TWI431133B - Vacuum film forming apparatus and vacuum film forming method - Google Patents

Description

Vacuum film forming device and vacuum film forming method

The present invention relates to a vacuum film forming apparatus and a vacuum film forming method, and more particularly to a technique for improving the characteristics of a reflective film deposited on a substrate by a vacuum film forming apparatus.

With the increase in the performance of optical elements such as recording media such as magneto-optical disks and reflectors for lamps, the requirements for reflective films as such basic functional films have become strict. For this reason, development of products having high reflectance and excellent environmental resistance and having economic benefits is desirable.

However, silver (Ag), which is a material of a reflective film, is a material having the highest reflectance in a visible light wavelength region, but relatively deteriorates in environmental resistance due to yellowing and white turbidity in a high-temperature and high-humidity environment. Produces the disadvantage of reduced reflectivity. As a countermeasure against this disadvantage, it is considered that when bismuth (Bi), copper (Cu), niobium (Nd) or the like is added to Ag, environmental resistance can be improved. However, the addition of such an additive to Ag is deposited on the reflective film of the substrate. The initial reflectance is far from the initial reflectance of the reflective film composed of pure silver (hereinafter, abbreviated as "pure Ag").

Therefore, there has been an attempt to improve the initial reflectance and environmental resistance of the sputter film (reflective film) on the substrate by appropriately adjusting the additive amount (concentration) of the alloy material of Ag and the additive by using a sputtering apparatus on the substrate. Both of them (for example, refer to Patent Document 1 and Non-Patent Document 1 which are conventional examples).

Patent Document 1: JP-A-2005-15893 (Table 3)

Non-Patent Document 1: Kobe Steel Technology Bulletin, Vol. 55, No. 1 (Apr. 2005) P17~P20

In Non-Patent Document 1, it is described that the initial reflectance of a reflective film composed of an alloy of Ag and Bi (hereinafter, abbreviated as "Ag/Bi alloy") can be adjusted by adding an additive such as Bi to Ag. However, in reality, any data described in the same technical report cannot be obtained in the entire range of the visible light band, and the initial reflectance reaches the Ag/Bi alloy reflective film which is about the same level as the reflective film composed of pure Ag. (For example, refer to FIG. 3 of Non-Patent Document 1).

Patent Document 1 discloses data on the initial reflectance of an Ag/Bi alloy reflective film and the reflectance of a reflective film made of pure Ag by reducing the amount of addition of Bi added to Ag. For example, in Table 3 of the same publication, it is revealed that by adjusting the addition amount of Bi to 0.01 atom%, the reflectance (about 90.8% at a wavelength of 405 nm) of a reflective film composed of pure Ag is approximately the same. The reflectance of the Ag/Bi alloy reflective film (90.1% at a wavelength of 405 nm).

The reflectance described in Patent Document 1 refers to any of the relative reflectance and the absolute reflectance, and the incident light angle at the time of measuring the reflectance is set to several degrees, and it is not directly known from the description of Patent Document 1. However, as long as the reflectance (90.1% at a wavelength of 405 nm) is regarded as 45. In the case of the absolute reflectance, the absolute reflectance of the reflective film made of pure Ag at the initial wavelength of 400 nm is about 95%, and the result of the experiment by the inventors of the present invention is about 95%. /Bi alloy reflective film, not to a sufficient degree of reflectivity. Further, when the amount of addition of Bi is as low as 0.01 at%, there is a doubt that an appropriate environmental resistance of the reflective film can be obtained.

The present invention has been made in view of such circumstances, and an object thereof is to provide a vacuum film forming apparatus and a vacuum film forming method, which can achieve a reflectance at the initial stage of substrate deposition which is about the same as that of a reflective film composed of pure Ag, and is in silver. A reflective film made of a material containing bismuth and excellent in environmental resistance.

The reflectance improvement technique of the Ag/Bi alloy reflective film described in the conventional example is considered to be a case where the influence of the reflectance of the Ag/Bi alloy reflective film is neglected and it is an important process parameter in the vacuum deposition process. For example, when an ion plating apparatus is used as the vacuum film forming apparatus, the neglected parameter may be a substrate having an kinetic energy added when the ionized material (which is a raw material of the reflective film on the substrate) is deposited on the substrate. Use it for bias.

