US5916855A
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US
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Chemical-mechanical polishing slurry formulation and method for tungsten and titanium thin films
Assignee: GlobalFoundries Inc
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Filing: 1997-03-26
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Granted: 1999-06-29
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Expires: 2017-03-26
Abstract
Abstract A polishing slurry composition and its method of making for planarization of silicon semiconductor wafers by chemical mechanical polishing of the wafer. A slurry formulation utilizing a ferric salt tungsten oxidizer, an ammonium persulfate titanium oxidizer, a fatty acid suspension agent, alumina particles with a small diameter and tight diameter range, coated with a solubility coating, and a chemical stabilizer, provides high tungsten and titanium polish rates with high selectivity to silicon dioxide, and good oxide defectivity for use in tungsten local interconnect applications. A method for making a tungsten slurry includes first thoroughly blending small diameter alumina particles with a tight diameter range in an aqueous concentrate with a suspension agent, then mixing with water and oxidizers. Ferric salt tungsten slurries made by this method provide excellent tungsten polish characteristics for via plug and local interconnect applications.
Inventors
- 👤 Steven C. Avanzino
- 👤 Christy Mei-Chu Woo
- 👤 Diana Marie Schonauer
- 👤 Peter Austin Burke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 21:18
CPC Classifications
C; C09; C09G; C09G1/00; C09G1/02; C09K; C09K3/00; C09K3/14; C09K3/1454; C09K3/1463; H; H10; H10P; H10P52/00; H10P52/40; H10P52/403
Claims Analysis
Total Claims: 56
Claim 1
Independent Claim
61 words
A chemical-mechanical polishing (CMP) slurry comprising: abrasive particles, all said abrasive particles having a median particle diameter less than 0.400 microns and a one sigma deviation about said median diameter of 0.05 microns or less, said particles having a solubility coating thereon, said solubility coating being a phthalate-containing compound; a ferric salt oxidizer; a suspension agent; and a titanium oxidizing agent.
Claim 2
Dependent Claim
61 words
A chemical-mechanical polishing (CMP) slurry comprising: abrasive particles, all said abrasive particles having a median particle diameter less than 0.400 microns and a one sigma deviation about said median diameter of 0.05 microns or less, said particles having a solubility coating thereon, said solubility coating being a phthalate-containing compound; a ferric salt oxidizer; a suspension agent; and a titanium oxidizing agent.
Claim 3
Dependent Claim
9 words
The slurry of claim 1, further comprising DI water.
Claim 4
Dependent Claim
20 words
The slurry of claim 2, wherein said solubility coating comprises in the range of 0.8-1.1 wt % of said slurry.
Claim 5
Dependent Claim
33 words
The slurry of claim 3, comprising 2-6 wt % alumina abrasive particles, 10-30 volume % suspension agent, and wherein said solubility coating comprises in the range of 0.8-1.1 wt % of said slurry.
Claim 6
Dependent Claim
16 words
The slurry of claim 4, wherein said solubility coating comprises 0.9 wt % of said slurry.
Claim 7
Dependent Claim
33 words
The slurry of claim 2, wherein said titanium oxidizing agent is selected from the group consisting of: ammonium persulfate, potassium persulfate, sodium persulfate, citric acid, ceric ammonium nitrate, potassium iodate, and hydrogen peroxide.
Claim 8
Dependent Claim
13 words
The slurry of claim 6, wherein said titanium oxidizing agent is ammonium persulfate.
Claim 9
Dependent Claim
34 words
The slurry of claim 7, comprising 2-6 wt % alumina abrasive particles, 10-30 volume % suspension agent, and wherein said titanium oxidizing agent comprises in the range of 0.1-9.0 wt % of said slurry.
Claim 10
Dependent Claim
17 words
The slurry of claim 8, wherein said titanium oxidizing agent comprises 2 wt % of said slurry.
Claim 11
Dependent Claim
44 words
The slurry of claim 2, wherein said aqueous suspension agent is selected from the group consisting of: stearic acid, palmitic acid, myristic acid, lauric acid, coconut oil, palm oil, peanut oil, ethylene glycol, propylene glycol, glycerol, polyethylene glycol aliphatic polyethers, alkyl sulfates, alkoxylated alkyphenols.
Claim 12
Dependent Claim
18 words
The slurry of claim 10, wherein said suspension agent is an aqueous mixture containing fat and/or fatty acid.
Claim 13
Dependent Claim
19 words
The slurry of claim 11 wherein said suspension agent comprises a mixture of stearic acid and a vegetable oil.
Claim 14
Dependent Claim
37 words
The slurry of claim 12, wherein said suspension agent is EVERFLO, comprising mostly water, about 12 1/2 wt % stearic acid, about 12 1/2 wt % vegetable oil, and small amounts of methyl paraben and propylene glycol.
