Patent US4624749A successfully refreshed from Google Patents.
US4624749A
Expired / Lapsed
US
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Electrodeposition of submicrometer metallic interconnect for integrated circuits
Assignee: Intersil Corp
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Filing: 1985-09-03
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Granted: 1986-11-25
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Expires: 2005-09-03
Abstract
Abstract Formation of a metallic interconnect pattern in submicron geometry architectures, without the photoresist being lifted off the substrate and resulting in the deposited metal being electroplated therebeneath, is achieved by a combination of a toughened-skin photoresist and pulsed electroplating. For toughening the skin of the photoresist and thereby enhancing its ability to withstand encroachment of the electrodeposited metal, the photoresist layer is illuminated with ultraviolet radiation. After the UV-irradiated photoresist has been allowed to cool, the resulting structure is placed in an electroplating bath, with appropriate electrodes disposed in the bath and connected to a said layer on the wafer for the deposition of the interconnect metal. The electrode differential is pulsed to provide a low frequency plating current through which the conductor metal is plated onto the seed metal on the wafer, as defined by the pattern of the toughened photoresist. After a prescribed, controlled electrodeposition interval during which the interconnect conductor has been plated to a desired level by the pulsed electroplating current, the wafer is removed from the bath and the photoresist layer is etched off, to leave only the electrodeposited interconnect layer and the underlying base (seed) metal. The exposed base metal is then etched leaving only the desired electrodeposited interconnect pattern.
Inventors
- 👤 Jimmy C. Black
- 👤 Bruce E. Roberts
- 👤 Dyer A. Matlock
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 08:17
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/056; H10W20/057; H10P; H10P14/00; H10P14/40; H10P14/46; H10P14/47; H10W20/063; Y; Y10; Y10S; Y10S205/00; Y10S205/918
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
129 words
A method of forming a metallization pattern on the surface of a support structure comprising the steps of: (a) selectively forming a metallization mask over the surface of said support structure, to thereby expose surface regions thereof on which said metallization pattern is to be formed; (b) exposing said mask to electromagnetic radiation so as to effectively increase the rigidity of the surface of said mask and thereby enhance the ability of said mask to resist removal during subsequent electrodeposition of metal onto said surface regions; and (c) immersing the structure obtained in step (b) in an electroplating solution and causing metal to be electrodeposited from said solution onto said surface regions by modulating electroplating current through the flow of which said metal is electrodeposited on said surface regions.
Claim 2
Independent Claim
129 words
A method of forming a metallization pattern on the surface of a support structure comprising the steps of: (a) selectively forming a metallization mask over the surface of said support structure, to thereby expose surface regions thereof on which said metallization pattern is to be formed; (b) exposing said mask to electromagnetic radiation so as to effectively increase the rigidity of the surface of said mask and thereby enhance the ability of said mask to resist removal during subsequent electrodeposition of metal onto said surface regions; and (c) immersing the structure obtained in step (b) in an electroplating solution and causing metal to be electrodeposited from said solution onto said surface regions by modulating electroplating current through the flow of which said metal is electrodeposited on said surface regions.
Claim 3
Dependent Claim
14 words
A method according to claim 1, wherein said support structure comprises a semiconductor device.
Claim 4
Dependent Claim
29 words
A method according to claim 2, wherein step (a) comprises selectively forming a layer of photoresist material patterned apertures through which expose the surface regions of said semiconductor device.
Claim 5
Dependent Claim
21 words
A method according to claim 3, wherein step (b) comprises irradiating said selectively formed layer of photoresist material with ultraviolet light.
Claim 6
Dependent Claim
15 words
A method according to claim 1, wherein step (c) comprises ON-OFF modulating said electroplating current.
Claim 7
Dependent Claim
26 words
A method according to claim 5, wherein the frequency of modulation of said electroplating current lies in a range of from 100 Hz to 1,000 Hz.
Claim 8
Dependent Claim
24 words
A method according to claim 6, wherein the duty cycle of said electroplating current lies in a range of from 5 to 25 percent.
Claim 9
Dependent Claim
40 words
A method according to claim 3, wherein said selectively formed layer of photoresist material is illuminated with ultraviolet light for a period of time as the temperature of said layer of photoresist material is brought to within a prescribed temperature.
Claim 10
Dependent Claim
15 words
A method according to claim 4, wherein step (c) comprises on-off modulating said electroplating current.
Claim 11
Dependent Claim
43 words
A method according to claim 1, wherein said structure includes a seed metal on which said metallization mask is selectively formed, said seed metal functioning as an electrode in said electroplating solution and promoting the deposition of the metal of said metallization pattern.
Claim 12
Dependent Claim
14 words
A method according to claim 10, wherein said support structure comprises a semiconductor device.
Claim 13
Dependent Claim
11 words
A method according to claim 11, wherein said metal is gold.
Claim 14
Dependent Claim
24 words
A method according to claim 11, wherein said semiconductor device comprises a silicon-containing layer on which a layer of said gold metal is formed.
Claim 15
Dependent Claim
23 words
A method according to claim 13, wherein said semiconductor device includes an adhesive film bonding said seed metal layer to said silicon-containing layer.
Claim 16
Dependent Claim
11 words
A method according to claim 14, wherein said metal is gold.
Claim 17
Independent Claim
115 words
A method of electrodepositing a metallization pattern on a semiconductor wafer comprising the steps of: (a) forming a layer of photoresist on said wafer and developing a prescribed metallization-defining pattern therein; (b) toughening the photoresist layer as patterned in step (a) by exposing said photoresist layer to ultraviolet radiation, so as to effectively increase the rigidity of the surface of said photoresist layer and thereby enhance its ability to resist removal during subsequent electrodeposition of metal onto said wafer; and (c) electrodepositing metallic interconnect lines on said wafer by pulsed plating metal onto the wafer, said lines being defined by the photoresist layer that has been toughened by exposure to ultraviolet radiation in step (b).
Claim 18
Independent Claim
115 words
A method of electrodepositing a metallization pattern on a semiconductor wafer comprising the steps of: (a) forming a layer of photoresist on said wafer and developing a prescribed metallization-defining pattern therein; (b) toughening the photoresist layer as patterned in step (a) by exposing said photoresist layer to ultraviolet radiation, so as to effectively increase the rigidity of the surface of said photoresist layer and thereby enhance its ability to resist removal during subsequent electrodeposition of metal onto said wafer; and (c) electrodepositing metallic interconnect lines on said wafer by pulsed plating metal onto the wafer, said lines being defined by the photoresist layer that has been toughened by exposure to ultraviolet radiation in step (b).
Claim 19
Dependent Claim
11 words
A method according to claim 16, wherein said metal is gold.
Claim 20
Dependent Claim
56 words
A method according to claim 16, wherein said pulsed plating of metal of step (c) comprises ON-OFF modulating an electrodeposition current the flow of which through an electroplating bath in which said wafer is disposed causes said metal to be deposited on said wafer in accordance with the metallization pattern defined by said layer of photoresist.
Claim 21
Dependent Claim
19 words
A metallization pattern formed on the surface of a support structure in accordance with the method of claim 1.
Claim 22
Dependent Claim
21 words
A gold interconnect pattern formed on the surface of a semiconductor wafer formed in accordance with the method of claim 18.
References Cited (Backward Citations)
US4255481A
Cited
US4514265A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-11-24 | 1990-05-26 | 1990-11-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-11-24 | 1994-05-26 | 1994-11-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-11-24 | 1998-05-26 | 1998-11-25 | $7700.00 | Window Closed / Lapsed |