JP4554712B2 - Plasma processing equipment - Google Patents

Description

  The present invention relates to a plasma processing apparatus used in the manufacture of semiconductor elements, flat panel displays, solar cells, and the like, and in particular, improves film formation speed and generates particles even when the film formation area is large. The present invention relates to a plasma processing apparatus that can be suppressed.

Today, flat panel displays such as semiconductor elements, solar cells, or liquid crystal display panels or plasma display panels are manufactured using etching, sputtering, or CVD (Chemical Vapor Deposition), and high-precision processing is performed. ing.
In the manufacture of semiconductor elements, silicon wafers subjected to processing using plasma (plasma processing) and glass substrates used for flat panel displays are becoming larger and larger. Correspondingly, the decompression processing chamber (chamber) of the processing apparatus for performing plasma processing is also enlarged, and in this decompression processing chamber, the molding accuracy of films formed on various substrates such as semiconductor elements or flat panel displays is greatly affected. There is an increasing need to perform uniform plasma processing by uniformly generating reactive species (radicals) or ions in the reactive plasma to be applied.

As an apparatus for manufacturing a large-sized thin film solar cell, for example, an ECR (Electron Cyclotron Resonance) plasma CVD apparatus or an ICP (Inductively Coupled Plasma) plasma apparatus can be used.
However, in order to generate plasma for obtaining a vapor deposition surface having a large area of about 1 m × 1 m, for example, in an ECR plasma CVD apparatus, the arrangement of a magnetic field generating coil used for a cyclotron and an antenna for a radiated radio wave interfere with each other. It is difficult to realize.

Therefore, an antenna for generating plasma that obtains a vapor deposition surface with a large area of about 1 m × 1 m in a plasma CVD apparatus has been proposed (Patent Document 1).
In Patent Document 1, a plurality of antenna elements made of columnar conductors whose surfaces are covered with a dielectric are alternately arranged in parallel and in a plane with the feeding direction reversed, for generating plasma. An antenna is disclosed. By using the antenna for generating plasma of Patent Document 1, plasma with uniform spatial distribution of electromagnetic waves can be generated, and a vapor deposition surface having a large area of about 1 m × 1 m can be obtained.

Next, a conventional plasma CVD apparatus including the array antenna disclosed in Patent Document 1 will be described.
Here, FIG. 5 is a diagram showing a configuration of a conventional plasma CVD apparatus.
A conventional plasma CVD apparatus 100 shown in FIG. 5 includes a control unit 102, a distributor 104, an impedance matching unit 106, and a rectangular parallelepiped reaction vessel 108. The control unit 102 controls each device of the plasma CVD apparatus 100.

An introduction port 110 is formed in the reaction vessel 108, and a film forming gas supply unit 114 is connected to the introduction port 110 through a gas supply pipe 112. For example, when forming a SiO ₂ film, the deposition gas supply unit 114 uses oxygen gas and TEOS (Tetra-Ethyl-Ortho-Silicate) gas (hereinafter referred to as TEOS gas) as the source gas G. ).

  An exhaust port 116 is formed in the lower wall 108b of the reaction vessel 108. A vacuum exhaust unit 120 that evacuates the reaction vessel 108 is connected to the exhaust port 116 via an exhaust pipe 118. The reaction vessel 108 is provided with a pressure sensor (not shown) for measuring the internal pressure.

  In addition, in the reaction vessel 108, a gas radiation plate 122, an antenna array 126 including a plurality of antenna elements 124, and a substrate stage 128 are provided in this order from the upper wall 108a side. A substrate 130 is placed on the surface 128 a of the substrate stage 128.

  The impedance matching unit 106 is connected to the antenna element 124 and corrects an impedance mismatch caused by a change in the load of the antenna element 124 during plasma generation.

The gas radiation plate 122 diffuses the source gas G introduced from the film forming gas supply unit 114 over a wide area, and has a size over the entire area inside the reaction vessel 108. The gas radiating plate 122 partitions the reaction vessel 108 into two spaces. A space on the upper wall 108 a side of the gas radiation plate 122 is a gas dispersion chamber 132, and a space on the lower wall 108 b side of the gas radiation plate 122 is a reaction chamber 134.
The gas radiation plate 122 has a plurality of through holes 122a. The gas radiation plate 122 is made of metal and is grounded.
The substrate stage 128 is provided with a heater (not shown), and this heater is controlled by the control unit 102.

