JP2001102325A - Silver alloy thin film and sputtering target for film formation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an Ag alloy thin film for flat panel display and the like with lower electrical resistance than Al, high chemical resistance and heat resistance, satisfactory adherence to substrate and the like and superior patterning property, and to provide a sputtering material with high film formation rate and easy handling of spent material at a low cost. SOLUTION: An Ag sputtering target is a metallic thin film used for manufacturing electrode film of flat panel display, reflection film and light shielding film. Essentially, the film is made of an Ag/Ru/Cu alloy with electrical resistivity which is not higher than 13 μΩm, average reflection property at 90 nm thickness film surface side and visible radiation range, and optical density not lower than 4.0. Weight percentage of three elements is 75<=Ag<100 wt.%, 0<Ru<25 wt.%, and 0<Cu<25 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an Ag alloy thin film and a sputtering target for forming the same. More specifically, the present invention relates to an Ag alloy thin film useful for manufacturing an electrode film and a light-shielding film for a flat panel display, and a reflective film, and a sputtering target for forming the same.

[0002]

2. Description of the Related Art Conventionally, flat panel displays (hereinafter referred to as "display panels") have been used as display panels for various information devices.
FPD) is widely used. Liquid crystal displays (LCD), plasma display panels (PD)
P) is used. <1> Transmissive TFT-LCD FIG. 7 of the accompanying drawings shows a transmissive TFT, which is a conventional LCD.
FIG. 2 illustrates a cross-sectional view of an FT-LCD.

As shown in FIG. 7, a transmission type TFT-LC
D is a color filter (CF) substrate including a black matrix (BM) (4) having a function as a light-shielding film and pixel layers (5) of three primary colors, and a liquid crystal layer (9) interposed therebetween. And a transparent electrode (10).
And the TFT (11) which is a pixel switch element is opposed to B
It is regularly formed corresponding to M and each pixel region.

FIG. 3A of the accompanying drawings illustrates a cross-sectional view of a top gate type a-Si TFT on the TFT substrate side. As shown in FIG. 3A, when the TFT on the TFT array substrate is of a top gate type, the source electrode (21), the drain electrode (22), and the semiconductor layer (a).
-Si, 23 and 24), a gate insulating film (25), and a gate electrode (26), the main part of which is composed of a gate wiring, a source electrode (21) and a drain electrode (22). Are connected to data wirings to exchange electrical signals, and the two wirings are three-dimensionally orthogonal.
In order to increase the screen size and increase the definition of various LCDs, high-speed transmission of electric signals is required. Therefore, it is necessary to reduce the resistance of these wiring materials.

The materials used for the wiring film are Mo, C
r, Ta, Ti, MoTa, Al, Cu and the like. Of these, the four elements Mo, Cr, Ta, and Ti have relatively high electrical resistivity of 50 to 200 μΩcm, and
The alloy film has been put into practical use because of its excellent patterning property by dry etching, but its electric resistivity is about 35%.
The low resistivity of μΩcm is still insufficient.

Further, Al has a low resistance of about 18 μΩcm, has good patterning properties, and is inexpensive, and has been put to practical use. At present, it is mainly used as a wiring film material. However, Al is poor in chemical resistance and heat resistance. For example, the surface becomes cloudy when left indoors, or the film is slightly swelled in an annealing process at about 300 ° C. or more performed after patterning, resulting in migration such as uneven surface. Is easy to occur.

Therefore, the Al wiring film is covered with a cap metal such as a Cr film, protected by an anodic oxide film or the like, or Mo / Al / Mo or Ti / Al / T
Although the chemical resistance and the heat resistance are increased by interposing a paral metal such as i, there are problems such as an increase in the number of film layers and the number of manufacturing steps.

Further, Cu is about 14 μΩcm, which is the lowest resistance in the above material group, but has poor adhesion to the substrate, so that pinholes, film peeling and the like are likely to occur, and patterning is not easy. is there.

