Substrate processing apparatus, method for manufacturing a semiconductor device, substrate processing method, and storage medium

Abstract

The present invention relates to a substrate processing apparatus, a method for manufacturing a semiconductor device, a substrate processing method, and a storage medium, which improve the in-plane uniformity of substrate processing. The substrate processing apparatus includes: a processing container that plasma-excites a processing gas; a gas supply system that supplies the processing gas into the processing container; and a coil that is arranged such that an interval between a first ground point and a second ground point is wound multiple times in a spiral shape along the outer periphery of the processing container and is supplied with high-frequency power. The coil is configured such that, in a direction from the first ground point toward the second ground point, in an interval up to one winding along the outer periphery of the processing container, that is, in a first winding interval, a coil interval distance, which is a distance from the inner circumference of the coil to the inner circumference of the processing container in an interval including a part of the first ground point, is longer than a coil interval distance in other intervals continuous with the interval including the part of the first ground point.

Description

Technical Field

[0001] The present disclosure relates to a substrate processing apparatus, a method for manufacturing a semiconductor device, a substrate processing method, and a storage medium. Background Art

[0002] Patent Document 1 describes a substrate processing apparatus that performs substrate processing by plasma-exciting a processing gas by supplying high-frequency power to a coil.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Pamphlet of International Publication No. 2019 / 082569 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] However, in the case of the above-described substrate processing apparatus, plasma density deviation in the in-plane direction of the substrate may occur near the ground point on the coil, resulting in a decrease in in-plane uniformity of substrate processing.

[0008] An object of the present disclosure is to provide a technique capable of improving the in-plane uniformity of substrate processing.

[0009] Solutions to the Problems

[0010] According to one aspect of the present disclosure, there is provided the following technique, including:

[0011] A processing container that plasma-excites a processing gas;

[0012] A gas supply system that supplies the processing gas into the processing container; and

[0013] A coil that is arranged such that an interval between a first ground point and a second ground point is wound multiple times in a spiral shape along an outer periphery of the processing container and is supplied with high-frequency power,

[0014] The coil is configured such that, in a direction from the first ground point toward the second ground point, in an interval up to one turn along the outer periphery of the processing container, that is, in a first winding interval, a coil interval distance, which is a distance from an inner periphery of the coil to an inner periphery of the processing container in an interval including a part of the first ground point, is longer than a coil interval distance in other intervals continuous with the interval including the part of the first ground point.

[0015] Effects of the Invention

[0016] According to the present disclosure, the in-plane uniformity of substrate processing can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic structural diagram of a substrate processing apparatus applicable to one embodiment of the present disclosure.

[0018] Figure 2 (A) of is a diagram showing a resonance coil of a comparative example of the present disclosure. Figure 2 (B) of is showing Figure 2 An explanatory diagram of the relationship between current and voltage in the resonance coil of (A) of.

[0019] Figure 3 (A) of is showing the use of Figure 2 A diagram of the state inside the processing furnace when the processing gas is plasma-excited using the resonance coil of (A) of. Figure 3 (B) of is Figure 3 A horizontal cross-sectional view of the lower end of the resonance coil of (A) of.

[0020] Figure 4 (A) of is a diagram showing a resonance coil applicable to one embodiment of the present disclosure. Figure 4 (B) of is showing Figure 4 An explanatory diagram of the relationship between current and voltage in the resonance coil of (A) of.

[0021] Figure 5 (A) of is showing the use of Figure 4 A diagram of the state inside the processing furnace when the processing gas is plasma-excited using the resonance coil of (A) of. Figure 5 (B) of is Figure 5 A horizontal cross-sectional view of the lower end of the resonance coil of (A) of.

[0022] Figure 6 It is a diagram showing the structure of a control unit (control part) of a substrate processing apparatus applicable to one embodiment of the present disclosure.

[0023] Figure 7 It is a flowchart showing a substrate processing process applicable to one embodiment of the present disclosure.

[0024] Figure 8 (A) of is a diagram showing the state inside the processing furnace when the processing gas is plasma-excited using a modified example of a resonance coil applicable to one embodiment of the present disclosure. Figure 8 (B) of is Figure 8 A horizontal cross-sectional view of the upper end of the resonance coil of (A) of.

[0025] Figure 9 (A) of is a diagram showing the state inside the processing furnace when the processing gas is plasma-excited using a modified example of a resonance coil applicable to one embodiment of the present disclosure. Figure 9 (B) of is Figure 9Horizontal cross-sectional view of the lower end of the resonance coil of (A).

[0026] Figure 10 It is a diagram showing the state inside a processing furnace during plasma excitation of a processing gas using a modified example of a resonance coil applicable to one embodiment of the present disclosure.

[0027] Figure 11 It is a diagram showing the state inside a processing furnace during plasma excitation of a processing gas using a modified example of a resonance coil applicable to one embodiment of the present disclosure.

[0028] Figure 12 It is a diagram showing the average film thickness and in-plane uniformity of a film formed on a substrate when substrate processing is performed using the resonance coil of this embodiment and the resonance coil of a comparative example, respectively.

[0029] In the figure:

[0030] 200 - wafer (substrate); 201 - processing chamber; 203 - processing container; 210 - upper container; 211 - lower container; 212 - resonance coil; 217 - susceptor (substrate stage); 273 - high-frequency power supply. Detailed implementation mode

[0031] <One embodiment of the present disclosure>

[0032] The following refers to Figures 1 to 7 One embodiment of the present disclosure will be described. In addition, the accompanying drawings used in the following description are all schematic diagrams, and the dimensional relationships of the elements shown in the figures, the ratios of the elements, etc. are not necessarily the same as the actual ones. Also, between the respective figures, the dimensional relationships of the elements, the ratios of the elements, etc. are not necessarily the same.

[0033] (1) Structure of the substrate processing apparatus

[0034] The following refers to Figure 1 The substrate processing apparatus 100 of one embodiment of the present disclosure will be described. The substrate processing apparatus of one embodiment of the present disclosure is configured to be able to perform an oxidation process on a film or a substrate mainly formed on a substrate surface.

[0035] (Processing chamber)

[0036] The substrate processing apparatus 100 includes a processing furnace 202 that performs plasma processing on a wafer 200 as a substrate. A processing container 203 that constitutes a processing chamber 201 is provided in the processing furnace 202. The processing container 203 includes: an upper container 210 of a dome shape as a first container, and a lower container 211 of a bowl shape as a second container. The upper container 210 covers the lower container 211 to form the processing chamber 201. The upper container 210 is formed of quartz. In addition, the upper container 210 constitutes a plasma container that forms a plasma generation space for plasma-exciting a processing gas.

[0037] In addition, a gate valve 244 is provided on a lower side wall of the lower container 211. It is configured such that when the gate valve 244 is opened, the wafer 200 can be carried into the processing chamber 201 via a carry-in / carry-out port 245 by a transfer mechanism, or the wafer 200 can be carried out of the processing chamber 201. The gate valve 244 is configured as a partition valve that maintains the airtightness inside the processing chamber 201 when closed.

[0038] The processing chamber 201 has: a plasma generation space provided with a resonance coil 212 as an electrode around it, and a substrate processing space that communicates with the plasma generation space and processes the wafer 200 as a substrate processing chamber. The plasma generation space is a space for generating plasma, and is a space in the processing chamber 201 that is above the lower end of the resonance coil 212 and below the upper end of the resonance coil 212. On the other hand, the substrate processing space is a space for processing the substrate using plasma, and is a space below the lower end of the resonance coil 212. In one embodiment of the present disclosure, it is configured such that the horizontal diameters of the plasma generation space and the substrate processing space are substantially the same.

[0039] (Base)

[0040] At the center of the bottom side of the processing chamber 201, a base 217 as a substrate mounting stage for mounting the wafer 200 is disposed. The base 217 is provided below the resonance coil 212 inside the processing chamber 201.

[0041] Inside the base 217, a heater 217b as a heating mechanism is integrally embedded. The heater 217b is configured to be able to heat the wafer 200 when energized.

[0042] The base 217 is electrically insulated from the lower container 211. In order to further improve the uniformity of the density of the plasma generated on the wafer 200 mounted on the base 217, an impedance adjustment electrode 217c is provided inside the base 217, and the impedance adjustment electrode 217c is grounded via an impedance variable mechanism 275 as an impedance adjustment unit.

[0043] A base lifting mechanism 268 is provided on the base 217, and the base lifting mechanism 268 includes a driving mechanism for lifting the base 217. Further, a through-hole 217a is provided in the base 217, and a wafer top pin 266 is provided on the bottom surface of the lower container 211. It is configured such that when the base 217 is lowered by the base lifting mechanism 268, the wafer top pin 266 can be ejected in the through-hole 217a without contacting the base 217.

