Patents Represented by Attorney Todd M. C. Li
  • Patent number: 6984564
    Abstract: An SRAM in a CMOS integrated circuit is subjected to stress on the channels of its transistors; compressive stress on the pull-up and pass gate transistors and tensile stress on the pull-down transistors in a version designed to improve stability; and compressive stress on the pull-up transistors and tensile stress on the pull-down and pass gate transistors in a version designed to reduce the cell size and increase speed of operation.
    Type: Grant
    Filed: June 24, 2004
    Date of Patent: January 10, 2006
    Assignee: International Business Machines Corporation
    Inventors: Shih-Fen Huang, Clement Wann, Haining S. Yang
  • Patent number: 6964032
    Abstract: A method of designing a mask for imaging an integrated circuit (IC) design layout is provided to efficiently configure subresolution assist features (SRAFs) corresponding to an optimally configured annular illumination source of a lithographic projection system. A critical pitch is identified for the IC design, and optimal inner and outer radial coordinates of an annular illumination source are determined so that the resulting image projected through the mask will be optimized for the full range of pitches in the design layout. A relationship is provided for determining an optimal inner radius and outer radius for the annular illumination source. The number and placement of SRAFs are added to the mask design so that the resulting range of pitches substantially correspond to the critical pitch. The method of configuring SRAFs so that the image will have optimal characteristics, such as good contrast and good depth of focus, is fast.
    Type: Grant
    Filed: February 28, 2003
    Date of Patent: November 8, 2005
    Assignee: International Business Machines Corporation
    Inventors: Lars W. Liebmann, Allen H. Gabor, Ronald L. Gordon, Carlos A. Fonseca, Martin Burkhardt
  • Patent number: 6960772
    Abstract: A carrier for the masks used in Electron Projection Lithography, or other workpieces used in nanotechnology fields, comprises a rectangular frame having a set of four electrostatic chucks in the top surface for holding the mask above a central aperture that has an electron absorber on the bottom for suppressing backscattering; the frame being supported by a bottom carrier that grips the frame with a set of flexures flexible in the z-direction, stiff in an azimuthal direction and flexible in a radial direction.
    Type: Grant
    Filed: June 9, 2004
    Date of Patent: November 1, 2005
    Assignee: International Business Machines Corporation
    Inventors: Gary J. Johnson, David J. Pinckney
  • Patent number: 6960532
    Abstract: Damage to the rim of a semiconductor wafer caused by etching processes is reduced by forming a rim of carbonized photoresist around the outer edge of the wafer, using a wafer edge tool to carbonize the outer rim of a positive tone photoresist.
    Type: Grant
    Filed: February 28, 2003
    Date of Patent: November 1, 2005
    Assignees: International Business Machines Corporation, Infineon Technologies AG
    Inventors: Linda A. Chen, Wai-Kin Li
  • Patent number: 6939664
    Abstract: Inventive silsesquioxane polymers are provided, and resist compositions that contain such silsesquioxane polymers are provided in which at least a portion of the silsesquioxane polymer contains fluorinated moieties, and at least a portion of the silisesquioxane polymer contains pendant solubility inhibiting acid-labile moieties that have low activation energy for acid-catalyzed cleaving, and the presence of high optical density moieties are minimized or avoided. The inventive polymer also contains pendant polar moieties that promote alkaline solubility of the resist in aqueous alkaline solutions. The inventive polymers are particularly useful in positive resist compositions. The invention encompasses methods of using such resist compositions in forming a patterned structure on a substrate, and particularly multilayer (e.g. bilayer) photolithographic methods, which methods are capable of producing high resolution images at wavelengths such as 193 nm and 157 nm.
    Type: Grant
    Filed: October 24, 2003
    Date of Patent: September 6, 2005
    Assignee: International Business Machines Corporation
    Inventors: Wu-Song Huang, Robert D. Allen, Marie Angelopoulos, Ranee W. Kwong, Ratnam Sooriyakumaran
  • Patent number: 6927172
    Abstract: Damage to the rim of a semiconductor wafer caused by etching processes is reduced by forming a rim of photoresist or other material around the outer edge of the wafer that has a thickness such that images projected on the rim are sufficiently out of focus that they do not develop, so that etching takes place only in the interior.
