Development of handling- and alignment tools for flexible substrates
Sensors and integrated systems are often designed as multilayer systems. In different process steps these layers are represented by flexible substrates. Also thin foils of silicon or metals are used, which are very sensitive to mechanical loads. Thus vacuum chucks for handling of sensitive flexible substrates were developed and manufactured in this research. The use of precise chucks allows the planarization of the substrates down to 1 µm surface planarity. For alignment of substrates to each other alignment marks or functional structures onto the substates are used. For integration of multilayer stacks two or more chucked substrates need to be aligned. In most applications the x- and y- degree of freedom and rotation rot-z have to be aligned. The alignment movement is done by actuators, supported by flexure hinges for chuck guidance. The fixation technology depends on the substrate materials and structures applicated on the substrates. Adhesive bonding and soldering processes and devices are integrated into the alignment tools. A variety of tools for handling and alignment of flexible substrates were developed in this work to realize the different process steps of multilayer system integration with overlay accuracies down to 1 µm.