[0044] (Gas supply section)

[0045] Above the processing chamber 201, that is, above the upper container 210, a gas supply head 236 is provided. The gas supply head 236 includes: a cap-shaped cover 233, a gas inlet 234, a buffer chamber 237, an opening 238, a shielding plate 240, and a gas outlet 239, and is configured to be able to supply a reaction gas into the processing chamber 201. The buffer chamber 237 has a function as a dispersion space for dispersing the reaction gas introduced through the gas inlet 234.

[0046] Connected to the gas inlet 234 in a confluent manner are: the downstream end of an oxygen-containing gas supply pipe 232a for supplying an oxygen-containing gas, the downstream end of a hydrogen-containing gas supply pipe 232b for supplying a hydrogen-containing gas, and the downstream end of an inert gas supply pipe 232c for supplying an inert gas. On the oxygen-containing gas supply pipe 232a, an oxygen-containing gas supply source 250a, a mass flow controller (MFC) 252a as a flow control device, and a valve 253a as an on-off valve are provided in sequence from the upstream side. On the hydrogen-containing gas supply pipe 232b, a hydrogen-containing gas supply source 250b, an MFC 252b, and a valve 253b are provided in sequence from the upstream side. On the inert gas supply pipe 232c, an inert gas supply source 250c, an MFC 252c, and a valve 253c are provided in sequence from the upstream side. A valve 243a is provided on the downstream side where the oxygen-containing gas supply pipe 232a, the hydrogen-containing gas supply pipe 232b, and the inert gas supply pipe 232c merge, and is connected to the upstream end of the gas inlet 234. It is configured such that by opening and closing the valves 253a, 253b, 253c, and 243a, the flow rates of the respective gases can be adjusted by the MFCs 252a, 252b, and 252c, and processing gases such as an oxygen-containing gas, a hydrogen-containing gas, and an inert gas can be supplied into the processing chamber 201 via the gas supply pipes 232a, 232b, and 232c.

[0047] Mainly, the gas supply unit (gas supply system) of one embodiment of the present disclosure is composed of a gas supply head 236, an oxygen-containing gas supply pipe 232a, a hydrogen-containing gas supply pipe 232b, an inert gas supply pipe 232c, MFCs 252a, 252b, 252c, valves 253a, 253b, 253c, and 243a. The gas supply unit (gas supply system) is configured to be able to supply a processing gas into the processing container 203.

[0048] In addition, the oxygen-containing gas supply system of one embodiment of the present disclosure is composed of a gas supply head 236, an oxygen-containing gas supply pipe 232a, MFC 252a, valves 253a, and 243a. Further, the hydrogen-containing gas supply system of one embodiment of the present disclosure is composed of a gas supply head 236, a hydrogen-containing gas supply pipe 232b, MFC 252b, valves 253b, and 243a. Further, the inert gas supply system of one embodiment of the present disclosure is composed of a gas supply head 236, an inert gas supply pipe 232c, MFC 252c, valves 253c, and 243a.

[0049] (Exhaust unit)

[0050] A gas exhaust port 235 is provided on the side wall of the lower container 211, and the gas exhaust port 235 is used to discharge the reaction gas from the processing chamber 201. The upstream end of a gas exhaust pipe 231 is connected to the gas exhaust port 235. On the gas exhaust pipe 231, the following are provided in sequence from the upstream side: an APC (Auto Pressure Controller) valve 242 as a pressure regulator (pressure regulating unit), a valve 243b as an on-off valve, and a vacuum pump 246 as a vacuum exhaust device. Mainly, the exhaust unit of one embodiment of the present disclosure is composed of the gas exhaust port 235, the gas exhaust pipe 231, the APC valve 242, and the valve 243b. In addition, the vacuum pump 246 may also be included in the exhaust unit.

[0051] (Plasma generation unit)

[0052] On the outer peripheral portion of the processing chamber 201, that is, on the outer side of the side wall of the upper container 210, a resonance coil 212 is provided in a manner of spirally winding multiple turns along the outer periphery of the upper container 210. An RF sensor 272, a high-frequency power supply 273, and a matcher 274 are connected to the resonance coil 212, and the matcher 274 performs impedance or transmission frequency matching of the high-frequency power supply 273.

[0053] The high-frequency power supply 273 is used to supply high-frequency power (RF power) to the resonance coil 212. The RF sensor 272 is provided on the output side of the high-frequency power supply 273 and monitors information on the forward wave or reflected wave of the supplied high-frequency power. The reflected wave power monitored by the RF sensor 272 is input to the matcher 274, and the matcher 274 controls the impedance of the high-frequency power supply 273 or the frequency of the output high-frequency power so as to minimize the reflected wave based on the information on the reflected wave input from the RF sensor 272.

[0054] The high-frequency power supply 273 includes: a power supply control unit (control circuit) that includes a high-frequency oscillation circuit and a preamplifier for specifying the oscillation frequency and output; and an amplifier (output circuit) for amplifying to a predetermined output. The power supply control unit controls the amplifier based on output conditions related to frequency and power preset through the operation panel. The amplifier supplies constant high-frequency power to the resonance coil 212 via a transmission line.

[0055] In order to form a standing wave of a predetermined wavelength, the winding diameter, winding pitch, and number of turns of the resonance coil 212 are set to be able to resonate at a constant wavelength. That is, the electrical length of the resonance coil 212 is set to a length equivalent to an integer multiple (1 times, 2 times,...) of one wavelength of the predetermined frequency of the high-frequency power supplied from the high-frequency power supply 273.

[0056] Specifically, considering the applied power, the generated magnetic field intensity, or the shape of the applicable device, etc., the resonance coil 212 is set to have an effective cross-sectional area of 50 to 300 mm and a coil diameter of 200 to 500 mm so as to be able to generate a magnetic field of about 0.01 to 10 gauss using high-frequency power of 800 kHz to 50 MHz and 0.1 to 5 kW. 2 and is wound 2 to 60 turns on the outer peripheral side of the chamber forming the plasma generation space.

[0057] As the raw material constituting the resonance coil 212, the following can be used: copper pipe, copper thin plate, aluminum pipe, aluminum thin plate, raw materials with copper or aluminum vapor-deposited on a polymer tape, etc. The resonance coil 212 is formed into a flat plate shape by an insulating material and is supported by a plurality of support members (not shown) standing upright on the upper end surface of the base plate 248.

[0058] Both ends of the resonance coil 212 are electrically grounded. One of the two ends of the resonance coil 212 is grounded at the first grounding point 302 as a fixed ground. In addition, the other end of the resonance coil 212 is grounded at the second grounding point 304. In order to finely adjust the electrical length of this resonance coil, the second grounding point 304 can also be grounded via a movable contact piece. In addition, in order to finely adjust the impedance of the resonance coil 212 when initially setting up the device or changing the processing conditions, a power supply unit is formed by a movable contact piece 215 between the two grounded ends of the resonance coil 212. In addition, by adjusting the position of the movable contact piece 215, the resonance characteristics of the resonance coil 212 are made substantially the same as those of the high-frequency power supply 273. By providing the resonance coil 212 with a variable grounding part and a variable power supply part, it becomes possible to more easily perform adjustments when adjusting the resonance frequency and load impedance of the processing chamber 201, as will be described later.

[0059] A shielding plate 223 is provided. This shielding plate 223 is used to shield the electric field outside the resonance coil 212, and a capacitance component (C component) required to form a resonance circuit is formed between the shielding plate 223 and the resonance coil 212. The shielding plate 223 is usually formed in a cylindrical shape using a conductive material such as aluminum alloy. The shielding plate 223 is arranged at a distance of 5 to 150 mm from the outer periphery of the resonance coil 212.

[0060] Mainly, the plasma generation part of one embodiment of the present disclosure is constituted by a resonance coil 212, an RF sensor 272, and a matcher 274. In addition, as the plasma generation part, a high-frequency power supply 273 may also be included.

[0061] Here, the plasma generation principle of the device of one embodiment of the present disclosure and the properties of the generated plasma will be specifically described. Regarding the plasma generation circuit constituted by the resonance coil 212, it can be constituted by a parallel resonance circuit of RLC. When the wavelength of the high-frequency power supplied from the high-frequency power supply 273 is the same as the electrical length of the resonance coil 212, regarding the resonance condition of the resonance coil 212, the reactance components caused by the capacitance component and inductance component of the resonance coil 212 are canceled out to become a pure resistance. However, in the above plasma generation circuit, when plasma is generated, due to changes in the capacitive coupling between the voltage part of the resonance coil 212 and the plasma, changes in the inductive coupling between the plasma generation space and the plasma, the excitation state of the plasma, etc., the actual resonance frequency will change slightly.

