What is meant by "symbolic" view in cadence?

[varma_cs012]

Folks,

I am working with cadence virtuoso layout editor. When I am using contact types, I am seeing that they are not made by pcell layout but they are done in different view name called "symbolic".

Can anybody please tell me what is this view and why it is used?

if possible give me some difference between a pcell layout and symbolic!

Please reply back if you don't understand the question at all!

thanks in advance,
varma.

 

[varunmjman]

Did u mean abstract view??

I couldnt understand ur question..

 

[varma_cs012]

Ok, I myself found some answer!

"A symbolic device is an instance of a parameterized cell that has been defined in the technology file." from Virtuoso® Layout Editor User Guide

Please share if anybody has any more information.

I am more interested to know about how it helps in Layout database management and etc.

Thanks,
Varma

Added after 1 minutes:

Did u mean abstract view??

I couldnt understand ur question..

Nope I mean "symbolic" view in Cadence virtuoso layout editor.

What is the use of this symbolic and why it is used for creating contact, rather than just using a pcell layout!

 

[erikl]

What is the use of this symbolic and why it is used for creating contact, rather than just using a pcell layout!

The contact and via layers usually take up the lion's share of data in the final GDSII file - each structure includes at least 1 contact or via, even more in the majority of cases.
So I guess their symbolic's view purpose is to reduce the amount of data in the layout data base: instead of keeping a couple of corner-point and layer data (3 layers, each) for each individual contact or via, their symbolic view just stores the center point and the link to the symbol - this will reduce the amount of data quite a lot.
Of course this could also be done using pcells, but this probably has a historic reason: symbolic views were already available long before pcells were. And pcells need to store their parametric properties, hence more data.