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How to turn off blinking, diamond-shaped markers on the fet geometry in layout

SC6789

Our group has recently switched to Cadence 6.1.8-64b.500.19 from 615, and we updated our design kit accordingly. Opening my previous designs, I see numerous diamond-shaped markers blinking at various places of each FET device in the layout. They are present in both Layout L and XL.

I can't get rid of them using Verify->Markers-> Delete All (No markers match this criteria). I can't find or explain them using ...Markers->Find or Explain. Also I can't get rid of them using Calibre->Clear Highlights (we use Calibre for verification). The layout and schematic pass DRC and LVS. The markers located on the ends of the poly fingers remind me of Weak Connect terminal warning markers. But if they were those, I should be able to Delete them or Explain them; but can't do that in this case. Also here they are present on the dummy polys as well as diffusion contacts, which I've never seen before.

They are so dense that when zoomed out on the full layout, they obscure the layout making it impossible to work. What other switches can I try to see if I can get rid of these, or at least understand what causes them. These markers are only present on fet devices, not general metal routing, resistors etc.

Screenshot is attached. Thank you in advance!

  • Andrew Beckett

    These look like stretch handles on the transistor PCells. I don't see too many PDKs using these, but if you're using a PDK that supports them, it appears that somebody has turned the display of stretch handles on (it's off by default). This is controlled by this setting on Options->Display in the layout editor:

    Which layer is used to display the stretch handles is controlled by a cdsenv setting:

    envGetVal("graphic" "stretchHandlesLayer")

    (or you can search in the CIW Options->Cdsenv Editor for "stretchHandle"). You can change the layer using:

    envSetVal("graphic" "stretchHandlesLayer" 'string "y3 drawing")

    or the default for whether it's enabled/disabled or not using:

    envSetVal("layout" "displayStretchHandles" 'boolean nil)

    Note that it's possible that the default has been set on the cellView (less likely), library or (quite likely) technology library in the properties for the library itself. Can cover that if just changing the env var doesn't fix it.

    Regards,

    Andrew

  • SC6789
    in reply to Andrew Beckett

    Thank you, Andrew! Disabling the stretch handles in Display Options made them invisible and mediated my issue. And envSetVal("layout" "displayStretchHandles" 'boolean nil) SKILL cmd works equivalently well.

    In my limited understanding, it makes little sense to attach stretch handles to FETs, since their size is defined parametrically, not by stretching them. But that's fab's decision in making the design kit and is a separate discussion.

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