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Technology Stocks : Advanced Micro Devices - Moderated (AMD) -- Ignore unavailable to you. Want to Upgrade?

To: ptanner who wrote (44337)	6/14/2001 3:23:47 PM
From: dale_laroy	Read Replies (1) \| Respond to of 275872

>but I wonder if the square of die size for yield is appropriate or if it should be a something closer to the actual die size< Actually, it is more accurate to take the square of the percentage yield as die size doubles. So if one gets an 80% yield at one die size, doubling the die size would reduce percentage yield to 64%. Thus the actual yield in number of good die per wafer would decrease by about 60%.

To: ptanner who wrote (44337)	6/15/2001 3:25:58 PM
From: Petz	Respond to of 275872

You are all forgetting that when AMD built K6-2's at high yield in Fab 25 they were also building K6-3's at very low yield. Who knows how much capacity was wasted trying to build that blasted part. And saying that the yield automatically squares as the die size doubles is 1) only true when comparing CPU's made using the same process 2) is only true for the part of yield having to do with defect density. I think the best way to estimate Fab 25's and Fab 30's full capacity is to take FudgeWPW13*31400/DieSize where WPW is 5500 for Fab 25, 5000 for Fab 30 Fudge is about 45 to 60% depending on die size. It has to account for edge loss (10-15% depending on die size), yield (60-75% depending on die size) and Fab "down" time. Petz