JP2006294483A - Plasma processing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma processing device capable of processing large-sized object to be processed like a board having a diameter of not less than 300 mm, capable of generating uniform plasma with low plasma potential and high density. <P>SOLUTION: The plasma processing device is composed of a plasma generation chamber 1 hoising a substance to be processed, a flux path structural body 5 having at least a pair of end faces 5a, 5b facing each other, an antenna coil 11 wound around the flux path structural body 5, and a high frequency generation source supplying high frequency current to the antenna coil 11. The plasma generation chamber 1 is arranged between the end faces 5a, 5b. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a plasma processing apparatus for processing a large substrate and the like, and in particular, a dry etching apparatus for processing a large diameter wafer having a diameter of 300 mm or more, a large area flat panel display, a sheet-like material, and the like. The present invention relates to a plasma processing apparatus that can be suitably applied to a CVD apparatus, a sputtering apparatus, an ion beam apparatus, and the like.

  2. Description of the Related Art Conventionally, techniques for depositing and etching thin films using the physical and chemical properties of plasma have been applied to semiconductor device manufacturing apparatuses and plasma display manufacturing apparatuses. Non-Patent Document 1 discloses an example of a general plasma generation apparatus. The plasma generation apparatus described in Non-Patent Document 1 has a coiled antenna arranged outside the plasma generation chamber, and generates plasma in the plasma generation chamber by flowing a high-frequency current through the antenna. To do. In this example, a cylindrical helical coil or a planar spiral coil is used as the antenna. In this plasma generation apparatus, the antenna is disposed outside the plasma generation chamber, but there is a type in which the antenna is disposed inside the plasma generation chamber. Both types have the same principle for generating plasma.

The above-described plasma generation apparatus that allows a high-frequency current to flow through a coiled antenna can generate high-density plasma with a plasma density of 10 ¹¹ / cm ³ or more, despite its simple structure. The speed is obtained, and as a result, the machining time can be shortened, so that it is widely used in the industry.

  In general, high-frequency discharge without a magnetic field is classified into electric field type discharge (E discharge) and magnetic field type discharge (H discharge). The former is discharged by an electrostatic field E formed by the charge on the antenna surface, and the plasma generated by this discharge is called capacitively coupled plasma (or electrostatically coupled plasma). For example, plasma generated by applying a high frequency voltage to two parallel plate electrodes is this capacitively coupled plasma. On the other hand, the latter discharges by a magnetic field H generated by the current flowing through the antenna, and the plasma generated by this discharge is called dielectric coupled plasma. The plasma generated by the above-described plasma generation apparatus using the coiled antenna mainly uses this dielectric coupled plasma.

Here, the principle of generating inductively coupled plasma will be described with reference to the plasma generating apparatus using a planar spiral coil. When a high frequency current is passed through the coil, a high frequency magnetic field is generated around the coil according to Ampere's law (Equation 1).
∇ × H = J + ∂D / ∂t (Formula 1)
Where H: magnetic field, J: current density, D: displacement current

As can be seen from the following (Equation 2), the high-frequency magnetic field H brings about a change with time in the magnetic flux density in the plasma generation chamber. Further, according to Faraday's law of electromagnetic induction (Equation 3), a change in magnetic flux density causes a change in electric field. The electric field accelerates electrons in the plasma generation chamber.
B = μH (Formula 2)
∇ × E = −∂B / ∂t (Formula 3)
Where B: magnetic flux density, μ: magnetic permeability of the medium in the plasma generation chamber (= μ _r μ ₀ ≈μ ₀ , μ _r : relative magnetic permeability, μ ₀ : vacuum magnetic permeability), E: electric field

  In this way, the electrons in the plasma generation chamber rotate in the direction opposite to the direction of the current flowing through the spiral coil so as to cancel the magnetic field generated by the current flowing through the spiral coil. Then, the electrons moving in the circumferential direction of the plasma generating apparatus collide with gas molecules and atoms, whereby dissociation and ionization occur, and plasma is generated and maintained.

  Recently, with the increase in the scale of integrated circuits of semiconductor devices, the dimensions of high-performance semiconductor chips to be manufactured have increased. In semiconductor devices, increasing the diameter of a Si wafer can increase the number of semiconductor chips that can be cut out from a single Si wafer, and the area of unusable cut ends can be made relatively small, thereby reducing costs. . Therefore, it is desired to further increase the diameter of the Si wafer, and the flat panel display is steadily increasing in size. In general, in substrate processing including a vacuum process, the evacuation time, the open time to the atmosphere, and the process time are long, so that the processing cost is lower as the area of the substrate that can be processed per process is larger.

