JP2015105398A - Film forming device and film forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inject ion to an object member with uniform ion flux, when a film is formed on the object member by using plasma.SOLUTION: When the film is formed on the object member, plasma is formed from a first direction of treatment space surrounding the object member. The plasma is formed from a second direction different from the first direction of the treatment space, at delayed timing when the plasma is formed from the first direction. The film is formed on the object member by injecting ion to the object member by applying a pulse voltage on the object member after the start of forming the plasma from the first direction, and forming plasma from the second direction.

Description

  The present invention relates to a film forming apparatus and a film forming method for forming a film on a processing target member using plasma.

  In recent years, in order to form a film on a three-dimensional solid member, a technique using a plasma ion implantation method is known. In the plasma ion implantation method, ions in plasma are made to collide with the surface of a processing target member to which a high-voltage pulse voltage is applied, and ions are implanted into the surface of an object. Compared to a conventional ion beam, it is excellent in that a film can be formed even with a member having a complicated three-dimensional shape.

  In an ion implantation apparatus (Patent Document 1) using a plasma ion implantation method that has been conventionally known, a processing target member is supported in a suspended state in a processing space by a support device, and a high voltage pulse power supply is supported on the processing target member. Apply high voltage pulse. On the other hand, in a state where the solid raw material is melted by the cathode body and the solid raw material melt is held, discharge is performed between the cathode body and the anode body provided above the cathode body to generate plasma from the solid raw material melt. Ions generated by the generation of the plasma are attracted to the member to be processed to which the high voltage pulse is applied, and ions are implanted into the member to be processed.

Japanese Patent No. 4069199

  The ion implantation apparatus can form a film even if the member to be processed has a three-dimensional shape. However, when the size of the processing target member having a three-dimensional shape is large and the shape of the member is complicated, it is difficult to form a film on all parts of the processing target member. Even if the film can be formed on all parts of the member to be treated, it is difficult to keep the components of the film constant. For example, when a diamond-like carbon film is formed on the surface of the member to be treated, the hydrogen content in the film varies depending on the location. Such fluctuations depend on the uneven distribution of the energy and density of ions to be implanted. That is, when ions are implanted, the ion flux that is the flow of ions toward the member to be processed varies depending on the location.

  Therefore, the present invention has an object to provide a film forming apparatus and a film forming method capable of injecting ions with a uniform ion flux into a processing target member when a film is formed on the processing target member using plasma. And

One embodiment of the present invention is a film forming apparatus that forms a film on the surface of a processing target member using plasma. The device is
A processing vessel surrounding the processing space in which the processing target member is arranged;
A plurality of plasma generating elements provided on a plurality of different outer surfaces of the processing vessel;
A high frequency power supply for supplying power to the plurality of plasma generating elements;
A DC power source that outputs a voltage for applying a pulse voltage to the target member;
The power supplied to at least one of the plurality of plasma generating elements is the power supplied to other plasma generating elements other than the at least one plasma generating element, with respect to the preceding timing of the pulse voltage applied to the member to be processed. And a control unit that varies the preceding timing with respect to the pulse voltage.

  At this time, it is preferable that the control unit raises the pulse voltage after completion of the power supplied first among the power supplied to the plurality of plasma generating elements.

  In addition, it is preferable that the control unit raises the pulse voltage during or after the application of the latest power to be supplied to the plurality of plasma generating elements.

  Furthermore, the plurality of plasma generating elements include a first plasma generating element provided on a ceiling wall surface of the processing container and a plurality of second plasma generating elements provided on a side wall surface of the processing container. Is preferred.

  At this time, it is preferable that power is supplied to each of the second plasma generation elements at the same timing and for the same period.

  The processing container has a cylindrical shape with a circular or polygonal cross section, and the second plasma generating element is disposed on the side wall surface of the processing container at the same position in the longitudinal direction of the cylindrical shape. It is preferable to be provided so as to surround the target member.

  Each of the plasma generation elements is preferably a plasma generation electrode plate to which power is supplied from one end and the other end is grounded.

