JP2003172921A - Counter substrate for liquid crystal display panel and liquid crystal display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the generation of a pinhole in a light shielding film formed on a counter substrate, causing light contamination to a switching element such as a TFT, in a liquid crystal display panel. <P>SOLUTION: The generation of the pinhole in the light shielding film 20 is suppressed by adding an element suppressing the generation and the progress of migration of a metal thin film which constitutes a high reflection thin film 21 into the high reflection film 21 which constitutes the light shielding film 20 provided on a light transmissive substrate 10 in a matrix shape, in the counter substrate 100 used for the liquid crystal display panel. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display panel (hereinafter referred to as a liquid crystal display panel) used as a light valve in a liquid crystal projector or the like, and more specifically, it is formed on a counter substrate of the liquid crystal display panel. The present invention relates to a light-shielding film.

[0002]

2. Description of the Related Art In a liquid crystal display panel used as a light valve in a liquid crystal projector or the like, generally, a strong liquid crystal panel is provided from the side of a counter substrate which is arranged to face a drive substrate (TFT array substrate) with a liquid crystal phase which is an electro-optical material interposed therebetween. The projected light is incident.

Then, this strong projection light is applied to the a-Si (amorphous silicon) film of the TFT or p on the driving substrate.
When incident on a region for channel formation composed of a -Si (polysilicon) film, a photocurrent is generated in this region by a photoelectric conversion effect, which deteriorates the transistor characteristics of the TFT. Therefore, in order to suppress this phenomenon, it is common to form a plurality of light-shielding films called a black matrix provided in a matrix shape on the counter substrate at a position facing each TFT.

As a light-shielding film provided in a matrix in this way, in a normal liquid crystal display device, Cr is used.
A metal material such as (chrome) or a material such as resin black in which carbon is dispersed in a photoresist is used, and in addition to the above-described light-shielding effect on the a-Si film and the p-Si film,
It also has the function of improving the contrast and preventing color mixture of color materials in the color filter.

However, when Cr or resin black is used as a light-shielding film provided in a matrix in a liquid crystal display panel used as the light valve, its own light reflectance is low, so that strong projection is achieved. It is not preferable because it absorbs light and the temperature of the liquid crystal display panel itself becomes high. Therefore, as the light-shielding film provided in a matrix on the counter substrate of the liquid crystal display panel, a high-reflectance film including a thin film of a metal having a high reflectivity such as Al or Ag is generally used. Further, in Patent Document 1, it is disclosed that a high reflectance film is provided on a glass substrate as a light-shielding film provided in a matrix, and a low reflectance film made of black resin or Cr oxide is provided thereon. It will be done. According to the invention, the projection light incident from the side of the glass substrate on which the light-shielding film is not formed, which is provided in a matrix, is reflected by the film of high reflectance to prevent the temperature of the liquid crystal display panel from rising. On the other hand, it is disclosed that stray light generated in the liquid crystal cell is absorbed by a film having a low reflectance to prevent malfunction of the liquid crystal display panel.

[Patent Document 1] Japanese Unexamined Patent Publication No. 9-212139 (No. 3-
(Page 5, Figure 1)

[0006]

However, the above-mentioned conventional technique has the following problems. That is, with the passage of time when the projection light is irradiated, pinholes are formed in the light-shielding film provided in the matrix, and the projection light that has passed through the pinholes is incident on the TFT on the opposing drive substrate. However, the liquid crystal display panel malfunctions.

The present invention has been made in view of the above-mentioned problems, and it is possible to suppress the formation of pinholes in the light-shielding film provided in a matrix on the counter substrate and to prevent malfunction of the liquid crystal display panel. Provided is a counter substrate for a liquid crystal display panel having high property.

[0008]

As described above, as the light-shielding film, a metal thin film is generally used especially on the light incident side of the counter substrate. In order to solve the above problems, the present inventors have examined the process of forming pinholes generated in a light-shielding film provided in a matrix. As a result, as the irradiation time of the projection light elapses, film stress or heat applied to the metal thin film irradiated with the projection light in the light shielding film causes migration in the metal thin film and progresses. And the occurrence and progress of this migration
It was thought that this led to the occurrence of pinholes. Therefore, by adding an element having an effect of suppressing the occurrence or progress of migration to the metal thin film forming the light-shielding film provided in a matrix, it is possible to suppress the occurrence of pinholes, and the present invention is achieved. It has been completed.

That is, the present invention has the following configuration. (Structure 1) A plurality of pixel electrodes, a drive substrate having a plurality of switching elements for individually switching-driving the plurality of pixel electrodes, a counter substrate provided opposite to the drive substrate with a predetermined gap, and The counter substrate used in a liquid crystal display panel having a liquid crystal held in a predetermined gap, the counter substrate is a substrate having a light-transmitting property, at least a region corresponding to the switching element,
A light-shielding film is formed on one or both of the regions corresponding to the drive circuit for driving the liquid crystal display panel, and the light-shielding film is composed of a metal thin film at least on the light-transmitting substrate side. The counter substrate for a liquid crystal display panel, wherein the metal thin film contains an element that suppresses the occurrence of migration.

By adopting this structure, it is possible to suppress the occurrence or progress of migration in the metal thin film due to film stress applied to the light shielding film, thermal load and the like. As a result, even if the counter substrate for a liquid crystal display panel is projected with strong projection light, the occurrence and progress of migration are suppressed, so that pinholes are not formed in the light-shielding film provided in a matrix, and the liquid crystal It is possible to prevent malfunction of the display panel.

The light-shielding film is formed on at least one of a region corresponding to the switching element and a region corresponding to a drive circuit for driving the liquid crystal display panel, or both. The drive board has a plurality of switching elements and wiring (data lines, scanning lines, etc.) formed like a grid for connecting the plurality of switching elements, but light is emitted to the plurality of switching elements and the wiring. A light-shielding film may be formed in a matrix so as not to be incident, or a light-shielding film may be formed in stripes so that light is not incident on a plurality of switching elements and wiring in one direction. The island-shaped light-shielding film may be formed so as to face the region where the switching element is formed. Alternatively, a light-shielding film may be formed in a region other than these regions corresponding to a drive circuit that drives the liquid crystal display panel. Of course, the light shielding film may be formed only in the region corresponding to the drive circuit.

