Patents by Inventor Krishnan Shrinivasan
Krishnan Shrinivasan 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: 9873946Abstract: The present invention provides improved methods of preparing a low-k dielectric material on a substrate. The methods involve multiple operation ultraviolet curing processes in which UV intensity, wafer substrate temperature, UV spectral distribution, and other conditions may be independently modulated in each operation. Operations may be pulsed or even be concurrently applied to the same wafer. In certain embodiments, a film containing a structure former and a porogen is exposed to UV radiation in a first operation to facilitate removal of the porogen and create a porous dielectric film. In a second operation, the film is exposed to UV radiation to increase cross-linking within the porous film.Type: GrantFiled: January 9, 2015Date of Patent: January 23, 2018Assignee: Novellus Systems, Inc.Inventors: Jason Dirk Haverkamp, Dennis M. Hausmann, Kevin M. McLaughlin, Krishnan Shrinivasan, Michael Rivkin, Eugene Smargiassi, Mohamed Sabri
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Patent number: 9835388Abstract: Provided are adaptive heat transfer methods and systems for uniform heat transfer to and from various types of workpieces, such as workpieces employed during fabrication of semiconductor devices, displays, light emitting diodes, and photovoltaic panels. This adaptive approach allows for reducing heat transfer variations caused by deformations of workpieces. Deformation may vary in workpieces depending on types of workpieces, processing conditions, and other variables. Such deformations are hard to anticipate and may be random. Provided systems may change their configurations to account for the conformation of each new workpiece processed. Further, adjustments may be performed continuously of discretely during heat transfer. This flexibility can be employed to improve heat transfer uniformity, achieve uniform temperature profile, reduce deformation, and for various other purposes.Type: GrantFiled: December 28, 2012Date of Patent: December 5, 2017Assignee: Novellus Systems, Inc.Inventors: Keerthi Gowdaru, Krishnan Shrinivasan
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Publication number: 20150114292Abstract: The present invention provides improved methods of preparing a low-k dielectric material on a substrate. The methods involve multiple operation ultraviolet curing processes in which UV intensity, wafer substrate temperature, UV spectral distribution, and other conditions may be independently modulated in each operation. Operations may be pulsed or even be concurrently applied to the same wafer. In certain embodiments, a film containing a structure former and a porogen is exposed to UV radiation in a first operation to facilitate removal of the porogen and create a porous dielectric film. In a second operation, the film is exposed to UV radiation to increase cross-linking within the porous film.Type: ApplicationFiled: January 9, 2015Publication date: April 30, 2015Inventors: Jason Dirk Haverkamp, Dennis M. Hausmann, Kevin M. McLaughlin, Krishnan Shrinivasan, Michael Rivkin, Eugene Smargiassi, Mohamed Sabri
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Patent number: 8980769Abstract: The present invention provides improved methods of preparing a low-k dielectric material on a substrate. The methods involve multiple operation ultraviolet curing processes in which UV intensity, wafer substrate temperature, UV spectral distribution, and other conditions may be independently modulated in each operation. Operations may be pulsed or even be concurrently applied to the same wafer. In certain embodiments, a film containing a structure former and a porogen is exposed to UV radiation in a first operation to facilitate removal of the porogen and create a porous dielectric film. In a second operation, the film is exposed to UV radiation to increase cross-linking within the porous film.Type: GrantFiled: October 25, 2007Date of Patent: March 17, 2015Assignee: Novellus Systems, Inc.Inventors: Jason Haverkamp, Dennis Hausmann, Kevin McLaughlin, Krishnan Shrinivasan, Michael Rivkin, Eugene Smargiassi, Mohamed Sabri
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Patent number: 8951348Abstract: The present invention relates to curing of semiconductor wafers. More particularly, the invention relates to cure chambers containing multiple cure stations, each featuring one or more UV light sources. The wafers are cured by sequential exposure to the light sources in each station. In some embodiments, the wafers remain stationary with respect to the light source during exposure. In other embodiments, there is relative movement between the light source and the wafer during exposure. The invention also provides chambers that may be used to independently modulate the cross-linking, density and increase in stress of a cured material by providing independent control of the wafer temperature and UV intensity.Type: GrantFiled: February 10, 2012Date of Patent: February 10, 2015Assignee: Novellus Systems, Inc.Inventors: Krishnan Shrinivasan, Feng Wang, George Kamian, Steve Gentile, Mark Yam
