A method and circuit are provided for implementing enhanced scan data testing for test time reduction and decreased scan data interdependence with on product multiple input signature register (OPMISR++) testing, and a design structure on which the subject circuit resides. A respective Pseudo-Random Pattern Generator (PRPG) provides channel input patterns to a respective associated scan channel used for the OPMISR++ diagnostics. Control inputs are coupled to the Pseudo-Random Pattern Generator (PRPG) providing PRPG control distribution. The PRPG selectively provides controlled channel input patterns for the respective scan channel responsive to the control inputs.

Disclosed herein are exemplary embodiments of a so-called “X-press” test response compactor. Certain embodiments of the disclosed compactor comprise an overdrive section and scan chain selection logic. Certain embodiments of the disclosed technology offer compaction ratios on the order of 1000×. Exemplary embodiments of the disclosed compactor can maintain about the same coverage and about the same diagnostic resolution as that of conventional scan-based test scenarios. Some embodiments of a scan chain selection scheme can significantly reduce or entirely eliminate unknown states occurring in test responses that enter the compactor. Also disclosed herein are embodiments of on-chip comparator circuits and methods for generating control circuitry for masking selection circuits.

A circuit comprises scan gating devices inserted between outputs of scan chains and inputs of a test response compactor. The scan gating devices divides the scan chains into groups of scan chains. Each of the scan gating devices operates in either an enabled mode or a disenabled mode based on a first signal. A scan gating device operating in the enabled mode blocks, blocks only at some clock cycles, or does not block a portion of a test response of a test pattern captured by and outputted from a scan chain in the associated scan chain group based on a second signal. Scan gating devices operating in the disenabled mode do not block, or based on a third signal, either block or do not block, a portion of the test response captured by and outputted from all scan chains in each of the associated scan chain groups.

Systems and methods are provided for an integrated circuit system. A plurality of separate integrated circuit dies are coupled together to form an integrated circuit package, a first integrated circuit die including an input and a last integrated circuit die including an output, ones of the plurality of integrated circuit dies including a testing circuit associated with a corresponding integrated circuit die. The testing circuit includes a testing path for testing functionality of the corresponding integrated circuit die, a bypass path bypassing the testing path, and control circuitry for selecting between an output of the testing path and an output of the bypass path, the control circuitry being configured to select the output of the testing path or the output of the bypass path and to pass the selected output to a subsequent integrated circuit die among the plurality of coupled circuit dies.

The invention relates to a microchip with a multiplicity of reconfigurable test structures, wherein the microchip has a test input (TDI) and a test output (TDO), wherein the multiplicity of test structures can be connected to the test input (TDI) and the test output (TDO), wherein one intermediate memory is provided for each of the multiplicity of test structures, wherein each of the multiplicity of test structures can be tested separately and concurrently with the aid of the respective intermediate memory and a corresponding individual control.

Aspects of the invention provide for reducing BIST test time for a memory of an IC chip. In one embodiment, a BIST architecture for reducing BIST test time of a memory for an integrated circuit (IC) chip, the architecture comprising: a pair of latches for receiving bursts of data from a memory; a first compression stage for receiving a burst of data and compressing the burst of data into a plurality of latches; a second compression stage for comparing the compressed bursts of data with expected data; and a logic gate for determining whether there is a fail in the burst of data.

Systems and methods for a sequential decompressor which builds equations predictably provide a first-in, first out (“FIFO”) shift register which is fed by a first XOR decompressor and provides outputs to a second XOR decompressor.

Systems and methods efficiently bring additional variables into a Pseudo-Random Pattern Generator (“PRPG”) in the early cycles of an automatic test pattern generation (“ATPG”) process without utilizing any additional hardware or control pins. Overscanning (e.g., scanning longer than the length of the longest channel) for some additional cycles brings in enough variables into the PRPG. Data corresponding to earlier cycles of the ATPG process is removed.

A scan chain for testing a combinatorial logic circuit includes a first scan chain path of flip-flops connected to the combinatorial logic circuit for functional mode operation during runtime of the combinatorial logic circuit. A second scan chain path of flip-flops is also connected to the combinatorial logic circuit and supports both a shift mode and a capture mode. The second scan chain path operates in shift mode while the first scan chain path is connected to the combinatorial logic circuit for functional mode operation. The second scan chain is then connected to the combinatorial logic circuit when run time is interrupted and operates in capture mode to apply the test data to the combinatorial logic circuit.

According to one embodiment, a semiconductor integrated circuit includes: a logic circuit including a first scan chain configured to operate based on a first clock signal and a second scan chain configured to operate based on a second clock signal in a built-in self-test; a pattern generator configured to generate a test pattern and transmit the test pattern to the first and second scan chains; a compression circuit configured to compress first data received from the first and second scan chains; a clock select circuit configured to select one of the first and second clock signals and transmit the one of the first and second clock signals to the corresponding one of the first and second scan chains in the test; and a test control circuit configured to control the test and detect a fault in the logic circuit based on a result of the test.