JP2004039844A - Plasma treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma treatment apparatus which can improve the quality of a wafer and uniformly distribute plasma which is generated therein. <P>SOLUTION: An imitation tube having the same shape as a gas feeding tube is arranged in an electrode housing 17, and structures inside the electrode housing are arranged symmetrically to the central point so that the generated plasma can be distributed uniformly. To make short a feedback route of high frequency power, the bottom plate of a matching unit 19 also serves as a top lid 18 of the electrode housing 17. The gas feeding tube in the electrode housing 17 is coiled and used as a coil element in a high frequency power circuit. By inserting a circulator between a high frequency oscillator 23 and the matching unit 19, a reflection wave from the matching unit 19 is transmitted to the ground through a dummy load. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a plasma processing apparatus.
[0002]
[Prior art]
2. Description of the Related Art In a process of manufacturing a semiconductor substrate, a liquid crystal substrate, or the like, a plasma processing apparatus that performs surface treatment on these substrates using plasma is used. Examples of the plasma processing apparatus include a plasma etching apparatus for performing an etching process on a substrate, a plasma CVD apparatus for performing a chemical vapor deposition (CVD) process, and the like. Among the plasma processing apparatuses, a parallel plate type plasma processing apparatus is widely used because of its excellent processing uniformity and relatively simple apparatus configuration.
[0003]
The parallel plate type plasma processing apparatus has a configuration in which two electrode plates facing each other in parallel are provided above and below the chamber. Of the two electrodes, the lower electrode has a mounting table, and is configured to be able to mount the object to be processed. On the other hand, the upper electrode includes an electrode plate having a number of gas holes on a surface facing the lower electrode. The upper electrode is connected to a processing gas supply source. During processing, the processing gas is supplied from the upper electrode side to the space between the upper and lower electrodes (plasma generation space) through a gas hole in the electrode plate. You. The processing gas supplied from the gas hole is turned into plasma by applying high-frequency power to the upper electrode, and this plasma is drawn into the vicinity of the lower electrode to which AC power having a lower frequency than the high-frequency power applied to the upper electrode is applied. It is. Then, a predetermined surface treatment is performed on the target object located near the lower electrode by the drawn plasma.
[0004]
[Problems to be solved by the invention]
In such a plasma processing apparatus, an electrode housing that supports an upper electrode is disposed on a vacuum vessel. This electrode housing also serves as an outer conductor for returning high-frequency power to the ground. Further, an impedance matching device is also arranged on the electrode housing. The electrode housing and the matching box are independent of each other as metal housings, and are opened at the main pole of each metal housing. A power supply rod is disposed in the opening, and high-frequency power supplied from the high-frequency oscillator is supplied to the upper electrode through the power supply rod.
[0005]
Further, inside the electrode housing, a gas supply path, a supply pipe and a discharge pipe for the refrigerant are provided. Further, the electrode housing also houses a high-frequency circuit such as a low-frequency filter for monitoring the DC bias of the high-frequency electrode and a trap for virtually grounding the frequency applied to the opposing electrode.
As described above, the plasma processing apparatus in which a plurality of structures are housed in the electrode housing has various problems.
[0006]
First, if there is a structure inside the electrode housing, the high-frequency electromagnetic field inside the outer conductor is disturbed. When the high-frequency electromagnetic field is disturbed by these structures, the symmetry of the generated plasma is lost, and the plasma generated in the vacuum vessel is unevenly distributed. When the plasma is unevenly distributed, the quality of each element formed on one wafer varies.
[0007]
In addition, if the return path through which the high-frequency power current returns to the ground via the electrode housing and the matching box becomes longer, the impedance increases, the loss of the high-frequency power for plasma generation increases, and the upper electrode of the high-frequency power increases. Supply to the plant decreases.
[0008]
Further, when various things are stored in the electrode housing, it is not easy to secure a place for installing the high-frequency circuit. In particular, the high-frequency circuit is composed of passive elements such as an air-core coil and a capacitor, and the volume and dimensions of the air-core coil are large and require a certain place. For this reason, these circuit components also hinder the securing of installation locations for other structures.
