JP2519720B2 - Color solid-state imaging device and manufacturing method thereof - Google Patents

Description

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

(Prior Art) A color solid-state image pickup device forms a color filter corresponding to a photoelectric conversion unit formed in a matrix and extracts a color signal.

Various color imaging systems have been proposed, such as a three-plate system for dividing into three primary colors of red, green, and blue.
Many have poor sensitivity, and a new method for solving this is the color difference line sequential method. This is Kono et al .: Complete color difference line-sequential single plate color system, Technical Report of the Television Society
ED836 (February 1985) and Makoto Fujimoto; camera system, those introduced in the Television Society of Japan, Vo1.40, No.11, p1073 (1986), etc., where color signals are in the form of color difference signals. This is a system in which it is obtained alternately in sequence.

FIG. 7 is a plan view showing a color filter array used in this system. The left side shows the case of the field storage system and the right side shows the case of the frame storage system. First, in the case of the field storage method, the first column is magenta (Mg), cyan (Cy), magenta, green (G).
The second row is green, yellow (Y),
The arrangement is such that magenta and yellow are arranged in this order, and then these two columns are repeated. By reading the first row and the second row together in the first field that gives a certain scanning line,
The signals of Mg + Cy and G + Y are obtained, and Cy + G and Y + Mg are obtained by reading out the second and third rows together in the second field which gives the next scanning line.

Also, in the case of the frame storage method, each color filter is a combination of two filters of half the size of those in the field storage method. The first line is Mg / Cy, G / Y.
Is repeated, and Cy / G and Y / Mg are repeated in the second line. By reading such a filter row by row for each frame, signals of Mg + Cy and G + Y are obtained in the first frame, and signals of Cy + G and Y + Mg are obtained in the second frame.

The field-storage two-row mixed readout method is the mainstream of the current video cameras, but the resolution depends on the pixel size, and a sufficient vertical resolution cannot be obtained, so that a high resolution is required like an electronic still camera. Not suitable for things.

For this reason, the frame accumulation one-row reading method is used for the electronic still camera, but in this case, since the resolution of the color filter material, such as casein, is not good, the accuracy of the seam portion of different color filters is reduced. Badly each color completely
It is difficult to form 1/2 of each color, one of the colors is particularly strong, and flicker (flickering) noise appears on the color difference signal, and it is difficult to obtain a satisfactory one.

(Problems to be Solved by the Invention) As described above, in the conventional color solid-state imaging device, it is difficult to obtain a device having good vertical resolution and no noise.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a color solid-state imaging device capable of obtaining stable and favorable vertical resolution.

[Structure of Invention]

According to the color solid-state image pickup device of the present invention, a photosensitive unit in which photoelectric conversion units forming pixels are arranged in a matrix, and magenta and cyan having an area of 1/2 in each pixel,
In a color-difference line-sequential color solid-state imaging device including a color filter formed of a combination of cyan and green, green and yellow, yellow, and magenta, the color filter includes a yellow filter that completely covers the opening of the pixel. A magenta filter having a density of 1/2 which completely covers the opening of the pixel is formed alternately in the row direction,
1 / of the opening width of the pixel
A first row having a width of 2 and consisting of a combination of strip-shaped cyan filters running in the row direction so as to fit within the opening of the pixel; a cyan filter completely covering the opening of the pixel and the opening of the pixel. A magenta filter having a density of 1/2 that completely covers the area, is overlapped with the rows formed alternately in the row direction, and has a width of 1/2 of the opening width of the pixel. , A second row composed of a combination of band-shaped yellow filters running in the row direction so as to be accommodated in the opening of the pixel is alternately arranged.

Further, according to the method for manufacturing a color solid-state imaging device of the present invention, a step of forming a transparent flattening layer on a substrate on which a photosensitive pixel portion and a light shielding layer are formed, and a yellow flattening layer on the flattening layer. The first row in which the filters and the 1/2 density magenta filters are alternately arranged and the second row in which the cyan filters and the 1/2 density magenta filters are alternately arranged are alternately arranged, yellow,
A first dyeing layer of cyan and magenta of 1/2 density is formed in a predetermined pattern that completely covers the opening of the corresponding pixel in each row, and a first intermediate layer and yellow, cyan, and
The second dye layer of magenta of 1/2 density is formed in a predetermined pattern that completely covers the opening of the corresponding pixel in each row, and the second intermediate layer and yellow, cyan, 1/2 density are formed on it. Forming a third dyeing layer of magenta in a predetermined pattern that completely covers the openings of the corresponding pixels in each row, and forming a fourth dyeing layer consisting of a third intermediate layer and yellow in the cyan and A step of forming a predetermined strip-shaped pattern so that the dyed layer of magenta has a width of 1/2 of the opening width of the pixel of the row formed alternately, and completely fits within the opening of the pixel, A fourth intermediate layer and a fifth dyeing layer consisting of cyan,
The yellow and magenta dyed layers have a width half the width of the opening of the pixel in a row in which the dyed layers are alternately formed, and are formed in a predetermined band-shaped pattern so as to completely fit in the opening of the pixel. And a process.

