JP4071020B2 - Photocatalyst layer forming method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to the technical field of functional thin films, and particularly relates to a technique for manufacturing a photocatalytic device having an oxide film and a photocatalytic function.
[0002]
[Prior art]
Titanium oxide (Ti0₂) Is widely known for its self-cleaning property and hydrophilicity due to photoactivity.₂At present, environmental pollution is becoming serious, and development of products using environmental protection is urgently required as environmental purification and maintenance products.
The code | symbol 110 of FIG. 10 has shown an example of the photocatalyst apparatus of a prior art. The photocatalyst device 110 includes a substrate 111 and a photocatalyst layer 115 disposed on the substrate 111.
[0003]
The photocatalyst layer 115 is made of titanium oxide. When the photocatalyst layer 115 is irradiated with ultraviolet rays, the titanium oxide in the photocatalyst layer 115 is activated and the contaminants attached to the surface of the photocatalyst layer 115 are decomposed.
As a result, the surface of the photocatalyst layer 115 is always kept clean and has a very high hydrophilicity. Therefore, the surface of the photocatalyst device 110 is hardly soiled and water droplets are not easily attached.
[0004]
As a film formation method of the photocatalyst layer 115, for example, a sol-gel method in which a coating solution of titanium oxide is applied to the surface of the substrate 111 and dried is generally used. Adhesiveness is poor, and the photocatalyst layer 115 may peel from the substrate 111 in some cases.
[0005]
When metal photocatalyst layer 115 is formed by sputtering using metal titanium or titanium oxide as a target, photocatalyst layer 115 having high adhesion to substrate 111 can be obtained. However, in order to produce anatase-type titanium oxide having high photocatalytic activity by sputtering, it is necessary to perform sputtering while heating the substrate 111 to 300 ° C. or higher, or to heat the substrate 111 to 300 ° C. or higher after sputtering. There is.
[0006]
Therefore, the material of the substrate 111 is limited to a material having high heat resistance such as glass, and it is difficult to form a strong titanium oxide thin film having high photocatalytic activity on the surface of the substrate 111 made of plastic or the like. there were.
[0007]
[Problems to be solved by the invention]
The present invention was created to solve the above-mentioned disadvantages of the prior art. The purpose of the present invention is to provide photocatalytic activity not only on heat-resistant materials but also on the surface of substrates made of non-heat-resistant materials such as plastics. It is to form a high photocatalyst layer.
[0008]
[Means for Solving the Problems]
The inventors focused on sputtering as a thin film formation method of titanium oxide, and as a result of intensive studies, the crystallinity of titanium oxide formed by the sputtering method depends on the incident angle of the sputtered particles that first reach the substrate. I understood that it was influenced.
As a result of further studies by the present inventors, when the incident angle, which is the angle formed between the projection direction of the first incident sputtered particles and the normal of the substrate surface, is 86 ° or less, a fine anatase type It has been found that a crystal structure is formed.
[0009]
  The invention according to claim 1 made based on such knowledge,While moving the film formation object in the vacuum chamber, the surface of the film formation object is made of SiO. ₂ A photocatalyst layer forming method for forming an undercoat layer and a titanium oxide photocatalyst layer, wherein the undercoat layer is formed in the vacuum chamber, and then the film formation target is not heated on the undercoat layer. Sputtered particles are incident on the surface at an incident angle of 86 ° or less, a titanium oxide layer is formed on the surface of the undercoat layer, and the sputtered particles are incident on the titanium oxide layer without heating the film formation target. In the photocatalyst layer forming method, the titanium oxide layer is grown and the photocatalyst layer formed of an anatase type titanium oxide layer is formed on the undercoat layer.
  The invention according to claim 2The photocatalyst layer forming method according to claim 1, wherein the titanium oxide layer is grown so that the film thickness of the photocatalyst layer is 300 nm or more.
[0010]
The present invention is configured as described above, and in the film forming apparatus of the present invention, among the sputtered particles emitted from the target toward the substrate, those having an incident angle of 86 ° or more to the substrate are blocked by the shielding plate. It has come to be.
