LTCC lamination process using PMMA fugitive material

Integrated cavities, screen-printed passive components and channels are common parts of 3D micro-fluidic devices fabricated in low temperature co-fired ceramics (LTCC) technology. However, realization of defect-free structures without cracks, sagging of cavities or channels is challenging and strongly influenced by quality of lamination and firing processing conditions. Lamination technique based on incorporation of polymethylmethycrylate (PMMA) sacrificial volume material (SVM) for implementation of large cavities inside LTCC module is presented in this paper. Optimized firing conditions for proper burnout of SVM have been described. Influence of lamination and firing processing conditions are demonstrated in fabrication of 3-dimensional micro-fluidic device. Tested structure contains screen printed interdigital capacitor (IDC) positioned inside large cavity with dimensions 0.23 +/- 0.01 × 5.6 × 11.2 [mm³] for thickness, width and length, respectively. Obtained results show advantages of PMMA incorporation in fabrication of defect-free structures in LTCC technology.