A NON-INVASIVE SENSOR TECHNIQUE FOR PROCESS CONTROL IN PLASMA PROCESSING REACTORS

THIS PROPOSAL ADDRESSES A PROGRAM TO DEVELOP A NONINVASIVE, IN-SITU SENSOR TECHNIQUE FOR APPLICATION IN SEMICONDUCTOR MANUFACTURING. THE PROPOSED SENSOR IS APPROPRIATE FOR DRY PLASMA PROCESSES SUCH AS DEPOSITION AND ETCHING WHICH ARE KEY STEPS IN SEMICONDUCTOR FABRICATION LINE. THE PROPOSED TECHNIQUE CAN PERFORM QUANTITATIVE MEASUREMENT OF CONSTITUENT SPECIES, DETECTION OF APPEARANCE/DISAPPEARANCE OF SPECIES AND CONTAMINANTS, AND END POINT DETECTION. THE ULTIMATE OBJECTIVE OF THIS MULTI-PHASE EFFORT IS TO PROVIDE A RELIABLE PROCESS CONTROL METHOD WITH THE PROPOSED SENSOR AS THE NUCLEUS OF THE PROCESS CONTROL LOOP. THE PROPOSED TECHNIQUE USES LASER INDUCED FLUORESCENCE (LIF)WITH AN INNOVATION TO PERFORM RAPID TEMPORAL AND SPATIAL SCANNING AND HIGH DEGREE OF ACCURACY AND SENSITIVITY. THE INNOVATION INVOLVES USE OF AN ACOUSTO-OPTICAL TUNABLE FILTER DEVELOPED AT SCIENTIFIC RESEARCH ASSOCIATES TO OBTAINHIGH SPECTRAL RESOLUTION WHILE MAINTAINING GOOD SPATIAL RESOLUTION, HIGH SENSITIVITY AND HIGH OPTICAL THROUGHPUT. IN PHASE I THE TECHNIQUE WILL BE DEMONSTRATED IN A CF4 PLASMA WHICH IS WIDELY USED IN SILICON ETCHING.