マイクロ温度センサを用いたIn-Situウェハ温度計測制御 : 第2報,MEMS技術を応用したセンサの試作(機械力学,計測,自動制御)

Abstract

The precise in-situ measurement of wafer temperature has not been achieved in the semiconductor processes of 200[℃] or less such as photolithography and dry etching. The post exposure bake (PEB) sensitivity is well known as one of the main factors to critical dimension (CD) non-uniformity in photolithography. For that reason, we proposed an in-situ measurement and control method of wafer temperature based on micro area contact to a processing wafer using some micro sensors. The 1st report showed the effectiveness of the proposed method, in-situ measurement accuracy 0.1[℃] etc. from experimental results using a large model of the micro sensor. This paper shows the fabrication of 650×650×280[μm^3] sensor chip based on MEMS technology and its characteristics. The process flow of the fabrication consists of thermal insulation structure formulation using permanent photoresist, half cut dicing and polishing of Si substrate to 10[μm] or less in thickness, through-vias formulation into thermal insulation structure using Ag nano paste, and so on. The measurement accuracy of the sensor chip is 0.03[℃], and it is high enough as a resistance temperature detector. In addition, the mounting method of the micro sensor in a plate surface using the nanomembrane of 200[nm] in thickness is proposed for the purpose of its protection against cleaning of the plate surface at maintenance, suppression of particle generation from it, and so on. The proposed mounting method will be able to improve resistance to trouble without degradation of in-situ measurement accuracy.