JP7503422B2 - Plasma processing apparatus and method for processing a substrate - Patents.com - Google Patents

Description

An exemplary embodiment of the present disclosure relates to a plasma processing apparatus and a method for processing a substrate.

In the manufacture of electronic devices, plasma processing is performed on a substrate. The plasma processing requires uniformity in the radial direction of the substrate. In order to improve the uniformity of the plasma processing in the radial direction of the substrate, a plasma processing apparatus equipped with an electromagnet is sometimes used. A plasma processing apparatus equipped with an electromagnet is described in the following Patent Document 1. In the plasma processing apparatus described in Patent Document 1, the electromagnet is provided above the chamber. The electromagnet has a coil wound around the central axis of the chamber. The central axis of the electromagnet extends in the vertical direction. The substrate is placed on a substrate support so that its center is located on the central axis.

By the way, plasma etching of a silicon film on a substrate is known as one type of plasma processing. The silicon film is etched by chemical species from a plasma generated from hydrogen bromide gas and/or chlorine gas. This type of plasma processing is described in the following Patent Document 2.

JP 2017-73518 A JP 2003-218093 A

This disclosure provides a technology that prevents the processing speed of plasma processing performed in a plasma processing apparatus equipped with an electromagnet having a coil wound around the central axis of a chamber from becoming locally high in the center of a substrate.

In one exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, a substrate support, a plasma generating unit, a first electromagnet assembly, and a second electromagnet assembly. The chamber has a central axis. The substrate support is disposed within the chamber. The center of the substrate on the substrate support is located on the central axis. The plasma generating unit is configured to generate plasma from a process gas supplied into the chamber. The first electromagnet assembly includes one or more first annular coils, is disposed on or above the chamber, and is configured to generate a first magnetic field within the chamber. The second electromagnet assembly includes one or more second annular coils, and is configured to generate a second magnetic field within the chamber. The second magnetic field reduces the intensity of the first magnetic field at the center of the substrate on the substrate support.

According to one exemplary embodiment, it is possible to prevent the processing speed of plasma processing performed in a plasma processing apparatus equipped with an electromagnet having a coil wound around the central axis of the chamber from being locally high in the center portion of the substrate.

1 is a schematic diagram of a plasma processing apparatus according to an exemplary embodiment; FIG. 4 is a plan view showing an example of a plurality of first electromagnets. FIG. 4 is a plan view showing an example of a second electromagnet. 1 is a flow diagram of a method for processing a substrate according to an exemplary embodiment. FIG. 2 is a partially enlarged cross-sectional view of an example substrate.

Various exemplary embodiments are described below.

In one exemplary embodiment, a plasma processing apparatus is provided. The plasma processing apparatus includes a chamber, a substrate support, a plasma generating unit, a first electromagnet assembly, and a second electromagnet assembly. The chamber has a central axis. The substrate support is disposed within the chamber. The center of the substrate on the substrate support is located on the central axis. The plasma generating unit is configured to generate plasma from a process gas supplied into the chamber. The first electromagnet assembly includes one or more first annular coils, is disposed on or above the chamber, and is configured to generate a first magnetic field within the chamber. The second electromagnet assembly includes one or more second annular coils, and is configured to generate a second magnetic field within the chamber. The second magnetic field reduces the intensity of the first magnetic field at the center of the substrate on the substrate support.

The density of negative ions in the plasma generated in the chamber tends to be high on or near the central axis of the chamber. When a magnetic field is formed in the chamber by the first electromagnet assembly while such a plasma is being generated, the processing speed of the substrate is locally high at the center of the substrate. In a plasma processing apparatus according to one exemplary embodiment, the strength of the magnetic field formed by the first electromagnet assembly at the point where the substrate placed on the substrate support intersects with the central axis of the chamber is reduced by the magnetic field formed by the second electromagnet assembly. As a result, the processing speed of the substrate is prevented from being locally high at the center.

In one exemplary embodiment, the second electromagnet assembly may be located below the substrate support.

In one exemplary embodiment, the second electromagnet assembly may be located above or above the chamber.

In one exemplary embodiment, the first electromagnet assembly may include a plurality of first annular coils, such as one or more first annular coils.

In one exemplary embodiment, the second electromagnet assembly may include multiple second annular coils, such as one or more second annular coils.

