Plasma source device, substrate processing device, and control method

Abstract

Provided are a plasma source device that suppresses damage to a gas supply path, a substrate processing device, and a control method.　This plasma source device comprises: a gas supply path to which a processing gas is supplied from a gas supply unit, the gas supply path having an internal flow path through which the processing gas flows; and a plasma generation unit that generates plasma by magnetically exciting the processing gas in the gas supply path. The plasma generation unit has a magnetic core that surrounds the gas supply path, and a coil to which high-frequency power is supplied from a high-frequency power source, and which is wound around the magnetic core along the gas supply path.

Description

Plasma Source Device, Substrate Processing Device, and Control Method

[0001] The present disclosure relates to a plasma source device, a substrate processing device, and a control method.

[0002] Patent Document 1 discloses a high-frequency inductively coupled plasma source that introduces an alternating magnetic field formed by an excitation coil into a plasma generation chamber and generates plasma in the plasma generation chamber.

[0003] Japanese Patent Application Laid-Open No. 2004-158272

[0004] In one aspect, the present disclosure provides a plasma source device, a substrate processing device, and a control method that suppress damage to a gas supply path.

[0005] To solve the above problems, according to one aspect, a plasma source device includes a gas supply path having an internal flow path through which a processing gas is supplied from a gas supply unit, and a plasma generation unit that magnetically excites the processing gas in the gas supply path to generate plasma. The plasma generation unit includes a magnetic core surrounding the gas supply path, and a coil wound along the gas supply path with respect to the magnetic core and supplied with high-frequency power from a high-frequency power source.

[0006] According to one aspect, the present disclosure can provide a plasma source device, a substrate processing device, and a control method that suppress damage to a gas supply path.

[0007] An example of a schematic diagram showing a configuration example of a substrate processing device. An example of a perspective view of a plasma source device. An example of a perspective view of the plasma source device seen through a shield. An example of a perspective view of the magnetic core cut. An example of a cross-sectional view of the plasma source device. Another example of a cross-sectional view of the plasma source device. A diagram showing an example of the electromagnetic field distribution of the plasma source device. Another example of a perspective view of the plasma source device seen through a shield. Another diagram showing an example of the electromagnetic field distribution of the plasma source device.

[0008] Hereinafter, embodiments for implementing the present disclosure will be described with reference to the drawings. In each drawing, the same reference numerals are assigned to the same components, and redundant descriptions may be omitted.

[0009] [Substrate Processing Apparatus] An example of the substrate processing apparatus 1 will be explained using Figure 1. Figure 1 is an example of a schematic diagram showing an example of the configuration of the substrate processing apparatus 1. The substrate processing apparatus 1 is a device that, for example, supplies remote plasma into a processing container 2 under reduced pressure to perform a desired process (film deposition, etching, cleaning, etc.).

[0010] The substrate processing apparatus 1 includes a processing container 2, a mounting table 3, an exhaust unit 4, a plasma source device 5, a gas supply unit 6, a high-frequency power supply 7, and a control unit 8.

[0011] The processing container 2 houses the mounting table 3 and forms a processing space 2s inside it. The mounting table 3 supports the substrate W to be processed. The exhaust unit 4 is connected to a gas outlet 2e provided in the processing container 2 and exhausts the gas inside the processing container 2. The exhaust unit 4 also has a pressure regulating valve, a vacuum pump, etc., to adjust the pressure inside the processing space 2s.

[0012] The plasma source device 5 is a device that receives processing gas from the gas supply unit 6 and high-frequency power for plasma generation from the high-frequency power supply 7 to generate inductively coupled plasma (ICP) of the processing gas, and supplies the generated plasma of the processing gas to the processing space 2s in the processing container 2. Details of the plasma source device 5 will be described later with reference to Figure 2, etc.

[0013] The gas supply unit 6 includes a gas supply source 61 for storing the processed gas and a flow rate controller 62. The gas supply unit 6 supplies the processed gas, whose flow rate has been adjusted by the flow rate controller 62, to the gas supply path 51 of the plasma source device 5 (see Figure 3, etc., described later).