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Patent number: 8889233Abstract: The present invention addresses provides improved methods of preparing a low-k dielectric material on a substrate. The methods involve multi-step ultraviolet curing processes in which UV intensity, wafer substrate temperature and other conditions may be independently modulated at each step. In certain embodiments, a film containing a structure former and a porogen is exposed to UV radiation in a first step to facilitate removal of the porogen and create a porous dielectric film. In a second step, the film is exposed to UV radiation to increase crosslinking within the porous film. In certain embodiments, the curing takes place in a multi-station UV chamber wherein UV intensity and substrate temperature may be independently controlled at each station.Type: GrantFiled: March 6, 2006Date of Patent: November 18, 2014Assignee: Novellus Systems, Inc.Inventors: Maxim Kelman, Krishnan Shrinivasan, Feng Wang, Victor Lu, Sean Chang, Guangquan Lu
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Publication number: 20140080324Abstract: The present invention addresses provides improved methods of preparing a low-k dielectric material on a substrate. The methods involve multiple operation ultraviolet curing processes in which UV intensity, wafer substrate temperature and other conditions may be independently modulated in each operation. In certain embodiments, a film containing a structure former and a porogen is exposed to UV radiation in a first operation to facilitate removal of the porogen and create a porous dielectric film. In a second operation, the film is exposed to UV radiation to increase cross-linking within the porous film. In certain embodiments, the curing takes place in a multi-station UV chamber wherein UV intensity and substrate temperature may be independently controlled at each station.Type: ApplicationFiled: November 21, 2013Publication date: March 20, 2014Applicant: Novellus Systems, Inc.Inventors: Krishnan Shrinivasan, Michael Rivkin, Eugene Smargiassi, Mohamed Sabri
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Patent number: 8629068Abstract: The present invention addresses provides improved methods of preparing a low-k dielectric material on a substrate. The methods involve multiple operation ultraviolet curing processes in which UV intensity, wafer substrate temperature and other conditions may be independently modulated in each operation. In certain embodiments, a film containing a structure former and a porogen is exposed to UV radiation in a first operation to facilitate removal of the porogen and create a porous dielectric film. In a second operation, the film is exposed to UV radiation to increase cross-linking within the porous film. In certain embodiments, the curing takes place in a multi-station UV chamber wherein UV intensity and substrate temperature may be independently controlled at each station.Type: GrantFiled: May 3, 2013Date of Patent: January 14, 2014Assignee: Novellus Systems, Inc.Inventors: Krishnan Shrinivasan, Michael Rivkin, Eugene Smargiassi, Mohamed Sabri
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Publication number: 20130175005Abstract: Provided are adaptive heat transfer methods and systems for uniform heat transfer to and from various types of workpieces, such as workpieces employed during fabrication of semiconductor devices, displays, light emitting diodes, and photovoltaic panels. This adaptive approach allows for reducing heat transfer variations caused by deformations of workpieces. Deformation may vary in workpieces depending on types of workpieces, processing conditions, and other variables. Such deformations are hard to anticipate and may be random. Provided systems may change their configurations to account for the conformation of each new workpiece processed. Further, adjustments may be performed continuously of discretely during heat transfer. This flexibility can be employed to improve heat transfer uniformity, achieve uniform temperature profile, reduce deformation, and for various other purposes.Type: ApplicationFiled: December 28, 2012Publication date: July 11, 2013Inventors: Keerthi Gowdaru, Krishnan Shrinivasan
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Patent number: 8454750Abstract: The present invention addresses provides improved methods of preparing a low-k dielectric material on a substrate. The methods involve multiple operation ultraviolet curing processes in which UV intensity, wafer substrate temperature and other conditions may be independently modulated in each operation. In certain embodiments, a film containing a structure former and a porogen is exposed to UV radiation in a first operation to facilitate removal of the porogen and create a porous dielectric film. In a second operation, the film is exposed to UV radiation to increase cross-linking within the porous film. In certain embodiments, the curing takes place in a multi-station UV chamber wherein UV intensity and substrate temperature may be independently controlled at each station.Type: GrantFiled: March 20, 2007Date of Patent: June 4, 2013Assignee: Novellus Systems, Inc.Inventors: Krishnan Shrinivasan, Michael Rivkin, Eugene Smargiassi, Mohamed Sabri
