JPH0263201B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a color solid-state image sensing device using a semiconductor substrate, and particularly to the configuration of a color filter that improves the color characteristics of color imaging.

[Prior art]

In general, color solid-state image sensors using this type of semiconductor substrate have many advantages over conventionally well-known color image pickup tubes, but improvements in light sensitivity and color characteristics still need to be improved. , the removal of on-screen noise called blooming or smearing. Various considerations have been made into the causes of this noise on the screen, and countermeasures have been taken, but fundamentally it is important to take measures to reduce the generation of charges due to incident light.

The charges generated on the semiconductor substrate by this incident light can be divided into those in the area of the photodetector and those in other areas, but the charges in the former area are necessary because they are the purpose of the device. However, the charge in the latter region is completely unnecessary, and the light incident on this latter region must be blocked. The configuration of a conventional color solid-state image sensor that takes measures to block light to this latter region is shown in the first example.
As shown in the figure. That is, in FIG. 1, on the silicon semiconductor substrate 1, the p-n
A bonding surface is formed to form a photosensitive element portion, and charges generated in this photosensitive element portion are transferred to a drain 4 by a gate 3 and outputted to the outside from a vertical signal line 5. Here, since the incident light generates charges in areas other than the photosensitive element, in order to suppress this, the area other than the photosensitive element is shielded from light by the metal film 6, but in order to form this metal film 6, This requires an insulating film 7, which causes the structure in the vicinity of the metal film 6 to bulge, and for this reason, it is necessary to deposit a planarizing film 8 on the area of the photosensitive element, and then apply it over these layers. Color filters 9 and 10 are formed on.

Therefore, in the case of this conventional configuration, a large step is created between the region of the photosensitive element portion formed by the diffusion layer 2 and the other regions of the gate 3, drain 4, and vertical signal line 5, and this large step is caused by the incident light. A part of the incident light enters the substrate 1 as a maze of light and causes noise. In other words, this conventional configuration cannot prevent stray light from entering the board, and as a result, charges generated within the board act on the vertical signal lines, causing a phenomenon in which highlights spread on the screen, ie, blooming or smearing. This had the disadvantage of causing problems.

[Summary of the invention]

In view of these conventional drawbacks, the present invention proposes a means for blocking the optical path that enters the silicon semiconductor substrate as stray light in order to suppress noise generated on images, that is, blooming and smear phenomena. be.

In the case of a color solid-state image sensor, it takes about 20
Tens of thousands of picture elements are formed, and it is necessary to inspect whether all of these imaging functions are working correctly, and one of these inspections is observation using a microscope. That is, it is an important condition that parts other than the light receiving element can be optically observed. It is also known that the depth of light penetrating into a semiconductor depends on its wavelength, with blue being shallower and penetrating deeper from green to red. According to the applied electric field, adjacent picture elements are electrically influenced.

Therefore, in this invention, taking these conditions into consideration,
When a yellow mosaic pattern is used as a color filter, the yellow mosaic pattern is characterized in that it also covers the area that causes stray light, thereby blocking the optical path of the stray light.

[Embodiments of the invention]

Hereinafter, one embodiment of the color solid-state image sensing device according to the present invention will be described in detail with reference to FIGS. 2 to 4.

FIG. 2 shows a mosaic pattern including a yellow filter according to this embodiment, and consists of three color patterns: a green (G) pattern 11, a cyan (Gy) pattern 12, and a yellow (Ye) pattern 13.

Furthermore, FIGS. 3 and 4 are cross-sections taken along lines -,, in FIG. 2, and in each figure, the same reference numerals as in FIG.
All parts other than the diffusion layer 2 corresponding to each color are covered with a yellow (Ye) pattern 13, and in particular in this case, the parts corresponding to the green (G) pattern 11 and the cyan (Cy) pattern 12 are covered. It is sufficient to simultaneously form a yellow (Ye) pattern 13 that also serves as a light shielding film except for the portions other than the diffusion layer.
Thereafter, after forming the flattening film 8, a green (G) pattern 11 and a cyan (Cy) pattern 12 may be formed.

In the case of this embodiment, the yellow (Ye) pattern 13, which also serves as a light-shielding film, is formed in conjunction with the surface unevenness, so there is almost no stray light entering, and the shallow region above the pattern 13 is colored green and cyan. Blooming and smearing phenomena can be greatly reduced by only generating electric charges due to
As a result, the entire manufacturing process can be greatly simplified.

In the above embodiment, the light shielding film is formed at the same time as the yellow (Ye) pattern, but it goes without saying that they may be formed separately. In addition, it may be used in combination with a conventional metal light-shielding film.
It is also applicable to CID type etc.

〔Effect of the invention〕

As detailed above, according to the present invention, in a color solid-state image sensing device in which a mosaic pattern including a yellow pattern is formed on a semiconductor substrate, the entire imaging surface except for the photosensitive portion corresponding to patterns other than the yellow pattern, Since the yellow pattern is formed as a light-shielding film at the same time as the yellow pattern formation or separately, it is possible to prevent stray light from entering the substrate, suppress blooming and smear phenomena, and simplify the device manufacturing process. It has features such as being useful for improving the reliability of the element itself.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the main structure of a conventional color solid-state image sensor, FIG. 2 is a plane mosaic pattern diagram of a color solid-state image sensor to which an embodiment of the present invention is applied, and FIGS. 3 and 4. Figure 2-
It is a sectional view of a line part and a - line part. DESCRIPTION OF SYMBOLS 1... Silicon semiconductor substrate, 2... Diffusion layer (photosensitive part), 3... Gate, 4... Drain, 5...
... Vertical signal line, 7 ... Insulating film, 8 ... Flattening film,
11...Green pattern, 12...Cyan pattern, 13...Yellow pattern that also serves as a light shielding film.

Claims (1)

[Claims] 1. In a color solid-state image sensor in which a mosaic pattern including a yellow pattern is formed on a semiconductor substrate, a light-shielding film is applied to the entire imaging surface excluding the photosensitive portion corresponding to patterns other than the yellow pattern, either simultaneously with the formation of the yellow pattern or separately. A color solid-state image sensor characterized by forming a yellow pattern.