In the conventional plasma CVD apparatus 100, for example, when a SiO ₂ film is formed on the surface 130a of a substrate 130 such as a glass substrate or a silicon wafer, the pressure in the reaction vessel 108 is set to about 1 Pa to several hundreds Pa by the vacuum exhaust unit 120. In addition, by supplying a high-frequency signal to the antenna element 124, electromagnetic waves are radiated around the antenna element 124.
At this time, the source gas G is supplied from the film forming gas supply unit 114 to the gas dispersion chamber 132, and this source gas G flows into the reaction chamber 134 from the through hole 122a at a constant flow rate. Then, the source gas G is ionized, and plasma with a uniform spatial density is generated. Thereby, a SiO ₂ film is formed on the surface 130 a of the substrate 130.
Thus, in the conventional plasma CVD apparatus 100, uniform plasma can be generated. Therefore, even if the area is as large as 1 m × 1 m, an SiO ₂ film can be formed on the surface 130 a of the substrate 130. it can.

JP 2003-86581 A

As described above, the conventional plasma CVD apparatus 100 can form the SiO ₂ film on the surface 130a of the substrate 130 even if the area is large. However, the generated plasma reaches the antenna element 124, that is, the antenna element 124 is disposed in the plasma, and the electric field distribution is extremely high in the vicinity of the surface 124a of the antenna element 124. For this reason, in the vicinity of the surface 124a of the antenna element 124, the source gas G is excessively decomposed by the plasma. Thereby, for example, when an SiO ₂ film is formed on the surface 130 a of the substrate 130, an excessive reaction product such as SiO ₂ is generated by the plasma and does not contribute to the film formation on the surface 124 a of the antenna element 124. Adhesion and further deposition. Thus, there is a problem in that the proportion of SiO ₂ that contributes to the film formation is reduced and the film formation rate is reduced.
Further, when the source gas G is excessively decomposed in the vicinity of the surface 124a of the antenna element 124, there is a possibility that the degree of decomposition of the source gas G becomes non-uniform and sufficient film thickness uniformity cannot be obtained.
Further, there is a problem that SiO ₂ (reaction product) deposited on the surface 124a of the antenna element 124 becomes particles and causes an increase in particles in the processing chamber 134. Due to the increase of the particles, the film quality of the formed film may be deteriorated.

  An object of the present invention is to solve the problems based on the above prior art, improve the film forming speed even when the film forming area is large, suppress the generation of particles, and improve the film quality and film thickness uniformity. An object of the present invention is to provide a plasma processing apparatus capable of forming an excellent film.

In order to achieve the above object, the present invention is a plasma processing apparatus that performs processing on a processing target substrate disposed at a predetermined position using a raw material gas. An antenna element that functions as a monopole antenna , with a length of (2n + 1) / 4 times (n is 0 or a positive integer) the wavelength of the high frequency to be used. A plasma generating unit that generates a plasma using an antenna array that is arranged with a plurality of predetermined gaps, and wherein the plurality of antenna elements are provided vertically above the surface of the substrate to be processed;
Gas radiation provided with a gas radiation plate provided so as to cover the plasma generation unit, spaced apart from the plurality of antenna elements, and having a grounded metal film formed on the surface above the antenna array And
When the antenna element and the radiation plate are viewed from a direction perpendicular to the surface of the processing target substrate disposed at a predetermined position, the radiation plate is aligned with a region between the antenna elements of the plasma generation unit. A plurality of gas discharge ports that are open to the plasma generation unit are formed in the first region, and the gas discharge ports are formed in a second region that matches the region where the antenna element is located, and Provided is a plasma processing apparatus characterized in that the surface of each antenna element and the edge of the gas discharge port closest to the surface of each antenna element are separated by 25% or more of the outer diameter of the antenna element. Is.

In this invention, it is preferable that the said process target board | substrate has a substrate stage arrange | positioned on the surface, and the said substrate stage is provided under the said plasma production | generation part.
Further, in the present invention, a source gas supply unit that supplies the source gas to the gas radiating unit is provided, and the plasma generation unit generates plasma using the antenna array in a state where the source gas is supplied. It is preferable to produce it.
Further, in the present invention, the source gas is, for example, a mixed gas of oxygen gas and TEOS gas.

