Process for mass producing high frequency crystal resonators
First Claim
1. In a process for producing a plurality of high frequency crystal resonators from a resonating material, the step of:
- etching the resonating material to form a cantilevered resonating membrane on a region of each resonator bordered by at least one thicker support structure.
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Abstract
A process for making a plurality of quartz thickness shear resonators with resonating means for use in high frequency oscillators with operating frequencies of 30 MHz or greater. The invention includes grinding a single crystal quartz wafer to achieve a highly uniform thickness, thus enhancing uniformity of the resonators produced. The invention also includes etching the quartz wafer to form a plurality of resonators, each having a support structure and a much thinner etched resonating membrane cantilevered at the support structure. In addition, the design of the support structure is such that a sloped edge occurs during membrane etching between the support structure and the membrane, thus facilitating the application of electrodes extending from the support structure to the membrane. Yet another aspect of the invention is to perform a fine-tune etching during the formation and tuning of the resonating membranes, thus further enhancing the uniformity of the resonator frequencies across the wafer.
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Citations
26 Claims
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1. In a process for producing a plurality of high frequency crystal resonators from a resonating material, the step of:
etching the resonating material to form a cantilevered resonating membrane on a region of each resonator bordered by at least one thicker support structure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. In a process for producing a plurality of high frequency crystal resonators, the steps of:
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defining a plurality of resonators having resonator membranes on a wafer of resonating material; probing each resonating membrane to measure its frequency; determining the deviation of the measured frequency from a desired frequency; calculating an etching time for each resonator from the measured deviation; and etching each membrane for the calculated etching time to fine-tune its frequency to the desired frequency, thereby increasing the uniformity of frequencies of resonators defined within the wafer. - View Dependent Claims (12, 13, 14, 15, 16, 17, 22)
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18. In a process for producing a plurality of high frequency crystal resonators, the steps of:
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grinding a wafer of resonating material to uniform thickness; measuring the wafer to detect nonuniformities in thickness, then fine-grinding the wafer to correct for detected nonuniformities; coating the wafer with conductive metal and etching the conductive metal to define a plurality of resonator patterns; etching the resonating material along the resonator patterns to define a plurality of resonators; etching the resonating material to carve on each resonator a resonating membrane cantilevered from a thicker support structure; probing each resonator membrane to measure its frequency and to determine the deviation of the measured frequency from a desired frequency; calculating an etching time for each resonator from the determined deviation; etching each membrane for the calculated etching time to fine-tune its frequency to the desired frequency, thereby increasing the uniformity of frequencies resonators defined within the wafer; applying resonating means to each resonator; measuring each resonator to determine its frequency; identifying resonators having frequencies falling within a predetermined acceptable frequency range; and breaking the resonators out of the wafer. - View Dependent Claims (19, 20, 21, 23, 24, 25, 26)
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Specification