Semiconductor device having a through electrode and method of manufacturing the same
A semiconductor device according to an embodiment includes a semiconductor layer having a first plane and a second plane, an insulating layer provided in the first plane side of the semiconductor layer, a metal layer provided on or above the insulating layer, and a through electrode penetrating through the semiconductor layer and in contact with the metal layer. When a width of the through electrode in the first plane is a first width, a width of the through electrode in an intermediate plane between the first plane and the second plane is a second width, and a width of the metal layer is a third width, a first difference between the second width and the first width is larger than a second difference between the third width and the first width.
1. A method of manufacturing a semiconductor device, comprising:
forming a groove and a protrusion having a first width in a first plane of a semiconductor layer having the first plane and a second plane;
filling the groove with an insulating layer;
forming a metal layer on the protrusion;
forming an opening portion extending from the second plane to the metal layer through the semiconductor layer, the opening portion having a second width larger than the first width in an intermediate plane between the first plane and the second plane, the protrusion being removed during the forming of the opening portion; and
filling the opening portion with metal to form a through electrode,
wherein, in a view perpendicular to the first plane, the metal layer is positioned over the protrusion, a width of the metal layer is larger than the first width, and the width of the metal layer is smaller than the second width.
2. The method of manufacturing a semiconductor device according to claim 1 , further comprising:
forming an insulating film on a sidewall of the opening portion after the forming of the opening portion and before the filling of the opening portion with the metal.
3. The method of manufacturing a semiconductor device according to claim 1 , wherein the semiconductor layer is made of silicon.
4. The method of manufacturing a semiconductor device according to claim 1 , wherein the insulating layer is made of silicon oxide.
5. The method of manufacturing a semiconductor device according to claim 1 , further comprising:
forming a polysilicon layer between the metal layer and the protrusion.
6. The method of manufacturing a semiconductor device according to claim 1 , wherein the opening portion is formed by dry etching.
7. The method of manufacturing a semiconductor device according to claim 1 , wherein a thickness of the semiconductor layer is equal to or larger than 30 μm.