JP2002339084A - Metal film and metal film coated member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dense metal film, a metal film-coated member, and an optical film, which are single crystal materials having extremely small surface roughness and extremely excellent crystal orientation, and excellent in optical characteristics. It is to provide. SOLUTION: A metal film having a surface having an arithmetic average roughness of 2 nm or less and a (111) peak intensity by X-ray diffraction of 20 times or more of the sum of other peak intensities, and a metal film comprising It is a formed metal film covering member.
The optical coating is made of the metal film, and the difference between the theoretical value of the reflectance in the visible light region and the theoretical value of the pure metal is within 0.2%,
When the incident angle of light is in the range of 10 to 50 °, the amount of change in reflectance is 0.5% or less, or the light wavelength is 250 to 400 n.
The difference between the reflectance at m and the theoretical value for pure metal is 0.2%
Within the range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel metal film, a metal film-coated member, and an optical film using the same.

[0002]

2. Description of the Related Art Conventionally, various substrates have been coated with metal films for the purpose of decoration, improvement of electrical characteristics, use in the optical field, and the like. Depending on the purpose, these metal films utilize the physical properties inherent to the metal itself, such as texture such as gloss and color, electrical properties, and optical properties. Is expected to be stable without being damaged for many years. In particular, in the case of a metal film used for an optical application such as a reflecting mirror represented by silver or aluminum, characteristics such as reflectance, spectral characteristics, and durability are important issues. For example, in a reflector or a light tunnel for a liquid crystal projector, a metal film such as a silver film is formed as a mirror film on the surface of a glass substrate. However, since the optical system of the liquid crystal projector uses many reflecting mirrors, it is necessary to minimize the amount of light lost on the reflecting surface. Further, in the reflection of light rays, if the spectrum is uneven, it directly affects the color unevenness of the projected image. Therefore, a flat reflection characteristic is required in a wavelength region to be used. At this time, the angle at which the light beam enters the reflecting surface is 10 °.
Since the angle is in the range of ５０50 °, the change in the reflection characteristics due to the angle change must be minimized.

On the other hand, a metal film such as a silver thin film formed by vacuum evaporation is extremely poor in environmental resistance. If left in the air after evaporation, an oxide film is formed on the surface in about 24 hours, and the surface becomes cloudy. In the worst case, it is blackened and peeled. If the metal film does not have sufficient adhesiveness to the substrate, moisture permeates the interface with the substrate, causing corrosion.

As a thin film forming method for forming a metal film on the surface of a substrate such as glass, an ion plating method is often employed. In this method, atoms evaporated from a heated evaporation source are partially ionized under reduced pressure by glow discharge or plasma from a high-frequency antenna, and a metal film is deposited on a substrate to which a negative bias voltage is applied. Further, a metal film is also manufactured by a so-called resistance heating type vacuum deposition method in which an evaporation source is heated and vaporized by resistance heating and adhered to a substrate surface in vacuum.

However, since the metal film obtained by these methods has a rough surface and poor crystal orientation, it has been difficult to obtain the high reflection characteristics as described above. Further, as described above, there is a problem that clouding occurs due to oxidation of the surface of the metal film and adhesion to the substrate is poor.

Further, in the conventional method, since the base material cannot be maintained at a desired low temperature state, materials that can be used as the base material are limited.

[0007]

SUMMARY OF THE INVENTION It is a main object of the present invention to provide a single-crystal metal film and a metal film-coated member having very small surface roughness and excellent crystal orientation. . Another object of the present invention is to provide a metal film and a metal film-coated member that can be formed on the surface of a substrate having a low heat-resistant temperature and have excellent adhesion to the substrate. Still another object of the present invention is to provide an optical coating having excellent optical properties.

[0008]

The inventors of the present invention have conducted intensive studies to provide a method for forming a thin film having excellent adhesion to a substrate. Connecting a boat holding the thin film material (evaporation material) in the chamber to the anode side of a DC voltage application power source; b. Leaving the chamber floating without being electrically grounded; and c. By controlling the gas supply amount of Ar gas or the like for generating plasma so that the subsequent period is smaller than the initial period of the thin film formation for forming the thin film, (1)
Since high-frequency discharge does not occur between the substrate holding member and the chamber, and charged particles in the plasma in the chamber are not attracted to the inner wall of the chamber, ionized particles or positively charged particles in the plasma Is efficiently guided to the surface of the substrate, and the electrons in the plasma are intensively guided to the evaporation material on the boat, (2)
When the plasma is stabilized, the evaporating material evaporates so that the evaporating material is absorbed by the plasma by irradiating the evaporating material with an electron beam, and (3) electrons in the plasma collide with the evaporating material intensively. The evaporating material, which gives energy for evaporation and obtains high energy instead of heat energy, easily evaporates even at low temperatures. As a result, it has been found that the heating energy of the evaporation material due to resistance heating or the like can be remarkably reduced, the temperature rise of the base material due to heat radiation from the evaporation source can be suppressed, and a thin film can be formed at a low temperature. Based on such knowledge, the present applicant has previously filed a patent application for a thin film forming apparatus and a thin film forming method (Japanese Patent Application No. 2001-16711).

However, surprisingly, the present inventors have found that the metal film obtained using such an apparatus and method is dense and has few defects in the film, so that the surface roughness (arithmetic mean roughness) is high. Etc.) were found to be very small (2 nm or less), and a single crystal having extremely good crystal orientation (crystals are aligned in one direction) was obtained. The reason why such a metal film is obtained is not clear, but it is presumed to be due to the fact that the evaporated material is in a high energy state (excited state) by electron irradiation despite its low temperature. . That is, the metal film of the present invention is characterized in that the arithmetic average roughness of the surface is 2 nm or less, and the (111) peak intensity by X-ray diffraction is 20 times or more of the sum of other peak intensities.

