Patents Assigned to Syntest Technologies, Inc.
  • Patent number: 7124342
    Abstract: A method for generating stimuli and test responses for testing faults in a scan-based integrated circuit in a selected scan-test mode or a selected self-test mode, the scan-based integrated circuit containing a plurality of scan chains, N clock domains, and C cross-clock domain blocks, each scan chain comprising multiple scan cells coupled in series, each clock domain having one capture clock, each cross-clock domain block comprising a combinational logic network.
    Type: Grant
    Filed: May 21, 2004
    Date of Patent: October 17, 2006
    Assignee: Syntest Technologies, Inc.
    Inventors: Laung-Terng Wang, Khader S. Abdel-Hafez, Xiaoqing Wen, Boryau (Jack) Sheu, Shun-Miin (Sam) Wang
  • Publication number: 20060156122
    Abstract: A method and apparatus for selectively masking off unknown (‘x’) captured scan data in first selected scan cells 220 from propagating through the scan chains 221 for test, debug, diagnosis, and yield improvement of a scan-based integrated circuit 207 in a selected scan-test mode 232 or selected self-test mode. The scan-based integrated circuit 207 contains a plurality of scan chains 221, a plurality of pattern generators 208, a plurality of pattern compactors 213, with each scan chain 221 comprising multiple scan cells 220, 222 coupled in series. The method and apparatus further includes an output-mask controller 211 and an output-mask network 212 embedded on the scan data input path of second selected scan cells 222, or a set/reset controller controlling selected set/reset inputs of second selected scan cells. A synthesis method is also proposed for synthesizing the output-mask controller 211 and the set/reset controller.
    Type: Application
    Filed: February 10, 2006
    Publication date: July 13, 2006
    Applicant: Syntest Technologies, Inc.
    Inventors: Laung-Terng Wang, Xiaoqing Wen, Boryau Sheu
  • Patent number: 7058869
    Abstract: A method and apparatus for debug, diagnosis, and/or yield improvement of a scan-based integrated circuit where scan chains embedded in a scan core 303 have no external access, such as the case when they are surrounded by pattern generators 302 and pattern compactors 305, using a DFT (design-for-test) technology such as Logic BIST (built-in self-test) or Compressed Scan. This invention includes an output-mask controller 301 and an output-mask network 304 to allow designers to mask off selected scan cells 311 from being compacted in a selected pattern compactor 305. This invention also includes an input chain-mask controller and an input-mask network for driving constant logic values into scan chain inputs of selected scan chains to allow designers to recover from scan chain hold time violations.
    Type: Grant
    Filed: January 23, 2004
    Date of Patent: June 6, 2006
    Assignee: Syntest Technologies, Inc.
    Inventors: Khader S. Abdel-Hafez, Xiaoqing Wen, Laung-Terng Wang, Po-Ching Hsu, Shih-Chia Kao, Hao-Jan Chao, Hsin-Po Wang
  • Patent number: 7032148
    Abstract: A method and apparatus for selectively masking off unknown (‘x’) captured scan data in first selected scan cells 220 from propagating through the scan chains 221 for test, debug, diagnosis, and yield improvement of a scan-based integrated circuit 207 in a selected scan-test mode 232 or selected self-test mode. The scan-based integrated circuit 207 contains a plurality of scan chains 221, a plurality of pattern generators 208, a plurality of pattern compactors 213, with each scan chain 221 comprising multiple scan cells 220, 222 coupled in series. The method and apparatus further includes an output-mask controller 211 and an output-mask network 212 embedded on the scan data input path of second selected scan cells 222, or a set/reset controller controlling selected set/reset inputs of second selected scan cells. A synthesis method is also proposed for synthesizing the output-mask controller 211 and the set/reset controller.
    Type: Grant
    Filed: June 28, 2004
    Date of Patent: April 18, 2006
    Assignee: Syntest Technologies, Inc.
    Inventors: Laung-Terng (L.-T.) Wang, Shun-Miin (Sam) Wang, Khader S. Abdel-Hafez, Xiaoqing Wen, Boryau (Jack) Sheu
  • Patent number: 7007213
    Abstract: A method and apparatus for providing ordered capture clocks to detect or locate faults within N clock domains and faults crossing any two clock domains in an integrated circuit or circuit assembly in self-test or scan-test mode, where N>1 and each domain has a plurality of scan cells. The method and apparatus allows generating and loading N pseudorandom or predetermined stimuli to all the scan cells within the N clock domains in the integrated circuit or circuit assembly during the shift operation, applying an ordered sequence of capture clocks to all the scan cells within the N clock domains during the capture operation, compacting or comparing N output responses of all the scan cells for analysis during the compact/compare operation, and repeating the above process until a predetermined limiting criteria is reached. A computer-aided design (CAD) system is further developed to realize the method and synthesize the apparatus.