(Structure 2) The element for suppressing the occurrence of migration is at least one element selected from the group consisting of Ti, Cu and Si. The substrate.

Among the elements having the effect of suppressing the occurrence of migration, Ti, Cu and Si can be easily added to the metal thin film forming the light shielding film. And T
The metal thin film to which at least one element selected from i, Cu and Si is added has sufficient mechanical properties and optical properties as a light-shielding film. As a result, an element that suppresses the occurrence of migration can be added to the metal thin film that forms the light-shielding film without deteriorating the optical characteristics and productivity of the counter substrate for liquid crystal display panel.

(Constitution 3) The amount of the element contained in the metal thin film which suppresses the occurrence of the migration is 0.1.
It is a counter substrate for a liquid crystal display panel according to the constitution 1 or 2, wherein the counter substrate is 5 at%.

By adopting this configuration, when the metal thin film forming the light-shielding film is processed into a matrix by, for example, etching, the etching characteristics and the like are not deteriorated, and when the film is projected to projection light, migration occurs. Can be suppressed from occurring and progressing. As a result, without lowering the productivity of the counter substrate for the liquid crystal display panel,
An element that suppresses the occurrence of migration can be added.

(Structure 4) The metal thin film is a high reflection film having a high reflectance so as to suppress malfunction of the liquid crystal display panel due to absorption of incident light incident on the counter substrate by the light shielding film. 4. The counter substrate for a liquid crystal display panel according to any one of configurations 1 to 3, characterized in that. In order to suppress the occurrence of malfunction of the liquid crystal display panel due to absorption of light incident on the liquid crystal display panel by the light-shielding film formed on the counter substrate, at least a metal thin film formed on the transparent substrate side. The reflectance of the high reflection film made of is preferably 70% or more, more preferably 80% or more, further preferably 9% in the visible light wavelength region.
It is 0% or more. (Structure 5) The high reflection film is made of an Al alloy and / or A
5. The counter substrate for a liquid crystal display panel according to the structure 4, wherein the counter substrate contains a g-alloy.

As the highly reflective film, Al, Al alloy, or A
When a thin film of g or Ag alloy is used and an element that suppresses the occurrence of migration is added to it, the light reflectance is high in the visible light wavelength range from 380 nm to 700 nm, and the wavelength dependence of the reflectance is high. It is possible to obtain a metal thin film which has a low reflectance and a uniform reflectance, and in which the occurrence and progress of migration are suppressed even when projected onto projection light. As a result, a counter substrate for a liquid crystal display panel having high characteristics can be easily manufactured.

(Structure 6) In the light-shielding film, a low-reflection film having a reflectance lower than that of the high-reflection film is formed on the side of the drive substrate.
The counter substrate for a liquid crystal display panel according to 1.

Stray light is generated when strong projection light passes through the inside of the liquid crystal display panel. This stray light is TF on the drive substrate.
Irradiation of T or the like causes malfunction of the liquid crystal display panel. Therefore, by adopting this structure, it is possible to prevent the stray light from reflecting the projected stray light to the TFT or the like on the drive substrate and causing the liquid crystal display panel to malfunction. It is also possible to prevent the contrast of the image from being lowered. The low reflectance of the low reflection film is preferably 30% or less, more preferably 20% or less, and further preferably 10% or less, because the lower reflectance can reduce the reflection of stray light in the liquid crystal cell.

(Structure 7) The low reflection film is made of Ti, Cr,
W, Ta, Mo, Pb, or oxides thereof, or nitrides thereof, or oxynitrides thereof, or oxides, nitrides, or oxynitrides of refractory metal silicides thereof. 7 is a counter substrate for a liquid crystal display panel according to structure 6.

The lower the reflectance of the low reflection film is, the less the reflection of stray light in the liquid crystal cell can be reduced. Therefore, Ti, Cr, W, Ta, Mo, Pb, their oxides, or these oxides It is preferable that the above-mentioned nitride, an oxynitride of these, an oxide, a nitride, an oxynitride of a refractory metal silicide of these, or a material having a black organic dye. In addition, these members (low reflection film), after forming the high reflection film which is the metal thin film,
Since it can be easily formed on the counter substrate by a sputtering method or a vapor deposition method, a counter substrate for a liquid crystal display panel having high characteristics can be easily manufactured. The light-shielding film in which Cr or Cr oxide, Cr nitride, or Cr oxynitride is used as the low-reflection film and is combined with the AlTi alloy as the metal thin film has a mutual film adhesion force between both members. strong,
This is preferable from the viewpoint that the pattern cross-sectional characteristics when the light-shielding film is etched are sharp.

(Structure 8) The counter substrate for a liquid crystal display panel according to any one of Structures 4 to 7, wherein the high-reflection film and the low-reflection film are continuous films whose compositions change continuously. Is.

With this structure, when placed in an environment where the temperature greatly changes from room temperature to high temperature or from high temperature to room temperature, the heat of the high reflection film, which is the metal thin film, and the low reflection film are reduced. It is possible to reduce stress generated due to physical properties such as difference in expansion coefficient. Further, since the high-reflection film and the low-reflection film are continuous films whose compositions change continuously, the shape stability when etching the light-shielding film in a matrix is excellent.

Furthermore, when the high reflection film and the low reflection film are continuously formed by a sputtering method, a portion where the sputtered particles of the high reflection film material and the sputtered particles of the low reflection film material overlap with each other is generated. It is also possible to adopt a forming method of sputtering. According to this forming method, the composition of the high-reflection film and the low-reflection film in the cross-sectional direction of the light-shielding film can be changed stepwise or continuously at an arbitrary ratio, and the high-reflection film and the low-reflection film can be changed. It is possible to form a light-shielding film having good durability without peeling at the interface, and also to form a light-shielding film provided in a fine pattern matrix.

(Structure 9) In the translucent substrate, a substrate on which a microlens is formed is provided on the side on which light is incident on the counter substrate, and the microlens comprises:
9. The counter substrate for a liquid crystal display panel according to any one of configurations 1 to 8, which is formed so that the light is projected onto the pixel electrode.

