US4866008A
Expired / Lapsed
US
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Methods for forming self-aligned conductive pillars on interconnects
Assignee: Texas Instruments Inc
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Filing: 1987-12-11
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Granted: 1989-09-12
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Expires: 2007-12-11
Abstract
Abstract Methods, of forming a self-aligned conductive pillar (16) on an interconnect (12) on a body (10) having semiconducting surfaces. A first mask (24) defines an inverse pattern for formation of an interconnect (12). The interconnect (12) is formed by additive metallization processes. A second mask (26) is formed over portions of the first mask (24) and the interconnect (12). Sidewalls of the first mask (24) which define at least one side of side of said interconnect (12) serve to also define at least one side of said conductive pillar (16). The second mask (26) also defines at least one side of the conductive pillar (16). The conductive pillar (16) is formed by additive metal deposition processes. The conductive pillar (16) is thus self-aligned to the interconnect (12) on which it is formed. A cladding layer of tungsten (40) can be used on the multiple layers of seed layer (22), e.g. molybdenum coated with thin copper, of copper interconnects (12/14), and of conductive pillars (16/18). Feed layer of nickel and gold interconnect are also disclosed.
Inventors
- 👤 Jeffrey E. Brighton
- 👤 Bobby A. Roane
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 03:21
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/40; H10W20/41; H10W20/42; H10W20/01; H10W20/031; H10W20/032; H10W20/038; H10W20/039; H10W20/063; H10W20/064; H10W20/069; H10W20/0693
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
166 words
A method of forming a self-aligned conductive pillar on a metal interconnect on a body having semiconducting surfaces, the method comprising: forming a first mask on said body, said first mask defining an inverse pattern for the formation of an interconnect on said body; forming a metal interconnect on said body in the pattern defined by said first mask; forming a second mask on said body, said second mask covering at least a portion of said first mask and also covering a portion of said metal interconnect, said second mask providing a space directly over a portion of said metal interconnect for forming said self-aligned conductive pillar, said second mask defining an inverse pattern for forming at least one side of said self-aligned conductive pillar; said inverse pattern of said first mask defining at least one side of said conductive pillar to be formed; and forming said self aligned conductive pillar in said space of said second mask directly over a portion of said metal interconnect.
Claim 2
Independent Claim
166 words
A method of forming a self-aligned conductive pillar on a metal interconnect on a body having semiconducting surfaces, the method comprising: forming a first mask on said body, said first mask defining an inverse pattern for the formation of an interconnect on said body; forming a metal interconnect on said body in the pattern defined by said first mask; forming a second mask on said body, said second mask covering at least a portion of said first mask and also covering a portion of said metal interconnect, said second mask providing a space directly over a portion of said metal interconnect for forming said self-aligned conductive pillar, said second mask defining an inverse pattern for forming at least one side of said self-aligned conductive pillar; said inverse pattern of said first mask defining at least one side of said conductive pillar to be formed; and forming said self aligned conductive pillar in said space of said second mask directly over a portion of said metal interconnect.
Claim 3
Dependent Claim
41 words
The method of claim 1, wherein said conductive pillar is formed to a height above said interconnect not greater than the height above said interconnect of the wall of said first mask which defines at least one side of said pillar.
Claim 4
Dependent Claim
14 words
The method of claim 2, wherein said interconnect and said conductive pillar comprise copper.
Claim 5
Dependent Claim
50 words
The method of claim 1, wherein at least one side of said conductive pillar is self-aligned with said interconnect, at least one side of said conductive pillar being defined by the same sidewalls of said first mask which define the sides of said interconnect which are below said conductive pillar.
Claim 6
Dependent Claim
15 words
The method of claim 1, wherein said conductive pillar is formed by a lift-off process.
Claim 7
Dependent Claim
28 words
The method of claim 2, wherein said first mask and said interconnect are formed on a seed layer on said body, which seed layer comprises a conductive metal.
Claim 8
Dependent Claim
48 words
The method of claim 1, wherein said conductive pillar formed over a portion of said metal interconnect has a vertical height above the surface of said body which is less than the vertical height of the sidewall of said first mask which is adjacent to said conductive pillar.
Claim 9
Dependent Claim
15 words
The method of claim 1, wherein said metal interconnect and said conductive pillar comprise copper.
Claim 10
Dependent Claim
11 words
The method of claim 1, wherein said metal interconnect comprises gold.
Claim 11
Dependent Claim
22 words
The method of claim 1, wherein said interconnect and said conductive pillar are each formed on said body by an electroplating process.
Claim 12
Dependent Claim
13 words
The method of claim 1, wherein said first and second masks comprise photoresist.
Claim 13
Dependent Claim
28 words
The method of claim 1, wherein said first mask and said interconnect are formed on a seed layer on said body, which seed layer comprises a conductive metal.
