Patents by Inventor Kaihan A. Ashtiani
Kaihan A. Ashtiani 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).
-
Publication number: 20120040530Abstract: Novel low-resistivity tungsten film stack schemes and methods for depositing them are provided. The film stacks include a mixed tungsten/tungsten-containing compound (e.g., WC) layer as a base for deposition of tungsten nucleation and/or bulk layers. According to various embodiments, these tungsten rich layers may be used as barrier and/or adhesion layers in tungsten contact metallization and bitlines. Deposition of the tungsten-rich layers involves exposing the substrate to a halogen-free organometallic tungsten precursor. The mixed tungsten/tungsten carbide layer is a thin, low resistivity film with excellent adhesion and a good base for subsequent tungsten plug or line formation.Type: ApplicationFiled: October 18, 2011Publication date: February 16, 2012Inventors: Raashina HUMAYUN, Kaihan ASHTIANI, Karl B. LEVY
-
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
-
Patent number: 8062977Abstract: Heater elements made of high resistivity ternary and quaternary thin films containing three or more of W, C, O, N and Si are provided. The thin films have resistivities at least about 1000 ??-cm at 50 to 60 Angstroms. The ternary and quaternary films have improved stability over binary films on anneal. Methods of depositing the thin films are also provided. The methods involve depositing the film from an organometallic tungsten precursor under conditions such that a highly resistive, continuous film is formed.Type: GrantFiled: January 30, 2009Date of Patent: November 22, 2011Assignee: Novellus Systems, Inc.Inventors: Kaihan Ashtiani, Raashina Humayun, Girish Dixit, Anna Battaglia, Stefano Rassiga
-
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
-
Patent number: 8053365Abstract: Novel low-resistivity tungsten film stack schemes and methods for depositing them are provided. The film stacks include a mixed tungsten/tungsten-containing compound (e.g., WC) layer as a base for deposition of tungsten nucleation and/or bulk layers. According to various embodiments, these tungsten rich layers may be used as barrier and/or adhesion layers in tungsten contact metallization and bitlines. Deposition of the tungsten-rich layers involves exposing the substrate to a halogen-free organometallic tungsten precursor. The mixed tungsten/tungsten carbide layer is a thin, low resistivity film with excellent adhesion and a good base for subsequent tungsten plug or line formation.Type: GrantFiled: December 21, 2007Date of Patent: November 8, 2011Assignee: Novellus Systems, Inc.Inventors: Raashina Humayun, Kaihan Ashtiani, Karl B. Levy
-
Patent number: 8043972Abstract: Methods for accurate and conformal removal of atomic layers of materials make use of the self-limiting nature of adsorption of at least one reactant on the substrate surface. In certain embodiments, a first reactant is introduced to the substrate in step (a) and is adsorbed on the substrate surface until the surface is partially or fully saturated. A second reactant is then added in step (b), reacting with the adsorbed layer of the first reactant to form an etchant. The amount of an etchant, and, consequently, the amount of etched material is limited by the amount of adsorbed first reactant. By repeating steps (a) and (b), controlled atomic-scale etching of material is achieved. These methods may be used in interconnect pre-clean applications, gate dielectric processing, manufacturing of memory devices, or any other applications where removal of one or multiple atomic layers of material is desired.Type: GrantFiled: July 16, 2008Date of Patent: October 25, 2011Assignee: Novellus Systems, Inc.Inventors: Xinye Liu, Joshua Collins, Kaihan A. Ashtiani
-
Publication number: 20110223763Abstract: The present invention addresses this need by providing methods for depositing low resistivity tungsten films in small features and features having high aspect ratios. The methods involve depositing very thin tungsten nucleation layers by pulsed nucleation layer (PNL) processes and then using chemical vapor deposition (CVD) to deposit a tungsten layer to fill the feature. Depositing the tungsten nucleation layer involves exposing the substrate to alternating pulses of a boron-containing reducing agent and a tungsten-containing precursor without using any hydrogen gas, e.g., as a carrier or background gas. Using this process, a conformal tungsten nucleation layer can be deposited to a thickness as small as about 10 Angstroms. The feature may then be wholly or partially filled with tungsten by a hydrogen reduction chemical vapor deposition process. Resistivities of about 14 ??-cm for a 500 Angstrom film may be obtained.Type: ApplicationFiled: April 27, 2011Publication date: September 15, 2011Inventors: Lana Hiului Chan, Kaihan Ashtiani, Joshua Collins
-