With this structure, the incident light incident on the counter substrate for the liquid crystal display panel passes through each microlens provided corresponding to the opening of each light-shielding film provided in a matrix, for example. The luminous flux is narrowed down when doing. As a result, most of the incident light passes through the opened positions of the light-shielding film provided in a matrix, and further passes through the drive substrate without irradiating the TFT (switching element) formed on the drive substrate. To do. Therefore, the thermal burden due to incident light and stray light on the light-shielding film provided in a matrix on the counter substrate and the TFT formed on the driving substrate is reduced, and the reliability that malfunction does not occur. A counter substrate for liquid crystal display panels with high
The utilization efficiency of projected light can be improved. As a result, in combination with the effect of the element that suppresses migration added to the light-shielding film, the liquid crystal display panel having this configuration is
It is possible to project a bright and excellent image with high reliability. According to the present invention, there is also provided a liquid crystal display panel characterized by being manufactured using the counter substrate for a liquid crystal display panel according to any one of the above configurations 1 to 9.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic sectional view of a counter substrate according to an embodiment of the present invention. First, in FIG. 1, the counter substrate 100 includes a light-transmissive substrate 10 and a light-shielding film 20.
have. A transparent conductive film may be formed so as to cover the light-shielding film 20 to serve as the counter substrate. Furthermore, the light-shielding film 2
0 is a metal thin film (hereinafter, referred to as a high reflection film) 21 on the transparent substrate 10 side, and a thin film of a member having a lower reflectance than the metal thin film on the drive substrate side (not shown) (hereinafter,
It is described as a low reflection film. ) 25 and. The light-shielding film 20 is formed on the counter substrate 100 on a surface facing a switching element for individually switching-driving pixel electrodes on a drive substrate (not shown) of the light-transmissive substrate 10 and a matrix facing the wiring connecting the switching elements. It is provided in a shape.

The transparent substrate 10 is required to be a transparent material capable of withstanding the thermal action of strong projected light.
A transparent quartz substrate, a non-alkali glass substrate and the like are preferably used. The high reflection film 21 forming the light shielding film 20 includes
An Al alloy and an Ag alloy containing a small amount of a metal such as Ni, Ag, Pt, and Al and an additive metal such as Pd are preferably used, and an element that suppresses the occurrence and progress of migration is added. In particular, when a material containing Al as a main component is used for the high-reflection thin film 21, the light reflectance is high in the wavelength range of 380 to 700 nm which is the wavelength range of visible light, and the reflectance has less wavelength dependence and is uniform. This is a preferable structure because it has a reflectance, has good adhesion to the low reflection film 25 described later, and can form a light-shielding film provided in a matrix of a fine pattern. Light-shielding film 20
The low-reflective film 25 constituting the metal includes metal, metal oxide, metal nitride, metal oxynitride, Ti, Cr, W, Ta, and M.
refractory metal silicide such as o and Pd, eg WSi
(Tungsten silicide) or MoSi (molybdenum silicide) oxide, nitride, oxynitride, or black organic dye is preferably used.

As described above, when the counter substrate 100 is projected by the projection light, pinholes are prevented from being generated in the light-shielding film 20 provided in a matrix, so that the high reflection film 21 is prevented from migration. The element that suppresses the generation and progress is added, but this element is Ti, Cu, S
At least one selected from i, Pd, etc. is preferable.
When a material containing Al as a main component is used as the material of the high reflection film 21 of the light-shielding film 20 and a material containing Cr as the main component is used as the material of the low reflection film 25, the occurrence and progress of migration is suppressed. When Ti is selected as the element, it is preferable in that the interface peeling does not occur between the high reflection film 21 and the low reflection film 25 when the light shielding film 20 is patterned to form a matrix light shielding film. .

Therefore, hereinafter, Ti is selected as an additive element for suppressing the occurrence of migration, the high reflection film 21 contains Al as a main component, and the low reflection film 25 contains Cr. Counter substrate 10
Taking 0 as an example, the effect of adding an additive element for suppressing the occurrence of migration will be described.

A as a main component used for the high reflection film 21.
The film containing 1 is in the wavelength range of visible light as described above.
The reflectance of light is high in the wavelength range from 80 nm to 700 nm, the reflectance has less wavelength dependency, and a uniform reflectance can be obtained. Further, the adhesiveness to the low reflection film 25 described later is good, and the fineness is fine. It is a preferable metal film because it can form a matrix-shaped light-shielding film having various patterns. Low reflective film 2
A Cr nitride film is used for 5. The low reflectance of the low-reflection film is preferably 30% or less, more preferably 20% or less, further preferably 10% or less, since the lower the reflectance is, the less the reflection of stray light in the liquid crystal cell can be reduced. The film has favorable optical characteristics as a low reflection film, and at the same time, when formed on the Al film,
The mutual film adhesion is strong, and the shape stability when forming the light-shielding film described later in a matrix is excellent,
It is preferable from the points such as. As a method of adding Ti to the Al film, when a film containing Al as a main component is formed on the transparent substrate 10 by a sputtering method, a desired amount of Ti is previously added in a sputtering target of Al or an Al alloy. Is preferable from the viewpoint of workability and cost.

Here, with reference to FIGS. 2 and 3, T is used as an additive element for suppressing the occurrence and progress of migration.
The effect obtained by adding i to the light-shielding film 20 will be described. FIG. 2 shows the addition of Ti added as an element for suppressing the occurrence and progress of migration in the metal thin film of the highly reflective film that constitutes the light-shielding film samples (1 to 8) on the transparent substrate in the counter substrate. And the amount of light-shielding film sample (1 to
8 is a table showing the evaluation results of the incidence rate of pinholes in 8) and the shape stability during etching of the light-shielding film. FIG. 3 is a cross-sectional view schematically showing the etching shape of the light-shielding film when evaluating the shape stability after etching the light-shielding film sample. Hereinafter, the effect of suppressing the generation of pinholes by adding an element that suppresses the occurrence and progress of migration to the metal thin film of the high-reflection film,
The shape stability of the light-shielding film during etching will be described.

First, as a substrate, an alkali-free glass substrate (NA35: manufactured by NH Techno Glass Co., Ltd.) having a thickness of 1.1 mm was prepared. Next, as a sputtering target for forming the light-shielding film, an Al target to which different concentrations of Ti were added and a Cr target were provided in close proximity to each other at a distance of 1 inch. Here, the amount of Ti added to the Al target is 0 to 0 as shown in FIG.
It corresponds to Samples 1 to 8 in 8 steps of 6.5 at%.

