JP2012104559A - Device and method for plasma deposition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain uniform plasma even when a substrate to be processed having a large area is processed by supply of VHF-band high-frequency power.SOLUTION: In a plasma deposition device, a second principal plane of a first electrode includes a plurality of first feeding points, a plurality of second feeding points, at least a third feeding point and at least a fourth feeding point. The plurality of first feeding points and the plurality of second feeding points are disposed in symmetric positions relative to a symmetry point, and in symmetric positions relative to a symmetry axis, and the high-frequency power fed thereto mutually has a 180-degree phase difference. The at least one third feeding point and the at least one fourth feeding point include a set of feeding points disposed in either positions having an equal distance from the symmetry point and positions on the symmetry axis, or positions having an equal distance from the symmetry point and in symmetric positions relative to the symmetry axis.

Description

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

  A plasma film forming apparatus is widely used as an apparatus for forming a thin film such as an amorphous silicon thin film or a microcrystalline silicon thin film on a substrate. Nowadays, for example, a plasma film forming apparatus capable of forming a large-area thin film such as a thin film transistor used in a power generation layer of a thin film silicon solar cell or a flat display panel at a high speed at a time has been developed. In order to form a silicon thin film having a large area, it is common to use a parallel plate type plasma film forming apparatus.

The parallel plate type plasma film forming apparatus has two electrodes facing each other with a distance of several mm to several tens mm in the vacuum chamber. These two electrodes are installed in a horizontal plane, supply high-frequency power to one electrode, and the other electrode is grounded. In the case of forming a silicon thin film, a film forming gas such as silane (SiH ₄ ) or hydrogen (H ₂ ) is supplied to a gap region between the electrodes serving as a discharge space through a large number of gas holes provided in one electrode. . The gas supplied to the discharge space is turned into plasma by high frequency power. The deposition gas is decomposed in the plasma, becomes radicals and ions, and enters the deposition target substrate to form a silicon film on the substrate. In general, the other electrode on the grounded side is used as a stage, and a deposition target substrate is placed on the other electrode.

  Patent Document 2 describes that in a plasma processing apparatus that generates plasma between an electrode and a substrate holder, high frequency power of 10 MHz to 30 MHz is supplied to two portions of the electrode. Specifically, the high-frequency power supplied to the two left and right parts of the electrode is generated so as to be two types of pulse-modulated outputs that are time-divided so as not to interfere with each other. Thus, according to Patent Document 2, the electric field strength distribution when high-frequency power is supplied to only one of the two parts and the electric field strength distribution when high-frequency power is supplied to only the other are superimposed and time-averaged. It is said that since the electric field strength distribution can be obtained, the plasma uniformity over the entire surface of the large-area substrate (the length and width of 1 m × 1 m or more) can be improved.

  On the other hand, in recent years, VHF plasma generated using high frequency power in the VHF (Very High Frequency) band having a frequency higher than that of the conventional 13.56 MHz is used to meet the needs for improving film formation quality and film formation speed. It has been actively studied for use in film formation. Since VHF plasma has the characteristics of high density and low electron temperature, it is expected as a solution to the above needs.

  However, when the frequency of the high-frequency power increases, the property of the high-frequency power as a “wave” appears remarkably, and the film forming characteristics tend to be non-uniform in the electrode plane. That is, when the frequency of the high-frequency power increases, the high-frequency power causes interference in the electrode plane, and the electric field strength distribution becomes non-uniform by forming a standing wave, resulting in non-uniform plasma density. The film forming speed and film quality itself tend to be non-uniform. In recent years, an increase in the size of a film formation substrate has become a factor that makes this tendency remarkable, and has become a major issue in practical use.

  In general, the electrode size is desirably 1/10 or less of the wavelength λ of the high-frequency power used. This is because, as a guide, if the electrode size is λ / 10 or less, the in-plane variation of the electric field strength is generally within ± 10% even when a standing wave is formed. For example, when the frequency of the high frequency power is 13.56 MHz, the electrode size is limited to a little over 2 m, and when the frequency of the high frequency power is in the VHF band, for example, 60 MHz, the electrode size is limited to about 50 cm.

  Here, film formation characteristics, for example, variations in film thickness distribution are within a range of about ± 5% in order to ensure reproducibility in flat panel display thin film transistors and the like, and in order to ensure reproducibility in the field of solar cells. The fact that it is within the range of about ± 10% is one indicator of practical use. In the conventional VHF plasma technology, for example, in the case of an amorphous silicon film deposition rate, a substrate area of about 50 cm × 50 cm is about ± 10 to 15%, which is barely satisfied with a small area substrate.

  In Patent Document 1, in a surface treatment apparatus that generates plasma between an electrode body and a substrate holder, high-frequency power in the VHF band of about 60 to 150 MHz is branched into four by a branching device, and the four powers in the electrode body. The supply to the supply point is described. In addition, it is described that four power supply locations are set symmetrically with respect to the center of the back surface of the electrode body so that the power supply paths to the front surface of the electrode body are equal. Thereby, according to Patent Document 1, since the four power supply locations are set at equal positions, the distribution of the high-frequency power supplied to the entire surface of the electrode body becomes uniform, and uniform plasma is generated. Has been.

Japanese Patent No. 3425209 JP 2006-216679 A

  On the other hand, the above-mentioned index tends to be unclearable at about ± 20 to 40% on a recent meter-sized substrate (1.1 m × 1.4 m).

  In the surface treatment apparatus described in Patent Document 1, if the four power supply locations are set at equal positions, the standing wave is supplied by simultaneously supplying high-frequency power from the four power supply locations in the electrode body to the electrode body. It is said that the occurrence of

  However, Patent Document 1 describes that the substrate to be processed is a glass substrate having a size of about 550 mm × 650 mm. In the technique described in Patent Document 1, it is considered that a meter-sized substrate is not assumed to be processed. If the technique described in Patent Document 1 is applied to a meter-sized substrate, a standing wave composed of high-frequency power supplied from each power supply location is formed, resulting in non-uniformity in plasma distribution. Conceivable.

  When the present inventor actually examined, an attempt was made to generate plasma by simultaneously supplying power from four points around the electrode to a 1.1 m × 1.4 m large substrate, but the plasma was localized in the center of the electrode. A uniform plasma was not obtained. Since the formation of standing waves is caused by the fundamental physical phenomenon of wave interference, it is considered that the fundamental solution (suppressing the standing waves themselves) is very difficult.

  As described above, when a meter-sized substrate (substrate to be processed having a large area) is processed using the surface treatment apparatus described in Patent Document 1, it is difficult to obtain uniform plasma.

  Patent Document 2 describes supplying high frequency power of 10 MHz to 30 MHz as described above. In the technique described in Patent Document 2, it is considered that high-frequency power in the VHF band is not supposed to be supplied.

