Patents by Inventor Shih-Cheng Hsueh

Shih-Cheng Hsueh 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: 7032194
    Abstract: A method for dealing with process specific physical effects applies dimensional modifications to an IC layout to compensate for performance variations caused by the physical effects. Because the dimensional modifications harmonize the performance of the actual IC with the performance of the IC model, time-consuming re-verification operations are not required. Current drive variations caused by shallow trench isolation (STI) stress can be compensated for by adjusting the gate dimensions of the affected transistors to increase or decrease current drive as necessary. Such physical effect compensation can be applied before, after, or even concurrently with optical proximity correction (OPC). The dimensional modifications for physical effect compensation can also be incorporated into an OPC engine.
    Type: Grant
    Filed: February 19, 2003
    Date of Patent: April 18, 2006
    Assignee: Xilinx, Inc.
    Inventors: Shih-Cheng Hsueh, Xiao-Jie Yuan, Daniel Gitlin
  • Patent number: 6878561
    Abstract: Described are mask-alignment detection structures that measure both the direction and extent of misalignment between layers of an integrated circuit using resistive elements for which resistance varies with misalignment in one dimension. Measurements in accordance with the invention are relatively insensitive to process variations, and the structures using to take these measurements can be formed along with other features on an integrated circuit using standard processes. One embodiment of the invention may be used to measure misalignment between two conductive layers. Other embodiments measure misalignment between diffusion regions and conductors and between diffusion regions and windows through which other diffusion regions are to be formed. A circuit in accordance with one embodiment includes row and column decoders for independently selecting mask-alignment detection structures to reduce the number of test terminals required to implement the detection structures.
    Type: Grant
    Filed: October 7, 2003
    Date of Patent: April 12, 2005
    Assignee: Xilinx, Inc.
    Inventors: Kevin T. Look, Shih-Cheng Hsueh
  • Publication number: 20040072398
    Abstract: Described are mask-alignment detection structures that measure both the direction and extent of misalignment between layers of an integrated circuit using resistive elements for which resistance varies with misalignment in one dimension. Measurements in accordance with the invention are relatively insensitive to process variations, and the structures using to take these measurements can be formed along with other features on an integrated circuit using standard processes. One embodiment of the invention may be used to measure misalignment between two conductive layers. Other embodiments measure misalignment between diffusion regions and conductors and between diffusion regions and windows through which other diffusion regions are to be formed. A circuit in accordance with one embodiment includes row and column decoders for independently selecting mask-alignment detection structures to reduce the number of test terminals required to implement the detection structures.
    Type: Application
    Filed: October 7, 2003
    Publication date: April 15, 2004
    Applicant: Xilinx, Inc.
    Inventors: Kevin T. Look, Shih-Cheng Hsueh
  • Patent number: 6716653
    Abstract: An electrical alignment test structure enables monitoring and measuring misalignment between layers (or associated masks) of an IC. The alignment test structure comprises a target region and an alignment feature in different layers. The target region and the alignment feature may be formed in diffusion and polysilicon layers, respectively or in well and diffusion layers, respectively. In both embodiments, the alignment feature controls the size of a conductive channel in the target region. Misalignment can be checked by comparing channel resistance with a baseline (no misalignment) resistance. In another embodiment, the target region and alignment feature are formed in the diffusion and polysilicon layers, respectively, wherein the alignment feature controls the relative widths of the source and drain regions. Misalignment can be checked by comparing current flow with a baseline current.
    Type: Grant
    Filed: October 24, 2002
    Date of Patent: April 6, 2004
    Assignee: Xilinx, Inc.
    Inventors: Kevin T. Look, Shih-Cheng Hsueh
  • Patent number: 6684520
    Abstract: Described are mask-alignment detection structures that measure both the direction and extent of misalignment between layers of an integrated circuit using resistive elements for which resistance varies with misalignment in one dimension. Measurements in accordance with the invention are relatively insensitive to process variations, and the structures using to take these measurements can be formed along with other features on an integrated circuit using standard processes. One embodiment of the invention may be used to measure misalignment between two conductive layers. Other embodiments measure misalignment between diffusion regions and conductors and between diffusion regions and windows through which other diffusion regions are to be formed. A circuit in accordance with one embodiment includes row and column decoders for independently selecting mask-alignment detection structures to reduce the number of test terminals required to implement the detection structures.
