Self-supported MEMS structure and method for its formation are disclosed. An exemplary method includes forming a polymer layer over a MEMS plate over a substrate, forming a trench over the MEMS plate, forming an oxide liner in the trench on sidewalls of the trench, forming a metal liner over the oxide liner in the trench, and depositing a metallic filler in the trench to form a via. The method further includes removing the polymer layer such that the via and the MEMS plate form the self-supported MEMS structure, where the oxide liner provides mechanical rigidity for the metallic filler of the via. An exemplary structure formed by the disclosed method is also disclosed.