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US5143867A
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Method for depositing interconnection metallurgy using low temperature alloy processes
Assignee: International Business Machines Corp
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Filing: 1991-02-13
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Granted: 1992-09-01
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Expires: 2011-02-13
Abstract
Abstract A method for filling VLSI high aspect ratio vias and lines in VLSI interconnection structures, with a low resistivity metal at temperatures below 400° C. A low melting point alloy of a desired low resistivity metal is deposited into the high aspect ratio vias or lines. The alloy is then purified in place by bringing the alloying element to the surface of the deposited alloy and removing the element from said surface thereby leaving the low resistivity metal in the interconnection structure. In one embodiment, the alloy is purified by using a low temperature oxidation process to allow the alloying element to diffuse to the surface of the deposited alloy where a surface oxide is formed. The surface oxide is then removed by chemical etching or by chemical mechanical polishing. In a second embodiment, a continuous exposure to a plasma etching or reactive ion etching will steadily remove the alloying element from the surface of the deposited alloy. In a third embodiment, the deposited alloy is planarized and then a sink layer is deposited onto the planarized interconnection structure. The structure is annealed in order to allow the alloying element to diffuse into the sink layer. The sink layer is then removed by chemical mechanical polishing.
Inventors
- 👤 Francois M. D'Heurle
- 👤 James M. E. Harper
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:56
CPC Classifications
H; H10; H10P; H10P95/00; H10P52/00; H10P52/40; H10P52/403; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/056; Y; Y10; Y10S; Y10S148/00; Y10S148/13
Claims Analysis
Total Claims: 36
Claim 1
Independent Claim
102 words
A method for filling a VLSI high aspect ratio recess in an interconnection structure defined in a dielectric layer disposed on one main planar surface of a substrate with a metal comprising the steps of: (a) providing a low melting point alloy of a metal and an alloying element; (b) depositing said alloy into the recess of the interconnection structure at a deposition temperature which is below the alloy melting point; (c) purifying said alloy by diffusing the alloying element to a surface layer formed on said dielectric layer and removing said surface layer, thereby leaving the metal in the interconnection structure.
Claim 2
Independent Claim
102 words
A method for filling a VLSI high aspect ratio recess in an interconnection structure defined in a dielectric layer disposed on one main planar surface of a substrate with a metal comprising the steps of: (a) providing a low melting point alloy of a metal and an alloying element; (b) depositing said alloy into the recess of the interconnection structure at a deposition temperature which is below the alloy melting point; (c) purifying said alloy by diffusing the alloying element to a surface layer formed on said dielectric layer and removing said surface layer, thereby leaving the metal in the interconnection structure.
Claim 3
Dependent Claim
16 words
The method of claim 1, wherein said alloy has a melting point below about 600° C.
Claim 4
Dependent Claim
26 words
The method of claim 1, wherein said metal is a low resistivity metal comprising a metal selected from the group consisting of gold, silver and copper.
Claim 5
Dependent Claim
34 words
The method of claim 1, wherein said alloying element comprises an element selected from the group consisting of silicon, germanium, lead, aluminum, calcium, antimony, cerium, europium, lanthanum, lithium, magnesium, barium, selenium, strontium and tellurium.
Claim 6
Dependent Claim
51 words
The method of claim 1, wherein said metal comprises a metal selected from the group consisting of gold, silver and copper and wherein said alloying element comprises an element selected from the group consisting of silicon, germanium, lead, aluminum, calcium, antimony, cerium, europium, lanthanum, lithium, magnesium, barium, selenium, strontium and tellurium.
Claim 7
Dependent Claim
16 words
The method of claim 1, wherein said depositing step comprises depositing said alloy by bias sputtering.
Claim 8
Dependent Claim
14 words
The method of claim 1, wherein said deposition temperature is below about 400° C.
Claim 9
Dependent Claim
31 words
The method of claim 1, wherein said purifying step includes oxidizing the element thereby diffusing the element to a surface of the surface layer in the form of a surface oxide.
Claim 10
Dependent Claim
23 words
The method of claim 8, wherein said purifying step includes chemical etching the surface oxide thereby removing the alloying element from the structure.
Claim 11
Dependent Claim
24 words
The method of claim 8, wherein said purifying step includes chemical mechanical polishing the surface oxide thereby removing the alloying element from the structure.
