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#analog-design
Title
# analog-design
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Boris Murmann

05/04/2021, 11:34 PM
They do. You need equal metal coverage to get the same Vt, etc.
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Tom

05/07/2021, 8:22 PM
@Boris Murmann, why does metal coverage effect Vt? is it because it alters the shape of the electric field?
@Tim Edwards do you know the answer to my question above?
And a follow up question is - If I have a good covering of M2 over the gates which is also uniform then will less uniform routing on M3 above have much of an impact?
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Boris Murmann

05/08/2021, 10:16 PM
Metal coverage affects the temperature profile during processing, as well as the strain/stress profile. The effect is not related to electric fields.
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Tom

05/08/2021, 10:16 PM
Ah i see thanks, so metal on any layer has an impact?
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Boris Murmann

05/08/2021, 10:18 PM
I don't think M3 matters much when you have M2 coverage. You can see that higher layers don't matter that much in general from the paper that I linked in an earlier post.
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Tom

05/08/2021, 10:19 PM
interesting thank you, @Boris Murmann