JP2002266068A - High-reflection and low-resistance thin film and sputtering target for deposition of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a high-reflection and low-resistance thin film which is useful as a reflection film, reflection electrodes, electrode, wiring, or the like, of a flat panel display(FPD), has high reflectivity, is stable, is low in electric resistance and is, in addition, excellent in film adhesion property and durability as well and a sputtering target usable for deposition of this thin film. SOLUTION: The high-reflection and low-resistance thin film is the film for forming the electrode, wiring, reflection film or reflection electrode of the FPD and is substantially formed of a ternary alloy of Ag-Ru-Au, in which the average reflectivity in a visible light region when the film thickness is 280 nm is >=88%, the difference in the magnitude of the reflectivity is within 10% and the electric resistivity is <=14 μΩcm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-reflection low-resistance thin film and a sputtering target for forming the thin film. More specifically, the invention of this application has high reflectivity, low electric resistance, film adhesion,
The present invention relates to a highly reflective low-resistance thin film having excellent durability and a sputtering target that can be used for forming the thin film.

[0002]

2. Description of the Related Art Conventionally, various metals have been used as various thin films formed as thin films as reflective films, reflective electrodes, electrodes, wirings, and the like provided on a flat panel display (FPD).

As such a thin film, an Au thin film or an Al or Al alloy thin film is often used for a reflective film or a reflective electrode. In addition, Al and A are used for electrodes and wiring.
1 alloy thin films and Cu and Cu alloy thin films are mainly used. However, these thin films have high reflectivity, electrical resistivity,
It has advantages and disadvantages in terms of film adhesion, various durability, price, patterning property, and the like, and a thin film excellent in all properties has not been realized.

To solve such a problem, for example, Au
A having the same high reflectance as that of A and relatively low electric resistance
It has been proposed to add a noble metal such as Pt or a modification accelerator such as Cu to g to use an Ag alloy thin film in which defects such as film adhesion, durability, and abrasion resistance relating to Ag are improved. ing.

On the other hand, when manufacturing an optical recording medium,
The light reflecting layer is made of, for example, an Ag-Ru alloy or R
By forming a thin film made of an Ag—Ru alloy to which at least one of h, Pd, Ir, Pt, and Au is added, the chemical stability is improved as compared with a light reflection layer made of Ag alone. A proposal has been made to improve the reliability and durability of the light reflecting layer (Japanese Patent Laid-Open No. 11-25515). However, this light reflection layer has a reflectance of only about 66 to 78% at a wavelength of 780 nm longer than that of visible light, and the reflectance of a shorter wavelength of visible light may be reduced to about 50%. However, it could not be said that the reflective film used for the FPD or the like was sufficiently satisfactory. Also, F
No consideration was given to etching, which is an essential step in the manufacture of PDs.

Therefore, the invention of this application has been made in view of the above circumstances, and solves the problems of the prior art, and is useful as a reflection film, a reflection electrode, an electrode, a wiring, etc. of an FPD. Provided is a high-reflection low-resistance thin film having high reflectance, high stability, low electrical resistance, excellent film adhesion and durability, and a sputtering target that can be used to form the thin film. That is the task.

[0007]

Accordingly, the invention of this application provides the following invention to solve the above problems.

That is, first of all, the invention of this application relates to a thin film for forming an electrode, a wiring, a reflective film or a reflective electrode of a flat panel display, which is substantially composed of Ag-Ru-Au. It is formed from an original alloy, and has an average reflectance of 88% or more in a visible light region when the film thickness is 280 nm, a difference in reflectance within 10%, and an electrical resistivity of 14 μΩcm or less. To provide a highly reflective low resistance thin film.

Secondly, the invention of this application is a sputtering target used for forming the high-reflection low-resistance thin film of the first invention, which is substantially composed of Ag-R.
It consists of a ternary alloy of u-Au, and its composition is
75 ≦ Ag ≦ 99.8, 0.1 ≦ Ru <25, 0.1 ≦
Provided is a sputtering target, wherein Au <25.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The invention of this application has the features as described above, and embodiments thereof will be described below.

First, the high-reflection low-resistance thin film provided by the first invention of this application is a thin film for forming an electrode, a wiring, a reflection film or a reflection electrode of a flat panel display, and is substantially a Ag-film. When formed from a Ru-Au ternary alloy, the average reflectance in the visible light region when the film thickness is 280 nm is 88% or more, the height difference of the reflectance is 10% or less, and the electric resistivity is 14 μΩcm or less. It is characterized by having.

A thin film made of Ag alone has excellent characteristics such as high reflectivity and low electric resistance, but has low adhesion to a substrate such as glass, so that the film is peeled off, or comes into contact with oxygen or heat treatment. There were drawbacks such as the diffusion and aggregation of Ag and the thin film surface becoming cloudy. The inventors of this application:
In order to eliminate the disadvantages without impairing the characteristics of the Ag thin film, it is necessary to combine two elements of Ru and Au into Ag and simultaneously add them as a reforming accelerator.
It was found to be extremely effective.