[0014] The high-frequency power supply 7 supplies high-frequency power for plasma generation to the coil 53 of the plasma source device 5 (see Figure 3, etc., described later).

[0015] The control unit 8 is, for example, a computer and includes a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), auxiliary storage device, etc. The CPU operates based on a program stored in the ROM or auxiliary storage device and controls the operation of the substrate processing device 1. The control unit 8 may be located inside or outside the substrate processing device 1. If the control unit 8 is located outside the substrate processing device 1, the control unit 8 can control the substrate processing device 1 by communication means such as wired or wireless.

[0016] For example, the control unit 8 adjusts the processing space 2s to a predetermined pressure by controlling the exhaust unit 4 (pressure regulating valve, vacuum pump). The control unit 8 also supplies the plasma of the processing gas from the plasma source device 5 to the processing space 2s by controlling the flow rate controller 62 and the high-frequency power supply 7 of the gas supply unit 6.

[0017] The plasma source device 5 supplies a plasma (remote plasma) of a processing gas to the processing space 2s for performing a desired treatment (film deposition, etching, etc.) on the substrate W. However, the plasma source device 5 is not limited to this; for example, it also supplies a plasma (remote plasma) of a cleaning gas to the processing space 2s for cleaning the inside of the processing container 2.

[0018] [Plasma Source Device 5] Next, the plasma source device 5 will be described using Figures 2 to 6. Figure 2 is an example of a perspective view of the plasma source device 5. Figure 3 is an example of a perspective view of the plasma source device 5 after passing through the shield 54. Figure 4 is an example of a perspective view of the magnetic core 52 after cross-section. Figure 5 is an example of a cross-sectional view of the plasma source device 5. Figure 6 is an example of another cross-sectional view of the plasma source device 5. Note that in Figure 3, the passed shield 54 is shown with a dashed line. Also, Figures 4 and 5 are views taken by cutting at the position of the dashed line in Figure 3. Also, Figure 6 is a view taken by cutting at the position of the double dashed line in Figure 3.

[0019] The plasma source device 5 includes a gas supply path 51, a magnetic core 52, a coil 53, and a shield 54. The magnetic core 52 and coil 53 constitute a plasma generation unit that generates plasma by magnetically exciting a processing gas in the gas supply path 51.

[0020] The gas supply passage 51 is composed of pipes 511 to 513, each having an internal flow path 51a (see Figures 5 and 6) through which the processing gas flows. The gas supply passage 51 also has a plasma excitation section 51b (see Figures 5 and 6) in the portion covered by the magnetic core 52. The internal flow path 51a of the plasma excitation section 51b functions as a reactor (reaction chamber) that generates plasma. In the example shown in Figures 5 and 6, the gas supply passage 51 includes pipes 511 to 513, which are connected in series.

[0021] Furthermore, the plasma excitation section 51b of the gas supply passage 51 has gaps (magnetic field transmission spaces) 514 and 515 having a predetermined width. In the example shown in Figures 5 and 6, an annular gap 514 is formed between pipe 511 and pipe 512, communicating from the outer circumference to the inner circumference of the gas supply passage 51. The gap 514 is formed over the entire circumference of the gas supply passage 51. Also, an annular gap 515 is formed between pipe 512 and pipe 513, communicating from the outer circumference to the inner circumference of the gas supply passage 51. The gap 515 is formed over the entire circumference of the gas supply passage 51. Note that in the example shown in Figures 5 and 6, the case in which two gaps 514 and 515 are provided in the plasma excitation section 51b of the gas supply passage 51 is described as an example, but it is not limited to this. It is sufficient to have one or more gaps (514, 515) provided in the plasma excitation section 51b of the gas supply passage 51.

[0022] Here, the pipes 511 to 513 of the gas supply passage 51 are made of a non-magnetic metal material such as aluminum. As a result, the pipes 511 to 513 shield against the electric field of the coil 53 from penetrating the internal flow path 51a. The gas supply passage 51 may also be grounded.

