Approaches to deep ultraviolet photolithography utilizing acid hardened resin photoresist systems
Abstract
This paper describes continuing efforts in the development of acid hardened resin (AHR) resist systems for use in deep UV photolithography. The paper is composed of two sections. The first section deals with further evaluation of a conventional negative-tone deep-UV resist, XP-8843. A study of delay time between exposure and postexposure bake was carried out over a 62 min period. In particular, the linewidth versus exposure curve was generated at 2, 32, and 62 min delay times. Representative SEM cross sections at each time interval were also compared. The authors conclude that no significant time effect is evident, indicative that acid diffusion does not play a role in the 62 min time frame. The effect of defocus on sidewall angle has been evaluated over a 1.8 μ focal range as well. The sidewall angle varied from 85° to 89° reentrant over the entire focal range. Finally, results for XP-8843 at 1.4 μ coating thickness are shown. The second section introduces the silylated AHR (SAHR) process, whereby a highly absorbing resist, such as SAL601-ER7, is treated with hexamethyldisilazane. The exposed, crosslinked areas show virtually no reactivity with HMDS, and the unexposed areas incorporate 8.0% silicon in the film. In this manner, subsequent dry etching leads to a positive tone image.
- Publication:
-
Journal of Vacuum Science Technology B: Microelectronics and Nanometer Structures
- Pub Date:
- November 1989
- DOI:
- 10.1116/1.584502
- Bibcode:
- 1989JVSTB...7.1620T