Fluid Guardring Questions

 Hi Dan,

I don't know about installing FGR (Fluid GuardRing) outside of the techlib, but one thing that you can try is to create your own library and reference the technology library (this is an "ITDB" set up, Incremental Technology DataBase), then you will have write access to your part of the technology "graph" without modifying or otherwise affecting the 'master' technology that you reference. In my simple test, here's what I did in order to be able to add a Fluid GuardRing while referencing the "gpdk" library that is shipped with the tools installation. I created a very simple technology file (say FGR.tf) and compiled this when I created my library:

controls(


  refTechLibs(
    "gpdk"
  )


) ;controls

 This way I can add to the technology without needing write access to the base technology.

Hopefully this can get you started?

Regards,

Lawrence.

 Thanks Lawrence,

I created a separate techfile and brought it in.  I attached it to the existing work library and was able to define my own guardring in the database and make guardrings, polygons, etc.  Woot!  

  I have a couple of problems/issues though....

1: The ring comes in as a cell (kind of like when you make a 2x2 via) that I can't chop, stretch, etc.  Is there a way to make it choppable, or do I have to flatten it and get back to a ton of contacts in the database slowing things down?

2. Some of the contacts come in off grid.... that's just freaky.  Should it be getting the grid resolution from the initial techfile?

3. Probably won't come up often, but when I make a 45, some of the contacts do not follow the minimum contacts spacing rule.

Or, is all of this in the documentation and I just have to start reading again?

Thanks again, I really appreciate your help.

Dan

Hi Dan,

1. Fluid guardrings are implemented as a cell instance, the master is a PCell.  So your alternative here is a ROD multi-part path guardring which could be choppable, or some custom approach for specific situations. In IC615 for Create Via there is the ability to define the cut pattern,and this can be all sorts of shapes, e.g. diagonal, checkerboard, stripes and so on.  There are times when an FGR might be advantageous, and there may be times where an MPP is the better choice - YMMV.

2. Data should not be created off grid - I suggest a Service Request to Cadence Customer Support to investigate if there is a bug.

3. I only looked at one example of a diagonal path; in my case the diagonal contacts were cuts with vertical and horizontal edges (i.e. not following parallel to the diagonal edges) and the horizontal and vertical edges were spaced apart by the min distance (say 0.22, so the corner to corner spacing was 0.311) . What do you have the Contact Spacing Method set to, distribute or minimum? The latter choice should use the minimum spacing rule, but the former will be minimum or larger, as needed to "share" any excess space between the cuts.

You may be able to tell that I don't have a lot of experience playing with FGRs, so some of this might come down to reading the docs, and some of it might be due to a bug.

Regards,

Lawrence.

If you do Edit-> Fluid Pcel, or Windows->Toolbars->Guardring you end up with utilities that allow you to chop, reshape, tunnel, heal and various other operations on the placed guard ring - so they can be manipulated like level-0 objects.

Andrew.

 Thank you both!   That seems to be working for me now.

Now to find all the documentation and see what other fun stuff I can find.

Thanks again,

Dan