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Dipankar

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Posts: 59

MIM layout queries
Jun 05^th, 2009, 10:25am

Dear All,

Need your help regarding following queries .

q1. Is it a strict "NO" to run any metal layer below MIM? (In my case MIM is between m6 and m5)

q2. If the answer to q1. is yes then is it safe to define dummy blockage layer on the top of mim to protect that area from dummy insertion by Foundry ?

q3. Is providing some shielding layer beneath MIM is necessary ? If yes then which layer ? N-well ? plz suggest ?

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With Thanks and Regards,
Dipankar.

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ywguo

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Posts: 943
Shanghai, PRC

Re: MIM layout queries
Reply #1 - Jun 16^th, 2009, 7:43pm

Quote:

q1. Is it a strict "NO" to run any metal layer below MIM? (In my case MIM is between m6 and m5)

It is a strict "NO".

Quote:

q2. If the answer to q1. is yes then is it safe to define dummy blockage layer on the top of mim to protect that area from dummy insertion by Foundry ?

Yes.

Quote:

q3. Is providing some shielding layer beneath MIM is necessary ? If yes then which layer ? N-well ? plz suggest ?

No.

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Dipankar Community Member Offline Posts: 59	Re: MIM layout queries Reply #2 - Jun 20^th, 2009, 5:54am Dear Sir, Can you please illustrate why running any other metal line beneath MIM is not a good practice ? Actually I have m1 routing at some places beneath MIM (it's between m6 and m5) and it does not violate drc.
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Berti

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Posts: 356

Re: MIM layout queries
Reply #3 - Jun 23^rd, 2009, 3:42am

I think it is ok to route metal lines underneath a MIM capacitors, if you can except the increased bottom plate capacitance and risk of coupling.
But q3 was referring to shielding what you can do, but is not necessary.

The use of M5/M6 below the MIM is probability prohibited by the fab since it might results in a short in fabrication.

Regards

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Colbhaidh New Member Offline Posts: 6 Scotland	Re: MIM layout queries Reply #4 - Jul 21^st, 2009, 4:23am The is no Fab process limitation to routing metal beneath the bottom plate. The only concern would be coupling as mentioned before.
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