ted, re:<chips per wafer>
I'm still catching up on posts from the last day or so, but noticed no one really answered your question about how many Athlons can be expected from each wafer.
The math is really pretty simple. 8" wafers have a useable radius of 10cm, therefore their area pi-r-squared is about 31,400 cm sqared.
The die size of the Athlon is something like 104 sq. mm -- I think it was one-sixty-something in 0.25µ process.
Using 104 sq. mm, we get 302 die per wafer.
However, since there is waste space around each CPU and waste space around the edge of the round wafer, you have to subtract 10-20% (process guys would know the exact formula for waste space).
That leaves 240 Athlons per wafer if the yield was 100%.
I would be ecstatic if AMD had 50% yield already on the 0.18 process. There are other reasons that production does not equal the anticipated value, such as packaging failures, SRAM or PC board failures, entire wafers are sometimes bad or get wrecked,etc.
Remember also that, for most of Q4's output, the die size was 16X mm, with maybe only 40-50 good Athlons out of 150 per wafer.
Petz |