[0062] Therefore, in one embodiment of the present disclosure, in order to compensate for the resonance deviation in the resonance coil 212 during plasma generation from the power supply side, it has the following function: the reflected wave power from the resonance coil 212 during plasma generation is detected by the RF sensor 272, and based on the detected reflected wave power, the matcher 274 corrects the output of the high-frequency power supply 273.

[0063] Specifically, the matcher 274 increases or decreases the impedance or the transmission frequency of the high-frequency power supply 273 based on the reflected wave power from the resonance coil 212 at the time of plasma detection in the RF sensor 272 so that the reflected wave power is minimized. When controlling the impedance, the matcher 274 is composed of a variable capacitor control circuit that corrects a preset impedance, and when controlling the frequency, the matcher 274 is composed of a frequency control circuit that corrects the oscillation frequency of the preset high-frequency power supply 273. In addition, the high-frequency power supply 273 and the matcher 274 may be integrated.

[0064] According to this structure, for the resonance coil 212 of one embodiment of the present disclosure, high-frequency power including the actual resonance frequency of the resonance coil including plasma (or high-frequency power is supplied in a manner matching the actual impedance of the resonance coil including plasma) is supplied, and thus a standing wave in a state where the phase voltage and the anti-phase voltage are always canceled is formed. When the electrical length of the resonance coil 212 is the same as the wavelength of the high-frequency power, the highest phase current is generated at the electrical midpoint of the coil (the node where the voltage is zero). Therefore, near the electrical midpoint, there is substantially no capacitive coupling with the processing chamber wall and the susceptor 217, and an annular inductive plasma with an extremely low electric potential is formed.

[0065] (Winding diameter of the resonance coil)

[0066] Next, the winding diameter of the resonance coil 212 of one embodiment of the present disclosure will be described. As described above, the lower end of the resonance coil 212 is grounded at the first ground point 302, and the upper end of the resonance coil 212 is grounded at the second ground point 304. That is, both ends of the resonance coil 212 are grounded at the first ground point 302 and the second ground point 304, respectively, and the first ground point 302 is provided below the second ground point 304. The resonance coil 212 is configured to supply high-frequency power and is arranged such that the section between the first ground point 302 and the second ground point 304 is wound in a spiral shape around the outer periphery of the processing container 203 for multiple turns. Here, "along the outer periphery of the processing container 203" means a state where the resonance coil 212 is close to the outer periphery (outer surface, outer wall) of the processing container 203 to such an extent that the high-frequency electromagnetic field generated by the resonance coil 212 substantially plasma-excites the processing gas in the processing container 203.

[0067] <Winding diameter of the resonance coil of the comparative example>

[0068] First, for an example in which the resonance coil 412 of the comparative example is used instead of the resonance coil 212 of one embodiment of the present disclosure in the substrate processing apparatus 100, refer to Figure 2 of (A), Figure 2 of (B), Figure 3 of (A) andFigure 3 Explanation will be given for (B).

[0069] Regarding the resonance coil 412 of the comparative example, as Figure 2 shown in (A), the winding diameter is constant and the same at each position on the resonance coil 412. That is, when the distance from the inner wall surface (inner peripheral surface) of the upper container 210 to the inner diameter side surface of the resonance coil 412 (the surface facing the side wall of the upper container 210, that is, the inner peripheral surface) is set as d1, in this comparative example, d1 is always constant and the winding diameter is the same.

[0070] Regarding the structure of this comparative example, except for the winding diameter, other aspects are the same as those of the resonance coil 212 of one embodiment of the present disclosure. A power supply point is provided on the circuit of the resonance coil 412, high-frequency power is supplied from the high-frequency power supply 273, and a standing wave of current and voltage having a length equivalent to, for example, one wavelength of the high-frequency power is formed in the section between the first ground point 302 and the second ground point 304 on the circuit of the resonance coil 412. In Figure 2 the waveform on the left side of (B), the dotted line represents the current and the solid line represents the voltage. As Figure 2 shown in the waveform on the left side of (B), at the first ground point 302 and the second ground point 304 of the resonance coil 412 and their midpoint (i.e., the electrical midpoint), the amplitude of the standing wave of the current reaches the maximum.

[0071] A high-frequency magnetic field is formed near the midpoint of the resonance coil 412 where the amplitude of the current reaches the maximum, and the high-frequency electromagnetic field induced by this high-frequency magnetic field causes the processing gas supplied into the plasma generation space in the upper container 210 to discharge. Along with this discharge, the processing gas is excited, and thus plasma of the processing gas is generated near the midpoint of the resonance coil 412. Hereinafter, the plasma of the processing gas generated by the high-frequency electromagnetic field formed near the position (region) where the amplitude of the current is large is referred to as inductively coupled plasma (ICP (Inductively Coupled Plasma)). As Figure 3 shown in (A), in the space along the inner wall surface in the upper container 210, the ICP is generated in a ring shape in the region near the midpoint of the resonance coil 412, and the ICP with a uniform plasma density is generated in the in-plane direction of the wafer 200.

[0072] Here, as Figure 2 shown in (A) and Figure 2As shown in (B), near the first grounding point 302 on the lower end side of the resonance coil 412 or near the second grounding point 304 on the upper end side of the resonance coil 412, the amplitude of the current (magnetic field) also reaches the maximum, forming a high-frequency electromagnetic field. However, on the upper end side and the lower end side of the resonance coil 412, the intervals where the amplitude of the respective currents is large (for example, intervals above 80% of the maximum amplitude) are narrower than the intervals where the amplitude of the current near the midpoint of the resonance coil 412 is large (for example, intervals above 80% of the maximum amplitude). Specifically, for example, regarding the length of the interval where the amplitude of the current reaches 80% or more of the maximum amplitude, on the upper end side and the lower end side of the resonance coil 412, it may be about half of that near the midpoint of the resonance coil 412. At this time, on the upper end side and the lower end side of the resonance coil 412, as Figure 3 shown in (A) and Figure 3 shown in (B), the ICP with a high plasma density may not be generated in a manner that forms a complete loop along the inner circumference of the processing container 203, but may be generated only in a partial area in the inner circumferential direction of the processing container 203. That is, it may cause the ICP with a high plasma density to be generated in a state of being unevenly biased in the inner circumferential direction of the processing container 203.

[0073] In addition, as Figure 2 shown in (B), regarding the distribution of the plasma density in the inner circumferential direction of the processing container 203 for the ICPs generated on the upper end side and the lower end side respectively, this distribution has a bias where the plasma density significantly increases at the position corresponding to the first grounding point 302 where the amplitude of the current reaches the maximum and at the position corresponding to the second grounding point 304. In this regard, regarding the ICP generated near the midpoint, with the midpoint as the center, the distribution of the plasma density is formed to be substantially uniform along the entire inner circumferential direction of the processing container 203. In contrast, regarding the ICPs generated on the upper end side and the lower end side respectively, near the first grounding point 302 and the second grounding point 304, the plasma density reaches the maximum, and thus, along the circuit of the resonance coil 412, as it gradually moves away in the inner circumferential direction of the processing container 203, the plasma density rapidly decreases, resulting in the above-mentioned distribution of the plasma density. In addition, regarding the ICP generated near the midpoint, the distribution of the plasma density is formed to be substantially uniform along the entire inner circumferential direction of the processing container 203. Since the regions with a high plasma density form a continuous loop along the inner circumference of the processing container 203, it is speculated that this is one of the reasons for promoting the formation of the ICP along the entire inner circumferential direction of the processing container 203.

[0074] That is, in the case of using the resonance coil 412 of the comparative example, the grounding point of the resonance coil 412 is a singular point, and due to the plasma generated by the induced current at the grounding point, the distribution of the plasma density in the circumferential direction of the processing container 203 may be biased, resulting in a decrease in the in-plane uniformity of the film formed on the wafer 200. Regarding these, the winding diameter of the resonance coil is large relative to the wavelength of the high-frequency power, resulting in non-uniform plasma density in the circumferential direction, which is cited as one of the important factors. In particular, it was confirmed that when the value of the high-frequency power supplied from the high-frequency power supply 273 is set to 3500 to 4800 W, the deterioration of the in-plane uniformity becomes significant.

[0075] <Winding diameter of the resonance coil according to an embodiment of the present disclosure>

[0076] Next, with reference to Figure 4 (A) of Figure 4 (B) of Figure 5 (A) of Figure 5 (B) of, a resonance coil 212 according to an embodiment of the present disclosure will be described.

