Patents by Inventor Mahadevaiyer Krishnan
Mahadevaiyer Krishnan 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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Publication number: 20140305499Abstract: A method for forming a photovoltaic device includes forming an absorber layer with a granular structure on a conductive layer; conformally depositing an insulating protection layer over the absorber layer to fill in between grains of the absorber layer; and planarizing the protection layer and the absorber layer. A buffer layer is formed on the absorber layer, and a top transparent conductor layer is deposited over the buffer layer.Type: ApplicationFiled: August 16, 2013Publication date: October 16, 2014Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Talia S. Gershon, Supratik Guha, Jeehwan Kim, Mahadevaiyer Krishnan, Byungha Shin
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Publication number: 20140306306Abstract: A method for forming a photovoltaic device includes forming an absorber layer with a granular structure on a conductive layer; conformally depositing an insulating protection layer over the absorber layer to fill in between grains of the absorber layer; and planarizing the protection layer and the absorber layer. A buffer layer is formed on the absorber layer, and a top transparent conductor layer is deposited over the buffer layer.Type: ApplicationFiled: April 12, 2013Publication date: October 16, 2014Applicant: International Business Machines CorporationInventors: Talia S. Gershon, Supratik Guha, Jeehwan Kim, Mahadevaiyer Krishnan, Byungha Shin
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Patent number: 8815475Abstract: A reticle carrier for a polishing tool capable of accommodating a reticle includes a base plate with an obverse and reverse surfaces, a retaining ring secured to the obverse surface of the base plate forming a recess defined by the obverse surface of the rigid base plate and internal edges of the retaining ring. A reticle pad supports a reticle in the recess. The base plate and the reticle pad having an array of matching, aligned passageway holes therethrough for exhaustion of air from space between the base plate and a the reticle and for supply of air to that space so a vacuum can retain a the reticle in place on the reticle carrier under vacuum conditions and application of air under pressure can eject a reticle from the reticle carrier.Type: GrantFiled: January 7, 2013Date of Patent: August 26, 2014Assignee: International Business Machines CorporationInventors: Kevin S. Petrarca, Donald F. Canaperi, Mahadevaiyer Krishnan, Rebecca D. Mih, Steven Steen, Henry Grabarz, Michael S. Hibbs
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Publication number: 20140051201Abstract: A method of texturing a surface of a crystalline silicon substrate is provided. The method includes immersing a crystalline silicon substrate into an aqueous alkaline etchant solution to form a pyramid shaped textured surface, with (111) faces exposed, on the crystalline silicon substrate. The aqueous alkaline etchant solution employed in the method of the present disclosure includes an alkaline component and a nanoparticle slurry component. Specifically, the aqueous alkaline etchant solution of the present disclosure includes 0.5 weight percent to 5 weight percent of an alkaline component and from 0.1 weight percent to 5 weight percent of a nanoparticle slurry on a dry basis.Type: ApplicationFiled: October 22, 2013Publication date: February 20, 2014Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Mahadevaiyer Krishnan, Jun Liu, Satyavolu S. Papa Rao, George G. Totir
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Publication number: 20140042360Abstract: A method of texturing a surface of a crystalline silicon substrate is provided. The method includes immersing a crystalline silicon substrate into an aqueous alkaline etchant solution to form a pyramid shaped textured surface, with (111) faces exposed, on the crystalline silicon substrate. The aqueous alkaline etchant solution employed in the method of the present disclosure includes an alkaline component and a nanoparticle slurry component. Specifically, the aqueous alkaline etchant solution of the present disclosure includes 0.5 weight percent to 5 weight percent of an alkaline component and from 0.1 weight percent to 5 weight percent of a nanoparticle slurry on a dry basis.Type: ApplicationFiled: October 22, 2013Publication date: February 13, 2014Applicant: International Business Machines CorporationInventors: Mahadevaiyer Krishnan, Jun Liu, Satyavolu S. Papa Rao, George G. Totir
