JP2003318374A - Solid-state image sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid-state image sensor which is free of peeling and has superior spectral characteristics in spite of fine pixels of ≤4 μm and to provide the solid-state image sensor which has low transmissivity and superior spectral characteristics on the side of a wavelength of >650 nm. <P>SOLUTION: A spectral adjusting function is added to a 1st intermediate layer 2 or/and a 2nd intermediate layer 4. Pigment, dye, or photosensitive material for adding the spectral adjusting function is incorporated. The 1st or/and 2nd intermediate layers are decreased in transmissivities to wavelengths 400 to 450 nm. The 1st or/and 2nd intermediate layers are decreased in transmissivities to the side of a wavelength of >650 nm. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state image pickup device which does not peel off pixels even with a fine color filter and has good spectral characteristics on the wavelength side longer than 650 nm.

[0002]

2. Description of the Related Art In recent years, solid-state image pickup devices such as CCDs and CMOSs mounted in digital cameras and the like have been made higher in pixel size and finer in size. Has become. Further, in general, a solid-state image sensor is provided with a color filter paired with a light-receiving element, and this color filter uses a color resist to form color filter pixels by photolithography. Although there are steppers, aligners, mirror projection aligners, and other exposure machines used for photolithography for forming color filter pixels, steppers are usually used to form color filters for solid-state imaging devices that require high pixel count and miniaturization. It is common.

When mounted on a digital camera or the like, the spectral characteristic required for the color filter of the solid-state image pickup element is the spectral characteristic in the visible region (400 nm to 700 nm). On the other hand, it is not preferable to set the exposure wavelength to the g-line (405 nm) or the h-line (435 nm) at the time of manufacturing the color filter because it is located in the red (R) or yellow (Y) absorption band. Therefore, at the time of manufacturing the color filter, it is possible to form three colors with a single wavelength.
In many cases, a stepper set to i-line (365 nm) outside 700 nm) is used.

With the recent miniaturization of solid-state image pickup devices, the pixel size has become 4 μm or less.
The color filter pixel formed with a thickness of 5 μm has a large aspect ratio, and peeling occurs during development.
Especially, in the primary color blue (B), the i-line transmittance is 1%.
Since it is less than the other colors, which is extremely low compared to the other colors, the i-line does not penetrate to the deep part of the color filter and is hard to be adhered by exposure to curing, so that peeling is noticeable and the yield is deteriorated. Further, when the i-line transmittance is set to 1% or more, the peeling is improved, but in this case, in particular, the short wavelength side spectral characteristic required for blue (B) is deteriorated.

On the long wavelength side, in the conventionally used primary color systems of green (G) and blue (B) and the complementary color system of cyan (C), the wavelength range of 650 nm, which is the red transmission region, is longer than the wavelength range. Has a high transmittance, and since the amount of light is subtracted from the amount of red light, there is a problem that the brightness of red is relatively dark.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and even with a fine color filter of 4 μm or less, pixel peeling is particularly caused in the primary color blue (B). It is an object of the present invention to provide a solid-state imaging device that does not have the above and has excellent spectral characteristics. Further, the present invention provides a solid-state image sensor having excellent spectral characteristics, in particular, in green (G), blue (B), and complementary color cyan (C), which has a low transmittance on the long wavelength side of a long wave of 650 nm or less. This is an issue. Further, even with a fine color filter of 4 μm or less, there is no pixel peeling in the primary color system blue (B) and it has excellent spectral characteristics. At the same time, in particular, green (G), blue (B) ), Complementary color cyan (C)
Has a lower transmittance on the long wavelength side than the long wave of 650 nm,
An object is to provide a solid-state image sensor having excellent spectral characteristics.

[0007]

According to the present invention, a light receiving portion and a charge transfer portion are formed on a semiconductor substrate, and a first intermediate layer, a color filter, a second intermediate layer, and a microlens are sequentially laminated thereon. In the solid-state image pickup device, a spectral adjustment function is added to either or both of the first intermediate layer and the second intermediate layer.

