US5650075A
Expired / Lapsed
US
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Method for etching photolithographically produced quartz crystal blanks for singulation
Assignee: CTS Corp
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Filing: 1995-05-30
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Granted: 1997-07-22
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Expires: 2015-05-30
Abstract
Abstract A method for etching (200) photolithographically produced quartz crystal blanks for singulation. First, a quartz wafer is plated on both sides with metal and subsequently coated on both sides with photoresist (202). Second, the photoresist is patterned and developed and the metal layers etched to define the periphery of a quartz blank with a narrow quartz channel exposed between the blank to be singulated and the parent quartz wafer (204). Third, the quartz channel is preferentially etched partially into the wafer along parallel atomic planes to provide a mechanically weak junction between the quartz wafer and the blank to be singulated, while the periphery around the remainder of the quartz blank is etched completely through the parent quartz wafer (206). Fourth, the photoresist layers are stripped from the quartz wafer (208). Finally, the quartz blank is cleaved substantially along the bottom of the quartz channel to singulate the crystal blank from the wafer (210).
Inventors
- 👤 Kevin L. Haas
- 👤 Robert S. Witte
- 👤 Charles L. Zimnicki
- 👤 Iyad Alhayek
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 16:33
CPC Classifications
H; H03; H03H; H03H3/00; H03H3/007; H03H3/02; H10; H10N; H10N30/00; H10N30/01; H10N30/08; H10N30/082
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
118 words
A method of etching photolithographically produced quartz crystal blanks for singulation, comprising: providing a quartz wafer coated with at least one metal layer and a photoresist layer, respectively; removing a pattern from the photoresist and the metal layer to expose a quartz channel having a bottom and connecting to a remaining quartz periphery defining a quartz blank; etching the bottom of the channel along substantially parallel quartz atomic planes, whereby the bottom of the channel does not etch through the quartz wafer; stripping the remaining photoresist layer from the metal layer; and cleaving substantially along the bottom of the channel and substantially aligned with a quartz crystal atomic plane, to singulate the quartz blank from the quartz wafer.
Claim 2
Independent Claim
118 words
A method of etching photolithographically produced quartz crystal blanks for singulation, comprising: providing a quartz wafer coated with at least one metal layer and a photoresist layer, respectively; removing a pattern from the photoresist and the metal layer to expose a quartz channel having a bottom and connecting to a remaining quartz periphery defining a quartz blank; etching the bottom of the channel along substantially parallel quartz atomic planes, whereby the bottom of the channel does not etch through the quartz wafer; stripping the remaining photoresist layer from the metal layer; and cleaving substantially along the bottom of the channel and substantially aligned with a quartz crystal atomic plane, to singulate the quartz blank from the quartz wafer.
Claim 3
Dependent Claim
79 words
The method of claim 1, wherein the etching step includes: exposing the bottom of the channel to etchant for a sufficiently long time to at least partially mechanically weaken the quartz wafer in proximity to the channel and exposing the bottom of the channel to etchant for a sufficiently short time so as not to etch through the quartz wafer; and exposing the periphery defining the quartz blank for a sufficiently long time to etch through the quartz wafer.
Claim 4
Dependent Claim
37 words
The method of claim 1, wherein the cleaving step includes singulating the quartz blank from the quartz wafer by applying a tensile force to an interior portion of the channel, whereby fragmentation of the quartz is minimized.
Claim 5
Dependent Claim
17 words
The method of claim 1, wherein the cleaving step includes providing a plurality of individual quartz blanks.
Claim 6
Dependent Claim
25 words
The method of claim 1, wherein the removing and etching steps are provided on both sides of the quartz wafer to include substantially opposite channels.
Claim 7
Dependent Claim
26 words
The method of claim 5, wherein the removing step includes providing a pattern having the two substantially opposite channels in substantial alignment before the etching step.
Claim 8
Dependent Claim
21 words
The method of claim 6, wherein the removing step includes the two substantially opposite channels not sharing an intersecting atomic plane.