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Patent number: 8637405Abstract: A method of texturing a surface of a crystalline silicon substrate is provided. The method includes immersing a crystalline silicon substrate into an aqueous alkaline etchant solution to form a pyramid shaped textured surface, with (111) faces exposed, on the crystalline silicon substrate. The aqueous alkaline etchant solution employed in the method of the present disclosure includes an alkaline component and a nanoparticle slurry component. Specifically, the aqueous alkaline etchant solution of the present disclosure includes 0.5 weight percent to 5 weight percent of an alkaline component and from 0.1 weight percent to 5 weight percent of a nanoparticle slurry on a dry basis.Type: GrantFiled: June 21, 2011Date of Patent: January 28, 2014Assignee: International Business Machines CorporationInventors: Mahadevaiyer Krishnan, Jun Liu, Satyavolu S. Papa Rao, George G. Totir
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Publication number: 20130316623Abstract: An apparatus for chemical mechanical planarization includes a spindle assembly structure and at least one substrate carrier, which make a linear lateral movement relative to each other while abrasive surfaces of a plurality of cylindrical spindles in the spindle assembly structure contact, and rotate against, at least one substrate mounted on the at least one substrate carrier. The direction of the linear lateral movement is within the plane that tangentially contacts the plurality of cylindrical spindles, and can be orthogonal to the axes of rotation of the plurality of cylindrical spindles.Type: ApplicationFiled: August 5, 2013Publication date: November 28, 2013Applicant: International Business Machines CorporationInventors: Michael A. Cobb, Mahadevaiyer Krishnan, Michael F. Lofaro, Dennis G. Manzer
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Patent number: 8591289Abstract: An apparatus for chemical mechanical planarization includes a spindle assembly structure and at least one substrate carrier, which make a linear lateral movement relative to each other while abrasive surfaces of a plurality of cylindrical spindles in the spindle assembly structure contact, and rotate against, at least one substrate mounted on the at least one substrate carrier. The direction of the linear lateral movement is within the plane that tangentially contacts the plurality of cylindrical spindles, and can be orthogonal to the axes of rotation of the plurality of cylindrical spindles.Type: GrantFiled: September 6, 2012Date of Patent: November 26, 2013Assignee: International Business Machines CorporationInventors: Michael A. Cobb, Mahadevaiyer Krishnan, Michael F. Lofaro, Dennis G. Manzer
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Patent number: 8535118Abstract: An apparatus for chemical mechanical planarization includes a spindle assembly structure and at least one substrate carrier, which make a linear lateral movement relative to each other while abrasive surfaces of a plurality of cylindrical spindles in the spindle assembly structure contact, and rotate against, at least one substrate mounted on the at least one substrate carrier. The direction of the linear lateral movement is within the plane that tangentially contacts the plurality of cylindrical spindles, and can be orthogonal to the axes of rotation of the plurality of cylindrical spindles.Type: GrantFiled: September 20, 2011Date of Patent: September 17, 2013Assignee: International Business Machines CorporationInventors: Michael A. Cobb, Mahadevaiyer Krishnan, Michael F. Lofaro, Dennis G. Manzer
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Patent number: 8524606Abstract: Planarization methods include depositing a mask material on top of an overburden layer on a semiconductor wafer. The mask material is planarized to remove the mask material from up areas of the overburden layer to expose the overburden layer without removing the mask material from down areas. The exposed overburden layer is wet etched and leaves a thickness remaining over an underlying layer. Remaining portions of the mask layer and the exposed portions of the overburden layer are planarized to expose the underlying layer.Type: GrantFiled: January 25, 2011Date of Patent: September 3, 2013Assignees: International Business Machines Corporation, JSR CorporationInventors: Leslie Charns, John M. Cotte, Jason E. Cummings, Lukasz J. Hupka, Dinesh R. Koli, Tomohisa Konno, Mahadevaiyer Krishnan, Michael F. Lofaro, Jakub W. Nalaskowski, Masahiro Noda, Dinesh K. Penigalapati, Tatsuya Yamanaka
