Abstract: Capping protective self aligned buffer (PSAB) layers are layers of material that are selectively formed at the surface of metal layers in a partially fabricated semiconductor device. Encapsulating PSAB layers are formed not only at the surface of the metal layers, but also within the unexposed portions of the metal lines. Encapsulating PSAB layer, for example, can surround the metal line with the PSAB material, thereby protecting interfaces between the metal line and diffusion barriers. Encapsulating PSAB layers can be formed by treating the exposed surfaces of metal lines with GeH4. Capping PSAB layers can be formed by treating the exposed surfaces of metal lines with SiH4. Interconnects having both a silicon-containing capping PSAB layer and a germanium-containing encapsulating PSAB layer provide good performance in terms of adhesion, resistance shift, and electromigration characteristics.
Abstract: Improved methods of depositing copper seed layers in copper interconnect structure fabrication processes are provided. Also provided are the resulting structures, which have improved electromigration performance and reduced line resistance. According to various embodiments, the methods involve depositing a copper seed bilayer on a barrier layer in a recessed feature on a partially fabricated semiconductor substrate. The bilayer has a copper alloy seed layer and a pure copper seed layer, with the pure copper seed layer is deposited on the copper alloy seed layer. The copper seed bilayers have reduced line resistance increase and better electromigration performance than conventional doped copper seed layers. Precise line resistance control is achieved by tuning the bilayer thickness to meet the desired electromigration performance.
Type:
Grant
Filed:
May 16, 2008
Date of Patent:
September 13, 2011
Assignee:
Novellus Systems, Inc.
Inventors:
Hui-Jung Wu, Daniel R. Juliano, Wen Wu, Girish Dixit
Abstract: Apparatuses and methods for diverting a flow of a liquid precursor during flow stabilization and plasma stabilization stages during PECVD processes are effective at eliminating particle defects in PECVD films deposited using a liquid precursor.
Type:
Grant
Filed:
December 16, 2008
Date of Patent:
September 13, 2011
Assignee:
Novellus Systems, Inc.
Inventors:
Arul N. Dhas, Ming Li, Joseph Bradley Laird
Abstract: A shielding system for a physical vapor deposition (PVD) chamber is disclosed. The PVD chamber includes a pedestal supporting a substrate. The shielding system includes a first annular portion and a second annular portion of a pedestal shield. The first annular portion is attached the pedestal at a first location. The first annular portion is located at or below a plane including the substrate. The second annular portion is attached to the pedestal at a second location that is below the first location. The first annular portion is spaced a predetermined distance from the second annular portion and is electrically isolated from the second annular portion.
Abstract: A nitrogen-free anti-reflective layer for use in semiconductor photolithography is fabricated in a chemical vapor deposition process, optionally plasma-enhanced, using a gaseous mixture of carbon, silicon, and oxygen sources. By varying the process parameters, a substantially hermetic layer with acceptable values of the refractive index n and extinction coefficient k can be obtained. The nitrogen-free moisture barrier anti-reflective layer produced by this technique improves plasma etch of features such as vias in subsequent processing steps.
Type:
Grant
Filed:
November 20, 2009
Date of Patent:
August 23, 2011
Assignee:
Novellus Systems, Inc.
Inventors:
Ming Li, Bart Van Schravendijk, Tom Mountsier, Chiu Chi, Kevin Ilcisin, Julian Hsieh
Abstract: Transistor architectures and fabrication processes generate channel strain without adversely impacting the efficiency of the transistor fabrication process while preserving the material quality and enhancing the performance of the resulting transistor. Transistor strain is generated is PMOS devices using a highly compressive post-salicide boron doped carbon capping layer applied as a blanket over on at least the source and drain regions. The stress from this capping layer is uniaxially transferred to the PMOS channel through the source-drain regions to create compressive strain in PMOS channel.
Type:
Grant
Filed:
June 6, 2008
Date of Patent:
August 16, 2011
Assignee:
Novellus Systems, Inc.
Inventors:
Qingguo Wu, James S. Sims, Mandyam Sriram, Seshasayee Varadarajan, Akhil Singhal
Abstract: Functionalized nanoparticles are deposited on metal lines inlaid in dielectric to form a metal cap layer that reduces electromigration in the metal line. The functionalized nanoparticles are deposited onto activated metal surfaces, then sintered and annealed to remove the functional agents leaving behind a continuous capping layer. The resulting cap layer is about 1 to 10 nm thick with 30-100% atomic of the nanoparticle material. Various semiconductor processing tools may be adapted for this deposition process without adding footprint in the semiconductor fabrication plant.
