assura LVS parameter mismatch

[aeaglan]

I'm coming across the following errors when i run LVS on assura on my design. Can anyone help me with it? thank you for your help in advance!

====== Parameter Mismatches for Instances =====================================

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = (param 1)
Schematic Instance: R1 resnsnpoly
Layout Instance: avD22_1 resnsnpoly

Err: Sch RES missing params: w ; Lay RES L/W/m 0.00018 1.5e-06 1
Layout Instance is the merged result of: avD22_1 avD22_2

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = (param 2)
Schematic Instance: R0 resnsnpoly
Layout Instance: avD22_3 resnsnpoly

Err: Sch RES missing params: w ; Lay RES L/W/m 0.00018 1.5e-06 1
Layout Instance is the merged result of: avD22_3 avD22_4

===============================================================[Diff_Pair_v3.2]
====== Summary of Errors ======================================================
===============================================================================

Schematic Layout Error Type
--------- ------ ----------
2 2 Parameter Mismatches for Instances

 

[erikl]

You should post the corresponding detail(s) from schematic and layout!

 

[cop02ia]

Hi,

Err: Sch RES missing params: w ; Lay RES L/W/m 0.00018 1.5e-06 1
Layout Instance is the merged result of: avD22_1 avD22_2

It looks like your schematic does not have "w" parameter definitions.
I'm guessing either that you did not define the parameter values in your device (I wonder if this can pass Virtuoso's 'Check & Save' - if you are using Cadence layout tools)
OR your device CDF (again, if you are using Cadence tools, but then, you are using Assura, right?) simulation properties is not defining the "w" parameter.

So... does your device in the schematic have values for 'w'?

I-FAB

 

[xplorin]

Hi,

You might have missed out some connections in either layout or schematic. Width is not matching since your description says that layout has two instances of that resistor while schematic has only one instance. So in layout W is the cumulative of both instances. You might have messed up some net connections.

 

[cop02ia]

Hi,

There seems to be no short /open error, so, IMO, it most probably is not due to wrong connections.
If the parameter values mismatch, I suspect it is due to the merging parallel/serial values.

However, in this case it states:

Err: Sch RES missing params: w

That's why I suspect the device's parameter for simulation definition is the problem.
Please check/dump the CDF (Component Description Format is Cadence speak - I don't know the equivalent for it in other tools).

I-FAB

 

[xplorin]

Yupp did u find any merging parallel or series connections. From the lvs debug you can zoom into that layout portion, and see if there is any merged connections. This is the only possibility I can think of.

 

[cop02ia]

It says "missing parameter" not "incorrect/wrong parameter value".
There are 4 devices merged into 2 as it says in the report - so it's either serial or parallel.

Nevertheless, the issue is missing parameter.

I-FAB