JPS5918134A - Manufacture of heat reflecting laminate having oxide film - Google Patents

Abstract

PURPOSE:To manufacture a high-performance heat reflecting glass having excellent weatherability, by applying a thin film of a metal having high infrared reflection in the form of being sandwiched between a pair of thin films of a specific metal oxide, to a substrate such as glass. CONSTITUTION:A substrate plate such as glass is cleaned, put into a vacuum chamber, and heated at 100-150 deg.C while evacuating the vacuum chamber. A mixture of argon and oxygen having an oxygen concentration of 5-30% is introduced into the vacuum chamber, and a thin Bi2O3 film having a thickness of about 400Angstrom is deposited to the glass substrate by the reactive sputtering process using metallic Bi as the target. A thin film of Au or Ag, etc. of 50- 300Angstrom thick is formed to the surface of the Bi2O3 thin film by using a metal t arget such as Au, Ag etc. while keeping the atmosphere of the vacuum chamber unchanged, and the metallic film is coated with a Bi2O3 thin film. The produced reflecting glass has high transmittance of visible light, high reflection to IR radiation or the light having longer wavelength than IR radiation, and excellent surface weatherability.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing high-performance heat-ray reflective glass.

In recent years, from the viewpoint of energy conservation, window glasses of buildings and other structures have been required to have high heat-insulating properties. Metal films are useful in terms of heat reflection, but among them, Au, Ag,
Films such as AI and Ou are widely used. However,
Such single-layer metal films tend to undergo migration, oxidation, etc. of metal atoms during use, and do not have sufficient weather resistance, and also do not have sufficient mechanical strength such as adhesion and scratch strength.

As a countermeasure to these problems, it is widely used to create a multilayer structure by combining a metal layer such as Au, Ag, Ou, A1, etc., which has high infrared reflectivity, with a dielectric film such as an oxide. There is. For example, if an oxide layer is inserted between the substrate surface and the metal film, the adhesion force will be significantly increased compared to the case of a single metal layer. This is because the oxide thin film has a covalent bond with the glass through oxygen atoms, and with the metal film, it acts as a mediator between the two through a metal bond through the metal atoms. Furthermore, if an oxide film is formed on the metal film, the oxide film serves as a protective film and weather resistance is improved. Furthermore, if the above two structures are combined to form a three-layer structure consisting of a first oxide layer, a second metal layer, and a third oxide layer,
In addition to improving the weather resistance and mechanical strength mentioned above, by adjusting the film thickness of each layer, a high visible light transmittance that cannot be obtained with a single layer of metal film, for example, a transmittance of about 80%, is achieved. It is also possible to do so. In addition, the reflectance of visible light can be lowered, and this serves to prevent reflected light pollution, which is often a problem when metal single-layer films such as Au, Ag, and O are used in buildings, etc.

A method for forming such an oxide thin film by sputtering is a method in which sputtering is carried out in a normal inert gas atmosphere using a sintered target made of the target oxide as the target, and There is a method in which a metal target made of a metal component is used to perform reactive carbon sintering in a mixed gas atmosphere of an inert gas and an oxygen gas. Although the method using an oxide target is easier to obtain reproducibility than reactive sputtering, it takes time and effort to mold the target, and the target cannot be recycled for use. Furthermore, except for some oxides such as tin oxide and indium oxide, D, O, and sputtering cannot be performed on them. On the other hand, if a metal target is used, D, C, sputtering is possible, the target is relatively easy to mold, and it can be recycled and used. However, in order to obtain an oxide film from a metal target, the proportion of oxygen gas in the sputtering atmosphere must be increased considerably. And in such an atmosphere, Au,
Ag, Ou.

If sputtering of A1 or the like is performed, the reflection characteristics of the metal in the near-infrared region or above are significantly reduced, resulting in a reduction in heat ray reflection performance. In order to avoid such a situation, it is necessary to change the atmosphere in the vacuum chamber when forming each layer of the metal layer and the oxide layer, which is a disadvantageous condition in terms of productivity.

