JPH0214570A - Solid-state image pick-up device and manufacture thereof - Google Patents

Abstract

PURPOSE:To sharply reduce a smear phenomenon and improve picture quality by forming a photoreflective or photoabsorptive film on the side of a charge transfer means. CONSTITUTION:Since slanting incident light 11 is reflected or absorbed by a shielding film 10 while not proceeding toward a transfer channel 5 of vertical transfer CCD(VCCD). In this case, the shielding film 10 is not required to be completely photoreflective or photoabsorptive, because, for instance, when transmittivity is 10%, a smear due to such slanting incident light is to be reduced to 10% resulting in sharp reduction of a smear phenomenon and practically coming not much to question. Further, provided that the shielding film 10 is an insulating film, it can be directly formed on the side of the VCCD transfer electrode 4, and still provided that the shielding film is a conductive film, the insulating film 6 such as a thermal oxide film is formed on the surface of the VCCD transfer electrode 4 as shown in Fig. 1 and thereon the shielding film 10 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a solid-state imaging device and a method of manufacturing the same.

(Prior Art) In recent years, video cameras using solid-state imaging devices have been actively commercialized.

Hereinafter, a conventional solid-state imaging device will be described with reference to FIG.

Figure 3 shows the interline transfer method COD (hereinafter referred to as I
1 shows a conventional cross-sectional structure of a unit pixel section of a solid-state imaging device called a T-CCD (abbreviated as T-CCD).

1 is an n-type substrate, 2 is a p-well, 3 is a photoelectric conversion section, 4 is a transfer electrode of vertical transfer COD (hereinafter abbreviated as VCCD), 5 is a transfer channel of VCCD, 6 is an insulating film, 7 is an AJ
This is a light-shielding film made by et al.

In the IT-CCD, the photoelectric conversion unit 3 is irradiated with light, the signal charges accumulated over a certain period of time are read out to the transfer channel 5 of the VCCD, and the signal charges are transferred in a direction perpendicular to the plane of the paper.

(Problem to be Solved by the Invention) However, in the conventional structure, the charge 9 caused by the obliquely incident light 8
is mixed into the VCCD channel, which causes a so-called smear phenomenon and significantly deteriorates the quality of the captured image.

If an attempt was made to significantly reduce the smear phenomenon by enlarging the area of the light shielding film 7 to cover the photoelectric conversion section 3 in order to reduce this phenomenon, there was a problem in that the sensitivity decreased.

SUMMARY OF THE INVENTION In view of the above drawbacks, it is an object of the present invention to provide a solid-state imaging device and a method for manufacturing the same, which can significantly reduce the smear phenomenon and improve image quality.

(Means for Solving the Problems) In order to solve the above problems, a solid-state imaging device of the present invention includes:
A light shielding film is formed on the side surface of the charge transfer means.

(Function) By significantly attenuating obliquely incident light or reflected light to the VCCD channel with the above configuration, the smear phenomenon can be significantly reduced.

(Example) Examples of the present invention will be described below with reference to FIGS. 1 and 2 (a).
) to Cc).

FIG. 1 shows an embodiment of the invention.

In FIG. 1, the same reference numerals as in FIG. 3 indicate the same parts, and the explanation thereof will be omitted.

The difference is that a light-shielding film 10 having light-reflecting or light-absorbing properties is formed on the side surface of the VCCD transfer electrode 4. Since the obliquely incident light 11 is reflected or absorbed by the light shielding film 10, it does not go toward the VC:CD transfer channel 5. In this case, the light-shielding film 10 does not need to completely reflect or absorb light. For example, if the transmittance is 10%, the smear caused by such obliquely incident light will be reduced to 10%. As a result, the smear phenomenon is significantly reduced and becomes virtually no problem.

Further, if the light shielding film 10 is an insulating film, it may be formed directly on the side surface of the VCCD transfer electrode 4, or if it is a conductive film, it may be formed on the surface of the VCCD transfer electrode 4 as shown in FIG. An insulating film 6 such as a thermal oxide film may be formed, and a light shielding film 10 may be formed thereon.

Next, an embodiment of the method for manufacturing a solid-state imaging device according to the present invention will be described using FIGS. 2(a) to 2(c).

The same reference numerals in FIGS. 2(a) to 2(c) as in FIG. 1 indicate the same parts, and the explanation thereof will be omitted.

Here, the VCCD transfer electrode 4 is formed of polycrystalline silicon. At this stage, the entire structure is thermally oxidized to form an oxide film 12 as shown in FIG. 2(b). A light-reflecting, light-absorbing, or transmitting light-shielding film 10a is formed over the entire oxide film 12. If a silicon-intermetallic compound (so-called silicide) is used as these light-shielding films 10a, the intensity of obliquely incident light can be significantly reduced.

Alternatively, a double layer of an outer crystalline silicon film and silicide may be used.

Next, anisotropic etching is applied to the state shown in FIG. 2(b). By this anisotropic etching, only the side wall portion of the light shielding film 10a remains as shown in FIG. 2(c), and only the necessary light shielding film 10 is formed.

According to this method, without using a photomask,
The light shielding film 10 can be formed only on the side surface of the VCCD transfer electrode 4, and smear can be significantly reduced with an extremely simple process.

After forming the insulating film 6 and forming the Al1 film from the state shown in FIG. 2(c), a light shielding film 7 is formed using a photomask to realize the structure of the solid-state imaging device shown in FIG. 1.

(Effects of the Invention) As described above, according to the present invention, by forming a light reflective or light absorbing film on the side surface of the charge transfer means, it is possible to significantly reduce smear and improve image quality. can. Furthermore, the method for forming the light shielding film 10 can be achieved in a simple manner by using anisotropic etching without using a photomask, which has great practical effects.

Although the present invention has been explained using an IT-CCD as an example, it is also possible to use a solid-state image carrier (for example, Charge St++eepDQv
It goes without saying that the present invention is also effective for the ICE MO3 type image sensor (FIT-CCD, etc.).

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a solid-state imaging device according to the present invention, FIG. 2 (a) to c) is an explanatory diagram of a method for manufacturing a solid-state imaging device according to the present invention, and FIG. 3 is an explanatory diagram of a conventional solid-state imaging device. An explanatory diagram is shown. 1... N-type substrate, 2... P-well, 3.
...Photoelectric conversion unit, 4...Vertical transfer CCD transfer electrode, 5...Vertical transfer COD channel, 6...
・Insulating film, 7, 10.10a... light shielding film, 8,
11... Incident light, 9... Charge, 12... Oxide film. Patent applicant: Matsushita Electronics Co., Ltd. Agent: Hisashi Hoshino ・J+-
, (,,,/

Claims (3)

[Claims] (1) A solid-state imaging device comprising a plurality of photoelectric conversion elements, and a light shielding film is formed on a side surface of a charge transfer means adjacent to the photoelectric conversion elements. (2) The solid-state imaging device according to claim (1), wherein the light shielding film is a semiconductor-intermetallic compound. (3) In a solid-state imaging device equipped with a plurality of photoelectric conversion elements and a charge transfer means adjacent to the photoelectric conversion elements, after forming part or all of the charge transfer means formed above the photoelectric conversion elements, A method for manufacturing a solid-state imaging device, comprising forming an oxide film, forming a light shielding film, and then performing anisotropic etching to form a film that prevents unwanted light from entering a transfer channel of a VCCD. .