JP2007291529A - Metal film-coated member and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dense metal film of a single crystal that has very low surface roughness, very good crystal orientation and excellent optical characteristics; to provide a metal film-coated member; and to provide an optical film. <P>SOLUTION: The metal film has an arithmetic mean roughness of the surface of not larger than 2 nm and a (111) peak intensity of X-ray diffraction of not less than 20 times the sum of all other peak intensity, and the metal film-coated member is made by forming the metal film on a substrate. The optical film is made of the metal film, and a difference in the reflectivity from the theoretical value of a pure metal being as small as 0.2% or less, in the visible light region. In this case, variations in the reflectivity are not more than 0.5%, in a range of incident angles of light from 10 to 50 ° or a difference in the reflectivity from the theoretical value of a pure metal being as small as 0.2% or less, in a range of wavelengths of light from 250 to 400 nm. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a novel metal film, a metal film-coated member, and an optical film using the same.

Conventionally, a metal film is applied to various substrates for the purpose of decoration, improvement of electrical characteristics, use in the optical field, and the like. Depending on the purpose of these metal films, the physical properties inherent to the metal itself such as the texture such as gloss and color, electrical properties, and optical properties are used. It is hoped that it is stable without being damaged for a long time.
In particular, in the case of a metal film used for optical applications such as a reflector such as silver and aluminum, characteristics such as reflectance, spectral characteristics, and durability are important issues. For example, in a reflection mirror or 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 there is unevenness in the spectrum, it directly affects the unevenness in color of the projected image, so that flat reflection characteristics are required in the wavelength region to be used. At this time, since the angle at which the light beam enters the reflecting surface is in the range of 10 ° to 50 °, 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 deposition is extremely poor in environmental resistance, and if left in the air as it is after deposition, an oxide film is formed on the surface in about 24 hours, resulting in white turbidity. In this case, it will be blackened and peeled off. Further, if the metal film does not have sufficient adhesion to the base material, moisture penetrates into the interface with the base material and corrosion occurs.

  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 by plasma from a glow discharge or a high-frequency antenna under reduced pressure, and a metal film is deposited on a substrate to which a negative bias voltage is applied. The metal film is also produced by a so-called resistance heating vacuum deposition method in which an evaporation source is heated and vaporized by resistance heating and is attached to the substrate surface in a vacuum.

  However, since the metal film obtained by these methods has a rough surface and poor crystal orientation, it is difficult to obtain high reflection characteristics as described above. In addition, as described above, there is a problem that white turbidity is generated due to oxidation of the surface of the metal film and adhesion to the base material is poor.

  Furthermore, 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.

  The main object of the present invention is to provide a monocrystalline metal film and a metal film-coated member having a very small surface roughness and a very good 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 base material having a low heat-resistant temperature and have excellent adhesion to the base material. Still another object of the present invention is to provide an optical coating having excellent optical properties.

As a result of earnestly researching the present inventors to provide a thin film forming method excellent in adhesion to the substrate,
a. Connect the boat holding the thin film material (evaporation material) in the chamber to the anode side of the DC voltage application power source,
b. Placing the chamber in a floating state that is not electrically grounded; and c. By controlling the gas supply amount such as Ar gas for generating plasma so that the subsequent period is smaller than the initial stage of thin film formation for forming a thin film,
(1) Since no high-frequency discharge occurs 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 in the plasma or positive The charged particles are efficiently guided to the surface of the substrate, and the electrons in the plasma are concentrated to the evaporation material on the boat,
(2) When the plasma stabilizes, the evaporation material evaporates so that the evaporation material is sucked up by the irradiation of the electron beam from the plasma to the evaporation material,
(3) Electron in plasma intensively collides with the evaporating material, giving the evaporating material energy for evaporating, and the evaporating material that has obtained high energy instead of thermal energy easily evaporates even at low temperatures. As a result, it has been found that the heating energy of the evaporating material by resistance heating or the like can be remarkably reduced, the temperature rise of the substrate 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 previously filed a patent application for the thin film forming apparatus and the thin film forming method (Japanese Patent Application No. 2001-16711).

  Surprisingly, however, the present inventors have found that the metal film obtained by using such an apparatus and method is dense and has almost no defects in the film, so that the surface roughness (arithmetic average roughness, etc.) is low. The present inventors have found a new fact that it is very small (2 nm or less) and has a single crystalline structure with extremely good crystal orientation (crystals are aligned in one direction). The reason why such a metal film can be obtained is not clear, but it is presumed to be caused by the fact that the evaporation material is in a high energy state (excited state) by electron irradiation even though it is at a 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 total of other peak intensities.