  The plasma generation element includes a first electrode plate that is a first plasma generation element provided on a ceiling wall surface of the processing container, and a plurality of second plasma generation elements provided on a side wall surface of the processing container. A second electrode plate, wherein the controller supplies power to an electrode plate located closest to a power supply end of the first electrode plate among the second electrode plates, Of the second electrode plates, it is preferable to supply power so as to be larger than the power supplied to the electrode plate located closest to the ground end of the first electrode plate.

Another aspect of the present invention is a film forming method for forming a film on the surface of a processing target member using plasma. The method is
Forming plasma from a first direction of a processing space surrounding the processing target member;
Forming plasma from a second direction different from the first direction of the processing space by delaying the timing to form plasma from the first direction;
After the plasma formed from the first direction and the plasma formed from the second direction are started, a pulse voltage is applied to the processing target member to cause the processing target member to generate the processing space by the plasma. And forming a film on the member to be treated by injecting ions produced from the gas inside.

  According to the film forming apparatus and the film forming method described above, ions can be implanted into the processing target member with a uniform ion flux.

It is a figure explaining the schematic apparatus structure of the film forming apparatus of this embodiment. (A)-(d) is a timing chart which shows the timing of the electric power supplied to the plasma production | generation element of the film forming apparatus shown in FIG. 1, and the timing of the pulse voltage applied to a process target member. (A) is a diagram showing an example of a result of measurement by X-ray photoelectron spectroscopy of a film of diamond-like carbon, (b) is of sp ³ hybrid orbital and sp ² hybrid orbital for the energy of ions incident on the film It is a figure which shows the change of a ratio. It is a figure which shows the change of the component of a film with respect to the timing of the application to the electrode plate of the pulse voltage performed after the production | generation of plasma is complete | finished. It is a figure which shows the change of the component of the film | membrane with respect to the level of the pulse voltage applied to an electrode plate. It is a figure explaining the production | generation of the plasma in the film forming apparatus shown in FIG. It is a figure which shows an example of the measurement result of the electron density in the plasma with respect to the electric power supplied to the plasma production element using the electrode plate of this embodiment. It is a figure explaining arrangement | positioning of the electrode plate for plasma generation of the membrane | film | coat formation apparatus shown in FIG. (A), (b) is a figure explaining the electron density in the plasma produced | generated by an electrode plate.

  Hereinafter, the film forming apparatus and the film forming method of the present invention will be described in detail. FIG. 1 is a diagram for explaining a schematic apparatus configuration of a film forming apparatus 10 according to an embodiment of the present invention.

A film forming apparatus 10 shown in FIG. 1 is an apparatus that forms a film on the surface of a processing target member 11 using plasma.
The film forming apparatus 10 includes a processing container 12, plasma generating elements 14a, 14b, 14c, high frequency power supplies 16a, 16b, 16c, a DC (direct current) power supply 18, a timing control unit 20, switch elements 22a, 22b, 22c and 22d are mainly provided.

  The processing container 12 is made of a material such as aluminum and creates a processing space inside. The processing vessel 12 is provided with an introduction pipe 23 for introducing a gas that is a raw material gas for forming a film and serves as a plasma generation gas, and further, an exhaust pipe 25 is provided. The introduction pipe 23 is connected to a gas source 27 of source gas, and the exhaust pipe 25 is connected to an exhaust device 29. The processing container 12 is configured so that the processing space can be maintained in a reduced pressure state of 1 to 100 Pa. A processing target member 11 is disposed in a processing space surrounded by the processing container 12.

  The plasma generating element 14 a is provided on the outer surface of the ceiling wall of the processing container 12. The plasma generation elements 14b and 14c are provided on the outer surface of the side wall of the processing container 12, and the plasma generation element 14b and the plasma generation element 14c are provided on the wall surfaces facing each other. Each of the plasma generation elements 14a, 14b, and 14c is connected to the switch elements 22a, 22b, and 22c via a matching box (not shown). In the embodiment shown in FIG. 1, plasma generation electrode plates (hereinafter referred to as electrode plates) are used as the plasma generation elements 14a to 14c. Hereinafter, reference numerals 14a, 14b, and 14c of the plasma generating elements are used as reference numerals of the electrode plates.