Therefore, the present invention is designed based on the knowledge that the vacuum film forming apparatus of the present invention includes: a vacuum chamber capable of internal pressure reduction; and a substrate holder for holding the substrate in the vacuum chamber; a biasing power supply with a predetermined bias voltage; a material for arranging the material for the reflective film with silver added in the vacuum chamber; and releasing the foregoing material from the material to the substrate, and releasing the material a material releasing mechanism that ionizes the material; and a reflective film composed of the material is deposited on the substrate in such a manner that the kinetic energy of the ionized material is increased by the bias voltage, and the reflectance of the reflective film It is adjusted according to the aforementioned bias voltage and the amount of the aforementioned enthalpy.

Thus, by appropriately adjusting the bias voltage, and by appropriately adjusting the amount of germanium added to the material for the reflective film added to the silver, the substrate can be deposited to the same extent as the reflective film composed of pure silver. A reflective film having an initial reflectance and excellent environmental resistance by the material.

In addition, the material device is a hearth that accommodates the material, and the material release mechanism may further include a plasma gun that releases an electron beam that heats and evaporates the material in the hearth. And the plasma-evaporated material is ionized by the plasma generated by the electron beam.

Thereby, an ion plating apparatus using a plasma gun can be obtained, and a reflective film excellent in environmental resistance can be formed on the substrate (the initial reflectance is about the same as that of the reflective film composed of pure silver, and is in silver) Adding materials with defects)

Further, when the vacuum chamber is grounded, the absolute value of the bias voltage may be adjusted to 50 V or more and 70 V or less.

Thereby, it is possible to obtain a reflection film having a reflectance change amount which is less than or equal to a predetermined level in the entire visible light band, high temperature, and high humidity environment.

Further, the amount of the ruthenium added may be adjusted to about 0.5% by weight.

Thereby, in the case where the bias voltage is set to 0 V, a reflection film having a reflectance change amount of 1.0% or less in the entire visible light band, high temperature, and high humidity environment can be obtained.

In the vacuum film forming method of the present invention, a substrate is disposed in a substrate in a vacuum chamber, and a material in the vacuum chamber is disposed on a material for a reflective film in which silver is added, and the inside of the vacuum chamber 4 is depressurized. Applying a bias voltage to the substrate, when the material is released to the substrate, by ionizing the material, the kinetic energy of the material is increased by the bias voltage, and the substrate is deposited with the reflection of the material. The film, and the reflectance of the reflective film is adjusted according to the bias voltage and the concentration of the ruthenium.

In this way, the bias voltage is appropriately adjusted, and the amount of the material for the silver-based reflective film is appropriately adjusted, whereby the reflectance can be made up of pure silver at the initial stage of substrate deposition. A reflective film having a reflection film of approximately the same degree and having excellent environmental resistance by the material.

Further, when the vacuum chamber is grounded, the absolute value of the bias voltage may be adjusted to 50 V or more and 70 V or less.

As a result, it is possible to obtain a reflective film having a reflectance change amount which is less than or equal to a predetermined level in the entire visible light band and in a high-temperature and high-humidity environment.

Further, the amount of the ruthenium added may be adjusted to about 0.5% by weight. Thereby, in the case where the bias voltage is set to 0 V, a reflection film having a reflectance change amount of 1.0% or less in the entire visible light band, high temperature, and high humidity environment can be obtained.

The above and other objects, features and advantages of the present invention will become apparent from

According to the present invention, it is possible to obtain a vacuum film forming apparatus and a vacuum film forming method which are capable of achieving a reflectance at an initial stage of substrate deposition which is approximately equal to that of a reflective film composed of pure Ag, and which is composed of a material which is added with silver. A reflective film that is excellent in environmental resistance.

Hereinafter, the best mode for carrying out the invention will be described with reference to the drawings.

Fig. 1 is a view showing an example of the internal structure of a vacuum film forming apparatus according to an embodiment of the present invention.

1 is a view showing an optical reflection film (metal) for opening a door (not shown) for inserting and removing the ruthenium substrate 11 and mounting the substrate 11 on the substrate member 12 for vapor deposition on the ruthenium substrate 11. The material 13 for the film is placed in the state of the hearth 15 of the vacuum film forming apparatus 100 in the state of the hearth 15 (material material).

As the material 13 for the vacuum film forming process herein, as described above, the viewpoint of ensuring high initial reflectance in the visible light band and ensuring the basic performance of environmental resistance, and the easy availability and economy of the material 13 are obtained. From the viewpoint of silver (Ag), an Ag/Bi material 13 (for example, an alloyed material of Ag and Bi) in which bismuth (Bi) is added in an appropriate amount is selected.

The vacuum film forming apparatus 100 (here, an ion plating apparatus) has a vacuum tank 20 in a grounded state as shown in FIG.

