Practical Photoresist Processing

Level: Introductory Length: 4 hours Format: In-Person Lecture Intended Audience: This material is directed to engineers, scientists and managers who work with photoresist materials. Some chemical background is helpful but not required. Description: Photolithography is the technique underlying all integrated circuit manufacture. To a large extent, the minimum feature size and the performance of ICs is determined by the resolution achievable in this step. Also, the process yield has a strong impact on a Fab's economy. The troubleshooting of photoresist performance is therefore a key concern to every microlithography engineer. However, this requires a highly interdisciplinary understanding of many areas, from photochemistry to polymer science to optics, that are usually not taught in a unified way in most educational curricula. In this course, photoresist processing is examined by walking a wafer through the lithographic sequence, beginning with the wafer preparation and ending when the resist feature has been prepared for dry etching. Both classic near-UV DNQ/novolak resists as well as chemically amplified systems (248 and 193 nm as well as EUV) will be covered. The chemical changes occurring in photoresists during the different process steps will be discussed. Pitfalls and failure modes will be pointed out at every step and correlated to the underlying properties of the photoresist materials. The aim of the course is to give microlithography engineers a practical basis from which to begin the detective work involved in identifying the root cause of a processing problem. Learning Outcomes: This course will enable you to: - evaluate and compare different lithographic materials for their suitability-to-task - explain the role of the individual components in achieving overall resist performance - weigh the performance increase of advanced processing schemes against added process complexity - identify the basic chemical makeup of photoresist materials - solve problems in resist processing by reducing them to their chemical root cause Instructor(s): Ralph R. Dammel has been actively involved in x-ray, e-beam, 157 nm, 193 nm, DUV, i- and g-line resist research since 1986. Beyond photoresists, his research interests include anti-reflective coatings and other performance enhancing materials, Directed Self Assembly, novel carbon materials, and other performance materials. He is currently employed as Research Fellow for EMD Electronics and is based in Philadelphia, PA. Event: SPIE Advanced Lithography + Patterning 2025 Course Held: 27 February 2025