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Politics : Formerly About Advanced Micro Devices -- Ignore unavailable to you. Want to Upgrade?


To: Zoran who wrote (79993)11/16/1999 4:02:00 AM
From: Process Boy  Respond to of 1579697
 
Zoran - <I saw some cross sections of notched gates. Some look really great but one can easily find transistors with a notch only on one side. Everything from the same die.>

Intel device?

PB



To: Zoran who wrote (79993)11/16/1999 1:55:00 PM
From: Shane Geary  Read Replies (1) | Respond to of 1579697
 
Zoran: Re" Intel has a disadvantage of not being able to apply any kind of advanced process control since they cannot know what the real width of the notched gate is."

There are a few ways of doing it. The most elegant is to use the new CD-AFMs (Atomic Force Microscopes) which can measure re-entrant profiles and are beginning to appear.

I suppose that you could also use a full-wafer FIB (focussed ion beam) tool to mill across a test structure and measure the CD from the cross-section. You get a big nasty hole in your substrate though, and I'd also be worried about contamination.

In any case, as WATSONYOUTH has stated, there will be a trade-off between using this method (or similar) and doing the thing properly (from my point of view!) with lithography. I'm sure Intel has compared the relative process variation (although I don't know how they got enough data points for the notched method. Go PB, tell us).

Things that have been tried in the past (like printing the resist lines and doing an isotropic O2 plasma flash to take some of the resist off and thereby shrink the CD for the same pitch) haven't made it into the mainstream.

I agree with you that it would be desirable to measure the base width top down.

Keep up the interesting posts!

Regards,

Shane