According to the plasma processing apparatus of the present invention, the gas radiating unit provided so as to cover the plasma generating unit has the plasma in the first region aligned with the region between the antenna elements of the plasma generating unit disposed below. A plurality of gas discharge ports opened to the generation unit are formed, and the gas discharge ports are not formed in the second region aligned with the region where the antenna element of the plasma generation unit is located. When the source gas is supplied from the source gas supply unit to the gas emission plate of the gas emission unit and plasma is generated using the antenna array, the electric field distribution becomes extremely high in the vicinity of the periphery of the surface of the antenna element. However, since the gas discharge port is not formed in the second region aligned with the antenna element, and there is no gas emission port near the periphery of the surface of the antenna element, the source gas is not generated near the periphery of the surface of the antenna element. Not supplied. For this reason, excessive decomposition | disassembly of source gas does not arise and a reaction product is not produced | generated excessively. Thereby, it is suppressed that a reaction product adheres or accumulates on the surface of the antenna element, and generation of particles is suppressed.
Furthermore, according to the plasma processing apparatus of the present invention, the source gas does not decompose excessively in the vicinity of the periphery of the surface of the antenna element, and a reaction product is not generated. The utilization efficiency of the source gas is increased, and the film formation rate is improved. For these reasons, in the present invention, even when the film formation area is large, the film formation rate can be improved and the generation of particles can be suppressed.
Further, according to the plasma processing apparatus of the present invention, since the source gas is not excessively decomposed in the vicinity of the periphery of the surface of the antenna element, the degree of decomposition of the source gas becomes uniform, and sufficient film thickness uniformity is obtained. Obtainable.

It is a figure which shows the structure of the plasma CVD apparatus which concerns on embodiment of the plasma processing apparatus of this invention. It is a typical top view which shows the antenna array of the plasma CVD apparatus of this embodiment. It is a typical top view which shows the arrangement | positioning state of the gas radiation | emission part of the plasma CVD apparatus of this embodiment, and the antenna element of an antenna array. It is a figure which shows the arrangement | positioning state of the gas radiation | emission part of the plasma CVD apparatus of this embodiment, and the antenna element of an antenna array. It is a figure which shows the structure of the conventional plasma CVD apparatus.

Explanation of symbols

10, 100 Plasma CVD equipment (CVD equipment)
DESCRIPTION OF SYMBOLS 12 Control part 14 Distributor 16 Impedance matching device 18 Reaction container 22 Inlet 23 Raw material gas supply pipe 24 Exhaust port 26 Raw material gas supply part 27 Vacuum exhaust part 30 Antenna array 32 Antenna element 33 Gap 34 Substrate stage 36 Substrate 38 Gas dispersion chamber 39 Reaction chamber 40 Gas radiation part 42 Gas radiation plate 44 Gas radiation port G Source gas

Hereinafter, a plasma processing apparatus of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.
FIG. 1 is a diagram showing a configuration of a plasma CVD apparatus according to an embodiment of a plasma processing apparatus of the present invention.

A plasma CVD apparatus 10 (hereinafter referred to as a CVD apparatus 10) shown in FIG. 1 of this embodiment forms a film using, for example, a mixed gas in which two kinds of gases are mixed as the source gas G.
In this embodiment, for two types of gases, oxygen gas is used as the first source gas (active species gas), TEOS gas is used as the second source gas, and a substrate such as a glass substrate or a silicon wafer (processing) A description will be given of an example in which a SiO ₂ film is formed on the surface 36 a of the target substrate 36. In the plasma processing apparatus of the present invention, the number of gases used as the source gas G is not limited to _{two, and the} film formed on the substrate 36 is not limited to the SiO ₂ film. .

  A CVD apparatus 10 shown in FIG. 1 includes a control unit 12, a distributor 14, an impedance matching unit 16, and a rectangular parallelepiped reaction vessel 18. The control unit 12 controls each device of the CVD apparatus 10 as will be described later. The reaction vessel 18 is made of metal or alloy and is grounded.

