PROCESS MONITORING AND CONTROL DURING PLASMA PROCESSING OF SEMICONDUCTORS

SUCCESSFUL PLASMA PROCESSING AND THE ELUCIDATION OF THE UNKNOWN PLASMACHEMISTRY REQUIRE SIMULTANEOUS KNOWLEDGE OF MANY PROCESS VARIABLES WITHIN THE PLASMA REACTOR. THESE VARIABLES INCLUDE 1) GAS TEMPERATURE AND COMPOSITION, 2) SUBSTRATE TEMPERATURE, AND 3) FILM THICKNESS, COMPOSITION, AND INDEX OF REFRACTION. THERE ARE CURRENTLY NO TECHNIQUES THAT CAN MONIOTR MORE THAN ONE OF THESE VARIABLES AT A TIME. THIS PROPOSAL WILL APPLY FOURIER TRANSFORM INFRARED (FT-IR) SPECTRASCOPY FOR PROCESS MONITORING AND CONTROL OF PLASMA PROCESSING. FT-IR SPECTROSCOPY HAS THE POTENTIAL TO MONITOR MOST OF THE ABOVE PROCESS VARIABLES SIMULTANEOUSLY AND IN-SITU. GOOD SPATIAL RESOLUTIONIS ALSO POSSIBLE. PHASE I WILL DEVELOP MODIFICATIONS OF STATE-OF-THE-ART FT-IR TECHNIQUES AND DEMOSNTRATE THEIR CAPABILITIES BY ESTABLISHING PROCESS CONTROL OF A SIMPLE PLASMA REACTOR. A KEY FEATURE FO THIS PROPOSAL IS THE USE OF IR FIBER OPTICS TO MULTIPLEX THE FT-IR TO MANY SENSING POINTS. IN ADDITION, AFR WILL HOLD TECHNICAL DISCUSSIONS WITH REPRESENTATIVES OF THE MICROELECTRONICS MANUFACTURING SCIENCE AND TECHNOLOGY PROGRAM (MMST). PHASE II OF THISPROPOSAL WILL EXTEND THESE NEW TECHNIQUES TO DEVELOP A RUGGED SPECTROMETER FOR USE ON COMMERCIAL REACTORS. PHASE II WILL INCLUDE A FIELD TEST OF THE FT-IR MONITOR (PREFEREBLY AT MMST).