[0009]
Further, if the transmission line from the high-frequency oscillator and the load are not matched, a reflected wave is generated. This reflected wave returns to the high-frequency oscillator and causes inconveniences such as a rise in voltage and an increase in loss, and has a serious influence on the high-frequency oscillator.
[0010]
In order to protect the high-frequency oscillator, when the reflected wave exceeds a specified value, the high-frequency output may be dropped or the output may be temporarily stopped. However, when such control is performed, the generation of plasma becomes temporarily unstable, and the plasma may disappear. Such unstable operation will have a significant effect on wafer quality.
[0011]
The present invention has been made in view of such conventional problems, and has as its object to provide a plasma processing apparatus capable of improving the quality of a wafer.
Another object of the present invention is to provide a plasma processing apparatus capable of uniformly distributing generated plasma.
[0012]
Another object of the present invention is to provide a plasma processing apparatus capable of shortening a current return path.
Another object of the present invention is to provide a plasma processing apparatus capable of easily securing an installation place of a structure in a housing of a plasma generating electrode.
An object of the present invention is to provide a plasma processing apparatus capable of stably generating plasma.
[0013]
[Means for Solving the Problems]
In order to achieve this object, a plasma processing apparatus according to a first aspect of the present invention includes:
A vacuum container for confining plasma, an electrode for applying power for generating plasma to the vacuum container, an inner conductor for supplying power for plasma generation to the electrode, and an outer conductor surrounding the inner conductor. And a conductor, the plasma processing apparatus comprising:
Each structure is arranged symmetrically with respect to an axis passing through the center of the vacuum vessel, the electrode, the inner conductor, and the outer conductor as a center axis.
[0014]
A simulated structure having the same shape as the structure housed in the electrode housing may be arranged at a position symmetrical to the structure with respect to the center axis of symmetry.
The simulated structure may be made of the same material as the structure.
[0015]
The plasma processing apparatus according to the second aspect of the present invention includes:
An electrode for applying power for plasma generation in a vacuum vessel, an electrode housing disposed on the electrode to be an outer conductor of the power for plasma generation, and transmitting power to the electrode and the electrode. And a matching unit that performs impedance matching with the transmission line to be performed.
The matching device is configured such that a bottom portion of the matching device is closed with the upper cover for the electrode housing, and the upper cover for the electrode housing and the bottom plate for the matching device are shared.
[0016]
A plasma processing apparatus according to a third aspect of the present invention includes:
An electrode for applying power for plasma generation in the vacuum vessel, a high-frequency power generated in the electrode, a voltage processing circuit for extracting a DC voltage signal, and a flow path pipe connected to the vacuum vessel, In a plasma processing apparatus provided with
The flow tube is formed as a coil and used as a circuit element of the voltage processing circuit.
[0017]
The flow path pipe may be a gas supply pipe that supplies a processing gas from an external gas supply source into the vacuum vessel.
[0018]
The voltage processing circuit may be a filter circuit in a high-frequency power circuit, and the flow path pipe may be formed as a coil of the filter circuit.
[0019]
The voltage processing circuit is a trap circuit that virtually grounds the frequency of the high-frequency power applied to the opposite electrode of the electrode in the high-frequency power circuit, and the flow path tube is formed as a coil of the trap circuit. You may.
[0020]
The voltage processing circuit may be housed in an outer conductor surrounding the inner conductor.
[0021]
A plasma processing apparatus according to a fourth aspect of the present invention includes:
In a plasma processing apparatus including a matching device that performs impedance matching between an electrode for applying power for plasma generation in a vacuum vessel and a transmission line that transmits power to be applied to the electrode,
A reflected wave that separates a reflected wave reflected from the matching unit to the power supply unit from an incident wave from the power supply unit to the matching unit between a power supply unit that supplies plasma power and the matching unit. It is provided with separation means.