    Type: Grant
    Filed: February 24, 2003
    Date of Patent: August 9, 2005
    Assignees: International Business Machines Corporation, Infineon Technologies AG
    Inventors: Wolfgang Bergner, Linda A. Chen, Stephan Kudelka, Franz X. Zach
  • Patent number: 6927005
    Abstract: A method is described for designing an alternating phase shifted mask (altPSM) by optimally selecting the width of phase shapes. The selection of optimal phase shape widths is achieved by providing a lithography metric that describes the relationship between phase shape width and the target image dimension such that the metric, such as process window or across chip linewidth variation (ACLV), is optimized. In a preferred embodiment, ACLV is computed by Monte Carlo simulation by providing a set of error distributions for lithographic parameters such as focus, dose, lens aberrations, and the like. Alternatively, a lookup table of optimal phase widths associated with target image dimensions may be provided. The resulting altPSM is characterized by phase shapes having widths that vary according to the widths of the target image dimensions.
    Type: Grant
    Filed: March 16, 2004
    Date of Patent: August 9, 2005
    Assignee: International Business Machines Corporation
    Inventors: Lars W. Liebmann, Carlos A. Fonseca, Ioana Graur, Mark A. Lavin
  • Patent number: 6901576
    Abstract: A method is provided for designing an altPSM mask including a substrate. The method includes the following steps. Provide a circuit layout. Identify critical elements of the circuit layout. Provide a cutoff layout dimension. Identify critical segments of the circuit layout which are critical elements with a sub-cutoff dimension less than the cutoff dimension. Create basic phase shapes associated with the critical segments. Remove layout violations from the phase shapes. Determine whether the widths of phase shapes associated with a critical segment have unequal narrower and wider widths. If YES, then widen each narrower phase shape to match the width of wider phase shape associated with the critical segment and repeat the steps starting with removal of layout violations until the test answer is NO. When the test answer is NO, provide a layout pattern to an output.
    Type: Grant
    Filed: November 20, 2002
    Date of Patent: May 31, 2005
    Assignee: International Business Machines Corporation
    Inventors: Lars W. Liebmann, Carlos A. Fonseca, Ioana Graur
  • Patent number: 6881635
    Abstract: A planar NFET on a strained silicon layer supported by a SiGe layer achieves reduced external resistance by removing SiGe material outside the transistor body and below the strained silicon layer and replacing the removed material with epitaxial silicon, thereby providing lower resistance for the transistor electrodes and permitting better control over Arsenic diffusion.
    Type: Grant
    Filed: March 23, 2004
    Date of Patent: April 19, 2005
    Assignee: International Business Machines Corporation
    Inventors: Dureseti Chidambarrao, Effendi Leobandung, Anda C. Mocuta, Haining S. Yang, Huilong Zhu
  • Patent number: 6858530
    Abstract: A method and structure for the electrical characterization of a semiconductor device comprising, first, forming a hole having a diameter less than 0.15 ?m, wherein the hole is created using focused ion beam (FIB) etching, and through at least a protective cap layer formed over the device. The FIB etching occurs in an electron mode using a beam current less than 35 ?A with an aperture size less than 50 ?m, and at an acceleration voltage of about 50 kV. Second, the surface of the hole is coated with a metal, preferably using chemical vapor deposition (CVD) and preferably using a FIB device. Third, a metal pad is deposited, preferably by FIB CVD, over the hole. Fourth, the pad is probed to determine characteristics and/or detect defects of the electrical device. The present invention allows for electrical characterization without causing damage to the device or its features.
