Patents by Inventor Anand Chandrashekar

Anand Chandrashekar 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: 8623733
    Abstract: Provided are methods of void-free tungsten fill of high aspect ratio features. According to various embodiments, the methods involve a reduced temperature chemical vapor deposition (CVD) process to fill the features with tungsten. In certain embodiments, the process temperature is maintained at less than about 350° C. during the chemical vapor deposition to fill the feature. The reduced-temperature CVD tungsten fill provides improved tungsten fill in high aspect ratio features, provides improved barriers to fluorine migration into underlying layers, while achieving similar thin film resistivity as standard CVD fill. Also provided are methods of depositing thin tungsten films having low-resistivity. According to various embodiments, the methods involve performing a reduced temperature low resistivity treatment on a deposited nucleation layer prior to depositing a tungsten bulk layer and/or depositing a bulk layer via a reduced temperature CVD process followed by a high temperature CVD process.
    Type: Grant
    Filed: April 6, 2010
    Date of Patent: January 7, 2014
    Assignee: Novellus Systems, Inc.
    Inventors: Feng Chen, Raashina Humayun, Michal Danek, Anand Chandrashekar
  • Publication number: 20130330926
    Abstract: Methods and apparatuses for filling high aspect ratio features with tungsten-containing materials in a substantially void-free manner are provided. In certain embodiments, the method involves depositing an initial layer of a tungsten-containing material followed by selectively removing a portion of the initial layer to form a remaining layer, which is differentially passivated along the depth of the high-aspect ration feature. In certain embodiments, the remaining layer is more passivated near the feature opening than inside the feature. The method may proceed with depositing an additional layer of the same or other material over the remaining layer. The deposition rate during this later deposition operation is slower near the feature opening than inside the features due to the differential passivation of the remaining layer. This deposition variation, in turn, may aid in preventing premature closing of the feature and facilitate filling of the feature in a substantially void free manner.
    Type: Application
    Filed: May 6, 2013
    Publication date: December 12, 2013
    Inventors: Anand Chandrashekar, Raashina Humayun, Michal Danek, Aaron R. Fellis, Sean Chang
  • Publication number: 20130302980
    Abstract: Described herein are methods of filling features with tungsten and related systems and apparatus. The methods include inside-out fill techniques as well as conformal deposition in features. Inside-out fill techniques can include selective deposition on etched tungsten layers in features. Conformal and non-conformal etch techniques can be used according to various implementations. The methods described herein can be used to fill vertical features, such as in tungsten vias, and horizontal features, such as vertical NAND (VNAND) word lines. Examples of applications include logic and memory contact fill, DRAM buried word line fill, vertically integrated memory gate/word line fill, and 3-D integration with through-silicon vias (TSVs).
    Type: Application
    Filed: March 27, 2013
    Publication date: November 14, 2013
    Inventors: Anand Chandrashekar, Esther Jeng, Raashina Humayun, Michal Danek, Juwen Gao, Deqi Wang
  • Patent number: 8501620
    Abstract: Top-down methods of increasing reflectivity of tungsten films to form films having high reflectivity, low resistivity and low roughness are provided. The methods involve bulk deposition of tungsten followed by a removing a top portion of the deposited tungsten. In particular embodiments, removing a top portion of the deposited tungsten involve exposing it to a fluorine-containing plasma. The methods produce low resistivity tungsten bulk layers having lower roughness and higher reflectivity. The smooth and highly reflective tungsten layers are easier to photopattern than conventional low resistivity tungsten films. Applications include forming tungsten bit lines.
    Type: Grant
    Filed: March 5, 2012
    Date of Patent: August 6, 2013
    Assignee: Novellus Systems, Inc.
    Inventors: Anand Chandrashekar, Raashina Humayun
  • Publication number: 20130171822
    Abstract: Described herein are methods of filling features with tungsten, and related systems and apparatus, involving inhibition of tungsten nucleation. In some embodiments, the methods involve selective inhibition along a feature profile. Methods of selectively inhibiting tungsten nucleation can include exposing the feature to a direct or remote plasma. In certain embodiments, the substrate can be biased during selective inhibition. Process parameters including bias power, exposure time, plasma power, process pressure and plasma chemistry can be used to tune the inhibition profile. The methods described herein can be used to fill vertical features, such as in tungsten vias, and horizontal features, such as vertical NAND (VNAND) wordlines. The methods may be used for both conformal fill and bottom-up/inside-out fill. Examples of applications include logic and memory contact fill, DRAM buried wordline fill, vertically integrated memory gate/wordline fill, and 3-D integration using through-silicon vias.