[0022]
The reflected wave separating means may be constituted by a circulator for sending the reflected wave to the ground.
[0023]
The reflected wave separating means may be configured to control the amount of the reflected wave sent to the ground based on the intensity of the reflected wave.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
A plasma processing apparatus according to an embodiment of the present invention will be described below with reference to the drawings. In this embodiment, a plasma CVD (Chemical Vapor Deposition) apparatus will be described as an example of a plasma processing apparatus.
[0025]
(First Embodiment)
In the plasma CVD apparatus according to the first embodiment, the internal structure of the upper electrode housing is configured so that the high-frequency electromagnetic field is not disturbed by the structure inside the upper electrode housing.
[0026]
FIG. 1 shows a configuration of a plasma CVD apparatus 1 according to the first embodiment.
The plasma CVD apparatus 1 according to the first embodiment is configured as a so-called parallel plate type plasma processing apparatus having vertically and vertically opposed electrodes, and SiOF is formed on the surface of a semiconductor wafer (hereinafter, referred to as “wafer”). This is an apparatus for forming a film or the like.
[0027]
The plasma CVD apparatus 1 includes a vacuum vessel 11 and a pump 12.
As the pump 12, a turbo molecular pump or the like is used, and the inside of the vacuum vessel 11 is evacuated to a predetermined reduced pressure atmosphere, for example, a predetermined pressure of 0.01 Pa or less.
[0028]
A shutter 13 is provided on a side of the vacuum vessel 11.
An upper electrode 14 and a lower electrode 15 are arranged inside the vacuum vessel 11.
[0029]
The lower electrode 15 is made of a conductor having a high melting point, such as molybdenum. The wafer is placed on the lower electrode 15 via an insulating material or the like (not shown). A heater (not shown) made of, for example, a nichrome wire is arranged below the lower electrode 15. In addition, the lower electrode 15 is provided with a flow path (not shown) for sending the temperature control refrigerant.
[0030]
The upper electrode 14 is disposed so as to face the lower electrode 15 in parallel, and is supported by a cylindrical electrode housing 17 via an insulating material 16. An upper lid 18 is placed on the electrode housing 17. The electrode housing 17 also functions as an outer conductor for returning high-frequency power to the ground.
[0031]
The plasma CVD apparatus 1 is of a two-frequency excitation type, and includes high-frequency oscillators 23 and 24 for supplying high-frequency power to the upper electrode 14 and the lower electrode 15, respectively.
[0032]
The high-frequency oscillator 23 is a device that outputs high-frequency power having a frequency in the range of 13 to 150 MHz. This high-frequency power is used to generate a high-frequency electric field between the upper electrode 14 and the lower electrode 15 to convert the processing gas supplied from the upper electrode 14 into plasma. The high-frequency oscillator 24 is a device that outputs high-frequency power having a frequency in the range of 0.1 to 13 MHz. This high frequency power is used to draw ions in the plasma toward the lower electrode 15 and control ion energy near the wafer surface. The high-frequency oscillators 23 and 24 are connected to the ground of the plasma CVD device 1. However, the ground of the plasma CVD apparatus 1 can be connected to the ground.
[0033]
Matching devices 19 and 20 are arranged on the upper lid 18 and on the side of the vacuum vessel 11, respectively. The matching units 19 and 20 perform impedance matching between the load and the transmission line in order to prevent generation of a standing wave due to the reflected wave.
[0034]
The upper lid 18 is partially open, and a power supply rod 21 is disposed in this opening. A power supply rod 22 is also interposed between the lower electrode 15 and the matching device 20. The power supply rods 21 and 22 serve as inner conductors for supplying high-frequency power to the upper electrode 14 and the lower electrode 15, respectively.
[0035]
The matching device 19 includes a matching circuit 25 as shown in FIG. Note that the matching device 20 also has a similar matching circuit built therein. One end of the power supply rod 21 is connected to the matching circuit 25 via the output electrode 26. Then, high-frequency power is supplied from the high-frequency oscillator 23 to the upper electrode 14 via the matching circuit 25 and the power supply rod 21.
