Semiconductor Technicians

There are many steps that occur in processing semiconductors into integrated circuits. The technicians involved in these processes are called semiconductor development technicians and semiconductor process technicians. They may be involved in several or many of the steps of semiconductor manufacturing, depending on where they work. Often, semiconductor technicians function as a link between the engineering staff and the production staff in the large-scale manufacturing of semiconductor products.

The making of semiconductors begins with silicon. The silicon must be extremely pure in order to be of use. The silicon used for semiconductors is heated in a furnace and formed into cylinder rods between one and six inches in diameter and three or more feet in length. These rods are smoothed and polished until they are perfectly round. They are then sliced into wafers that are between one-quarter and one-half millimeter in thickness. Then the wafers are processed, by etching, polishing, heat-treating, and lapping, to produce the desired dimensions and surface finish. After the wafers are tested, measured, and inspected for any defects, they are coated with a photosensitive substance called a photoresist.

The engineering staff and the technicians assigned to assist them prepare designs for the layout of the microchip. This work is generally done using a computer-aided design (CAD) system. The large, completed design is then miniaturized as a photomask when it is applied to the wafer. The photomask is placed over the wafer and the photoresist is developed, much like film in a traditional camera, with ultraviolet light, so that the layout of the microchip is reproduced many times on the same wafer. This work takes place in a specially equipped clean room, or laboratory, that is kept completely free of dust and other impurities. During the miniaturization process, the tiniest speck of dust will ruin the reproduction of the layout onto the wafer.

Next, the wafer is doped with the substances that will give it the necessary conducting properties. Technicians follow the layout, like a road map, when adding these substances. The proper combinations of materials create the various components of the integrated circuit. When this process is complete, the wafer is tested by computerized equipment that can test the many thousands of components in a matter of seconds. Many of the integrated circuits on the wafer will not function properly, and these are marked and discarded. After testing, the wafer is cut up into its individual chips.

The chips are then packaged by placing them in a casing usually made of plastic or ceramic, which also contains metal leads for connecting the microchip into the electronic circuitry of the device for which it will be used. It is this package that is usually referred to as a chip or semiconductor.

Semiconductor process technicians are generally responsible for the fabrication and processing of the semiconductor wafer. Semiconductor development technicians usually assist with the basic design and development of rough sketches of a prototype chip; they may be involved in transferring the layout to the wafer and in assembling and testing the semiconductor. Both types of technicians gather and evaluate data on the semiconductor, wafer, or chip. They must ensure that each step of the process precisely meets test specifications, and also identify flaws and problems in the material and design. Technicians may also assist in designing and building new test equipment, and in communicating test data and production instructions for large-scale manufacture. Technicians may also be responsible for maintaining the equipment and for training operators on its use.