In one exemplary embodiment, the second magnetic field may counteract the strength of the first magnetic field at the center of the substrate on the substrate support.

In another exemplary embodiment, a method of processing a substrate in a chamber of a plasma processing apparatus is provided. The method includes a) placing a substrate on a substrate support in the chamber. The center of the substrate on the substrate support is located on a central axis of the chamber. The method further includes b) generating a plasma from a processing gas supplied into the chamber. The method further includes c) generating a first magnetic field in the chamber using a first electromagnet assembly disposed on or above the chamber during b). The first electromagnet assembly includes one or more first annular coils. The method further includes d) forming a second magnetic field in the chamber using a second electromagnet assembly during c). The second electromagnet assembly includes one or more second annular coils, and the second magnetic field reduces the intensity of the first magnetic field at the center of the substrate on the substrate support.

In one exemplary embodiment, the process gas may include hydrogen bromide gas and/or chlorine gas.

In one exemplary embodiment, step b) may include etching a silicon film on the substrate.

Various exemplary embodiments will be described in detail below with reference to the drawings. Note that the same or equivalent parts in each drawing will be given the same reference numerals.

A diagram showing a schematic diagram of a plasma processing apparatus according to an exemplary embodiment. The plasma processing apparatus 1 shown in FIG. 1 is a capacitively coupled plasma processing apparatus. The plasma processing apparatus 1 includes a chamber 10. The chamber 10 provides an internal space 10s therein. The internal space 10s can be depressurized by an exhaust device.

The chamber 10 includes a chamber body 12. The chamber 10 has a central axis Z, which will be described later. The chamber body 12 is a container having a substantially cylindrical shape. An internal space 10s is provided inside the chamber body 12. The chamber body 12 is formed from a conductive material, such as aluminum. The inner wall surface of the chamber body 12 is covered with a film that is resistant to plasma. This film is, for example, an anodized aluminum film or an yttrium oxide film. The chamber body 12 is electrically grounded.

The plasma processing apparatus 1 further includes a substrate support 14. The substrate support 14 is provided in the chamber 10. The substrate support 14 is configured to support a substrate W placed thereon. The substrate W has a diameter of, for example, 300 mm. The substrate W is placed on the substrate support 14 so that its center is located on the central axis Z. The central axis Z is the central axis of the chamber 10 and the internal space 10s, and extends in the vertical direction. The central axis of the substrate support 14 also approximately coincides with the central axis Z. That is, the center of the substrate W on the substrate support 14 is located on the central axis Z.

An edge ring 26 is mounted on the substrate support 14. The edge ring 26 is a substantially annular plate. The edge ring 26 is made of a material selected according to the plasma processing to be performed using the plasma processing apparatus 1. The edge ring 26 is made of, for example, silicon, silicon carbide, or silicon oxide. The substrate W is placed on the substrate support 14 and within the area surrounded by the edge ring 26.

In one embodiment, the substrate support 14 includes a base 14a and an electrostatic chuck 14b. The base 14a is formed from a conductive material such as aluminum. The base 14a has a generally disk-like shape.

The electrostatic chuck 14b is provided on the base 14a. The electrostatic chuck 14b includes a body and an electrode. The body of the electrostatic chuck 14b has an approximately disk shape and is formed from a dielectric material. The electrode of the electrostatic chuck 14b is a film-shaped electrode and is provided within the body of the electrostatic chuck 14b. A DC power supply is connected to the electrode of the electrostatic chuck 14b via a switch. When a DC voltage from the DC power supply is applied to the electrode of the electrostatic chuck 14b, an electrostatic attractive force is generated between the electrostatic chuck 14b and the substrate W. The substrate W is attracted to the electrostatic chuck 14b by the generated electrostatic attractive force and is held by the electrostatic chuck 14b.

The base 14a constitutes the lower electrode. The first high frequency power supply 18 is electrically connected to the base 14a via a first matching device 22. The first high frequency power supply 18 generates a first high frequency power for generating plasma. The frequency of the first high frequency power is, for example, 100 MHz, but is not limited to this. The first matching device 22 has a matching circuit for matching the output impedance of the first high frequency power supply 18 with the impedance of the load side (lower electrode side) of the first high frequency power supply 18. Note that the first high frequency power supply 18 may be connected to the upper electrode 16, rather than to the base 14a, via the first matching device 22.

