摘要:
The invention provides a circuit that can observe data within shift registers without altering the data. The circuit includes selectors connected to the inputs and outputs of the shift registers. The selectors selectively connect the input with the output of a selected shift register to form a wiring loop for the selected shift register. A control device connected to the wiring loop uses the wiring loop to cause the data to be continually transferred from the output of the selected shift register to the input of the selected shift register and back through the selected shift register in a circular manner. The control device includes a counter used for determining the length of a selected shift register and a set of registers to store, for future use when rotating data in the shift registers, the length of each shift register. The control device also includes a data output accessible from outside the circuit. An observation wire is connected to the wiring loop, and the data passes from the wiring loop to the control device through the observation wire. The control device outputs data appearing on the wiring loop as the data is circulated through the selected shift register to permit data within the selected shift register to be observed outside the circuit without altering the data within the selected shift register.
摘要:
The invention provides a circuit that can observe data within shift registers without altering the data. The circuit includes selectors connected to the inputs and outputs of the shift registers. The selectors selectively connect the input with the output of a selected shift register to form a wiring loop for the selected shift register. A control device connected to the wiring loop uses the wiring loop to cause the data to be continually transferred from the output of the selected shift register to the input of the selected shift register and back through the selected shift register in a circular manner. The control device includes a counter used for determining the length of a selected shift register and a set of registers to store, for future use when rotating data in the shift registers, the length of each shift register. The control device also includes a data output accessible from outside the circuit. An observation wire is connected to the wiring loop, and the data passes from the wiring loop to the control device through the observation wire. The control device outputs data appearing on the wiring loop as the data is circulated through the selected shift register to permit data within the selected shift register to be observed outside the circuit without altering the data within the selected shift register.
摘要:
A chip repair system designed for automated test equipment independent application on many unique very dense ASIC devices in a high turnover environment is disclosed. During test, the system will control on chip built-in self-test (BIST) engines collect and compress repair data, program fuses and finally decompress and reload the repair data for post fuse testing. In end use application this system decompresses and loads the repair data at power-up or at the request of the system.
摘要:
The invention provides a circuit that can observe data within shift registers without altering the data. The circuit includes selectors connected to the inputs and outputs of the shift registers. The selectors selectively connect the input with the output of a selected shift register to form a wiring loop for the selected shift register. A control device connected to the wiring loop uses the wiring loop to cause the data to be continually transferred from the output of the selected shift register to the input of the selected shift register and back through the selected shift register in a circular manner. The control device includes a counter used for determining the length of a selected shift register and a set of registers to store, for future use when rotating data in the shift registers, the length of each shift register. The control device also includes a data output accessible from outside the circuit. An observation wire is connected to the wiring loop, and the data passes from the wiring loop to the control device through the observation wire. The control device outputs data appearing on the wiring loop as the data is circulated through the selected shift register to permit data within the selected shift register to be observed outside the circuit without altering the data within the selected shift register.
摘要:
A system for and method of performing high speed memory diagnostics via built-in-self-test (BIST) is disclosed. In particular, a test system includes a tester for testing an integrated circuit that includes a BIST circuit and a test control circuit. The BIST circuit further includes a BIST engine and fail logic for testing an imbedded memory array. The test control circuit includes three binary up/down counters, a variable delay, and a comparator circuit. A method of performing high speed memory diagnostics via BIST includes, but is not limited to, presetting the counters of the test control circuit, presetting the variable delay to a value that is equal to the latency of the fail logic, setting the BIST cycle counter to decrement mode, presetting the variable delay to zero, re-executing the test algorithm and performing a second test operation of capturing the fail data, and performing a third test operation of transmitting the fail data to the tester.
摘要:
A design structure for a system for and method of performing high speed memory diagnostics via built-in-self-test (BIST) is disclosed. In particular, a test system includes a tester for testing an integrated circuit that includes a BIST circuit and a test control circuit. The BIST circuit further includes a BIST engine and fail logic for testing an imbedded memory array. The test control circuit includes three binary up/down counters, a variable delay, and a comparator circuit. A method of performing high speed memory diagnostics via BIST includes, but is not limited to, presetting the counters of the test control circuit, presetting the variable delay to a value that is equal to the latency of the fail logic, setting the BIST cycle counter to decrement mode, presetting the variable delay to zero, re-executing the test algorithm and performing a second test operation of capturing the fail data, and performing a third test operation of transmitting the fail data to the tester.
摘要:
A system and method for performing high speed memory diagnostics via built-in-self-test (BIST). A test system includes a tester for testing an integrated circuit that includes a BIST circuit and a test control circuit. The BIST circuit further includes a BIST engine and fail logic for testing an imbedded memory array. The test control circuit includes three binary up/down counters, a variable delay, and a comparator circuit. A method includes presetting the counters of the test control circuit, presetting the variable delay to a value that is equal to the latency of the fail logic, setting the BIST cycle counter to decrement mode, presetting the variable delay to zero, re-executing the test algorithm, performing a second test operation of capturing the fail data, and performing a third test operation of transmitting the fail data to the tester.
摘要:
A design structure for a system for and method of performing high speed memory diagnostics via built-in-self-test (BIST) is disclosed. In particular, a test system includes a tester for testing an integrated circuit that includes a BIST circuit and a test control circuit. The BIST circuit further includes a BIST engine and fail logic for testing an imbedded memory array. The test control circuit includes three binary up/down counters, a variable delay, and a comparator circuit. A method of performing high speed memory diagnostics via BIST includes, but is not limited to, presetting the counters of the test control circuit, presetting the variable delay to a value that is equal to the latency of the fail logic, setting the BIST cycle counter to decrement mode, presetting the variable delay to zero, re-executing the test algorithm and performing a second test operation of capturing the fail data, and performing a third test operation of transmitting the fail data to the tester.
摘要:
A method and system for testing an embedded DRAM that includes DRAM blocks. The method including: generating a test data pattern in a processor based BIST system, for each DRAM block, performing a write of the test data pattern into the DRAM block, performing a pause for a predetermined period of time, and performing a read of a resulting data pattern from the DRAM block; where for each DRAM block, the write of the test data pattern into the DRAM block is performed before the pause, and the read of the resulting data pattern from each DRAM block is performed after the pause; where at least a portion of the pause of two or more of the DRAM blocks overlap in time; and for each DRAM block comparing the test data pattern to the resulting data pattern.
摘要:
Wafer test and burn-in is accomplished with state machine or programmable test engines located on the wafer being tested. Each test engine requires less than 10 connections and each test engine can be connected to a plurality of chips, such as a row or a column of chips on the wafer. Thus, the number of pads of the wafer that must be connected for test is substantially reduced while a large degree of parallel testing is still provided. The test engines also permit on-wafer allocation of redundancy in parallel so that failing chips can be repaired after burn-in is complete. In addition, the programmable test engines can have their code altered so test programs can be modified to account for new information after the wafer has been fabricated. The test engines are used during burn-in to provide high frequency write signals to DRAM arrays that provide a higher effective voltage to the arrays, lowering the time required for burn-in. Connections to the wafer and between test engines and chips are provided along a membrane attached to the wafer. Membrane connectors can be formed or opened after the membrane is connected to the wafer so shorted chips can be disconnected. Preferably the membrane remains on the wafer after test, burn-in and dicing to provide a chip scale package. Thus, the very high cost of TCE matched materials, such as glass ceramic contactors, for wafer burn-in is avoided while providing benefit beyond test and burn-in for packaging.