US4938996A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Via filling by selective laser chemical vapor deposition
Assignee: KOZICKI MICHAEL N (425 PERCENT)
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Filing: 1988-04-12
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Granted: 1990-07-03
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Expires: 2008-04-12
Abstract
Abstract Light from a Q-switched laser passes through a metal-containing gas and through a field oxide of an integrated circuit structure. The laser light is preferentially absorbed by an underlying substrate. The substrate, but not the oxide, is heated above a threshold temperature that allows rapid chemical vapor deposition of metal through a relatively deep via hole in the oxide. The oxide has low thermal conductivity. The upper portions of the via hole walls are not heated enough to allow deposition of metal thereon. The via hole therefore can be uniformly filled by deposition of the metal on the bottom of the via hole, with no obstruction or shadowing from buildup of deposited metal on the upper wall portions of the via hole.
Inventors
- 👤 Alan R. Ziv
- 👤 Michael N. Kozicki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 12:16
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/056; H10W20/057; C; C23; C23C; C23C16/00; C23C16/04; C23C16/047; C23C16/44; C23C16/48; C23C16/481; H05; H05K; H05K3/00; H05K3/40; H05K3/4038; H05K3/4076
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
223 words
A method of forming an integrated circuit via connection, comprising the steps of: (a) providing a semiconductor substrate and an electrical connection site on the substrate, the substrate at the electrical connection site being absorptive of laser light; (b) forming an insulative layer on the substrate, the insulative layer being relatively transparent to the laser light; (c) forming a via hole in the insulative layer extending from the electrical connection site to an outer surface of the insulative layer; (d) providing a gaseous atmosphere containing atoms of a metal above the insulative layer; (e) aiming a laser beam through the atmosphere at the via hole; (f) repetitively pulsing the laser beam, the pulses having enough energy to heat material at the bottom of the via hole to a deposition threshold temperature to cause deposition of atoms of the metal onto the bottom of the via hole, the intervals between the pulses being great enough to allow enough thermal decay of the temperature at the interface between the substrate and the insulative layer by conduction of heat through the substrate that upper portions of the walls of the via hole are not heated to the deposition threshold temperature, whereby the via hole becomes filled with the metal without prior build-up of the metal on the upper portions of the walls of the via hole.
Claim 2
Independent Claim
223 words
A method of forming an integrated circuit via connection, comprising the steps of: (a) providing a semiconductor substrate and an electrical connection site on the substrate, the substrate at the electrical connection site being absorptive of laser light; (b) forming an insulative layer on the substrate, the insulative layer being relatively transparent to the laser light; (c) forming a via hole in the insulative layer extending from the electrical connection site to an outer surface of the insulative layer; (d) providing a gaseous atmosphere containing atoms of a metal above the insulative layer; (e) aiming a laser beam through the atmosphere at the via hole; (f) repetitively pulsing the laser beam, the pulses having enough energy to heat material at the bottom of the via hole to a deposition threshold temperature to cause deposition of atoms of the metal onto the bottom of the via hole, the intervals between the pulses being great enough to allow enough thermal decay of the temperature at the interface between the substrate and the insulative layer by conduction of heat through the substrate that upper portions of the walls of the via hole are not heated to the deposition threshold temperature, whereby the via hole becomes filled with the metal without prior build-up of the metal on the upper portions of the walls of the via hole.
Claim 3
Dependent Claim
64 words
The method of claim 1 wherein steps (e) and (f) include absorbing heat from the laser beam in the substrate at the bottom of the via hole and in the surface of the substrate under the insulative layer, but not absorbing enough heat from the laser beam in the insulative layer to cause build-up of the metal on the walls of the via hole.
Claim 4
Dependent Claim
40 words
The method of claim 2 wherein the first hole is approximately 0.5 to 1 microns wide and approximately 0.5 to 1 microns deep, and wherein step (e) includes causing the laser beam to be substantially wider than the first hole.
Claim 5
Dependent Claim
34 words
The method of claim 2 including forming an additional via hole through the insulative layer, wherein the laser beam is wide enough to simultaneously heat material at the bottom of the additional via hole.
Claim 6
Dependent Claim
25 words
The method of claim 4 including raster scanning the laser beam across the surface of the insulative layer and across all of the via holes.
Claim 7
Dependent Claim
55 words
The method of claim 5 wherein the raster scanning includes applying one laser pulse to a first spot of substrate, aiming the laser beam at a second spot of the substrate partially overlapping the first spot, and applying one laser pulse to the second spot at the end of a first one of the intervals.
Claim 8
Dependent Claim
31 words
The method of claim 1 including forming a layer of metal on the outer surface of the insulative layer and on the top of metal already deposited in the via hole.
Claim 9
Dependent Claim
19 words
The method of claim 1 including supporting the substrate on a chuck and controlling the temperature of the chuck.
Claim 10
Independent Claim
171 words
A method of filling a deep hole extending through a layer to a substrate, the layer being relatively transparent to laser light, the method comprising the steps of: (a) providing a gaseous atmosphere containing atoms of a thermally depositable material above the layer; (b) aiming a laser beam through the atmosphere at the hole; (c) repetitively pulsing the laser beam, the pulses having enough energy to heat the bottom of the hole to a deposition threshold temperature to cause deposition of atoms of the thermally depositable material onto the bottom of the hole, the intervals between the pulses being great enough to allow enough thermal decay of the temperature at the interface between the substrate and the layer by conduction of heat through the substrate that the upper portions of the walls of the hole are not heated to the deposition threshold temperature whereby the hole becomes filled with the thermally depositable material without prior build-up of the thermally depositable material on the upper portions of the walls of the hole.
Claim 11
Independent Claim
171 words
A method of filling a deep hole extending through a layer to a substrate, the layer being relatively transparent to laser light, the method comprising the steps of: (a) providing a gaseous atmosphere containing atoms of a thermally depositable material above the layer; (b) aiming a laser beam through the atmosphere at the hole; (c) repetitively pulsing the laser beam, the pulses having enough energy to heat the bottom of the hole to a deposition threshold temperature to cause deposition of atoms of the thermally depositable material onto the bottom of the hole, the intervals between the pulses being great enough to allow enough thermal decay of the temperature at the interface between the substrate and the layer by conduction of heat through the substrate that the upper portions of the walls of the hole are not heated to the deposition threshold temperature whereby the hole becomes filled with the thermally depositable material without prior build-up of the thermally depositable material on the upper portions of the walls of the hole.
Claim 12
Dependent Claim
43 words
The method of claim 9 wherein step (c) includes absorbing heat from the laser beam in the substrate at the bottom of the hole and in the substrate under the layer, but not absorbing substantial heat from the laser beam in the layer.
Claim 13
Dependent Claim
32 words
The method of claim 10 including forming an additional hole through the first layer, wherein the beam is wide enough to simultaneously heat material at the bottom of the additional via hole.
Claim 14
Dependent Claim
23 words
The method of claim 11 including raster scanning the laser beam across the surface of the layer and across all of the holes.
Claim 15
Dependent Claim
17 words
The method of claim 1 wherein step (e) includes making the beam wider than the via hole.
References Cited (Backward Citations)
US4701592A
Cited
US4359485A
Cited
US4511595A
Cited
US4465716A
Cited
US4544577A
Cited
US4526807A
Cited
US4624736A
Cited
US4659587A
Cited
US4699801A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-07-02 | 1994-01-01 | 1994-07-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-07-02 | 1998-01-01 | 1998-07-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-07-02 | 2002-01-01 | 2002-07-03 | $7700.00 | Window Closed / Lapsed |