JPH11223811A - Black mask, color filter, and liquid crystal display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the black mask which can be improved in surface reflectivity and etching characteristics, and the color filter and liquid crystal display using it. SOLUTION: This black mask is made of oxide, nitride, carbide, oxidized nitride, oxidized carbide, nitrified carbide, or oxidized nitrified carbide of at least one kind of metal selected from a group of chromium, molybdenum, tungsten, nickel, and germanium and is formed by stacking 1st and 2nd reflection preventive films 3 and 4 differing in composition and a lightproof film 5 made of at least one kind of metal selected from the group of chromium, molybdenum, tungsten, nickel, and germanium on a transparent substrate 2 in order so that the metals that the reflection preventive films 3 and 4 and lightproof film 5 contain are mutually different and at least one of the films 3, 4, and 5 contains chromium.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a black mask,
The present invention relates to a color filter and a liquid crystal display.

[0002]

2. Description of the Related Art A color liquid crystal display of the STN type or the TFT type is provided with a color filter at a position facing a liquid crystal layer. The color filter has a colored resin separated by a black mask having a plurality of openings, and the characteristics of the black mask affect the visibility of the liquid crystal display. Conventional black masks
JP-A-8-179301, JP-A-8-36171
And JP-A-9-243801.

[0003]

In a color filter used in a liquid crystal display, in order to improve the visibility of the panel, the light reflectance on the surface of a black mask, which is one of the components, and the color filter in the visible wavelength region are required. It is required to reduce the wavelength dependence of the reflectance, that is, to sufficiently reduce the wavelength characteristics of the reflectance (reduce the amplitude of the reflectance at each wavelength).

In the black mask described in Japanese Patent Application Laid-Open No. Hei 8-179301, all layers include the same kind of metal. That is, the black mask described in the publication has a first chromium-based antireflection film, a second chromium-based antireflection film, and a chromium-based light-shielding film sequentially laminated. More specifically, the first chromium-based antireflection film contains Cr, O, N, and C, and the second chromium-based antireflection film contains Cr, N,
It contains O and C, and the chromium-based light shielding film contains only metallic chromium. However, the wavelength dependence of the surface reflectance of the black mask is still large, and the reflectance is not sufficiently reduced.

In the black mask described in Japanese Patent Application Laid-Open No. 8-36171, the first chromium-based antireflection film is mainly composed of chromium and oxygen, and the second chromium-based antireflection film is mainly composed of chromium and nitrogen. Although the light-shielding film is mainly composed of chromium metal, the etching rates of these films vary considerably. The value varies depending on the conditions at the time of film formation. However, when the etching rate when the light-shielding film mainly composed of metallic chromium is wet-etched using an etching solution such as ceric ammonium nitrate is set to 1, chromium and oxygen The etching rate of the first chromium-based anti-reflection film mainly containing chromium and nitrogen is about 0.5 or less, and the etching rate of the second chromium-based anti-reflection film mainly containing chromium and nitrogen is about 5 or less.
That is all. Therefore, when the black mask having the three-layer structure is wet-etched, a precise pattern cannot be formed due to a difference in etching rate between these films.

[0006] The black mask described in JP-A-9-243801 does not contain a chromium component.
As in the case of three-layer wet etching, formation of a precise pattern is not always sufficient.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and can improve the etching property at the time of manufacturing, and greatly exceed the characteristics of the black mask formed by the above-mentioned conventional technique. It is an object of the present invention to provide a black mask having a low reflectance over the entire visible region and a small wavelength dependence of the reflectance, a color filter capable of obtaining a clear image, and a liquid crystal display.