Abstract: An apparatus and method for depositing film on a substrate includes a plurality of conduits that allow by-product and reactant gases to flow past the edge of a substrate. The apparatus and process of the present invention has several advantages for enhanced chamber performance, particularly for micro-volume chambers using pulsed deposition layer processes.
Abstract: Embodiments of a closed-contact electroplating cup are disclosed. One embodiment comprises a cup bottom comprising an opening, and a seal disposed on the cup bottom around the opening. The seal comprises a wafer-contacting peak located substantially at an inner edge of the seal. The embodiment also comprises an electrical contact structure disposed over a portion of the seal, wherein the electrical contact structure comprises an outer ring and a plurality of contacts extending inwardly from the outer ring, and wherein each contact has a generally flat wafer-contacting surface. The embodiment further comprises a wafer-centering mechanism configured to center a wafer in the cup.
Type:
Grant
Filed:
October 30, 2007
Date of Patent:
July 26, 2011
Assignee:
Novellus Systems, Inc.
Inventors:
Robert Rash, Shantinath Ghongadi, Kousik Ganesan, Zhian He, Tariq Majid, Jeff Hawkins, Seshasayee Varadarajan, Bryan Buckalew
Abstract: The present invention addresses this need by providing a method for forming transparent PECVD deposited ashable hardmasks (AHMs) that have high plasma etch selectivity to underlying layers. Methods of the invention involve depositing the AHM using dilute hydrocarbon precursor gas flows and/or low process temperatures. The AHMs produced are transparent (having absorption coefficients of less than 0.1 in certain embodiments). The AHMs also have the property of high selectivity of the hard mask film to the underlying layers for successful integration of the film, and are suitable for use with 193 nm generation and below lithography schemes wherein high selectivity of the hard mask to the underlying layers is required. The lower temperature process also allows reduction of the overall thermal budget for a wafer.
Type:
Grant
Filed:
June 8, 2006
Date of Patent:
July 19, 2011
Assignee:
Novellus Systems, Inc.
Inventors:
Pramod Subramonium, Zhiyuan Fang, Jon Henri
Abstract: Methods of filling high aspect ratio, narrow width (e.g., sub-50 nm) gaps on a substrate are provided. The methods provide gap fill with little or no incidence of voids, seams or weak spots. According to various embodiments, the methods depositing dielectric material in the gaps to partially fill the gaps, then performing multi-step atomic layer removal process to selectively etch unwanted material deposited on the sidewalls of the gaps. The multi-step atomic layer removal process involves a performing one or more initial atomic layer removal operations to remove unwanted material deposited at the top of the gap, followed by one or more subsequent atomic layer removal operations to remove unwanted material deposited on the sidewalls of the gap. Each atomic layer removal operation involves selectively chemically reacting a portion of the fill material with one or more reactants to form a solid reaction product, which is then removed.
Type:
Grant
Filed:
December 22, 2008
Date of Patent:
July 19, 2011
Assignee:
Novellus Systems, Inc.
Inventors:
Bart van Schravendijk, Harald te Nijenhuis
Abstract: The present invention provides PECVD methods for forming stable and hermetic ashable hard masks (AHMs). The methods involve depositing AHMs using dilute hydrocarbon precursor gas flows and/or high LFRF/HFRF ratios. In certain embodiments, the AHMs are transparent and have high etch selectivities. Single and dual layer hermetic AHM stacks are also provided. According to various embodiments, the dual layer stack includes an underlying AHM layer having tunable optical properties and a hermetic cap layer.
Type:
Grant
Filed:
February 22, 2007
Date of Patent:
July 19, 2011
Assignee:
Novellus Systems, Inc.
Inventors:
Pramod Subramonium, Yongsik Yu, Zhiyuan Fang, Jon Henri
Abstract: Methods for removing silicon nitride and elemental silicon during contact preclean process involve converting these materials to materials that are more readily etched by fluoride-based etching methods, and subsequently removing the converted materials by a fluoride-based etch. Specifically, silicon nitride and elemental silicon may be treated with an oxidizing agent, e.g., with an oxygen-containing gas in a plasma, or with O2 or O3 in the absence of plasma to produce a material that is more rich in Si—O bonds and is more easily etched with a fluoride-based etch. Alternatively, silicon nitride or elemental silicon may be doped with a number of doping elements, e.g., hydrogen, to form materials which are more easily etched by fluoride based etches. The methods are particularly useful for pre-cleaning contact vias residing in a layer of silicon oxide based material because they minimize the unwanted increase of critical dimension of contact vias.
