Substrate processing apparatus

Abstract

In a substrate processing apparatus, a gas is supplied between a lower surface (92) of a substrate (9) and a base surface (210) of a base portion (21), a gas flow (93) toward a radial outside is formed, and a pressure drop is generated in a space between the substrate (9) and the base portion (21) by a Bernoulli effect. A second surface (212) of the base surface (210) faces upward as it goes toward the radial outside. A third surface (213) faces downward as it goes toward the radial outside from an outer periphery of the second surface (212). A fourth surface (214) is a circular ring-shaped surface that is continuous with a lower end edge of the third surface (213). The fourth surface (214) extends radially outward further than an outer periphery of the substrate (9). Thus, the attachment of a processing liquid to the lower surface (92) of the substrate (9) can be suppressed, and the stability of the holding of the substrate (9) can be improved.

Description

Technical Field

[0001] This invention relates to a substrate processing apparatus for processing substrates.

[0002] [Reference to relevant applications]

[0003] This application claims the benefit of priority to Japanese Patent Application No. JP2022-047869, filed on March 24, 2022, the entire invention of which is incorporated herein. Background Technology

[0004] In the past, various treatments were performed on the substrate during the manufacturing process of semiconductor substrates (hereinafter referred to as "substrate"). For example, the substrate, which is held horizontally in a substrate holding section, is rotated, and a treatment liquid is supplied to the surface of the rotating substrate, thereby performing liquid treatment on the substrate.

[0005] In the wet etching apparatus disclosed in Japanese Patent Application Publication No. 2009-142818 (Document 1), a Bernoulli chuck is used as the substrate holding part to hold the substrate. High-pressure gas is supplied between the substrate and a support located below the substrate, and the substrate is attracted to the support by the negative pressure of the gas flowing along the lower surface of the substrate. The gas is supplied to the space between the substrate and the support from an annular nozzle formed on the upper surface of the support below the outer periphery of the substrate. An annular gas discharge part is provided on the support, extending radially outward from the annular nozzle and exiting downward from the substrate. Below the gas discharge part, an annular gas discharge path is provided, extending radially outward and downward from the annular nozzle.

[0006] In the wet etching apparatus, the etchant supplied to the upper surface of the substrate flows back from the outer periphery of the substrate to the lower surface, filling the gap between the periphery of the lower surface of the substrate and the upper surface of the gas exhaust section of the support. This etches the periphery of the lower surface of the substrate. The etchant flowing back to the lower surface of the substrate is discharged radially outward via the gas exhaust path. Furthermore, the gas supplied from the annular nozzle between the substrate and the support is also discharged radially outward via the same gas exhaust path.

[0007] However, in liquid processing of the substrate, there are also cases where the etching process differs from that in Document 1, and it is necessary to prevent the processing liquid supplied to the upper surface of the substrate from flowing back to the lower surface of the substrate. However, when the substrate is held by a Bernoulli chuck as in Patent Document 1, there is a concern that the processing liquid supplied to the upper surface of the substrate and flowing down from the outer periphery of the substrate may be attracted by the negative pressure generated between the substrate and the support, and flow back to the lower surface of the substrate.

[0008] On the other hand, if the flow rate of the gas supplied between the substrate and the support is to be increased to prevent the processing liquid from flowing back to the lower surface of the substrate, then the gas pushes the substrate upwards, and there is a concern that the stability of the substrate held by the Bernoulli chuck may be reduced. Summary of the Invention

[0009] The present invention focuses on a substrate processing apparatus for processing substrates, with the aim of suppressing the adhesion of processing liquid to the lower surface of the substrate and improving the stability of substrate retention.