[0008]

The black mask according to the present invention comprises chromium (Cr), molybdenum (Mo), tungsten (W), nickel (Ni) and germanium (G).
e) oxide, nitride, carbide, oxynitride, oxycarbide, nitrided carbide, or oxynitridecarbide of at least one same metal selected from the group consisting of:
First and second anti-reflection films having different compositions and a light-shielding film made of at least one metal selected from the group consisting of chromium, molybdenum, tungsten, nickel, and germanium are included in the anti-reflection film and the light-shielding film. The layers are sequentially laminated on a transparent substrate such that different metals are used and at least one of these films contains chromium. In particular, it is preferable that both the first and second antireflection films are made of a tungsten compound, and the light-shielding film is made of chromium.

[0009] The black mask according to the present invention can improve the etching property at the time of manufacturing, and greatly exceeds the characteristics of the black mask formed by the above-mentioned prior art, and has a reflectance and its wavelength dependence over the entire visible region. Can be reduced.

A color filter according to the present invention includes such a black mask and a colored resin disposed in a plurality of openings of the black mask. This color filter separates the light transmitted through the colored resin because the black mask separates the colored resin disposed in the opening. Since the reflectance of the light irradiated on the black mask through the transparent substrate and the wavelength dependence of the reflectance are small, the ratio of the reflected light to the light transmitted through the colored resin can be reduced, and the light transmitted through the colored resin can be reduced. Can be improved.

A liquid crystal display according to the present invention is sandwiched between a first substrate having the color filter, a second substrate having a plurality of electrodes, and the first and second substrates, and applies a predetermined potential to the electrodes. Accordingly, a liquid crystal layer capable of changing the alignment is provided for each region facing the plurality of openings of the black mask. In this liquid crystal display, by applying a predetermined potential to the electrodes, the orientation can be changed for each region of the liquid crystal layer facing the plurality of openings of the black mask, so that the amount of light input to the liquid crystal layer Can be controlled for each opening of the black mask. In the opening of the black mask,
Since the colored resin is disposed, it is possible to emit light of a wavelength component corresponding to the colored resin for each of the regions. Since the color filter of the liquid crystal display can improve the visibility of light transmitted through the colored resin, a clear image can be displayed on the liquid crystal display.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a black mask according to an embodiment of the present invention will be described using a color filter 1 having a black mask. The same elements will be denoted by the same reference symbols, without redundant description.

FIG. 1 is a perspective view showing the color filter 1. The color filter 1 includes a transparent glass substrate 2, a black mask BM (black matrix) including a first antireflection film 3, a second antireflection film 4, and a light shielding film 5 sequentially deposited on the transparent glass substrate 2, Black mask B
An overcoat layer 6 formed on M and a transparent electrode 7 formed on the overcoat layer 6 are provided. further,
On the rear surface side of the transparent glass substrate 2, a polarizing plate 8 is attached.

The black mask BM according to the present embodiment
Are formed sequentially on the transparent substrate 2 and are made of the first and second antireflection films 3, 3 made of the same type of metal compound having different compositions from each other.
And a light-shielding film 5 formed on the second antireflection film 4 and containing a metal different from the metal contained in the first and second antireflection films 3 and 4. At least one of them contains chromium (Cr).

FIG. 6 is a table showing materials that can be used for each film. The suffixes X, Y, Z, A, B and C are the metal elements (Cr, Mo, W, Ni or G
The ratio of the number of atoms to e) is shown.

First antireflection film 3 and second antireflection film 4
Are oxides, nitrides,
Including carbides, oxynitrides, oxycarbides, nitrided carbides or oxynitride carbides, the metals being chromium (Cr), molybdenum (Mo), tungsten (W), nickel (Ni)
Alternatively, at least one kind of metal such as germanium (Ge) can be used. Further, the first antireflection film 3 and the second
As a material of the antireflection film 4, a mixture or a mixed crystal thereof can be used.

The first antireflection film 3 and the second antireflection film 4 have a thickness of 5 to 200 nm in order to reduce reflected light.
Is preferable, and from the viewpoint of reducing the reflected light and its wavelength dependence, the thickness is preferably 20 to 60 nm.

