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STICK DIAGRAM EMT251 Schematic vs Layout VDD VDD M2 In Out M1 In Out Inverter circuit GND Schematic vs Layout VDD 2-input NAND gate VDD B A B Out A 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. 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 VDD VDD Inverter NAND2 Out Out In GND GND A B Stick Diagram Layers Metal (BLUE) Polysilicion (RED ) N-Diffusion (Green) P-Diffusion (Brown) Contact / Via How to design? Logic Graph / Euler Path X A j C C B X = C • (A + B) C A PUN i i X B VDD j B A B C GND A PDN Stick Diagram of C • (A + B) A C B A B C VDD VDD X GND X GND Consistent Euler Path X C i X B VDD j GND A A B C Example A C B D X D X = (A+B)•(C+D) C D A B C VDD X B A B C D PUN A GND PDN LAYOUT DESIGN RULES EMT251 3D View 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) CMOS Process Layers Layer Color 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 Representation Layers in 0.25 mm CMOS process Intra-Layer Design Rules Same Potential 0 or 6 Well Different Potential 2 9 Polysilicon 2 10 3 Active Contact or Via Hole 3 2 Select 3 Metal1 2 3 2 4 Metal2 3 Transistor Transistor Layout 1 3 2 5 Vias and Contacts 2 4 Via 1 1 5 Metal to 1 Active Contact Metal to Poly Contact 3 2 2 2 Select Layer 2 3 Select 2 1 3 3 2 Substrate 5 Well CMOS Inverter Layout GND In VDD Out (a) Layout