[0010] A preferred embodiment of the substrate processing apparatus of the present invention includes: a substrate holding section for holding a substrate in a horizontal state; a substrate rotating mechanism for rotating the substrate holding section about a central axis in the vertical direction; and a processing liquid supply section for supplying processing liquid to the upper surface of the substrate. The substrate holding section includes: a base section having a base surface facing the lower surface of the substrate and extending radially outward from the outer periphery of the substrate; a plurality of support pins arranged circumferentially on the base surface and protruding upward from the base surface, contacting the outer periphery of the lower surface of the substrate; and a gas supply section for supplying gas between the lower surface of the substrate and the base surface of the base section, forming an airflow in the radially outward direction, thereby generating a pressure drop in the space between the substrate and the base section through the Bernoulli effect. The base surface includes: a first surface, a horizontal circular surface facing the center of the substrate in the vertical direction; a second surface, an annular surface extending radially outward from the outer periphery of the first surface below the substrate, facing upward as it moves radially outward, and for which the plurality of support pins are disposed; a third surface, an annular surface continuous with the outer periphery of the second surface below the lower surface of the substrate, extending vertically downward from the outer periphery of the second surface, or facing downward as it moves radially outward; and a fourth surface, an annular surface continuous with the lower edge of the third surface, extending radially outward further radially outward than the outer periphery of the substrate. The gas supply section includes a circumferential gas outlet disposed at the boundary between the first surface and the second surface, or on the first surface, for discharging gas radially outward.

[0011] According to the substrate processing apparatus, the processing liquid can be suppressed from adhering to the lower surface of the substrate, and the stability of the substrate can be improved.

[0012] Preferably, the fourth surface extends in the same position as the lower edge of the third surface in the vertical direction, or faces downward as it moves radially outward from the lower edge of the third surface.

[0013] Preferably, the base surface also has a fifth annular surface that faces downwards from the outer periphery of the fourth surface toward the radially outward side.

[0014] Preferably, the third surface is a curved surface that bulges downward and radially outward and upward from the outer periphery of the second surface.

[0015] Preferably, the third surface is continuous with the outer periphery of the second surface below the substrate.

[0016] Preferably, the radial distance between the boundary between the second surface and the third surface and the outer periphery of the substrate is 0.5 mm or more and 2.0 mm or less.

[0017] Preferably, the vertical distance between the boundary between the second and third surfaces and the lower surface of the substrate is 0.6 mm or more and 1.0 mm or less.

[0018] Preferably, the second surface is an inclined surface that extends radially outward and upward from the outer periphery of the first surface at a specific inclination angle, and the inclination angle of the second surface is 15° or less.

[0019] Preferably, the radial length of the second surface is 10 mm or more.

[0020] Preferably, the vertical distance between the first surface and the lower surface of the substrate is 0.6 mm or more and 1.5 mm or less.

[0021] The stated purpose, as well as other purposes, features, forms, and advantages, will become clear from the following detailed description of the invention with reference to the accompanying drawings. Attached Figure Description

[0022] Figure 1 This is a top view showing a substrate processing system according to one embodiment.

[0023] Figure 2 This is a side view showing the configuration of the substrate processing apparatus.

[0024] Figure 3 This is a top view showing the substrate holding section.

[0025] Figure 4 It is a cross-sectional view showing a portion of the substrate holding section.

[0026] Figure 5 This is a cross-sectional view showing the outer periphery of the substrate holding section.

[0027] Figure 6 This is a cross-sectional view showing the outer periphery of the substrate holding section.

[0028] Figure 7A This is a diagram showing the flow of gas near the outer periphery of the substrate.

[0029] Figure 7BThis is a diagram showing the flow of gas near the outer periphery of the substrate.

[0030] Figure 7C This is a diagram showing the flow of gas near the outer periphery of the substrate.

[0031] Figure 8A This is a diagram showing the flow of gas near the outer periphery of the substrate.

[0032] Figure 8B This is a diagram showing the flow of gas near the outer periphery of the substrate.

[0033] Figure 8C This is a diagram showing the flow of gas near the outer periphery of the substrate. Detailed Implementation

[0034] Figure 1 This is a schematic top view showing the layout of a substrate processing system 10 equipped with a substrate processing apparatus according to an embodiment of the present invention. The substrate processing system 10 is a system for processing a semiconductor substrate 9 (hereinafter simply referred to as "substrate 9"). The substrate processing system 10 includes a transport block 101 and a processing block 102 combined with the transport block 101.

