Patents by Inventor Krishna G. Sachdev

Krishna G. Sachdev 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: 7964542
    Abstract: Liquid compositions containing a specific hindered phenol or a hindered phenol in combination with an aromatic phosphite are provided which are used as a thermal interface between a heatsink and a chip during a test procedure for electronic components which compositions enhance the thermal conductivity between the heatsink and the chip, are easily removed from the heatsink and the chip after the test procedure without any deleterious residue and which allow the use of high temperatures for extended periods during the test procedure without any significant degradation of the composition. A method for using the compositions in electronic component test procedures such as burn-in procedures is also provided.
    Type: Grant
    Filed: January 12, 2006
    Date of Patent: June 21, 2011
    Assignee: International Business Machines Corporation
    Inventors: Krishna G. Sachdev, Harbans Singh Sachdev, legal representative, Mark S. Chace, Normand Cote, David L. Gardell, Jeffrey D. Gelorme, Sushumna Iruvanti, G. John Lawson, Tuknekah M. Noble
  • Patent number: 7608295
    Abstract: A method to repair ceramic substrates is disclosed using a novel polyimide polymer which has high thermal stability, resistance to fluxes and flux residue cleaning solvents and processes, good mechanical properties, good adhesion to all contacting surfaces with low moisture uptake and good flow properties suitable for repairing chipped ceramic, filling deep trench or vias and writing passivation lines with automated process The polyimide polymer is made by reacting aromatic dianhydride and aromatic diamine monomers with a stoichiometric offset and end capping the resulting polymer when the reaction is completed. The preferred polyimide is made using a molar excess of diamine which is end-capped using an anhydride.
    Type: Grant
    Filed: March 12, 2007
    Date of Patent: October 27, 2009
    Assignee: International Business Machines Corporation
    Inventors: Krishna G Sachdev, Michael Berger, Gregg Monjeau, Robert A. Rita, Kathleen M Wiley
  • Patent number: 7405247
    Abstract: A reworkable conductive adhesive composition, comprising an epoxy based conductive adhesive containing conductive metal filler particles dispersed in a solvent-free hybrid epoxy polymer matrix.
    Type: Grant
    Filed: July 31, 2007
    Date of Patent: July 29, 2008
    Assignee: International Business Machines Corporation
    Inventors: Krishna G. Sachdev, Daniel George Berger, Kelly May Chioujones, Glenn Graham Daves, Hilton T. Toy
  • Patent number: 7393419
    Abstract: A method of removing cured conductive polymer adhesives, disclosed here as thermal interface materials, from electronic components for reclamation or recovery of usable parts of module assemblies, particularly high cost semiconductor devices, heat sinks and other module components.
    Type: Grant
    Filed: July 31, 2007
    Date of Patent: July 1, 2008
    Assignee: International Business Machines Corporation
    Inventors: Krishna G. Sachdev, Daniel George Berger, Kelly May Chioujones, Glenn Graham Daves, Hilton T. Toy
  • Patent number: 7329439
    Abstract: Solvent-free UV-curable polymer materials derived from miscible blends of reactive organic monomeric, oligomeric and low molecular polymeric systems and organic and inorganic fillers such as polytetrafluoroethylene and talc are provided to form polymer-filler composite compositions for use in the fabrication and repair of electronic components and microelectronic assembly processes. The composition contains a preformed thermoplastic or elastomeric polymer/oligomer with reactive end groups, a monofunctional and/or bifunctional acrylate monomer, a multifunctional (more than two reactive groups) acrylated/methacrylated monomer, a photoinitiator and a fluorocarbon polymer powder as an organic filler which is preferably PTFE and an inorganic filler such as talc. A nano-filler may also be used as the inorganic filler alone or in combination with another inorganic filler such as talc.
    Type: Grant
    Filed: September 29, 2004
    Date of Patent: February 12, 2008
    Assignee: International Business Machines Corporation
    Inventors: Krishna G. Sachdev, Daniel G. Berger, Kelly M. Chioujones, Brian W. Quinlan
  • Patent number: 7312261
    Abstract: A reworkable conductive adhesive composition, and method of making such, comprising an epoxy based conductive adhesive containing conductive metal filler particles dispersed in a solvent-free hybrid epoxy polymer matrix. In an additional embodiment an improved method of removing cured conductive polymer adhesives, disclosed here as thermal interface materials, from electronic components for reclamation or recovery of usable parts of module assemblies, particularly high cost semiconductor devices, heat sinks and other module components.