The metal film of the present invention has the following characteristics due to such a configuration.
(1) The difference between the reflectivity in the visible light region (about 400 to 700 nm) and the theoretical value of pure metal is extremely small within 0.2%.
(2) When the light incident angle is in the range of 10 to 50 °, the change in reflectance is as small as 0.5% or less.
(3) The difference between the reflectivity of pure metals at a light wavelength of 250 to 400 nm (ultraviolet to blue range) is as small as 0.2% or less.
(4) Excellent adhesion to the substrate.
(5) Durability is drastically improved without corrosion even when exposed to the atmosphere.
The features (3) to (5) are particularly remarkable in an Ag film.

  Examples of the metal film of the present invention include at least one of Ag, Cu, Au, Pt, Al, Ti, Cr, Ni, Fe, W, Zn, and Si.

The metal film-coated member of the present invention is characterized in that the metal film is formed on a base material. Furthermore, in the present invention, an antireflection film made of a dielectric multilayer film may be formed on the surface of the metal film. Moreover, not only the antireflection film but also a reflection increasing film, a protective film, or the like may be used. Examples of the dielectric multilayer film include MgF ₂ , TiO ₂ , Al ₂ O ₃ , ZrO ₂ , and SiO ₂ .

  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-formed thin film material is deposited on the surface of a substrate held at 100 ° C. or lower, preferably 80 ° C. or lower, more preferably 60 ° C. or lower. The metal film 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 total of other peak intensities.

Specifically, the metal film of the present invention includes a step of holding a substrate on which a thin film made of metal is formed on the surface in a chamber, a step of supplying a gas for generating plasma into the chamber, A step of applying a high frequency electric field to the space in the chamber, a step of heating and evaporating an evaporation material as a raw material of the thin film in the chamber, and a supply amount of gas for generating plasma to the chamber, And a gas supply amount control step for controlling so that the subsequent period is less than the initial period of thin film formation for forming a thin film on the substrate, and the temperature of the substrate is set to 80 during the thin film formation period. It is characterized by being formed by a thin film forming method that is maintained at a temperature of ℃ or less. This metal film has an arithmetic average roughness of the surface of 2 nm or less, and a (111) peak intensity by X-ray diffraction is 20 times or more of the total of other peak intensities.
In the present invention, it is preferable to include a step of applying a DC voltage between the base material and the boat holding the evaporation material with the boat side as the anode side. The chamber is preferably in an electrically floating state.

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

  Another optical coating of the present invention comprises a metal film having an arithmetic average roughness of the surface of 2 nm or less and a (111) peak intensity by X-ray diffraction of 20 times or more of the total of other peak intensities. The difference between the reflectivity at a wavelength of 250 to 400 nm and the theoretical value of pure metal is within 0.2%. For example, silver, aluminum, copper, and chrome are preferable as the metal film used for these optical coatings, but they are particularly flat and have high reflection characteristics in the visible light region, and are also compared in a region with a small wavelength such as a blue region. Silver having high reflective properties is preferable.

  The metal film of the present invention has an effect that the surface roughness is very small, the crystal orientation is very good, and the optical properties are excellent. Furthermore, 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 that it has excellent adhesion to the substrate.

  Hereinafter, the present invention will be described in detail. The metal film of the present invention has a surface arithmetic average roughness of 2 nm or less, and a (111) peak intensity by X-ray diffraction is 20 times or more of the total of other peak intensities. The surface roughness of the metal film can be measured by observation with an atomic force microscope (AFM). An atomic force microscope uses the fact that when a cantilever with a probe is brought close to the sample surface, the cantilever bends due to the atomic force, and the displacement is detected by laser reflected light. A microscope that can be imaged with. That the surface roughness measured by such an atomic force microscope is 2 nm or less means that the surface is substantially flat. As a result, light scattering on the film surface, which causes a significant decrease in reflectance, is suppressed.

  Moreover, the (111) peak intensity by X-ray diffraction is 20 times or more of the total of other peak intensity. This means that the crystal orientation is high, the crystal density is high and dense, and the properties of the metal film are homogeneous. As a result, absorption and scattering of light into the film, which is a major cause of a decrease in reflectance, are suppressed. That is, light absorption means that light energy is converted into heat in the film and lost, and occurs when there are defects such as impurities in the film. Therefore, from the above points, the metal film of the present invention is dense and flat, and thus it is considered that high reflectance is realized by suppressing light scattering and absorption.