An inlet 22 for introducing the raw material gas G is formed in the upper wall 18 a of the reaction vessel 18. A raw material gas supply pipe 23 is connected to the introduction port 22. Further, a source gas supply unit 26 is connected to the source gas supply pipe 23.
The source gas supply unit 26 is for supplying source gas G necessary for obtaining a film to be formed on the surface 36 a of the substrate 36 into the reaction vessel 18. For example, when an SiO ₂ film is formed on the surface 36a of the substrate 36, the source gas G is supplied with a mixed gas of oxygen gas (first source gas) and TEOS gas (second source gas). .
The source gas supply unit 26 includes gas cylinders (not shown) corresponding to the types and number of gases corresponding to the film to be formed, and a flow rate adjusting unit (not shown) that adjusts the flow rate of the gas from the gas cylinders. Is provided. In this embodiment, the gas cylinder is filled with oxygen gas (first source gas).
The raw material gas supply unit 26 supplies a TEOS gas with a tank (not shown) filled with a liquid, a vaporization unit (not shown) for vaporizing the liquid, and a gas vaporized by the vaporization unit. A flow rate adjusting unit (not shown) for adjusting the flow rate is provided. In the present embodiment, the tank is filled with liquid TEOS, and is vaporized by the vaporization unit to obtain TEOS gas (second raw material gas). The flow rate adjustment unit adjusts the flow rate of the TEOS gas.
In the present embodiment, a source gas in which oxygen gas (first source gas) and TEOS gas (second source gas) are mixed is supplied from a source gas supply unit 26 to a reaction chamber 39 described later.

  An exhaust port 24 is formed in the lower wall 18 b of the reaction vessel 18. An exhaust pipe 25 is connected to the exhaust port 24. Further, a vacuum exhaust unit 27 is connected to the exhaust pipe 25. The vacuum exhaust unit 27 has a vacuum pump such as a dry pump and a turbo molecular pump. The reaction vessel 18 is provided with a pressure sensor (not shown) for measuring the internal pressure.

  In addition, a substrate stage 34 and a substrate 36 placed on the surface 34 a are provided in the reaction container 18 in order from the lower wall 18 b side, and an antenna array including a plurality of antenna elements 32 is provided above the substrate stage 34. A (plasma generating unit) 30 is provided, and further, a gas radiating unit 40 (gas radiating plate 42) is provided above the antenna array 30 so as to cover the antenna array 30.

Here, FIG. 2 is a schematic plan view showing an antenna array of the plasma CVD apparatus of the present embodiment.
As shown in FIG. 2, the antenna array 30 includes a plurality of predetermined gaps (intervals) 33 in which a plurality of antenna elements 32 are parallel to each other (not shown) substantially parallel to the surface 34 a of the substrate stage 34. Are arranged and arranged. The antenna array 30 is provided on the lower side (the lower wall 18b side) of the gas radiation unit 40. The antenna element 32 is also provided with a predetermined gap 33 with respect to the side walls 18c and 18d. In the present invention, the gap 33 between the antenna element 32 and the side walls 18c and 18d is handled in the same manner as the gap 33 between the antenna elements 32.

  Further, in the antenna array 30, each antenna element 32 is disposed across two opposing side walls 18 c and 18 d of the reaction vessel 18. The antenna array 30 (each antenna element 32) is provided in parallel to the gas radiation plate 42 (see FIG. 1) of the gas radiation section 40 (see FIG. 1) and the surface 34a (see FIG. 1) of the substrate stage 34. ing.

The antenna element 32 is a monopole antenna, and is electrically insulated and attached to openings (not shown) formed in the side walls 18e and 18f of the reaction vessel 18.
As shown in FIG. 2, the antenna array 30 protrudes from the side walls 18e and 18f in the reaction vessel 18 in the opposite directions to the adjacent antenna elements 32, and the feeding direction is opposite. These antenna elements 32 are connected to the impedance matching unit 16 on the high-frequency current supply end side. The impedance matching unit 16 is a matching box.

  The impedance matching unit 16 is used together with adjustment of the frequency of the high-frequency signal generated by the high-frequency power source of the control unit 12 to correct an impedance mismatch caused by a change in the load of the antenna element 32 during plasma generation. Is.

