JPH11140627A - Thin film for black matrix, and target for formation of film for black matrix - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin film for black matrix, excellent both in optical properties and corrosion resisntace and capable of replacing chromium, and a target for film formation for black matrix. SOLUTION: The thin film for black matrix has a composition consisting of, by weight, 0.5-60% Cu, <=5% B, and the balance essentially Ni. It is preferable to regulate the contents of Cu and B to 10-40% and >=0.0005%, and it is further desirable to regulate the content of B to 0.002-0.5%. Moreover, the above-mentioned thin film for black matrix can be obtained by using a target having the above composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a black matrix thin film and a black matrix deposition target which are light-shielding films used for display devices such as liquid crystal and plasma displays.

[0002]

2. Description of the Related Art In liquid crystal and plasma displays, etc.,
A color filter is used as a member that enables color display by transmitting light from a light source through red, blue, and green color materials. In this color filter, a light-shielding film is formed on a glass substrate or the like for the purpose of improving contrast and preventing color mixture of color materials. This light-shielding film is generally called a black matrix. The most important characteristic of the black matrix is an optical characteristic. The optical characteristics are to sufficiently shield unnecessary light from the light source, and to reduce the reflectance because the reflected light from the outside reduces the contrast of the displayed image if the reflectance is high on the display side. Points are mainly required.

The mainstream of this black matrix is to form a film by a sputtering method and pattern it by a photolithography method.
Further, as described in JP-A-8-220326, metal chromium, chromium oxide, molybdenum, carbon, and the like are used for the black matrix. It is considered suitable.

After the formation of the black matrix, a color filter is manufactured by the following steps, for example. First, a coloring material is formed on a glass substrate having a patterned black matrix. In this step, a colored resin is spin-coated on a glass substrate on which a black matrix is formed, and a positive resist is spin-coated thereon. In this state, exposure is performed through a mask, the positive resist is patterned by development, and etching is performed using an alkaline aqueous solution or the like to pattern the colored resin. Thereafter, the positive resist is peeled off by washing with an acidic aqueous solution and warm water and an organic solution. In the case of a color filter, it is necessary to form three types of color material films of red, green, and blue, so the above process is repeated three times. Furthermore, apply a protective film, and finally,
A color filter is completed by forming an O transparent electrode film.

The above manufacturing method is a photolithography method, and one of various color filter manufacturing methods has been proposed. However, in many manufacturing methods, since a black matrix is formed by etching, the black matrix is required to have an etching property with respect to a specific etching solution. On the other hand, when the color material film is formed, the black matrix is exposed to an alkali, an acidic solution, or the like, so that the black matrix is required to have some corrosion resistance in manufacturing.

[0006]

The chromium film conventionally used has a low reflectance and is hard to transmit light, and has very good optical characteristics as a black matrix. Chromium also has excellent corrosion resistance to corrosive solutions used when forming the above-mentioned color material films. However, it has been pointed out that chromium is not preferable in terms of environmental problems because hexavalent chromium is generated when the black matrix is etched.
In view of such a problem, formation of a black matrix using molybdenum or a resin instead of chromium has been studied. However, it has not yet sufficiently provided optical characteristics, corrosion resistance, and processing accuracy. An object of the present invention is to provide a black matrix thin film having excellent optical properties and corrosion resistance that can replace chromium, and a film-forming target therefor.

[0007]

The present inventor has made various studies in view of the above problems. As a result, Ni-Cu-B
It has been found that a black matrix, which has the same optical properties as chromium and corrosion resistance to a specific corrosive liquid, can be obtained with an unprecedented alloy-based thin film.

That is, the black matrix thin film of the present invention is a black matrix thin film comprising 0.5 to 60 wt% of Cu, 5 wt% or less of B, and the balance substantially consisting of Ni. More preferably, Cu is 10 to 40% by weight, and B0.0
005 wt% or more, and more desirably, 0.002 to 0.
The range is 5 wt%.

