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#analog-design
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# analog-design
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Paul Schulz

08/21/2020, 2:44 AM
@User What's the metal used in the process? (metal1) Is it Al?
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Tim Edwards

08/21/2020, 12:58 PM
Aluminum for m1 through m5, with a Titanium Nitride (TiN) layer for "local interconnect" (under metal1) and a Copper RDL layer (done by a 3rd party service, so the specs we currently have for RDL need to be revisited).
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Trevor Clarke

08/21/2020, 3:48 PM
Speaking of the local interconnect. Can it be treated as just another metal layer or is it truly cell local only? If the second, what's the max effective length?
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Tim Edwards

08/21/2020, 5:29 PM
There is a weird and hard-to-implement DRC rule that restricts uncontacted local interconnect to an aspect ratio of 10:1. Possibly you can get around that rule by specifically declaring the local interconnect to be a resistor. Regardless, any long wire of local interconnect should be treated much the same way as you would a long wire of polysilicon: Something to avoid unless you're okay with a high resistance. TiN has a resistivity that is about 1/3 of polysilicon, but that's many times more than the resistivity of any metal layer.