  That is, in the technique described in Patent Document 2, the power sources connected to the positions facing each other on the electrode surface are alternately turned on / off so that they do not interfere with each other. However, when the frequency is in the VHF band, the formation of standing waves becomes more prominent, and as a result, the electric field distribution has a curved shape with nodes. Even in this VHF band, it is possible to make uniform by superimposing two standing waves, but the condition that the positions of the antinode and the node are exactly π / 4 (for example, the electrode size is an odd multiple of λ / 4). Limited to satisfy. Moreover, in an actual film formation or etching process, the plasma parameter changes depending on the process conditions, and λ also changes accordingly. Accordingly, the process margin tends to be very small from a practical viewpoint, and it is difficult to apply the technique described in Patent Document 2 to the frequency region of the VHF band.

  In addition, in the method described in Patent Document 2 in which power supply is performed by alternately turning on / off a plurality of parts, a matcher (matching) in which an on-state power supply condition is connected to an off-state power supply part. The matching of the matcher tends to be difficult. From this point of view, it is difficult to apply the technique described in Patent Document 2 to the frequency region of the VHF band.

  As described above, when the high-frequency power in the VHF band is supplied using the plasma processing apparatus described in Patent Document 2, it is difficult to obtain uniform plasma.

  The present invention has been made in view of the above, and a plasma film forming apparatus and a plasma capable of obtaining uniform plasma even when a substrate to be processed having a large area is processed by supplying high-frequency power in the VHF band. It aims at obtaining the film-forming method.

  In order to solve the above-described problems and achieve the object, a plasma film forming apparatus according to one aspect of the present invention includes a vacuum chamber and a first electrode, and a film forming chamber is formed in the film forming chamber. A deposition target substrate is placed on a second electrode disposed to face the first electrode, and deposition is performed using plasma generated between the first electrode and the second electrode. The first electrode has a square shape, and the second electrode of the first electrode opposite to the first main surface facing the second electrode is a plasma film forming apparatus for performing The main surface has a plurality of first feeding points arranged on one side of the two opposite sides in the square, and a plurality of second feeding points arranged on the other side of the two opposite sides, At least one third feeding point arranged on one side of the other two opposite sides of the square, and the opposite other At least one fourth feeding point disposed on the other side of the two sides, wherein the plurality of first feeding points and the plurality of second feeding points are symmetrical with respect to a symmetry point. The phase difference between the fed high frequency powers is 180 degrees, and the at least one third feeding point and the at least one fourth feeding point are Each including a set of feeding points that are equidistant from the symmetry point and are located on the symmetry axis, or are equidistant from the symmetry point and are symmetric with respect to the symmetry axis. It is characterized by that.

  According to the present invention, the high-frequency power source connected to the third feeding point and the fourth feeding point on the axis of symmetry (equivalently) includes the plurality of first feeding points on the two opposite sides and the plurality of feeding points. It is hard to be influenced by the high frequency power source connected to the second feeding point. In addition, the high-frequency power source connected to the plurality of first feeding points and the plurality of second feeding points on the two opposite sides is (equivalently) the third feeding point and the fourth feeding point on the axis of symmetry. It is easy to achieve matching without being affected by the matching state of the high-frequency power source connected to the feeding point. As a result, the V-shaped electric field intensity distribution by the plurality of first feeding points and the plurality of second feeding points and the ridge-type electric field intensity distribution by the third feeding point and the fourth feeding point are independently obtained. Since they can be formed and stably stacked, uniform plasma can be obtained even when a substrate to be processed having a large area is processed by supplying high-frequency power in the VHF band.

FIG. 1 is a cross-sectional view illustrating the plasma processing apparatus according to the first embodiment. FIG. 2 is a high-frequency power feeding system diagram according to the first embodiment. FIG. 3 is an electric field distribution diagram measured on the atmosphere side of the first electrode. FIG. 4 is an electric field distribution diagram formed between the first electrode and the stage. FIG. 5 is an electric field distribution diagram formed between the first electrode and the stage. FIG. 6 is an electric field distribution diagram formed between the first electrode and the stage. FIG. 7 is an operation diagram of the high-frequency power supply according to the third embodiment. FIG. 8 is a high-frequency power feeding system diagram according to the fourth embodiment. FIG. 9 is a high-frequency power feeding system diagram according to the fifth embodiment.

  Embodiments of a plasma film forming apparatus according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to these embodiments.

Embodiment 1 FIG.
The structure of the plasma film-forming apparatus 100 concerning Embodiment 1 is demonstrated using FIG. FIG. 1 is a cross-sectional view schematically illustrating a configuration of a plasma film forming apparatus 100 according to the first embodiment.

  As shown in FIG. 1, a plasma film forming apparatus 100 includes a vacuum chamber 1, an exhaust port 3, a film forming chamber 8, an insulating flange 4, an electrode (first electrode) 5, a gas supply port 6, a shower plate 7, a stage. (Second electrode) 2 and a plurality of high-frequency power supplies 10a to 10f.

  The vacuum chamber 1 forms side portions and bottom portions on the outer wall of the plasma film forming apparatus 100, and extends so as to cover the side portions and bottom portion of the film forming chamber 8.

  The exhaust port 3 communicates with the vacuum chamber 1 and is connected to a vacuum pump (not shown) via an exhaust pipe (not shown), and is provided for exhausting the vacuum chamber 1 with the vacuum pump. It has been.

  The film forming chamber 8 is a space formed by being covered with the electrode 5 and the vacuum chamber 1. In the film forming chamber 8, plasma is generated as described later.

  The insulating flange 4 insulates the electrode 5 from the vacuum chamber 1 in terms of high-frequency power and vacuum-seals the electrode 5 from the vacuum chamber 1. Thereby, the film forming chamber 8 is a space that can be evacuated.

  The electrode 5 forms an upper part of the outer wall of the plasma film forming apparatus 100 and extends to cover the upper part of the film forming chamber 8. Further, the electrode 5 extends so as to cover, for example, the upper part and the side part of the film forming chamber 8. A plurality of high frequency power supplies 10 a to 10 f are connected to the electrode 5.

  The gas supply port 6 is connected to a gas supply source (not shown) via a gas supply pipe (not shown), and a film is formed from the gas supply source in a space 11 between the electrode 5 and the shower plate 7. It is provided to supply gas.

  The shower plate 7 extends to cover the lower part of the space 11 and has a plurality of gas holes. Thus, the shower plate 7 introduces the film forming gas from the space 11 into the film forming chamber 8 through the plurality of gas holes.

  The stage 2 is disposed so as to face the first main surface 5 a of the electrode 5 in the film forming chamber 8 and is grounded, for example, and functions as a counter electrode (second electrode) with respect to the electrode 5. In addition, a deposition target substrate 9 is placed on the stage 2.

  The plurality of high frequency power supplies 10 a to 10 f are connected to positions to be described later on the second main surface 5 b of the electrode 5, and supply high frequency power to the electrode 5. The second main surface 5b is a surface on the opposite side of the first main surface 5a facing the stage 2 in the electrode 5.