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Patent number: 8513127Abstract: A planarization method includes planarizing a semiconductor wafer in a first chemical mechanical polish step to remove overburden and planarize a top layer leaving a thickness of top layer material over underlying layers. The top layer material is planarized in a second chemical mechanical polish step to further remove the top layer and expose underlying layers of a second material and a third material such that a selectivity of the top layer material to the second material to the third material is between about 1:1:1 to about 2:1:1 to provide a planar topography.Type: GrantFiled: January 25, 2011Date of Patent: August 20, 2013Assignees: International Business Machines Corporation, JSR CorporationInventors: Josephine B. Chang, Leslie Charns, Jason E. Cummings, Michael A. Guillorn, Lukasz J. Hupka, Dinesh R. Koli, Tomohisa Konno, Mahadevaiyer Krishnan, Michael F. Lofaro, Jakub W. Nalaskowski, Masahiro Noda, Dinesh K. Penigalapati, Tatsuya Yamanaka
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Patent number: 8507383Abstract: Methods for polishing multiple dielectric layers to form replacement metal gate structures include a first chemical mechanical polish step to remove overburden and planarize a top layer to leave a planarized thickness over a gate structure. A second chemical mechanical polish step includes removal of the thickness to expose an underlying covered surface of a dielectric of the gate structure with a slurry configured to polish the top layer and the underlying covered surface substantially equally to accomplish a planar topography. A third chemical mechanical polish step is employed to remove the dielectric of the gate structure and expose a gate conductor.Type: GrantFiled: January 25, 2011Date of Patent: August 13, 2013Assignees: International Business Machines Corporation, JRS CorporationInventors: Takashi Ando, Leslie Charns, Jason E. Cummings, Lukasz J. Hupka, Dinesh R. Koli, Tomohisa Konno, Mahadevaiyer Krishnan, Michael F. Lofaro, Jakub W. Nalaskowski, Masahiro Noda, Dinesh K. Penigalapati, Tatsuya Yamanaka
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Patent number: 8497210Abstract: A polishing method includes polishing, in a first polish, a wafer to remove overburden and planarize a top layer leaving a portion remaining on an underlying layer. A second polishing step includes two phases. In a first phase, the top layer is removed and the underlying layer is exposed, with a top layer to underlying layer selectivity of between about 1:1 to about 2:1 to provide a planar topography. In a second phase, residual portions of the top layer are removed from a top of the underlying layer to ensure complete exposure of an underlying layer surface.Type: GrantFiled: January 24, 2011Date of Patent: July 30, 2013Assignees: International Business Machines Corporation, JRS CorporationInventors: Leslie Charns, Jason E. Cummings, Lukasz J. Hupka, Dinesh R. Koli, Tomohisa Konno, Mahadevaiyer Krishnan, Michael F. Lofaro, Jakub W. Nalaskowski, Masahiro Noda, Dinesh K. Penigalapati, Tatsuya Yamanaka
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Patent number: 8439728Abstract: A reticle carrier for a polishing tool capable of accommodating a reticle includes a base plate with an obverse and reverse surfaces, a retaining ring secured to the obverse surface of the base plate forming a recess defined by the obverse surface of the rigid base plate and internal edges of the retaining ring. A reticle pad supports a reticle in the recess. The base plate and the reticle pad having an array of matching, aligned passageway holes therethrough for exhaustion of air from space between the base plate and a the reticle and for supply of air to that space so a vacuum can retain a the reticle in place on the reticle carrier under vacuum conditions and application of air under pressure can eject a reticle from the reticle carrier.Type: GrantFiled: October 21, 2011Date of Patent: May 14, 2013Assignee: International Business Machines CorporationInventors: Kevin S. Petrarca, Donald F. Canaperi, Mahadevaiyer Krishnan, Rebecca D. Mih, Steven Steen, Henry Grabarz, Michael S. Hibbs
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Publication number: 20130072089Abstract: An apparatus for chemical mechanical planarization includes a spindle assembly structure and at least one substrate carrier, which make a linear lateral movement relative to each other while abrasive surfaces of a plurality of cylindrical spindles in the spindle assembly structure contact, and rotate against, at least one substrate mounted on the at least one substrate carrier. The direction of the linear lateral movement is within the plane that tangentially contacts the plurality of cylindrical spindles, and can be orthogonal to the axes of rotation of the plurality of cylindrical spindles.Type: ApplicationFiled: September 20, 2011Publication date: March 21, 2013Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Michael F. Lofaro, Mahadevaiyer Krishnan, Michael A. Cobb, Dennis G. Manzer