The addition of Ru and Au to Ag is more effective in improving the adhesion and durability than adding only one of Ru and Au. In the low-resistance thin film, Ag is mainly contained, and two elements of Ru and Au are added to form a ternary alloy of Ag-Ru-Au.

In the high-reflection low-resistance thin film made of the ternary alloy of Ag-Ru-Au, the contents of Ru and Au are preferably each 0.1% by weight or more.
If the amount is less than 0.1% by weight, the film adhesion decreases, the film peels off from the substrate, the durability is remarkably deteriorated, and the effect of modifying Ru and Au cannot be sufficiently obtained. Further, the total amount of Ru and Au is preferably less than 25% by weight. If the total amount of Ru and Au is 25% by weight or more, the surface of the obtained high-reflection low-resistance thin film becomes cloudy, and the high reflection characteristics and low electric resistance characteristics of Ag are impaired. Therefore, the composition of the high-reflection low-resistance thin film of the invention of the present application is expressed by 75%
g ≦ 99.8% by weight; 0.1 ≦ Ru <25% by weight;
1 ≦ Au <25% by weight.

In addition, the high-reflection low-resistance thin film of the present invention has both high reflection characteristics and low electric resistance.
Regarding the reflectance, for example, when the film thickness is 280 nm, the average reflectance is 80% over the entire visible light wavelength range.
As described above, more preferably, the average reflectance can be 85% or more. The high-reflection low-resistance thin film of the present invention is considered to have a high reflectivity in the entire visible light range of 10% or less, and to exhibit stable high-reflection characteristics as an excellent feature. Regarding the definition of “low electric resistivity”, 18 μΩcm or less corresponding to the resistivity of the Al-based thin film is considered as a practically suitable electric resistivity.

Further, the high-reflection low-resistance thin film of the invention of this application is excellent in various corrosion resistances, and does not show, for example, peeling of the film or corrosion such as white turbidity due to an etching solution. Therefore, in the manufacture of an FPD or the like, a thin film that can correspond to all of the electrodes, wirings, reflective films, reflective electrodes and the like is realized.

The high-reflection low-resistance film of the invention of the present application having such characteristics can be manufactured by a vapor phase film forming method such as sputtering, ion plating, and CVD. Among them, sputtering is exemplified as a preferable method because of its excellent film forming efficiency and film forming characteristics.
As the sputtering means, a batch type, an in-line type, or the like can be appropriately adopted. Furthermore, it is shown as a preferable example that the sputtering target provided by the second invention of this application is used as the sputtering target. Of course, the film may be formed by using a sputtering target other than the above or a multi-target using individual targets of Ag, Ru, and Au.

The sputtering target of the invention of this application is a sputtering target used for forming the high-reflection low-resistance thin film of the invention described above, and is substantially composed of Ag.
-Consisting of a Ru-Au ternary alloy whose composition is
And 75 ≦ Ag ≦ 99.8, 0.1 ≦ Ru <25, 0.
It is characterized in that 1 ≦ Au <25.

This sputtering target contains Ag as a main component, and the contents of Ru and Au can be determined according to the desired composition of the high-reflection low-resistance thin film. For example, the respective contents of Ru and Au in the sputtering target are also set in the range of 0.1 to 25% by weight so that the respective contents of Ru and Au are in the range of 0.1 to 25% by weight. Is exemplified. However, in any case, R
The total amount of u and Au is less than 25% by weight. This Ru,
Au is Ag, which is a main component of the sputtering target.
It is preferably added substantially uniformly throughout the entire sputtering target, but may be mixed in Ag in a stripe shape or a lattice shape, for example. In order to manufacture this sputtering target, for example, a conventional method such as a sintering method can be used.

In the invention of the present application, the definition of “substantially” means that the above-mentioned Ag, Ru is used as a metal element except for inevitable impurities derived from the raw material of the sputtering target material or the manufacturing process. , Au.

Embodiments of the present invention will be described below in more detail with reference to the accompanying drawings.

[0022]

EXAMPLES (Example 1) <A> 1% by weight of Ru and 1% by weight of Au were added to Ag, and the Ag-R of the invention of this application was obtained by a sintering method.
A sputtering target made of a u-Au ternary alloy was produced. This target was set to a transparent and clean plate thickness of 0.7
The glass substrate was disposed in a film forming apparatus so as to face a non-alkali glass substrate having a thickness of 1 mm.

Then, the inside of the film forming apparatus is kept constant at about 80 ° C., and the inside of the apparatus is sufficiently evacuated to a pressure of 3 × 10 ⁻³ Pa, and then Ar gas is introduced until the pressure becomes 0.27 Pa.
A thin film was formed on a glass substrate by sputtering the target at a power density of 3.5 W / cm ² for 300 seconds.

The obtained thin film was almost uniform with a thickness of 280 nm. When the composition of this thin film was analyzed by an energy dispersive X-ray analyzer (EDX) (manufactured by JEOL Ltd.), the ratio of Ag: Ru: Au = 98.6: 0.
3: 1.1, and the composition was confirmed to be uniform.

<B> The reflectance, electric resistivity and film adhesion of the thin film obtained in <A> above were evaluated.