  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 evaporation source 20 that houses and holds the evaporation material 9 in the boat 1 is disposed in the lower portion of the chamber 11. A base material holding part 2 for holding the base material 10 is provided in the upper part of the chamber 11 so as to face the evaporation source 20.

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

  The boat 1 is made of, for example, a material having a high electrical resistance, and generates heat for evaporating the evaporating material 9 upon receiving power supply from a heating power source 3 including, for example, an AC power source. The boat 1 is further connected to the anode side of the DC voltage application power source 6.

  The space in the chamber 11 is evacuated by the vacuum pump 14 through the exhaust duct 12 and the exhaust valve 13 and is in a predetermined vacuum state during the thin film formation period. In order to supply an inert gas (for example, argon gas) into the chamber 11, an inert gas supply source 21 is connected to the chamber 11 via a flow rate controller (MFC) 24 and a gas supply pipe 25. Yes. Supply / stop from the inert gas supply source 21 is performed by opening and closing the valve 21a. The apparatus shown in FIG. 1 is provided with a reactive gas supply source 23 for supplying a reactive gas such as oxygen gas, but this is not used in the present invention.

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

  In order to measure the thin film formation speed on the surface of the substrate 10, a film thickness monitor 17 is provided in association with the substrate holder 2. 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 source 3 based on the output of the film thickness monitor 17. In this way, the energization amount to the boat 1 is controlled and the evaporation amount of the evaporating material 9 is adjusted so that the formation speed of the thin film 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 / second, preferably 15 to 18 Å / second.

The high-frequency power supply source 5 may be a high-frequency power source having a frequency of 10 to 50 MHz, for example, but may be set to a general 13.56 MHz, and the output 50 per unit area (cm ² ) of the substrate holding part 2 as a discharge electrode. A high frequency power of ˜800 mW, preferably 85 to 170 mW, is applied to the substrate holder 2. When a high-frequency electric field corresponding to this is formed in the chamber 11, plasma composed of the gas supplied from the gas supply pipe 25 and the evaporated material evaporated from the evaporation material 9 is generated in the chamber 11. Among the ionized particles in the plasma, positively charged particles 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 source 6. The applied voltage from the DC voltage applying power source 6 is 100 to 400V, preferably 180 to 230V.

  On the other hand, the dissociated electrons in the plasma are attracted to the boat 1 connected to the anode side of the DC voltage application power source 6. At this time, since the evaporation material 9 continuously evaporates from the evaporation source 20, a light emitter having a shape in which a plasma foot falls to the evaporation source 20 due to the collision between the evaporated particles and the electrons is the evaporation source 20. Can be seen in the vicinity of The electrons collected near the evaporation source 20 are sucked into the boat 1 that is grounded and connected to the anode side, and collide with the evaporation material 9 on the boat 1. As a result, evaporation of the evaporation material 9 is promoted by heating by the boat 1 and collision of electrons. That is, an effect of promoting evaporation at a low temperature (deposition assist effect) by concentrated electron collision with the evaporation material 9 can be obtained.

  As shown in FIG. 1, the chamber 11 is not connected to any of the DC voltage application power source 6 and the high frequency power supply source 5 and is not grounded. That is, the chamber 11 is in an electrically floating state. For this reason, high frequency discharge does not occur between the base material holder 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. Accordingly, positively-charged particles or positively-charged particles in the plasma are efficiently guided to the surface of the substrate 10, and electrons that are negatively charged particles in the plasma are transferred to the evaporation material 9 on the boat 1. It will be guided intensively. Thereby, while being able to implement | achieve favorable thin film formation, the evaporation promotion of the evaporation material 9 by an electron beam can be performed efficiently. Furthermore, 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 evaporation material 9 evaporates so as to be sucked up by the plasma by irradiation of the electron beam from the plasma onto the evaporation material 9. Therefore, the control device 30 reduces the output of the heating power source 3 based on the output of the film thickness monitor 17 in order to keep the deposition speed of the evaporation material 9 that adheres to the substrate 10 constant. That is, the energization current or energization voltage to the boat 1 is lowered. Thereby, the evaporation rate is adjusted.

  Since the evaporation of the evaporation material 9 is promoted by the electron beam supplied from the plasma, the heating current value of the boat 1 can be kept low, so that the evaporation material 9 is continuously maintained at a relatively low heating temperature. It is possible to form a thin film by vapor deposition utilizing the action of plasma.

