Semiconductor device and preparation method thereof

The invention provides a semiconductor device, a first dielectric layer is arranged on a substrate, a plurality of mutually separated first conductive patterns and a barrier layer are arranged in the first dielectric layer, the barrier layer is located on the first conductive patterns, and at least part of the top surface of the barrier layer is exposed out of the first dielectric layer; the metal oxide layer is located on the first dielectric layer and the barrier layer, the second dielectric layer is located on the metal oxide layer, and the multiple conductive columns are arranged in the second dielectric layer in a mutually separated mode and penetrate through the metal oxide layer to make contact with the barrier layer so as to be electrically connected with the first conductive pattern through the barrier layer. The blocking layer can block the metal oxide layer and the first conductive pattern, after the metal oxide layer is formed, the metal oxide layer does not make contact with the first conductive