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Publication number: 20130072092Abstract: An apparatus for chemical mechanical planarization includes a spindle assembly structure and at least one substrate carrier, which make a linear lateral movement relative to each other while abrasive surfaces of a plurality of cylindrical spindles in the spindle assembly structure contact, and rotate against, at least one substrate mounted on the at least one substrate carrier. The direction of the linear lateral movement is within the plane that tangentially contacts the plurality of cylindrical spindles, and can be orthogonal to the axes of rotation of the plurality of cylindrical spindles.Type: ApplicationFiled: September 6, 2012Publication date: March 21, 2013Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Michael F. Lofaro, Mahadevaiyer Krishnan, Michael A. Cobb, Dennis G. Manzer
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Publication number: 20120329200Abstract: A method of texturing a surface of a crystalline silicon substrate is provided. The method includes immersing a crystalline silicon substrate into an aqueous alkaline etchant solution to form a pyramid shaped textured surface, with (111) faces exposed, on the crystalline silicon substrate. The aqueous alkaline etchant solution employed in the method of the present disclosure includes an alkaline component and a nanoparticle slurry component. Specifically, the aqueous alkaline etchant solution of the present disclosure includes 0.5 weight percent to 5 weight percent of an alkaline component and from 0.1 weight percent to 5 weight percent of a nanoparticle slurry on a dry basis.Type: ApplicationFiled: June 21, 2011Publication date: December 27, 2012Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Mahadevaiyer Krishnan, Jun Liu, Satyavolu S. Papa Rao, George G. Totir
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Publication number: 20120083121Abstract: Methods for polishing multiple dielectric layers to form replacement metal gate structures include a first chemical mechanical polish step to remove overburden and planarize a top layer to leave a planarized thickness over a gate structure. A second chemical mechanical polish step includes removal of the thickness to expose an underlying covered surface of a dielectric of the gate structure with a slurry configured to polish the top layer and the underlying covered surface substantially equally to accomplish a planar topography. A third chemical mechanical polish step is employed to remove the dielectric of the gate structure and expose a gate conductor.Type: ApplicationFiled: January 25, 2011Publication date: April 5, 2012Applicants: JSR CORPORATION, INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Takashi Ando, Leslie Charns, Jason E. Cummings, Lukasz J. Hupka, Dinesh R. Koli, Tomohisa Konno, Mahadevaiyer Krishnan, Michael F. Lofaro, Jakub W. Nalaskowski, Masahiro Noda, Dinesh K. Penigalapati, Tatsuya Yamanaka
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Publication number: 20120083122Abstract: A polishing method includes polishing, in a first polish, a wafer to remove overburden and planarize a top layer leaving a portion remaining on an underlying layer. A second polishing step includes two phases. In a first phase, the top layer is removed and the underlying layer is exposed, with a top layer to underlying layer selectivity of between about 1:1 to about 2:1 to provide a planar topography. In a second phase, residual portions of the top layer are removed from a top of the underlying layer to ensure complete exposure of an underlying layer surface.Type: ApplicationFiled: January 24, 2011Publication date: April 5, 2012Applicants: JSR CORPORATION, INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Leslie Charns, Jason E. Cummings, Lukasz J. Hupka, Dinesh R. Koli, Tomohisa Konno, Mahadevaiyer Krishnan, Michael F. Lofaro, Jakub W. Nalaskowski, Masahiro Noda, Dinesh K. Penigalapati, Tatsuya Yamanaka
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Publication number: 20120083123Abstract: A planarization method includes planarizing a semiconductor wafer in a first chemical mechanical polish step to remove overburden and planarize a top layer leaving a thickness of top layer material over underlying layers. The top layer material is planarized in a second chemical mechanical polish step to further remove the top layer and expose underlying layers of a second material and a third material such that a selectivity of the top layer material to the second material to the third material is between about 1:1:1 to about 2:1:1 to provide a planar topography.Type: ApplicationFiled: January 25, 2011Publication date: April 5, 2012Applicants: JSR CORPORATION, INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Josephine B. Chang, Leslie Charns, Jason E. Cummings, Michael A. Guillorn, Lukasz J. Hupka, Dinesh R. Koli, Tomohisa Konno, Mahadevaiyer Krishnan, Michael F. Lofaro, Jakub W. Nalaskowski, Masahiro Noda, Dinesh K. Penigalapati, Tatsuya Yamanaka