IC manufacturing

The processing of Silicon wafers to produce integrated circuits involves a good deal of chemistry and physics. In order to alter the surface conditions and properties, it is necessary to use both inert and toxic chemicals, specific and unusual conditions, and to manipulate those conditions with both plasma-state elements and with RF (Radio Frequency) energies. Starting with thin, round wafers of silicon crystal, in diameters of 150, 200, and 300mm, the processes described here build up a succession of layers of materials and geometries to produce thousands of electronic devices at tiny sizes, which together function as integrated circuits (ICs). The devices which now occupy the surface of a one-inch square IC would have occupied the better part of a medium-sized room 20 years ago, when all these devices (transistors, resistors, capacitors, and so on) were only available as discreet units. The conditions under which these processes can work to successfully transform the silicon into ICs require an absolute absence of contaminants.

Thus, the process chambers normally operate under vacuum, with elemental, molecular, and other particulate contaminants rigorously controlled. In order to understand these processes, then, we will begin the study of semiconductor processing with an overview of vacuum systems and theory, of gas systems and theory, as applied specifically to these tools, and of clean room processes and procedures