Page 14 - Semiconductor Manufacturing Handbook

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Source: SEMICONDUCTOR MANUFACTURING HANDBOOK

CHAPTER 2

IC DESIGN

Ilsun Park
Advanced Micro Devices
Austin, Texas

2.1 INTRODUCTION

In 1947, Drs. John Bardeen, Walter Brattain, and William Shockley discovered the transistor effect
while working as researchers for Bell Labs. Prior to the invention of the transistor, bulky, unreliable
vacuum tubes were used in electronic circuits. Eleven years later, Jack S. Kilby, an engineer at Texas
Instruments, and Robert Noyce, cofounder of Fairchild Semiconductor, took the idea of miniaturiz-
ing circuits one step further and created the integrated circuit. The first commercially available inte-
grated circuit was available in 1961, and comprised one transistor, one capacitor, and three resistors
and was the size of a postage stamp. Forty years later, the AMD Opteron processor die had over
100 million transistors in an area smaller than a fingernail.

2.2 TYPES OF ICs

The first integrated circuit (IC) was used in missile guidance systems and pocket calculators. Today,
there are many different applications of integrated circuits.
Dynamic random access memory (DRAM) is used in most personal computers due to low cost
and small size. Each data bit is stored in a separate capacitor that leaks charge over time and thus
needs to be refreshed periodically to keep its value.
Unlike DRAM, a static random access memory (SRAM) cell will retain its value as long as
power is applied. This is accomplished using transistors and is thus more expensive and harder to
produce than DRAM. SRAM is generally faster than DRAM.
An electrically erasable programmable read-only memory (EEPROM) is a nonvolatile memory
that can be erased and reprogrammed electrically. The EEPROM can store data even when there is
no power applied to it. An EEPROM can be rewritten a limited number of times, but can be read any
number of times.
The microprocessor is the largest and the most complex example of an IC. Often referred to as a
central processing unit (CPU), the microprocessor is designed to perform many different functions.
A microprocessor comprises many different units, including an arithmetic logic unit, a floating point
calculation unit, and cache memory.
An application specific integrated circuit (ASIC) is an IC that is designed for a specific task or
purpose, unlike the microprocessor. Because custom ASICs can be very costly to design and pro-
duce, many designers will often substitute a field programmable gate array (FPGA) for smaller

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