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US5939334A
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System and method of selectively cleaning copper substrate surfaces, in-situ, to remove copper oxides
Assignee: Sharp Corp
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Filing: 1997-05-22
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Granted: 1999-08-17
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Expires: 2017-05-22
Abstract
Abstract A system and method of selectively etching copper surfaces free of copper oxides in preparation for the deposition of an interconnecting metallic material is provided. The method removes metal oxides with β-diketones, such as Hhfac. The Hhfac is delivered into the system in vapor form, and reacts almost exclusively to copper oxides. The by-products of the cleaning process are likewise volatile for removal from the system with a vacuum pressure. Since the process is easily adaptable to most IC process systems, it can be conducted in an oxygen-free environment, without the removal of the IC from the process chamber. The in-situ cleaning process permits a minimum amount of copper oxide to reform before the deposition of the overlying interconnection metal. In this manner, a highly conductive electrical interconnection between the copper surface and the interconnecting metal material is formed. An IC having a metal interconnection, in which the underlying copper layer is cleaned of copper oxides, in-situ with Hhfac vapor, is also provided.
Inventors
- 👤 Tue Nguyen
- 👤 Lawrence J. Charneski
- 👤 David R. Evans
- 👤 Sheng Teng Hsu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 15:25
CPC Classifications
C; C23; C23G; C23G5/00; H; H10; H10P; H10P50/00; H10P50/20; H10P50/28; H10P50/282; H10P50/283; H10P50/286; H10P50/287; H10P50/60; H10P50/66; H10P50/663; H10P50/667; H10P70/00; H10P70/20; H10P70/23; H10P70/234; H10W; H10W20/00; H10W20/01; H10W20/031; H10P70/27
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
138 words
In an integrated circuit (IC) having a dielectric interlevel with a dielectric surface, and a plurality of metal levels underlying the dielectric interlevel, a method for selectively cleaning metal oxides, in-situ, from a surface on a first metal level, accessed through a via from the dielectric surface, the method comprising the steps of: a) providing an atmosphere surrounding the integrated circuit; b) controlling the atmosphere to be substantially free of oxygen, whereby the formation of metal oxides on the first metal level surface is minimized; c) introducing a β-diketone vapor into the atmosphere; and d) volatilizing the metal oxides from the first metal level surface using the β-diketone vapor introduced in step c), whereby a minimal amount of material is removed from the first metal level surface in preparation for an electrical connection with subsequently deposited metal levels.
Claim 2
Dependent Claim
138 words
In an integrated circuit (IC) having a dielectric interlevel with a dielectric surface, and a plurality of metal levels underlying the dielectric interlevel, a method for selectively cleaning metal oxides, in-situ, from a surface on a first metal level, accessed through a via from the dielectric surface, the method comprising the steps of: a) providing an atmosphere surrounding the integrated circuit; b) controlling the atmosphere to be substantially free of oxygen, whereby the formation of metal oxides on the first metal level surface is minimized; c) introducing a β-diketone vapor into the atmosphere; and d) volatilizing the metal oxides from the first metal level surface using the β-diketone vapor introduced in step c), whereby a minimal amount of material is removed from the first metal level surface in preparation for an electrical connection with subsequently deposited metal levels.
Claim 3
Dependent Claim
23 words
A method as in claim 1 wherein the first metal level is a metal selected from the group consisting of copper and silver.
Claim 4
Dependent Claim
66 words
A method as in claim 1 in which step c) includes using a β-diketone having the following structural formula: ##STR1## in which the R and R 1 groups are selected from the set of groups consisting of C1 to C6 alkyls, perfluoroalkyls, and other substitutions, and the X group is selected from the functional groups consisting of H, F, CL, Br, I, alkyls, perfluoroalkyls, and substitutions.
Claim 5
Dependent Claim
28 words
A method as in claim 3 in which step c) includes using hexafluoroacetylacetonate (Hifac) as the β-diketone to volatilize the metal oxides on the first metal level surface.
Claim 6
Dependent Claim
30 words
A method as in claim 4 in which step c) includes delivering the Hhfac at a pressure of less than approximately 85 Torr and a temperature of approximately 20° C.
Claim 7
Dependent Claim
44 words
A method as in claim 1 including the further step, following step d), of: e) creating a vacuum to remove the volatile metal oxides obtained in step d) from the atmosphere, whereby the cleaning by-products are easily removed from the area of the IC.
Claim 8
Dependent Claim
29 words
A method as in claim 1 including the further step, before step c), of: f) controlling the IC temperature to be in the range between 100 and 450° C.
Claim 9
Dependent Claim
52 words
A method as in claim 1 including the further step, following step d), of: g) while maintaining the atmosphere established in step b), depositing a second metal level overlying the first metal level surface to electrically interface to the first metal level, whereby the cleaning process facilitates a low resistance electrical connection.
Claim 10
Dependent Claim
48 words
A method as in claim 8 in which step g) includes depositing a second metal level selected from the group consisting of TiN, TiSi x N y , TaSi x N y , TaN, WN, WSi x N y , Ti, Ta, W, Cu, Al, Ag, and Au.
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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) | 2002-08-16 | 2003-02-15 | 2003-08-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-08-16 | 2007-02-15 | 2007-08-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-08-16 | 2011-02-15 | 2011-08-17 | $7700.00 | Window Closed / Lapsed |