Insulating members 24a, 24b, and 24c are provided around the electrode plates 14a, 14b, and 14c to insulate them from the partition walls of the processing vessel 12. On the other hand, dielectrics 26a, 26b, and 26c are provided on the side of the electrode plates 14a, 14b, and 14c facing the processing space to cover the electrode plates 14a, 14b, and 14c. For example, a quartz plate is used for the dielectrics 26a, 26b, and 26c. The reason why the dielectrics 26a, 26b, and 26c are provided is to prevent the electrode plates 14a, 14b, and 14c from being corroded by the generated plasma and efficiently supply energy to the plasma.
The electrode plates 14a, 14b, and 14c are metal plate materials, for example, copper plates. Of the surfaces of the electrode plates 14a, 14b, and 14c, the main surface having the largest area is arranged to face the processing space. The electrode plates 14a, 14b, and 14c extend in one direction, one end in the extending direction is a power supply end to which power is supplied, and the other end is grounded to be a ground end. Each of the electrode plates 14a, 14b, and 14c is connected to the high-frequency power sources 16a, 16b, and 16c via the switch elements 22a, 22b, and 22c. The high frequency power supplies 16a, 16b, and 16c output a high frequency (for example, 13.56 MHz) in a range of 1 to 100 MHz, for example. Therefore, when power is supplied to one end of the electrode plates 14a, 14b, 14c, a current flows along the main surfaces of the electrode plates 14a, 14b, 14c, and a high-frequency magnetic field is formed in the processing space by the current, Plasma is formed by this magnetic field. The switch elements 22a, 22b, and 22c control power supply ON / OFF according to instructions from a timing control unit 20 described later.

  In the present embodiment, electrode plates 14a, 14b, and 14c are used as plasma generating elements. The electrode plates 14a, 14b, and 14c generate plasma in a processing space by generating a high-frequency magnetic field with a flowing current, and form an electric field by a conventional parallel plate electrode or an electromagnetic wave by resonance of an antenna. It differs from the method of generating plasma using it. In the system of this embodiment using an electrode plate, when the supplied power is the same, the electron density in the generated plasma is higher than in other systems. This embodiment has an electron density in plasma that is one digit higher than that using, for example, parallel plate electrodes. For this reason, the sheath thickness of the plasma formed around the processing target member 11 is reduced. Therefore, even when different surfaces of the processing target member 11 face each other and are close to each other, ion implantation can be performed on the two adjacent surfaces. In this respect, the plasma generation method of the present embodiment using an electrode plate is effective in forming a film on the processing target member 11 having a three-dimensional shape.

  The DC power supply 18 outputs a DC (direct current) voltage. The DC power source 18 is connected to the switch element 22d. The switch element 22d outputs a pulse voltage in accordance with an instruction from the timing control unit 20 described later, and applies the pulse voltage to the processing target member 11. That is, the DC power source 18 provides a voltage for applying a pulse voltage to the processing target member 11. The voltage is, for example, 0.5 to 4 kV. The processing target member 11 is supported by a base support member provided in the processing container 12 and disposed in the processing space. The processing target member 11 is connected to the DC power source 18 via the switch element 22d. Therefore, when the switch element 22d outputs a pulse voltage according to the instruction of the timing control unit 20, the processing target member 11 is applied with the pulse voltage and is charged by the applied voltage. Thereby, the ion implantation to the process target member 11 is started.

  The timing control unit 20 sets the preceding timing of the power supplied to the electrode plate 14a to the pulse voltage applied to the processing target member 11, and the pulse voltage applied to the processing target member 11 of the power supplied to the electrode plates 14b and 14c. The electric power is supplied to the electrode plates 14a, 14b, and 14c in a different manner from the preceding timing.

2A to 2D are timing charts showing the timing of power supplied to the electrode plates 14a, 14b, and 14c of the film forming apparatus 10 and the timing of the pulse voltage applied to the processing target member 11. FIG.
The power supply period to the electrode plates 14a, 14b, and 14c is, for example, 10 to 500 μs. For example, power of 100 to 3000 W is supplied to the electrode plates 14a, 14b, and 14c. On the other hand, the pulse width (negative voltage) of the pulse voltage (negative voltage) applied to the processing target member 11 is, for example, 0.1 to 500 μs, and a voltage of, for example, 0.5 to 4 kV is applied.