    Type: Grant
    Filed: June 30, 2003
    Date of Patent: February 22, 2005
    Assignee: International Business Machines Corporation
    Inventors: Terence Kane, Lawrence S. Fischer, Steven B. Herschbein, Ying Hong, Michael P. Tenney
  • Patent number: 6842237
    Abstract: A method is described for determining lens aberrations using a test reticle and a standard metrology tool. The method provides test patterns, preferably in the form of standard overlay metrology test patterns, that include blazed gratings having orientation and pitch selected to sample desired portions of the lens pupil. The method measures relative shifts in the imaged test patterns using standard metrology tools to provide both magnitude and sign of the aberrations. The metrology tools need not be modified if standard test patterns are used, but can be adapted to obtain additional information. The test reticles may be formed with multiple test patterns having a range of orientations and pitch in order to compute any desired order of lens aberration. Alternatively, single test patterns may be used to determine both the magnitude and sign of lower order lens aberrations, such as defocus or coma.
    Type: Grant
    Filed: December 28, 2001
    Date of Patent: January 11, 2005
    Assignee: International Business Machines Corporation
    Inventors: Christopher P. Ausschnitt, Timothy A. Brunner, Joseph P. Kirk, Nakgeuon Seong
  • Patent number: 6832364
    Abstract: A method and computer system is described for designing a conflict-free altPSM layout by first constructing a planar interlock graph without predefining phase shift shapes. Feature nodes of the graph represent critical elements, while connection nodes of the graph represent phase shape interactions. A pattern analysis of the interlock graph is performed to identify layout violations. Solutions for resolving layout conflicts are applied to the layout resulting in at least one conflict-free altPSM layout. Phase shapes are then applied to the conflict-free altPSM layout. Selection of an optimal solution can be made based on cost analysis.
    Type: Grant
    Filed: October 3, 2002
    Date of Patent: December 14, 2004
    Assignee: International Business Machines Corporation
    Inventors: Fook-Luen Heng, Lars W. Liebmann
  • Patent number: 6824932
    Abstract: A method and apparatus for making phase shift masks are provided wherein an anti-reflective coating used on an opaque pattern layer of the mask fully covers the opaque pattern layer and has not been etched in the etching process to form the phase shift mask. A two-exposure method to form the phase shift mask is used wherein a photoresist having a defined dose-to-clear level is coated on the surface of the mask and the lower surface of the mask is exposed to a blanket exposure in an energy amount less than the dose-to-clear level. The open areas of the upper surface of the mask to be etched are exposed to an energy dose in an amount less than the dose-to-clear level, with the sum of the amounts of the lower surface energy and upper surface energy being at least the dose-to-clear level. The method and apparatus minimizes and/or avoids etching of the anti-reflective coating.
    Type: Grant
    Filed: June 5, 2002
    Date of Patent: November 30, 2004
    Assignee: International Business Machines Corporation
    Inventors: Scott J. Bukofsky, Carlos A. Fonseca, Michael S. Hibbs, Lars W. Liebmann
  • Patent number: 6821864
    Abstract: A method of forming at least one deep trench structure having an increased trench depth is provided. The method includes providing at least one deep trench having sidewalls that extend to a common bottom wall in a surface of a substrate. Each deep trench has initial dimensions that are wider than targeted dimensions for the deep trenches. To reduce the initial dimensions to that of the targeted dimensions, an epitaxial silicon film is formed selectively or non-selectively on at least some portions of the sidewalls using a low-temperature ultra-high vacuum epitaxial silicon growth tehnique.
    Type: Grant
    Filed: March 7, 2002
    Date of Patent: November 23, 2004
    Assignee: International Business Machines Corporation
    Inventors: Kevin K. Chan, Subhash B. Kulkarni, Gangadhara S. Mathad, Rajiv M. Ranade
  • Patent number: 6819598
    Abstract: A memory module is described having a memory array storing data, an ID information output circuit for outputting ID information for identifying memory modules, and output switching means for selectively switching between output from the memory array and output from the ID information output circuit, and output from the ID information output circuit will be selected instead of output from the memory array until the memory module is initially written after the power supply to the memory module has been started. This enables a memory module to be identified without having to add parts to a computer system unit or providing a ROM storing a specification or the like to the memory module.
    Type: Grant
    Filed: October 24, 2003
    Date of Patent: November 16, 2004
    Assignee: International Business Machines Corporation
    Inventors: Satoshi Yamazaki, Tetsu Kubota, Norio Fujita
  • Patent number: 6819566
    Abstract: In a microelectronic chip package for which grounding and thermal dissipation is desired, a cover is provided having an opening which is aligned with a contact on the substrate connected to ground potential. The cover is connected to the electronic device and the ground contact. This invention provides for a method and electronic package to overcome the difficulties encountered when attempting to simultaneously attach a cover to two different surfaces with two different adhesives.
