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STICK DIAGRAM. EMT251. V. DD. Schematic vs Layout. Out. In. Inverter circuit. GND. V. DD. Schematic vs Layout. 2-input NAND gate. A. B. Out. GND. Stick Diagram. A stick diagram is a graphical view of a layout.
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STICK DIAGRAM EMT251
V DD Schematic vs Layout Out In Inverter circuit GND
V DD Schematic vs Layout 2-input NAND gate A B Out GND
Stick Diagram • A stick diagram is a graphical view of a layout. • Does show all components/vias (except possibly tub ties), relative placement. • Does not show exact placement, transistor sizes, wire lengths, wire widths, tub boundaries.
V V DD DD Stick Diagram • Represents relative positions of transistors • Stick diagrams help plan layout quickly • Need not be to scale • Draw with color pencils or dry-erase markers Inverter NAND2 Out Out In A B GND GND
Stick Diagram Layers Metal (BLUE) Polysilicion (RED ) N-Diffusion (Green) P -Diffusion (Brown) Contact / Via
X PUN C i VDD X B A j PDN GND How to design? Logic Graph / Euler Path A j C B X = C • (A + B) C i A B A B C
Stick Diagram of C • (A + B) A C B A B C VDD VDD X X GND GND
Consistent Euler Path X C i VDD X B A j A B C GND
Example X PUN A C D C B D VDD X X = (A+B)•(C+D) C D B A A B PDN A GND B C D
LAYOUT DESIGN RULES EMT251
Design Rules • Interface between designer and process engineer • Guidelines for constructing process masks • Unit dimension: Minimum line width • scalable design rules: lambda parameter • absolute dimensions (micron rules)
Layer Color Representation Well (p,n) Yellow Active Area (n+,p+) Green Select (p+,n+) Green Polysilicon Red Metal1 Blue Metal2 Magenta Contact To Poly Black Contact To Diffusion Black Via Black CMOS Process Layers
Intra-Layer Design Rules 4 Metal2 3
CMOS Inverter Layout In GND V DD Out (a) Layout