The technology of electronic devices

The design and manufacture of electronic devices are based on the use of physicochemical processes and a combination of various properties of materials. It is necessary, therefore, to understand thoroughly the processes used and their effects on the properties of the devices and to be able to control the processes with precision.

The great importance of physicochemical research and of the development of the scientific bases of engineering in electronics stems from the dependence of the properties of electronic devices on the presence of doping agents and substances adsorbed on the surfaces of a device’s working elements, as well as the dependence of the properties on gas composition and the degree of rarefaction of the medium surrounding the elements. It is also due to the dependence of the reliability and service life of electronic devices on the degree of stability of the raw materials used and on the controllability of the fabrication technology.

Technological advances often stimulate the development of new areas of application in electronics. Engineering features common to all areas of application of electronics are the requirements—exceptionally high in comparison with other branches of technology—that the electronics industry imposes on the properties of the raw materials used, on the degree of protection provided for the workpieces during production, and on the geometric precision of the fabrication of electronic devices.

Fulfillment of the first of these requirements makes possible the synthesis of ultrapure materials with a structure that has a high degree of perfection and with predetermined physicochemical properties. The development of such materials—which include special composites of single crystals, ceramics, and glasses—and the study of their properties constitute the subject of a special scientific and engineering discipline called electronic materials science.

One of the most acute engineering problems associated with the second requirement is dust control in the gaseous medium in which the most critical fabrication processes take place. In many cases, no more than three dust particles of less than 1 micrometer in diameter are acceptable per cubic meter.

The requirements for geometric precision in the fabrication of electronic devices are exceedingly stringent. Often, the relative error in size cannot exceed 0.001 percent, and the dimensions and relative positions of the elements of integrated circuits must be accurate to hundredths of a micrometer. Such stringency dictates that new, more advanced methods of working with materials be developed, as well as new techniques and equipment for quality control.

Manufacturing processes in electronics require extensive use of the latest methods and technology, which include electron-beam, ultrasonic, and laser processing and welding; photolithography and electron-beam and X-ray lithography; electron-discharge machining; ion implantation; plasma chemistry; molecular epitaxy; electron microscopy; and techniques that employ vacuum devices with a residual gas pressure of as low as 10–13 mm Hg.

Apart from the general aims of increasing labor productivity, the automation of the production of electronic devices through the use of computers is made imperative by a degree of complexity in many manufacturing processes that requires the elimination of subjective human influence. These and other features of the manufacturing processes in electronics have necessitated the creation of a new area of application of machine building—electronic machine building.