    Type: Application
    Filed: February 22, 2013
    Publication date: July 4, 2013
    Inventors: Anand Chandrashekar, Esther Jeng, Raashina Humayun, Michal Danek, Juwen Gao, Deqi Wang
  • Patent number: 8435894
    Abstract: Methods and apparatuses for filling high aspect ratio features with tungsten-containing materials in a substantially void-free manner are provided. In certain embodiments, the method involves depositing an initial layer of a tungsten-containing material followed by selectively removing a portion of the initial layer to form a remaining layer, which is differentially passivated along the depth of the high-aspect ration feature. In certain embodiments, the remaining layer is more passivated near the feature opening than inside the feature. The method may proceed with depositing an additional layer of the same or other material over the remaining layer. The deposition rate during this later deposition operation is slower near the feature opening than inside the features due to the differential passivation of the remaining layer. This deposition variation, in turn, may aid in preventing premature closing of the feature and facilitate filling of the feature in a substantially void free manner.
    Type: Grant
    Filed: January 17, 2012
    Date of Patent: May 7, 2013
    Assignee: Novellus Systems, Inc.
    Inventors: Anand Chandrashekar, Raashina Humayun, Michal Danek, Aaron R. Fellis, Sean Chang
  • Patent number: 8409987
    Abstract: Methods of forming low resistivity tungsten films with good uniformity and good adhesion to the underlying layer are provided. The methods involve forming a tungsten nucleation layer using a pulsed nucleation layer process at low temperature and then treating the deposited nucleation layer prior to depositing the bulk tungsten fill. The treatment operation lowers resistivity of the deposited tungsten film. In certain embodiments, the depositing the nucleation layer involves a boron-based chemistry in the absence of hydrogen. Also in certain embodiments, the treatment operations involve exposing the nucleation layer to alternating cycles of a reducing agent and a tungsten-containing precursor. The methods are useful for depositing films in high aspect ratio and/or narrow features. The films exhibit low resistivity at narrow line widths and excellent step coverage.
    Type: Grant
    Filed: September 23, 2011
    Date of Patent: April 2, 2013
    Assignee: Novellus Systems, Inc.
    Inventors: Anand Chandrashekar, Mirko Glass, Raashina Humayun, Michal Danek, Kaihan Ashtiani, Feng Chen, Lana Hiului Chan, Anil Mane
  • Publication number: 20130005140
    Abstract: A method for filling a recessed feature of a substrate includes a) at least partially filling a recessed feature of a substrate with tungsten-containing film using at least one of chemical vapor deposition (CVD) and atomic layer deposition (ALD); b) at a predetermined temperature, using an etchant including activated fluorine species to selectively etch the tungsten-containing film more than an underlying material of the recessed feature without removing all of the tungsten-containing film at a bottom of the recessed feature; and c) filling the recessed feature using at least one of CVD and ALD.
    Type: Application
    Filed: June 28, 2012
    Publication date: January 3, 2013
    Applicant: Novellus Systems, Inc.
    Inventors: Esther Jeng, Anand Chandrashekar, Raashina Humayun, Michal Danek, Ronald Powell
  • Publication number: 20120164832
    Abstract: Top-down methods of increasing reflectivity of tungsten films to form films having high reflectivity, low resistivity and low roughness are provided. The methods involve bulk deposition of tungsten followed by a removing a top portion of the deposited tungsten. In particular embodiments, removing a top portion of the deposited tungsten involve exposing it to a fluorine-containing plasma. The methods produce low resistivity tungsten bulk layers having lower roughness and higher reflectivity. The smooth and highly reflective tungsten layers are easier to photopattern than conventional low resistivity tungsten films. Applications include forming tungsten bit lines.
    Type: Application
    Filed: March 5, 2012
    Publication date: June 28, 2012
    Inventors: Anand CHANDRASHEKAR, Raashina HUMAYUN
  • Publication number: 20120115329
    Abstract: Methods and apparatuses for filling high aspect ratio features with tungsten-containing materials in a substantially void-free manner are provided. In certain embodiments, the method involves depositing an initial layer of a tungsten-containing material followed by selectively removing a portion of the initial layer to form a remaining layer, which is differentially passivated along the depth of the high-aspect ration feature. In certain embodiments, the remaining layer is more passivated near the feature opening than inside the feature. The method may proceed with depositing an additional layer of the same or other material over the remaining layer. The deposition rate during this later deposition operation is slower near the feature opening than inside the features due to the differential passivation of the remaining layer. This deposition variation, in turn, may aid in preventing premature closing of the feature and facilitate filling of the feature in a substantially void free manner.
    Type: Application
    Filed: January 17, 2012
    Publication date: May 10, 2012
    Inventors: Anand Chandrashekar, Raashina Humayun, Michal Danek, Aaron R. Fellis, Sean Chang
  • Patent number: 8153520
    Abstract: Methods of processing partially manufactured semiconductor substrates with one or more through silicon vias to partially remove a tungsten layer formed on the field region during filling the through silicon vias are provided. In certain embodiments, the methods produce substrates with reduced bowing than the bowing present after through silicon vias filling. Substrates with reduced bowing are easier to handle and may expedite subsequent processes.