Each antenna element 32 has a rod shape (may be a pipe) made of a conductor having high electrical conductivity, and is (2n + 1) / 4 times the wavelength of the high frequency used (n is 0 or a positive integer). Is the radiation length of the antenna element which is a monopole antenna.
Each antenna element 32 is housed in a cylindrical member 37 made of a dielectric such as quartz, and the surface of each antenna element 32 is covered with a dielectric such as quartz. Thus, the capacity | capacitance and inductance as the antenna element 32 are adjusted by covering a rod-shaped conductor with a dielectric material. Thereby, a high frequency current can be efficiently propagated along the longitudinal direction of the antenna element 32, and an electromagnetic wave can be efficiently radiated. Hereinafter, the surface of the antenna element 32 refers to the surface 37a of the cylindrical member 37, not the surface of the rod-shaped conductor.

  In the present embodiment, the impedance matching device 16 is provided, and as will be described later, the electromagnetic wave formed in a mirror image relationship by grounding the metal film formed on the gas radiating portion 40 (gas radiating plate 42). To form a predetermined electromagnetic wave for each antenna element 32. Furthermore, since the antenna elements 32 constituting the antenna array 30 have the feeding direction opposite to that of the adjacent antenna elements 32, electromagnetic waves are uniformly formed in the reaction chamber 39 described later.

Here, as shown in FIG. 1, in the substrate stage 34, the substrate 36 is placed on the surface 34a as described above. In the substrate stage 34, the substrate 36 is placed with the center of the substrate stage 34 and the center of the substrate 36 aligned with each other.
In addition, a heating element (not shown) for heating the substrate 36 is provided inside the substrate stage 34, and a grounded electrode plate (not shown) is further provided. The heating element is connected to the control unit 12, and heating by the heating element is controlled by the control unit 12.
The electrode plate may be connected to a bias power source (not shown), and a predetermined bias voltage may be applied to the electrode plate by the bias power source.

Further, the gas radiating section 40 shown in FIG. 1 is such that the gas radiating plate 42 has a size over the entire area inside the reaction vessel 18 and is provided so as to cover the antenna array 30. In the present embodiment, the inside of the reaction vessel 18 is partitioned into two spaces by the gas radiating unit 40, and the space on the upper wall 18 a side of the gas radiating unit 40 is the gas dispersion chamber 38. A space on the lower wall 18 b side is a reaction chamber 39.
The gas radiation unit 40 diffuses the gas used for film formation supplied to the gas dispersion chamber 38 into the reaction chamber 39 over a wide area. In the present embodiment, the gas radiating unit 40 diffuses the source gas G (oxygen gas and TEOS gas) introduced from the source gas supply unit 26 into the reaction chamber 39 over a wide area.

Moreover, the gas radiation | emission part 40 is the gas radiation | emission plate 42 which consists of SiC, for example. The through-hole whose diameter is about 0.3 mm-2 mm is formed in multiple numbers. These through holes become the gas discharge ports 44. Further, in the gas radiation portion 40, a metal film is formed on the surface of the gas radiation plate 42 and is grounded.
As shown in FIG. 3, in the gas radiation section 40, the array antenna is viewed from a direction perpendicular to the surface 34a of the substrate stage 34, that is, from a direction perpendicular to the surface of the substrate 36 disposed on the surface 34a of the substrate stage 34. 30 and the gas radiation plate 42, a gas radiation port 44 is formed in a region (second region) 46 in the gas radiation plate 42 that matches the position of the antenna element 32 of the antenna array 30 provided below. It has not been.
In the gas radiating unit 40, when the array antenna 30 and the gas radiating plate 42 are viewed from a direction perpendicular to the surface 34a of the substrate stage 34, a region that does not match the region where the antenna element 32 is located (first region). That is, the radiation port 44 is formed in the formation region (first region) 48 that matches the region of the gap 33 between the antenna element 32 and the antenna element 32.

