Solid-state image pickup device and a method of manufacturing the same

1. A solid-state image pickup device, comprising:

a silicon layer;

a pixel portion formed in said silicon layer for processing and outputting signal charges obtained by carrying out photoelectric conversion for incident light,

an alignment mark formed in a periphery of said pixel portion and in said silicon layer; and

a contact portion connecting a first electrode within a wiring layer formed on a first surface of said silicon layer, and a second electrode formed on a second surface opposite to said first surface of said silicon layer through an insulating film,

wherein said alignment mark and said contact portion are formed from conductive layers made of the same conductive material and formed within respective holes each extending completely through said silicon layer through respective insulating layers made of the same material, characterized in that

said first electrode within said wiring layer is an uppermost wiring layer, and

a connection element is formed between said contact portion and said first electrode.

2. The solid-state image pickup device according to claim 1 , wherein

said conductive layer is made of silicon doped with an impurity of a conductivity type, and

a silicide layer is formed on a surface of said conductive layer on the side of said first electrode.

3. The solid-state image pickup device according to claim 1 , wherein

said conductive layer is made of a metal.

4. The solid-state image pickup device according to claim 1 , wherein

a silicide layer is formed between said contact portion and said connection element.

5. The solid-state image pickup device according to claim 1 , wherein

said conductive layer is made of silicon doped with an impurity of a conductivity type, and

a silicide layer is formed on a surface of said conductive layer on the side of said first electrode.

6. A method of manufacturing a solid-state image pickup

device, comprising:

forming a first hole in which an alignment mark is intended to be formed, and a second hole in which a contact portion for a pad is intended to be formed from a first surface side of a silicon substrate;

filling a conductive layer in each of said first hole and said second hole through an insulating layer, thereby forming said alignment mark and said contact portion in said first hole and said second hole, respectively;

forming a light receiving portion, in a pixel portion, for photoelectrically converting an incident light to output signal charges corresponding to the incident light, a transistor, in said pixel portion, for reading out the signal charges from said light receiving portion and outputting a signal corresponding to the signal charges, and a transistor, in a peripheral circuit portion, for processing the signal outputted from said pixel portion in said silicon substrate;

forming a first insulating film on said first surface of the silicon substrate, and forming a connection element so as to be connected to said contact portion on said first insulating film;

forming a wiring layer so as to include a first electrode, in a pad portion, connected to said connection element on said first insulating film;

removing a second surface side opposite to the first surface side of said silicon substrate until said contact portion is exposed, and forming a second insulating film on an exposed surface of the remaining silicon substrate; and

forming a second electrode, in said pad portion, so as to be connected to said conductive layer in said second insulating film on the second surface side of said silicon substrate, comprising

said first electrode within said wiring layer is the uppermost wiring layer; and

said connection element between said contact portion and said first electrode is formed.

7. The method of manufacturing a solid-state image pickup device according to claim 6 , wherein

a silicide layer is formed on each of source and drain regions of said transistor in said peripheral circuit portion and at the same time,

a silicide layer is formed on a surface of said conductive layer.

8. The method of manufacturing a solid-state image pickup device according to claim 6 , further comprising:

forming a color filter layer on an optical path of the incident light made incident to said light receiving portion and on said second insulating film; and

forming a condenser lens for guiding the incident light to said light receiving portion on said color filter layer.

9. The method of manufacturing a solid-state image pickup device according to claim 6 , wherein

a silicide layer is formed between said contact portion and said connection element.