Optimization of Fluidic Microchannel Manufacturing Processes in Low Temperature Co-Fired Ceramic Substrates

Abstract

The processing of starch powder and polymer based sacrificial layer for fabrication of microfluidic structures in low temperature co-fired ceramics (LTCC) is described in the paper. Sacrificial volume material (SVM) was placed into the channel of LTCC sheets to avoid sagging by supporting embedded, three-dimensional structures such as channels, cavities during firing. Sagging of laminated structures is a common problem in the processing of the LTCC. A series of experiments were carried out for different lamination schemes which affect the quality of LTCC sheets. Samples were tested by an acoustic microscope to reveal the internal inhomogeneities and delaminations. As a consequence of burnout, the increased fraction of evolving gases from SVM requires an adequate adaptation of the firing process to provide a residue-free burnout without damaging the structure. Using thermal analysis the intensity of the evaporating gases was determined during co-firing. Based on these results, the modification of the heating profile could be done. It is proposed that the fabrication of embedded structures in a multi-layer LTCC platform could be achieved by controlling SVM burnout with a modified heating profile. Using this approach, fabrication of embedded channels in LTCC substrate is demonstrated.