JPH10197713A - Black matrix and color filter formed by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide black matrices which are thin films, have a high optical density and low reflectivity and have the resistance to a peeling liquid for colored pattern materials and the resistance to a washing liquid and color filters formed by using the same. SOLUTION: The surface of a transparent substrate 1 is provided with light shielding layers 4 consisting of metal silicide and the black matrices 5 composed of antireflection layers 2, 3 consisting of oxidized or nitrided metal silicide. The color filters are formed by providing the surface of the transparent substrate 1 formed with the black matrices 5 with at least three colors of colored patterns 6R, 6G, 6B. The metals which constitute the metal silicide described above or the oxidized or nitrided metal silicide are transition metals. These transition metals are the metals selected from a group consisting of Zr, Ta, Mo, W, Hf, Ti and Ni.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color filter for color separation used in a color liquid crystal display device and the like, and more particularly to a color filter provided with a black matrix in a gap between colored patterns for improving display contrast.

[0002]

2. Description of the Related Art Heretofore, a black matrix for a color filter used in a color liquid crystal display device or the like has generally been produced by etching a metal chromium film using a photolithography method.

[0003] However, alternative materials to metallic chromium have been studied from the viewpoint of low reflection and low cost of the black matrix. Among them, there is a method of manufacturing a black matrix using a black resin in which carbon black is dispersed as a method put into practical use. The black matrix obtained in this manner has a lower reflectance than the metal chromium film, so that the display contrast of the color liquid crystal display device can be improved and the cost can be reduced.

However, the resin black matrix has a lower optical density than chromium metal, and it is necessary to increase the film thickness in order to obtain a sufficient optical density. Thereby, the overlapping step between the resin black matrix and the colored pattern is also increased. In the case of a color liquid crystal display device, this step may cause a problem such as a defect in rubbing, a defect in alignment of liquid crystal, or a break in the ITO film thereon.

In order to solve this problem, a graphite black matrix in which graphite is dispersed has been disclosed in Japanese Patent Laid-Open No. 6-11613.
No. 1993. Since graphite is a scale-like crystal, a high optical density can be obtained in a thin film, and the above problem can be reduced.

However, the graphite black matrix also has
There is a problem that the reflectance is high. That is, since graphite is a scaly crystal, when applied on a substrate, individual crystals reflect incident light in a mirror-like manner, so that the overall reflectance increases. The reflectance of a resin black matrix using carbon black is about 1%, whereas the reflectance of a graphite resin black matrix is about 10%, which may lower the display contrast of a liquid crystal display device.

Since graphite has a higher optical density than other black pigments, it cannot be dispersed in a photosensitive resin and patterned by the photolithography method as in the case of using other black pigments. Must be used. The lift-off method is generally applied to a very thin film (0.1 μm) formed by vacuum film formation.
m or less). When patterning a relatively thick film (about 0.3 to 0.5 μm) formed by spin coating, roll coating, or the like as in this case, the edge of the underlying resist pattern is patterned. There is also a problem that chipping and peeling are likely to occur in portions, and sufficient resolution cannot be obtained.

On the other hand, from the viewpoint of manufacturing cost, a method of peeling off and cleaning the color pattern, forming a color pattern on the black matrix again, and regenerating the black matrix has been performed. Therefore, the black matrix is required to have the resistance to the stripping solution of the colored pattern material and the cleaning solution. However, in the case of metal materials, it has not been easy to find a black matrix material having a conventional stripping liquid resistance and a cleaning liquid resistance comparable to that of chromium.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve such problems, and it is an object of the present invention to provide a thin film having a high optical density, a low reflectance and a colored pattern. It is an object of the present invention to provide a black matrix and a color filter having resistance to a stripping liquid of a material and resistance to a cleaning liquid.

[0010]

Means for Solving the Problems In order to solve the above-mentioned problems in the present invention, first, in a color filter comprising a black matrix and at least three colored patterns on a transparent substrate, the black matrix is It is composed of a light shielding layer and an anti-reflection layer,
The light shielding layer is made of a metal silicide, which is a black matrix.

According to a second aspect of the present invention, there is provided the black matrix according to the first aspect, wherein the antireflection layer comprises at least one layer of oxidized or nitrided metal silicide.

According to a third aspect of the present invention, there is provided the black matrix according to the first or second aspect, wherein the metal constituting the metal silicide is a transition metal.

