TW201332403A - Antenna unit for inductively coupled plasma and inductively coupled plasma processing apparatus - Google Patents

Abstract

The invention provides an antenna unit for inductively coupled plasma. Even when a high-frequency antenna which is disposed in a manner that over three ring-shaped antennas are concentrically disposed, the independent control performance of current of high-frequency ring-shaped antenna part is also provided. The antenna (13) of an antenna unit (50) is provided with at least three antenna parts (13a, 13b, 13c) which can sense the electric field and are concentrically disposed through providing high-frequency electricity in a processing chamber. Each antenna part is formed by coiling antenna lines (61, 62, 63, 64). Antenna lines of adjacent antenna parts among the antenna parts (13a, 13b, 13c) are coiled in a manner of mutual back rolling.

Description

Inductively coupled plasma antenna unit and inductively coupled plasma processing device

The present invention relates to an inductively coupled plasma antenna unit used for inductively coupled plasma processing of a substrate to be processed such as a glass substrate for manufacturing a flat panel display (FPD), and an inductively coupled plasma processing apparatus using the same.

A flat panel display (FPD) manufacturing process such as a liquid crystal display (LCD) includes a step of plasma treatment such as plasma etching or film formation on a glass substrate, and plasma is used for the plasma treatment. Various plasma processing apparatuses such as an etching apparatus or a plasma CVD film forming apparatus. In the past, a plasma-based plasma processing apparatus has been widely used in a plasma processing apparatus. However, in recent years, an inductively coupled plasma (ICP) processing apparatus having an advantage of obtaining high-density plasma with a high degree of vacuum has been attracting attention.

The inductively coupled plasma processing apparatus supplies a processing gas to the inside of the processing container by disposing the high frequency antenna on the upper side of the dielectric window (which constitutes the top wall of the processing container accommodating the substrate to be processed), and the high The frequency antenna supplies high frequency electric power, and inductively coupled plasma is generated in the processing container, and the inductively coupled plasma is used to apply a specific plasma treatment to the processed substrate. As the high-frequency antenna, a planar loop antenna having a planar specific pattern is often used.

Inductively coupled plasma processing apparatus using a planar loop antenna, although electricity is generated in a space directly below the planar antenna in the processing container Slurry, but at this time, because it corresponds to the electric field strength at each position directly below the antenna, and has a distribution of a high plasma density region and a low plasma density region, the pattern shape of the planar loop antenna becomes the plasma. An important factor in the density distribution, and by adjusting the density of the planar loop antenna, the induced electric field is homogenized to generate a uniform plasma.

Accordingly, a technique has been proposed in which antenna elements having two loop antenna portions having an inner portion and an outer portion are provided at intervals in the radial direction, and the impedances are adjusted to independently control the two. The current value of the loop antenna portion is controlled by the respective loop antenna portions to control the density distribution of the generated plasma due to diffusion, thereby controlling the density distribution of the inductively coupled plasma as a whole (Patent Document 1) .

However, when the substrate is a large substrate having a length of one side longer than 1 m, the plasma diffusion effect at the intermediate portion of the two loop antennas is insufficient if only the two loop antenna portions of the inner portion and the outer portion are used. Therefore, it is difficult to perform density distribution control.

Accordingly, there has been proposed a technique in which three or more loop antenna portions are arranged concentrically, and the current values are independently controlled, whereby uniform electric power can be formed even when the substrate size is a large substrate. Pulp (Patent Document 2).

Patent Document 1: Japanese Laid-Open Patent Publication No. 2007-311182

Patent Document 2: Japanese Laid-Open Patent Publication No. 2009-277859.

However, when three or more loop antenna portions are provided concentrically, magnetic field overlap occurs around the antenna, and the loop antenna portions interfere with each other, and the independent controllability of the induced electric field of each loop antenna portion is lowered.

The present invention has been made in view of the above circumstances, and an object of the invention is to provide a high-frequency antenna in which three or more loop antenna portions are concentrically arranged, and the independent controllability of the induced electric field of the loop antenna portion is still relatively high. An antenna unit for inductively coupled plasma and an inductively coupled plasma processing apparatus using the same.

In order to solve the above problems, a first aspect of the present invention provides an antenna unit for inductively coupled plasma having a planar antenna for forming an induced electric field for generating a plasma for a substrate in a processing chamber of a plasma processing apparatus. The inductively coupled plasma is processed; the antenna is concentrically provided with at least three antenna portions, and the antenna portion forms an induced electric field in the processing chamber by supplying high frequency electric power; the antenna portion is The antenna is wound in a spiral shape; and adjacent to each other of the antenna portions, the antennas are wound in a roll-like manner.

According to a second aspect of the present invention, there is provided an inductively coupled plasma processing apparatus comprising: a processing chamber for storing a rectangular substrate and applying a plasma treatment; and a mounting table for mounting a rectangular substrate in the processing chamber; and a processing gas a supply system for supplying a processing gas to the processing chamber; an exhaust system for exhausting the processing chamber; and a planar antenna disposed outside the processing chamber via a dielectric member, and supplied by High-frequency electric power to form an induced electric field, the inductive electric field is generated in the processing chamber to generate an inductively coupled plasma for plasma processing; and a high-frequency electric power supply mechanism for supplying high-frequency electric power to the antenna; Having at least three antenna portions disposed concentrically by forming an induced electric field in the processing chamber by supplying high-frequency electric power; the antenna portion is constituted by an antenna wound in a spiral shape; adjacent to the antenna portion The antennas are connected to each other in a roll-like manner.