    Type: Grant
    Filed: February 25, 2000
    Date of Patent: February 3, 2004
    Assignee: Xilinx, Inc.
    Inventors: Kevin T. Look, Shih-Cheng Hsueh
  • Patent number: 6569576
    Abstract: A reticle and pellicle that are modified to prevent ESD damage to the masking material between portions of the lithographic mask pattern on the reticle during an integrated circuit fabrication process. The modification involves providing conducting lines on the glass side of the reticle and on the surface of the pellicle to balance any buildup of electrostatic charges on those devices, thereby reducing or eliminating the induction of opposite charges onto adjacent mask pattern features on the reticle and preventing the melting and bridging of those mask pattern features and the defects caused by such melting or bridging. The conductive metal lines may have a smaller width than the smallest resolution value of the reduction lens used in the mask pattern transfer process, and may also be located outside of the focal plane of the reduction lens to avoid transfer of the images of the conductive lines onto the target semiconductor substrate during the mask pattern transfer process.
    Type: Grant
    Filed: September 27, 2000
    Date of Patent: May 27, 2003
    Assignee: Xilinx, Inc.
    Inventors: Shih-Cheng Hsueh, Kevin T. Look, Jonathan Jung-Ching Ho
  • Patent number: 6563320
    Abstract: An electrical alignment test structure enables monitoring and measuring misalignment between layers (or associated masks) of an IC. The alignment test structure comprises a target region and an alignment feature in different layers. The target region and the alignment feature may be formed in diffusion and polysilicon layers, respectively or in well and diffusion layers, respectively. In both embodiments, the alignment feature controls the size of a conductive channel in the target region. Misalignment can be checked by comparing channel resistance with a baseline (no misalignment) resistance. In another embodiment, the target region and alignment feature are formed in the diffusion and polysilicon layers, respectively, wherein the alignment feature controls the relative widths of the source and drain regions. Misalignment can be checked by comparing current flow with a baseline current.
    Type: Grant
    Filed: December 15, 2000
    Date of Patent: May 13, 2003
    Assignee: Xilinx, Inc.
    Inventors: Kevin T. Look, Shih-Cheng Hsueh
  • Publication number: 20030049872
    Abstract: An electrical alignment test structure enables monitoring and measuring misalignment between layers (or associated masks) of an IC. The alignment test structure comprises a target region and an alignment feature in different layers. The target region and the alignment feature may be formed in diffusion and polysilicon layers, respectively or in well and diffusion layers, respectively. In both embodiments, the alignment feature controls the size of a conductive channel in the target region. Misalignment can be checked by comparing channel resistance with a baseline (no misalignment) resistance. In another embodiment, the target region and alignment feature are formed in the diffusion and polysilicon layers, respectively, wherein the alignment feature controls the relative widths of the source and drain regions. Misalignment can be checked by comparing current flow with a baseline current.
    Type: Application
    Filed: October 24, 2002
    Publication date: March 13, 2003
    Applicant: Xilinx, Inc.
    Inventors: Kevin T. Look, Shih-Cheng Hsueh
  • Patent number: 6465305
    Abstract: Described are mask-alignment detection structures that measure both the direction and extent of misalignment between layers of an integrated circuit. Each structure includes one or more MOS transistors, each of which exhibits a threshold voltage that varies with misalignment in one dimension. The test structures are configured in mirrored pairs, so that misalignment in one direction oppositely affects the threshold voltages of the paired structures. The threshold voltages of the paired structures can therefore be compared to determine the extent and direction of misalignment. Measurements in accordance with the invention are relatively insensitive to process variations, and the structures using to take these measurements can be formed along with other features on an integrated circuit using standard processes. One embodiment of the invention may be used to measure misalignment between active implants and the windows in which active regions are formed.
    Type: Grant
    Filed: January 8, 2002
    Date of Patent: October 15, 2002
    Assignee: Xilinx, Inc.
