[SI-LIST] Re: DC Resistance calculation in 2.5D solver
- From: Istvan Novak <istvan.novak@xxxxxxxxxxx>
- To: emcesd@xxxxxxx
- Date: Wed, 16 May 2012 08:40:41 -0400
Hi,
I wont comment on the specific tools, but will give you some generic ideas.
We many times dont realize that DC resistance calculations can be almost
as tricky as the high-frequency computations. We usually assume
(wrongly) that at DC the current density is uniform in the conductor
cross section, but except of a few hypothetical cases, it is not. This
is why, even at DC, the correct answer needs careful volume meshing, to
make sure that the different current density values are captured
properly throughout the conductor volume, including the end connections
leading to the observation points. Most tools have knobs for you to
turn on some of the key parameters (you may be surprised to see that
once you start turning those knobs, you get different answers from the
same tool to the same DUT).
So when you compare results from different tools, you may want to check:
- how the meshing is done and get them as close to be similar/same as
possible
- how the connection is assumed
For this second item, one hint: we can not use point connection, because
for zero cross section area the current density and the equivalent
resistance would be infinite: we have to use finite connecting cross
section area. So first you have to find out how the connections are
assumed in the two tools and then make sure that they are as
close/similar as possible. If these key elements are the same or close,
we can then expect similar results.
Regards,
Istvan Novak
Oracle
On 5/16/2012 7:52 AM, Tesla wrote:
> Hi, Experts
> In 2.5 field solver(eg: Sigrity or SIwave), if i want to get DC resistance of
> interconnect, i use the two method:
>
> 1 Use FEM to calcute from DC to Fmax Hz, use the DC s parameter to get the S
> parameter
>
> 2 Use IR drop in the analysis to get the DC resistance
>
> but the two method give two different DC resistance value, Which one i should
> trust?
>
> Thanks.
>
>
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