JP6109775B2 - Film forming apparatus and film forming method - Google Patents

Description

  The present invention relates to a film forming apparatus and a film forming method.

  2. Description of the Related Art A film forming apparatus that forms a transparent conductive film on a film formation object by reactive plasma vapor deposition is known (see, for example, Patent Document 1). The film forming apparatus disclosed in Patent Document 1 forms a transparent conductive film on a base film formed on a substrate. An example of the transparent conductive film is an indium tin oxide (ITO: compound of indium oxide and tin oxide) film.

JP 2002-30423 A

  As one of the base films on which the transparent conductive film is formed, there is an optical adjustment film having a film containing silicon oxide. When this optical adjustment film is employed as a base film on which a transparent conductive film is formed, the transparent conductive film may be formed on a film containing silicon oxide.

  For reasons such as productivity or controllability of film thickness distribution, it is conceivable that a film containing silicon oxide is formed by reactive sputtering. Film formation by reactive sputtering can increase the film formation speed and is excellent in controllability of film thickness distribution. However, when a film containing silicon oxide is formed by reactive sputtering and a transparent conductive film is formed on the film by reactive plasma deposition, the specific resistance value of the formed transparent conductive film may increase. There is.

  Therefore, an object of the present invention is to provide a film forming apparatus and a film forming method capable of forming a transparent conductive film in which an increase in specific resistance value is suppressed.

  The inventors of the present invention have intensively studied a configuration capable of forming a transparent conductive film in which an increase in specific resistance value is suppressed. As a result, when the present inventors formed a film containing silicon oxide by high frequency sputtering and formed a transparent conductive film on the film by reactive plasma deposition, the ratio of the formed transparent conductive film The present inventors have come up with the present invention by finding the fact that an increase in resistance value is suppressed.

  That is, a film forming apparatus according to the present invention includes a first film forming unit for forming a first base film containing silicon oxide by reactive sputtering, and a second base film containing silicon oxide on the first base film. A second film forming unit for forming a film by high frequency sputtering, a third film forming unit for forming a transparent conductive film on the second underlayer by reactive plasma deposition, and first, second, and third film forming units. A transport unit that transports the film formation target between the units.

  The film forming method according to the present invention includes a first film forming step of forming a first base film containing silicon oxide by reactive sputtering, and a first film containing silicon oxide on the first base film by high frequency sputtering. A second film forming step of forming a second base film, and a third film forming step of forming a transparent conductive film on the second base film by reactive plasma deposition.

  ADVANTAGE OF THE INVENTION According to this invention, the film-forming apparatus and the film-forming method which can form the transparent conductive film in which the increase in specific resistance value was suppressed can be provided.

It is a figure for demonstrating the cross-sectional structure of the optical element which concerns on embodiment of this invention. It is a schematic block diagram of the film-forming apparatus which concerns on embodiment of this invention. It is a flowchart which shows the content of the film-forming method which concerns on this embodiment. It is a figure which shows the test conditions in the Example and comparative example of this invention. It is a figure which shows the measurement result of the sheet resistance value in the Example and comparative example of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

  FIG. 1 is a diagram for explaining a cross-sectional configuration of an optical element E1 according to the present embodiment. The optical element E1 is used for, for example, a touch panel, a solar cell, or an organic EL illumination used for an electronic device such as a portable terminal.

As shown in FIG. 1, the optical element E1 is provided on the substrate B. The material of the substrate B is, for example, glass or a silicon wafer. On the substrate B, a first base film M1 is formed. The first base film M1 contains silicon oxide. The material of the first base film M1 is silicon oxide (SiOx: for example, SiO ₂ ). The first base film M1 functions as, for example, an optical adjustment film.