In any of the above embodiments, preferably, the antenna portion is a multiple antenna composed of a plurality of antennas wound in a spiral shape, and the plurality of antennas are arranged to be shifted by a specific angle in a peripheral direction.

Moreover, preferably, the substrate is applied in a rectangular shape, and the antenna portion has a shape of a front edge corresponding to a rectangular substrate.

In this case, at least one of the antenna portions may be configured to be In the same plane, the plurality of antennas are wound in such a manner that the number of windings at the corners is larger than the number of windings at the central portion of the edges, and the whole is formed into a spiral shape. Further, it is preferable that the antenna portion is formed by winding the entire number of windings of the corner portion more than the number of windings at the center portion of the edge, and the outer contour line and the inner contour line are formed by the outer contour line and the inner contour line. The surrounding frontal region is formed with a curved portion in each antenna so as to be line-symmetric with respect to a center line passing through two opposite sides of the antenna portion.

At least one of the antenna portions may also have a plurality of regions corresponding to distinct portions of the substrate, and the plurality of regions are independently supplied with high frequency electric power.

Preferably, the method includes a power supply unit, and a plurality of antenna circuits including the antenna portions and the power supply units, and at least one impedance of the antenna circuits is adjusted to control current values of the antenna portions. An impedance control mechanism, wherein the power supply unit has a power supply path from a matcher connected to a high frequency power supply for supplying power to each antenna unit to the respective antennas. In this case, preferably, a variable capacitor provided in the power supply path can be used as the impedance control mechanism.

According to the present invention, since the antenna portion is constituted by an antenna that is wound in a spiral shape, the antennas are adjacent to each other in the antenna portion, and the antennas are wound such that the antenna portions are mutually reversed. In the case of the antenna portions, since the intermediate antenna portion is reversely wound with respect to the outer antenna portion and the inner antenna portion, an induced electric field in the opposite direction is generated in the intermediate antenna portion, whereby the outer side can be caused by the outer side. The induced electric field formed by the antenna portion, the inner antenna portion, and the intermediate antenna portion is separated to eliminate such interference, thereby improving the independent controllability. Thus, the plasma density distribution can be controlled corresponding to various processes.

1‧‧‧ body container

2‧‧‧Dielectric wall (dielectric component)

3‧‧‧Antenna room

4‧‧‧Processing room

13‧‧‧High frequency antenna

13a‧‧‧Outer antenna section

13b‧‧‧Internal antenna section

13c‧‧‧Intermediate antenna section

14‧‧‧matcher

15‧‧‧High frequency power supply

16a, 16b, 16c‧‧‧ power supply components

19,19a,19b,19c‧‧‧Power supply line

20‧‧‧Processing gas supply system

21a, 21c‧‧‧ Variable Capacitors

22a, 22b, 22c‧‧‧ terminals

23‧‧‧ mounting table

30‧‧‧Exhaust device

50‧‧‧Antenna unit

51‧‧‧Power Supply Department

61,62,63,64,71,72,73,74,81,82,83,84‧‧‧Antenna

67,77,87‧‧‧ frontal area

68,78,88‧‧‧ crank (bending)

91a‧‧‧Outer antenna circuit

91b‧‧‧Inside antenna circuit

91c‧‧‧Intermediate antenna circuit

100‧‧‧Control Department

101‧‧‧User interface

102‧‧‧Memory Department

G‧‧‧Substrate

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view showing an inductively coupled plasma processing apparatus according to an embodiment of the present invention.

Fig. 2 is a plan view showing an example of an antenna unit for inductively coupled plasma used in the inductively coupled plasma processing apparatus of Fig. 1.

3 is a plan view showing the outer contour line, the inner contour line, and the forehead area surrounded by the high frequency antenna of FIG. 2, and the curved portion of the antenna.

4 is a view showing a power supply circuit of a high frequency antenna used in the inductively coupled plasma processing apparatus of FIG. 1.

Figure 5 is a diagram for comparing and explaining the state of the magnetic field and the induced magnetic field and the plasma when the current flows through the conventional three-ring antenna (a), and the magnetic field and the induced magnetic field when the current flows through the antenna of the embodiment. Schematic diagram of the state (b) of the plasma.

Fig. 6 is a plan view showing another embodiment of the radio-frequency antenna.

Fig. 7 is a plan view showing a first portion of an antenna portion used in the high frequency antenna of Fig. 6.

Fig. 8 is a plan view showing a second portion of the antenna portion used in the radio-frequency antenna of Fig. 6.

Fig. 9 is a view showing still another example of the antenna portion.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. 1 is a cross-sectional view showing an inductively coupled plasma processing apparatus according to an embodiment of the present invention, and FIG. 2 is a plan view showing an antenna unit used in the inductively coupled plasma processing apparatus. This apparatus is used for, for example, etching of a metal film, an ITO film, an oxide film, or the like, or ashing treatment of a resist film when a thin film transistor is formed on a glass substrate for FPD. Examples of the FPD include a liquid crystal display, an electroluminescence (EL) display, a plasma display panel (PDP), and the like.

