JPS61209401A - Incremental reflection mirror - Google Patents

Abstract

PURPOSE:To obtain the titled mirror having a high reflectivity, a high density and a high hardness which is un-necessary to heat the substrate by using an reactive ion plating method, and by constituting the incremental reflection film of a metal with a metal oxide only, and then by covering the upper most layer with a thin film of SiO2. CONSTITUTION:The Al film 15 is formed on the substrate in a thickness of 700Angstrom as the first layer by a high frequency ion plating method of an argon gas after an ionbom-bardment. The SiO2 film 16 is formed on the first film in a thickness of lambda/4(lambda=400nm) as the second layer by the reactive high frequency ion plating method of an oxygen gas. The vapor-deposited metal titanium film is converted to the titanium dioxide (TiOx 2>=x) film 17 in a thickness of lambda/4(lambda=400nm) by the reactive high frequency ion plating method of the oxygen gas as the third layer. The SiO2 film 18 is formed on the third layer in a thickness of 0.05lambda(lambda=400nm) as the fourth layer by the reactive high frequency ion plating method of the oxygen gas.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to reflective mirror film formation and technology.

[Prior art]

Metal reflective coatings have conventionally been made by vacuum evaporation and are widely used in optical systems such as cameras, copying machines, and semiconductor manufacturing equipment.

FIG. 6 is an enlarged cross-sectional view of such a conventional metal reflective coating.

In FIG. 6, 1 is a substrate made of glass or the like, and 2.degree. 3.4 are thin films sequentially formed on the substrate 1, respectively.

In forming this metal reflective film, first, the substrate 1 is ionized in a low vacuum. After an impardation process (ion cleaning), a metal film 2 of aluminum (At) or copper (Cu) is formed by vacuum evaporation in a high vacuum.

Next, the substrate is heated to 250°C or higher and magnesium fluoride (
A MgF2) film 3 is formed, and a zirconium oxide (Zr02) film or a cerium oxide (CeO2) film 4 is formed thereon to form a three-layered film on the substrate 1.

However, in such film formation, the substrate heating time is inserted between the formation of the metal film 2, MgF2 film 3, ZrO2 or CeO□ film 4 to increase the reflection, so there is a drawback that the time required for film formation is long. there were.

In addition, the hardness of the metal reflective coating formed by this substrate heating method can be determined by using an abrasion resistance reciprocating motion tester (using a probe wrapped in lens wiping paper) and performing 50 reciprocations at a load of 2.5 kg/-. Scratches occurred and the hardness was not satisfactory considering actual use.

[Purpose of the invention]

In view of the problems of the prior art as described above, an object of the present invention is to create a film that does not require high temperatures, maintains the same optical properties as a film formed by a conventional substrate heating method, and is made of a highly adhesive and highly hard metal film. The object of the present invention is to provide an increased reflector.

[Summary of the invention]

According to the present invention, the above-mentioned purpose is achieved by using reactive ion plating, forming a metal reflection-enhancing film only from metal oxide, and adding a thin (S10□) layer of silicon dioxide as the final layer. This is achieved by an enhanced reflection film characterized by adding.

〔Example〕

Hereinafter, specific embodiments of the present invention will be described using the drawings.

FIG. 1 is a schematic diagram of a reactive high frequency ion plating apparatus (hereinafter simply referred to as a film forming apparatus) for forming a metal reflective film of the present invention. The film forming apparatus has a film forming chamber 5, which is connected to a vacuum source (not shown) through an exhaust conduit 6.

A vapor deposition source 7 is arranged at the bottom of the film forming chamber 5, and an evaporation substance 8 is accommodated on the vapor deposition source 7.

As the vapor deposition source 7, an electron beam method is adopted.

A substrate supporting dome 9 is provided near the top of the film forming chamber 5, and a substrate 1 such as a lens is supported and fixed on the dome 9. This substrate support dome 9 is connected to a bias power source 10 outside the film forming chamber 5, so that a negative voltage is applied thereto.

Further, a high frequency coil 11 is provided below the substrate support dome 9.
is arranged, and the coil is connected to a high frequency power source 13 via a matching wire 12 outside the film forming chamber 5.

This film forming apparatus causes a high frequency coil 11 to generate high frequency discharge in a reactive gas introduced through a gas introduction pipe 14, ionizes evaporated molecules from a deposition source 7, and forms a film on a substrate 1 on a substrate support dome 9. This is a device that forms

The gas after each reaction is exhausted to the outside of the film forming chamber through an exhaust conduit 6.

Next, the film formation of the metal enhanced reflection mirror of the present invention will be explained.

When forming a film, first, the degree of vacuum in the film forming chamber 5 is set to I x 10
-'Torr (gas used, argon or oxygen),
High frequency plasma (applied high frequency 13.
56bmz, output 200W), and on the other hand, apply bias voltages eo and skv to the substrate support dome 9 to perform ion gomparding (ion cleaning) and clean the surface on the substrate 1.

1st Embodiment Figure 2 is an enlarged cross-sectional view of a part of the aluminum enhanced reflector of the 1st embodiment. After the ions have been amped up, the degree of vacuum is I x 10 To
rr, and high-frequency ion plating of arganese (Ar) on the first layer (output 100W, vacuum degree 8X10 To
According to (rr), an aluminum (At) film 15 is formed on the substrate. The film thickness at that time was 700X. As a second layer on top of the first layer, reactive high frequency ion plating of oxygen (02) (output 100W, vacuum degree lXl0-'To
A silicon dioxide (SIO2) film 16 is formed by λ rr ). The film thickness at that time is τ (λ=400 nm). A third layer on top of the second layer was reactive high frequency ion plating of oxygen (0□) (output 100W).