[0077] Regarding the resonance coil 212 according to an embodiment of the present disclosure, as shown in Figure 4 (A) of Figure 4 (B) of, the winding diameter of the resonance coil 212 expands at the first grounding point 302 on the lower end side of the resonance coil 212 and is different in other intervals on the line between the first grounding point 302 and the resonance coil 212. That is, when the distance from the inner wall surface (inner circumferential surface) of the upper container 210 to the inner diameter side surface of the resonance coil 212 (the surface facing the side wall of the upper container 210, that is, the inner circumferential surface), that is, the coil interval distance from the inner circumference of the midpoint of the resonance coil 212 to the inner circumference of the processing container 203 is set to d1, the coil interval distance of the first grounding point 302 of the resonance coil 212 is set to d2 longer than d1. Here, the midpoint of the resonance coil 212 means the approximate center between the first grounding point 302 and the second grounding point 304 of the resonance coil 212.

[0078] Specifically, regarding the resonance coil 212, in the direction from the first grounding point 302 toward the second grounding point 304, the first winding interval, which is the interval until one turn is wound along the outer circumference of the processing container 203, is composed of a first interval with a constant coil interval distance of d1 and a second interval. The second interval is continuous with the first interval, includes the first grounding point 302, and has a coil interval distance longer than d1. In addition, regarding the resonance coil 212, in the first winding interval, the coil interval distance of the second interval including the first grounding point 302 is longer than the coil interval distance of the first interval. It is also configured that the length of the second interval is shorter than half of the first winding interval.

[0079] As Figure 5 shown in (A) of Figure 5 and (B) of

[0080] The coil spacing distance d2 of the first ground point 302 is longer than the coil spacing distance d1 in other intervals. That is, the resonance coil 212 is configured such that in the interval between the first ground point 302 and the second ground point 304, the coil spacing distance d2 of the first ground point 302 is the longest. In addition, the resonance coil 212 is configured such that in the first winding interval, the coil spacing distance d2 of the first ground point 302 is the longest. In this way, in the first winding interval, only the vicinity of the singularity, that is, the first ground point 302, is separated from the processing container 203, and other intervals are brought closer to a predetermined distance d1 from the processing container 203, thereby being able to reduce the deviation of the plasma density of the ICP formed in the processing chamber 201 and minimize the decrease in the plasma density, and suppressing the decrease in the production efficiency of the reactants.

[0081] In addition, the coil spacing distance of the second ground point 304 of the resonance coil 212 of one embodiment of the present disclosure is d1, and in the upper end side of the resonance coil 212, in the direction from the second ground point 304 toward the first ground point 302, the coil spacing distance in the interval until one turn around the outer periphery of the processing container 203, that is, the second winding interval, is constant and is d1. Thereby, in the vicinity of the second ground point 304, an ICP with a plasma density higher than that of the ICP generated in the vicinity of the first ground point 302 can be generated, and the production efficiency of the reactants of the reaction gas can be improved.

[0082] In addition, the length of the first winding section of the resonance coil 212 is configured to be longer than the length from the first ground point 302 where the amplitude of the standing wave of the current flowing through the resonance coil 212 reaches the maximum to the nearest position where the amplitude is less than a predetermined ratio with respect to the amplitude at the first ground point 302. That is, in the first winding section of the resonance coil 212, there is a position where the amplitude of the standing wave of the current flowing through the resonance coil 212 is less than a predetermined ratio with respect to the amplitude at the first ground point 302. Here, since there is a tendency that the plasma density is lower in the section where the amplitude of the standing wave of the current is smaller, there is a position in the first winding section where the amplitude of the standing wave of the current is less than a predetermined ratio with respect to the amplitude at the first ground point 302, and thus it is easy to occur a deviation of the plasma density with the first ground point 302 as a singular point. Therefore, by adopting the resonance coil 212 of the present disclosure, the deviation of the plasma density can be significantly improved. As a predetermined ratio at which such a deviation of the plasma density with the first ground point 302 as a singular point is likely to occur, for example, 80% can be exemplified. In addition, when the predetermined ratio exceeds 80%, the distribution of the plasma density of the ICP in the first winding section is substantially uniform, and it may not be possible to obtain the effect of improving the uniformity by using the technology of the present disclosure. Therefore, as a predetermined ratio at which the effect of sufficiently improving the uniformity by using the technology of the present disclosure can be obtained, it is preferably 80% or less.

[0083] In addition, the length of the first winding section of the resonance coil 212 is configured to be longer than the length from the first ground point 302 to the first position where the amplitude of the standing wave of the current flowing through the resonance coil 212 is the smallest (i.e., the first position where the amplitude of the standing wave of the voltage is the largest). As described above, when there is a position where the amplitude of the standing wave of the current is the smallest in the first winding section of the resonance coil 212, there are a point where the amplitude of the standing wave of the current at the first ground point 302 is the largest and a point where it is the smallest in the first winding section, and it is easy to occur a deviation of the plasma density. Therefore, by adopting the resonance coil 212 of the present disclosure, the deviation of the plasma density can be significantly improved.

[0084] As described above, in the resonance coil 212 of one embodiment of the present disclosure, a power supply point is also provided on the line of the resonance coil 212, high-frequency power is supplied from the high-frequency power supply 273, and standing waves of current and voltage having a length equivalent to, for example, one wavelength of the supplied high-frequency power are formed on the line of the resonance coil 212. Therefore, at the first ground point 302, the second ground point 304, and the midpoint of the resonance coil 212, the amplitude of the standing wave of the current reaches the maximum. That is, at the first ground point 302, the second ground point 304, and the midpoint of the resonance coil 212, the amplitude of the standing wave of the voltage is the smallest (ideally zero), and at the positions therebetween, the amplitude is the largest. In addition, in order to reduce the impedance of the resonance coil 212, the power supply point is provided near the ground point.

[0085] As described above, in one embodiment of the present disclosure, the winding diameter of the coil is set such that the coil interval distance of the first ground point 302 disposed near the wafer 200 is the longest within the first winding section of the resonance coil 212. Further, the winding diameter of the coil is set such that the coil interval distance of the first ground point 302 of the resonance coil 212 is the longest within the section between the first ground point 302 and the second ground point 304 of the resonance coil 212. In this embodiment, this maximum distance is set as d2. Specifically, in this embodiment, the winding diameter of the coil is set such that the coil interval distance of the first ground point 302 of the resonance coil 212 is d2, which is longer than d1. In one embodiment of the present disclosure, the winding diameter of the coil is set such that the coil interval distance of the ground point where the amplitude of the standing wave of the current is the maximum becomes the maximum distance in the entire section of the resonance coil 212.

[0086] Here, regarding the intensity of the high-frequency electromagnetic field formed by the resonance coil 212, this intensity is inversely proportional to the distance from the resonance coil 212. Therefore, by setting the coil interval distance of the first ground point 302 to d2, which is longer than d1, the intensity of the high-frequency electromagnetic field of the first ground point 302 disposed near the wafer 200 and affected by the amplitude of the current of the resonance coil 212 is reduced.

[0087] Therefore, since it is configured such that the coil interval distance of the first ground point 302 close to the processing substrate, i.e., the wafer 200, is the longest within the section between the first ground point 302 and the second ground point 304 of the resonance coil 212, the intensity of the high-frequency electromagnetic field formed near the first ground point 302 is reduced. Therefore, it is possible to suppress the deviation of the plasma density of the processing gas generated in the circumferential direction of the resonance coil 212.

[0088] Further, the second ground point 304 is farther from the processing substrate, i.e., the wafer 200, than the first ground point 302. Therefore, the influence of the deviation of the plasma density occurring due to the second ground point 304 being a singular point on the in-plane uniformity of the processing on the wafer 200 is smaller than that of the first ground point 302. Therefore, by setting the coil interval distance of the second ground point 304, which is far from the wafer 200 and has a smaller influence on the in-plane uniformity of the substrate processing, to a distance (e.g., d1) shorter than the coil interval distance d2 of the first ground point 302, a decrease in plasma density caused by increasing the coil interval distance of the second ground point 304 does not occur, and the generation efficiency of the reactants can be maintained. As a result, it is possible to reduce the circumferential deviation of the plasma density caused by the ground point, maintain the plasma processing efficiency, and improve the in-plane uniformity of the wafer 200.

[0089] In addition, the specific values of the coil spacing distances, i.e., d1 and d2, can be appropriately adjusted according to other conditions such as the magnitude of the high-frequency power supplied to the resonance coil 212, the thickness of the resonance coil 212, and the degree of uniformity of the plasma density required (especially in the circumferential direction of the upper container 210).

