Measurement Bias Detection, Identification and Elimination for Multi-Zone Thermal Processing in Semiconductor Manufacturing

Temperature uniformity within wafer and from wafer to wafer are important issues with stringent specifications and significant impact on the smallest feature size or critical dimension. To obtain temperature uniformity, a wafer is heated by multiple independently controlled heating elements simultaneously. The accuracy of temperature measurement is an issue. Faults include sensor bias, complete failure, drifting, precision degradation etc. In this paper, we demonstrate the detection of gross errors and the elimination of biased reading in a multi-zone thermal system for semiconductor wafer processing.