Megasonic processing apparatus with frequency sweeping of thickness mode transducers

A megasonic processing system comprising:

• two or more tanks, each tank adapted to contain fluid and one or more parts to be processed;
• one or more piezoelectric transducers coupled to each tank, each transducer having a fundamental resonant frequency of at least 300 KHz;, wherein the transducers are capable of providing vibrations to the tanks and their contents;
• two or more generators coupled to the transducers for supplying driving signals to the transducers, wherein the transducers are grouped by similar resonant frequencies, and wherein each group of transducers is powered by a separate generator that generates a driving signal having a variable frequency that varies within a frequency range that includes the resonant frequencies of all the transducers of its associated group.

A megasonic cleaning apparatus comprising:

• one or more piezoelectric transducers, each having a fundamental resonant frequency in thickness mode vibration at a frequency of at least 300 KHz;
• a tank adapted to contain cleaning fluid and one or more parts to be cleaned, said one or more transducers adapted for providing vibrations to cleaning fluid and parts in the tank;
• a generator coupled to said one or more transducers for supplying a driving signal at a predetermined frequency range and sweep rate, wherein the frequency range includes the resonant frequency of all said one or more transducers, and wherein the generator includes programmable means for defining a sweep frequency range and a sweep rate for the driving signal.

A megasonic processing method comprising:

• providing one or more piezoelectric transducers, each having a fundamental resonant frequency of at least 300 KHz;
• providing a tank adapted to contain fluid and one or more parts to be processed, wherein said one or more transducers are coupled to the tank and adapted for providing vibrations to the tank and its contents;
• generating and supplying a driving signal to the transducers, wherein the driving signal has a variable frequency throughout a frequency range that includes the resonant frequencies of all the transducers.