The second high frequency power supply 20 is electrically connected to the base 14a via a second matching device 24. The second high frequency power supply 20 generates a second high frequency power. The second high frequency power has a frequency suitable for attracting ions to the substrate W. The frequency of the second high frequency power is lower than the frequency of the first high frequency power. The frequency of the second high frequency power is, for example, 3.2 MHz, but is not limited to this. The second matching device 24 has a matching circuit for matching the output impedance of the second high frequency power supply 20 with the impedance of the load side (lower electrode side).

The plasma processing apparatus 1 may further include an upper electrode 16. The upper electrode 16 is provided above the substrate support 14. The upper electrode 16 closes the upper opening of the chamber body 12. The upper electrode 16 also functions as a shower head. In one embodiment, the upper electrode 16 is formed with a buffer chamber 16a, a gas line 16b, and multiple gas holes 16c. Multiple gas holes 16c are connected to the buffer chamber 16a. These gas holes 16c extend downward and open toward the internal space 10s.

One end of the gas line 16b is connected to the buffer chamber 16a. The gas source group 40 is connected to the gas line 16b via the flow rate controller group 42 and the valve group 44. The gas source group 40, the flow rate controller group 42, and the valve group 44 constitute a gas supply unit. The gas source group 40 includes a plurality of gas sources. The flow rate controller group 42 includes a plurality of flow rate controllers. The plurality of flow rate controllers are mass flow controllers or pressure-controlled flow rate controllers. The valve group 44 includes a plurality of valves (e.g., opening and closing valves). The plurality of gas sources of the gas source group 40 are connected to the gas line 16b via the corresponding flow rate controllers of the flow rate controller group 42 and the corresponding valves of the valve group 44.

During operation of the plasma processing apparatus 1, a processing gas is supplied from a gas supply unit into the chamber 10. The pressure in the space in the chamber 10 is reduced by an exhaust unit. A first high-frequency power and/or a second high-frequency power is supplied to generate plasma from the processing gas in the internal space 10s. In one embodiment, the first high-frequency power is supplied from a first high-frequency power source to an upper electrode or a lower electrode via a first matcher, and the second high-frequency power is supplied from a second high-frequency power source to a lower electrode via a second matcher. Thus, the first and/or second high-frequency power sources can function as at least a part of a plasma generating unit configured to generate plasma from the processing gas supplied into the chamber. Then, the film on the substrate W is processed by chemical species from the plasma. The processing of the film on the substrate, i.e., the plasma processing, is, for example, plasma etching.

The plasma processing apparatus 1 includes a first electromagnet assembly 3 including one or more first electromagnets 30. The first electromagnet assembly 3 is configured to generate a first magnetic field in the chamber 10. In one embodiment, the plasma processing apparatus 1 includes a first electromagnet assembly 3 including a plurality of first electromagnets 30. In the embodiment shown in FIG. 1, the plurality of first electromagnets 30 includes electromagnets 31 to 34. FIG. 2 is a plan view showing an example of the plurality of first electromagnets. In FIG. 2, the plurality of first electromagnets 30 are shown as viewed from the internal space 10s side. The plurality of first electromagnets 30 are provided above or above the chamber 10. That is, the first electromagnet assembly 3 is disposed above or above the chamber 10. In the example shown in FIG. 1, the plurality of first electromagnets 30 are provided above the upper electrode 16.

Each of the one or more first electromagnets 30 includes a first coil. In the example shown in Figures 1 and 2, the electromagnets 31 to 34 each include coils 61 to 64 as the first coil. The coils 61 to 64 are wound around the central axis Z. That is, the first electromagnet assembly 3 includes first annular coils 61 to 64. The coils 61 to 64 are arranged coaxially at the same height position.

The first electromagnet assembly 3 further includes a bobbin 50 (or a yoke). The coils 61 to 64 are wound around the bobbin 50 (or a yoke). The bobbin 50 is formed of, for example, a magnetic material. The bobbin 50 has a columnar portion 51, a plurality of cylindrical portions 52 to 55, and a base portion 56. The base portion 56 has a substantially disk shape, and its central axis coincides with the central axis Z. The columnar portion 51 and the plurality of cylindrical portions 52 to 55 extend downward from the lower surface of the base portion 56. The columnar portion 51 has a substantially cylindrical shape, and its central axis coincides with the central axis Z. The radius L1 of the columnar portion 51 is, for example, 30 mm. The cylindrical portions 52 to 55 extend outside the columnar portion 51 in the radial direction with respect to the central axis Z.

