US4599792A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Buried field shield for an integrated circuit
Assignee: International Business Machines Corp
•
Filing: 1984-06-15
•
Granted: 1986-07-15
•
Expires: 2004-06-15
Abstract
Abstract A method for fabrication of a buried field shield in a semiconductor substrate. A seed substrate is prepared by depositing an epitaxial layer or a seed wafer and then depositing a heavily doped layer and a thin dielectric. The thin dielectric is patterned for contact holes and then a conductive field shield is deposited and patterned. A thick quartz layer is deposited over the field shield and dielectric. A mechanical substrate is anodically bonded to the quartz of the seed substrate and the original seed wafer is etched back to expose the epitaxial layer for further fabrication.
Inventors
- 👤 Paul E. Cade
- 👤 Badih El-Kareh
- 👤 Ick W. Kim
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 21:11
CPC Classifications
H; H10; H10D; H10D86/00; H10D86/01; H10P; H10P90/00; H10P90/19; H10P90/1904; H10P90/1906; H10P90/1914; H10W; H10W10/00; H10W10/10; H10W10/181; H10W15/00; H10W15/01; H10W20/00; H10W20/01; H10W20/021; H10W42/00; H10W72/00; H10W72/30; H10W72/071; H10W72/073; H10W72/07331; H10W72/07337; Y; Y10; Y10S; Y10S148/00; Y10S148/025; Y10S148/05; Y10S148/135
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
109 words
A method of fabricating a semiconductor structure, comprising the steps of: depositing an epitaxial semiconductor layer on a first semiconductor substrate; forming and patterning a first dielectric layer overlying said epitaxial layer; forming a field shield layer of a conductive material on predetermined portions of said first dielectric layer and on predetermined portions of said epitaxial layer; covering said field shield layer and all exposed portions of said first dielectric layer and said epitaxial layer with a bonding material; bonding a second substrate to the side of said first substrate covered with said bonding material, thereby forming a bonded structure; and removing said first substrate from said bonded structure.
Claim 2
Independent Claim
109 words
A method of fabricating a semiconductor structure, comprising the steps of: depositing an epitaxial semiconductor layer on a first semiconductor substrate; forming and patterning a first dielectric layer overlying said epitaxial layer; forming a field shield layer of a conductive material on predetermined portions of said first dielectric layer and on predetermined portions of said epitaxial layer; covering said field shield layer and all exposed portions of said first dielectric layer and said epitaxial layer with a bonding material; bonding a second substrate to the side of said first substrate covered with said bonding material, thereby forming a bonded structure; and removing said first substrate from said bonded structure.
Claim 3
Dependent Claim
51 words
A method of fabricating a semiconductor structure as recited in claim 1, further comprising the step of: forming on said first substrate before the depositing of said epitaxial layer an etch stopping layer; and wherein said removing step is an etching step that does not substantially etch said etch stopping layer.
Claim 4
Dependent Claim
38 words
A method of fabricating a semiconductor structure as recited in claim 2, wherein; said step of forming an etch stopping layer includes patterning said layer to exclude aligning areas; and said etching step is an anisotropic etching step.
Claim 5
Dependent Claim
28 words
A method of fabricating a semiconductor structure, as recited in claim 1, wherein said removing step is an etching step that does not substantially etch said epitaxial layer.
Claim 6
Dependent Claim
68 words
A method of fabricating a semiconductor structure as recited in claim 4, wherein the conductivity type of said epitaxial layer is n-type and the doping concentration of said epitaxial layer is equal to or less than 10 18 /cm 3 ; and the conductivity type of said first substrate is p-type and the doping concentration of said first substrate is substantially greater than 10 18 /cm 3 .
Claim 7
Dependent Claim
22 words
A method of fabricating a semiconductor structure as recited in claim 5, wherein said etching step uses an etchant of hydrofluoric-nitric-acetic acid.
Claim 8
Dependent Claim
81 words
A method of fabricating a semiconductor structure as recited in claim 1, further comprising the step of: forming on said epitaxial layer, before the forming and patterning of said dielectric layer, an emitter layer of a semiconductor of the same conductivity type as said epitaxial layer and having a doping concentration substantially larger than the doping concentration of said epitaxial layer; wherein said patterning of said first dielectric layer includes an etching step that does not substantially etch said emitter layer.
Claim 9
Dependent Claim
82 words
A method of fabricating a semiconductor structure as recited in claim 6, further comprising the step of: forming on said epitaxial layer, before the forming and patterning of said dielectric layer, an emitter layer of a semiconductor of the same conductivity type as said epitaxial layer and having a doping concentration substantially larger than the doping concentration of said epitaxial layer; and wherein said patterning of said first dielectric layer includes an etching step that does not substantially etch said emitter layer.
Claim 10
Dependent Claim
27 words
A method of forming a semiconductor, as recited in claim 4, further comprising scribing alignment marks on said first substrate before said bonding steps with a laser.
Claim 11
Dependent Claim
27 words
A method of forming a semiconductor, as recited in claim 8, further comprising scribing alignment marks on said first substrate before said bonding steps with a laser.
References Cited (Backward Citations)
US3846198A
Cited
US3959045A
Cited
US4089021A
Cited
US4404737A
Cited
US4290831A
Cited
US4408386A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-07-14 | 1990-01-13 | 1990-07-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-07-14 | 1994-01-13 | 1994-07-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-07-14 | 1998-01-13 | 1998-07-15 | $7700.00 | Window Closed / Lapsed |