  As described above, in this embodiment, the generation timing of the plasma preceding the pulse voltage is changed according to the electrode plate. By changing this timing, the energy of ions incident on the processing target member 11 changes. Thus, the inventors of the present application have found that the components of the film formed on the processing target member 11 change, and have come up with the present invention.

Fig.3 (a) is a figure which shows the example of the measurement result of the film | membrane of the diamond-like carbon obtained using X-ray photoelectron spectroscopy (XPS). In FIG. 3A, a film formed by raising the pulse voltage during plasma formation, a film formed by raising the pulse voltage 50 μs after the completion of plasma formation, and a pulse voltage formed 200 μs after the completion of plasma formation. XPS measurement data is shown for a film formed by startup. Further, FIG. 3 (a) shows XPS data of a known carbon-based material (carbon oxidizing material, diamond structural material composed of sp ³ hybrid orbital, graphite structural material composed of sp ² hybrid orbital). Has been.
According to FIG. 3A, the position of the peak value of the XPS data shifts in the direction of the peak value of the graphite structure material composed of sp ² hybrid orbits as the timing of supplying the pulse voltage from the start of plasma formation is delayed. I can see that
On the other hand, FIG. 3 (b), with respect to ion energy incident on the film shows a known graph showing the change in the ratio of sp ³ hybrid orbital and sp ² hybrid orbitals. As can be seen from this graph, the ratio of sp ³ hybrid orbitals to sp ² hybrid orbitals varies depending on the energy of ions incident on the film. Therefore, as shown in FIG. 3 (a), the fact that the position of the peak value of the film changes by changing the timing of supplying the pulse voltage from the start of plasma formation is changed by changing the timing of the pulse voltage. It can be considered that the energy of ions incident on the film changes.

FIG. 4 is a diagram showing that the components of the formed film are different when the timing of applying the pulse voltage to the electrode plate after the plasma generation is completed is changed. The horizontal axis in the figure is the time from the end of plasma generation until the pulse voltage is applied. The vertical axis in the figure is a value calculated from the ratio of the luminescence intensity of carbon atoms and hydrogen atoms evaluated using glow discharge emission spectrometry, and is an index representing the hydrogen content. In the example of FIG. 4, in order to form diamond-like carbon as a film on the processing target member, the source gas is C ₂ H ₂ , the processing space is 1 Pa of source gas atmosphere, and a high frequency of 13.56 MHz is applied to one electrode. Electric power was supplied at 500 W for 50 μs, and a pulse voltage of −2 kV was applied to the processing target member 11 at a repetition period of 1 kHz for 20 μs.
As shown in FIG. 4, it can be seen that the content of the hydrogen component in the diamond-like carbon is changed by changing the timing of applying the pulse voltage to the electrode plate after the plasma generation is completed. The hydrogen content affects the film density and film hardness, and the higher the hydrogen content, the lower the film density and the lower the film hardness.
Thus, by changing the timing of applying the pulse voltage to the electrode plate after the plasma generation is completed, the ion energy is changed, and the film density and film hardness are changed.

  FIG. 6 is a view for explaining generation of plasma in the film forming apparatus 10.

  The timing control unit 20 can also raise a pulse voltage to be applied to the processing target member 11 while supplying power larger than the power supplied to the electrode plate 14a to the electrode plates 14b and 14c. In this case, since plasma is generated when the pulse voltage is raised, ion implantation into the processing target member 11 can be realized using ions having high ion energy in the plasma. Therefore, even if the ion flux performed using the ions generated in the plasma Pa is still non-uniform, the ion density in the plasmas Pb and Pc generated during the pulse voltage is high, so the uniform ion flux Can be realized. Further, the timing control unit 20 can also start up a pulse voltage to be applied to the processing target member 11 after supplying power larger than the power supplied to the electrode plate 14a to the electrode plates 14b and 14c (after the supply is completed). In this case, the pulse voltage may be raised within 0 to 300 μsec after the supply of power to the electrode plates 14b and 14c is completed.

