Patents by Inventor Karunasena A. Alahapperuma
Karunasena A. Alahapperuma has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 8038750Abstract: A structured abrasive article comprises a backing with a topographically structured abrasive layer secured thereto. The topographically structured abrasive layer comprises precisely-shaped abrasive composites. A solid overlayer comprising eroding particles with a Mohs scale hardness of at least 4 and a water-soluble polymer is disposed on at least a portion of the topographically structured abrasive layer. Methods of making and using the structured abrasive articles are also disclosed.Type: GrantFiled: July 13, 2007Date of Patent: October 18, 2011Assignee: 3M Innovative Properties CompanyInventors: Joseph G Pribyl, Karunasena Alahapperuma, Craig F. Lamphere, Edward J. Woo
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Publication number: 20090017727Abstract: A structured abrasive article comprises a backing with a topographically structured abrasive layer secured thereto. The topographically structured abrasive layer comprises precisely-shaped abrasive composites. A solid overlayer comprising eroding particles with a Mohs scale hardness of at least 4 and a water-soluble polymer is disposed on at least a portion of the topographically structured abrasive layer. Methods of making and using the structured abrasive articles are also disclosed.Type: ApplicationFiled: July 13, 2007Publication date: January 15, 2009Inventors: Joseph G. Pribyl, Karunasena Alahapperuma, Craig F. Lamphere, Edward J. Woo
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Patent number: 6759121Abstract: A radiation detackifiable adhesive composition comprising a (meth)acrylate copolymer including from 85 wt. % to 97.5 wt. % of a (meth)acrylate ester and from 2.5 wt. % to 15 wt. % of a copolymerizable carboxylate monomer and a multi-functional urethane acrylate oligomer combined with the (meth)acrylate copolymer to provide from 25 parts to 40 parts of the oligomer per 100 parts of the copolymer. The adhesive composition becomes progressively detackified during exposure to ultraviolet radiation. Properties of adhesive compositions may be maintained at elevated temperatures, from about 115° C. to about 155° C., when they include a thermally stable free radical initiator to overcome premature adhesive detackification. The present invention further provides a clear adhesive coated sheet for supporting a silicon wafer during manufacture of semiconductor microchips. The coated sheet comprises a transparent film substrate coated with a radiation detackifiable adhesive composition.Type: GrantFiled: December 11, 2001Date of Patent: July 6, 2004Assignee: 3M Innovative Properties CompanyInventors: Karunasena A. Alahapperuma, Peter A. Stark
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Publication number: 20030108738Abstract: A radiation detackifiable adhesive composition comprising a (meth)acrylate copolymer including from 85 wt. % to 97.5 wt. % of a (meth)acrylate ester and from 2.5 wt. % to 15 wt. % of a copolymerizable carboxylate monomer and a multi-functional urethane acrylate oligomer combined with the (meth)acrylate copolymer to provide from 25 parts to 40 parts of the oligomer per 100 parts of the copolymer. The adhesive composition becomes progressively detackified during exposure to ultraviolet radiation. Properties of adhesive compositions may be maintained at elevated temperatures, from about 115° C. to about 155° C., when they include a thermally stable free radical initiator to overcome premature adhesive detackification.Type: ApplicationFiled: December 11, 2001Publication date: June 12, 2003Applicant: 3M Innovative Properties CompanyInventors: Karunasena A. Alahapperuma, Peter A. Stark
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Patent number: 6478918Abstract: A semiconductor wafer processing tape includes a permanent backing and a layer of a nonpressure sensitive adhesive. The tapes are useful for wafer grinding and/or wafer dicing applications. The nonpressure sensitive adhesive includes a copolymer of at least one of a first monoethylenically unsaturated monomer, at least one of a second monoethylenically unsaturated monomer, and at least one copolymerizable nonionic crosslinking agent; wherein the second monoethylenically unsaturated monomer is a reinforcing monomer having a homopolymer glass transition temperature higher than that of the first monoethylenically unsaturated monomer. A method of processing semiconductor wafers is also provided.Type: GrantFiled: January 18, 2001Date of Patent: November 12, 2002Assignee: 3M Innovative Properties CompanyInventors: Richard E. Bennett, Louis E. Winslow, Greggory S. Bennett, Karunasena A. Alahapperuma, Cheryl L. Moore