Further, the above-mentioned thin film for a black matrix can be obtained with a target composed of 0.5 to 60 wt% of Cu, 5 wt% or less of B, and the balance substantially composed of Ni. More preferably, Cu is 10 to 40% by weight, and B0.0
005 wt% or more, and more desirably, 0.002 to 0.
The range is 5 wt%.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, an important feature of the present invention is that the inclusion of Cu in Ni reduces the reflectance and the optical density of a Ni--Cu alloy containing boron (B). Is found to be able to improve corrosion resistance without impairing optical properties by containing 5 wt% or less. As a specific composition, a new alloy system in which nickel (Ni) contains 0.5 to 60 wt% of copper (Cu) and 5 wt% or less of boron (B) is proposed. Since the present invention combines Ni, Cu, and B, there is an advantage that harmful substances such as Cr are not generated.

In the present invention, Ni is a basic element for obtaining basic optical characteristics as a black matrix. Ni secures basic corrosion resistance by forming a passivation film. In the present invention, the aforementioned N
Based on i, Cu is essentially contained. Cu reduces the high reflectivity of pure Ni, improves the optical characteristics as a black matrix,
It is an element that improves corrosion resistance by being dissolved in Ni. If the content of Cu exceeds 60 wt%, the corrosion resistance is conversely deteriorated. Therefore, in the present invention, the content is specified to be 60 wt% or less. If the Cu content is less than 0.5 wt%,
Since the effect of improving the optical characteristics is small and the effect of improving the corrosion resistance is also small, the content is specified as 0.5 wt% or more. A more preferred range is 10 to 40 wt%.

Although the basic optical characteristics and corrosion resistance of the black matrix can be ensured by the composite of Ni—Cu, according to the study of the present inventors, the corrosion resistance has not been sufficient yet. Therefore, the inventor further selected boron as the third element. Boron is Ni as described above.
It is an element that improves corrosion resistance without deteriorating the basic optical properties due to the combination of Cu and Cu.

When boron is contained in an amount of 5 wt% or less, improvement in corrosion resistance is recognized. The mechanism by which the corrosion resistance is improved by boron is considered as follows. Boron tends to segregate at the grain boundaries and lattice defects, segregates at the grain boundaries and lattice defects where the corrosion resistance of the Ni-Cu alloy is weak, and strengthens the Ni-Ni bonds in the weakly bonded parts, thereby increasing the corrosion resistance. To improve.

[0014] However, if the boron content exceeds 5 wt%, the corrosion resistance is reduced. This is because boron is excessively concentrated, causing distortion, and lowering the corrosion resistance of the grain boundaries.
The preferred amount of B for improving the corrosion resistance is 0.0005 wt.
% Or more, more preferably 0.002 to 0.5 wt%
% Range.

The optical characteristics required for the black matrix thin film of the present invention can be evaluated by the reflectance and the optical density. The reflectance is evaluated, for example, by making light of a specific wavelength incident on the thin film at a specific angle and measuring the reflected light. The optical density is a value indicating the amount of attenuation of transmitted light,
It can be represented by an optical density D = -log (I / I0). I is the intensity of the transmitted light, and I0 is the intensity of the incident light. That is, the higher the numerical value of the optical density, the more the light is blocked. The higher the reflectance, the higher the optical density, but the higher the reflectance, the lower the image contrast. Therefore, it is an advantageous material for the black matrix that the reflectance is as low as possible and the optical density is high.

The above-described black matrix thin film can be manufactured by, for example, a method such as sputtering, ion plating, and plating. In particular, application of a sputtering method using a target has an advantage that a thin film having a thickness of the order of submicrons can be obtained by a dry method. According to the studies made by the present inventors, it has been confirmed that a thin film substantially matching the target composition can be obtained by using a target having a composition corresponding to the above-described film composition as a sputtering target. That is, when the thin film for a black matrix of the present invention is to be obtained, a sputtering target that matches the film composition can be used. The target may be either an ingot material or a powder metallurgy material, but is preferably an alloy target in which Ni and Cu are dissolved in order to suppress variation in components. In particular, for a black matrix, a molten material that is advantageous in increasing the size because the target size is large and that is easily reduced in cost is preferable.