The metal film of the present invention has such a structure,
Furthermore, it has the following features. (1) The difference between the reflectance of the pure metal in the visible light region (about 400 to 700 nm) and the theoretical value of the pure metal is extremely small, within 0.2%. (2) When the light incident angle is in the range of 10 to 50 °, the amount of change in reflectance is extremely small at 0.5% or less. (3) The difference between the reflectance of pure metal at a light wavelength of 250 to 400 nm (ultraviolet to blue) and the theoretical value of pure metal is 0.2.
% And extremely small. (4) Excellent adhesion to base material. (5) Even if exposed to the atmosphere, there is no corrosion and durability is dramatically improved. The features (3) to (5) are particularly remarkable in the Ag film.

As the metal film of the present invention, Ag, Cu, A
u, Pt, Al, Ti, Cr, Ni, Fe, W, Zn,
At least one kind of Si is given.

[0012] The metal film-coated member of the present invention is characterized in that the metal film is formed on a substrate. Further, in the present invention, an antireflection film made of a dielectric multilayer film may be formed on the surface of the metal film. Further, the film is not limited to the antireflection film, and may be a reflection increasing film, a protective film, or the like. As the dielectric multilayer film, for example, MgF ₂ , TiO ₂ , Al ₂ O ₃ , Z
rO ₂ , SiO _{2 and the} like.

Examples of the substrate include glass, ceramics, semiconductor materials, metal materials, plastics and the like. Further, the metal film of the present invention is formed by a thin film forming method in which a plasma-converted thin film material is deposited on a surface of a substrate held at 100 ° C. or lower, preferably 80 ° C. or lower, more preferably 60 ° C. or lower. A metal film whose surface has an arithmetic average roughness of 2 nm or less, and whose (111) peak intensity by X-ray diffraction is 2 times the sum of other peak intensities;
It is characterized by being at least 0 times.

Specifically, in the metal film of the present invention, a step of holding a substrate on which a thin film made of metal is to be formed in a chamber, and supplying a gas for generating plasma into the chamber. A step of applying a high-frequency electric field to a space in the chamber; a step of heating and evaporating an evaporation material to be a raw material of a thin film in the chamber; and supplying a gas for generating plasma to the chamber. A gas supply amount control step of controlling the amount to be smaller in the subsequent period than in the initial stage of the thin film formation for forming the thin film on the base material, and during the thin film formation, It is characterized by being formed by a thin film forming method of keeping the temperature at 80 ° C. or lower. This metal film has a surface having an arithmetic average roughness of 2 nm or less, and has an (1)
11) The peak intensity is at least 20 times the sum of the other peak intensities. In the present invention, it is preferable to include a step of applying a DC voltage between the substrate and the boat holding the evaporating material, with the boat side as the anode side. Preferably, the chamber is in an electrically floating state.

The optical coating of the present invention comprises a metal film having an arithmetic average roughness of 2 nm or less on the surface and a (111) peak intensity by X-ray diffraction of 20 times or more of the sum of other peak intensities; The difference between the reflectance of the pure metal in the visible light region and the theoretical value of the pure metal is within 0.2%. In this case, it is preferable that the amount of change in the reflectance be 0.5% or less when the incident angle of light is in the range of 10 to 50 °.

The other optical coating of the present invention has an arithmetic average roughness of 2 nm or less on the surface and has an (11)
1) A metal film having a peak intensity of 20 times or more of the sum of the other peak intensities, and having a light wavelength of 250 to 400 nm
The difference between the reflectance of the pure metal and the theoretical value of the pure metal is within 0.2%. As a metal film used for these optical coatings, for example, silver, aluminum, copper, chromium, etc. are preferable, but they have a flat and high reflection characteristic particularly in a visible light region, and also have a comparative property in a small wavelength region such as a blue region. Silver having extremely high reflection characteristics is preferred.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The arithmetic average roughness of the surface of the metal film of the present invention is 2 nm or less, and the (111) peak intensity by X-ray diffraction is 20 times or more of the sum of other peak intensities. The surface roughness of the metal film can be measured by observation with an atomic force microscope (AFM). With an atomic force microscope, when a cantilever with a probe is brought close to the sample surface, the displacement of the cantilever is detected by laser reflected light using the bending of the cantilever due to the atomic force, and irregularities on the surface are on the order of nanometers. Refers to a microscope that can be imaged with a microscope. The fact that the surface roughness measured by such an atomic force microscope is 2 nm or less means that the surface is substantially flat. Thereby, scattering of light on the film surface, which is a major cause of a decrease in reflectance, is suppressed.

The (111) peak intensity by X-ray diffraction is at least 20 times the sum of the other peak intensities. This means that the crystal orientation is high, the crystal density is high and the density is high, and the properties of the metal film are uniform. As a result, absorption and scattering of light, which is a major cause of a decrease in reflectance, into the film are suppressed. That is,
Light absorption means that light energy is converted into heat and lost in the film, and occurs when a defect such as an impurity exists in the film. Therefore, from the above points, it is considered that the metal film of the present invention is dense and flat, so that scattering and absorption of light are suppressed and high reflectance is realized.

Next, a method for producing the metal film of the present invention will be described. FIG. 1 schematically shows an apparatus used for forming the thin film. An evaporating source 20 that accommodates and holds the evaporating material 9 in the boat 1 is disposed in a lower part of the chamber 11. A base material holding section 2 for holding the base material 10 is provided at an upper portion in the chamber 11 so as to face the evaporation source 20.

