JP2005044604A - Plasma treatment device and its treatment method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma treatment device and its treatment method in which a wide range and uniform plasma region is formed and the film forming area of a treating object can be expanded, and a film can be formed uniformly throughout the expanded film forming range. <P>SOLUTION: A vertical support shaft 25 of a steering coil 15a is engaged with a cylinder 26a of a drive mechanism 26 by a crank mechanism, and the vertical support shaft 25 is rotated in the horizontal direction by the reciprocating movement of the cylinder 26a. Thereby, the steering coil 15a is displaced in the width direction at a prescribed cycle against the medial axis direction E of plasma emission and the emitting direction of plasma emitted from a plasma source is changed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plasma processing apparatus and a processing method thereof, and more particularly to a plasma processing apparatus and a processing method thereof for forming a film on a substrate.
[0002]
[Prior art]
In a plasma processing apparatus such as a plasma CVD apparatus, a sputtering apparatus using plasma and an ion plating apparatus using plasma, plasma is generated by high frequency discharge such as RF discharge or microwave discharge, or by DC (direct current) discharge, Plasma is incident on an electrode arranged in accordance with a plasma source. In this case, the generated plasma is generally substantially cylindrical plasma (hereinafter referred to as cylindrical plasma), and the generated cylindrical plasma is incident on, for example, an electrode formed in a cylindrical shape.
[0003]
However, when cylindrical plasma is used, for example, in an ion plating apparatus, the plasma formation region is limited to a range of a cylindrical beam having a diameter of, for example, about 400 to 600 mm at the maximum. The region where the film-forming material particles evaporated from the substrate are exposed to plasma and activated is limited, and it is difficult to form a film uniformly on an object to be processed such as a large-area substrate. In other words, the plasma concentration in the space inside the chamber (vacuum vessel) is distributed, and the film-forming material particles that pass through the high plasma concentration region and the small plasma region have different ionization behavior and the flight trajectory of the ionized particles. The film formed by the film material particles adhering to the film formation object is not homogeneous and causes in-plane variation of the film formation object (see Patent Document 1).
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 8-100254
[Problems to be solved by the invention]
However, in the case of an apparatus using cylindrical plasma, even if the plasma distribution is controlled and optimized, it is difficult to form a uniform film over a large area because the plasma formation region does not expand greatly. There was a problem. Further, when a plurality of plasma sources are arranged, there is a problem that the apparatus configuration becomes complicated and the apparatus cost increases, and it is difficult to obtain a uniform plasma concentration distribution.
[0006]
Accordingly, the present invention has been made in view of the above problems, and forms a uniform plasma formation region over a wide range, enlarges the film formation region on the object to be processed, and forms a uniform film. An object of the present invention is to provide a plasma processing apparatus and a processing method thereof.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a plasma processing apparatus according to the present invention comprises a vacuum vessel, a plasma source that generates plasma connected to the vacuum vessel, and a film forming material disposed in the vacuum vessel. And an electrode portion to which the plasma is incident and a steering coil for guiding the plasma into the vacuum vessel, and the film forming material is formed on the object to be processed so as to face the electrode portion. In the plasma processing apparatus for forming a film, the plasma processing apparatus includes: a plasma region expanding means for expanding a plasma region generated by the plasma source by changing a substantial direction of the steering coil with respect to a central axis direction of the plasma emission from the plasma source. It is characterized by that.
[0008]
In this case, the electrode unit is disposed in a direction orthogonal to the plasma emission central axis direction of the plasma gun, the object to be processed is disposed at a position facing the electrode unit, and the plasma is It is configured to be bent from the direction of the plasma emission central axis and to be incident on the electrode portion to form a film on the object to be processed.
[0009]
With the above configuration of the present invention, a wide and uniform plasma formation region can be formed. Thereby, a film of uniform quality can be obtained in a wider film formation area than in the past.
[0010]
Further, in this case, the plasma region expanding means constitutes the steering coil, and controls a plurality of coil portions having different angles with respect to the plasma emission central axis direction and a magnetic field of the plurality of coil portions. It is preferable that the configuration is provided with means.