In order to improve this point, the present inventor conducted research and found that Au is difficult to oxidize as a metal film.

B1, which easily oxidizes Ag, A1, etc., as an oxide film
It has been discovered that by selecting an oxide such as the following, it is possible to form a five-layer film in the same atmosphere by adjusting the conditions.

Regarding the proportion of oxygen gas in the sputtering atmosphere when forming an oxide film from the metal target of B1, as long as the formation rate of the oxide film is kept below 10λ/θeC, around 30% is sufficient; For example, it is possible to form an oxide film with a smaller proportion of oxygen gas. The oxide film of B1 that was formed did not completely reach the 1203 shape and was in a slightly oxygen-deficient state. in wavelength,
There is absorption with an optical constant value of about 0.08.

On the other hand, when Agt is sputtered in the above-mentioned atmosphere, the optical properties in the infrared region and in the visible region are not significantly different from those obtained in a normal inert gas atmosphere unless the formation rate is drastically reduced. A membrane is obtained.

Under the above film formation rate conditions and sputtering atmosphere, B1 oxide/A [1! ;/When three-layer sputtering of B i oxide was performed in the same atmosphere and the spectral characteristics of the resulting three-layer film were measured, it was found that the reflection characteristics in the near-infrared and infrared regions of 700 mμ or more were significantly reduced. There was found. The cause of the sagging phenomenon is that the Ag film obtained by sputtering in a mixed gas atmosphere is inferior in mechanical strength to the Ag film obtained by sputtering in an atmosphere containing only an inert gas. B1 on top of Ag film
The structure of the Ag film is destroyed when forming the oxide film. This is because the above phenomenon did not occur even when a 6-layer film was created in an inert gas atmosphere using an oxide target, and when a 3-layer film was created in a mixed gas atmosphere. However, this was confirmed by the fact that by reducing the thickness of the B1 oxide layer on the Ag film, the degree of deterioration in the reflection performance in the near-infrared and infrared regions can be suppressed.

It is thought that the cause of the Ag film taste failure caused by the monoxide film is the difference in internal stress between the two.

Therefore, the present inventors attempted to preheat the temperature of the substrate to 100 to 150° C. during sputtering in order to alleviate both internal stresses. As a result, the three-layer film obtained under these conditions has excellent reflective properties even in the near-infrared region and beyond.
It was found to be highly valuable as a heat ray reflector.

The effect of increasing the temperature of the substrate on the Ag film is not considered to be so large at this temperature, and the B1 oxide layer existing between the Ag film and the substrate acts as a mediator that prevents Ag migration due to heating. working. However, it is thought that if heated above this temperature range, the microclision of Ag will no longer be blocked. Also, if the thickness of the Ag film is too thin, destruction and migration are likely to occur (~, from the viewpoint of heat ray reflectivity, the effect of an extremely thin Ag film is small. Also, conversely, if the Ag film is too thick) This results in a decrease in transmittance in the visible range, which is undesirable.For this reason, the thickness of the highly infrared reflective metal is preferably 50 to 300 Å.

As described above, according to the present invention, when creating an oxide/metal/oxide type heat ray reflective laminate having heat wire drawing performance, Ag is used as the metal.

If a material that is easily oxidized such as AI or Au is selected, and a material composed of an easily oxidized metal such as B1 is selected as the oxide, the temperature of the substrate is 100 to 150° α. Five layers can be formed in the same atmosphere under conditions of a ratio of 5 to 30 inches.In particular, by heating the substrate, internal stress is relaxed, making it easy to create a three-layer film.

Examples of the present invention will be described below.