  The thin film formation in this embodiment is characterized by a method for supplying an 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 pipe 25 As a result, the gas supply amount is reduced, so that plasma of an inert gas supplied from the gas supply pipe 25 is formed in the chamber 11 in the initial stage of thin film formation in which evaporation from the evaporation material 9 is not active. When evaporation from the evaporating material 9 becomes active, the amount of gas supplied from the gas supply pipe 25 decreases, and plasma having a composition in which the evaporated particles from the evaporating material 9 become dominant is formed in the chamber 11. .

  In this manner, by introducing the inert gas into the chamber 11 at the initial stage of thin film formation, stable plasma can be rapidly formed in the chamber 11. As a result, thin film formation utilizing the action of plasma can be performed from the initial stage, so that a thin film with 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 an example of a process for forming a thin film while supplying an inert gas from the inert gas supply source 21 into the chamber 11 when forming a metal film on the surface of the substrate 10. . Specifically, FIG. 2 (a) shows the time change of the gas supply amount, FIG. 2 (b) shows the time change of the degree of vacuum in the chamber 11, and FIG. 2 (c) shows the heating current value of the boat 1. The time change of is shown.

In the period T1 before the start of the film formation process, the control device 30, the exhaust valve 13 open and is evacuated atmosphere in the chamber 11 by the vacuum pump 14, about the vacuum degree in the chamber 11 is for example 10 ^-3 Pa Retained. From this state, the control device 30 opens the valve 21a at time t10 and starts the supply of gas from the inert gas supply source 21. After the gas supply is started, the control device 30 monitors the output signal of the vacuum gauge 15 to control the flow rate so that the vacuum in the chamber 11 is maintained at 2 × 10 ⁻² Pa, for example. The device 24 is controlled.

  Thus, plasma is generated in the chamber 11 by the high-frequency electric field applied from the high-frequency power supply source 5 during the period T2 when the energization of the boat 1 is started and the evaporation material 9 is heated. The ionized inert gas atoms and molecules 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 source 6. When an undesirable temperature rise of the substrate 10 occurs during the period T2 due to the collision of the inert gas atoms and molecules with the substrate 10, a shutter 18 is provided below the substrate 10 to What is necessary is just to block the inert gas which goes to 10.

  In the period T2, the control device 30 controls the heating power source 3 and starts energizing the boat 1. Along with this, the heating current value to the boat 1 increases, and reaches 150 A, for example, at the end of the period T2. At time t11 when the plasma in the chamber 11 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 a thin film. Since the evaporated particles are led into the plasma by the evaporation of the evaporation material 9, if the gas is supplied into the chamber 11 from the gas supply pipe 25 at a constant flow rate, the degree of vacuum in the chamber 11 is lowered.

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

  On the other hand, since the evaporation from the evaporating material 9 is promoted by the supply of electrons from the plasma, the current supplied to the boat 1 from the heating power source 3 by the feedback control based on the output of the film thickness monitor 17 is denoted by reference symbol B. Will decrease as shown. For example, the current value decreases from 150 A to 80 A after a period of about 2 to 3 seconds. For this reason, the evaporation material 9 evaporates at a lower temperature than in normal vapor deposition or ion plating, and thus the substrate 10 may be excessively heated by the radiant heat from the evaporation source 20. Absent.

  As described above, according to this embodiment, good plasma can be generated in the chamber 11 from the initial stage of the thin film formation by starting the thin film formation with the inert gas introduced into the chamber 11. . Thereby, the evaporation material is efficiently guided to the base material 10 while receiving the action of plasma from the initial stage. As a result, a metal film with good adhesion can be efficiently formed on the surface of the substrate 10.

  In this metal film forming method, the base material 10 is kept at 100 ° C. or lower, preferably 80 ° C. or lower, more preferably 60 ° C. or lower, so that the base material such as glass, ceramics, semiconductor material, metal material or plastic, It is suitable for forming a metal film on the substrate 10 such as a resin film. For example, the heat resistance temperature of polycarbonate is 120 to 130 ° C., and the heat resistance temperature of polymethyl methacrylate is about 80 ° C. Therefore, a metal film can be formed on these base materials 10.

  FIG. 3 shows another example of a thin film forming apparatus used in the present invention. In the figure, the same components as those in FIG. This apparatus includes a feeding roller 31 in which a strip-shaped film base material 10A (resin film or the like) is wound in a chamber 11, and a take-up roller 32 for winding up the film base material 10A fed from the feeding roller 31. Are arranged, and a high-frequency shaft electrode 2A as a substrate holding part is arranged between them. In addition, auxiliary shafts 33 and 34 are disposed on both sides of the high-frequency shaft electrode 2A.

