Patent ID: 6890390

Claim:
A method for cleaning the surface of a substrate, said method comprising the steps of: arranging a plurality of ‘N’ transducer elements into an array, each transducer element for propagating a respective ultrasonic wave; providing a respective electrical signal S N to each respective transducer element to vibrate each said element, with each said electrical signal S N having signal parameters including a voltage V N and phase θ N ; interposing a fluid medium between said array and the substrate to transmit said ultrasound waves from said array to the substrate; and controlling said signal parameters provided to each said element to direct ultrasonic energy to a first location on the substrate surface and establish a pressure peak at said first location; and altering said signal parameters provided to each said element to direct ultrasonic energy to a second location on the substrate surface and establish a pressure peak at said second location with said pressure peak at said first location being substantially equal to said pressure peak at said second location.