JPS58171A - Solid state image pickup device - Google Patents

Abstract

PURPOSE:To prevent fogging and thereby to improve resolution by a method wherein a structure is employed, wherein light incident upon a certain picture element does not exemplifiedly due to reflection reach neighboring picture elements, in a solid state image pickup device wherein a light shield is provided vertical to the device substrate in places not occupied by light receiving sections constituting the photosensitive regions for the device. CONSTITUTION:A multiplicity of picture elements consisting of an N<+> light receiving section 2, an N<+> type transfer section 3, an N<+> type overflow drain section 4 is formed on an Si substrate. Above each transfer section 3, piled one upon another buried in the SiO2 film 5 are polycrystalline charge transfer electrodes 6, 7, and an Al film 8 serving as a transfer-to-the-drain-section electrode and light shield. They are then covered with a passivation film 9 composed exemplifiedly of PSG, when an opening is provided above the film 8 and is filled with photosensitive substance, and the opening is converted into a light shield section 16 balck in color after prescribed treatment. A glass substrate 12 with a color separating filter 11, a light shield film 13, a colored filter 14 underneath is attached by means of adhesive 10, for incidence of a light 15 upon the receiving section 2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a solid-state MS device, and in particular provides a solid-state MS device with a high resolution device and good color separation with fewer colors.

Conventionally, in order to obtain a color solid-state image sensor, a method has been used in which a predetermined color separation filter is bonded onto a solid-state image sensor such as a COD using a κ adhesive.

Figure 1 is an example. A light receiving section (2), a transfer section (3) and an Ohno {-
7. Form the drain part (4), etc. The upper part κ is
Polycrystalline silicon electrodes 11 (6), (F) are formed on the oxide film (5) to serve as charge transfer electrodes. Form an electrode made of AJ film (8) that also serves as a shield.Although the example shown in Figure 1 is a two-layer polycrystalline silicon electrode, a three-layer polycrystalline silicon electrode is used, and the AJ film (8) of the light shield is
A film may be formed. Insulation between the electrodes is provided by an oxide film. Further, on the upper part, a base plate II (9) usually made of PEG (phosphosilicate glass), 88G (boric acid glass), 81sN4, etc. is formed to protect the element.

When used as a color image sensor, adhesive Cll
A color separation filter αυ is bonded through the filter. The color separation filter I is formed on a glass substrate α, and has a red color and a light shielding film A3 made of chromium oxide or the like.

Green, nine, blue, etc. are made up of O color filters a4.

The light receiving section (2) and the 10 color filters are pasted together in a correct positional relationship.

Most of the incident light α9 from the subject passes through the color filter and reaches the light receiving surface #II4, but a portion of the incident light hits the At film (8) depending on the relative positional relationship with the fill voice.

Depending on the degree of lens shading of the camera, the more the iris is opened, the more the incident light rays become oblique, and the more the rays of light fall on λL18). The U membrane (8) prevents these light rays from entering areas other than the baby's area.
In other words, 1, for example, light enters the vicinity of the transfer section (3), 8
Carriers are generated by photoexcitation in the four substrates, and these carriers are prevented from deteriorating image quality by mixing with signal charges being transferred and from entering directly into the light-receiving section of **, causing color mixture. This operation to ensure better quality is not only performed by the At film (8), but also by the black original shield IIaI made of chromium or chromium oxide of the color separation filter.

Similar to the color G1 element described above, a light shield film is provided (although this has the disadvantage that light leaks to adjacent pixels, causing color mixing).

In other words, as shown in Fig. 111, the light that hits the M film of the shield is reflected and propagates through the Budgebage carbon film, causing color mixture. have.

The present invention has been developed in view of the above points, and includes a leading conductor substrate on which a photoelectric conversion region and a charge transfer region are formed, a charge transfer electrode formed on the charge transfer region via a first insulating layer, and a charge transfer electrode formed on the charge transfer region via a first insulating layer. A light shield portion is formed on the charge transfer electrode via a second insulating layer and absorbs IIN or a light shield portion that propagates in a direction parallel to the above-mentioned conductor substrate (therefore,
The object of the present invention is to provide a solid-state image sensor that prevents color mixture and is highly resolvable.

Hereinafter, the present invention will be described in detail based on embodiments with reference to the drawings. FIG. 2 is a schematic cross-sectional view of the ninth sigma illustrating the present invention. Note that the same parts as in FIG. 81 will be described with the same reference numerals. As shown in Fig. 1112, the structure of the solid-state sensor I# is the same as that of the tm, but a part of the badge page II (9) above %MII (83) is etched. In the case of a film, apply a resist on the # film, perform the prescribed exposure, leave the resist film in areas other than the areas to be etched, and perform wet etching with a NH4F or NH4F-based etching solution to remove as much D as possible. Aj
Perform etching to the area close to the film. After this, apply a photosensitive agent used for black and white 4-tone film, etc., onto the film and thoroughly fill the etched area. Shine light and expose it to light 1
image and fixing to form a black light shield portion Ill. In this case, at the time of etching, leave the resist film and apply the photosensitizer directly to the entire surface, then apply KjJ to the entire surface.
A black light shielding film may be left only in the etched area by removing the resist Alt1 without fixing the image or image layer.

When the At film is formed in the exposed film in this way, as shown in Figure 2, the light reflected by the At film is blocked by the black original shield part in the element and passes into the adjacent Lii element. It is possible to prevent color mixing without reaching the surface.

