Solid state imaging device and method for manufacturing the same

Abstract

A plurality of light receiving elements are arranged in a matrix with uniform space therebetween in a light receiving region defined on a semiconductor substrate. A plurality of read-out electrodes are formed on the semiconductor substrate in an arrangement corresponding to the light receiving elements to read charges generated by the light receiving elements, a light shield film having openings positioned above the light receiving elements is formed to cover the read-out electrodes, first optical waveguides are formed in the openings above the light receiving elements and second optical waveguides are formed on the light shield film. The second optical waveguides are in the form of dots, stripes or a grid when viewed in plan.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view illustrating an enlargement of part of a CCD solid state imaging device according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along the line II-II shown in FIG. 1.

FIGS. 3A to 3E are sectional views illustrating the steps of manufacturing the CCD solid state imaging device according to the first embodiment.

FIG. 4 is a plan view illustrating an enlargement of part of a CCD solid state imaging device according to a second embodiment of the present invention.

FIG. 5 is a plan view illustrating an optical waveguide in the form of a grid.

FIG. 6 is a plan view illustrating an optical waveguide in the form of stripes.

FIG. 7 is a plan view schematically illustrating the structure of a conventional CCD solid state imaging device.

FIG. 8 is a plan view illustrating an enlargement of part of a conventional solid state imaging device including microlenses and optical waveguides.

FIG. 9 is a sectional view taken along the line IX-IX shown in FIG. 8.

FIG. 10 is a view illustrating protrusions generated during the manufacture of the conventional CCD solid state imaging device.

Claims

1. A solid state imaging device including a plurality of light receiving elements arranged in a substrate, the solid state image device comprising: first optical waveguides formed above the light receiving elements; andsecond optical waveguides formed above regions between the light receiving elements.

2. The solid state imaging device of claim 1 further comprising condenser lenses provided in the same arrangement as the light receiving elements and the first optical waveguides when viewed in plan, whereinthe second optical waveguides are positioned below regions between the condenser lenses.

3. The solid state imaging device of claim 1 further comprising light absorbers arranged below the second optical waveguides.

4. The solid state imaging device of claim 1, wherein the second optical waveguides are column-shaped.

5. The solid state imaging device of claim 1, wherein the second optical waveguides are in the form of a grid or stripes when viewed in plan.

6. The solid state imaging device of claim 1 further comprising: charge transfer portions formed in the substrate to be positioned between the light receiving elements;a gate insulating film formed on the charge transfer portions;gate electrodes formed on the gate insulating film;a light shield film covering the gate electrodes and having openings positioned above the light receiving elements; andan insulating film covering the surface of the light shield film and the inside of the openings, whereinthe first optical waveguides are formed in the openings andthe second optical waveguides are formed above the light shield film.

7. A method for manufacturing a solid state imaging device including a plurality of light receiving elements arranged in a substrate, the method comprising the steps of: (a) depositing a first insulating film above the substrate in which the light receiving elements have been formed;(b) forming first openings in the first insulating film to be positioned above the light receiving elements;(c) forming second openings in the first insulating film to be positioned above regions between the light receiving elements; and(d) filling the first openings and the second openings with a second insulating film to form first optical waveguides in the first openings and second optical waveguides in the second openings.

8. The method of claim 7, wherein a SiN film is formed by HDP-CVD as the second insulating film in the step (d).

9. The method of claim 7, wherein in the step (d), the second insulating film is formed to fill the first openings and the second openings and cover the surface of the first insulating film and then part of the second insulating film positioned above the first insulating film is removed.

10. The method of claim 7, wherein the steps (b) and (c) are performed simultaneously.