  The high-frequency shaft electrode 2A is made of a round bar-like conductive member, and is applied with high-frequency power from the high-frequency power supply power source 5 and a DC bias from the DC voltage application power source 6. An adhesion preventing plate 35 having an opening 35a for exposing the film base 10A to the lower surface side of the high frequency shaft electrode 2A is disposed below the feeding roller 31 and the take-up roller 32. Further, a coating material supplier 36 for supplying the evaporation material to the boat 1 is arranged in relation to the evaporation source 20.

  With such a configuration, the metal film can be continuously formed on the surface of the film base 10 </ b> A fed out from the feed roller 31 while the film base 10 </ b> A is wound up by the take-up roller 32. Others are the same as those shown in FIGS.

  Thus, according to this metal film forming method, the gas for forming plasma is supplied into the chamber 11, so that plasma can be quickly generated in the chamber 11 at the initial stage of thin film formation. This makes it possible to produce a metal film utilizing the action of plasma from the initial stage of thin film formation, and to obtain a metal film having excellent adhesion to the substrate 10. Further, the amount of gas supplied into the chamber 11 is large at the initial stage of thin film formation, and then decreased, so that the base material 10 is produced by the collision of the atoms and molecules of the inert gas supplied into the chamber 11 with the base material 10. Temperature rise can be suppressed.

  Furthermore, positively charged particles or positively-charged particles in the plasma are accelerated toward the base material 10 by the direct current electric field applied from the direct current applied voltage power source 6 and collide with the base material 10. Deposits on the surface of the material 10. As a result, a film is formed. On the other hand, electrons having a negative charge are accelerated to the boat 1 on the anode side, intensively collide with the evaporation material 9 on the boat 1, and give the evaporation material 9 energy for evaporation. Thus, the evaporating material 9 that has obtained high energy instead of thermal energy easily evaporates even at a low temperature and evaporates into the plasma formation region in the chamber 11. That is, electrons in the plasma formed in the chamber 11 are guided to the evaporating material 9, thereby obtaining a so-called deposition assist effect that promotes evaporation of the material, so that the evaporating material 9 is heated by resistance heating or the like. Energy can be significantly reduced. As a result, since the temperature rise of the base material 10 can be suppressed, it is possible to form a thin film at a lower temperature.

  The thickness of the metal film of the present invention is about 500 to 1500 mm, preferably 800 to 1100 mm. A 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. The amount of evaporation from the evaporating material 9 is adjusted by controlling the energy applied to the heating means and the output of the DC voltage application power source 6 within the above range. Moreover, the collision energy of the particles of the evaporating material 9 to the substrate 10 is adjusted by controlling the output of the DC voltage application power source 6 within the above range. Thereby, the vapor deposition material is not simply deposited on the surface of the base material 10, but gives sufficient energy to rearrange the atomic or molecular arrangement of the vapor deposition material layer formed on the surface of the base material 10 in a stable state. be able to. Furthermore, sufficient energy can be imparted to the particles of the vapor deposition material to penetrate into the substrate 10 and adapt.

  For this reason, in the present invention, a flat film with few defects in the film, a dense film with excellent adhesion, and a metal film close to a pure single-crystal metal layer can be obtained.

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

(1) When the substrate 10 is glass, for example, a reflector and a light tunnel for a liquid crystal projector in which an Ag film is formed as a mirror film, an infrared reflector in which an Au film is formed as a reflection film, and a protective film as a reflection film Optical measuring instruments such as a combined photometer, laser interferometer, etc., with an Al film formed on the surface.
(2) When the substrate 10 is ceramic, a ceramic wiring board on which at least one of Au, Cu, Al, Ag, Pt, Ti, Cr, Ni, W, and Fe is formed as a conductor layer, for mounting a semiconductor element Substrate, semiconductor element storage container, etc.
(3) Infrared antireflection member or the like in which ZnS, Si, ZnS is sequentially formed on the base material 10 made of Si, Ge or the like when the base material 10 is a semiconductor material.
(4) When the substrate 10 is plastic, a highly reflective deformed mirror or the like in which a deformed substrate 10 having predetermined irregularities formed on the surface by molding is coated with Al, Ag or the like as a reflecting film.
(5) In the case where the substrate 10 is a resin film, a thin film resistor formed with Ti, Al, etc., a solar cell formed with a Si film, a thin film capacitor, etc.
(6) A condensing mirror or the like of an infrared lamp in which an Au film or the like is formed on the Al base material 10 as a reflection film when the base material 10 is a metal material.
(7) In addition, a metal film covering member or the like 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 deterioration of the metal film.

