Critical area cost disposition feedback system

Abstract

A method of determining an accurate disposition decision for each inspected layer in a wafer lot wherein a measured defect density is compared to a calculated disposition criterion determined for each inspected layer. If the measured defect density is above the calculated disposition criterion the wafer lot is placed on hold and if the measured defect density is at or below the calculated disposition criterion the wafer lot is sent to the next process. The disposition criterion for each layer is determined from a yield value determined for each layer. The yield value is the yield necessary for each layer to obtain a profitable product and is determined from cost data for each die in the wafer lot and a risk factor determined by management and includes market data such as selling price and demand for the product. The yield value is combined with defect sensitivity determined for each layer. The defect sensitivity is determined from the combination of critical area and historical frequency for each layer.