Manufacturing

Manufacturing Concerns

Microprocessor Construction / 3D Chips / Volumes Dictate Markets / Packaging / Building Systems

Microprocessor Construction

The Microprocessor or just processor is a small thin chip of silicon crystal, typically less than half a square inch. The square of rectangular packaging that fits into a socket on the motherboard protects the processor from contaminants (such as air) and allows it, through the pins, to engage the motherboard's circuits and hence the system as a whole. Silicon is widely available and inexpensive and it's therefore the most popular material for construction.

Silicon also works well because it can form large crystals of uniformly high quality. Each crystal is about 8in. across, which is important because manufacturers want to cut each one into as many chips as possible.Manufacturing a chip is a complex process involving hundreds of steps, demanding incredible precision and constant testing. Wastage is often an economic consideration, and sometimes new production / marketing strategy is employed to offset waste. The transistors are laid out along microscopic lines made of superfine traces of aluminium to form the circuits, which can store and manipulate data. >>>>

Chip fabrication plants are the most complex, precise and clean facilities on the planet and cost hundreds of millions to build and run. However the raw materials used are ubiquitous and cheap. Designing an eight million transistor chip takes large teams of engineers many months or years. The incremental cost of each chip once the design has been finished and the chip fabrication is working is very small.

A processor is also an integrated circuit (IC), a silicon chip that contains millions of transistors, a transistor being a 'switch' representing either one of two 'states' and operated by small voltages. Patterns of these switches are used to form circuit logic. Instructions from a program 'fuel' the circuitry to perform the required function.

Developments in the art of semiconductor design and manufacturing them in smaller sizes make it possible to continually produce higher performance microprocessors. If improved design results in shorter distances for electrons to travel, the device has a faster throughput, the ultimate goal of a microprocessor. A by product of miniaturization for any semiconductor device is speed. The shorter the distance a pulse travels, the faster it gets there. The smaller the elements in the transistor, the faster it switches. Transistor speeds are measured in billionths and trillionths of a second. A Josephson junction transistor has been able to switch in 50 quadrillionths of a second.

There is also the option of larger, more powerful or more integrated circuitry being designed into the same space, the best examples being math co-processors (with the first 486 chips these were a performance 'add on' for mathematically intensive work, but since later 486's included as standard) and cache. Caches (as the name suggests) provide an intermediate stage to and from the main memory store, giving performance benefits, cache silicon is more expensive to produce but quicker in operation and is therefore used strategically. Integrated circuits (ICs) reduce manufacturing costs if the circuitry of individual components can be more densely packed on a single chip,

3D chips.

ICs also reduce the interface needed between components and the corresponding delay of spanning a secondary medium other than silicon etching. Sub-micron process technology (less than one millionth of a meter) allows the design of chips with more densely packed transistors while the space they occupy decreases. The induction from 1.0 to 0.35 microns gave a six fold increase in transistor density over two dimensions. Transistors are actually considered 3D devices in silicon! The Pentium has four conducting layers, allowing for distance optimization in three dimensions. There are yet lower limits and 0.35 microns is approaching the wavelength of light used in the photo lithographic manufacturing process

Thus small changes in the silicon processing technology can have a dramatic effect on the number of transistors possible on a chip, which is why there are so many incremental processor upgrades. Numbers of transistors have grown from 2300 on the 4004 in 1971 to 5.5 millions on the Pentium Pro. Also smaller transistors use less power and so dissipate less heat (heat can affect reliability and performance.) However, this must be balanced against faster operation of the transistor, leading to more heat. Smaller transistors cost less to build because you can fit more on a silicon wafer. For a mechanical description of chips and many other definitions follow http://www.techweb.com/

Volumes dictate markets.

Intel are continually increasing the performance of their processor range and other products, there are regular incremental improvements in the clock speed of processors. Production capacity must be therefore shared across a range of models leaving Intel with a variety of product specifications. Consider the Pentium PRO which contains nearly twice as many transistors as a 'normal' Pentium and so is much more expensive to manufacture. Intel's strategy therefore was to market the PRO not as a direct successor to the Pentium but as a 'high-end' desktop or 'server class' ( a 'server' on a network supports several users ) alternative. Heavily computational / graphics intensive markets

are always hungry for more power, and are willing to pay. Traditionally, they drive the CPU market forward. Imagine that a new Intel processor (called chip 'X') is 'positioned' at the 'high-end' but smaller market, this is appropriate to a smaller production run and can demand a higher price. Eventually, a new design will emerge for production with greater performance, ( remember the competition will be fighting back ). Intel will have gained more confidence with their chip 'X' ( and it will have gained some familiarity in the marketplace ) and so will increase volumes and drop prices. Use of the chip migrates to mainstream business and consumer PC's.

Intel adopts a careful pricing and production strategy to combat its rivals ( who are mostly in the form of AMD and Cyrix.) when these clone manufacturers begin to compete effectively with their existing products. Intel give the 'low end' and 'mid range' market access to its latest chips by making

stocks available and prices attractive. The cycle continues with a new chip at the high end. Eventually a 'low end' chip will go completely from the range. The idea is that the competition will find itself permanently behind in the race for market supremacy.

Packaging

Packaging not only protects the chip but also dissipates heat and connects it to the motherboard. The 80286 processor introduced the pin-grid array (PGA) packaging. This is usually square and the pins are aligned in three or four squares nested inside each other leaving a blank central area. The pins fit into the corresponding holes of the socket module in the motherboard and the package is locked in place by a levered arm. For more advanced CPUs, more pins were required and Pentium CPUs use a staggered PGA (SPGA) design, which allows the pins to fit closer together.The Pentium Pro, because it has separate chips for the CPU and level 2 cache, uses a design called the Multi-Chip Module.

An MCM is a package that contains more than one chip. Another recent package, the leadless chip carrier (LCC) uses tiny pads of gold instead of pins to make contact with the motherboard. Other packages include the tape-carrier package (TCP), which is as thin as photographic film and is soldered onto the motherboard (for notebooks), and the single edge contact (SEC) cartridge, used by Intel for the Pentium II. This is a PGA package mounted on a small 'daughtercard' that's then attached to the motherboard through a Single-Edge Connector. The SEC takes up less space on the motherboard and has better elctrical characteristics.

Building Systems

Intel policy is to sell to 'recognised distributors' and OEM's (Original Equipment Manufacturers such as Compaq, Packard Bell, Dell or Gateway) who buy in multiples of 1000, on a 1000 unit price from Intel. They do not sell direct to resellers. Chip sets, motherboards as well as the processors may be bought in complete sets. System builders or 'Integrators' will merge components such as processors, motherboards, chip sets, sound and graphics subsystems, interfaces, hard, floppy and CD ROM drives, all essential to a modern 'basic' system from a variety of sources.

These systems can be 'Built To Order' typically from a company focused on assembling and supplying PC systems and using quality components at lower prices. Flat management structures provide a a better service than from slow moving, big multinationals and because PC technology moves at rapid pace, a PC system from a retail outlet may depreciate whilst sitting in the store. Systems built on the day an order is placed can be delivered by mail order with no middleman involved to give the best price. As newer products emerge Distributors and OEM's drop their prices to remove older stock




		Site Map