In 1965 Gordon Moore, co-founder of Intel, made an observation that the number of transistors per square inch on integrated circuits doubles approximately every two years since the integrated circuit was invented. His prediction has turned to be uncannily accurate as it had become a driving force in the semiconductor industry for setting long-term goals and targets for research and development.

As the semiconductor industry is racing towards new technology nodes, the fabs are getting a real hard time to imprint the new masks. The reason being simple; Fabs are now reaching the limits of the single exposure 193nm lithography for printing the 20 nm and below, which corresponds to a layout minimum pitch of around 80 nm.

In order to keep up with the Moore’s law, the fabs must adopt lower wavelengths of light or the design must be split into two sets of alternating structures, each more dense than the other but utilizing the resource completely. Not to so say the resource being silicon over here.