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Patent number: 7941039Abstract: Provided herein are assemblies that, when coupled to an object, are capable of keeping the object at a uniform elevated temperature while removing large amounts of heat from an external source. Applications include various integrated circuit fabrication processes that use such external sources to expose wafers to radiation. In certain embodiments, the assemblies include a pedestal for supporting the wafer or other object. In certain embodiments, the assemblies include a calibrated heat resistance that allows heat be conducted away from the pedestal and wafer to maintain the desired set-point temperature. In certain embodiments, the pedestal may have one or more protrusions used to dissipate or transfer heat from the pedestal to a heat sink. Also, in certain embodiments, the pedestal surface is configured to have a spectral reflectivity of desired values in such way as to reflect the wavelengths that are emitted by an external radiant heat source.Type: GrantFiled: September 6, 2007Date of Patent: May 10, 2011Assignee: Novellus Systems, Inc.Inventors: Krishnan Shrinivasan, Stephen V. Gentile, Peter Woytowitz, Sassan Roham, George Kamian, Michael Rivkin
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Patent number: 7503334Abstract: A system is provided for cleaning wafers that includes specialized pressurization, process vessel, recirculation, chemical addition, depressurization, and recapture-recycle subsystems. A solvent delivery mechanism converts a liquid-state sub-critical solution to a supercritical cleaning solution and introduces it into a process vessel that contains a wafer or wafers. The supercritical cleaning solution is recirculated through the process vessel by a recirculation system. An additive delivery system introduces chemical additives to the supercritical cleaning solution via the solvent delivery mechanism, the process vessel, or the recirculation system. Addition of chemical additives to the sub-critical solution may also be performed. The recirculation system provides efficient mixing of chemical additives, efficient cleaning, and process uniformity. A depressurization system provides dilution and removal of cleaning solutions under supercritical conditions.Type: GrantFiled: January 6, 2005Date of Patent: March 17, 2009Assignee: Novellus Systems, Inc.Inventors: Krishnan Shrinivasan, Souvik Banerjee, Francisco Juarez, Karen A. Reinhardt, Sanjay Gopinath
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Publication number: 20080264443Abstract: The present invention pertains to a system for processing semiconductor wafers. The processing may involve the removal of material from the wafers or deposition of material on the wafers. Various aspects of the invention include specialized pressurization, process vessel, recirculation, chemical addition, depressurization, and recapture-recycle subsystems. A solvent delivery mechanism can convert a liquid-state sub-critical solution to a supercritical processing solution and introduce it into a process vessel that contains a batch of wafers. The wafers may be rotated within the supercritical processing solution. The supercritical processing solution is preferably recirculated through the process vessel by a recirculation system. When chemical additives are added to a supercritical solvent, the momentum of the chemical additives are preferably matched to the momentum of the supercritical solvent. Additives may be added at a higher initial flow rate, then ramped down a lower flow rate, e.g.Type: ApplicationFiled: January 5, 2004Publication date: October 30, 2008Inventors: Krishnan Shrinivasan, Wilbert G.M. van den Hoek, Patrick Joyce, Thomas Pratt, Tim Thomas
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Patent number: 7327948Abstract: The present invention provides a heat transfer assembly that, when coupled to an object, is capable of keeping the object at a uniform elevated temperature while removing large amounts of heat from an external source. The assembly may be contained in a pedestal for use in a UV-cure chamber. The heat transfer assembly includes a heating element to control the wafer temperature and a cooling element to remove incident IR heat from the wafer and pedestal. A heat resistant layer having a calibrated heat resistance is located between the heating and cooling elements and between the wafer and the cooling elements. The heat resistant layer is able to sustain high temperature gradient from the wafer to the coolant so that the coolant does not boil while permitting enough heat to be conducted away from the wafer to maintain the desired set-point temperature.Type: GrantFiled: July 18, 2005Date of Patent: February 5, 2008Assignee: Novellus Systems, Inc.Inventors: Krishnan Shrinivasan, Stephen Gentile, Peter Woytowitz, Sassan Roham, George Kamian
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Patent number: 7105061Abstract: Methods and an apparatus for providing an intrinsically safe chamber door for a processing chamber capable of operating at high pressures are provided. One exemplary apparatus includes a processing chamber for a substrate where the chamber is configured to operate at a positive pressure. The processing chamber includes a port loading slot for providing access for the substrate into and out of the chamber. A chamber door positioned inside the chamber is included. The chamber door is configured to seal against an internal surface of the chamber thereby blocking access through the port loading slot. An internal pressure of the chamber assists in sealing the chamber door against the internal surface of the chamber. Also included is a door actuating mechanism configured to move the door along a door path where the door path is positioned at an angle to a path to be traversed by the substrate.Type: GrantFiled: November 7, 2001Date of Patent: September 12, 2006Assignee: Novellus Systems, Inc.Inventors: Krishnan Shrinivasan, Arkadiy Shimanovich, Vladimir Starov