Therefore, when the sputtered particles are titanium oxide, the incident angle of the sputtered particles incident on the substrate is limited to 86 ° or less at the initial stage of thin film formation, and the titanium oxide crystal grown thereafter is anatase type. Become.
[0011]
According to the present invention, by limiting the incident angle of the sputtered particles first incident on the substrate to 86 ° or less, an anatase-type titanium oxide thin film can be obtained without heating the substrate. The resin material is not limited to heat resistant materials such as metals, and various resin materials can be used.
[0012]
Among the resin materials, polycarbonate resin is excellent in transparency and impact resistance, and is widely used for compact discs (CD), architectural windows, automobile windows, soundproof walls on highway roads, and the like. The application of such plastics will enable the development of new photocatalytic products and can be expected to contribute to further expansion of applications.
[0013]
When a resin is used as the material constituting the substrate, a silicon dioxide thin film, which is an undercoat film, is formed on the surface of the substrate, and a titanium oxide thin film is formed on the undercoat film. Since the titanium thin film is firmly fixed to the substrate, the strength of the resulting photocatalytic device is increased.
Since the film forming apparatus includes at least two film forming sources, the titanium oxide thin film and the thin film formed by stacking the titanium oxide thin films can be continuously formed without exposing the substrate to the atmosphere.
[0014]
In the case of a so-called in-line type film forming apparatus that performs film formation while moving the substrate below the film forming source at a predetermined speed, if the film forming speed at each film forming source is low, the work efficiency becomes extremely poor. In the present invention, since the two electrodes are alternately placed at a negative potential and the target is sputtered, the sputtering efficiency is high, and the film formation rate is fast enough to be practically used as an in-line film forming apparatus.
Further, if the potentials of the first and second electrodes are switched at an intermediate frequency of 10 kHz or more and 100 kHz or less, the film formation rate becomes as fast as when a DC voltage is applied to the target.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an example of the film forming apparatus of the present invention and a process of manufacturing a photocatalytic apparatus using the film forming apparatus will be described in detail.
Reference numeral 1 in FIG. 1 shows an example of a film forming apparatus of the present invention.
[0016]
The film forming apparatus 1 has a carry-in chamber 6, a film forming chamber 5, and a carry-out chamber 7. An evacuation system 25 is disposed outside the film formation chamber 5, and the inside of the film formation chamber 5, the carry-in chamber 6, and the carry-out chamber 7 are individually evacuated by the vacuum evacuation system 25. ing.
[0017]
The film forming chamber 5 includes a vacuum chamber 8, a substrate moving device, and a plurality of film forming sources 21 to 23. Here, the number of film forming sources 21 to 23 is three, and they are arranged in a horizontal row on the ceiling side inside the vacuum chamber 8.
The substrate moving device has a substrate mounting table 9 and a motor (not shown). The carry-in chamber 6 and the carry-out chamber 7 are respectively connected to the vacuum chamber 8 via an entrance-side gate valve 38 and an exit-side gate valve 39, and a substrate to be described later enters the carry-in chamber 6 from the door 48 of the carry-in chamber 6. A substrate moving mechanism (not shown) provided in the carry-in chamber 6 is carried into the vacuum chamber 8 through the entrance-side gate valve 38 and the substrate is placed on the substrate platform 9. It has come to be.
[0018]
Next, when the motor is started, the substrate mounting table 9 moves to a position immediately below each film forming source 21 to 23, and the thin film is formed by sputtered particles emitted from each film forming source 21 to 23, as will be described later. After being formed, it moves to the vicinity of the exit side gate valve 39 and is carried into the carry-out chamber 7 from the vacuum chamber 8 through the exit-side gate valve 39 by a substrate transfer mechanism (not shown) provided in the carry-out chamber 7. Then, the film is taken out from the door 49 of the carry-out chamber 7 to the outside of the film forming apparatus 1.
[0019]
The structure of the film forming sources 21 to 23 will be described in detail. Each film forming source 21 to 23 includes two cathode electrodes 31 to 36, targets 41 to 46, and two shielding plates 51 to 56, respectively.
