US5571373A
Expired / Lapsed
US
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Method of rough polishing semiconductor wafers to reduce surface roughness
Assignee: SunEdison Semiconductor Ltd
•
Filing: 1994-05-18
•
Granted: 1996-11-05
•
Expires: 2014-05-18
Abstract
Abstract A method of rough polishing a semiconductor wafer to reduce roughness on a surface of the wafer prior to finish polishing the wafer by applying a polishing solution to a polishing material, contacting the polishing material and the polishing solution with the surface of the wafer as the wafer moves relative to the polishing material to reduce low frequency surface roughness of the wafer, applying a second polishing solution to the polishing material, and contacting the polishing material and the second polishing solution with the surface of the wafer as the wafer moves relative to the polishing material to further reduce the low frequency surface roughness, wherein the wafer has an average surface roughness not greater than 1.0 nm Ra, as measured on a 1 mmx1 mm scan with an optical interferometer, after being rough polished.
Inventors
- 👤 Vepa Krishna
- 👤 Michael S. Wisnieski
- 👤 Lois Illig
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:29
CPC Classifications
H; H10; H10P; H10P52/00; H10P52/40; H10P52/402
Claims Analysis
Total Claims: 41
Claim 1
Independent Claim
153 words
A method of rough polishing a semiconductor wafer to reduce roughness on a surface of the wafer prior to finish polishing the wafer, the method comprising the steps of: (a) applying a first polishing solution to a polishing material; (b) contacting the polishing material and the first polishing solution with the surface of the wafer as the wafer moves relative to the polishing material to reduce low frequency surface roughness of the wafer; (c) applying a second polishing solution containing an ammonia stabilized colloidal silica slurry to the polishing material; and (d) contacting the polishing material and the second polishing solution with the surface of the wafer as the wafer moves relative to the polishing material to further reduce the low frequency surface roughness, wherein the wafer has an average surface roughness not greater than 1.0 nmRa, as measured on a 1 mm×1 mm scan with an optical interferometer, after being rough polished.
Claim 2
Independent Claim
153 words
A method of rough polishing a semiconductor wafer to reduce roughness on a surface of the wafer prior to finish polishing the wafer, the method comprising the steps of: (a) applying a first polishing solution to a polishing material; (b) contacting the polishing material and the first polishing solution with the surface of the wafer as the wafer moves relative to the polishing material to reduce low frequency surface roughness of the wafer; (c) applying a second polishing solution containing an ammonia stabilized colloidal silica slurry to the polishing material; and (d) contacting the polishing material and the second polishing solution with the surface of the wafer as the wafer moves relative to the polishing material to further reduce the low frequency surface roughness, wherein the wafer has an average surface roughness not greater than 1.0 nmRa, as measured on a 1 mm×1 mm scan with an optical interferometer, after being rough polished.
Claim 3
Dependent Claim
37 words
The method of claim 1 wherein the low frequency surface roughness is reduced to no greater than 2.0 nm Ra in step (b) and is further reduced to no greater than 1.0 nm Ra in step (d).
Claim 4
Dependent Claim
17 words
The method of claim 1 wherein the first polishing solution includes a sodium stabilized colloidal silica slurry.
Claim 5
Dependent Claim
19 words
The method of claim 1 wherein the first polishing solution or the second polishing solution includes an alkaline etchant.
Claim 6
Dependent Claim
15 words
The method of claim 1 wherein the polishing material is a hard polyurethane impregnated pad.
Claim 7
Dependent Claim
34 words
The method of claim 1 further including the step of applying an acidic solution to the wafer and rinsing the wafer with water to quench the second polishing solution after rough polishing the wafer.
Claim 8
Dependent Claim
29 words
The method of claim 1 wherein the wafer is not treated with an acidic solution or rinsed with water before the second solution is applied to the polishing material.
Claim 9
Dependent Claim
23 words
The method of claim 3 wherein the alkaline etchant is an amine reinforced caustic solution having a pH of about 11 to 14.
Claim 10
Dependent Claim
17 words
The method of claim 8 wherein the amine reinforced caustic solution contains potassium hydroxide and ethylene diamine.
Claim 11
Dependent Claim
23 words
The method of claim 4 wherein the alkaline etchant is an amine reinforced caustic solution having a pH of about 11 to 14.