[0023] Furthermore, the gaps (magnetic field transmission spaces) 514 and 515 provided in the gas supply passage 51 transmit the magnetic fields of the coil 53 and the magnetic core 52 to the internal flow path 51a. In addition, the magnetic fields (magnetic flux) from the coil 53 and the magnetic core 52 are transmitted from the outer circumference to the inner circumference of the internal flow path 51a of the gas supply passage 51, forming a magnetic field in the internal flow path 51a, and the structure also shields the electric field from the coil 53.

[0024] For example, gaps 514 and 515 have a stepped structure. Specifically, gaps 514 and 515 have a structure in which the opening positions on the outer circumference and the opening positions on the inner circumference are located at different positions in the axial direction (direction of flow of the processed gas) of the gas supply passage 51. Also, in the example shown in Figures 5 and 6, gaps 514 and 515 have a crank shape. Gap 514 has a first gap 514a formed radially inward from the opening position on the outer circumference of the gas supply passage 51, a second gap 514b formed radially outward from the opening position on the inner circumference of the gas supply passage 51, and a third gap 514c formed in the axial direction of the gas supply passage 51, connecting the first gap 514a and the second gap 514b. The gap 515 has a first gap 515a formed from the outer circumference opening towards the radially inward side of the gas supply passage 51, a second gap 515b formed from the inner circumference opening towards the radially outward side of the gas supply passage 51, and a third gap 515c formed in the axial direction of the gas supply passage 51, connecting the first gap 515a and the second gap 515b. The outer circumference opening of the gap 514 is located upstream of the gas supply passage 51 compared to the inner circumference opening. The outer circumference opening of the gap 515 is located downstream of the gas supply passage 51 compared to the inner circumference opening. The orientation of the stepped structure is not limited to these, and may be reversed.

[0025] Furthermore, the gas supply passage 51 has a structure that prevents the processing gas flowing through the gas supply passage 51 from leaking out of the gaps 514 and 515. Specifically, dielectric rings 55 and 56 are interposed in the gaps 514 and 515. The dielectric rings 55 and 56 have an annular shape (washer shape) and are made of a dielectric material such as alumina. Dielectric ring 55 is sandwiched between pipes 511 and 512, sealing the gap 514 to prevent processing gas leakage, while allowing the magnetic field (magnetic flux) from the coil 53 and magnetic core 52 to pass through. Dielectric ring 56 is sandwiched between pipes 512 and 513, sealing the gap 515 to prevent processing gas leakage, while allowing the magnetic field (magnetic flux) from the coil 53 and magnetic core 52 to pass through. Although the dielectric ring 55 has been described as being placed in the second gap 514b on the inner circumference side, it is not limited to this and may be placed in any of the gaps 514. Similarly, although the dielectric ring 56 has been described as being placed in the second gap 515b on the inner circumference side, it is not limited to this and may be placed in any of the gaps 515.

[0026] The magnetic core 52 is made of a magnetic material such as ferrite and is formed in an annular shape with a through hole in the center. The gas supply passage 51 is inserted through the through hole in the magnetic core 52. In other words, the magnetic core 52 is formed in an annular shape so as to surround the gas supply passage 51. Furthermore, the magnetic core 52 is formed in an annular shape so as to surround the plasma excitation section 51b where the gaps 514, 515 of the gas supply passage 51 are formed. The magnetic core 52 is formed in a rectangular annular shape, for example, with wall portions 521, 522, 523, 524. However, the shape of the magnetic core 52 is not limited to this, and it may be configured to be formed in a circular annular shape.

[0027] The gas supply passage 51 has two opposing planar sections 51S. The wall section 522 is positioned to contact one of the planar sections 51S of the gas supply passage 51. The wall section 524 is positioned to contact the other planar section 51S of the gas supply passage 51. In other words, a heat transfer section is formed between the gas supply passage 51 and the magnetic core 52. Furthermore, positioning is made easier by bringing the gas supply passage 51 and the magnetic core 52 into contact at the planar sections 51S. Note that the wall section 521 is positioned so as not to contact the gas supply passage 51. The wall section 523 may or may not be in contact with the gas supply passage 51.

[0028] By forming a flat portion 51S in the gas supply passage 51 and bringing it into contact with the wall portions 522 and 524 of the magnetic core 52, the distance between the internal flow path 51a of the gas supply passage 51 and the magnetic core 52 can be reduced, thereby enabling optimal plasma excitation.

