JP2720919B2 - target - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a target used for producing an amorphous oxide film which is transparent and has excellent durability.

[Prior art] Conventionally, a thin film is formed on a transparent substrate such as glass or plastic and added with an optical function by using a mirror,
There are heat ray reflection glass, low radiation glass, interference filters, and anti-reflection coatings for camera lenses and eyeglass lenses.

In a normal mirror, Ag is formed by an electroless plating method, or Al or Cr is formed by a vacuum evaporation method, a sputtering method, or the like. Of these, the Cr film is relatively tough, and is therefore used partially as a surface mirror with an exposed coated surface.

Heat ray reflective glass has been formed of titanium oxide, tin oxide, or the like by a spray method, a CVD method, an immersion method, or the like. Recently, a metal film, nitride film, tin-doped indium oxide (ITO) or the like formed on a glass plate surface by a sputtering method has come to be used as a heat ray reflective glass. In the sputtering method, the film thickness can be easily controlled and a plurality of films can be formed continuously, and the transmittance, the reflectance, the color tone, and the like can be designed in combination with the transparent oxide film. For this reason, demand has been increasing for architectural applications and the like that emphasize designability.

Low-emissivity glass, which reflects radiant heat from indoor heaters and walls to the indoor side, is a ZnO / Ag / ZnO / ZnO / Ag / ZnO / Ag / ZnO layer with silver sandwiched by zinc oxide. / Zn
It has a five-layer system of O (see JP-A-63-134232) and is used in the form of double-glazed or laminated glass. In recent years, it has been remarkably popular in cold regions in Europe.

An anti-reflection coating such as a lens is formed by alternately laminating a high-refractive-index film such as titanium oxide or zirconium oxide and a low-flexibility film such as silicon oxide or magnesium fluoride. Normally, a vacuum evaporation method is used, and the substrate is heated during film formation to improve the scratch resistance.

[Problems to be Solved by the Invention] Surface mirrors, antireflection coatings such as short-plate heat ray reflection glass and lenses are used in a state where the coated films are exposed to the air. Therefore, it must be excellent in chemical stability and abrasion resistance. On the other hand, even in the case of low-emission glass, defective products are generated due to scratches during transportation or handling before becoming double-layer glass or laminated glass. For this reason, a protective film which is stable and excellent in wear resistance or an optical thin film which also serves as a protective film is desired.

To improve durability, a chemically stable and transparent oxide film is usually provided on the air side. These oxide films include titanium oxide, tin oxide, tantalum oxide, zirconium oxide, silicon oxide, and the like, and have been selected and used according to required performance.

However, titanium oxide and zirconium oxide are excellent in chemical stability, but tend to become a crystalline film, and the surface irregularities tend to be large, so that the friction when rubbing becomes large and the wear resistance is poor. .

On the other hand, tin oxide and silicon oxide are weak to acids and alkalis, respectively, and cannot withstand long-term immersion. Among these, tantalum oxide has both abrasion resistance and chemical stability, but is not yet satisfactory with respect to abrasion resistance.

Titanium oxide, tin oxide, tantalum oxide, and zirconium oxide have relatively high flexural factors, while silicon oxide has a relatively low refractive index. In order to provide various optical functions, the degree of freedom in optical design is limited. is there.

There is no known target capable of efficiently producing a thin film having high durability and a wide degree of freedom in optical design.

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems, and is a non-oxide target for DC sputtering comprising Zr and B, wherein Zr has 91 to 20 atoms. %, B is 9-80 atomic%.

The present invention also relates to a non-oxide target for DC sputtering comprising Zr and Si, wherein Zr is 50 to 10 atomic% and Si is
Provide a non-oxide target that is 50-90 atomic%.

The present invention also provides a non-oxide target for DC sputtering comprising Zr, Si, and B, wherein Zr is 33 to 5 atomic%,
A non-oxide target having 33 to 90 atomic% of Si and 33 to 5 atomic% of B is provided.

The present invention is a thin film in which an amorphous oxide containing at least one of Zr and B or Si is excellent in scratch resistance, abrasion resistance, chemical durability, and also has flexibility in optical design. It is made by finding out that.

