US5730835A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Facet etch for improved step coverage of integrated circuit contacts
Assignee: Micron Technology Inc
•
Filing: 1996-01-31
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Granted: 1998-03-24
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Expires: 2016-01-31
Abstract
Abstract Disclosed is a method for providing improved step coverage of contacts with conductive materials, and particularly metals. A conductive layer is deposited over an insulating layer, either before or after contact opening formation. After both conductive layer deposition and contact formation, a facet etch is performed to slope the conductive layer overlying the contact lip while depositing material from the conductive layer into the lower corner of the contact, where coverage has traditionally been poor. A second conductive layer may then be deposited into the contact to supplement coverage provided by the first conductive layer and the facet etch.
Inventors
- 👤 Ceredig Roberts
- 👤 Anand Srinivasan
- 👤 Gurtej Sandhu
- 👤 Sujit Sharan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 23:48
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/032; H10W20/054; H10W20/033; H10W20/052; H10W20/0523; H10W20/056; H10W20/0595; H10W20/40; H10W20/41; H10W20/425; H10W20/034
Claims Analysis
Total Claims: 39
Claim 1
Independent Claim
60 words
A method of forming a contact lined with a conductive material, the method comprising the steps of: forming an insulating layer over a partially fabricated integrated circuit; forming a contact through the insulating layer, the contact exposing an underlying circuit element; depositing a first conductive layer over the insulating layer; and forming a facet over a lip of the contact.
Claim 2
Independent Claim
60 words
A method of forming a contact lined with a conductive material, the method comprising the steps of: forming an insulating layer over a partially fabricated integrated circuit; forming a contact through the insulating layer, the contact exposing an underlying circuit element; depositing a first conductive layer over the insulating layer; and forming a facet over a lip of the contact.
Claim 3
Dependent Claim
14 words
The method of claim 1, wherein the facet forming step comprises a facet etch.
Claim 4
Dependent Claim
19 words
The method of claim 2, wherein the facet etch deposits conductive material from the conductive layer into the contact.
Claim 5
Dependent Claim
19 words
The method of claim 3, wherein the facet etch deposits conductive material into a lower corner of the contact.
Claim 6
Dependent Claim
42 words
The method of claim 1, wherein the step of depositing the first conductive layer is performed prior to the contact forming step, and further comprising the step of depositing a second conductive layer over the first conductive layer and into the contact.
Claim 7
Dependent Claim
42 words
The method of claim 5, wherein the insulating layer has a depth between about 2,000 and 30,000 Å, the contact has a diameter between about 2,000 and 8,000, and the second conductive layer has a thickness between about 1,000 and 10,000 Å.
Claim 8
Dependent Claim
25 words
The method of claim 5, wherein the contact forming step comprises performing a plasma etch through both the first conductive layer and the insulating layer.
Claim 9
Dependent Claim
28 words
The method of claim 5, wherein the contact forming step comprises a chlorine etch of the first conductive layer and a fluorocarbon plasma etch of the insulating layer.
Claim 10
Dependent Claim
29 words
The method of claim 1, wherein the step of depositing the first conductive layer is performed after the contact forming step, and the first conductive layer lines the contact.
Claim 11
Dependent Claim
45 words
The method of claim 9, wherein the insulating layer has a depth between about 2,000 and 30,000 Å, the contact has a diameter between about 2,000 Å and 8,000 Å, and the first conductive layer has a thickness between about 500 Å and 2,000 Å.
Claim 12
Dependent Claim
25 words
The method of claim 9, wherein the contact forming step comprises etching through the insulating layer and stopping the etch on the underlying circuit element.
Claim 13
Dependent Claim
22 words
The method of claim 9, further comprising the step of depositing a second conductive layer into the contact after the facet etch.
Claim 14
Dependent Claim
19 words
The method of claim 1, wherein the step of depositing the first conductive layer comprises a metal sputter deposition.
Claim 15
Dependent Claim
14 words
The method of claim 13, wherein the first conductive layer comprises a titanium layer.
Claim 16
Dependent Claim
15 words
The method of claim 14, further comprising the step of depositing a second conductive layer.
Claim 17
Dependent Claim
14 words
The method of claim 15, wherein the second conductive layer comprises an aluminum layer.
Claim 18
Dependent Claim
18 words
The method of claim 16, wherein the second conductive layer further comprises between about 0.5 and 4.0% copper.
Claim 19
Dependent Claim
15 words
The method of claim 2, wherein the facet etch comprises a substantially non-reactive, physical etch.
Claim 20
Dependent Claim
14 words
The method of claim 18, wherein the facet etch comprises an ion milling step.
Claim 21
Dependent Claim
22 words
The method of claim 19, wherein the ion milling step comprises bombarding the wafer surface with a plurality of noble gas ions.
Claim 22
Dependent Claim
15 words
The method of claim 20, wherein the ion milling step comprises an argon sputter etch.
Claim 23
Dependent Claim
41 words
The method of claim 21, wherein the argon sputter etch comprises maintaining an rf power between about 300 and 1,000 W, a pressure between about 5 mTorr and 40 mTorr and an argon flow between about 10 sccm and 100 sccm.
