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US6071808A
Expired / Lapsed
US
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Method of passivating copper interconnects in a semiconductor
Assignee: Nokia of America Corp
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Filing: 1999-06-23
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Granted: 2000-06-06
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Expires: 2019-06-23
Abstract
Abstract A method of passivating copper interconnects is disclosed. A freshly electrodeposited copper interconnect such as formed as via/trench structures in semiconductor manufacturing is chemically converted to passivating surface of copper tungstate or copper chromate either through MOCVD reaction with vapors of tungsten or chromium alkoxides, or by pyrolytic reaction with tungsten or chromium carbonyl in the presence of O 2 . The copper interconnect having the formed passivation service is then chemically mechanically polished. The process can be used with various manufacturing processes, including single and dual damascene processes.
Inventors
- 👤 Sailesh M. Merchant
- 👤 Sudhanshu Misra
- 👤 Pradip K. Roy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:56
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/01; H10D64/011; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/032; H10W20/055; H10P; H10P52/00; H10P52/40; H10P52/403; H10P95/00; H10W20/033; H10W20/037; H10P50/00; H10P50/60; H10P50/66; H10P50/663; H10P50/667
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
167 words
A method of passivating copper interconnects in a semiconductor comprising the steps of: depositing a first oxide layer over a semiconductor substrate; forming an etch stop layer over the oxide layer; forming a second oxide layer over the etch stop layer; etching a first set of trench openings within the second oxide layer and then etching through the etch stop layer; etching a second set of openings in the first oxide layer within the bounds defined by the first set of openings to form vias for interconnects; electrodepositing a copper layer over selected portions of the second oxide layer such that copper is deposited within the first and second sets of openings and forming exposed copper interconnects; exposing the electrodeposited copper interconnects to a chemical reaction containing vapors of tungsten alkoxide and chromium alkoxide in an MOCVD reactor to form respectively copper tungstates and copper chromates as a passivating surface on the exposed copper interconnects; and then chemically mechanically polishing the copper interconnects having the passivating surface.
Claim 2
Independent Claim
167 words
A method of passivating copper interconnects in a semiconductor comprising the steps of: depositing a first oxide layer over a semiconductor substrate; forming an etch stop layer over the oxide layer; forming a second oxide layer over the etch stop layer; etching a first set of trench openings within the second oxide layer and then etching through the etch stop layer; etching a second set of openings in the first oxide layer within the bounds defined by the first set of openings to form vias for interconnects; electrodepositing a copper layer over selected portions of the second oxide layer such that copper is deposited within the first and second sets of openings and forming exposed copper interconnects; exposing the electrodeposited copper interconnects to a chemical reaction containing vapors of tungsten alkoxide and chromium alkoxide in an MOCVD reactor to form respectively copper tungstates and copper chromates as a passivating surface on the exposed copper interconnects; and then chemically mechanically polishing the copper interconnects having the passivating surface.
Claim 3
Dependent Claim
22 words
A method according to claim 1, and further comprising the step of chemically mechanically polishing with a tungsten chemical mechanical polishing process.
Claim 4
Dependent Claim
22 words
A method according to claim 1, and wherein the method further comprises an MOCVD reaction between copper and tungsten or chromium alkoxide.
Claim 5
Dependent Claim
34 words
A method according to claim 3, and wherein said chromium alkoxide precursor is used and the MOCVD reaction is done at elevated temperature ranging from 200° C. to 750° C. to facilitate passivation reaction.
Claim 6
Dependent Claim
39 words
A method according to claim 1, and further comprising the step of initiating a pyrolytic chemical reaction, wherein said pyrolytic chemical reaction comprises pyrolytic breakdown of tungsten and chromium carbonyls forming copper tungstates and chromates upon reaction with copper.
Claim 7
Dependent Claim
40 words
A method according to claim 5, wherein said pyrolytic chemical conversion is conducted at high temperatures ranging from 200° C. to 1100° C. and the use of chromium carbonyl in the presence of excess O 2 to facilitate passivation reaction.
Claim 8
Dependent Claim
22 words
A method according to claim 1, and further comprising the step of forming the etch stop layer as a silicon nitride layer.
Claim 9
Dependent Claim
25 words
A method according to claim 1, and further comprising the step of depositing the copper layer by one of electrodeposition, electroplating or chemical vapor deposition.
