JPS63272074A - Color solid-state image pickup device and its manufacture - Google Patents

Abstract

PURPOSE:To obtain the device which is stable and good in its vertical resolution and applicable to an electronic still camera, by using magenta filters of half concentration, yellow filters and cyan filters of normal concentration to compose a bilayer structure color filter and by suchlike. CONSTITUTION:A color solid-state image pickup device of a color line serial system is composed of the following parts: a sensitive part where photoelectric conversion parts serving as picture elements are disposed in a matrix shape, and color filters which are formed in the respective picture elements by making magenta and cyan, cyan and green, green and yellow, yellow and magenta, combined respectively on halves in their areas. Said color filters in such a device are composed of band-shaped second cyan filters 13, which are formed above a row where yellow filters 5 and magenta filters 9 of half concentration are formed alternately, and band-shaped second yellow filters 11 which are formed above a row where cyan filters 7 and magenta filters 9 of half concentra tion are formed alternately.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a color solid-state imaging device and a method for manufacturing the same, and is particularly used in an electronic still camera.

(Prior Art) A color solid-state imaging device extracts color signals by forming color filters corresponding to photoelectric conversion sections formed in a matrix.

Various conventional color imaging methods have been proposed, such as a three-panel system that separates the three primary colors of red, green, and blue, but many of them do not have good sensitivity, and a new color-difference line sequential method has been proposed to solve this problem. There is. This is Kono et al.: Complete color difference line sequential single plate color one-sided system, Television Society Technical Report E
D836 (February 1985) and Makoto Fujimoto: Camera method, Journal of the Television Society, Vol. 40. No. 11° p. 1073 (1986), etc., and is a method in which color signals are obtained alternately line-sequentially in the form of color difference signals.

FIG. 7 is a plan view showing a color filter array used in this method, with the left side showing the field storage method and the right side showing the frame storage method. First, in the case of the field storage method, the first column is magenta (Mg), cyan (Cy), magenta, green (
G), and the second column is green, yellow (Y
), magenta, and yellow, and these two columns are repeated, and in the first field that provides a certain scanning line, by reading the first and second rows together, Mg+cy, and cy+c by reading out the second and third rows together in the second field that provides the next scan line.

and Y+Mg.

In addition, in the case of the frame storage method, each color filter is a combination of two filters that are half the size of those in the field storage method, and the first row is Mg/Cy,
G/Y is repeated, and in the second row, Cy/G and Y/Mg are repeated. By reading out such a filter one row at a time for each frame, M g + Cy
, and G+Y signals, and in the second frame C)/+
G, and Y+Mg signals are obtained.

The field storage two-shuttle mixed readout method is the mainstream in current video cameras, but the resolution is affected by the pixel size and sufficient vertical resolution cannot be obtained, and high resolution is required like in electronic still cameras. It is not suitable for those who

For this reason, electronic still cameras use a frame accumulation one-line readout method, but in this case, the resolution of the color filter material, such as casein, is not good, so the accuracy of the seam of different color filters is It is difficult to form each color by 1/2 completely, and one of the colors appears particularly strong, causing flicker noise to appear on the color difference signal, making it difficult to obtain a satisfactory result. It is.

(Problems to be Solved by the Invention) As described above, it is difficult to obtain a conventional color solid-state imaging device that has good vertical resolution and is free from noise.

The present invention has been made to solve such problems, and an object of the present invention is to provide a color solid-state imaging device that can obtain stable and good vertical resolution.

[Structure of the invention]

(Means for Solving the Problems) According to the present invention, there is provided a photosensitive section in which photoelectric conversion sections forming pixels are arranged in a matrix, magenta and cyan, cyan and green, each having an area of 172 in each pixel. In a color solid-state imaging device using a color difference line sequential method having color filters consisting of a combination of green, yellow, yellow and magenta, the upper layer of a row in which yellow filters and magenta filters having a density of 1/2 are formed alternately. and a second belt-shaped yellow filter formed on the upper layer of the row in which cyan filters and magenta filters with a density of 1/2 are alternately formed. It is characterized by

Further, according to the method of manufacturing a color solid-state imaging device according to the present invention, there is a step of forming a transparent flattening layer on the substrate on which the photosensitive pixel portion and the light shielding layer are formed, and a step of forming a yellow layer on the flattening layer. 1.3fi2 consisting of cyan and magenta,
forming a third dyed layer in a predetermined pattern with the first and second intermediate layers interposed therebetween, and forming a third intermediate layer and a fourth dyed layer of yellow or cyan in a predetermined strip pattern; The fourth intermediate layer and the fifth dyed layer of cyan or yellow are formed in a predetermined strip pattern, and the magenta dyed layer is dyed to 1/2 the density.

