Importance

Loading Importance Indicators...

Abstract

The redundancy circuit device includes a main word line 1 for selecting a first memory area and a subsidiary word line 2, and a spare subsidiary word line 4 for selecting a second memory area (in which spare memory cells are arranged). In case a defective memory cell exists in the first memory cell area, the address is programmed by a redundancy program circuit 14 of a redundancy circuit 41 (provided for each section) of a section decoder 42. Further, when a row partial signal outputted from a row partial decoder 13 hits a defective memory cell, the spare subsidiary word line 4 is selected through the redundancy program circuit 14 to select the spare memory cell, without selecting the subsidiary word line 2. In a memory device of double word line system, a defective memory cell can be replaced with a spare memory cell in unit of each of a plurality of the subsidiary word lines connected to the main word line, thus improving the redundancy efficiency and thereby increasing the production yield of the memory chip.

Loading the Abstract Image...

First Claim