The substrate holder 2 is made of a conductive material, and high-frequency power from a high-frequency power supply (RF) 5 is applied via a matching device (MN) 4 and a capacitor 7 as a DC shielding filter. It is supposed to be. The capacitor 7 may function as a part of a matching circuit using a variable capacitor. Further, the cathode side of a DC voltage applying power source (DC) 6 is connected to the base material holding unit 2 via a coil 8 as a high frequency shielding filter. Base material holder 2 of high frequency power supply 5
The terminal on the opposite side is connected to the anode side of the DC voltage applying power source 6, and these are grounded.

The boat 1 itself is made of a material having a high electric resistance, for example, and receives power supplied from a heating power supply 3 composed of, for example, an AC power supply to generate heat for evaporating the evaporation material 9. . The boat 1 is further connected to an anode side of a DC voltage application power supply 6.

The space inside the chamber 11 is
The gas is evacuated by the vacuum pump 14 through the exhaust valve 13, and a predetermined vacuum state is established during the thin film formation period. In order to supply an inert gas (for example, argon gas or the like) into the chamber 11, an inert gas supply source 21 is connected to the chamber 11 via a flow control device (MFC) 24 and a gas supply pipe 25. I have. The supply / stop from the inert gas supply source 21 is performed by opening and closing the valve 21a. The apparatus shown in FIG. 1 uses a reactive gas supply source 2 to supply a reactive gas such as oxygen gas.
Although 3 is attached, this is not used in the present invention.

The degree of vacuum in the chamber 11 is measured by a vacuum
And based on the output of the vacuum gauge 15,
The flow control device 24 is controlled by a control device 30 including a microcomputer or the like. Thereby, the gas supply amount from the inert gas supply source 21 is
The degree of vacuum in the chamber 11 is controlled to be maintained at a predetermined value. In order to obtain the metal film of the present invention, the chamber 1
The degree of vacuum in 1 is 1.0 × 10 ^{−2 to} 5.0 × 10 ⁻² Pa,
Preferably good is a ^{2.5 × 10 -2 ~3.5 × 10 -2} Pa.

In order to measure the formation rate of the thin film on the surface of the substrate 10, the film thickness monitor 1
7 are provided. The output signal of the film thickness monitor 17 is input to the control device 30, and the control device 30
Controls the output of the heating power supply 3 based on the output of the film thickness monitor 17. In this way, the amount of power to the boat 1 is controlled and the amount of evaporation of the evaporation material 9 is adjusted so that the thin film formation speed becomes a desired value. In order to obtain the metal film of the present invention, the formation rate of the metal film is 10 to 20.
Å / sec, preferably 15-18 Å / sec.

The high frequency power supply 5 has a frequency 1
A high-frequency power supply of 0 to 50 MHz may be used, but a general 13.
The output may be set to 50 MHz to 800 m per unit area (cm ² ) of the base material holding part 2 as a discharge electrode.
A high frequency power of W, preferably 85 to 170 mW, is applied to the base material holding unit 2. A high-frequency electric field corresponding to this is formed in the chamber 11, so that the gas supplied from the gas supply pipe 25 and the evaporation material 9
A plasma consisting of the evaporant evaporated from the gas is generated. Positively charged particles of the ionized particles in the plasma are attracted to the surface of the substrate 10 by the DC bias applied to the substrate holding unit 2 from the DC voltage application power supply 6. The applied voltage from the DC voltage applying power source 6 is 100 to 400 V, preferably 180 to 230 V.

On the other hand, the dissociated electrons in the plasma are drawn to the boat 1 connected to the anode side of the DC voltage applying power source 6. At this time, since the evaporating material 9 is continuously evaporating from the evaporating source 20, the luminous body having a shape such that the foot of the plasma descends to the evaporating source 20 due to the collision between the evaporating particles and the electrons is generated. In the vicinity. Then, the electrons collected near the evaporation source 20 are sucked into the boat 1 connected to the anode side, which is grounded, and collides with the evaporation material 9 on the boat 1. Thereby, the evaporation material 9
Is evaporated by the heating by the boat 1 and the collision of electrons. That is, an effect of promoting evaporation at a low temperature by intensive electron collision with the evaporation material 9 (deposition assist effect) is obtained.

As shown in FIG. 1, the chamber 11
Is not connected to any of the DC voltage application power supply 6 and the high frequency power supply power supply 5 and is not grounded. That is, the chamber 11 is in an electrically floating state. Therefore, high-frequency discharge does not occur between the substrate holding unit 2 and the chamber 11, and charged particles in the plasma in the chamber 11 are not attracted to the inner wall of the chamber 11. Therefore, the cationized particles or the positively charged particles in the plasma are efficiently guided to the surface of the substrate 10, and the electrons, which are the negatively charged particles in the plasma, are transferred to the evaporation material 9 on the boat 1. Will be led intensively. Thereby, a good thin film can be formed, and the evaporation of the evaporation material 9 by the electron beam can be efficiently promoted. Further, it is possible to suppress the evaporation material from adhering to the inner wall of the chamber 11.

When the plasma is stabilized in the chamber 11, the evaporating material 9 evaporates so that the evaporating material 9 is absorbed by the plasma by irradiating the electron beam with the plasma. Therefore, in order to keep the deposition rate of the evaporation material 9 attached to the base material 10 constant, the control device 30 lowers the output of the heating power supply 3 based on the output of the film thickness monitor 17.
That is, the current or voltage applied to the boat 1 is reduced. Thereby, the evaporation rate is adjusted.

