Semiconductor device and manufacturing method thereof

A method of manufacturing a semiconductor device, comprising the steps of:

• forming an epitaxial layer on an upper surface of a semiconductor substrate having, on its principal surface, a first region for forming a circuit element and a plurality of second regions disposed so as to be equally spaced apart from the first region in a periphery of the first region;
• forming the circuit element on the epitaxial layer in the first region;
• forming step parts on boundaries between the first region and the second regions in the epitaxial layer;
• forming via holes that reach the semiconductor substrate from a surface in the second regions of the epitaxial layer, forming isolation trenches that reach the semiconductor substrate from the step parts, and forming through electrodes made of metal in the via holes;
• forming connection for electrically connecting electrodes of the circuit element to the through electrodes on a surface of the epitaxial layer, and improving adhesion to the step parts by forming a resin layer which integrally supports the first region and the second regions on the surface of the epitaxial layer;
• and
• reducing a thickness of the semiconductor substrate by grinding the substrate from its rear surface, exposing the through electrodes and the isolation trenches from rear surfaces of the second regions, electrically separating the semiconductor substrate in the first region from the semiconductor substrate in the second regions, and forming external connection electrodes made of the semiconductor substrate in the second regions.