Optical lithography: Where will it end?
Optical lithography is one of the most costly and highly leveraged technologies in the complex process of manufacturing integrated circuits (ICs). The leverage comes from the number of IC "chips" that fit on a silicon wafer and the density of circuit functions on the chip. The number of wafer processing steps is unchanged by the number of chips on the wafer. As IC features become smaller, device functionality and speed improve while power consumption decreases. These factors all improve value and reduce the cost per chip. The integrated circuit process is much like a multilayer circuit board, only more complex. Some of the more complex devices like dynamic memory or DRAM contain as many as 20-25 different layers. Any gains in performance or productivity at each layer are multiplied by the number of layers.
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