Consider a chip design with eight mask level processes with

Consider a chip design with eight mask level processes with a chip area of 0.5 cm2. The average fatal density per cm2 is 0.1 for four levels, 0.25 for two levels, and 1.0 for two levels; calculate the final yield for the process.

Solution

Yield Y=1/(1+AD)^N

Where A:Chip Area ; D:Fatal density per cm²    ; N:Complexity level

(i)

For D=0.1 per cm²

A=0.5 cm²   N=4 as four level

Y1 = 1/(1+0.5*0.1)⁴ =0.823 ..........(1)

ii)

For D=0.25 per cm²

A=0.5 cm²   N=2 as two level

Y2 = 1/(1+0.5*0.25)² =0.79 ..........(2)

iii)

For D=1.0 per cm²

A=0.5 cm²   N=2 as two level

Y3 = 1/(1+0.5*1)² =0.44 ..........(3)

Final yield Y=(Y1+Y2+Y3)/3

Y=(0.823+0.79+0.44)/3 =0.684 [answer]