US5773364A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for using ammonium salt slurries for chemical mechanical polishing (CMP)
Assignee: NXP USA Inc
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Filing: 1996-10-21
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Granted: 1998-06-30
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Expires: 2016-10-21
Abstract
Abstract A method for chemical/mechanical polishing (CMP) uses a slurry (22). This slurry (22) contains one or more ammonium salts, such as ammonium nitride (NH 4 NO 3 ), as an oxidizing/etching species within the slurry (22). This slurry (22) is used to polish a metal layer (14) whereby the ammonium salt does not create slurry distribution problems, does not contain metallic species, does not contain mobile ions like potassium, and is environmentally safe.
Inventors
- 👤 Janos Farkas
- 👤 Melissa Freeman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 23:58
CPC Classifications
H; H10; H10P; H10P52/00; H10P52/40; H10P52/403
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
101 words
A method for polishing a semiconductor wafer, the method comprising the steps of: providing a polishing surface; exposing the polishing surface to a slurry, the slurry containing an mono-basic ammonium salt with exception of ammonium sulfate and ammonium halides; moving the polishing surface; bringing the semiconductor wafer having a conductive layer into contact with the slurry while thepolishing surface is moving; and polishing the conductive layer having a top surface wherein the conductive layer is located on an exposed surface of the semiconductor wafer, the mono-basic ammonium salt within the slurry facilitating removal of a top portion of the conductive layer.
Claim 2
Independent Claim
101 words
A method for polishing a semiconductor wafer, the method comprising the steps of: providing a polishing surface; exposing the polishing surface to a slurry, the slurry containing an mono-basic ammonium salt with exception of ammonium sulfate and ammonium halides; moving the polishing surface; bringing the semiconductor wafer having a conductive layer into contact with the slurry while thepolishing surface is moving; and polishing the conductive layer having a top surface wherein the conductive layer is located on an exposed surface of the semiconductor wafer, the mono-basic ammonium salt within the slurry facilitating removal of a top portion of the conductive layer.
Claim 3
Dependent Claim
26 words
The method of claim 1 wherein an abrasive species is added to the slurry to facilitate mechanical removal of the exposed surface of the conductive layer.
Claim 4
Dependent Claim
32 words
The method of claim 1 wherein the conductive layer has a recessed area, wherein an additive is added to the slurry to inhibit corrosion of the recessed area of the conductive layer.
Claim 5
Dependent Claim
44 words
The method of claim 1 wherein the step of polishing further comprises: forming a passivation layer on a portion of the top surface of the conductive layer, the passivation layer being formed by an interaction between the mono-basic ammonium salt and the conductive layer.
Claim 6
Dependent Claim
37 words
The method of claim 4 wherein the step of polishing further comprises: mechanically removing the passivation layer to reduce a total thickness of the conductive layer and render the top surface of the conductive layer substantially planar.
Claim 7
Dependent Claim
38 words
The method of claim 4 wherein the step of polishing further comprises: chemically removing the passivation layer from to reduce a total thickness of the conductive layer and render the top surface of the conductive layer substantially planar.
Claim 8
Dependent Claim
16 words
The method of claim 1 wherein the mono-basic ammonium salt is NH 4 NO 3 .
Claim 9
Dependent Claim
16 words
The method of claim 1 wherein the mono-basic ammonium salt is NH 4 NI 4 .
Claim 10
Dependent Claim
16 words
The method of claim 1 wherein the mono-basic ammonium salt is NH 4 NI 3 .
Claim 11
Dependent Claim
16 words
The method of claim 1 wherein the mono-basic ammonium salt is NH 4 PO 3 .
Claim 12
Dependent Claim
12 words
The method of claim 1 wherein the conductive layer substantially comprises copper.
Claim 13
Dependent Claim
13 words
The method of claim 1 wherein the conductive layer substantially comprises refractory metal.
Claim 14
Dependent Claim
12 words
The method of claim 1 wherein the conductive layer substantially comprises aluminum.
Claim 15
Dependent Claim
14 words
The method of claim 1 wherein the conductive layer substantially comprises a conductive nitride.
Claim 16
Dependent Claim
55 words
The method of claim 1 wherein the mono-basic ammonium salt is selected from a group consisting of: NH 4 Al(SO 4 ) 2 , NH 4 Ce(NO 3 ) 6 , NH 4 Ce(SO 4 ) 4 , NH 4 Fe(C 2 O 4 ) 3 , and NH 4 Fe(SO 4 ) 2 .