In the solid-state image pickup device according to the above invention, one or both of the first intermediate layer and the second intermediate layer contain an organic resin as a main component, and a pigment for adding a spectral adjustment function, A solid-state imaging device characterized by containing a dye or a photosensitive material.

According to the present invention, in the solid-state image pickup device according to the present invention, one or both of the first intermediate layer and the second intermediate layer is an intermediate layer having reduced transmittance at a wavelength of 400 nm to 450 nm. It is a solid-state imaging device characterized by the above.

In the solid-state image pickup device according to the present invention, one or both of the first intermediate layer and the second intermediate layer are intermediate layers in which the transmittance on the longer wavelength side than a wavelength of 650 nm is reduced. Is a solid-state image sensor.

According to the present invention, in the solid-state image pickup device according to the above-mentioned invention, one or both of the first intermediate layer and the second intermediate layer have a transmittance on a wavelength side of 400 nm to 450 nm and a wavelength longer than 650 nm. It is a solid-state imaging device characterized by being a lowered intermediate layer.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The solid-state image sensor according to the present invention will be described below based on its embodiments. FIG. 1 is a sectional view of an embodiment of a solid-state image sensor according to the present invention. Figure 1
As shown in FIG. 1, this solid-state image sensor has a first intermediate layer (2), a color filter (3), a second intermediate layer (4), on a semiconductor substrate (1) on which a light receiving section and a charge transfer section are formed. The microlenses (5) are sequentially laminated. One of the first intermediate layer (2) and the second intermediate layer (4),
Alternatively, a spectral adjustment function is added to both. Essentially, the first intermediate layer (2) has a flat surface on which the light receiving portion and the charge transfer portion are formed, and the second intermediate layer (4) has a flat surface on which the color filter (3) is formed. It is a face.

The color resist used for forming the color filter pixel has a photolithography characteristic at the time of forming the pixel,
It must satisfy various characteristics such as pigment density (spectral characteristics) after pixel formation. It is necessary to satisfy each characteristic and to add another function, for example, in blue (B), to increase the i-line transmittance for the photoresist as a material and to shorten the formed color filter. It is difficult to make only the color filter, that is, only the color resist, have good spectral characteristics on the wavelength side. In the present invention, another function to be newly added is provided to a layer other than the color filter, that is, one or both of the first intermediate layer (2) and the second intermediate layer (4). is there.

The present invention uses, for example, a pigment, a dye, or a photosensitive material as a material for adding a spectral adjustment function to one or both of the first intermediate layer and the second intermediate layer. Examples of pigments used include azo-based pigments,
Phthalocyanine, indigo, anthraquinone, dioxazine, quinacridone, isoindolinone,
Phthalone-based, methine-based, azomethine-based, metal complex-based, condensed polycyclic, etc. C.I. I. Pigment Color and the like, and inorganic pigments such as milori blue, iron oxide, cobalt violet, manganese violet, ultramarine blue, navy blue, cobalt blue, cerulean blue, pyriadine, emerald green and cobalt green.

As the dye, for example, an azo dye,
Azo metal complex dye, anthraquinone dye, indigo dye, thioindigo dye, phthalocyanine dye, diphenylmethane dye, triphenylmethane dye, xanthene dye, thiazine dye, cationic dye, cyanine dye, nitro dye, quinoline dye, naphthoquinone dye, oxazine dye, etc. Can be mentioned.

The photosensitive material is composed of, for example, a photopolymerizable monomer and a photopolymerization initiator.
Examples of the photopolymerizable monomer include bifunctional monomers such as 1,6-hexadiol diacrylate, ethylene glycol diacrylate, neopentyl glycol diacrylate, and triethylene glycol diacrylate, trimethylol prohasone triacrylate, and pentaerythritol triacrylate. Trifunctional monomers such as acrylate and tris (2-hydroxyethyl) isocyanate,
Examples thereof include polyfunctional monomers such as ditrimethylolpropane tetraacrylate, dipentaerythritol penta, and hexaacrylate.