[0036]
A hollow portion (not shown) for diffusing the processing gas is formed inside the upper electrode 14. An electrode plate 27 made of aluminum or the like is provided on a surface of the upper electrode 14 facing the lower electrode 15. In the electrode plate 27, a gas hole 27a connected to the hollow portion of the upper electrode 14 is formed.
[0037]
Inside the electrode housing 17, a gas supply pipe 28 and a simulation pipe 29 are provided. The gas supply pipe 28 is a pipe for supplying a processing gas from an external processing gas supply source (not shown) to the hollow portion of the upper electrode 14.
[0038]
The processing gas from the processing gas supply source is supplied to the hollow portion of the upper electrode 14 via the gas supply pipe 28, diffused in the hollow portion, and discharged from the gas hole 27a toward the wafer. Various gases can be used as the processing gas. For example, if a SiOF film is to be formed, the conventionally used SiF ₄ , SiH ₄ , O ₂ , NF ₃ , NH ₃ Ar gas can be used as the gas and diluent gas.
[0039]
The simulation tube 29 is provided so that the generated plasma is evenly distributed, and has the same shape as the gas supply tube 28. However, the function of the gas supply pipe 28 such as the passage of the processing gas or the like is not provided in the simulation pipe 29.
[0040]
FIG. 3 shows the inside of the electrode housing 17. FIG. 3 is a view in which the inside of the electrode housing 17 is viewed from above with the matching device 19, the matching circuit 25, and the output electrode portion 26 removed. As shown in FIG. 3, a coolant supply pipe 30 and a coolant discharge pipe 31 are further provided inside the electrode housing 17.
[0041]
The coolant supply pipe 30 is a pipe for sending a coolant for controlling the temperature of the upper electrode 14, and the coolant discharge pipe 31 is a pipe for communicating with the coolant supply pipe 30 and discharging the coolant.
[0042]
The coolant supply pipe 30 and the coolant discharge pipe 31 have the same shape, and the gas supply pipe 28, the simulation pipe 29, the coolant supply pipe 30, and the coolant discharge pipe 31 are symmetric about the center point O. Are located in This center point O is also a point on the center axis of symmetry passing through the centers of the vacuum vessel 11, the upper electrode 14, and the lower electrode 15. The surface treatment, fixing method, and the like of these structures are the same. Further, the high-frequency circuit and the like arranged in the electrode housing 17 are also arranged symmetrically about the center point O, and the vacuum vessel 11 is also symmetrical about the center point O, for example, a columnar shape. To In this way, the vacuum vessel 11, the electrode housing 17, the matching device 19, and all the structures incorporated therein are configured to be symmetric about the center point O.
[0043]
Next, the operation of the plasma CVD apparatus according to the first embodiment will be described.
When the wafer is placed on the lower electrode 15, the wafer is electrostatically attracted by a high-temperature electrostatic chuck (not shown). Next, the shutter 13 is closed, the pump 12 is evacuated, and the inside of the vacuum vessel 11 is set to a predetermined degree of vacuum.
[0044]
In this state, the coolant is caused to flow through the flow path provided in the lower electrode 15, and the temperature of the lower electrode 15 is controlled, for example, to 50 ° C. On the other hand, the air in the vacuum vessel 11 is exhausted by the pump 12, and the inside of the vacuum vessel 11 is set to a high vacuum state, for example, 0.01 Pa.
[0045]
Thereafter, a processing gas such as SiF is supplied from a processing gas supply source. ₄ , SiH ₄ , O ₂ , NF ₃ , NH ₃ Ar gas as a gas and a diluting gas is controlled to a predetermined flow rate by a gas supply pipe 28 and supplied into the vacuum vessel 11 through a hollow portion in the upper electrode 14 and a gas hole 27a of the electrode plate 27. . The processing gas and the carrier gas supplied to the upper electrode 14 are uniformly discharged from the gas holes 27a of the electrode plate 27 toward the wafer.