Using an in-line sputtering device, AlTi thin films having different Ti contents with a thickness of 1 are formed on the glass substrate.
00-800Å, preferably 200-400Å
Then, a Cr nitride thin film was formed to a thickness of 80 to 2000Å, preferably 300 to 1400Å to prepare Samples 1 to 8.
During the sputtering, the film was formed while flowing an argon gas containing nitrogen from the substrate unloading side of the in-line sputtering device. A photosensitive resin (resist) was applied to each of Samples 1 to 8 after the film formation by a spin coat method to have a predetermined thickness (for example, 5).
000Å) and further using a photomask, a matrix resist film having a width of 4 μm and a pitch of 26 μm was formed. After etching the Cr nitride thin film on each of Samples 1 to 8 on which the matrix-shaped resist film was formed using a Cr etching liquid (HY liquid: (manufactured by Wako Pure Chemical Industries)),
Further, by immersing in an alkaline aqueous solution to dissolve and remove the resist film, the AlTi alloy thin film is etched at the same time to form a matrix light-shielding film into a sample 1 for a liquid crystal display panel.
~ 8 was obtained.

Here, the shape stability of the light-shielding film formed in a matrix on the counter substrate samples 1 to 8 was evaluated by an electron microscope. This evaluation method will be described with reference to FIG. FIG. 3 is a schematic view of the light-shielding film provided in a matrix after etching, observed from an upper surface on which the light-shielding film is formed, by an electron microscope. The concave portions 26 and the convex portions 27 generated by the etching are observed. The bottom of the concave portion 26 and the convex portion 2
The distance from the top of 7 is Z. The larger the height difference Z between the irregularities, the poorer the shape stability of the light-shielding film provided in a matrix, and the malfunction of the liquid crystal display panel in the subsequent process. The unevenness of the surface is called roughness (grating), and the degree of roughness (grating) is evaluated by the distance Z between the bottom of the concave portion 26 and the top of the convex portion, and further, the degree of this roughness (grating) is evaluated. The shape stability when the light-shielding film was etched to form a black matrix was evaluated. The evaluation method is x when the roughness (grating) Z exceeds 1 μm, Δ when the roughness (grating) Z is 0.1 to 1 μm, and Δ when the roughness (grating) Z is less than 0.1 μm. It evaluated as ◯ and the evaluation result was described in FIG.

Next, the counter substrate samples 1 to 8 were placed in a convection oven and heated at 120 ° C. for 500 hours, and the presence or absence of pinholes in the light-shielding film provided in a matrix was examined with a metallographic microscope. I observed. After the heating test, if pinholes were generated on the counter substrate samples 1 to 8, the number of generated pinholes was measured, and the number was measured.
Described in. The number of pinholes generated was measured by observing a 5 mm × 5 mm area of the high reflection film surface formed on the counter substrate samples 1 to 8 with a metallurgical microscope.

As is clear from the results shown in FIG. 2, the evaluation by the shape stability during etching revealed that Samples 1 to 6 were free from creases and had an extremely good pattern shape. found. On the other hand, sample 7 is 0.5 μm
Front and rear creases were generated, and in Sample 8, it was further proved that creases exceeding 1 μm were generated, and the pattern shape was extremely poor. From the above, in order to form a light-shielding film having a good pattern shape and pattern accuracy, the Ti content in the AlTi alloy thin film is preferably 5 at% or less.

On the other hand, as is clear from the results shown in FIG. 2, the number of pinholes generated was 20 or more in the evaluation of the number of pinholes generated. It was found to be a level that causes malfunctions due to nation. In sample 2, the number of pinholes generated was 9, which was found to be a boundary level that could cause a malfunction due to optical contamination when a liquid crystal display panel was manufactured. It was found that Samples 3 to 8 had 0 to 1 pinholes and were at a level at which a malfunction due to optical contamination did not occur when a liquid crystal display panel was manufactured. From the above, in order to prevent malfunction due to optical contamination, Al
The Ti content in the thin film is preferably 0.1 at% or more. From the above results, it was found that the amount of Ti added to the Al film is preferably 0.1 to 5.0 at%, more preferably 0.25 to 2.0 at%.

Further, in the above-mentioned counter substrate, Ti is added as an additive element for suppressing the occurrence and progress of migration.
Instead of Si (1at%), Cu (0.5at%), S
i (0.5at%) + Ti (0.5at%), the high-reflection film is made of AlSi alloy, AlCu alloy, AlS, respectively.
As the iTi alloy, the number of pinholes generated and the shape stability were evaluated in the same manner as described above. As a result, AlSi alloy (S
i: 1 at%), AlSiTi alloy (Si: 0.5 at)
%, Ti: 0.5 at%), the number of pinholes generated was 0, but in the case of the AlCu alloy, the number of pinholes generated was 2. Also, in terms of shape stability,
AlSiTi alloy (Si: 0.5 at%, Ti: 0.5
at%) and AlCu alloy (Cu: 0.5 at%) were good when the roughness (roughness) Z was less than 0.1 μm.
In the case of i alloy (Si: 1 at%), a little roughness (roughness) Z
Was large and was in the range of 0.1 to 1 μm. From these results, instead of AlTi alloy, AlSi alloy, AlCu
Alloys and AlSiTi alloys are also applicable, but AlTi alloys and then AlSiTi alloys are preferred.

Here, an embodiment of a low reflection film formed on a high reflection film to which an element that suppresses migration is added, and a preferable forming method thereof will be described.
As described above, the low reflection film is made of metal, metal oxide, metal nitride, metal oxynitride, Ti, Cr, W, Ta, Mo.
And refractory metal silicides such as Pd, eg WSi
(Tungsten silicide) or MoSi (molybdenum silicide) oxide, nitride, oxynitride, or black organic dye is preferably used. When a metal, a metal oxide, a metal nitride, a metal oxynitride, a refractory metal silicide, or an organic dye is used as the low reflection film, after the high reflection film is formed on the translucent substrate, sputtering is performed on the high reflection film. It is preferable to form a uniform thin film by evaporation or vapor deposition.

When a metal oxide, metal nitride, or metal oxynitride thin film is used as the low-reflection film, oxygen and / or nitrogen is introduced into the film during the film formation of these metal compounds to obtain a desired film. A metal oxide having a composition, a metal nitride,
A method for forming a metal oxynitride, or a method for forming a desired metal oxide, a metal nitride, or a metal oxynitride by heating the film after forming a metal in an oxygen and / or nitrogen atmosphere,
Furthermore, using a target material of metal oxide, metal nitride, metal oxynitride, desired metal oxide, metal nitride,
A method of forming a metal oxynitride thin film by sputtering is preferable.

