SAMPLE LAYOUT RULES Appendix C

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SAMPLE LAYOUT RULES (Appendix C)
Simplified (not up to date) layout rules in order
to obtain the essential insights.
1. Standard Bipolar Rules
2. PolySi-Gate CMOS and BiCMOS Rules
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1. Standard Bipolar Rules

• 30-V process, single P iso,
• modern process uses Up/Down iso for smaller
  isolation spacing
• Key electrical parameters below

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1. Standard Bipolar Rules, contd.

• baseline process 8 coding layers (in layout
  editors) NBL, Tank, DeepN, Base, Emit, Cont,
  Metal1, POR
• POR Protective Overcoat Removal --- also
  defines Protective Overcoat
• TANK also codes openings in the Iso Diffusion
• BOI (Base Over Isolation) automatically
  generated from TANK layer

Coding Grid 2 um assumed.
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1. Standard Bipolar Rules, contd.

• HSR High Sheet Resistor

• Schottky Contact

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2. PolySi-Gate CMOS and BiCMOS Rules

• 10 V, N-well, poly-gate CMOS as an example
• LDD NMOS, min. channel L 3 um
• SDD PMOS, min. channel L 4 um
• Both NMOS and PMOS have N-type gate Poly
• Single Boron Vt-adjust implant
• Thick-field threshold is safely above op. volt.
• CMOS latchup minimized by P sub and NBL

Typical parameter values

• cant fab Schottky DiodeTi-silicide is used for
  all metalsto minimize contact R

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2. PolySi-Gate CMOS and BiCMOS Rules, contd.

• baseline process 11 masksNWELL, MOAT, NSD,
  PSD, CHST, POLY1, CONT, METAL1VIA, METAL2, POR
• 9 Coding Layers for 11 masksNWELL, NMOAT,
  PMOAT, POLY1, CONT, METAL1, VIA,METAL2, POR
• NMOAT gt MOAT NSD
• PMOAT gt MOAT PSD
• NWELL MOAT gt CHST

• coding grid 0.5 um

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2. PolySi-Gate CMOS and BiCMOS Rules, contd.

• POLY2 Extension 2nd Poly layer deposited as
  near-intrinsic poly Si,
• Poly R Poly2 doped with PSD
• Poly Cap POLY1 \ thin oxide-nitride-oxide \
  POLY2

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2. PolySi-Gate CMOS and BiCMOS Rules, contd.

• Analog BiCMOS Extension 3 more Masks NBL,
  DEEPN, BASE
• Coding layer BASE gt MOAT BASE masks
• NBL forces a 2nd epi
• makes vert. NPN, lat. PNP, and sub. PNP

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3. Layout Rule Syntax
LAYER1 width N um
LAYER1 spacing to LAYER1 N um
LAYER1 overlap LAYER2 N um
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3. Layout Rule Syntax, contd
LAYER1 overhang LAYER2 N um
LAYER1 extends into LAYER2 N um