According to a fourth aspect of the present invention, the transition metal is a metal selected from the group consisting of Zr, Ta, Mo, W, Hf, Ti and Ni.
A black matrix according to any one of claims 3 to 3.

According to a fifth aspect of the present invention, at least three colored patterns are formed on the transparent substrate on which the black matrix according to any one of the first to fourth aspects is formed. This is a color filter characterized by the above.

[0015]

Embodiments of the present invention will be described below in detail. FIG. 1 shows a cross-sectional configuration of an embodiment of a black matrix of the present invention and a color filter using the same.
(A) and (b) show. FIG. 1A shows a structure in which a light-shielding layer 4 made of metal silicide and an anti-reflection layer 2, 3 made of oxidized or nitrided metal silicide are provided on a transparent substrate 1. Depending on the specifications of the optical characteristics of the black matrix 5, the antireflection layer may be a single-layer metal silicide. FIG. 1B shows at least three colored patterns 6R and 6G on the transparent substrate 1 on which the black matrix is formed.
6B to form a color filter.

The metal constituting the metal silicide or the oxidized or nitrided metal silicide is a transition metal. Further, the transition metal is Zr, Ta, Mo,
It is a metal selected from the group consisting of W, Hf, Ti and Ni.

For example, metal silicide has been studied for its physical properties as an electrode / wiring material replacing polysilicon in an integrated circuit (for example, Ref. (1) Kyoichi Suguro, Iwao Kunishima: current state and problems of metal silicide technology, surface science, etc.). vol.16, No.
4, p.224, 1995). One of its features is that it has excellent oxidation resistance and thermal stability and has higher resistance to heating chemicals than ordinary metals.

In recent years, metal silicide has been used as a material for a halftone type phase shift mask by forming a film as an oxide or a nitride by controlling the optical properties by so-called reactive sputtering in which oxygen or nitrogen is added to argon. (For example, Ref. (2) Mulberry Principle: Forefront of Lithography Technology (1): Mask Technology, Oplus E, No. 1
82, p.92, 1995).

Regarding the optical characteristics of the black matrix, the reflectance (hereinafter abbreviated as R) in the visible light region (wavelength 400 to 700 nm) is low, and the optical density (hereinafter abbreviated as od) is also in the visible light region. High (or low transmittance (hereinafter abbreviated to T as appropriate)) is required. The optical density od and the transmittance T have the relationship of the following equation. od = −log ₁₀ T

In order to satisfy the above-mentioned optical characteristics in a wide wavelength range like a black matrix, the refractive index and the extinction coefficient of each layer gradually change with respect to the wavelength (that is, the wavelength dispersion of the optical constant is small). The fact that the metal constituting the metal silicide is a transition metal is suitable for this requirement. Transition metals are further narrowed down from the viewpoint of the suitability for patterning by etching.

By the way, optical characteristics such as transmittance and reflectance of a thin film at a certain wavelength include a refractive index (hereinafter abbreviated as n) and an extinction coefficient (hereinafter abbreviated as k) at that wavelength, where n and k are generally optical constants. ) And film thickness (hereinafter abbreviated as d)
The same applies to a multilayer film (for example, reference (3) Sakae Kanehara, thin film, (Shokabo) p.197). Therefore, if n, k, and d of the thin film of each layer are known, the transmittance and the reflectance of the entire multilayer film can be obtained by calculation.

The metal silicide multilayer film designed and formed by the above method is subjected to a patterning process by a usual photolithography method to form a black matrix 5. Next, the coloring patterns 6R and 6 of the three primary colors of red, green and blue
G and 6B are formed. This colored pattern 6R, 6G, 6
As a method for forming B, any of a pigment dispersion method, a dyeing method, a printing method, and an electrodeposition method may be used, and it may be appropriately selected from the above methods according to various characteristics required for a color filter.

[0023]

The present invention will be described in detail with reference to the following examples. <Embodiment 1> Here, an embodiment will be described in which a light shielding layer and an antireflection layer are formed using Ta metal as a transition metal constituting metal silicide, a black matrix is manufactured, and a color filter is manufactured. Here, the target of the optical characteristics of the black matrix is 5% or less even at the wavelength at which the reflectance R becomes the maximum, and 3.5 or more at the wavelength at which the optical density od becomes the minimum.