The inside 20e of the vacuum chamber 20 is depressurized by a vacuum exhausting device (not shown) that communicates with the exhaust hole 20a provided in the lower right side wall of the vacuum chamber 20. Further, the degree of vacuum of the inside of the vacuum chamber 20e is about 1 × 10 ^-3 Pa, and the degree of vacuum of the inside of the vacuum chamber 20e in the vacuum film forming process is about 2 × 10 ^-2 Pa (the pressure rises due to introduction of Ar gas).

Above the inside 20e of the vacuum chamber, a conductive substrate member 12 is disposed, which holds the ruthenium substrate 11 fixed from the back surface thereof. The substrate device 12 on which the substrate 11 is mounted is connected to a negative voltage side terminal of a bias DC power supply V1 that can set a direct current (DC) voltage in a range of at least zero volts to hundreds of volts. Further, the positive voltage terminal side of the bias DC power supply V1 is grounded. As a result, as will be described later, the vapor deposition particles which are evaporated and positively charged (ionized) by the hearth 15 are accelerated toward the substrate 11 by a negative DC voltage (corresponding to a substrate bias Bias which will be described later). Further, in the present embodiment, the temperature of the crucible substrate 11 is not controlled.

Below the inside of the vacuum chamber 10 inside 20e, a hearth 15 for accommodating the Ag/Bi material 13 and a material releasing mechanism are disposed. The material releasing mechanism is composed of various machines which can release the particles of the Ag/Bi material 13 for vapor deposition of the crucible substrate 11 to the crucible substrate 11 located above it, and when the particles are released, the particle ions are released. Chemical. For example, the material releasing mechanism is provided with a plasma gun 17 (the electron beam passing hole 20b disposed on the left side wall of the vacuum chamber 20, and the electron beam E of a large current is released into the vacuum chamber 20), and the gun The DC power source V2 (supplied power is supplied to the plasma gun 17) and the permanent magnet 18 (disposed on the back surface of the hearth 15 to introduce the electron beam E into the furnace by bending the direction of the electron beam E by about 90°) Inside bed 15).

The plasma gun 17 is a decompressible discharge space (not shown) that guides a discharge gas (Ar gas). In order to form and maintain a high-density Ar gas discharge plasma composed of electrons and Ar cations, a cathode (not shown) and an intermediate electrode (not shown) are disposed at appropriate places in the discharge space. Further, an electromagnetic air-core coil (not shown) for extracting electrons of a large current into the vacuum chamber 20 is disposed at an appropriate place outside the discharge space.

The terminal of the gun DC power supply V2 (negative voltage side) is connected to the cathode of the plasma gun 17, and the other terminal (positive voltage side) of the gun DC power supply V2 is connected to the anode through a suitable conductive covering member. Hearth 15 Thereby, the plasma gun 17 is designed to discharge with the voltage of the gun DC power source V2, whereby the electron beam can be induced from the cathode to the hearth 15. Thus, by the energy of the electron beam E, the Ag/Bi material 13 in the hearth 15 is heated and evaporated. On the way to the ruthenium substrate 11, the evaporated Ag/Bi material 13 particles are deprived of electrons in the plasma region generated by the electron beam E in the vicinity of the hearth 15, and the ionization becomes positively charged. Thereby, the particles are accelerated toward the substrate 12 to which the negative DC voltage is applied by the bias DC power supply V1 so that the kinetic energy is increased. As a result, a dense vapor deposited film can be deposited on the ruthenium substrate 11. Further, the negative DC voltage applied to the substrate member 12 has an important function of determining the reflectance characteristics of the reflective film in the case where the Ag/Bi material 13 is used as the optical reflection film material as will be described in detail later.

Thus, the Ag/Bi material 13 added to the hearth 15 can be heated and evaporated by the electron beam E, and at the same time, the plasma obtained by the electron beam E can be used to ionize the evaporated particles efficiently.

<About the evaluation of the initial reflectance of the reflective film>

Next, the initial reflectance characteristics of the reflective film on which the Ag/Bi material 13 is vapor-deposited will be described as a result of verifying the relationship between the substrate bias Bias (which is a negative DC voltage applied to the substrate member 12).

2 and 3 are graphs showing the initial reflectance of a reflective film made of an Ag/Bi material and the reflectance of a reflective film made of pure Ag in the visible light band.

