Design and fabrication of stencil masks for quantum experimentation

This report takes place in the frame of quantum experimentation. Indeed, the purpose of this project is to pattern quantum structures on a chip where a carbon nanotube device is already deposited. In this specific case, conventional lithography cannot be applied: we therefore explore to what extent stencil lithography can be a solution. Thus, we must determine if it is possible to create stencil masks for quarter wave cavities, transmission lines and four-point probes micropatterning, and what are the dimensions we can aim for. The methodology we elaborated count three main categories: design of stencils, fabrication of stencils, and evaluation of patterned structures. We designed a total of the 47 different stencil structures, fabricated 4 stencil wafers, each with different parameters, and evaluated almost all the functional stencils. In this report, we review all the choices we made, the issues we got and the results we obtained. Our results show us that using stencil lithography seems promising in our case. Although the stencil manufacturing process took much time, we managed to pattern structures of several millimeters long and only of a few tens of micrometers wide. However, additional investigations are still necessary to have a clear idea of the limit dimensions for each of the quantum structures.