assura lvs problem in ibm 90nm pdk

Hi iamlearning

Thank you for the clear problem description. : )  Would you please provide the following info using Assura32?

a. Open up LVS form
b. Press "Netlisting Options" button
c. What is written in "view list" and "stop list"? Is it "auLvs schematic symbol" and "auLvs"?

If yes, would you please check if an "auLvs" view is present for cells mimcap and inductor?

Thanks
Quek

Sorry for the delayed Feedback. "view list" and "stop list" of the "Netlisting Options" are "auLvs schematic symbol" and "auLvs" respectively and there is no "auLvs" view for the mimcap and inductor cells, olnly shcematic, layout, symbol and auCdl views. So, may be you knocked right :) . I also noticed that, there is "auLvs" view for the 'nfet', but not for 'nfet_rf'. Still, I could complete the LVS of an inverter consisting of 'nfet_rf'. Moreover, lvs of the mimcap and inductor can be performed by assura317 with the same "view list" and "stop list" in the "Netlisting Options"  and with no "auLvs" view of them.

Would you please write me what can I do in this situation? Thank you for your tips :)

Regards ..

Hi iamlearning

Does "nfet_rf" has a schematic view which consists of other primitive devices? E.g. If you open up the schematic view of nfet_rf (if it exists), does it show an nfet device with a few diodes?

Would you please copy the symbol view of mimcap and renamed it as auLvs? Now re-run lvs and see if it works. I am not sure why Assura317 has no problem. This would be a little hard to guess unless I have the testcase.

Best regards
Quek

schematic view of the nfet_rf is nothing special. It is same as the symbol of the nfet, but difference is- it is surrounded by a green circle. No other device symbols like diode,resistor or capacitor are included. Probably the symbol is different from the 8rf. However, the model of the nfet_rf uses the model of nfet, this is for sure.

Shall I rename the copied symbol of mimcap to 'auLvs' or the view type is to be changed anyway? I am not clear because, if I have a symbol named auLvs derived from the mimcap with view type 'symbol', then what will happen when I shall try the same for the inductor? Shall not I attempt to have a couple of 'auLvs' with the view type- 'symbol'?

Thank You for your suggestions :)

Best Regards ...

Hi iamlearning

This explains why there is no problem for nfet_rf. It has a schematic view and so Assura netlister descends into this view when it encounters nfet_rf device. In this view, it find nfet device that has auLvs view and so it stops and writes the info to the netlist. You simply need to copy the "symbol" view and change its name to "auLvs". Please do the same for the inductor too.

In library manager, select "symbol" view of mimcap/inductor and do a right mouse click. Select "Copy" and enter "auLvs" as the new view name. There is no need to change your schematic.

Best regards
Quek

Today, I opened the symbol view of the mimcap and followed: symbol editor window->file->save a copy-> then saved as view name 'auLvs' instead of 'symbol' with the library and the cell name unchanged and the LVS advanced. Thank you Quek for the right instructions.

However, the LVS was not complete due to a new error. The error in the lvs log file appears as: 

Error: rootCell(or ?cellName) - cell 'caps layout components' from the layout does not bind to anything in the schematic.

where, the caps and the components are the names of my cell and the library respectively. I never encountered this error with assura317 before.

Can you please give me any idea what could be the possible solution for this problem?

Thank You,
Best Regards...

Hi iamlearning

Please ensure that the top cell names of your schematic and layout are correct. E.g. if you are using a schematic and layout named "ABC", then you should use "ABC" as the top cell names in the lvs form. The message is informing you that either your layout or your schematic top cell name is not correct.

Best regards
Quek

Thank you Quek for your reply. But, both of my layout and schematic cells are named as 'caps' and the shcematic and layout 'cell name' fields of the lvs form are filled with this name. The library names are also same, the only difference is the 'view' fields of the lvs form- one is 'schematic' and another is 'layout'.

I have another strange observation. This error did not appear when I checked lvs by assura317 first time. Then I checked the lvs again with assura32 and with the lvs form untouched. This error came that time. Next, I ran lvs once more with assura317 and with the lvs form still untouched, but strangely, this error appeared then. I followed these three steps for another cell and the story is exactly same. So, now I am getting this error both with assura317 and with assura32, whereas assura317 worked well previously.

This seems strange to me ! Can you guess anything in it?

Thank You,

Best Regards

Would you please upload the rsf and log files for lvs run using Assura32?