US5277749A
Expired / Lapsed
US
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Methods and apparatus for relieving stress and resisting stencil delamination when performing lift-off processes that utilize high stress metals and/or multiple evaporation steps
Assignee: International Business Machines Corp
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Filing: 1991-10-17
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Granted: 1994-01-11
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Expires: 2011-10-17
Abstract
Abstract A layer of photoresist provides a stress relief (or cushion) layer between a lift-off polymer layer and a barrier of multi-level lift-off structures. When multiple evaporation steps are required using the same lift-off pattern, the adhesion between organosilicon and organic film is stressed by a first blanked metal film. To prevent delamination between the lift-off polymer layer and RIE barrier photoresist is applied on top of the lift-off polymer and sandwiched between the organosilicon and organic materials. This photoresist acts as a cushion and as an adhesion promoter to reduce delamination after the metal deposition(s).
Inventors
- 👤 Jonathan H. Griffith
- 👤 John I. Kim
- 👤 Thomas L. Leong
- 👤 William J. Tilly
- 👤 Sari Wacks
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 20:48
CPC Classifications
H; H10; H10W; H10W20/00; H10W20/01; H10W20/031; H10W20/056; H10W20/058; G; G03; G03F; G03F7/00; G03F7/004; G03F7/09; G03F7/094; H10P; H10P76/00; H10P76/20; H10P76/202; H10W20/063
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
196 words
A method of fabricating a delamination resistant multi-layer lift-off stencil on a substrate, wherein said stencil includes a lift-off structure including a lift-off polymer layer (32), a reactive ion etch (RIE) barrier (34) and a stress relief layer (33) for relieving stresses otherwise produced at the junction of said lift-off polymer layer (32) and RIE barrier (34) during single and multiple step metallization processes, comprising the steps of: (a) depositing said lift-off polymer layer (32) on said substrate; and (b) depositing said stress relief layer (33) and said RIE barrier (34) over said lift-off polymer layer (32) such that said stress relief layer (33) is interposed between said lift-off polymer layer (32) and said RIE barrier (34) to form a cushion therebetween and act as an adhesion promoter to resist stencil delamination, (c) forming in said lift-off structure a pattern exposing a portion of the surface of said substrate, (d) applying metal to said lift-off structure by evaporating at least one layer of metal onto said lift-off structure and onto said substrate through said pattern formed in said lift-off structure; and (e) removing the remainder of said lift-off structure, leaving a metal pattern on said substrate.
Claim 2
Independent Claim
196 words
A method of fabricating a delamination resistant multi-layer lift-off stencil on a substrate, wherein said stencil includes a lift-off structure including a lift-off polymer layer (32), a reactive ion etch (RIE) barrier (34) and a stress relief layer (33) for relieving stresses otherwise produced at the junction of said lift-off polymer layer (32) and RIE barrier (34) during single and multiple step metallization processes, comprising the steps of: (a) depositing said lift-off polymer layer (32) on said substrate; and (b) depositing said stress relief layer (33) and said RIE barrier (34) over said lift-off polymer layer (32) such that said stress relief layer (33) is interposed between said lift-off polymer layer (32) and said RIE barrier (34) to form a cushion therebetween and act as an adhesion promoter to resist stencil delamination, (c) forming in said lift-off structure a pattern exposing a portion of the surface of said substrate, (d) applying metal to said lift-off structure by evaporating at least one layer of metal onto said lift-off structure and onto said substrate through said pattern formed in said lift-off structure; and (e) removing the remainder of said lift-off structure, leaving a metal pattern on said substrate.
Claim 3
Dependent Claim
37 words
A method as set forth in claim 1 further comprising the steps of: (a) treating the surface of the substrate with an adhesion promoter; and (b) baking said substrate prior to depositing said lift-off polymer layer thereon.
Claim 4
Dependent Claim
22 words
A method as set forth in claim 1 wherein said lift-off layer is a polymer that may be etched by oxygen plasma.
Claim 5
Dependent Claim
21 words
A method as set forth in claim 1 wherein said lift-off layer is polymer that may be etched by RIE processing.
Claim 6
Dependent Claim
16 words
A method as set forth in claim 1 wherein said lift-off polymer layer is spin applied.
Claim 7
Dependent Claim
18 words
A method as set forth in claim 1 wherein said stress relief layer is a soft resist film.
Claim 8
Dependent Claim
16 words
A method as set forth in claim 6 wherein said stress relief layer is spin applied.
Claim 9
Dependent Claim
24 words
A method as set forth in claim 1 wherein said RIE barrier is a silicon based compound deposited by a chemical vapor deposition process.
Claim 10
Dependent Claim
17 words
A method as set forth in claim 1 wherein said RIE barrier is a plasma polymerized organosilicon.