[0046]
After that, high-frequency power from the high-frequency oscillator 23 is applied to the upper electrode 14 via the matching unit 19 and the power supply rod 21. As a result, a high-frequency electric field is generated between the upper electrode 14 and the lower electrode 15, and the processing gas supplied from the upper electrode 14 is turned into plasma.
[0047]
On the other hand, high-frequency power from the high-frequency oscillator 24 is applied to the lower electrode 15 via the matching unit 20 and the power supply rod 22. As a result, ions in the plasma are drawn toward the lower electrode 15, and the ion energy near the wafer surface is controlled. By applying the high-frequency power to the upper and lower electrodes 14 and 15, plasma of the processing gas is generated, and a chemical reaction on the wafer surface by the plasma forms an SiOF film on the wafer surface.
[0048]
The current due to the high-frequency power from the high-frequency oscillator 23 flows to the ground of the high-frequency oscillator 23 through the inner wall of the electrode housing 17 and the inner wall of the matching device 19. If the current return path is asymmetric about the center point O, the distribution of plasma generated in the vacuum vessel 11 will also be non-uniform. That is, the plasma is unevenly distributed.
[0049]
However, in the plasma CVD apparatus 1, the gas supply pipe 28, the simulation pipe 29, the refrigerant supply pipe 30, and the refrigerant discharge pipe 31 are placed inside the electrode housing 17 so as to be symmetric about the center point O. Are located. The vacuum vessel 11, the electrode housing 17, the matching box 19, and all the structures contained therein, including these tubes, also have symmetry about the center point O. For this reason, the generated plasma is not biased to one location, and the distribution of the plasma also has symmetry about the center point O, and is uniformly distributed in the vacuum chamber 11.
[0050]
As described above, according to the present embodiment, the simulation tube 29 having the same shape and the same material as the gas supply tube 28 is provided inside the electrode housing 17, and the structure inside the electrode housing 17 is They are arranged symmetrically about the center point O. Therefore, the plasma generated in the vacuum chamber 11 can be uniformly distributed, and the quality of each chip formed on the wafer can be uniform.
[0051]
In this embodiment, only one simulation tube is provided. However, the number is not limited to one, and a simulation tube can be provided according to the number of structures in the electrode housing. In addition, the gas supply pipe, the refrigerant supply pipe, and the refrigerant discharge pipe formed of the same shape and the same material are arranged in three directions so as to be symmetrical about the center point O without disposing the simulation pipe. You can also.
[0052]
(Second embodiment)
The plasma CVD apparatus according to the second embodiment is configured so that the return path of high-frequency power inside the electrode housing of the upper electrode and the matching box is shortened in order to reduce power loss.
[0053]
FIG. 4 shows a configuration of a plasma CVD apparatus 1 according to the second embodiment.
The plasma CVD apparatus 1 according to the second embodiment has a configuration in which the bottom plate 41 of the matching box 19 also serves as the upper lid 18 of the electrode housing 17.
[0054]
As shown in FIG. 5, a groove is provided on the end surface of the electrode housing 17 which is in close contact with the upper lid 18, and a gasket 42 for preventing high-frequency leakage having elasticity is arranged in the groove. The electrode housing 17 and the upper lid 18 are fastened with screws or the like. As a result, the gasket 42 is deformed and closes the gap between the electrode housing 17 and the matching device 19.
[0055]
A groove is also provided on an end face of the upper lid 18 which is in close contact with the matching device 19, and a gasket 43 for preventing high-frequency leakage having elasticity is arranged in this groove. Then, by fastening the upper cover 18 and the matching device 19 with screws or the like, the gasket 43 is deformed, and the gap between the upper cover 18 and the matching device 19 is closed.