On the other hand, in a plasma processing apparatus using inductively coupled plasma, when the substrate becomes large, the length of the antenna coil must be increased in order to widen a uniform plasma generation space. However, when the length of the coil is increased, the voltage at the power supply side terminal of the coil is increased to several kV or more, so that capacitive coupling occurs between the coil and the plasma. When such capacitive coupling occurs, electrons in the plasma are attracted to the antenna coil by an electrostatic field, and the amount of electrons killed by colliding with the wall of the plasma generation chamber increases. As a result, since the electron density in the plasma is lowered, there is a problem that the amount of radicals and ions generated is reduced and the processing time is increased. Moreover, when the electron density near the wall of the plasma generation chamber decreases, the balance between the positive charge and the negative charge is lost, and the positive charge density is relatively higher than the electron density. Then, from Poisson's equation (Equation 4), a space potential is formed by positive ions, and the plasma potential is increased, that is, the sheath voltage is increased.
∇ ² V = ρ / ε ₀ (Formula 4)
However, V: space potential, ρ: charge density, ε ₀ : vacuum permittivity For this reason, positive ions collide with the wall of the plasma generation chamber toward the antenna coil, and atoms and molecules on the wall are sputtered. As a result, there is a problem of contaminating the substrate and other objects to be processed. Furthermore, radicals attached to the wall are re-desorbed by positive ion collision and disturb the plasma composition, but the type and thickness of the substance attached to the wall depends on the operating history of the device and the temperature of the wall. Therefore, even if the process control parameter is the same, there is a problem that the processing result is different and the variation between lots is increased.

  Patent Document 2 discloses an inductively coupled plasma generation apparatus having a magnetic path structure configured to guide magnetic flux lines of a high-frequency magnetic field from the upper surface to the side surface of a plasma generation chamber. In this plasma generation apparatus, the magnetic flux lines are guided from the upper surface of the plasma generation chamber to the side surfaces, and the magnetic flux lines pass through the side surface return portion and the upper surface return portion (the back surface return portion in Patent Document 2) which are return paths. To return to the top. This makes it possible to form uniform plasma over a wide area. However, in general, the magnetic flux density concentrates where the gap of the magnetic path structure is small, so the magnetic flux density where the gap is large is low. Therefore, in the configuration of this plasma generation apparatus, the plasma density in the peripheral part of the plasma generation chamber is relatively high and the plasma density in the central part is low. For this reason, it has been difficult to simultaneously realize expansion of the plasma region and formation of uniform plasma.

Edited by Hideo Sakurai, “Plasma Electronics”, Ohmsha, August 25, 2000, p. 116-117 JP 2003-323998 A

  The present invention has been made in view of the above-described conventional problems, and can process large-sized objects such as a circular substrate having a diameter of 300 mm or more, a rectangular substrate having a side length of 300 mm or more, and a roll sheet having a width of 300 mm or more. It is another object of the present invention to provide a plasma processing apparatus that can generate uniform plasma with low plasma potential.

  In order to achieve the above-described object, the present invention provides a plasma generation chamber in which an object to be processed is accommodated, a magnetic path structure having at least one pair of end faces facing each other, and a magnetic path structure wound around the magnetic path structure. There is provided a plasma processing apparatus comprising: an antenna coil; and a high-frequency generation source for supplying a high-frequency current to the antenna coil, wherein the plasma generation chamber is disposed between the end faces.

In a preferred aspect of the present invention, the object to be processed is configured to be arranged in parallel with the end face.
In a preferred aspect of the present invention, the plasma density distribution in the plasma generation chamber is controlled by locally adjusting the distance between the end faces.
In a preferred aspect of the present invention, the height of the plasma generation chamber is 1 mm or more and 10 mm or less.
The magnetic resistance of the air gap increases in proportion to the distance between the end faces (the size of the air gap). By reducing the height of the plasma generation chamber to 1 mm or more and 10 mm or less, the magnetic field generated by the antenna coil can be efficiently transmitted to the plasma generation chamber. Therefore, a high plasma density can be obtained and a high substrate processing speed can be obtained.