Publication number: 20110151678Abstract: Novel gap fill schemes involving depositing both flowable oxide films and high density plasma chemical vapor deposition oxide (HDP oxide) films are provided. According to various embodiments, the flowable oxide films may be used as a sacrificial layer and/or as a material for bottom up gap fill. In certain embodiments, the top surface of the filled gap is an HDP oxide film. The resulting filled gap may be filled only with HDP oxide film or a combination of HDP oxide and flowable oxide films. The methods provide improved top hat reduction and avoid clipping of the structures defining the gaps.Type: ApplicationFiled: December 9, 2010Publication date: June 23, 2011Inventors: Kaihan Ashtiani, Michael Wood, John Drewery, Naohiro Shoda, Bart van Schravendijk, Lakshminarayana Nittala, Nerissa Draeger
-
Patent number: 7955972Abstract: The present invention addresses this need by providing methods for depositing low resistivity tungsten films in small features and features having high aspect ratios. The methods involve depositing very thin tungsten nucleation layers by pulsed nucleation layer (PNL) processes and then using chemical vapor deposition (CVD) to deposit a tungsten layer to fill the feature. Depositing the tungsten nucleation layer involves exposing the substrate to alternating pulses of a boron-containing reducing agent and a tungsten-containing precursor without using any hydrogen gas, e.g., as a carrier or background gas. Using this process, a conformal tungsten nucleation layer can be deposited to a thickness as small as about 10 Angstroms. The feature may then be wholly or partially filled with tungsten by a hydrogen reduction chemical vapor deposition process. Resistivities of about 14 ??-cm for a 500 Angstrom film may be obtained.Type: GrantFiled: February 13, 2008Date of Patent: June 7, 2011Assignee: Novellus Systems, Inc.Inventors: Lana Hiului Chan, Kaihan Ashtiani, Joshua Collins
-
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
-
Patent number: 7691749Abstract: Methods for depositing a tungsten nitride layer are described. The methods form a tungsten nitride layer using a carefully controlled deposition technique such as pulsed nucleation layer (PNL). Initially, a tungsten layer is formed on a substrate surface. The tungsten layer is then exposed to a nitriding agent to form a tungsten nitride layer. Methods of forming relatively thick layers of involve repeated cycles of contact with reducing agent, tungsten precursor and nitriding agent. In some cases, the cycle may also include contact with a dopant precursor such as phosphine or arsine.Type: GrantFiled: December 16, 2005Date of Patent: April 6, 2010Assignee: Novellus Systems, Inc.Inventors: Karl B. Levy, Junghwan Sung, Kaihan A. Ashtiani, James A. Fair, Joshua Collins, Juwen Gao
-
Publication number: 20090163025Abstract: Novel low-resistivity tungsten film stack schemes and methods for depositing them are provided. The film stacks include a mixed tungsten/tungsten-containing compound (e.g., WC) layer as a base for deposition of tungsten nucleation and/or bulk layers. According to various embodiments, these tungsten rich layers may be used as barrier and/or adhesion layers in tungsten contact metallization and bitlines. Deposition of the tungsten-rich layers involves exposing the substrate to a halogen-free organometallic tungsten precursor. The mixed tungsten/tungsten carbide layer is a thin, low resistivity film with excellent adhesion and a good base for subsequent tungsten plug or line formation.Type: ApplicationFiled: December 21, 2007Publication date: June 25, 2009Applicant: NOVELLUS SYSTEMS, INC.Inventors: Raashina Humayun, Kaihan Ashtiani, Karl B. Levy
-
Publication number: 20080254623Abstract: The present invention addresses this need by providing methods for depositing low resistivity tungsten films in small features and features having high aspect ratios. The methods involve depositing very thin tungsten nucleation layers by pulsed nucleation layer (PNL) processes and then using chemical vapor deposition (CVD) to deposit a tungsten layer to fill the feature. Depositing the tungsten nucleation layer involves exposing the substrate to alternating pulses of a boron-containing reducing agent and a tungsten-containing precursor without using any hydrogen gas, e.g., as a carrier or background gas. Using this process, a conformal tungsten nucleation layer can be deposited to a thickness as small as about 10 Angstroms. The feature may then be wholly or partially filled with tungsten by a hydrogen reduction chemical vapor deposition process. Resistivities of about 14 ??-cm for a 500 Angstrom film may be obtained.Type: ApplicationFiled: February 13, 2008Publication date: October 16, 2008Applicant: NOVELLUS SYSTEMS, INC.Inventors: Lana Hiului Chan, Kaihan Ashtiani, Joshua Collins
-
Patent number: 7416989Abstract: Methods for accurate and conformal removal of atomic layers of materials make use of the self-limiting nature of adsorption of at least one reactant on the substrate surface. In certain embodiments, a first reactant is introduced to the substrate in step (a) and is adsorbed on the substrate surface until the surface is partially or fully saturated. A second reactant is then added in step (b), reacting with the adsorbed layer of the first reactant to form an etchant. The amount of an etchant, and, consequently, the amount of etched material is limited by the amount of adsorbed first reactant. By repeating steps (a) and (b), controlled atomic-scale etching of material is achieved. These methods may be used in interconnect pre-clean applications, gate dielectric processing, manufacturing of memory devices, or any other applications where removal of one or multiple atomic layers of material is desired.Type: GrantFiled: June 30, 2006Date of Patent: August 26, 2008Assignee: Novellus Systems, Inc.Inventors: Xinye Liu, Joshua Collins, Kaihan A. Ashtiani
