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).
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Patent number: 8623733Abstract: 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: GrantFiled: April 6, 2010Date of Patent: January 7, 2014Assignee: Novellus Systems, Inc.Inventors: Feng Chen, Raashina Humayun, Michal Danek, Anand Chandrashekar
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Publication number: 20130330926Abstract: 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: ApplicationFiled: May 6, 2013Publication date: December 12, 2013Inventors: Anand Chandrashekar, Raashina Humayun, Michal Danek, Aaron R. Fellis, Sean Chang
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Publication number: 20130302980Abstract: 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: ApplicationFiled: March 27, 2013Publication date: November 14, 2013Inventors: Anand Chandrashekar, Esther Jeng, Raashina Humayun, Michal Danek, Juwen Gao, Deqi Wang
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Patent number: 8501620Abstract: 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: GrantFiled: March 5, 2012Date of Patent: August 6, 2013Assignee: Novellus Systems, Inc.Inventors: Anand Chandrashekar, Raashina Humayun
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Publication number: 20130171822Abstract: 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: ApplicationFiled: February 22, 2013Publication date: July 4, 2013Inventors: Anand Chandrashekar, Esther Jeng, Raashina Humayun, Michal Danek, Juwen Gao, Deqi Wang
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Patent number: 8435894Abstract: 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: GrantFiled: January 17, 2012Date of Patent: May 7, 2013Assignee: Novellus Systems, Inc.Inventors: Anand Chandrashekar, Raashina Humayun, Michal Danek, Aaron R. Fellis, Sean Chang
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Patent number: 8409987Abstract: 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: GrantFiled: September 23, 2011Date of Patent: April 2, 2013Assignee: Novellus Systems, Inc.Inventors: Anand Chandrashekar, Mirko Glass, Raashina Humayun, Michal Danek, Kaihan Ashtiani, Feng Chen, Lana Hiului Chan, Anil Mane
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Publication number: 20130005140Abstract: 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: ApplicationFiled: June 28, 2012Publication date: January 3, 2013Applicant: Novellus Systems, Inc.Inventors: Esther Jeng, Anand Chandrashekar, Raashina Humayun, Michal Danek, Ronald Powell
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Publication number: 20120164832Abstract: 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: ApplicationFiled: March 5, 2012Publication date: June 28, 2012Inventors: Anand CHANDRASHEKAR, Raashina HUMAYUN
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Publication number: 20120115329Abstract: 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: ApplicationFiled: January 17, 2012Publication date: May 10, 2012Inventors: Anand Chandrashekar, Raashina Humayun, Michal Danek, Aaron R. Fellis, Sean Chang
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Patent number: 8153520Abstract: 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: GrantFiled: August 3, 2009Date of Patent: April 10, 2012Assignee: Novellus Systems, Inc.Inventors: Anand Chandrashekar, Raashina Humayun, Michal Danek
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Patent number: 8129270Abstract: 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: GrantFiled: December 10, 2008Date of Patent: March 6, 2012Assignee: Novellus Systems, Inc.Inventors: Anand Chandrashekar, Raashina Humayun
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Patent number: 8124531Abstract: 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: GrantFiled: January 28, 2011Date of Patent: February 28, 2012Assignee: Novellus Systems, Inc.Inventors: Anand Chandrashekar, Raashina Humayun, Michal Danek, Aaron R. Fellis, Sean Chang
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Publication number: 20120015518Abstract: 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: ApplicationFiled: September 23, 2011Publication date: January 19, 2012Inventors: Anand Chandrashekar, Mirko Glass, Raashina Humayun, Michael Danek, Kaihan Ashtiani, Feng Chen, Lana Hiului Chan, Anil Mane
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Publication number: 20120009785Abstract: 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: ApplicationFiled: July 9, 2010Publication date: January 12, 2012Inventors: Anand Chandrashekar, Raashina Humayun, Michal Danek, Aaron R. Fellis, Sean Chang
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Patent number: 8058170Abstract: 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: GrantFiled: March 19, 2009Date of Patent: November 15, 2011Assignee: Novellus Systems, Inc.Inventors: Anand Chandrashekar, Mirko Glass, Raashina Humayun, Michael Danek, Kaihan Ashtiani, Feng Chen, Lana Hiului Chan, Anil Mane
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Publication number: 20110159690Abstract: 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: ApplicationFiled: January 28, 2011Publication date: June 30, 2011Inventors: Anand Chandrashekar, Raashina Humayun, Michal Danek, Aaron R. Fellis, Sean Chang
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Publication number: 20100267235Abstract: 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: ApplicationFiled: April 6, 2010Publication date: October 21, 2010Inventors: Feng Chen, Raashina Humayun, Michal Danek, Anand Chandrashekar
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Publication number: 20100267230Abstract: 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: ApplicationFiled: April 6, 2010Publication date: October 21, 2010Inventors: Anand Chandrashekar, Feng Chen, Raashina Humayun, Michal Danek
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Publication number: 20100159694Abstract: 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: ApplicationFiled: March 19, 2009Publication date: June 24, 2010Applicant: Novellus Systems Inc.Inventors: Anand Chandrashekar, Mirko Glass, Raashina Humayun, Michael Danek, Kaihan Ashtiani, Feng Chen, Lana Hiului Chan, Anil Mane