I am using Calibre 2006 for LVS/DRC with the Cadence tools IC 5.141USR4. I use Virtuoso Layout XL for layout wherever possible. I am doing a full custom analog/RF chip.

I have a cell called C, which has a schematic view called "schematic." C is used in two places on my chip. Due to a tight floorplan, the layout for these two places needs to be different. So I create two views "layout1" and "layout2" in cell C which both are layouts for "schematic". I now get "layout1" and "layout2" LVS clean using Calibre's flat LVS.

Now I want to move to the top level and use hierarchical LVS to verify the whole chip. Unfortunately, the hierarchical LVS only understands how to bind a view called "layout" to a view called "schematic." What is so special about the name "layout", and how can I add different view names like "layout1" and "layout2" to be bound to the same schematic so they can be verified with hierarchical LVS?

I am not sure whether the problem lies with the Calibre toolset or the Cadence database or in the way the two are integrated in the design flow. What is a good way to deal with this issue. We have this at many places in our chip due to our aggressive floorplan and special structures.

Thanks,
Setu

Hi Andrew,

First of all thanks a lot for your help! I am sure that I am echoing the views of many others on this forum that I have learnt a LOT from your posts.

I did place service requests with Mentor and Cadence about this.

Mentor says that Calibre LVS has no concept of a "view." Cadence says that for Assura, different layout views can be specified in the bind file as follows:

instance "cellName viewName library" " cellname viewName library"

Example

C1 "nand schematic stdLib" "nand2 layout1 stdLib"
C2 "nand schematic stdLib" "nand2 layout2 localLib"

But right now, I have to use Calibre.

So you are definitely right that the issue and the solution (if any) lies with the PIPO stream out - is there a deterministic way for naming different views to be streamed out of the same cell? Something like <cell name>_<view name>. The reason is that my PIPO log file is literally thousands of lines long and I cannot look through them all to figure out the cryptic names that are assigned to the different layout views. How does Assura manage to do this BTW?

What is the recommendation in general for situations where we need to have a single schematic and many different layouts? Should different cells (with perhaps only a layout view) be created for the different layout versions? Or should all the views be kept under the same cell name?

Thanks,
Setu