On the other hand, when the refractory metal silicide is used as the low reflection film, a desired refractory metal silicide thin film is formed by sputtering using a target material of the refractory metal silicide compound, or the refractory metal film and Si are used. The film can be formed into a high melting point metal silicide compound thin film by heating after forming the film by vapor deposition or sputtering.

In particular, when a metal, metal oxide, metal nitride, or metal oxynitride thin film is used as the low-reflection film, the light-shielding property is high and the reflectance can be low even if the film thickness is small. Furthermore, since it does not contain an alkali metal that interferes with the driving of the liquid crystal display panel, it is optimal as a light-shielding film for a liquid crystal display panel. Further, the thin film of metal oxide, metal nitride, or metal oxynitride used as the low-reflection film is formed so that the composition of the metal film continuously changes on the high-reflection film so that Adhesion is further improved. In particular, when Cr or Ni is used as a metal, chromium oxide or nickel oxide is used as a metal oxide, chromium nitride or nickel nitride is used as a metal nitride, and chromium oxynitride or nickel oxynitride is used as a metal oxynitride, an element that suppresses migration is used. It is preferable that the adhesiveness with the added high-reflection film is good and a light-shielding film provided in a matrix having a fine pattern can be formed.

When the film thickness of the high-reflection film added with the element that suppresses migration is 300 Å or more, sufficient reflectivity for projection light is exhibited, and the film thickness of the low-reflection film is 80 Å or more to prevent stray light in the liquid crystal cell. Demonstrate supplementary effects. When the total film thickness of the high-reflection film and the low-reflection film is 2000 Å or less, disconnection of the pixel electrode formed on the light-shielding film can be prevented and thermal stress applied to the light-shielding film becomes extremely large. None, it is a preferable configuration. Here, at least the optical density of the light-shielding film composed of the high-reflection film and the low-reflection film is 3 or more, preferably 4 or more.

Depending on the selection of materials for the high-reflection film and the low-reflection film, there is a problem that peeling may occur at the interface between the high-reflection film and the low-reflection film. In particular, when Al or a substance containing Al as a main component is used for the highly reflective film, A
Peeling may occur due to the oxidation of l. In that case,
It is also possible to form, between the high-reflection film and the low-reflection film, a portion in which a member having a high reflectance which constitutes the high-reflection film and a member having a low reflectance which constitutes the low-reflection film are mixed. As a method of forming such a light-shielding film, first, a high-reflection film and a low-reflection film are formed and then heat-treated at a high temperature to form a high-reflection film at the interface between the high-reflection film and the low-reflection film. A manufacturing method may be used in which the substance and the substance forming the low reflection film are thermally diffused to each other to realize a stepwise or continuous composition change.

Alternatively, the high-reflection film and the low-reflection film may be formed by forming substances that react with each other to form a compound and reacting at the interface between the high-reflection film and the low-reflection film by heating or the like. it can. For example, the low reflection film is made of Si or a Si compound, and the high reflection film is made of W, Ni, Cr, A.
It is formed of a substance that reacts with Si such as l. According to this method, when the light-shielding film is placed in a high-temperature environment and a room-temperature environment, stress generated due to physical properties such as a difference in coefficient of thermal expansion between the high-reflection film and the low-reflection film is generated. Will be reduced.

Further, when the high reflection film and the low reflection film are continuously formed on the translucent substrate by the sputtering method, the constituent substances of the high reflection film knocked out from the sputtering target of the high reflection film material. Sputtered particles composed of and sputtered particles composed of the constituent material of the low-reflection film sputtered from the sputter target of the low-reflection film material were sputtered on the translucent substrate so as to form an overlapping (mixing) portion. There is a manufacturing method. According to this manufacturing method, the constituents of the high-reflecting film and the low-reflecting film in the cross-sectional direction of the light-shielding film can be changed in composition in a stepwise or continuous manner and at an arbitrary ratio. There is no peeling at the interface with the low reflection film, and a light-shielding film with good durability is formed.
A light-shielding film provided in a matrix with a fine pattern can be formed.

Here, as a manufacturing method, on the translucent substrate, there is a portion where the sputtered particles composed of the constituent material of the high reflective film and the sputtered particles composed of the constituent material of the low reflective film are overlapped (mixed) with each other. , For example, a method of placing a target material made of a material forming a high reflection film and a target material made of a material forming a low reflection film in close proximity to each other, or increasing the distance between the target material and the substrate, A manufacturing method in which a part where the sputtered particles overlap with each other is generated is preferable. In particular, a method of forming a material for forming a high reflection film and a material for forming a low reflection film side by side on one target material is a method in which the high reflection film and the low reflection film can be formed by one target material and In the material, it is an extremely excellent manufacturing method in which the film thickness of the high reflection film and the low reflection film can be controlled by controlling the widths of the target material forming the high reflection film and the target material forming the low reflection film.

As described above, Al and N are used for the high reflection film.
A metal thin film in which an element that suppresses migration is added to a metal such as i, Ag, or Pt or an alloy in which a small amount of an additive metal such as Pd is added to these metals is used. Therefore, when chromium oxide or nickel oxide is used as the metal oxide of Cr or Ni for the low reflection film and chromium nitride or nickel nitride is used as the metal nitride, the adhesion to the above-mentioned high reflection film is good and a matrix of a fine pattern is used. A light-shielding film provided in a shape can be formed. Here, in the oxide or nitride of the low reflection film, it is preferable that the oxidation degree or the nitridation degree gradually increases from the high reflection film side toward the drive substrate side.