Example 1 A 2.5-inch thick soda-lime glass substrate whose surface was cleaned by polishing was placed in a vacuum chamber and heated to 1 t OX using an oil diffusion pump.
The glass substrate is evacuated to 0-6 Torr or less and heated to 100-110°C. A mixed gas of oxygen and argon containing 30% oxygen gas is introduced into the vacuum chamber, and the degree of vacuum is adjusted to 4, Ox 10"-' Torr. A voltage of α8 to 1. Sputtering is performed to obtain a 400A thick B1 oxide thin film on a glass substrate.Next, a voltage of 2.2 to 2.4 KV is applied to the Ag target without changing the atmosphere, and a 20OA thick film is formed on the B1 oxide thin film. Ag, a thin film was formed.Finally, the B1# compound thin film kAg thin film was coated again at 400X.
Formed. This 6-layer coating is performed using an RF magnetron snort device, and since both the Ag target and B1 target can be placed in the vacuum chamber at the same time,
Of course, the B1 oxide layer mentioned above was implemented without breaking the vacuum.

Each Ag layer was coated in the same atmosphere without changing the W atmosphere. When the optical properties of the obtained film were measured, the average visible light transmittance was 53.9%, and the average visible light reflectance was 51.
It was 24. In addition, the solar energy reflectance was 49.4% and the transmittance was 267%.

A spectral characteristic diagram of such a heat ray reflective glass is shown in FIG.

In FIG. 1, 1 indicates transmittance and 2 indicates reflectance.

Example 2 A 400A B was deposited on a glass substrate in the same manner as in Example 1.
1 oxide thin film, 100A Ag thin film, 400X B
Monooxide thin films were sequentially laminated. Note that the voltage applied when creating each film was the same as in Example 1, and the film thickness of each layer was adjusted by changing the sputtering time. When the optical properties of the obtained film were measured, the average transmittance of visible light was 55.2, and the average reflectance of multiple viewing light was 12.0.
It was Chi. The solar energy reflectance was 22.4 cm, and the solar transmittance was 47.1%. A spectral characteristic diagram of such a heat ray reflective glass is shown in FIG. In addition, in Figure 2, 3
indicates transmittance, and 4 indicates reflectance.

Comparative Example A thin film of B1 oxide of 30OA, a thin film of Ag of 100A, and a thin film of B1 oxide of 500λ were formed on a glass substrate in the same manner as in Example 1, except that the glass substrate was kept at room temperature without heating. were sequentially stacked. Since the sputtering time for each layer was relatively short, almost no increase in substrate temperature due to sputtering was observed. When the spectral characteristics of the obtained heat ray reflective glass were measured, as shown in Fig. 3, it was found that 70
In the wavelength range of 0 mμ or more, the characteristics of both transmittance and reflectance deteriorated. In addition, in Fig. 3, 5 is the transmittance, and 6 is the transmittance.
indicates reflectance.

As described above, according to the present invention, a five-layer structure film of oxide/metal/oxide can be created in the same atmosphere without destroying the metal film, which provides favorable conditions for mass production. .

[Brief explanation of drawings]

1 and 2 are spectral characteristic diagrams of a heat ray reflective glass according to the method of the present invention, and FIG. 5 is a spectral characteristic diagram of a heat ray reflective glass according to a comparative example. Bud 3-)■

Claims (6)

[Claims] (1) In a method of forming a laminate of a metal film and an oxide film on a substrate surface by reactive sputtering, a mixed gas of an inert gas and oxygen gas is used as the sputtering gas, and the metal film and oxide film are A method for forming a laminate, characterized in that both films are formed without changing the sputtering atmosphere. (2) The method for forming a heat ray reflective laminate according to claim 1, wherein the sputtering gas has an oxygen concentration of 5 to 30%. (3) A method for forming a heat ray reflective laminate according to claim 1, characterized in that the substrate is heated to 100 to 150°C. (4) A method for forming a heat ray reflective laminate according to claim 1, characterized in that a metal is used as a target for the oxide film. (5) Claim 1, characterized in that the structure of the laminate has a five-layer structure in which the first layer is an oxide layer, the second layer is a metal film layer, and the fifth layer is an oxide film layer. A method for forming a heat ray reflective laminate as described in . (6) A method for forming a heat ray reflective laminate according to claim 1, wherein at least one of Ag, Au, and AI is used as the metal film, and the film thickness is 50 to 600 mm. .