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US3877122A Expired / Lapsed US ⏱️ 0.0 years remaining

Method of fabricating thin quartz crystal oscillator blanks

Assignee: Motorola Solutions Inc
•
Filing: 1973-09-26
•
Granted: 1975-04-15
•
Expires: 1993-09-26
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Abstract

Abstract A method is provided for forming thin quartz crystals usable as a source of piezoelectric oscillation. A method is provided for fabricating quartz crystals to a thickness of one-half mil. Using state-of-the-art techniques the quartz crystal blank is thinned to the range of 5 to 10 mils. The sides of these quartz plates are lapped plane and parallel to the correct crystallographic orientation by conventional and well-known technology. Upon one side of this quartz plate would be deposited a layer of material some 10 to 15 mils thick. This material would be preferably one that matches the linear coefficient of expansion of the quartz as close as possible. Suitable materials include molybdenum, tungsten, Kovar, Therlo, Allegheny number 42, or polycrystalline silicon. The method of deposition of this backing material is important. The temperature of the quartz plate must be kept significantly below the curie point and preferably no higher than 250*C.

Inventors

  • 👤 Richard W Wilson

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-03 15:12
CPC Classifications
H; H03; H03H; H03H3/00; H03H3/007; H03H3/02; C; C30; C30B; C30B29/00; C30B29/10; C30B29/16; C30B29/18; C30B33/00; Y; Y10; Y10T; Y10T29/00; Y10T29/42

Claims Analysis

Total Claims: 10
Claim 1
Independent Claim 66 words
A METHOD OF MAKING A PIEZOELECTRIC CRYSTAL UNIT FORM A PLATE OF CRYSTALLINE MATERIAL HAVING A PAIR OF OPPOSING FACES OF WHICH BOTH ARE SNOOTH AHD FLAT, COMPRISING THE STEPS OF: DEPOSITING THE BACKING MATERIAL ON THE CRYSTALLINE PLATE AT A TERMPERATURE BELOW THE CURIE POINT OF THE CRYSTALLINE PLATE; THINNING THE CRYSTALLINE PLATE TO A DESIRED THICNKESS; AND REMOVING THE BACKING MATERIAL THROUGH CHEMICAL ETCHING.
Claim 2
Independent Claim 66 words
A METHOD OF MAKING A PIEZOELECTRIC CRYSTAL UNIT FORM A PLATE OF CRYSTALLINE MATERIAL HAVING A PAIR OF OPPOSING FACES OF WHICH BOTH ARE SNOOTH AHD FLAT, COMPRISING THE STEPS OF: DEPOSITING THE BACKING MATERIAL ON THE CRYSTALLINE PLATE AT A TERMPERATURE BELOW THE CURIE POINT OF THE CRYSTALLINE PLATE; THINNING THE CRYSTALLINE PLATE TO A DESIRED THICNKESS; AND REMOVING THE BACKING MATERIAL THROUGH CHEMICAL ETCHING.
Claim 3
Dependent Claim 25 words
The method of claim 1 wherein the backing material is selected from the group comprising molybdenum, tungsten, Kovar, Therlo, Allegheny No. 42 or polycrystalline silicon.
Claim 4
Dependent Claim 14 words
The method of claim 1 wherein said step of depositing is by ion plating.
Claim 5
Dependent Claim 15 words
The method of claim 1 wherein said step of depositing is by plasma arc spraying.
Claim 6
Dependent Claim 12 words
The method of claim 1 in which the crystalline material is quartz.
Claim 7
Dependent Claim 19 words
The method of claim 1 in which the backing material is deposited at a temperature no higher than 250*C.
Claim 8
Independent Claim 87 words
A method of making a piezoelectric crystal unit from a plate of crystalline material having a pair of opposing faces both of which are smooth and flat, comprising the steps of: forming an adherent molybdenum layer atop one surface of the crystalline plate at a temperature no higher than 250*C, and with its outward facing surface precisely parallel and uniform to the initial crystalline surface; thinning the crystalline plate to a desired thickness; and removing by chemical etching the layer of molybdenum material from the crystalline plate.
Claim 9
Independent Claim 87 words
A method of making a piezoelectric crystal unit from a plate of crystalline material having a pair of opposing faces both of which are smooth and flat, comprising the steps of: forming an adherent molybdenum layer atop one surface of the crystalline plate at a temperature no higher than 250*C, and with its outward facing surface precisely parallel and uniform to the initial crystalline surface; thinning the crystalline plate to a desired thickness; and removing by chemical etching the layer of molybdenum material from the crystalline plate.
Claim 10
Dependent Claim 12 words
The method of claim 7 in which the crystalline material is quartz.

References Cited (Backward Citations)

US3123953A Cited
US3325319A Cited
US3803774A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1978-04-14 1978-10-14 1979-04-15 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1982-04-14 1982-10-14 1983-04-15 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1986-04-14 1986-10-14 1987-04-15 $7700.00 Window Closed / Lapsed

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