(Working) Figures 8, 9 and 10 show yellow (Y) and
It shows the spectral transmittance characteristics of cyan (Cy) and magenta (Mg). Since these are complementary colors of blue (B), red (R), and green (G), the ideal spectral characteristics are as shown in FIG. FIG. 5 shows the filter structure of Cy + Mg, Y + Mg, Y + Cy, and Cy + Ye obtained with the structure of FIG. 1, and FIG. 6 shows the spectral characteristics corresponding to these.
In addition, green is obtained by superimposing cyan and yellow.

For example, in the case of Cy + Mg, in the area of 1/2 area where cyan overlaps, the red side that transmits with magenta is cut by cyan and becomes like a solid line, so the density of magenta should be halved. I understand. This also applies to the case of Ye + Mg.

In this way, after halving the dyeing density of magenta,
Due to the two-layer structure, the width of the strip filter is 1 / the width of the pixel opening.
Since the band-shaped filter has a width of 2 and completely fits within the opening of this pixel, it is possible to stably obtain desired spectral characteristics without being affected by the positional deviation of the filter-making state. .

Embodiment An embodiment of the present invention will be described in detail below 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 sectional view taken along the line AA, showing the structure of a formed color filter. .

According to these drawings, an aluminum light-shielding layer 20 having an opening 21 corresponding to the photoelectric conversion unit is formed on a substrate in which a photoelectric conversion unit (not shown) is formed. A yellow layer 5, a cyan layer 7, and a magenta layer 9 are formed in a predetermined pattern on the above. That is, the first
The filter layers are arranged so that the magenta layer 9 and the yellow layer 5 appear alternately in the fourth row, and the magenta layer 9 and the yellow layer 5 appear alternately in the second and third rows. Then, in the first and fourth rows, the second cyan layer 13 is formed in a band shape so as to pass 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 in a strip shape so as to pass through almost the center. The width of the second yellow layer 11 and the second cyan layer 13 thus formed in a strip shape is half the width of the opening 21.

In the color filter having such a configuration, the upper layer filter formed in a band shape has a width of 1/2 of that of the lower layer filter and is formed in the region of the lower layer filter, so that even if some pattern shift occurs. The area ratio of the two filters is constant, the spectral characteristics hardly change, and stable spectral characteristics can be obtained.

Then, for each horizontal pixel scan, Mg + Cy− (G + Ye) and Mg +
Color difference signal of Ye- (G + Cy) is obtained, and Mg + Cy + G
A stable luminance signal of + Ye will always be obtained.

In the embodiment, each of the lower magenta, cyan, and yellow filters is vertically continuous by two pixels from the viewpoint of facilitating manufacturing. However, magenta and cyan, and magenta and yellow are arranged in the row direction. Different color filters may be formed in adjacent pixels as long as they are arranged repeatedly.

FIG. 3 is a cross-sectional view of elements for each step showing a 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 the entire surface of the substrate 1 on which the photoelectric conversion section and the light-shielding section (none of which are shown) and the polysilicon wiring layers 3 and 4 are already formed. (FIG. 3 (a)). The base layer 2 absorbs the irregularities generated by the wafer process and improves the adhesion with the subsequent dyeable resist.

Next, a dyeing resist mainly composed of casein or the like is formed on the entire surface, patterned so that only a predetermined region remains, and dyed in yellow to obtain a yellow layer 5 (FIG. 3 (b)).

Then, a transparent intermediate layer 6 is formed on the entire surface, and a second intermediate layer 6 is formed on the transparent intermediate layer 6.
The dyeing resist of No. 3 is applied, this is patterned, and dyed with cyan to obtain a cyan layer 7 (FIG. 3 (c)).

Next, similarly, a transparent intermediate layer 8 is formed on the entire surface, a third dyeable resist is applied thereon, and this is patterned and dyed magenta to obtain a magenta layer 9 (FIG. 3 (d)). ). This magenta dyeing has a density half that required by itself. To obtain such a half concentration, the immersion time in the dyeing solution may be halved or the dye concentration of the dyeing solution may be halved.

