Paper
29 April 2004 Comparing the transient response of a resistive-type sensor with a thin film thermocouple during the post-exposure bake process
Kenneth G. Kreider, David P. DeWitt, Joel B. Fowler, James E. Proctor, William A. Kimes, Dean C. Ripple, Benjamin K. Tsai
Author Affiliations +
Abstract
Recent studies on dynamic temperature profiling and lithographic performance modeling of the post-exposure bake (PEB) process have demonstrated that the rate of heating and cooling may have an important influence on resist lithographic response. Measuring the transient surface temperature during the heating or cooling process with such accuracy can only be assured if the sensors embedded in or attached to the test wafer do not affect the temperature distribution in the bare wafer. In this paper we report on an experimental and analytical study to compare the transient response of embedded platinum resistance thermometer (PRT) sensors with surface-deposited, thin-film thermocouples (TFTC). The TFTCs on silicon wafers have been developed at NIST to measure wafer temperatures in other semiconductor thermal processes. Experiments are performed on a test bed built from a commercial, fab-qualified module with hot and chill plates using wafers that have been instrumented with calibrated type-E (NiCr/CuNi) TFTCs and commercial PRTs. Time constants were determined from an energy-balance analysis fitting the temperature-time derivative to the wafer temperature during the heating and cooling processes. The time constants for instrumented wafers ranged from 4.6 s to 5.1 s on heating for both the TFTC and PRT sensors, with an average difference less than 0.1 s between the TFTCs and PRTs and slightly greater differences on cooling.
© (2004) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Kenneth G. Kreider, David P. DeWitt, Joel B. Fowler, James E. Proctor, William A. Kimes, Dean C. Ripple, and Benjamin K. Tsai "Comparing the transient response of a resistive-type sensor with a thin film thermocouple during the post-exposure bake process", Proc. SPIE 5378, Data Analysis and Modeling for Process Control, (29 April 2004); https://doi.org/10.1117/12.535522
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KEYWORDS
Semiconducting wafers

Sensors

Thin films

Temperature metrology

Resistance

Lithography

Silicon

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