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MARTIN L. SPARTZ, MATTHEW RICHTER, PETER A. ROSENTHAL & PETER R. SOLOMON,
On-Line Technologies, Inc., East Hartford, CT, USA

ABSTRACT

Gases utilised and generated during semiconductor fabrication can be monitored in real-time by infrared spectroscopy to determine the wafer state information during semiconductor manufacturing. Whereas methods based on quadrupole mass spectroscopy (QMS) residual gas analysis (RGA) tend, at best, to produce relative quantitative results, infrared spectroscopy can provide absolute quantitative gas chemistry data. Gas chemistry changes are excellent diagnostics of processing variations or errors such as first wafer effects, chamber temperature effects, improperly chucked wafers, variation in plasma power, system leaks, and variation in gas flows from mass flow controllers. Tight process control of wafer etching and chamber cleans can be obtained through gas composition knowledge. This knowledge can be used to control consumption of perfluorocompounds (PFCs) during chamber cleans and wafer etch processes. The On-Line Technologies INDUCT™ system is an FTIR based inline monitoring system. It was designed for placement between the turbo and roughing pumps for in-situ real-time monitoring of the gas chemistry. A system such as this provides significant gas composition knowledge that can be used for fault detection and classification, endpoint determination and reduction in PFC usage.