Structuration of thin bridge and cantilever structures in thick-film technology using mineral sacrificial materials

Thick-film and LTCC (Low Temperature Cofired Ceramic) technologies find increasing use in meso-scale sensors, actuators and related devices that feature excellent dimensional, thermal and chemical stability at moderate cost. While several materials and processes allow fabrication of structures such as channels, membranes and relatively short bridges, obtaining slender bridges and cantilevers with good shape control for applications such as microforce sensors has hitherto remained a challenging task. This work presents techniques based on mineral sacrificial materials that allow fabrication of such intricate structures in thick-film technology, and are also applicable to LTCC. Aspects such as optimal sacrificial materials, paste formulation, structure design and final chemical etching are addressed, with the aim of obtaining reproducible structures.