In FIG. 2, when the substrate bias Bias is set to zero volt (0 V), the "wavelength" of the reflected light is taken as the horizontal axis, and the "45° absolute reflectance" is taken as the vertical axis, which shows various reflective films. The relationship between the two. As the reflection film of Fig. 2, a reflection film (hereinafter, abbreviated as "pure Ag reflection film") by using pure Ag as a vapor deposition device 100 (refer to Fig. 1) is selected; the use concentration is about 1.82 by weight. Percentage (hereinafter, "weight percentage" is abbreviated as "wt%") Bi, a commercially available Ag and Bi alloyed material, and a reflective film deposited by the vacuum film forming apparatus 100 (hereinafter, abbreviated as "Ag/ Bi (1.82 wt%) reflective film"); and using a mixed material (the Ag particles added to the hearth 15 (refer to FIG. 1) and the Bi particles are physically mixed, thereby adjusting the weight ratio of Bi to about 1 wt%. Concentration) A reflection film deposited by the vacuum film forming apparatus 100 (hereinafter, abbreviated as "Ag/Bi (1 wt%) reflection film").

In FIG. 3, regarding the Ag/Bi (1.82 wt%) reflective film, the "wavelength" of the reflected light is the horizontal axis, the "45 ° absolute reflectance" is taken as the vertical axis, and the substrate bias Bias is taken as the parameter. The relationship is shown in comparison with a pure Ag reflective film. As the substrate bias Bias (absolute value) of FIG. 3, voltages of |Bias|=0V, 30V, 70V, and 100V were selected.

First, the principle of measurement of "45° absolute reflectance" on the vertical axis of Figs. 2 and 3 will be described with reference to Fig. 7 .

Fig. 7 is a view showing the measurement principle of a spectrophotometer (manufactured by Hitachi High-Technologies Co., Ltd.; model "Hitachi spectrophotometer U-4100") for evaluating the absolute reflectance of the reflective film at 45°. In addition, here, a 45° specular attachment and a polarizing element are provided as optional components of the measuring device, and the detailed description of the spectrophotometer is omitted here.

The reflectance of the reflective film also means that the ratio of the intensity of the reflected light of the sample to the intensity of the reflected light of the reference mirror is the relative reflectance, and the absolute reflectance of the reflective film can be measured using the spectrophotometer. Thereby, the reflectance measurement of the reflective film can be performed with high precision.

In Fig. 7, first, in a state where no sample is provided, light emitted from the light source L is split by the optical filter F to a predetermined wavelength (for example, 400 nm), and the optical path of the mirror M1 and the mirror M2 is referred to (refer to After the solid line in Fig. 7, the intensity of this light is measured. In this way, the baseline measurement of the mirrors M1, M2 can be performed.

Next, in a state where the sample is set, the position of the mirror M1 is moved to the position of the mirror M1', and the mirror M2 is rotated to the position of the mirror M2'. Then, the light of the split light is passed through the optical path of the mirror M1' and the mirror M2' (see the broken line in Fig. 7), and the intensity of the light is measured.

The optical paths of the two are equal to each other, and the absolute reflectance of the sample can be measured by making the incident light angles and the optical path lengths of the mirrors M1, M1', M2, and M2' equal. In addition, the absolute reflectance measurement is performed by appropriately changing the incident light angle θ of the light to be split, and in the present embodiment, 45° absolute reflectance using 45° as the incident light angle θ is evaluated.

According to Fig. 2, it was confirmed that the initial reflectance of the Ag/Bi (1.82 wt%) reflective film (refer to the two-point chain line of Fig. 2) and the initial reflection of the Ag/Bi (1 wt%) reflective film in the entire range of the visible light band. Both of the rates (see the broken line in Fig. 2) are inferior to the initial reflectance of the pure Ag reflective film (see the solid line in Fig. 2). For example, the initial reflectance of a pure Ag reflective film having a wavelength of 400 nm is about 94.8%. In contrast, the initial reflectance of an Ag/Bi (1.82 wt%) reflective film having a wavelength of 400 nm is about 90.7%, and Ag/Bi having a wavelength of 400 nm. The initial reflectance of the (1 wt%) reflective film was about 91.6%.

According to FIG. 3, it is understood that the substrate bias Bias (absolute value) is 0 V (see the solid line in FIG. 3), 30 V (see the long dotted line in FIG. 3), and 70 V in the entire range of the visible light band (see FIG. 3). The initial reflectance of the Ag/Bi (1.82wt%) reflective film is asymptotic with the increase of the substrate bias Bias (absolute value) when the chain line) and 100V (see the two-point chain line in Fig. 3) are changed. The initial reflectance of the pure Ag reflective film (short dashed line in Figure 3). For example, if the initial reflectance of the pure Ag reflective film is about 94.8% with respect to a wavelength of 400 nm, the initial reflectance of the Ag/Bi (1.82 wt%) reflective film having a substrate bias Bias of 0 V is about 90.7%, the initial reflectance is about 94.3% with the same voltage Bias as 30V, the initial reflectance is about 94.3% when the same voltage Bias is 70V, and the initial reflectance is about 94.8 when the same voltage Bias is set to 100V. %.

