Two-bandpass fiber-optic radiometry for monitoring the temperature of photoresist during dry processing

The temperature of a thin photoresist layer on a silicon wafer was measured in situ during dry etching by using a silver halide optical fiber noncontact thermometer. A two-bandpass radiometer was constructed to reduce errors arising from geometrical factors and emissivity changes. Such a system may be used to monitor surface temperatures during dry processing of semiconductors and to prevent overheating that may cause damage, such as cross linking of photoresists.