The two cathode electrodes 31 to 36 are directly above the position where the substrate mounting table 9 moves, and are arranged along the moving direction of the substrate mounting table 9. The cathode electrodes 31 to 36 are horizontal, and one target 41 is provided for each cathode electrode 31 to 36 on the surface of each cathode electrode 31 to 36 facing the substrate mounting table 9. -46 are arranged.
[0020]
On one side of the cathode electrodes 31 to 36 opposite to the targets 41 to 46, one magnet 61 to 67 for generating a magnetic field is arranged for each cathode electrode 31 to 36. The film forming sources 21 to 23 have container-shaped electrostatic shields 71 to 73, and one cathode electrode 31 to 36 and one magnet 61 to 67 are accommodated together in the electrostatic shield 71 to 73. The electrodes 31 to 36 adjacent to each other, and the electrodes 31 to 36 and the shielding plates 51 to 56 are blocked by a partition wall formed of a part of the electrostatic shields 71 to 73, and discharge from the electrodes 31 to 36 is performed. Is to be blocked.
[0021]
Power sources 75 to 77 are disposed outside the vacuum chamber 8, and the cathode electrodes 31 to 36 are connected to the power sources 75 to 77, respectively. The vacuum chamber 8 is connected to the ground potential, and the two cathode electrodes 31 to 36 in one film forming source 21 to 23 are connected to the other cathode electrode when a negative voltage is applied to one cathode electrode. Is applied with a ground voltage. Therefore, while a negative voltage is applied to one of the two targets 41 to 46 and sputtering gas ions having a positive charge are incident and sputtered, the other target is not sputtered, but rather has a negative charge. When a dielectric thin film is formed on the target surface, the charge-up of the dielectric thin film is eliminated.
[0022]
The two shielding plates 51 to 56 are arranged in the vertical direction so as to be separated from each other, and the cathode electrodes 31 to 36 are arranged between the two shielding plates 51 to 56.
The upper ends of the shielding plates 51 to 56 are positioned near the ceiling, and the cathode electrodes 31 to 36 and the targets 41 to 46 are positioned between the upper ends of the two shielding plates 51 to 56.
[0023]
The shielding plates 51 to 56 are respectively positioned on the entrance side and the exit side when the substrate mounting table 9 moves directly below the film forming sources 21 to 23. The lengths of the shielding plates 51 to 56 are such that when a substrate described later passes below the shielding plates 51 to 56 together with the substrate mounting table 9, a predetermined distance is provided between the lower ends of the shielding plates 51 to 56 and the substrate surface. Has come to exist.
[0024]
When the angle formed between the jumping direction of the sputtered particles jumping out from the targets 41 to 46 and the vertical direction is defined as the popping angle, and the popping angle is defined as 0 ° or more and 90 ° or less, the one having a large popping angle adheres to the shielding plates 51 to 56. However, those with a small pop-out angle are radiated to the bottom wall side of the vacuum chamber 8.
[0025]
Assuming that the angle formed by the sputtered particles incident on the substrate and the vertical direction is the incident angle, when the substrate is horizontally disposed, the pop-out angle and the incident angle are in a complex angle relationship, and thus are equal to each other.
Assuming that the range in which the sputtered particles are emitted to the bottom wall side of the vacuum chamber 8 is the film forming range, a thin film is formed on the substrate surface while the substrate described later passes through the film forming range.
[0026]
Here, since the distance between the film forming sources 21 to 23 is sufficiently separated so that the film forming ranges do not overlap, the components of the thin film formed by one film forming source are the other film forming sources. It does not mix with the thin film components of the source.
A sputtering gas source 26 and a reactive gas source 27 are arranged outside the vacuum chamber 8, and a sputtering gas (in this case, argon gas, Ar) from the sputtering gas source 26 and a reactive gas (from the reactive gas source 27 ( Here, oxygen gas, O₂) Is supplied into the vacuum chamber 8 by the gas introduction system 28.
[0027]
Next, a process of forming a thin film on a film formation target using the film forming apparatus 1 as described above will be described.
