Use 1 gross die, 2 for net die and 3 for wafer yield

**Notes**

Use this form to calculate the gross die per wafer and net yield at
the wafer level. The required parameters for calculating the gross
die per wafer are the die size, the edge exclusion and the wafer
size. The die size is the stepping distance on the wafer and not
the size of the die after saw. If the sawn die size is known, add
the saw alley width to calculate the die size. The edge exclusion
is the region in the outer edges of the wafer that are left vacant
to allow handling and to allow sealing of the wafer in the etch
fixture for KOH etch or DRIE. It is usually around 5mm for KOH
etched wafers while for DRIE etched wafer it is higher. The
estimated die number does not include the area left out for
including alignment targets or test sites. Also based on the die
layout and how well the available wafer area is used, the die
number may vary.

Based on the defect size and the area of the die, the wafer level yield can be estimated using the probability theory. Based on the estimated yield the net die per wafer is calculated.

The plot shows the dependence of the percentage yield on the size of the die for a given defect density. It shows that when the area of the die increases the yield that can be expected out of a wafer drops for a given defect density.

-The area lost to alignment marks, test sites and ECE contact are not included in the calculation of die number.

-Optimum utilization of the wafer area is assumed in the die layout.

-The estimated yield is based on the probability of defect distribution and is approximate.

-The yield is at the wafer level, there may be a further drop in yield after packaging.

Data analysis > Die calculator