What are the steps for Diva LVS?

diva lvs

who can tell me the step about diva lvs ,I am a new man .
I study it by myself,but there is some question I can not solve.

step 1:I get the extracted view of the layout
step 2:I complete the lvs form and try to run lvs
but it failed,so I use the default,it start to run,but the erro in the extracted view of the layout is not as same as the erro in the schematic

Now I do not know whether the step is right .who can tell me ??

thanks!!!

Re: The problem of diva lvs

I think your steps are right.
The LVS results in layout may be some different with your schematic.

The problem of diva lvs

but the erro in the layout doesn't match for the erro in the schematic
I want to know if it is the question about the port
but I don't know how to set up the port

The problem of diva lvs

who can help me ?
thanks!!!

Re: The problem of diva lvs

wjlzhx said:

but the erro in the layout doesn't match for the erro in the schematic
I want to know if it is the question about the port
but I don't know how to set up the port

Click to expand...

What do you mean by "match" here?
Do you have an LVS rule file?

The problem of diva lvs

U should find these unmatched error. some error is not as same as the specification. ur steps r right.

Re: The problem of diva lvs

the number of ers in extracted and schematic will be different.
As an example - you have 1 MOS device in schematic with Wtotal=100 and with 4 fingers. In layout it means 1 device but extract sees it as 4 independent devices.
Depending how the LVS deck is written it will "collapse" those 4 into one and match it with schematic or it could require 4 devices in schematic.
Anyway what you would be able to see is 4 instances in extract errorl log and 1 in schematic one.
It should also prune (remove) unused devices. If it does not work correctly you would have to draw every unused device in schematic.

My personal experience is to match all devices first (down to about 4 unmatched) before you even try to look at nets since usually VDD/VEE nets highlight whole layout and you will not see anything anyway.

The problem of diva lvs

can you describe you question in detail?
detail log file ?