Abstract: A method for performing robust scan synthesis for soft-error protection on a design for generating a robust scan design in a system. The system is modeled selectively at a register-transfer level (RTL) or a gate level; the design includes at least a sequential element or a scan cell for mapping to a robust scan cell of a select robust scan cell type. The method comprises performing a scan replacement and a scan stitching on the design database based on a given control information file for synthesizing the robust scan cell on the design database; and generating the synthesized robust scan design at a pre-determined RTL or a pre-determined gate level.

Abstract: 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>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.

Abstract: A low-pin-count scan compression method and apparatus for reducing test data volume and test application time in a scan-based integrated circuit. The scan-based integrated circuit contains one or more scan chains, each scan chain comprising one or more scan cells coupled in series. The method and apparatus includes a programmable pipelined decompressor comprising one or more shift registers, a combinational logic network, and an optional scan connector. The programmable pipelined decompressor decompresses a compressed scan pattern on its compressed scan inputs and drives the generated decompressed scan pattern at the output of the programmable pipelined decompressor to the scan data inputs of the scan-based integrated circuit. Any input constraints imposed by said combinational logic network are incorporated into an automatic test pattern generation (ATPG) program for generating the compressed scan pattern for one or more selected faults in one-step.

Abstract: A low-pin-count scan compression method and apparatus for reducing test data volume and test application time in a scan-based integrated circuit. The scan-based integrated circuit contains one or more scan chains, each scan chain comprising one or more scan cells coupled in series. The method and apparatus includes a programmable pipelined decompressor comprising one or more shift registers, a combinational logic network, and an optional scan connector. The programmable pipelined decompressor decompresses a compressed scan pattern on its compressed scan inputs and drives the generated decompressed scan pattern at the output of the programmable pipelined decompressor to the scan data inputs of the scan-based integrated circuit. Any input constraints imposed by said combinational logic network are incorporated into an automatic test pattern generation (ATPG) program for generating the compressed scan pattern for one or more selected faults in one-step.

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).

Abstract: A low-pin-count scan compression method and apparatus for reducing test data volume and test application time in a scan-based integrated circuit. The scan-based integrated circuit contains one or more scan chains, each scan chain comprising one or more scan cells coupled in series. The method and apparatus includes a programmable pipelined decompressor comprising one or more shift registers, a combinational logic network, and an optional scan connector. The programmable pipelined decompressor decompresses a compressed scan pattern on its compressed scan inputs and drives the generated decompressed scan pattern at the output of the programmable pipelined decompressor to the scan data inputs of the scan-based integrated circuit. Any input constraints imposed by said_combinational logic network are incorporated into an automatic test pattern generation (ATPG) program for generating the compressed scan pattern for one or more selected faults in one-step.

Abstract: A method for performing robust scan synthesis for soft-error protection on a design for generating a robust scan design in a system. The system is modeled selectively at a register-transfer level (RTL) or a gate level; the design includes at least a sequential element or a scan cell for mapping to a robust scan cell of a select robust scan cell type. The method comprises performing a scan replacement and a scan stitching on the design database based on a given control information file for synthesizing the robust scan cell on the design database; and generating the synthesized robust scan design at a pre-determined RTL or a pre-determined gate level.

Abstract: A method for automatically generating test patterns using a close-to-minimum number of configurations for a Field Programmable Gate Array (FPGA) to reduce test data volume and test application time. The FPGA can be a standalone programmable device or a circuit embedded in an Application Specific Integrated Circuit (ASIC).

Abstract: An apparatus and method for soft-error resilience or correction with the ability to perform a manufacturing test operation, a slow-speed snapshot operation, a slow-speed signature analysis operation, an at-speed signature analysis operation, a defect tolerance operation, or any combination of the above operations. In one embodiment, an apparatus includes a system circuit, a shadow circuit, and an output joining circuit for soft-error resilience. The output joining circuit coupled to the output terminals of the system circuit and the shadow circuit includes at least an S-element for defect tolerance. In another embodiment, an apparatus includes a system circuit, a shadow circuit, a debug circuit, and an output joining circuit for soft-error correction. The output joining circuit coupled to the output terminals of the system circuit, the shadow circuit, and the debug circuit includes at least a V-element for defect tolerance.

Abstract: 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>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.

Abstract: A memory redundancy reconfiguration for N base blocks associated with k redundant blocks. The data will be written into both base blocks and defect-free redundant blocks if the base blocks are defective; k multiplexers MUXRi each having N input signals (d0 to dN?1) capable of being connected to k input signals of the redundant blocks; N multiplexers MUXi each having k+1 input signals from k redundant blocks (R0 to Rk?1) and one base block (Ni), capable of being connected to N output signals (qi); and logic means associated with each multiplexer, to convert the input signals of the multiplexer to its output signal.

