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In this tutorial, a simple CMOS inverter layout will be drawn step by step. We will start with a simple design idea and will complete the mask layout using different techniques.

Steps of Layout Design

• Starting up

  • Design Idea
  • Create Layout Cellview
  • Virtuoso and LSW

• NMOS

  • Drawing the N-Diffusion (Active)
  • The Gate Poly
  • Making Active Contacts
  • Covering Contacts with Metal-1
  • The N-Select Layer

• PMOS

  • Drawing the P-Diffusion (Active)
  • Transistor Features
  • The P-Select Layer
  • Drawing the N-Well

• Connecting both transistors

  • Placing the PMOS and NMOS
  • Connecting the Output
  • Connecting the Input
  • Making a Metal-1 connection for the Input
  • Power Rails
  • P Substrate contact
  • N Substrate contact
  • Enclosing the Substrate Contact

• DRC and Finalizing

  • Design Rule Checking
  • Final Layout

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KGF 11/9/1998