Examples of the photopolymerization initiator include halomethylated triazine derivatives, halomethylated oxadiazole derivatives, imidazole derivatives, benzoin alkyl ethers, anthraquinone derivatives, benzanthrone derivatives, benzophenone derivatives, acetophenone derivatives, thioxanthone derivatives, Benzoic acid ester derivative,
Examples include acridine derivatives, phenazine derivatives, titanium derivatives and the like. The concentration of these pigments, dyes, and light-sensitive materials is adjusted using one or more kinds, and the concentration is adjusted to be contained in either or both of the first intermediate layer and the second intermediate layer to add a spectral adjustment function.

The color filter is mainly hardened and adhered by using 365 nm i-line, but in the blue (B), the i-line transmittance is less than 1% as described above, as compared with other color filters. Since it was extremely low, the i-line did not penetrate to a deep portion, the adhesion by exposure curing was insufficient, and peeling occurred during development. In order to bring them into close contact with each other, it is necessary to form a color filter using a color resist having a high i-line transmittance, that is, a resist having a low pigment concentration of 20 wt% to 30 wt%. It was extremely difficult to obtain the desired spectral characteristics. Therefore, the spectral adjustment function is added to either or both of the first intermediate layer and the second intermediate layer to obtain the desired spectral characteristics.

On the longer wavelength side, green (G), blue (B), cyan (C), etc. are red transmission regions 650.
The transmittance on the longer wavelength side than nm is higher. Since this amount of light is subtracted from the amount of red light, the brightness of red becomes relatively dark. However, it is difficult to reduce the transmittance on the longer wavelength side than 650 nm without changing the spectral characteristics of 400 nm to 650 nm in green (G), blue (B), and cyan (C). As a means for solving this, in the present invention, either or both of the first intermediate layer and the second intermediate layer are used for spectral adjustment, and green (G), blue (B), and cyan (C) are used. The transmittance on the longer wavelength side than 650 nm was reduced.

[0020]

EXAMPLES Examples of the present invention will be described below. <Example 1> A photosensitive resin (TMR-P3) manufactured by Tokyo Ohka Co., Ltd. was spin-coated on a semiconductor substrate at 900 rp.
m, then hot plate at 180 ° C for 1
Prebaking was performed for 20 seconds to form a first intermediate layer. The photosensitive resin TMR-P3 manufactured by Tokyo Ohka Co., Ltd. used here contains phenol novolac resin as a main component, and contains naphthoquinone diazide sulfonate as a photosensitive material for spectral adjustment. The spectral characteristic of the first intermediate layer is shown as spectrum 1 in FIG.

Then, red (R), green (G), and
Blue (B) color filters were sequentially formed. The pigment of the pigment resist used for each of red (R), green (G), and blue (B) at this time is R: C. I. PR177, C.I. I. P
Y139, G: C.I. I. PG36, C.I. I. PY13
9, C.I. I. PB15: 6, B: C. I. PB15:
6, C.I. I. PV23, and the respective pigment concentrations are R: 40 wt%, G: 35 wt%, and B: 30 wt%. The thickness of the color filter is 1.2 μm.
The spectral characteristic of the blue (B) single layer is shown as spectrum 2 in FIG.

Further, a resin (TOC-1) manufactured by Fuji Yakuhin Co., Ltd. was applied onto the color filter by spin coating at a rotation speed of 1000 rpm, and heat treatment was performed at 200 ° C. for 10 minutes on the hot plate to apply the resin. It was cured to form a second intermediate layer. Finally, a microlens was formed on the second intermediate layer by the well-known heat flow method to manufacture a solid-state image sensor. The spectral characteristics of this solid-state image sensor are shown in FIG.

