A method for manufacturing a semiconductor device comprises the steps of providing a semiconductor body with a main plane of extension, and forming a trench in the semiconductor body from a top side of the semiconductor body in a vertical direction which is perpendicular to the main plane of extension of the semiconductor body. The method further comprises the steps of coating inner walls of the trench with an isolation layer, depositing a metallization layer within the trench, and depositing a passivation layer within the trench such that an inner volume of the trench is free of any material, wherein inner surfaces that are adjacent to the inner volume are treated to be hydrophobic at least in places. Furthermore, a semiconductor device is provided.