In the gas radiating unit 40 of the present embodiment, the radiation port 44 is formed in the formation region 48 that matches the gap 33 between the antenna element 32 and the antenna element 32, and the gas radiation port 44 is formed in the region 46 that matches the antenna element 32. 4, the surface of the antenna element 32 such as the space α between the antenna element 32 and the gas radiation plate 42 even when the source gas G is supplied through the gas radiation port 44 as shown in FIG. The source gas G is hardly supplied around 37a. For this reason, although the electric field distribution is extremely high in the vicinity of the periphery of the surface 37a of the antenna element 32, the source gas G is not excessively decomposed by the plasma in the vicinity of the periphery of the antenna element 32. Thereby, even if a reaction product such as SiO ₂ is generated from the source gas G, the amount thereof is small, and the adhesion or deposition on the surface 37a of the antenna element 32 is suppressed.

Further, in the present embodiment, since the source gas G is not excessively decomposed in the vicinity of the periphery of the surface 37a of the antenna element 32, it is suitable for forming a SiO ₂ film formed on the surface 36a of the substrate 36. The ratio of the decomposition gas of the raw material gas G increases, that is, the utilization efficiency of the raw material gas G (oxygen gas and TEOS gas) used for forming the SiO ₂ film formed on the surface 36a of the substrate 36 increases. The film forming speed is also improved.
Furthermore, in the present embodiment, since the source gas G is not excessively decomposed in the vicinity of the periphery of the surface 37a of the antenna element 32, the degree of decomposition of the source gas G becomes uniform and a sufficient film thickness is obtained. Uniformity can be obtained.

  As shown in FIG. 4, the distance β between the surface 37a of the antenna element 32 and the edge closest to the surface 37a of the antenna element 32 of the radiation port 44 is 25% of the outer diameter D of the surface 37a of the antenna element 32. The above is preferable. That is, the width L in the arrangement direction of the antenna elements 32 in the region 46 where the gas radiation port 44 of the gas radiation part 40 is not formed is preferably 150% or more of the outer diameter D.

  Moreover, in the gas radiation part 40 of this embodiment, the arrangement pattern of the gas radiation port 44 in the formation area 48 in which the gas radiation port 44 is formed is not particularly limited. For example, the opening of the gas radiation port 44 close to the antenna element 32 may be reduced to reduce the amount of source gas G supplied near the antenna element 32. Further, the opening shape of the gas radiation port 44 is not particularly limited, and may be circular or quadrangular.

  The control unit 12 has a high-frequency oscillation circuit, a high-frequency power source (not shown) composed of an amplifier, and a current / voltage sensor (not shown), and the oscillation frequency of the high-frequency power source according to the detection signal of the current / voltage sensor. And the adjustment of the impedance matching unit 16 are performed. The control unit 12 controls the frequency of the high-frequency signal common to the antenna elements 32 to bring all the antenna elements 32 close to the impedance-matched state, and thereafter, the impedance matching unit 16 connected to each antenna element 32. Thus, the impedance of each antenna element 32 is individually adjusted. The control unit 12 and the plurality of impedance matching units 16 are connected via a distributor 14. The control unit 12 also controls the feeding of a high frequency signal to the antenna element 32.

The control unit 12 also controls the source gas supply unit 26 and the vacuum exhaust unit 27. The control unit 12 controls the supply timing and flow rate (supply amount) of the source gas G (oxygen gas and TEOS gas) in the source gas supply unit 26.
Further, the control unit 12 controls the vacuum evacuation unit 27 to evacuate the raw material gas and the like in the reaction vessel 18, and further, the pressure in the reaction vessel 18 can be adjusted to a desired pressure. .

In the present embodiment, for example, during the formation of the SiO ₂ film, the source gas G (oxygen gas and TEOS gas) introduced from the source gas supply unit 26 passes through the reaction vessel 18 from the upper wall 18a side to the lower wall 18b. (Hereinafter, the direction from the upper wall 18 a side to the lower wall 18 b side is referred to as “vertical direction”) and is discharged from the exhaust port 24.