A second base film M2 is formed on the first base film M1. The second base film M2 contains silicon oxide. The material of the second base film M2 is silicon oxide (SiOx: for example, SiO ₂ ). A transparent conductive film M3 is formed on the second base film M2. The transparent conductive film M3 is a TCO (Transparent Conductive Oxide) film. The material of the transparent conductive film M3 is a material containing indium oxide as a composition, for example, a metal oxide such as indium oxide without doping elements, indium tin oxide, indium tungsten oxide, or indium zinc oxide. Two or more of these metal oxides may be combined. The thickness of the transparent conductive film M3 may be set to, for example, about 5 to 35 nm, but is not limited to this value. The substrate B in a state where the first base film M1, the second base film M2, and the transparent conductive film M3 are not formed, the substrate B in a state where the first base film M1 is formed, and the first base film M1 The substrate B on which the second base film M2 is formed corresponds to a film formation target 10 to be described later.

(Deposition system)
Here, with reference to FIG. 2, the film-forming apparatus used when manufacturing the optical element E1 mentioned above is demonstrated. FIG. 2 is a schematic configuration diagram of the film forming apparatus 1 according to the embodiment of the present invention.

  The film forming apparatus 1 generates a plasma in a dilute argon atmosphere in a vacuum, and bombards positive ions in the plasma against the film forming material (targets 3 and 4) to eject the atoms of the film forming material and form a film. An apparatus for depositing on the object 10 to form a film and an apparatus for ionizing a film deposition material (tablet 5) using the generated plasma and depositing on the film to be deposited object 10 Contains. The film deposition apparatus 1 includes a vacuum chamber 2, a power source 6, a transport roller 11 (transport section) that transports the film formation target 10, and a control section 30 that controls the film deposition apparatus 1. . The power source 6 supplies power to electrodes (not shown) provided in the vacuum chamber 2. The plurality of electrodes respectively hold the targets 3 and 4. Each of the targets 3 and 4 is electrically connected to the power source 6.

  The vacuum chamber 2 is adjacent to the sputtering chamber 7A in which sputtering is performed, the exhaust chamber 8 adjacent to the upstream side of the sputtering chamber 7A, the vapor deposition chamber 7B adjacent to the downstream side of the sputtering chamber 7A, and the downstream side of the vapor deposition chamber 7B. And a vent chamber 9 to be used. A film formation target 10 is accommodated in the vacuum chamber 2. A conveyance roller 11 is provided in the vacuum chamber 2. The conveyance roller 11 can arrange the film formation target 10 and can convey the arranged film formation target 10 in a predetermined conveyance direction A. As a result, the film formation target 10 is transported in the transport direction A by the transport roller 11.

  The targets 3 and 4 are flat plate members made of a film forming material or a part of the film forming material (composition material). A cylindrical member may be used as the targets 3 and 4. The targets 3 and 4 are arranged facing the film formation target 10 in the sputtering chamber 7A. The targets 3 and 4 are arranged along the transport direction A at a predetermined interval.

  A sputtering space C <b> 1 is formed between the target 3 and the film formation target 10. A sputtering space C <b> 2 is formed between the target 4 and the film formation target 10.

  The sputtering chamber 7 </ b> A includes a first film forming unit 71 and a second film forming unit 72. The substrate B is transported to the first film forming unit 71 as the film formation target 10 by the transport roller 11. The film formation target 10 conveyed to the first film formation unit 71 may be formed on the substrate B. The first film forming unit 71 forms a first base film M1 containing silicon oxide by reactive sputtering. The target 3 is a material made of silicon. A gas containing oxygen is introduced into the vacuum chamber 2 and the target 3 is sputtered to form a film containing silicon oxide.

  The substrate B on which the first base film M <b> 1 is formed is transported to the second film forming unit 72 as the film formation target 10 by the transport roller 11. The second film forming unit 72 forms a second base film M2 containing silicon oxide on the first base film M1 by high frequency sputtering. The target 4 is a material made of silicon oxide. A gas containing oxygen is introduced into the vacuum chamber 2 and the target 4 is sputtered to form a film containing silicon oxide.