  In the plasma film forming apparatus 100, the film forming gas supplied from the gas supply port 6 is introduced into the film forming chamber 8 through the plurality of gas holes of the shower plate 7, and the pressure in the film forming chamber 8 is reduced to a vacuum pump (see FIG. (Not shown). In this state, when a high frequency is applied to the electrode 5 from the plurality of high frequency power supplies 10 a and 10 b, plasma is generated between the electrode 5 and the stage 2, and a thin film is deposited on the deposition target substrate 9.

  Next, a method of supplying high-frequency power to the electrode 5 applied to the plasma film forming apparatus 100 will be described with reference to FIG. FIG. 2 is a diagram showing a system / configuration of a plurality of high-frequency power supplies 10a to 10f for supplying high-frequency power to the electrode 5 in the plasma film forming apparatus.

  In FIG. 2, as an example, the electrode 5 is rectangular, the size of the shower plate 7 facing the stage 2 is 1.2 m × 1.5 m, and high-frequency power is supplied from the atmosphere side opposite to the film forming chamber 8 side. The configuration is shown when doing so. For example, a 60 MHz VHF band is used as the frequency of power to be fed in order to realize high-speed film formation.

  First, both short sides 5b1 and 5b2 are considered as the two opposite sides of the second main surface 5b of the electrode 5, and both long sides 5b3 and 5b4 are considered as the other two opposite sides of the second main surface 5b. A method of supplying high frequency power in the VHF band to the electrode 5 from both short sides 5b1 and 5b2 will be described.

  High-frequency power feed points 27 a and 27 b are provided on the short side 5 b 1 side of the electrode 5, and high-frequency power feed points 27 c and 27 d are provided on the short side 5 b 2 side of the electrode 5. In other words, the electrode 5 has a rectangular shape, and the second main surface 5b has a plurality of feeding points (a plurality of feeding points) arranged on one side (short side 5b1) of the two opposite sides in the square. First feeding points) 27a and 27b, and a plurality of feeding points (a plurality of second feeding points) 27c and 27d arranged on the other side (short side 5b2) of the two opposite sides. The plurality of feeding points (a plurality of first feeding points) 27 a and 27 b and the plurality of feeding points (a plurality of second feeding points) 27 c and 27 d are arranged in line-symmetric positions with respect to the symmetry axis 28. Further, the feeding point 27a and the feeding point 27d are arranged at point-symmetrical positions with respect to the symmetry point C. The feeding point 27b and the feeding point 27c are arranged at point-symmetrical positions with respect to the symmetry point C.

  Matchers 26a, 26b, 26c, and 26d that adjust the matching state of the high-frequency power are connected to the feeding points 27a, 27b, 27c, and 27d, respectively. For connection from the matchers 26a to 26d to the feeding points 27a to 27d, a metal plate or rod having good conductivity (not shown) or a high-frequency coaxial cable is used. These four feeding points 27a to 27d form a rectangle, and each is set in a region near the electrode periphery.

  The matchers 26a, 26b, 26c and 26d are fed with the high frequency power amplified by the high frequency amplifiers 25a, 25b, 25c and 25d, respectively.

  The signal generator 21 generates a VHF power signal (for example, a 60 MHz sine wave) and supplies it to the distributor 22. The distributor 22 distributes a VHF power signal (for example, a 60 MHz sine wave) into, for example, six power signals and supplies the power signal to the phase shifter 23.

  The phase shifter 23 adjusts the phase of each of the six power signals. That is, the phase shifter 23 includes six phase adjustment units 23a to 23f corresponding to the six power signals. The six phase adjusters 23a to 23f receive the six power signals and adjust the phase. Each of the phase adjusters 23a to 23f supplies the adjusted power signal to the corresponding on / off switch 24a to 24f.

  The on / off switchers 24a, 24b, 24c, 24d, 24e, and 24f pulse the output signal (power signal) from the phase shifter 23, and the high frequency is supplied to the corresponding high-frequency amplifiers 25a, 25b, 25c, 25d, 25e, and 25f. Input as power.

  The phase control (phase adjustment) in the phase shifter 23 may be controlled by a controller (not shown). Alternatively, in order to turn on / off the high frequency output to the on / off switchers 24a to 24f, an on / off signal may be input and controlled from a controller (not shown). Alternatively, in some cases, the on / off switchers 24a to 24f can be used as a continuous output without performing an on / off operation.

  In the above configuration, the signal generator 21 generates a VHF power signal (for example, a 60 MHz sine wave), and the phase shifter 23 sets the phase of the high-frequency power (power signal) to be supplied to the feeding points 27a and 27b to the same phase. And the phase of the high-frequency power (power signal) to be supplied to the feeding points 27c and 27d is set to 180 degrees opposite to the phase of the high-frequency power at the feeding points 27a and 27b. In this state, high frequency power in the VHF band is supplied from the high frequency amplifiers 25a, 25b, 25c, and 25d.

  That is, each of the high frequency power supplies 10a to 10d is equivalent to the signal generator 21, the distributor 22, the phase shifter 23, the corresponding on / off switchers 24a to 24d, the corresponding high frequency amplifiers 25a to 25d, and the corresponding matcher. It functions as a power supply circuit having 26a to 26d. The plurality of high-frequency power supplies 10a to 10d supply high-frequency power in the VHF band to the plurality of power supply points 27a to 27d.

  The inventor measured the electric field distribution on the electrode surface (second main surface 5b) on the atmosphere side (second main surface 5b side) of the electrode 5 with the high voltage probe in the above state. The result is shown in FIG. The graph displays the electric field strength on the electrode surface (second main surface 5b) in three dimensions, and the electric field strength is normalized by the maximum value of the high frequency amplitude.

  From the graph shown in FIG. 3, the electric field strength is strong on both short sides 5b1 and 5b2, and a V-shape with a trough on the symmetry axis 31 formed by a feeding point that feeds high-frequency power in the VHF band from the short sides 5b1 and 5b2. It became a type distribution. The high-frequency electric field distribution on the electrodes forms a rectangle with the four feeding points 27a to 27d even when the feeding points 27a, 27b, 27c and 27d are moved closer to the center or closer to the long sides 5b3 and 5b4. In this way, a similar V-shaped pattern of peaks and valleys was formed. That is, if a rectangular shape is formed by the four feeding points 27a to 27d, a plurality of feeding points (a plurality of first feeding points) 27a, 27b and a plurality of feeding points (a plurality of second feeding points) 27c, 27d It was confirmed that a trough (a node of the high frequency electric field) where the high frequency electric field becomes the minimum value is formed on the symmetry axis 31 of FIG.

