US5750415A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low dielectric constant layers via immiscible sol-gel processing
Assignee: Texas Instruments Inc
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Filing: 1994-05-27
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Granted: 1998-05-12
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Expires: 2014-05-27
Abstract
Abstract A method for forming air gaps 22 between metal leads 16 of a semiconductor device. A metal layer is deposited on a substrate 12. The metal layer is etched to form metal leads 16, exposing portions of the substrate 12. A disposable liquid 18 is deposited on the metal leads 16 and the exposed portions of substrate 12, and a top portion of the disposable liquid 18 is removed to lower the disposable liquid 18 to at least the tops of the leads 16. A porous silica precursor film 20 is deposited on the disposable liquid 18 and over the tops of the leads 16. The porous silica precursor film 20 is gelled to form a low-porosity silica film 24. The disposable liquid 18 is removed through the low-porosity silica film 24 to form air gaps 22 between metal leads 16 beneath the low-porosity silica film 24. The air gaps 22 have a low dielectric constant and result in reduced capacitance between the metal leads and decreased power consumption.
Inventors
- 👤 Bruce E. Gnade
- 👤 Chih-Chen Cho
- 👤 Douglas M. Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 01:01
CPC Classifications
H; H10; H10P; H10P14/00; H10P14/60; H10P14/69; H10P14/692; H10P14/6921; H10P14/6922; H10P14/63; H10P14/6326; H10P14/6342; H10P14/65; H10P14/6502; H10P14/6506; H10P14/6516; H10P14/6548; H10P14/66; H10P14/665; H10W; H10W20/00; H10W20/01; H10W20/071; H10W20/072; H10W20/40; H10W20/45; H10W20/46; H10W20/48; H10W20/495; H10W20/074; H10W20/077
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
149 words
A method for forming air gaps between metal leads of a semiconductor device, comprising the steps of: depositing a metal layer on a substrate; etching said metal layer in a pattern to form metal leads, said metal leads having tops, wherein portions of said substrate remain exposed; depositing a disposable liquid on said metal leads and said exposed portions of substrate; removing a top portion of said disposable liquid to lower said disposable liquid to a level at least as low as said tops of said metal leads; depositing a porous silica precursor film on said disposable liquid and at least said tops of said leads, said porous silica precursor film comprising a first solvent; gelling said porous silica precursor film to form a low-porosity silica film; removing said disposable liquid through said low-porosity silica film to form air gaps between said metal leads beneath said low-porosity silica film.
Claim 2
Independent Claim
149 words
A method for forming air gaps between metal leads of a semiconductor device, comprising the steps of: depositing a metal layer on a substrate; etching said metal layer in a pattern to form metal leads, said metal leads having tops, wherein portions of said substrate remain exposed; depositing a disposable liquid on said metal leads and said exposed portions of substrate; removing a top portion of said disposable liquid to lower said disposable liquid to a level at least as low as said tops of said metal leads; depositing a porous silica precursor film on said disposable liquid and at least said tops of said leads, said porous silica precursor film comprising a first solvent; gelling said porous silica precursor film to form a low-porosity silica film; removing said disposable liquid through said low-porosity silica film to form air gaps between said metal leads beneath said low-porosity silica film.
Claim 3
Dependent Claim
22 words
The method of claim 1 wherein said disposable liquid reaches said tops of said leads, after said depositing a disposable liquid step.
Claim 4
Dependent Claim
35 words
The method of claim 1 further comprising the step of forming a passivating layer on at least said metal leads, after said step of etching said metal layer in a pattern to form metal leads.
Claim 5
Dependent Claim
12 words
The method of claim 3 wherein said passivating layer comprises a nitride.
Claim 6
Dependent Claim
26 words
The method of claim 1 wherein said removing said disposable liquid through said low-porosity silica film step comprises heating said wafer to vaporize said disposable liquid.
Claim 7
Dependent Claim
29 words
The method of claim 1 wherein said removing said disposable liquid through said low-porosity silica film step comprises applying a vacuum to said wafer to remove said disposable liquid.
Claim 8
Dependent Claim
15 words
The method of claim 1 wherein said porous silica precursor film further comprises a sol-gel.
Claim 9
Dependent Claim
13 words
The method of claim 1 wherein said disposable liquid comprises said first solvent.
Claim 10
Dependent Claim
13 words
The method of claim 1 wherein said disposable liquid comprises a second solvent.
Claim 11
Dependent Claim
14 words
The method of claim 1 or claim 8 wherein said first solvent comprises decane.
Claim 12
Dependent Claim
22 words
The method of claim 1 further comprising the step of depositing a structural dielectric layer, after said removing said disposable liquid step.
Claim 13
Independent Claim
139 words
A method for forming air gaps between metal leads of a semiconductor device, comprising the steps of: depositing a metal layer on a substrate; etching said metal layer in a pattern to form metal leads, said metal leads having tops, wherein portions of said substrate are exposed; depositing a disposable liquid on said substrate layer and said metal leads; removing a top portion of said disposable liquid to lower said disposable liquid to a level at least as low as the tops of said metal leads; depositing a sol-gel on said disposable liquid and at least said tops of said metal leads, said sol-gel comprising a first solvent; gelling said sol-gel to form a low-porosity silica film; removing said disposable liquid through said low-porosity silica film to form air gaps between said metal leads beneath said low-porosity silica film.
Claim 14
Independent Claim
139 words
A method for forming air gaps between metal leads of a semiconductor device, comprising the steps of: depositing a metal layer on a substrate; etching said metal layer in a pattern to form metal leads, said metal leads having tops, wherein portions of said substrate are exposed; depositing a disposable liquid on said substrate layer and said metal leads; removing a top portion of said disposable liquid to lower said disposable liquid to a level at least as low as the tops of said metal leads; depositing a sol-gel on said disposable liquid and at least said tops of said metal leads, said sol-gel comprising a first solvent; gelling said sol-gel to form a low-porosity silica film; removing said disposable liquid through said low-porosity silica film to form air gaps between said metal leads beneath said low-porosity silica film.
Claim 15
Dependent Claim
35 words
The method of claim 12 further comprising the step of forming a passivating layer on at least said metal leads, after said step of etching said metal layer in a pattern to form metal leads.
Claim 16
Dependent Claim
12 words
The method of claim 13 wherein said passivating layer comprises a nitride.
Claim 17
Dependent Claim
22 words
The method of claim 12 further comprising the step of depositing a structural dielectric layer, after said removing said disposable liquid step.
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