The present invention relates to a method for forming vias in a semiconductor substrate, including the following steps: (a) providing a semiconductor substrate having a first surface and a second surface; (b) forming a groove on the semiconductor substrate; (c) filling the groove with a conductive metal; (d) removing part of the semiconductor substrate which surrounds the conductive metal, wherein the conductive metal is maintained so as to form an accommodating space between the conductive metal and the semiconductor substrate; and (e) forming an insulating material in the accommodating space. In this way, thicker insulating material can be formed in the accommodating space, and the thickness of the insulating material in the accommodating space is even.