Apparatus and methods for cleaning and/or processing delicate parts
First Claim
1. Ultrasonic transducer apparatus for producing ultrasonic energy within an ultrasound processing tank, comprising:
- a front drive plate for mounting the apparatus to the tank;
a cone-shaped steel backplate means for effecting a relatively flat impedance over a bandwidth of each of the plurality of harmonic frequencies, said backplate means having a threaded aperture; and
one or more elements compressed between the front plate and the backplate by a threaded bolt mechanically coupling the front plate and backplate, the bolt threading into the threaded aperture of the steel backplate so as to provide and maintain compressive force on the elements, whereby the elements are responsive to applied electrical energy to produce the ultrasound energy at a plurality of harmonic frequencies.
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Accused Products
Abstract
The invention utilizes harmonics of certain clamped ultrasound transducers to generate ultrasound within the liquid of an ultrasonic tank and in a frequency range of between about 100 khz to 350 khz (i.e., "microsonic" frequencies). The application of microsonic frequencies to liquid preferably occurs simultaneously with a sweeping of the microsonic frequency within the transducer'"'"'s harmonic bandwidth to reduce or eliminate (a) standing waves within the liquid, (b) other resonances, (c) high energy cavitation implosion, and (d) non-uniform sound fields, each of which is undesirable for cleaning and/or processing of semiconductor wafers and other delicate parts. The invention can also drive ultrasonic transducers such that the frequency of applied energy has a sweep rate within the ultrasonic bandwidth of the transducers; and that sweep rate is also varied so that the sweep rate is substantially non-constant during operation. Two or more transducer are sometimes used by the invention, in combination, to broaden the overall bandwidth of acoustical energy applied to the liquid around the primary frequency or one of the harmonics. The bandwidths of the transducer are made to overlap such that an attached generator can drive the transducers, in combination, to deliver ultrasound to the liquid in a broader bandwidth.
96 Citations
12 Claims
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1. Ultrasonic transducer apparatus for producing ultrasonic energy within an ultrasound processing tank, comprising:
- a front drive plate for mounting the apparatus to the tank;
a cone-shaped steel backplate means for effecting a relatively flat impedance over a bandwidth of each of the plurality of harmonic frequencies, said backplate means having a threaded aperture; and
one or more elements compressed between the front plate and the backplate by a threaded bolt mechanically coupling the front plate and backplate, the bolt threading into the threaded aperture of the steel backplate so as to provide and maintain compressive force on the elements, whereby the elements are responsive to applied electrical energy to produce the ultrasound energy at a plurality of harmonic frequencies. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
- a front drive plate for mounting the apparatus to the tank;
Specification