[0011]
With such a configuration, a uniform plasma forming region can be formed in a wide range in the vacuum vessel by controlling the magnetic fields of the plurality of coil portions by the control means.
[0012]
In this case, the plasma region expanding means is preferably provided with a drive means for changing the angle of the steering coil with respect to the plasma emission central axis direction.
[0013]
By adopting such a configuration, it is possible to widen the emission angle of the plasma emitted from the plasma gun and form a uniform plasma formation region in a wide range in the vacuum vessel.
[0014]
Further, in this case, if the workpiece is conveyed in a direction parallel to the plasma emission central axis direction, in other words, in a direction orthogonal to the direction of changing the incident direction, It is preferable that a uniform film can be obtained in the direction perpendicular to the direction in which the incident direction is changed (transport direction).
[0015]
Further, the plasma processing method according to the present invention varies the plasma emission central axis direction of the plasma emitted from the plasma source, expands the plasma region generated by the plasma source, and enters the vacuum vessel in a plasma atmosphere. A film forming material is formed on the disposed object to be processed.
[0016]
Further, in this case, the plasma is bent from the plasma emission central axis direction and enters the electrode part, and the incident direction is the electrode part and the workpiece to be disposed facing the electrode part. It is characterized by being changed to the extending direction of a plane orthogonal to the connecting straight line.
[0017]
With the above configuration of the present invention, a wide and uniform plasma formation region can be formed. Thereby, a film of uniform quality can be obtained in a wider film formation area than in the past.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Next, a plasma processing apparatus and a processing method thereof according to the present invention will be described with reference to the drawings. First, a schematic configuration of the ion plating apparatus according to the present embodiment will be described with reference to FIG. In addition, E shown in FIG. 1 has shown the plasma emission center-axis direction of the plasma discharge | released from a plasma source.
[0019]
In general, the ion plating apparatus 10 includes a vacuum vessel 12 that is a film forming chamber, a plasma gun (plasma beam generator) 14 that is a plasma source that supplies a plasma beam (plasma) PB into the vacuum vessel 12, and a vacuum vessel. 12 is provided with an anode member (electrode part) 16 that is disposed at the bottom of 12 and receives a plasma beam PB, and a transport mechanism 18. The transport mechanism 18 is for appropriately moving a substrate holding member WH that holds a substrate (film formation target) W that is an object of film formation above the anode member 16. The vacuum vessel 12 is grounded. Reference numerals 20b and 20c indicate supply paths for supplying an atmospheric gas such as oxygen, and reference numeral 20d indicates a supply path for supplying an inert gas such as Ar to the hearth 16a described later. Reference numeral 20e indicates an exhaust system.
[0020]
The plasma gun 14 is of a pressure gradient type, and its main body is provided on the side wall of the vacuum vessel 12. The generated and emitted plasma beam PB is converged by controlling the intensity and distribution state by the cathode 14a, the intermediate electrodes 14b and 14c and the electromagnet coil 14d of the plasma gun 14. The converged plasma beam PB is further introduced into the vacuum vessel 12 with the plasma emission direction controlled by the steering coil 15. Details of the steering coil 15 will be described later. Reference numeral 20a indicates a carrier gas introduction path made of an inert gas such as Ar, which is the source of the plasma beam PB.
[0021]
The anode member 16 includes a hearth 16a as a main anode for guiding the plasma beam PB downward, and an annular auxiliary anode 16b disposed around the hearth 16a. The hearth 16a which is an electrode portion according to claim 1 has a positive potential and sucks the plasma beam PB emitted from the plasma gun 14 downward in FIG. In the hearth 16a, a through hole TH is formed at a central portion where the plasma beam PB is incident, and the film forming material 22 is loaded into the through hole TH. The film forming material 22 is a tablet formed into a columnar shape or a rod shape, and is heated by an electric current from the plasma beam PB to generate an evaporated substance. The hearth 16a has a structure for gradually raising the film forming material 22, and the upper end of the film forming material 22 always protrudes from the through hole TH of the hearth 16a by a certain amount.