[0056]
Thus, the insides of the electrode housing 17 and the upper lid 18 are sealed. The high-frequency power returns to the high-frequency oscillator 23 through the sealed electrode housing 17, the upper lid 18, and the inner wall of the matching box 19, as indicated by arrows in the drawing.
[0057]
In the conventional plasma CVD apparatus, as shown in FIG. 6, the bottom plate 41 of the matching device 19 is provided separately from the upper lid 18 of the electrode housing 17. In the conventional plasma CVD apparatus, as shown by the arrow in FIG. 7, the high-frequency power returns to the high-frequency oscillator 23 via the bottom plate 41 of the matching unit 19 after passing through the electrode housing 17 and the upper cover 18. For this reason, in the conventional plasma CVD apparatus, the return path becomes longer by the length of the bottom plate 41 of the matching device 19.
[0058]
However, in the plasma CVD apparatus 1 according to the present embodiment, since the bottom plate 41 of the matching device 19 also serves as the upper cover 18 of the electrode housing 17, the return path is shorter than that of the conventional device. When the return path of the high-frequency power becomes short, the impedance decreases, and the loss of the high-frequency power decreases. Therefore, the operation of the plasma CVD apparatus 1 is stabilized.
[0059]
(Third embodiment)
In the plasma CVD apparatus according to the third embodiment, a gas supply pipe as a structure in the electrode housing is used as a coil element of a high-frequency power circuit in order to easily secure an installation place inside the electrode housing. It was made.
[0060]
FIG. 8 shows a configuration of a plasma CVD apparatus according to the third embodiment.
The high-frequency oscillator 23 is supplied with power from the high-frequency oscillator 23 to the upper electrode 14 as being biased with direct current.
[0061]
A low-pass filter is constituted by the gas supply pipe 28 and the dielectric 51 as a high-frequency power circuit. The gas supply pipe 28 is wound in a coil shape. The gas supply pipe 28 is usually a metal pipe, and is preferably used for a coil element of a high-frequency power circuit. However, the above-mentioned refrigerant supply pipe 30 and refrigerant discharge pipe 31 may be wound into a coil shape and used as a coil element.
[0062]
Also, a dielectric 51 is interposed between the other end of the gas supply pipe 28 and the electrode housing 17 to insulate it from the ground potential. The other end of the gas supply pipe 28 is connected to a covered wire 52 made of an insulating material. The covered wire 52 extends to the outside of the electrode housing 17 and is connected to an external DC detection circuit. Note that polytetrafluoroethylene or the like is used as a covering material of the covered wire 52. An insulating material 53 is interposed between the covered wire 52 and the electrode housing 17 so that the inside of the electrode housing 17 is sealed, and the covered wire 52 is supported by the insulating material 53.
[0063]
FIG. 9 shows an equivalent circuit of such a configuration.
The gas supply pipe 28 and the dielectric 51 function as an inductance and a capacitor, respectively, and the gas supply pipe 28 and the dielectric 51 constitute a low-pass filter. This low-pass filter is formed on the upper electrode 14, and high-frequency power is supplied from the high-frequency oscillator 23 to the upper electrode 14. The DC component of the high-frequency power passes through the low-pass filter and is output to the DC detection circuit via the covered wire 52.
[0064]
As described above, a coil having a large volume and a large size can be used also as the gas supply pipe 28, so that it is easy to secure an installation place inside the electrode housing 17, and it is also possible to secure an installation place for other structures.
[0065]
The gas supply pipe 28 can be used not only as a low-pass filter but also as a trap circuit for guiding the upper electrode 14 to virtual ground for the frequency of the high-frequency power applied to the lower electrode 15.
[0066]
(Fourth embodiment)
In the plasma CVD apparatus according to the fourth embodiment, a circulator is inserted between the high-frequency oscillator and the matching device so that the operation of the high-frequency oscillator does not become unstable due to the generated reflected wave. It was made.
[0067]
FIG. 10 shows a configuration of a plasma CVD apparatus according to the fourth embodiment.
