Page 117 - A Practical Guide from Design Planning to Manufacturing

90 Chapter Three

TABLE 3-6 Examples of Mainstream Product Costs
Assumptions Calculations
Die area 140 mm 2
Wafer diameter 200 mm Die per wafer 186
Defect density 0.5 cm −2
Process complexity (a) 4
Wafer yield 95% Die yield 50%
Processed wafer cost $3000 Die cost $33
Base package cost $10
Cost per pin $0.01
Number pins 500 Package cost $15
Test time 30 s
Test cost per hour $400/h Test cost $3
Test yield 95% Processor cost $54

Assuming typical values we can calculate the product cost of the ITRS
mainstream and server die sizes, as shown in Tables 3-6 and 3-7.
Calculating the percentage of different costs from these two examples
gives a sense of the typical contributions to overall processor cost.
Table 3-8 shows that the relative contributions to cost can be very dif-
ferent from one processor to another. Server products will tend to be
dominated by the cost of the die itself, but for mainstream processors
and especially value products, the cost of packaging, assembly, and test
cannot be overlooked. These added costs mean that design changes that
grow the die size do not always increase the total processor cost. Die
growth that allows for simpler packaging or testing can ultimately
reduce costs.
Whether a particular processor cost is reasonable depends of course
on the price of the final product the processor will be used in. In 2001,

TABLE 3-7 Examples of Server Product Costs

Assumptions Calculations
Die area 310 mm 2
Wafer diameter 200 mm Die per wafer 76
Defect density 0.5 cm −2
Process complexity (a) 4
Wafer yield 95% Die yield 25%
Processed wafer cost $3000 Die cost $158
Base package cost $15
Cost per pin $0.01
Number pins 1000 Package cost $25
Test time 45 s
Test cost per hour $400/h Test cost $5
Test yield 95% Process cost $198