    Type: Grant
    Filed: May 11, 2004
    Date of Patent: December 25, 2007
    Assignee: International Business Machines Corporation
    Inventors: Krishna G. Sachdev, Daniel George Berger, Kelly May Chioujones, Glenn Graham Daves, Hilton T. Toy
  • Patent number: 6800141
    Abstract: A semi-aqueous solvent based method using non-aromatic, halogen-free organic solvent compositions for the effective removal of flux residue from electronic component surfaces after high temperature solder interconnections in the presence of rosin based flux compositions. Rosin flux residue can be removed using hydrophobic, essentially water insoluble, propylene glycol alkylether solvents in conjunction with a surfactant, preferably an ionic and/or a mixture of a non-ionic and an ionic surfactant in the first step, then a second step involving immersion with agitation in a hydrophobic solvent with no added surfactant. This is followed by a third step of hydrophilic solvent immersion with agitation/spray, rinsing off the hydrophilic solvent with water, and then a drying step.
    Type: Grant
    Filed: December 21, 2001
    Date of Patent: October 5, 2004
    Assignee: International Business Machines Corporation
    Inventors: Krishna G. Sachdev, Chon C. Lei, Demian M. Riccardi
  • Publication number: 20040132900
    Abstract: A method to repair ceramic substrates is disclosed using a novel polyimide polymer which has high thermal stability, resistance to fluxes and flux residue cleaning solvents and processes, good mechanical properties, good adhesion to all contacting surfaces with low moisture uptake and good flow properties suitable for repairing chipped ceramic, filling deep trench or vias and writing passivation lines with automated process The polyimide polymer is made by reacting aromatic dianhydride and aromatic diamine monomers with a stoichiometric offset and end capping the resulting polymer when the reaction is completed. The preferred polyimide is made using a molar excess of diamine which is end-capped using an anhydride.
    Type: Application
    Filed: January 8, 2003
    Publication date: July 8, 2004
    Applicant: International Business Machines Corporation
    Inventors: Krishna G. Sachdev, Michael Berger, Gregg Monjeau, Robert A. Rita, Kathleen M. Wiley
  • Patent number: 6742530
    Abstract: A process of cleaning of objects that relate to semiconductor fabrication processes, such as, for example, conductive paste screening in the production of multilayer ceramic substrates and composite solder paste by stencil printing in electronic circuit assembly. Specifically, the process removes a metal/polymer composite paste from screening masks and associated paste making and processing equipment used in printing conductive metal pattern onto ceramic green sheet in the fabrication of semiconductor packaging substrates. The process also cleans solder paste residue from stencil printing equipment used in electronic module assembly surface mount technology for SMT discretes, solder column attachment, and BGA (Ball Grid Array) attachment on ceramic chip carrier or for screening solder paste onto printed circuit board.
    Type: Grant
    Filed: November 14, 2002
    Date of Patent: June 1, 2004
    Assignee: International Business Machines Corporation
    Inventors: Krishna G. Sachdev, James N. Humenik, Chon Cheong Lei, Glenn A. Pomerantz
  • Patent number: 6682872
    Abstract: Radiation-curable compositions are provided for use in the fabrication of electronic components as passivation coatings; for defect repair in ceramic and thin film products by micropassivation in high circuit density electronic modules to allow product recovery; as a solder mask in electronic assembly processes; for use as protective coatings on printed circuit board (PCB) circuitry and electronic devices against mechanical damage and corrosion from exposure to the environment. The compositions are solvent-free, radiation-curable, preferably uv-curable, containing a polymer binder, which is a pre-formed thermoplastic or elastomeric polymer/oligomer, a monofunctional and/or bifunctional acrylic monomer, a multifunctional (more than 2 reactive groups) acrylated/methacrylated monomer, and a photoinitiator, where all the constituents are mutually miscible forming a homogeneous viscous blend without the addition of an organic solvent. The compositions may also contain inorganic fillers and/or nanoparticle fillers.