Each of the cylindrical portions 52 to 55 has a cylindrical shape extending in the vertical direction. The central axis of the cylindrical portions 52 to 55 is approximately coincident with the central axis Z. That is, the cylindrical portions 52 to 55 are arranged coaxially. The radius L2 of the cylindrical portion 52, the radius L3 of the cylindrical portion 53, the radius L4 of the cylindrical portion 54, and the radius L5 of the cylindrical portion 55 are larger than the radius L1, and have a relationship of L2 < L3 < L4 < L5. For example, the radius L2, the radius L3, the radius L4, and the radius L5 are 76 mm, 127 mm, 178 mm, and 229 mm, respectively. The radius L2 is the distance between the central axis Z and the radial midpoint between the inner and outer peripheral surfaces of the cylindrical portion 52. The radius L3 is the distance between the central axis Z and the radial midpoint between the inner and outer peripheral surfaces of the cylindrical portion 53. Radius L4 is the distance between the central axis Z and the radial midpoint between the inner and outer circumferential surfaces of cylindrical portion 54. Radius L5 is the distance between the central axis Z and the radial midpoint between the inner and outer circumferential surfaces of cylindrical portion 55.

Coil 61 is wound along the outer circumferential surface of columnar portion 51 and is housed in the groove between columnar portion 51 and cylindrical portion 52. Coil 62 is wound along the outer circumferential surface of cylindrical portion 52 and is housed in the groove between cylindrical portion 52 and cylindrical portion 53. Coil 63 is wound along the outer circumferential surface of cylindrical portion 53 and is housed in the groove between cylindrical portion 53 and cylindrical portion 54. Coil 64 is wound along the outer circumferential surface of cylindrical portion 54 and is housed in the groove between cylindrical portion 54 and cylindrical portion 55.

A current source 70 is connected to the first coil of one or more first electromagnets 30. The supply and stop of current from the current source 70 to each of the first coils of one or more first electromagnets 30, the direction of the current, and the current value are controlled by the control unit Cnt. Note that when the plasma processing apparatus 1 includes multiple first electromagnets 30, a single current source may be connected to the first coil of each of the multiple first electromagnets 30, or different current sources may be connected to each of the first coils.

The one or more first electromagnets 30 form a magnetic field in the chamber 10 that is axially symmetrical with respect to the central axis Z. By controlling the current supplied to each of the one or more first electromagnets 30, it is possible to adjust the magnetic field strength distribution (or magnetic flux density) in the radial direction with respect to the central axis Z. This allows the plasma processing apparatus 1 to adjust the radial distribution of the density of the plasma generated in the chamber 10, and thereby adjust the radial distribution of the processing speed (e.g., etching rate) of the film on the substrate W.

The plasma processing apparatus 1 further includes a second electromagnet assembly 8 including one or more second electromagnets 80. The second electromagnet assembly 8 is configured to generate a second magnetic field within the chamber 10. The second magnetic field reduces the strength of the first magnetic field at the center of the substrate W on the substrate support 14. In the example shown in FIG. 1, the number of second electromagnets 80 is one. Below, an embodiment in which the plasma processing apparatus 1 includes one second electromagnet 80 will be described, but the number of second electromagnets 80 included in the plasma processing apparatus 1 may be multiple.

Figure 3 is a plan view showing an example of the second electromagnet. In Figure 3, the second electromagnet 80 is shown as viewed from the internal space 10s side. In one embodiment, the second electromagnet 80 is provided below the substrate support 14. That is, the second electromagnet assembly 8 is disposed below the chamber 10.

The second electromagnet 80 includes a coil 81 as a second coil. The coil 81 is wound around the central axis Z. That is, the second electromagnet assembly 8 includes a second annular coil 81. When the plasma processing apparatus 1 includes multiple second electromagnets 80, the second coils of each of the multiple second electromagnets 80 can be arranged coaxially around the central axis Z at the same height position.