Reference numeral 16 in FIG. 4A indicates a substrate which is a film formation target. The substrate 16 includes a support 11 and a hard coat layer 12 formed on the surface of the support 11. Here, the support 11 is made of a rectangular polycarbonate resin film having a thickness of 5 mm, a length of 25 mm, a width of 75 mm, or a larger size.
[0028]
The hard coat layer 12 is made of a resin harder than the resin constituting the support 11 (for example, a cured product of a thermosetting resin or a cured product of an ultraviolet curable resin), and the support 11 is sputtered as described later. In this process, it is protected by the hard coat layer 12 so as not to be damaged.
[0029]
Next, a process of forming a film on the substrate 16 using the film forming apparatus 1 as shown in FIG. 1 will be described.
First, the targets 41 to 46 made of an inorganic material are attached to the cathode electrodes 31 to 36 of the film forming sources 21 to 23. Here, the cathode electrodes 31 and 34 of the film forming source 21 adjacent to the carry-in chamber 6 and the cathode electrodes 33 and 36 of the film forming source 23 adjacent to the carry-out chamber 7 are targets 41, 44, 43, made of silicon, respectively. 46, and targets 42 and 45 made of titanium metal were attached to the cathode electrodes 32 and 35 of the film forming source 22 in the middle.
[0030]
The planar shape of the targets 41 to 46 was a rectangular shape having a long side of 1090 mm and a short side of 380 mm.
FIG. 2 shows a case in which a plurality of substrates 16 are successively subjected to film formation using the film formation apparatus 1. The substrate subjected to film formation by the film formation source 21 on the carry-in chamber 6 side, and the film formation The substrate film-formed by the film-forming source 22 adjacent to the source 21 is sent to the next film-forming source 22 and 23, respectively, and at the same time, the substrate film-formed by the film-forming source 23 on the carry-out chamber 7 side. The unprocessed substrate is newly carried into the vacuum chamber 8 from the carry-in chamber 6.
[0031]
FIG. 2 is a view focusing on the unprocessed substrate 16 carried in from the carry-in chamber 6. The substrate 16 carried into the vacuum chamber 8 is placed on the substrate platform 9 with the hard coat layer 12 facing upward. Placed horizontally.
The substrate 16 is moved horizontally together with the substrate mounting table 9 toward the lower side of the film forming sources 21 to 23 at a predetermined speed (here, 20 cm / min). When the substrate 16 passes through the deposition range of the deposition source 21 adjacent to the carry-in chamber 6, silicon dioxide (SiO 2), which is an oxide of silicon, is formed on the surface of the hard coat layer 12 of the substrate 16.₂) Is formed.
[0032]
Reference numeral 17 in FIG. 4B indicates the substrate on which the undercoat layer 13 made of a silicon dioxide thin film is formed. The thickness of the undercoat layer 13 is about 0.1 μm or more and 2 μm or less.
FIG. 3 shows a state immediately after the substrate 17 in that state is further sent in the movement direction, and the front end of the substrate 17 in the movement direction reaches the end of the film formation range of the next film formation source 22.
[0033]
Assuming that the area where the targets 51 to 56 are sputtered is an erosion area, the sputtered particles that reach the end of the film formation area jump out from the position farthest from the shielding plate 53 in the erosion area and jump out. Angle θ₁Is the smallest.
In the erosion region, the distance between the farthest position from the entrance side shielding plate 53 and the shielding plate 53 is w, and the height from the lower end of the shielding plate 53 to the surfaces of the targets 42 and 45 is h. Then, the pop-out angle θ₁Is tan^-1(W / h).
[0034]
In the present invention, the distance w and the height h are tan^-1(W / h) ≦ 86 °.
As described above, when the substrate 17 is horizontal, the incident angle θ of the sputtered particles₂Is the projection angle θ₁Is incident on the substrate 17 of sputtered particles that jump out of the targets 42 and 45 and go to the entrance side shielding plate 53.₂Is 86 ° or less.
[0035]
As described above, the surface of the substrate 17 is SiO.₂The undercoat layer 13 is formed, and sputtered particles made of titanium oxide incident on the surface of the undercoat layer 13 at an incident angle of 86 ° or less adhere to the surface, and crystals grow by the sputtered particles. A thin film consisting of begins to form.
