Method of manufacturing solid image pickup apparatus
View Patent ↗A first gate electrode and a second gate electrode are formed on a semiconductor substrate, and then a resist pattern is formed so as to selectively leave open a portion including an overlap between the first and second gate electrodes. Next, the overlap between the gate electrodes is removed through isotropic etching. Etching is carried out at this time by an amount within a range of 140% to 200% of the film thickness of the second gate electrode. Next, a normal inter-layer insulating film and light-shielding film are formed. It is possible to eliminate the overlap between the gate electrodes adjacent to an opening of the light-shielding film, suppress the height of the light-shielding film at that portion, reduce shading for the light condensed by a lens and thereby improve the light condensing efficiency of the lens.
1. A method of manufacturing a photoelectric solid image pickup apparatus, said method comprising:
forming a semiconductor substrate comprising a plurality of light-receiving areas and at least one transfer area;
forming an insulating film on said semiconductor substrate;
forming a first electrode on said insulating film;
forming a second electrode on said semiconductor substrate, the second electrode overlapping but being electrically insulated from the first electrode; and
removing all the portion of the second electrode overlapping the first electrode.
2. The method of manufacturing a photoelectric solid image pickup apparatus according to claim 1 , wherein when the portion of the second electrode overlapping the first electrode is removed, a first portion of the second electrode overlapping the first electrode is removed using a first resist pattern with a first opening over the second electrode, then a second portion of the second electrode is removed using a second resist pattern with a second opening over the second electrode.
3. The method of manufacturing a photoelectric solid image pickup apparatus according to claim 1 , wherein the portion of the second electrode overlapping the first electrode is removed by isotropic etching.
4. The method of manufacturing a photoelectric solid image pickup apparatus according to claim 1 , wherein when the second electrode is formed on said semiconductor substrate, an inter-layer insulating film is formed between the first electrode and the second electrode.
5. The method of manufacturing a photoelectric solid image pickup apparatus according to claim 4 , wherein in removing the second electrode, the selection ratio between the inter-layer insulating film and the second electrode is 1:100 or higher.
6. The method of manufacturing a photoelectric solid image pickup apparatus according to claim 2 , wherein the first opening of the first resist pattern is located over the light receiving area and the second opening of the second resist pattern is located over the portion of the second electrode overlapping the first electrode.
7. The method of manufacturing a photoelectric solid image pickup apparatus according to claim 2 , wherein the first opening of the first resist pattern is located over the portion of the second electrode overlapping the first electrode and the second opening of the second resist pattern is located over the light receiving area.
8. The method of manufacturing a photoelectric solid image pickup apparatus according to claim 2 , wherein the first removed portion of the second electrode is larger than the first opening.
9. The method of manufacturing a photoelectric solid image pickup apparatus according to claim 2 , wherein the second removed portion of the second electrode is larger than the first opening.
10. The method of manufacturing a photoelectric solid image pickup apparatus according to claim 1 , further comprising forming a normal inter-layer insulating film on the first electrode, the second electrode, and the light-receiving area.
11. The method of manufacturing a photoelectric solid image pickup apparatus according to claim 10 , further comprising forming a light-shielding film on the normal inter-layer insulating film over the first and second electrodes.
12. The method of manufacturing a photoelectric solid image pickup apparatus according to claim 11 , further comprising forming a transparent resin on the light-shielding film.
13. The method of manufacturing a photoelectric solid image pickup apparatus according to claim 11 , further comprising forming a color resin on the light-shielding film.
14. The method of manufacturing a photoelectric solid image pickup apparatus according to claim 1 , further comprising forming a lens on the semiconductor substrate.