[0022]
The auxiliary anode 16b is composed of an annular container disposed concentrically around the hearth 16a, and a permanent magnet 24a and a coil 24b are accommodated in the container. The permanent magnet 24a and the coil 24b are magnetic field control members, and thereby the direction of the plasma beam PB incident on the hearth 16a is controlled. The transport mechanism 18 has a large number of rollers 18b arranged in the transport path 18a at equal intervals in the horizontal direction to support the substrate holding member WH, and rotates the rollers 18b to move the substrate holding member WH horizontally at a predetermined speed. And a driving device to be moved. The substrate W, which is an object to be processed, is held on the substrate holding member WH. At this time, the substrate W may be fixed above the inside of the vacuum vessel 12 with a vacuum chuck without providing the transport mechanism 18 for transporting the substrate W.
[0023]
Here, the details of the steering coil 15 and the means for expanding the plasma formation region by changing the plasma emission direction of the plasma controlled by the steering coil 15, that is, the plasma region expansion means according to claim 1 will be described. To do. As a means for changing the plasma emission direction of the plasma, an appropriate method such as a mechanical method or an electric method can be used. The case where the plasma emission direction of plasma is changed using a mechanical method will be described with reference to FIGS. The mechanical plasma region expansion means is provided with a drive mechanism 26 which is a drive means described later.
[0024]
2 is a plan view of the steering coil 15a corresponding to the steering coil 15 of FIG. 1 (viewed from the direction S1 in FIG. 1), and FIG. 3 is a front view of the steering coil 15a (direction S2 in FIG. 1). FIG. 4 is a side view of the steering coil 15a (a view seen from a direction penetrating the paper surface in FIG. 1). 2 and 3, the illustration of the plasma gun 14 is omitted. Further, E shown in FIGS. 2 to 4 indicates the plasma emission central axis direction of the plasma emitted from the plasma source.
[0025]
In a normal apparatus, an electromagnetic coil or a permanent magnet is annularly fixed to the outer periphery of the plasma beam PB as a control member corresponding to the steering coil 15a. Then, the plasma beam PB controlled by the control member is introduced into the vacuum vessel 12 and irradiated onto the extended line in the plasma emission central axis direction E. As described above, the plasma beam PB irradiated into the vacuum vessel 12 is bent in the direction of the hearth 16a by the action of the anode member 16, and is converged toward the hearth 16a.
[0026]
At this time, as shown in FIG. 2, the hearth 16a as viewed from above, in other words, a plane orthogonal to a straight line (in this case, a vertical line) connecting the anode member 16 and the substrate W (in FIG. 1) When viewed from the plane of the paper surface, for example, the plasma beam PB incident on the hearth 16a whose horizontal distance L from the center of the control member is 500 mm is the center of the hearth 16a (FIGS. 1 and 2). The light is radiated and diffused from the center to the hearth 16a after being radiated and diffused from a constant width (indicated by an arrow C) in FIG. The width of the plasma beam PB spreading on a plane (in this case, the horizontal plane) is, for example, about W1 = 400 mm to W2 = 600 mm. Within the width of W1 = 400 mm from the center C of the hearth 16a, the plasma beam PB is uniform, that is, has a substantially constant plasma density. On the other hand, the plasma beam PB having a width of about 100 mm at each end is not suitable. The region is uniform, the plasma density is low, or the plasma density is easily changed.
[0027]
For this reason, the film-forming material particles evaporated from the film-forming material 22 arranged in the hearth 16a are activated to a good state by the plasma beam PB and ionized when rising in the vicinity immediately above the hearth 16a. Fly towards On the other hand, when ascending around the hearth 16a, activation is not sufficiently performed depending on the peripheral portion of the plasma beam PB, and the ionized state and the flying state toward the substrate W become unstable. Therefore, the practical film formation range on the substrate W is limited to a width corresponding to the width of W1 = 400 mm.