Claim 12
Dependent Claim
14 words
The method of claim 10 wherein the solution contains potassium hydroxide and ethylene diamine.
Claim 13
Dependent Claim
19 words
The method of claim 6 wherein the acidic solution contains an organic or inorganic acid and a polyether polyol.
Claim 14
Dependent Claim
13 words
The method of claim 1 wherein the semiconductor wafer is a silicon wafer.
Claim 15
Dependent Claim
43 words
The method of claim 1 wherein the low frequency surface roughness is reduced to about 1.2 nm Ra to about 2.0 nm Ra in step (b) and is further reduced to about 0.5 nm Ra to about 0.8 nm Ra in step (d).
Claim 16
Dependent Claim
37 words
The method of claim 13 wherein from about 16 μm to about 18 μm of silicon are removed during step (b) and from about 2 μm to about 4 μm of silicon are removed during step (d).
Claim 17
Independent Claim
151 words
A method of rough polishing a semiconductor wafer to reduce roughness on a surface of the wafer prior to finish polishing the wafer, the method comprising the steps of: (a) applying a first solution to a hard polishing pad; (b) contacting the polishing pad and the first solution with the surface of the wafer as the wafer moves relative to the polishing pad to reduce low frequency surface roughness of the wafer to no greater than 2.0 nm Ra; (c) then applying a second solution containing an ammonia stabilized silica slurry to the polishing pad; and (d) then contacting the polishing pad and the second solution with the surface of the wafer as the wafer moves relative to the polishing pad to further reduce the low frequency surface roughness to no greater than 1.0 nm Ra, the surface roughness being measured on a 1 mm×1 mm scan with an optical interferometer.
Claim 18
Independent Claim
151 words
A method of rough polishing a semiconductor wafer to reduce roughness on a surface of the wafer prior to finish polishing the wafer, the method comprising the steps of: (a) applying a first solution to a hard polishing pad; (b) contacting the polishing pad and the first solution with the surface of the wafer as the wafer moves relative to the polishing pad to reduce low frequency surface roughness of the wafer to no greater than 2.0 nm Ra; (c) then applying a second solution containing an ammonia stabilized silica slurry to the polishing pad; and (d) then contacting the polishing pad and the second solution with the surface of the wafer as the wafer moves relative to the polishing pad to further reduce the low frequency surface roughness to no greater than 1.0 nm Ra, the surface roughness being measured on a 1 mm×1 mm scan with an optical interferometer.
Claim 19
Dependent Claim
16 words
The method of claim 16 wherein the first solution includes a sodium stabilized colloidal silica slurry.
Claim 20
Dependent Claim
15 words
The method of claim 16 wherein the hard polishing pad is a polyurethane impregnated pad.
Claim 21
Dependent Claim
33 words
The method of claim 16 further including the step of applying an acidic solution to the wafer and rinsing the wafer with water to quench the second solution after rough polishing the wafer.
Claim 22
Dependent Claim
29 words
The method of claim 16 wherein the wafer is not treated with an acidic solution or rinsed with water before the second solution is applied to the polishing material.
Claim 23
Dependent Claim
18 words
The method of claim 17 wherein the first solution or the second solution further includes an alkaline etchant.
Claim 24
Dependent Claim
23 words
The method of claim 21 wherein the alkaline etchant is an amine reinforced caustic solution having a pH of about 11 to 14.
Claim 25
Dependent Claim
16 words
The method of claim 22 wherein the alkaline etchant contains potassium hydroxide, ethylene diamine and water.
Claim 26
Dependent Claim
21 words
The method of claim 19 wherein the acidic solution contains a polyether polyol, isopropanol, hydrogen peroxide and acetic or sulfuric acid.
Claim 27
Dependent Claim
13 words
The method of claim 16 wherein the semiconductor wafer is a silicon wafer.
Claim 28
Dependent Claim
43 words
The method of claim 16 wherein the low frequency surface roughness is reduced to about 1.2 nm Ra to about 2.0 nm Ra in step (b) and is further reduced to about 0.5 nm Ra to about 0.8 nm Ra in step (d).
Claim 29
Dependent Claim
37 words
The method of claim 25 wherein from about 16 μm to about 18 μm of silicon are removed during step (b) and from about 2 μm to about 4 μm of silicon are removed during step (d).
