Simulation of Tin Plasmas & Theory of Laser Light Absorption
Computer chips are desperately needed in our society. The first step of making computer chips is to bombard slices of silicone with extreme ultraviolet (EUV) light; This is called (nano)lithography. Science is therefore looking for more efficient nanolithography techniques.
I used computer simulations to investigate a new technique of producing EUV light. I looked at the amount of light that is produced, but also at the emission of harmful ions. These results are now being checked in the lab.
In addition, I have done theoretical research into absorption of laser light in a plasma. Plasma electrons in a light field behave differently than is often heard, and this affects the strength of light absorption. By carefully calculating this, I have derived a new formula that better describes light absorption. This result is not only interesting for (future) lithography techniques, but also for nuclear fusion.
My simulations show that EUV production by means of a long light pulse can in principle generate more energy than the current technique. By producing more EUV per drop of tin, computer chips can be made even faster. However, this also produces more high-energy ions, and these can reduce the efficiency of the machine over time; this must be taken into account in practice.
My theoretical research on light absorption shows that the behaviour of plasma electrons in a light field can be taken into account quite easily in calculations of light absorption. The influence of light leads to a simple change of one quantity: the so-called Coulomblogarithm. All in all, we expect: the stronger the light, the less absorption takes place.
If this new technique also proves useful in practice, it could mean a faster way of producing computer chips for the chip industry. And faster production means greater supply and therefore lower prices.
More information on the thesis to follow.