Patent US4533430A successfully refreshed from Google Patents.
US4533430A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for forming slots having near vertical sidewalls at their upper extremities
Assignee: RPX Corp
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Filing: 1984-01-04
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Granted: 1985-08-06
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Expires: 2004-01-04
Abstract
Abstract A slot formation process is provided in which the regions near the mouth of the slot are coated, while the slot is being formed, with a material which is resistant to the etchant being used to form the slot. The coating may be applied continuously or may be applied at specific points in the slot formation process. During the formation of the middle and bottom regions of the slot the coated upper regions retain a nearly vertical contour shape since they are protected from undesired etching by ions whose trajectories have been impacted by charge accumulations at the mouth of the slot. The coating material may be a thin oxide layer of the semiconductor material or may be a layer of an appropriate etch resistant material.
Inventors
- 👤 Robert W. Bower
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 13:15
CPC Classifications
H; H10; H10P; H10P50/00; H10P50/20; H10P50/24; H10P50/242; H10P50/69; H10P50/691; H10P50/693; H10P50/694; H10W; H10W10/00; H10W10/01; H10W10/011; H10W10/014; H10W10/0145; H10W10/0148; H10W10/041; H10W10/10; H10W10/17; H10W10/40
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
111 words
A process for fabricating slots in a wafer of semiconductor material wherein the slots have nearly vertical sidewalls near the mouth of the slot, comprising the steps of: applying an etch-resistant mask material to the surface of said wafer of semiconductor material; patterning said mask material to expose regions in said substrate in which slots are to be formed; etching said exposed regions in said substrate to form said slots; and forming an etch resistant coating on the walls of said slots while they are being formed whereby said etch resistant coating protects said sidewalls near the mouth of the slot from unwanted etching so they retain a nearly vertical shape.
Claim 2
Dependent Claim
111 words
A process for fabricating slots in a wafer of semiconductor material wherein the slots have nearly vertical sidewalls near the mouth of the slot, comprising the steps of: applying an etch-resistant mask material to the surface of said wafer of semiconductor material; patterning said mask material to expose regions in said substrate in which slots are to be formed; etching said exposed regions in said substrate to form said slots; and forming an etch resistant coating on the walls of said slots while they are being formed whereby said etch resistant coating protects said sidewalls near the mouth of the slot from unwanted etching so they retain a nearly vertical shape.
Claim 3
Dependent Claim
47 words
A process for fabricating slots in accordance with claim 1 wherein said step of forming an etch resistant coating is accomplished by the step of supplying a partial pressure of oxygen in the chamber in which said wafer is being etched while said slots are being formed.
Claim 4
Dependent Claim
71 words
A process for fabricating slots in accordance with claim 1 wherein said step of etching said exposed regions comprises the step of etching said exposed regions in said substrate until said slots are partially formed and wherein said step of forming an etch resistant coating is accomplished by the step of: treating the surface of said partially formed slot to form an etch resistant coating after said slots are partially formed.
Claim 5
Dependent Claim
42 words
A process for fabricating slots in accordance with claim 3 wherein said step of treating said surface of said partially formed slot is accomplished by the step of thermally oxidizing the exposed surface of the semiconductor material in said partially formed slot.
Claim 6
Dependent Claim
42 words
A process for fabricating slots in accordance with claim 3 wherein said step of treating the surface of said partially formed slot is accomplished by the step of exposing the surface of said partially formed slots to a solution of hydrogen peroxide.
Claim 7
Dependent Claim
55 words
A process for fabricating slots in accordance with claim 5 wherein said step of exposing the surface of said partially formed slots to a solution of hydrogen peroxide is accomplished by the step of exposing the surface of said partially formed slots to a 30% solution of hydrogen peroxide in water for about ten minutes.
Claim 8
Dependent Claim
41 words
A process for fabricating slots in accordance with claim 3 wherein said step of treating the surface of said partially formed slot is accomplished by the step of applying a layer of etch resistant material by low pressure chemical vapor deposition.
Claim 9
Dependent Claim
43 words
A process for fabricating slots in accordance with claim 7 wherein said step of applying a layer of etch resistant material by low pressure chemical vapor deposition comprises the step of applying a layer of silicon nitride by low pressure chemical vapor deposition.
Claim 10
Dependent Claim
46 words
A process for fabricating slots in accordance with claim 3 wherein said step of etching said exposed regions in said substrate until said slots are partially formed is accomplished by the step of etching said exposed regions to a depth of less than about one micron.
Claim 11
Dependent Claim
41 words
A process for fabricating slots in accordance with any one of claims 3-9 wherein after said step of treating the surface of said partially formed slot the following step is carried out: etching said partially formed slot to a desired depth.
Claim 12
Dependent Claim
60 words
A process for fabricating slots in accordance with claim 10 wherein after said step of etching said partially formed slot to a desired depth the following steps are carried out: forming an etch resistant coating on the sidewalls of said slot at least adjacent the mouth of said slot; and etching the as formed slot to an additional desired depth.
Claim 13
Dependent Claim
78 words
A process for fabricating slots in accordance with claim 10 wherein after said step of etching said partially formed slot to a desired depth the following steps are carried out: filling said slot with a material which substantially fills the volume of the slot and conforms to the contours of the slot; and etching the surface of said wafer to remove excess filler material and expose a planar surface suitable for serving as a foundation for overlying layers.
Claim 14
Dependent Claim
60 words
A process for fabricating slots in accordance with claim 12 wherein after said step of etching said surface of said wafer to remove excess filler material the following steps are followed: applying a layer of passivating material to the surface of said wafer; and applying a conductive metal layer over portiqns of the surface of said layer of passivating material.
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) | 1988-08-05 | 1989-02-04 | 1989-08-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-08-05 | 1993-02-04 | 1993-08-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-08-05 | 1997-02-04 | 1997-08-06 | $7700.00 | Window Closed / Lapsed |