[0090] (Control unit)

[0091] The controller 221 as the control unit is configured to control the APC valve 242, the valve 243b, and the vacuum pump 246 through the signal line A, control the base lifting mechanism 268 through the signal line B, control the heater power adjustment mechanism 276 and the impedance variable mechanism 275 through the signal line C, control the gate valve 244 through the signal line D, control the RF sensor 272, the high-frequency power supply 273, and the matcher 274 through the signal line E, and control the MFCs 252a to 252c, the valves 253a to 253c, and the valve 243a through the signal line F.

[0092] As Figure 6 shown, the control unit (control unit), i.e., the controller 221, is composed of a computer and includes: a CPU (Central Processing Unit) 221a, a RAM (Random Access Memory) 221b, a storage device 221c, and an I / O port 221d.

[0093] The RAM 221b, the storage device 221c, and the I / O port 221d are configured to be able to perform data exchange with the CPU 221a via the internal bus 221e. An input / output device 225 is connected to the controller 221, which is composed of, for example, a touch panel and a display.

[0094] The storage device 221c is composed of, for example, a flash memory, an HDD (Hard Disk Drive), etc. In the storage device 221c, a control program for controlling the operation of the substrate processing apparatus, a program recipe for recording the steps or conditions of the substrate processing described later, etc. are stored in a readable manner. The process recipe is combined in such a way that the controller 221 executes each step in the substrate processing process described later to obtain a predetermined result, and functions as a program. Hereinafter, the program recipe, the control program, etc. will also be simply referred to as a program. In addition, in this specification, the meaning of "program" includes: the case of only referring to the program recipe alone, the case of only referring to the control program alone, or the case of referring to both of them. In addition, the RAM 221b is configured as a memory area (work area) and can temporarily hold programs or data read by the CPU 221a.

[0095] The I / O port 221d is connected to: the aforementioned MFCs 252a to 252c, valves 253a to 253c, 243a, 243b, gate valve 244, APC valve 242, vacuum pump 246, RF sensor 272, high-frequency power supply 273, matcher 274, susceptor lifting mechanism 268, impedance variable mechanism 275, heater power adjustment mechanism 276, etc.

[0096] The CPU 221a reads and executes a control program from the storage device 221c, and is configured to read a process recipe from the storage device 221c according to an operation instruction input from the input / output device 225. In addition, the CPU 221a is configured to control the opening adjustment operation of the APC valve 242, the opening and closing operation of the valve 243b, and the start and stop of the vacuum pump 246 through the I / O port 221d and the signal line A according to the content of the read process recipe, control the lifting operation of the susceptor lifting mechanism 268 through the signal line B, control the power supply amount adjustment operation (temperature adjustment operation) to the heater 217b based on the heater power adjustment mechanism 276 and the impedance value adjustment operation based on the impedance variable mechanism 275 through the signal line C, control the opening and closing operation of the gate valve 244 through the signal line D, control the operations of the RF sensor 272, matcher 274 and high-frequency power supply 273 through the signal line E, and control the flow rate adjustment operations of various process gases based on the MFCs 252a to 252c and the opening and closing operations of the valves 253a to 253c, 243a through the signal line F, etc.

[0097] The controller 221 can be constituted by installing the aforementioned program stored in an external storage device (such as a magnetic disk such as a tape, floppy disk or hard disk, an optical disk such as a CD or DVD, an optical magnetic disk such as an MO, a semiconductor memory such as a USB memory or memory card) 226 in a computer. The storage device 221c and the external storage device 226 are configured as storage media capable of being read by a computer. Hereinafter, they will also be simply collectively referred to as storage media. In this specification, the meaning of "storage medium" includes: the case of only the storage device 221c alone, the case of only the external storage device 226 alone, or the case of both. In addition, the provision of the program to the computer may be performed not using the external storage device 226 but by using communication means such as the Internet or a dedicated line.

[0098] (2) Substrate processing process

[0099] Next, mainly with reference to Figure 7 the substrate processing process of one embodiment of the present disclosure will be described. Figure 7FIG. 0 is a flowchart showing a substrate processing step according to an aspect of the present disclosure. Regarding the substrate processing step according to an aspect of the present disclosure, for example, it is a step in a manufacturing process of a semiconductor device such as a flash memory, and is performed by the above-described substrate processing apparatus 100. In the following description, the operations of the respective parts constituting the substrate processing apparatus 100 are controlled by the controller 221.

[0100] In addition, although not shown in the figure, on the surface of the wafer 200 processed by the substrate processing step according to an aspect of the present disclosure, grooves having uneven portions with a high aspect ratio are formed in advance. In one aspect of the present disclosure, for example, a silicon (Si) layer exposed on the inner wall of the groove is subjected to an oxidation treatment as a plasma treatment.

[0101] (Substrate loading step S110)

[0102] First, the above-described wafer 200 is loaded into the processing chamber 201. Specifically, the base lifting mechanism 268 lowers the base 217 to the transfer position of the wafer 200, and causes the wafer top pin 266 to pass through the through hole 217a of the base 217. As a result, the wafer top pin 266 is in a state of protruding from the surface of the base 217 by a predetermined height.

[0103] Next, the gate valve 244 is opened, and the wafer 200 is loaded into the processing chamber 201 from the vacuum transfer chamber adjacent to the processing chamber 201 by a wafer transfer mechanism (not shown). The loaded wafer 200 is supported in a horizontal posture on the wafer top pin 266 protruding from the surface of the base 217. After the wafer 200 is loaded into the processing chamber 201, the wafer transfer mechanism is retracted outside the processing chamber 201, the gate valve 244 is closed to seal the inside of the processing chamber 201. Then, the base lifting mechanism 268 raises the base 217, thereby supporting the wafer 200 on the upper surface of the base 217.

[0104] (Heating / vacuum evacuation step S120)

[0105] Next, the wafer 200 loaded into the processing chamber 201 is heated. The heater 217b has been preheated, and the wafer 200 is held on the base 217 in which the heater 217b is embedded, thereby heating the wafer 200 to a predetermined value within a range of, for example, 150 to 750°C. In addition, during the heating of the wafer 200, the inside of the processing chamber 201 is evacuated by the vacuum pump 246 via the gas discharge pipe 231, and the pressure inside the processing chamber 201 is set to a predetermined value. The vacuum pump 246 operates at least until the substrate unloading step S160 described later is completed.

[0106] (Reaction gas supply step S13)

[0107] Next, as reaction gases, an oxygen-containing gas and a hydrogen-containing gas are started to be supplied. Specifically, valves 253a and 253b are opened, flow rate control is performed using MFCs 252a and 252b, and an oxygen-containing gas and a hydrogen-containing gas are started to be supplied into the processing chamber 201. At this time, the flow rate of the oxygen-containing gas is set to a predetermined value within a range of, for example, 20 to 2000 sccm. In addition, the flow rate of the hydrogen-containing gas is set to a predetermined value within a range of, for example, 20 to 1000 sccm.

[0108] In addition, the opening degree of the APC valve 242 is adjusted to control the exhaust in the processing chamber 201 so that the pressure in the processing chamber 201 becomes a predetermined pressure within a range of, for example, 1 to 250 Pa. In this way, the processing chamber 201 is appropriately exhausted, and the supply of the oxygen-containing gas and the hydrogen-containing gas is continued until the plasma processing step S140 described later ends.

[0109] As the oxygen-containing gas, for example, oxygen (O2), nitrous oxide (N2O) gas, nitric oxide (NO) gas, nitrogen dioxide (NO2) gas, ozone (O3) gas, water vapor (H2O gas), carbon monoxide (CO) gas, carbon dioxide (CO2) gas, etc. can be used. As the oxygen-containing gas, one or more of these can be used.

[0110] In addition, as the hydrogen-containing gas, for example, hydrogen (H2), deuterium (D2) gas, H2O gas, ammonia (NH3) gas, etc. can be used. As the hydrogen-containing gas, one or more of these can be used.

[0111] In addition, when using H2O gas as the oxygen-containing gas, it is preferable to use a gas other than H2O gas as the hydrogen-containing gas, and when using H2O gas as the hydrogen-containing gas, it is preferable to use a gas other than H2O gas as the oxygen-containing gas.

[0112] As the inert gas, for example, nitrogen (N2) can be used. In addition, rare gases such as argon (Ar), helium (He), neon (Ne), and xenon (Xe) can also be used. As the inert gas, one or more of these can be used.

[0113] (Plasma processing step S140)

[0114] When the pressure in the processing chamber 201 stabilizes, high-frequency power is started to be applied to the resonance coil 212 from the high-frequency power supply 273 via the RF sensor 272.

