US4641420A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Metalization process for headless contact using deposited smoothing material
Assignee: Nokia Bell Labs
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Filing: 1984-08-30
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Granted: 1987-02-10
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Expires: 2004-08-30
Abstract
Abstract Contacting an underlying region (e.g., doped silicon) through an access hole in an overlying dielectric layer (e.g., p-glass) formerly required flowing the dielectric to smooth the edges of the hole, so that aluminum would deposit smoothly into the hole. The present technique smoothes the side of the hole by forming a smoothing region on the sidewall. Improved aluminum coverage results, as well as allowing a smaller contact head, if desired. Improved contact resistance can be optionally provided by depositing a more conductive layer on the underlying layer prior to forming the sidewall.
Inventors
- 👤 Kuo-Hua Lee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 19:57
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/01; H10W20/071; H10P; H10P14/00; H10P14/60; H10P14/66; H10P14/668; H10P14/6681; H10P14/6684; H10P14/6686; H10P14/69; H10P14/692; H10P14/6921; H10P14/69215; H10W20/031; H10W20/056; H10W20/074; H10W20/076; H10W20/081; H10W20/082; H10W20/40; Y; Y10; Y10S; Y10S148/00; Y10S148/019; Y10S148/02; Y10S148/043; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12535
Claims Analysis
Total Claims: 41
Claim 1
Independent Claim
127 words
A method of making an article including the step of making an electrical contact to an underlying doped semiconductor region by steps comprising forming an opening in an overlying dielectric material, characterized by the further steps of thereafter forming a layer of a material that is more conductive than said doped semiconductor region on said doped semiconductor region, conformally depositing a dielectric smoothing material onto the more conductive layer and the sidewall of said opening, removing the dielectric smoothing material from the central portion of the more conductive layer while maintaining a smoothing region of the dielectric smoothing material in contact with the sidewall of the opening, and depositing conducting material at least onto the central portion of the more conductive layer and onto the smoothing region.
Claim 2
Independent Claim
127 words
A method of making an article including the step of making an electrical contact to an underlying doped semiconductor region by steps comprising forming an opening in an overlying dielectric material, characterized by the further steps of thereafter forming a layer of a material that is more conductive than said doped semiconductor region on said doped semiconductor region, conformally depositing a dielectric smoothing material onto the more conductive layer and the sidewall of said opening, removing the dielectric smoothing material from the central portion of the more conductive layer while maintaining a smoothing region of the dielectric smoothing material in contact with the sidewall of the opening, and depositing conducting material at least onto the central portion of the more conductive layer and onto the smoothing region.
Claim 3
Dependent Claim
12 words
The method of claim 1 wherein said smoothing material is silicon dioxide.
Claim 4
Dependent Claim
12 words
The method of claim 1 wherein said smoothing material is silicon nitride.
Claim 5
Dependent Claim
27 words
The method of claim 1 wherein said smoothing material as deposited has a thickness at least 0.4 as much as the thickness of said overlying dielectric material.
Claim 6
Dependent Claim
13 words
The method of claim 1 wherein said dielectric material is a flowable glass.
Claim 7
Dependent Claim
32 words
The method of claim 5 wherein said flowable glass is flowed at an elevated temperature so as to smooth at least one step of said article prior to said forming said opening.
Claim 8
Dependent Claim
14 words
The method of claim 1 wherein the more conductive layer substantially comprises a metal.
Claim 9
Dependent Claim
24 words
The method of claim 7 wherein said metal selectively deposits preferentially onto said doped semiconductor region as compared to onto said overlying dielectric material.
Claim 10
Dependent Claim
10 words
The method of claim 7 wherein said metal is tungsten.
Claim 11
Dependent Claim
10 words
The method of claim 1 wherein said semiconductor is silicon.
Claim 12
Dependent Claim
13 words
The method of claim 10 wherein the more conductive layer is a silicide.
Claim 13
Dependent Claim
17 words
The method of claim 11 wherein said silicide substantially comprises silicon derived from said doped semiconductor region.
Claim 14
Dependent Claim
13 words
The method of claim 1 wherein the deposited conducting material is a metal.
Claim 15
Dependent Claim
10 words
The method of claim 13 wherein said metal is aluminum.
Claim 16
Dependent Claim
14 words
The method of claim 13 wherein said depositing said metal is accomplished by sputtering.
Claim 17
Independent Claim
130 words
A method of making an article including the step of making an electrical contact to an underlying metal layer by steps comprising forming an opening in an overlying dielectric material, characterized by the further steps of conformally depositing a dielectric smoothing material onto said underlying metal layer and the sidewall of said opening, with said smoothing material as deposited having a thickness of at least 0.4 as much as the thickness of said dielectric material, and thereafter anisotropically removing said smoothing material from the central portion of said underlying metal layer while maintaining a smoothing region of said smoothing material in contact with the sidewall of said opening, and thereafter depositing a metal layer at least onto the central portion of said underlying metal layer and onto the smoothing region.
Claim 18
Independent Claim
130 words
A method of making an article including the step of making an electrical contact to an underlying metal layer by steps comprising forming an opening in an overlying dielectric material, characterized by the further steps of conformally depositing a dielectric smoothing material onto said underlying metal layer and the sidewall of said opening, with said smoothing material as deposited having a thickness of at least 0.4 as much as the thickness of said dielectric material, and thereafter anisotropically removing said smoothing material from the central portion of said underlying metal layer while maintaining a smoothing region of said smoothing material in contact with the sidewall of said opening, and thereafter depositing a metal layer at least onto the central portion of said underlying metal layer and onto the smoothing region.