    Type: Grant
    Filed: August 3, 2009
    Date of Patent: April 10, 2012
    Assignee: Novellus Systems, Inc.
    Inventors: Anand Chandrashekar, Raashina Humayun, Michal Danek
  • Patent number: 8129270
    Abstract: Top-down methods of increasing reflectivity of tungsten films to form films having high reflectivity, low resistivity and low roughness are provided. The methods involve bulk deposition of tungsten followed by a removing a top portion of the deposited tungsten. In particular embodiments, removing a top portion of the deposited tungsten involve exposing it to a fluorine-containing plasma. The methods produce low resistivity tungsten bulk layers having lower roughness and higher reflectivity. The smooth and highly reflective tungsten layers are easier to photopattern than conventional low resistivity tungsten films. Applications include forming tungsten bit lines.
    Type: Grant
    Filed: December 10, 2008
    Date of Patent: March 6, 2012
    Assignee: Novellus Systems, Inc.
    Inventors: Anand Chandrashekar, Raashina Humayun
  • Patent number: 8124531
    Abstract: Methods and apparatuses for filling high aspect ratio features with tungsten-containing materials in a substantially void-free manner are provided. In certain embodiments, the method involves depositing an initial layer of a tungsten-containing material followed by selectively removing a portion of the initial layer to form a remaining layer, which is differentially passivated along the depth of the high-aspect ration feature. In certain embodiments, the remaining layer is more passivated near the feature opening than inside the feature. The method may proceed with depositing an additional layer of the same or other material over the remaining layer. The deposition rate during this later deposition operation is slower near the feature opening than inside the features due to the differential passivation of the remaining layer. This deposition variation, in turn, may aid in preventing premature closing of the feature and facilitate filling of the feature in a substantially void free manner.
    Type: Grant
    Filed: January 28, 2011
    Date of Patent: February 28, 2012
    Assignee: Novellus Systems, Inc.
    Inventors: Anand Chandrashekar, Raashina Humayun, Michal Danek, Aaron R. Fellis, Sean Chang
  • Publication number: 20120015518
    Abstract: Methods of forming low resistivity tungsten films with good uniformity and good adhesion to the underlying layer are provided. The methods involve forming a tungsten nucleation layer using a pulsed nucleation layer process at low temperature and then treating the deposited nucleation layer prior to depositing the bulk tungsten fill. The treatment operation lowers resistivity of the deposited tungsten film. In certain embodiments, the depositing the nucleation layer involves a boron-based chemistry in the absence of hydrogen. Also in certain embodiments, the treatment operations involve exposing the nucleation layer to alternating cycles of a reducing agent and a tungsten-containing precursor. The methods are useful for depositing films in high aspect ratio and/or narrow features. The films exhibit low resistivity at narrow line widths and excellent step coverage.
    Type: Application
    Filed: September 23, 2011
    Publication date: January 19, 2012
    Inventors: Anand Chandrashekar, Mirko Glass, Raashina Humayun, Michael Danek, Kaihan Ashtiani, Feng Chen, Lana Hiului Chan, Anil Mane
  • Publication number: 20120009785
    Abstract: Methods and apparatuses for filling high aspect ratio features with tungsten-containing materials are provided. The method involves providing a partially fabricated semiconductor substrate and depositing a tungsten-containing layer on the substrate surface to partially fill one or more high aspect ratio features. The method continues with selective removal of a portion of the deposited layer such that more material is removed near the feature opening than inside the feature. In certain embodiments, removal may be performed at mass-transport limited conditions with less etchant available inside the feature than near its opening. Etchant species are activated before being introduced into the processing chamber and/or while inside the chamber. In specific embodiments, recombination of the activated species is substantially limited and/or controlled during removal, e.g., operation is performed at less than about 250° C. and/or less than about 5 Torr.
    Type: Application
    Filed: July 9, 2010
    Publication date: January 12, 2012
    Inventors: Anand Chandrashekar, Raashina Humayun, Michal Danek, Aaron R. Fellis, Sean Chang
  • Patent number: 8058170
    Abstract: Methods of forming low resistivity tungsten films with good uniformity and good adhesion to the underlying layer are provided. The methods involve forming a tungsten nucleation layer using a pulsed nucleation layer process at low temperature and then treating the deposited nucleation layer prior to depositing the bulk tungsten fill. The treatment operation lowers resistivity of the deposited tungsten film. In certain embodiments, the depositing the nucleation layer involves a boron-based chemistry in the absence of hydrogen. Also in certain embodiments, the treatment operations involve exposing the nucleation layer to alternating cycles of a reducing agent and a tungsten-containing precursor. The methods are useful for depositing films in high aspect ratio and/or narrow features. The films exhibit low resistivity at narrow line widths and excellent step coverage.
