Thomas Geßner

Electrical properties of copper films produced by MOCVD

To characterize blanket CVD copper films several analytical tests were carried out. The impurity concentrations were detected by secondary ion mass spectroscopy. Values lower than 0.2 at.% were found. Furthermore some structural properties like grain sizes were investigated using transmission electron microscopy. The grain sizes were determined by TEM dark field images. The model by Mayadas and Shatzkes [1] will be discussed for the explanation of the higher resistivity of CVD deposited copper films compared to the bulk value. It was found that the grain boundaries mainly contribute to this increased resistivity.

Integration of fluidic jet actuators in composite structures

Fluidic Actuated Flow Control (FAFC) has been introduced as a technology that influences the boundary layer by actively blowing air through slots or holes in the aircraft skin or wind turbine rotor blade. Modern wing structures are or will be manufactured using composite materials. In these state of the art systems, AFC actuators are integrated in a hybrid approach. The new idea is to directly integrate the active fluidic elements (such as SJAs and PJAs) and their components in the structure of the airfoil. Consequently, the integration of such fluidic devices must fit the manufacturing process and the material properties of the composite structure. The challenge is to integrate temperature-sensitive active elements and to realize fluidic cavities at the same time. The transducer elements will be provided for the manufacturing steps using roll-to-roll processes. The fluidic parts of the actuators will be manufactured using the MuCell® process that provides on the one hand the defined reproduction of the fluidic structures and, on the other hand, a high light weight index. Based on the first design concept, a demonstrator was developed in order to proof the design approach. The output velocity on the exit was measured using a hot-wire anemometer.

Geometrical optimization of multilevel interconnects using Cu and low- k dielectrics

Abstract A comparison of propagation time and cross-talk for different technology variations was carried out. The calculation of parasitics was based on electrostatic field simulation in two dimensions, which also allows bounds to be obtained for three-dimensional effects such as line crossings in upper levels. The dependence of IC performance on the materials used for metallization was modelled. The simulation results recommend the use of copper and low- k dielectrics as a desirable alternative for aluminum and SiO 2 . In addition to material substitutions, the circuit performance can be improved further by the optimization of the geometrical interconnection parameters such as the interconnect aspect ratio and the interlevel distance for the most critical interconnects. This is demonstrated for an advanced metalization scheme produced by a gap-fill process using encapsulated copper and low- k dielectrics.