The material of the light-shielding film 5 may be any metal that shields visible light and is different from the metal used for the first antireflection film 3 and the second antireflection film 4. Cr, Mo, W, Ni
Alternatively, a material containing a metal such as Ge can be used. The thickness of the light-shielding film 5 is not particularly limited as long as it blocks visible light.
It is preferably from 0 to 500 nm, more preferably from 50 to 15 nm.
0 nm.

Since the first and second anti-reflection films 3 and 4 are made of the same kind of metal compound having different compositions, the refractive index and the extinction coefficient are set so as to prevent reflection, and the wavelength dependence of the reflectance is determined. While reducing the etching rate. Conventionally, when the light-shielding film and the first and second anti-reflection films contain Cr, which is the same metal, the etching rates of the respective films cannot be made uniform. Since the second antireflection films 3 and 4 contain a metal different from the metal contained in the first and second antireflection films 3 and 4, the etching rate can be made equal to that of the first and second antireflection films 3 and 4.

Further, the first and second anti-reflection films 3 and 4
Both are made of a tungsten compound, preferably an oxide, nitride, carbide, oxynitride, oxycarbide, nitride carbide or oxynitride carbide of tungsten, and the light-shielding film 5 is preferably made of chromium metal.

In particular, the constituent materials of the first anti-reflection film 3 / second anti-reflection film 4 / light-shielding film 5 are WO _{X NY} C _Z / WO _A N _B C _C
In the case of / Cr, the etching rate can be made close to obtain a precise pattern. That is, when the etching rate of Cr is 1, the etching rate of WONC forming the first and second antireflection films 3 and 4 and the etching rate of Cr forming the light shielding film 5 are all 1 or less. Further, the wavelength dependence of the reflectance can be reduced by setting the atomic ratio of each film such that the refractive index and the extinction coefficient prevent reflection according to the principle of the antireflection film.

As described above, the black mask is made of an oxide, nitride, carbide, oxynitride of at least one same metal selected from the group consisting of chromium, molybdenum, tungsten, nickel and germanium. First and second antireflection films 3, which are made of a material, oxycarbide, nitride carbide, or oxynitride carbide, and have different compositions.
4, chromium, molybdenum, tungsten, nickel,
And at least one selected from the group consisting of
The light shielding film 5 made of a kind of metal is transparent so that the metals contained in the antireflection films 3, 4 and the light shielding film 5 are different from each other and at least one of these films 3, 4, 5 contains chromium. It is sequentially laminated on the substrate 2. The black mask according to the present embodiment can improve the etching property at the time of manufacturing, greatly exceeds the characteristics of the black mask formed by the above-described conventional technique, and reduces the reflectance and its wavelength dependence over the entire visible region. Can be reduced.

FIG. 2 shows the color filter 1 shown in FIG.
It is XX arrow sectional drawing of. The black mask BM has a plurality of openings, and the three adjacent openings are filled with resins of different colors as optical filters. That is, the colored resin R is a resin colored red, is a resin containing a dye such as a red pigment and cured, and the colored resin G is a resin colored green. And a resin containing a dye such as a green pigment in the photoresist and cured.
Is a resin colored blue, which is cured by adding a dye such as a blue pigment to a photoresist. In the color filter 1, since the black mask BM separates the colored resins R, G, and B arranged in the openings, light transmitted through the colored resins R, G, and B is separated. Since the reflectance of the light irradiated to the black mask BM through the transparent substrate 2 and the wavelength dependence of the reflectance are sufficiently reduced, the ratio of the reflected light to the light transmitted through the color resins R, G, and B is reduced. And the visibility of the light transmitted through the color resins R, G, B can be improved.

Next, a method of manufacturing the color filter 1 according to the above embodiment will be described. In order to manufacture the present color filter 1, first, a transparent glass substrate 2 transparent to visible light is prepared, and a first antireflection film 3, a second antireflection film 4, Light shielding films 5 are sequentially deposited.

