Improved underlayers for acid amplified resists

Acid amplified resists represent a major development in lithography in the last few years. It is recognized that for precise CD control with these resists in device manufacturing, it is required that the processing environment be free of any basic contaminants. Top coat protection of the resist films in conjunction with rigorous exclusion of basic chemical vapors in the work area has been recommended to minimize the effects of environmental contaminants. Another important variable in determining the resist performance is the effect of substrate chemistry which has received little attention in the literature. This paper provides an understanding of these effects and gives a general method to circunmvent the problem. © 1994.