Abstract: An apparatus to produce acoustic cavitation by controlling cavitation events in a liquid insonification medium utilizing a waveform to excite a transducer with a series of bipolar inharmonic tone bursts having medium recovery intervals between respective bursts so that the medium repeatedly recovers from cavitation events between bursts. The apparatus may be used to clean a semiconductor wafer, to de-coat a painted surface having, to induce a chemical reaction, and/or to provide recycled paper made from inked paper de-inked by cavitation. Cavitation events are generated using a transducer and a waveform generator, e.g., square wave tone bursts, to excite the transducer with a signal controlled in frequency, burst repetition rate, duty-cycle and/or amplitude, e.g., utilizing bursts having a frequency between 500 KHz and 10 MHz, and a duty cycle between 0.1% and 70%.

Abstract: An apparatus to produce acoustic cavitation by controlling cavitation events in a liquid insonification medium utilizing a waveform to excite a transducer with a series of bipolar inharmonic tone bursts having medium recovery intervals between respective bursts so that the medium repeatedly recovers from cavitation events between bursts. The apparatus may be used to clean a semiconductor wafer, to de-coat a painted surface having, to induce a chemical reaction, and/or to provide recycled paper made from inked paper de-inked by cavitation. Cavitation events are generated using a transducer and a waveform generator, e.g., square wave tone bursts, to excite the transducer with a signal controlled in frequency, burst repetition rate, duty-cycle and/or amplitude, e.g., utilizing bursts having a frequency between 500 KHz and 10 MHz, and a duty cycle between 0.1% and 70%.

Abstract: An apparatus to produce acoustic cavitation by controlling cavitation events in a liquid insonification medium utilizing a waveform to excite a transducer with a series of bipolar inharmonic tone bursts having medium recovery intervals between respective bursts so that the medium repeatedly recovers from cavitation events between bursts. The apparatus may be used to clean a semiconductor wafer, to de-coat a painted surface having, to induce a chemical reaction, and/or to provide recycled paper made from inked paper de-inked by cavitation. Cavitation events are generated using a transducer and a waveform generator, e.g., square wave tone bursts, to excite the transducer with a signal controlled in frequency, burst repetition rate, duty-cycle and/or amplitude, e.g., utilizing bursts having a frequency between 500 KHz and 10 MHz, and a duty cycle between 0.1% and 70%.

Abstract: An apparatus to produce acoustic cavitation by controlling cavitation events in a liquid insonification medium utilizing a waveform to excite a transducer with a series of bipolar inharmonic tone bursts having medium recovery intervals between respective bursts so that the medium repeatedly recovers from cavitation events between bursts. The apparatus may be used to clean a semiconductor wafer, to de-coat a painted surface having, to induce a chemical reaction, and/or to provide recycled paper made from inked paper de-inked by cavitation. Cavitation events are generated using a transducer and a waveform generator, e.g., square wave tone bursts, to excite the transducer with a signal controlled in frequency, burst repetition rate, duty-cycle and/or amplitude, e.g., utilizing bursts having a frequency between 500 KHz and 10 MHz, and a duty cycle between 0.1% and 70%.

Abstract: A method and apparatus of in situ monitoring and dispersing unwanted particles in slurry used during CMP polishing. The method includes providing a slurry path, applying to the slurry path a microcavitation field of a first level to detect particles of a predetermined size, applying to the slurry path a microcavitation field of a second level that is capable of dispersing said particles, and after the second applying step, feeding the slurry to a CMP polishing unit. Particle size may be detected and/or the microcavitation field strength may be set according to particle size. In addition, field strength may be calibrated according to levels determined by polystyrene control particles of a known size and/or concentration. A single or dual transducer may apply the microcavitation.

Abstract: A method of testing thin film adhesion includes placing the film at the focus of a cavitation-producing sound beam. Time required to achieve spot erosion provide a measure of adhesion strength. No erosion occurs when insonification pressure amplitude remains below a threshold value. At pressures above a threshold value, cavitation intensity increases with pressure and erosion time decreases. A plot of erosion time versus pressure amplitude reveals a decreasing time versus insonification pressure. The intercept of the plot with the pressure axis corresponds to the instantaneous erosion of the thin film, and thus the adhesion strength. Further, the threshold value of the pressure at which no erosion occurs indicates infinite life of the thin film under cyclic loading and thus corresponds to the endurance limit, i.e., the fatigue strength, of the thin film. A corresponding apparatus is also disclosed.

Abstract: The invention provides a method and apparatus for suppressing hydrodynamic cavitation through the use of high frequency (>500 kHz) and high amplitude (>1 atmospheres) acoustic energy. The method includes biasing a transducer driving signal to generate an acoustic field having a positive pressure halves. The resulting acoustic field is imposed on a region where cavitation is to be preempted. A cavitation preempting acoustic field in the liquid is similar in effect as using a hyperbaric confinement for imposing hydrostatic pressure, a known method for suppressing cavitation. In this regime, suppression of cavitation will be due to imposing a dominant high amplitude, high-frequency pressure field to ensure that the gaps between the compressive pulses are shorter than 10?7 to 10?6 seconds, which is less than that typically necessary to cause cavitation.