Although the composition of the amorphous oxide film is not particularly limited, zirconium, boron, and silicon oxide films should be ZrO ₂ , B ₂ O, respectively, in order to make the film amorphous and improve scratch resistance and reliability. _3, when representing a SiO _2, with respect to ZrO ₂ 100 parts, B ₂ O _3, the total of oxides selected from SiO _2, in a molar ratio of 5 parts or more, preferably 10 parts or more, particularly more than 20 parts Is good.

In the case of B ₂ O _3, too large and reliability, particularly chemical durability is lowered, depending on the application, 200 parts or less preferably 100 parts by mole ratio relative to ZrO ₂ 100 parts, particularly 50 parts The following is good. In the case of SiO ₂ , if it is too much, the durability against alkali is reduced. Therefore, the molar ratio to ZrO ₂ 100 parts is 1900 parts or less, preferably 900 parts or less, particularly 400 parts or less.

Table 1 shows properties of various amorphous oxide films. Films were formed by reactive sputtering using targets having the compositions shown in the table. Even if the same target is used, the target may slightly vary depending on the film composition and the film forming conditions. Table 1 shows only an example.

 The crystallinity was observed by thin film X-ray diffraction.

The abrasion resistance is the result of the rubbing test using a sand eraser.
Indicates that scars were scarcely formed, and x indicates that scratches were easily generated.

Abrasion resistance is measured by Taber test (wear theory CS-10F, weight 500
g, 1000 rotations), those with a haze of 4% or less were evaluated as ○, and those with a haze of more than 4% were evaluated as x.

Acid resistance was determined by immersing in 0.1NH ₂ SO ₄ for 240 hours.
_{When the} change rate of _V (visible light transmittance) and R _V (visible light reflectance) with respect to before immersion was within 1%, the film was dissolved and disappeared. Those were marked as x.

As a result of immersion in 0.1N NaOH for 240 hours,
If the rate of change of T _V or R _V before immersion is within 1%,
A sample within 2% was rated as Δ, and one in which the film was dissolved was rated X.

Boiling test, one atmosphere, was immersed for 2 hours in 100 ° C. water, when T _V, the rate of change for the previous immersion R _V is within 1% ○, and as × when 1 percent.

As is clear from Table 1, the ZrB _x O _y film tends to form a crystalline film when the amount of B in the film is small, and to form an amorphous film when the amount of B is large. It can be seen that a crystalline film is inferior in scratch resistance and abrasion resistance, whereas an amorphous film is excellent. This is presumably because the amorphous film has a smooth surface. Therefore, a ZrB _x O _y film (where the atomic ratio x of B to Zr in the film x is 0.1 <x) is excellent in scratch resistance and abrasion resistance. Since the B ₂ O ₃ film is hygroscopic and absorbs and dissolves moisture in the air, it is preferable that x <4 in the ZrB _x O _y film.

The atomic ratio of O (oxygen) to Zr in the ZrB _x O _y film is not particularly limited, but if it is too large, the film structure becomes coarse and the film becomes uneven, and if it is too small, the film becomes metallic. It is preferable that the amount is such that the composite system of ZrO ₂ and B ₂ O ₃ is formed because the transmittance tends to decrease or the scratch resistance of the film tends to decrease. That is, the composite oxide is converted to ZrO ₂
When expressed as + xBO _1.5 , it is preferable that y = about 2 + 1.5x when B has an atomic ratio x with respect to Zr.

Also, from Table 1, as the amount of B in the ZrB _x O _y film increases,
It can be seen that the refractive index of the film tends to decrease. FIG. 1 shows the relationship between the composition of the film and the refractive index n. By increasing B in the film, the refractive index n decreases from about 2.14 to about 1.46.

Therefore, the ZrB _x O _y film of 0.1 <x <4,2 <y <8 has good scratch resistance and abrasion resistance, and the refractive index can be freely selected depending on the amount of B. It is a membrane.

Furthermore, as shown in Table 1, as the content of B in the film increases, the acid resistance and alkali resistance tend to deteriorate. When x ≧ 2.3, the acid resistance deteriorates, and when x ≧ 4, the alkali resistance decreases and the boiling test shows deterioration. Therefore, for applications requiring high chemical durability, such as those used in the state of being exposed in air, ZrB _x O _y (x <2.
The amorphous oxide film of 3) is preferable, and ZrB _x O _y (x ≧ 2.
The film of 3) can be used as a low refractive index film in other applications.

