Although multiple scan chains can effectively decrease test time and reduce the test data, it requires more input channels so that the test cost is increased. To solve the problem, a grafting mechanism with multiple scan chains is proposed, which generates base vectors using a dislocation method in order to merge as many driving ends as possible based on correlation in the test vector. Experimental results show that the proposed
scheme uses fewer channels for the test data input and provides a higher compression ratio while maintaining high-speed testing for multiple scan chains.