Image sensor
Provided is an image sensor including a semiconductor substrate having first and second surfaces, transistors on the first surface, first and second lower pad electrodes apart from each other on a first interlayer insulating film covering the transistors, a mold insulating layer on the first and second lower pad electrodes, a first lower electrode inside a first opening passing through the mold insulating layer on the first lower pad electrode, a second lower electrode inside a second opening passing through the mold insulating layer on the second lower pad electrode, a dielectric film and an upper electrode on the first and second lower electrodes, a first contact plug passing through the mold insulating layer and connected to the first lower pad electrode, and a second contact plug passing through the mold insulating layer and connected to the second lower pad electrode.
1. An image sensor comprising:
a semiconductor substrate having a first surface and a second surface;
transistors disposed on the first surface of the semiconductor substrate;
first and second lower pad electrodes spaced apart from each other on a first interlayer insulating film, the first interlayer insulating film covering the transistors;
a mold insulating layer disposed on the first and second lower pad electrodes;
a first lower electrode formed inside a first opening, the first opening passing through the mold insulating layer, and the first lower electrode being on the first lower pad electrode;
a second lower electrode formed inside a second opening, the second opening passing through the mold insulating layer, and the second lower electrode being on the second lower pad electrode;
a first wiring layer located at a vertical level lower than that of the first and second lower pad electrodes;
a second wiring layer located at a vertical level higher than that of the first and second lower pad electrodes;
a dielectric film and an upper electrode disposed on the first lower electrode and the second lower electrode;
a first contact plug passing through the mold insulating layer, the first contact plug being connected to a top surface of the first lower pad electrode; and
a second contact plug passing through the mold insulating layer, the second contact plug being connected to a top surface of the second lower pad electrode,
wherein the second lower pad electrode is not directly connected to the first wiring layer through the second contact plug or any other contact plug, and
the second lower pad electrode is directly connected to the second wiring layer through the second contact plug.
2. The image sensor of claim 1 , wherein a bottom surface of the second lower pad electrode is entirely covered by the first interlayer insulating film.
3. The image sensor of claim 1 , wherein at least one of the transistors is a calibration transistor, and
the second lower pad electrode is connected to an impurity region of the calibration transistor through the second contact plug and the second wiring layer.
4. The image sensor of claim 3 , further comprising:
a lower contact plug passing through the first interlayer insulating film; and
an edge wiring layer disposed on the lower contact plug and located at a vertical level the same as that of the second lower pad electrode,
wherein the second lower pad electrode is not in direct contact with the lower contact plug.
5. The image sensor of claim 4 , wherein the second lower pad electrode is connected to the impurity region of the calibration transistor through the second contact plug, the second wiring layer, the edge wiring layer, and the lower contact plug.
6. The image sensor of claim 1 , wherein the second lower pad electrode comprises:
a main pad portion having a rectangular horizontal cross-section; and
an extension protruding from the main pad portion,
wherein the second contact plug is on a top surface of the extension.
7. The image sensor of claim 1 , wherein a bottom surface of the first lower pad electrode is entirely covered by the first interlayer insulating film.
8. The image sensor of claim 7 , wherein the first lower pad electrode comprises:
a main pad portion having a rectangular horizontal cross-section; and
an extension protruding from the main pad portion,
wherein the first contact plug is on a top surface of the extension.
9. The image sensor of claim 1 , further comprising an upper pad electrode disposed on the upper electrode,
wherein the upper pad electrode comprises a doped semiconductor material.
10. An image sensor comprising:
a semiconductor substrate having a first surface and a second surface;
a photoelectric conversion region formed in the semiconductor substrate;
transistors disposed on the first surface of the semiconductor substrate;
first and second lower pad electrodes spaced apart from each other on a first interlayer insulating film that covers the transistors, the first and second lower pad electrodes each having a main pad portion having a rectangular horizontal cross-section and an extension protruding from the main pad portion;
a plurality of first lower electrodes disposed on the first lower pad electrode;
a plurality of second lower electrodes disposed on the second lower pad electrode;
a dielectric film and an upper electrode sequentially formed on a sidewall and a top surface of each of the plurality of first lower electrodes and a sidewall and a top surface of each of the plurality of second lower electrodes;
a first contact plug located on a top surface of the extension of the first lower pad electrode; and
a second contact plug located on a top surface of the second lower pad electrode.
11. The image sensor of claim 10 , further comprising a mold insulating layer disposed on the first interlayer insulating film and the first and second lower pad electrodes, the mold insulating layer comprising a first opening and a second opening,
wherein each of the plurality of first lower electrodes is inside the first opening of the mold insulating layer,
each of the plurality of first lower electrodes has a cylindrical shape,
each of the plurality of second lower electrodes is inside the second opening of the mold insulating layer, and
each of the plurality of second lower electrodes has a cylindrical shape.
12. The image sensor of claim 11 , wherein the first contact plug and the second contact plug pass through the mold insulating layer.
13. The image sensor of claim 11 , wherein a bottom surface of the second lower pad electrode is entirely in contact with the first interlayer insulating film, and
a bottom surface of the first lower pad electrode is entirely in contact with the first interlayer insulating film.
14. The image sensor of claim 10 , wherein each of the plurality of first lower electrodes and the plurality of second lower electrodes has a pillar shape, and
the dielectric film and the upper electrode cover a sidewall and a top surface of each of the plurality of first lower electrodes and a sidewall and a top surface of each of the plurality of second lower electrodes.
15. An image sensor comprising:
a semiconductor substrate having a first surface and a second surface;
a photoelectric conversion region formed in the semiconductor substrate;
transistors disposed on the first surface of the semiconductor substrate;
first and second lower pad electrodes spaced apart from each other on a first interlayer insulating film, the first interlayer insulating film covering the transistors;
a mold insulating layer disposed on the first and second lower pad electrodes;
a first lower electrode formed inside a first opening, the first opening passing through the mold insulating layer, and the first lower electrode being on the first lower pad electrode and having a cylindrical shape;
a second lower electrode formed inside a second opening, the second opening passing through the mold insulating layer, and the second lower electrode being on the second lower pad electrode and having a cylindrical shape;
a dielectric film and an upper electrode formed on the first lower electrode and the second lower electrode;
an upper pad electrode disposed on the upper electrode, the upper pad electrode comprising a doped semiconductor material;
a second interlayer insulating film covering the mold insulating layer and the upper pad electrode;
first and second contact plugs passing through the mold insulating layer and the second interlayer insulating film, the first and second contact plugs being connected to top surfaces of the first and second lower pad electrodes, respectively;
a first wiring layer disposed on the first interlayer insulating film at a vertical level lower than that of the first and second lower pad electrodes; and
a second wiring layer disposed on the second interlayer insulating film,
wherein at least one of the transistors is a calibration transistor, and
the second lower pad electrode is connected to an impurity region of the calibration transistor through the second contact plug and the second wiring layer.
16. The image sensor of claim 15 , wherein a bottom surface of the second lower pad electrode is entirely covered by the first interlayer insulating film, and
a bottom surface of the first lower pad electrode is entirely covered by the first interlayer insulating film.
17. The image sensor of claim 15 , further comprising:
a lower contact plug passing through the first interlayer insulating film; and
an edge wiring layer disposed on the lower contact plug at a vertical level the same as that of the second lower pad electrode,
wherein the second lower pad electrode is not in direct contact with the lower contact plug.
18. The image sensor of claim 15 , wherein the second lower pad electrode comprises:
a main pad portion having a rectangular horizontal cross-section; and
an extension protruding from the main pad portion,
wherein the second contact plug is on a top surface of the extension.