As described above, it is considered that the addition of B to the ZrO ₂ film makes the film amorphous and smoothes the surface, which contributes to the improvement of wear resistance and scratch resistance. In addition, the refractive index can be adjusted by the amount of B, and further, compared with the ZrO ₂ film,
Since the internal stress is small, it is advantageous in terms of adhesion to a substrate (glass, plastic, etc.) and a base film on the substrate. This is particularly advantageous when forming a thick film.

Next, as for the ZrB _x O _y film, from Table 1, a film which is also amorphous and has high scratch resistance and abrasion resistance can be obtained.

Regarding the refractive index, ZrO ₂ (n = 2.14) and SiO ₂ (n = 1.
46) depending on the composition ratio (see FIG. 2).

In the ZrSi _z O _y film, 0.05 ≦ z (Si with respect to Zr in the film)
Is preferably 19 or less. If z <0.05,
The film does not become amorphous, and sufficient physical durability cannot be obtained.
When z ≧ 19, the alkali resistance is deteriorated. Also, y (Zr
The atomic ratio of 0 (oxygen) to Zr in the B _x O _y film is ZrSi _z O
For the same reasons as described for the _y film, ZrO ₂ and SiO ₂
When Si is included in z at an atomic ratio to Zr, it is preferable that y is about 2 + 2z.

Therefore, for applications that are used in the state of being exposed in air, 0.
A ZrB _x O _y film satisfying 05 ≦ z <19, 2.1 ≦ y <40 is preferable, and 19 ≦ z
ZrB _x O _y film, in other applications, can be used as a low refractive index film.

For the ZrB _x Si _z O _y film, the atomic ratio of B to Zr
The atomic ratio z of x and Si and the atomic ratio y of O (oxygen) are x + z ≧ 0.
05 is preferable because the film becomes amorphous and becomes a film having high scratch resistance and abrasion resistance. Also, if x + z <19, the alkali resistance is also good, so in the ZrB _x Si _z O _y film,
It is preferable that 0.05 ≦ x + z <19. However, as described above, since the melts by supplying moisture in the air in the B ₂ O ₃ hygroscopicity, better not contained too much in the ZrB _x Si _z O _y film.

Specifically, in the film, Zr and B excluding O (oxygen)
If Zr <25 at% and Si <25 at% with respect to the total amount of Si and B is included so that the balance becomes B, the chemical durability becomes insufficient. That is, _if Zr: B: Si (atomic ratio) in the ZrB _x Si _z O _y film is 1: x: z, 1 / (1 + x + z) <0.25 and z
The composition of /(1+x+z)<0.25, that is, x + z−3> 0 and x−3z + 1> 0 has poor chemical durability.

y is considered to be a composite system of ZrO ₂ + B ₂ O ₃ + SiO ₂ for the same reason as described in the case of ZrB _x O _y , and y is 2 + 1.
It is preferable to be about 5x + 2z. Therefore, almost 2 <y <
It is preferably about 40. The higher the content of B and Si, the more
The refractive index of the ZrB _x Si _z O _y film decreases. FIG. 3 shows an example of the ZrB ₁ Si _z O _y film.

The amorphous oxide film is composed of elements other than Zr, B, Si, O, for example, B, S
Like i, glass constituent elements such as P and As may be contained in trace amounts for the purpose of improving durability, adjusting optical constants, stability during film formation, improving film formation speed, and the like.

The thickness of the amorphous oxide film is usually preferably from 100 to 5000 °. If it is too thin, sufficient scratch resistance cannot be obtained, and if it is too thick, peeling of the film tends to occur,
This is because productivity is poor.

A sputtering method is used as a method for manufacturing the amorphous oxide film. The sputtering method has advantages in that the raw material is not melted, the control of the film composition and reproducibility are good, the energy of the particles reaching the substrate is high, and a film with good adhesion can be obtained.

It is known that, in the sputtering method, a film is formed in a glow discharge plasma, so that a floating potential of several to several tens of volts is generated on a substrate without applying a voltage. Some of the Ar ions in the plasma are accelerated by this floating potential and enter the substrate being formed. As a result, a mixed layer formed by implanting a part of the atoms constituting the film at the boundary between the substrate and the underlying film is formed, and the bonding between the layers is strengthened. The rearrangement is effectively performed, and the densification of the film is promoted.