    Type: Grant
    Filed: March 19, 2009
    Date of Patent: November 15, 2011
    Assignee: Novellus Systems, Inc.
    Inventors: Anand Chandrashekar, Mirko Glass, Raashina Humayun, Michael Danek, Kaihan Ashtiani, Feng Chen, Lana Hiului Chan, Anil Mane
  • Publication number: 20110159690
    Abstract: Methods and apparatuses for filling high aspect ratio features with tungsten-containing materials in a substantially void-free manner are provided. In certain embodiments, the method involves depositing an initial layer of a tungsten-containing material followed by selectively removing a portion of the initial layer to form a remaining layer, which is differentially passivated along the depth of the high-aspect ration feature. In certain embodiments, the remaining layer is more passivated near the feature opening than inside the feature. The method may proceed with depositing an additional layer of the same or other material over the remaining layer. The deposition rate during this later deposition operation is slower near the feature opening than inside the features due to the differential passivation of the remaining layer. This deposition variation, in turn, may aid in preventing premature closing of the feature and facilitate filling of the feature in a substantially void free manner.
    Type: Application
    Filed: January 28, 2011
    Publication date: June 30, 2011
    Inventors: Anand Chandrashekar, Raashina Humayun, Michal Danek, Aaron R. Fellis, Sean Chang
  • Publication number: 20100267235
    Abstract: Provided are methods of void-free tungsten fill of high aspect ratio features. According to various embodiments, the methods involve a reduced temperature chemical vapor deposition (CVD) process to fill the features with tungsten. In certain embodiments, the process temperature is maintained at less than about 350° C. during the chemical vapor deposition to fill the feature. The reduced-temperature CVD tungsten fill provides improved tungsten fill in high aspect ratio features, provides improved barriers to fluorine migration into underlying layers, while achieving similar thin film resistivity as standard CVD fill. Also provided are methods of depositing thin tungsten films having low-resistivity. According to various embodiments, the methods involve performing a reduced temperature low resistivity treatment on a deposited nucleation layer prior to depositing a tungsten bulk layer and/or depositing a bulk layer via a reduced temperature CVD process followed by a high temperature CVD process.
    Type: Application
    Filed: April 6, 2010
    Publication date: October 21, 2010
    Inventors: Feng Chen, Raashina Humayun, Michal Danek, Anand Chandrashekar
  • Publication number: 20100267230
    Abstract: Provided are methods of void-free tungsten fill of high aspect ratio features. According to various embodiments, the methods involve a reduced temperature chemical vapor deposition (CVD) process to fill the features with tungsten. In certain embodiments, the process temperature is maintained at less than about 350° C. during the chemical vapor deposition to fill the feature. The reduced-temperature CVD tungsten fill provides improved tungsten fill in high aspect ratio features, provides improved barriers to fluorine migration into underlying layers, while achieving similar thin film resistivity as standard CVD fill. Also provided are methods of depositing thin tungsten films having low-resistivity. According to various embodiments, the methods involve performing a reduced temperature low resistivity treatment on a deposited nucleation layer prior to depositing a tungsten bulk layer and/or depositing a bulk layer via a reduced temperature CVD process followed by a high temperature CVD process.
    Type: Application
    Filed: April 6, 2010
    Publication date: October 21, 2010
    Inventors: Anand Chandrashekar, Feng Chen, Raashina Humayun, Michal Danek
  • Publication number: 20100159694
    Abstract: Methods of forming low resistivity tungsten films with good uniformity and good adhesion to the underlying layer are provided. The methods involve forming a tungsten nucleation layer using a pulsed nucleation layer process at low temperature and then treating the deposited nucleation layer prior to depositing the bulk tungsten fill. The treatment operation lowers resistivity of the deposited tungsten film. In certain embodiments, the depositing the nucleation layer involves a boron-based chemistry in the absence of hydrogen. Also in certain embodiments, the treatment operations involve exposing the nucleation layer to alternating cycles of a reducing agent and a tungsten-containing precursor. The methods are useful for depositing films in high aspect ratio and/or narrow features. The films exhibit low resistivity at narrow line widths and excellent step coverage.
    Type: Application
    Filed: March 19, 2009
    Publication date: June 24, 2010
    Applicant: Novellus Systems Inc.
    Inventors: Anand Chandrashekar, Mirko Glass, Raashina Humayun, Michael Danek, Kaihan Ashtiani, Feng Chen, Lana Hiului Chan, Anil Mane