  In particular, the metal film of the present invention has an excellent optical characteristic that the difference between the reflectance in the visible light region and the theoretical value of pure metal is within 0.2%. It is optimal for use as an optical coating such as an antireflection film.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated in detail, this invention is not limited only to a following example.

Example 1
Using the thin film forming apparatus shown in FIG. 1, a silver film was produced by the process shown in FIG. The production conditions are shown below.
Substrate 10: 3 mm thick glass plate evaporation material 9: Gas introduced into the silver chamber 11: Argon gas High frequency power supply power applied from the power supply 5 to the substrate holder 2: 85 mW / cm at a frequency of 13.56 MHz ² (applied electric power per unit area of the substrate holder 2)
DC application power source 6: The cathode side is connected to the base material holding part 2, and the anode side is connected to the boat 1. Applied voltage from the DC application power source 6 to the base material holding part 2: 230V
Chamber 11: Formation rate of electrically floating metal film that is not grounded: 18 Å / sec (a) Initial stage of metal film formation (period T2 in FIG. 2)
The degree of vacuum in the chamber 11 is 2 × 10 ⁻² Pa, and the current supplied from the constant heating power source 3 to the boat 1 is 280 A (the end of T2).
(B) Metal film formation stage (period T3 in FIG. 2)
Degree of vacuum in the chamber 11: 2 × 10 ^-2 current supplied from a constant heating power source 3 in Pa to the boat 1: 210A (T3 end)
Thus, a silver film having a thickness of 1500 mm could be produced 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 because the thermoseal that reacts at 40 ° C. reacted slightly.

Comparative Example 1
A silver film having a thickness of 1500 mm was formed on the surface of the base material 53 (a glass plate having a thickness of 3 mm) using a normal ion plating apparatus shown in FIG. This apparatus generates plasma in the vicinity of an antenna 51 connected to a high-frequency power supply 50 (applied power is 400 W at a frequency of 13.56 MHz). Argon gas is introduced into the chamber 52, and the degree of vacuum is set to 2 × 10 ⁻² Pa. The base 53 and the chamber 52 are grounded at the same potential, and a silver film is formed on the surface of the base 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
A silver film having a thickness of 1500 mm was formed on the surface of the substrate 63 (a glass plate having a thickness of 3 mm) using a normal resistance heating type vacuum vapor deposition apparatus shown in FIG. In this apparatus, the evaporation material 64 (silver) is heated and vaporized by the heating current 320A from the AC power supply 65 in the chamber 62 in which the degree of vacuum is set to 2 × 10 ⁻² Pa, and is deposited on the base 63. It is what I did.

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

1. Surface roughness of the silver film The surface state of the prepared silver film with a thickness of about 1500 mm is observed with an atomic force microscope (AFM, Nano Scope II manufactured by Digital Instruments), and the unevenness of the film surface is imaged in nanometer order. From this, the arithmetic average roughness (Ra) was examined. As a result, the silver film of Example 1 was 2 nm or less, while the silver films of Comparative Examples 1 and 2 were both about 3 to 5 nm.

2. (111) peak intensity by X-ray diffraction Using an X-ray diffractometer (RINT1400V type manufactured by Rigaku Corporation), X-ray output 50 kV-200 mA, measuring range 2 mm = 10 ° to 100 °, light emitting slit-scattering slit-light receiving The slit was measured at 1 ° -1 ° -0.3 mm. As a result, in the silver film of the example, the (111) peak intensity was 20 times or more the total of other peak intensities. On the other hand, the silver films of Comparative Examples 1 and 2 were 2 to 15 times.

3. Reflectivity
(1) Reflectance measurement in the visible light region The reflectance in the visible light region (about 400 to 700 nm) was measured with a photometer (Spectrophotometer U-4000 manufactured by Hitachi, Ltd.). As a result, in the silver film of the example, the difference in reflectance from the theoretical value in pure metal was within 0.2%. In contrast, the silver films of Comparative Examples 1 and 2 were both within 2%. In addition, the theoretical value was calculated | required from the refractive index of the pure silver as described in a basic physical property chart (Kyoritsu Publishing Co., Ltd., May 15, 1972, pp. 128-131 (silver)).
(2) Change in reflectivity The change in reflectivity was measured with the same photometer as in (1) above in the range of the incident angle of light of 10 to 50 °. As a result, the change amount of the reflectance was within 0.5% in the silver film of the example. 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 reflectivity at a light wavelength of 250 to 400 nm was measured with the same photometer as in (1) above. As a result, in the silver film of the example, the difference from the theoretical value in pure metal was within 0.5%. On the other hand, the silver films of Comparative Examples 1 and 2 were both 10 to 15%. The theoretical value is the reflectance of pure silver described in the basic physical property chart.