Claim 30
Independent Claim
162 words
A method of rough polishing a semiconductor wafer to reduce roughness on a surface of the wafer prior to finish polishing the wafer, the method comprising the steps of: (a) applying a first polishing solution to a polishing material; (b) contacting the polishing material and the first polishing solution with the surface of the wafer as the wafer moves relative to the polishing material to reduce low frequency surface roughness of the wafer; (c) applying a second polishing solution to the polishing material, the second polishing solution containing an ammonia stabilized colloidal silica slurry and an alkaline etchant; and (d) contacting the polishing material and the second polishing solution with the surface of the wafer as the wafer moves relative to the polishing material to further reduce the low frequency surface roughness, wherein the wafer has an average surface roughness not greater than 1.0 nm Ra, as measured on a 1 mm×1 mm scan with an optical interferometer, after being rough polished.
Claim 31
Independent Claim
162 words
A method of rough polishing a semiconductor wafer to reduce roughness on a surface of the wafer prior to finish polishing the wafer, the method comprising the steps of: (a) applying a first polishing solution to a polishing material; (b) contacting the polishing material and the first polishing solution with the surface of the wafer as the wafer moves relative to the polishing material to reduce low frequency surface roughness of the wafer; (c) applying a second polishing solution to the polishing material, the second polishing solution containing an ammonia stabilized colloidal silica slurry and an alkaline etchant; and (d) contacting the polishing material and the second polishing solution with the surface of the wafer as the wafer moves relative to the polishing material to further reduce the low frequency surface roughness, wherein the wafer has an average surface roughness not greater than 1.0 nm Ra, as measured on a 1 mm×1 mm scan with an optical interferometer, after being rough polished.
Claim 32
Independent Claim
97 words
A method of polishing a semiconductor wafer to reduce roughness on a surface of the wafer, the method comprising the steps of: (a) applying a first polishing solution to a polishing pad; (b) contacting the polishing pad and the first solution with the surface of the wafer as the wafer moves relative to the polishing pad; (c) applying a second polishing solution containing an ammonia stabilized silica slurry to the polishing pad; and (d) contacting the polishing pad and the second solution with the surface of the wafer as the wafer moves relative to the polishing pad.
Claim 33
Independent Claim
97 words
A method of polishing a semiconductor wafer to reduce roughness on a surface of the wafer, the method comprising the steps of: (a) applying a first polishing solution to a polishing pad; (b) contacting the polishing pad and the first solution with the surface of the wafer as the wafer moves relative to the polishing pad; (c) applying a second polishing solution containing an ammonia stabilized silica slurry to the polishing pad; and (d) contacting the polishing pad and the second solution with the surface of the wafer as the wafer moves relative to the polishing pad.
Claim 34
Dependent Claim
17 words
The method of claim 29 wherein the first polishing solution includes a sodium stabilized colloidal silica slurry.
Claim 35
Dependent Claim
19 words
The method of claim 30 wherein the first polishing solution or the second polishing solution includes an alkaline etchant.
Claim 36
Dependent Claim
33 words
The method of claim 29 further including the step of applying an acidic solution to the wafer and rinsing the wafer with water to quench the second polishing solution after polishing the wafer.
Claim 37
Dependent Claim
29 words
The method of claim 29 wherein the wafer is not treated with an acidic solution or rinsed with water before the second solution is applied to the polishing material.
Claim 38
Dependent Claim
23 words
The method of claim 31 wherein the alkaline etchant is an amine reinforced caustic solution having a pH of about 11 to 14.
Claim 39
Dependent Claim
17 words
The method of claim 34 wherein the amine reinforced caustic solution contains potassium hydroxide and ethylene diamine.
Claim 40
Dependent Claim
19 words
The method of claim 33 wherein the acidic solution contains an organic or inorganic acid and a polyether polyol.
Claim 41
Dependent Claim
13 words
The method of claim 29 wherein the semiconductor wafer is a silicon wafer.
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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) | 1999-11-05 | 2000-05-06 | 2000-11-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-11-05 | 2004-05-06 | 2004-11-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-11-05 | 2008-05-06 | 2008-11-05 | $7700.00 | Window Closed / Lapsed |