  By repeating the cycle with the supply of high-frequency power to the electrode plate and the application of the pulse voltage to the processing target member 11 at the timing as shown in FIGS. Increase the thickness. As a result, a film is formed on the surface of the processing target member 11 by deposition of ions or radicals generated from the ions at the time of plasma generation, and the film and further the processing target member are applied by applying a pulse voltage to the processing target member 11. 11 is implanted to determine the surface modification of the processing target member 11 and the components of the film.

  As in the present embodiment, an electrode plate that is a plurality of plasma generation elements includes an electrode plate 14 a (first plasma generation element) provided on the outer surface of the ceiling wall of the processing container 12, and the side walls of the processing container 12. By including the electrode plates 14 b and 14 c (second plasma generating elements) provided on the outer surface, the coating can be reliably formed on the upper surface and the side surface of the processing target member 11.

  As shown in FIGS. 2B and 2C, it is preferable to supply power to each of the electrode plates 14b and 14c at the same timing for the same period. If the timing of the power supplied to the electrode plates 14b and 14c with respect to the pulse voltage applied to the processing target member 11 is different between the electrode plates 14b and 14c, a uniform ion flux cannot be realized.

  As one embodiment, the processing vessel 11 has a cylindrical shape with a circular or polygonal cross section, and an electrode plate (second plasma generating element) provided on the side wall surface of the processing vessel 11 is a processing vessel. It is preferable that it is provided on the side wall surface of the container 11 so as to surround the processing target member 11 at the same position in the longitudinal direction of the cylindrical shape. FIG. 8 shows the preferred embodiment. In FIG. 8, in addition to the electrode plates 14b and 14c, the electrode plates 14e and 14d on the periphery of the surface on the side wall surface of the cylindrical processing vessel 11, and also the other surface on the side wall surface not shown. Two electrode plates are provided. The number of electrode plates provided on the periphery of the side wall surface of the processing vessel 11 is not particularly limited. These electrode plates are preferably supplied with power for the same period at the same timing.

  As in this embodiment, each of the plasma generating elements is a plasma generating electrode plate that is supplied with power from one end and grounded at the other end. Therefore, the apparatus configuration is simpler than that of a conventional parallel plate electrode. Since the plasma density is high, the sheath thickness is reduced, and a film can be reliably formed even for a processing target member having a complicated three-dimensional shape.

Since a current flows in one direction in the electrode plate 14a, a large difference in potential occurs between the power supply end and the ground end of the electrode plate 14a. 9A and 9B are diagrams for explaining the electron density in the plasma generated by the electrode plate 14a. The result shown in FIG. 9B is a measurement result of the electron density of plasma generated in the processing space into which C ₂ H ₂ (1 Pa) is introduced. At this time, 1 kW high-frequency power (13.56 MHz) is applied to the power supply end of the electrode plate 14a, and the multiple ends are grounded. As shown in FIG. 9B, the electron density is high on the ground side, and the electron density is low on the supply end. The reason for this is not clear, but the plasma generated based on the magnetic field generated by the current is dominant at the grounded end (plasma derived from the current), whereas the supply end is generated by a high voltage. This is thought to be due to the dominant plasma (plasma derived from voltage) being dominant. This is because, on the supply end side, since the voltage is high, the energy of electrons is low on the supply end side and it is considered that high-density plasma is difficult to be generated. Therefore, the ion density and ion energy distribution in the plasma are also different on the ground end side and the supply end side. Therefore, in consideration of the non-uniform ion density and energy distribution, the power supplied to the electrode plate located closest to the power supply end of the electrode plate 14a out of the electrode plates 14b and 14c is the electrode plate 14b, In order to form a uniform ion flux, it is preferable to supply power so as to be larger than the power supplied to the electrode plate located closest to the ground end of the electrode plate 14a. As shown in FIGS. 2B and 2C, the power supplied to the electrode plate 14c located on the power supply end side (see FIG. 2C) is applied to the electrode plate 14b located on the ground end side. It is larger than the supplied power (see FIG. 2B).