The vapor-deposited titanium metal (T1) is transformed into a titanium dioxide (Tiex2〉X) film 17 under a vacuum degree of 2×10 Torr.
Convert to λ. The film thickness at that time is 7 (λ=400 nm). A fourth layer on top of the third layer was reactive high frequency ion plating of oxygen (02) (output 100W).

A silicon dioxide (Sin2) film 18 is formed under a vacuum degree of I.times.10 Torr. The film thickness at that time is
O, OSλ (λ=400 nm).

Figure 3 shows the spectral reflectance characteristics of the aluminum enhanced reflector thus obtained, where the horizontal axis represents the wavelength λ (nm).

The vertical axis indicates the reflectance R (%). As can be seen from the figure, the reflector has a high reflectance in the visible wavelength range.

Second Embodiment FIG. 4 is an enlarged sectional view of a part of the copper-enhanced reflector of the second embodiment.

When forming a film in this embodiment, first, the substrate 1 is subjected to 7-bird treatment (ion cleaning) with ions. The ion mending conditions are the same as in the first embodiment.

After completing the ion derivation, the vacuum level is set to 1X10 Torr.
The first layer was argon (Ar) high frequency ion plating (output 100W, vacuum degree 8X10 To
A copper (Cu 2 ) film 19 is formed on the substrate 1 by the following steps.

The film thickness at that time was 8001 mm. A film of silicon dioxide (sto2) [20] is formed as a second layer on the first layer by reactive high frequency ion plating of oxygen (0□) (output 100 W, vacuum [1×10 Torr). The film thickness at that time is 0.33λ (λ=400 nm). As a third layer on top of the second layer, reactive high frequency ion plating of oxygen (0□) (output 100W, vacuum degree 8X10
Torr), zirconium oxide (Zr02)
A film 21 is formed. The film thickness at that time was 0.55λ (λ
= 400 nm). A fourth layer on top of the third layer was reactive high frequency ion plating of oxygen (02) (output 100W).

A silicon dioxide (8102) film 22 is formed under a vacuum degree of I x 10-'Torr. At that time, the film thickness is 0
．． 05λ (λ=400nm).

FIG. 5 shows the spectral reflectance characteristics of the copper enhanced reflector thus obtained, and as can be seen from the figure, the enhanced reflectance mirror has a high reflectance in the near-infrared wavelength region. In the second example, as the third layer, reactive high frequency ion plating of oxygen (02) (output 100 W, degree of vacuum 2 x 1
Metallic titanium (Ti) deposited by 0-'Torr)
Even when it was converted to titanium dioxide (TiO2), there was no change in the optical properties such as the spectral reflectance characteristics mentioned above and the strength test described below.

In order to investigate the strength of the two metal enhanced reflectors made using the reactive ion derating of the present invention as described above, three tests were conducted: an adhesion test, an abrasion resistance test, and an environmental resistance test. Ta.

The contents of each test are as shown below.

1) Adhesion test; cellophane f on the surface of the above reflector
After adhering the evaporated film to the surface, a quick wiping test is repeated 50 times at an angle almost perpendicular to the surface to see if the deposited film peels off.

2) Abrasion resistance test: The surface of the above reflector was wiped with lens wiping paper (
Using a reciprocating abrasion tester, rub the measuring tip wrapped in Silden paper 50 times at a pressure of 4/d to see if any abnormalities occur.

3) Environmental resistance test: The film-forming substrate of the above reflector was heated to 45°C.
, leave it in a constant temperature and humidity chamber with a relative humidity of 95% for 1000 hours, and check whether any abnormalities occur.

The results of these three tests showed that no abnormalities were observed in any of the tests, and it was found that the film formed by the method of the present invention was extremely strong compared to the film formed by the conventional high-temperature film forming method.

〔Effect of the invention〕

As explained in detail above, the reflection-enhancing film of the present invention is cheaper than conventional reflection-enhancing films because it does not require heating the substrate above 250°C, and has high reflectance, high adhesion, and high hardness. There are certain advantages.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a reactive ion plating apparatus for forming the reflective film of the present invention. FIGS. 2 and 4 are enlarged cross-sectional views of the reflection enhancing films of the present invention, and FIGS. 3 and 5 show their spectral reflectance characteristics. FIG. 6 is an enlarged sectional view of a conventional reflection increasing film. Agent Patent Attorney Ms. Yamashita Figure 2 Figure 3 λ (nm) Figure 4

Claims (1)

[Claims] (1) Provide a first layer of Al or Cu film with a mechanical thickness of 650 to 1000 Å formed by ion plating in Ar on the substrate, and reactive ion plating in O_2 on the first layer. Optical film thickness 0
．． A second layer of SiO_2 film with a thickness of 25λ (λ = 400-550 nm) is provided, and an optical film thickness of 0.25λ is deposited on the second layer by reactive ion plating in O_2.
TiOx (
x≦2) film, or a third layer of a ZrO_2 film, or a CeO_2 film, and an optical film thickness of 0.04λ ~ formed by reactive ion plating in O_2 on the third layer.
An increased reflection film characterized by providing a fourth layer of SiO_2 film with a thickness of 0.06λ (λ=400 to 450 nm).