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Today's liquid photoresist market has a volume of 2300 tons/year, or about $220 million. The bulk of this market consists of the positive-tone diazonaphthoquinone/novolak (DNQ/N) resist materials. While the relative importance for the different market segments is generally accepted, the estimated values for their size can vary greatly from source to source, in part as a result of differences in definitions. The largest market segment is still broadband exposure, followed by submicron g-line applications and TFT-TN or thick film uses, and a small but quickly growing i-line business. The dominance of DNQ/novolak resists in optical lithography is (still) almost absolute, their performance characteristics have defined the parameters for nearly all of today's industrial semiconductor patterning processes, and they have set the standard against which all new resist chemistry will be measured. This situation has obtained since about 1972, when DNQ/novolak resists were first introduced for 16 Kbit DRAM production, and little change is expected in the near future. Even for the 64 Mbit DRAM expected to go into large-scale production in 1994 or 1995, it is not clear at present whether other patterning methods will be required, and whether a new resist technology specially adapted to e.g. DUV lithography will emerge.
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