By adding such a substrate bias Bias, it was found that the initial reflectance of the Ag/Bi (1.82 wt%) reflective film can be improved. Further, from the viewpoint of improving the initial reflectance of the reflective film, it is considered that the range (absolute value) suitable for the substrate bias Bias is 30 V or more. Thereby, it is possible to obtain a whole range of visible light (for example, 400 nm to 850 nm), and the initial reflectance (45° absolute reflectance) of the reflective film is about 94% or more equal to the reflectance of the pure Ag reflective film. Bi (1.82 wt%) reflective film.

Further, from the viewpoint of confirming the effect of improving the initial reflectance of the reflective film obtained by biasing the substrate bias Bias, the relationship between the substrate bias Bias and the film structure of the surface of the reflective film and the thickness direction was examined. The results of this test are described later.

<About environmental resistance evaluation of reflective film>

Next, the results of inspection on the relationship between the substrate bias Bias and the Bi concentration of the reflective film due to the influence of the high temperature and the high humidity environment on the reflectance of the reflective film will be described.

4 is a view showing a visible light band (for example, blue: a wavelength band near 400 n to a red band: a wavelength band around 800 nm), and an Ag/Bi (1.82 wt%) reflective film is caused by a high temperature and high humidity environment. A bar graph of the relationship between the amount of change in reflectance (vertical axis) and the substrate bias (horizontal axis) applied to the substrate. As the substrate bias Bias (absolute value) on the horizontal axis of Fig. 4, a voltage of |Bias| = 0V, |Bias| = 10V, 30V, 50V, 70V was selected.

5 is a graph showing the amount of change in reflectance (vertical axis) caused by a high-temperature and high-humidity environment of a reflective film made of Ag/Bi material when the substrate bias voltage is set to 0 V in the visible light band, and Bar graph of the correlation between Bi concentration (added amount; horizontal axis). Further, the weight ratio of Bi is adjusted by physically mixing the Ag particles added to the hearth 15 (see FIG. 1) with the Bi particles. Here, a pure Ag reflective film containing no Bi completely, a reflective film having a Bi concentration adjusted to 0.1% by weight, a reflective film having a Bi concentration adjusted to 0.5% by weight, and a reflective film having a Bi concentration adjusted to 1.0% by weight are selected. And the Bi concentration is a reflection film adjusted to 2.0 wt%.

Further, the reflection film to be measured was measured for 45° absolute reflectance of the reflective film after exposure to an atmosphere of a high temperature of 85° C. and a relative humidity of 90% and a high humidity atmosphere for 24 hours. For this reason, the amount of change in reflectance indicated by the vertical axis of FIGS. 4 and 5 means that the initial reflectance of the reflective film is subtracted from the reflectance of the reflective film after exposure to the above-mentioned high temperature and high humidity environment. The value (percentage) of the initial reflectance of the reflective film. Therefore, it means that the smaller the amount of change in reflectance (the closer to zero), the lower the degree of deterioration of the reflectance of the reflective film exposed to high temperature and high humidity, and the more excellent the environmental resistance of the reflective film.

According to Fig. 4, it is understood that the amount of change in the reflectance of the Ag/Bi (1.82 wt%) reflective film caused by the high temperature and high humidity environment varies depending on the substrate bias Bias (absolute value). For example, the amount of change in reflectance of a reflective film having a wavelength of 400 nm is about 2.9% at |Bias|=0V, about 4.4% at |Bias|=10V, about 2.3% at |Bias|=30V, at |Bias |=50V is about 2.5%, and |Bias|=70V is about 0.3%. Further, the amount of change in reflectance of the reflecting film having a wavelength of 600 nm is about 2.7% at |Bias|=0V, about 2.0% at |Bias|=10V, and about 1.4% at |Bias|=30V at |Bias |=50V is about 0.4%, and about |Bias|=70V is about 0.6%. Further, the reflectance change amount of the reflection film having a wavelength of 800 nm is about 1.4% at |Bias|=0V, about 1.8% at |Bias|=10V, about 1.3% at |Bias|=30V, at |Bias |=50V is about 0.1%, and about |Bias|=70V is about 0.6%.

From the above results, it is considered that the range (absolute value) suitable for the substrate bias Bias is in the range of 50 V or more and 70 V or less from the viewpoint of reducing the amount of change in the reflectance of the reflective film caused by the high temperature and high humidity environment. Thereby, the amount of change in reflectance caused by high temperature and high humidity environment is obtained in the entire visible light band, and the amount of change in reflectance is 1.0% or less (in the case of |Bias|=70V), Ag/Bi (1.82% by weight).