The second electromagnet assembly 8 further includes a bobbin 90 (or a yoke). The coil 81 is wound around the bobbin 90 (or a yoke). The bobbin 90 is formed of, for example, a magnetic material. The bobbin 90 has a plurality of cylindrical portions 91-92 and a base portion 93. The base portion 93 has a substantially disk shape, and its central axis coincides with the central axis Z. The plurality of cylindrical portions 91-92 extend upward from the upper surface of the base portion 93. The cylindrical portions 91-92 are arranged coaxially around the central axis Z. The coil 81 is wound around the outer circumferential surface of the cylindrical portion 91 and is housed in a groove between the cylindrical portions 91 and 92.

A current source 100 is connected to the second coil. The supply and stop of current from the current source 100 to the second coil, the direction of the current, and the current value are controlled by the control unit Cnt. When the plasma processing apparatus 1 includes multiple second electromagnets 80, a single current source may be connected to the second coil of each of the multiple second electromagnets 80, or different current sources may be connected to each of the second coils.

The second electromagnet 80 forms a magnetic field that reduces the strength of the magnetic field formed by the one or more first electromagnets 30 at the location where the central axis Z intersects with the substrate W placed on the substrate support 14, i.e., where the center of the substrate W is located. The current supplied to the second electromagnet 80 is controlled to form such a magnetic field. In one embodiment, the second electromagnet 80 forms a magnetic field that sets the strength of the magnetic field formed by the one or more first electromagnets 30 at that location to zero.

In one embodiment, the plasma processing apparatus 1 may further include the above-mentioned control unit Cnt. The control unit Cnt may be a computer device including a processor, a storage unit such as a memory, an input device, a display device, a signal input/output interface, and the like. The control unit Cnt controls each part of the plasma processing apparatus 1. In the control unit Cnt, an operator can use the input device to input commands and the like to manage the plasma processing apparatus 1. In addition, the control unit Cnt can visualize and display the operating status of the plasma processing apparatus 1 using the display device. Furthermore, the storage unit stores a control program and recipe data. The control program is executed by the processor to execute various processes in the plasma processing apparatus 1. The processor executes the control program and controls each part of the plasma processing apparatus 1 according to the recipe data.

The density of negative ions in the plasma generated in the chamber 10 tends to be high on or near the central axis Z. When a magnetic field is formed in the chamber 10 by one or more first electromagnets 30 while such a plasma is being generated, the processing speed (e.g., etching rate) of the substrate W becomes locally high at the center of the substrate W. In the plasma processing apparatus 1, the strength of the magnetic field formed by the one or more first electromagnets 30 at the point where the substrate W placed on the substrate support 14 intersects with the central axis Z is reduced by the magnetic field formed by the second electromagnet 80. As a result, the processing speed of the substrate W is prevented from becoming locally high at its center.

In one embodiment, the plasma processing apparatus 1 may include a first electromagnet assembly 3 including a plurality of first electromagnets 30. In this embodiment, the radial distribution of the plasma density is adjusted by a composite magnetic field formed in the chamber 10 by the plurality of first electromagnets 30. Therefore, when the plasma processing apparatus 1 includes a first electromagnet assembly 3 including a plurality of first electromagnets 30, the radial distribution of the plasma density is highly controllable.

In one embodiment, the plasma processing apparatus 1 may include a second electromagnet assembly 8 including a plurality of second electromagnets 80. In this embodiment, a composite magnetic field is formed within the chamber 10 by the plurality of second electromagnets 80. This provides greater control over the distribution of the magnetic field strength within the chamber 10.

Below, a method for processing a substrate according to one exemplary embodiment will be described with reference to FIG. 4. FIG. 4 is a flow chart of a method for processing a substrate according to one exemplary embodiment. The method shown in FIG. 4 (hereinafter, referred to as "method MT") is performed using a plasma processing apparatus. The plasma processing apparatus used in performing method MT includes a first electromagnet assembly 3 including one or more first electromagnets as described above, and a second electromagnet assembly 8 including one or more second electromagnets. Below, method MT will be described using an example in which plasma processing apparatus 1 is used.

The method MT is performed with the substrate W placed on the substrate support 14. The substrate W is placed on the substrate support 14 so that its center is located on the central axis Z. FIG. 5 is a partially enlarged cross-sectional view of an example substrate. The substrate W shown in FIG. 5 has a film EF. The film EF is a film that is subject to plasma processing in the method MT. In one example, the film EF is a silicon film. The film EF may be a film formed from another material. The substrate W may further have a base region UR and a mask MSK. The film EF is provided on the base region UR. The mask MSK is provided on the film EF. The mask MSK is patterned. In one embodiment, the method MT is applied to the substrate W to transfer the pattern of the mask MSK to the film EF.

