ABSTRACT
I. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285
II. Wet Vapor Resist Stripping Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285
III. Resist Removal Mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 287
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 291
At present, wet-cleaning using ultrapure water (UPW) and chemicals is a mainstream technology to
clean substrate surfaces of ultra large-scale integration (ULSI) devices. RCA cleaning developed by
Kern and Puotinen of Radio Corporation of America in 1970 is the most widely used wet-cleaning
technique [1,2]. The RCA cleaning is composed of NH4OH/H2O2 cleaning andHCl/H2O2 cleaning. Organic films, such as photoresist films, are hard to remove by the RCA cleaning method. O2
plasma ashing is commonly used to remove them. The resist is burnt and ashed by oxygen radical in
O2 plasma. After such steps like photoresist coating, exposure, development, etching, and ion
implantation, the residual resist waste needs to be removed.