  According to the present invention, a high-frequency magnetic field is generated inside the antenna coil by flowing a high-frequency current through the antenna coil, and this high-frequency magnetic field is transmitted through the magnetic path structure to the plasma generation chamber. In the plasma generation chamber, an electric field induced by the high-frequency magnetic field accelerates electrons in the plasma generation chamber, thereby generating a stable plasma with a uniform density.

  In the present invention, only the high-frequency magnetic field passes through the magnetic path structure, and almost no potential difference is generated between the end faces of the magnetic path structure. Therefore, only the magnetic flux density changes between the end faces of the magnetic path structure, and the electric field hardly changes. For this reason, inductively coupled plasma is generated in the plasma generation chamber by an electric field induced by a change in magnetic flux density. Since this plasma is not electrostatically coupled to the magnetic path structure, electrons do not collide with the wall of the plasma generation chamber, so the number of killed electrons is greatly reduced, and the power supplied to the antenna coil from the high-frequency source is plasma. Can be used effectively for generation. In addition, since the plasma potential can be kept low and stable, positive ions do not collide with the wall of the plasma generation chamber, causing problems such as substrate contamination due to spatter from the wall surface material and wall surface deposits, and re-desorbed radicals. The problem of increased variation between lots can be suppressed.

  Further, if the area of the end face of the magnetic path structure is increased, a large-area plasma can be easily generated. If both end faces of the magnetic path structure are parallel, a uniform magnetic field is created in the gap between the end faces, so that a uniform plasma with a large area can be created. Furthermore, the plasma density distribution in the plasma generation chamber can also be controlled by locally adjusting the distance between the end faces (the size of the air gap). That is, by finely adjusting the shape of the end face, the plasma density uniformity can be further improved over a large area, and plasma can be generated locally in the plasma generation chamber. It is also possible to provide a density gradient in the density distribution.

In a preferred aspect of the present invention, the end surface constitutes a wall surface of the plasma generation chamber.
According to the present invention, the distance between the end faces (the size of the gap) can be reduced, so that the magnetic flux density can be increased.

In a preferred aspect of the present invention, the apparatus further includes an electron supply mechanism for supplying electrons to the plasma generation chamber when a high-frequency current is supplied to the antenna coil.
In the plasma generating apparatus described in Non-Patent Document 1 described above, when electric power is applied to the antenna coil, electrons are capacitively coupled to the antenna coil, and high energy electrons collide with the wall surface of the plasma generating chamber. As a result, a large amount of secondary electrons are generated, and the plasma is easily ignited. On the other hand, capacitively coupled plasma does not occur in a plasma generation apparatus that employs a system in which only a high-frequency magnetic field is introduced from an antenna coil into the plasma generation chamber. Therefore, immediately after power is applied to the antenna coil, a very small number of electrons in the plasma generation chamber are inductively coupled and rotate in a radial electric field, but at this time, the collision frequency between electrons and gas molecules is small. Sufficient electron avalanche does not occur and stable discharge may not be achieved. According to the present invention, by supplying a large amount of electrons to the plasma generation chamber when supplying a high-frequency current, the number of electrons generated by colliding with gas molecules is larger than the number of electrons colliding with the wall and killed. This can cause a stable discharge. Thereafter, stable plasma can be maintained even if the electron supply from the electron supply mechanism is stopped.

  As described above, according to the present invention, it is possible to generate a uniform plasma having a low plasma potential over a wide region. Therefore, a large-area substrate having a dimension of 300 mm or more can be processed.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a perspective view showing an embodiment of an inductively coupled plasma processing apparatus according to the present invention. FIG. 2 is a cross-sectional view of the plasma processing apparatus shown in FIG. 3 is a cross-sectional view taken along line III-III in FIG.
As shown in FIGS. 1 to 3, this plasma processing apparatus includes a vacuum chamber 3 having a plasma generation chamber 1 and two roller chambers 2A and 2B, and a U-shaped magnet arranged so as to sandwich the plasma generation chamber 1. The road structure 5 is provided. The plasma generation chamber 1 is located between the roller chambers 2A and 2B, and the plasma chamber and these roller chambers 2A and 2B communicate with each other. The plasma generation chamber 1 has a flat shape, and its height is 1 mm or more and 10 mm or less. A feed roller 6 and a take-up roller 7 are arranged in the roller chambers 2A and 2B, respectively, and a sheet material (object to be processed) 10 fed from the feed roller 6 passes through the plasma generation chamber 1 and is taken up. It is designed to be wound up by In this embodiment, the sheet material 10 is a plastic film, and the width is about 1 m.

