Patent ID: 6174738
Filing Date: 2001-01-16
Classification: H01L

Abstract:
A method of determining an accurate disposition decision for each inspected layer of a wafer selected from a wafer lot in a semiconductor manufacturing process, the method comprising:(a) determining a defect density f in a layer n of the wafer selected from a wafer lot;(b) determining a ratio a/A wherein a is calculated for each defect size by multiplying an overlap value by the combined length of structures in a die that have an overlap value for each size defect and wherein A is the total area of the die;(c) determining a value .alpha. by integrating (a/A)f.intg.(d) as a function of d, the size of defects in layer n, from 0 to infinity where .alpha. is the layer layout sensitivity;(d) determining a yield value Y.sub.n for layer n from the relationship:1-((accumulated cost for a die in layer n)/total cost of die))risk factor;(e) calculating a disposition criterion from the equation:Y.sub.n =e.sup.-.alpha.A(disposition criterion);(f) comparing the defect density in layer n with the calculated disposition criterion for layer n;(g) placing the wafer lot on hold if the defect density in layer n is above the calculated disposition criterion for layer n; and(h) sending the wafer lot to the next process if the defect density in layer n is at or below the calculated disposition criterion for layer n.