Therefore, in the sputtering method, a film which is dense, has a high film hardness, and has excellent adhesion to a substrate or a base film can be obtained as compared with other vacuum film forming methods such as a vapor deposition method. In addition, the densification of the film structure reduces structural defects such as vacancies and interstitial atoms, which cause film stress. Therefore, oxides such as Si and B are doped with a component that is a network former. Together with the effect of making the structure amorphous, there is also a remarkable effect in reducing the film stress of the obtained film.

In addition, Si oxide itself has much higher hardness than ordinary soda lime glass, like Zr oxide, and therefore, a two-component film or a three-component film containing Si oxide is a multi-component film. In addition to the effects of amorphization and densification of the structure, high film hardness is realized also in terms of material.

As described above, in addition to the effect of the multi-component film composition by using the sputtering method, in addition to the effect of abrasion resistance, such as densification of the film, good adhesion, low film stress, and high film hardness. The properties essential for achieving excellent mechanical durability can be further improved. As a result, the amorphous oxide film formed by sputtering exhibits extremely excellent scratch resistance.

The ZrSi _x O _y film can also be formed by a wet method such as a sol-gel method. However, in the production method using such metal organic substances, decomposition reaction of raw materials, removal of organic substance components,
In order to make the progress of the sintering reaction complete, a firing step at several hundred degrees Celsius, usually 600 to 850 ° C., is required. Therefore, when the processing temperature is limited due to thermal degradation or process cost of other film materials that make up the coating, undecomposed raw materials and organic components remain in the film by the wet method, and the structure is densified by the firing reaction. Is insufficient, resulting in a serious problem that the chemical or mechanical durability of the film is significantly reduced.

On the other hand, in the sputtering method, a film having excellent durability chemically and mechanically can be obtained without particularly heating the substrate by the mechanism described above. Of course, it is also possible to form a film on a heated substrate as needed.

When forming an amorphous oxide film by a sputtering method,
Zr and at least one of boron (B) and silicon (Si)
A non-oxide target composed of a seed is used. For example, when forming a film such as ZrB _x O _y , ZrSi _x O _y , ZrB _x Si _z O _y , zirconium boride single system, zirconium silicide single system, zirconium boride-metal zirconium composite System, zirconium boride-zirconium silicide composite system,
Zirconium boride-metal silicon composite system, zirconium boride-boron composite system, zirconium silicide-metal zirconium composite system, zirconium silicide-boron composite system,
Non-oxidation of zirconium silicide-metal silicon composite system, zirconium boride-zirconium silicide-metal zirconium composite system, zirconium boride-zirconium silicide-metal silicon composite system, zirconium boride-zirconium silicide-boron composite system, etc. Reactive sputtering in a vacuum of about 1 × 10 ⁻³ to 1 × 10 ⁻² Torr in a mixed atmosphere of Ar ⁺ oxygen using a target of single substance or non-oxide composite system forms a uniform film. Can membrane.

If the pressure is less than 1 × 10 ⁻³ Torr, the discharge becomes unstable and 1 × 10 ⁻²
If the pressure is higher than Torr, sputtered particles collide with each other, and the film forming speed is reduced. Since these non-oxide targets have conductivity, they can be formed by a direct current sputtering method, so that a uniform film can be formed over a large area at high speed.

When reactive sputtering is performed using a non-oxide-based target, the ratio of B, Si to Zr in the target is, as apparent from Table 1, the ratio of B, Si in the film formed using the target. It tends to be almost retained.

Considering the above tendency, ZrB _x O _y (0.1 <x <4,2
<Y <8) When a film is formed by reactive sputtering, Zr
A target composed of 91 to 20 atomic% and B9 to 80 atomic% is used. Similarly, there is a target composition required for the ZrSi _z O _y ZrB _x Si _z O _y film.

When performing a reactive sputtering using a non-oxide target, a transparent film can be formed by increasing the proportion of oxygen in the atmospheric gas, but the film forming rate gradually decreases. Therefore, in order to form a film at a high film forming rate, it is necessary to suppress the oxygen concentration in the atmosphere gas to a certain degree, that is, to form a film in an oxygen concentration range of a transition region where an absorptive film changes to a transparent film. As described above, it is very difficult to control so that sputtering is performed in the transition region.

Since the composition of the target and the composition of the film formed using the target vary somewhat depending on the film forming conditions, they cannot be uniquely determined. The example shown in Table 1 is one embodiment.

