Optimization of cavity fabrication for micro-fluidic systems

Processing parameters for an optimized fabrication of micro structures with dimensions ranging from 20 mum to 4 mm channel width and up to 2 mm height providing height/width aspect ratios of 10/1 have been investigated for 3 different LTCC-tapes (low temperature co-fired ceramics). The fabrication process is based on an optimized NdYAG-laser machining process and an adapted isostatic single step lamination method where a remarkable reduction of recommended lamination pressure is conducted successfully, in order to minimize distortions of channel geometry but still providing tightness of laminated LTCC-layers. Different procedures have been tested to improve channel geometry. Consequently different tape-compatible SVM (sacrificial volume materials) have been employed, including liquids working as fillers and adhesives, respectively. The preprocessed structures have been fired in accordance with TGA-optimized (thermo gravimetric analysis) firing profiles which provide a residue-free burnout. This paper summarizes the influence of processing parameters on the final dimensions of various test channel devices.