  Further, in the present embodiment, the control unit 12 causes the pressure in the reaction vessel 18 to be in a state of about 1 Pa to several hundreds Pa by the vacuum exhaust unit 27, and the source gas G (oxygen gas and TEOS gas) is supplied to the gas radiation plate 42. The gas is supplied from the gas emission port 44. Furthermore, an electromagnetic wave is radiated around the antenna element 32 by feeding a high-frequency signal to the antenna element 32. As a result, plasma (not shown) is generated in the vicinity of the antenna element 32 in the reaction vessel 18, and oxygen gas (active species gas) is excited to obtain oxygen radicals (reactive species). At that time, since the generated plasma has conductivity, the electromagnetic wave radiated from the antenna element 32 is easily reflected by the plasma. For this reason, the electromagnetic wave is localized in a local region around the surface 37 a of the antenna element 32. As described above, in the antenna array 30 having a plurality of antenna elements 32 each formed of a monopole antenna, plasma is localized and formed in the vicinity of the surface 37 a of the antenna element 32, and the electric field distribution around the surface 37 a of the antenna element 32. Becomes extremely high.

  A detailed description of the principle of plasma generation using such an antenna array is described in Japanese Patent Application Laid-Open No. 2003-86581, which is an earlier application by the present applicant. A detailed impedance matching method for each antenna in a plasma generation apparatus using an antenna array is described in Japanese Patent Application No. 2005-014256, which is an earlier application filed by the present applicant. As the antenna array and the detailed impedance matching method for each antenna in the present invention, for example, the methods described in the above specifications may be used.

Next, a film forming method of the CVD apparatus 10 according to the present embodiment will be described using an SiO ₂ film as an example.
First, the source gas G (oxygen gas (active species gas) and TEOS gas) is discharged from the source gas supply unit 26 through the source gas supply pipe 23 to the gas dispersion chamber 38 at a constant flow rate, and communicates with the gas dispersion chamber 38. The source gas G is caused to flow into the reaction chamber 39 from the radiation port 44 at a constant flow rate.
When supplying the source gas G into the reaction vessel 18 (reaction chamber 39), the reaction vessel 18 (reaction chamber 39) is evacuated by the vacuum evacuation unit 27, and the controller 12 (reaction chamber 18) 39) is held at a pressure of about 1 Pa to several hundred Pa, for example. Thereby, the source gas G (oxygen gas and TEOS gas) flows in the vertical direction of the reaction vessel 18 (reaction chamber 39).

Next, a high frequency signal is fed to the antenna element 32 to radiate electromagnetic waves around the antenna element 32. As a result, plasma localized in the vicinity of the antenna element 32 is generated in the reaction chamber 39, and oxygen radicals (active species gas) of the source gas G emitted from the gas discharge ports 44 are excited ( Reactive species). The reaction between the oxygen radical (reactive active species) and the activated TEOS gas proceeds by the active energy of the active oxygen radical (reactive active species), and an SiO ₂ film is formed on the surface 36a of the substrate 36. .

In the film forming method of the present embodiment, the gas radiation port 44 of the gas supply unit 40 is disposed around the surface 37a of the antenna element 32 so that the source gas G is not supplied. In the periphery of 37a, excessive decomposition of the source gas G by the plasma localized in the vicinity of the antenna element 32 is suppressed, and generation of reaction products such as SiO ₂ is suppressed. Accordingly, reaction products such as SiO ₂ is, because it is prevented to adhere or deposit on the surface 37a of the antenna element 32, generation of particles is suppressed. Furthermore, since generation of particles is suppressed, an excellent film quality of the film to be formed (SiO ₂ film) can be obtained.

Further, in the film forming method of the present embodiment, the source gas G is not supplied around the surface 37a of the antenna element 32, and the decomposition of the excess source gas G is suppressed. Since the ratio increases and the ratio (utilization efficiency) of the source gas G (oxygen gas and TEOS gas) used for forming the SiO ₂ film increases, the film forming speed is also improved.
Furthermore, in the present embodiment, since excessive decomposition of the source gas G in the vicinity of the periphery of the surface 37a of the antenna element 32 is suppressed, the degree of decomposition of the source gas G in the reaction chamber 39 becomes uniform, and the substrate Since the decomposition gas suitable for film formation (SiO ₂ film) is uniformly supplied to the surface 36a of 36, the film thickness uniformity of the film (SiO ₂ film) to be formed is also improved.

In the film forming method of the present embodiment, the antenna array 30 can generate uniform plasma even when the substrate 36 is a large one of about 1 m × 1 m, for example. As described above, the generation of particles is suppressed, and the film forming speed is high, so that a SiO ₂ film having excellent film quality and film thickness uniformity can be formed earlier than before.