Claim 10
Independent Claim
100 words
A method of passivating copper interconnects in a semiconductor comprising the steps of: depositing an oxide layer over a semiconductor substrate; etching an in-laid pattern within the oxide layer; electrodepositing a copper layer within at least the in-laid pattern to form copper interconnects; exposing the electrodeposited copper interconnects to an alkoxide vapor or carbonyl vapor of tungsten or chromium in an MOCVD reactor as an MOCVD reaction to form respectively one of at least copper tungstates and copper chromates as a passivating surface on the exposed copper interconnects; and then chemically mechanically polishing the copper interconnects having the passivation surface.
Claim 11
Independent Claim
100 words
A method of passivating copper interconnects in a semiconductor comprising the steps of: depositing an oxide layer over a semiconductor substrate; etching an in-laid pattern within the oxide layer; electrodepositing a copper layer within at least the in-laid pattern to form copper interconnects; exposing the electrodeposited copper interconnects to an alkoxide vapor or carbonyl vapor of tungsten or chromium in an MOCVD reactor as an MOCVD reaction to form respectively one of at least copper tungstates and copper chromates as a passivating surface on the exposed copper interconnects; and then chemically mechanically polishing the copper interconnects having the passivation surface.
Claim 12
Dependent Claim
22 words
A method according to claim 9, and further comprising the step of chemically mechanically polishing with a tungsten chemical mechanical polishing process.
Claim 13
Dependent Claim
40 words
A method according to claim 9, and wherein said tungsten alkoxide precursor is used and the MOCVD reaction is conducted at an elevated temperature ranging from 200° C. to 750° C. to facilitate the passivation reaction for copper tungstate formation.
Claim 14
Dependent Claim
42 words
A method according to claim 9, wherein a pyrolytic chemical conversion is conducted at elevated temperatures ranging from 200° C. to 1100° C. using tungsten carbonyl in the presence of excess O 2 to facilitate the passivation reaction for copper tungstate formation.
Claim 15
Dependent Claim
22 words
A method according to claim 9, and further comprising the step of forming an etch stop layer as a silicon nitride layer.
Claim 16
Dependent Claim
25 words
A method according to claim 9, and further comprising the step of depositing the copper layer by one of electrodeposition, electroplating or chemical vapor deposition.
Claim 17
Independent Claim
59 words
A method of passivating copper interconnects comprising the steps of: exposing a freshly electrodeposited copper interconnect to a chemical reaction involving vapor phase alkoxides or carbonyls on tungsten and chromium to form respectively copper tungstates and copper chromates as a passivating surface on the exposed copper interconnect; and then chemically mechanically polishing the copper interconnects having the passivation surface.
Claim 18
Independent Claim
59 words
A method of passivating copper interconnects comprising the steps of: exposing a freshly electrodeposited copper interconnect to a chemical reaction involving vapor phase alkoxides or carbonyls on tungsten and chromium to form respectively copper tungstates and copper chromates as a passivating surface on the exposed copper interconnect; and then chemically mechanically polishing the copper interconnects having the passivation surface.
Claim 19
Dependent Claim
22 words
A method according to claim 15, and further comprising the step of chemically mechanically polishing with a tungsten chemical mechanical polishing process.
Claim 20
Dependent Claim
28 words
A method according to claim 15, and further comprising an MOCVD reaction that involves MOCVD reaction with tungsten alkoxide at temperature ranges of 200° C. to 750° C.
Claim 21
Dependent Claim
34 words
A method according to claim 15, and further comprising a pyrolytic reaction that involves chemical conversion in the presence of O 2 using tungsten carbonyl at temperature ranges of 200° C. to 1100° C.
Claim 22
Dependent Claim
28 words
A method according to claim 15, and further comprising an MOCVD reaction that involves MOCVD reaction with chromium alkoxide at temperature ranges of 200° C. to 750° C.
Claim 23
Dependent Claim
36 words
A method according to claim 19, and further comprising a pyrolytic reaction that involves chemical conversion in the presence of chromium carbonyl and excess of O 2 at temperature ranges of 200° C. to 1100° C.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2003-06-06 | 2003-12-06 | 2004-06-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-06-06 | 2007-12-06 | 2008-06-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-06-06 | 2011-12-06 | 2012-06-06 | $7700.00 | Window Closed / Lapsed |