The first antireflection film 3 is formed by using a reactive sputtering method. That is, after disposing the transparent substrate 2 in a chamber (not shown), a metal or alloy is disposed as a target at a position facing the transparent substrate 2. Next, after the pressure in the chamber is reduced to the first pressure P1 or less, an argon gas as an inert gas (rare gas) is introduced into the chamber as necessary, and further, a target metal (C
r, Mo, W, Ni or Ge), a reaction gas (at least one of oxygen gas, nitrogen gas and carbon dioxide gas or a combination thereof) is introduced into the chamber, and the pressure in the chamber is increased. At the second pressure P ₂ . Further, while maintaining the temperature of the substrate 2 at the first temperature T ₁ while measuring the temperature of the transparent substrate 2, the first sputtering power W ₁ is applied to the atmosphere in the chamber to generate plasma and generate the target substrate. To form a first anti-reflection film 3 on the transparent substrate 2 by a reaction between the sputtered metal atoms or molecules and the reaction gas introduced into the chamber.

Here, the first pressure P ₁ is 1.5 Pa or less, more preferably 0.1 Pa or less. Second
The pressure P ₂ of is a 0.1Pa～2.0Pa, preferably 0.1Pa～1.0Pa. In addition, the first temperature T ₁ is room temperature (about 20 ° C.) to 500 ° C., preferably room temperature to 350 ° C., and more preferably room temperature to 15 ° C.
0 ° C. The first sputtering power W ₁ to be introduced during the formation of the first anti-reflection film 3, 0.5 W / cm ² or more and
20W / cm ² or less but is preferably 1W / cm ² or more ~10W / cm ² or less. There is no particular limitation on the spattering speed and time at this time, but the time to obtain the target film thickness is, for example, 10 seconds to 1 hour, and preferably 30 seconds to 20 minutes.

After the formation of the first anti-reflection film 3, the second anti-reflection film 4 is formed without removing the substrate 2 from the chamber.
The antireflection film 3 is formed using the same method.

After the second antireflection film 4 is formed, the light shielding film 5
After the pressure in the chamber was evacuated gas in the chamber until the following pressure P ₅ in the fifth, the argon gas into the chamber, introducing until the pressure in the chamber a pressure P ₆ in the sixth. Next, while maintaining the temperature of the substrate 2 at the third temperature T ₃ , the third sputtering power W ₃ is applied to the atmosphere in the chamber to generate plasma and irradiate the target substrate with the plasma.
Metal of target substrate (Cr, Mo, W, Ni or G
e, except that the first anti-reflection film 3 and the metal used when forming the second anti-reflection film 4 are sputtered, and the sputtered metal atoms or molecules are deposited on the second anti-reflection film 4. Then, the light shielding film 5 is formed.

Here, the fifth pressure P ₅ is 1.5 Pa or less, more preferably 0.1 Pa or less. Sixth
Pressure P ₆ in is a 0.1Pa～2.0Pa, preferably 0.1Pa～1.0Pa. Note that the third temperature T ₃ is room temperature (about 20 ° C.) to 500 ° C., preferably room temperature to 350 ° C., and more preferably room temperature to 15 ° C.
0 ° C. Further, the third sputtering power W ₃ applied at the time of forming the light shielding film 5 is 0.5 W / cm ² or more and 20 W / c.
m ² or less, but preferably 1 W / cm ² or more and 10
W / cm ² or less. The spattering speed at this time,
Although there is no particular limitation on the time, the time for obtaining the target film thickness is, for example, 10 seconds or more and 1 hour or less, and 20 seconds or more and 30
Within minutes is preferred. The light-shielding film 5 may be formed by using a CVD method or a vapor deposition method in addition to the above-described sputtering method.