In order to obtain the desired spectral characteristics with only the color filter, it is necessary to use a pigment resist having a pigment concentration of 35 wt%, but it is difficult to bring them into close contact because the i-ray transmittance is low at less than 1%. . Pigment concentration 30 wt%
Table 1 shows the i-line transmittances of the color filter of No. 1 and the color filter of 35 wt%. Focusing on the spectral characteristic of blue (B), the color filter for obtaining the spectral characteristic 3 which is the target spectral characteristic in a single layer has an i-line transmittance of only 0.5% and is not sufficiently photo-cured to be peeled off. Is occurring. However, by setting the spectral characteristic of blue (B) to spectrum 2,
The i-line transmittance of the blue (B) color filter single layer is 1.8%.
Therefore, peeling does not occur, and by using the first intermediate layer of the spectrum 1, the integrated spectrum of the first intermediate layer and the color filter becomes the spectrum 3 that is the target spectral characteristic.

[0024]

[Table 1]

In Example 1, a phenol novolac resin was used as the main component of the first intermediate layer. However, other resins such as acrylic resin, epoxy resin, polyimide resin, etc. were used without particular attention to phenol novolac resin. You may use the resin containing one or more. Although naphthoquinone diazide sulfonic acid ester is used as the light-sensitive material for spectral adjustment, one or more pigments or dyes having absorption in the range of 400 nm to 450 nm, other light-sensitive materials, or the like may be used. Further, not only the first intermediate layer but also the second intermediate layer or both the first intermediate layer and the second intermediate layer may be provided with the spectral adjustment function.

Example 2 A semiconductor substrate was spin-coated with a coating liquid containing acrylic photosensitive resin as a main component and 1% of a cyanine infrared absorber manufactured by Yamamoto Kasei as a photosensitive material for spectral adjustment. Was applied at 900 rpm and then prebaked at 180 ° C. for 2 minutes with a hot plate to form a first intermediate layer. Figure 3 shows the spectral characteristics of the first intermediate layer.
Is shown as spectrum 4. Subsequently, red (R) is formed on the first intermediate layer by photolithography using a pigment resist,
Green (G) and blue (B) color filters were sequentially formed.
The film thickness of the color filter is 1.2 μm. The spectral characteristics of the green (G) and blue (B) single layers are shown as spectrum 5 and spectrum 6 in FIG.

Further, a resin (TOC-1) manufactured by Fuji Yakuhin Co., Ltd. was applied to the color filter by spin coating at a coating speed of 1000 rpm, and the temperature was 200 ° C. on a hot plate.
Was heat-treated for 10 minutes to cure the resin and form a second intermediate layer. Finally, a microlens was formed on the second intermediate layer by the well-known heat flow method to manufacture a solid-state image sensor. The spectral characteristics of this solid-state image sensor are shown in FIG. Focusing on the spectral characteristics of green (G) and blue (B), green (G)
And 650n in the spectrum of the blue (B) color filter single layer
Although the bottom from m to 700 nm is floating, when the spectral adjustment function is added to the first intermediate layer, the spectral characteristics of green (G) and blue (B) are spectrum 7 and spectrum 8 at 650 nm.
It can be seen that the bottom transmittance decreases to ˜700 nm and becomes flat.

Although the acrylic resin is used as the main component of the first intermediate layer in the second embodiment, one or a plurality of other resins such as epoxy resin and polyimide resin may be used without particular attention to the acrylic resin. A resin containing it may be used. Although the cyanine-based infrared absorber is used as the light-sensitive material for spectral adjustment, one or more other pigments or dyes having absorption at 650 nm to 700 nm, other light-sensitive materials, or the like may be used. Further, not only the first intermediate layer but also the second intermediate layer or both the first intermediate layer and the second intermediate layer may have the spectral adjustment function.

In addition to the applications of Examples 1 and 2, either one or both of the first intermediate layer and the second intermediate layer are used to adjust the spectral characteristics by lowering the transmittance in a certain limited wavelength region. It is possible to add a spectral adjustment function to.

[0030]

INDUSTRIAL APPLICABILITY According to the present invention, one or both of the first intermediate layer and the second intermediate layer are made to have a spectral adjustment function of, for example, containing a pigment to reduce the transmittance at a wavelength of 400 nm to 450 nm. Therefore, even with a fine color filter having a size of 4 μm or less, the solid-state image pickup element does not have pixel peeling in the primary color blue (B) and has excellent spectral characteristics.

