The main process begins with electrical engineers designing the circuit and defining its functions, and specifying the signals, inputs/outputs and voltages needed.
The wafers are then exposed to short-wave ultraviolet light and the unexposed areas are thus etched away and cleaned.
These steps are often repeated many hundreds of times, depending on the complexity of the desired circuit and its connections.
New processes to accomplish each of these steps with better resolution and in improved ways emerge every year, with the result of constantly changing technology in the wafer fabrication industry.
New technologies result in denser packing of minuscule surface features such as transistors and micro-electro-mechanical systems (MEMS).