Claim 19
Dependent Claim
12 words
The method of claim 16 wherein said smoothing material is silicon dioxide.
Claim 20
Dependent Claim
12 words
The method of claim 16 wherein said smoothing material is silicon nitride.
Claim 21
Dependent Claim
26 words
The method of claim 16 wherein said smoothing material as depsoited has a thickness of less than 1.5 of the thickness of said overlying dielectric material.
Claim 22
Dependent Claim
12 words
The method of claim 16 wherein said underlying metal layer is aluminum.
Claim 23
Dependent Claim
12 words
The method of claim 16 wherein the deposited metal layer is aluminum.
Claim 24
Dependent Claim
15 words
The method of claim 16 wherein said depositing a metal layer is accomplished by sputtering.
Claim 25
Dependent Claim
9 words
An article made by the method of claim 16.
Claim 26
Independent Claim
127 words
A method of making an article including the step of making an electrical contact to an underlying region by steps comprising forming an opening in an overlying dielectric material, characterized by the further steps of thereafter forming a layer of a material that is more conductive than said underlying region on said underlying region, wherein the more conductive material substantially comprises a metal, conformally depositing a dielectric smoothing material onto the more conductive layer and the sidewall of said opening, and anisotropically removing said smoothing material from the central portion of the more conductive layer while maintaining a smoothing region of said smoothing material in contact with the sidewall of said opening, and thereafter despositing a conductor at least onto siad central portion and said smoothing region.
Claim 27
Independent Claim
127 words
A method of making an article including the step of making an electrical contact to an underlying region by steps comprising forming an opening in an overlying dielectric material, characterized by the further steps of thereafter forming a layer of a material that is more conductive than said underlying region on said underlying region, wherein the more conductive material substantially comprises a metal, conformally depositing a dielectric smoothing material onto the more conductive layer and the sidewall of said opening, and anisotropically removing said smoothing material from the central portion of the more conductive layer while maintaining a smoothing region of said smoothing material in contact with the sidewall of said opening, and thereafter despositing a conductor at least onto siad central portion and said smoothing region.
Claim 28
Dependent Claim
12 words
The method of claim 24 wherein said smoothing material is silicon dioxide
Claim 29
Dependent Claim
17 words
The method of claim 25 wherein said silicon dioxide is deposited by low pressure chemical vapor deposition.
Claim 30
Dependent Claim
11 words
The method of claim 24 wherein said conductor substantially comprises aluminum.
Claim 31
Dependent Claim
12 words
The method of claim 27 wherein said aluminum is deposited by sputtering.
Claim 32
Dependent Claim
28 words
The method of claim 24 wherein the thickness of said smoothing material as deposited is at least 0.4 as much as the thickness of said overlying dielectric material.
Claim 33
Independent Claim
111 words
A method of making an article including the step of making an electrical contact to an underlying region by steps comprising forming an opening having a substantially straight sidewall in an overlying dielectric material. characterized by the further steps of conformally depositing a smoothing material onto said underlying region and the sidewall of said opening, anisotropically removing said smoothing material from the central portion of said underlying region while maintaining a smoothing region of said smoothing material in contact with said sidewall, and thereafter sputtering a metal at least onto the central portion of said underlying region and onto the smoothing region, wherein said underlying region is a metal silicide. region.
Claim 34
Independent Claim
111 words
A method of making an article including the step of making an electrical contact to an underlying region by steps comprising forming an opening having a substantially straight sidewall in an overlying dielectric material. characterized by the further steps of conformally depositing a smoothing material onto said underlying region and the sidewall of said opening, anisotropically removing said smoothing material from the central portion of said underlying region while maintaining a smoothing region of said smoothing material in contact with said sidewall, and thereafter sputtering a metal at least onto the central portion of said underlying region and onto the smoothing region, wherein said underlying region is a metal silicide. region.
Claim 35
Dependent Claim
10 words
The method of claim 30 wherein said metal is aluminum.
Claim 36
Dependent Claim
19 words
The method of claim 30 wherein said metal silicide is formed on the surface of a doped semiconductor region.
Claim 37
Dependent Claim
14 words
The method of claim 30 wherein said overlying dielectric material includes a flowable glass.
Claim 38
Dependent Claim
32 words
The method of claim 33 wherein said flowable glass is flowed at an elevated temperature so as to smooth at least one step of said article prior to said forming said opening.
Claim 39
Dependent Claim
27 words
The method of claim 30 wherein said smoothing material as deposited has a thickness at least 0.4 as much as the thickness of said overlying dielectric material.
Claim 40
Dependent Claim
12 words
The method of claim 30 wherein said smoothing material is silicon dioxide
Claim 41
Dependent Claim
17 words
The method of claim 36 wherein said silicon dioxide is deposited by low pressure chemical vapor deposition.
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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) | 1990-02-09 | 1990-08-11 | 1991-02-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-02-09 | 1994-08-11 | 1995-02-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-02-09 | 1998-08-11 | 1999-02-10 | $7700.00 | Window Closed / Lapsed |