In the plasma CVD apparatus according to the fourth embodiment, a circulator 61 is interposed between the high-frequency oscillator 23 and the matching device 19.
[0068]
The circulator 61 has a characteristic that an input from a certain input / output port is output only to a port in a certain direction when another input / output port is matched. The circulator 61 includes a ferrite element or the like, and the circulator 61 has such characteristics by applying a magnetic field to the ferrite element.
[0069]
A pseudo load 62 for matching is connected to one end of the circulator 61. The other end of the dummy load 62 is grounded. In addition, an effective value monitor 63 is interposed between the matching unit 19 and the circulator 61. The effective value monitor 63 detects the difference between the incident wave and the reflected wave, and supplies a monitor signal monitoring the difference between the incident wave and the reflected wave to the high-frequency oscillator 23. The high-frequency oscillator 23 feeds back the monitor signal and controls the difference between the incident wave and the reflected wave to be constant.
The circulator can be inserted between the high-frequency oscillator 24 and the matching device 20.
[0070]
Next, the operation of the plasma CVD apparatus 1 according to the fourth embodiment will be described.
The incident wave from the high-frequency oscillator 23 is input to the circulator 61. Circulator 61 outputs the incident wave to matching device 19. If there is no matching between the load 64 on the upper electrode 14 side and the transmission line, a reflected wave is transmitted from the matching unit 19 to the high-frequency oscillator 23.
[0071]
As shown in FIG. 11, if the circulator 61 is not provided, the reflected wave from the matching device 19 is transmitted to the high-frequency oscillator 23 and has a great influence on the high-frequency oscillator 23.
[0072]
However, if the circulator 61 is provided between the high-frequency oscillator 23 and the matching device 19 as shown in FIG. 10, the reflected wave from the matching device 19 is input to the circulator 61 and separated from the incident wave. . The circulator 61 supplies the reflected wave to the dummy load 62. The reflected wave is transmitted to ground via the dummy load 62. The effective value monitor 63 monitors the difference between the incident wave and the reflected wave. The high-frequency oscillator 23 controls the difference between the incident wave and the reflected wave based on the monitor signal of the effective value monitor 63 so as to be constant.
[0073]
Since the circulator 61 is interposed between the high-frequency oscillator 23 and the matching device 19 in this manner, there is no need to newly provide protection means for the reflected wave of the high-frequency oscillator 23, and the reflected wave is Will not return to. Therefore, the operation of the high-frequency oscillator 23 is stabilized without dripping or suspending the high-frequency power. Therefore, plasma is generated stably, and the quality of the wafer can be maintained.
[0074]
Note that the effective value monitor 63 can be omitted by making the amount of incident wave transmitted to the load 64 constant.
[0075]
In carrying out the present invention, various modes are conceivable, and the present invention is not limited to the above embodiments.
For example, the object to be processed is not limited to a semiconductor wafer, and may be used for a liquid crystal display device or the like. The film to be formed is SiO ₂ , SiN, SiC, SiCOH, CF film and the like.
[0076]
Further, the plasma treatment performed on the object to be processed can be used not only for the film formation process but also for an etching process or the like. Furthermore, the plasma processing apparatus is not limited to the parallel plate type, but may be any type of plasma processing apparatus having an electrode in a chamber, such as a magnetron type.
[0077]
Further, the plasma CVD apparatus can be configured by appropriately combining the first to fourth embodiments.
[0078]
【The invention's effect】
As described above, according to the present invention, the quality of a wafer can be improved.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional view illustrating a configuration of a plasma CVD apparatus according to a first embodiment of the present invention.
FIG. 2 is a sectional view showing the inside of the electrode housing and the like in FIG. 1;
FIG. 3 is a plan view showing the inside of an electrode housing.
FIG. 4 is a cross-sectional view showing the inside of an electrode housing and the like of a plasma CVD apparatus according to a second embodiment.
FIG. 5 is an enlarged sectional view of FIG.
