Semiconductor device and manufacturing method thereof

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

• forming columnar electrodes above a first face of a semiconductor chip, the semiconductor chip having the first face and a second face on an opposite side to the first face and including semiconductor elements on the first face;
• providing a first member having an upper surface at a lower location than the columnar electrodes above the first face of the semiconductor chip;
• forming an insulant embedding the columnar electrodes and the first member on the first face;
• and
• polishing the insulant and the columnar electrodes until the first member harder than the columnar electrodes and the insulant is exposed.