As described above, TFT-LC
The electrode and wiring film for D have an electric resistance value of 13 μΩcm or less, which is lower than that of Al, have high chemical resistance and heat resistance, have good adhesion to a substrate or the like, and have excellent patterning properties. It is desired that the number of layers of the film and the number of processing steps are not so large. <2> Transmissive TFT-LCD (light-shielding layer on array method) In the case of a transmissive TFT-LCD that has been widely used in the past, the BM, which is a light-shielding film, is disposed on the CF substrate facing the TFT array substrate. This enhances the contrast of the display screen, sharpens the image, prevents transmission of external light to the TFT array substrate side, and prevents erroneous switching. However, the aperture ratio may be reduced due to extra light shielding due to the overlapping accuracy of the opposing substrates.

Therefore, in recent years, in order to solve this problem, the BM is often provided on the TFT array substrate side in order to improve the aperture ratio, which is called a light-shielding layer on-array method. . Further, a gate electrode and a gate wiring made of a material such as Mo, Ta, and Al are formed simultaneously on the glass substrate, and the light-shielding film is formed. The light-shielding layer is connected to the gate electrode and the wiring to serve as a storage capacitor electrode. BM electrodes that also have a role have been developed. The light-shielding layer is formed on the TFT element (electrode), the gate wiring, the source wiring, and the end of the pixel electrode with a protective film interposed therebetween. At this time, for example, a barrier metal layer such as Mo or Ti
The upper layer has a two-layer structure composed of a low-resistance metal layer such as Al, and the uppermost layer has a structure covered with an insulating film.

As described above, the light-shielding film is a BM electrode film, which is also an electrode. In addition to the electrical characteristics such as low resistance described in the above <1>, chemical resistance, heat resistance, etc. However, it is particularly required to be excellent in light-shielding properties that can provide a high optical density even if the thickness is small. <3> Reflective TFT-LCD FIG. 5 of the accompanying drawings is a cross-sectional view which also serves to explain the screen display of the reflective TFT-LCD.

As shown in FIG. 5, a reflective TFT-LC
D displays a screen using reflection of external light. In other words, since there is no backlight such as a transmissive LCD, there are advantages such as low power consumption, light weight, and the ability to be used indoors and outdoors. ing. In a reflection type TFT-LCD, for example, a reflection plate made of an Al thin film or the like is provided on an inner surface of a TFT array substrate, and a process such as a film formation or plating method is particularly performed on a drain region formed in a pixel electrode shape. The reflective electrode (4
Sometimes it is 2).

Since the Al thin film has high reflectivity and is inexpensive, it is often used as a reflector or a reflective electrode. However, the reflected light is absorbed by a liquid crystal layer or the like to lower the reflectivity, or the heat of the absorption causes a decrease in the screen. Since sharpness may be impaired, a reflective film having a higher reflectivity has recently been required.

Therefore, an Ag film or an Ag alloy thin film has been proposed. However, the Ag-based film has poor chemical resistance and poor adhesion to a substrate such as glass, and easily discolors in air or causes film peeling. In some cases, there remains a problem in patterning.

As means for solving the above-mentioned problems, development of a reflection plate or a reflection electrode having a higher reflectivity than an Al thin film and having good adhesion and patterning properties so that a barrier metal (underlying film) is unnecessary. It has been demanded. <4> PDP Reflecting Electrode FIG. 6 of the attached drawings illustrates a cross-sectional view of a plasma display panel (PDP).

As shown in FIG. 6, the PDP is composed of a transparent electrode (52) such as ITO and a bus electrode (53) such as Cr / Cu / Cr on a front glass substrate (51). Display electrode, a transparent dielectric layer (54), and MgO
A protective layer (55) is sequentially formed, and the front glass substrate (5
The rear glass substrate is disposed with the partition rib (56) interposed therebetween. On the other hand, on a rear glass substrate (62), a trigger electrode (not shown) provided in parallel with the display electrode, an insulating layer, an address electrode (61) provided three-dimensionally orthogonal to the display electrode, and a dielectric material. Layers (60) are sequentially formed. A phosphor layer (58) and a discharge gas space (59) are provided on the inner surface of the partition rib (56), and a reflection film (57) may be provided so as to be sandwiched between the partition rib and the phosphor layer.
The phosphor layer is excited by ultraviolet rays of the discharge generated in the discharge gas space (59) to generate visible light.