    Type: Grant
    Filed: January 22, 2002
    Date of Patent: January 27, 2004
    Assignee: International Business Machines Corporation
    Inventors: Krishna G. Sachdev, Michael Berger, Rebecca Y. Gorrell, Gregg B. Monjeau, Bernadette H. Perry, Thomas A. Wassick
  • Patent number: 6652665
    Abstract: A method of removing cured silicone polymer deposits from electronic components. The components are immersed in a preheated solution of a quaternary ammonium fluoride in a hydrophobic non-hydroxylic aprotic solvent with agitation. The components are then immersed in a preheated solvent consisting essentially of a hydrophobic aprotic solvent with agitation. This is followed by a rinse and spray of the components with a hydrophilic, essentially water soluble solvent, with agitation. The components are then immersed in a water bath and then rinsed with a pressurized spray of water and then dried with a N2 blow dry.
    Type: Grant
    Filed: May 31, 2002
    Date of Patent: November 25, 2003
    Assignee: International Business Machines Corporation
    Inventors: Krishna G. Sachdev, Umar M. Ahmad, Chon C. Lei
  • Publication number: 20030138733
    Abstract: Radiation-curable compositions are provided for use in the fabrication of electronic components as passivation coatings; for defect repair in ceramic and thin film products by micropassivation in high circuit density electronic modules to allow product recovery; as a solder mask in electronic assembly processes; for use as protective coatings on printed circuit board (PCB) circuitry and electronic devices against mechanical damage and corrosion from exposure to the environment. The compositions are solvent-free, radiation-curable, preferably uv-curable, containing a polymer binder, which is a pre-formed thermoplastic or elastomeric polymer/oligomer, a monofunctional and/or bifunctional acrylic monomer, a multifunctional (more than 2 reactive groups) acrylated/methacrylated monomer, and a photoinitiator, where all the constituents are mutually miscible forming a homogeneous viscous blend without the addition of an organic solvent. The compositions may also contain inorganic fillers and/or nanoparticle fillers.
    Type: Application
    Filed: January 22, 2002
    Publication date: July 24, 2003
    Applicant: International Business Machines Corporation
    Inventors: Krishna G. Sachdev, Michael Berger, Rebecca Y. Gorrell, Gregg B. Monjeau, Bernadette H. Perry, Thomas A. Wassick
  • Patent number: 6597058
    Abstract: This invention relates generally to a new method of forming semiconductor substrates with defect-free surface metallurgical features. In particular, the invention related to a method for providing surface protected ceramic green sheet laminates using at least one thermally depolymerizable surface layer. More particularly, the invention encompasses a method for fabricating semiconductor substrates wherein a thermally depolymerizable/decomposable surface film is placed over a ceramic green sheet stack or assembly prior to lamination and caused to conform to the surface topography of the green sheet during lamination. The invention also encompasses a method for fabricating surface protected green sheet laminates which can be sized or diced without causing process related defects on the ceramic surface.
    Type: Grant
    Filed: August 9, 1999
    Date of Patent: July 22, 2003
    Assignee: International Business Machines Corporation
    Inventors: Govindarajan Natarajan, Richard F. Indyk, Vincent P. Peterson, Krishna G. Sachdev
  • Publication number: 20030121529
    Abstract: A semi-aqueous solvent based method using non-aromatic, halogen-free organic solvent compositions for the effective removal of flux residue from electronic component surfaces after high temperature solder interconnections in the presence of rosin based flux compositions. Rosin flux residue can be removed using hydrophobic, essentially water insoluble, propylene glycol alkylether solvents in conjunction with a surfactant, preferably an ionic and/or a mixture of a non-ionic and an ionic surfactant in the first step, then a second step involving immersion with agitation in a hydrophobic solvent with no added surfactant. This is followed by a third step of hydrophilic solvent immersion with agitation/spray, rinsing off the hydrophilic solvent with water, and then a drying step.
    Type: Application
    Filed: December 21, 2001
    Publication date: July 3, 2003
    Inventors: Krishna G. Sachdev, Chon C. Lei, Demian M. Riccardi
  • Publication number: 20030116173
    Abstract: A process for cleaning paste from a workpiece, such as a screening mask, which includes the step of electrolytically contacting the workpiece with an aqueous solution containing 0.2 to 2 weight percent TMAH. As an optional prestep, the workpiece may be cleaned nonelectrolytically with an aqueous solution containing 0.2 to 2 weight percent TMAH.
