One of the main components used in superconducting quantum chips is the Josephson junction. Currently when fabricating Josephson junctions, the resistance uniformity at wafer-scale is not optimal. It is also known that an annealing process can alter the junction resistance and with it the qubit frequency. However, laser annealing has only shown to be able to increase the junction resistance. An equally effective and minimally invasive technique to decrease junction resistance is necessary to have full control on frequency
targeting. Thermal annealing in a reducing environment is known to result in a global decrease in junction resistance. To get better control on frequency targeting the techniques could be combined. A die containing not-capped Manhattan type Josephson junctions has been annealed using forming gas at 200°C for 2 minutes, based on a non-linear least squares reciprocal function fit to the data an asymptotic lower bound of 467 μSμm^-2 for the change in conductance per unit area has been found. Smaller junctions with an area
of approximately 0.03 μm² undergo a bigger change in conductance per unit area of around 800 μSμm^-2. Annealing at higher temperatures such as 300 and 400°C results in a decrease of the conductance. There is no substantial change in yield of usable SQUIDs when using a rapid thermal annealing process.

The goal of the research described in this thesis was to investigate the basis of dissipation dilution as well as make it comprehensible. In the written literature we could find that the kinetic energy of an oscillating beam is stored into two types of potential energy~\cite{Kippenberg, Kotthaus}. A dissipative bending component and a conservative component due to elongation.

After this the different types of damping were introduced. Of which structural damping was most important, it is experimentally found to be approximately constant for many materials over a large band of frequencies. The loss tangent and quality factor for this type of damping are both constant. The physical origin of this behaviour isn't really understood. But there have been ideas hinted that it is due to surface imperfections~\cite{Kippenberg}.

To simulate dissipation dilution a spring system has been developed. In this system part of the energy is stored in torsion springs and another part in elongation springs. From this model it is observed that the effective spring constant of the total system depends on the initial strain. At low amounts of strain the spring constant is similar to that of torsion springs while at higher strains it becomes more like the elongation spring model. The quality factor of the beam is found to increase linearly with the strain.