Numerical aspects of temperature profile reconstruction using acoustic tomography in RTP

Abstract

Precise wafer temperature control is crucial to the viability of the emerging technology of mpid thermal processing (RTP) for semiconductor manufacturing. In this paper we examine the problem of accurate noninvasive measurement of wafer temperature, which is required for precise tempemture control. Our work extends the work of Khuri-Yakub et al. (1993) on acoustic techniques for noninvasive wafer tempemture measurement. W e propose a method for estimation of wafer temperatures via regularized tomographic inversion using a priori knowledge of properties of the temperature distribution and data obtained by their technique. Results of simulation studies of the methods proposed are described.