    Type: Application
    Filed: December 21, 2001
    Publication date: June 26, 2003
    Applicant: International Business Machines Corporation
    Inventors: James N, Humenik, Tuyen Hong Nguyen, George R. Proto, Demian M. Riccardi, Krishna G. Sachdev, Krystyna W. Semkow
  • Patent number: 6569252
    Abstract: A process of cleaning of objects that relate to semiconductor fabrication processes, such as, for example, conductive paste screening in the production of multilayer ceramic substrates and composite solder paste by stencil printing in electronic circuit assembly. Specifically, the process removes a metal/polymer composite paste from screening masks and associated paste making and processing equipment used in printing conductive metal pattern onto ceramic green sheet in the fabrication of semiconductor packaging substrates. The process also cleans solder paste residue from stencil printing equipment used in electronic module assembly surface mount technology for SMT discretes, solder column attachment, and BGA (Ball Grid Array) attachment on ceramic chip carrier or for screening solder paste onto printed circuit board.
    Type: Grant
    Filed: June 30, 2000
    Date of Patent: May 27, 2003
    Assignee: International Business Machines Corporation
    Inventors: Krishna G. Sachdev, James N. Humenik, Chon Cheong Lei, Glenn A. Pomerantz
  • Patent number: 6548175
    Abstract: The invention is directed to improved conductive adhesives for solder-free interconnections in microelectronic assembly processes such as for chip carrier-to-substrate attachment. These adhesives are characterized by low tensile modulus, low resistivity, high adhesion strength, and durability of these properties during reliability stress conditions of thermal shock, thermal aging, and temperature/humidity (85° C./85%) exposure of the assembled devices. The adhesives contain a homogeneous solution of a siloxane containing epoxide, a curing agent, a curing catalyst and an organic polymeric or oligomeric additive. A conductive filler is added to the solution forming the filler. Preferred fillers are Ag coated with Pd and Ag coated with Au.
    Type: Grant
    Filed: January 11, 2001
    Date of Patent: April 15, 2003
    Assignee: International Business Machines Corporation
    Inventors: Krishna G. Sachdev, Raymond A. Jackson, Amy B. Ostrander, Charles H. Perry, Megan J. Shannon
  • Publication number: 20030066540
    Abstract: The present invention relates generally to a new process of cleaning of objects that relate to semiconductor fabrication processes, such as, for example, conductive paste screening in the production of multilayer ceramic substrates and composite solder paste by stencil printing in electronic circuit assembly. Specifically, this invention is concerned with removing a metal/polymer composite paste from screening masks and associated paste making and processing equipment used in printing conductive metal pattern onto ceramic green sheet in the fabrication of semiconductor packaging substrates. This invention is also concerned with cleaning of solder paste residue from stencil printing equipment used in electronic module assembly surface mount technology for SMT discretes, solder column attachment, and BGA (Ball Grid Array) attachment on ceramic chip carrier or for screening solder paste onto printed circuit board.
    Type: Application
    Filed: November 14, 2002
    Publication date: April 10, 2003
    Applicant: International Business Machines Corporation
    Inventors: Krishna G. Sachdev, James N. Humenik, Chon Cheong Lei, Glenn A. Pomerantz
  • Patent number: 6528145
    Abstract: A composite electronic and/or optical substrate including polymeric and ceramic material wherein the composite substrate has a dielectric constant less than 4 and a coefficient of thermal expansion of 8 to 14 ppm/°C. at 100° C. The composite substrate may be either ceramic-filled polymeric material or polymer-filled ceramic material.
    Type: Grant
    Filed: June 29, 2000
    Date of Patent: March 4, 2003
    Assignee: International Business Machines Corporation
    Inventors: Daniel George Berger, Shaji Farooq, Lester Wynn Herron, James N. Humenik, John Ulrich Knickerbocker, Robert William Pasco, Charles H. Perry, Krishna G. Sachdev
  • Patent number: 6525009
    Abstract: An aqueous alkaline cleaning composition for efficient removal of Mo, Cu, W, or Cu/Ni-based conductive paste residue from screening masks, associated screening equipment and the like by using alkali metal salt and/or tetramethyl ammonium salt of polyacrylic acid, acrylic acid-methacrylic acid co-polymer, polyaspartic acid, polylactic acid, poly(acrylic acid-co-maleic anhydride), poly(maleic acid), with excess alkali for pH adjustment in the range of about 11.5-13.5, and a surfactant which may be a medium foam, low foam or no-foam surfactant, and is preferably an amphoteric and/or non-ionic and/or ionic surfactant.
    Type: Grant
    Filed: December 7, 2000
    Date of Patent: February 25, 2003
    Assignee: International Business Machines Corporation
    Inventors: Krishna G. Sachdev, Glenn A. Pomerantz, Daniel S. Mackin