A megasonic immersion lithography exposure apparatus and method for substantially eliminating microbubbles from an exposure liquid in immersion lithography is disclosed. The apparatus includes an optical system for projecting light through a mask and onto a wafer.An optical transfer chamber is provided adjacent to the optical system for containing an exposure liquid. At least one megasonic plate operably engages the optical transfer chamber for inducing sonic waves in and eliminating microbubbles from the exposure liquid.