This plasma processing apparatus has a rectangular tubular hermetic container 1 made of a conductive material (for example, aluminum whose inner wall surface is anodized). The body container 1 is disassemblably assembled, and the ground line 1a is grounded. The main body container 1 is partitioned into the antenna chamber 3 and the processing chamber 4 up and down by the dielectric body wall 2. Thus, the dielectric body wall 2 constitutes the top wall of the processing chamber 4. The dielectric body wall 2 is made of ceramic such as Al ₂ O ₃ , quartz or the like.

A shower frame 11 for supplying a processing gas is embedded in a lower portion of the dielectric body wall 2. The shower frame 11 is formed in a cross shape and is configured to support the dielectric body wall 2 from below. Further, the shower frame body 11 that supports the dielectric body wall 2 is suspended from the top of the main body container 1 by a plurality of hangers (not shown).

The shower frame 11 is made of a conductive material, preferably a metal such as aluminum which is anodized on the inner or outer surface thereof, so that no contaminants are generated. The shower housing 11 is formed with a gas passage 12 extending horizontally, and the gas passage 12 is connected to a plurality of gas discharge holes 12a extending downward. On the other hand, the upper center of the dielectric body wall 2 is provided with a gas supply pipe 20a in communication with the gas flow path 12. The gas supply pipe 20a is inserted from the top of the main body container 1 to the outside thereof, and is connected to the process gas supply system 20 including the process gas supply source, the valve system, and the like. Then, in the plasma processing, the processing gas supplied from the processing gas supply system 20 is supplied into the shower frame 11 via the gas supply pipe 20a, and is ejected from the lower gas ejection hole 12a to the processing chamber. 4 inside.

A support frame 5 projecting inwardly is disposed between the side wall 3a of the antenna chamber 3 in the main body container 1 and the side wall 4a of the processing chamber 4, and the dielectric wall 2 is placed on the support frame 5.

An antenna unit 50 including a high frequency (RF) antenna 13 is disposed in the antenna chamber 3. The high frequency antenna 13 is connected to the high frequency power source 15 via the matching unit 14. Further, the radio-frequency antenna 13 is separated from the dielectric body wall 2 by a spacer 17 made of an insulating member. Then, by coming from the high frequency power supply 15 The high frequency antenna 13 is supplied with high frequency electric power having a frequency of, for example, 13.56 MHz, and an induced electric field is formed in the processing chamber 4, and the processing gas supplied from the shower frame 11 is plasmad by the induced electric field. Further, the antenna unit 50 will be described later.

In the lower portion of the processing chamber 4, the dielectric wall 2 is placed therein, and a mounting table 23 for mounting a rectangular FPD glass substrate (hereinafter simply referred to as a substrate) G is disposed opposite to the high-frequency antenna 13 . The mounting table 23 is made of a conductive material such as aluminum whose surface is anodized. The substrate G placed on the mounting table 23 is sucked and held by an electrostatic chuck (not shown).

The mounting table 23 is housed in the insulator frame 24 and is further supported by the hollow pillars 25. The support post 25 is inserted through the bottom of the main body container 1 while maintaining the airtight state, and is supported by an elevating mechanism (not shown) disposed outside the main body container 1. When the substrate G is carried in and out, the elevating mechanism is used. The mounting table 23 is driven in the vertical direction. Further, between the insulator frame 24 in which the mounting table 23 is housed and the bottom portion of the main body container 1, a bellows 26 that hermetically surrounds the column 25 is provided, whereby the vertical movement of the mounting table 23 can be ensured. The airtightness in the container 4 is treated. Further, the side wall 4a of the processing chamber 4 is provided with a gate valve 27 for carrying out the carry-in/out port 27a of the substrate G and opening and closing the same.

The mounting table 23 is connected to the high-frequency power source 29 via a power supply line 25a provided in the hollow pillar 25 and through the matching unit 28. The high-frequency power source 29 applies a bias high-frequency electric power to the mounting table 23 during the plasma processing, for example, a high-frequency electric power having a frequency of 6 MHz. By the high frequency electric power of the bias voltage, ions generated in the plasma in the processing chamber 4 are efficiently attracted to the substrate G.

Further, a temperature control mechanism including a heating means such as a ceramic heater for controlling the temperature of the substrate G, a refrigerant flow path, and the like is provided in the mounting table 23, and a temperature sensor (none of which is shown). Relative to such institutions The piping or wiring of the components is led out of the body container 1 through the hollow pillars 25.

The bottom of the processing chamber 4 is connected to an exhaust device 30 including a vacuum pump or the like through an exhaust pipe 31. When the processing chamber 4 is exhausted by the exhaust device 30, the inside of the processing chamber 4 is set and maintained in a specific vacuum atmosphere (for example, 1.33 Pa) in the plasma processing.

A cooling space (not shown) is formed on the inner surface side of the substrate G placed on the mounting table 23, and a He gas flow path 41 for supplying He gas as a heat conduction gas as a constant pressure is provided. By supplying the heat conduction gas to the inner surface side of the substrate G in this manner, temperature rise or temperature change of the substrate G can be avoided under vacuum.

