Papers by Author: Yoichi Isago

Abstract: It is well-known that ion-implant doses greater than 5E14 atoms/cm2 can create an amorphous carbon-like layer “crust”, and also that this crust is extremely difficult to dissolve with wet chemicals. In practice, a combination of dry plasma ashing and wet chemical removal is used to eliminate the photoresist. In this study, a novel photoresist stripping technique is proposed. We have improved wet vapor photoresist stripping technique [1] using the mixture of high-speed steam flow and purified water droplets. Relatively low pressure clean steam is mixed with purified water in the nozzle, and sprayed on a photoresist coated Si wafer. We have also developed a pre-treatment method in a chamber with keeping both temperature and humidity constant, in order to strip post ion-implanted photoresit. The most significant feature of this proposed technique is that we use water only; hence we are able to strip photoresist without chemicals.

Abstract: A novel cleaning technique using steam-water mixed spray is proposed. Relatively low-pressure super-purified steam (0.1 MPa - 0.2 MPa) is mixed with super-purified water in a nozzle, and then sprayed on a silicon wafer surface, which is located at approximately 10 mm from the nozzle. The most striking result of this proposed technique is that we are able to clean a wafer surface, i.e., to eliminate fine particles, without using any chemicals.