Electronic power devices have to withstand high mechanical stresses which generate during the operation of high electric powers due to local heating and thermal expansion. The detailed knowledge of the mechanical characteristics of the used components is therefore essential for the design of robust devices. As the size of the used structures often influences the mechanical behavior of materials, the setup of mechanical tests in the dimension of the application is of high interest. In these studies a miniaturized temperature dependent tensile test on polycrystalline copper has been set up. The tested samples had a width of 20 µm and a thickness ranging from 5 µm to 20 µm and therefore represent real structures in power electronic applications. The tensile tests where performed in situ in a scanning electron microscope (SEM) at temperatures up to 400°C. This allows the measurement of stress strain relations with simultaneous observation of the deformation behavior in high magnification. Therefore detailed insights in temperature dependent micromechanical phenomena can be gained. The samples have been generated by electrochemical deposition and lithographic structuring. Further more a substrate etching process in order to generate freestanding samples has been setup. The microstructure of the samples was resolved by electron backscattered diffraction (EBSD). Tensile tests on samples of different thickness where performed at room temperature, 100°C, 200°C, 300°C and 400°C. Mechanical parameters like yield stress, ultimate tensile strength and elongation at fracture have been evaluated from the stress strain relations. The dependencies of the data on temperature, sample thickness and microstructure has been evaluate and compared to literature values of other miniaturized and macroscopic tensile test setups.