The reflective film has the effect of efficiently extracting visible light generated by the discharge to the display screen side to increase the luminance. In recent years, the use of a low-resistance metal material such as Al has caused the address electrode ( There is also a reflective electrode film having the role of 61).

In a PDP having a specific structure emphasizing mass productivity, the address electrode may be made thicker in view of prevention of oxidation during sealing and mass productivity. An Ag paste in which a BiO component is dispersed in a binder and a solvent is also used.

As for the address electrode film (61) and the pass electrode film (53) for PDP as described above, there is a demand for a material for producing a film having lower resistance and higher reflectivity. <5> Recycling of Resources, Magnetic Characteristics of Sputtering Target and Film Deposition Rate Generally, in film deposition using a magnetron sputtering device, plasma is locally focused by a magnet disposed on the back side of a metal target. Then, the target is sputter-etched and uneven erosion proceeds. The deepest part of this heterogeneous erosion determines the efficiency of target utilization. The utilization efficiency of this target is generally about 20 to 30%, and the remaining 70%.
About% is discarded in consideration of the recovery and recycling costs.

On the other hand, when a sputtering target having a relatively strong magnetic property is used, the lines of magnetic force are converged inside the target, the magnetron becomes unstable, the deposition rate is reduced, and the film quality distribution can be easily made uniform. Although various measures such as providing a gap in the target to promote magnetic field leakage and raising the target temperature to lower the magnetic permeability have been taken, there are problems such as the equipment system becoming complicated. there were.

Furthermore, when patterning is performed with an etching solution for various films, a film-forming material is eluted in a waste solution. However, considering the cost of recovering the film-forming material, it is presently discarded. In view of the above, there has been a demand for a sputtering material which has a high film forming rate, that is, is as small or non-magnetic as possible, and which can easily collect used materials and is inexpensive.

[0022]

Means for Solving the Problems The present invention solves the above-mentioned problems by providing an electrode film for a flat panel display, a metal thin film used for manufacturing a reflective film and a light-shielding film, Substantially Ag-Ru-Cu
And a thin film composed of a three-element alloy of
The electric resistivity is 13 μΩcm or less, and the film thickness is 90 nm.
Has a film surface side average reflectance of 93% or more in the visible light region,
A, characterized in that the optical density is at least 4.0 at the same time.
A g alloy thin film is provided.

Further, the invention of this application is characterized in that, secondly, the Ag alloy thin film is a gate electrode film or a wiring film of a TFT-LCD, and -A black matrix electrode film of an LCD; fourth, a reflective TFT-LC
D is a reflection plate, a pixel electrode film serving as a liquid crystal driving electrode, or a reflection pixel electrode film having a role of both a reflection plate and a pixel electrode. Fifth, an Ag alloy thin film is used as an address electrode film for a plasma display panel. , As well as a bus electrode.

Further, the invention of this application is, sixthly, a sputtering target for introducing an Ar gas into a vacuum apparatus and depositing the Ag alloy thin film on a substrate by sputtering. The composition of the target is substantially composed of a three-element alloy of Ag—Ru—Cu, and the composition ratio is 75 ≦ Ag by weight fraction.
<100 wt%, 0 <Ru <25 wt%, 0 <Cu <2
Also provided is an Ag alloy sputtering target characterized by being 5 wt%.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION The Ag alloy thin film for FPD of the present invention substantially consists of a three-element silver alloy of Ag-Ru-Cu. Note that the definition of "substantial" here is
Except for the raw material of the sputtering target material and inevitable impurities derived from other manufacturing processes, it means that the metal element contains only the three elements of Ag, Ru, and Cu.

Disadvantages of a pure silver metal thin film are, as is generally known, a weak adhesion to a transparent substrate or a pixel material, easily causing peeling or bin holes, poor corrosion resistance, moisture in the air when left indoors, Due to the presence of oxygen and sulfur compounds, silver diffuses and agglomerates to promote deterioration, and furthermore, it is inferior in physical strength such as easy wear and abrasion.