(Function) Figures 8, 9, and 10 are yellow (Y), respectively.
It shows the spectral transmittance characteristics of cyan (Cy) and magenta (Mg). These are blue (B) and red (R), respectively.
), green CG), the ideal spectral characteristics are as shown in FIG. FIG. 5 shows the filter structures of Cy+Mg, Y+Mg, and Y+GSCy+G obtained with the structure of FIG. 1, and FIG. 6 shows the corresponding spectral characteristics. Note that green is obtained by superimposing cyan and yellow.

For example, in the case of Cy+Mg, cyan overlaps 1/
In the area of 2, the red side transmitted by magenta is cut off by cyan, resulting in a solid line, so it can be seen that the density of magenta should be set to 172. This is Y
The same applies to the case of e + M g.

In this way, by reducing the magenta dyeing density to 1/2 and employing a two-layer structure, it becomes possible to stably obtain desired spectral characteristics.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a plan view showing an embodiment of a color solid-state imaging device according to the present invention, and FIG. 2 is a cross-sectional view taken along the line A-A, showing the structure of the formed color filter. .

According to these figures, an aluminum light shielding layer 20 having an opening 21 corresponding to the photoelectric conversion section is formed on a substrate in which a photoelectric conversion section (not shown) is formed. A yellow layer 5, a cyan JW layer 7, and a magenta layer 9 are formed in a predetermined pattern thereon. That is, the filter layers are arranged so that the magenta layer 9 and the yellow layer 5 appear alternately in the first and fourth rows, and the magenta layer 9 and the yellow layer 5 alternately appear in the second and third rows. There is. In the first and fourth rows, the second cyan layer 13 is formed in a band shape passing approximately through the center of the opening 21, and in the second and third rows, the second yellow layer 11 is formed in the opening 21. It is formed into a band shape that passes through the center. The width of the second yellow single layer 11 and the second cyan layer 13 formed in a band shape in this way is the width of the opening 21.
It is half the width of

In a color filter with such a configuration, the upper layer filter formed in a band shape has a width of 172 times the width of the lower layer filter, and is formed within the area of the lower layer filter, so even if a slight pattern shift occurs, the two Since the area ratio of the filter is constant, there is almost no change in the spectral characteristics, and stable spectral characteristics can be obtained.

Then, color difference signals of Mg+Cy-(G+Ye) and Mg+Ye-(G+Cy) are obtained for each horizontal pixel scan, and
A stable luminance signal of Mg+Cy+G+Ye is always obtained.

In addition, in the example, the lower layer magenta, cyan, and yellow filters are vertically continuous for each two pixels from the viewpoint of ease of manufacturing.Magenta and cyan, and magenta and yellow are All different color filters may be formed in adjacent pixels as long as they are arranged repeatedly.

FIG. 3 is a cross-sectional view of the element by step, showing the manufacturing method according to the present invention for realizing such a structure.

First, an acrylic resin-based transparent layer 2 called a base layer is formed on a substrate 1 on which a photoelectric conversion section, a light shielding section (none of which are shown), and polysilicon wiring layers 3 and 4 have already been formed.
is formed on the entire surface (Fig. 3(a)). This base layer 2 absorbs irregularities caused by the wafer process and improves the density with the subsequent dyeing resist.

Next, a dyeable resist mainly composed of casein or the like is formed on the entire surface, patterned so that only predetermined areas remain, and dyed yellow to obtain yellow layer 5 (third layer).
Figure (b)).

Subsequently, a transparent intermediate layer 6 is formed on the entire surface, and a second dyeable resist is applied thereon, patterned, and dyed cyan to obtain a cyan layer 7 (FIG. 3(C)).

Next, a transparent intermediate layer 8 is similarly formed on the entire surface, and a third dyeable resist is applied thereto, buttered, and dyed magenta to obtain a magenta layer 9 (see Fig. 3). d
)). This magenta dyeing has a density that is half the density required for r-domain.

To obtain such a half concentration, either the immersion time in the dyeing solution is halved or the dye concentration of the dyeing solution is halved.