  The magnetic path structure 5 is made of a magnetic material such as ferrite. As shown in FIG. 1, the magnetic path structure 5 is basically composed of a columnar center portion 5C and arm portions 5A and 5B extending in parallel from both ends of the center portion 5C. Both end faces (end faces of the arm portions 5A and 5B) 5a and 5b of the magnetic path structure 5 are opposed to each other in parallel, and the size of the gap (distance between the end faces 5a and 5b) is 30 mm. The plasma generation chamber 1 is located between the end surfaces 5a and 5b, and the plasma generation chamber 1 and the sheet material 10 are arranged in parallel with the end surfaces 5a and 5b. An antenna coil 11 is wound around the central portion 5C of the magnetic path structure 5 for one turn or more (in this embodiment, three turns). An impedance matching device 12 and a high frequency generation source 13 are connected to the antenna coil 11.

The plasma processing apparatus of this embodiment is intended to improve the airtightness of the sheet material 10 by coating the surface of the sheet material 10 with a DLC film (Diamond Like Carbon film). The vacuum chamber 3 is provided with a gas supply port 15 from which methane gas as a process gas is introduced into the plasma generation chamber 1. The vacuum chamber 3 is evacuated by a vacuum pump (for example, a turbo molecular pump) 16. The exhaust speed is 5,000 L / s, and the exhaust gas is exhausted to 10 ⁻³ Pa or less when no process gas is introduced.

  Methane gas whose flow rate is adjusted by a mass flow controller (not shown) is supplied from the gas supply port 15 to the plasma generation chamber 1. The vacuum pump 16 evacuates the vacuum chamber 3 so that the pressure in the plasma generation chamber 1 is maintained at 1 Pa. Then, high frequency power of 500 kHz and 5,000 W is applied from the high frequency generation source 13 to the antenna coil 11. Then, plasma is generated in the plasma generation chamber 1 and methane is decomposed to form radicals and ions to form a DLC film on the sheet material 10.

  In this way, by generating inductively coupled plasma using the magnetic path structure 5, a high-density uniform plasma can be created in a wide space, and a large-area workpiece can be processed at high speed. In this example, the frequency of the high-frequency generation source 13 is set to 500 kHz, but may be selected in the range of 100 kHz to 100 MHz.

  In the case of an inductively coupled plasma generating apparatus using only H discharge, only the magnetic flux component penetrating the end faces 5 a and 5 b vertically penetrates into the plasma generating chamber 1. Then, a rotating electric field is generated by the electromagnetic induction, and electrons rotate around the z axis (see FIG. 3) in the flat plasma generation chamber 1. At this time, since the electrostatic coupling force does not work between the electron and the antenna coil 11 or the magnetic path structure 5, the force for accelerating the electron in the z-axis direction does not work. Strictly speaking, there is a potential difference of several volts between the plasma potential and the wall potential, and there is a particle loss in which ions and electrons diffuse toward the wall due to the ambipolar diffusion phenomenon and die, but the pressure and high frequency power supply By appropriately selecting the frequency, the generation rate of ions and electrons generated by ionization in plasma can be made relatively high. As a result, the probability that electrons collide with the upper and lower wall surfaces of the plasma generation chamber 1 and disappear is remarkably reduced, so that plasma can be generated even in the flat plasma generation chamber 1. Therefore, since the distance between the end surfaces 5a and 5b of the magnetic path structure 5 can be shortened and a strong magnetic field can be penetrated into the plasma generation chamber 1, high-density plasma can be generated and the sheet material 10 can be processed at high speed. In addition, since the plasma potential is low, radicals attached to the inner wall of the plasma generation chamber 1 do not re-desorb and disturb the plasma composition. Therefore, it is possible to realize a film forming process that is stable for a long period of time without an increase in lot-to-lot variations. Further, if a substrate bias voltage is applied to the sheet material 10 by a power source (not shown), ions in the plasma can be accelerated and collide with the sheet material 10. As a result, the adhesion strength of the DLC film can be increased, but also in this case, since the plasma potential is low, there is an advantage that the set voltage of the substrate bias voltage can be easily controlled.

