NEGATIVE PHOTORESISTS FOR OPTICAL LITHOGRAPHY

Negative photoresists are materials that become insoluble in developin g solutions when exposed to optical radiation, They were the first sys tems used to pattern semiconductor devices, and still comprise the lar gest segment of the photoresist industry because they are widely used to define the circuitry in printed wiring boards, However, the current use of negative resists in the semiconductor industry has been limite d by past difficulties in achieving high-resolution patterns, Recent a dvances in the chemistry of negative-resist systems, however, have pro vided materials with wide processing latitude and high resolution that are used to manufacture IBM's advanced CMOS devices and to achieve hi gh-aspect-ratio patterns for micromachining applications, This paper p rovides an overview of the history and chemistry of negative-resist sy stems and their development in IBM.