Claim 9
Dependent Claim
58 words
The method of claim 1, wherein the pattern is chosen to define a channel width substantially narrower than the width of the periphery defining the quartz blank, whereby the bottom of the narrower channel will etch slower than the wider periphery defining the quartz blank due to the increased depletion rate of active etchant in the narrower channel.
Claim 10
Dependent Claim
31 words
The method of claim 1, wherein the etching step includes the bottom of the channel having a channel depth of about 10 to about 40 percent of the quartz wafer thickness.
Claim 11
Dependent Claim
28 words
The method of claim 1, wherein the etching step includes the bottom of the channel having a channel depth of about 25 percent of the quartz wafer thickness.
Claim 12
Dependent Claim
25 words
The method of claim 1, wherein the etching step includes etchant from at least one of ammonium fluoride, ammonium bifluoride, hydrofluoric acid, and commercial etchants.
Claim 13
Dependent Claim
21 words
The method of claim 1, wherein the stripping step includes stripper from at least one of acetone, alcohol, and commercial stripper.
Claim 14
Dependent Claim
46 words
The method of claim 1, wherein the cleaving step includes rigidly clamping the quartz wafer and applying a bending force to the quartz blank to tensilely fracture the bottom of the channel substantially along an atomic plane to singulate the quartz blank from the quartz wafer.
Claim 15
Independent Claim
160 words
A method of etching photolithographically produced quartz crystal blanks for singulation, comprising: providing a quartz wafer coated with a metal layer and a photoresist layer, respectively, on both sides of the wafer; removing a pattern from the photoresist and the metal layers on both sides of the quartz wafer to expose two opposing quartz channels each having a bottom and connecting to a remaining quartz periphery defining a quartz blank; etching the peripheries defining the quartz blank and the bottoms of the two channels along substantially parallel quartz atomic planes, whereby etched walls of the channels are formed and defined by the substantially parallel atomic planes and the bottoms of the channels do not etch through the quartz wafer; stripping the photoresist from the metal layers; and cleaving substantially along the bottom of one channel and substantially aligning with a quartz crystal atomic plane to singulate the quartz blank from the quartz wafer, whereby fragmentation of the quartz is minimized.
Claim 16
Independent Claim
160 words
A method of etching photolithographically produced quartz crystal blanks for singulation, comprising: providing a quartz wafer coated with a metal layer and a photoresist layer, respectively, on both sides of the wafer; removing a pattern from the photoresist and the metal layers on both sides of the quartz wafer to expose two opposing quartz channels each having a bottom and connecting to a remaining quartz periphery defining a quartz blank; etching the peripheries defining the quartz blank and the bottoms of the two channels along substantially parallel quartz atomic planes, whereby etched walls of the channels are formed and defined by the substantially parallel atomic planes and the bottoms of the channels do not etch through the quartz wafer; stripping the photoresist from the metal layers; and cleaving substantially along the bottom of one channel and substantially aligning with a quartz crystal atomic plane to singulate the quartz blank from the quartz wafer, whereby fragmentation of the quartz is minimized.
Claim 17
Dependent Claim
86 words
The method of claim 14, wherein the etching step includes: exposing the bottom of the channels to etchant for a sufficiently long time to at least partially mechanically weaken the quartz wafer in proximity to the channels and exposing the bottom of the channels to etchant for a sufficiently short time so as not to etch through the quartz wafer; and exposing the peripheries on opposing sides of the quartz wafer and defining the quartz blank for a sufficiently long time to etch through the wafer.
Claim 18
Dependent Claim
37 words
The method of claim 14, wherein the cleaving step includes singulating the quartz blank from the quartz wafer by applying a tensile force to an interior portion of one channel, whereby fragmentation of the quartz is minimized.
Claim 19
Dependent Claim
13 words
The method of claim 14, wherein a plurality of quartz blanks are defined.
Claim 20
Dependent Claim
30 words
The method of claim 14, wherein the removing step includes the pattern on opposing sides of the quartz wafer having the two channels in substantial alignment before the etching step.