  Here, the reason why the valley (node of the high-frequency electric field) where the high-frequency electric field is minimum is formed on the symmetry axis 31 between the feeding points 27a and 27b and the feeding points 27c and 27d is considered as follows. . Since the feeding point 27c and the feeding point 27d are fed in opposite phases (180 degrees) with respect to the feeding point 27a and the feeding point 27b, the high-frequency electric field cancels out on the symmetry axis 31, so the high-frequency electric field is minimum (for example, almost zero). )

  Next, in order to know the high-frequency electric field distribution formed between the electrode 5 and the stage 2 that contribute to actual plasma generation, the high-frequency electric field distribution was estimated by electromagnetic field simulation. In the simulation, the insulating flange 4 is made of alumina ceramic, the distance between the electrode (first electrode) 5 and the stage (second electrode) 2 is 10 mm, the plasma generated between the electrodes is uniform, and εr = 60 MHz The medium was 0.95 and tan δ = 3.57.

  FIG. 4 shows a three-dimensional distribution of the electric field obtained from the analysis of the electromagnetic field simulation. In the graph shown in FIG. 4, X indicates the long side direction (direction along the long sides 5b3, 5b4) of the electrode 5, and Y indicates the short side direction (direction along the short sides 5b1, 5b2). Standardized by value. As shown in FIG. 4, the electric field strength was strong on both short sides 5b1 and 5b2, and a V-shaped distribution with a central portion (on the axis of symmetry) as a valley was shown.

  Next, a method of supplying high-frequency power in the VHF band from the both long sides 5b3 and 5b4 of the electrode 5 will be described with reference to FIG.

  A high-frequency power feeding point 27e is provided on the long side 5b3 side (on the second main surface 5b) of the electrode 5, and a high-frequency power feeding point 27f is provided on the long side 5b4 side of the electrode 5. . In other words, the electrode 5 has a rectangular shape, and the second main surface 5b has one of the other two opposite sides (long side) in the square in addition to the four feeding points 27a to 27d. One feeding point (third feeding point) 27e arranged on the side of 5b3) and one feeding point (fourth feeding point) arranged on the other (long side 5b4) side of the other two opposite sides Point) 27f. The feeding point 27e and the feeding point 27f are arranged on the symmetry axis 28. The feeding point 27e and the feeding point 27f are arranged at equidistant positions from the symmetry point C of the feeding points 27a to 27d.

  Matchers 26e and 26f for adjusting the matching state of the high frequency power are connected to the feeding points 27e and 27f, respectively. The positions of the feeding points 27e and 27f are set on the symmetry axis 28 corresponding to the above-described symmetry axis 31 (see FIG. 3) and equidistant from the symmetry center C of the four feeding points 27a to 27d. Similarly to the power supply from the short sides 5b1, 5b2 described above, in order to know the high-frequency electric field distribution formed between the electrode 5 and the stage 2 when power is supplied from the long sides 5b3, 5b4, The electric field distribution was estimated. The simulation conditions were the same as in FIG. 3, and the phase of the high-frequency power at the feeding point 27e and the high-frequency power at the feeding point 27f was set in phase.

  FIG. 5 shows a three-dimensional distribution of the electric field obtained from the analysis of the electromagnetic field simulation. In the graph shown in FIG. 5, X indicates the long side direction of the electrode (the direction along the long sides 5b3 and 5b4), Y indicates the short side direction (the direction along the short sides 5b1 and 5b2), and the electric field strength is the maximum value. It is standardized by. As shown in FIG. 5, the electric field strength showed a ridge-like distribution that was weak on both short sides 5b1 and 5b2 and strong in the center (on the axis of symmetry).

  That is, each high-frequency power source 10e, 10f is equivalent to a signal generator 21, a distributor 22, a phase shifter 23, a corresponding on / off switch 24e, 24f, a corresponding high-frequency amplifier 25e, 25f, and a corresponding matcher. It functions as a power supply circuit having 26e and 26f. The plurality of high frequency power supplies 10e and 10f supply high frequency power in the VHF band to the plurality of power supply points 27e and 27f.

  A method for forming a uniform electric field distribution between the electrode 5 and the stage 2 using the two high-frequency power feeding methods described above will be described below.

  In order to make the electric field uniform, the electric field distributions of the electromagnetic field simulation results obtained by the above two power feeding methods are combined and combined. In the analysis of the electromagnetic field simulation, the phase of the high frequency power at the feeding points 27a and 27b is set to the same phase, and the phase of the high frequency power at the feeding points 27c and 27d is 180 degrees with respect to the phase of the high frequency power at the feeding points 27a and 27b. Set to reverse phase. Next, high-frequency power feeding points 27e and 27f connected on the axis of symmetry 28 of the electrode 5 are fed with high-frequency power in the same phase as the feeding points 27a and 27b. The magnitude of the high-frequency power is the same for the power supplied to each of the four points (27a, 27b, 27c, 27d) on the short sides 5b1, 5b2, and the two points (27e, 27f) on the long sides 5b3, 5b4 side. The electric power supplied to each of them was twice as much as those. That is, the sum of the high frequency powers fed to the four feeding points 27a to 27d on the short side 5b1, 5b2 side and the sum of the high frequency powers fed to the two feeding points 27e, 27f on the long side 5b3, 5b4 side are equal. It was.

  As a result, the electric field distribution shown in FIG. 6 is obtained. The V-shaped distribution obtained by feeding from the short sides 5b1, 5b2 side and the ridge-like distribution obtained by feeding from the long sides 5b3, 5b4 side are obtained. The synthesized pattern has a substantially flat distribution. That is, in the electric field distribution shown in FIG. 6, the electric field uniformity within the electrode surface was ± 10.8% with respect to the average value.

  When plasma is actually generated, it is considered that a plasma distribution corresponding to the electric field distribution obtained by the electromagnetic field simulation is formed and uniform film formation is possible.

Next, the above power feeding method is applied to the plasma film forming apparatus 100 to generate high-frequency plasma with a mixed gas of silane gas (SiH ₄ ) and hydrogen gas (H ₂ ) by using high-frequency power in the VHF band, so that a large area is obtained. An experimental example in which a microcrystalline silicon film is deposited on a glass substrate will be described.

In FIG. 1, a 1400 mm × 1100 mm glass substrate (thickness: 4 mm) was placed on the stage 2 as the deposition target substrate 9. The deposition target substrate 9 was heated to 200 ° C. using a sheath heater (not shown) built in the stage 2. Next, the height position of the stage 2 was adjusted so that the distance between the shower plate 7 and the deposition target substrate 9 was 10 mm. In this state, silane gas (SiH ₄ ) and hydrogen gas (H ₂ ) were supplied to the gas supply port 6 at flow rates of 1 slm and 50 slm, respectively, and the gas pressure in the film forming chamber 8 was adjusted to 1000 Pa. After the gas pressure is stabilized, high frequency power in the VHF band is supplied to the electrode 5 from the high frequency power supply system (high frequency power supplies 10a to 10f) shown in FIG. 2, and a silane (SiH ₄ ) / hydrogen (H ₂ ) mixed plasma is supplied. Was generated. The outputs of the high-frequency amplifiers 25a to 25f were 2000W on the short sides 5b1, 5b2 side, 2000W, and 25e, 25f on the long sides 5b3, 5b4 side, respectively, 4000W. That is, the total power supplied to the four points (feed points 25a, 25b, 25c, 25d) on the short side 5b1, 5b2 side is 8000 W, and the two points (feed points 25e, 25f) on the long side 5b3, 5b4 side are fed. The total power was set to 8000 W and both were made equal. Under the above conditions, high-frequency power was supplied by the power supply method described in Embodiment 1, and film formation was performed for 20 minutes.