Optically, it is desirable that the M film (8) and the black shield part Q (9) be connected, but the reaction between the λ film and the silver particles of the photographic film O may lead to concerns about longevity and reliability. Therefore, if the gap is not large, it is best to open it appropriately, the reflected light from the At film will always be at the bottom of the black shield part O.
This is because it is absorbed and produces the same effect. %) As a measure to prevent the above reaction, a passive 7W film made of 813N4 polyimide, which is more p-dense than the PEG film, may be used, or such a film may be formed thinly over the entire surface after the above etching.

Next, a second embodiment of the present invention will be described with reference to FIG. The same parts as in FIG. 1 will be described with the same reference numerals. As in FIG. 2, this is an example in which a part of the padding waste film is etched, and the etched part is used for an eK color separation filter or a light shield layer ση of chromium oxide is formed. In the case of a chromium film, it does not absorb light, but it can prevent light from leaking to neighboring pixels by reflecting it.However, if it is used in combination with a chromium oxide film, the reflection will be weakened, so it should be used on the single-source incident side. It is better to use a chromium chloride film for this purpose.

In addition to the embodiments 01iIl and 4 described above, as shown in FIG. 3, there is no need for a black light shielding film in the color separation filter αη. Light shielding is done in the shield part of the PADGE PAGE carbon film, which is close to the light receiving part of the pixel, so if you try to do the light shielding only on the 0 color separation filter side, which can fulfill its role with a small area, it will be difficult to use adhesive. It is necessary to take into account the thickness of the agent and design it so that the incident light does not enter the four Ifl elements, which inevitably increases the area of the shield part, which is a drawback that even the effective aperture area is lost. There is.

According to the present invention, as shown in FIG. 3, the color separation filter can be formed of red, green, or real color filter parts, and the incident light can be effectively guided to the light receiving section. Furthermore, in the conventional method, care is taken when laminating the light-receiving portion of the pixel and the color separation filter to maintain a very strict positional relationship, but the present invention has the advantage that a slight misalignment is allowed.

Furthermore, it goes without saying that the light shield layer αη in FIG. 3 may be an A7 film. A/When using a metal film such as a membrane,
Since it can serve as both an electrode and a light shield, λ!
The film (8) and the light shield l1llaη may be connected to each other or may be formed as an integral structure. It is sufficient to have a base shield film that serves as a direct component; however, from the viewpoint of reliability, it is desirable to apply a thin badge page film on the top surface of the metal film.

In the above embodiment, the color separation filter is pasted or bonded, but the present invention can also be applied to the case where the color separation filter is directly formed on a solid-state image sensor as shown in FIG.

Normally, when forming color separation filters directly, the coating film is smoothed (as explained in Figure 2 and p. 11). All you have to do is form the edge of the light shield part, and then form a color separation filter on top of it.5 Note that in the case of Figure 4, the particles from the human genus are reflected at the boundary with the color separation filter. , this is extended vertically in the middle by a light traveling shield part.
It is something.

Although the above embodiments are explained within a chip where pixels of a solid-state image sensing device are located, there are four cases in which light traveling from a person at the edge of the chip enters the inside of the chip and causes shading or the like. Even in such a case, it can be completely prevented by etching the pad page attack film around the chip and providing a vertical light shield portion as in the present invention.

In addition, in the example, explanation will be made using the photosensitizer of black and white photographic film, but this is not limited to this, and black using a similar method can also be used for color film. Of course, it is also possible to use a black color formed by Particularly in the latter case, there is a concern that the black level is not sufficient, but if we consider light absorption in terms of horizontal thickness,
Since it is from 3 μm to several μm, it is sufficiently useful.

Furthermore, as a solid-state image sensor, interline transfer @CC
I mentioned the example of D, but frame transfer type C'CD and MO8-
? Of course, it can also be used for BBD 6 or CID.

As described above, by forming a light shielding film in a direction perpendicular to the element substrate on parts other than the light receiving part forming the photosensitive part of a solid-state image sensor, light incident on a predetermined pixel is reflected, etc.
Since it is the purpose of the present invention to have a configuration in which the length is 11 m, in this case, the direction perpendicular to the element substrate is literally 6 m.
-Even if it is not an electric beam, if there is an effective l direct component O shield part in an oblique state, the path of light in the horizontal direction can be blocked, so the purpose can be achieved.

In addition, in the example, it was explained that the light shield part is provided in the etched part of the badge page seal film, but in the case of the light shield layer made of a metal film, which is the advanced form shown in FIG. (It may also be configured to cover the entire surface of the infestation to stop its original propagation in the horizontal direction; in this case, etching to provide a shield layer is not necessary.

In the embodiment, an example of a color solid-state image sensor is shown, but even in a solid-state image sensor that does not use a color separation 1wI filter, the element of the present invention can have a high degree of resolution without fogging due to light leakage. it is obvious.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing a conventional solid-state image sensor, and FIGS. 2 to 4 are schematic cross-sectional views of the solid-state image sensor in an embodiment of the present invention. In fig. 1... Silicon substrate, 2... Light receiving section, 3... Transfer section. 4... Overflow drain, 5... Oxide film,
6.7... Polycrystalline silicon electrode, 8... AI film, 9
...Badge page desecration, 10...Adhesive, 11
...color filter, 12...incident light, 16.17.
...Light shield part.

Claims (1)

[Scope of Claims] A semiconductor substrate in which a charge conversion region and a charge transfer region are formed, a charge transfer electrode formed on the charge transfer region with a first insulating layer interposed therebetween, and a charge transfer electrode formed on the charge transfer electrode. What is claimed is: 1. A solid-state imaging device comprising: a light shield portion formed through a second insulating layer, which blocks, absorbs and blocks light propagating in a direction parallel to the semiconductor substrate. 2) The solid-state image pickup device according to item 11 of the patent, characterized in that the charge transfer electrode and the light shield portion are formed as one.