DEVELOPMENT OF ON-MACHINE PRINTING SYSTEM FOR SPATIAL FILTER

An on-machine printing system for a spatial filter has been developed to detect small particles on the memory-mat of a 0.3mum LSI. A minicop y film is used for the base of spatial filters. A pattern on the filte r is printed by a thermal bead using a ribbon painted with ink of synt hetic resin. The maximum size of the printed spatial filter is 16X16 m m. The transmission factors of printed and transparent parts are 0.92% and 92% respectively. The printing time is 5 seconds. The signal obta ined at memory-mat decreases to 4% using this spatial filter and 0.6mu m standard particles are detected at an SN ratio of 3.