SIC 3674 Semiconductors and Related Devices
SIC 3674
This category covers establishments primarily engaged in manufacturing semiconductors and related solid-state devices. Important products of this industry are semiconductor diodes and stacks, including rectifiers, integrated microcircuits (semiconductor networks), transistors, solar cells, and light sensing and emitting semiconductor (solid-state) devices.
334413
Semiconductor and Related Device Manufacturing
No longer wholly dependent on personal computer sales, in the mid-2000s the U.S. semiconductor industry provided components for a wide range of consumer and industrial electronics. Although the personal computer segment continues to hold 30 percent of the market share, data and telecommunications equipment sales are being driven by the demand for cell phone handsets and digital televisions. In all areas of the market, the semiconductor industry continues to strive to meet consumer demands for products that are stronger, faster, and cheaper.
The industry is notoriously cyclical. After worldwide semiconductor sales grew 40 percent in 1995 to nearly $150 billion, sales dropped in 1996 and were flat through 1998. Sales reached record levels in 2000, totaling $204 billion. However, they fell sharply the following year, dropping to $139 billion as the industry experienced the worst year in its history. In the wake of 2001's dramatic decline, tens of thousands of industry workers lost their jobs. However, the industry rebounded during the next few years. After remaining relatively flat in 2002 and 2003, in 2004 the industry reported year-on-year growth of 28 percent, posting record global revenues of $213 billion.
In 2003 the U.S. semiconductor industry accounted for 48 percent of the global market with $80 billion in U.S. sales. Of total shipment values, 73 percent of U.S.-produced chips were exported. According to the Bureau of Labor Statistics, the U.S. semiconductor industry employs approximately 226,000. The U.S. and global computer microprocessor sector is dominated by Intel, which holds 80 percent of the worldwide market.
Sometimes referred to as "the crude oil of the information age," semiconductors are a pervasive but generally unseen aspect of everyday life. The tiny electronic circuits etched on chips of silicon are critical to the operation of virtually all electronics, from automatic coffee makers and antilock braking systems to cellular phones and supercomputers.
The computer industry is by far the largest market for semiconductors. In the early 2000s, sales to computer manufacturers and related enterprises accounted for about 50 percent of overall U.S. sales of semiconductors. Consumer electronics and the automotive industry were also important users of semiconductors and related products. The fastest growing market for semiconductors was related to communications, which accounted for more than 25 percent of sales in the early 2000s, reflecting the rise of a global networked economy that relied on the electronic transfer of data.
Semiconductor chips are manufactured in "clean rooms," free of contaminating dust. In those facilities, thin, round silicon wafers are processed in batches. Chipmakers buy polished blank wafers from companies that specialize in growing silicon crystals, from which the wafers are cut. Each wafer is about half a millimeter thick. Microelectronics circuits are built up on the wafer layer by layer.
Circuit patterns—the collection of transistors, capacitors, and associated components and their interconnections—are inscribed on large glass plates called photomasks. The photomasks are later reduced and photolithographically projected onto the silicon wafers. Each mask comprises a total integrated circuit design.
Semiconductor companies design and manufacture primarily two types of products: integrated circuits (ICs) and discrete devices. A discrete semiconductor is an individual circuit that performs a single function affecting the flow of electrical current. For example, a transistor, one of the most common types of discrete devices, amplifies electrical signals; rectifiers and diodes generally convert alternating current into direct current; capacitors block the flow of alternating current at controlled levels; and resistors limit current flow and divide or drop current.
Also called chips, integrated circuits are a collection of microminiaturized electronic components, such as transistors and capacitors, placed on a tiny rectangle of silicon. A single integrated circuit can perform the functions of thousands of discrete transistors, diodes, capacitors, and resistors. There are three basic types of integrated circuits currently produced by American semiconductor manufacturers: memory components, which are used to store data or computer programs; logic devices, which perform such operations as mathematical calculations; and components that combine the two. This latter category of integrated circuit is the most sophisticated and includes microprocessors, the computer "brain" that manipulates a wide range of data, and microcontrollers, which perform repetitive tasks.
The two largest selling types of memory integrated circuits are DRAMs and SRAMs. A DRAM (dynamic random access memories; pronounced DEE-ram) stores digital information and provides high-speed storage and retrieval of data. It is called a "dynamic" circuit because the data is stored in a temporary medium that allows it to fade, and so must be constantly refreshed electronically.
SRAMs (static random access memories; pronounced ESS-rams) perform many of the same functions as DRAMs, but at higher speeds. Unlike DRAMs, they do not require constant electronic refreshing, hence the term "static." They also contain more electronic circuitry and are more expensive to produce than DRAMs.
Both of these integrated circuit products are manufactured in large quantities and so are considered to be "process drivers." That is, the manufacturing processes used to produce them are constantly being refined, and those refinements often affect manufacturing processes of other products.
Two other important semiconductor memory products are EPROMs (erasable programmable read-only memories) and EEPROMs (electrically erasable read-only memories). EPROMs are used to store computer programs. Unlike older read-only memories (ROMs) that carried fixed programs, EPROMs are programmed by the customer. EEPROMs are easier and faster to update than EPROMs because they are programmed using electricity. While EPROMs are usually programmed only once, EEPROMs can be reprogrammed without removing them from their applications, so they can be updated virtually anytime.
Most logic semiconductors are now customized products tailored to the specific needs of each customer. In fact, ASICS (application-specific integrated circuits) have become the most commonly manufactured non-microcomponent logic semiconductors.
There are four basic classes of ASICs; each class has a different degree of customization of the chip. Full-custom ASICs are designed from scratch; standard cells are designed by combining modular cells from a cell library; semi-custom chips are customized in only one or two areas; and programmable logic devices are programmed by blowing fuses in a device to alter the logic function. Because of high design costs and the often-limited quantities produced, ASICs tend to be more expensive than integrated circuits built from off-the-shelf components. But because they combine several specialized functions on a single chip, they offer some important advantages: they are smaller, simpler, and fewer of them are needed; they allow for a greater degree of integration, which leads to more efficient use of circuitry; and, since they contain less circuitry, fewer interconnections are needed and overall performance...
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