FIG. 6 is a cross-sectional view showing the inside of an electrode housing and the like of a conventional plasma CVD apparatus.
FIG. 7 is an enlarged sectional view of FIG. 6;
FIG. 8 is a sectional view showing the inside of an electrode housing of a plasma CVD apparatus according to a third embodiment.
FIG. 9 is a circuit diagram showing an equivalent circuit of FIG. 8;
FIG. 10 is an explanatory diagram illustrating a configuration of a plasma CVD apparatus according to a fourth embodiment.
FIG. 11 is an explanatory view showing a configuration of a conventional plasma CVD apparatus.
[Explanation of symbols]
1 Plasma CVD equipment
11 Vacuum container
12 pumps
13 Shutter
14 Upper electrode
17 Electrode housing
18 Top lid
19 Matching device
28 Gas supply pipe
61 circulator

Claims (12)

A vacuum container for confining plasma, an electrode for applying power for generating plasma to the vacuum container, an inner conductor for supplying power for plasma generation to the electrode, and an outer conductor surrounding the inner conductor. And a conductor, the plasma processing apparatus comprising:
With the axis passing through the center of the vacuum vessel, the electrode, the inner conductor, and the outer conductor as a center axis, the respective structures were arranged to be symmetrical,
A plasma processing apparatus characterized by the above-mentioned. A simulated structure having the same shape as the structure housed inside the electrode housing was arranged at a position symmetrical to the structure with respect to the center axis of symmetry,
The plasma processing apparatus according to claim 1, wherein: The simulated structure is made of the same material as the structure,
3. The plasma processing apparatus according to claim 2, wherein: An electrode for applying power for plasma generation in a vacuum vessel, an electrode housing disposed on the electrode to be an outer conductor of the power for plasma generation, and transmitting power to the electrode and the electrode. And a matching unit that performs impedance matching with the transmission line to be performed.
The bottom of the matching box is closed with the top lid for the electrode housing, and the top lid for the electrode housing and the bottom plate for the matching box are configured to be shared.
A plasma processing apparatus characterized by the above-mentioned. An electrode for applying power for plasma generation in the vacuum vessel, a high-frequency power generated in the electrode, a voltage processing circuit for extracting a DC voltage signal, and a flow path pipe connected to the vacuum vessel, In a plasma processing apparatus provided with
The flow path tube was formed as a coil, and used as a circuit element of the voltage processing circuit.
A plasma processing apparatus characterized by the above-mentioned. The flow path pipe is a gas supply pipe that supplies a processing gas from an external gas supply source into the vacuum vessel.
The plasma processing apparatus according to claim 5, wherein: The voltage processing circuit is a filter circuit in a high-frequency power circuit, the flow path tube is formed as a coil of the filter circuit,
7. The plasma processing apparatus according to claim 5, wherein: The voltage processing circuit is a trap circuit that is virtually grounded with respect to the frequency of the high-frequency power applied to the counter electrode of the electrode in the high-frequency power circuit, and the flow path tube is formed as a coil of the trap circuit. ,
7. The plasma processing apparatus according to claim 5, wherein: The voltage processing circuit is housed in an outer conductor surrounding the inner conductor,
The plasma processing apparatus according to any one of claims 5 to 8, wherein: In a plasma processing apparatus including a matching device that performs impedance matching between an electrode for applying power for plasma generation in a vacuum vessel and a transmission line that transmits power to be applied to the electrode,
A reflected wave that separates a reflected wave reflected from the matching unit to the power supply unit from an incident wave from the power supply unit to the matching unit between a power supply unit that supplies plasma power and the matching unit. With separation means,
A plasma processing apparatus characterized by the above-mentioned. The reflected wave separating means is constituted by a circulator that sends the reflected wave to the ground,
The plasma processing apparatus according to claim 10, wherein: The reflected wave separation means is configured to control the amount of the reflected wave sent to the ground based on the intensity of the reflected wave.
The plasma processing apparatus according to claim 11, wherein:

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