Syntest Technologies, Inc.

Prolific Technology Inc.

Shih-Chia Kao

Hsin-Po Wang

Xiaoqing Wen

Meng-Chyi Lin

Po-Ching Hsu

Hao-Jan Chao

Laung-Terng Wang

Laung-Terng (l-t) Wang

Shyh-Horng Lin

Fei-Sheng Hsu

Chi-Chan Hsu

Augusli Kifli

Xiaqing Wen

Khader S Abdel-Hafez

Ming-Tung Chang

Shing-Wu Tung

Sen-Wei Tsai

Tsai-Wang Tseng

Laung-Terng (l -t) Wang

Jaehee Lee

Luang-Terng Wang

Hsin-P Wang

Laung-Terng (l T) Wang

A method 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 scan-test or self-test mode, where N&#x3e;1, each clock domain having one capture clock and a plurality of scan cells, each capture clock comprising a plurality of capture clock pulses; said method comprising: (a) generating and shifting-in N test stimuli to all said scan cells within said N clock domains in said integrated circuit or circuit assembly during a shift-in operation; (b) applying an ordered sequence of capture clocks to all said scan cells within said N clock domains, the ordered sequence of capture clocks comprising at least a plurality of capture clock pulses from two or more selected capture clocks placed in a sequential order such that all clock domains are never triggered simultaneously during a capture operation; and (c) analyzing output responses of all said scan cells to locate any faults therein.

Multiple-capture DFT system for detecting or locating crossing clock-domain faults during self-test or scan-test

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).

Computer-aided design system to automate scan synthesis at register-transfer level

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&#x3e;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.

Multiple-capture DFT system for scan-based integrated circuits

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&#x3e;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.

A method and apparatus for testing or diagnosing faults in a scan-based integrated circuit using a unified self-test and scan-test technique. The method and apparatus comprises using a unified test controller to ease prototype debug and production test. The unified test controller further comprises using a capture clock generator and a plurality of domain clock generators each embedded in a clock domain to perform self-test or scan-test. The capture clocks generated by the capture clock generator are used to guide at-speed or reduced-speed self-test (or scan-test) within each clock domain. The frequency of these capture clocks can be totally unrelated to those of system clocks controlling the clock domains. This unified approach allows designers to test or diagnose stuck-type and non-stuck-type faults with a low-cost DFT (design-for-test) tester or a low-cost DFT debugger. A computer-aided design (CAD) method is further developed to realize the method and synthesize the apparatus.

Method and apparatus for unifying self-test with scan-test during prototype debug and production test

A read-only memory (ROM) and a related method for controlling operations of the ROM are disclosed. A built-in self-test (BIST) circuit of the ROM verifies system data stored in a system area of a plurality of memory cells of the ROM according to verification data stored in a verification area of the memory cells of the ROM.

Read-only memory and operational control method thereof

A method and apparatus for inserting design-for-debug (DFD) circuitries in an integrated circuit to debug or diagnose DFT modules, including scan cores, memory BIST (built-in self-test) cores, logic BIST cores, and functional cores. The invention further comprises using a DFD controller for executing a plurality of DFD commands to debug or diagnosis the DFT modules embedded with the DFD circuitries. When used alone or combined together, these DFD commands will detect or locate physical failures in the DFT modules in the integrated circuit on an evaluation board or system using a low-cost DFT debugger. A computer-aided design (CAD) method is further developed to synthesize the DFD controller and DFD circuitries according to the IEEE 1149.1 Boundary-scan Std. The DFD controller supports, but is not limited to, the following DFD commands: RUN_SCAN, RUN_MBIST, RUN_LBIST, DBG_SCAN, DBG_MBIST, DBG_LBIST, DBG_FUNCTION, SELECT, SHIFT, SHIFT_CHAIN, CAPTURE, RESET, BREAK, RUN, STEP, and STOP.

Method and apparatus for diagnosing failures in an integrated circuit using design-for-debug (DFD) techniques

A method and apparatus for debug, diagnosis, and/or yield improvement of a scan-based integrated circuit where scan chains embedded in a scan corehave no external access, such as the case when they are surrounded by pattern generatorsand pattern compactors, using a DFT (design-for-test) technology such as Logic BIST (built-in self-test) or Compressed Scan. This invention includes an output-mask controllerand an output-mask networkto allow designers to mask off selected scan cellsfrom being compacted in a selected pattern compactor. 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. Computer-aided design (CAD) methods are then proposed to automatically synthesize the output-mask controller, output-mask network, input chain-mask controller and input-mask network, and to further generate test patterns according to the synthesized scan-based integrated circuit.

Method and apparatus for debug, diagnosis, and yield improvement of scan-based integrated circuits

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Taipei, Taiwan

Shih-Chia Kao