INTEGRATED CIRCUITS
Single electronic components are normally soldered (connected by metal) on to a circuit board by their legs. Metal tracks on the board connect the components together. Circuits that require hundreds or thousands of components would be enormous. Modern circuits use integrated circuits, or microchips, in which microscopically small components and the connections between them are built into a wafer of semiconductor material, which is normally silicon. This is why integrated circuits are often called silicon chips. There are thousands of different integrated circuits. Some, such as amplifier chips or timing chips, contain a few dozen components. Others, such as computer processors or memory chips, contain hundreds of thousands or even millions.
The first integrated circuit was built in 1959 in the USA by Texas Instruments. Since then the number of components that can be fitted on to a chip has increased rapidly. An integrated circuit starts life as thin wafer of semiconductor material. The components are built into it by adding and removing layers of semiconductor material, conductors and insulators, using complex chemical and photographic processes.
Picture Credit : Google