[0029] Furthermore, by bringing the gas supply path 51 into contact with the magnetic core 52, the heat transfer between the gas supply path 51 and the magnetic core 52 can be improved. In other words, the heat generated by the coil 53 and the magnetic core 52 when high-frequency power is supplied to the coil 53 can be dissipated to the gas supply path 51.

[0030] The coil 53 is formed by winding it around the wall portion 521 of the magnetic core 52. One end of the coil 53, wire 531, and the other end, wire 532, are connected to the high-frequency power supply 7. In other words, one end of the coil 53 is connected to wire 531, and the other end is connected to wire 532. Of the wires 531 and 532, one may be connected to the high-frequency power supply 7 and the other to ground (GND). The coil 53 is made of a conductive material such as copper. The frequency of the high-frequency power supplied from the high-frequency power supply 7 to the coil 53 is preferably in the range of, for example, 100 kHz to 13 MHz. This reduces magnetic loss in the magnetic core 52.

[0031] Furthermore, as shown in Figure 4, the coil 53 may be formed in a helical shape while moving the winding position laterally along the wall portion 521 (in the direction of the central axis of the coil 53 being wound) (toroidal type). Alternatively, the coil 53 may be formed so that the coil wires overlap at the same position on the wall portion 521 (spiral type). Also, the coil 53 may be wound entirely or partially in a toroidal manner, entirely or partially in a spiral manner, or a combination of toroidal and spiral winding. In order to supply a magnetic field to the internal flow path 51a, the winding direction of the coil 53 (the direction in which the wiring of the coil 53 on the side close to the gas supply path 51 extends) is perpendicular to the gaps 154 and 155. Since the gaps 154 and 155 and the internal flow path 51a are perpendicular to each other, the winding direction of the coil 53 and the direction of the internal flow path 51a (the axial direction of the internal flow path 51a) are the same. In other words, the coil 53 is wound in a direction along the internal flow path 51a.

[0032] The shield 54 is formed to surround the magnetic core 52. The shield 54 shields against electric and magnetic fields from the coil 53 and the magnetic core 52. The shield 54 is made of a non-magnetic metal material such as aluminum. The shield 54 may be grounded. The shield 54 may also be electrically connected to the gas supply line 51.

[0033] Figure 7 shows an example of the electromagnetic field distribution of the plasma source device 5. Here, the electromagnetic field strength is indicated by the density of the dots. Note that Figure 7 shows an example of the electromagnetic field distribution in a plane cut at the position of the dashed line in Figure 3.

[0034] The control unit 8 controls the gas supply unit 6 to supply the processing gas to the gas supply path 51, and also controls the high-frequency power supply 7 to supply high-frequency power to the coil 53. By supplying high-frequency power from the high-frequency power supply 7 to the coil 53, an annular magnetic flux is formed in the magnetic core 52. The magnetic flux (magnetic field) formed in the magnetic core 52 forms a magnetic field in the internal flow path 51a of the plasma excitation unit 51b via the gaps (magnetic field transmission spaces) 514, 515 (see Figure 7).

[0035] This magnetic field generates a plasma current in the axial direction of the gas supply path 51 within the internal channel 51a. This plasma current ignites and excites the plasma of the processing gas within the internal channel 51a.

[0036] Here, we will describe a plasma source device according to the reference example. In the plasma source device according to the reference example, a coil is wound directly around the outside of a dielectric pipe through which the processing gas flows, and high-frequency power is supplied to the coil to generate inductively coupled plasma (ICP) of the processing gas in the internal flow path of the dielectric pipe.

[0037] In the plasma source device described in the reference example, high-voltage high-frequency power is supplied to the coil not only during plasma ignition but also during plasma ignition. As a result, the plasma of the processing gas generated in the internal flow path of the dielectric pipe and the coil's electric field couple, accelerating ions from the plasma toward the inner wall surface of the dielectric pipe. These accelerated ions collide with the inner wall surface of the dielectric pipe, damaging it. In particular, when NF is used as the processing gas... ３ When using reducing gases such as gases, the inner wall surface of dielectric piping is worn down by reactive ion etching.

