Test modification and compression technique for reducing total test volume with dictionary data

Though a number of techniques for test data compression have been proposed until now, most of them have not taken into consideration the volume of dictionary data that specify decompression rules. This paper presents a test modification and compression technique for reducing total test volume including dictionary data. As for most test compression techniques such as Huffman coding based methods, if we determine the block size large, it results in small test volume but large dictionary volume. Therefore, it has been thought that large block sizes are ineffective for total test data volume reduction. However, if dictionary volume can be greatly reduced, large block sizes can be more effective. This paper describes a compression method for reducing total test volume, especially dictionary volume, by using a technique that produces a test set for which the number of code words is small in the case of a large block size. The effectiveness of the proposed method is shown through test data compression experiments for ISCAS '89 benchmark circuits.