Next, a positive photoresist is applied to the light shielding film 5.
After applying on the exposed surface of the photoresist, pre-baking, irradiating the photoresist with a pattern having a plurality of openings, sensitizing the photoresist, and developing by dissolving the photosensitive area of the photoresist using an organic solvent. By performing post-baking, a photoresist layer having a plurality of openings is formed on the light shielding film 5. Depending on the combination of metal compounds, film peeling may occur, but this can be improved by changing the film forming conditions of each film and the application conditions of the positive photoresist.

Further, by using the photoresist layer as a mask, a predetermined etching solution is brought into contact with the light-shielding film 5, the second antireflection film 4, and the first antireflection film 3 immediately below the opening of the photoresist layer, and these contact regions are formed. After the etching is completed, the photoresist layer is removed from the light shielding film 5 using an organic solvent to form a black mask BM having a plurality of openings. The above _{WO X N Y C Z / WO} A N B C C
In the production of a black mask having a / Cr structure, it is preferable to use, as an etchant, an etchant containing ceric ammonium nitrate as a main component. In this case, the light shielding film 5, the second antireflection film 4, the first It is possible to simultaneously etch the anti-reflection film 3.

Next, a negative type photoresist that is colored red by containing a red pigment is supplied onto the black mask BM from a dispenser disposed above the substrate 2, and all of the black mask BM is removed. Fill the opening.

Thereafter, the substrate 2 coated with the red photoresist is pre-baked to form a red photoresist layer having a uniform thickness. Prior to the pre-bake, the substrate 2 was adjusted so that the thickness of the red photoresist layer was uniform.
May be rotated with its thickness direction as a rotation axis.

Next, a red photoresist is applied only on the opening regions adjacent to each other in the row direction and the column direction of the openings arranged in the matrix of the black mask BM and in the diagonal direction. After exposing so as to remain, and removing the red photoresist in the non-photosensitive area using an organic solvent, baking is performed to form a red resin R in a predetermined opening of the black mask BM.

Further, instead of the red photoresist,
Using a green-colored photoresist and a blue-colored photoresist, a green resin G and a blue resin are formed in predetermined openings of the black mask BM by using the same method as the step of forming the red resin R. Form B. Each of the colored resins R, G, and B is disposed every three in the row direction and the column direction of the opening of the black mask BM, and is arranged so as to be adjacent to the diagonal direction.

Next, an overcoat layer 6 is deposited on the colored resins R, G and B so that the surface becomes uniform, and a transparent electrode 7 is deposited on the overcoat layer 6 and finally a transparent electrode is deposited. A polarizing plate 8 is attached to the back side of the substrate 2 to complete the color filter 1 shown in FIG.

Next, a liquid crystal display using the color filter 1 will be described.

FIG. 3 is a perspective view showing the liquid crystal display 100. FIG. 4 is a sectional view of the liquid crystal display 100 shown in FIG. The present liquid crystal display 100 includes a color filter 1, a TFT (thin film transistor) substrate 20 attached to the transparent electrode 7 of the color filter 1, and a backlight 26 fixed at a position sandwiching the TFT substrate 20 with the color filter 1. Prepare.

The TFT substrate 20 has an outer frame 21 and an outer frame 2 made of a light-shielding resin surrounding the outer peripheral portion of the surface of the color filter 1.
Liquid crystal layer 2 composed of nematic liquid crystal filled in 1
2. a plurality of pixel electrodes 23 provided for each region corresponding to the black mask BM opening of the liquid crystal layer 22;
Includes a transparent glass substrate 24 formed thereon and a polarizing plate 25 formed on an exposed surface of the transparent glass substrate 24.

The polarizing directions of the polarizing plates or polarizing films 8 and 25 are orthogonal to each other and are made of an organic material such as polyimide. The plurality of pixel electrodes 23 are respectively connected to a plurality of thin film transistors formed on the glass substrate 24 of the TFT substrate 20, and when a specific potential is applied to the specific pixel electrode 23, the specific pixel electrode 23 and the transparent electrode 7, a predetermined voltage is applied to the liquid crystal layer 22, and the orientation of a region corresponding to the specific pixel electrode 23 of the liquid crystal layer 22 changes by an electric field formed according to the voltage.