[0028]
In the present embodiment, an electromagnetic coil wound around a circular core similar to a normal one in a fixed direction is used as a steering coil 15a, and a vertical support shaft 24 of the steering coil 15a is used as a cylinder 26a of a drive mechanism 26 as a crank mechanism. 28 has a structure engaged by. Then, by rotating the vertical support shaft 24 in the horizontal direction (X1-X2 direction in FIG. 2) by the reciprocation of the cylinder 26a, the direction of the steering coil 15a with respect to the plasma emission central axis direction E is set at a predetermined cycle. It has a structure that is displaced in the width direction (left-right direction in FIG. 2). The swing angle θ1 of the steering coil 15a on the horizontal plane is not particularly limited, and is an appropriate angle depending on the film formation method, the structure of the apparatus, the size of the apparatus, the degree of required film formation quality, and the like. Can be set to
[0029]
Further, the number of repetitions per unit order (unit: times / min, the reciprocal of the cycle) for changing the steering coil 15a to the swing angle θ1 is not particularly limited as in the case of the predetermined angle. For example, the swing angle θ1 can be about ± 10 ° across the direction toward the center C of the hearth 16a, and the number of repetitions per unit order can be, for example, 30 times / min. As a result, the width of the plasma density of the plasma beam PB can be expanded from W1 = 400 mm to about 50 mm on both sides of W1, and the practical film formation range of the substrate W can be increased accordingly. Can be expanded in the width direction orthogonal to the transport direction.
[0030]
At this time, in this embodiment, since the film is formed while transporting the substrate W in the direction orthogonal to the width direction, the film formation quality in this direction can be made uniform. In addition, when using the mechanical method, an annular permanent magnet may be used instead of the steering coil.
[0031]
Next, with reference to FIG. 5 and FIG. 6, a case where the plasma emission direction is changed using an electrical method will be described. The steering coil 15b is provided with two coil portions 32a and 32b which are annular windings surrounding the outer periphery of the plasma. The coil portions 32a and 32b have a configuration in which the winding direction is changed by 30 °, for example. The control means 30 is provided in the plasma region expansion means using the electric system, and the plasma beam PB passes by energizing the two coil portions 32a and 32b alternately by the control means 30. The direction of the magnetic field generated in the space (S in FIGS. 5 and 6) can be changed, and as a result, the plasma emission direction of the plasma beam PB can be changed. Thereby, the same effect as the case where the said mechanical system is used can be acquired.
[0032]
At this time, the swing angle of the steering coil 15b with respect to the plasma emission central axis direction E and the number of repetitions per unit order swinging to the swing angle θ1 are not particularly limited as in the case of using the mechanical method. For example, the swing angle is ± 10 ° and the number of repetitions is about 10 to 50 times / sec. The electrical method and the mechanical method may be used in combination. At this time, for example, by forming the swing angle to ± 20 ° and the number of repetitions to about 10 to 50 times / sec, plasma formation is performed. The area can be further expanded.
[0033]
An ion plating method according to the present embodiment using the ion plating apparatus configured as described above will be described. First, the film-forming material 22 is attached to the through hole TH of the hearth 16 a arranged at the lower part of the vacuum container (film-forming chamber) 12. On the other hand, a glass substrate W, for example, is disposed at an opposing position above the hearth 16a. Then, a negative voltage is applied to the cathode 14a of the plasma gun 14 and a positive voltage is applied to the hearth 16a across the vacuum vessel 12 at the ground potential, thereby generating a discharge, thereby generating a plasma beam PB.
[0034]
The voltage of the hearth 16a in a state where the discharge is stable is set within a range of, for example, +30 to +60 V with respect to the vacuum vessel 12 (wall of the vacuum vessel 12). The voltage of the hearth 16a can be adjusted by changing conditions such as the magnetic field, the pressure of the vacuum vessel 12, and the discharge current. The plasma beam PB is guided by a magnetic field determined by the steering coil 15 (15a, 15b), the permanent magnet 24a in the auxiliary anode 16b, etc., and reaches the hearth 16a. At this time, since argon gas is supplied around the film forming material 22, the plasma beam PB is easily attracted to the hearth 16a.