[0115] Accordingly, a high-frequency electromagnetic field is formed in the plasma generation space supplied with an oxygen-containing gas and a hydrogen-containing gas. The electromagnetic field can be used to excite a ring-shaped ICP with the highest plasma density at a height position corresponding to the electrical midpoint of the resonance coil 212 in the plasma generation space. In addition, an ICP is excited at the height position of the lower end of the resonance coil 212 as described above. The ICP is adjusted such that the distribution of the plasma density in the inner circumferential direction of the processing container 203 is made uniform by adjusting the coil spacing. In addition, although an ICP is also excited at the height position of the upper end of the resonance coil 212, in one embodiment of the present disclosure, unlike the lower end side, the distribution of the plasma density in the inner circumferential direction of the processing container 203 is not adjusted by adjusting the coil spacing. The plasma-like oxygen-containing gas and hydrogen-containing gas dissociate to generate reaction products such as oxygen-containing oxygen groups (oxygen active species) or oxygen ions, and hydrogen-containing hydrogen groups (hydrogen active species) or hydrogen ions.

[0116] In the substrate processing space, for the wafer 200 held on the susceptor 217, the groups generated by the inductive plasma and the ions in the un-accelerated state are uniformly supplied into the trenches. The supplied groups and ions react uniformly with the sidewalls to modify the surface layer (e.g., Si layer) into an oxide layer with good step coverage (e.g., Si oxide layer).

[0117] After that, when a predetermined processing time, for example, 10 to 300 seconds, has elapsed, the power output from the high-frequency power supply 273 is stopped, and the plasma discharge in the processing chamber 201 is stopped. In addition, the valves 253a and 253b are closed to stop supplying the oxygen-containing gas and the hydrogen-containing gas into the processing chamber 201. Through the above, the plasma processing step S140 ends.

[0118] (Vacuum evacuation step S150)

[0119] After stopping the supply of the oxygen-containing gas and the hydrogen-containing gas, the inside of the processing chamber 201 is evacuated through the gas discharge pipe 231. As a result, the oxygen-containing gas or hydrogen-containing gas in the processing chamber 201, the exhaust gas generated by the reaction of these gases, etc. are discharged to the outside of the processing chamber 201. After that, the opening degree of the APC valve 242 is adjusted to adjust the pressure in the processing chamber 201 to the same pressure as that of the vacuum transfer chamber (the destination for unloading the wafer 200, not shown) adjacent to the processing chamber 201.

[0120] (Substrate unloading step S160)

[0121] When the inside of the processing chamber 201 reaches a predetermined pressure, the susceptor 217 is lowered to the transfer position of the wafer 200, and the wafer 200 is supported on the wafer top pins 266. Then, the gate valve 244 is opened, and the wafer 200 is unloaded from the processing chamber 201 using the wafer transfer mechanism.

[0122] In this way, the substrate processing step of one embodiment of the present disclosure is completed.

[0123] (3) Variation

[0124] The resonant coil 212 of the above-described embodiment can be modified as shown in the following variations. Unless otherwise specified, the structure of each variation is the same as that of the above-described embodiment, and the description thereof is omitted.

[0125] (Variation 1)

[0126] In Variation 1, as shown in (A) of Figure 8 and (B) of Figure 8 , in addition to the first grounding point 302 on the lower end side of the resonant coil 212, the coil interval distance of the second grounding point 304 on the upper end side of the resonant coil 212 is made longer than the coil interval distance d1 at the midpoint of the resonant coil 212.

[0127] Specifically, with respect to the resonant coil 212, in the direction from the second grounding point 304 toward the first grounding point 302, the second winding interval, which is the interval until one turn is wound around the outer periphery of the processing container 203, is composed of a third interval with a constant coil interval distance d3 and a fourth interval. The fourth interval is continuous with the third interval, includes the second grounding point 304, and has a coil interval distance longer than d3. In addition, the resonant coil 212 is configured such that in the second winding interval, the coil interval distance of the fourth interval including the second grounding point 304 is longer than the coil interval distance d3 of the third interval. It is also configured such that the length of the fourth interval is shorter than half of the second winding interval.

[0128] As shown in (A) of Figure 8 and (B) of Figure 8 , it is configured such that the coil interval distance d4 of the second grounding point 304 in the fourth interval is longer than the coil interval distance d3 of the third interval. In addition, the resonant coil 212 is configured such that among the coil interval distances in the second winding interval, the coil interval distance d4 of the second grounding point 304 is the longest. In this way, similarly to the first winding interval, in the second winding interval, only the vicinity of the second grounding point 304, which is the specific point, is moved away from the processing container 203, and other intervals are brought closer to a predetermined distance d3 from the processing container 203, thereby being able to reduce the deviation of the plasma density of the ICP formed in the processing chamber 201 and minimize the reduction of the plasma density, and suppressing the reduction of the production efficiency of the reactants.

[0129] In this modified example, it is set that at the grounding points of the resonance coil 212, that is, at the first grounding point 302 of the resonance coil 212 where the amplitude of the standing wave of the current is the largest, and at the second grounding point 304 of the resonance coil 212 where the amplitude of the standing wave of the current is the largest, the coil pitch distance is longer than that in other intervals of the resonance coil 212. Thus, even when the amplitude of the standing wave of the current is the largest at the grounding points at both ends of the first grounding point 302 and the second grounding point 304 of the resonance coil 212, according to this modified example, it is possible to reduce the deviation of the plasma density and improve the in-plane uniformity of the wafer 200.

[0130] That is, it is configured such that in addition to the first grounding point 302 of the resonance coil 212, the coil pitch distance of the second grounding point 304 is longer than that in other intervals between the first grounding point 302 and the second grounding point 304, thereby reducing the intensity of the high-frequency electromagnetic field formed near the first grounding point 302 and the second grounding point 304.

[0131] In addition, the coil pitch distance d4 of the second grounding point 304 and the coil pitch distance d2 of the first grounding point 302 in the second interval may be equal, or may be different. In this modified example, it is configured such that it is different from the coil pitch distance d2 of the first grounding point 302, and the coil pitch distance d2 of the first grounding point 302 is longer than the coil pitch distance d4 of the second grounding point 304. In addition, d3 and d1 may also be the same distance.

[0132] As described above, the second grounding point 304 is farther from the processing substrate, that is, the wafer 200, than the first grounding point 302. Therefore, the influence of the deviation of the plasma density caused by the second grounding point 304 being a singular point on the in-plane uniformity of the processing on the wafer 200 is smaller than that of the first grounding point 302. Therefore, by making the coil pitch distance d4 of the second grounding point 304, which is far from the wafer 200 and has a relatively small influence on the in-plane uniformity of the substrate processing, shorter than the coil pitch distance d2 of the first grounding point 302, the decrease in the plasma density caused by increasing the coil pitch distance of the second grounding point 304 is minimized, and the generation efficiency of the reactants can be maintained. As a result, it is possible to reduce the circumferential deviation of the plasma density caused by the grounding points, maintain the plasma processing efficiency, and improve the in-plane uniformity of the wafer 200.

[0133] In addition, by setting the coil pitch distance d2 of the first grounding point 302 and the coil pitch distance d4 of the second grounding point 304 to be different, it is possible to separately adjust the plasma density distribution in the first winding interval and the plasma density distribution in the second winding interval, and control the film thickness distribution of the film formed on the wafer 200.

[0134] As described above, there is a tendency here that, compared with the plasmas generated on the upper and lower sides of the resonance coil 212, the plasma generated near the midpoint has more excellent uniformity in the circumferential density of the upper container 210. Therefore, in this modification example, the coil interval distances of the grounding points on the upper and lower sides of the resonance coil 212 are increased, the intensity of the high-frequency electromagnetic field generated from these positions in the upper container 210 is reduced, and the contribution ratio of the plasma with excellent uniformity generated near the midpoint to the substrate processing is relatively increased. Therefore, from the viewpoint of improving the uniformity of the circumferential plasma density of the upper container 210, generally speaking, this modification example is more preferable than the above-described manner. However, from the viewpoint of emphasizing the production efficiency of the reactants, the above-described manner in which the intensity of the high-frequency electromagnetic field in the upper container 210 generated from the grounding point on the upper side of the resonance coil 212 is not reduced and is used for the production of the reactants is preferable.