4). Environmental resistance According to MIL-M-13508, after maintaining at a temperature of 50 ° C. and a humidity of 95% for 24 hours, the surface of the silver film was observed. As a result, no white turbidity was generated on the surface of the silver film of the example, but white turbidity was generated in the silver films of Comparative Examples 1 and 2.
5). Adhesion The tape test described in MIL-M-13508 was conducted to examine the adhesion. As a result, the silver film of the example did not peel off, but the silver films of Comparative Examples 1 and 2 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, the method (B) of Comparative Example 2, and the method (C) of Example 1 ) Was used to form an Al film having a thickness of about 1100 mm. The production conditions for each sample are as follows.
A: Conventional ion-plated product obtained in the same manner as in Comparative Example 1 except that aluminum was used instead of silver as the evaporation material and the high frequency output was changed from 400 W to 380 W.
B: Conventional resistance heating product obtained in the same manner as in Comparative Example 2 except that aluminum was used instead of silver as the evaporation material and the thin film formation rate was changed from 18 Å / sec to 15 Å / sec.
C: The same as in Example 1 except that aluminum was used instead of silver as the evaporation material, and the high frequency output and thin film formation speed were changed from 85 mW / cm ² and 18 Å / sec to 80 mW / cm ² and 15 Å / sec, respectively. The product of the present invention obtained.
(1) The surface roughness of each sample obtained was measured by the method described above. The result is shown in FIG. If the sample name is G-AL-A, for example, it indicates that an aluminum (AL) film is formed on the surface of the glass (G) substrate 10 by the method (A) of Comparative Example 1.
(2) The reflectance measurement results of each sample are shown in FIGS.
(3) X-ray diffraction measurement results of each Al film obtained using the method (C) of Example 1, the method (A) of Comparative Example 1, and the method (B) of Comparative Example 2 are shown in FIGS. Show.

Test example 2
(Preparation of copper film)
In the same manner as in Test Example 1, the method (C) of Example 1 and the method (A) of Comparative Example 1 were applied to the surface of each substrate 10 of glass (G), polycarbonate (PC), and polymethyl methacrylate (PM). Using the method (B) of Comparative Example 2, a Cu film having a thickness of about 1300 mm was formed. The production conditions for each sample are as follows.
A: Conventional ion plate obtained in the same manner as in Comparative Example 1 except that copper was used instead of silver as the evaporation material, and the high frequency output and thin film formation speed were changed from 400 W and 18 Å / sec to 420 W and 12 Å / sec, respectively. Ting goods.
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 evaporation material and the thin film formation rate was changed from 18 Å / sec to 12 Å / sec.
C: The same as in Example 1 except that copper was used instead of silver as the evaporation material, and the high frequency output and thin film formation speed were changed from 85 mW / cm ² and 18 Å / sec to 88 mW / cm ² and 12 Å / sec, respectively. The product of the present invention obtained.
(1) The surface roughness of each sample obtained was measured by the method described above. The result is shown in FIG. If the sample name is G-Cu-A, for example, it indicates that a copper (Cu) film is formed on the surface of the glass (G) substrate 10 by the method (A) of Comparative Example 1.
(2) The reflectance measurement results of each sample are shown in FIGS.
(3) FIG. 17 shows the reflectance characteristics in the range of light wavelengths from 250 to 700 nm for the same graph as FIG. The literature values shown in the figure indicate the values described on pages 422 to 429 (copper) of the basic physical property chart.