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Patent number: 6472065Abstract: A radiation detackifiable adhesive composition comprising a (meth)acrylate copolymer including from about 85 wt. % to about 97.5 wt. % of a (meth)acrylate ester and from about 2.5 wt. % to about 15 wt. % of a copolymerizable carboxylate monomer and a multi-functional urethane acrylate oligomer combined with the (meth)acrylate copolymer to provide from about 25 parts to about 40 parts of the oligomer per 100 parts of the copolymer. The adhesive composition becomes progressively detackified during exposure to ultraviolet radiation. The present invention further provides a clear adhesive coated sheet for supporting a silicon wafer during manufacture of semiconductor microchips. The coated sheet comprises a transparent film substrate coated with a radiation detackifiable adhesive composition.Type: GrantFiled: July 13, 2000Date of Patent: October 29, 2002Assignee: 3M Innovative Properties CompanyInventors: Karunasena A. Alahapperuma, Steven S. Kantner
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Publication number: 20010016257Abstract: A semiconductor wafer processing tape includes a permanent backing and a layer of a nonpressure sensitive adhesive. The tapes are useful for wafer grinding and/or wafer dicing applications. The nonpressure sensitive adhesive includes a copolymer of at least one of a first monoethylenically unsaturated monomer, at least one of a second monoethylenically unsaturated monomer, and at least one copolymerizable nonionic crosslinking agent; wherein the second monoethylenically unsaturated monomer is a reinforcing monomer having a homopolymer glass transition temperature higher than that of the first monoethylenically unsaturated monomer. A method of processing semiconductor wafers is also provided.Type: ApplicationFiled: January 18, 2001Publication date: August 23, 2001Applicant: 3M Innovative Properties CompanyInventors: Richard E. Bennett, Louis E. Winslow, Greggory S. Bennett, Karunasena A. Alahapperuma, Cheryl L. Moore
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Patent number: 6235387Abstract: A semiconductor wafer processing tape includes a permanent backing and a layer of a nonpressure sensitive adhesive. The tapes are useful for wafer grinding and/or wafer dicing applications. The nonpressure sensitive adhesive includes a copolymer of at least one of a first monoethylenically unsaturated monomer, at least one of a second monoethylenically unsaturated monomer, and at least one copolymerizable nonionic crosslinking agent; wherein the second monoethylenically unsaturated monomer is a reinforcing monomer having a homopolymer glass transition temperature higher than that of the first monoethylenically unsaturated monomer. A method of processing semiconductor wafers is also provided.Type: GrantFiled: March 30, 1998Date of Patent: May 22, 2001Assignee: 3M Innovative Properties CompanyInventors: Richard E. Bennett, Louis E. Winslow, Greggory S. Bennett, Karunasena A. Alahapperuma, Cheryl L. Moore
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Patent number: 6027778Abstract: The present invention provides a novel one-piece capstan for a tape cartridge which provides good static dissipative properties and wear resistance. The capstan material of the present invention has a charge decay time of no more than 5 seconds as measured according to Mil B-81705C standard. The capstan material also has a flexural modulus of at least 200,000 psi (1379 MPa). The capstan comprises a hard, dimensionally stable polymer and a static dissipating polymer. The capstan also has an improved structure and geometry which enables the part to be easily molded, reduces drive force requirements with a reduction of material from the prior art design, but with no significant loss of performance properties.Type: GrantFiled: September 15, 1994Date of Patent: February 22, 2000Assignee: Imation Corp.Inventors: Karunasena A. Alahapperuma, Anthony B. Ferguson, David P. Smith, David L. Tussey, Saurin J. Shah, Dean E. Sitz, Randy S. Bay, Daniel C. Egan, Wolfgang G. Schoeppel