First, a TaSi film was formed on a transparent substrate by sputtering using TaSi ₂ as a target and Ar (15 sccm) as a carrier gas. Further, on another transparent substrate, TaSi ₂ is targeted, and Ar (1
A TaSiO film was formed by reactive sputtering in which oxygen gas (3 sccm) was added to 2 sccm). Further, TaSi ₂ is targeted on another transparent substrate, and A
A TaSiN film was formed by reactive sputtering in which nitrogen gas (2 sccm) was added to r (13 sccm). The RF power at the time of these film formations is 200 W in all cases.

The optical constants of the three-layer film are set to wavelengths 400 and 55.
FIG. 2 shows the results of measurement with an ellipsometer at 0 and 700 nm.

FIG. 2 shows that the TaSi film and the TaSiO
When a black matrix is made with a three-layer structure of a film and a TaSiN film, the reflectance R can be reduced most in the visible light region,
Moreover, when the film thickness of each layer capable of securing the optical density od of 3.5 or more was obtained, the following results were obtained. Thickness of TaSi ... 1300 Thickness of TaSiN ... 133 Thickness of TaSiO ... 470

From the above results, individual film forming conditions and film thicknesses satisfying the optical characteristics of the black matrix composed of the three-layered film using Ta metal as the transition metal could be set.

Next, on the transparent substrate 1 under the above film forming conditions,
TaSiO film with thickness of 470 °, TaSi with thickness of 133 °
An N film and a 1300 ° -thick TaSi film are sequentially formed.
A layer film was formed.

Next, a photoresist was applied on the three-layered film, exposed and developed in a predetermined pattern to form a resist pattern. Further, dry etching is performed by using the resist pattern as a mask, and patterning is performed to form an antireflection layer 2 made of a TaSiO film, an antireflection layer 3 made of a TaSiN film, and a light shielding layer 4 made of a TaSi film.
Was formed, and a black matrix 5 of the present invention was obtained (see FIG. 1A). Further, in order to examine the suitability of the color filter for the regeneration step, the film of each layer was immersed in a colorant stripper, but no change in film quality was observed.

The reflectivity R of this three-layer black matrix
FIG. 3 shows the results of measuring the spectral characteristics of the optical density od and the optical density od. As can be seen from FIG. 3, the reflectance R is 400 to 70.
It was 2% or less in the wavelength region of 0 nm, and the optical density was 3.5 or more, and sufficient optical characteristics as a black matrix were obtained.

Next, a red pigment-dispersed resist is applied on the transparent substrate 1 on which the black matrix 5 is formed, and is subjected to patterning such as exposure, development, and post-baking in a predetermined pattern to form a red colored pattern 6R. Formed. Similarly, green and blue colored patterns 6G and 6B were sequentially formed to obtain a color filter of the present invention (FIG. 1B).
reference).

<Embodiment 2> Here, an embodiment will be described in which a light shielding layer and an antireflection layer are formed using Zr metal as a transition metal constituting metal silicide to form a black matrix, and a color filter is formed. Here, the target of the optical characteristics of the black matrix is 5% or less even at the wavelength at which the reflectance R becomes the maximum, and 3.5 or more at the wavelength at which the optical density od becomes the minimum.

First, a ZrSi film was formed on a transparent substrate by sputtering using ZrSi ₂ as a target and Ar (15 sccm) as a carrier gas. Further, ZrSi ₂ is targeted on another transparent substrate, and Ar (1
A ZrSiN film (1) was formed by reactive sputtering in which nitrogen gas (2 sccm) was added to 3 sccm).
Further, a ZrSiN film (2) is formed on another transparent substrate by reactive sputtering using ZrSi ₂ as a target and adding nitrogen gas (1 sccm) to Ar (14 sccm).
Was formed. The RF power during these film formations was 20
0W.

The optical constants of the three-layer film are set to wavelengths 400 and 55.
FIG. 4 shows the results of measurement with an ellipsometer at 0 and 700 nm.

FIG. 4 shows that the ZrSi film and the ZrSiN
(1) When a black matrix is formed with a three-layer structure of a film and a ZrSiN (2) film, the film thickness of each layer capable of reducing the reflectance R in the visible light region and securing the optical density od3.5 or more is determined. The following results were obtained. ZrSi film thickness ··· 1300 mm ZrSiN (2) film thickness · · 229 mm ZrSiN (1) film thickness · · · 249 mm

From the above results, individual film forming conditions and film thicknesses satisfying the optical characteristics of a black matrix composed of a three-layer film using Zr metal as the transition metal could be set.