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Patent number: 6905556Abstract: A method of delivering a reagent to a wafer is provided. A solvent is provided. A set of conditions of temperature and pressure is provided to the solvent, which is sufficient to bring the solvent to supercritical conditions. A reagent is provided. A surfactant is provided, where the surfactant has a first moiety with an affinity for the solvent and a second moiety with an affinity for the reagent, where the surfactant increases the concentration of the reagent that may be carried by the solvent. The solvent, surfactant, and reagent are combined to form a solution. The solution is delivered to a supercritical process chamber, wherein a wafer is exposed to the solution in the process chamber.Type: GrantFiled: November 27, 2002Date of Patent: June 14, 2005Assignee: Novellus Systems, Inc.Inventors: Raashina Humayun, Patrick C. Joyce, Adrianne Kay Tipton, Krishnan Shrinivasan, Dennis W. Hess, Satyanarayana Myneni, Souvik Banerjee
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Patent number: 6848458Abstract: The present invention pertains to a system for cleaning wafers that includes specialized pressurization, process vessel, recirculation, chemical addition, depressurization, and recapture-recycle subsystems, as well as methods for implementing wafer cleaning using such a system. A solvent delivery mechanism converts a liquid-state sub-critical solution to a supercritical cleaning solution and introduces it into a process vessel that contains a wafer or wafers. The supercritical cleaning solution is recirculated through the process vessel by a recirculation system. An additive delivery system introduces chemical additives to the supercritical cleaning solution via the solvent delivery mechanism, the process vessel, or the recirculation system. Addition of chemical additives to the sub-critical solution may also be performed. The recirculation system provides efficient mixing of chemical additives, efficient cleaning, and process uniformity.Type: GrantFiled: February 5, 2002Date of Patent: February 1, 2005Assignee: Novellus Systems, Inc.Inventors: Krishnan Shrinivasan, Souvik Banerjee, Francisco Juarez, Karen A. Reinhardt, Sanjay Gopinath
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Patent number: 6848455Abstract: Contaminants are removed from a semiconductor wafer by the in-situ generation of oxidizing species. These active species are generated by the simultaneous application of ultra-violet radiation and chemicals containing oxidants such as hydrogen peroxide and dissolved ozone. Ultrasonic or megasonic agitation is employed to facilitate removal. Radicals are generated in-situ, thus generating them close to the semiconductor substrate. The process chamber has a means of introducing both gaseous and liquid reagents, through a gas inlet, and a liquid inlet. O2, O3, and H2O vapor gases are introduced through the gas inlet. H2O and H2O2 liquids are introduced through the liquid inlet. Other liquids such as ammonium hydroxide (NH4OH), hydrochloric acid (HCI), hydrofluoric acid (HF), and the like, may be introduced to further constitute those elements of the traditional RCA clean. The chemicals are premixed in a desired ration and to a predetermined level of dilution prior to being introduced into the chamber.Type: GrantFiled: April 22, 2002Date of Patent: February 1, 2005Assignee: Novellus Systems, Inc.Inventors: Krishnan Shrinivasan, Adrianne Tipton
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Patent number: 6800142Abstract: Methods for cleaning semiconductor wafers are presented. Contaminants, particularly photoresist and post-etch residue, are removed from semiconductor wafers. A wafer or wafers is first treated with a peroxide-containing medium, for example, to oxidatively cleave bond structures of contaminants on the wafer work surface. Excitation energy is used to activate the peroxide-containing medium toward the formation of radical species. After treatment with the peroxide-containing medium, a supercritical fluid treatment is used to remove any remaining contaminants as well as to condition the wafer for subsequent processing.Type: GrantFiled: May 30, 2002Date of Patent: October 5, 2004Assignee: Novellus Systems, Inc.Inventors: Adrianne Kay Tipton, Krishnan Shrinivasan, Souvik Banerjee, Raashina Humayun, Patrick Christopher Joyce
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Patent number: 6764552Abstract: Disclosed formulations of supercritical solutions are useful in wafer cleaning processes. Supercritical solutions of the invention may be categorized by their chemistry, for example, basic, acidic, oxidative, and fluoride chemistries are used. Such solutions may include supercritical carbon dioxide and at least one reagent dissolved therein to facilitate removal of waste material from wafers, particularly for removing photoresist and post-etch residues from low-k materials. This reagent may include an ammonium carbonate or bicarbonate, and combinations of such reagents. The solution may include one or more co-solvents, chelating agents, surfactants, and anti-corrosion agents as well.Type: GrantFiled: November 21, 2002Date of Patent: July 20, 2004Assignee: Novellus Systems, Inc.Inventors: Patrick C. Joyce, Adrianne Tipton, Krishnan Shrinivasan, Dennis W. Hess, Satyanarayana Myneni, Galit Levitin