It is a conceptual diagram which shows an example of the thin film formation apparatus for manufacturing the metal film of this invention. It is explanatory drawing which shows the process of thin film formation. It is a conceptual diagram which shows the other example of a thin film forming apparatus. It is the schematic which shows the normal ion plating apparatus used in order to form a metal film in the comparative example 1. It is the schematic which shows the vacuum evaporation apparatus of the resistance heating system used in order to form a metal film in the comparative example 2. 4 is a graph showing the relationship between the deposition method and surface roughness for each Al film obtained in Test Example 1. 5 is a graph showing the reflectance of each Al film / glass substrate obtained in Test Example 1. FIG. 3 is a graph showing the reflectance of each Al film / polycarbonate substrate obtained in Test Example 1. FIG. 4 is a graph showing the reflectance of each Al film / polymethyl methacrylate substrate obtained in Test Example 1. FIG. In Experiment 1, it is a graph which shows the X-ray-diffraction measurement result of Al film | membrane (this invention product C) obtained using the method of Example 1. FIG. In Test example 1, it is a graph which shows the X-ray-diffraction measurement result of Al film | membrane (conventional ion plating goods A) obtained using the method of the comparative example 1. FIG. In Test Example 1, it is a graph which shows the X-ray-diffraction measurement result of Al film | membrane (conventional resistance heating goods B) obtained using the method of the comparative example 2. FIG. It is a graph which shows the relationship between the vapor deposition method about each Cu film | membrane obtained in Test Example 2, and surface roughness. 6 is a graph showing the reflectance of each Cu film / glass substrate obtained in Test Example 2. FIG. 6 is a graph showing the reflectance of each Cu film / polycarbonate substrate obtained in Test Example 2. FIG. 6 is a graph showing the reflectance of each Cu film / polymethyl methacrylate substrate obtained in Test Example 2. FIG. In Test Example 2, the same graph as FIG. 14 is a graph showing the reflectance characteristics in the range of light wavelengths ranging from 250 to 700 nm.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Boat 3 Heating power source 4 Matching apparatus 5 High frequency electric power supply power source 6 DC voltage application power source 9 Evaporating material 10 Base material 11 Chamber 20 Evaporating source

Claims (22)

A metal film having an arithmetic average roughness of a surface of 2 nm or less, and a (111) peak intensity by X-ray diffraction being 20 times or more of a total of other peak intensities. The metal film according to claim 1, wherein the difference in reflectance in the visible light region from the theoretical value of pure metal is within 0.2%. 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 10 to 50 °. The metal film according to claim 1, wherein the difference between the reflectance of pure metal at a light wavelength of 250 to 400 nm and a theoretical value is within 0.2%. The metal film according to claim 1, which is at least one of Ag, Cu, Au, Pt, Al, Ti, Cr, Ni, Fe, W, Zn, and Si. A metal film-covered member, wherein the metal film according to claim 1 is formed on a base material. 7. The metal film covering member according to claim 6, wherein an antireflection film made of a dielectric multilayer film is formed on the surface of the metal film. The metal film-coated member according to claim 6 or 7, wherein the substrate is made of glass, ceramics, semiconductor material, metal material, or plastic. A metal film formed by a thin film forming method in which a plasma-formed thin film material is deposited on the surface of a substrate held at 100 ° C. or less, the arithmetic average roughness of the surface being 2 nm or less, and X-ray diffraction (111) The peak intensity of the metal film is 20 times or more the total of the other peak intensities. The metal film of Claim 9 formed in the state whose temperature of the said base material is 80 degrees C or less. The metal film according to claim 9 or 10, wherein a difference between a reflectance in a visible light region and a theoretical value of pure metal is within 0.2%. The metal film according to claim 11, wherein the amount of change in reflectance is 0.5% or less when the incident angle of light is 10 to 50 °. The metal film according to claim 9 or 10, wherein a difference between the reflectance of pure metal at a light wavelength of 250 to 400 nm and a theoretical value is within 0.2%. The metal film according to claim 9, which is at least one of Ag, Cu, Au, Pt, Al, Ti, Cr, Ni, Fe, W, Zn, and Si. A step of holding a substrate on which a thin film made of a metal is to be formed on the surface, a step of supplying a gas for generating plasma into the chamber, and a step of applying a high-frequency electric field to the space in the chamber And a step of heating and evaporating an evaporation material that is a raw material of the thin film in the chamber, and a supply amount of a gas for generating plasma to the chamber. And a gas supply amount control step for controlling so that the subsequent period is smaller, and formed by a thin film forming method for maintaining the temperature of the base material at 80 ° C. or lower during the thin film formation period. A metal film characterized by that. 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 total of other peak intensities. The metal film according to claim 15 or 16, wherein the metal film is formed by a thin film forming method including a step of applying a direct current voltage between the base material and the boat holding the evaporation material with the boat side as an anode side. The metal film according to claim 15, wherein the chamber is formed by a thin film forming method in which the chamber is electrically floating. Pure metal having a reflectance of light in the visible light region, comprising a metal film having a surface arithmetic average roughness of 2 nm or less and a (111) peak intensity by X-ray diffraction of 20 times or more of the total of other peak intensities An optical film characterized in that the difference from the theoretical value in is within 0.2%. 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 °. Reflectance at a light wavelength of 250 to 400 nm, consisting of a metal film 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 total of other peak intensities An optical coating characterized in that the difference from the theoretical value of pure metal is within 0.2%. The optical film according to any one of claims 19 to 21, wherein the metal film is silver or aluminum.

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