In the method MT, step ST1 is performed with the substrate W placed on the substrate support 14. In step ST1, plasma is generated from a processing gas in the chamber 10. In step ST1, the processing gas is supplied into the chamber 10. The processing gas used in step ST1 includes one or more gases selected for plasma processing of the substrate W. In one example, for plasma etching of the film EF, which is a silicon film, the processing gas may include hydrogen bromide gas and/or chlorine gas. In step ST1, the pressure in the chamber 10 is set to a specified pressure. Also, in step ST1, a first high frequency power and/or a second high frequency power is supplied to excite the processing gas and generate plasma from the processing gas.

To perform process ST1, the control unit Cnt controls the gas supply unit to supply a process gas into the chamber 10. To perform process ST1, the control unit Cnt controls the exhaust device to set the pressure in the chamber 10 to a specified pressure. To perform process ST1, the control unit Cnt also controls the first high frequency power supply 18 and/or the second high frequency power supply 20 to supply a first high frequency power and/or a second high frequency power.

In addition to step ST1, method MT includes steps ST2 and ST3. Steps ST2 and ST3 are performed while step ST1 is being performed. That is, steps ST2 and ST3 are performed when plasma is being generated from the processing gas in chamber 10.

In step ST2, a magnetic field is generated in the chamber 10 using a first electromagnet assembly 3 including one or more first electromagnets 30. The current supplied from the current source 70 to each of the one or more first electromagnets 30 is controlled by the control unit Cnt.

In step ST3, a magnetic field is formed in the chamber 10 using a second electromagnet assembly 8 including one or more second electromagnets 80. The current supplied from the current source 100 to each of the one or more second electromagnets 80 is controlled by the control unit Cnt. In step ST3, the one or more second electromagnets 80 form a magnetic field that reduces the strength of the magnetic field formed by the one or more first electromagnets 30 at the location where the central axis Z intersects with the substrate W placed on the substrate support 14, i.e., where the center of the substrate W is located. In one embodiment, the one or more second electromagnets 80 form a magnetic field that sets the strength of the magnetic field formed by the one or more first electromagnets 30 to zero at the location where the central axis Z intersects with the substrate W placed on the substrate support 14.

In method MT, a substrate W is processed by chemical species from a plasma in chamber 10 while a magnetic field is formed in chamber 10 by one or more first electromagnets and one or more second electromagnets. In one example of method MT, a film EF, which is a silicon film of substrate W, is etched by ions from a plasma formed from a process gas including hydrogen bromide gas and/or chlorine gas.

In method MT, the strength of the magnetic field formed by one or more first electromagnets 30 at the point where the substrate W intersects with the central axis Z is reduced by the magnetic field formed by the second electromagnets 80. Therefore, method MT prevents the processing speed of the substrate W from becoming locally high at its center. In one example in which the film EF, which is a silicon film, is etched by ions from a plasma formed from a processing gas containing hydrogen bromide gas and/or chlorine gas, the etching rate of the film EF at its center is prevented from becoming locally high.

Although various exemplary embodiments have been described above, various omissions, substitutions, and modifications may be made without being limited to the above-described exemplary embodiments. In addition, elements in different embodiments may be combined to form other embodiments.

For example, the second electromagnet assembly 8 including one or more second electromagnets may be provided above or on the chamber 10. In one embodiment, one or more of the electromagnets 31 to 34 may be used as a first electromagnet, and one or more other electromagnets of the electromagnets 31 to 34 may be used as a second electromagnet. That is, a first group including one or more annular coils of the annular coils 61 to 64 may be included in the first electromagnet assembly 3, and a second group including one or more other annular coils of the annular coils 61 to 64 may be included in the second electromagnet assembly 8. In this case, the second electromagnet assembly 8 is disposed at the same height as the first electromagnet assembly 3. Even in this case, the current supplied to the first coil of each first electromagnet and the second coil of each second electromagnet is controlled so that a magnetic field that reduces the strength of the magnetic field formed by the one or more first electromagnets at the above-mentioned location is formed by the one or more second electromagnets. For example, a current in a direction opposite to the direction of the current supplied to each first electromagnet is supplied to the coil of each second electromagnet. In one embodiment, the second electromagnet assembly 8 may be disposed at a different height than the first electromagnet assembly 3 above or on the chamber 10. For example, the second electromagnet assembly 8 may be disposed above or on the first electromagnet assembly 3, or may be disposed between the chamber 10 and the first electromagnet assembly 3.