The aforementioned target can be formed, for example, by the following method. Metal zirconium, boron, metal silicon,
A single or composite target of the present invention is formed by firing at least one powder or mixed powder of zirconium boride and zirconium silicide in a high-temperature high-pressure press, a high-pressure press, or a high-pressure press. Is done. In this case, the particle size of the powder is 0.05 μm to 40 μm
Is appropriate.

The above-mentioned target may contain iron, aluminum, magnesium, calcium, yttrium, manganese, and hydrogen in a total of 2 wt% or less. Since carbon becomes CO ₂ and disappears during film formation, carbon is reduced to 2 wt%. It was confirmed that the characteristics were the same even if they were included below. Further, the same effect can be obtained by mixing copper, niobium, vanadium, chromium, molybdenum, tungsten, cobalt, rhodium, iridium or the like in the target of the present invention.

[Action] When B and / or Si is added to the oxide of Zr,
Alternatively, it is considered that Si destroys the lattice of such an oxide, hinders the growth of crystal grains of such an oxide, and makes the film more amorphous.

It is considered that the unevenness of the film surface is smaller in the amorphous film than in the film that is a set of microcrystals. As a result, it is considered that the amorphous film has a reduced friction coefficient. For this reason, it is considered that the amorphous film is extremely excellent in lubricating properties and has little catching, so that it is hard to be scratched by friction, and high scratch resistance and high wear resistance can be obtained.

[Effect] According to the present invention, B or /
In addition, it is possible to provide a target capable of producing a thin film having a degree of freedom in optical design that can control a bending rate by an addition amount of Si.

By using the target of the present invention, an amorphous oxide film having high durability can be uniformly formed at high speed over a large area.

Since the amorphous oxide film has high scratch resistance and high wear resistance, it can be used as an overcoat for various articles. For example, it is formed directly on a substrate such as glass, plastic, or other substrates or films to make the surface harder to grind, or a heat-reflecting glass for an architectural vehicle, an electromagnetic wave shielding glass, an antistatic glass, and other materials. It is most suitable for glass with a functional film, a protective plate for a reading part of a barcode reader, and an outermost layer such as an antireflection film and an eyeglass lens. or,
It is widely used for mechanical elements and can be used as a coating material for sliding members.

Particularly, a ZrB _x O _y (0.1 <x <2.3, 2 <y <5.5) film, a ZrSi _{z
O y (0.05 ≦ z <19,2.1} ≦ y <40) _{film, ZrB x Si z O y (} 0.05
≦ x + z <19 (where x + z−3> 0 and x−3z + 1
> 0), and 2 <y <40) since the film has not only abrasion resistance and abrasion resistance but also very excellent chemical durability, it can be used in applications where the use environment is severe. In an architectural or vehicle heat ray reflective glass used as a veneer, it can be used as a protective layer as the outermost layer.

As described above, since the amorphous oxide film can change the refractive index with a considerably large degree of freedom, even when the outermost layer of the multilayer coat film is used also as a protective role, interference with the lower layer can be prevented. Can be freely controlled, so that it can be easily incorporated into a wide range of multilayer films, and its application range is very wide.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship between the content of B in a ZrB _x O _y film and the refractive index n of the film. FIG. 2 is a diagram showing the relationship between the content of Si in the ZrSi _z O _y film and n. FIG. 3 shows ZrB ₁ Si _z O _y
FIG. 4 is a diagram showing the relationship between the content of Si in a film and n.

 ──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-52-138512 (JP, A) JP-A-61-51333 (JP, A) JP-A-61-34501 (JP, A) JP-A-2- 901 (JP, A)

Claims (3)

(57) [Claims] 1. A non-oxide target for DC sputtering comprising Zr and B, wherein Zr is 91 to 20 atomic% and B is 9 to 80 atomic%.
Non-oxide target which is atomic%. 2. A non-oxide target for DC sputtering comprising Zr and Si, wherein Zr is 50 to 10 atomic% and Si is 50 to 90%.
Non-oxide target which is atomic%. 3. A non-oxide target for direct current sputtering comprising Zr, Si and B, wherein Zr is 33 to 5 atomic% and Si is 33% by atom.
A non-oxide target having ~ 90 at% and B at 33-5 at%.