    Type: Grant
    Filed: October 23, 2003
    Date of Patent: November 16, 2004
    Assignee: International Business Machines Corporation
    Inventors: David Danovitch, Eric Duchesne
  • Patent number: 6809368
    Abstract: A structure and method which enables the deposit of a thin nitride liner just before Trench Top Oxide TTO (High Density Plasma) HDP deposition during the formation of a vertical MOSFET DRAM cell device. This liner is subsequently removed after TTO sidewall etch. One function of this liner is to protect the collar oxide from being etched during the TTO oxide sidewall etch and generally provides lateral etch protection which is not realized in the current processing scheme. The process sequence does not rely on previously deposited films for collar protection, and decouples TTO sidewall etch protection from previous processing steps to provide additional process flexibility, such as allowing a thinner strap Cut Mask nitride and greater nitride etching during node nitride removal and buried strap nitrided interface removal.
    Type: Grant
    Filed: April 11, 2001
    Date of Patent: October 26, 2004
    Assignee: International Business Machines Corporation
    Inventors: Rama Divakaruni, Thomas W. Dyer, Rajeev Malik, Jack A. Mandelman, Venkatachalam C. Jaiprakash
  • Patent number: 6809027
    Abstract: A method for forming high-density self-aligned contacts and interconnect structures in a semiconductor device. A dielectric layer thick enough to contain both interconnect and contact structures is formed on a substrate. A patterned hardmask is formed on the dielectric layer to define both the interconnect and contact structures. The openings for interconnect features are first formed by partially etching the dielectric layer selective to the hardmask. A second mask (e.g., a resist) is used to define the contact openings, and the dielectric layer is etched through the second mask, also selective to the hardmask, to expose the diffusion regions to be contacted. The patterned hardmask is used to help define the contact openings. Conductive material is then deposited in the openings which results in contacts and interconnects that are self-aligned. By first forming the openings for both interconnect and contacts, savings in processing steps may be obtained.
    Type: Grant
    Filed: June 6, 2002
    Date of Patent: October 26, 2004
    Assignee: International Business Machines Corporation
    Inventors: Jay W. Strane, Hiroyuki Akatsu, David M. Dobuzinsky
  • Patent number: 6808981
    Abstract: A memory cell containing double-gated vertical metal oxide semiconductor field effect transistors (MOSFETs) and isolation regions such as shallow trench isolation, STI, regions that are self-aligned to the wordlines and bitlines of the cell are provided. The inventive memory cell substantially eliminates the backgating problem and floating well effects that are typically present in prior art memory cells. A method of fabricating the inventive memory cell is also provided.
    Type: Grant
    Filed: February 27, 2003
    Date of Patent: October 26, 2004
    Assignee: International Business Machines Corporation
    Inventors: Jack A. Mandelman, Ramachandra Divakaruni, Carl J. Radens, Gary B. Bronner
  • Patent number: 6806177
    Abstract: A method for forming high-density self-aligned contacts and interconnect structures in a semiconductor device. A dielectric layer thick enough to contain both interconnect and contact structures is formed on a substrate. A patterned hardmask is formed on the dielectric layer to define both the interconnect and contact structures. The openings for interconnect features are first formed by partially etching the dielectric layer selective to the hardmask. A second mask (e.g., a resist) is used to define the contact openings, and the dielectric layer is etched through the second mask, also selective to the hardmask, to expose the diffusion regions to be contacted. The patterned hardmask is used to help define the contact openings. Conductive material is then deposited in the openings which results in contacts and interconnects that are self-aligned. By first forming the openings for both interconnect and contacts, savings in processing steps may be obtained.
    Type: Grant
    Filed: November 21, 2003
    Date of Patent: October 19, 2004
    Assignee: International Business Machines Corporation
    Inventors: Jay W. Strane, Hiroyuki Akatsu, David M. Dobuzinsky