Test Data Reduction for BIST-Aided Scan Test Using Compatible Flip-Flops and Shifting Inverter Code

In this paper, a method for reducing test data volume of BIST-aided scan test (BAST) is proposed. In our BAST method, scan chains are ordered using compatible flip-flops to reduce the conflicting bits between ATPG pattern and random pattern obtained by LFSR. The inverter block in BIST-aided scan architecture is modified for shifting inverter code such that the random pattern produced by LFSR has less conflicting bits with ATPG patterns when providing the test pattern to the scan chains. The experimental results show the method can reduce the test data volume than the previous method.