[0038] In contrast, the plasma source device 5 shown in Figures 2 to 7 generates a plasma current in the axial direction of the gas supply path 51 within the internal flow path 51a by coupling the magnetic field (magnetic flux) of the magnetic core 52 with the plasma through gaps (magnetic field transmission spaces) 514 and 515, and the plasma is ignited and excited in the internal flow path 51a of the plasma excitation unit 51b by the magnetic field.

[0039] Furthermore, in the plasma source device 5, the electric field is shielded by pipes 511 to 513 made of non-magnetic metal material such as aluminum, and the electric field is also shielded by the structure (stepped structure, crank shape) of the gaps (magnetic field transmission spaces) 514 and 515, thereby shielding the coil electric field from entering the internal flow path 51a. In other words, coupling between the plasma of the processing gas generated in the internal flow path 51a of the gas supply path 51 (pipes 511 to 513) and the coil electric field is prevented, the acceleration of ions from the plasma toward the inner wall surface of the dielectric pipe is suppressed, the collision of accelerated ions with the inner wall surface of the gas supply path 51 (pipes 511 to 513) is suppressed, and damage to the inner wall surface of the gas supply path 51 (pipes 511 to 513) is suppressed. In other words, the frequency of replacement of the gas supply path 51 can be reduced.

[0040] Furthermore, by narrowing the width of the gaps 514 and 515, the electric field can be shielded, reducing damage to the inner wall surface of the gas supply passage 51. Here, let λ be the wavelength of the high-frequency power supplied to the coil 53. The width of the gaps 514 and 515 (axial width of the first gaps 514a and 515a, axial width of the second gaps 514b and 515b, and radial width of the third gaps 514c and 515c) is preferably λ / 100 or less.

[0041] On the other hand, by widening the gaps 514 and 515, it becomes easier to supply a magnetic field into the internal flow path 51a, thereby improving the power efficiency when generating plasma. For this reason, it is preferable that the width of the gaps 514 and 515 be in the range of, for example, 0.5 mm to 2 mm.

[0042] Furthermore, in the plasma excitation section 51b of the gas supply passage 51 covered by the magnetic core 52, it is preferable that the gas supply passage 51 is configured as a single, unbranched gas supply passage 51. This shortens the residence time of the plasma and suppresses damage to the inner wall surface of the gas supply passage 51 (pipes 511 to 513).

[0043] Next, another example of the plasma source device will be described with reference to FIG. 8. FIG. 8 is another example of a perspective view of the plasma source device 5A that has passed through the shield 54. The plasma source device 5A includes a gas supply path 51, a magnetic core 52A, a coil 53, and a shield 54. That is, the plasma source device 5A shown in FIG. 8 has a different shape of the magnetic core 52A compared to the plasma source device 5 shown in FIG. 3 and the like.

[0044] The magnetic core 52A has an annular portion 525, an annular portion 526, and a connecting portion 527. The annular portion 525 is formed in an annular shape (rectangular annular shape) so as to surround the gap 514. The annular portion 526 is formed in an annular shape (rectangular annular shape) so as to surround the gap 515. The connecting portion 527 is formed so as to connect the annular portion 526 and the connecting portion 527. In other words, the annular magnetic core in the intermediate portion 51c (see FIG. 7) between the gap 514 and the gap 515 has been deleted.

[0045] The coil 53 is formed by winding around the annular portion 525, the annular portion 526, and the connecting portion 527 of the magnetic core 52A.

[0046] FIG. 9 is a diagram showing an example of the electromagnetic field distribution of the plasma source device 5A. Here, the electromagnetic field strength is indicated by the density of the dots. Note that FIG. 9 shows an example of the electromagnetic field distribution on the plane cut at the position of the dashed-dotted line in FIG. 8.

[0047] Since the annular magnetic core in the intermediate portion 51c (see FIG. 7) between the gap 514 and the gap 515 has been deleted, annular magnetic fluxes are formed in the annular portions 525 and 526 that cover the gaps (magnetic field transmission spaces) 514 and 515. Thereby, magnetic loss can be reduced and the power efficiency when generating plasma can be improved. Also, by connecting the gap 514 and the gap 515 with the connecting portion 527, magnetic flux leakage can be suppressed, magnetic loss can be reduced, and the power efficiency when generating plasma can be improved.