For example, a binary silver alloy thin film of Ag-Mx (Mx: a noble metal element) in which a noble metal such as Pt is added to Ag is inferior in abrasion resistance and abrasion resistance. In the case of a binary silver alloy thin film of Ag-My (My: reforming promoting element) to which Cu or the like is added as a reforming accelerator, heat resistance,
Although physical strength such as abrasion resistance is improved, the transparent substrate (1) is used in any case because of low resistance and insufficient corrosion resistance.
Then, an underlying film such as a silicon oxide film or a resin film is provided, and then an Ag or Ag alloy thin film is formed.

Therefore, in the present invention, in order to obtain an Ag alloy thin film having excellent adhesion and corrosion resistance so that the barrier metal is unnecessary, a noble metal Mx having a property that it is hardly oxidized to Ag and hardly eroded by acid or alkali is used. By the alloying of Ag, diffusion and agglomeration of Ag are suppressed, adhesion and corrosion resistance are remarkably improved, and migration such as minute surface irregularities and swelling (hillock) of the film can be suppressed even when heat treatment is performed. Focusing on the fact that the resistance can be reduced and that the addition of metal My to Ag improves the wear resistance and scratch resistance, a three-element silver alloy thin film of Ag-Mx-My, especially Ag-
This led to the development of a Ru—Cu silver alloy thin film.

As the noble metal Mx to be added, in addition to Ru,
One selected from Au, Pd, Pt, Rh, and Re, and the reforming promoting element My, besides Cu, Ti, Z
Ag-Mx consisting of one selected from r, Zn, and Al
The -My silver alloy thin film can also be suitably used as an electrode film for FPD, a reflective film, a reflective electrode film, or the like.

However, in the present invention, if the total content of Ru and Cu exceeds 25 wt%, the corrosion resistance is deteriorated such that the surface layer of the alloy becomes cloudy.
Ag <100 wt%, 0 <Ru <25 wt%, 0 <Cu
<25 wt%.

The Ag-Ru-Cu alloy sputtering target of the present invention can be applied to a conventionally known sintering method in powder metallurgy. Can be manufactured. In addition, the production of Ag alloy-based targets, particularly containing less irreversible impurities, is less than the production of other general alloy targets, and currently provides a high-purity Ag alloy sputtering target of less than 0.1 wt%. it can.

Of course, in the present invention, the film structure and the number of layers of the Ag alloy thin film for FPD are not particularly limited, and the optical density of a single-layer metal film even if the film thickness is as thin as 90 nm is not limited. It has a sufficient light-shielding function with 4.0 or more,
Further, compared to an Al (alloy) thin film, the absorption of external light is small, so that a display image is not deteriorated due to an increase in liquid crystal temperature. Therefore, it is suitably used as a black matrix.

FIG. 1 of the accompanying drawings shows an Ag alloy thin film of the present invention formed on a transparent substrate. As shown in FIG. 1A, as the transparent substrate (1), a non-alkali glass, an alkali-containing glass on which an alkali elution preventing layer is formed, or the like is applied, as shown in FIG. 1B. As described above, an inorganic or resinous transparent insulating film or conductive film may be formed on a transparent substrate.

As a film forming means, a sputtering method of a batch type or an in-line type can be appropriately adopted. Usually, a ternary Ag alloy target is preferably used as a film forming material, for example, a sputtering target. However, a mixture target or a multiple (3) Ag, Ru, or Cu target can also be used. The introduced gas mainly uses Ar gas.

The present invention is to provide a novel Ag alloy thin film and a sputtering target for forming the same, which have never been described before, with the above-described structure. Explanation will be given according to an example. Of course, the present invention is not limited by the following examples.

[0036]

EXAMPLE 1 A transparent and clean non-alkali glass substrate having a thickness of 0.7 mm was set in a film forming apparatus, the inside of the apparatus was kept constant at about 80 ° C., and after exhausting sufficiently, Ar gas was discharged. Pressure 0.28Pa
Power density 3.5 w / cm ² in the gas atmosphere introduced in
, A ternary silver alloy target of Ag-Ru-Cu
By sputtering for 30 seconds, a silver alloy thin film (2) was formed on the glass substrate (1) as shown in FIG.

When the composition ratio of this thin film was determined by an energy dispersive X-ray analyzer (EDX) manufactured by JEOL Ltd., Ag, Ru, Cu = 93.4: 4.4: 2.2 wt.
%Met.