[0017]

Embodiments of the present invention will be described below. First, a black matrix film-forming target having the composition shown in Table 1 was manufactured by the following steps. Vacuum melting-hot working: heating temperature 1000 ℃, finishing thickness 3
0 [mm]-Cold rolling: Finished thickness 8 [mm]-Annealing 800 ° C
× 1 hour—Processing: Finished thickness 5 [mm] Using the obtained target, a DC magnetron sputtering apparatus was used to form a thin film having a thickness of about 100 nm on a Corning # 7059 glass substrate. Table 2 shows the composition of the obtained film. Table 3 shows the optical characteristics, and Table 4 shows the evaluation results of the corrosion resistance.

[0018]

[Table 1]

[0019]

[Table 2]

[0020]

[Table 3]

[0021]

[Table 4]

Here, the optical characteristics were measured at a wavelength of 600 nm. Reflectance was measured at an incident angle of 5 degrees. Also,
The optical density was evaluated by making the film perpendicularly incident on the film and measuring the transmitted light. As a method for evaluating corrosion resistance, a 10 wt% aqueous solution of calcium hydroxide was used as an alkaline solution, and a 10 wt% aqueous solution of sulfuric acid was used as an acidic solution, and immersed in each aqueous solution at normal temperature for 10 minutes to obtain an optical density before and after immersion. The change was evaluated. This is because the optical density depends on the film thickness and the material, and the change in the optical density before and after the corrosion resistance test changes due to the change in the thickness of the thin film or the chemical deterioration of the very surface layer. is there.

As can be seen by comparing Tables 1 and 2, it can be seen that a thin film having almost the same composition as the target was obtained. As can be seen from Table 3, the reflectivity and the optical density of Ni-Cu-B alloys (Nos.
Cu alloy (No. 9), Cr (No. 10), Mo (N
o. All of 11) have usable characteristics. However, the Ni-Cu-B alloy, which has a low Cu content, is No. 3; 1 and Mo (No. 11) have slightly higher reflectance. As can be seen from Table 4, the corrosion resistance varies greatly depending on the chemical composition. Nos. 1, 2, 3, 4, 5, and 6 of the product of the present invention
Shows corrosion resistance close to Cr used conventionally. In particular, No. in the preferred chemical composition range in the present invention
2, 3, and 4 have the same alkali resistance as Cr, and have almost the same acid resistance as Cr.

On the other hand, in the case of No. 3 out of the chemical composition range of the present invention. No. 7 and No. 8 Ni-Cu-B alloys and No. 7 9 Ni-
The Cu alloy has the same level of alkali resistance as that of the product of the present invention, but has an acid resistance of 0.1 or more, which is a level that cannot be used as a black matrix. In addition, No. In the case of Mo of No. 11, peeling occurred in both the alkali resistance and the acid resistance, indicating that the corrosion resistance was inferior to that of the present invention.

[0025]

By using the Ni-Cu-B black matrix of the present invention in place of chromium conventionally used as a black matrix, hexavalent chromium is not generated in the thin film etching process and the like. It is possible to produce liquid crystal color filters having the same corrosion resistance and optical characteristics as before. This is extremely effective in solving the environmental problems that have been concerned in recent years.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01J 11/02 H01J 11/02 Z 17/16 17/16

Claims (2)

[Claims] 1. A black matrix thin film comprising 0.5 to 60% by weight of Cu, 5% by weight or less of B, and the balance substantially consisting of Ni. 2. A black matrix film-forming target comprising 0.5 to 60% by weight of Cu, 5% by weight or less of B and the balance substantially consisting of Ni.