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Manufacturing grid/ Routing grid

Cristina Ibane

Hi!

Is there any way to customize the values for these 2 grids? I understand they are currently read from the tech file and I do not want to touch that.

I have found some answers related to creating a new constraints group and defining the new grid, but I do not find any process rule that would allow me to do that.

Just to be clear: in my environment, package metal needs to be routed with a different grid from the rest. If I use paths to do this, my 45degrees angles won't respect the bigger grid. The only solution I found is SKILL snapping them to grid, but only after converting them into polygons, which is not exactly what I would like to do each and every time on each and every package.

Any input is highly appreciated! Thanks!

  • Andrew Beckett

    What you could do (and this is probably the right thing) is to use ITDB (Incremental Technology Database). If you create your design library and reference the technology library rather than attaching it, you can add your own constraint groups within the library. Or you can create a new library solely for this purpose, reference the technology library, and attach your design library to your newly created "superset" technology library.

    Having created a library with a reference, you could dump the tech file and add in the constraint group definition, or you could use the Process Rule Editor in the constraint manager to do this (although that's not entirely obvious).

    You probably want to create a constraint group which looks similar to LEFDefaultRouteSpec in <ICinstDir>/tools/dfII/samples/techfile/sample2007.tf 

    Not sure you necessarily want to override the mfgGridResolution though - I assume you could do this too in the Increment Technology Database (I've not tried, so I could be wrong).

    Regards,

    Andrew.

  • Cristina Ibane
    Thanks for this, it does seem to work and partially solves my problem!

    I am now facing the following thing (it is a little bit different topic, but...): my path centre line is totally on grid, but if I use 45deg paths, the extreme points of the joints are off grid.

    Is there a way to fix this by same constraints definition?

    Thanks!
  • Andrew Beckett

    Paths inherently have their outside vertices off grid if you have 45-degree segments, because they have constant width. You should use pathSegs (via the Create Wire command) as these are designed to keep the edge vertices (and centre vertices) on the manufacturing grid.

    Andrew.

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