Further, the present invention has a spectral adjustment function of reducing the transmittance at a wavelength longer than 650 nm by including, for example, a pigment in one or both of the first intermediate layer and the second intermediate layer. Since it is added, the solid-state image sensor having excellent spectral characteristics, in particular, in green (G), blue (B), and complementary color cyan (C), has a low transmittance on the longer wavelength side than the wavelength of 650 nm. Furthermore, the function of the infrared cut filter to reduce noise, namely,
By providing a function of absorbing light in the near-infrared region, a solid-state image sensor with higher added value can be obtained.

In the present invention, one or both of the first intermediate layer and the second intermediate layer contain a pigment, for example, and have a wavelength of 400 nm to 450 nm and a wavelength of 650.
Since a spectral adjustment function for lowering the transmittance on the wavelength side longer than nm is added, even with a fine color filter of 4 μm or less, there is no pixel peeling especially in the primary color blue (B), and it is excellent. A solid-state image sensor having spectral characteristics and, at the same time, excellent spectral characteristics with a low transmittance on the longer wavelength side than a wavelength of 650 nm in green (G), blue (B), and complementary color cyan (C). .

Further, according to the present invention, when the spectral characteristic of the color filter has a slight deviation from the desired spectral characteristic, for spectral adjustment to the first intermediate layer or the second intermediate layer, for example, By adjusting the type and amount of the pigment, it is possible to correct the target spectral characteristics. Therefore, it is possible to inexpensively obtain various required spectral characteristics by using the same color resist.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of a solid-state image sensor according to the present invention.

FIG. 2 is an explanatory diagram of spectral characteristics in the first embodiment.

FIG. 3 is an explanatory diagram of spectral characteristics in the second embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Semiconductor substrate 2 ... 1st intermediate | middle layer 3 ... Color filter 4 ... 2nd intermediate | middle layer 5 ... Micro lens spectroscopy 1 ... Spectral characteristic of the 1st intermediate | middle layer in Example 1 Spectral spectrum 2 ... Spectral characteristic spectrum of blue (B) single layer in Example 1 ... Integrated spectral characteristic spectrum 4 of first intermediate layer and blue (B) single layer in Example 1 ... Example 2 Spectral characteristic spectrum 5 of the first intermediate layer in Example 2 ... spectral characteristic spectrum of the green (B) single layer in Example 2 ... spectral characteristic spectrum 7 of the blue (B) single layer in Example 2 Integral spectral characteristics of the first intermediate layer and the green (B) single layer in Example 2 Spectroscopy 8 ... Integral spectral characteristics of the first intermediate layer and the blue (B) single layer in Example 2

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Claims (5)

[Claims] 1. A solid-state imaging device comprising a semiconductor substrate on which a light receiving portion and a charge transfer portion are formed, and on which a first intermediate layer, a color filter, a second intermediate layer, and a microlens are sequentially laminated. One of the one intermediate layer and the second intermediate layer,
Alternatively, a solid-state image pickup device characterized by adding a spectral adjustment function to both. 2. One or both of the first intermediate layer and the second intermediate layer contains an organic resin as a main component and contains a pigment, a dye, or a light-sensitive material that adds a spectral adjustment function. The solid-state image sensor according to claim 1. 3. The method according to claim 1, wherein one or both of the first intermediate layer and the second intermediate layer is an intermediate layer having a reduced transmittance at a wavelength of 400 nm to 450 nm. 2. The solid-state image sensor according to 2. 4. The one or both of the first intermediate layer and the second intermediate layer are intermediate layers having reduced transmittance on the longer wavelength side than a wavelength of 650 nm, or The solid-state image sensor according to claim 2. 5. One or both of the first intermediate layer and the second intermediate layer are intermediate layers having a reduced transmittance on the longer wavelength side than wavelengths of 400 nm to 450 nm and 650 nm. The solid-state imaging device according to claim 1 or 2.