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).

  • Patent number: 9873946
    Abstract: 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: Grant
    Filed: January 9, 2015
    Date of Patent: January 23, 2018
    Assignee: Novellus Systems, Inc.
    Inventors: Jason Dirk Haverkamp, Dennis M. Hausmann, Kevin M. McLaughlin, Krishnan Shrinivasan, Michael Rivkin, Eugene Smargiassi, Mohamed Sabri
  • Patent number: 9835388
    Abstract: 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: Grant
    Filed: December 28, 2012
    Date of Patent: December 5, 2017
    Assignee: Novellus Systems, Inc.
    Inventors: Keerthi Gowdaru, Krishnan Shrinivasan
  • Publication number: 20150114292
    Abstract: 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: Application
    Filed: January 9, 2015
    Publication date: April 30, 2015
    Inventors: Jason Dirk Haverkamp, Dennis M. Hausmann, Kevin M. McLaughlin, Krishnan Shrinivasan, Michael Rivkin, Eugene Smargiassi, Mohamed Sabri
  • Patent number: 8980769
    Abstract: 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: Grant
    Filed: October 25, 2007
    Date of Patent: March 17, 2015
    Assignee: Novellus Systems, Inc.
    Inventors: Jason Haverkamp, Dennis Hausmann, Kevin McLaughlin, Krishnan Shrinivasan, Michael Rivkin, Eugene Smargiassi, Mohamed Sabri
  • Patent number: 8951348
    Abstract: 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: Grant
    Filed: February 10, 2012
    Date of Patent: February 10, 2015
    Assignee: Novellus Systems, Inc.
    Inventors: Krishnan Shrinivasan, Feng Wang, George Kamian, Steve Gentile, Mark Yam
  • Patent number: 8889233
    Abstract: 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: Grant
    Filed: March 6, 2006
    Date of Patent: November 18, 2014
    Assignee: Novellus Systems, Inc.
    Inventors: Maxim Kelman, Krishnan Shrinivasan, Feng Wang, Victor Lu, Sean Chang, Guangquan Lu
  • Publication number: 20140080324
    Abstract: 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: Application
    Filed: November 21, 2013
    Publication date: March 20, 2014
    Applicant: Novellus Systems, Inc.
    Inventors: Krishnan Shrinivasan, Michael Rivkin, Eugene Smargiassi, Mohamed Sabri
  • Patent number: 8629068
    Abstract: 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: Grant
    Filed: May 3, 2013
    Date of Patent: January 14, 2014
    Assignee: Novellus Systems, Inc.
    Inventors: Krishnan Shrinivasan, Michael Rivkin, Eugene Smargiassi, Mohamed Sabri
  • Publication number: 20130175005
    Abstract: 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: Application
    Filed: December 28, 2012
    Publication date: July 11, 2013
    Inventors: Keerthi Gowdaru, Krishnan Shrinivasan
  • Patent number: 8454750
    Abstract: 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: Grant
    Filed: March 20, 2007
    Date of Patent: June 4, 2013
    Assignee: Novellus Systems, Inc.
    Inventors: Krishnan Shrinivasan, Michael Rivkin, Eugene Smargiassi, Mohamed Sabri
  • Patent number: 7941039
    Abstract: 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: Grant
    Filed: September 6, 2007
    Date of Patent: May 10, 2011
    Assignee: Novellus Systems, Inc.
    Inventors: Krishnan Shrinivasan, Stephen V. Gentile, Peter Woytowitz, Sassan Roham, George Kamian, Michael Rivkin
  • Patent number: 7503334
    Abstract: 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: Grant
    Filed: January 6, 2005
    Date of Patent: March 17, 2009
    Assignee: Novellus Systems, Inc.
    Inventors: Krishnan Shrinivasan, Souvik Banerjee, Francisco Juarez, Karen A. Reinhardt, Sanjay Gopinath
  • Publication number: 20080264443
    Abstract: 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: Application
    Filed: January 5, 2004
    Publication date: October 30, 2008
    Inventors: Krishnan Shrinivasan, Wilbert G.M. van den Hoek, Patrick Joyce, Thomas Pratt, Tim Thomas
  • Patent number: 7327948
    Abstract: 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: Grant
    Filed: July 18, 2005
    Date of Patent: February 5, 2008
    Assignee: Novellus Systems, Inc.
    Inventors: Krishnan Shrinivasan, Stephen Gentile, Peter Woytowitz, Sassan Roham, George Kamian
  • Patent number: 7105061
    Abstract: 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: Grant
    Filed: November 7, 2001
    Date of Patent: September 12, 2006
    Assignee: Novellus Systems, Inc.
    Inventors: Krishnan Shrinivasan, Arkadiy Shimanovich, Vladimir Starov
  • Patent number: 6905556
    Abstract: 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: Grant
    Filed: November 27, 2002
    Date of Patent: June 14, 2005
    Assignee: Novellus Systems, Inc.
    Inventors: Raashina Humayun, Patrick C. Joyce, Adrianne Kay Tipton, Krishnan Shrinivasan, Dennis W. Hess, Satyanarayana Myneni, Souvik Banerjee
  • Patent number: 6848458
    Abstract: 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: Grant
    Filed: February 5, 2002
    Date of Patent: February 1, 2005
    Assignee: Novellus Systems, Inc.
    Inventors: Krishnan Shrinivasan, Souvik Banerjee, Francisco Juarez, Karen A. Reinhardt, Sanjay Gopinath
  • Patent number: 6848455
    Abstract: 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: Grant
    Filed: April 22, 2002
    Date of Patent: February 1, 2005
    Assignee: Novellus Systems, Inc.
    Inventors: Krishnan Shrinivasan, Adrianne Tipton
  • Patent number: 6800142
    Abstract: 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: Grant
    Filed: May 30, 2002
    Date of Patent: October 5, 2004
    Assignee: Novellus Systems, Inc.
    Inventors: Adrianne Kay Tipton, Krishnan Shrinivasan, Souvik Banerjee, Raashina Humayun, Patrick Christopher Joyce
  • Patent number: 6764552
    Abstract: 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: Grant
    Filed: November 21, 2002
    Date of Patent: July 20, 2004
    Assignee: Novellus Systems, Inc.
    Inventors: Patrick C. Joyce, Adrianne Tipton, Krishnan Shrinivasan, Dennis W. Hess, Satyanarayana Myneni, Galit Levitin