[0035]
At this time, by using the mechanical or electrical method described above, the direction of the steering coil 15 (15a, 15b) with respect to the plasma emission central axis direction E is changed, and the incident direction of the plasma beam PB is changed. The region (plasma atmosphere range) of the plasma beam PB above 16a is expanded. The film forming material 22 exposed to the plasma beam PB is gradually heated. When the film forming material 22 is sufficiently heated, the film forming material 22 is sublimated, and the evaporated substance is evaporated (emitted). The evaporated material is ionized in the high-density plasma beam PB just above the hearth 16a.
[0036]
Since the potential immediately above the hearth 16a in the plasma beam PB is substantially the same as the potential of the hearth 16a, the positively ionized evaporation substance (element of the vapor deposition material) has a potential substantially equal to the potential of the hearth 16a, that is, Has potential energy. Further, in the present embodiment, since the width of the plasma beam PB is spread around the hearth 16a, the region where the evaporated substance has a potential substantially equal to the potential of the hearth 16a, that is, the potential energy is also centered on the hearth 16a. Extend as.
[0037]
Thereby, an evaporating substance having a uniform potential energy is deposited over a wide range on the substrate W, and a uniform thin film is formed. In the ion plating method according to the present embodiment, instead of changing the direction of the steering coil 15 (15a, 15b), the anode member 16 is rotated by the same method as that for the steering coil 15 (15a, 15b). The steering coil may be displaced with respect to the plasma emission central axis direction E of the plasma beam PB by moving or swinging.
[0038]
【Example】
The present invention will be further described with reference to examples and comparative examples. In addition, this invention is not limited to the Example demonstrated below. ITO was deposited to a thickness of about 170 nm under the deposition conditions of a discharge current of 100 A, a vacuum vessel pressure of 0.3 Pa, and a glass substrate holding temperature of 80 to 120 ° C. At this time, the swing angle (θ1) of the steering coil with respect to the plasma emission central axis direction E is set to ± 3 °, and the number of rotations (times / min) that is the reciprocal of the period is changed to a maximum of 10 to Changed.
[0039]
As the film quality of the obtained ITO film, the distribution in the width direction of the specific resistance (unit: × 10 ⁻⁴ Ω · cm) is shown in FIG. 7, and the ITO film with the sheet resistance (unit: Ω / □) is shown in FIG. The distribution in the width direction is shown in FIG. The width of the ITO film corresponds to the width direction (W1, W2) of the plasma beam after aligning the width center of the film and the width center of the plasma beam, in other words, the hearth center on the vertical line. is there.
[0040]
7 and 8, the number of rotations 0 means a conventional case (comparative example) in which the steering coil is fixed. In this comparative example, when the width of the ITO film is within a range of 200 mm on both sides from the center, both the specific resistance and the sheet resistance are almost uniform. When the width of the ITO film exceeds the range of 200 mm on both sides from the center, both the specific resistance and the sheet resistance increase rapidly.
[0041]
On the other hand, in the embodiment in which the steering coil is shaken, the specific resistance and the sheet resistance are almost uniform values regardless of the number of rotations when the width of the ITO film is in the range of 200 mm on both sides from the center. It has been. In addition, the increase in specific resistance and sheet resistance is suppressed even when the width of the ITO film exceeds the range of about 200 mm on both sides from the center by about 50 mm, that is, within the width of 250 mm on both sides. In this embodiment, in the region where the width of the ITO film exceeds 250 mm on both sides from the center, both the specific resistance and the sheet resistance are considerably increased, and no remarkable improvement effect is observed. However, by optimizing the plasma beam emission direction by further increasing the swing angle θ1 or by further increasing the number of rotations, the range of the width where uniform film formation quality can be obtained can be further expanded. Is clear.
