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automatic parametrised layout

Sabyasachi

 hello all ,

                 I am novice in SKILL language. Can anybody help me to generate layout of different components. My aim is to write  a SKILL code that will take parameters like length width finger number and will generate layout of the transistor with those given parameter.

Thanking in advance

 

Sabyasachi Deyati
M Tech ( 4th Semester) Microelectronics & VLSI Design
Electronics & Electrical Communication Engineering
Indian Institute of Technology , Kharagpur
  • Hi Sabyasachi

    I am not sure if you are just trying to practise coding pcells but for layout purposes, I think it might be easier for you if you simply use the parametrized cells (pcells) that comes with your process design kit (pdk). A pcell can be a mos, cap, bjt, res, etc and its layout can change according to the parameters (e.g. W and L) that user changes in its properties form.

    Best regards
    Quek

  •  Thanks  Quek 

    Could you please elaborate it . I am using IC 5141 version. Could you please tell me how to use those  pcells

  • Hi Sabyasachi

    You simply need to open a new layout, press "i" to bring up create instance form, browse to any pcell in the technology library and place them in the layout. You can now change their parameters using the properties form.

    To have an idea of how pcells work, you can use the cell design tutorial in the IC5141 installation:
    unix>cp -r $CDSHOME/tools/dfII/samples/tutorials/le/cell_design ~
    unix>cd ~/cell_design
    unix>icfb &

    Open layout of cell "inv" from "master" library. Change some of the parameters (W, L, fingers) of the nmos and pmos and observe how the layout changes.

    The tutorial manual is located at: $CDSHOME/doc/celltut/celltut.pdf

    By the way, actually IC5141 release spans at least 7 years so actually "IC5141" alone does not provide much useful info. It would be great if in future, you can also provide the specific sub-version:

    unix>icfb -W

    Best regards
    Quek

  •  Hi Sabyasachi,

    In addition to what Quek has said, there are some sample SKILL PCell code examples in the installation hierarchy, and also a generic Process Design Kit ("gpdk") that you can look at and play with.  Take a look in the following directories:

    <cds_install_dir>/tools/dfII/samples/ROD/rodPCcells

    <cds_install_dir>/tools/dfII/samples/tutorial/abstract/pdk

    where "<cds_install_dir>" can be found using "cds_root icfb", for example. Also the documentation contains example PCell SKILL code, though you may have to dig for it.

    regards,

    Lawrence.

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