Since the evaporation of the evaporation material 9 is accelerated by the electron beam supplied from the plasma, the heating current value of the boat 1 can be kept low. Therefore, the evaporation of the evaporation material 9 is continued at a relatively low heating temperature. Can be maintained
A thin film can be formed by vapor deposition utilizing the action of plasma.

The feature of the thin film formation in this embodiment is as follows.
The method is to supply the inert gas to the chamber 11. That is, in this embodiment, in the initial stage of thin film formation, gas is supplied from the gas supply pipe 25 to the chamber 11 at a relatively large flow rate, and when evaporation from the evaporation material 9 becomes active, The gas supply amount is reduced, so that an inert gas plasma supplied from the gas supply pipe 25 is formed in the chamber 11 in an initial stage of thin film formation in which evaporation from the evaporation material 9 is not active. When the evaporation from the evaporation material 9 becomes active, the gas supply amount from the gas supply pipe 25 decreases, and a plasma having a composition in which the evaporation particles from the evaporation material 9 become dominant is formed in the chamber 11. .

As described above, by introducing the inert gas into the chamber 11 at the initial stage of thin film formation, stable plasma can be quickly formed in the chamber 11. Thus, a thin film can be formed from the initial stage by utilizing the action of the plasma, so that a thin film having good adhesion can be formed on the surface of the substrate 10.

FIG. 2 is a diagram for explaining a more specific process of forming a thin film. FIG. 2 shows that when the metal film is formed on the surface of the substrate 10,
An example of a process for forming a thin film while supplying an inert gas into the chamber 11 from the above is described. Specifically, FIG. 2A shows a change over time of the gas supply amount, and FIG.
Fig. 2 (c) shows the time change of the degree of vacuum in the chamber 11;
Represents the time change of the heating current value of the boat 1.

In the period T1 before the start of the thin film forming process, the control device 30 opens the exhaust valve 13 and sets the vacuum pump 14
As a result, the atmosphere in the chamber 11 is exhausted, and the degree of vacuum in the chamber 11 is maintained at, for example, about 10 ⁻³ Pa. From this state, the control device 30 opens the valve 21a at time t10 to start supplying the gas from the inert gas supply source 21. After this gas supply is started, the control device 3
0 sets the degree of vacuum in the chamber 11 to, for example, 2 × 10 ⁻² Pa by monitoring the output signal of the vacuum gauge 15.
The flow control device 24 is controlled so as to hold the pressure.

Thus, during the period T2 in which the energization of the boat 1 is started and the evaporating material 9 is heated, plasma is generated in the chamber 11 by the high-frequency electric field applied from the high-frequency power supply 5. The atoms and molecules of the ionized inert gas in the plasma are guided to the substrate 10 by the DC bias applied to the substrate holding unit 2 from the DC voltage application power supply 6. When the atoms and molecules of the inert gas collide with the base material 10, the period T2
If an undesired increase in the temperature of the substrate 10 occurs therein, a shutter 18 may be provided below the substrate 10 to block the inert gas flowing toward the substrate 10.

During the period T2, the control device 30
To start energizing the boat 1. Along with this, the heating current value to the boat 1 increases, and reaches, for example, 150 A at the end of the period T2. Chamber 1
At time t11 when the plasma in 1 is stabilized,
The shutter 18 is opened by a driving device (not shown) under the control of the control device 30, thereby starting the formation of the thin film. The evaporation of the evaporation material 9 leads to the evaporation particles being introduced into the plasma. Therefore, if the gas is supplied from the gas supply pipe 25 into the chamber 11 at a constant flow rate,
The degree of vacuum in the chamber 11 decreases.

However, the control device 30 controls the chamber 11
The flow rate control device 24 is controlled so that the degree of vacuum in the inside is maintained at a constant value (for example, 2 × 10 ⁻² Pa), and the gas supply amount via the gas supply pipe 25 is adjusted. As a result, as the amount of evaporation from the evaporation material 9 increases, the amount of the inert gas introduced into the chamber 11 decreases as indicated by reference numeral A. Therefore, at the beginning of the period T3 during which the thin film is formed, the composition of the plasma is dominated by the inert gas, but the composition of the plasma is quickly changed by the evaporant of the evaporation material 9. It changes to.

On the other hand, the supply of electrons from the plasma promotes evaporation from the evaporating material 9, and the current supplied from the heating power supply 3 to the boat 1 is referred to by feedback control based on the output of the film thickness monitor 17. It will decrease as shown by the symbol B. For example, after a period of about 2 to 3 seconds, the current value decreases from 150 A to 80 A.
For this reason, the evaporation material 9 evaporates at a lower temperature than in normal vapor deposition or ion plating, and the radiant heat from the evaporation source 20 causes the base material 1 to evaporate.
0 does not rise excessively.

As described above, according to this embodiment, the thin film formation is started in a state in which the inert gas is introduced into the chamber 11, so that the chamber 1 can be formed from the initial stage of the thin film formation.
1, a good plasma can be generated. Thereby, the evaporating material is efficiently guided to the base material 10 while receiving the action of the plasma from the initial stage. As a result, a metal film having good adhesion can be efficiently formed on the surface of the substrate 10.

In this metal film forming method, the base material 10
0 ° C. or lower, preferably 80 ° C. or lower, more preferably 60 ° C.
Since the temperature is maintained at a temperature of not more than ° C., it is suitable for forming a metal film on a base material such as glass, ceramics, semiconductor material, metal material or plastic, or a base material 10 such as resin film. For example, the heat-resistant temperature of polycarbonate is 120
~ 130 ° C, heat resistance temperature of polymethyl methacrylate is 80
Since the temperature is on the order of ° C., a metal film can be formed on these substrates 10.