[0135] (Modification Example 2)

[0136] In Modification Example 2, as Figure 9 shown in (A) of Figure 9 and (B) of Figure 9 it is configured such that the coil interval distance of the first winding section on the lower side of the resonance coil 212 is longer than the coil interval distance d1 at the midpoint of the resonance coil 212, and the coil interval distance of the second winding section including the second grounding point 304 on the upper side of the resonance coil 212 is the same d1 as the coil interval distance at the midpoint of the resonance coil 212. In addition, as

[0137] shown in (B) of

[0138] Figure 9 it is also possible that the coil interval distance at the starting point on the upper side of the first winding section is, for example, d1, or may be longer than d1.

[0137] In this modification example, the first winding section is composed of a sixth section including the first grounding point 302 and a fifth section which is the section other than the sixth section. In the fifth section, it is configured such that the coil interval distance continuously increases from the coil interval distance d1 to d5 in the direction from the second grounding point 304 toward the first grounding point 302, and in the sixth section, it is configured such that the coil interval distance further continuously increases from d5, which is longer than the coil interval distance d1, to d2 in the direction toward the first grounding point 302. The coil interval distance d2 of the first grounding point 302 is configured to be the longest among the coil interval distances in the first winding section. In addition, the resonance coil 212 is configured such that the increasing rate of the coil interval distance in the direction from the second grounding point 304 toward the first grounding point 302 in the sixth section is larger than the increasing rate in the fifth section. That is, the resonance coil 212 is configured such that the increase amount of the coil interval distance in the vicinity section of the first grounding point 302, i.e., the sixth section, changes in a manner larger than the increase amount in the fifth section.

[0138] By configuring the resonance coil 212 in this way, it is also possible to increase the coil interval distance on the lower end side as in the above-described embodiment, reduce the intensity of the high-frequency electromagnetic field generated near the ground point near the wafer 200 inside the upper container 210, and improve the uniformity of the plasma density in the circumferential direction of the upper container 210.

[0139] (Modification Example 3)

[0140] In Modification Example 3, as Figure 10 shown, in addition to the coil interval distance of the first winding section of the resonance coil 212 including the first ground point 302 in the above Modification Example 2, the coil interval distance of the entire second winding section of the resonance coil 212 including the second ground point 304 is made longer than the coil interval distance of other sections between the first ground point 302 and the second ground point 304 of the resonance coil 212, that is, the coil interval distance d1 at the midpoint of the resonance coil 212. Further, in this modification example, the coil interval distance of the second winding section of the resonance coil 212 including the second ground point 304 is d6 and is configured to be constant. In this modification example, it is configured such that the coil interval distances of both the entire first winding section and the entire second winding section of the resonance coil 212 are longer than the coil interval distance of other sections between the first ground point 302 and the second ground point 304 of the resonance coil 212, that is, the coil interval distance d1 at the midpoint of the resonance coil 212. By configuring in this way, it is possible to maintain the plasma density (i.e., the generation efficiency of the reactants) generated by other sections between the first ground point 302 and the second ground point 304 of the resonance coil 212. The first ground point 302 and the second ground point 304 are singular points, and it is possible to more effectively suppress the deviation of the plasma density compared to the above-described embodiment or Modification Examples 1 and 2.

[0141] Further, the coil interval distance d6 is at least longer than d1, and preferably longer than the coil interval distance d4 in Modification Example 2. The coil interval distance d6 is longer than d4 and is preferably a length such that ICP is not substantially generated by the high-frequency electromagnetic field generated by the second winding section. Thereby, it is possible to more effectively suppress the deviation of the plasma density due to the second ground point 304 being a singular point.

[0142] In addition, in this modification example, a structure in which the coil pitch distances in both the first winding section and the second winding section of the resonance coil 212 are longer than those in other sections has been described. However, it is not limited to this, and it may also be configured such that the coil pitch distance in either the first winding section or the second winding section is longer than that in other sections. That is, it may also be configured such that the coil pitch distance in at least one of the entire first winding section and the entire second winding section of the resonance coil 212 is longer than the coil pitch distance d1 in other sections between the first grounding point 302 and the second grounding point 304 of the resonance coil 212.

[0143] In addition, in this modification example, a structure in which the coil pitch distance in the first winding section is in the manner of Modification Example 2 and the coil pitch distance in the second winding section is d6 and constant has been described. However, it is not limited to this, and the first winding section may also be configured in the same manner as the second winding section such that the coil pitch distance of the entire first winding section is a distance (e.g., d6) longer than d1 and constant.

[0144] (Modification Example 4)

[0145] In Modification Example 4, as Figure 11 shown, it is configured such that the coil pitch distances in the first winding section and the second winding section are longer than the coil pitch distance in other sections between the first grounding point 302 and the second grounding point 304, that is, the coil pitch distance d1 at the midpoint of the resonance coil 212. In addition, between the ranges respectively facing the midpoint from the first winding section and the second winding section, it is configured such that the coil pitch distance gradually becomes shorter, and at the midpoint between the first grounding point 302 and the second grounding point 304, the coil pitch distance is the shortest. In addition, it may also be configured such that the coil pitch distance gradually becomes shorter between the range facing the midpoint from either the first winding section or the second winding section. The coil pitch distances in the first winding section and the second winding section may be the same as the coil pitch distances in Modification Example 3, for example.

[0146] By configuring the resonance coil 212 in this way, especially by selectively generating the ICP at the midpoint of the resonance coil 212 with excellent uniformity of plasma density and production efficiency of reactants, and making the coil interval distance between the first grounding point 302 and the second grounding point 304, which is the specific point that reduces the uniformity of plasma density, the largest, the in-plane uniformity of the wafer 200 for plasma processing can be further improved. In addition, standing waves of voltage are generated respectively in the interval between the first winding section and the midpoint of the resonance coil 212 and in the interval between the second winding section and the midpoint of the resonance coil 212. Plasma of the CCP (Capacitively Coupled Plasma) component (hereinafter referred to as CCP) formed near the interval where the amplitude of the standing wave of this voltage is large may generate a sputtering ring with respect to the inner wall surface of the processing container 203. However, by configuring the resonance coil 212 in such a way that the coil interval distance in the interval where the amplitude of the standing wave of this voltage is large is larger than d1 as in this modification example, the generation of CCP can be suppressed, and the sputtering ring caused by CCP can be suppressed.

[0147] <Other methods>

[0148] The above has described various typical embodiments and modification examples of the present disclosure. However, the present disclosure is not limited to these embodiments and can also be used in appropriate combinations.

[0149] For example, in the above method, an example in which the upper end and the lower end of the resonance coil 212 are grounded respectively to set the first grounding point 302 and the second grounding point 304 has been described. However, it is not limited to this, and a grounding point may not be provided at the upper end or the lower end of the resonance coil 212. That is, the resonance coil 212 may also include an interval other than the interval between the first grounding point 302 and the second grounding point 304. At this time, it is preferable to further ground at least one of the upper end or the lower end of the interval other than the interval between the first grounding point 302 and the second grounding point 304. By grounding the end of the interval other than the interval between the first grounding point 302 and the second grounding point 304 in this way, the influence of the changes in current and voltage in the interval from the first grounding point 302 or the second grounding point 304 to these ends on the plasma density distribution can be suppressed, and the control of the plasma density distribution can be easily performed.

[0150] In addition, in the above method, an example of oxidizing the substrate surface using plasma was described. However, in addition to this, it can also be applied to nitriding treatment using a nitrogen-containing gas as the treatment gas. Furthermore, it is not limited to nitriding treatment or oxidizing treatment, but can be applied to various techniques for treating the substrate using plasma. For example, it can be applied to: modification treatment or doping treatment of a film formed on the substrate surface using plasma, reduction treatment of an oxide film, etching treatment of the film, ashing treatment of a resist, etc.

[0151] In addition, although specific embodiments and variations of the present disclosure have been specifically described, the present disclosure is not limited to these embodiments and variations, and those skilled in the art can implement various other embodiments within the scope of the present disclosure.

[0152] Examples will be described below.

[0153] Example 1

[0154] A bare wafer (Si substrate), i.e., Sample 1 and Sample 2, were prepared, and the following oxidation treatments were performed on Sample 1 and Sample 2, respectively.

[0155] Regarding Sample 1, in the above-described substrate processing apparatus 100, the resonance coil 212 shown in (A) of Figure 8 and Figure 8 of (B) was used, and the surface of the bare wafer was oxidized according to the above-described Figure 7 substrate processing sequence to form an oxide film on the bare wafer. That is, high-frequency power was supplied to the resonance coil 212 to plasma-excite an oxygen-containing gas and a hydrogen-containing gas for oxidation treatment. The processing conditions were predetermined conditions within the range of the processing conditions described in the above method.

