US6315883B1
Expired / Lapsed
US
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Electroplanarization of large and small damascene features using diffusion barriers and electropolishing
Assignee: Novellus Systems Inc
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Filing: 1999-10-05
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Granted: 2001-11-13
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Expires: 2019-10-05
Abstract
Abstract A disclosed electroplanarization process involves "masking" certain regions of a wafer surface during electropolishing. The regions chosen for masking are features of relatively low aspect ratio (i.e., features that are wider than they are deep). The masking is accomplished with a material of relatively low ionic conductivity, which effectively slows or blocks transport of the metal ions produced during electropolishing. Examples of masking materials include concentrated phosphoric acid and certain polymers.
Inventors
- 👤 Steven T. Mayer
- 👤 Robert J. Contolini
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 16:42
CPC Classifications
H; H10; H10P; H10P95/00; H10P95/04; B; B23; B23H; B23H5/00; B23H5/06; B23H5/08; H10P50/00; H10P50/60; H10P50/66; H10P50/663; H10P50/667; H10P52/00; H10P52/40; H10P52/403
Claims Analysis
Total Claims: 34
Claim 1
Independent Claim
145 words
A method of forming conductive features via a damascene process, the method comprising: providing a partially fabricated integrated circuit having a dielectric layer with trenches where said conductive features are to be formed; forming a substantially conformal layer of conductive material over the dielectric layer, whereby the conductive material has a surface comprising recesses over the trenches and substantially flat field regions around the trenches; selectively applying a diffusion barrier film to the recesses; electropolishing the conductive material surface, whereby the conductive material is removed from the recesses more slowly than from the field regions to thereby increase the planarity of the conductive material surface; and removing the conductive material at a substantially uniform rate over the surface of the conductive material until reaching the dielectric layer, whereby said conductive features remain in said trenches, insulated from one another by regions of the dielectric layer.
Claim 2
Independent Claim
145 words
A method of forming conductive features via a damascene process, the method comprising: providing a partially fabricated integrated circuit having a dielectric layer with trenches where said conductive features are to be formed; forming a substantially conformal layer of conductive material over the dielectric layer, whereby the conductive material has a surface comprising recesses over the trenches and substantially flat field regions around the trenches; selectively applying a diffusion barrier film to the recesses; electropolishing the conductive material surface, whereby the conductive material is removed from the recesses more slowly than from the field regions to thereby increase the planarity of the conductive material surface; and removing the conductive material at a substantially uniform rate over the surface of the conductive material until reaching the dielectric layer, whereby said conductive features remain in said trenches, insulated from one another by regions of the dielectric layer.
Claim 3
Dependent Claim
20 words
The method of claim 1 , wherein the conductive features include at least one of interconnect lines and contact pads.
Claim 4
Dependent Claim
31 words
The method of claim 1 , wherein the dielectric layer is formed of a material selected from the group consisting of silicon oxides, aluminum nitride, paraffin, and organic and inorganic aerogels.
Claim 5
Dependent Claim
18 words
The method of claim 1 , wherein the trenches have an aspect ratio of at most about 1:1.
Claim 6
Dependent Claim
18 words
The method of claim 1 , wherein the trenches have an aspect ratio of at most about 1:3.
Claim 7
Dependent Claim
21 words
The method of claim 1 , wherein forming the substantially conformal layer comprises electroplating the conductive material onto the dielectric layer.
Claim 8
Dependent Claim
27 words
The method of claim 1 , wherein forming the substantially conformal layer comprises using a process selected from the group comprising chemical vapor deposition, sputtering, and evaporation.
Claim 9
Dependent Claim
13 words
The method of claim 1 , wherein the conductive material is a metal.
Claim 10
Dependent Claim
17 words
The method of claim 1 , wherein the conductive material is copper or an alloy of copper.
Claim 11
Dependent Claim
19 words
The method of claim 1 , wherein the diffusion barrier film is a liquid film or a polymer film.
Claim 12
Dependent Claim
31 words
The method of claim 10 , wherein the diffusion barrier film is a liquid film including at least about 25% phosphoric acid by weight and a salt of the conductive material.
Claim 13
Dependent Claim
33 words
The method of claim 1 , wherein the diffusion barrier film comprises a polymeric film selected from the group consisting of a nylon, polyvinylidene difluoride, polyacrylonitrile, polymethylacrylonitrile, ethylene propylene diene monomer, and polyvinylchloride.