FIG. 3 shows another example of the thin film forming apparatus used in the present invention. In the figure, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. The apparatus includes a feeding roller 31 having a belt-like film base material 10A (eg, a resin film) wound in a chamber 11 and a film base material 10A fed from the feeding roller 31.
And a high-frequency shaft electrode 2 serving as a base material holding portion between the winding roller 32 and the winding roller 32 for winding the substrate.
A is arranged. Auxiliary shafts 33 and 34 are arranged on both sides of the high-frequency shaft electrode 2A.

The high-frequency shaft electrode 2A is made of a round rod-shaped conductive member, and receives high-frequency power from a high-frequency power supply 5 and a DC bias from a DC voltage application power supply 6. Below the feed-out roller 31 and the take-up roller 32, a deposition-preventing plate 35 having an opening 35a for exposing the film substrate 10A on the lower surface side of the high-frequency shaft electrode 2A is arranged. In addition, a coating material supply device 3 for supplying an evaporation material to the boat 1 in relation to the evaporation source 20.
6 are arranged.

With this configuration, the take-up roller 3
2, the metal film can be continuously formed on the surface of the film substrate 10A fed from the feeding roller 31 while winding the film substrate 10A. Others are the same as those shown in FIGS.

As described above, according to the metal film forming method, the gas for forming the plasma is supplied into the chamber 11, so that the plasma can be quickly generated in the chamber 11 at an early stage of the thin film formation. . Thus, from the initial stage of thin film formation, it is possible to produce a metal film utilizing the action of plasma, and it is possible to obtain a metal film having excellent adhesion to the substrate 10. Also, the chamber 11
In order to supply a large amount of gas into the inside of the thin film at the beginning of the formation of the thin film, and to reduce the amount after that, the atoms and molecules of the inert gas supplied into the chamber 11 collide with the substrate 10.
Temperature rise can be suppressed.

Further, due to the DC electric field applied from the DC applied voltage power supply 6, the positively charged particles or cationized particles in the plasma are accelerated in the direction of the substrate 10 and fly and collide with the substrate 10. Then, it is deposited on the surface of the substrate 10. As a result, a film is formed.
On the other hand, electrons having a negative charge are accelerated toward the boat 1 on the anode side and intensively collide with the evaporation material 9 on the boat 1 to give the evaporation material 9 energy for evaporation.
Thus, the evaporating material 9 that has obtained high energy instead of heat energy easily evaporates even at a low temperature, and
It evaporates to the plasma formation region inside. That is, the electrons in the plasma formed in the chamber 11 are guided to the evaporating material 9, thereby promoting the evaporation of the material, that is, a so-called deposition assist effect is obtained. Energy can be significantly reduced. As a result, a rise in the temperature of the substrate 10 can be suppressed, so that a thin film can be formed at a lower temperature.

The thickness of the metal film of the present invention is about 500 to 150.
0 °, preferably 800-1100 °. The metal film having such a thickness can be formed in about 5 to 10 minutes. During this time, the temperature of the surface of the substrate 10 does not exceed 100 ° C. Further, the amount of evaporation from the evaporation material 9 is adjusted by controlling the energy applied to the heating means and the output of the DC voltage application power supply 6 within the above-mentioned range.
The collision energy of the particles of the evaporating material 9 against the substrate 10 is adjusted by controlling the output of the DC voltage applying power source 6 within the above range. As a result, in the deposition material,
Rather than merely depositing on the surface of the substrate 10, sufficient energy can be given to rearrange the atomic or molecular arrangement of the deposition material layer formed on the surface of the substrate 10 to a stable state. Further, sufficient energy can be applied to the particles of the deposition material to penetrate into the substrate 10 and adapt.

For this reason, in the present invention, a dense and excellent adhesion film is obtained, which is flat and almost free from defects in the film, and a metal film close to a single crystal layer of almost pure metal can be obtained.

The metal film of the present invention can be suitably used for various applications as exemplified below by utilizing its excellent properties.

(1) When the base material 10 is glass, for example, a reflection mirror and a light tunnel for a liquid crystal projector having an Ag film formed as a mirror film, an infrared reflector having an Au film formed as a reflection film, a reflection film Optical measuring instruments such as a light meter and a laser interferometer having an Al film without a protective film formed thereon. (2) When the base material 10 is ceramics, A
u, Cu, Al, Ag, Pt, Ti, Cr, Ni, W,
A ceramic wiring board on which at least one of Fe is formed, a substrate for mounting a semiconductor element, a member of a container for storing a semiconductor element, and the like; (3) When the base material 10 is a semiconductor material, an infrared anti-reflection member or the like in which ZnS, Si, and ZnS are sequentially formed on the base material 10 made of Si, Ge, or the like. (4) When the base material 10 is plastic, the irregularly shaped base material 10 on the surface of which the predetermined irregularities are formed by molding is used as a reflection film.
High-reflection mirrors coated with 1, Ag, etc. (5) When the substrate 10 is a resin film, a thin-film resistor or the like formed with Ti, Al, or the like, a solar cell or a thin-film capacitor formed with a Si film. (6) When the base material 10 is a metal material, a condenser mirror of an infrared lamp in which an Au film or the like is formed on the Al base material 10 as a reflection film. (7) In addition, a metal film-coated member in which a metal oxide film and a fluoride film are sequentially laminated on the metal film of the present invention in order to prevent the deterioration of the metal film.