Thereafter, the intermediate layer 10 and the second yellow layer 1 are subjected to the same steps.
1, the intermediate layer 12 and the second cyan layer 13 are sequentially formed, and finally the overcoat layer 14 as a protective film is formed to complete the color filter forming step.

The order of forming the color filter layers 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.

〔The invention's effect〕

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

Furthermore, when a color filter is formed by two layers of filters, one of them has a band-like shape, and this band-like filter has a width that is half the width of the pixel opening and fits completely within the pixel opening. Since it is arranged like this, there is no change in the spectral characteristics even if the positional deviation between the color filters in the vertical and horizontal directions occurs,
A stable image can be obtained.

Further, according to the method of manufacturing the color solid-state imaging device of the present invention, since the respective color filter layers formed in the width and the positional relationship described above are formed as different layers, the manufacturing can be performed extremely stably. it can.

[Brief description of drawings]

FIG. 1 is a plan view showing a color filter structure of a color solid-state image pickup device according to the present invention, FIG. 2 is a sectional view taken along line AA of FIG. 3, and FIG. 3 is a step showing a method for obtaining the color filter structure of FIG. Another element sectional view, FIG. 4 is a characteristic view showing required spectral characteristics of each dyed layer, FIG. 5 is a sectional view showing a part of the structure of FIG. 1, and FIG.
FIG. 7 is a characteristic diagram showing the spectral characteristic obtained with the structure of FIG. 5, FIG. 7 is a plan view showing a conventional filter structure, FIG. 8 and FIG.
FIG. 10 and FIG. 10 are characteristic diagrams showing actual spectral transmission characteristics of yellow, cyan, and magenta, respectively. 1 ... Substrate, 2 ... Base layer, 5 ... Yellow layer, 6,8,
10,12 ... Intermediate layer, 7 ... Cyan layer, 9 ... Magenta layer, 11 ... Second yellow layer, 13 ... Second cyan layer, 14 ...
… Overcoat layer.

Claims (4)

(57) [Claims] 1. A photosensitive section in which photoelectric conversion sections forming pixels are arranged in a matrix, and magenta and cyan, cyan and green, green and yellow, yellow and magenta having an area of 1/2 in each pixel. In a color solid-state imaging device of a color-difference line-sequential system including a color film composed of a combination, the color filter completely covers the opening of the pixel and a yellow filter and a half of the pixel. And a magenta filter having a density of 2 are alternately formed in the row direction and are overlapped with these, and half the width of the opening of the pixel is formed.
A combination of strip-shaped cyan filters running in the row direction so as to fit within the opening of the pixel.
And a line in which a cyan filter that completely covers the opening of the pixel and a magenta filter of 1/2 density that completely covers the opening of the pixel are alternately formed in the row direction, Second rows, which are overlapped with each other and have a width half the width of the opening of the pixel and which run in the row direction so as to fit in the opening of the pixel, are alternately arranged. A color solid-state imaging device characterized by being installed. 2. A step of forming a transparent flattening layer on a substrate on which a photosensitive pixel portion and a light shielding layer are formed, and a yellow filter and a 1/2 density magenta filter are alternately formed on the flattening layer. Of the yellow, cyan, and half density magenta, the first row is arranged and the second row in which the cyan filter and the half density magenta filter are alternately arranged are arranged alternately. A first dyeing layer is formed in a predetermined pattern that completely covers the openings of the corresponding pixels in each row, and a first intermediate layer and yellow, cyan, 1 /
The second dyed layer of the two-density magenta is formed in a predetermined pattern that completely covers the opening of the corresponding pixel in each row, and the second intermediate layer and the yellow, cyan, and half-density magenta are formed on the second dyed layer. Forming a third dyeing layer in a predetermined pattern that completely covers the openings of the corresponding pixels in each row, and a fourth dyeing layer consisting of a third intermediate layer and yellow.
The cyan and magenta dyed layers have a width half the width of the opening of the pixel in the row in which the layers are alternately formed, and are formed in a predetermined strip-shaped pattern so as to completely fit in the opening of the pixel. A step of forming a fourth intermediate layer and a fifth dyeing layer made of cyan, and having a width of 1/2 of the opening width of the pixel in the row in which the yellow and magenta dyeing layers are alternately formed, And a step of forming a predetermined strip-shaped pattern so that the pixel is completely accommodated in the opening of the pixel. 3. A dye of 1/2 density is obtained by immersing in a dyeing solution for half the time.
Item 7. A method for manufacturing a color solid-state imaging device according to the item. 4. The method for manufacturing a color solid-state image pickup device according to claim 3, wherein the dyeing of 1/2 density is obtained by immersion using a dyeing solution of half density.