  The vapor deposition chamber 7 </ b> B includes a third film forming unit 73. The substrate B on which the first base film M <b> 1 and the second base film M <b> 2 are formed is transported to the third film forming unit 73 as the film formation target 10 by the transport roller 11. The third film forming unit 73 includes a main hearth 41 that holds the tablet 5, a ring hearth 42 that is an auxiliary anode surrounding the main hearth 41 in a ring shape, and a plasma source 43 such as a plasma gun that irradiates the main hearth 41 with a plasma beam. And comprising. The third film forming unit 73 forms a transparent conductive film M3 on the second base film M2 by reactive plasma deposition. The tablet 5 is a material containing indium oxide as a composition, for example, indium tin oxide. The tablet 5 is disposed facing the film formation target 10 in the vapor deposition chamber 7B. The third film forming unit 73 generates plasma P by the plasma source 43 and heats and evaporates the tablet 5 held in the main hearth 41. At this time, the evaporant diffuses in the space C3 formed between the evaporation source (tablet 5) and the film formation target 10, so that the transparent conductive film M3 is formed by reactive plasma deposition.

  A film forming apparatus 1 is connected to each of a sputtering chamber 7A, a vapor deposition chamber 7B, an exhaust chamber 8, and a vent chamber 9, and is equipped with a turbo molecular pump (TMP) 12 for evacuating each chamber. , A gate valve 13 provided between the sputtering chamber 7A, the vapor deposition chamber 7B, the exhaust chamber 8 and the vent chamber 9, the inlet portion of the exhaust chamber 8, and the outlet portion of the vent chamber 9, the exhaust chamber 8 and the vent. And a dry pump 14 connected to each of the chambers 9.

  The film forming apparatus 1 includes an argon cylinder 16 filled with argon (Ar) gas as an inert gas, which is an atmospheric gas, and a gas that supplies the argon gas in the argon cylinder 16 into the sputtering chamber 7 at a predetermined flow rate. A mass flow controller (MFC) 17 which is a flow rate controller is provided. Note that xenon (Xe) or krypton (Kr) may be used as the atmospheric gas. The film forming apparatus 1 includes an oxygen cylinder 22 filled with oxygen gas, and a mass flow controller 21 that is a gas flow controller for supplying the oxygen gas in the oxygen cylinder 22 into the sputtering chamber 7A at a predetermined flow rate. Yes.

  Lines L 11, L 12, and L 13 for introducing argon gas into the vacuum chamber 2 are connected to the argon cylinder 16. A mass flow controller 17 is connected to the lines L11, L12, and L13. On the other hand, lines L21, L22, and L23 for introducing oxygen gas into the vacuum chamber 2 are connected to the oxygen cylinder 22. A mass flow controller 21 is connected to the lines L21, L22, and L23. The line L21 joins in the middle of the line L11. The exit end of the line L11 is disposed in the vicinity of the target 3. The line L22 joins in the middle of the line L12. The exit end of the line L12 is disposed in the vicinity of the target 4. The line L23 joins in the middle of the line L13. The exit end of the line L13 is disposed in the vapor deposition chamber 7B.

  The mass flow controllers 17 and 21 are electrically connected to the control unit 30. The control unit 30 controls the flow rate of argon gas and oxygen gas supplied to the vacuum chamber 2 by controlling the mass flow controllers 17 and 21. Thereby, the control unit 30 can adjust the oxygen concentration in the vacuum chamber 2.

  A heating unit 18 is arranged in the transport direction A on the back side in the vacuum chamber 2 facing the film thickness direction of the film formation target 10. The heating unit 18 indirectly heats the surface on which the film is formed by heating the back side of the film formation target 10. The heating unit 18 is a heater, and heat is transmitted to the substrate B by the heating unit 18. The heating unit 18 is provided in each of the sputtering chamber 7, the exhaust chamber 8, and the vent chamber 9. The attachment position in the vacuum chamber 2 is not particularly limited, and the heating unit 18 may be disposed anywhere as long as the film formation target 10 can be heated.

  The power source 6 is a power source for supplying power to the targets 3 and 4 to cause discharge. As shown in FIG. 2, the power source 6 includes an MF power source 61 and an RF power source 62. The MF power supply 61 is a high-frequency power supply that oscillates a frequency in the MF band. The MF power supply 61 and the target 3 are electrically connected. The MF power supply 61 applies a wave-like or rectangular wave-like voltage having a certain period to the target 3. The frequency of the MF power supply 61 is, for example, several tens of kHz.

