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Publication numberUS20020025762 A1
Publication typeApplication
Application numberUS 09/775,865
Publication dateFeb 28, 2002
Filing dateFeb 2, 2001
Priority dateFeb 16, 2000
Also published asWO2001060940A1
Publication number09775865, 775865, US 2002/0025762 A1, US 2002/025762 A1, US 20020025762 A1, US 20020025762A1, US 2002025762 A1, US 2002025762A1, US-A1-20020025762, US-A1-2002025762, US2002/0025762A1, US2002/025762A1, US20020025762 A1, US20020025762A1, US2002025762 A1, US2002025762A1
InventorsQiuliang Luo, Wendy Goldberg, Qianqiu Ye
Original AssigneeQiuliang Luo, Goldberg Wendy B., Ye Qianqiu (Christine)
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Biocides for polishing slurries
US 20020025762 A1
Abstract
Compounds containing both a sulfur and a nitrogen in a five-membered ring structure are used as biocides in polishing solutions and slurries.
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Claims(12)
What is claimed is:
1. An aqueous solution, for use in CMP of semiconductor wafers wherein a fixed abrasive polishing pad is used, which contains essentially no abrasive particles and which is protected from bacterial and fungal activity by means of a biocide comprising an organic compound with a five membered ring containing both a sulfur and a nitrogen group in said ring.
2. An aqueous slurry, for use in CMP of semiconductor wafers, which contains abrasive particles and which is protected from bacterial and fungal activity by means of a biocide comprising an organic compound with a five membered ring containing both a sulfur and a nitrogen group in said ring.
3. The solution of claim 1 wherein said biocide is from the group comprising 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazolin-3-one.
4. The slurry of claim 2 wherein said biocide is from the group comprising 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazolin-3-one.
5. The solution of claim 1 wherein said biocide is present in the range of 0.01% to 1% by weight of said solution.
6. The slurry of claim 2 wherein said biocide is present in the range of 0.01% to 1% by weight of said slurry.
7. A method of polishing a semiconductor wafer comprising: applying a solution at a polishing interface between a fixed abrasive polishing pad and said wafer, said solution comprising essentially no abrasive particles and which is protected from bacterial and fungal activity by means of a biocide comprising an organic compound with a five membered ring containing both a sulfur and a nitrogen group in said ring.
8. A method of polishing a semiconductor wafer comprising: applying a slurry at a polishing interface between a polishing pad and said wafer, said solution comprising abrasive particles and which is protected from bacterial and fungal activity by means of a biocide comprising an organic compound with a five membered ring containing both a sulfur and a nitrogen group in said ring.
9. A method according to claim 5 wherein said biocide is from the group comprising 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazolin-3-one.
10. A method according to claim 6 wherein said biocide is from the group comprising 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazolin-3-one.
11. A method according to claim 5 wherein said biocide is present in the range of 0.01% to 1% by weight of said solution.
12. A method according to claim 6 wherein said biocide is present in the range of 0.01% to 1% by weight of said slurry.
Description
CROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/182,960 filed Feb. 16, 2000.

FIELD OF THE INVENTION

[0002] This invention relates to the protection of polishing slurries and silica dispersions from the proliferation of bacteria and/or fungi by means of biocides.

DESCRIPTION OF RELATED ART

[0003] The problem of bacterial and fungal growth in silica polishing slurries is addressed in U.S. Pat. No. 5,230,833 (Romberger et al.). It includes a thorough summary of the early related art. Bactericides disclosed in '833 are tetramethylammonium chloride, tetraethylammonium chloride, tetrapropylammonium chloride, alkylbenzyldimethylammonium chloride, and alkylbenzyldimethylammonium hydroxide, wherein the alkyl chaim ranges from 1 to about 20 carbon atoms. Also, the preferred biocide is sodium chlorite or sodium hypochlorite. The preferred fungicide is sodium OMADINE® (pyrithone).

[0004] U.S. Pat. No. 3,377,275 discloses a synergistic blend of 3,5-di-methyl tetrahydro 1,3,5,2H-thiadiazine-2-thione in combination with formaldehyde as a microbiocide for aqueous colloidal silica sols.

[0005] It has been found in recent years that the above chemicals are not always compatible with abrasive slurries used for chemical-mechanical polishing (CMP) of semiconductor wafers and with abrasive free slurries used with fixed abrasive polishing pads for semiconductor wafer polishing. It is the object of this invention to provide biocides which are not detrimental to the polishing of semiconductor wafers. Embodiments of the invention will now be described by way of example, with reference to the following detailed description.

SUMMARY OF THE INVENTION

[0006] It has been found that a five membered organic ring compound containing both a sulfur and a nitrogen in the ring provide biocide protection of CMP slurries without affecting polishing performance. Examples of such compounds are 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one.

DETAILED DESCRIPTION

[0007] A class of biocides has been found which do not significantly affect the polishing performance of both particle-free solutions for use with fixed abrasive pads and slurries comprising metal oxide abrasives such as alumina, ceria, zirconia, and silica. These biocides comprise a five-membered organic ring compound containing both a sulfur and a nitrogen in the ring.

