I am looking for an open-source circuit layout routing tool (with scripting option) for custom layout design. For example: I design a NAND schematic and convert it into layout and place components (NMOS and PMOS) by myself and then auto-route it. If found Qrouter from OCD but it requires standard cells for routing. I don't want to use standard cells I just want to place individual components and then auto-route the design. I have checked KiCAD and gEDA but they are used for PCB designing and I couldn't find to control or program then with scripting. Could anyone recommend some other options for me? Can't I use VLSI routing tools without standard cells ?.



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No, you can't (with standard tools) do autorouting of transistor-level designs without standard cells. There are many issues that must be addressed when creating VLSI designs that are beyond the abilities of automated routers. The standard cell library is hand-crafted in such a way that these issues are invisible to the autorouter. For example, an efficient VLSI design must carefully plan the location and width of the power lines so that the P-well and N-well contacts (taps) can be made without blocking the routing of polysilicon gates. Unlike PCB design, the minimum pitch of every routing layer may be different and the sheet resistance of some layers may be much higher than others.

  • \$\begingroup\$ In that case, I will use KiCAD and the documentation says that it supports python scripting (at least the layout view). Thank you! \$\endgroup\$ – frasheed Jul 16 '18 at 16:15
  • \$\begingroup\$ As you like, but I would be very surprised to learn that KICAD can do VLSI layouts. You might take a look at Electric: staticfreesoft.com/electric.html \$\endgroup\$ – Elliot Alderson Jul 16 '18 at 16:47
  • \$\begingroup\$ KICAD cannot do VLSI layouts, I will use it because it will serve the purpose (discrete components routing). I know electric as well but the problem is again standard cells routing (because of the grid routing algorithms). \$\endgroup\$ – frasheed Jul 16 '18 at 19:27

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