  The RF power source 62 is a high frequency power source that oscillates a frequency in the RF band. The RF power source 62 and the target 4 are electrically connected. The RF power source 62 applies a wave-like or rectangular wave-like voltage having a certain period to the target 4. The frequency of the RF power source 62 is, for example, 13 to 41 MHz. A matching box 62a for impedance matching is provided.

  The control unit 30 controls the operation of the film forming apparatus 1. The control unit 30 is electrically connected to at least the power source 6, the conveyance roller 11, and the heating unit 18, and can control each component so as to satisfy predetermined film forming conditions. The control unit 30 controls the heating unit 18 so that the temperature of the film formation target 10 at the time of film formation becomes a temperature suitable for film formation. The control unit 30 controls the power source 6 so that the discharge power is suitable for film formation.

(Production method)
Here, a method MT1 as an example of a film forming method for forming the transparent conductive film M3 on the film forming object 10 by sputtering and reactive plasma deposition using the film forming apparatus 1 described above will be described. However, it is not limited to the film forming method according to the following description, and the procedure and processing conditions may be changed as appropriate. FIG. 3 is a flowchart showing the contents of the manufacturing method of the optical element E1 according to this embodiment.

  First, a step of forming the first base film M1 on the substrate B is executed (step S1: first film forming step). The process of step S <b> 1 is executed by the first film forming unit 71. In step S1, the first base film M1 is formed on one surface of the substrate B. The substrate B on which the first base film M1 is formed is transferred to the second film forming unit 72.

  Next, a step of forming the second base film M2 is executed (step S2: second film forming step). The process of step S <b> 2 is executed by the second film forming unit 72. In step S2, the second base film M2 is formed on the first base film M1 formed on the substrate B. The substrate B on which the second base film M2 is formed is transported to the third film forming unit 73.

  And the process of forming the transparent conductive film M3 is performed (step S3: third film forming process). The process of step S3 is executed by the third film forming unit 73. A transparent conductive film M3 is formed on the outermost surface of the second base film M2 formed on the substrate B.

  As described above, when steps S1 to S3 are completed, the process of manufacturing the optical element E1 having the transparent conductive film M3 formed on the surface is completed.

(Action / Effect)
Next, operations and effects of the film forming apparatus 1 and the film forming method according to the present embodiment will be described.

  According to the film forming apparatus 1 and the manufacturing method described above, the transparent conductive film M3 is not formed directly on the first base film M1 formed by the reactive sputtering method, but is formed by the high frequency sputtering method. The film is formed on the filmed second base film M2. Therefore, it is possible to form the transparent conductive film M3 in which the increase in specific resistance value is suppressed.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these Examples.

[Example 1]
As Example 1, an indium tin oxide film was formed as the transparent conductive film M3 using the film forming apparatus 1. FIG. 4 shows test conditions in the examples of the present invention and comparative examples. As shown in FIG. 4, the test conditions were as follows. As a material for the substrate B, silicon (Si) to which boron was added was used. The conveyance speed of the substrate B was 5 mm / sec. The substrate temperature during film formation was 180 ° C. The sizes of the targets 3 and 4 were all 100 mm × 1 m × 66 mm. The size of the tablet 5 was 30 mm × 40 mm in diameter.

  The first film forming unit 71 has a film forming pressure of 0.7 Pa. Argon gas was used as the atmospheric gas, and the flow rate of argon gas was 150 sccm. The flow rate of oxygen was 100 sccm. An AC power source was used as the power source. The input power was 12 kW at the MF band frequency, and the discharge voltage was -360V.

  The second film forming unit 72 had a film forming pressure of 0.7 Pa. The flow rate of argon gas was 200 sccm. The input power was 6 kW at the RF band frequency, and the discharge voltage was -450V.

  The third film forming unit 73 has a film forming pressure of 0.5 Pa. The flow rate of argon gas was 140 sccm. The flow rate of oxygen was 30 sccm. A DC power source was used as the power source. The current was 150 A and the discharge voltage was −60V.