As the material of the magnetic path structure 5, a high magnetic permeability material having good high-frequency characteristics, that is, low hysteresis loss and low eddy current loss is used. In order to reduce the hysteresis loss, the energy required for reversing the magnetization direction of the magnetic domain of the crystal grains should be reduced, and in order to reduce the eddy current loss, the direction perpendicular to the direction in which the magnetic flux passes is reduced. What is necessary is just to make electrical resistance high. Specifically, it is preferable to use a soft ferrite that is a ferrimagnetic material having a high crystal resistance value, that is, a magnetic material having an insulating property and low hysteresis loss. More specifically, Mn—Zn ferrite ceramics and Ni—Zn ferrite ceramics which are spinel ferrite ceramics are preferably used. In order to further improve the high-frequency characteristics, for example, calcium oxide (CaO) and silicon oxide (SiO ₂ ) are added at the same time, and the specific resistance is increased by segregating these insulators at the grain boundaries, thereby reducing eddy current loss. Is preferably reduced.

  In order to reduce the hysteresis loss, it is effective to lower the reversal energy of the magnetic domain, so it is better to increase the crystal grain size. This is because when the crystal grain size is large, the distance between the domain walls becomes long, so that the magnetic moment can be continuously and gently reversed. However, since the eddy current loss increases when the crystal grain size is increased, the grain size is preferably 100 μm or less. However, when the crystal grain size is smaller than 1 μm, the state without a domain wall is more stable, and a single domain particle state having only one magnetic domain is obtained. In the single domain particle state, the magnetization loss cannot be reversed unless the magnetic moment is reversed, so that the hysteresis loss increases. In this case, the smaller the particle size, the lower the reversal energy, so the hysteresis loss can be reduced. On the other hand, when the particle diameter is extremely fine, such as 3 nm or less, superparamagnetism (super para) is obtained and the magnetism disappears, so that it cannot be used as a magnetic material. Therefore, when the crystal grain size is 1 μm or less, it is 3 nm to 1 μm, preferably 3 nm to 100 nm, and more preferably 3 nm to 10 nm. Then, both hysteresis loss and eddy current loss can be reduced.

  However, when the crystal grain size is reduced, the saturation magnetic flux density is reduced, and a high magnetic flux density cannot be passed through the magnetic path structure. Therefore, in order to minimize the eddy current loss and the hysteresis loss and to increase the saturation magnetic flux density and to pass the high magnetic flux density, the unit crystal is made into a whisker shape or a fiber shape having an aspect ratio of 5 or more. More preferably, the crystal is oriented so that the longitudinal direction of the crystal and the direction of the magnetic field are nearly parallel to each other.

Up to this point, we have described a method of making a magnetic path structure with a high saturation magnetic flux density and a low saturation loss, using a ferrimagnetic material with a low hysteresis loss. Preferably, a soft magnetic material may be used. As a material, iron, cobalt, nickel, molybdenum, boron, silicon, carbon, or the like can be used. In this case, the crystal is refined to 1 μm or less, and as described above, for example, calcium oxide (CaO) and silicon oxide (SiO ₂ ) are added simultaneously, and these insulators are segregated at the grain boundaries. The resistance can be increased, and as a result, the eddy current loss can be reduced. Moreover, since the specific resistance is increased by making the crystal amorphous, the eddy current loss can be reduced.

  In order to prevent the temperature of the magnetic path structure 5 from rising due to internal loss, as shown in FIG. 4, a flow path 8 is provided inside the magnetic path structure 5, and a cooling medium such as water or oil is provided therein. It is preferable to cool the magnetic path structure 5 through. When the magnetic path structure 5 is formed by sintering, the core can be arranged in advance in the powder, and the flow path can be formed by removing the core after compression molding.

  The magnetic path structure 5 can also be formed by stereolithography. The optical shaping method is a method of forming a structure having a desired shape by applying laser light to the powder to solidify the powder one by one and stacking the solidified layers. A three-dimensional model of a structure to be formed is input to a computer in advance, and the laser beam scans the powder along a circular slice shape that is sliced in the horizontal direction of the three-dimensional model. Therefore, if the flow path is incorporated in the three-dimensional model in advance, the flow path can be formed inside the magnetic path structure 5. If the stereolithography method is used, a three-dimensionally complicated flow path can be created, so that the cooling efficiency can be further increased.

