Occasionally someone will come into my store and mention something that rattles my memory banks and sends me back in time. I was pleased when a customer innocently mentioned the “little plastic chips” soldered to the motherboard and asked how plastic can transfer data. I rewound instantly to a dozen years ago when I used to work in the semiconductor industry.
After working in the semiconductor industry I started a supply house focusing on a specific portion of the industry and ventured on my own. It was a fairly successful venture until the fateful 9-11 tragedy which limited importation from China and the East. I’ve decided to truncate that decade of experience into 600 words so I’m only going to touch on highlights and try not to bore you.
Modern semiconductor technology was first created in 1941 when Russell Ohl discovered a voltage change when a sliver of silicon was exposed to light. Ohl was a researcher at Bell Labs during that time and is credited with patenting the first solar cell. Ohl also discovered that electricity passed at different levels depending on the number of impurities within the substrate.
Certainly the most common material used in semiconductor manufacturing is silicon; however, other materials have been used including germanium and silicon carbide. Manufacturers use different materials depending on desired outcomes. Obtaining results for a specific purpose can be achieved by amalgamating different materials and creating an aggregate compound.
Most of the semiconductors on the market today start with ordinary sand. Without getting too embroiled in technical mumbo jumbo, I’m going to boil down the process. Basically the sand is melted in a crucible and is formed into a cylinder of the desired diameter. Similar to candle making, the cylinder is dipped and re-dipped during the process.
In my hay day, the most common diameter wafer was 120mm. Today it’s not uncommon to see a 300mm wafer used in industry. Wafers are cut from large cylinders created in the forming process and are then sent through a polishing progression to remove surface impurities. Typical wafers are ultra thin and can range from 0.2mm to 0.75mm thick.
Once the wafer is prepared it is then passed to a second and more critical process where it is super heated and dosed with a massive amount of oxygen. During this step the wafer is coated in silicon dioxide; an outcome of heat combining with silicon and oxygen.
Who would think a basic photographic process would be used to make an integrated circuit? A very old process called photolithography is used to burn the desired image into the surface of the wafer creating the desired circuit. Once the image is burned into the surface, the wafer is chemically washed and inspected.
Other materials are added to the wafer depending on the circuit’s purpose. Wafers can be stacked with different insulators called dielectric layers to create large integrated circuits. Today’s Intel and AMD processors may have three layers of silicon to create the backbone of a powerful computer. Whereas most common semiconductors typically have only one layer.
Before the circuit can be used it has to be cut and packaged. Larger wafers are trimmed to the desired size with a diamond saw and wire leads are attached. This package is molded into a plastic shell and additional leads are attached which can then be used attach to the end product.
I hope I didn’t bore most of my regular readers with too much technical stuff; but I thought it was important to get back to the basics. If one person was slightly confused then I’m sure there’s more. The irony of the whole process is understanding the basic product originates from sand which may make you rethink purchasing your next computer.
(Jeromy Patriquin is the President of Laptop & Computer Repair, Inc. located at 509 Main St. in Gardner. You can call him directly at (978) 919-8059) or visit www.LocalComputerWiz.com.