Next, on the transparent substrate 1 under the above film forming conditions,
ZrSiN (1) film with a thickness of 249２４, Zr with a thickness of 229Å
An SiN (2) film and a 1300 ° -thick ZrSiN film were sequentially formed to form a three-layer film.

Next, a photoresist was coated on the three-layered film, exposed and developed in a predetermined pattern to form a resist pattern. Further, dry etching is performed using the resist pattern as a mask to form an antireflection layer 2 made of a ZrSiN (1) film, an antireflection layer 3 made of a ZrSiN (2) film, and a light shielding layer 4 made of a ZrSi film. Was obtained (see FIG. 1A). Further, in order to examine the suitability of the color filter for the regeneration step, the film of each layer was immersed in a colorant stripper, but no change in film quality was observed.

The reflectivity R of this three-layer black matrix
FIG. 5 shows the results of measuring the spectral characteristics of the optical density od and the optical density od. As can be seen from FIG. 5, the reflectance R is 420 to 70.
The optical density was approximately 4% or less in the wavelength region of 0 nm, and the optical density was 3.5 or more in the wavelength region of 400 to 700 nm, and sufficient optical characteristics as a black matrix were obtained.

Next, a red pigment-dispersed resist is applied on the transparent substrate 1 on which the black matrix 5 is formed, and is subjected to patterning processing such as exposure, development, post-baking, etc. in a predetermined pattern to form a red colored pattern 6R. Formed. Similarly, green and blue colored patterns 6G and 6B were sequentially formed to obtain a color filter of the present invention (FIG. 1B).
reference).

[0041]

Since the black matrix of the present invention and the color filter using the same have the above-described structure, the following effects can be obtained. That is, according to the first aspect of the present invention, since the light-shielding layer is made of metal silicide, the colored pattern material has resistance to a stripping liquid and cleaning liquid. According to the invention according to claim 2, the antireflection layer is made of at least one layer of oxidized or nitrided metal silicide. Can be changed to control the optical characteristics. According to the third aspect of the present invention, since the metal constituting the metal silicide is a transition metal, the optical characteristics of the black matrix are realized over a wide wavelength range of almost the entire visible light range. Further, according to the invention of claim 4, the transition metal is Z
Since the metal is selected from the group consisting of r, Ta, Mo, W, Hf, Ti, and Ni, etching for patterning is easy. Further, according to the invention according to claim 5, since the color filter composed of at least three colored patterns formed on the black matrix can realize a low reflectance and a high optical density in a thin film as a whole over the black matrix, A color filter having a smooth surface can be provided. Further, by incorporating the color filter of the present invention into a color liquid crystal display device, a color liquid crystal display device having excellent display characteristics can be obtained.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view illustrating a configuration of an embodiment of a black matrix according to the present invention. (B) is a sectional view showing a configuration of an embodiment of the color filter of the present invention.

FIG. 2 is an explanatory diagram showing measured values of optical constants of a light shielding film and an anti-reflection film constituting a black matrix according to the first embodiment of the present invention.

FIG. 3 is an explanatory diagram illustrating spectral characteristics of a black matrix according to the first embodiment of the present invention.

FIG. 4 is an explanatory diagram showing measured values of optical constants of a light shielding film and an antireflection film constituting a black matrix according to a second embodiment of the present invention.

FIG. 5 is an explanatory diagram illustrating spectral characteristics of a black matrix according to Example 2 of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Transparent substrate 2, 3 ... Anti-reflection layer 4 ... Light shielding layer 5 ... Black matrix 6R ... Red coloring pattern 6G ... Green coloring pattern 6B ... Blue coloring pattern 7 ... Incident light 8 …… Reflected light 9 …… Transmitted light

Claims (5)

[Claims] 1. A color filter comprising a black matrix and at least three colored patterns on a transparent substrate, wherein the black matrix comprises a light-shielding layer and an antireflection layer, and the light-shielding layer comprises a metal silicide. Black matrix to feature. 2. The black matrix according to claim 1, wherein said antireflection layer comprises at least one layer of oxidized or nitrided metal silicide. 3. The black matrix according to claim 1, wherein the metal constituting the metal silicide is a transition metal. 4. The transition metal is Zr, Ta, Mo, W, H
The black matrix according to any one of claims 1 to 3, wherein the black matrix is a metal selected from the group consisting of f, Ti, and Ni. 5. A color filter, wherein at least three colored patterns are formed on a transparent substrate on which the black matrix according to claim 1 is formed. .