Replies to post #1224 on Advanced Micro Devices Inc (AMD)

[Elmer Phud]

Spokeshave -

The ones I referenced, and others, are directly related to problems with masks, number of layers and other things that accompany a new die design.

But there are other designs and steppings running on the same process. They have masks too and use the same number of layers and all must follow the same design rules defined for that process. The size of metal lines must meet the requirements for the current they carry. The spacing between lines, and a whole host of rules that I'm not up on are process specific, not design specific. Sure sometimes the design can be faulty, even if it's bug free, because of process issues that need to be accounted for, but that design would never go into production so only a small number of wafers would be wasted. This could very easily apply to Athlon64 but it would apply to Opteron as well. One of the rules for releasing a process into production is usually demonstrating it can run in volume at a defined defect density level. Maybe SOI hasn't demonstrated that ability yet?

There are three relatively new products that are either in production or tooling for production - Barton, Opteron and A64. Each is a new die design and each will have a greater design-related defect density than they will at the end of their production life.

The defect types you described are obscure and not a significant contributor to yield loss once a process is in volume production. They are the kinds of problems that are worked out before a process is considered "manufacturable". In 20 years I have never heard anyone mention "design related defect density". I don't even know what you are trying to say. Intel runs several products on their .13u process. P3, P4, Banias, and soon Itanium (if not already) and their yields match predicted levels based solely on die size and the defect density for the process. There is no such thing as a design specific defect density. I have worked with other foundries and the same rule applies. Tell me the die size, the current defect density for the process and I'll tell you the yield you should expect. I never need to know the design. The yield calculator I gave a link to didn't ask you what design it was did it?

[j3pflynn]

spokeshave, one apparent correction. According to Johan, Opteron and A64 are the same thing, just with HT links disabled. So, they're not really 2 separate products, just a different final(?) step.
Paul