High-performance profiles and characteristics of chemically amplified resist

Abstract

We investigated means of the linewidth control of the 0.20 micrometers isolated line of the chemically amplified resist with a conventional exposure method (without specific illumination optics or mask). In order to clarify the influence of the light intensity of the optical image on a wafer, we calculated the optical image by photolithography simulator `Prolith/2'. This result suggests that the CD deviation between isolated lines and dense lines depends on the optical parameters. For the purpose of controlling the CD deviation between isolated and dense lines, we tried to control the acid diffusion length and the dissolution characteristic. In order to control the acid diffusion length, post-exposure baking temperature and an acid diffusion inhibitor worked effectively. On the other hand, an dissolution inhibitor having several functional groups which was able to form hydrogen-bonds with hydroxyl groups of the base polymer contributed to adjustment of dissolution characteristics. Using these results, we developed a resist of which the isolated and dense line were quite well controlled. Further, this resist had a good resolution and a good pattern profile and resolved 0.18 micrometers lines and spaces pattern using KrF excimer laser stepper (Nikon NSR, NA equals 0.55).