In particular, the metal film of the present invention has an excellent optical property that the difference in reflectance in the visible light region from the theoretical value of a pure metal is within 0.2%. Most suitable for use as an optical coating such as a reflection film or an antireflection film.

[0050]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited to only the following Examples.

Example 1 Using the thin film forming apparatus shown in FIG. 1, a silver film was produced by the process shown in FIG. The manufacturing conditions are shown below. Substrate 10: 3 mm-thick glass plate Evaporation material 9: Silver Introduced gas into chamber 11: Argon gas Applied power to substrate holding unit 2 from high-frequency power supply 5: 85 mW / cm at a frequency of 13.56 MHz ² (applied power per unit area of base material holding unit 2) DC applied power source 6: Connect cathode side to base material holding unit 2 and connect anode side to boat 1 DC applied power source 6 to base material holding unit 2 Applied voltage: 230 V Chamber 11: not grounded, in an electrically floating state Metal film formation speed: 18 ° / sec (a) Initial stage of metal film formation (period T2 in FIG. 2) Degree of vacuum in chamber 11 : Constant at 2 × 10 ^-2 Pa Current flowing from the heating power source 3 to the boat 1: 280 A (T2
(End stage) (b) Metal film formation stage (period T3 in FIG. 2) Degree of vacuum in chamber 11: constant at 2 × 10 ⁻² Pa Current flowing from heating power supply 3 to boat 1: 210 A (T3)
The final stage) Thus, a silver film having a thickness of 1500 ° could be formed on the surface of the substrate 10. The surface temperature of the substrate 10 was maintained at about 40 to 45 ° C. throughout the entire period of the production of the silver thin film due to slight reaction of the thermoseal reacting at 40 ° C.

COMPARATIVE EXAMPLE 1 Using a normal ion plating apparatus shown in FIG. 4, a surface of a base material 53 (a glass plate having a thickness of 3 mm) having a thickness of 1500
銀 A silver film was prepared. This device generates plasma near an antenna 51 connected to a high-frequency power supply 50 (applied power has a frequency of 13.5).
400 W at 6 MHz). Argon gas is introduced into the chamber 52, and the degree of vacuum is set to 2 × 10 ⁻² Pa. The substrate 53 and the chamber 52 are grounded at the same potential, and a silver film is formed on the surface of the substrate 53 by self-bias. Silver as the evaporation material 54 is evaporated by the electron beam irradiation of the electron gun 55.

COMPARATIVE EXAMPLE 2 Using a normal resistance heating type vacuum deposition apparatus shown in FIG.
A silver film of 0 ° was formed. This device has a vacuum degree of 2 × 10
Evaporating material 64 in the chamber 62 set to ^-2 Pa
(Silver) is heated and vaporized by a heating current of 320 A from an AC power supply 65, and is vapor-deposited on the base material 63.

The following evaluation tests were performed on the silver films obtained in Example 1 and Comparative Examples 1 and 2.

1. Surface Roughness of Silver Film The surface state of the prepared silver film having a thickness of about 1500 ° is measured by an atomic force microscope (AFM, N Instruments manufactured by Digital Instruments).
The surface roughness of the film was imaged on the order of nanometer, and the arithmetic average roughness (Ra) was examined. As a result, the silver film of Example 1 had a thickness of 2 nm.
On the other hand, the silver films of Comparative Examples 1 and 2 each had a thickness of about 3 to 5 nm.

2. (111) peak intensity by X-ray diffraction X-ray diffractometer (RINT1400V type manufactured by Rigaku Denki)
X-ray output 50kV-200mA, measurement range 2θ
= 10 ° to 100 °, measurement was performed at an emission slit-scattering slit-receiving slit: 1 ° -1 ° -0.3 mm. As a result, in the silver film of the example, the (111) peak intensity was at least 20 times the sum of the other peak intensities. In contrast, the silver films of Comparative Examples 1 and 2 were 2 to 15 times.

3. Reflectivity (1) Measurement of reflectance in the visible light range The reflectance in the visible light range (about 400 to 700 nm) was measured by a photometer (Spectrophotometer U-4000 manufactured by Hitachi, Ltd.). Measured. As a result, the difference between the reflectance of the silver film of the example and the theoretical value of the pure metal was within 0.2%. In contrast, the silver films of Comparative Examples 1 and 2 were both within 2%. The theoretical values are based on the chart of basic physical properties (Kyoritsu Publisher,
It was determined from the refractive index of pure silver described in May 128, 1972, pages 128 to 131 (silver). (2) Amount of Change in Reflectance Amount of change in reflectance was measured by the same photometer as in the above (1) when the incident angle of light was in the range of 10 to 50 °. as a result,
In the silver film of the example, the variation of the reflectance was within 0.5%. On the other hand, the silver films of Comparative Examples 1 and 2 were both 5% or more. (3) Reflectance at a light wavelength of 250 to 400 nm The reflectance at a light wavelength of 250 to 400 nm was measured by the same photometer as in (1) above. As a result, in the silver film of the example, the difference from the theoretical value of the pure metal was within 0.5%. On the other hand, the silver films of Comparative Examples 1 and 2 both
15%. The theoretical value is the reflectivity of pure silver described in the above basic physical property chart.

4. Environmental resistance According to MIL-M-13508, temperature 50 ° C, humidity 95
%, The surface of the silver film was observed. As a result, no turbidity occurred on the surface of the silver film of the example, but opacity occurred on the silver films of Comparative Examples 1 and 2. 5. Adhesion Adhesion was examined by performing a tape test described in MIL-M-13508. As a result, the silver film of the example did not peel off, but the silver films of comparative examples 1 and 2 were easily peeled off.

