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).

  • Patent number: 8038750
    Abstract: 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: Grant
    Filed: July 13, 2007
    Date of Patent: October 18, 2011
    Assignee: 3M Innovative Properties Company
    Inventors: Joseph G Pribyl, Karunasena Alahapperuma, Craig F. Lamphere, Edward J. Woo
  • Publication number: 20090017727
    Abstract: 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: Application
    Filed: July 13, 2007
    Publication date: January 15, 2009
    Inventors: Joseph G. Pribyl, Karunasena Alahapperuma, Craig F. Lamphere, Edward J. Woo
  • Patent number: 6759121
    Abstract: 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: Grant
    Filed: December 11, 2001
    Date of Patent: July 6, 2004
    Assignee: 3M Innovative Properties Company
    Inventors: Karunasena A. Alahapperuma, Peter A. Stark
  • Publication number: 20030108738
    Abstract: 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: Application
    Filed: December 11, 2001
    Publication date: June 12, 2003
    Applicant: 3M Innovative Properties Company
    Inventors: Karunasena A. Alahapperuma, Peter A. Stark
  • Patent number: 6478918
    Abstract: 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: Grant
    Filed: January 18, 2001
    Date of Patent: November 12, 2002
    Assignee: 3M Innovative Properties Company
    Inventors: Richard E. Bennett, Louis E. Winslow, Greggory S. Bennett, Karunasena A. Alahapperuma, Cheryl L. Moore
  • Patent number: 6472065
    Abstract: 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: Grant
    Filed: July 13, 2000
    Date of Patent: October 29, 2002
    Assignee: 3M Innovative Properties Company
    Inventors: Karunasena A. Alahapperuma, Steven S. Kantner
  • Publication number: 20010016257
    Abstract: 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: Application
    Filed: January 18, 2001
    Publication date: August 23, 2001
    Applicant: 3M Innovative Properties Company
    Inventors: Richard E. Bennett, Louis E. Winslow, Greggory S. Bennett, Karunasena A. Alahapperuma, Cheryl L. Moore
  • Patent number: 6235387
    Abstract: 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: Grant
    Filed: March 30, 1998
    Date of Patent: May 22, 2001
    Assignee: 3M Innovative Properties Company
    Inventors: Richard E. Bennett, Louis E. Winslow, Greggory S. Bennett, Karunasena A. Alahapperuma, Cheryl L. Moore
  • Patent number: 6027778
    Abstract: 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: Grant
    Filed: September 15, 1994
    Date of Patent: February 22, 2000
    Assignee: 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