Abstract: A MEMS transducing apparatus includes a substrate, a conductive pad, a stacked structure of a transducing device, a first polymer layer, a second polymer layer and a third polymer layer. An upper cavity is formed through the substrate. The conductive pad is formed on a first surface of the substrate to cover a first opening of the upper cavity. The stacked structure of the transducing device is formed on the conductive pad. The first polymer layer is formed on the first surface of the substrate. A lower cavity is formed through the first polymer layer. The stacked structure of the transducing device is exposed within the lower cavity. The third polymer layer is formed on a second surface of the substrate to cover a second opening of the upper cavity. The second polymer layer is formed on the first polymer layer to cover a third opening of the lower cavity.