White light LT emitted from the backlight 26
1 is a polarizing plate or a polarizing film 2
5 and enter the liquid crystal layer 22. The incident polarized light is divided for each pixel electrode 23 and
The polarization direction changes in accordance with the amount of orientation of. The light divided for each pixel electrode 23 is the color resin R of the color filter 1,
G light and B light are respectively incident and transmitted. Since the polarizing plate or the polarizing film 8 is provided on the emission surface side of the color filter 1, the amount of light transmitted through the polarizing plate or the polarizing film 8 changes according to the amount of alignment of the liquid crystal layer 22. Since the amount of orientation of the liquid crystal layer 22 is proportional to the potential applied to the pixel electrode 23, the amount of emitted light LT2 can be controlled by controlling the potential applied to the pixel electrode 23.

As described above, the color filter 1 according to the above-described embodiment includes the black mask BM
And a transparent substrate 2 on which a black mask BM is formed, and colored resins R, G, and B disposed in a plurality of openings of the black mask BM. In the color filter 1, the black mask BM separates the colored resins R, G, and B arranged in the openings, and thus separates the light transmitted through the colored resins R, G, and B. Since the reflectance of the light irradiated on the black mask BM via the transparent substrate 2 and the wavelength dependence of the reflectance are small, the light LT2 transmitted through the colored resins R, G, and B
, And the visibility of light transmitted through the colored resins R, G, and B can be improved.

The liquid crystal display 100 according to the above-described embodiment has a structure in which the color filter 1, the liquid crystal layer 22 provided at a position facing the color filter 1, and the liquid crystal layer 22 are applied by applying a predetermined potential. A plurality of electrodes 2 provided at positions where the orientation of the liquid crystal layer can be changed for each region facing the plurality of openings of the black mask BM
3 is provided. In the liquid crystal display 100, by applying a predetermined potential to the electrode 23, the alignment can be changed in each region of the liquid crystal layer 22 facing the plurality of openings of the black mask BM. The amount of the input light LT1 is changed to the black mask BM.
Can be controlled for each opening. Black mask BM
Since the colored resins R, G, and B are disposed in the opening of the above, light of a wavelength component corresponding to the colored resins R, G, and B can be emitted for each of the regions. The color filter 1 of the liquid crystal display 100 can improve the visibility of light transmitted through the colored resins R, G, and B, so that a clear image can be displayed on the liquid crystal display 100.

[0044]

EXAMPLES A black mask BM according to the above embodiment and a black mask as a comparative example were manufactured, and the reflectance and the wavelength dependence of the reflectance were measured.

In the black mask BM of the above embodiment, the first antireflection film 3 / second antireflection film 4 / light shielding film 5
There was prepared using the following method having a _{WO X N Y C Z / WO} A N B C C / Cr structure. First, the glass substrate 2
Is mounted in a chamber of a sputtering apparatus, and the inside of the chamber is evacuated to 1.0 × 10 ⁻⁴ Pa, and then a mixed gas of nitrogen gas and carbon dioxide gas is supplied into the chamber to a pressure of 0.4 Pa in the chamber. Introduced. In addition, the flow rate percentage ratio of nitrogen gas and carbon dioxide gas, N ₂ : CO ₂
Is 1: 2. Further, the sputtering power is set to 8 W / cm.
^Then , reactive sputtering is performed using tungsten metal as a target to form a film containing tungsten oxide, tungsten nitride, tungsten carbide, tungsten oxynitride, tungsten oxycarbide, tungsten nitride carbide, and / or tungsten oxynitride carbide. A first antireflection film 3 of 55 nm was formed on the substrate 2.

