Aluminum Migration & ESD

Semiconductors do wear out! Contrary to the beliefs of many, integrated circuits grow old and die, or become intermittent. How they do that varies; modern "chips" as used in computers, have literally millions of transistors printed on a small "chip" of silicon no bigger than your fingernail. Each microscopically small transistor is connected to the others, on the surface of the chip, with even smaller aluminum or copper wires. These wires are only a few thousand atoms wide. Over the years, the thermal stress of turning the computer on and off can cause tiny cracks in the wires. As the computer warms up the wires can part and cause the computer to stop working. Even a few seconds of off-time can cool the system enough to allow the wires to re-connect, so your computer may work just fine for a few minutes, or hours, then after it warms up, it may fail, letting it cool off can bring it back to life for a few minutes or more.
Some chips are much more prone to premature failure than others. Intel, one of the best chip manufactures, designs their parts to be very robust and tolerate heat and mishandling better than others. (This, of course, costs time and money.) Some of Intel's competition tries to garner market share by building cheaper or faster chips. Cheaper and faster means hotter and shorter-lived parts. All manufactures, from houses to toasters, walk a narrow line between quality and price. Too much quality and the price goes up and nobody buys their products. Too little quality and the product dies of old age too early and they get a bad name, and can't sell their product. Most modern computers, especially the lower priced ones, are constructed from the cheapest parts available. When the big names in the computer industry promote their products by price alone, they just can't put too much quality in them.

By far the most common failure mode of a modern integrated circuit is aluminum migration. The small aluminum wires of a chip are arranged in parallel rows very close to each other. Heat, electricity and time, can cause the aluminum of one wire to slowly flow across the gap between the wires, and eventually short out the chip. Most quality chips are designed to minimize this migration, and usually will run for decades before they short out, but many things can speed this failure process. Cheaper parts, excessive heat, marginal circuit design, or bad handling, can cause the premature death of a chip through aluminum migration.

Integrated Circuit (IC)



Over sized & colored to better show areas of the chip. The Intel Pentium 4 is about the size of your thumbnail and contains over 43-million transistors, and many thousands of exceedingly small wires.

The faster a computer runs, (higher megahertz or gigahertz) causes the chips to create more heat, and heat will speed the migration of the aluminum. Some computer designers, in order to save a little money, may push the chips past their design limits. Running a chip just a small amount faster, or at a slightly higher voltage than its design limits can speed its demise. Many of the cheaper computers are designed in such a way as to maximize the manufacture's profits but minimize the lifespan of the product.
The most insidious and least understood cause of chip failure is ESD "Electro Static Discharge". Chips can be electrocuted by very small amounts of static electricity (much smaller than can be felt) can kill, or make a computer chip intermittent. Us human beings create lots of static electricity. All the dozens of people who have touched the chips inside your computer, from manufacturing the chip, building or repairing your computer, or adding new parts to the inside of your computer, have had the opportunity to touch, or mishandle, the chips inside your computer.

ESD Damage


Before

After
The above is an electron-microscopic picture of one of 43-million transistors in the Intel Pentium 4 computer chip. Each transistor is smaller than a microbe. (And getting smaller each new generation.) One small touch from the finger of a careless person can damage or destroy hundreds of these microscopic transistors in an instant.

One klutzy computer technician mishandling the insides of your computer can easily cause one of the hundreds of integrated circuits in your computer to become prematurely aged through ESD. Simply taking the covers off your computer and touching its internal components can cause a chip that should have lasted for decades to die, or become intermittent, in just a few weeks or months. Did someone take the covers off your computer a year ago? Well… That could be the cause of your problems today! Don't allow anyone that doesn't understand ESD, or work in an ESD safe area, to touch the insides of your computer! (That includes most of the so-called professionals.)