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.

Abstract: 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.

Abstract: A hybrid clocking scheme for simultaneously detecting a b-cycle path-delay fault in a b-cycle (false) path and a c-cycle path-delay fault in a c-cycle (false) path using at least n+1 at-speed clock pulses during a capture operation in a clock domain in a scan design or a scan-based BIST design, where 1<=b<=c<=n. The scan design or BIST design includes multiple scan chains, each scan chain comprising multiple scan cells coupled in series. The design includes one or more clock domains each running at its intended operating frequency or at-speed. The hybrid clocking scheme comprises at least one at-speed shift clock pulse or one at-speed capture clock pulse immediately followed by at least two at-speed capture clock pulses during the capture operation to simultaneously detect the b-cycle path-delay fault and the c-cycle path-delay fault within the clock domain.

Abstract: A broadcaster, system, and method for reducing test data volume and test application time in an ATE (automatic test equipment) in a scan-based integrated circuit. The scan-based integrated circuit contains multiple scan chains, each scan chain comprising multiple scan cells coupled in series. The broadcaster is a combinational logic network coupled to an optional virtual scan controller and an optional scan connector. The virtual scan controller controls the operation of the broadcaster. The system transmits virtual scan patterns stored in the ATE and generates broadcast scan patterns through the broadcaster for testing manufacturing faults in the scan-based integrated circuit. The number of scan chains that can be supported by the ATE is significantly increased. Methods are further proposed to reorder scan cells in selected scan chains, to generate the broadcast scan patterns and virtual scan patterns, and to synthesize the broadcaster and a compactor in the scan-based integrated circuit.

Abstract: A memory redundancy reconfiguration for N base blocks associated with k redundant blocks. The data will be written into both base blocks and defect-free redundant blocks if the base blocks are defective; k multiplexers MUXRi each having N input signals (d0 to dN?1) capable of being connected to k input signals of the redundant blocks; N multiplexers MUXi each having k+1 input signals from k redundant blocks (R0 to Rk?1) and one base block (Ni), capable of being connected to N output signals (qi); and logic means associated with each multiplexer, to convert the input signals of the multiplexer to its output signal.

Abstract: A broadcaster, system, and method for reducing test data volume and test application time in an ATE (automatic test equipment) in a scan-based integrated circuit. The scan-based integrated circuit contains multiple scan chains, each scan chain comprising multiple scan cells coupled in series. The broadcaster is a combinational logic network coupled to an optional virtual scan controller and an optional scan connector. The virtual scan controller controls the operation of the broadcaster. The system transmits virtual scan patterns stored in the ATE and generates broadcast scan patterns through the broadcaster for testing manufacturing faults in the scan-based integrated circuit. The number of scan chains that can be supported by the ATE is significantly increased. Methods are further proposed to reorder scan cells in selected scan chains, to generate the broadcast scan patterns and virtual scan patterns, and to synthesize the broadcaster and a compactor in the scan-based integrated circuit.

Abstract: A broadcaster, system, and method for reducing test data volume and test application time in an ATE (automatic test equipment) in a scan-based integrated circuit. The scan-based integrated circuit contains multiple scan chains, each scan chain comprising multiple scan cells coupled in series. The broadcaster is a combinational logic network coupled to an optional virtual scan controller and an optional scan connector. The virtual scan controller controls the operation of the broadcaster. The system transmits virtual scan patterns stored in the ATE and generates broadcast scan patterns through the broadcaster for testing manufacturing faults in the scan-based integrated circuit. The number of scan chains that can be supported by the ATE is significantly increased. Methods are further proposed to reorder scan cells in selected scan chains, to generate the broadcast scan patterns and virtual scan patterns, and to synthesize the broadcaster and a compactor in the scan-based integrated circuit.

Abstract: A method and apparatus time-division demultiplexes and decompresses a compressed input stimulus provided at a selected data rate R1, into a decompressed stimulus, driven at a selected data rate R2, for driving selected scan chains in a scan-based integrated circuit using a plurality of time-division demultiplexors and time-division multiplexors for shifting stimuli and test responses in and out of high-speed I/O pads in order to reduce test time, test cost, and scan pin count. A synthesis method is also proposed for synthesizing the time-division multiplexors, decompressors, compressors, and time-division multiplexors.

Abstract: 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.