Next, when the pressure in the chamber is 1.0 × 10 ^−4.
After evacuating the atmosphere in the chamber until Pa, a mixed gas of argon gas, nitrogen gas and carbon dioxide gas,
It was introduced into the chamber until the pressure in the chamber reached 0.4 Pa. Ar: N ₂ : CO ₂ ratio of argon gas, nitrogen gas and carbon dioxide gas is 10: 5: 4.
It is. Thereafter, the sputtering power is set to 4 W / cm ² , and reactive sputtering is performed with a tungsten metal as a target, and tungsten oxide, tungsten nitride, tungsten carbide, tungsten oxynitride, tungsten oxycarbide, tungsten oxycarbide, or A second antireflection film 4 having a thickness of 38 nm and containing / and tungsten oxynitride carbide was formed on the first antireflection film 3.

Next, the pressure in the chamber is 1.0 × 10 ^−4.
After the atmosphere in the chamber was evacuated to Pa, argon gas was introduced into the chamber until the pressure in the chamber reached 0.1 Pa. After that, the sputter power is reduced to 5
W / cm ² , sputtering is performed using chromium metal as a target, and a film thickness of chromium metal of 100 n
m light-shielding film 5 was formed on the second antireflection film 4. In addition,
The temperature of the substrate 2 during the formation of the films 3 to 5 is all room temperature. Finally, the films 3 to 5 were wet-etched as described above to produce a black mask BM. In this etching step, ceric ammonium nitrate was used as an etching solution.

The black mask B according to the above embodiment is
In M, the etching rates of the first antireflection film 3, the second antireflection film 4, and the light-shielding film 5 are all 1 or less when the etching rate of metal chromium is 1, so that When a black mask pattern is formed using the above etching solution, a fine and good edge shape can be obtained.

(Comparative Example) A black mask B according to a comparative example
M was produced by the following method. First, the glass substrate 2
Is mounted in a chamber of a sputtering apparatus, and the inside of the chamber is evacuated to 1.0 × 10 ⁻⁴ Pa. Then, a mixed gas of argon gas, nitrogen gas and carbon dioxide gas is introduced into the chamber at a pressure of 0. It was introduced until the pressure became 4 Pa. The ratio of the flow rates of argon gas, nitrogen gas and carbon dioxide gas, Ar: N ₂ : CO ₂ is 2: 1: 1. Further, the sputtering power is set to 2 W / cm ² ,
A first anti-reflection film having a thickness of 60 nm containing chromium oxide, chromium nitride, chromium carbide, chromium oxynitride, chromium oxycarbide, chromium oxynitride or chromium oxynitride by performing reactive sputtering with chromium metal as a target 3 was formed directly on the substrate 2.

Next, when the pressure in the chamber is 1.0 × 10 ^−4.
After evacuating to a pressure of Pa, a mixed gas of argon gas, nitrogen gas and carbon dioxide gas was pumped to a pressure of 0.
It was introduced until the pressure became 4 Pa. The flow rate ratios of argon gas, nitrogen gas and carbon dioxide gas, Ar: N
_2: CO ₂ is 10: 5: 1. Further, the sputtering power is set to 2 W / cm ² , and reactive sputtering is performed using chromium metal as a target, and chromium oxide, chromium nitride, chromium carbide, chromium oxynitride, chromium oxycarbide, chromium oxynitride or chromium oxynitride is used. A 40 nm-thick second antireflection film 4 containing carbide was formed on the first antireflection film 3.

Next, when the pressure in the chamber is 1.0 × 10 ^−4.
After the atmosphere in the chamber was evacuated to Pa, argon gas was introduced into the chamber until the pressure in the chamber reached 0.1 Pa. After that, the sputter power is reduced to 5
W / cm ² , sputtering is performed using chromium metal as a target, and a film thickness of chromium metal of 100 n
m light-shielding film 5 was formed on the second antireflection film 4. In addition,
The temperature of the substrate 2 during the formation of the films 3 to 5 is all room temperature. Finally, the films 3 to 5 were wet-etched as described above to produce a black mask BM. In this etching step, ceric ammonium nitrate was used as an etching solution.