  In this case, as described above, on the axis of symmetry 28, it becomes a node (valley) of the high-frequency electric field of VHF fed from the feeding points 27a, 27b, 27c, and 27d. Therefore, the matchers 26e and 26f connected to the feeding points 27e and 27f are hardly affected by the high frequency electric field of VHF fed from the feeding points 27a, 27b, 27c and 27d. In addition, the matchers 26a, 26b, 26c, and 26d connected to the opposite short sides 5b1 and 5b2 can be matched without being affected by the matching state of the matchers 26e and 26f connected on the symmetry axis 28. It is easy to make the plasma uniform.

  In addition, the matchers 26a and 26b connected to one (short side 5b1) side of the opposing short sides 5b1 and 5b2 and the matchers 26c and 26d connected to the other (short side 5b2) side are fed in reverse phase. Therefore, the matching conditions (matcher circuit constants) of the four matchers 26a to 26d are almost the same. As a result, impedance symmetry as seen from the feeding points 27e and 27f on the symmetry axis 28 is obtained, and matching by the matchers 26e and 26f is facilitated.

  As a result of such an experiment, a silicon-based thin film of 2 μm was deposited on the glass substrate, and the in-plane film thickness distribution was within ± 12% of the average value. Assuming that the formed thin film is used for a solar cell, the crystallization rate of the film estimated by Raman spectroscopy is Ic / Ia = 7.2, which is suitable for a thin film solar cell using microcrystalline silicon. A crystalline silicon thin film was obtained.

  Note that the outputs of the high-frequency amplifiers 25a to 25f are not limited to the above-described values, and the plasma distribution can be changed by changing the respective output values. In addition, the high-frequency power source connected to the opposite short sides 5b1 and 5b2 side is 2 units × 2 (high-frequency power sources 10a to 10d), but in principle, one unit is arranged at a position equidistant from the electrode center C. Alternatively, the equivalent result can be obtained even when two or more units × 2.

  As described above, in the first embodiment, in plasma film forming apparatus 100, two opposite sides (short side 5b1) of electrode 5 are placed on second main surface 5b that is not opposed to stage 2 of electrode 5 (on the atmosphere side). 5b2) is provided with a feeding point for connecting two high-frequency power sources, and the shape formed by the four feeding points 27a to 27d is a square. Further, on the symmetry axis 28 between the feeding points 27a, 27b on one side (short side 5b1) and the feeding points 27c, 27d on the other side (short side 5b2) of the two opposing sides 5b1, 5b2, and four feeding points 27a. Feed points 27e and 27f for connecting two high-frequency power sources are provided at the center of a square formed by ~ 27d, that is, at a position equidistant from the symmetry point C of the four feed points 27a to 27d.

  In this configuration, the phase difference between the high frequency power at one of the two opposite sides (short side 5b1) of the feeding points 27a and 27b and the high frequency power of the other (short side 5b2) feeding points 27c and 27d is fed at 180 degrees. Therefore, a node of the high-frequency electric field distribution formed on the second main surface 5b (on the atmosphere side) of the electrode 5 is formed on the symmetry axis 28 between the feeding points 27a and 27b and the feeding points 27c and 27d. Since high-frequency power is separately fed from the symmetry axis 28 through the feeding points 27e and 27f, the high-frequency power supplies 10e and 10f connected on the symmetry axis 28 are connected to two opposite sides (short sides 5b1 and 5b2). It is difficult to be influenced by the high frequency power supplies 10a to 10d. Further, the high frequency power supplies 10a to 10d connected to the two opposite sides (short sides 5b1 and 5b2) can be easily matched without being affected by the matching state of the high frequency power supplies 10e and 10f connected on the symmetry axis 28. It is. As a result, the V-shaped electric field strength distribution by the feeding points 27a to 27d and the ridge type electric field strength distribution by the feeding points 27e and 27f can be formed independently (stably) and overlapped. It is easy to make the plasma uniform by the power supply point, and uniform film formation on a large-area substrate becomes possible. That is, even when a substrate having a large area is processed by supplying high-frequency power in the VHF band, uniform plasma can be obtained.

  Also, the four feeding points 27a to 27d arranged on the two opposite sides (short sides 5b1, 5b2) are point-symmetrical with respect to the symmetry point C and line-symmetrical with respect to the symmetry axis 28. It is arranged. In addition, the two feeding points 27e and 27f arranged on the opposite two sides (short sides 5b3 and 5b4) are equidistant from the symmetry point C of the four feeding points 27a to 27d, respectively. It is arranged at a position on the symmetry axis 28.

  In this configuration, the matchers 26a and 26b connected to one side (short side 5b1) of the two opposite sides and the matchers 26c and 26d connected to the other side (short side 5b2) are fed in opposite phases. Therefore, the matching conditions (matcher circuit constants) of the four matchers 26a to 26d are almost the same. As a result, impedance symmetry as seen from the feeding points 27e and 27f on the symmetry axis 28 is obtained, and matching by the matchers 26e and 26f is facilitated.

  In the first embodiment, the sum of the high-frequency powers fed to the feeding points 27a to 27d on the opposite two sides (short sides 5b1, 5b2) and the other two sides (short sides 5b3, 5b4). The sum of the high-frequency powers fed to the feeding points 27e and 27f on the same side is equal to each other. As a result, the balance between the V-shaped electric field intensity distribution by the feeding points 27a to 27d and the ridge type electric field intensity distribution by the feeding points 27e and 27f can be improved, so that the plasma is uniformized by a plurality of feeding points. Becomes easier, and uniform film formation on a large-area substrate is facilitated.

Embodiment 2. FIG.
The plasma film-forming apparatus 100 concerning Embodiment 2 is demonstrated. Below, it demonstrates focusing on a different part from Embodiment 1. FIG.

  The plasma film forming apparatus 100 according to the second exemplary embodiment is different from the first exemplary embodiment in operation.

  In the first embodiment, with respect to the electrode 5 shown in FIG. 2, the phase of the high-frequency power in each VHF band fed to the feeding points 27e and 27f on the axis of symmetry 28 is the same as the high-frequency power at the feeding points 27a and 27b. The phase is set.

  On the other hand, in the second embodiment, a phase difference is provided for the high-frequency power in each VHF band that supplies power to the power supply points 27e and 27f. Specifically, the phase adjusters 23e and 23f in the phase shifter 23 generate a phase difference in the high-frequency power (power signal) to be fed to the feeding points 27e and 27f, and the phase difference is temporally changed (modulated). Let At this time, even when the process conditions such as the inter-electrode spacing and the gas pressure are changed, the modulation conditions are adjusted so that a ridge-type electric field intensity distribution having a steeper ridge is obtained according to the changes.