The reflectance was measured using a spectrophotometer U-4100 manufactured by Hitachi, Ltd., and the specular reflection at an incident angle of 5 ° was measured. The result is shown as line A in FIG. For comparison, the result of similarly measuring the reflectance of the conventional Al thin film is shown as line B.

FIG. 1 shows that this thin film has a higher reflectivity over the entire visible light range than the conventional Al thin film, and has an average reflectivity of 8%.
It was 9.5%. In addition, the difference in the reflectance of this thin film was as small as 8.6%, and it was found that the decrease in the reflectance on the short wavelength side was gradual and stable.

The measurement of the electrical resistivity was performed using a four-pointed needle resistance meter. As a result, the electrical resistivity of this thin film is
The resistivity was 12.5 μΩcm, which was sufficiently lower than the resistivity of the conventional Al thin film of about 18.0 μΩcm.

The adhesion was evaluated using a cellulose tape (3M
(No. 6101 1/2 inch width, manufactured by the company) and a cellophane tape test method. as a result,
This thin film did not peel off from the glass substrate, and was confirmed to be excellent in adhesion. For example, it is known that a pure Ag thin film or the like has poor adhesion. However, it is presumed that the adhesion of this thin film is greatly improved by adding an appropriate amount of Ru and Au to Ag. You.

<C> Six types of durability tests shown in Table 1 were conducted on the thin film formed on the glass substrate according to <A>. The six types of test items in Table 1 generally indicate the conventional Ag thin film and Ag in the manufacturing process of FDP.
This is a disadvantage that alloy thin films are said to have in terms of durability.

[0031]

[Table 1]

With respect to the thin film after each test, the presence or absence of film peeling and pinholes was observed, and before and after the test, changes in the film color, electric resistivity, and optical density were examined. As a result, no peeling or pinhole generation was observed in the thin film after each test, and no change was observed in the film color, electric resistivity, and optical density. From the above results, this thin film is composed of sulfur compounds, moisture,
It was confirmed that it had resistance to acids and alkalis. Therefore, the thin film of the invention of this application is, for example,
It has been shown that the method can sufficiently cope with production of electrodes, wirings, reflection plates, reflection electrodes and the like for FPD.

<D> The thin film of the invention of this application formed on the glass substrate by <A> was etched to form a wiring pattern. The etching solution contains C
165 g of e (NH ₄ ) ₂ (NO ₃ ) ₆ , 70% HClO ₄
Was mixed at a ratio of 42 ml and H ₂ O at a ratio of 1000 ml,
An etching solution having a liquid temperature of 30 ° C. was used.

The etched cross-sectional shape of the wiring pattern formed by the Ag-based thin film had almost no scuffing of the film, the pattern width was uniform, and no corrosion such as peeling of the film or clouding was observed. From this result, it was confirmed that the thin film of the invention of this application was excellent in etching properties.

The components of the above-mentioned etching solution are almost the same as those of the chromium etching solution frequently used when patterning a Cr thin film to form a wiring. Therefore, when etching the thin film of the invention of this application,
Existing patterning manufacturing equipment and methods can be diverted as they are.

Of course, the present invention is not limited to the above examples, and it goes without saying that various embodiments are possible in detail.

[0037]

As described in detail above, the present invention is useful as a reflection film, a reflection electrode, an electrode and a wiring of an FPD, has a high reflectance, is stable, has a low electric resistance, and has a high film adhesion. In addition, a high-reflection low-resistance thin film having excellent durability and a sputtering target that can be used for forming the thin film are provided.

[Brief description of the drawings]

FIG. 1 shows a thin film (A) formed in an embodiment and a conventional thin film (A).
It is the figure which illustrated the result of having measured the reflectance about 1 thin film (B).

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01J 29/28 H01J 29/28 (72) Inventor Hiromitsu Satake 1 Hanamizue, Takeyari Wakayanagi-cho, Kurihara-gun, Miyagi Prefecture -1 Inside Kuramoto Manufacturing Co., Ltd. F-term (reference) at Toshima Works 2H092 HA05 KB04 MA05 NA25 NA27 NA28 PA12 4K029 AA09 BA22 BC07 BD09 CA05 DC04 DC09 5C036 BB04 5C094 AA04 AA22 AA24 AA32 AA37 AA42 AA43 AA55 DA13 EA00 EA12 JA05 JA02 JA05

Claims (2)

[Claims] An electrode for a flat panel display,
A thin film for forming a wiring, a reflection film or a reflection electrode, which is substantially formed of a ternary alloy of Ag-Ru-Au and has an average reflectance in a visible light region when the film thickness is 280 nm. 88% or more, the difference in reflectance is 10
% And an electrical resistivity of 14 μΩcm or less. 2. A sputtering target used for forming the high-reflection low-resistance thin film according to claim 1, wherein the sputtering target is substantially composed of a ternary alloy of Ag—Ru—Au, and has a composition by weight%. , 75 ≦ Ag ≦ 99.8, 0.1 ≦ Ru <
25. A sputtering target, wherein 0.1 ≦ Au <25.