Test Example 1 (Preparation of Aluminum Film) On the surface of each substrate 10 of glass (G), polycarbonate (PC) and polymethyl methacrylate (PM), the method (A) of Comparative Example 1 and the method of Comparative Example 2 were applied. Using the method (B) and the method (C) of Example 1, an Al film having a thickness of about 1100 ° was formed. The preparation conditions of each sample are as follows. A: Using aluminum instead of silver as the evaporating material,
A conventional ion-plated product obtained in the same manner as in Comparative Example 1 except that the high-frequency output was changed from 400 W to 380 W. B: Using aluminum instead of silver as the evaporating material,
A conventional resistance heating product obtained in the same manner as in Comparative Example 2, except that the film formation rate was changed from 18 ° / sec to 15 ° / sec. C: using aluminum instead of silver as the evaporation material,
High frequency output and thin film formation speed of 85 mW / c each
m ² and 18 ° / sec to 80 mW / cm ² and 15 °
The product of the present invention obtained in the same manner as in Example 1 except that the rate was changed to / sec. (1) The surface roughness of each obtained sample was measured by the method described above. The result is shown in FIG. For example, if the sample name is G-AL-A, the glass (G) substrate 1
0 shows that an aluminum (AL) film was formed on the surface of Comparative Example 1 by the method (A) of Comparative Example 1. (2) The measurement results of the reflectance of each sample are shown in FIGS. (3) FIGS. 10 to 12 show the results of X-ray diffraction measurement of each Al film obtained by using the method (C) of Example 1, the method (A) of Comparative Example 1, and the method (B) of Comparative Example 2. Show.

Test Example 2 (Preparation of Copper Film) In the same manner as in Test Example 1, glass (G)
On the surface of each substrate 10 of polycarbonate (PC) and polymethyl methacrylate (PM), the method (C) of Example 1,
Using the method (A) of Comparative Example 1 and the method (B) of Comparative Example 2, a Cu film having a thickness of about 1300 ° was formed. The preparation conditions of each sample are as follows. A: Copper was used instead of silver as the evaporating material, and the high-frequency output and the thin film formation speed were 400 W and 18 ° /
Comparative Example 1 except that the power was changed from 420 seconds to 420 W and 12 ° / second.
A conventional ion-plated product obtained in the same manner as above. B: Conventional resistance heating product obtained in the same manner as in Comparative Example 2 except that copper was used instead of silver as the evaporating material, and the thin film formation rate was changed from 18 ° / sec to 12 ° / sec. C: The same as Example 1 except that copper was used instead of silver as the evaporating material, and the high-frequency output and the thin film formation rate were changed from 85 mW / cm ² and 18 ° / sec to 88 mW / cm ² and 12 ° / sec, respectively. The product of the present invention obtained by: (1) The surface roughness of each obtained sample was measured by the method described above. The result is shown in FIG. Note that the sample name, for example, G-Cu-A indicates that a copper (Cu) film was formed on the surface of the glass (G) substrate 10 by the method (A) of Comparative Example 1. (2) The measurement results of the reflectance of each sample are shown in FIGS. (3) For the same graph as FIG.
FIG. 17 shows reflectance characteristics in the range of nm. The literature values shown in the figure are the 422 to 42 of the basic physical property chart described above.
The values described on page 9 (copper) are shown.

[0061]

The metal film of the present invention has a very small surface roughness, is single-crystal having a very good crystal orientation, and has excellent optical characteristics. Further, the metal film of the present invention can be formed on the surface of a substrate having a low heat-resistant temperature, and has an effect of having excellent adhesion to the substrate.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing an example of a thin film forming apparatus for manufacturing a metal film of the present invention.

FIG. 2 is an explanatory diagram showing a process of forming a thin film.

FIG. 3 is a conceptual diagram showing another example of the thin film forming apparatus.

FIG. 4 is a schematic diagram showing a normal ion plating apparatus used for forming a metal film in Comparative Example 1.

FIG. 5 is a schematic diagram showing a resistance heating type vacuum deposition apparatus used for forming a metal film in Comparative Example 2.

FIG. 6 is a graph showing the relationship between the deposition method and the surface roughness for each Al film obtained in Test Example 1.

FIG. 7 is a graph showing the reflectance of each Al film / glass substrate obtained in Test Example 1.

FIG. 8 is a graph showing the reflectance of each Al film / polycarbonate substrate obtained in Test Example 1.

FIG. 9 is a graph showing the reflectance of each Al film / polymethyl methacrylate substrate obtained in Test Example 1.

FIG. 10 is a graph showing an X-ray diffraction measurement result of an Al film (product C of the present invention) obtained by using the method of Example 1 in Test Example 1.

11 is a graph showing an X-ray diffraction measurement result of an Al film (conventional ion-plated product A) obtained by using the method of Comparative Example 1 in Test Example 1. FIG.

12 is a graph showing an X-ray diffraction measurement result of an Al film (conventional resistance heating product B) obtained by using the method of Comparative Example 2 in Test Example 1. FIG.

FIG. 13 is a graph showing the relationship between the vapor deposition method and the surface roughness of each Cu film obtained in Test Example 2.

FIG. 14 is a graph showing the reflectance of each Cu film / glass substrate obtained in Test Example 2.

FIG. 15 is a graph showing the reflectance of each Cu film / polycarbonate substrate obtained in Test Example 2.

FIG. 16 is a graph showing the reflectivity of each Cu film / polymethyl methacrylate substrate obtained in Test Example 2.