  Thus, in the second embodiment, the high-frequency power supplies 10e and 10f connected on the symmetry axis 28 are obtained so that a ridge-type electric field intensity distribution having a steeper ridge can be obtained in accordance with changes in process conditions. The phase is temporally modulated, and the high-frequency power thus time-modulated by the phase difference is fed to the feeding points 27e and 27f on the symmetry axis. As a result, the ridge-type electric field strength distribution by the feeding points 27e and 27f can be appropriately canceled out from the V-shaped electric field strength distribution by the feeding points 27a to 27d. As a result, the electric field intensity distribution obtained by superimposing the V-shaped electric field intensity distribution by the feeding points 27a to 27d and the ridge type electric field intensity distribution by the feeding points 27e and 27f can be made flatter. The uniformity of the obtained plasma can be further improved.

Embodiment 3 FIG.
The plasma film-forming apparatus 100 concerning Embodiment 3 is demonstrated. Below, it demonstrates focusing on a different part from Embodiment 1. FIG.

  The operation of the plasma film forming apparatus 100 according to the third embodiment is different from that of the first embodiment.

  In the first embodiment, each of the high-frequency power supplies 10a to 10d connected to the opposite short sides 5b1 and 5b2 and the two high-frequency power supplies 10e and 10f connected to the symmetry axis 28 are output. High frequency power is constantly operated to supply power.

  On the other hand, in the third embodiment, four high frequency power supplies 10a to 10d connected to the opposite short sides 5b1 and 5b2 are connected to the electrode 5 shown in FIG. High frequency power is alternately supplied temporally from the two high frequency power supplies 10e and 10f.

  For example, power is supplied as shown in FIG. FIG. 7 shows the on / off state of the high-frequency power with respect to the time axis 71 on the axis 72. In FIG. 7, the operation of the four high-frequency power supplies 10a to 10d connected to the opposite short sides 5b1 and 5b2 is shown by a waveform 73, and the operation of the two high-frequency power supplies 10e and 10f connected on the symmetry axis 28 is shown. Is shown by a waveform 74. The waveform 73 is in an on state during a period in which the waveform 74 is in an off state, and is in an off state in a period in which the waveform 74 is in an on state. The waveform 74 is in an on state during a period in which the waveform 73 is off, and is in an off state in a period in which the waveform 73 is on. The high frequency power supplies 10a to 10d and the high frequency power supplies 10e and 10f are alternately operated.

  As described above, in the third embodiment, four high-frequency power supplies 10a to 10d connected to the opposite two sides (short sides 5b1, 5b2) with respect to the electrode 5 and the other two opposite sides (short). High frequency power is alternately applied temporally from the two high frequency power supplies 10e, 10f connected to the sides 5b3, 5b4). That is, high-frequency power is alternately supplied temporally between the feeding points 27a to 27d on the opposite short sides 5b1, 5b2 side and the feeding points on the opposite long sides 5b3, 5b4 side. Thereby, interference between the V-shaped electric field intensity distribution by the feeding points 27a to 27d and the ridge type electric field intensity distribution by the feeding points 27e and 27f can be reduced. For example, in the period 75 shown in FIG. 7, the four high-frequency power supplies 10a to 10d connected to the two opposite sides (short sides 5b1, 5b2) are connected to the other two sides (short sides 5b3, 5b4). Matching can be easily performed regardless of the matching state of the matchers in the two high-frequency power supplies 10e and 10f connected to the side. This makes it easier to form a V-shaped field strength distribution and a ridge-shaped field strength distribution to be superimposed independently and stably.

  In the third embodiment, as shown in FIG. 7, the on-state period in the waveform 73 and the on-state period in the waveform 74 are equal. As a result, the V-shaped electric field intensity distribution by the feeding points 27a to 27d and the ridge-type electric field intensity distribution by the feeding points 27e and 27f are alternately formed in an equal period. It is possible to improve the balance between the V-shaped electric field intensity distribution by the feeding points 27a to 27d and the ridge type electric field intensity distribution by the feeding points 27e and 27f to be superimposed. As a result, it becomes easier to make the plasma uniform by a plurality of feeding points, and uniform film formation on a large-area substrate is facilitated. That is, in-plane uniformity can be achieved with a time average.

Embodiment 4 FIG.
A plasma film forming apparatus 200 according to the fourth embodiment will be described with reference to FIG. FIG. 8 is a high-frequency power feeding system diagram of the plasma film forming apparatus 200 according to the fourth embodiment. Below, it demonstrates focusing on a different part from Embodiment 1. FIG.

  In the plasma film forming apparatus 200 according to the fourth embodiment, the arrangement configuration of the feeding points 287e, 287f, 287g, and 287h on the opposite long sides 5b3 and 5b4 side in the second main surface 5b of the electrode 5 is the first embodiment. And different.

  In the first embodiment, four high-frequency power sources 10a to 10d are connected to the second short side 5b1 and 5b2 side (feeding points 27a to 27d) facing the second main surface 5b of the electrode 5 shown in FIG. The two high-frequency power supplies 10e and 10f are connected to the symmetry axis 28 (feed points 27e and 27f).

  On the other hand, in the fourth embodiment, as shown in FIG. 8, feed points 287 e, 287 f provided at positions that are equidistant from the symmetry point C and equidistant from the symmetry axis 28 with respect to the electrode 5. High frequency power is supplied from 287g and 287h. That is, the second main surface 5b of the electrode 5 includes a pair of feeding points (a plurality of third feeding points) 287e and 287f arranged on one of the opposing long sides 5b3 and 5b4 (long side 5b3). And a pair of feeding points (a plurality of fourth feeding points) 287g and 287h arranged on the other (long side 5b4). The pair of feeding points 287e and 287f are equidistant from the symmetry point C and are disposed at symmetrical positions with respect to the symmetry axis 28. The pair of feeding points 287 g and 287 h are equidistant from the symmetry point C and are arranged at positions symmetrical with respect to the symmetry axis 28.

  In this case, since the feeding points 287e, 287f, 287g, and 287h arranged on the long sides 5b3 and 5b4 side are not on the symmetry axis 28, an electric field is generated. However, the distances 289e and 289f from the pair of feeding points 287e and 287f to the branch point 288i are set to be equal distances. One set of feeding points 287e and 287f is connected to the high-frequency power source 10e through a branch point 288i that is equidistant from the one set of feeding points 287e and 287f and electrically connects each other. As a result, the electric field by the pair of feeding points 287e and 287f is canceled at the position of the branch point 288i, and the electric field strength becomes almost zero. That is, equivalently, it can be considered that power is supplied to the electrode 5 from the power supply point 227e on the symmetry axis 28 located at the midpoint of the pair of power supply points 287e and 287f.

