Cold Chemical Lamination—New Bonding Technique of LTCC Green Tapes

Abstract

The low‐temperature co‐fired ceramic (LTCC) technology enables fabrication of sensors, actuators, microfludic devices2 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°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 Rφ standard deviation of sheet resistance σR, variability coefficient of sheet resistance VR, and long‐term stability) are analyzed and compared in this paper. The bonding quality is examined by a scanning electron microscope (SEM).