Homework_2: Custom Cell Layout

Simple Rules            lambda
----------------------- ------
1. min. width of active = 10
2. min. width of poly   =  2
3. min. poly extension  =  2
4. min. wire separation =  4
5. min. width of metal  =  4
6. contacts are 4x4

Note: active surrounded by n-select --> ndiff
      active surrounded by p-select --> pdiff

Hints for Part B:
Copy an existing (read-only) standard cell (schematic or layout) into your own library.
Use "Add Instance" and access "OSU_AMI06 --> NANDX1 --> schematic".
Use "Create Instance" and access "OSU_AMI06 --> NANDX1 --> layout".
Select the symbol and then select "Edit --> hierarchy flatten".
Edit the schematic and layout as needed.

Remove any existing pins and create new ones; otherwise, LVS may trigger a mismatch.
When you click on "create ---> pins" a box will pop-up for you to supply "pin-name".
At the bottom, select "Access direction" and disable everything except "Left and Right"
for VDD and GND and "Top and Bottom" for inputs and outputs.

Wiring can be facilitated using "Create Path". Metal-2 rules dictate the horizontal spacing of 1.6u or 8-lambda
while Metal-3 rules dictate the vertical spacing of 2.0u or 10-lambda.
Using a grid permits the cell boundaries to overlap horizontally by 4.8u (16-lambda).
Note: The grid layer is "hilite d3" (LSW-->Edit-->Set Valid Layers).
It is best to place pins (4x4 contacts) at a grid intersection.




Case 2:


The vertical overlap of the cell boundaries is 4.8u (vdd) or 2.4u (gnd):



Note how the individual cell grids overlap horizontally by (4-lambda) and vertically by (5-lambda):