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abutment and controlling S/D dropping

RonSill

I am an end user layout engineer. I am not a developer of PDKs or Pcells, etc. so I am at the mercy of what is given me to use for the most part. I do develop SKILL code for automation of the layout task. One of the problems we encounter is when we abut pcell mos devices and the source/drain of one of the abuted devices drops off. That is all fine except sometimes when you pull the devices back apart the source/drain does not come back. This is a problem and probably has something to do with the way the pcell was created. If I happen to instantiate any new pcells of the same type the source/drain will also be missing on the new device as well. 

As an end user in most libraries I found that if I view the properties of the pcell most our libraries have a 'disable callback' button I can click on, apply the form, then click off and re-apply the form and the source/drain comes back and all is well.

My issue is that I am developing some Skill code that copies a selected pcell into another view, flattens it and extracts data but I need the source/drain to always be there so I can extract data off the shapes. Is there a way I can trigger this new view copy to get the source/drains back? Is there a Cadence functional way to maybe disable and re-enable calbacks to it to maybe do with Skill code what I do manually? I've been looking and can't seem to find an answer.

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  • theopaone

     When you dump the pcell code, you are looking at the superMaster of the pcell. This does not include the abutment code but the two parameters you mentioned, leftDiffState and rightDiffState sound like that they control the diffusion during abutment.

    The abutment function should have saved the original state of the parameters on the abutment group but it doesn't look like it. You could find the abutment function assigned to the pins and fix it or you could restore the default value to the parameter once you have un-abutted the instances.

    Ted

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  • theopaone

     When you dump the pcell code, you are looking at the superMaster of the pcell. This does not include the abutment code but the two parameters you mentioned, leftDiffState and rightDiffState sound like that they control the diffusion during abutment.

    The abutment function should have saved the original state of the parameters on the abutment group but it doesn't look like it. You could find the abutment function assigned to the pins and fix it or you could restore the default value to the parameter once you have un-abutted the instances.

    Ted

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