopy and correlated to the surface temperature. The Phase I effort demonstrate the feasibility and accuracy of this technique. The Phase II effort would result in a prototype instrument and demonstrate its use in improving practical etching in an industrial environment.