Page 267 - A Practical Guide from Design Planning to Manufacturing

Chapter
8

Layout

Overview
This chapter shows how circuit design is converted into layout. The
chapter describes the different layers of material that must be drawn
to define transistors and wires, the typical design rules that must be fol-
lowed, and some common pitfalls in creating layout.

Objectives
Upon completion of this chapter the reader will be able to:

1. Visualize the three-dimensional structure to be manufactured from
a piece of layout.
2. Describe the different layout layers used to draw a transistor.
3. Draw the layout for a CMOS gate.
4. Understand how design rules influence the size of layout.
5. Review layout for some of the most common mistakes.
6. Determine drawn, schematic, and layout transistor counts.
7. Understand three different methods of shielding wires.
8. Describe electromigration.

Introduction

Layout is the task of drawing the physical dimensions and positions of
all the layers of material that will ultimately need to be manufactured
to produce an integrated circuit. Layout converts a circuit schematic to

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