ABSTRACT
VLSI (Very Large Scale Integration) is a technology that has enabled the manufacture of large circuits in silicon. It is not uncommon to have circuits containing millions of transistors, and this quantity continues to increase very rapidly. Designing a VLSI circuit is itself a very complex task and has spawned the area of VLSI design automation. The purpose of VLSI design automation is to develop software that is used to design VLSI circuits. The VLSI design process is sufficiently complex that it consists of the four steps shown in Figure 52.1. Architectural design is carried out by expert human engineers with some assistance from tools such as simulators. Logic design is concerned with the boolean logic required to implement a circuit. Physical design is concerned with the implementation of logic on a three dimensional physical structure: the VLSI chip. VLSI physical design consists of steps such as floorplanning, partitioning, placement, routing, circuit extraction, etc. Details about VLSI physical design automation may be found in [1-3]. Chapter 53 describes the rich area of data structures for floorplanning. In this chapter, our concern will be with the representation of a circuit in its “physical” form. In order to proceed with this endeavor, it is necessary to first understand the basics of VLSI technology.