On the translucent substrate, an Al or Al alloy thin film, which is a highly reflective film and to which an element for suppressing migration is added, is formed by a sputtering or vapor deposition method.
On this Al or Al alloy thin film, a region in which Al and the components of the low reflection film change in composition gradually and / or continuously is formed, and a low reflection film is further formed thereon. There is also a configuration. Then, the light-shielding film obtained in this configuration is patterned by photolithography and etching using a photosensitive resin as a resist film to pattern the low-reflection film, and the photosensitive resin is removed with an alkaline aqueous solution while the high-reflection film is used. A certain Al or Al alloy thin film is etched to form a light-shielding film provided in a matrix. This method of manufacturing the light-shielding film provided in the matrix form is provided in the matrix form because the etching progresses using the low reflection film as an etching mask in the step of etching the Al or Al alloy thin film which is the high reflection film. This is preferable because the edge shape of the light-shielding film becomes sharp. In addition, it is an excellent method with many advantages, such as etching of a highly reflective film of Al or Al alloy thin film and removal of the patterned photosensitive resin can be performed at the same time.

Next, different embodiments according to the present invention will be described with reference to the drawings. FIG. 4 is a schematic cross-sectional view of a counter substrate 200 having a light-shielding film having one layer of a highly reflective film according to another embodiment of the present invention, and FIG. 5 is a schematic view of a counter substrate with a microlens substrate. FIG. Incidentally, in FIGS. 1, 4, and 5, the corresponding parts are designated by the same reference numerals. Further, similarly to the above, a transparent conductive film may be formed so as to cover the light shielding film 20 to serve as the counter substrate.

The counter substrate 200 shown in FIG. 4 has a light-shielding film having one layer of a highly reflective film, and the light-transmitting substrate 1
0, there is a light-shielding film 20, and there is a high reflection film 21 that constitutes the light-shielding film 20. In the counter substrate 200, the light-shielding film 20 that is a highly reflective film is provided in a matrix on the translucent substrate 10. In the light-shielding film 20, as described above, when strong projection light enters the liquid crystal display panel,
In order to suppress the temperature rise of the liquid crystal display panel, the reflectance of the light-shielding film 20 is preferably 70% or more, more preferably 80% or more, in the visible light wavelength region.
More preferably, it is 90% or more, and in general, a thin film of Al, Al alloy, Ag, or Ag alloy is suitably used as the high reflection film 21. In the present invention, this highly reflective film 21
An element that suppresses the occurrence and progress of the above-mentioned migration is added. As the transparent substrate 10, a transparent quartz substrate, a non-alkali glass substrate or the like is preferably used. The counter substrate 200 having this configuration is preferably used for a liquid crystal display panel in which the generation of stray light in the liquid crystal cell is small, or the TFT or the like on the drive substrate is not easily affected by stray light. .

The counter substrate 300 with a microlens substrate shown in FIG. 5 includes a light-transmissive substrate 10, a light-shielding film 20, a light-transmissive substrate 31, and a high refractive index medium 33. The light-shielding film 20 is a highly reflective film. 21 and the low reflection film 25, the transparent substrate 3
A large number of concave portions 32 having a curved bottom wall surface are provided in a matrix on the surface of the first transparent substrate 10 in contact with the concave portion 32.
And the high refractive index medium 33 form a microlens 35 to form a microlens array. In the counter substrate 300 with a microlens substrate, the light-transmissive substrate 10, the light-shielding film 20, the light-transmissive substrate 31, the high reflection film 21, and the low reflection film 25 have the same configuration as the counter substrate 100 described above. There is. A high-refractive-index medium 33 is sandwiched between the transparent substrate 10 and a transparent substrate 31 provided with a concave portion 32. The concave portion 32 and the high-refractive-index medium 33 function as a convex lens. The microlens 35 has is configured. This microlens 35 has its focal point located at the center of the opening of the light-shielding film 20 provided in a matrix.
The position, the number, and the curved surface of the bottom wall surface of the recess 32 are adjusted.

The counter substrate 30 with the microlens substrate
By using 0, the incident light entering the counter substrate for the liquid crystal display panel first passes through the transparent substrate 31 and then passes through the microlens 35, so that the luminous flux is narrowed. As a result, most of the incident light passes through the openings of the light-shielding film provided in a matrix, and further passes through the drive substrate without irradiating the TFT formed on the drive substrate. As a result, the T formed on the light-shielding film 20 and the driving substrate.
Since the thermal burden on the FT due to incident light and stray light is reduced, a highly reliable liquid crystal display panel in which malfunction does not occur in combination with the effect of the element added to the light-shielding film 20 to suppress migration. It is possible to obtain a bright and good image because it is possible to obtain a counter substrate for use and improve the light utilization efficiency.

Next, the present invention will be described in more detail with reference to examples. (Example 1) <AlTi only> An AlTi alloy thin film containing 0.5 at% of Ti was formed to a thickness of 500 Å on a 1.1 mm thick quartz glass substrate by a sputtering method. A photosensitive resin (resist) is formed on the AlTi alloy thin film by the spin coat method at 5000 Å
And a photomask was used to form a matrix resist film having a width of 4 μm and a pitch of 26 μm.
Next, using a mixed solution of phosphoric acid and nitric acid, AlT was applied to the glass substrate on which the resist film in matrix form was formed.
The i alloy was etched and then immersed in an alkaline aqueous solution to dissolve and remove the resist film. Furthermore, the substrate heating temperature 1
An ITO film was formed on the AlTi alloy pattern by sputtering under the condition of 50 ° C. to obtain a counter substrate for a liquid crystal display panel.

In the counter substrate for a liquid crystal display panel manufactured as described above, the reflectance from the glass surface is 92% (that is, the incident light side surface of the counter substrate (incident side glass substrate surface reflection + incident side AlTi alloy). Thin film surface reflection)). Also, 1
After the heat resistance test at 20 ° C. for 500 hours, it was confirmed by observation with a metallurgical microscope that no pinhole was generated in the AlTi alloy thin film.

(Example 2) <AlTi / CrO> An AlTi alloy thin film containing 0.5 at% of Ti was formed to a thickness of 300 Å by a sputtering method on a 1.1 mm thick quartz glass substrate, and further the sputtering method was used. To form a Cr oxide thin film with a thickness of 800 Å. Then, a photosensitive resin (resist) was formed on the glass substrate by a spin coating method to a thickness of 5000 Å, and a photo resist was used to form a matrix resist film having a width of 4 μm and a pitch of 26 μm. The glass substrate on which the matrix resist film is formed is dipped in a ferric chloride solution to etch the Cr oxide thin film, the Al alloy thin film is etched with a mixed solution of phosphoric acid and nitric acid, and then dipped in an alkaline aqueous solution. The resist film was removed by dissolution. Next, under the condition that the substrate heating temperature is 150 ° C., this AlTi alloy / Cr oxide
An ITO thin film was formed on the pattern by sputtering to obtain a counter substrate for a liquid crystal display panel.