Abstract: An etching process for selectively etching exposed metal surfaces of a substrate and forming a conductive capping layer over the metal surfaces is described. In some embodiments, the etching process involves oxidation of the exposed metal to form a metal oxide that is subsequently removed from the surface of the substrate. The exposed metal may be oxidized by using solutions containing oxidizing agents such as peroxides or by using oxidizing gases such as those containing oxygen or ozone. The metal oxide produced is then removed using suitable metal oxide etching agents such as glycine. The oxidation and etching may occur in the same solution. In other embodiments, the exposed metal is directly etched without forming a metal oxide. Suitable direct metal etching agents include any number of acidic solutions. The process allows for controlled oxidation and/or etching with reduced pitting.
Type:
Grant
Filed:
July 30, 2007
Date of Patent:
July 5, 2011
Assignee:
Novellus Systems, Inc.
Inventors:
Steven T. Mayer, Daniel A. Koos, Eric Webb
Abstract: Porous dielectric layers are produced by introducing pores in pre-formed composite dielectric layers. The pores may be produced after the barrier material, the metal or other conductive material is deposited to form a metallization layer. In this manner, the conductive material is provided with a relatively smooth continuous surface on which to deposit.
Type:
Grant
Filed:
October 27, 2009
Date of Patent:
July 5, 2011
Assignee:
Novellus Systems, Inc.
Inventors:
Willibrordus Gerardus Maria van den Hoek, Nerissa S. Draeger, Raashina Humayun, Richard S. Hill, Jianing Sun, Gary William Ray
Abstract: Copper diffusion barrier films having low dielectric constants are suitable for a variety of copper/inter-metal dielectric integration schemes. Copper diffusion barrier films in accordance with the invention are composed of one or more layers of silicon carbide, at least one of the silicon carbide layers having a composition of at least 40% carbon (C), for example, between about 45 and 60% carbon (C). The films' high carbon-content layer will have a composition wherein the ratio of C to Si is greater than 2:1; or >3:1; or >4:1; or >5.1. The high carbon-content copper diffusion barrier films have a reduced effective k relative to conventional barrier materials.
Type:
Grant
Filed:
July 2, 2009
Date of Patent:
June 28, 2011
Assignee:
Novellus Systems, Inc.
Inventors:
Yongsik Yu, Karen Billington, Xingyuan Tang, Haiying Fu, Michael Carris, William Crew
Abstract: A substantially uniform layer of a metal is electroplated onto a work piece having a seed layer thereon. This is accomplished by employing a “high resistance ionic current source,” which solves the terminal problem by placing a highly resistive membrane (e.g., a microporous ceramic or fretted glass element) in close proximity to the wafer, thereby swamping the system's resistance. The membrane thereby approximates a constant current source. By keeping the wafer close to the membrane surface, the ionic resistance from the top of the membrane to the surface is much less than the ionic path resistance to the wafer edge, substantially compensating for the sheet resistance in the thin metal film and directing additional current over the center and middle of the wafer.
Abstract: A two-step semiconductor electroplating process deposits copper onto wafers coated with a semi-noble metal in manner that is uniform across the wafer and free of voids after a post electrofill anneal. A seed-layer plating bath nucleates copper uniformly and conformably at a high density in a very thin film using a unique pulsed waveform. The wafer is then annealed before a second bath fills the features. The seed-layer anneal improves adhesion and stability of the semi-noble to copper interface, and the resulting copper interconnect stays void-free after a post electrofill anneal.
Type:
Grant
Filed:
March 6, 2008
Date of Patent:
June 21, 2011
Assignee:
Novellus Systems, Inc.
Inventors:
Thomas Ponnuswamy, John Sukamto, Jonathan Reid, Steve Mayer
Abstract: Recessed features on a Damascene substrate are filled with metal using plasma PVD. Recessed features having widths of less than about 300 nm, e.g., between about 30-300 nm can be filled with metals (e.g., copper and aluminum), without forming voids. In one approach, the deposition is performed by exposing the substrate to a high-density plasma characterized by high fractional ionization of metal. Under these conditions, the metal is deposited within the recess, without forming large overhang at the opening of the recess. In some embodiments, the metal is deposited within the recess, while diffusion barrier material is simultaneously etched from the field region. In a second approach, recessed features are filled by performing a plurality of profiling cycles, wherein each cycle includes a net etching and a net depositing operation. Etching and depositing parameters are adjusted such that the recessed features are filled without forming overhangs and voids.
Type:
Grant
Filed:
February 29, 2008
Date of Patent:
June 21, 2011
Assignee:
Novellus Systems, Inc.
Inventors:
Roey Shaviv, Alexander Dulkin, Daniel Juliano, Ronald Kinder