    Inventors: Kevin T. Look, Shih-Cheng Hsueh
  • Patent number: 6436726
    Abstract: Mask-alignment detection structures that measure both the direction and extent of misalignment between layers of an integrated circuit using resistive elements for which resistance varies with misalignment in one dimension. Measurements in accordance with the invention are relatively insensitive to process variations, and the structures using to take these measurements can be formed along with other features on an integrated circuit using standard processes. One embodiment of the invention may be used to measure misalignment between two conductive layers. Other embodiments measure misalignment between diffusion regions and conductors and between diffusion regions and windows through which other diffusion regions are to be formed. A circuit in accordance with one embodiment includes row and column decoders for independently selecting mask-alignment detection structures to reduce the number of test terminals required to implement the detection structures.
    Type: Grant
    Filed: July 16, 2001
    Date of Patent: August 20, 2002
    Assignee: Xilinx, Inc.
    Inventors: Kevin T. Look, Shih-Cheng Hsueh
  • Patent number: 6426534
    Abstract: Described are mask-alignment detection structures that measure both the direction and extent of misalignment between layers of an integrated circuit. Each structure includes one or more MOS transistors, each of which exhibits a threshold voltage that varies with misalignment in one dimension. The test structures are configured in mirrored pairs, so that misalignment in one direction oppositely affects the threshold voltages of the paired structures. The threshold voltages of the paired structures can therefore be compared to determine the extent and direction of misalignment. Measurements in accordance with the invention are relatively insensitive to process variations, and the structures using to take these measurements can be formed along with other features on an integrated circuit using standard processes. One embodiment of the invention may be used to measure misalignment between active implants and the windows in which active regions are formed.
    Type: Grant
    Filed: May 1, 2000
    Date of Patent: July 30, 2002
    Assignee: Xilinx, Inc.
    Inventors: Kevin T. Look, Shih-Cheng Hsueh
  • Patent number: 6393714
    Abstract: Described are mask-alignment detection structures that measure both the direction and extent of misalignment between layers of an integrated circuit using resistive elements for which resistance varies with misalignment in one dimension. Measurements in accordance with the invention are relatively insensitive to process variations, and the structures using to take these measurements can be formed along with other features on an integrated circuit using standard processes. One embodiment of the invention may be used to measure misalignment between two conductive layers. Other embodiments measure misalignment between diffusion regions and conductors and between diffusion regions and windows through which other diffusion regions are to be formed. A circuit in accordance with one embodiment includes row and column decoders for independently selecting mask-alignment detection structures to reduce the number of test terminals required to implement the detection structures.
    Type: Grant
    Filed: February 25, 2000
    Date of Patent: May 28, 2002
    Assignee: Xilinx, Inc.
    Inventors: Kevin T. Look, Shih-Cheng Hsueh
  • Publication number: 20010049881
    Abstract: Described are mask-alignment detection structures that measure both the direction and extent of misalignment between layers of an integrated circuit using resistive elements for which resistance varies with misalignment in one dimension. Measurements in accordance with the invention are relatively insensitive to process variations, and the structures using to take these measurements can be formed along with other features on an integrated circuit using standard processes. One embodiment of the invention may be used to measure misalignment between two conductive layers. Other embodiments measure misalignment between diffusion regions and conductors and between diffusion regions and windows through which other diffusion regions are to be formed. A circuit in accordance with one embodiment includes row and column decoders for independently selecting mask-alignment detection structures to reduce the number of test terminals required to implement the detection structures.
    Type: Application
    Filed: July 16, 2001
    Publication date: December 13, 2001
    Applicant: Xilinx, Inc.
    Inventors: Kevin T. Look, Shih-Cheng Hsueh
  • Patent number: 6305095
    Abstract: Described are mask-alignment detection structures that measure both the direction and extent of misalignment between layers of an integrated circuit using resistive elements for which resistance varies with misalignment in one dimension. Measurements in accordance with the invention are relatively insensitive to process variations, and the structures using to take these measurements can be formed along with other features on an integrated circuit using standard processes. One embodiment of the invention may be used to measure misalignment between two conductive layers. Other embodiments measure misalignment between diffusion regions and conductors and between diffusion regions and windows through which other diffusion regions are to be formed. A circuit in accordance with one embodiment includes row and column decoders for independently selecting mask-alignment detection structures to reduce the number of test terminals required to implement the detection structures.
    Type: Grant
    Filed: February 25, 2000
    Date of Patent: October 23, 2001
    Assignee: Xilinx, Inc.
    Inventors: Kevin T. Look, Shih-Cheng Hsueh