ON THE REPAIR OF DEFECTIVE FIELD PROGRAMMABLE LOGIC ARRAYS TO INCREASE YIELD.

Newly manufactured field programmable logic arrays (FPLAs) often contain crosspoint defects. Due to the inherent sparsity (absence of devices at crosspoints) of PLAs, it is highly probable that certain types of faults within the unprogrammed FPLAs can be masked out without any additional hardware, leading to the reclamation of the previously discarded chips. The authors discuss a technique for locating the faults within an unprogrammed FPLA and present a novel method for programming the FPLA around these faults. The approach differs from previous methods in that the programming is formulated as a matrix problem to obtain a polynomial-time solution. Computer studies have shown that even FPLAs with large number of defects can successfully be repaired, thereby increasing the yield.