The counter substrate for liquid crystal display panel manufactured as described above has a reflectance of 87% from the glass surface (that is, the incident light side surface of the counter substrate (incident side glass substrate surface reflection + incident side AlTi alloy). The thin film surface reflection)), and the reflectance from the surface on which Cr oxide was formed was 12%. Also, 120 ℃,
As a result of observation with a metallurgical microscope after the heat resistance test for 500 hours, it was confirmed that no pinholes were generated in the Al alloy thin film.

(Example 3) <AlTi / Cr continuous film> A 1.1 mm thick non-alkali glass substrate (NA35: N)
H Techno Glass Co., Ltd.)
Was deposited to a thickness of 300Å, and then a Cr thin film was deposited to a thickness of 800Å.
In addition, when the composition change was confirmed by Auger analysis, k
It was confirmed that the i alloy thin film and the Cr thin film were continuous films in which the composition was continuously changed. Here, the target used for sputtering is a target having a width of 6 inches, and a target in which AlTi (Ti: 0.5 at%) is provided in a width of 2 inches on the substrate loading side and Cr is provided in a width of 4 inches on the substrate unloading side. Was used. A photosensitive resin (resist) was applied on the glass substrate after the film formation by a spin coat method to a thickness of 5000 Å, and a photo resist was used to form a matrix resist film having a width of 4 μm and a pitch of 26 μm. The glass substrate on which the matrix-like resist film is formed is immersed in a Cr etching solution (HY solution: (manufactured by Wako Pure Chemical Industries)) to etch Cr, and then an Al alloy is further mixed with a mixed solution of phosphoric acid and nitric acid. Etching was performed, and finally, the resist film was dissolved and removed by immersing in an alkaline aqueous solution. The glass substrate on which the etching and the resist film removal have been completed is treated with AlTi under the condition that the substrate heating temperature is 150 ° C.
An ITO film was formed on the alloy / Cr pattern by sputtering to obtain a counter substrate for a liquid crystal display panel.

The counter substrate for a liquid crystal display panel manufactured as described above has a reflectance of 88% from the glass surface (that is, the incident light side surface of the counter substrate (reflection on the glass substrate surface on the incident side + AlTi alloy on the incident side). The thin film surface reflection)), and the reflectance from the surface on which Cr was formed was 36%. Also, 120 ° C, 50
After the 0-hour heat resistance test, the result of observation with a metallurgical microscope was A
It was confirmed that no pinhole was generated in the 1-alloy thin film. Furthermore, it was confirmed that the obtained pattern cross section had no step and had an extremely good cross section.

(Example 4) <AlTi / CrN continuous film> A 1.1 mm-thick non-alkali glass substrate (NA35: N)
H-Techno Glass Co., Ltd.), an AlTi alloy thin film containing Ti at 1.0 at% was formed into a film having a thickness of 100 Å, and then a Cr nitride thin film 1200 Å was formed using an in-line sputtering device. The target used for sputtering at this time was
An AlTi (Ti: 1.0 at%) target and a Cr target are provided in close proximity to each other at a distance of 1 inch.
During sputtering, the film was formed while flowing an argon gas containing nitrogen from the substrate unloading side. When the composition change was confirmed by Auger analysis, it was confirmed that AlTi alloy thin film and Cr nitride
It was confirmed that the thin film was a continuous film whose composition changed continuously. A photosensitive resin (resist) was applied on the glass substrate after the film formation by a spin coat method to a thickness of 5000 Å, and a photo resist was used to form a matrix resist film having a width of 4 μm and a pitch of 26 μm. When the glass substrate on which the matrix-like resist film is formed is etched with a Cr nitride thin film using a Cr etching solution (HY solution: (manufactured by Wako Pure Chemical Industries)), the resist film is further dissolved and removed in an alkaline aqueous solution. At the same time, the AlTi alloy thin film was etched. An ITO film was formed on the Al alloy / Cr pattern by sputtering on the glass substrate on which the etching and the removal of the resist film were completed at a substrate heating temperature of 150 ° C. to obtain a counter substrate for a liquid crystal display panel.

The counter substrate for a liquid crystal display panel manufactured as described above has a reflectance of 85% from the glass surface (that is, the incident light side surface of the counter substrate (incident side glass substrate surface reflection + incident side AlTi alloy). The thin film surface reflection)), and the reflectance from the surface on which Cr nitride was formed was 12%. Also, 120 ℃,
As a result of observation with a metallurgical microscope after the heat resistance test for 500 hours, it was confirmed that no pinholes were generated in the Al alloy thin film. Furthermore, it was confirmed that the obtained pattern cross section had no step and had an extremely good cross section.

Comparative Example 1 An Al thin film having a thickness of 100Å was formed on a non-alkali glass substrate (NA35: manufactured by NH Techno Glass Co., Ltd.) having a thickness of 1.1 mm by a sputtering method.
Further, a Cr thin film having a thickness of 12 is formed by the sputtering method.
00Å A film was formed. A photosensitive resin (resist) is applied on the glass substrate after film formation by a spin coating method to a thickness of 5000 Å, and a photomask is used to obtain a width of 4 μm.
A matrix-shaped resist film having a pitch of 26 μm was prepared. The glass substrate on which this matrix-like resist film is formed is etched with a Cr etching solution (HY solution: (manufactured by Wako Pure Chemical Industries)), and then an Al thin film is mixed with a mixed solution of phosphoric acid and nitric acid. Was etched, and finally, the resist film was dissolved and removed by immersing it in an alkaline aqueous solution. An ITO film was formed on the Al / Cr pattern by sputtering on the glass substrate after the etching and the removal of the resist film at a substrate heating temperature of 150 ° C. to obtain a counter substrate for a liquid crystal display panel.

The counter substrate for a liquid crystal display panel manufactured as described above has a reflectance of 50% from the glass surface (that is, the incident light side surface of the counter substrate (reflection on the glass substrate surface on the incident side + Al thin film on the incident side). Surface reflection)), the reflectance from the surface on which Cr was formed was 60%. Further, after a heat resistance test at 120 ° C. for 500 hours, as a result of observation with a metallographic microscope, it was confirmed that pinholes having a diameter of about 0.5 to 1.0 μm frequently occurred in the Al alloy thin film. In addition, when the pattern shape was observed with an electron microscope, it was found that knurls of more than 1 μm were generated.