In such a film forming apparatus 10, the raw material gas is supplied into the processing chamber 11 that has been evacuated into the processing container 11, and maintained at a low pressure of 1 Pa, for example. Alternatively, the processing space is in a reduced pressure state of the raw material gas atmosphere by exhausting while continuously supplying the raw material.
In this state, plasma is formed from the direction of the ceiling of the processing space surrounding the processing target member 11 (from the first direction) by supplying high-frequency power to the electrode plate 14a. Further, after the plasma is formed, the high frequency power is supplied to the electrode plates 14b and 14c by delaying the plasma in the direction of the side wall of the processing space (from the second direction) to the supply timing of the high frequency power to the electrode plate 14a. As a result, plasma is formed.
A pulse voltage is applied to the member 11 to be processed after the plasma formed from the direction of the ceiling and the plasma formed from the direction of the side wall are started. Thus, ions are implanted into the processing target member 11 to form a film on the processing target member 11. By such processing, the ion energy of ions implanted into the processing target member 11 can be made uniform regardless of the location, and the component of the ions can be made uniform regardless of the location.

  As described above, the film forming apparatus and the film forming method of the present invention have been described in detail. However, the present invention is not limited to the above-described embodiments and examples, and various improvements and modifications can be made without departing from the gist of the present invention. Of course it is also good.

DESCRIPTION OF SYMBOLS 10 Film formation apparatus 11 Process target member 12 Processing container 14a, 14b, 14c Plasma production | generation element (electrode plate)
16a, 16b, 16c High-frequency power supply 18 DC power supply 20 Timing control units 22a, 22b, 22c, 22d Switch element 23 Inlet pipe 25 Exhaust pipe 27 Gas source 29 Exhaust device

Claims (9)

A film forming apparatus that forms a film on the surface of a processing target member using plasma,
A processing vessel surrounding the processing space in which the processing target member is arranged;
A plurality of plasma generating elements provided on a plurality of different outer surfaces of the processing vessel;
A high frequency power supply for supplying power to the plurality of plasma generating elements;
A DC power source that outputs a voltage for applying a pulse voltage to the target member;
The power supplied to at least one of the plurality of plasma generating elements is the power supplied to other plasma generating elements other than the at least one plasma generating element, with respect to the preceding timing of the pulse voltage applied to the member to be processed. And a control unit for making the timing different from the preceding timing with respect to the pulse voltage.   2. The film forming apparatus according to claim 1, wherein the control unit raises the pulse voltage after the power supplied first among the power supplied to the plurality of plasma generating elements is finished.   3. The film forming apparatus according to claim 1, wherein the control unit raises the pulse voltage during or after application of the latest power to be supplied to the plurality of plasma generation elements. .   The plurality of plasma generation elements include a first plasma generation element provided on a ceiling wall surface of the processing container and a plurality of second plasma generation elements provided on a side wall surface of the processing container. The film formation apparatus of any one of 1-3.   The film forming apparatus according to claim 4, wherein electric power is supplied to each of the second plasma generation elements at the same timing and at the same time. The processing vessel has a cylindrical shape with a circular or polygonal cross section,
The said 2nd plasma production | generation element is provided in the same position of the longitudinal direction of the said cylindrical shape on the side wall surface of the said process container so that the said process target member may be enclosed. Film forming device.   The film forming apparatus according to claim 1, wherein each of the plasma generation elements is a plasma generation electrode plate to which electric power is supplied from one end and the other end is grounded. The plasma generation element includes a first electrode plate that is a first plasma generation element provided on a ceiling wall surface of the processing container, and a plurality of second plasma generation elements provided on a side wall surface of the processing container. A second electrode plate,
The control unit supplies power supplied to an electrode plate located closest to a power supply end of the first electrode plate among the second electrode plates. The film formation apparatus of any one of Claims 1-3 which supplies electric power so that it may become large with respect to the electric power supplied to the electrode plate located nearest to the earthing | grounding end of 1 electrode plate. A film formation method for forming a film on the surface of a processing target member using plasma,
Forming plasma from a first direction of a processing space surrounding the processing target member;
Forming plasma from a second direction different from the first direction of the processing space by delaying a timing for forming plasma from the first direction;
After the plasma formed from the first direction and the plasma formed from the second direction are started, a pulse voltage is applied to the processing target member to cause the processing target member to generate the processing space by the plasma. And a step of forming a film on the member to be processed by injecting ions produced from the gas in the film.

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