a silicon foundry produced 12 million 8-inch

Question

A silicon foundry produced 1.2 million 8-inch wafers in 1997; how many 600 mil die is that?  The foundry is scheduled to produce 20,000 12-inch wafers per month by the year 2001 using a 0.25 micronmeter process.

If a 16Mb SRAM yields 850 good die per 12-inch wafer and there are 1300 die per wafer, what is the yield and the die size?  If the SRAM cell size is 2 micronmeter² what fraction of the die is used by the cells and what is the cost per bit if the wafer cost is $3,000?  A 64Mb DRAM uses the same fabline on a 25mm² die; calculate the cost per bit for DRAM assuming the same yield.