Claim 15
Dependent Claim
27 words
The slurry of claim 13, comprising 2-6 wt % alumina abrasive particles, wherein said suspension agent comprises in the range of 10-30 volume % of said slurry.
Claim 16
Dependent Claim
16 words
The slurry of claim 14, wherein said suspension agent comprises 15 volume % of said slurry.
Claim 17
Dependent Claim
10 words
The slurry of claim 2, further comprising a chemical stabilizer.
Claim 18
Dependent Claim
26 words
The slurry of claim 16, wherein said chemical stabilizer comprises a soluble chloride salt having a cation inert with respect to the chemicals in the slurry.
Claim 19
Dependent Claim
26 words
The slurry of claim 17, wherein said chemical stabilizer is selected from the group consisting of ammonium chloride, potassium chloride, sodium chloride, and FeCl 3 .
Claim 20
Dependent Claim
12 words
The slurry of claim 18, wherein said chemical stabilizer is ammonium chloride.
Claim 21
Dependent Claim
33 words
The slurry of claim 19, comprising 2-6 wt % alumina abrasive particles, 10-30 volume % suspension agent, and wherein said chemical stabilizer comprises in the range of 0.7-3.0 wt % of said slurry.
Claim 22
Dependent Claim
16 words
The slurry of claim 20, wherein said chemical stabilizer comprises 2 wt % of said slurry.
Claim 23
Dependent Claim
33 words
The slurry of claim 2, wherein said abrasive particles are selected from the group consisting of Al 2 O 3 , SiC, SiO 2 , CeO 2 and Si 3 N 4 .
Claim 24
Dependent Claim
15 words
The slurry of claim 22, wherein said abrasive particles are Al 2 O 3 .
Claim 25
Dependent Claim
27 words
The slurry of claim 23, comprising 10-30 volume % suspension agent, and wherein said abrasive particles comprise in the range of 2-6 wt % of said slurry.
Claim 26
Dependent Claim
16 words
The slurry of claim 24, wherein said abrasive particles comprise 2.8 wt % of said slurry.
Claim 27
Dependent Claim
23 words
The slurry of claim 23, wherein the median diameter of the abrasive particles is in the range between 0.170 microns and 0.270 microns.
Claim 28
Dependent Claim
48 words
The slurry of claim 2, wherein said ferric salt oxidizer is selected from the group consisting of Fe(NO 3 ) 3 .9H 2 O, Fe 2 (SO 4 ) 3 .5H 2 O, FeCl 3 .6H 2 O, and FeNH 4 (SO 4 ) 2 .12H 2 O.
Claim 29
Dependent Claim
18 words
The slurry of claim 27, wherein said ferric salt oxidizer is Fe(NO 3 ) 3 .9H 2 O.
Claim 30
Dependent Claim
30 words
The slurry of claim 28, comprising 2-6 wt % alumina abrasive particles, 10-30 volume % suspension agent, and wherein said ferric salt oxidizer comprises 2 wt % of said slurry.
Claim 31
Dependent Claim
17 words
The slurry of claim 29, wherein said ferric salt oxidizer comprises 2 wt % of said slurry.
Claim 32
Independent Claim
69 words
A method for making a chemical-mechanical polishing (CMP) slurry comprising the steps of: providing abrasive particles in an aqueous concentrate having a median particle diameter less than 0.400 microns; blending said abrasive particles in said aqueous concentrate with a suspension agent; then mixing water and at least two different oxidizers including a ferric salt oxidizer and a titanium oxidizing agent with said blended abrasive particles to form a slurry.
Claim 33
Independent Claim
69 words
A method for making a chemical-mechanical polishing (CMP) slurry comprising the steps of: providing abrasive particles in an aqueous concentrate having a median particle diameter less than 0.400 microns; blending said abrasive particles in said aqueous concentrate with a suspension agent; then mixing water and at least two different oxidizers including a ferric salt oxidizer and a titanium oxidizing agent with said blended abrasive particles to form a slurry.
Claim 34
Dependent Claim
22 words
The method of claim 31 wherein said step of providing said abrasive particles includes said abrasive particles having a solubility coating thereon.
Claim 35
Dependent Claim
15 words
The method of claim 32 wherein said abrasive particles are Al 2 O 3 .
Claim 36
Dependent Claim
13 words
The method of claim 33 wherein said solubility coating is ammonium hydrogen phthalate.
Claim 37
Dependent Claim
37 words
The method of claim 34 wherein said suspension agent is EVERFLO, comprising mostly water, about 12 1/2 wt % stearic acid, about 12 1/2 wt % vegetable oil, and small amounts of methyl paraben and propylene glycol.