[0036]
When the substrate 17 is sent toward the lower side of the targets 42 and 45, the pop-out angle θ is smaller than that of the first sputtered particle.₂The sputtered particles reach the substrate 17, and the thin film grows by sputtered particles incident at a smaller angle on the surface of the initially formed thin film.
[0037]
The distance from the lower end of the exit side shielding plate 54 to the surfaces of the targets 42 and 45 is not particularly limited, but sputtered particles having an incident angle exceeding 86 ° are incident on the substrate 17 after passing through the shielding plate 54. However, since the crystal type is already determined by the first incident sputtered particles, and the sputtered particles that enter later grow along the axis, the crystal type is affected by the sputtered particles incident at a large incident angle. I do not receive it.
[0038]
Reference numeral 18 in FIG. 4C denotes a substrate in a state in which a titanium oxide thin film (photocatalyst layer) 14 having a predetermined thickness is formed through the film formation region.
Further, when the substrate 18 is sent to the film forming source 23 on the carry-out chamber 7 side and passed through the film forming range of the film forming source 23, the surface of the photocatalyst layer 14 has a predetermined film thickness (2.5 nm to 20 nm). A silicon dioxide thin film (topcoat layer) 15 is formed, and a photocatalytic device 10 as shown in FIG. 4D is obtained.
[0039]
The photocatalyst device 10 is sent to the vicinity of the gate valve 39 on the outlet side together with the substrate mounting table 9, the gate valve 39 on the outlet side is opened, the photocatalytic device 10 is carried out from the vacuum chamber 8 to the carry-out chamber 7, and the gate valve on the outlet side If the door 49 of the carry-out chamber 7 is opened after closing 39, the photocatalytic device 10 can be taken out of the film formation chamber 7.
[0040]
In this photocatalytic device 10, the incident angle θ of the sputtered particles that first enter the substrate 17.₂Is limited to 86 ° or less, fine anatase-type crystals are formed in the photocatalyst layer 14, and the photocatalytic activity is very high compared to amorphous or rutile titanium oxide.
[0041]
Further, since the photocatalyst layer 14 is formed on the surface of the undercoat layer 13, the support 11 and the hard coat layer 12 are not eroded by the photocatalytic activity of the photocatalyst layer 14.
The topcoat layer 15 formed on the surface of the photocatalyst layer 14 has a function of maintaining its hydrophilicity even when the photocatalyst device 10 is left in a place where it does not receive light.
In this photocatalyst device 10, since the support 11 is made of a resin such as polycarbonate resin, it is easy to process and reduce the weight of the photocatalyst device 10.
[0042]
【Example】
The photocatalyst device 10 produced in the above steps was taken as Example 1, and photographing of an electron micrograph of the photocatalyst layer 14 of Example 1 and X-ray diffraction of the photocatalyst layer 14 were performed.
The film formation conditions of the photocatalyst layer 14 are as follows: the degree of vacuum in the vacuum chamber 8 is 12 mTorr, and the partial pressure P of oxygen gas_O2And argon partial pressure P_ArAnd the ratio is P_Ar: P_O2= 40: 60, input power density of targets 41 to 46 is 2.7 W / cm₂The film thickness of the obtained photocatalyst layer 14 was 1.1 μm. Tan^-1The angle θ obtained by h / w was 86 °.
[0043]
An electron micrograph of the photocatalyst layer 14 is shown in FIG. Note that the interval between the graduations in the lower right of FIG. 5 is 300 nm.
As can be seen from FIG. 5, in this photocatalyst layer 14, primary fine particles having a diameter of about 10 nm grow to form secondary particles having a size of about 100 nm × 50 nm. A structure is formed.
[0044]
Electron micrographs were also taken for a commercial vehicle mirror (photocatalyst device) on which a 270 nm-thick photocatalyst layer was formed by EB vapor deposition and a photocatalyst device manufactured by the sol-gel method. In the photocatalyst device, the fine structure as described above was not observed in the photocatalyst layer.