Abstract: A method for removing paint from a substrate includes the steps of providing a sponge having a first surface for contact with the substrate, providing ultrasonic transducers in contact with a second surface of the sponge opposite from the first surface, saturating the sponge with water to provide a path of water extending from the transducers to the substrate, and activating the transducers to generate (i) a low frequency acoustic field; and (ii) a high frequency acoustic field; and thereby (iii) micron-sized vapor or cavitation bubbles which impinge upon the paint on the substrate to remove the paint from the substrate.

Abstract: The apparatus includes a sponge capable of having a fluid therein. The sponge has a first surface that can be placed in contact with the coating. High and low frequency transducers are positioned in contact with the second surface of the sponge. A method performing the invention includes the steps of providing a sponge having a first surface for contact with the substrate, providing ultrasonic transducers in contact with a second surface of the sponge opposite from the first surface, saturating the sponge with water to provide a path of water extending from the transducers to the substrate, and activating the transducers to generate (i) a low frequency acoustic field; and (ii) a high frequency acoustic field; and thereby (iii) micron-sized vapor or cavitation bubbles which impinge upon the paint on the substrate to remove the paint from the substrate.

Abstract: The invention provides a method and apparatus for suppressing hydrodynamic cavitation through the use of high frequency (>500 kHz) and high amplitude (>1 atmospheres) acoustic energy. The method includes biasing a transducer driving signal to generate an acoustic field having a positive pressure halves. The resulting acoustic field is imposed on a region where cavitation is to be preempted. A cavitation preempting acoustic field in the liquid is similar in effect as using a hyperbaric confinement for imposing hydrostatic pressure, a known method for suppressing cavitation. In this regime, suppression of cavitation will be due to imposing a dominant high amplitude, high-frequency pressure field to ensure that the gaps between the compressive pulses are shorter than 10−7 to 10−6 seconds, which is less than that typically necessary to cause cavitation.

Abstract: An article produced by acoustic cavitation by controlling cavitation events in a liquid insonification medium utilizing a waveform to excite a transducer with a series of tone bursts having medium recovery intervals between respective bursts so that the medium repeatedly recovers from cavitation events between bursts. Articles include a device made from a semiconductor wafer that is cleaned or otherwise processed by acoustic cavitation, a surface having been de-coated by acoustic cavitation, a chemical compound made from a chemical substance reacted by acoustic cavitation, and recycled paper made from inked paper de-inked by cavitation. Cavitation events are generated using a transducer and a waveform generator, e.g., square wave tone bursts, to excite the transducer with a signal controlled in frequency, burst repetition rate, duty-cycle and/or amplitude, e.g., utilizing bursts having a frequency between 500 KHz and 10 MHz, and a duty cycle between 0.1% and 70%.

Abstract: An apparatus that induces cavitation by controlling the onset, evolution, and/or intensity of cavitation events in a liquid medium to detect suspended particles, remove sub-micron particles from semiconductor wafers, de-ink paper or pulp, remove or test thin films, depaint substrates or panels, sculpt or erode surfaces, or control or accelerate liquid-based chemical reactions. Cavitation events are generated using at least one single-transducer module and a waveform generator, e.g., square wave tone bursts, to excite the transducer with pulse trains controlled in frequency, burst repetition rate, duty-cycle and/or amplitude. The waveform generator produces Fourier components which, when applied to the single transducer, achieve the same or similar acoustic field effect at a coaxing site as multiple focused coaxing high and low frequency transducers. Multiple single-transducer modules may also be deployed in a common environment for a desired application.

Abstract: Acoustic coaxing induced microcavitation (ACIM) for controlling the onset, evolution, and/or intensity of microcavitation events in a liquid or fluid medium to perform nanometer or micrometer particle detection in ultrapure liquids, sub-micron particle removal for precision cleaning of semiconductor wafers, deinking of paper or pulp, thin film removal from substrates, depainting substrates or panels, destructive and nondestructive measuring and testing of thin films, sculpting or erosion of surfaces, or control or acceleration of liquid-based chemical reactions. Instead of using a pair of sinusoidally excited, acoustically focused transducers operating at different fundamental resonance frequencies, ACIM events are instead generated using a single transducer and a waveform generator, e.g.

Abstract: The invention relates to the surgical cleaning of a semiconductor wafer through the inducement of cavitation on the surface of the wafer at the location of an adherent particle. Cavitation is induced by focusing two acoustic fields on the surface of the wafer. The two acoustic fields include a cavitation field having relatively low frequency focused on the wafer surface from a direction perpendicular to the wafer and a coaxing field of relatively high frequency focused on the wafer surface form a direction between 0 and 25 degrees from the wafer surface.

Abstract: A method of detecting particles in ultra-clean liquids using acoustic scattering and cavitation comprises inducing gas caps to form on the particles. The gas caps are then separated from the particles to form bubbles in the liquid. An acoustic signature received as an echo from the bubbles is detected. The detection of the acoustic signature indicates the presence of particles in the liquid.