Chapter 3. How Chips Are Designed

In this chapter...

• Old-Style Design Process

• New-Style Design Process

• Verifying the Design Works

• Using Outside IP

• Getting to Tape Out and Film

• Current Problems and Future Trends

Chip design has come a long way since the first semiconductor chips were assembled, literally, by hand. Rarely does a profession reinvent itself so often and so fundamentally. New chips today are designed in a completely different manner from those of just 10 years ago; it's almost certain that the job description will change again in another 10 years.

New chips are designed, naturally enough, with the help of computers. These computers (often called engineering workstations) and the chips inside them were themselves designed this way, providing a nice circular closure to the entire process. The computers that chip-design engineers use are not fundamentally different from a normal PC, and even the specialized software would not look too alien to a casual PC user.

That software is breathtakingly expensive, however, and supports a multibillion-dollar industry all by itself. Called electronic design automation (EDA), the business of creating and selling chip-design software supports thousands of computer programmers around the world. Chip-design engineers rely on their computers and their EDA software “tools” the way a carpenter relies on a collection of specialized tools. There are a handful of large EDA vendors, notably Synopsys (Mountain View, California), Mentor Graphics (Portland, Oregon), and Cadence Design Systems (San Jose, California) that are the equivalent of Craftsman, Stanley, and Black & Decker. There are also numerous smaller “boutique” EDA vendors that supply special-purpose software tools to chip designers in niche markets.

Regardless of the tools a chip designer uses, the goal is always the same: to create a working blueprint for a new chip and get it ready for manufacturing. In the chip-design world, that's called “getting to film,” as film is the ultimate goal of a chip designer. The film (which is really not film any more, as we shall see) is used by chip makers in their factories to actually manufacture the chip, a process that's described in the next chapter.