[0045]
That is, since the photocatalyst layer 14 formed by the film forming method of the present invention has a larger specific surface area and a larger contact area with the object to be decomposed than the conventional one, the ability to decompose the object to be decomposed is high. I guess that.
FIG. 6 shows an X-ray diffraction pattern of the photocatalyst layer 14. The horizontal axis in FIG. 6 indicates the diffraction angle (2θ), and the vertical axis indicates the intensity.₁₀₁Indicates a peak derived from the [101] orientation plane of titanium oxide, and the symbol P in FIG.₂₀₀Indicates a peak derived from the [200] orientation plane.
[0046]
It is known that when anatase type titanium oxide is subjected to X-ray diffraction, peaks derived from the [101] orientation plane and the [200] orientation plane are observed.
As is clear from FIG. 6, in the photocatalyst layer 14 formed in the above process, the peak P derived from the [101] orientation plane and the [200] orientation plane.₁₀₁, P₂₀₀It can be seen that the photocatalytic layer 14 is composed of anatase-type titanium oxide.
[0047]
Tan^-1When the photocatalyst layer was formed by using the film forming apparatus 1 having an angle obtained by w / h exceeding 86 °, an anatase type crystal structure could not be confirmed.
Next, the photocatalyst devices 10 of Examples 2 to 4 were manufactured in the above-described steps except that the film formation conditions for forming the photocatalyst layer 14 were changed.
[0048]
<Example 2>
After forming the hard coat layer 12 under the same conditions as in Example 1, the photocatalyst layer 14 having a film thickness of 330 nm was formed under the conditions that the power applied to the target was 15 kW and the film formation time was 2.7 hours. A topcoat layer 15 having a thickness of 10 nm was formed on the surface of the photocatalyst layer 14 to obtain the photocatalyst device 10 of Example 2.
[0049]
<Example 3>
After forming the hard coat layer 12 under the same conditions as in Example 1, the photocatalyst layer 14 having a film thickness of 240 nm is formed under the conditions that the power applied to the target is 20 kW and the film formation time is 1.3 hours. A top coat layer 15 having a film thickness of 20 nm was formed on the surface 14, and the photocatalytic device 10 of Example 3 was obtained.
[0050]
<Example 4>
A photocatalytic device 10 of Example 4 was obtained under the same conditions as in Example 3 except that the topcoat layer 15 was not formed.
The “photocatalytic activity” test shown below was performed using the photocatalyst device 10 of Examples 2 to 4 and the photocatalyst device of the comparative example.
In this case, as the photocatalytic device of the comparative example, the same vehicle loading mirror as that used for taking the electron micrograph was used.
[0051]
[Photocatalytic activity]
First, 4 mW / cm on the surface of the topcoat layer 15 or the photocatalyst layer 14 of the photocatalyst device 10.²Initialization is performed by irradiating with UV light having a wavelength of 350 nm for 48 hours. Next, the photocatalytic device 10 was charged with methylene blue (C₁₆H₁₈N_ThreeS ・ Cl ・ 3H₂O) After being immersed in an aqueous solution for 1 hour, it was lifted from the methylene blue aqueous solution and dried in the dark for 30 minutes to obtain a measurement sample.
[0052]
The photocatalytic performance of this measurement sample is measured under the trade name “PCC-1” which is a photocatalyst checker manufactured by Vacuum Riko Co., Ltd.
The method has a strength of 1 mW / cm on the surface of the measurement sample on the topcoat layer 15 side.²The amount of change in absorbance of light having a wavelength of 650 nm was measured over time.
In other words, the photocatalyst layer 14 exerts strong oxidizing power by UV light irradiation, and the methylene blue is decomposed and gradually becomes transparent by measuring the change in absorbance over time. A larger value indicates higher photocatalytic activity.
[0053]
FIG. 7 is a graph showing changes in absorbance measured in the “photocatalytic activity” test. The vertical axis represents ΔABS (absorbance), and the horizontal axis represents time (minutes).