[0042]
The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to such specific embodiments, and various modifications can be made within the scope of the gist of the present invention described in the claims. Deformation / change is possible. In addition, changing the substantial direction of the steering coil according to claim 1 includes both a mechanical system and an electrical system, and the steering coil 15 ( 15a, 15b) is changed.
[0043]
【The invention's effect】
According to the plasma processing apparatus of the present invention, the plasma emitted from the plasma source is periodically changed in the emission direction within a predetermined angle, and is incident on the electrode portion disposed in the vacuum vessel, so that the plasma atmosphere Since the film is deposited on the surface of the workpiece placed in the vacuum vessel, it is possible to form a uniform plasma formation region over a wide range, and to obtain a film of uniform quality over a wider deposition area than before. Can do.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration of an ion plating apparatus according to the present embodiment.
FIG. 2 is a plan view showing a steering coil portion provided with mechanical plasma region expansion means in FIG.
FIG. 3 is a front view showing a steering coil portion provided with mechanical plasma region expansion means in FIG.
FIG. 4 is a side view showing a steering coil portion provided with a mechanical plasma region expanding means in FIG.
FIG. 5 is a plan view showing a steering coil portion provided with an electric plasma region expansion means in FIG.
FIG. 6 is a front view showing a steering coil portion provided with an electric plasma region expansion means in FIG.
FIG. 7 is a diagram showing a specific resistance distribution of ITO formed in the width direction of a substrate corresponding to the width direction of an incident plasma beam.
FIG. 8 is a diagram showing a sheet resistance distribution of ITO formed in the width direction of the substrate corresponding to the width direction of an incident plasma beam.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Ion plating apparatus 12 Vacuum vessel 14 Plasma gun 15, 15a, 15b Steering coil 16 Anode member 16a Heart 16b Auxiliary anode 18 Conveying mechanism 22 Film forming material 24a Permanent magnet 24b Coil 25 Vertical support shaft 26 Drive mechanism 26a Cylinder 28 Crank mechanism 29a, 29b Horizontal support shaft 30 Control means 32a, 32b Coil portion

Claims (7)

A vacuum vessel;
A plasma source for generating plasma connected to the vacuum vessel;
An electrode part disposed in the vacuum container, the film forming material is disposed, and the plasma is incident thereon;
A steering coil for guiding the plasma into the vacuum vessel,
In a plasma processing apparatus for forming the film forming material on an object to be processed that is disposed to face the electrode portion,
Plasma processing comprising plasma region expansion means for expanding a plasma region generated by the plasma source by changing a substantial direction of the steering coil with respect to a plasma emission central axis direction from the plasma source apparatus. The electrode portion is disposed in a direction orthogonal to the plasma emission central axis direction of the plasma gun,
The object to be processed is disposed at a position facing the electrode part,
2. The plasma processing apparatus according to claim 1, wherein the plasma is bent from the plasma emission central axis direction and incident on the electrode portion to form a film on the object to be processed. The plasma region expansion means includes
While constituting the steering coil,
A plurality of coil portions having different angles with respect to the plasma emission central axis direction;
The plasma processing apparatus according to claim 1, further comprising a control unit that controls magnetic fields of the plurality of coil units. The plasma region expansion means includes
The plasma processing apparatus according to claim 1, further comprising a driving unit that changes an angle of the steering coil with respect to the plasma emission central axis direction. The plasma processing apparatus according to claim 1, wherein the object to be processed is configured to be conveyed in a direction parallel to the plasma emission central axis direction. By changing the plasma emission central axis direction of the plasma emitted from the plasma source,
A plasma processing method, wherein a plasma region generated by the plasma source is expanded, and a film forming material is formed on an object to be processed disposed in a vacuum vessel in a plasma atmosphere. The plasma is bent from the plasma emission central axis direction and enters the electrode part, and the incident direction is orthogonal to the electrode part and a straight line connecting the object to be processed and opposed to the electrode part. The plasma processing method according to claim 6, wherein the plasma processing method is changed to an extending direction of a flat surface.

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