EXAMPLE 1

[0008] A chemical polishing solution for use with a fixed abrasive pad was made up with the following components: ammonium hydrogen phosphate, iminodiacetic acid, 5-methyl-1H-benzotriazole, surfactant, and hydrogen peroxide. Removal rates were determined using a Strasbaugh 6DS-SP Planarizer and a 3M fixed abrasive matrix MRW64 pad. The process was fixed at 4 psi downforce, 60 rpm platen speed, and 40 rpm carrier speed. Biocide 1 (Kathon CGICP II available from Rohn and Haas Company, Philadelphia, Pa.) and Biocide 2 (Neolone M50 available from Rohm and Haas Company, Philadelphia, Pa.) were added at a concentration of 0.15% by weight to solution batches. The active ingredients in these biocides are 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazolin-3-one. Results of polishing patterned wafers are shown in Table 1.

TABLE 1
Polishing Results
10 um 25 um 100 um 90% BP 0.5 0.5
Sample lines lines lines 4.5/.5 120 um Bpe 2.5/2.5 1.5/1.5
Control #1 461 652 1126 908 515 23 159 167
Biocide #1 503 751  922 692 472 40 212 221
Biocide #2 510 658 1085 855 570 93 301 242
Control #2 652 830 1052 1003  649 47 348 279

[0009] These results show little or no effect from adding the biocide to the particle-free solutions. Similar solutions were prepared and evaluated using a challenge test with the intentional additions of bacteria and fungi.

TABLE 2
Challenge Test Results
Sample Days Testing Results*
Control 14 4F
Biocide #1 14 0
Biocide #2 14 0

EXAMPLE 2

[0010] A polishing slurry comprising as major components iodic acid, lactic acid, potassium hydrogen phthalate, and metal oxide abrasive (a mixture of alumina and titania) was made up as slurry A. To a portion of this slurry was added 0.10% by weight of Kathon® CGICP biocide (active ingredients 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazolin-3-one). This slurry was designated slurry B.

[0011] Wafers comprising tungsten (W), titanium (Ti), and silicon dioxide (Ox) were polished on a standard CMP polishing machine using slurry A and slurry B. Results of the polishing are shown in Table 3.

TABLE 3
Avg. W RR Avg. Ti RR Avg. Ox RR
Slurry Angstroms/min Angstroms/min Angstroms/min
A 3392 545 65
B 3533 564 64
B 3565 889 105
A 3291 891 62

EXAMPLE 3

[0012] A CMP slurry was made up with the following major components: Klebosol 1498-50 (silica sol), citric acid (complexing agent), benzotriazol (corrosion inhibitor), and a surfactant. Addition of a small amount (about 0.1%) of Neolone® (available from Rohm and Haas Company) gave adequate biocide protection to the CMP slurry while the slurry provided slightly improved surface quality when the slurry was used as a second step slurry for polishing semiconductor wafers comprising copper.

[0013] It is obvious from the above results that the addition of a biocide comprised of 2-methyl-4-isothiazolin-3-one and/or 5-chloro-2-methyl-4-isothiazolin-3-one in an amount sufficient to provide antibacterial and antifungal protection to the slurry does not adversely affect the polishing performance of a slurry. It performs particularly well on slurries which comprise Klebosol® silica sol as an ingredient. A sufficient amount of biocide is in the range of 0.01% to 1% by weight of the CMP solution or slurry.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US6750257 *Jan 15, 2001Jun 15, 2004Fuso Chemical, Ltd.Colloidal silica slurry
US6786944Apr 14, 2003Sep 7, 2004Jsr CorporationAqueous dispersion for chemical mechanical polishing
US7241725Sep 25, 2003Jul 10, 2007Rohm And Haas Electronic Materials Cmp Holdings, Inc.Barrier polishing fluid
US7300480Sep 25, 2003Nov 27, 2007Rohm And Haas Electronic Materials Cmp Holdings, Inc.High-rate barrier polishing composition
US7491252Mar 25, 2003Feb 17, 2009Rohm And Haas Electronic Materials Cmp Holdings, Inc.Tantalum barrier removal solution
US7501346 *Jul 21, 2006Mar 10, 2009Cabot Microelectronics CorporationGallium and chromium ions for oxide rate enhancement
US8506661 *Oct 24, 2008Aug 13, 2013Air Products & Chemicals, Inc.Polishing slurry for copper films
US20050070211 *Sep 25, 2003Mar 31, 2005Jinru BianBarrier polishing fluid
EP1357161A2 *Apr 17, 2003Oct 29, 2003JSR CorporationAqueous dispersion for chemical mechanical polishing
Classifications
U.S. Classification451/41
International ClassificationC09G1/02, C09K3/14
Cooperative ClassificationC09K3/1463, C09G1/02
European ClassificationC09G1/02, C09K3/14D2
Legal Events
DateCodeEventDescription
May 11, 2001ASAssignment
Owner name: RONDEL HOLDINGS, INC., DELAWARE
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:LUO, QIULIANG;GOLDBERG, WENDY B.;YE, QIANQIU (CHRISTINE);REEL/FRAME:011792/0948;SIGNING DATES FROM 20010329 TO 20010508