Image sensor device

1. An image sensor device comprising:

a substrate in which a pad area and a circuit area adjacent to the pad area are defined, the substrate including a first surface and a second surface and being configured to have first conductive impurities;

a pad disposed at the first surface of the substrate in the pad area; and

an impurity area formed to overlap with the pad in a first direction in a lower region of the pad, and formed in a partial region of the substrate in the pad area, the impurity area being configured to have second conductive impurities different from the first conductive impurities,

wherein the substrate formed in the circuit area and the impurity area formed in the pad area are in contact with each other by a boundary area.

2. The image sensor device according to claim 1 , further comprising:

a conductive film disposed at the first surface of the substrate to cover a top surface of the substrate at a lower portion of the pad.

3. The image sensor device according to claim 2 , wherein the conductive film is formed to be larger than the pad in a second direction.

4. The image sensor device according to claim 2 , wherein the conductive film is formed in a trench exposing a plurality of areas of the substrate.

5. The image sensor device according to claim 4 , wherein the pad is formed along a top surface and a side surface of the conductive film.

6. The image sensor device according to claim 2 , further comprising:

a through silicon via disposed at one side of the substrate and being configured to penetrate the substrate in the first direction.

7. The image sensor device according to claim 6 , wherein the through silicon via is electrically coupled to the pad through the conductive film.

8. The image sensor device according to claim 1 , wherein the impurity area is formed as a stacked structure of a plurality of impurity layers including the second conductive impurities.

9. The image sensor device according to claim 8 , wherein

at least one of the plurality of impurity layers is formed as a deep well.

10. The image sensor device according to claim 8 , wherein the plurality of impurity layers is formed to have a same dimension in a second direction.

11. The image sensor device according to claim 8 , wherein the plurality of impurity layers is formed to be larger than the pad in a second direction.

12. The image sensor device according to claim 8 , wherein

at least one of the plurality of impurity layers is formed by implanting the second conductive impurities through the second surface in an impurity implantation process for implanting impurities into a circuit area.

13. The image sensor device according to claim 8 , wherein

at least one of the plurality of impurity layers is formed by implanting the second conductive impurities through the first surface in an impurity implantation process for implanting impurities into a pixel area.

14. The image sensor device according to claim 1 , wherein the impurity area includes:

a first impurity layer formed in the substrate; and

a second impurity layer stacked over the first impurity layer, and configured to have the same conductive impurities as those of the first impurity layer.

15. The image sensor device according to claim 14 , wherein the impurity area further includes:

a third impurity layer stacked over the second impurity layer, and configured to have the same conductive impurities as those of the second impurity layer.

16. The image sensor device according to claim 1 , wherein:

a first well bias is applied to the substrate; and

a second well bias having a voltage level different from that of the first well bias is applied to the impurity area.

17. The image sensor device according to claim 1 , wherein:

a first well bias is applied to the substrate; and

a second well bias having a voltage level different from that of the first well bias is applied to the impurity area.