  Similarly, the distances 289g and 289h from the pair of feeding points 287g and 287h to the branch point 288j are set to be equal distances. One set of feeding points 287g and 287h is connected to the high-frequency power source 10f via a branch point 288j that is equidistant from the one set of feeding points 287g and 287h and electrically connects each other. As a result, the electric field by the pair of feeding points 287g and 287h is canceled at the position of the branch point 288j, and the electric field strength becomes almost zero. That is, equivalently, it can be considered that power is supplied to the electrode 5 from the power supply point 227f on the symmetry axis 28 located at the midpoint of the pair of power supply points 287g and 287h.

  As described above, in the fourth embodiment, as in the first embodiment, the matchers 26e and 26f connected to the equivalent feeding points 227e and 227f are fed from the feeding points 27a, 27b, 27c, and 27d. It is hardly affected by the high frequency power in the VHF band. The matchers 26a, 26b, 26c, and 26d connected to the opposing short sides 5b1 and 5b2 can be matched without being affected by the matching state of the matchers 26e and 26f connected to the equivalent feed points 227e and 227f. . Therefore, according to the fourth embodiment, it is easy to make the plasma uniform by a plurality of feeding points.

  In the fourth embodiment, high-frequency power is fed from one set of feed points 287e and 287f and one set of feed points 287g and 287h across the symmetry axis 28, and thus one set of feed points 287e and 287f and one set. By using the feeding points 287g and 287h, a ridge-type electric field intensity distribution having a steeper ridge can be formed as compared with the first embodiment. As a result, the ridge-type electric field intensity distribution by the one set of feeding points 287e and 287f and the one set of feeding points 287g and 287h is appropriately canceled out from the V-shaped electric field intensity distribution by the feeding points 27a to 27d. It can be. As a result, the electric field intensity distribution obtained by superimposing the V-shaped electric field intensity distribution by the feeding points 27a to 27d and the ridge type electric field intensity distribution by the feeding points 287e to 287h can be made flatter. The uniformity of the obtained plasma can be further improved.

  In this regard, when the inventor conducted an electromagnetic field simulation, the obtained electric field distribution showed an electric field uniformity within the electrode plane of ± 7.8% with respect to the average value. That is, it was confirmed that the uniformity (± 7.8%) of the obtained plasma can be further improved as compared with Embodiment 1 (± 10.8%).

Embodiment 5 FIG.
A plasma film forming apparatus 300 according to the fifth embodiment will be described with reference to FIG. FIG. 9 is a high-frequency power feeding system diagram in the plasma film-forming apparatus 300 according to the fifth embodiment. Below, it demonstrates centering on a different part from Embodiment 4. FIG.

  In the plasma film forming apparatus 300 according to the fifth exemplary embodiment, the arrangement configuration of the feeding points 397e, 397f, 397g, and 397h on the opposite long sides 5b3 and 5b4 side on the second main surface 5b of the electrode 5 is the fourth exemplary embodiment. And different.

  In the fourth embodiment, high frequency power is fed from feeding points 397e, 397f, 397g, and 397h provided at equal distances from the symmetry axis 28 shown in FIG. Further, on the second main surface 5b of the electrode 5, the distance from the feeding points 397e, 397f, 397g, 397h on the opposite long sides 5b3, 5b4 side to the symmetry axis 28 is the feeding on the opposite short sides 5b1, 5b2 side. The distance from the points 27a, 27b, 27c, 27d to the symmetry axis 28 is smaller.

  On the other hand, in the fifth embodiment, as shown in FIG. 9, feeding points 397e, 397f, 397g, and 397h on the opposite long sides 5b3 and 5b4 are provided at positions close to the short sides 5b1 and 5b2. That is, the electrode 5 has a square shape, and one set of feeding points 397e and 397f and one set of feeding points 397g and 397h are arranged at corners of the square. Further, on the second main surface 5b of the electrode 5, the distance from the feeding points 397e, 397f, 397g, 397h on the long side 5b3, 5b4 side (and the short side 5b1, 5b2 side) to the symmetrical axis 28 is relatively It is equal to the distance from the feeding points 27a, 27b, 27c, 27d on the short side 5b1, 5b2 side to the symmetry axis 28.

  In this case, since the feed points 397e, 397f, 397g, and 397h arranged on the long sides 5b3 and 5b4 side are not on the symmetry axis 28, an electric field is generated. However, the distances 399e and 399f from the set of feed points 397e and 397f to the branch point 398i are set to be equal. One set of feed points 397e and 397f is connected to the high frequency power source 10e through a branch point 398i which is equidistant from the set of feed points 397e and 397f and electrically connects each other. As a result, the electric field by the pair of feed points 397e and 397f is canceled at the position of the branch point 398i, and the electric field strength becomes almost zero. That is, equivalently, it can be regarded that power is supplied to the electrode 5 from the power supply point 327e on the axis of symmetry 28 located at the midpoint of the pair of power supply points 397e and 397f.

  Similarly, the distances 399g and 399h from the pair of feeding points 397g and 397h to the branch point 398j are set to be equal distances. One set of feed points 397g, 397h is connected to the high frequency power source 10f via a branch point 398j that is equidistant from the set of feed points 397g, 397h and electrically connects each other. As a result, the electric field generated by the pair of feeding points 397g and 397h is canceled at the position of the branch point 398j, and the electric field intensity becomes substantially zero. That is, equivalently, it can be regarded that power is supplied to the electrode 5 from the power supply point 327f on the symmetry axis 28 located at the midpoint of the pair of power supply points 397g and 397h.

  As described above, in the fifth embodiment, as in the first embodiment, the matchers 26e and 26f connected to the equivalent feeding points 327e and 327f are fed from the feeding points 27a, 27b, 27c, and 27d. It is hardly affected by the high frequency power in the VHF band. Further, the matchers 26a, 26b, 26c, and 26d connected to the opposing short sides 5b1 and 5b2 can be aligned without being affected by the matching state of the matchers 26e and 26f connected to the equivalent feed points 327e and 327f. . Therefore, even in the fifth embodiment, it is easy to make the plasma uniform by a plurality of feeding points.

  In the fifth embodiment, one set of feeding points 397e and 397f and one set of feeding points 397g and 397h are arranged at square corners. Thereby, as compared with the fourth embodiment, high-frequency power is supplied from one set of feed points 397e and 397f and one set of feed points 397g and 397h further away from the symmetry axis 28. Therefore, a ridge-type electric field intensity distribution having a steeper ridge can be formed by the one set of feeding points 397e and 397f and the one set of feeding points 397g and 397h as compared with the fourth embodiment. As a result, the ridge-type electric field intensity distribution by the one set of feeding points 397e, 397f and the one set of feeding points 397g, 397h is appropriately canceled out from the V-shaped electric field intensity distribution by the feeding points 27a to 27d. It can be. As a result, the electric field intensity distribution obtained by superimposing the V-shaped electric field intensity distribution by the feeding points 27a to 27d and the ridge type electric field intensity distribution by the feeding points 397e to 397h can be made flatter. The uniformity of the obtained plasma can be further improved.