Thereafter, by the same process, the intermediate layer 10 and the second yellow layer 1 are formed.
1. Form the intermediate layer 12 and the second cyan layer 13 in sequence, and finally protect: JII! The overcoat layer 14 as I is formed to complete the color filter formation process.

Note that the order in which the filter layers of each color are formed is not limited to that shown in the embodiment. Moreover, the patterning of each color filter may be performed after dyeing, or the dyeing may be performed after patterning.

〔Effect of the invention〕

As described above, according to the color solid-state imaging device according to the present invention, a band-shaped cyan filter is placed in the upper layer of the row in which magenta filters having a density of 1/2 and yellow filters having a normal density are arranged alternately. Since a band-shaped yellow filter is formed above each row in which magenta filters having a density of /2 and cyan filters having a normal density are arranged alternately, it is possible to read out one line of frame accumulation. Since the color difference signal and the luminance signal are stably obtained, vertical resolution twice as high as that of the conventional method can be obtained. Therefore, it is suitable for electronic still cameras.

Furthermore, since the upper layer color filters are formed in a band shape within the lower layer region, even if vertical and horizontal shifts occur between the color filters, there is no change in the spectral characteristics, and a stable image can be obtained.

Further, according to the method for manufacturing a color solid-state imaging device according to the present invention, since all the color filter layers are formed as different layers, manufacturing can be performed extremely stably.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a color filter structure of a color solid-state imaging device according to the present invention, FIG. 2 is a sectional view taken along line A-A, and FIG.
The figure is a cross-sectional view of the element by process showing how to obtain the color filter structure shown in Fig. 1, Fig. 4 is a characteristic diagram showing the required spectral characteristics of each dyeing layer, and Fig. 5 shows a part of the structure of Fig. 1. A cross-sectional view, Fig. 6 is a characteristic diagram showing the spectral characteristics obtained with the structure of Fig. 5, and Fig. 7 is a characteristic diagram showing the spectral characteristics obtained with the structure of Fig. 5.
This figure is a plan view showing a conventional filter structure, and FIGS. 8, 9, and 10 are characteristic diagrams showing actual spectral transmission characteristics of yellow, cyan, and magenta, respectively. DESCRIPTION OF SYMBOLS 1...Substrate, 2...Base layer, 5...Yellow layer, 6°8.10.12...Intermediate layer, 7...Cyan layer, 9...Magenta layer, 11...・Second yellow layer, 1
3... m2 cyan layer, 14... overcoat layer. Applicant's agent Sato-Yu IA Figure 1 20 Figure 2 3 Sono Mg Cy Ye (α)
(1)) (C) Figure 4 Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] 1. A photosensitive section in which photoelectric conversion sections forming pixels are arranged in a matrix, magenta and cyan having an area of 1/2 in each pixel,
In a color solid-state imaging device using a color difference line sequential method, which includes a color filter consisting of a combination of cyan and green, green and yellow, and yellow and magenta, the color filter includes a magenta filter having a density 1/2 that of the yellow filter. A band-shaped second cyan filter formed on the upper layer of the rows formed alternately; and a band-shaped second yellow filter formed on the upper layer of the row in which the cyan filter and the 1/2 density magenta filter were formed alternately. A color solid-state imaging device characterized by comprising a filter. 2. The color solid-state imaging device according to claim 1, wherein the upper layer band-shaped filter has a width that is half the opening width of the lower layer filter. 3. Forming a transparent flattening layer on the substrate on which the photosensitive pixel portion and the light shielding layer are formed, and applying a first dyed layer of yellow, cyan, or magenta on the flattening layer in a predetermined pattern. a step of forming a first intermediate layer and a second dyed layer of yellow, cyan, or magenta in a predetermined pattern; a step of forming a first intermediate layer and a second dyed layer of yellow, cyan, or magenta; a step of forming a third intermediate layer and a fourth dyed layer of yellow or cyan in a predetermined strip pattern; a step of forming a third intermediate layer and a fourth dyed layer of cyan or yellow in a predetermined strip pattern; forming a fifth dyed layer in a predetermined band-like pattern, and the magenta dyed layer is dyed to 1/2 density. 4. The method of manufacturing a color solid-state imaging device according to claim 3, wherein staining with a density of 4.1/2 is obtained by half the immersion time in the staining solution. 4. The method of manufacturing a color solid-state imaging device according to claim 3, wherein dyeing with a 5.1/2 density is obtained by immersion using a dye solution with a half density.