Each component of the plasma processing apparatus is controlled to be connected to a control unit 100 constituted by a microprocessor (computer). Further, the control unit 100 is connected to a user interface 101 including a keyboard for inputting an operation such as command input for managing a plasma processing device, or a display for visually displaying an operation state of the plasma processing device. Further, the control unit 100 is connected to a storage unit 102 that stores a control program for realizing various processes executed by the plasma processing device under the control of the control unit 100, or corresponds to processing conditions. Each component of the plasma processing apparatus executes a processing program (ie, a processing recipe). The processing recipe is a memory medium that is memorized in the memory unit 102. The memory medium can be a hard disk or a semiconductor memory built in a computer, or a removable person such as a CDROM, a DVD, or a flash memory. Further, the recipe can be appropriately transferred from other devices through, for example, a dedicated return line. Then, if necessary, an arbitrary processing recipe is called from the memory unit 102 by an instruction from the user interface 101, and the control unit 100 is executed, whereby the plasma processing apparatus performs the control under the control of the control unit 100. I want to deal with it.

Next, the antenna unit 50 described above will be described in detail.

The antenna unit 50 has a high frequency antenna 13 as described above, and another Further, the power supply unit 51 that supplies power to the high frequency antenna 13 via the high frequency electric power of the matching unit 14 is provided.

As shown in FIG. 2, the high-frequency antennas 13 are arranged concentrically with a loop antenna portion (outer antenna portion 13a) disposed at the outer portion, a loop antenna (inner antenna portion 13b) disposed at the inner portion, and A three-ring antenna formed of the loop antenna portion (the intermediate antenna portion 13c) at the intermediate portion of the intermediate portion. Each of the outer antenna portion 13a, the inner antenna portion 13b, and the intermediate antenna portion 13c has a rectangular planar shape, and the arrangement region of the antenna disposed opposite to the substrate has a marginal shape.

The outer antenna portion 13a, the inner antenna portion 13b, and the intermediate antenna portion 13c constitute a multiple (quadruple) antenna, which is wound around four antennas and has a spiral shape as a whole, and the winding direction of the antenna is the outer antenna portion 13a and the inner antenna. The portion 13b is the same, and the intermediate antenna portion 13c is opposite to the above. That is, the winding direction of the antenna is configured to be reversed between adjacent antenna portions.

The outer antenna portion 13a has four antennas 61, 62, 63, 64, and the positions of the antennas 61, 62, 63, 64 are respectively wound by 90°, and the arrangement area of the antenna is a marginal shape. In the corner where the plasma tends to weaken, the number of rolls is much larger than the number of rolls in the center of the edge. In the illustrated example, the number of turns in the corner is 3, and the number of turns in the center of the edge is 2. Further, as shown in FIG. 3, in order to make the antenna arrangement region (frontal edge region 67) displayed by the oblique line around the outer contour line 65 and the inner contour line 66 of the outer antenna portion 13a, the rectangular substrate G is aligned with respect to the rectangular substrate G. A crank portion (curved portion) 68 is formed in each antenna so that the center line of the two sides of the outer antenna 13a is line-symmetric (mirror-symmetric). Since the plasma is generated corresponding to the arrangement area of the antenna, the plasma generated by the outer antenna portion 13a can be made to face the substrate G by causing the front edge region 67 to face the substrate G as described above.

The inner antenna portion 13b has four antennas 71, 72, 73, 74, and the positions of the antennas 71, 72, 73, 74 are respectively shifted by 90°, and are wound into the outer side. The antennas of the antenna portion 13a are in the same direction, and the arrangement region of the antenna has a slightly marginal shape, which is such that the number of windings at the corner portion where the plasma tends to be weaker is much larger than the number of windings at the center portion of the edge. In the illustrated example, the number of turns in the corner is 3, and the number of turns in the center of the edge is 2. Further, as shown in FIG. 3, in order to make the forehead region 77 displayed by the oblique line surrounded by the outer contour line 75 and the inner contour line 76 of the inner antenna portion 13b, the rectangular substrate G is aligned with respect to the two sides of the penetrating direction. The center line is line-symmetrical (mirror-symmetric), and a crank portion (curved portion) 78 is formed in each antenna. Thereby, the plasma generated by the inner antenna portion 13b can be made to face the substrate G.

The intermediate antenna portion 13c has four antennas 81, 82, 83, 84, and the positions of the antennas 81, 82, 83, and 84 are shifted by 90 degrees, respectively, and are wound into antennas with the outer antenna portion 13a and the inner antenna portion 13b. In the opposite direction, the arrangement area of the antenna is slightly marginal, which is such that the number of turns in the corner where the plasma tends to weaken is much larger than the number of turns in the central portion of the edge. In the illustrated example, the number of turns in the corner is 2, and the number of turns in the center of the edge is 1. Further, as shown in FIG. 3, in order to make the front edge region 87 indicated by the oblique line surrounded by the outer contour line 85 and the inner contour line 86 of the intermediate antenna portion 13c, the rectangular substrate G is aligned with respect to the two sides of the penetrating direction. The center line is line-symmetric (mirror-symmetric), and a crank portion (curved portion) 88 is formed in each antenna. Thereby, the plasma generated by the intermediate antenna portion 13c can be made to face the substrate G.