The electrical resistivity of the thin film is 12.2 μΩcm, which is lower than that of about 18.0 μΩcm of the Al (alloy) film, and the optical density is 4.24 despite its thinness of 90 nm. In addition, the average reflectance in the visible light region having a wavelength of 400 to 700 nm is 94.2% as in the spectral reflectance characteristic shown in FIG. 2, which is 7.6% as compared with 86.6% of the Al alloy. Was also expensive. The film formation rate is 1 w / unit power density.
It is about 0.2 nm / sec per cm ² , and the
It is about 3.1 times faster than 065 nm / sec.

The reflectivity was measured using a microspectroscopic light OSP-SO200 manufactured by Olympus Optical Co., Ltd., using an aluminum thin film as a reference. The average reflectivity was defined as, for example, every 1 nm wavelength. Are obtained by summing the reflectivities and dividing by the number of measurement points 301.

From this, it was found that the Ag alloy thin film of the present invention is superior to an Al (alloy) film in electrical resistivity, reflectivity, light-shielding properties, and film forming speed at least equally. <a> Practicality test including chemical resistance, heat resistance, etc. The Ag-Ru-Cu ternary silver alloy thin film obtained in Example 1 is generally made of Ag in the production process of FPD.
Tests were conducted on practicality, including chemical resistance and heat resistance, which are considered as defects of the film. The test items and methods are as shown in Table 1 below.

[0041]

[Table 1]

The samples after the test obtained according to Table 1 were observed for film peeling, presence or absence of pinholes, and discoloration of the film.
Before and after the test, the optical density change rate of the film,
When the change in the film surface reflectance and the like were comprehensively evaluated, the evaluation results for all the test items did not cause any problem. From this, it has been found that there is sufficient practicality in manufacturing an electrode for FPD, a reflective film, a reflective electrode film, a light shielding film, and the like.

However, in the ternary silver alloy black matrix of the present invention, if the silver content ratio is less than 75% by weight, the deterioration of corrosion resistance becomes remarkable, and the black matrix cannot be formed, so that 75 ≦ Ag <10
0 wt%, 0 <Ru <25 wt%, 0 <Cu <25 wt
% Is desirable. <b> Evaluation of patterning property by photolithography technique The Ag-Ru-Cu ternary silver alloy thin film substrate obtained in Example 1 was evaluated for patterning property by photolithography technique.

Ce (NH ₄ ) ₂ (NO ₃ ) ₆ : 70% H
ClO ₄ : H ₂ O = 165 g: 42 ml: 1000 ml
A black matrix was formed using an etching solution prepared at a rate of 30 ° C. and having a liquid temperature of 30 ° C. The etched cross-sectional shape of the pattern should have excellent etching properties because there was almost no sandwiching of thin films, the pattern width was uniform, and no corrosion such as film peeling or film turbidity was observed. There was found.

The above-mentioned etching solution has almost the same components as those of the chromium etching solution which is already known in the field of manufacturing information devices such as liquid crystal panels and is frequently used when a black matrix is formed by patterning a chromium metal thin film. Therefore, it is an important feature that existing patterning manufacturing equipment and methods can be diverted as they are.

As for the etching solution, Ag metal can be easily recovered by adding nitric acid or ammonia water as required, reducing Ag ions using a reducing solution such as formalin, and referring to a silver mirror reaction for precipitation. Was.

On the other hand, collecting and reusing a used Ag alloy target that leaves about 70% of a portion not used for erosion is more economical than mining and refining a new Ag-containing ore. Yes, it can be easily melted and regenerated as a target. Therefore, resources can be used with great care by recycling without incurring waste disposal costs. Example 2 A transparent and clean non-alkali glass substrate having a thickness of 0.7 mm was set in a film forming apparatus, the inside of the apparatus was kept constant at about 80 ° C., and after sufficiently exhausting, Ar gas was supplied at a pressure of 0.28 Pa.
Power density 3.5 w / cm ² in the gas atmosphere introduced in
, A ternary silver alloy target of Ag-Ru-Cu
Sputtering was performed for 2 seconds to form a film having a thickness of about 140 nm as shown in FIG.

