US4544576A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Deep dielectric isolation by fused glass
Assignee: International Business Machines Corp
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Filing: 1981-07-27
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Granted: 1985-10-01
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Expires: 2001-07-27
Abstract
Abstract Deep dielectric isolation zones in a substrate are achieved by forming trenches using reactive ion etching. A glass having a coefficient of thermal expansion closely matching that of the substrate is deposited onto the trench to entirely or partially fill the trench. Deposition can be by sedimentation, centrifugation or spin-on techniques. The structure is then fired until the glass particles fuse into a continuous glass layer and final smoothing if necessary can be accomplished.
Inventors
- 👤 Wei-Kan Chu
- 👤 William A. Pliskin
- 👤 Jacob Riseman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 05:40
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/60; H10P14/69; H10P14/692; H10P14/6921; H10P14/6922; H10P14/63; H10P14/6326; H10P14/6342; H10P14/65; H10P14/6502; H10P14/6506; H10P95/00; H10P95/06; H10W; H10W10/00; H10W10/01; H10W10/011; H10W10/014; H10W10/10; H10W10/17; Y; Y10; Y10S; Y10S438/00; Y10S438/942; Y10S438/948; Y10S438/951
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
82 words
A method for forming high density dielectric isolation in an integrated circuit structure comprising the steps of: forming trenches having substantially vertical sidewalls in a silicon substrate; filling the trenches with suspension containing particles of glass having a coefficient of thermal expansion substantially the same as the substrate; firing the structure at a temperature high enough to fuse the particles of glass and to form a continuous glass layer in the trenches; and simultaneously planarizing the surface of said integrated circuit structure.
Claim 2
Independent Claim
82 words
A method for forming high density dielectric isolation in an integrated circuit structure comprising the steps of: forming trenches having substantially vertical sidewalls in a silicon substrate; filling the trenches with suspension containing particles of glass having a coefficient of thermal expansion substantially the same as the substrate; firing the structure at a temperature high enough to fuse the particles of glass and to form a continuous glass layer in the trenches; and simultaneously planarizing the surface of said integrated circuit structure.
Claim 3
Dependent Claim
30 words
The method of claim 1, wherein the step of forming trenches comprises reactive ion etching trenches in said substrate having sidewalls substantially perpendicular to a top surface of said substrate.
Claim 4
Dependent Claim
50 words
The method of claim 1, further comprising the steps of mixing a finely ground glass powder having properties matching said silicon substrate with a high dielectric constant fluid, adding a lower dielectric constant fluid and mixing, centrifuging to separate coarse particles from the resulting suspension and, decanting the resulting suspension.
Claim 5
Independent Claim
24 words
The method of claims 1 or 3, wherein the step of filling the trenches comprises sedimenting multiple layers of said suspension into said trenches.
Claim 6
Independent Claim
21 words
The method of claims 1 or 2, wherein the step of filling the trenches comprises sedimenting said suspension into said trenches.
Claim 7
Independent Claim
23 words
The method of claims 1 or 2, wherein the step of filling the trenches comprises centrifugal deposition of said suspension into said trenches.
Claim 8
Dependent Claim
20 words
The method of claim 4, wherein the step of firing comprises firing the structure following each sedimentation of said suspension.
Claim 9
Dependent Claim
24 words
The method of claim 3, further comprising the step of applying a heavier and lower dielectric constant fluid underneath said suspension prior to centrifugation.
Claim 10
Independent Claim
47 words
The method of claims 1 or 3, further comprising the steps of depositing a thin oxide film on said substrate prior to forming said trenches, forming said trenches by reactive ion etching and growing a thermal oxide lining for said trenches prior to filling by glass sedimentation.
Claim 11
Dependent Claim
51 words
The method of claim 9, further comprising the steps of depositing a film of a material not reactive to either said oxide film or said substrate on top of said oxide film prior to forming said trenches and, lifting off said film and any glass deposited thereon to planarize said surface.
Claim 12
Dependent Claim
26 words
The method of claim 10, further comprising the step of applying a thin layer of glass of chemical vapor deposition to smooth and fill said surface.
Claim 13
Dependent Claim
12 words
The method of claim 10, wherein said material is a metal film.
Claim 14
Dependent Claim
24 words
The method of claim 9, wherein the step of planarizing comprises the step of reactive ion etching to remove glass particles from said surface.
Claim 15
Dependent Claim
54 words
The method of claim 9, further comprising the step of applying a heavier and lower dielectric constant fluid in a sedimenting vessel and underneath said suspension prior to filling and wherein the step of filling results in a void in the bottom of said trenches with a plug of glass formed over said trench.
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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) | 1988-09-30 | 1989-04-01 | 1989-10-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-09-30 | 1993-04-01 | 1993-10-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-09-30 | 1997-04-01 | 1997-10-01 | $7700.00 | Window Closed / Lapsed |