Patent ID: 6175938
Filing Date: 2001-01-16
Classification: G11C

Abstract:
A method for reducing extra standby current induced by process defects, comprising the steps of:(a) providing a plurality of wafers having thereon a plurality of SRAM chips having corresponding SRAM cells(b) testing SRAM cells of one of the SRAM chips on one of the plurality of wafers to identify and store addresses and locations of defective bit lines in the one of the SRAM chips for a subsequent repairing process, each SRAM cell having a plurality of pull-up transistors, fuses, and bit lines, wherein one of the fuses is positioned between each one of the plurality of pull-up transistors and the plurality of bit lines, respectively;(c) testing each SRAM chip on said one of the plurality of wafers using said testing step (b);(d) testing each one of the plurality of wafers using said testing steps (b) and (c);(e) repairing a defective bit line found in any one of said testing steps (b)-(d) by replacing each defective bit line with redundancy;(f) opening each fuse, of the plurality of fuses, corresponding to defective bit lines determined during any one of said testing steps (b)-(d); and(g) repeating said testing steps (b)-(d) to verify proper repair during said repairing step (e).