This film was patterned by photolithography using the cerium ammonium nitrate + perchloric acid type etching solution shown in FIG.
The source / drain electrode portions shown in FIG. Thereafter, a semiconductor layer and a gate insulating film were formed over the electrode portion by a plasma CVD method using an Ar gas, a doping gas, a silane gas, or the like. A gate electrode film having a thickness of about 140 nm was formed thereon by sputtering using an Ag alloy target similarly to the formation of the electrode portion. The semiconductor layer / gate insulating film / gate electrode film were dry- and wet-etched together to produce a top-gate type a-Si TFT as shown in FIG. The electrical resistivity of the electrode film in each part was as low as 12.5 μΩcm. Example 3 Similarly to the sputtering film formation using the sputtering target of the present invention shown in Example 1 and Example 2, the bottom game type a-Si TFT illustrated in FIG. And Ag on data wiring and gate wiring
A light-shielding film made of a -Ru-Cu alloy was formed, and a BM electrode was manufactured by the etching performed in Example 1. The film thickness was 90 nm, and the optical density was 4.2, which was a sufficiently excellent light-shielding property. Example 4 As in Example 3, Ag-Ru-
A light-shielding film made of a Cu alloy was formed, and a reflective electrode film having a thickness of 90 nm was formed on the pixel electrode portion by the etching performed in Example 1. At this time, the reflectance is 55
At 0 nm, it is 94.3%, and as shown in FIG. 2, the reflectance in the entire visible light region is Al (alloy) for comparison.
It was clearly higher than the thin film. Fifth Embodiment As in the fourth embodiment, the address electrode film (61) and the pass electrode film (5), which are members for a PDP as shown in FIG.
3) was produced. These were also confirmed to have low resistance and excellent adhesion.

[0049]

As described in detail above, the present invention provides an Ag alloy thin film for FPD having excellent adhesion and corrosion resistance (resistance to moisture, sulfur compounds, acidic substances, etc.).

As a result, a film can be formed directly on a transparent substrate, no barrier metal (underlying film) is particularly required, and in some cases, a protective film and a heat-resistant reinforcing film (cap metal) are not required. Is lower than that of an Al (alloy) thin film, has a sufficient optical density while maintaining a certain optical density, and has a higher reflectance than an Al film in the entire visible light region. It can be used with little change in the patterning method and apparatus of the Ag film by the wet method, and it does not contain harmful metals such as Cr. Of course, the metal is recovered from the etching solution and used target and recycled. Is possible, and magnetron sputtering is easy because the main component susceptibility of the sputtering target is relatively small. Once again, for example, Al (alloy) is faster that such a large technical feature compared when approximately three times or more and when I was the target, it is possible to use the electrode film, a reflective film for a flat panel display, a reflection electrode film or the like.

[Brief description of the drawings]

FIG. 1 is a schematic view of an Ag alloy thin film of the present invention formed on a transparent substrate. (A) A film is formed directly on a transparent glass substrate. (B) An underlayer (barrier metal) is formed on a transparent glass substrate.

FIG. 2 shows a spectral reflectance characteristic of a film surface.
U is an Ag alloy thin film of the present invention, and V is an Al alloy thin film for comparison.

FIG. 3 is a top gate type aS on the TFT array substrate side.
i shows a TFT. (A) It shows the sectional view. (B) A plan view of one pixel, showing an example of the arrangement of pixel electrodes and respective wirings.

FIG. 4 shows a bottom gate type aS on the TFT array substrate side.
i shows a TFT. (A) Cross-sectional model diagram. (B) An example in which a TFT element is covered with a light-shielding film is shown. (C) An outline of a black matrix showing a state in which a gate wiring and a data wiring are covered with a light shielding film, and a pixel electrode in an opening.

FIG. 5 is a cross-sectional view also illustrating a screen display of the reflective TFT-LCD.

FIG. 6 is a cross-sectional view illustrating a plasma display panel (PDP).

FIG. 7 is a cross-sectional view illustrating a transmissive TFT-LCD that is a conventional LCD.