  Under the conditions described above, the first base film M1, the second base film M2, and the transparent conductive film M3 were formed to obtain an optical element E1. The sheet resistance value of the formed transparent conductive film M3 was measured. The measurement results are shown in FIG. In this embodiment, the sheet resistance value was measured instead of the specific resistance value. The sheet resistance value is an amount representing the electric resistance value of a film having a thickness, and its unit is Ω. In order to avoid confusion with the electrical resistance value, the unit of the sheet resistance value was described as Ω / □ (see FIG. 5). The unit of the specific resistance value is Ω · m. For this reason, the sheet resistance value and the specific resistance value are amounts that can be converted into each other by considering the film thickness.

[Comparative Example 1]
The transparent conductive film was formed under the same conditions as in Example 1 except that the transparent conductive film was directly formed on the substrate B. That is, only the transparent conductive film was formed on the substrate B by reactive plasma deposition. The sheet resistance value of the transparent conductive film was measured in the same manner as in Example 1. The measurement results are shown in FIG.

[Comparative Example 2]
The transparent conductive film was formed under the same conditions as in Example 1 except that the transparent conductive film was directly formed by reactive plasma deposition on the first base film M1 formed by the reactive sputtering method. Filmed. That is, only the first base film M1 and the transparent conductive film were formed on the substrate B. The sheet resistance value of the transparent conductive film was measured in the same manner as in Example 1. The measurement results are shown in FIG.

[Evaluation]
Here, the measurement results of Example 1, Comparative Example 1, and Comparative Example 2 described above are evaluated. As shown in FIG. 5, it can be confirmed that the sheet resistance value of the transparent conductive film obtained in Example 1 is substantially the same as the sheet resistance value of the transparent conductive film obtained in Comparative Example 1. It was. It was confirmed that the sheet resistance value of the transparent conductive film obtained in Example 1 was lower than the sheet resistance value of the transparent conductive film obtained in Comparative Example 2.

  As described above, the specific resistance value of the transparent conductive film M3 formed on the second base film M2 formed by the high frequency sputtering method is directly formed on the base film formed by the reactive sputtering method. It was confirmed that the specific resistance value was smaller than that of the transparent conductive film. Therefore, it can be confirmed that by forming the transparent conductive film M3 on the second base film M2 formed by the high frequency sputtering method, the transparent conductive film M3 in which the increase in specific resistance value is suppressed is formed. It was. That is, it can be said that an increase in the specific resistance value of the transparent conductive film can be suppressed while the performance other than the specific resistance value (for example, adhesion to the substrate) is improved by providing the base layer.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to such embodiment at all, In the range which does not deviate from the summary of this invention, it can implement with a various aspect.

  The optical element E1 is not limited to the case where the first base film M1 is directly formed on the substrate B as in the above-described embodiment. For example, the first base film M1 may be formed by reactive sputtering on another film formation target formed on the substrate B.

  The film forming apparatus 1 is not limited to the inline type in which the film forming target 10 is formed while being transported in the vacuum chamber 2 as in the above-described embodiment, but may be a batch type.

  DESCRIPTION OF SYMBOLS 1 ... Film-forming apparatus, 10 ... Film formation object, 11 ... Conveyance roller (conveyance part), 71 ... 1st film-forming part, 72 ... 2nd film-forming part, 73 ... 3rd film-forming part, A ... Conveyance direction , B ... substrate, M1 ... first base film, M2 ... second base film, M3 ... transparent conductive film.

Claims (2)

A first film forming unit for forming a first underlayer containing silicon oxide by reactive sputtering;
A second film-forming part for forming a second base film containing silicon oxide on the first base film by high-frequency sputtering;
A third film forming unit for forming a transparent conductive film on the second underlayer by reactive plasma deposition;
A film forming apparatus comprising: a transfer unit configured to transfer a film forming object between the first, second, and third film forming units. A first film forming step of forming a first base film containing silicon oxide by reactive sputtering;
A second film forming step of forming a second base film containing silicon oxide on the first base film by high-frequency sputtering;
And a third film forming step of forming a transparent conductive film on the second base film by reactive plasma deposition.

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