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  1. #1
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    Layout Abutment Sitting in the TSMC PDK

    Hello,

    I'm working with TSMC PDK and I faced a problem in abutment setting in the Layout L Editing.
    However, when I use the Layout XL, The elimination of the contacts of the Drain/Source of two transistors which are connected to each other and i haven't any contact from them will do automatically but I cannot do that in the Layout L environment manually. I remove the contact of source or drain but the diffusion region of contact will remain. I did that several times in the other PDKs but this time I have this problem.
    I would be appreciated if someone has any experience towards this in the TSMC PDK share it with me.

    Thank you in advance!

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  2. #2
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    Re: Layout Abutment Sitting in the TSMC PDK

    The best thing to do would be to turn off auto abutment. I never have that enabled because it’s very common to run into issues with it in layout xl. In layout xl go to: options—>layout xl...—>generation. From there deselect abut transistors to turn this feature off. This issue tends to occur once you share diffusions of multiple devices.



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  3. #3
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    Re: Layout Abutment Sitting in the TSMC PDK

    Quote Originally Posted by ljp2706 View Post
    The best thing to do would be to turn off auto abutment. I never have that enabled because it’s very common to run into issues with it in layout xl. In layout xl go to: options—>layout xl...—>generation. From there deselect abut transistors to turn this feature off. This issue tends to occur once you share diffusions of multiple devices.
    I couldn't describe my question correctly. I cannot do abutment for transistors manually in the Layout L. I haven't any problem by the Layout XL.
    In the Layout L when I remove a contact of drain/source manually just its metal will be removed and its diffusion will remain. Whether this can be the PDK installation problem or something else.



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  4. #4
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    Re: Layout Abutment Sitting in the TSMC PDK

    I think you can leave both contacts on. Just overlap the shape exactly and it’ll only recognize it as a single contact/diffusion. Should pass DRC that way. If not, once you overlap it, remove the contact of one of the devices. If you overlap shapes in layout, it just looks at the total area of the shapes, not the various layers of that shape. Once everything is done, its essentially flattening all your shapes. Also, as long as you meet DRC rules, diffusion shape outside active+gate doesn’t matter. You can create a dogbone diffusion if you need to add more contacts so you don’t have lonely via violations.



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