Uniformity characterization of an RTP system

Abstract

The use of rapid thermal processing (RTP) is expanding greatly in semiconductor processing. As demands on equipment become greater, the need to characterize system performance also increases. One aspect of RTP equipment performance which has proven difficult to measure is the temperature uniformity of the wafer during processing. Several methods of direct temperature measurement are described: high speed calorimetry to measure the incident power distribution, multiple thermocouple, and scanning pyrometer measurements for directly measuring local wafer temperatures. Indirect techniques which are more applicable to end user characterization are also discussed: measurement of sheet resistance across a wafer implanted with a uniform high dose of arsenic ions and thickness uniformity of thin silicon oxides grown by rapid thermal oxidation. Finally, the use of melt uniformity and slip generation as qualitative indicators of uniformity is discussed. Examples of measurements and their use in the adjustment of a commercial system (Eaton ROA-400) are given. © 1987.