Claim 24
Independent Claim
121 words
A method of forming an interconnect layer in an integrated circuit while forming contact to an underlying circuit element, the method comprising: etching a contact through an interlevel insulating layer to expose the circuit element, the contact having a lip surrounding an upper boundary and a lower corner surrounding a lower boundary; depositing a first conductive material to form a first conductive layer over the insulating layer; performing a facet etch preferentially etching the first conductive material from a corner of the first conductive layer over the contact lip, and sputtering the etched material into the lower corner; depositing a second conductive material to form a second conductive layer over the insulating layer and into the contact after the facet etch.
Claim 25
Independent Claim
121 words
A method of forming an interconnect layer in an integrated circuit while forming contact to an underlying circuit element, the method comprising: etching a contact through an interlevel insulating layer to expose the circuit element, the contact having a lip surrounding an upper boundary and a lower corner surrounding a lower boundary; depositing a first conductive material to form a first conductive layer over the insulating layer; performing a facet etch preferentially etching the first conductive material from a corner of the first conductive layer over the contact lip, and sputtering the etched material into the lower corner; depositing a second conductive material to form a second conductive layer over the insulating layer and into the contact after the facet etch.
Claim 26
Dependent Claim
67 words
The method of claim 23, wherein the step of depositing the first conductive material comprises depositing the material into the contact to a thickness less than half the thickness of a diameter of the contact, the first conductive layer forming electrical contact with the exposed circuit element; and the step of depositing the second conductive material comprises depositing the second conductive layer superjacent the first conductive layer.
Claim 27
Dependent Claim
27 words
The method of claim 24, wherein the second conductive material is deposited conformally over the first conductive layer to a thickness insufficient to completely fill the contact.
Claim 28
Dependent Claim
24 words
The method of claim 22, wherein the step of depositing the first conductive material is performed prior to the step of etching the contact.
Claim 29
Independent Claim
56 words
A method of at least partially filling a contact through an insulating layer, the method comprising: depositing a first conductive layer over the insulating layer and into the contact; performing a facet etch on the conductive layer; and depositing a second conductive layer over the insulating layer and superjacent the first conductive layer in the contact.
Claim 30
Independent Claim
56 words
A method of at least partially filling a contact through an insulating layer, the method comprising: depositing a first conductive layer over the insulating layer and into the contact; performing a facet etch on the conductive layer; and depositing a second conductive layer over the insulating layer and superjacent the first conductive layer in the contact.
Claim 31
Dependent Claim
18 words
The method of claim 27, wherein the first and second conductive layer deposition steps comprise metal sputter depositions.
Claim 32
Independent Claim
63 words
A method of providing metal coverage on a sidewall and a bottom surface of a contact in an insulating layer, the method comprising: sputtering a metal layer over the insulating layer; forming a conductive annular corner fill over the contact bottom surface and proximate the sidewall; and depositing a supplemental metal later over the annular corner fill, the sidewall and the bottom surface.
Claim 33
Independent Claim
63 words
A method of providing metal coverage on a sidewall and a bottom surface of a contact in an insulating layer, the method comprising: sputtering a metal layer over the insulating layer; forming a conductive annular corner fill over the contact bottom surface and proximate the sidewall; and depositing a supplemental metal later over the annular corner fill, the sidewall and the bottom surface.
Claim 34
Dependent Claim
17 words
The method of claim 29, wherein the contact has a diameter of less than about 8,000 Å.
Claim 35
Dependent Claim
17 words
The method of claim 28, wherein the contact has an aspect ratio of greater than about 1.0.
Claim 36
Dependent Claim
111 words
An integrated circuit having a contact between a circuit element and an interconnect level, the integrated circuit comprising: an insulating layer superjacent the circuit element, the insulating layer having a contact therethrough and a top surface, the contact defined by a sidewall and a bottom surface, the contact sidewall and the insulating layer top surface meeting at a contact lip; a first metal layer superjacent the insulating layer top surface and lining the contact sidewall, the first metal layer comprising an annular corner fill over the contact bottom surface and proximate the sidewall; and a second metal layer superjacent the first metal layer and lining the contact sidewall and bottom surface.
Claim 37
Dependent Claim
111 words
An integrated circuit having a contact between a circuit element and an interconnect level, the integrated circuit comprising: an insulating layer superjacent the circuit element, the insulating layer having a contact therethrough and a top surface, the contact defined by a sidewall and a bottom surface, the contact sidewall and the insulating layer top surface meeting at a contact lip; a first metal layer superjacent the insulating layer top surface and lining the contact sidewall, the first metal layer comprising an annular corner fill over the contact bottom surface and proximate the sidewall; and a second metal layer superjacent the first metal layer and lining the contact sidewall and bottom surface.
Claim 38
Dependent Claim
19 words
The integrated circuit of claim 32, wherein the first metal layer has a sloped facet over the contact lip.
Claim 39
Dependent Claim
28 words
The integrated circuit of claim 32, wherein the first metal layer lines the contact sidewall and bottom surface, electrically contacting the circuit element at the contact bottom surface.
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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) | 2001-03-23 | 2001-09-22 | 2002-03-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-03-23 | 2005-09-22 | 2006-03-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-03-23 | 2009-09-22 | 2010-03-24 | $7700.00 | Window Closed / Lapsed |