[0048] Note that the shape of the magnetic core is not limited to the structure shown in FIG. 8, and a configuration in which annular magnetic cores (corresponding to the annular portions 525 and 526) are provided corresponding to the gaps (magnetic field transmission spaces) 514 and 515 may be adopted.

[0049] The above description concerns a substrate processing apparatus 1 equipped with plasma source devices 5 and 5A. However, this disclosure is not limited to the above embodiments, and various modifications and improvements are possible within the scope of the gist of this disclosure as described in the claims.

[0050] Furthermore, this application claims priority based on Japanese Patent Application No. 2024-189150, filed on 28 October 2024, and the entire contents of these Japanese Patent Applications are incorporated herein by reference.

[0051] W Substrate 1 Substrate processing device 2 Processing container 3 Mounting table 4 Exhaust section 5, 5A Plasma source device 6 Gas supply section 7 High-frequency power supply 8 Control unit 51 Gas supply path 51a Internal flow path 51b Plasma excitation section 51S Planar section 52, 52A Magnetic core (plasma generation section) 53 Coil (plasma generation section) 54 Shield 55, 56 Dielectric ring 511-513 Piping 514, 515 Gap (magnetic field transmission space) 521, 522, 523, 524 Wall section 525, 526 Annular section 527 Connection section

Claims

1. A plasma source device comprising: a gas supply path having an internal channel through which a processing gas is supplied from a gas supply unit; and a plasma generation unit generating plasma by magnetically exciting the processing gas in the gas supply path, wherein the plasma generation unit comprises a magnetic core surrounding the gas supply path and a coil wound around the magnetic core along the gas supply path, to which high-frequency power is supplied from a high-frequency power supply.

2. The plasma source device according to claim 1, wherein the gas supply path has a plasma excitation section in the portion covered by the magnetic core.

3. The plasma source apparatus according to claim 2, wherein the plasma excitation section has a predetermined width and a magnetic field transmission space for transmitting a magnetic field to the internal channel.

4. The width of the magnetic field transmission space is λ / 100 or less, where λ is the wavelength of the high-frequency power, according to claim 3.

5. The plasma source apparatus according to claim 3, wherein the magnetic field transmission space has a structure in which the opening position on the outer circumference side of the gas supply path and the opening position on the inner circumference side of the gas supply path are provided at different positions in the axial direction of the gas supply path.

6. The plasma source apparatus according to claim 3, further comprising a dielectric ring in the magnetic field transmission space.

7. The plasma source device according to claim 1, further comprising a heat transfer section between the gas supply path and the magnetic core.

8. The plasma source device according to claim 1, wherein the magnetic core is formed in an annular shape having a through hole, and the gas supply passage is inserted through the through hole of the magnetic core.

9. The plasma source apparatus according to claim 1, wherein the coil is wound all or part of the way around the magnetic core in a spiral or toroidal manner.

10. A substrate processing apparatus comprising: a processing container; a gas supply unit for supplying a processing gas; a high-frequency power supply for supplying high-frequency power; and a plasma source device for supplying plasma of the processing gas to the processing container, wherein the plasma source device comprises: a gas supply path having an internal flow path through which the processing gas is supplied from the gas supply unit; and a plasma generation unit generating plasma by magnetically exciting the processing gas in the gas supply path, wherein the plasma generation unit comprises: a magnetic core surrounding the gas supply path; and a coil wound around the magnetic core along the gas supply path, to which the high-frequency power supply is supplied.

11. A control method for a plasma source device comprising: a gas supply path having an internal channel through which a processing gas is supplied from a gas supply unit; a magnetic core surrounding the gas supply path; and a coil wound around the magnetic core along the gas supply path, to which high-frequency power is supplied from a high-frequency power supply, the control method comprising: supplying the high-frequency power to the coil and generating plasma by magnetically exciting the processing gas in the gas supply path.

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