US5466331A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Elevated thin film for ceramic materials
Assignee: Texas Instruments Inc
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Filing: 1994-04-04
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Granted: 1995-11-14
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Expires: 2014-04-04
Abstract
Abstract A novel reticulated array comprises islands of ceramic (e.g. BST 20) which are fabricated from novel materials using unique methods of patterning. Trenches (22) are formed in the ceramic substrate from the front side and filled with a filler material (e.g. parylene 24). An elevation layer (e.g. polyimide 26) is deposited above the filler material, and a front side optical coating (e.g. transparent metal layer 34, transparent organic layer 36 and conductive metallic layer 38 ) is elevated above the substrate between the ceramic islands. The elevation layer provides added protection to the optical coating during filler material removal. The substrate is thinned from the back side down through a portion of the trench filler material. Novel fabrication methods also provide for the convenient electrical and mechanical bonding of each of the massive number of ceramic islands to a signal processor substrate (e.g. Si 62) containing a massive array of sensing circuits.
Inventors
- 👤 James F. Belcher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 08:49
CPC Classifications
H; H10; H10F; H10F39/00; H10F39/10; H10F39/12; H10F39/15; H10F39/157; H10F39/1575
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
187 words
A method of forming a microelectronic structure, said method comprising steps: (a) providing a ceramic substrate having a front side and a back side; (b) forming trenches having a depth and a first pattern on said front side of said ceramic substrate; (c) filling said trenches with a filler material; (d) forming an elevation layer having a second pattern on said front side of said substrate, said elevation layer substantially aligned with said trenches and covering at least said filler material in said trenches; (e) depositing a thin front layer on said front side of said substrate and on said elevation layer, thereby forming elevated portions of said thin front layer above said front side; (f) thinning said ceramic substrate by mechanically polishing said back side of said ceramic substrate to a thickness less than said depth of said trenches; (g) removing said filler material from said trenches; and (h) removing said elevation layer, thereby forming isolated islands of said ceramic substrate connected by said thin front layer, whereby the thin front layer remains substantially undamaged, having not been exposed to the removing process of step (g).
Claim 2
Independent Claim
187 words
A method of forming a microelectronic structure, said method comprising steps: (a) providing a ceramic substrate having a front side and a back side; (b) forming trenches having a depth and a first pattern on said front side of said ceramic substrate; (c) filling said trenches with a filler material; (d) forming an elevation layer having a second pattern on said front side of said substrate, said elevation layer substantially aligned with said trenches and covering at least said filler material in said trenches; (e) depositing a thin front layer on said front side of said substrate and on said elevation layer, thereby forming elevated portions of said thin front layer above said front side; (f) thinning said ceramic substrate by mechanically polishing said back side of said ceramic substrate to a thickness less than said depth of said trenches; (g) removing said filler material from said trenches; and (h) removing said elevation layer, thereby forming isolated islands of said ceramic substrate connected by said thin front layer, whereby the thin front layer remains substantially undamaged, having not been exposed to the removing process of step (g).
Claim 3
Dependent Claim
14 words
The method according to claim 1, wherein said ceramic substrate is barium strontium titanate.
Claim 4
Dependent Claim
13 words
The method according to claim 1, said step (b) further comprising laser vaporization.
Claim 5
Dependent Claim
33 words
The method according to claim 3, said step (b) further comprising: surface etching said front side of said ceramic substrate and annealing said ceramic substrate in a oxygen ambient after said laser vaporization.
Claim 6
Dependent Claim
28 words
The method according to claim 1, said step (c) further comprising: planarizing said filler material and said front side of said substrate after said filling of said trenches.
Claim 7
Dependent Claim
24 words
The method according to claim 1, wherein said filler material is selected from the group consisting of: photoresist, oxide, polyimide, parylene, epoxy, and nitride.
Claim 8
Dependent Claim
36 words
The method according to claim 1, said method further comprising depositing a protective metal layer on said front side of said ceramic substrate and on said filler material before said step of forming said elevation layer.
Claim 9
Dependent Claim
13 words
The method according to claim 7, wherein said protective metal layer is TiW.
Claim 10
Dependent Claim
53 words
The method according to claim 1, said step (d) further comprising: depositing a first organic layer on said front side of said substrate; forming a first mask layer on said first organic layer; etching said first organic layer to form said elevation layer having said second pattern; and removing said first mask layer.
Claim 11
Dependent Claim
13 words
The method according to claim 9, wherein said first mask layer is photoresist.
Claim 12
Dependent Claim
33 words
The method according to claim 1, wherein said elevation layer is a different material than said filler material, and said elevation layer is selected from the group consisting of: photoresist, parylene, and polyimide.
Claim 13
Dependent Claim
64 words
The method according to claim 1, wherein said thin front layer comprises multiple layers, and said step of depositing said thin front layer further comprises: depositing a conductive metallic layer on said front side of said substrate and on said elevation layer; depositing a transparent organic layer on said conductive metallic layer; and depositing a thin transparent metal layer on said transparent organic layer.
Claim 14
Dependent Claim
27 words
The method according to claim 12, wherein said conductive metallic layer is NiCr, said transparent organic layer is parylene, and said thin transparent metal layer is NiCr.
Claim 15
Dependent Claim
44 words
The method according to claim 1, wherein a top surface of said thin front layer opposite said ceramic substrate is mounted to a removable carrier after said step of depositing said thin front layer, wherein said carrier provides mechanical support for subsequent process steps.
Claim 16
Dependent Claim
30 words
The method according to claim 1, said method further comprising forming thin electrical contacts on said back side of said ceramic substrate after said step of thinning said ceramic substrate.
Claim 17
Dependent Claim
13 words
The method according to claim 15, wherein said islands form infrared sensitive capacitors.
Claim 18
Dependent Claim
19 words
The method according to claim 15, wherein said thin electrical contacts comprise two or more layers, and comprise indium.
Claim 19
Dependent Claim
79 words
The method according to claim 15, said step of forming thin electrical contacts further comprising: forming a second mask layer on said back side of said substrate, said second mask layer substantially aligned with said filler material in said trenches; depositing an electrical contact layer on said back side of said substrate and on said second mask layer; and lifting off said second mask layer to remove a portion of said electrical contact layer on said second mask layer.
Claim 20
Dependent Claim
13 words
The method according to claim 18, wherein said second mask layer is photoresist.
Claim 21
Dependent Claim
20 words
The method according to claim 1, wherein said elevation layer is removed with a wet solvent or a dry etch.
Claim 22
Dependent Claim
17 words
The method according to claim 1, wherein said islands of said ceramic substrate form a reticulated array.
Claim 23
Dependent Claim
15 words
The method according to claim 21, wherein said microelectronic structure is an infrared radiation detector.
Claim 24
Dependent Claim
32 words
The method according to claim 1, said method further comprising bump bonding said back side of said ceramic substrate to a signal processing substrate after said step of removing said elevation layer.
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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) | 1998-11-13 | 1999-05-15 | 1999-11-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-11-13 | 2003-05-15 | 2003-11-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-11-13 | 2007-05-15 | 2007-11-14 | $7700.00 | Window Closed / Lapsed |