Solid-state imaging device, fabrication method for the same, and electronic apparatus

Inactive Publication Date: 2010-09-09
SONY CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0012]The present invention has been made in view of the above circumstances. Accordingly, there is a need for a solid-state imaging device which efficiently shields a floating diffusion from light and thus provides images with improved quality. There is also a need for an electronic apparatus using the solid-state imaging device.
[0015]In a solid-state imaging device according to an embodiment of the present invention, the floating diffusion is shielded from light by the light-shielding film constituted by the bottom wiring layer. The bottom wiring layer is disposed at a position lower than the multi-wiring layer and close to the upper surface of the substrate. Thus, the light-shielding film constituted by the bottom wiring layer can prevent leakage of light into the floating diffusion.
[0019]According to an embodiment of the present invention, there is provided for a solid-state imaging device which suppresses degradation of image quality caused by noise and for an electronic apparatus using the solid-state imaging device.

Problems solved by technology

On the other hand, photoelectric conversion also occurs in the floating diffusion if it receives light while reading signal charge transferred from the photodetector, which results in noise.
However, since pixels are formed using CMOS processes as in the case of the other peripheral circuits, the wiring layers may not be disposed so as to be immediately above the floating diffusion, as compared to the case of a CCD solid-state imaging device.
Thus, it is not possible to decrease the distance between the wiring layers constituting a light-shielding film and a floating diffusion and to prevent light leakage into the floating diffusion.
However, to form the gate electrode film in a multilayer structure, the gate electrode film is made of silicide, which leads to complicated fabrication processes.
In addition, it is difficult to form a small aperture for a contact region due to unevenness of the gate electrode.
Moreover, interference between the gate electrode layers due to a large parasitic capacitance between the gate electrode layers is also a matter of concern.
This allows light to travel between the light-shielding film and the floating diffusion, resulting in insufficient light shielding performance.

Method used

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  • Solid-state imaging device, fabrication method for the same, and electronic apparatus
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  • Solid-state imaging device, fabrication method for the same, and electronic apparatus

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Experimental program
Comparison scheme
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first embodiment

1. First Embodiment

Solid-State Imaging Device

[1.1 Overall Configuration of Solid-State Imaging Device]

[0042]FIG. 1 is a block diagram schematically illustrating an overall configuration of a solid-state imaging device according to the first embodiment of the present invention.

[0043]A solid-state imaging device 1 according to the present embodiment includes a pixel section 3 composed of a plurality of pixels 2 arranged on a substrate 11 formed of silicon, a vertical drive circuit 4, column signal processing circuits 5, a horizontal drive circuit 6, an output circuit 7, and a control circuit 8.

[0044]The pixels 2 are each composed of a photodetector composed of a photodiode and a plurality of MOS (metal oxide semiconductor) transistors and are arranged in a regular two-dimensional array on the substrate 11. The MOS transistors constituting the pixels 2 may be composed of four MOS transistors including a transfer transistor, a reset transistor, a selection transistor, and an amplificati...

second embodiment

2. Second Embodiment

Solid-State Imaging Device

[0093]In the following, a solid-state imaging device according to a second embodiment of the present invention will be described. FIG. 10 is a plan view illustrating a single pixel in the solid-state imaging device 35 according to the second embodiment of the present invention. FIG. 11 is a cross sectional view taken along line XI-XI′. The overall configuration of the solid-state imaging device 35 in the present embodiment is similar to that of the solid-state imaging device 1 illustrated in FIG. 1, and the description thereof will be omitted. The solid-state imaging device 35 in the present embodiment has pixels 2 configured similarly to the pixels 2 in the first embodiment illustrated in FIG. 4, and thus the description thereof will be omitted. In FIG. 10 and FIG. 11, the same reference numerals are used to refer to the same or corresponding components as those shown in FIG. 2 and FIG. 3, respectively, and the description of the compon...

third embodiment

3. Third Embodiment

Solid-State Imaging Device

[0100]In the following, a solid-state imaging device according to a third embodiment of the present invention will be described.

[0101]FIG. 12 is a schematic cross-sectional view of a solid-state imaging device 45 according to the third embodiment of the present invention. The overall configuration of the solid-state imaging device 45 is similar to that of the solid-state imaging device 1 in the first embodiment illustrated in FIG. 1, and thus the description thereof will be omitted. In addition, in the solid-state imaging device 45, the planar layout and circuit configuration of a single pixel are similar to those in the first embodiment illustrated in FIG. 2 and FIG. 4, and the description thereof will be omitted. In FIG. 12, the same reference numerals are used to refer to the same or corresponding components as those shown in FIG. 3, and the description of the components will be omitted.

[3.1 Configurations of Main Components]

[0102]In t...

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Abstract

A solid-state imaging device includes a photodetector which is formed on a substrate and is configured to generate signal charge by photoelectric conversion, a floating diffusion configured to receive the signal charge generated by the photodetector, a plurality of MOS transistors including a transfer transistor that transfers the signal charge to the floating diffusion and an amplification transistor that outputs an pixel signal corresponding to a potential of the floating diffusion, a multi-wiring layer which is formed in a layer higher than the substrate and is composed of a plurality of wiring layers electrically connected to the MOS transistors via contact portions, and a light-shielding film that is constituted by a bottom wiring layer disposed in a layer higher than the substrate and lower than the multi-wiring layer.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to solid-state imaging devices. In particular, the present invention relates to CMOS solid-state imaging devices which transfer signal charge to floating diffusions, and methods for fabricating the solid-state imaging devices. The present invention also relates to electronic apparatuses employing the solid-state imaging devices.[0003]2. Description of the Related Art[0004]Solid-state imaging devices are generally classified into CCD (charge coupled devices) solid-state imaging devices and CMOS (complementary metal oxide semiconductor) solid-state imaging devices. In a CCD solid-state imaging device, a high drive voltage is necessary to transfer signal charge, and a high supply voltage is necessary compared to a CMOS solid-state imaging device. Thus, CMOS solid-state imaging devices are more advantageous than CCD solid-state imaging devices in view of power consumption.[0005]Thus, CMOS solid...

Claims

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Application Information

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IPC IPC(8): H04N5/335H01L31/18H04N5/228H01L27/14H01L27/146
CPCH01L27/14603H01L27/14609H01L27/14623H01L27/14689H01L27/14636H01L27/14638H01L27/14687H01L27/14632
InventorTAURA, TADAYUKI
OwnerSONY CORP