(Embodiment 5) A concave portion in which the position, the number, and the curved surface of the bottom wall surface of the concave portion are adjusted in advance so as to be located at the center of the opening of the light-shielding film provided in a matrix described later, etc. A glass substrate and a cover glass substrate formed by one-way etching were prepared. A high-refractive-index resin was filled and bonded between the glass surface provided with the recess and the cover glass substrate to fabricate a microlens substrate in which a large number of microlenses were formed to form a microlens array. A light-shielding film and an ITO film provided in a matrix were formed on the cover glass substrate side of this microlens substrate by the same method as in Example 4 to fabricate a counter substrate with a microlens substrate. In the counter substrate with a microlens substrate manufactured as described above, at 120 ° C., 50
After the 0-hour heat resistance test, the result of observation with a metallurgical microscope was A
It was confirmed that no pinhole was generated in the 1-alloy thin film. Furthermore, it was confirmed that the obtained pattern cross section had no step and had an extremely good cross section.
When a liquid crystal display panel was produced using this counter substrate with a microlens substrate, it was possible to obtain a liquid crystal display panel having a bright and good screen without causing malfunction.

[0066]

As described above in detail, according to the present invention, in the light-shielding film in the liquid crystal display panel, the optical contamination to the switching element such as TFT is suppressed to a low level.
In order to provide a counter substrate for a liquid crystal display panel for manufacturing a liquid crystal display panel that prevents malfunction of switching elements and exhibits high contrast, a plurality of pixel electrodes and
A drive substrate having a plurality of switching elements for individually switching-driving the plurality of pixel electrodes, a counter substrate opposed to the drive substrate via a predetermined gap, and a liquid crystal held in the predetermined gap. The counter substrate used in a liquid crystal display panel having, wherein the counter substrate is a region having at least a region corresponding to the switching element and a region corresponding to a drive circuit for driving the liquid crystal display panel, on the substrate having translucency. A light-shielding film is formed on one or both of the above, and the light-shielding film is a counter substrate for a liquid crystal display panel in which at least the substrate side having the light-transmitting property is composed of a metal thin film, In the thin film,
The present invention invents a counter substrate for a liquid crystal display panel, which is characterized by containing an element that suppresses the occurrence of migration. As a result of the present invention, it is possible to obtain a highly reliable counter substrate for a liquid crystal display panel in which pinholes of the light-shielding film provided in a matrix are suppressed and a malfunction of the liquid crystal display panel does not occur.

[Brief description of drawings]

FIG. 1 is a sectional view of a counter substrate according to an embodiment of the present invention.

FIG. 2 is a table showing the evaluation results of the number of pinholes generated and the shape of a light-shielding film pattern provided in a matrix.

FIG. 3 is a diagram for explaining a method for evaluating the pattern shape of a light-shielding film provided in a matrix.

FIG. 4 is a cross-sectional view of a counter substrate in which a light shielding film according to another embodiment of the present invention has one layer of a high reflection film.

FIG. 5 is a cross-sectional view of a counter substrate with a microlens substrate according to another embodiment of the present invention.

[Explanation of reference numerals] 10 ... Translucent substrate, 20 ... Light-shielding film, 21 ... Highly reflective film,
25 ... Low reflective film, 35 ... Microlens, 100 ... Opposing substrate, 300 ... Opposing substrate with microlens substrate.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kenji Tanaka             2-7-5 Nakaochiai, Shinjuku-ku, Tokyo Ho             Within Ya Co., Ltd. F term (reference) 2H091 FA34Y FB08 FC01 FC02                       GA13 KA01 KA10 LA17                 2H092 JA24 JB52 MA04 MA05 MA15                       NA01 NA21 PA09

Claims (10)

[Claims] 1. A drive substrate having a plurality of pixel electrodes, a plurality of switching elements for individually switching-driving the plurality of pixel electrodes, and a counter substrate disposed opposite to the drive substrate with a predetermined gap therebetween. The counter substrate used for a liquid crystal display panel having a liquid crystal held in the predetermined gap, wherein the counter substrate is a translucent substrate, at least a region corresponding to the switching element, and the liquid crystal. A light-shielding film is formed on one or both of regions corresponding to a drive circuit for driving the display panel, and the light-shielding film is a liquid crystal in which at least the substrate side having the light-transmitting property is formed of a metal thin film. A counter substrate for a display panel, wherein the metal thin film contains an element that suppresses the occurrence of migration. Plate. 2. The counter substrate for a liquid crystal display panel according to claim 1, wherein the element that suppresses the occurrence of migration is at least one element selected from Ti, Cu, and Si. . 3. The amount of the element contained in the metal thin film which suppresses the occurrence of the migration is 0.1 to 5 at%.
The counter substrate for a liquid crystal display panel according to claim 1 or 2, wherein 4. The metal thin film is a highly reflective film having a high reflectance so as to prevent malfunction of the liquid crystal display panel due to absorption of incident light entering the counter substrate into the light shielding film. The counter substrate for a liquid crystal display panel according to any one of claims 1 to 3. 5. The counter substrate for a liquid crystal display panel according to claim 4, wherein the high reflection film contains an Al alloy and / or an Ag alloy. 6. The light shielding film according to claim 4, wherein a low reflection film having a reflectance lower than that of the high reflection film is formed on the drive substrate side. Counter substrate for liquid crystal display panel. 7. The low reflection film is formed of Ti, Cr, W, Ta,
7. An oxide, a nitride, or an oxynitride of Mo, Pb, or an oxide thereof, a nitride thereof, an oxynitride thereof, or a refractory metal silicide thereof. A counter substrate for a liquid crystal display panel as described above. 8. The high reflection film and the low reflection film are continuous films whose compositions change continuously.
7. A counter substrate for a liquid crystal display panel according to any one of 1 to 7. 9. In the translucent substrate, a substrate having a microlens is provided on a side of the counter substrate on which light is incident, and the microlens projects the light onto the pixel electrode. 9. The counter substrate for a liquid crystal display panel according to claim 1, wherein the counter substrate is formed as described above. 10. A liquid crystal display panel manufactured using the counter substrate for a liquid crystal display panel according to claim 1.