In the CVD apparatus of this embodiment, the apparatus for forming the SiO ₂ film on the surface 36a of the substrate 36 has been described as an example. However, the plasma processing apparatus of the present invention is not limited to this. The plasma processing apparatus of the present invention can be used to form various films in semiconductor elements, flat display panels such as liquid crystal display panels or plasma display panels, and solar cells. Furthermore, the plasma processing apparatus of the present invention can be used as an etching apparatus, and can also be used for a substrate stage cleaning process.

  Furthermore, in the CVD apparatus of this embodiment, the antenna array 30 in which a plurality of monopole antennas are arranged is used as the plasma generation unit, so that it is localized near the periphery of the surface 37a of the antenna element 32 of the antenna array 30. To generate plasma. With this configuration, the substrate 36 and the antenna array 30 can be arranged relatively close to each other in a state where the plasma is not directly exposed to the substrate 36 placed on the substrate stage 34. As a result, the distance between the antenna array 30 and the substrate 36 can be made sufficiently close to the excitation lifetime of oxygen radicals (reactive active species) excited in the vicinity of the surface 37a of the antenna element 32 of the antenna array 30. It is said. That is, the oxygen radical (reactive active species) can reach the surface 36a of the substrate 36 in a sufficiently excited state.

Furthermore, in the CVD apparatus of the present embodiment, oxygen gas (first source gas) and TEOS gas (second source gas) are used as the source gas G in order to form a SiO ₂ film on the surface 36a of the substrate 36. However, the present invention is not limited to this. The type and number of gases used for the source gas G are appropriately selected according to the type of film to be formed.
In the CVD apparatus of this embodiment, as the first source gas used for the source gas G, a gas that becomes a reactive active species is used, and for example, nitrogen gas, hydrogen gas, and argon gas are used in addition to the oxygen gas. be able to. Further, as the second source gas used for the source gas G, a gas for forming a film other than the first source gas is used. For example, a gas containing a metal compound is used.
For example, when forming a silicon film in the CVD apparatus of this embodiment, as the source gas G, for example, hydrogen gas is used as the first source gas, and silane gas is used as the second source gas, for example. Even in this case, the effect of the present invention can be obtained.

  Although the plasma processing apparatus of the present invention has been described in detail above, the present invention is not limited to the above-described embodiment, and various modifications and changes may be made without departing from the spirit of the present invention. is there.

Claims (4)

A plasma processing apparatus that performs processing on a processing target substrate disposed at a predetermined position using a source gas,
A length of (2n + 1) / 4 times the wavelength of the high frequency used (n is 0 or a positive integer) having a cylindrical dielectric and a rod-shaped conductor surrounded by the dielectric A plurality of antenna elements functioning as monopole antennas are arranged with a predetermined gap, and plasma is generated using an antenna array in which the plurality of antenna elements are provided vertically above the surface of the substrate to be processed. A plasma generating unit,
Gas radiation provided with a gas radiation plate provided so as to cover the plasma generation unit, spaced apart from the plurality of antenna elements, and having a grounded metal film formed on the surface above the antenna array And
When the antenna element and the radiation plate are viewed from a direction perpendicular to the surface of the processing target substrate disposed at a predetermined position,
In the radiation plate, a plurality of gas discharge ports opened to the plasma generation unit are formed in a first region aligned with the region between the antenna elements of the plasma generation unit, and the position of the antenna element The gas discharge port is formed in a second region that is aligned with the region to be connected, and the surface of each of the antenna elements and the edge of the gas discharge port closest to the surface of each of the antenna elements are A plasma processing apparatus characterized by being separated by 25% or more of the outer diameter.   The plasma processing apparatus according to claim 1, wherein the substrate to be processed includes a substrate stage disposed on a surface, and the substrate stage is provided below the plasma generation unit.   2. A source gas supply unit configured to supply the source gas to the gas radiation unit, wherein the plasma generation unit generates plasma using the antenna array in a state where the source gas is supplied. 3. The plasma processing apparatus according to 1 or 2.   The plasma processing apparatus according to claim 1, wherein the source gas is a mixed gas of oxygen gas and TEOS gas.

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