Claim 12
Dependent Claim
40 words
The method of claim 1, wherein said purifying step includes continually exposing the structure to plasma etching thereby simultaneously segregating the alloying element to a surface of said surface layer and removing the segregated alloying element from the surface layer.
Claim 13
Dependent Claim
40 words
The method of claim 1, wherein said purifying step includes continually exposing the structure to reactive ion etching thereby simultaneously segregating the alloying element to a surface of said surface layer and removing the segregated element from the surface layer.
Claim 14
Dependent Claim
16 words
The method of claim 9, further including the step of planarizing the surface of said structure.
Claim 15
Dependent Claim
16 words
The method of claim 11, further including the step of planarizing the surface of said structure.
Claim 16
Dependent Claim
16 words
The method of claim 12, further including the step of planarizing the surface of said structure.
Claim 17
Dependent Claim
21 words
The method of claim 13, wherein said planarizing step comprises removing excess material on the dielectric layer by chemical mechanical polishing.
Claim 18
Dependent Claim
21 words
The method of claim 14, wherein said planarizing step comprises removing excess material on the dielectric layer by chemical mechanical polishing.
Claim 19
Dependent Claim
21 words
The method of claim 15, wherein said planarizing step comprises removing excess material on the dielectric layer by chemical mechanical polishing.
Claim 20
Dependent Claim
47 words
The method of claim 1, wherein said purifying step comprises the steps of: (a) planarizing said dielectric layer; (b) depositing a sink layer onto the planarized dielectric layer; (c) annealing the structure thereby diffusing the alloying element into the sink layer; and (d) removing the sink layer.
Claim 21
Dependent Claim
15 words
The method of claim 19, wherein the dielectric layer is planarized by chemical mechanical polishing.
Claim 22
Dependent Claim
13 words
The method of claim 19, wherein said sink layer is deposited by evaporation.
Claim 23
Dependent Claim
13 words
The method of claim 19, wherein said sink layer is deposited by sputtering.
Claim 24
Dependent Claim
15 words
The method of claim 19, wherein said sink layer is deposited by chemical vapor deposition.
Claim 25
Dependent Claim
17 words
The method of claim 19, wherein said structure is annealed at a temperature below about 400° C.
Claim 26
Dependent Claim
13 words
The method of claim 19, wherein the sink layer is removed by chemical-mechanical-polishing.
Claim 27
Dependent Claim
22 words
The method of claim 19, wherein the sink layer comprises a metal selected from the group consisting of gold, silver and copper.
Claim 28
Independent Claim
70 words
A method for purifying an alloy of a metal and an alloy element deposited in an interconnection structure defined in a dielectric layer disposed on one main planar surface of a substrate comprising the steps of: (a) planarizing the dielectric layer; (b) depositing a sink layer onto the planarized dielectric layer; (c) annealing the structure thereby diffusing the alloy element into the sink layer; and (d) removing the sink layer.
Claim 29
Independent Claim
70 words
A method for purifying an alloy of a metal and an alloy element deposited in an interconnection structure defined in a dielectric layer disposed on one main planar surface of a substrate comprising the steps of: (a) planarizing the dielectric layer; (b) depositing a sink layer onto the planarized dielectric layer; (c) annealing the structure thereby diffusing the alloy element into the sink layer; and (d) removing the sink layer.
Claim 30
Dependent Claim
15 words
The method of claim 27, wherein the dielectric layer is planarized by chemical mechanical polishing.
Claim 31
Dependent Claim
13 words
The method of claim 27, wherein said sink layer is deposited by evaporation.
Claim 32
Dependent Claim
13 words
The method of claim 27, wherein said sink layer is deposited by sputtering.
Claim 33
Dependent Claim
15 words
The method of claim 27, wherein said sink layer is deposited by chemical vapor deposition.
Claim 34
Dependent Claim
17 words
The method of claim 27, wherein said structure is annealed at a temperature below about 400° C.
Claim 35
Dependent Claim
15 words
The method of claim 27, wherein said sink layer is removed by chemical mechanical polishing.
Claim 36
Dependent Claim
22 words
The method of claim 27, wherein the sink layer comprises a metal selected from the group consisting of gold, silver and copper.
References Cited (Backward Citations)
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) | 1995-09-01 | 1996-03-02 | 1996-09-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-09-01 | 2000-03-02 | 2000-09-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-09-01 | 2004-03-02 | 2004-09-01 | $7700.00 | Window Closed / Lapsed |