A Built-In Self-Repair Scheme for NOR-Type Flash Memory

The strong demand of non-volatile memory for SOC and SIP applications has made flash memory increasingly important. However, deep submicron defects and process uncertainties are causing yield loss of memory products. To solve the yield issue, built-in self-repair (BISR) is widely believed to be cost effective. It is, however, non-trivial to implement BISR on flash memories. In this paper we propose a BISR scheme for NOR-type flash memory. The BISR scheme performs built-in selftest (BIST), built-in redundancy analysis (BIRA), as well as on-chip repair. A typical redundancy architecture for NOR-type flash memory is assumed, based on which we present a redundancy analysis (RA) algorithm. Experimental result shows that the proposed BISR scheme can effectively repair most defective memories.