Semiconductor device and manufacturing method thereof

The invention discloses a semiconductor device and a manufacturing method thereof. The semiconductor device comprises a substrate, a capacitor structure, a supporting structure and an auxiliary layer. The capacitor structure is arranged on the substrate and comprises a plurality of columnar bottom electrodes, a capacitor dielectric layer and a top electrode layer. The supporting structure is arranged between the adjacent columnar bottom electrodes and comprises a first supporting layer and a second supporting layer which are sequentially arranged from bottom to top. The auxiliary layer is only sandwiched between each columnar bottom electrode and the support structure, and is in direct contact with the side walls of the first support layer, the second support layer and the columnar bottom electrodes. Therefore, through the arrangement of the auxiliary layer, the adhesion between the columnar bottom electrode and the supporting structure is enhanced, and stress buffering is provided, so that a more stable and