The antenna room 3 is provided with four first power supply units 16a that supply power to the outer antenna unit 13a, four second power supply units 16b that supply power to the inner antenna unit 13b, and four third power supply units that supply power to the intermediate antenna unit 13c. 16c (only one is shown in Fig. 1), the lower end of each of the first power supply units 16a is connected to the terminal 22a of the outer antenna portion 13a, and the lower end of each of the second power supply units 16b is connected to the terminal 22b of the inner antenna portion 13b. The lower end of each of the third power supply units 16c is connected to the terminal 22c of the intermediate antenna portion 13c. The first power supply unit 16a, the second power supply unit 16b, and the third power supply unit 16c are connected in parallel to the high frequency power supply 15 via the matching unit 14. high frequency The power supply 15 and the matching unit 14 are connected to the power supply line 19, and the power supply line 19 is branched into the power supply lines 19a, 19b and 19c on the downstream side of the matching unit 14, and the power supply line 19a is connected to the four first power supply units 16a, and the power supply line. 19b is connected to the four second power supply units 16b, and the power supply line 19c is connected to the four third power supply units 16c.

The power supply lines 19, 19a, 19b, and 19c, the power supply units 16a, 16b, and 16c, and the terminals 22a, 22b, and 22c constitute the power supply unit 51 of the antenna unit 50.

The power supply line 19a is provided with a variable capacitor 21a, the power supply line 19c is provided with a variable capacitor 21c, and the power supply line 19b is not provided with a variable capacitor. Then, the outer antenna circuit is constituted by the variable capacitor 21a and the outer antenna portion 13a, and the intermediate antenna circuit is constituted by the variable capacitor 21c and the intermediate antenna portion 13c. On the other hand, the inner antenna circuit is composed only of the inner antenna portion 13b.

As will be described later, the impedance of the outer antenna circuit is controlled by adjusting the capacitance of the variable capacitor 21a, and the impedance of the intermediate antenna circuit is controlled by adjusting the capacitance of the variable capacitor 21c. With these controls, the flow can be adjusted. The magnitude relationship of the currents of the outer antenna circuit, the inner antenna circuit, and the intermediate antenna circuit. The variable capacitors 21a and 21c function as a current control unit of the outer antenna circuit and the intermediate antenna circuit.

The impedance control of the radio-frequency antenna 13 will be described with reference to FIG. 4. 4 is a view showing a power supply circuit of the high frequency antenna 13. As shown in the figure, the high-frequency electric power from the high-frequency power source 15 is supplied to the outer antenna circuit 91a, the inner antenna circuit 91b, and the intermediate antenna circuit 91c via the matching unit 14. Here, since the outer antenna circuit 91a is constituted by the outer antenna portion 13a and the variable capacitor 21a, and the intermediate antenna circuit 91c is constituted by the intermediate antenna circuit 13c and the variable capacitor 21c, the impedance Zout of the outer antenna circuit 91a can be By adjusting the orientation of the variable capacitor 21a to change its capacitance, the impedance Zmiddle of the intermediate antenna circuit 91c can be changed by adjusting the orientation of the variable capacitor 21c to change its capacitance. change. On the other hand, the inner antenna circuit 91b is composed only of the inner antenna portion 13b, and its impedance Zin is fixed. At this time, the current Iout of the outer antenna circuit 91a can be changed in accordance with the change in the impedance Zout, and the current Imiddle of the intermediate antenna circuit 91c can be changed in accordance with the change in the change of the impedance Zmiddle. Then, the current Iinc of the inner antenna circuit 91b changes in accordance with the ratio of Zout to Zmiddle and Zin. Then, by changing the capacitance of the variable capacitors 21a, 21c to change Zout and Zmiddle, the current Iout of the outer antenna circuit 91a, the current Iin of the inner antenna circuit 91b, and the current Imiddle of the intermediate antenna circuit 91c can be freely changed. Then, the plasma density distribution can be controlled by controlling the current flowing through the outer antenna portion 13a, the current flowing through the inner antenna portion 13b, and the current flowing through the intermediate antenna portion 13c.

Next, a description will be given of a processing operation when the substrate G is subjected to a plasma treatment (for example, plasma etching treatment) using the inductively coupled plasma processing apparatus configured as described above.

First, when the gate valve 27 is opened, the substrate G is carried into the processing chamber 4 from the carry-out port 27a by a transport mechanism (not shown), and placed on the mounting surface of the mounting table 23, and then electrostatically clamped ( The substrate G is fixed to the mounting table 23 (not shown). Next, the process gas supplied from the process gas supply system 20 to the process chamber 4 is ejected from the gas discharge hole 12a of the shower frame 11 into the process chamber 4, and is exhausted through the exhaust pipe by the exhaust device 30. 31, the inside of the processing chamber 4 is evacuated, thereby maintaining the processing chamber at a pressure atmosphere of, for example, about 0.66 to 26.6 Pa.

In addition, in this case, the cooling space on the inner surface side of the substrate G is supplied with He gas as a heat conduction gas through the He gas flow path 41 in order to avoid temperature rise or temperature change of the substrate G.

Next, a high frequency of, for example, 13.56 MHz is applied to the high frequency antenna 13 from the high frequency power source 15 to form a uniform induced electric field in the processing chamber 4 through the dielectric body wall 2. With the induced electric field thus formed, everywhere The process gas is plasmad in the chamber 4 to produce a high density inductively coupled plasma. The substrate G is then subjected to a plasma treatment, such as a plasma etching process, by the plasma.

