IMPROVED MEGASONIC CLEANING EFFICIENCY USING AUTO-TUNING OF AN RF GENERATOR AT CONSTANT MAXIMUM EFFICIENCY

摘要

System and method of cleaning a substrate (202) includes a megasonic chamber (206) that includes a transducer (210) and a substrate (202). The transducer (210) is being oriented toward the substrate (202). A variable distance d separates the transducer (210) and the substrate (202). The system (200) also includes a dynamically adjustable RF generator (212) that has an output coupled to the transducer. The dynamically adjustable RF generator (212) can be controlled by a phase comparison of an oscillator output (306) voltage and a phase of an RF generator output voltage. The dynamically adjustable RF generator (212) can also be controlled by monitoring a peak voltage of an output signal and controlling the RF generator to maintain the peak voltage within a predetermined voltage range. The dynamically adjustable RF generator (212) can also be controlled by dynamically controlling a variable DC power supply voltage.