According to Fig. 5, it is understood that the amount of change in the reflectance of the Ag/Bi (1.82 wt%) reflective film caused by the high temperature and high humidity environment varies depending on the Bi concentration. For example, the amount of change in the reflectance of the reflective film having a wavelength of 400 nm is about 2.2% of the Bi concentration of 0 wt%, about 1.0% of the Bi concentration of 0.1 wt%, about 0.1% of the Bi concentration of 0.5 wt%, and the Bi concentration of 1.0. The wt% is about 1.112%, and the Bi concentration of 2.0 wt% is about 3.1%. Further, the reflectance change amount of the reflective film having a wavelength of 600 nm is about 1.0% of Bi concentration of about 0% by weight, about 1.4% of Bi concentration of 0.1% by weight, about 0.05% of Bi concentration of 0.5% by weight, and about 1.0% of Bi concentration. The wt% is about 0.4%, and the Bi concentration of 2.0 wt% is about 1.6%. Further, the reflectance change amount of the reflective film having a wavelength of 800 nm is about 0.9% at a Bi concentration of 0% by weight, about 0.7% at a Bi concentration of 0.1% by weight, about 0.05% at a Bi concentration of 0.5% by weight, and 1.0% at a Bi concentration. The % is about 0.6%, and the Bi concentration of 2.0 w1% is about 1.2%.

From the above results, from the viewpoint of reducing the amount of change in the reflectance of the reflective film caused by the high temperature and high humidity environment, it is considered that the appropriate value of the Bi concentration is a value of 0.5 wt%. Therefore, in the case where the substrate bias Bias is set to 0 V, an Ag/Bi (0.5 wt%) reflection in which the reflectance change amount of 1.0% or less is caused by the high temperature and high humidity environment can be obtained in the entire visible light band. membrane.

As described above, by setting the substrate bias Bias to 50 V or more, 70 V or less, and setting the Bi concentration to 0.5 wt%, it is possible to form a viewpoint of reducing the reflectance of the reflective film caused by the high temperature and high humidity environment. The most suitable reflective film.

<Relationship between substrate bias Bias and Bi concentration and surface property of reflective film>

Next, the surface of the reflective film is affected by the reflectance, and the relationship between the Bis concentration of the test substrate and the Bi concentration in the reflective film and the surface property of the reflective film will be described.

Fig. 6 is a view showing the results of observation of the surface of a reflective film obtained by a scanning electron microscope (FE-SEM). FIG. 6 shows a pure Ag reflective film, an Ag/Bi (1 wt%) reflective film, and Ag/Bi (1.82 wt%) in the case where the substrate bias Bias (absolute value) is set to 0 V, 30 V, and 70 V. A photo of the surface of the reflective film.

According to Fig. 6, it is understood that the particle diameter of the surface of the Ag/Bi (1 wt%) reflective film and the Ag/Bi (1.82 wt%) reflective film is smaller than the diameter of the granular material of the pure Ag reflective film. Therefore, it is estimated that the initial reflectance of the Ag/Bi (1 wt%) reflective film and the Ag/Bi (1.82 wt%) reflective film shown in Fig. 2 is worse than the initial reflectance of the pure Ag reflective film. One.

Moreover, as understood from FIG. 6, the particle diameter of the Ag/Bi (1 wt%) reflective film and the Ag/Bi (1.82 wt%) reflective film is accompanied by an increase in substrate bias (absolute value), compared with pure Ag. The granularity of the reflective film is large. This is considered to confirm that the initial reflectance of the Ag/Bi (1wt%) reflective film and the Ag/Bi (1.82wt%) reflective film shown in FIG. 3 is asymptotic to the initial reflectance of the pure Ag reflective film by the applied substrate bias Bias. The data of the effect.

<Relationship between substrate bias Bias and Bi concentration and film structure of reflective film>

Next, the result of examining the relationship between the substrate bias Bias and the concentration of Bi in the reflective film and the film structure of the reflective film will be described.

As the film structure of the reflective film, the Bi concentration distribution in the thickness direction of the reflective film was analyzed by X-ray photoelectron spectroscopy (XPS) in accordance with the measurement conditions shown in Table 1 below. Further, the measurement of the thickness of the ruthenium-containing film in the reflective film was carried out by using Rutherford Backscattering Spectrometry (RBS) according to the measurement conditions shown in Table 2 below. Further, a pure Ag reflective film, an Ag/Bi (1 wt%) reflective film, and an Ag/Bi (1.82 wt%) reflective film were selected as objects for measurement by XPS analysis and RBS analysis. Further, when each of the reflective films is deposited on the tantalum substrate 11, a voltage of |Bias| = 0 V, 30 V, and 100 V is selected as the substrate bias Bias (absolute value).