Claim 21
Dependent Claim
16 words
The method of claim 18, wherein the two channels do not share an intersecting atomic plane.
Claim 22
Dependent Claim
67 words
The method of claim 14, wherein the patterns on opposing sides of the quartz wafer are chosen to define at least one channel width substantially narrower than the width of the peripheries defining the quartz blank, whereby the bottom of the narrower channel will etch slower than the wider peripheries defining the quartz blank due to the increased depletion rate of active etchant in the narrower channel.
Claim 23
Dependent Claim
31 words
The method of claim 14, wherein the etching step includes the bottom of each channel having a channel depth of about 10 to about 40 percent of the quartz wafer thickness.
Claim 24
Dependent Claim
28 words
The method of claim 14, wherein the etching step includes the bottom of each channel having a channel depth of about 25 percent of the quartz wafer thickness.
Claim 25
Dependent Claim
46 words
The method of claim 14, wherein the cleaving step includes rigidly clamping the quartz wafer and applying a bending force to the quartz blank to tensilely fracture the bottom of one channel substantially along an atomic plane to singulate the quartz blank from the quartz wafer.
Claim 26
Independent Claim
254 words
A method of etching photolithographically produced quartz crystal blanks for singulation, comprising: providing a quartz wafer coated with a metal layer and a photoresist layer, respectively, on both sides of the wafer; removing a predetermined pattern from the photoresist and the metal layers on both sides of the quartz wafer to expose two substantially aligned opposing quartz channels each having a bottom and connecting to a remaining quartz periphery defining a quartz blank, whereby the channels are defined with a width substantially narrower than the width of the peripheries defining the quartz blank; etching the peripheries defining the quartz blank and the bottoms of the two channels along substantially parallel quartz atomic planes, whereby etched wails of the channels are formed and defined by the substantially parallel atomic planes, the bottom of each channel is etched about 25 percent the quartz wafer thickness, and the channels do not intersect each other, the quartz wafer being exposed to etchant for a sufficient time to etch through the peripheries defining the quartz blank but to only etch each channel about 25 percent of the wafer thickness due to the increased depletion rate of active etchant in the narrow channels; stripping the photoresist from the metal layers; and cleaving substantially along the bottom of one channel by rigidly fixing the quartz wafer and applying a bending force to the quartz blank to tensilely fracture substantially along a quartz crystal atomic plane to singulate the quartz blank from the quartz wafer, whereby fragmentation of the quartz is minimized.
Claim 27
Independent Claim
254 words
A method of etching photolithographically produced quartz crystal blanks for singulation, comprising: providing a quartz wafer coated with a metal layer and a photoresist layer, respectively, on both sides of the wafer; removing a predetermined pattern from the photoresist and the metal layers on both sides of the quartz wafer to expose two substantially aligned opposing quartz channels each having a bottom and connecting to a remaining quartz periphery defining a quartz blank, whereby the channels are defined with a width substantially narrower than the width of the peripheries defining the quartz blank; etching the peripheries defining the quartz blank and the bottoms of the two channels along substantially parallel quartz atomic planes, whereby etched wails of the channels are formed and defined by the substantially parallel atomic planes, the bottom of each channel is etched about 25 percent the quartz wafer thickness, and the channels do not intersect each other, the quartz wafer being exposed to etchant for a sufficient time to etch through the peripheries defining the quartz blank but to only etch each channel about 25 percent of the wafer thickness due to the increased depletion rate of active etchant in the narrow channels; stripping the photoresist from the metal layers; and cleaving substantially along the bottom of one channel by rigidly fixing the quartz wafer and applying a bending force to the quartz blank to tensilely fracture substantially along a quartz crystal atomic plane to singulate the quartz blank from the quartz wafer, whereby fragmentation of the quartz is minimized.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-07-21 | 2001-01-20 | 2001-07-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-07-21 | 2005-01-20 | 2005-07-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-07-21 | 2009-01-20 | 2009-07-22 | $7700.00 | Window Closed / Lapsed |