Claim 11
Dependent Claim
21 words
A method as set forth in claim 1 further comprising the step of depositing a photoresist layer over said RIE barrier.
Claim 12
Dependent Claim
19 words
A method as set forth in claim 10 wherein said photoresist layer may be patterned utilizing a lithographic process.
Claim 13
Independent Claim
191 words
A method for applying metallized interconnections to a lift-off structure formed on a substrate, said lift-off structure including a lift-off polymer layer deposited onto said substrate, a stress relief layer deposited onto said lift-off polymer layer, a reactive ion etch (RIE) barrier deposited onto said stress relief layer and a photoresist layer deposited onto said RIE barrier, comprising the steps of: (a) patterning said photoresist layer to create a predefined image therein; (b) replicating said predefined image patterned in said photoresist layer into said lift-off polymer layer, said stress relief layer and said RIE barrier using carbon tetrafluoride to first etch said RIE barrier and then oxygen to etch said stress relief and lift-off polymer layers such that said RIE barrier overhangs the edges of said stress relief and lift-off polymer layers to facilitate metal lift-off processing, thereby forming a lift-off stencil portion of said lift-off structure (c) applying metal to said lift-off structure by evaporating at least one layer of metal onto said substrate utilizing said lift-off structure; and (d) removing said lift-off stencil portion of said lift-off structure, leaving a metallurgy pattern on said substrate, utilizing a solvent soak.
Claim 14
Independent Claim
191 words
A method for applying metallized interconnections to a lift-off structure formed on a substrate, said lift-off structure including a lift-off polymer layer deposited onto said substrate, a stress relief layer deposited onto said lift-off polymer layer, a reactive ion etch (RIE) barrier deposited onto said stress relief layer and a photoresist layer deposited onto said RIE barrier, comprising the steps of: (a) patterning said photoresist layer to create a predefined image therein; (b) replicating said predefined image patterned in said photoresist layer into said lift-off polymer layer, said stress relief layer and said RIE barrier using carbon tetrafluoride to first etch said RIE barrier and then oxygen to etch said stress relief and lift-off polymer layers such that said RIE barrier overhangs the edges of said stress relief and lift-off polymer layers to facilitate metal lift-off processing, thereby forming a lift-off stencil portion of said lift-off structure (c) applying metal to said lift-off structure by evaporating at least one layer of metal onto said substrate utilizing said lift-off structure; and (d) removing said lift-off stencil portion of said lift-off structure, leaving a metallurgy pattern on said substrate, utilizing a solvent soak.
Claim 15
Dependent Claim
26 words
A method as set forth in claim 12 further comprising the steps of heating and sputter etching said substrate prior to the step of metal evaporation.
Claim 16
Dependent Claim
37 words
A method as set forth in claim 13 further comprising the step of utilizing a metal mask to mask out unwanted areas of additional metal whenever different metal thicknesses are required in certain regions of said substrate.
Claim 17
Independent Claim
182 words
A method for applying metallized interconnections to a lift-off structure formed on a substrate, said lift-off structure including a lift-off polymer layer deposited onto said substrate, a stress relief layer deposited onto said lift-off polymer layer, a reaction ion etch (RIE) barrier deposited onto said stress relief layer and a photoresist layer deposited onto said RIE barrier, comprising the steps of: (a) patterning said photoresist layer to create a predefined image therein; and (b) replicating said predefined image patterned in said photoresist layer into said lift-off polymer layer, said stress relief layer and said RIE barrier using carbon tetrafluoride to first etch said RIE barrier and then oxygen to etch said stress relief and lift-off polymer layers such that said RIE barrier overhangs the edges of said stress relief and lift-off polymer layers to facilitate metal lift-off processing, (c) forming in said liftoff structure a pattern exposing said substrate through said pattern, (d) applying metal to said lift-off structure and through said pattern onto said substrate, and (e) removing the remainder of said lift-off structure, leaving a metal pattern on said substrate.
Claim 18
Independent Claim
182 words
A method for applying metallized interconnections to a lift-off structure formed on a substrate, said lift-off structure including a lift-off polymer layer deposited onto said substrate, a stress relief layer deposited onto said lift-off polymer layer, a reaction ion etch (RIE) barrier deposited onto said stress relief layer and a photoresist layer deposited onto said RIE barrier, comprising the steps of: (a) patterning said photoresist layer to create a predefined image therein; and (b) replicating said predefined image patterned in said photoresist layer into said lift-off polymer layer, said stress relief layer and said RIE barrier using carbon tetrafluoride to first etch said RIE barrier and then oxygen to etch said stress relief and lift-off polymer layers such that said RIE barrier overhangs the edges of said stress relief and lift-off polymer layers to facilitate metal lift-off processing, (c) forming in said liftoff structure a pattern exposing said substrate through said pattern, (d) applying metal to said lift-off structure and through said pattern onto said substrate, and (e) removing the remainder of said lift-off structure, leaving a metal pattern on said substrate.
