3 Replies Latest reply on Nov 4, 2014 7:45 AM by samantha_lizak

    Parasitics capacitance of metal interconnections

    lpalocko

      Hi everyone,

       

      I design some cells (SRAM cells and etc.) based on Generic Design Kit, but I was a little confused, that cells has poor operating frequency. I investigated this problem and when I find files which defines parasitic value, I was very surprised. Parasitic capacitance are extremely high.

       

      For example:

       

      Technology GDK

      - Feature size 130 nm

      Capacitance intrinsic plate Poly  Mask  0.2 * area()

      Capacitance intrinsic plate M1  Mask  0.1 * area()

      Capacitance intrinsic plate M2  Mask  0.06 * area()

       

      File defines unit capacitance as pF.

       

      In comparison with:

       

      Technology SCN018 (TSMC 0.18u) ftp://ftp.mosis.com/pub/mosis/vendors/tsmc-018/t92y_mm_non_epi_thk_mtl-params.txt

       

      - Feature size 180 nm

       

      Capacitance Poly (Area) to substrate - 101 aF/um2

      Capacitance M1 (Area) to substrate -  34 aF/um2

      Capacitance M2 (Area) to substrate -  14 aF/um2

       

      Resistances are the same in both technology.

       

      Is not problem in unit capacitance? File defines unit capacitance as pF, it shouldn't be fF?

       

      Thanks a lot!