Apparatus for treating wafers utilizing megasonic energy

Claim 1

Apparatus for treating the surfaces of a plurality of wafers comprising a container means arranged to hold a body of treatment fluid, said container means having an open upper side for accepting a cassette containing a plurality of vertically disposed wafers, means for supporting said cassette from the open upper side of said container with the wafers carried thereby beneath the surface of the treatment fluid in said container, a transducer carrier suspended from the open upper side of said container in said container, said carrier being suspended above the bottom of said container beneath the wafers and having a megasonic transducer arranged to project a beam of ultrasonic energy upwardly over the vertical surfaces of said wafers, said transducer carrier having a width substantially less than the width of said cassette, means for energizing said megasonic transducer to oscillate at a frequency of between about 0.2 and 5 Mhz, and means for moving said transducer carrier transversely of its width parallel with the wafer surfaces and transversely of the container whereby said ultrasonic energy beam contacts and treats the entire surface of the wafers therein.