  In this regard, the inventor conducted an electromagnetic field simulation. As a result, in the obtained electric field distribution, the electric field uniformity within the electrode surface was ± 6.4% with respect to the average value. That is, it was confirmed that the uniformity (± 6.4%) of the obtained plasma can be further improved as compared with the fourth embodiment (± 7.8%).

In the first to fifth embodiments, numerical values are shown for parameters such as gas flow rate, pressure, and high-frequency power, but these numerical values can be changed as appropriate. Further, although the case of a mixed gas of silane (SiH ₄ ) and hydrogen (H ₂ ) has been described as a film forming gas for forming a silicon thin film, a rare gas such as Ar or Ne may be further added. In addition, an appropriate gas type is selected according to the purpose of the process.

  In the plasma film forming apparatus according to the first to fifth embodiments, the configuration in which the film forming chamber 8 is formed by the vacuum chamber 1 and the electrode 5 is illustrated. The same effect can be obtained by applying the power feeding method as described in the first to fifth embodiments to the configuration in which the electrode 5 and the stage 2 are arranged on the same.

  Further, the plasma film forming apparatus according to the first to fifth embodiments can be applied to, for example, a plasma etching apparatus, an ashing apparatus, a sputtering apparatus, and the like.

  Further, the horizontal film forming chamber 8 has been described above, but the plasma film forming apparatus according to the first to fifth embodiments can be applied to a vertical film forming chamber. Which type of film forming chamber is adopted can be appropriately selected according to the use of the plasma apparatus. The present invention can be variously modified, modified, combined, etc. other than those described above. For example, the second embodiment may be combined with at least one of the third to fifth embodiments. Alternatively, for example, Embodiment 3 may be combined with at least one of Embodiments 2, 4, and 5.

  As described above, the plasma film forming apparatus according to the present invention is useful for an apparatus for forming a thin film such as an amorphous silicon thin film or a microcrystalline silicon thin film on a substrate.

DESCRIPTION OF SYMBOLS 1 Vacuum chamber 2 Stage 3 Exhaust port 4 Insulation flange 5 Electrode 5a 1st main surface 5b 2nd main surface 5b1, 5b2 Short side 5b3, 5b4 Long side 6 Gas supply port 7 Shower plate 8 Deposition chamber 9 Film formation Substrate 10a, 10b, 10c, 10d, 10e, 10f High-frequency power supply 11 Space 21 Signal generator 22 Divider 23 Phaser 23a, 23b, 23c, 23d, 23e, 23f Phase adjustment units 24a, 24b, 24c, 24d, 24e, 24f ON / OFF switcher 25a, 25b, 25c, 25d, 25e, 25f High-frequency amplifier 26a, 26b, 26c, 26d, 26e, 26f Matcher 27a, 27b, 27c, 27d, 27e, 27f Feed point 28, 31 Symmetry axis 100, 200 300 Plasma deposition apparatus 227f, 227e Feed point 28 7e, 287f, 287g, 287h Feed point 288i, 288j Branch point 289e, 289f, 289g, 289h Distance 327f, 327e Feed point 397e, 397f, 397g, 397h Feed point 398i, 398j Branch point 399e, 399f, 399g, 399h Distance C Symmetry point

Claims (7)

A deposition chamber is formed by the vacuum chamber and the first electrode, and a deposition target substrate is placed on the second electrode disposed opposite to the first electrode in the deposition chamber. A plasma film forming apparatus for forming a film using a plasma generated between one electrode and the second electrode,
The first electrode has a square shape;
The second main surface of the first electrode opposite to the first main surface facing the second electrode is:
A plurality of first feeding points arranged on one side of two opposite sides of the square;
A plurality of second feeding points arranged on the other side of the two opposite sides;
At least one third feeding point disposed on one side of the other two opposite sides of the square;
At least one fourth feeding point arranged on the other side of the other two opposite sides;
Have
The plurality of first feeding points and the plurality of second feeding points are arranged at symmetrical positions with respect to a symmetry point and symmetrical with respect to a symmetry axis, and a phase difference of high-frequency power to be fed is determined. 180 degrees from each other,
The at least one third feeding point and the at least one fourth feeding point are respectively arranged at positions that are equidistant from the symmetry point and on the symmetry axis, or from the symmetry point, etc. A plasma film forming apparatus comprising a pair of feeding points which are distances and are arranged symmetrically with respect to the symmetry axis. 2. The plasma component according to claim 1, wherein a phase difference of high-frequency power to be fed is temporally modulated between the at least one third feeding point and the at least one fourth feeding point. Membrane device. The plurality of first feeding points and the plurality of second feeding points and the at least one third feeding point and the at least one fourth feeding point alternately feed high-frequency power in time. The plasma film-forming apparatus according to claim 1, wherein: The at least one third feeding point and the at least one fourth feeding point each include a set of feeding points arranged symmetrically with respect to the symmetry axis;
The one set of feeding points is connected to a high-frequency power source through a branch point that is equidistant from the one set of feeding points and electrically connects each other. 2. The plasma film forming apparatus according to claim 1. The plasma deposition apparatus according to claim 4, wherein the at least one third feeding point and the at least one fourth feeding point are respectively arranged at corners of the square. Power is fed to the sum of high-frequency power fed to the plurality of first feeding points and the plurality of second feeding points, and to the at least one third feeding point and the at least one fourth feeding point. The plasma film forming apparatus according to any one of claims 1 to 5, wherein the sum of the high-frequency powers is equal to each other. A deposition chamber is formed by the vacuum chamber and the first electrode, and a deposition target substrate is placed on the second electrode disposed opposite to the first electrode in the deposition chamber. A plasma film forming method for forming a film using a plasma generated between one electrode and the second electrode,
The first electrode has a square shape;
The second main surface of the first electrode opposite to the first main surface facing the second electrode is:
A plurality of first feeding points arranged on one side of two opposite sides of the square;
A plurality of second feeding points arranged on the other side of the two opposite sides;
At least one third feeding point disposed on one side of the other two opposite sides of the square;
At least one fourth feeding point arranged on the other side of the other two opposite sides;
Have
The plurality of first feeding points and the plurality of second feeding points are arranged at symmetrical positions with respect to a symmetry point and symmetrical with respect to a symmetry axis,
The at least one third feeding point and the at least one fourth feeding point are respectively arranged at positions that are equidistant from the symmetry point and on the symmetry axis, or from the symmetry point, etc. A set of feed points that are distances and located symmetrically with respect to the axis of symmetry;
The plasma film forming method includes:
A first step in which high frequency power is fed to the plurality of first feeding points and the plurality of second feeding points with a phase difference of 180 degrees from each other;
A second step in which high-frequency power is fed to the at least one third feeding point and the at least one fourth feeding point;
The plasma film-forming method characterized by including.