Claim 14
Dependent Claim
104 words
The method of claim 12, further comprising: removing said first and second masks after said step of forming said conductive pillar; removing portions of said seed layer not covered by said interconnect; forming a layer of isolation material on said body, said layer of isolation material covering said interconnect with at least a portion of said conductive pillar exposed at the surface of said layer of isolation material; and forming a second interconnect on said body, said second interconnect being formed over said layer of isolation material, and said second interconnect also making electrical contact with at least a portion of said conductive pillar.
Claim 15
Dependent Claim
15 words
The method of claim 13, wherein said layer of isolation material comprises a dielectric material.
Claim 16
Dependent Claim
104 words
The method of claim 6, further comprising: removing said first and second masks after said step of forming said conductive pillar; removing portions of said seed layer not covered by said interconnect; forming a layer of isolation material on said body, said layer of isolation material covering said interconnect with at least a portion of said conductive pillar exposed at the surface of said layer of isolation material; and forming a second interconnect on said body, said second interconnect being formed over said layer of isolation material, and said second interconnect also making electrical contact with at least a portion of said conductive pillar.
Claim 17
Independent Claim
209 words
A method of forming a conductive pillar on a metal interconnect on a body having semiconducting surfaces, the method comprising: forming a seed layer on a surface of said body; forming a first mask on said seed layer; forming a metal interconnect in a region defined by said first mask on said seed layer; forming a second mask on said body, said second mask covering a portion of said interconnect and a portion of said first mask, said second mask defining a first side of said conductive pillar which first side is over said interconnect; said first mask having sidewalls defining said interconnect to be formed, and also defining a second side of said conducting pillar to be formed, said sidewalls having a height at the location of formation of said interconnect and said second side of said pillar sufficient to define said second side of said pillar above said interconnect; forming said conductive pillar; removing said second mask and said first mask; etching away portions of said seed layer exposed after removal of said first mask; and forming an isolation layer over said body, including over said interconnect, but allowing at least a portion of said conductive pillar to be exposed at the surface of said isolation layer.
Claim 18
Independent Claim
209 words
A method of forming a conductive pillar on a metal interconnect on a body having semiconducting surfaces, the method comprising: forming a seed layer on a surface of said body; forming a first mask on said seed layer; forming a metal interconnect in a region defined by said first mask on said seed layer; forming a second mask on said body, said second mask covering a portion of said interconnect and a portion of said first mask, said second mask defining a first side of said conductive pillar which first side is over said interconnect; said first mask having sidewalls defining said interconnect to be formed, and also defining a second side of said conducting pillar to be formed, said sidewalls having a height at the location of formation of said interconnect and said second side of said pillar sufficient to define said second side of said pillar above said interconnect; forming said conductive pillar; removing said second mask and said first mask; etching away portions of said seed layer exposed after removal of said first mask; and forming an isolation layer over said body, including over said interconnect, but allowing at least a portion of said conductive pillar to be exposed at the surface of said isolation layer.
Claim 19
Dependent Claim
21 words
The method of claim 16, wherein said seed layer comprises a layer of a refractory metal and a layer of copper.
Claim 20
Dependent Claim
17 words
The method of claim 16, wherein said interconnect comprises copper and wherein said conductive pillar comprises copper.
Claim 21
Dependent Claim
19 words
The method of claim 18, further comprising cladding wherein said interconnect and said conducting pillar with a refractory metal.
Claim 22
Dependent Claim
13 words
The method of claim 17, wherein said layer of refractory metal comprises molybdenum.
Claim 23
Dependent Claim
11 words
The method of claim 16, wherein said first mask comprises photoresist.
Claim 24
Dependent Claim
11 words
The method of claim 21, wherein said second mask comprises photoresist.
Claim 25
Dependent Claim
29 words
The method of claim 16, further comprising: forming a second interconnect over said isolation layer, said second interconnect providing electrical contact between said conductive pillar and said second interconnect.
Claim 26
Dependent Claim
18 words
The method of claim 16, wherein said interconnect and said conductive pillar are formed by an electroplating process.
Claim 27
Dependent Claim
11 words
The method of claim 19, wherein said refractory metal comprises tungsten.
Claim 28
Dependent Claim
19 words
The method of claim 16, wherein said seed layer comprises a layer of nickel and said interconnect comprises gold.
Claim 29
Dependent Claim
20 words
The method of claim 16, wherein second side of said conductive pillar is aligned with a side of said interconnect.
Claim 30
Dependent Claim
36 words
The method of claim 16, wherein the height of said conductive pillar above said seed layer is less than the height of the sidewall of said first mask which defines a side of said conductive pillar.
References Cited (Backward Citations)
US4434544A
Cited
US4652336A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-09-11 | 1993-03-13 | 1993-09-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-09-11 | 1997-03-13 | 1997-09-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-09-11 | 2001-03-13 | 2001-09-12 | $7700.00 | Window Closed / Lapsed |