Congress contributions

This work investigates the influence of a structured chip surface on the propagation of a self-sustaining reaction that is aimed to be used as heat source for chip assembly. A silicon (100) surface was structured by a combination of thermal oxidation and dry and wet etching to obtain line structures with height lesser than 1 µm. To ensure reaction of 5 µm thick Al/Ni multilayers, 1 µm of SiO2 is used as thermal insulator. Different widths of lines and valleys, with a ratio of 1:1, were processed. Width values were chosen to be 30 µm, 50 µm and 80 µm. Bilayer thickness of 50 nm with a 50/50 at% of Al/Ni were deposited using magnetron sputtering. By using focused ion beam with integrated scanning electron microscope and X-ray diffractometer the samples were analyzed prior to reaction. Velocity and temperature were measured with high-speed camera and high-speed pyrometer. Variations in reaction speed depending on the structure width were recorded and analyzed in perspective of the influence of the additional inclined reaction path. Calculation of the extended reaction paths and their influence on the reaction speed between the structures was performed. The results show that the additional distance has only a low influence on the velocity. Different reasons were identified, but it was not possible to determine the main cause. It was possible to slow down the reaction and keeping the temperature over 350 ˚C for over 500 ms, which provides enough energy to melt solders. The influence of smaller structures can be applied to bonding applications with reactive multilayers.

In the forthgoing work on a device that enables subatomic resolved highly reproducible positioning, a first prototype is here presented. The entire positioning system including the actuator, sensor and guiding mechanism, is realized as a micro-electro-mechanical system (MEMS) on chip level, based on silicon-on-insulator (SOI) technology. A modular printed circuit board acts as the mechanical as well as the electrical contacting interface for the silicon chip. First variants of a linear positioning system comprising axisymmetric double parallel crank structure are investigated. Pivot joints as flexure hinges with concentrated compliance are deployed. These hinges show minimal rotational axis displacement for small angles of deflection, thus ensuring smallest deviations to a straight-line path of the linear guiding mechanism. An electrostatic comb actuator transmits forces contactless to minimize over constraints. A measuring bridge in differential mode utilizes the same comb structures to measure the table position based on the capacitance change. Estimating the position resolution, limited by the resolution of the capacitive sensor, a measurable step width below 50 pm can be expected. In further steps, the device will be a platform to be equipped with a lattice-scale-based position measurement system according to achieve an even higher resolution and reproducibility.

A technical methodology of fabrication of hierarchically scaled multitude graphene nanogratings with varying pitches ranging from the micrometer down to sub 40 nm scale combined with sub 10 nm step heights on 4H and 6H semi-insulating SiC for length scale measurements is proposed. The nanogratings were fabricated using electron-beam lithography combined with dry etching of graphene, incorporating a standard semiconductor processing technology. A scientific evaluation of critical dimension, etching step heights, and surface characterization of graphene nanograting on both polytypes were compared and evaluated.