Patent US3930914A successfully refreshed from Google Patents.
US3930914A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Thinning semiconductive substrates
Assignee: AT&T Inc
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Filing: 1974-08-01
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Granted: 1976-01-06
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Expires: 1994-08-01
Abstract
Abstract In making a target for a television camera tube, it is necessary to thin the backside of a semiconductive substrate, which is opposite a face having a diode array thereon. To thin the substrate, it is positioned face down on a fluid nondeleterious to the substrate and diode array. The fluid is contained in a cavity of a holding device. The positioning is such that there is no space between the fluid and the substrate. An apertured top member is then mounted on the substrate and the holding device to retain the substrate on the fluid. The assembly of the holding device and top member with the substrate therebetween is immersed and rotated in an etchant to thin the backside of the substrate through the aperture of the top member. The fluid provides a tight seal on the face of the substrate to prevent the etchant from damaging such face and the diode array thereon. A vent extending from the cavity of the holding device to its outer edge assists in the subsequent removal of the substrate from the cavity.
Inventors
- 👤 Harold Arthur Hetrich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 01:43
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/69; H10P50/691; H10P50/692; H01; H01J; H01J29/00; H01J29/02; H01J29/10; H01J29/36; H01J29/39; H01J29/45; H01J29/451; H01J29/453; H01J29/455; H01J9/00; H01J9/20; H01J9/233; H10D; H10D99/00; Y; Y10; Y10S; Y10S438/00; Y10S438/977
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
116 words
A method of thinning a portion of a workpiece, which comprises the steps of: depositing a fluid in a cavity; positioning the face of the workpiece on the fluid to leave no space between the face of the workpiece and the fluid; retaining the workpiece in the cavity with an apertured member, whereby the face is masked by the fluid and a portion of the backside of the workpiece opposite the face is masked by the member; and treating through the aperture of the member the unmasked backside of the workpiece to remove at least a portion of such workpiece, while the masked face and the masked portion of the backside of the workpiece remain untreated.
Claim 2
Independent Claim
116 words
A method of thinning a portion of a workpiece, which comprises the steps of: depositing a fluid in a cavity; positioning the face of the workpiece on the fluid to leave no space between the face of the workpiece and the fluid; retaining the workpiece in the cavity with an apertured member, whereby the face is masked by the fluid and a portion of the backside of the workpiece opposite the face is masked by the member; and treating through the aperture of the member the unmasked backside of the workpiece to remove at least a portion of such workpiece, while the masked face and the masked portion of the backside of the workpiece remain untreated.
Claim 3
Dependent Claim
30 words
The method of claim 1, wherein the treating is accomplished by etching through the aperture of the member the unmasked workpiece to remove at least a portion of such workpiece.
Claim 4
Dependent Claim
28 words
The method of claim 1, comprising the further step of optically checking the thickness of the etched workpiece by transmitting infrared radiation through the workpiece and the fluid.
Claim 5
Independent Claim
99 words
A method of protecting a first portion of a workpiece from a deleterious substance, comprising: positioning the first portion of the workpiece on a non-deleterious fluid so as to leave no space between the workpiece and the fluid and to seal the fluid to such first portion; retaining the workpiece on the fluid with a member having an opening; and applying the deleterious substance through the opening to another portion of the workpiece, whereby the non-deleterious fluid sealed to the first portion of the workpiece excludes the deleterious substance from such first portion to thereby protect such first portion.
Claim 6
Independent Claim
99 words
A method of protecting a first portion of a workpiece from a deleterious substance, comprising: positioning the first portion of the workpiece on a non-deleterious fluid so as to leave no space between the workpiece and the fluid and to seal the fluid to such first portion; retaining the workpiece on the fluid with a member having an opening; and applying the deleterious substance through the opening to another portion of the workpiece, whereby the non-deleterious fluid sealed to the first portion of the workpiece excludes the deleterious substance from such first portion to thereby protect such first portion.
Claim 7
Dependent Claim
53 words
The method of claim 4, wherein the non-deleterious fluid is a liquid transparent to infrared radiation, the deleterious substance includes fumes and removes at least a part of the other portion of the workpiece, and the non-deleterious fluid excludes both the deleterious substance and its fumes from the first portion of the workpiece.
Claim 8
Independent Claim
239 words
A method of selectively thinning a portion of a substrate, comprising the steps of: filling a cavity in an etchant-resistant holding device with a quantity of water exceeding the volume of the cavity to form a meniscus of the water at the top of the cavity; positioning the face of the substate on the water; exerting a force on the backside of a substrate opposite its face to force the quantity of the water exceeding the volume of the cavity to flow out of the cavity and over the outer edge of the device to thereby eliminate the meniscus and leave no space between the face and the water and thereby mask the face with the water; force-fitting a resilient, etchant-resistant top member having an aperture therein over the outer edge of the holding device: to tightly engage such member to such device, and to position a portion of the bottom surface of the top member that is adjacent the aperture to overlap and thereby mask an annular area on the backside; and immersing the holding device and the top member with the substrate therebetween in an etchant to etch and thereby thin a central portion of the backside corresponding to the inner area of the aperture of the top member, while the face masked by the water and the annular area on the backside masked by the overlapping surface of the top member are not etched and thinned.
