A defect-situation forecasting technology to optimize future DRAM-redundancy design

A method of forecasting defect situations in future DRAMs manufactured in the same or similar lines is demonstrated The estimated word-line defect situation of a 0.35 micron DRAM almost agreed with the actual data. By calculation with actual 0.5 micron DRAM word-line defect data, we approximated D(x), the function of particle-existing-probability density on a particle diameter x, as a proportion of 1/x/sup 1.5/. The word-line defect counts of a 0.35 micron DRAM were estimated by the product of the approximated D(x) and P/sub k/(x), the possibility function that k-lines of short or open circuits will be made.