JPH0442966A - Solid-state colored image sensing element - Google Patents

Abstract

PURPOSE:To make it possible to inhibit an irregularity by colors in a condensing rate by a method wherein the radiuses of curvature of a plurality of condensing lenses for making incident light condense are respectively set at a prescribed value according to the hue of each photoelectric conversion region. CONSTITUTION:Photodiodes 11 are formed in a semiconductor substrate 10 and a transparent resin layer 18 is applied on monochromatic solid-state image sensing elements. Then, a film to be dyed is applied on the layer 18, is patterned, is dyed into a necessary color and is fixed. At the time of the patterning, a focal point is shifted in a (+) or (-) direction to expose in the setting of a defocus without exposing in such a way that the focal point is adjusted on the film to be dyed, whereby patterns having the sag shape of a pattern edge can be formed. By dyeing and fixing, a colored lens 1 can be formed into the shape of a lens having a certain radius of curvature. Accordingly, by adjusting the amount of shift of the focal point of an aligner at the time of the patterning and dyeing conditions, the radiuses of curvature of condensing lenses can be respectively set at a prescribed value.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a color solid-state image sensor.

[Conventional technology]

Conventionally, as a color solid-state imaging device with high sensitivity and no color mixture, there is one disclosed in, for example, Japanese Patent Laid-Open No. 61-203663. FIG. 3 is a cross-sectional view showing a conventional color solid-state image sensor disclosed in the publication. In the figure, IO is a semiconductor substrate, 11 is a photoelectric conversion region such as a photodiode, 12 is a signal readout region, and 13 is a Light shielding layer, 15.16
．． 11 is a color filter, 18 is a photosensitive transparent resin flat layer, 1
9 is a lens layer.

Next, the manufacturing method will be explained.

Fig. 3 shows a color filter 15, 16, 17 and a lens layer 19 formed on an ordinary CCD interline type solid-state image sensor. It is formed by dyeing the layers red 15, green 16, and blue 17 using lithography technology. After forming these color filters 15, 16, and 17, a resin layer 18 is formed as a protective film for these color filters. Finally, the resin that will become the lens layer 19 is provided by patterning heat flow to form the lens layer 19.

The incident light is focused into the photoelectric conversion region by adjusting the radius of curvature of the lens layer 19 and the thickness of the resin layer 18.

[Problem to be solved by the invention]

As described above, the conventional color solid-state image sensor passes all incident light (white light containing countless wavelengths) through the lens layer having the same radius of curvature and the color filter 15, 16, 17 to the photoelectric conversion region 11. However, since the refractive index of the light is different for each wavelength, for example, red light (long wavelength side) and light from the front thread (short wavelength side), it is difficult to actually focus the light. The incident light has a different focusing rate depending on the wavelength.
In particular, the light from the front thread (on the short wavelength side) has a smaller refractive index than red light, so it is difficult to focus, and the photodiode, which is the commonly used charge conversion unit 11, has a lower sensitivity for the front thread. Because of the low
There was a problem that /N deteriorated.

This invention was made to solve the above-mentioned problems, and its purpose is to provide a high-precision color solid-state imaging device that can obtain a desired light collection rate regardless of the color of incident light. shall be.

[Means to solve the problem]

In the color solid-state image sensor according to the present invention, the radius of curvature of a plurality of condensing lenses provided corresponding to photoelectric conversion regions for condensing incident light is set to a predetermined value according to the hue of each photoelectric conversion region. It is set to .

Further, in the color solid-state imaging device according to the present invention, the condenser lens is further colored in accordance with the hue of each of the photoelectric conversion regions.

[Effect]

In the color solid-state image sensor of the present invention, since the condensing lens has a predetermined radius of curvature for each color layer, a desired condensing rate can be obtained according to each hue, and the condensing lens can be condensed according to the wavelength of the incident light. The difference in rate G) can be adjusted, and the same high light collection rate can be obtained regardless of the wavelength.

Furthermore, since each of the condensing lenses is colored in accordance with the hue of the photoelectric conversion region, unnecessary light is absorbed by the lens portion and is not focused on the photoelectric conversion portion.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the configuration of a color solid-state image sensor according to an embodiment of the present invention, in which 10 is a semiconductor substrate;
11 is a photoelectric conversion area such as a photodiode, 12 is a signal readout area, 13 is a light shielding layer, 1.2.3
18 is a condensing lens, and 18 is a transparent resin layer.

Next, the manufacturing method of this example will be explained.

First, a transparent resin layer 18 is coated on a so-called monochrome solid-state image sensor in which a photodiode 11, a signal readout area 12, etc. are formed on a semiconductor substrate 10. This transparent resin layer 1
It is desirable that 8 has a thickness of at least 1 μm or more.

Next, a film to be dyed (e.g. gelatin containing ammonium dichromate) is applied on the transparent resin layer 18 and patterned using lithography technology to obtain the desired color (e.g. red).
dye.