In this case, the high-frequency antenna 13 is disposed such that the loop antenna portion (outer antenna portion 13a) disposed at the outer portion and the loop antenna portion disposed at the inner portion (inside) are disposed concentrically with each other as described above. The antenna portion 13b) and the three-loop antenna formed by the loop antenna portion (intermediate antenna portion 13c) disposed at the intermediate portion of the antenna portion 13b) are such that the size of the glass substrate G is larger than one large substrate of one side. It is still not easy to cause plasma unevenness due to a decrease in plasma density between the antenna portions.

Further, since the high frequency antenna 13 is connected to the outer antenna portion 13a with the variable capacitor 21a, the impedance of the outer antenna circuit 91a can be adjusted, and the variable capacitor 21c is connected to the intermediate antenna portion 13c, and the impedance of the intermediate antenna circuit 91c can be adjusted. Therefore, the current Iout of the outer antenna circuit 91a, the current Iin of the inner antenna circuit 91b, and the current Imiddle of the intermediate antenna circuit 91c can be freely changed. In other words, by adjusting the orientation of the variable capacitors 21a and 21c, it is possible to control the current flowing through the outer antenna portion 13a, the current flowing through the inner antenna portion 13b, and the current flowing through the intermediate antenna portion 13c. The inductively coupled plasma is such that the plasma is generated in a space directly below the high frequency antenna 13, but since the plasma density at each position corresponds to the electric field intensity at each position, the flow is controlled to the outside by such control. The plasma density distribution can be controlled by controlling the electric field intensity distribution by the current of the antenna portion 13a, the current flowing through the inner antenna portion 13b, and the current flowing through the intermediate antenna portion 13c.

Depending on the process, plasmas that do not have a uniform density distribution are best suited for the process. Therefore, by controlling the most appropriate plasma density distribution corresponding to the process, and setting the orientation of the variable capacitors 21a, 21c at which the plasma density distribution can be obtained in advance in the memory unit 102, the control unit 100 can be used. Select the most appropriate variable capacitors 21a, 21c for each process The plasma is processed in the orientation.

However, in the past, in the above-described three-ring antenna, the three antenna portions are wound in the same direction in the same direction. Therefore, as shown in FIG. 5(a), it is found that the magnetic field generated by the current flowing through the antenna is in the same direction in each antenna portion, and interference occurs between the three antenna portions due to the overlapping of the magnetic fields. As a result, the independent controllability of the induced electric field at the antenna portions is deteriorated. As a result, the controllability of the plasma density distribution deteriorates.

On the other hand, in the present embodiment, as shown in FIG. 5(b), the winding direction of the antenna is the same as that of the outer antenna portion 13a and the inner antenna portion 13b, and the intermediate antenna portion 13c is opposite to the above. That is, the winding direction of the antenna is configured such that adjacent antenna portions are opposite to each other. By causing the intermediate antenna portion 13c to be wound in the opposite direction as described above, the intermediate antenna portion 13c generates an induced electric field in the opposite direction, whereby the outer antenna portion 13a, the inner antenna portion 13b, and the intermediate antenna can be made. The induced electric field formed by the portion 13c is separated to eliminate such interference, thereby improving the independent controllability. Thus, the plasma density distribution can be controlled corresponding to various processes.

Further, in Fig. 5, the × of the antenna indicates that the electric field is perpendicular to the plane of the paper and faces from the surface toward the inner surface, and the lanthanum indicates that the electric field is perpendicular to the plane of the paper and faces from the inner surface toward the surface.

Further, since the overall shape of the radio-frequency antenna 13 is a rectangle corresponding to the substrate G, the plasma can be supplied to the entire rectangular substrate G. Further, since the antenna portions are slightly edge-shaped and the number of antenna coils at the corner portions where the plasma tends to be weak is increased, a plasma density distribution having high uniformity can be obtained. However, if the number of antenna coils in the corner portion is large in each antenna portion, as shown in Patent Documents 1 and 2, the antenna will be compared with the center portion of the edge at the outermost circumference and the innermost circumference. Exceeding the outer side and the inner side, the outer contour line and the inner contour line are inclined, so that the plasma generating area surrounded by the outer surface of the rectangular substrate G becomes inclined at a specific angle with respect to the center of the rectangular substrate G, and there is a relative Uniformity of the plasma on the substrate G Insufficient sexuality.

On the other hand, in the present embodiment, crank portions (curved portions) 68, 78, and 88 are formed on the antennas of the outer antenna portion 13a, the inner antenna portion 13b, and the intermediate antenna portion 13c, respectively, to eliminate the volume due to the corner portion. The number is increased to exceed the outer side and the inner side, so that the front edge regions 67, 77, 87 of the respective antenna portions can form a plasma for the state of the rectangular substrate G with respect to the rectangular substrate G, and can be more uniform Plasma treatment.

Further, the present invention is not limited to the above embodiment, and various modifications can be made. For example, in the above-described embodiment, although three antenna portions are provided, the present invention is not limited thereto, and the coiling direction of the antenna may be opposite to the adjacent antenna portions, and may correspond to the size of the substrate. Four or more antenna sections are provided.

Further, in the above-described embodiment, the antenna portions are quadruple antennas in which four antennas are respectively wound by 90° and are wound in a spiral shape. However, the number of antennas is not limited to four, but may be Any number of multiple antennas, and the angle of misalignment is not limited to 90 degrees. Further, in each of the antenna portions, a crank portion (curved portion) is formed for the front edge region to face the rectangular substrate, but a multiple antenna having a crank portion and a front edge region facing the rectangular substrate may be used. .