Claim 9
Independent Claim
239 words
A method of selectively thinning a portion of a substrate, comprising the steps of: filling a cavity in an etchant-resistant holding device with a quantity of water exceeding the volume of the cavity to form a meniscus of the water at the top of the cavity; positioning the face of the substate on the water; exerting a force on the backside of a substrate opposite its face to force the quantity of the water exceeding the volume of the cavity to flow out of the cavity and over the outer edge of the device to thereby eliminate the meniscus and leave no space between the face and the water and thereby mask the face with the water; force-fitting a resilient, etchant-resistant top member having an aperture therein over the outer edge of the holding device: to tightly engage such member to such device, and to position a portion of the bottom surface of the top member that is adjacent the aperture to overlap and thereby mask an annular area on the backside; and immersing the holding device and the top member with the substrate therebetween in an etchant to etch and thereby thin a central portion of the backside corresponding to the inner area of the aperture of the top member, while the face masked by the water and the annular area on the backside masked by the overlapping surface of the top member are not etched and thinned.
Claim 10
Dependent Claim
46 words
The method of claim 6, further comprising the steps of: rotating in the etchant an assembly of the holding device and the top member with substrate therebetween about its central axis; and stirring simultaneously the etchant to improve the uniformity of the thinning of the substrate.
Claim 11
Dependent Claim
97 words
The method of claim 7, further comprising the steps of: removing the assembly from the etchant after the central portion of the substrate has been thinned; removing the top member from the outer edge of the holding device to open a vent extending from the cavity to such outer edge to admit atmospheric pressure to the cavity; and removing the substrate from the water in the cavity of the holding device, whereby the admission of atmospheric pressure assists in the removal of the substrate by preventing a partial vacuum from forming between the substrate and the water.
Claim 12
Dependent Claim
216 words
An improved method of making a charge storage device from a semiconductive substrate having a face and a backside opposite the face wherein a diode array is formed on the face, wherein the backside of the substrate is subjected to a thinning operation, wherein the improvement comprises: filling a cavity of a device with a quantity of fluid exceeding the volume of the cavity to form a meniscus of the fluid at the top of the cavity; positioning the face of the substrate on the fluid; exerting a force on the backside of the substrate to force the quantity of fluid exceeding the volume of the cavity to flow out of the cavity to eliminate the meniscus and leave no space between the face of the substrate and the fluid and thereby mask the face with the fluid; mounting a top member having an aperture therein on the holding device to position a portion of the bottom surface of the top member that is adjacent the aperture to overlap such backside to thereby mask an annular area on the backside corresponding to the overlapping surface; and etching the unmasked portion of the substrate through the aperture in the top member to thin a central portion of the backside corresponding to the inner area of the aperture.
Claim 13
Dependent Claim
216 words
An improved method of making a charge storage device from a semiconductive substrate having a face and a backside opposite the face wherein a diode array is formed on the face, wherein the backside of the substrate is subjected to a thinning operation, wherein the improvement comprises: filling a cavity of a device with a quantity of fluid exceeding the volume of the cavity to form a meniscus of the fluid at the top of the cavity; positioning the face of the substrate on the fluid; exerting a force on the backside of the substrate to force the quantity of fluid exceeding the volume of the cavity to flow out of the cavity to eliminate the meniscus and leave no space between the face of the substrate and the fluid and thereby mask the face with the fluid; mounting a top member having an aperture therein on the holding device to position a portion of the bottom surface of the top member that is adjacent the aperture to overlap such backside to thereby mask an annular area on the backside corresponding to the overlapping surface; and etching the unmasked portion of the substrate through the aperture in the top member to thin a central portion of the backside corresponding to the inner area of the aperture.
Claim 14
Independent Claim
107 words
A method of making an electron beam target, having a face and a backside, comprising the steps of: forming a diode array on the face of a substrate; depositing a fluid in a cavity of a device; positioning the face of the substrate on the fluid to leave no space between the face of the substrate and the fluid; mounting an annular member on the backside of the substrate; and etching the backside of the substrate through the annular member to thin the substrate while the fluid masks the face and a portion of the bottom surface of the annular member masks the backside of the substrate.
Claim 15
Independent Claim
107 words
A method of making an electron beam target, having a face and a backside, comprising the steps of: forming a diode array on the face of a substrate; depositing a fluid in a cavity of a device; positioning the face of the substrate on the fluid to leave no space between the face of the substrate and the fluid; mounting an annular member on the backside of the substrate; and etching the backside of the substrate through the annular member to thin the substrate while the fluid masks the face and a portion of the bottom surface of the annular member masks the backside of the substrate.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-01-05 | 1979-07-07 | 1980-01-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-01-05 | 1983-07-07 | 1984-01-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-01-05 | 1987-07-07 | 1988-01-06 | $7700.00 | Window Closed / Lapsed |