|Publication number||US20020025762 A1|
|Application number||US 09/775,865|
|Publication date||Feb 28, 2002|
|Filing date||Feb 2, 2001|
|Priority date||Feb 16, 2000|
|Also published as||WO2001060940A1|
|Publication number||09775865, 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|
|Inventors||Qiuliang Luo, Wendy Goldberg, Qianqiu Ye|
|Original Assignee||Qiuliang Luo, Goldberg Wendy B., Ye Qianqiu (Christine)|
|Export Citation||BiBTeX, EndNote, RefMan|
|Referenced by (9), Classifications (7), Legal Events (1)|
|External Links: USPTO, USPTO Assignment, Espacenet|
 This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/182,960 filed Feb. 16, 2000.
 This invention relates to the protection of polishing slurries and silica dispersions from the proliferation of bacteria and/or fungi by means of biocides.
 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).
 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.
 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.
 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.
 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.
 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
 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
 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.
 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
 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.
 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.
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|US6750257 *||Jan 15, 2001||Jun 15, 2004||Fuso Chemical, Ltd.||Colloidal silica slurry|
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|US7300480||Sep 25, 2003||Nov 27, 2007||Rohm And Haas Electronic Materials Cmp Holdings, Inc.||High-rate barrier polishing composition|
|US7491252||Mar 25, 2003||Feb 17, 2009||Rohm And Haas Electronic Materials Cmp Holdings, Inc.||Tantalum barrier removal solution|
|US7501346 *||Jul 21, 2006||Mar 10, 2009||Cabot Microelectronics Corporation||Gallium and chromium ions for oxide rate enhancement|
|US8506661 *||Oct 24, 2008||Aug 13, 2013||Air Products & Chemicals, Inc.||Polishing slurry for copper films|
|US20050070211 *||Sep 25, 2003||Mar 31, 2005||Jinru Bian||Barrier polishing fluid|
|EP1357161A2 *||Apr 17, 2003||Oct 29, 2003||JSR Corporation||Aqueous dispersion for chemical mechanical polishing|
|International Classification||C09G1/02, C09K3/14|
|Cooperative Classification||C09K3/1463, C09G1/02|
|European Classification||C09G1/02, C09K3/14D2|
|May 11, 2001||AS||Assignment|
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