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New chemistry to extend the Moore’s Law

The making of a chip is an extremely sophisticated manufacturing process. The basic point, in a nutshell, is to position on a silicon wafer the right atoms in the right places to make transistors, resistors and connections among them. Doing this requires a series of steps each one finely tuned to the previous one. To make sure that you are positioning the atoms at the right place on the wafer you create a mask that protect those areas on the wafer where there shouldn’t be any deposition of atoms, a process that takes place by diffusing a gas over the surface. 
The masking is obtained through photoresists, a layer that is covering the whole wafer and that is selectively removed in those places where one wants the gas to hit the wafer. To remove the wafer in just the right spots one uses a sort of photographic process: you illuminate the photoresist and that changes its characteristics becoming soluble to special solvents. By rinsing the wafer in the solvent one removes the photoresist and exposes the underline wafer that can now be affected by the gas.
The exposure of the photoresist to light is made by illuminating a mask (produced by a computer) having the details magnified. A focalisation of the light beam shrinks the details to the desired scale. The shrinking depends on the wavelength of the light beam being uses, the shorter the wavelength the smaller the details that can be illuminated on the photoresists.  For chip manufacturing the light beam is made by ultraviolet light, in the wavelength range of 248-193 nm. This wavelength is too "long" to scale down to the 10nm of the next chip generation and engineers have to move to extreme ultra violet light (EUV) in the wavelength of 13.5nm.
The problem is that present photoresists are not sensitive to that short wavelength, hence the need to find newer photoresists. Although it might seem strange, scientists so not have a complete understanding on how a photoresists really works and this is a stumbling block in progressing any further.
This is where this news come in. Scientists at Berkeley, teaming up with engineers at Intel, have come up with a new type of photoresist (in short – resist) and in order to do that they have reached a much better understanding on what is a resist and how the fundamental chemistry processes work.
The new resist combines two already used resists to achieve better sensitivity to light (hence being responsive to the shorter wavelength) and better mechanical stability (which is essential as you shrink size). Actually one of the resist had very good sensitivity but low mechanical stability whilst the other had the required mechanical stability (cross-linking) but poor light sensitivity. By understanding the fundamental chemistry the team has been able to capitalise from the strength of each.
They expect to see the new resist being used in the manufacturing process as early as 2017.

About Roberto Saracco

Roberto Saracco fell in love with technology and its implications long time ago. His background is in math and computer science. Until April 2017 he led the EIT Digital Italian Node and then was head of the Industrial Doctoral School of EIT Digital up to September 2018. Previously, up to December 2011 he was the Director of the Telecom Italia Future Centre in Venice, looking at the interplay of technology evolution, economics and society. At the turn of the century he led a World Bank-Infodev project to stimulate entrepreneurship in Latin America. He is a senior member of IEEE where he leads the New Initiative Committee and co-chairs the Digital Reality Initiative. He is a member of the IEEE in 2050 Ad Hoc Committee. He teaches a Master course on Technology Forecasting and Market impact at the University of Trento. He has published over 100 papers in journals and magazines and 14 books.