Manufacturing method for interconnection having stress-absorbing layer between the semiconductor substrate and the external connection terminal

A manufacturing method for semiconductor device, comprising:

• preparing a semiconductor substrate including a first face and a second face on a side opposite to the first face;
• forming a first electrode on the first face of the semiconductor substrate;
• forming a second electrode having a top face and a rear face on the first face of the semiconductor substrate;
• forming on the first face of the semiconductor substrate an interconnection electrically connected to the first electrode;
• electrically connecting the first electrode to the interconnection by forming an external connection terminal connected to the interconnection on the first face of the semiconductor substrate;
• forming a stress-absorbing layer between the semiconductor substrate and the external connection terminal;
• forming a groove portion having a bottom face including at least part of the rear face of the second electrode, on the second face of the semiconductor substrate;
• forming an insulating film on side wall of the groove portion;
• and
• forming in the groove portion a conductive portion electrically connecting an electronic element to the second electrode.