[0156] Regarding Sample 2, in the above-described substrate processing apparatus 100, the resonance coil 412 shown in (A) of Figure 3 and Figure 3 of (B) was used, and the surface of the bare wafer was oxidized according to the above-described Figure 7 substrate processing sequence to form an oxide film on the bare wafer. That is, high-frequency power was supplied to the resonance coil 412 to perform the same oxidation treatment as above. The processing conditions were predetermined conditions within the range of the processing conditions described in the above method, i.e., conditions common to the processing conditions of Sample 1.

[0157] Figure 12 is a graph showing a comparison of the average film thickness and in-plane uniformity of the oxide films formed on Sample 1 and Sample 2, respectively. Here, the in-plane uniformity is a value (%) calculated by dividing the difference between the maximum film thickness and the minimum film thickness by the average film thickness.

[0158] As Figure 12As shown, regarding the oxide film formed on the wafer of Sample 1 and the oxide film formed on the wafer of Sample 2, it was confirmed that the difference in the average film thickness was about 0.1 nm and the difference was small. The in-plane uniformity was improved for the oxide film formed on the wafer of Sample 1 compared to the oxide film formed on the wafer of Sample 2. That is, it was confirmed that by using the resonance coil 212 of the present embodiment, the in-plane uniformity of the wafer can be improved.

Claims

1. A substrate processing apparatus, characterized in that, Comprising: A processing chamber that plasma-excites a processing gas; A gas supply system that supplies the processing gas into the processing chamber; and A coil that is wound multiple times in a spiral along the outer periphery of the processing chamber in an interval between a first ground point and a second ground point, and is supplied with high-frequency power, The first ground point is provided below the second ground point, The coil is configured such that in a direction from the first ground point toward the second ground point, in an interval up to one turn along the outer periphery of the processing chamber, i.e., a first winding interval, a coil interval distance, which is the distance from the inner periphery of the coil to the inner periphery of the processing chamber in an interval including a part of the first ground point, is longer than the coil interval distances of other intervals continuous with the interval including the part of the first ground point, and there is no other interval where the coil is disposed between the first winding interval and the outer periphery of the processing chamber.

2. The substrate processing apparatus according to claim 1, wherein: The coil is configured such that in the first winding interval, the coil interval distance of the first ground point is the longest.

3. The substrate processing apparatus according to claim 1, wherein: The coil is configured such that in an interval between the first ground point and the second ground point, the coil interval distance of the first ground point is the longest.

4. The substrate processing apparatus according to claim 1, wherein: The length of the interval between the first ground point and the second ground point of the coil is n times or 1 / n times the wavelength of the high-frequency signal supplied as the high-frequency power, where n is a natural number.

5. The substrate processing apparatus according to claim 1, wherein: The first winding interval of the coil is composed of a first interval and a second interval. The coil interval distance of the first interval is a distance d, and the second interval includes the first ground point and the coil interval distance is longer than the distance d.

6. The substrate processing apparatus according to claim 5, wherein: The length of the second interval is shorter than half of the first winding interval.

7. The substrate processing apparatus according to claim 1, wherein: It further includes a substrate stage for placing a substrate, The substrate stage is disposed in the processing chamber and below the coil.

8. The substrate processing apparatus according to claim 1, wherein: The coil is configured such that in a direction from the second ground point toward the first ground point, in an interval up to one turn along the outer periphery of the processing chamber, i.e., a second winding interval, the coil interval distance of an interval including a part of the second ground point is longer than the coil interval distances of other intervals continuous with the interval including the part of the second ground point.

9. The substrate processing apparatus according to claim 8, wherein: The second winding interval of the coil is composed of a third interval and a fourth interval. The coil interval distance of the third interval is a distance d3, and the fourth interval includes the second ground point and the coil interval distance is longer than the distance d3.

10. The substrate processing apparatus according to claim 8, wherein: the coil spacing distance of the second grounding point is different from the coil spacing distance of the first grounding point.

11. The substrate processing apparatus according to claim 10, wherein: the coil spacing distance of the first grounding point is longer than the coil spacing distance of the second grounding point.

12. The substrate processing apparatus according to claim 1, wherein: the coil is configured such that in the direction from the second grounding point toward the first grounding point, the coil spacing distance is constant in the section where it winds around the outer circumference of the processing container once, i.e., in the second winding section.

13. The substrate processing apparatus according to claim 1, wherein: the length of the first winding section of the coil is longer than the following length, i.e., the length from the position where the amplitude of the standing wave of the current flowing through the coil is less than 80% of the amplitude at the first grounding point to the first grounding point.

14. The substrate processing apparatus according to claim 1, wherein: the length of the first winding section of the coil is longer than the following length, i.e., the length from the position where the amplitude of the standing wave of the current flowing through the coil is the minimum to the first grounding point.

15. The substrate processing apparatus according to claim 1, wherein: the coil is configured such that within the first winding section, the coil spacing distance increases in the direction from the second grounding point toward the first grounding point, and regarding the increasing rate of the coil spacing distance in the direction from the second grounding point toward the first grounding point, it is larger in the section including a part of the first grounding point than in other sections continuous with the section including a part of the first grounding point.

16. The substrate processing apparatus according to claim 1, wherein: the coil is configured such that the coil spacing distance of at least one of the entire first winding section and the entire section where it winds around the outer circumference of the processing container once in the direction from the second grounding point toward the first grounding point, i.e., the entire second winding section, is longer than the other sections of the coil between the first grounding point and the second grounding point except for the entire first winding section and the entire second winding section.

17. The substrate processing apparatus according to claim 16, wherein: the coil is configured such that at the midpoint between the first grounding point and the second grounding point, the coil spacing distance is the shortest, and in the range of the coil from at least one of the first winding section and the second winding section toward the midpoint, the coil spacing distance is shorter. ​ ​ ​ ​ ​ ​ The coil is configured such that, in the direction from the first ground point toward the second ground point, within the section up to one full turn around the outer periphery of the processing container, i.e., the first winding section, the coil spacing distance, which is the distance from the inner circumference of the coil to the inner circumference of the processing container in the section including a part of the first ground point, is longer than the coil spacing distances of other sections continuous with the section including a part of the first ground point, and there is no other section of the coil disposed between the first winding section and the outer periphery of the processing container. The process includes: (a) a process of loading a substrate into the processing container; (b) a process of supplying the processing gas into the processing container; (c) a process of supplying high-frequency power to the coil and plasma-exciting the processing gas supplied into the processing container; and (d) a process of supplying a reactant generated from the plasma-excited processing gas to the substrate and processing the substrate.

19. A substrate processing method, characterized in that: the following processes are performed in a substrate processing apparatus, the substrate processing apparatus includes: a processing container that plasma-excites a processing gas; and a coil, the section between a first ground point and a second ground point of which is wound in a spiral shape around the outer periphery of the processing container for multiple turns, the first ground point is disposed below the second ground point, the coil is configured such that, in the direction from the first ground point toward the second ground point, within the section up to one full turn around the outer periphery of the processing container, i.e., the first winding section, the coil spacing distance, which is the distance from the inner circumference of the coil to the inner circumference of the processing container in the section including a part of the first ground point, is longer than the coil spacing distances of other sections continuous with the section including a part of the first ground point, and there is no other section of the coil disposed between the first winding section and the outer periphery of the processing container. The process includes: (a) a process of loading a substrate into the processing container; (b) a process of supplying the processing gas into the processing container; (c) a process of supplying high-frequency power to the coil and plasma-exciting the processing gas supplied into the processing container; and (d) a process of supplying a reactant generated from the plasma-excited processing gas to the substrate and processing the substrate.

20. A storage medium readable by a computer, characterized in that: it stores a program for causing a substrate processing apparatus to perform the following steps by a computer, the substrate processing apparatus includes: a processing container that plasma-excites a processing gas; and a coil, the section between a first ground point and a second ground point of which is wound in a spiral shape around the outer periphery of the processing container for multiple turns, the first ground point is disposed below the second ground point, The coil is configured such that, in the direction from the first ground point toward the second ground point, within the interval up to one round of winding along the outer periphery of the processing container, i.e., the first winding interval, the coil interval distance, which is the distance from the inner periphery of the coil to the inner periphery of the processing container in the interval including a part of the first ground point, is longer than the coil interval distance in other intervals continuous with the interval including a part of the first ground point, and no other intervals of the coil are arranged between the first winding interval and the outer periphery of the processing container. The steps include: (a) a step of loading a substrate into the processing container; (b) a step of supplying the processing gas into the processing container; (c) a step of supplying high-frequency power to the coil and performing plasma excitation on the processing gas supplied into the processing container; and (d) a step of supplying a reactant generated from the processing gas subjected to plasma excitation to the substrate and processing the substrate.

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