After dyeing, a fixation method is used to fix the pattern to prevent it from being dyed with other colors.

At the time of patterning, for example, when patterning is performed using a reduction exposure device, the focus is shifted in the (+) or (-) direction instead of being exposed so that the dyed film is in focus. By exposing with the settings, a pattern with a rounded pattern edge can be formed.

In addition, by dyeing and fixing, swelling, which is determined by the dye used, the dyed film, the dyeing conditions, etc., occurs uniformly on the surface of the dyed film pattern, so the colored lens 1 is formed into a lens shape with a certain radius of curvature. Can be formed.

Therefore, when patterning the film to be dyed using lithography technology and dyeing it in the desired color, the radius of curvature of the condenser lens can be adjusted to a predetermined value by adjusting the amount of focus shift of the exposure device during patterning and the dyeing conditions. It can be set to 4fi, and can be adjusted to obtain the desired light collection rate for dyeing 1 to orange. That is, for example, the light collection rate can be set to be maximum for dyeing 1-7 yellow.

Note that the radius of curvature of this colored lens 1 corresponds to the coloring film.

Even if the dye is changed, it can be controlled by the dyeing conditions and the focus shift position (blur amount).

In addition, the other condensing lenses 2 and 3 go through the same process,
The colored lens has its radius of curvature adjusted so as to obtain the desired light collection rate corresponding to each color.

In this embodiment, each lens layer 1,
2.3 Radius of curvature 4-1 The desired light condensing rate was adjusted for the color of each lens layer, and the condensing rate was set individually corresponding to each hue. Therefore, it is possible to set only a specific hue to have the maximum light collection rate, or to obtain the same high light collection rate for all incident light, which can solve the problem of incident light in the past. It is possible to adjust variations in the light collection rate due to variations in the refractive index of the wavelength (color) of light.

In addition, in this example, since the 1-light lenses 1.2°3 are colored in accordance with the hue of the photoelectric conversion area, the colors required by the 1/lenses 1 and 2.3 are different from each other. Since the light is not absorbed, it is possible to reduce the stray light component to the signal readout region 12 caused by the difference in the refractive index of the incident light.

In the above example, the dyed film was individually coated and patterned, but several dyed film patterns may be formed at once in the same process. In this case, as shown in FIG. Then, a resist mask 20 is applied to the upper layer and dyed.

Further, the adjustment of the radius of curvature of this 1/ns is performed by adjusting the dyeing conditions etc. in the same manner as in the above embodiment.

Further, in the above embodiment, the case where the hue is three colors is shown as an example, but the present invention is not particularly limited to three colors,
Various hue combinations are possible depending on the element, and even in this case, the same effect as in the above embodiment can be achieved.

Furthermore, in the above example, the lens 1.2.3 was colored using a dyeing method, but these colored lenses 1.2.
．． 3 may be formed by thermally flowing a resin in which a material or the like is dispersed.

〔Effect of the invention〕

As described above, according to the present invention, the hue of the photoelectric conversion area can be adjusted according to 1. By changing the radius of curvature of the condensing lens and forming each 1/lens independently into an optimal shape with a predetermined condensing rate, the condensing rate caused by the difference in the refractive index of each wavelength (color) can be reduced. This has the effect of suppressing color variations.

In addition, since the condensing lens is colored to correspond to the hue of each photoelectric conversion area, it is possible to prevent unnecessary light from entering the signal readout area due to the difference in the refractive index of the incident light, and to prevent stray light from entering the signal readout area. It has the effect of reducing

[Brief explanation of drawings]

FIG. 1 is a diagram showing a color solid-state image sensor according to an embodiment of the present invention, FIG. 2 is a diagram showing a part of the manufacturing process of a color solid-state image sensor according to another embodiment of the invention, and FIG. 3 is a diagram showing a conventional color solid-state image sensor. FIG. 2 is a diagram showing a color solid-state image sensor. 1゜2.3 is a condensing lens, IO is a semiconductor substrate, 11 is a photoelectric conversion region, 12 is a signal readout region, 13 is a light shielding film,
15, 16, and 17 are color filters, 18 is a transparent resin flat layer, 19 is a lens layer, and 20 is a resist mask. In the figures, the same reference numerals indicate the same or equivalent parts.

Claims (2)

[Claims] (1) A photoelectric conversion area formed in a mosaic shape on the same semiconductor substrate, a signal readout area for reading out a signal photoelectrically converted in the photoelectric conversion area, and condensing incident light corresponding to the photoelectric conversion area. A color solid-state imaging device comprising a plurality of condensing lenses, each of the condensing lenses having a predetermined radius of curvature corresponding to the hue of each photoelectric conversion region. element. (2) The color solid-state image sensor according to claim 1, wherein each of the condensing lenses is colored in accordance with the hue of each of the photoelectric conversion regions.