Insertion Error in LPRT Temperature Measurements

Accurate measurement of surface temperature distribution is of great concern in the semiconductor industries, particularly in rapid thermal processing (RTP). The International Technology Roadmap for Semiconductors 2004 (ITRS) has established requirements of uncertainties of plusmn1.5 degC at temperature of 1000 degC, with temperature calibration traceable to ITS-90 (International Temperature Scale-1990). Light-pipe radiation thermometers (LPRTs) are becoming increasingly important as an industrial tool for temperature measurement, especially in the semiconductor industry. However, there are several radiation issues associate with LPRTs, and without fully understanding them, achieving further accuracy could be hobbled. In this paper, we concentrate on the insertion error in the LPRTs temperature measurement. The "drawdown effect" and "shadow effect" are investigated. The "drawdown effect" is caused by the physical mass of the light-pipe probe acting as a heat sink for the measured object and the "shadow effect" is caused by distortion of radiosity due to the presence of the light-pipe probe. Monte Carlo simulation was conducted and compared to the experiment results