US6333255B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for making semiconductor device containing low carbon film for interconnect structures
Assignee: RPX Corp
•
Filing: 1998-08-20
•
Granted: 2001-12-25
•
Expires: 2018-08-20
Abstract
Abstract A lower carbon film as a provisional film, a lower SiO 2 film and an upper carbon film are formed, and then trenches having a wiring pattern are formed in the upper carbon film. Next, contact holes are formed through the lower carbon film and the lower SiO 2 film. Then, wires and plugs are formed by filling in the trenches and contact holes with a barrier metal film and a Cu alloy film. After these process steps are repeatedly performed several times, a dummy opening is formed to extend downward through the uppermost SiO 2 film. Thereafter, the carbon films are removed by performing ashing with oxygen introduced through the dummy opening. As a result, gas layers are formed to surround the wires and plugs. In this manner, a highly reliable gas-dielectric interconnect structure can be obtained by performing simple process steps.
Inventors
- 👤 Mitsuru Sekiguchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 11:37
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/063; H10W20/071; H10W20/072; H10W20/40; H10W20/45; H10W20/46; H10W20/48; H10W20/495; H10W20/41; H10W20/425
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
134 words
A method for fabricating a semiconductor device, said method comprising the steps of: a) forming a plurality of interconnect layers by sequentially stacking plugs and wires on a substrate, and forming an insulating film and a provisional film for each said interconnect layer; wherein for each interconnect layer, the insulating film of a given interconnect layer laterally interconnects the wires of the given interconnect layer to each other, the provisional film filling in regions surrounding the plugs and the wires; b) forming an opening to pass through at least the uppermost one of the insulating films and the uppermost one of the provisional films that are formed in step a); and c) removing all the provisional films while leaving the insulating films, thereby turning the regions where the provisional films existed into gas layers.
Claim 2
Independent Claim
134 words
A method for fabricating a semiconductor device, said method comprising the steps of: a) forming a plurality of interconnect layers by sequentially stacking plugs and wires on a substrate, and forming an insulating film and a provisional film for each said interconnect layer; wherein for each interconnect layer, the insulating film of a given interconnect layer laterally interconnects the wires of the given interconnect layer to each other, the provisional film filling in regions surrounding the plugs and the wires; b) forming an opening to pass through at least the uppermost one of the insulating films and the uppermost one of the provisional films that are formed in step a); and c) removing all the provisional films while leaving the insulating films, thereby turning the regions where the provisional films existed into gas layers.
Claim 3
Dependent Claim
110 words
The method of claim 1 , wherein the step a) is performed by repeating several times the sub-steps of: i) forming a first provisional film on the substrate; ii) forming through holes in the first provisional film; iii) forming the plugs out of a conductive material to fill in the through holes; iv) forming a second provisional film over the substrate after the sub-step iii) has been performed; v) forming trenches having a wiring pattern in the second provisional film; vi) forming the wires out of a conductive material to fill in the trenches; and vii) forming an insulating film over the substrate after the sub-step vi) has been performed.
Claim 4
Dependent Claim
39 words
The method of claim 2 , wherein step a) further comprises the sub-step of forming an intermediate insulating film in the middle of the provisional film, said intermediate insulating film functioning as an etch stopper for forming the trenches.
Claim 5
Dependent Claim
113 words
The method of claim 1 , wherein the step a) is performed by repeating several times the sub-steps of: i) forming a provisional film over a semiconductor substrate; ii) forming trenches and through holes in the provisional film, each said through hole extending downward from the bottom of an associated one of the trenches and passing through the provisional film; iii) forming the wires out of a conductive material to fill in the trenches and the plugs out of the conductive material to fill in the through holes; and iv) forming an insulating film over the substrate so as to come into contact with the wires after the sub-step iii) has been performed.
Claim 6
Dependent Claim
39 words
The method of claim 4 , wherein step a) further comprises the sub-step of forming an intermediate insulating film in the middle of the provisional film, said intermediate insulating film functioning as an etch stopper for forming the trenches.
Claim 7
Dependent Claim
91 words
The method of claim 1 , wherein the step a) is performed by repeating several times the sub-steps of: i) forming a provisional film over a semiconductor substrate; ii) forming through holes in the provisional film; iii) forming the plugs out of a conductive material to fill in the through holes, and the wires to be connected to the plugs and to extend upward through the provisional film; and iv) forming an insulating film over the substrate between the sub-steps i) and ii) and/or after the sub-step iii) has been performed.
Claim 8
Dependent Claim
35 words
The method of claim 1 , wherein in the step a), a carbon film is formed as the provisional film, and wherein in the step c), the carbon film is removed by ashing with oxygen.
Claim 9
Dependent Claim
44 words
The method of claim 1 , wherein in the step a), the provisional film is made of a material having a high etch selectivity with respect to the insulating film, and wherein in the step c), the provisional film is removed by isotropic etching.
Claim 10
Dependent Claim
46 words
The method of claim 1 , further comprising the step of forming a coating insulating film on exposed surfaces of the wires and the plugs by introducing an insulating material into the gas layers through at least the opening after the step c) has been performed.
Claim 11
Dependent Claim
57 words
The method of claim 1 , further comprising the step of forming a low-dielectric-constant film by introducing an insulating material into the gas layers through at least the opening and thereby filling in the gas layers with a material having a lower dielectric constant than that of the insulating film, after the step c) has been performed.
Claim 12
Dependent Claim
75 words
The method of claim 10 , further comprising the step of connecting bonding wires to the wires in the uppermost one of the interconnect layers after the step c) has been performed and before the step of forming the low-dielectric-constant film is performed, wherein in the step of forming the low-dielectric-constant film, the low-dielectric-constant film is formed so as to cover connection portions between the wires in the uppermost interconnect layer and the bonding wires.
Claim 13
Dependent Claim
18 words
The method of claim 1 , wherein no portion of the insulating films are removed during step c).
References Cited (Backward Citations)
JPS61107747A
Cited
JPS61107746A
Cited
US4933743A
Cited
US5117276A
Cited
US5468685A
Cited
JPH0685070A
Cited
US5530290A
Cited
US5324683A
Cited
JPH0817918A
Cited
JPH08250592A
Cited
US5567982A
Cited
US5559055A
Cited
US5900668A
Cited
JPH09172068A
Cited
US5994776A
Cited
US5798559A
Cited
US5923074A
Cited
JPH10199978A
Cited
US5950102A
Cited
JPH10294316A
Cited
US6064118A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-12-24 | 2005-06-25 | 2005-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-12-24 | 2009-06-25 | 2009-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-12-24 | 2013-06-25 | 2013-12-25 | $7700.00 | Window Closed / Lapsed |