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 via collar along sidewalls of a first portion of a trench over the polymer layer, and forming a second portion of the trench within the polymer layer. The method also includes forming an oxide liner in the trench lining sidewalls of the via collar and sidewalls of the second portion of the trench, depositing a metallic filler in the trench to form a via, and forming a metal cap layer over the via collar and the metallic filler. The method further includes removing a portion of the metal cap layer to form a via cap, and removing the polymer layer such that the via is supported only on a bottom thereof by the substrate. An exemplary structure formed by the disclosed method is also disclosed.