Cold Chemical Lamination-New Bonding Technique of LTCC Green Tapes

The low-temperature co-fired ceramic (LTCC) technology enables fabrication of sensors, actuators, microfludic devices 2 and fuel cells. The structures consist of screen-printed components, gas/liquid channels, reactive chambers and mixers. The lamination process determines the quality of such devices. Thermo-compression is the most popular bonding method. The LTCC green tapes are joined together at high temperature (up to 80 degrees C) and high pressure (up to 30 MPa) for 2 to 15 minutes. The method allows good encapsulation of the LTCC structures, but the channels geometry is strongly affected by elevated temperature and pressure. Cold Chemical Lamination (CCL) is a new LTCC green tapes bonding technique, which allows for fabrication of 3D modules. A solvent-based method is used in the CCL lamination instead of the thermo-compression process. A special liquid agent is screen-printed on the green tape in the CCL method. The liquid melts the tape surface. Then the tapes are stacked and compressed at room temperature by a printing roll. The influence of the CCL and the thermo-compression methods on the chamber's geometry quality as well as basic electrical properties of screen-printed resistors (sheet resistance R-phi standard deviation of sheet resistance sigma(R), variability coefficient of sheet resistance V-R, and long-term stability) are analyzed and compared in this paper. The bonding quality is examined by a scanning electron microscope (SEM).