Patent ID: 8409360

Claim:
A cleaning method in a process of liquid immersion lithography that comprises using a photoexposure device provided with at least an optical lens member, a wafer stage, a liquid-introducing flow line and a liquid-discharging flow line, introducing a medium for liquid immersion lithography into a space between the optical lens member and an object for photoexposure mounted on the wafer stage, through the liquid-introducing flow line, then thus filling the space with the medium for liquid immersion lithography and simultaneously discharging the medium for liquid immersion lithography through the liquid-discharging flow line to attain photoexposure; after photoexposure, introducing a cleaning liquid through the same introducing flow line as that used for the introduction of the medium for liquid immersion lithography and contacting the cleaning liquid with the optical lens member for a predetermined period of time so as to clean the optical lens member, and discharging the used cleaning liquid through the same discharging flow line as that used for the discharging of the medium for liquid immersion lithography, wherein the cleaning liquid comprises 7 to 25% by mass of polyoxyethylene lauryl ether, and a balance of water.