Further, in the above-described embodiment, the antenna portions are configured to be annular, and the high-frequency electric power is integrally supplied. However, the antenna portion may have a plurality of regions corresponding to the different portions of the substrate, respectively, independently. The high frequency electric power is supplied to the plurality of regions. Thereby, finer plasma distribution control can be performed. For example, it is configured to have a rectangular plane corresponding to a rectangular substrate, and has a first portion and a second portion which are formed by winding a plurality of antennas in a spiral shape, and the first portion is provided as a plurality of corner portions in which a plurality of antennas form a rectangular plane. And combining four corners at a position different from the rectangular plane, the second part is configured such that the complex antenna system forms a central portion of the four sides of the rectangular plane, and combines four at positions different from the rectangular plane At the center of the side, you can The high frequency electric power is supplied to the first portion and the second portion independently.

The specific structure will be described with reference to Figs. For example, the outer antenna portion 13a is formed as shown in FIG. 6, and the portion facing the dielectric wall 2 (which forms an induced electric field contributing to plasma generation) integrally constitutes a rectangle corresponding to the rectangular substrate G. The edge portion has a plane and has a first portion 113a and a second portion 113b which are formed by winding a plurality of antennas in a spiral shape. The antenna of the first portion 113a is provided to form four corners of a rectangular plane, and four corners are combined at a position different from the rectangular plane. Further, the antenna of the second portion 113b is provided so as to form a central portion of the four sides of the rectangular plane, and the central portions of the four sides are joined at positions different from the rectangular plane. The power supply for the first portion 113a is transmitted through the four terminals 122a and the power supply line 169, and the power supply for the second portion 113b is transmitted through the four terminals 122b and the power supply line 179, and the terminals 122a and 122b are independently Supply high frequency electric power.

As shown in FIG. 7, the first portion 113a constitutes a quadruple antenna in which the positions of the four antennas 161, 162, 163, and 164 are respectively shifted by 90°, and forms four corners facing the rectangular plane of the dielectric body wall 2. The portions of the portions are the flat portions 161a, 162a, 163a, and 164a, and the portions between the flat portions 161a, 162a, 163a, and 164a are retracted to the position where they are different from the rectangular plane. The three-dimensional portions 161b, 162b, 163b, and 164b in a state where the plasma is generated are not supported. As shown in FIG. 8, the second portion 113b also constitutes a quadruple antenna in which the positions of the four antennas 171, 172, 173, and 174 are respectively shifted by 90, and four rectangular planes facing the dielectric wall 2 are formed. The central portion of the side is formed as flat portions 171a, 172a, 173a, and 174a, and the portion between the flat portions 171a, 172a, 173a, and 174a is formed at a position different from the rectangular plane. The three-dimensional portions 171b, 172b, 173b, and 174b in a state where the position where the plasma is generated are not retracted to the upper side.

With the above-described configuration, a simple multi-antenna structure in which four antennas similar to the above-described embodiment are wound in a certain direction can be obtained, and plasma distribution control in which the corner portion and the center portion of the edge are independent can be realized. Further, in the above-described configuration, the induced electric field in the opposite direction can be formed by changing the winding direction of the antenna.

Further, in the above-described embodiment, each antenna portion is configured by a plurality of antennas in which a plurality of antennas are wound. However, as shown in FIG. 9, one antenna 181 may be wound in a spiral shape.

Furthermore, the types of the antenna portions may not necessarily be the same. For example, the outer antenna portion may be configured as described above with reference to FIGS. 6 to 8, and the other may be a normal multiple antenna, or a crank portion may be provided in a part of the antenna portion, or may be mixed. Multiple antennas and one antenna for winding.

Further, in the above-described embodiment, the high-frequency electric power is supplied to each antenna portion from one high-frequency power source, but a high-frequency power source may be provided in each antenna portion.

Further, in the above-described embodiment, a variable capacitor is provided for the outer antenna circuit and the intermediate antenna circuit for controlling the current of each antenna portion, and the impedance adjustment circuit for the variable capacitor is not provided for the inner antenna circuit. However, if any of the outer antenna circuit, the inner antenna circuit, and the intermediate antenna circuit is provided with a variable capacitor, current control equivalent to that of the above-described embodiment can be performed, and even if it is not the same as the above-described embodiment The current is controlled, and the variable capacitor can also be set corresponding to the required current controllability. For example, a variable capacitor may be provided in all of the antenna circuits, or a variable capacitor may be provided in only one of the antenna circuits. Further, although a variable capacitor is used to adjust the impedance, it may be another impedance adjustment mechanism such as a variable coil.

Furthermore, in the above embodiment, the top portion of the processing chamber is formed by the dielectric body wall, and the antenna system is disposed on the top of the processing chamber. Although the structure of the upper surface of the dielectric body wall is demonstrated, if it is possible to isolate the antenna and the plasma generation region by the dielectric body wall, the antenna system may be disposed in the processing chamber.

Further, in the above embodiment, the present invention is applied to an etching apparatus, but it can also be applied to other plasma processing apparatuses such as CVD film formation. Further, although a rectangular substrate using FPD is used as an example of a substrate, it can also be applied to the case of processing other rectangular substrates such as solar cells, and is not limited to a rectangular shape, but can be applied to, for example, a semiconductor wafer. A circular substrate.