The analysis results of the reflective film obtained from XPS and RBS will be described below.

First, it was confirmed that both of the XPS analysis and the RBS analysis did not detect Bi in the pure Ag reflective film.

Next, at a voltage of |Bias|=0V, on the uppermost surface of the Ag/Bi (1 wt%) reflective film, Bi of about 3.1 at% concentration is a ruthenium oxide layer (Bi ₂ O ₃ layer) having a thickness of about 0.2 nm. Further, it was found that Bi at a concentration of about 0.3 at% at the interface between the Ag/Bi (1 wt%) reflection film and the ruthenium substrate 11 was detected as a metal Bi concentration layer having a thickness of about 0.25 nm. In addition, the thickness of the Bi ₂ O ₃ layer and the metal Bi concentration layer is detected by RBS, and the bulk density (bulk density×thickness) of Bi is used as a reference, and the bulk density used in the publication is used for simulation. The estimated value of the derivation.

Further, at a voltage of |Bias| = 0 V, on the uppermost surface of the Ag/Bi (1.82 wt%) reflective film, Bi of about 5.3 at% concentration is detected as a Bi ₂ O ₃ layer having a thickness of about 0.32 nm. At the interface between the Ag/Bi (1.82 wt%) reflective film and the ruthenium substrate 11, a Bi of about 0.9 at% concentration was detected by a metal Bi concentration layer having a thickness of about 0.26 nm.

Further, at a voltage of |Bias|=30 V, on the uppermost surface of the Ag/Bi (1.82 wt%) reflective film, Bi of about 3.6 at% was detected as a Bi ₂ O ₃ layer having a thickness of about 0.2 nm. At the interface between the Ag/Bi (1.82 wt%) reflective film and the ruthenium substrate 11, a Bi of about 3.1 at% concentration was detected by a metal Bi concentration layer having a thickness of about 1.45 nm.

Further, at a voltage of |Bias|=100 V, on the uppermost surface of the Ag/Bi (1.82 wt%) reflective film, Bi of about 0.8 at% concentration was detected by a Bi ₂ O ₃ layer having a thickness of about 0.04 nm. At the interface between the Ag/Bi (1.82 wt%) reflective film and the ruthenium substrate 11, a concentration of about 0.8 at% of Bi was detected by a metal Bi concentration layer (but the thickness could not be measured).

When the results of the analysis described above are summarized, it is confirmed that the Bi concentration layer is confirmed on the uppermost surface of the Ag/Bi (1 wt%) reflective film and the Ag/Bi (1.82 wt%) reflective film and the interface with the ruthenium substrate 11. The Bi concentration and thickness of the layers are varied depending on the substrate bias Bias. For example, as understood from the above analysis results, if the substrate bias Bias is sequentially added in the order of |Bias|=0V, 30V, 100V, Bi ₂ O ₃ present on the uppermost surface of the Ag/Bi (1.82 wt%) reflective film. The Bi concentration in the layer is reduced in the order of about 5.3 at%, about 3.6 at 23%, and about 0.8 at%, and the thickness is reduced in the order of about 0.32 nm, about 0.2 nm, and about 0.04 nm. This Bi ₂ O ₃ layer is presumed to serve as a barrier layer to contribute to the improvement of the environmental resistance of the reflective film. Conversely, if the film thickness of the Bi ₂ O ₃ layer is too thick, the initial reflectance of the reflective film is lowered. Bad effects. Therefore, it is considered that the effect of improving the initial reflectance of the Ag/Bi (1.82 wt%) reflection film can be exhibited by the moderate control of the substrate bias Bias. Similarly, it is considered that the control effect of the reflectance change amount of the Ag/Bi (1.82 wt%) reflective film can be exhibited by the moderate control of the substrate bias Bias.

As described above, according to the vacuum film forming apparatus 100 and the vacuum film forming method of the present embodiment, the initial reflectance can be reached and composed of pure Ag by appropriately adjusting the Bi bias of the substrate bias Bias and the Ag/Bi material 13. The reflective film is approximately the same level, and a reflective film excellent in environmental resistance composed of the Ag/Bi material 13 can be deposited on the ruthenium substrate 11.