Claim 38
Dependent Claim
13 words
The method of claim 35 wherein said titanium oxidizing agent is ammonium persulfate.
Claim 39
Dependent Claim
18 words
The method of claim 36 wherein said ferric salt oxidizer is Fe(NO 3 ) 3 .9H 2 O.
Claim 40
Dependent Claim
17 words
The method of claim 37 further including the step of mixing a chemical stabilizer with said slurry.
Claim 41
Dependent Claim
12 words
The method of claim 38 wherein said chemical stabilizer is ammonium chloride.
Claim 42
Dependent Claim
23 words
The method of claim 39 wherein the median diameter of the abrasive particles is in the range between 0.170 microns and 0.270 microns.
Claim 43
Dependent Claim
41 words
The method of claim 40 wherein said step of blending said abrasive particles includes physically vigorously mixing said particles in said aqueous concentrate with said suspension agent for a time on the order of two hours before addition of said water.
Claim 44
Dependent Claim
57 words
The method of claim 41 wherein said abrasive particle concentrate is 20 volume %, said ammonium hydrogen phthalate is 0.9 wt %, said suspension agent is 15 volume %, said water is 65 volume %, said ferric nitrate is 2 wt %, said ammonium persulfate is 2 wt %, and said ammonium chloride is 2 wt %.
Claim 45
Dependent Claim
13 words
A Chemical Mechanical Polishing (CMP) slurry made by the method of claim 31.
Claim 46
Dependent Claim
13 words
A Chemical Mechanical Polishing (CMP) slurry made by the method of claim 35.
Claim 47
Dependent Claim
13 words
A Chemical Mechanical Polishing (CMP) slurry made by the method of claim 38.
Claim 48
Dependent Claim
13 words
A Chemical Mechanical Polishing (CMP) slurry made by the method of claim 39.
Claim 49
Dependent Claim
13 words
A Chemical Mechanical Polishing (CMP) slurry made by the method of claim 42.
Claim 50
Dependent Claim
20 words
The Chemical-Mechanical Polishing (CMP) slurry of claim 1, wherein said solubility coating comprises a phthalate-containing compound including ammonium hydrogen phthalate.
Claim 51
Dependent Claim
19 words
The Chemical-Mechanical Polishing (CMP) slurry of claim 1, wherein said solubility coating comprises a phthalate-containing compound including phthalic acid.
Claim 52
Dependent Claim
19 words
The Chemical-Mechanical Polishing (CMP) slurry of claim 1, wherein said solubility coating comprises a phthalate-containing compound including diammonium phthalate.
Claim 53
Dependent Claim
19 words
The Chemical-Mechanical Polishing (CMP) slurry of claim 1, wherein said solubility coating comprises a phthalate-containing compound including potassium phthalate.
Claim 54
Dependent Claim
19 words
The Chemical-Mechanical Polishing (CMP) slurry of claim 1, wherein said solubility coating comprises a phthalate-containing compound including sodium phthalate.
Claim 55
Dependent Claim
98 words
A chemical-mechanical polishing (CMP) slurry comprising: a ferric salt oxidizer; a suspension agent; a titanium oxidizing agent; and abrasive particles, all said abrasive particles having a median particle diameter less than 0.400 microns and a one sigma deviation about said median diameter of 0.05 microns or less, said particles having a solubility coating thereon, said solubility coating being selected from the group consisting of: ammonium hydrogen phthalate, phthalic acid, diammonium phthalate, mono- or di- potassium or sodium phthalate, sodium acetylacetonate monohydrate, potassium acetylacetonate hemihydrate, succinic acid, ammonium succinate, sodium succinate, potassium succinate, 2,3-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid.
Claim 56
Dependent Claim
98 words
A chemical-mechanical polishing (CMP) slurry comprising: a ferric salt oxidizer; a suspension agent; a titanium oxidizing agent; and abrasive particles, all said abrasive particles having a median particle diameter less than 0.400 microns and a one sigma deviation about said median diameter of 0.05 microns or less, said particles having a solubility coating thereon, said solubility coating being selected from the group consisting of: ammonium hydrogen phthalate, phthalic acid, diammonium phthalate, mono- or di- potassium or sodium phthalate, sodium acetylacetonate monohydrate, potassium acetylacetonate hemihydrate, succinic acid, ammonium succinate, sodium succinate, potassium succinate, 2,3-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid.
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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) | 2002-06-28 | 2002-12-28 | 2003-06-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-06-28 | 2006-12-28 | 2007-06-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-06-28 | 2010-12-28 | 2011-06-29 | $7700.00 | Window Closed / Lapsed |