Reference L in FIG.₂~ L_FourShows a graph obtained for the photocatalyst device 10 of Examples 2 to 4, the symbol L in the figure_FiveThese are the graphs obtained about the photocatalyst apparatus of the comparative example. As is clear from FIG. 7, Examples 2 to 4 show a large decrease in absorbance as compared with the comparative example, and it can be seen that the photocatalytic activity is high when the photocatalytic layer 14 is formed by the film forming method of the present invention.
[0054]
When Examples 3 and 4 are compared, even when the photocatalyst layer 14 having the same film thickness is formed, the photocatalytic activity is higher when the topcoat layer 15 is formed than when the topcoat layer 15 is not formed. It is high.
Further, when Example 2 and Example 3 are compared, it can be seen that the photocatalytic activity becomes very high when the film thickness of the photocatalyst layer 14 is 300 nm or more.
[0055]
The case where the support 11 is made of polycarbonate resin has been described above. However, the present invention is not limited to this, and various resins such as acrylic resin and polyester resin can be used as the resin constituting the support 11. Things can be used.
Moreover, the material which comprises the support body 11 is not limited to resin, Inorganic materials, such as a metal and glass, can also be used.
[0056]
Examples of the application of the photocatalytic device 10 according to the present invention include, for example, an automatic military headlight reflector / instrument cover, a cable car window, a road reflector, a solar cell cover, a computer display, a bathroom equipment member, and a kitchen equipment member. Etc.
The film thickness of the photocatalyst layer 14 is not particularly limited, but if the film thickness is 150 nm or more, the photocatalytic activity is sufficiently high in practical use.
In addition, the photocatalyst layer 14 can be exposed on the surface of the photocatalyst device 10 without directly forming the photocatalyst layer 14 on the surface of the support 11 or forming the topcoat layer 15.
[0057]
Although the case where argon gas (Ar) is used as the sputtering gas has been described above, the present invention is not limited to this, and various inert gases such as xenon gas (Xe) can be used.
Although the case where oxygen is used as the reaction gas has been described above, the present invention is not limited to this, and various gases can be used as long as they react with the inorganic material constituting the target. For example, when nitrogen is used as the reaction gas, a nitride film made of a nitride of an inorganic material constituting the target can be obtained.
[0058]
Although the case where two shielding plates 51 to 56 are installed in each film forming source 21 to 23 has been described above, the present invention is not limited to this. The shielding plates 51 to 56 only need to be installed at a position before the film formation target faces the targets 41 to 46, and the targets 41 to 46 can be surrounded by three or more shielding plates.
The shape of the shielding plate is not particularly limited. For example, the shielding plate may be formed in a cylindrical shape, and the electrodes 31 to 36 and the targets 41 to 46 may be disposed inside the cylindrical shape.
[0059]
The case where the shielding plate is arranged near the ceiling has been described above, but the present invention is not limited to this. FIG. 9 shows another example of the shielding plates 96a to 96d. The code | symbol 95 of FIG. 9 has shown the film-forming source, and this film-forming source 95 has the four shielding plates 96a-96d.
Among the shielding plates 96a to 96d, the two shielding plates 96a and 96b are vertically arranged in the vicinity of the ceiling in the vacuum chamber 8. Of these two shielding plates 96a and 96b, one shielding plate 96a is the mounting table 9. Is located on the entrance side when passing through the film forming source 95, and the other shielding plate 96b is located on the exit side thereof.
[0060]
The other two shielding plates 96c and 96d are vertically arranged on the bottom wall side in the vacuum chamber 8, and one shielding plate 96c is located on the entrance side when the mounting table 95 passes through the film formation source, The shielding plate 96d is located on the exit side.
The shielding plates 96a and 96b arranged on the ceiling side and the shielding plates 96c and 96d arranged on the bottom wall side are separated from each other by a predetermined distance, and the mounting table 9 on which the substrate 16 is placed is the shielding plate 96a on the ceiling side. 96b and the shielding plates 96c and 96d on the bottom wall side can pass therethrough.
[0061]
The case where the substrate 16 is transported together with the substrate mounting table 9 has been described above, but the present invention is not limited to this. For example, even if the film formation sources 21 to 23 are moved with respect to the substrate 16. good. In addition, rotating film formation in which the substrate rotates around the film forming source may be used.