  In order to efficiently transmit the power output from the high-frequency generation source 13 to the plasma, it is preferable to make the size of the gap (distance between the end faces 5a and 5b) of the magnetic path structure 5 as small as possible. This is because the magnetic flux density decreases in inverse proportion to the size of the air gap. Therefore, by using the end faces 5 a and 5 b of the magnetic path structure 5 as a part of the wall surface of the plasma generation chamber 1 in order to reduce the gap, the gap can be reduced. FIG. 5 shows an example. That is, in FIG. 5, both end surfaces 5 a and 5 b of the magnetic path structure 5 constitute an upper surface and a lower surface of the plasma generation chamber 1, respectively.

  FIG. 6 is a cross-sectional view showing a modified example of the end faces 5 a and 5 b of the magnetic path structure 5. Uniform plasma can be formed by making the end faces 5a and 5b opposite to each other flat, but depending on the type of gas and the purpose of the treatment, the spatial distribution of ion density or radical density is to be positively changed. There is. Such spatial control of the plasma density can be realized by forming the stepped portion 5c on the end surface 5a (and / or the end surface 5b) of the magnetic path structure 5, as shown in FIG. That is, since the magnetic flux density is high in the region where the air gap is small, the induced electric field strength is increased and the generated plasma density is increased. Conversely, the plasma density is low in the region where the gap is large. Thus, the distribution of the plasma density can be positively controlled by locally changing the size of the air gap. In the example shown in FIG. 6, the end face 5 a is formed in a stepped shape in order to change the size of the gap, but the shape of the end face 5 a is not limited to this. For example, a smooth curved surface shape or a plurality of needle-like protrusions having different lengths may be formed on the end surface 5a (and / or the end surface 5b). Furthermore, as shown in FIG. 7, a plurality of columnar projections 5d may be formed on the end surface 5a (and / or the end surface 5b), and plasma may be formed only on the portion of the projection 5d. Further, if a projection is formed on one or both of the upper inner surface and the lower inner surface of the plasma generation chamber 1 and plasma is formed only on the portion of the projection, the region where plasma is formed can be further localized.

  Furthermore, a plurality of pairs of end faces (plural gaps) may be provided in the magnetic path structure 5 and plasma may be formed between each pair of end faces. FIG. 8 is a plan view showing a configuration example of the plasma processing apparatus having such a configuration. In this example, the arms 5A and 5B of the magnetic path structure 5 are divided into three, and the magnetic flux generated by one antenna coil 11 is distributed to three parallel magnetic circuits. According to such a configuration, plasma can be formed between each pair of end faces.

  Further, when only the magnetic field generated by the antenna coil 11 is supplied to the plasma generation chamber 1, only H discharge occurs in the plasma generation chamber 1, so that it may be difficult to start discharge due to insufficient electrons. In such a case, it is preferable to provide an electron supply mechanism in order to easily start discharge. Specifically, an electron supply mechanism such as a hollow cathode electron source and a filament is provided in the vacuum chamber 3, and electrons are supplied into the plasma generation chamber 1 by the electron supply mechanism when a high-frequency current is supplied to the antenna coil 11.

  FIG. 9 is a schematic view showing an electron supply mechanism incorporated in the plasma processing apparatus. The electron supply mechanism 20 includes a tungsten filament 22 provided on the side wall of the plasma generation chamber 1 and a power source 23 connected to the tungsten filament 22. A current of about 20 A is supplied from the power source 23 to the tungsten filament 22, thereby supplying thermoelectrons into the plasma generation chamber 1.

FIG. 10 is a schematic diagram showing another configuration example of the electron supply mechanism. This configuration example is RF (Radio)
Frequency) is an electron supply mechanism using discharge. As shown in FIG. 10, the electron supply mechanism 20 includes a casing 24 made of a dielectric such as quartz glass, an antenna coil 25 disposed around the casing 24, and high frequency power to the antenna coil 25. A matching unit 26 and a high-frequency generation source 27 to be supplied, two electrodes 28 and 29 disposed inside the casing 24, and a power source 23 for applying a voltage to these electrodes 28 and 29 are provided. The antenna coil 25 is wound around the casing 24 about three times, and the antenna coil 25 is supplied with high frequency power of 13.56 MHz, for example.

  The casing 24 is provided on the side wall of the plasma generation chamber 1, and the inside of the casing 24 communicates with the plasma generation chamber 1. A small amount of Ar gas whose flow rate is adjusted by a mass flow controller (not shown) is introduced into the casing 24 through the inlet 24a. At this time, high frequency power is supplied to the antenna coil 25, thereby causing inductively coupled discharge in the casing 24. Then, by applying a voltage to the electrodes 28 and 29, electrons generated in the plasma are extracted. A small skimmer 29 a is provided on the electrode 29 on the plasma generation chamber side, and accelerated electrons are emitted to the plasma generation chamber 1 through the skimmer 29 a.

