Semiconductor device and semiconductor device manufacturing method

This application is a Divisional of co-pending application Ser. No. 11/783,839, filed on Apr. 12, 2007, the entire contents of which are hereby incorporated by reference and for which priority is claimed under 35 U.S.C. § 120, and this application claims priority of Japanese Application No. 2006-112354, filed Apr. 14, 2006, under 35 U.S.C. § 119; the entire contents of all are hereby incorporated by reference.

1. Field of the Invention

The present invention relates to a semiconductor device and a semiconductor device manufacturing method and, more particularly, a semiconductor device which is suitable for a metal wiring-stacked structure used for miniaturization of a sensor, high-speed drive, Logic integration, or the like, whose converging effect for converging a light to a photoelectric converting portion is high and whose sensitivity is good, and a semiconductor device manufacturing method.

2. Description of Related Art

As the semiconductor device in the related art, for example, there is a solid state imaging device having the structure shown in FIG. 5. A solid state imaging device 1 has a photoelectric converting portion 2A in which a photodiode 3a is formed on a substrate 3, a charge transferring portion 2B having a charge transfer electrode 4 above the charge transfer channel 5, and a microlens 6 formed on a surface on the light receiving side of the solid state imaging device 1. The solid state imaging device 1 has such an optical waveguide structure that an irradiation light is converged by the microlens 6, passed through a columnar translucent film 7 formed below the microlens 6, and received by the photodiode 3a (see JP-A-2005-101090, for example).

By the way, since the metal wiring-stacked structure is needed in the case of sensor miniaturization, high-speed drive, Logic integration, or the like, the layers of the solid state imaging device 1 should be designed largely. However, in case a thickness of the upper layer on the substrate 3 is increased, it was difficult to form the translucent film 7 acting as an optical waveguide member long in the stacking direction. Also, when the translucent film 7 should be formed long in the stacking direction, a cavity called a void might be easily generated in an inside of the translucent film 7.

An object of an illustrative, non-limiting embodiment of the invention is to provide a semiconductor device which is suitable for a solid state imaging device with a layered structure, whose converging effect for converging a light to a photoelectric converting portion is high, and whose sensitivity is good, and a semiconductor device manufacturing method.

The above object of the present invention can be achieved by following configurations.

(1) A semiconductor device comprising: a substrate; a photoelectric converting portion; and a plurality of optical waveguide portions stacked above the photoelectric conversion portion, each of the plurality of optical waveguide portions comprising a translucent material and being shaped in a taper.
(2) The semiconductor device as described in (1) above, wherein each of the plurality of optical waveguide portions has a sectional area reducing gradually toward the substrate.
(3) A method of manufacturing a semiconductor device comprising a substrate and a photoelectric converting portion, the method comprising stacking a plurality of layers above the photoelectric converting portion, the each of the plurality of layers comprising a wiring portion, an interlayer insulating film, and a tapered optical waveguide portion comprising a translucent material.
(4) The method of manufacturing a semiconductor device as described in (3) above, wherein the tapered optical waveguide portion in each of the plurality of layers has a sectional area reducing gradually toward the substrate.
(5) The method of manufacturing a semiconductor device as described in (3) or (4) above, wherein the optical waveguide portion in each of the plurality of layers is formed by: patterning and etching the interlayer insulating film to make an opening in the interlayer insulating film; and embedding the translucent material into the opening.