Outline for Lab 3:- Finish a partially complete inverter layout (nwell & metal drawn).o Why would you do this in the real world?o Your job is to fill in the rest, stay within the template.o Don’t forget pins, and use appropriate direction types (didn’t do this last time). All pins should be on METAL1 layer. The labels in the original layout are not pins – they are just notes for you, and should be deleted.o Don’t forget NWELL and Substrate contacts.o Net names in the “Bulk node connection” for the NMOS and PMOS instances must match the actual net names for the bulk connections.- Create a schematic view for the inverter – directly analogous to the layout view.o Schematic editing is a lot like layout editing, but with symbols instead of shapes.- Hierarchy works the same way, same basic keystrokes (instantiate, move, copy, Escape), but a few are different (Save). o NMOS/PMOS instances have mostly the same parameters- Watch out for “Bulk node connection”o Create pins in the schematic that match pin names in your layout. Also make sure the input/output directions match the layout.o “Check and Save” makes sure you don’t have any drawing errors.- Use Layout XL to check correspondence between schematic and layout views- (Optional) Crosscheck layout and schematic with LVS.Tutorial moved to:http://inst.eecs.berkeley.edu/~ee141/lab3/tutorial.pdf, orhttp://inst.eecs.berkeley.edu/~ee141/lab3/tutorial.doc Corrections:- Don’t create any new NWELL shapes – stay inside the bounds of the existing NWELL rectangle.Help creating your new library and Inv1 layout cell:- Copy ~ee141/cds.lib into your new directory for this lab before starting Cadence.- Start Cadence from your new directory (with the command “icfb &”) Should see NCSU_Techlib, NCSU_Analog_Parts, and basic in the library manager- Create a new library called “Inverter” don’t need to specify a path – it creates a subdirectory under the directory you launched Cadence from.- Close your new (blank) Inv1 layout before copying files overGeneral Cadence Tips- Save often! (F2 key)- Run DRC frequently – maybe even after every shape or two. Uncheck the “Echo Commands” option for faster run times. - Use WindowClose command to close a window – don’t just hit the “X” button.Help with Pins:- Pins consist of a label (for your benefit only) and a shape (which indicates connectivity to Cadence). Don’t forget to put the shape on the correct layer.- When creating pins, use type “shape”/”rectangle”, and make sure the “Display PinName” is turned on. “Display Pin Name Options…” to chose different text sizes.- Set “I/O” type to input/output for VIN & VOUT, and inputOutput for supplies.Things to check if you have viewing/selection problems in cadence- OptionsDisplay…X/Y Snap Spacing should be 0.06 each- OptionsLayout Editor… Gravity On should be unchecked- Check the LSW – make sure all layers are visible (AV) and selectable (AS). Also,make sure you chose the right layer before drawing any shapes/pins.- Use Crtl+f and Shift+f to hide/show subcell details- “f” to fit the entire display to the window – helps if you get “lost”- click & drag with right mouse button for fast zooming.Useful editing/selection/measurement commands:- Press “esc” a few times if it is stuck in the middle of a command and you are confused, finished with the command, or just want to back out.- Ctrl+d will deselect everything. This is often useful right before starting a command to make sure you haven’t accidentally selected something you don’t want.- “k” allows to draw rulers, useful for measuring and alignment. “K” will erase
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