Method and apparatus for fabricating a piezoelectric resonator to a resonant frequency
AssigneeTFR Technologies, Inc.
InventorKenneth M. Lakin
Life of this patent
Estimating the term…
Abstract
Resonator fabricating method and apparatus employ the resonance conditions of the piezoelectric resonator itself to control an RF-powered plasma etching or deposition process. In its basic implementation, the apparatus does not require monitoring of the resonant frequency of the resonator as it is being trimmed. Rather, the resonator provides an impedance which changes as the plasma action changes the thickness of the resonator and thereby changes the resonant frequency of the piezoelectric resonator. The changing impedance in turn changes the rate of plasma action until the action substantially stops with the resonant frequency of the resonator substantially equal to the frequency of the RF source.
Claims22
An apparatus for adjusting the resonant frequency of a piezoelectric resonator by changing the thickness of the resonator, comprising:
- a pair of electrodes between which a piezoelectric resonator is placed;
- an RF source operable at a desired resonant frequency for the piezoelectric resonator and at a desired power level, the RF source operatively connected to the electrodes to form a circuit therewith;
- and
- a gas source for injecting gas between the electrodes, the RF source energizing the gas to form a plasma that acts to change the thickness of the piezoelectric resonator;
- the resonator providing an impedance in the circuit which changes as the plasma action changes the thickness of the resonator and thereby changes the resonant frequency of the piezoelectric resonator, the changing impedance changing the rate of plasma action until, with the RF source set at the desired power level, the action substantially stops with the resonant frequency of the piezoelectric resonator substantially equal to the frequency of the RF source.
A method for adjusting the resonant frequency of a piezoelectric resonator by changing the thickness of the resonator, comprising:
- placing a piezoelectric resonator between a pair of electrodes;
- injecting a gas between the electrodes;
- and
- applying power from an RF source operating at a desired resonant frequency for the piezoelectric resonator and at a desired power level to the electrodes to energize the gas to form a plasma that acts to change the thickness of the piezoelectric resonator,
- the resonator providing an impedance which changes as the plasma action changes the thickness of the resonator and thereby changes the resonant frequency of the piezoelectric resonator, the changing impedance changing the rate of plasma action until, with the RF source set at the desired power level, the action substantially stops with the resonant frequency of the piezoelectric resonator substantially equal to the frequency of the RF source.
A method for adjusting the resonant frequency of a piezoelectric resonator by changing the thickness of the resonator, comprising:
- placing a piezoelectric resonator between a pair of electrodes;
- operatively connecting an RF source to the electrodes;
- injecting a gas between the electrodes to form a plasma;
- setting the RF source to a desired resonant frequency for the piezoelectric resonator;
- setting power of the RF source to a level such that the plasma extinguishes when the piezoelectric resonator's resonant frequency substantially equals the RF source frequency;
- and
- applying the power of the RF source at the desired resonant frequency to the electrodes to energize the gas to form the plasma, the plasma acting to change the thickness of the piezoelectric resonator until the resonator reaches the desired resonant frequency provided by the RF source.
Dependencies are inferred from the claim text.