Method of manufacturing semiconductor device

1. A method of manufacturing a semiconductor device comprising:

preparing a semiconductor wafer containing a plurality of semiconductor element sections;

forming a conductive portion by forming holes in an active surface of the semiconductor element sections, forming an insulating film in the holes, and embedding a conductive material which protrudes from the active surface via the insulating film;

forming a first groove in a cutting area provided on a periphery of an element area of an active surface of the semiconductor wafer so as not to pass through the semiconductor wafer;

bonding the semiconductor water and a support body via an adhesive layer;

thinning the semiconductor wafer by grinding a rear surface on an opposite side from the active surface, while maintaining the insulating film not exposed;

forming a second groove in the rear surface so as not to pass through to the first groove on the opposite side;

separating each of the semiconductor element sections to make a plurality of semiconductor chips, by connecting the first groove and the second groove while thinning the semiconductor wafer by isotropic etching from the rear surface of the semiconductor wafer so as to expose the insulating film;

exposing the conductive portion from the insulating film by etching from the rear surface, to form feedthrough electrodes in each of the semiconductor element sections; and,

separating the semiconductor element sections into individual pieces by peeling the plurality of semiconductor chips off from the support body.

2. A method of manufacturing a semiconductor device according to claim 1 , wherein the isotropic etching is spin etching in which an etching liquid is dispensed onto the rear surface of the semiconductor wafer while the semiconductor wafer is being rotated.

3. A method of manufacturing a semiconductor device according to claim 1 , wherein a width of the second groove is narrower than a width of the first groove.

4. A method of manufacturing a semiconductor device according to claim 3 , further comprising:

forming a resin layer by embedding a resin in the first groove after the first groove is formed;

extending the second groove to the resin layer, while thinning the semiconductor wafer by the isotropic etching; and

cutting the resin layer to make a plurality of semiconductor chips; and

peeling the plurality of semiconductor chips off from the support body.

5. A method of manufacturing a semiconductor device according to claim 1 , wherein, the support body is translucent.

6. A method of manufacturing a semiconductor device according to claim 5 , wherein, adhesion in the adhesive layer is reduced by ultraviolet light irradiation.