MULTIPLE-CAPTURE DFT SYSTEM FOR DETECTING OR LOCATING CROSSING CLOCK-DOMAIN FAULTS DURING SCAN-TEST

摘要

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.

主权项

1. A method 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 or more capture clocks and one or more scan cells; said method comprising the steps of: (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 operation; (b) applying an ordered sequence of capture clock pulses to all said scan cells within said N clock domains during a capture operation, the ordered sequence of capture clock pulses comprising at least two capture clock pulses from two or more selected capture clocks, for controlling two or more clock domains, in a sequential order, wherein each said selected capture clock must contain at least one said capture clock pulse, and when detecting or locating selected delay faults within a clock domain, said selected capture clock controlling the clock domain contains at least two consecutive said capture clock pulses to launch the transition and capture the output response; and (c) analyzing output responses of all said scan cells to detect or locate said faults therein.