The number of film forming sources 21 to 23 is not particularly limited, and the number is determined depending on the purpose of film formation. Further, when forming a thin film of the same material, such as the top coat layer 15 or the undercoat layer 13, the film may be formed with the same film formation source as in the film forming apparatus 90 shown in FIG. it can.
[0062]
The purpose of film formation is not limited to the titanium oxide thin film, and even in the case of other oxide films, if the film formation apparatus 1 having the above structure is used, a crystal structure can be obtained by the same low temperature film formation. Referring to FIG. 8, this film forming apparatus 90 has a film forming chamber 5 and one carry-in / out chamber 91, and two film forming sources 21 and 22 are provided in the vacuum chamber 8 of the film forming chamber 5. Is arranged.
Of the two film forming sources 21 and 22, the targets 41 and 44 of the film forming source 21 adjacent to the carry-in / out chamber 7 are made of silicon, and the targets 42 and 45 of the other film forming source 22 are made of titanium. .
[0063]
In order to manufacture the photocatalyst device 10 using this film forming apparatus 90, the substrate 16 is carried into the vacuum chamber 8 through the carry-in / out chamber 91, and is passed under the film forming sources 21 and 22 together with the substrate mounting table 9. After the undercoat layer 13 and the photocatalyst layer 14 are formed, the substrate 18 is returned to the carry-in / out chamber 91 side, and again passes under the film forming source 21 adjacent to the carry-in / out chamber 7. A top coat layer 15 made of the same material as is formed. The photocatalytic device 10 with the top coat layer 15 formed is taken out of the film forming device 90 through the carry-in / out chamber 91 again.
[0064]
【The invention's effect】
According to the present invention, a photocatalytic layer having high photocatalytic activity can be formed without heating the substrate. In addition, since the film formation rate by the film formation source is high and a plurality of substrates can be processed continuously, the production efficiency is also high. The application range of the present invention is a photocatalytic film (TiO₂) As well as other oxide films (ITO, ZnO)₂, Ta₂O_Five, SiO₂The same effect can be obtained for low-temperature crystallization in film formation.
[Brief description of the drawings]
FIG. 1 illustrates an example of a film formation apparatus according to the present invention.
FIG. 2 is a diagram for explaining the first half of a process for producing a photocatalytic device by the film forming method of the present invention.
FIG. 3 is a diagram for explaining the latter half of the process of manufacturing a photocatalytic device by the film forming method of the present invention.
FIGS. 4A to 4D are cross-sectional views of steps for manufacturing a photocatalytic device.
FIG. 5 is an electron micrograph of a photocatalyst layer formed by the film forming method of the present invention.
Fig. 6 X-ray diffraction pattern of photocatalyst layer
FIG. 7 is a graph showing the photocatalytic activity of the photocatalytic device.
FIG. 8 is a diagram for explaining another example of the film forming apparatus of the present invention.
FIG. 9 is a diagram for explaining another example of a shielding plate.
FIG. 10 is a diagram for explaining a conventional photocatalytic device.
[Explanation of symbols]
1 …… Deposition system
8 ... Vacuum tank
16-18 …… Board
21 to 23, 95 ... Deposition source
31-36 …… Electrode (cathode electrode)
41-46 …… Target
51-56, 96a-96b …… Shielding plate

Claims (2)

While moving the film formation object in the vacuum chamber, the surface of the film formation object is made of SiO. ₂ A photocatalyst layer forming method for forming an undercoat layer and a titanium oxide photocatalyst layer,
  After forming the undercoat layer in the vacuum chamber,
  Sputtering particles are incident on the undercoat layer at an incident angle of 86 ° or less on the undercoat layer without heating the film formation target, forming a titanium oxide layer on the undercoat layer surface,
  Sputtering particles are incident on the titanium oxide layer without heating the film formation target, the titanium oxide layer is grown, and the photocatalytic layer composed of an anatase-type titanium oxide layer is formed on the undercoat layer. Photocatalyst layer formation method. The photocatalyst layer forming method according to claim 1, wherein the titanium oxide layer is grown so that the film thickness of the photocatalyst layer is 300 nm or more.

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