| 摘要 |
PURPOSE:To relieve the defects in most of the positions of the IC efficiently by a small redundancy by setting the changeover units of redundancy structure in the IC circuit in a hierarchal manner. CONSTITUTION:A first hierarchal block is changed into a redundancy by fundamental blocks 1S and redundancy blocks 1R, and a predetermined normal function of a second hierarchal block 2 is enabled. The same applies to the relationship of a second hierarchy and a third hierarchy. The units 1S, 1R of the circuit blocks of the first hierarchy are tested by informations 12 from a computer 8, flag informations 9 are generated 7, and buses 4 are detached on non-defect, and changeover informations 10 are generated 7 on defects. The defects of the circuit blocks of the second hierarchy are relieved through changeover operation regarding the circuit blocks of the first one, the block group 2 of the second one is changed over and operated 6 by using an OR circuit 13 and an inversion circuit 14, and probability in which the circuit blocks of the third hierarchy have defects is reduced remarkably. Since an additional circuit for a changeover can also be made contain in the block 2 of the second hierarchy, the system can cope with these defects, and a high-degree defect relief effect is obtained. |