The black mask B according to the comparative example
In M, the etching rates of the first anti-reflection film 3, the second anti-reflection film 4, and the light-shielding film 5 are 0.5 or less, 5 or more and 1
Therefore, when a black mask pattern is formed using an etching solution for a chromium film, chipping occurs in the pattern.

(Evaluation Method and Results) The transparent substrate 2 on which the black masks BM according to the above-described Examples and Comparative Examples were formed was prepared, and incident light was irradiated from the transparent substrate 2 side. The reflectance was measured. The reflectance was measured from the glass substrate 2 side using a Minolta CM-2002 spectrophotometer.

FIG. 5 is a graph showing the relationship between the wavelength (nm) of the incident light measured in this way and the reflectance (%). The black mask BM according to the above-described embodiment is
When formed above, the wavelength dependence of the reflectance is
It is lower than the wavelength dependence of the reflectance of the comparative example over the visible region of 00 to 700 nm. In addition, the black mask of the example did not cause chipping in the pattern as compared with the black mask pattern of the comparative example, and could obtain a fine and favorable edge shape.

The black mask B according to the above embodiment was used.
For M, after applying a red resist thereon, exposure,
After development, red pixels are formed, blue and green pixels are formed, and an ITO electrode is formed thereon.
A liquid crystal display manufactured by performing a series of operations such as preparation of an alignment film, rubbing, scattering of a spacer, bonding of a counter electrode substrate having a rubbed alignment film on its surface, injection of liquid crystal, sealing, and bonding of a polarizing film. Are characterized by low reflection and superior display performance such as contrast as compared with conventional liquid crystal displays.

[0056]

According to the present invention, there is provided a black mask which greatly exceeds the characteristics of the black mask formed by the above-mentioned conventional technique, has a small wavelength dependence of the reflectance over the entire visible region, and has a good etching property. A color filter and a liquid crystal display capable of obtaining a clear image can be provided.

[Brief description of the drawings]

FIG. 1 is a perspective view of a color filter.

FIG. 2 is a cross-sectional view of the color filter shown in FIG.

FIG. 3 is a perspective view of a liquid crystal display.

FIG. 4 is a sectional view of the liquid crystal display shown in FIG.

FIG. 5 is a graph showing the relationship between the wavelength (nm) of incident light and the reflectance (%).

FIG. 6 is a table showing constituent materials of each film.

[Explanation of symbols]

3 ... first antireflection film, 4 ... second antireflection film, 5 ... light shielding film, BM ... black mask, 1 ... color filter, 1
00 ... Liquid crystal display.

Claims (4)

[Claims] 1. An oxide, nitride, carbide, oxynitride, oxycarbide, oxycarbide, or oxide of at least one same metal selected from the group consisting of chromium, molybdenum, tungsten, nickel, and germanium. A first and a second antireflection film made of nitrided carbide and having different compositions, chromium, molybdenum, tungsten, nickel,
And at least one selected from the group consisting of
Black formed by sequentially laminating a light-shielding film made of a kind of metal on a transparent substrate such that the metal contained in the anti-reflection film and the light-shielding film are different from each other and at least one of the films contains chromium. mask. 2. The black mask according to claim 1, wherein the first and second antireflection films are both made of a tungsten compound, and the light shielding film is made of chromium. 3. A color filter, comprising: the black mask according to claim 1; and a colored resin disposed in a plurality of openings of the black mask. 4. A first substrate provided with the color filter according to claim 3, a second substrate provided with a plurality of electrodes, and sandwiched between the first and second substrates, and applying a predetermined potential to the electrodes. A liquid crystal layer capable of changing the orientation of each of the regions facing the plurality of openings of the black mask.