From the foregoing, it will be understood that the various embodiments of the present disclosure have been described herein for purposes of illustration, and that various modifications may be made without departing from the scope and spirit of the present disclosure. Accordingly, the various embodiments disclosed herein are not intended to be limiting, with the true scope and spirit being indicated by the appended claims.

1...plasma processing apparatus, 10...chamber, 14...substrate support, 18...first high frequency power supply, 20...second high frequency power supply, 30...first electromagnet, 61-64...coil, 80...second electromagnet, 81...coil, Z...central axis.

Claims (8)

a chamber having a central axis;
a substrate support disposed within the chamber, the substrate support having a center on the substrate positioned on the central axis;
a plasma generating unit configured to generate plasma from a processing gas supplied into the chamber;
a first electromagnet assembly disposed on or above the chamber, the first electromagnet assembly including a first toroidal coil, a second toroidal coil surrounding the first toroidal coil, a third toroidal coil surrounding the second toroidal coil, and a fourth toroidal coil surrounding the third toroidal coil;
at least one first power source configured to supply a first current, a second current, a third current, and a fourth current to the first toroidal coil, the second toroidal coil, the third toroidal coil, and the fourth toroidal coil, respectively, to generate a first magnetic field in the chamber;
a second electromagnet assembly disposed below the substrate support, the second electromagnet assembly including a fifth toroidal coil longitudinally overlapping the first toroidal coil without any toroidal coil longitudinally overlapping the third toroidal coil and the fourth toroidal coil;
a second power supply configured to supply a fifth current to the fifth toroidal coil to generate a second magnetic field that reduces a strength of the first magnetic field at the center of the substrate on the substrate support ;
A plasma processing apparatus comprising: The plasma processing apparatus of claim 1, wherein the second power supply is configured to supply the fifth current to the fifth annular coil in a direction opposite to the directions of the first current, the second current, the third current, and the fourth current supplied to the first annular coil, the second annular coil, the third annular coil, and the fourth annular coil, respectively. The plasma processing apparatus according to claim 1 or 2, wherein the second power supply is configured to supply the fifth current to the fifth annular coil so as to prevent the processing speed of the substrate on the substrate support from being locally high in a central portion of the substrate. 1. A method for processing a substrate in a plasma processing apparatus, comprising:
The plasma processing apparatus includes:
a chamber having a central axis;
a substrate support disposed within the chamber, the substrate support having a center on the substrate positioned on the central axis;
a first electromagnet assembly disposed on or above the chamber, the first electromagnet assembly including a first toroidal coil, a second toroidal coil surrounding the first toroidal coil, a third toroidal coil surrounding the second toroidal coil, and a fourth toroidal coil surrounding the third toroidal coil;
a second electromagnet assembly disposed below the substrate support, the second electromagnet assembly including a fifth toroidal coil longitudinally overlapping the first toroidal coil without any toroidal coil longitudinally overlapping the third toroidal coil and the fourth toroidal coil;
Including,
The method comprises:
a) placing a substrate on the substrate support;
b) generating a plasma from a process gas supplied into the chamber;
c) during b), supplying a first current, a second current, a third current and a fourth current to the first toroidal coil, the second toroidal coil, the third toroidal coil and the fourth toroidal coil, respectively, to generate a first magnetic field in the chamber;
d) during c), supplying a fifth current to the fifth toroidal coil to form a second magnetic field in the chamber, the second magnetic field reducing a strength of the first magnetic field at the center of the substrate on the substrate support ;
A method comprising: The method according to claim 4, wherein in d), the fifth current is supplied in a direction opposite to the directions of the first current, the second current, the third current, and the fourth current supplied to the first toroidal coil, the second toroidal coil, the third toroidal coil, and the fourth toroidal coil, respectively. The method according to claim 4 or 5, wherein in d), the fifth current is supplied to suppress a processing speed of the substrate on the substrate support from being locally high in a central portion of the substrate. The method of claim 4, wherein the process gas includes hydrogen bromide and/or chlorine. The method of claim 7, wherein b) includes etching a silicon film on the substrate.

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