Claim 14
Dependent Claim
28 words
The method of claim 1 , wherein removing the conductive material at a substantially uniform rate comprises chemical mechanical polishing, wet etching, a second electropolishing procedure, or electroetching.
Claim 15
Independent Claim
55 words
A method of electroplanarizing a substrate surface having recesses surrounded by substantially flat field regions, the method comprising: selectively applying a diffusion barrier film to the recesses; and electropolishing the substrate surface, whereby material is removed from the recesses more slowly than from the field regions to thereby increase the planarity of the substrate surface.
Claim 16
Independent Claim
55 words
A method of electroplanarizing a substrate surface having recesses surrounded by substantially flat field regions, the method comprising: selectively applying a diffusion barrier film to the recesses; and electropolishing the substrate surface, whereby material is removed from the recesses more slowly than from the field regions to thereby increase the planarity of the substrate surface.
Claim 17
Dependent Claim
15 words
The method of claim 14 , wherein the substrate is a partially fabricated integrated circuit.
Claim 18
Dependent Claim
26 words
The method of claim 14 , wherein the substrate surface is a surface of a metal layer that conformally coats a dielectric layer with damascene features.
Claim 19
Dependent Claim
18 words
The method of claim 14 , wherein the recesses have an aspect ratio of at most about 1:1.
Claim 20
Dependent Claim
23 words
The method of claim 14 , wherein the diffusion barrier film is applied in a manner providing it with a substantially planar surface.
Claim 21
Dependent Claim
26 words
The method of claim 18 , wherein the diffusion barrier film is applied by a process selected from the group consisting of dipping, spraying, and metering.
Claim 22
Dependent Claim
31 words
The method of claim 19 , wherein the diffusion barrier film is planarized by spraying the surface of the film with a solvent for the film while the substrate is spinning.
Claim 23
Dependent Claim
45 words
The method of claim 14 , wherein the diffusion barrier film has a diffusion coefficient for ions of the material to be removed that is lower than an electropolishing bath electrolyte diffusion coefficient for said ions, wherein the bath electrolyte is used during the electropolishing.
Claim 24
Dependent Claim
37 words
The method of claim 14 , wherein the diffusion barrier film has a diffusion coefficient for ions of the material to be removed that varies inversely with the concentration of said ions in the diffusion barrier film.
Claim 25
Dependent Claim
23 words
The method of claim 14 , wherein the diffusion barrier film is a viscous liquid that is soluble in an electropolishing bath electrolyte.
Claim 26
Dependent Claim
24 words
The method of claim 23 , wherein the diffusion barrier film is phosphoric acid having a concentration of at least about 25% by weight.
Claim 27
Dependent Claim
25 words
The method of claim 24 , wherein the diffusion barrier film contains phosphoric acid in a concentration of between about 40 and 85% by weight.
Claim 28
Dependent Claim
22 words
The method of claim 24 , wherein the diffusion barrier film includes one or more of water, propylene carbonate, and ethylene carbonate.
Claim 29
Dependent Claim
21 words
The method of claim 23 , wherein the diffusion barrier film further comprises a salt of the material to be removed.
Claim 30
Dependent Claim
37 words
The method of claim 23 , wherein the diffusion barrier film further comprises a surface agent selected from the group consisting of wetting agents, brightening agents, and compounds that increase the kinetic overpotential of an electropolishing cathode.
Claim 31
Dependent Claim
22 words
The method of claim 14 , wherein the diffusion barrier film is insoluble in an electropolishing bath electrolyte used during the electropolishing.
Claim 32
Dependent Claim
22 words
The method of claim 14 , wherein the diffusion barrier film is non-conductive to ions generated from the substrate during the electropolishing.
Claim 33
Dependent Claim
33 words
The method of claim 14 , wherein the diffusion barrier film comprises a polymeric film selected from the group consisting of a nylon, polyvinylidene difluoride, polyacrylonitrile, polymethylacrylonitrile, ethylene propylene diene monomer, and polyvinylchloride.
Claim 34
Dependent Claim
27 words
The method of claim 14 , wherein electropolishing is performed in an electropolishing bath electrolyte having a lower viscosity and higher conductivity than the diffusion barrier film.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-11-12 | 2005-05-14 | 2005-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-11-12 | 2009-05-14 | 2009-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-11-12 | 2013-05-14 | 2013-11-13 | $7700.00 | Window Closed / Lapsed |