13‧‧‧High frequency antenna

13a‧‧‧Outer antenna section

13b‧‧‧Internal antenna section

13c‧‧‧Intermediate antenna section

20a‧‧‧ gas supply pipe

22a, 22b, 22c‧‧‧ terminals

61,62,63,64,71,72,73,74,81,82,83,84‧‧‧Antenna

68,78,88‧‧‧ crank (bending)

G‧‧‧Substrate

Claims (16)

An inductively coupled plasma antenna unit having a planar antenna for forming an induced electric field for generating an inductively coupled plasma for plasma processing of a substrate in a processing chamber of a plasma processing apparatus; The antenna is concentrically provided with at least three antenna portions, wherein the antenna portion forms an induced electric field in the processing chamber by supplying high-frequency electric power; the antenna portion is formed by an antenna that is wound into a spiral shape; Adjacent to each other in the antenna portion, the antennas are wound in a roll-like manner. The antenna unit for inductively coupled plasma according to claim 1, wherein the antenna portion is a multiple antenna composed of a plurality of antennas wound in a spiral shape, and the plurality of antennas are arranged to be shifted by a specific angle in a peripheral direction. The antenna unit for an inductively coupled plasma according to claim 2, wherein the substrate has a rectangular shape, and the antenna portion has a frontal shape corresponding to a rectangular substrate. The antenna unit for inductively coupled plasma according to claim 3, wherein at least one of the antenna portions is configured to be in the same plane, and the number of turns in the corner portion is larger than the number of turns in the central portion of the edge portion. In this way, the plurality of antennas are wound and the whole is spiraled. The antenna unit for an inductively coupled plasma according to the fourth aspect of the invention, wherein the number of the corners is larger than the number of turns in the central portion of the edge, and the antenna portion is formed in a spiral shape as a whole. The forehead region surrounded by the outer contour line and the inner contour line is formed with a curved portion in each antenna so as to be line-symmetric with respect to a center line passing through two opposite sides of the antenna portion. The antenna unit for inductively coupled plasma according to any one of claims 1 to 5, wherein at least one of the antenna portions has a corresponding substrate The complex regions of the distinct portions, and the high frequency electrical power is independently supplied to the plurality of regions. The inductively coupled plasma antenna unit according to any one of claims 1 to 6, further comprising: a power supply unit; and a plurality of antenna circuits including the antenna portions and the power supply units; An impedance control mechanism for controlling a current value of each antenna portion by at least one impedance of the antenna circuit, wherein the power supply portion has a matching device connected to a high frequency power supply for supplying power to each antenna portion to the antennas Power path. The antenna unit for inductively coupled plasma according to claim 7, wherein the impedance control mechanism has a variable capacitor disposed in the power supply path. An inductively coupled plasma processing apparatus comprising: a processing chamber for storing a rectangular substrate and applying a plasma treatment; a mounting table for placing a rectangular substrate in the processing chamber; and a processing gas supply system for the processing chamber Supplying a processing gas; an exhaust system for exhausting the processing chamber; a planar antenna disposed outside the processing chamber via a dielectric component, and forming an induced electric field by supplying high-frequency electric power, The induction electric field is generated in the processing chamber to generate an inductively coupled plasma for plasma processing the substrate; and a high frequency electric power supply mechanism for supplying high frequency electric power to the antenna; the antenna is provided with high frequency electric power by supplying And forming at least three antenna portions concentrically arranged in the processing chamber in the processing chamber; the antenna portion is formed by an antenna wound in a spiral shape; and adjacent ones of the antenna portions are opposite to each other Winding like a roll. The inductively coupled plasma processing apparatus according to claim 9, wherein the antenna portion is a multiple antenna composed of a plurality of antennas wound in a spiral shape, and the plurality of antennas are arranged to be shifted by a specific angle in a peripheral direction. For example, inductively coupled plasma processing apparatus of claim 10, wherein The substrate has a rectangular shape, and the antenna portion has a frontal shape corresponding to a rectangular substrate. The inductively coupled plasma processing apparatus according to claim 11, wherein at least one of the antenna portions is configured to be in the same plane, and the number of corners is larger than the number of windings at the central portion of the edge. The plurality of antennas are wound to form a spiral shape as a whole. The inductively coupled plasma processing apparatus according to claim 12, wherein the number of the corners is larger than the number of turns of the central portion of the edge, and the antenna portion is formed in a spiral shape as a whole. The forehead region surrounded by the outer contour line and the inner contour line is formed with a curved portion in each antenna so as to be line-symmetric with respect to a center line passing through two opposite sides of the antenna portion. The inductively coupled plasma processing apparatus according to any one of claims 9 to 13, wherein at least one of the antenna portions has a plurality of regions corresponding to different portions of the substrate, and the plurality of regions are independent The ground supplies high frequency electric power. The inductively coupled plasma processing apparatus according to any one of claims 9 to 14, wherein the high frequency electric power supply mechanism has: a high frequency power supply for supplying power to each antenna unit; and is connected to the high frequency power supply a matching device for impedance matching; a power supply portion having a power supply path from the matching device to the antennas; a plurality of antenna circuits including the antenna portions and the power supply portions; and adjusting at least one impedance of the antenna circuit, and further An impedance control mechanism that controls the current value of each antenna portion. The inductively coupled plasma processing apparatus of claim 15, wherein the impedance control mechanism has a variable capacitor disposed in the power supply path.