  FIG. 11 is a schematic diagram showing still another configuration example of the electron supply mechanism. As shown in FIG. 11, the two side walls of the casing 24 are constituted by dielectric plates 32 and 33. An electrode 29 is disposed on the dielectric plate 33 on the plasma generation chamber side, and an antenna coil 35 extending in a spiral shape is disposed on the back side of the dielectric plate 32. The casing 24 is provided with an inlet 24a, and a small amount of Ar gas is introduced into the casing 24 through the inlet 24a. Other configurations are almost the same as those of the electron supply mechanism shown in FIG. According to this configuration example, the casing 24 can be formed of metal, which is preferable because it can be easily manufactured.

  FIG. 12 is a schematic diagram showing still another configuration example of the electron supply mechanism. The electron supply mechanism 20 is a so-called hollow cathode electron source. As shown in FIG. 12, the side wall of the casing 24 on the plasma generation chamber side is constituted by a dielectric plate 33, and an electrode 29 is disposed on the dielectric plate 33. The casing 24 is made of metal, and a power source 23 is connected to the electrode 29 and the casing 24. Then, by applying a negative voltage to the casing 24 and setting the electrode 29 to the ground potential, it is possible to generate hollow cathode plasma and extract electrons. By using these electron supply mechanisms 20, the number of electrons generated by collision with gas molecules in the plasma generation chamber 1 increases, so that stable discharge can be caused.

  Although one embodiment of the present invention has been described so far, it is needless to say that the present invention is not limited to the above-described embodiment, and may be implemented in various forms within the scope of the technical idea.

1 is a perspective view showing an embodiment of an inductively coupled plasma processing apparatus according to the present invention. It is sectional drawing of the plasma processing apparatus shown in FIG. It is the III-III sectional view taken on the line of FIG. It is sectional drawing which shows the modification of a magnetic path structure. It is sectional drawing which shows the other modification of a magnetic path structure. It is sectional drawing which shows the other modification of a magnetic path structure. It is a perspective view which shows the modification of the end surface of a magnetic path structure. It is a top view which shows the other structural example of the plasma processing apparatus in one Embodiment of this invention. It is a schematic diagram which shows the electron supply mechanism integrated in the plasma processing apparatus which concerns on one Embodiment of this invention. It is a schematic diagram which shows the other structural example of an electron supply mechanism. It is a schematic diagram which shows the other structural example of an electron supply mechanism. It is a schematic diagram which shows the other structural example of an electron supply mechanism.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Plasma production chamber 2A, 2B Roller chamber 3 Vacuum chamber 5 Magnetic path structure 5a, 5b End surface 5c Step part 5d Protrusion 6 Feeding roller 7 Take-up roller 8 Flow path 10 Sheet material (processed object)
DESCRIPTION OF SYMBOLS 11 Antenna coil 12 Impedance matching device 13 High frequency generation source 15 Gas supply port 16 Vacuum pump 20 Electron supply mechanism 22 Tungsten filament 23 Power supply 24 Casing 24a Inlet 25, 35 Antenna coil 26 Matching device 27 High frequency generation source 28, 29 Electrode 29a Skimmer 32, 33 dielectric plate

Claims (6)

A plasma generation chamber in which an object to be processed is stored;
A magnetic path structure having at least one pair of end faces facing each other, and an antenna coil wound around the magnetic path structure;
A high frequency source for supplying a high frequency current to the antenna coil,
The plasma processing apparatus, wherein the plasma generation chamber is disposed between the end faces.   The plasma processing apparatus according to claim 1, wherein the object to be processed is arranged to be parallel to the end face.   The plasma processing apparatus according to claim 1, wherein the plasma density distribution in the plasma generation chamber is controlled by locally adjusting a distance between the end faces.   The plasma processing apparatus according to claim 1, wherein a height of the plasma generation chamber is 1 mm or more and 10 mm or less.   The plasma processing apparatus according to claim 1, wherein the end surface constitutes a wall surface of the plasma generation chamber.   The plasma processing apparatus according to claim 1, further comprising an electron supply mechanism for supplying electrons to the plasma generation chamber when a high frequency current is supplied to the antenna coil.

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