A manufacturing facility has a yield that is controlled purely by random defects. The density of these random defects depends on the design rule used. More specifically, for a 1-µm design rule, the density is 0.5/cm², while for a 0.5-µm design rule, the density is 2.0/cm². (Use the Poisson yield model.)

(a) A given product takes 1.0 cm². Further, 90% of this area is using 1 µm design rules, while the rest 10% is using the 0.5 µm design rules. Estimate the yield of this product.

(b) This product can be redesigned (shrunk) to take only 0.5 cm2, but now 50% of the chip is using the 0.5 µm design rules. Estimate the yield of the redesigned product.

(c) What would be the ratio of good die per wafer of the redesigned product to that of the original product?