[Explanation of symbols]

 Reference Signs List 1 transparent substrate (color filter substrate side) 2 Ag alloy thin film 3 base film (barrier metal) 4 spectral reflectance curve of Ag alloy thin film 5 color filter layer (R, G, B pixel portion) 6 protective film (overcoat) 7 transparent Electrode 8 Liquid crystal 9 Liquid crystal layer 10 Transparent electrode 11 Pixel switch element (thin film transistor / TFT) 12 Sealing part 13 Transparent substrate (TFT array substrate side) 14 Deflection plate (Color filter substrate side / Visual side) 15 Deflection plate (TFT frame substrate) Side) 20 top gate type a-Si TFT 21 source electrode 22 drain electrode 23 semiconductor layer (n-type a-Si) 24 semiconductor layer (i-type a-Si) 25 gate insulating film 26 gate electrode 27 data wiring 28 gate wiring 29 Pixel electrode 30 Bottom gate type a-Si TFT 31 Protective layer 32 Light shielding film (black matrix 41) Insulating layer 42 Reflective electrode film 50 Plasma display panel (PDP) 51 Front glass substrate 52 Transparent electrode 53 Pass electrode 54 Transparent dielectric layer 55 MgO protective film 56 Partition rib 57 Reflective film 58 Phosphor layer 59 Discharge gas space 60 Dielectric Body layer 61 Gate electrode 62 Back glass substrate

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) G02F 1/1365 H01J 11/02 B 5F110 H01J 11/02 G02F 1/136 500 H01L 29/786 H01L 29/78 617J 618B ( 72) Inventor Koichi Koyama 1414 Shimonomoto, Higashimatsuyama-shi, Saitama Pref.Toshima Works, Ltd. (72) Inventor Tadakatsu Suzuki Kawakita Shimobukuro Higashi 17 Wakayanagi-cho, Kurihara-gun, Miyagi Pref. Yanagimachi Takeyari character Hanamizue 1-1 Inside Kuramoto Seisakusho Co., Ltd. (72) Inventor Hiromitsu Satake 1-1 Wakayanagimachi Takeyari character Hanamizumae, Kurihara-gun, Miyagi Prefecture Kuramoto Seisakusho F-term (reference) 2H042 AA02 AA26 DA04 DC02 2H091 FA14Y FA34Y FB08 FC01 FC29 GA02 GA13 LA30 MA10 2H092 HA02 HA05 JA37 JB21 JB51 JB54 MA05 MA35 PA12 RA10 4M104 AA10 BB08 BB38 CC01 DD40 GG20 HH09 HH16 5C040 GC05 GC18 GC19 JA07 KA02 KB17 KB29 MA10 GG02 MA17 GG

Claims (6)

[Claims] 1. A metal thin film used for manufacturing an electrode film, a reflection film, and a light-shielding film for a flat panel display, which is a thin film substantially made of a three-element alloy of Ag-Ru-Cu. Means that the electrical resistivity is 13μΩc
m or less, the film surface side average reflectance at a film thickness of 90 nm is 93% or more in the visible light region, and the optical density is 4.0 at the same time.
An Ag alloy thin film characterized by the above. 2. The method according to claim 1, wherein the Ag alloy thin film is a TFT.
-Ag alloy thin film which is a gate electrode film or a wiring film of LCD. 3. An Ag alloy thin film according to claim 1, wherein the Ag alloy thin film is a black matrix electrode film of a TFT-LCD by a light-shielding layer on-array method. 4. The Ag alloy thin film according to claim 1, wherein said reflective film is a reflective plate of a reflective TFT-LCD, a pixel electrode film serving as a liquid crystal drive electrode, or a reflective pixel electrode film having a role of a reflective plate and a pixel electrode. Alloy thin film. 5. An Ag alloy thin film according to claim 1, wherein said Ag alloy thin film is an address electrode film for a plasma display panel and a bus electrode. 6. A sputtering target for introducing an Ar gas into a vacuum apparatus and depositing the Ag alloy thin film on a substrate by sputtering, wherein the composition of the sputtering target is substantially Ag-Ru- Cu
Consisting of three element alloys, and the composition ratio is a weight fraction,
75 ≦ Ag <100 wt%, 0 <Ru <25 wt%, 0
An Ag alloy sputtering target, wherein Cu <25 wt%.