Claim 19
Dependent Claim
27 words
A method as set forth in claim 15 wherein the step of patterning is accomplished by utilizing a lithographic process to develop said photoresist through a mask.
Claim 20
Independent Claim
118 words
A method of fabricating and using a delamination resistant multi-layer lift-off stencil, wherein said stencil includes a lift-off structure including an organic lift-off polymer layer covering a substrate and a reactive ion etch (RIE) barrier, comprising the steps of: (a) spinning a soft resist between said organic lift-off polymer layer and said RIE barrier; (b) baking said soft resist therebetween to form a stress relief layer for blanket metal deposited on said RIE barrier, (c) patterning said lift-off structure with a pattern exposing said substrate through said pattern, (d) applying metal to said lift-off structure and through said pattern onto said substrate, and (e) removing the remainder of said lift-off structure, leaving a metal pattern on said substrate.
Claim 21
Independent Claim
118 words
A method of fabricating and using a delamination resistant multi-layer lift-off stencil, wherein said stencil includes a lift-off structure including an organic lift-off polymer layer covering a substrate and a reactive ion etch (RIE) barrier, comprising the steps of: (a) spinning a soft resist between said organic lift-off polymer layer and said RIE barrier; (b) baking said soft resist therebetween to form a stress relief layer for blanket metal deposited on said RIE barrier, (c) patterning said lift-off structure with a pattern exposing said substrate through said pattern, (d) applying metal to said lift-off structure and through said pattern onto said substrate, and (e) removing the remainder of said lift-off structure, leaving a metal pattern on said substrate.
Claim 22
Independent Claim
117 words
A method of fabricating and using a delamination resistant multi-layer lift-off stencil, wherein said stencil includes a lift-off structure including an organic lift-off polymer layer covering a substrate and a reactive ion etch (RIE) barrier, comprising the steps of: (a) spraying a soft resist between said organic lift-off polymer layer and said RIE barrier; (b) baking said soft resist therebetween to form a stress relief layer for blanket metal deposited on said RIE barrier, (c) forming a pattern in said liftoff structure exposing said substrate through said pattern, (d) applying metal to said lift-off structure through said pattern onto said substrate, and (e) removing the remainder of said lift-off structure, leaving a metal pattern on said substrate.
Claim 23
Independent Claim
117 words
A method of fabricating and using a delamination resistant multi-layer lift-off stencil, wherein said stencil includes a lift-off structure including an organic lift-off polymer layer covering a substrate and a reactive ion etch (RIE) barrier, comprising the steps of: (a) spraying a soft resist between said organic lift-off polymer layer and said RIE barrier; (b) baking said soft resist therebetween to form a stress relief layer for blanket metal deposited on said RIE barrier, (c) forming a pattern in said liftoff structure exposing said substrate through said pattern, (d) applying metal to said lift-off structure through said pattern onto said substrate, and (e) removing the remainder of said lift-off structure, leaving a metal pattern on said substrate.
Claim 24
Independent Claim
130 words
A method for performing and using a metallization process utilizing high stress metals and/or multiple step evaporation, and for relieving stress and preventing multi-layer stencil delamination, wherein said stencil includes a lift-off structure including an organic lift-off polymer layer covering a substrate and a reactive ion etch (RIE) barrier, comprising the steps of: (a) utilizing said RIE barrier as a ledge for said organic lift-off polymer layer; (b) utilizing a photoresist as a stress relief layer between said lift-off polymer and RIE barrier, (c) forming a pattern in said lift-off structure with said pattern exposing said substrate through said pattern, (d) applying metal to said lift-off structure and through said pattern onto said substrate, and (e) removing the remainder of said lift-off structure, leaving a metal pattern on said substrate.
Claim 25
Independent Claim
130 words
A method for performing and using a metallization process utilizing high stress metals and/or multiple step evaporation, and for relieving stress and preventing multi-layer stencil delamination, wherein said stencil includes a lift-off structure including an organic lift-off polymer layer covering a substrate and a reactive ion etch (RIE) barrier, comprising the steps of: (a) utilizing said RIE barrier as a ledge for said organic lift-off polymer layer; (b) utilizing a photoresist as a stress relief layer between said lift-off polymer and RIE barrier, (c) forming a pattern in said lift-off structure with said pattern exposing said substrate through said pattern, (d) applying metal to said lift-off structure and through said pattern onto said substrate, and (e) removing the remainder of said lift-off structure, leaving a metal pattern on said substrate.
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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) | 1997-01-10 | 1997-07-12 | 1998-01-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-01-10 | 2001-07-12 | 2002-01-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-01-10 | 2005-07-12 | 2006-01-11 | $7700.00 | Window Closed / Lapsed |