Advanced Micro Devices Inc (AMD)

[alan81]

When the process is brand new, you can think of every lot as a rocket lot, but the TPT is not going to be the 9 days that Semi was talking about... Because the equipment would not be so highly tuned and people trained on it as they are later in the development cycle. The fast rocket lots in general are used to checkout new designs on a fairly healthy process. The very first run on a new process can take a very long time to come out just due to equipment issues, training issues, and other factory logistic issues. It is not a highly tuned machine yet!

In terms of doing development now... absolutely a requirement. Some equipment vendors will loan you stuff, or even have a small clean room where you can process wafers. You can think of the process as a sequence of steps, and you can check out each step somewhat independently. You would run material at that step and then take some physical measurements to see if the result match what you were getting on 200mm wafers. Once each step is checked out and believed to match what you got on the 200mm wafers you would then start the full loop runs through the entire factory. This is when it starts getting both interesting and exciting, as you just might get functional high yielding material, or more likely you get junk and spend time figuring out why.
Worst of all, you may find problems during long term reliability tests months after the first material is out... and those problems may require changes at the very beginning ot the cycle, and another round of long term reliability testing to validate. There is a fair amount of risk in the schedule at the start, especially if you are counting on very few information turns.
As an analogy you can think of it as a big software project. You would compile each module seperately and check it out. At some point, each module is believed to be clean, so you do the "big" compile with everything together and see what you get. The first of these compiles could take three months or so before you can start running the program to see if it has any bugs in it. Once you have the program compiled and running, there is still lots of work to do to make sure it works properly and bug free. Every time you find a bug and fix it, you need another 3 month compile... or perhaps you can get a rocket lot and get the results in 2 weeks
You can imagine it would take quite some time to get the program up to production requirements.
--Alan