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).
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Patent number: 7964542Abstract: 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: GrantFiled: January 12, 2006Date of Patent: June 21, 2011Assignee: International Business Machines CorporationInventors: 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
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Patent number: 7608295Abstract: 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: GrantFiled: March 12, 2007Date of Patent: October 27, 2009Assignee: International Business Machines CorporationInventors: Krishna G Sachdev, Michael Berger, Gregg Monjeau, Robert A. Rita, Kathleen M Wiley
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Patent number: 7405247Abstract: 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: GrantFiled: July 31, 2007Date of Patent: July 29, 2008Assignee: International Business Machines CorporationInventors: Krishna G. Sachdev, Daniel George Berger, Kelly May Chioujones, Glenn Graham Daves, Hilton T. Toy
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Patent number: 7393419Abstract: 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: GrantFiled: July 31, 2007Date of Patent: July 1, 2008Assignee: International Business Machines CorporationInventors: Krishna G. Sachdev, Daniel George Berger, Kelly May Chioujones, Glenn Graham Daves, Hilton T. Toy
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Patent number: 7329439Abstract: 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: GrantFiled: September 29, 2004Date of Patent: February 12, 2008Assignee: International Business Machines CorporationInventors: Krishna G. Sachdev, Daniel G. Berger, Kelly M. Chioujones, Brian W. Quinlan
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Patent number: 7312261Abstract: 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: GrantFiled: May 11, 2004Date of Patent: December 25, 2007Assignee: International Business Machines CorporationInventors: Krishna G. Sachdev, Daniel George Berger, Kelly May Chioujones, Glenn Graham Daves, Hilton T. Toy
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Patent number: 6800141Abstract: 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: GrantFiled: December 21, 2001Date of Patent: October 5, 2004Assignee: International Business Machines CorporationInventors: Krishna G. Sachdev, Chon C. Lei, Demian M. Riccardi
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Publication number: 20040132900Abstract: 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: ApplicationFiled: January 8, 2003Publication date: July 8, 2004Applicant: International Business Machines CorporationInventors: Krishna G. Sachdev, Michael Berger, Gregg Monjeau, Robert A. Rita, Kathleen M. Wiley
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Patent number: 6742530Abstract: 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: GrantFiled: November 14, 2002Date of Patent: June 1, 2004Assignee: International Business Machines CorporationInventors: Krishna G. Sachdev, James N. Humenik, Chon Cheong Lei, Glenn A. Pomerantz
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Patent number: 6682872Abstract: 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: GrantFiled: January 22, 2002Date of Patent: January 27, 2004Assignee: International Business Machines CorporationInventors: Krishna G. Sachdev, Michael Berger, Rebecca Y. Gorrell, Gregg B. Monjeau, Bernadette H. Perry, Thomas A. Wassick
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Patent number: 6652665Abstract: 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: GrantFiled: May 31, 2002Date of Patent: November 25, 2003Assignee: International Business Machines CorporationInventors: Krishna G. Sachdev, Umar M. Ahmad, Chon C. Lei
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Publication number: 20030138733Abstract: 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: ApplicationFiled: January 22, 2002Publication date: July 24, 2003Applicant: International Business Machines CorporationInventors: Krishna G. Sachdev, Michael Berger, Rebecca Y. Gorrell, Gregg B. Monjeau, Bernadette H. Perry, Thomas A. Wassick
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Patent number: 6597058Abstract: 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: GrantFiled: August 9, 1999Date of Patent: July 22, 2003Assignee: International Business Machines CorporationInventors: Govindarajan Natarajan, Richard F. Indyk, Vincent P. Peterson, Krishna G. Sachdev
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Publication number: 20030121529Abstract: 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: ApplicationFiled: December 21, 2001Publication date: July 3, 2003Inventors: Krishna G. Sachdev, Chon C. Lei, Demian M. Riccardi
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Publication number: 20030116173Abstract: 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: ApplicationFiled: December 21, 2001Publication date: June 26, 2003Applicant: International Business Machines CorporationInventors: James N, Humenik, Tuyen Hong Nguyen, George R. Proto, Demian M. Riccardi, Krishna G. Sachdev, Krystyna W. Semkow
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Patent number: 6569252Abstract: 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: GrantFiled: June 30, 2000Date of Patent: May 27, 2003Assignee: International Business Machines CorporationInventors: Krishna G. Sachdev, James N. Humenik, Chon Cheong Lei, Glenn A. Pomerantz
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Patent number: 6548175Abstract: 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: GrantFiled: January 11, 2001Date of Patent: April 15, 2003Assignee: International Business Machines CorporationInventors: Krishna G. Sachdev, Raymond A. Jackson, Amy B. Ostrander, Charles H. Perry, Megan J. Shannon
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Publication number: 20030066540Abstract: 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: ApplicationFiled: November 14, 2002Publication date: April 10, 2003Applicant: International Business Machines CorporationInventors: Krishna G. Sachdev, James N. Humenik, Chon Cheong Lei, Glenn A. Pomerantz
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Patent number: 6528145Abstract: 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: GrantFiled: June 29, 2000Date of Patent: March 4, 2003Assignee: International Business Machines CorporationInventors: Daniel George Berger, Shaji Farooq, Lester Wynn Herron, James N. Humenik, John Ulrich Knickerbocker, Robert William Pasco, Charles H. Perry, Krishna G. Sachdev
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Patent number: 6525009Abstract: 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: GrantFiled: December 7, 2000Date of Patent: February 25, 2003Assignee: International Business Machines CorporationInventors: Krishna G. Sachdev, Glenn A. Pomerantz, Daniel S. Mackin