A transducer comprising an acoustic energy generating means and a resonator. The acoustic energy generating means generates acoustic energy and is adapted for delivering an approximately uniform amount of acoustic energy to each unit of surface area on a substrate in a given time period when the substrate is rotating. The acoustic energy generating means has a surface area that is less than the surface area of the substrate, and may comprise a wedge shaped piezoelectric crystal. A resonator is attached to the acoustic energy generating means for transmitting the acoustic energy to the substrate.
This is a division of application Ser. No. 10/286,578, filed Nov. 1, 2002, now U.S. Pat. No. 6,791,242, which claims the benefit of provisional application 60/350,206, filed Nov. 2, 2001. Application Ser. No. 10/286,578 is incorporated herein by reference.
A megasonic cleaning apparatus configured to provide effective cleaning of a substrate without causing damage to the substrate is provided. The apparatus includes a megasonic probe, a transducer configured to energize the probe, and a heat transfer element disposed between the transducer and the probe. The heat transfer element may be configured to direct the sonic energy from the transducer toward specific areas of the probe so as to reduce the effect of normal-incident waves relative to shallow-angle waves. Alternatively, a rear end face of the probe may be configured for this purpose. Another embodiment provides a coupler disposed between the heat transfer element and the rear end face of the probe for directing the sonic energy from the transducer toward specific areas of the probe.