Claim 17
Independent Claim
117 words
A method for polishing a semiconductor wafer, the method comprising the steps of: providing a polishing surface; exposing the polishing surface to a slurry, the slurry containing an ammonium salt with exception of ammonium sulfate and ammonium halides which is either mono-basic or di-basic; moving the polishing surface; bringing the semiconductor wafer into contact with the slurry while the polishing surface is moving; and polishing a conductive layer having a top surface wherein the conductive layer is located on an exposed surface of the semiconductor wafer, the ammonium salt within the slurry facilitating removal of a top portion of the conductive layer wherein the conductive layer contains atoms selected from a group consisting of: aluminum and copper.
Claim 18
Independent Claim
117 words
A method for polishing a semiconductor wafer, the method comprising the steps of: providing a polishing surface; exposing the polishing surface to a slurry, the slurry containing an ammonium salt with exception of ammonium sulfate and ammonium halides which is either mono-basic or di-basic; moving the polishing surface; bringing the semiconductor wafer into contact with the slurry while the polishing surface is moving; and polishing a conductive layer having a top surface wherein the conductive layer is located on an exposed surface of the semiconductor wafer, the ammonium salt within the slurry facilitating removal of a top portion of the conductive layer wherein the conductive layer contains atoms selected from a group consisting of: aluminum and copper.
Claim 19
Dependent Claim
14 words
The method of claim 16 wherein the ammonium salt is a dibasic ammonium salt.
Claim 20
Dependent Claim
14 words
The method of claim 16 wherein the ammonium salt is a mono-basic ammonium salt.
Claim 21
Dependent Claim
15 words
The method of claim 16 wherein the ammonium salt is NH 4 NO 3 .
Claim 22
Dependent Claim
15 words
The method of claim 16 wherein the ammonium salt is NH 4 IO 4 .
Claim 23
Dependent Claim
15 words
The method of claim 16 wherein the ammonium salt is NH 4 IO 3 .
Claim 24
Dependent Claim
15 words
The method of claim 16 wherein the ammonium salt is NH 4 PO 3 .
Claim 25
Dependent Claim
21 words
The method of claim 16 wherein the ammonium salt is (NH 4 ) 2 HC 6 H 5 O 7 .
Claim 26
Dependent Claim
19 words
The method of claim 16 wherein the ammonium salt is (NH 4 ) 2 C 2 O 4 .
Claim 27
Dependent Claim
17 words
The method of claim 16 wherein the ammonium salt is (NH 4 ) 2 CO 3 .
Claim 28
Dependent Claim
17 words
The method of claim 16 wherein the ammonium salt is (NH 4 ) 2 SO 4 .
Claim 29
Dependent Claim
21 words
The method of claim 16 wherein the ammonium salt is (NH 4 ) 2 C 4 H 4 O 6 .
Claim 30
Dependent Claim
54 words
The method of claim 16 wherein the ammonium salt is selected from a group consisting of: NH 4 Al(SO 4 ) 2 , NH 4 Ce(NO 3 ) 6 , NH 4 Ce(SO 4 ) 4 , NH 4 Fe(C 2 O 4 ) 3 , and NH 4 Fe(SO 4 ) 2 .
Claim 31
Independent Claim
139 words
A method for polishing a silicon wafer having a top metallic layer, the method comprising the steps of: providing a polishing pad having a polishing surface; exposing the polishing surface to a slurry, the slurry containing an oxidizer/etcher which is NH 4 NO 3 ; rotating the polishing pad; bringing the silicon wafer into contact with the slurry while the polishing surface is rotating; rotating the silicon wafer when in contact with the slurry; forming, via interaction between the top metallic layer and the NH 4 NO 3 , a passivation layer on a portion of the top metallic layer while the silicon wafer is in contact with the slurry; and removing the passivation layer from the top metallic layer via the slurry whereby, over time, the top metallic layer is polished to have a substantially planar top surface.
Claim 32
Independent Claim
139 words
A method for polishing a silicon wafer having a top metallic layer, the method comprising the steps of: providing a polishing pad having a polishing surface; exposing the polishing surface to a slurry, the slurry containing an oxidizer/etcher which is NH 4 NO 3 ; rotating the polishing pad; bringing the silicon wafer into contact with the slurry while the polishing surface is rotating; rotating the silicon wafer when in contact with the slurry; forming, via interaction between the top metallic layer and the NH 4 NO 3 , a passivation layer on a portion of the top metallic layer while the silicon wafer is in contact with the slurry; and removing the passivation layer from the top metallic layer via the slurry whereby, over time, the top metallic layer is polished to have a substantially planar top surface.
References Cited (Backward Citations)
US5527423A
Cited
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2001-06-29 | 2001-12-29 | 2002-06-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-06-29 | 2005-12-29 | 2006-06-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-06-29 | 2009-12-29 | 2010-06-30 | $7700.00 | Window Closed / Lapsed |