In particular, by setting the substrate bias Bias to a range of 50 V or more and 70 V or less, and setting the Bi concentration of the Ag/Bi material 13 to 0.5 wt%, an initial reflection of the reflective film can be obtained in the entire visible light band. A reflective film having a rate (45° absolute reflectance) of approximately 94% or more equivalent to that of a pure Ag reflective film, and a reflection film having a reflectance change of 1.0% or less by a high-temperature and high-humidity environment is suitable. By.

Further, heretofore, as the vacuum film forming apparatus 100, an ion plating apparatus which accelerates the particles of the Ag/Bi material 13 and vapor-deposited on the tantalum substrate 11 is exemplified, and the present technology, in addition to such an ion plating apparatus, It can be applied to, for example, a sputtering apparatus.

From the above description, various modifications and other embodiments of the present invention will be apparent to those skilled in the art. Therefore, the above description is to be construed as illustrative only, and is provided for the purpose of the embodiments of the invention. The details of construction and/or function may be varied substantially without departing from the spirit of the invention.

In the vacuum film forming apparatus of the present invention, the reflectance at the initial stage of substrate deposition is approximately the same as that of the reflective film made of pure Ag, and the material is made of a material containing yttrium in silver, and is excellent in environmental resistance. The vacuum machine for membranes is useful.

11. . .矽 substrate

12. . . Substrate

13. . . Ag/Bi material

15. . . Hearth

17. . . Plasma gun

18. . . Permanent magnet

19. . . Covered member

20. . . Vacuum tank

20a. . . Vent

20b. . . Electron beam passage hole

20e. . . internal

100. . . Vacuum film forming device V1 bias DC power supply V2 gun DC power supply

Fig. 1 is a view showing an example of the configuration of the inside of a vacuum film forming apparatus according to an embodiment of the present invention.

Fig. 2 is a graph showing the initial reflectance of a reflective film made of an Ag/Bi material and the reflectance of a reflective film made of pure Ag in the visible light band.

Fig. 3 is a graph showing the initial reflectance of a reflective film made of an Ag/Bi material in comparison with the reflectance of a reflective film made of pure Ag in the visible light band.

4 is a bar graph showing the correlation between the amount of change in reflectance caused by the Ag/Bi (1.82 wt%) reflective film in a high temperature and high humidity environment and the substrate bias applied to the substrate in the visible light band. .

Fig. 5 is a view showing a correlation between a change amount of reflectance caused by a high-temperature and high-humidity environment and a concentration of Bi, which is a reflection film composed of an Ag/Bi material in a visible light band with a substrate bias voltage set to 0V. The long bar chart of the relationship.

Fig. 6 is a view showing the observation results of the surface of a reflective film obtained by a scanning electron micromirror (FE-SEM).

Fig. 7 is a view showing the principle of measurement of a spectrophotometer which evaluates the absolute reflectance of the reflective film at 45°.

Claims (7)

A vacuum film forming apparatus comprising: a vacuum chamber capable of internal decompression; a substrate device for holding a substrate in the vacuum chamber; and a bias power source for applying a predetermined bias voltage to the substrate; a material having a silver-coated reflective film material; and a material releasing mechanism for releasing the material from the material to the substrate and ionizing the material upon release of the material; The kinetic energy of the ionized material is deposited on the substrate by the bias voltage, and the reflectance of the reflective film is adjusted according to the bias voltage and the amount of the germanium added. The vacuum film forming apparatus of claim 1, wherein the material is a hearth containing the material, and the material releasing mechanism has a plasma gun, and the plasma gun releases the material in the hearth. The electron beam is heated and evaporated, and the material evaporated is ionized by the plasma generated by the electron beam. A vacuum film forming apparatus according to the first aspect of the invention, wherein the absolute value of the bias voltage is adjusted to be 50 V or more and 70 V or less when the vacuum chamber is grounded. The vacuum film forming apparatus of claim 1, wherein the amount of the niobium added is adjusted to about 0.5% by weight. A vacuum film forming method, wherein a substrate is disposed in a substrate in a vacuum chamber, and a material in the vacuum chamber is disposed on a material for a reflective film in which silver is added, and the vacuum chamber is depressurized, and the substrate is externally added. Biasing, when the material is released to the substrate, by ionizing the material, the kinetic energy of the material is increased by the bias, and a reflective film composed of the material is deposited on the substrate. The reflectance of the reflective film is adjusted in accordance with the bias voltage and the concentration of the crucible. A vacuum film forming method according to claim 5, wherein the absolute value of the bias voltage is adjusted to 50 V or more and 70 V or less when the vacuum chamber is grounded. The vacuum film forming method of claim 5, wherein the amount of the cerium added is adjusted to about 0.5% by weight.