FIG. 17 is a graph showing reflectance characteristics in the same graph as FIG. 14 in Test Example 2 in the range of light wavelengths from 250 to 700 nm.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Boat 3 Heating power supply 4 Matching device 5 High frequency power supply power supply 6 DC voltage application power supply 9 Evaporation material 10 Substrate 11 Chamber 20 Evaporation source

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[Procedure amendment]

[Submission date] February 27, 2002 (2002.2.2)
7)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] FIG.

[Correction method] Change

[Correction contents]

FIG. 13

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) C23C 24/08 C23C 24/08 B 4K044 G02B 1/11 G02B 5/08 C 5/08 G02F 1/1333 500 G02F 1/1333 500 1/1335 520 1/1335 520 G02B 1/10 A F-term (reference) 2H042 DA01 DA02 DA03 DA04 DA05 DA06 DA07 DA10 DA11 DA12 DA18 DA21 DC02 DE04 2H090 JB02 JB03 JB04 LA20 2H091 FA14Z FA37X FC02 GA16 LA30 MA07 2K009 AA02 BB01 BB02 BB06 BB11 CC03 CC06 4K029 AA02 AA04 AA06 AA09 AA11 AA24 BA01 BA03 BA04 BA05 BA07 BA08 BA09 BA12 BA13 BA17 BA18 BA35 BB02 BB07 BC07 BD09 CA03 CA04 DD01 DD02 EA08 4K04AA AB13

Claims (22)

[Claims] An arithmetic average roughness of a surface is 2 nm or less,
A metal film, wherein the (111) peak intensity by X-ray diffraction is at least 20 times the sum of the other peak intensities. 2. The metal film according to claim 1, wherein the difference between the reflectance in the visible light region and the theoretical value of the pure metal is within 0.2%. 3. The metal film according to claim 2, wherein the amount of change in reflectance is 0.5% or less when the incident angle of light is in the range of 10 to 50 °. 4. The metal film according to claim 1, wherein the difference between the reflectance at a light wavelength of 250 to 400 nm and the theoretical value of the pure metal is within 0.2%. 5. Ag, Cu, Au, Pt, Al, Ti, C
The metal film according to claim 1, wherein the metal film is at least one of r, Ni, Fe, W, Zn, and Si. 6. A member coated with a metal film, wherein the metal film according to claim 1 is formed on a substrate. 7. An anti-reflection film made of a dielectric multilayer film is formed on a surface of said metal film.
The metal film-coated member according to any one of the preceding claims. 8. The metal film-coated member according to claim 6, wherein said substrate is made of glass, ceramics, semiconductor material, metal material or plastic. 9. A metal film formed by a method of forming a thin film on a surface of a substrate held at a temperature of 100 ° C. or lower, wherein the arithmetic average roughness of the surface is 2 nm or less. A metal film having a (111) peak intensity by X-ray diffraction of 20 times or more of a total of other peak intensities. 10. The metal film according to claim 9, wherein said substrate is formed at a temperature of 80 ° C. or lower. 11. The difference between the reflectance of the pure metal in the visible light region and the theoretical value of the pure metal is within 0.2%.
The metal film as described. 12. The metal film according to claim 11, wherein the change in reflectance is 0.5% or less when the incident angle of light is in the range of 10 to 50 °. 13. The metal film according to claim 9, wherein a difference between a reflectance of the pure metal at a light wavelength of 250 to 400 nm and a theoretical value of the pure metal is within 0.2%. 14. Ag, Cu, Au, Pt, Al, Ti,
The metal film according to claim 9, wherein the metal film is at least one of Cr, Ni, Fe, W, Zn, and Si. 15. A step of holding a substrate on which a metal thin film is to be formed on a surface in a chamber, a step of supplying a gas for generating plasma into the chamber, and a step of supplying a high frequency wave to a space in the chamber. Applying an electric field, heating and evaporating an evaporating material as a raw material of the thin film in the chamber, and supplying a gas for generating plasma to the chamber by forming a thin film on the base material. A gas supply amount control step of controlling the subsequent period to be less than at the beginning of the thin film formation, wherein the temperature of the base material is kept at 80 ° C. or less during the thin film formation. A metal film formed by the method. 16. The metal film according to claim 15, wherein the arithmetic average roughness of the surface is 2 nm or less, and the (111) peak intensity by X-ray diffraction is 20 times or more of the sum of other peak intensities. 17. A thin film forming method comprising a step of applying a DC voltage between said substrate and a boat holding an evaporating material with said boat side as an anode side.
Or a metal film according to 16. 18. The method according to claim 15, wherein said chamber is formed by a method for forming a thin film in an electrically floating state.
8. The metal film according to any one of 7. 19. A metal film having a surface having an arithmetic average roughness of 2 nm or less and a (111) peak intensity by X-ray diffraction of 20 times or more of a total of other peak intensities, and in a visible light region. An optical coating characterized in that the difference between the reflectance and the theoretical value of a pure metal is within 0.2%. 20. The optical coating according to claim 19, wherein the amount of change in reflectance is 0.5% or less when the incident angle of light is in the range of 10 to 50 °. 21. A metal film having a surface having an arithmetic average roughness of 2 nm or less and a (111) peak intensity by X-ray diffraction of 20 times or more of a total of other peak intensities, and having a light wavelength of 250 to 250 nm. An optical coating, wherein the difference between the reflectance at 400 nm and the theoretical value of pure metal is within 0.2%. 22. The optical coating according to claim 19, wherein said metal film is silver or aluminum.