-
Patent number: 7262125Abstract: Methods and apparatus for preparing a low-resistivity tungsten film on a substrate are provided. Methods involve the formation of a tungsten nucleation layer on a substrate using pulsed nucleation layer (PNL) techniques and depositing a bulk tungsten layer thereon. Methods for forming the tungsten nucleation layer involve the use of a boron-containing species, a tungsten-containing precursor, and optionally, a silane. The methods described are particularly useful for applications where thin, low resistivity films are desired, such as interconnect applications.Type: GrantFiled: March 31, 2004Date of Patent: August 28, 2007Assignee: Novellus Systems, Inc.Inventors: Panya Wongsenakhum, Aaron R. Fellis, Kaihan A. Ashtiani, Karl B. Levy, Juwen Gao, Joshua Collins, Junghwan Sung, Lana Hiului Chan
-
Patent number: 7141494Abstract: A tungsten nucleation film is formed on a surface of a semiconductor substrate by alternatively providing to that surface, reducing gases and tungsten-containing gases. Each cycle of the method provides for one or more monolayers of the tungsten film. The film is conformal and has improved step coverage, even for a high aspect ratio contact hole.Type: GrantFiled: August 26, 2003Date of Patent: November 28, 2006Assignee: Novellus Systems, Inc.Inventors: Sang-Hyeob Lee, Karl B. Levy, Aaron R. Fellis, Panya Wongsenakhum, Juwen Gao, Joshua Collins, Kaihan A. Ashtiani, Junghwan Sung, Lana Hiului Chan
-
Publication number: 20060094238Abstract: Methods for depositing a tungsten nitride layer are described. The methods form a tungsten nitride layer using a carefully controlled deposition technique such as pulsed nucleation layer (PNL). Initially, a tungsten layer is formed on a substrate surface. The tungsten layer is then exposed to a nitriding agent to form a tungsten nitride layer. Methods of forming relatively thick layers of involve repeated cycles of contact with reducing agent, tungsten precursor and nitriding agent. In some cases, the cycle may also include contact with a dopant precursor such as phosphine or arsine.Type: ApplicationFiled: December 16, 2005Publication date: May 4, 2006Inventors: Karl Levy, Junghwan Sung, Kaihan Ashtiani, James Fair, Joshua Collins, Juwen Gao
-
Patent number: 7005372Abstract: Methods for depositing a tungsten nitride layer are described. The methods form a tungsten nitride layer using a carefully controlled deposition technique such as pulsed nucleation layer (PNL). Initially, a tungsten layer is formed on a substrate surface. The tungsten layer is then exposed to a nitriding agent to form a tungsten nitride layer. Methods of forming relatively thick layers of involve repeated cycles of contact with reducing agent, tungsten precursor and nitriding agent. In some cases, the cycle may also include contact with a dopant precursor such as phosphine or arsine.Type: GrantFiled: October 20, 2003Date of Patent: February 28, 2006Assignee: Novellus Systems, Inc.Inventors: Karl B. Levy, Junghwan Sung, Kaihan A. Ashtiani, James A. Fair, Joshua Collins, Juwen Gao
-
Patent number: 6905959Abstract: A method of depositing thin films comprising tantalum, tantalum nitride, and copper for barrier films and seed layers within high aspect ratio openings used for copper interconnects. The barrier films and seed layers are deposited at extremely low temperature conditions wherein the wafer stage temperature of the sputter source is chilled to about ?70° C. to about 0° C. Most preferably, the present invention is practiced using a hollow cathode magnetron. The resulting tantalum and/or tantalum nitride barrier films and copper seed layers are superior in surface smoothness, grain size and uniformity such that subsequent filling of the high aspect ratio opening is substantially void-free.Type: GrantFiled: December 31, 2002Date of Patent: June 14, 2005Assignee: Novellus Systems, Inc.Inventors: Kaihan A. Ashtiani, Maximilian A. Biberger, Erich R. Klawuhn, Kwok Fai Lai, Karl B. Levy, J. Patrick Rymer
-
Publication number: 20050031786Abstract: A tungsten nucleation film is formed on a surface of a semiconductor substrate by alternatively providing to that surface, reducing gases and tungsten-containing gases. Each cycle of the method provides for one or more monolayers of the tungsten film. The film is conformal and has improved step coverage, even for a high aspect ratio contact hole.Type: ApplicationFiled: August 26, 2003Publication date: February 10, 2005Inventors: Sang-Hyeob Lee, Karl Levy, Aaron Fellis, Panya Wongsenakhum, Juwen Gao, Joshua Collins, Kaihan Ashtiani, Junghwan Sung, Lana Chan