    Type: Grant
    Filed: February 7, 2002
    Date of Patent: February 28, 2006
    Assignee: Syntest Technologies, Inc.
    Inventors: Laung-Terng (L.-T.) Wang, Po-Ching Hsu, Shih-Chia Kao, Meng-Chyi Lin, Hsin-Po Wang, Hao-Jan Chao, Xiaoqing Wen
  • Publication number: 20050235186
    Abstract: A method and apparatus for providing ordered capture clocks to detect or locate faults within N clock domains and faults crossing any two clock domains in a scan-based integrated circuit or circuit assembly in self-test or scan-test mode, where N>1 and each domain has a plurality of scan cells. The method and apparatus will apply an ordered sequence of capture clocks to all scan cells within N clock domains where one or more capture clocks must contain one or more shift clock pulses during the capture operation. A computer-aided design (CAD) method is further developed to realize the method and synthesize the apparatus. In order to further improve the circuit's fault coverage, a CAD method and apparatus are further developed to minimize the memory usage and generate scan patterns for full-scan and feed-forward partial-scan designs containing transparent storage cells, asynchronous set/reset signals, tri-state busses, and low-power gated clocks.
    Type: Application
    Filed: June 14, 2005
    Publication date: October 20, 2005
    Applicant: Syntest Technologies, Inc.
    Inventors: Laung-Terng Wang, Meng-Chyi Lin, Xiaoqing Wen, Hsin-Po Wang, Chi-Chan Hsu, Shih-Chia Kao, Fei-Sheng Hsu
  • Patent number: 6957403
    Abstract: A method and system to automate scan synthesis at register-transfer level (RTL). The method and system will produce scan HDL code modeled at RTL for an integrated circuit modeled at RTL. The method and system comprise computer-implemented steps of performing RTL testability analysis, clock-domain minimization, scan selection, test point selection, scan repair and test point insertion, scan replacement and scan stitching, scan extraction, interactive scan debug, interactive scan repair, and flush/random test bench generation. In addition, the present invention further comprises a method and system for hierarchical scan synthesis by performing scan synthesis module-by-module and then stitching these scanned modules together at top-level. The present invention further comprises integrating and verifying the scan HDL code with other design-for-test (DFT) HDL code, including boundary-scan and logic BIST (built-in self-test).
    Type: Grant
    Filed: March 28, 2002
    Date of Patent: October 18, 2005
    Assignee: Syntest Technologies, Inc.
    Inventors: Laung-Terng Wang, Augusli Kifli, Fei-Sheng Hsu, Shih-Chia Kao, Xiaoqing Wen, Shyh-Horng Lin, Hsin-P Wang
  • Publication number: 20050229123
    Abstract: A method and system to automate scan synthesis at register-transfer level (RTL). The method and system will produce scan HDL code modeled at RTL for an integrated circuit modeled at RTL. The method and system comprise computer-implemented steps of performing RTL testability analysis, clock-domain minimization, scan selection, test point selection, scan repair and test point insertion, scan replacement and scan stitching, scan extraction, interactive scan debug, interactive scan repair, and flush/random test bench generation. In addition, the present invention further comprises a method and system for hierarchical scan synthesis by performing scan synthesis module-by-module and then stitching these scanned modules together at top-level. The present invention further comprises integrating and verifying the scan HDL code with other design-for-test (DFT) HDL code, including boundary-scan and logic BIST (built-in self-test).
    Type: Application
    Filed: April 22, 2005
    Publication date: October 13, 2005
    Applicant: Syntest Technologies, Inc.
    Inventors: Laung-Terng Wang, Xiaoqing Wen, Shyh-Horng Lin
  • Patent number: 6954887
    Abstract: A method and apparatus for providing ordered capture clocks to detect or locate faults within N clock domains and faults crossing any two clock domains in a scan-based integrated circuit or circuit assembly in self-test or scan-test mode, where N>1 and each domain has a plurality of scan cells. The method and apparatus will apply an ordered sequence of capture clocks to all scan cells within N clock domains where one or more capture clocks must contain one or more shift clock pulses during the capture operation. A computer-aided design (CAD) method is further developed to realize the method and synthesize the apparatus. In order to further improve the circuit's fault coverage, a CAD method and apparatus are further developed to minimize the memory usage and generate scan patterns for full-scan and feed-forward partial-scan designs containing transparent storage cells, asynchronous set/reset signals, tri-state busses, and low-power gated clocks.
    Type: Grant
    Filed: March 20, 2002
    Date of Patent: October 11, 2005
    Assignee: Syntest Technologies, Inc.
    Inventors: Laung-Terng (L.-T.) Wang, Meng-Chyi Lin, Xiaoqing Wen, Hsin-Po Wang, Chi-Chan Hsu, Shih-Chia Kao, Fei-Sheng Hsu