Patent US5238529A successfully refreshed from Google Patents.
US5238529A
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Anisotropic metal oxide etch
Assignee: Texas Instruments Inc
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Filing: 1992-04-20
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Granted: 1993-08-24
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Expires: 2012-04-20
Abstract
Abstract A metal oxide substrate (e.g. barium strontium titanate 34) is immersed in a liquid ambient (e.g. 12 molar concentration hydrochloric acid 30) and illuminated with radiation (e.g. collimated visible/ultraviolet radiation 24) produced by a radiation source (e.g. a 200 Watt mercury zenon arc lamp 20). A window 26 which is substantially transparent to the collimated radiation 24 allows the radiated energy to reach the metal oxide substrate 34. An etch mask 32 may be positioned between the radiation source 20 and the substrate 34. The metal oxide substrate 34 and liquid ambient 30 are maintained at a nominal temperature (e.g. 25 DEG C.). Without illumination, the metal oxide is not appreciably etched by the liquid ambient. Upon illumination the etch rate is substantially increased.
Inventors
- 👤 Monte A. Douglas
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 16:09
CPC Classifications
H; H10; H10D; H10D1/00; H10D1/60; H10D1/68; H10D1/682; C; C04; C04B; C04B41/00; C04B41/53; C04B41/5338; C04B41/5353; C04B41/80; C04B41/91; G; G03; G03F; G03F7/00; G03F7/20; G03F7/2041; H10P; H10P50/00; H10P50/20; H10P50/28; H10P50/282; H10P50/283
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
82 words
A method to anisotropically etch a metal oxide material comprising the steps of (a) submersing a surface of said metal oxide material in a non-alkaline liquid ambient; and (b) illuminating portions of said surface with radiation, wherein said illuminated portions of said surface are chemically etched at a substantially greater rate than the unilluminated portions of said surface, and said illuminated portions of said surface are at a temperature substantially the same as the temperature of said unilluminated portions of said surface.
Claim 2
Independent Claim
82 words
A method to anisotropically etch a metal oxide material comprising the steps of (a) submersing a surface of said metal oxide material in a non-alkaline liquid ambient; and (b) illuminating portions of said surface with radiation, wherein said illuminated portions of said surface are chemically etched at a substantially greater rate than the unilluminated portions of said surface, and said illuminated portions of said surface are at a temperature substantially the same as the temperature of said unilluminated portions of said surface.
Claim 3
Dependent Claim
36 words
The method according to claim 1, wherein said illuminated portions of said surface are chemically etched due to electronic excitation caused by photo-irradiation in a reaction between said metal oxide material and said non-alkaline liquid ambient.
Claim 4
Dependent Claim
22 words
The method according to claim 1, wherein said liquid ambient is comprised of hydrochloric acid or hydrofluoric acid or a combination thereof.
Claim 5
Dependent Claim
17 words
The method according to claim 1, wherein said radiation is produced by a mercury xenon arc lamp.
Claim 6
Dependent Claim
14 words
The method according to claim 1, wherein said metal oxide material is a titanate.
Claim 7
Dependent Claim
13 words
The method according to claim 5, wherein said titanate is barium strontium titanate.
Claim 8
Dependent Claim
20 words
The method according to claim 1, wherein the direction of propagation of said radiation is substantially orthogonal to said surface.
Claim 9
Dependent Claim
29 words
The method according to claim 1, wherein an etch mask is interposed between the source of said radiation and said surface whereby portions of said surface are not illuminated.
Claim 10
Dependent Claim
13 words
The method according to claim 8, wherein said etch mask is silicon oxide.
Claim 11
Dependent Claim
13 words
The method according to claim 8, wherein said etch mask is silicon nitride.
Claim 12
Dependent Claim
14 words
The method according to claim 8, wherein said etch mask is a noble metal.
Claim 13
Dependent Claim
12 words
The method according to claim 11, wherein said noble metal is platinum.
Claim 14
Dependent Claim
12 words
The method according to claim 1, wherein said liquid ambient is acidic.
Claim 15
Dependent Claim
16 words
The method according to claim 1, wherein said liquid ambient is comprised of a salt solution.
Claim 16
Dependent Claim
34 words
The method according to claim 1, wherein said metal oxide material comprises barium strontium titanate, said non-alkaline liquid ambient comprises 12 molar hydrochloric acid, and said radiation is produced by a mercury/xenon arc lamp.
Claim 17
Independent Claim
81 words
A method to anisotropically etch a metal oxide material comprising the steps of (a) submersing a surface of said metal oxide material in a liquid ambient; and (b) illuminating portions of said surface with radiation, wherein said illuminated portions of said surface are chemically etched at a substantially greater rate than the unilluminated portions of said surface, and said illuminated portions of said surface are at a temperature substantially the same as the temperature of said unilluminated portions of said surface.
Claim 18
Independent Claim
81 words
A method to anisotropically etch a metal oxide material comprising the steps of (a) submersing a surface of said metal oxide material in a liquid ambient; and (b) illuminating portions of said surface with radiation, wherein said illuminated portions of said surface are chemically etched at a substantially greater rate than the unilluminated portions of said surface, and said illuminated portions of said surface are at a temperature substantially the same as the temperature of said unilluminated portions of said surface.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1996-08-23 | 1997-02-22 | 1997-08-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-08-23 | 2001-02-22 | 2001-08-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-08-23 | 2005-02-22 | 2005-08-24 | $7700.00 | Window Closed / Lapsed |