[0035] The transfer block 101 includes a carrier holding section 104, a transfer robot 105, and an IR moving mechanism 106. The carrier holding section 104 holds multiple carriers 107 capable of accommodating multiple substrates 9. The multiple carriers 107 (e.g., FOUP (Front Opening Unified Pod)) are held in the carrier holding section 104 in a state arranged in a specific carrier arrangement direction. The IR moving mechanism 106 moves the transfer robot 105 in the carrier arrangement direction. The transfer robot 105 performs a removal action to take the substrate 9 out of the carrier 107 and a placement action to place the substrate 9 into the carrier 107 held in the carrier holding section 104. The substrate 9 is transported by the transfer robot 105 in a horizontal posture.

[0036] Processing block 102 includes multiple (e.g., four or more) processing units 108 for processing substrate 9 and a central robot 109. The multiple processing units 108 are arranged to surround the central robot 109 when viewed from above. Various processes on the substrate 9 are performed in the multiple processing units 108. The substrate processing apparatus described later is one of the multiple processing units 108. The central robot 109 performs actions to move the substrate 9 into the processing unit 108 and to move the substrate 9 out of the processing unit 108. Furthermore, the central robot 109 transports the substrate 9 between the multiple processing units 108. The substrate 9 is transported by the central robot 109 in a horizontal orientation. The central robot 109 receives the substrate 9 from the transfer robot 105 and transfers the substrate 9 to the transfer robot 105.

[0037] Figure 2 This is a side view showing the configuration of substrate processing apparatus 1. Figure 2 The image shows a portion of the substrate processing apparatus 1 in cross-section. The substrate processing apparatus 1 is a monolithic device for processing substrates 9 piece by piece. The substrate processing apparatus 1 supplies a processing liquid to the substrates 9 for liquid processing. In this liquid processing, for example, in a process prior to being introduced into the substrate processing apparatus 1, foreign matter adhering to the substrates 9 is removed (e.g., cleaning). This foreign matter is, for example, residue remaining on the surface of the substrates 9 during the grinding process. In the following description, [the following will be used to describe this process]. Figure 2 The upper and lower sides are referred to as the "upper side" and "lower side".

[0038] The substrate processing apparatus 1 includes a substrate holding section 2, a substrate rotation mechanism 33, a cup section 4, a processing liquid supply section 51, a processing section moving mechanism 52, and a chamber 11. The substrate holding section 2, substrate rotation mechanism 33, cup section 4, and processing liquid supply section 51 are housed within the internal space of the chamber 11. An airflow forming section 12 is provided on the top cover of the chamber 11 to supply gas to the internal space, forming a downward-flowing airflow (so-called downflow). For example, an FFU (Fan Filter Unit) is used as the airflow forming section 12. Alternatively, an airflow forming section 12 other than an FFU may be provided in the substrate processing apparatus 1.

[0039] The substrate holding part 2 and the substrate rotating mechanism 33 are both parts of a rotating chuck that holds and rotates a generally circular substrate 9. The substrate holding part 2 holds the substrate 9 in a horizontal state from below. The substrate holding part 2 is a Bernoulli chuck that adsorbs and holds the substrate 9 based on the Bernoulli effect. The substrate 9 is, for example, a generally circular substrate with a diameter of 300 mm.

[0040] Figure 3 This is a top view showing the substrate holding section 2. Figure 4 The substrate holding part 2 is in Figure 3 A cross-sectional view cut off at position IV-IV. Figure 4 In the image, the substrate 9 held in the substrate holding section 2 is indicated by a dashed line. For example... Figure 3 and Figure 4 As shown, the substrate holding part 2 includes a base part 21, multiple support pins 22 and a gas supply part 23.

[0041] The base portion 21 is a generally circular plate-shaped component centered on a central axis J1 pointing vertically. The substrate 9 is disposed above the base portion 21, separate from it. The upper main surface 210 (hereinafter also referred to as "base surface 210") of the base portion 21 faces the lower surface 92 of the substrate 9 vertically, at a position that moves downward away from the lower main surface (hereinafter also referred to as "lower surface 92") of the substrate 9. The diameter of the base portion 21 is larger than the diameter of the substrate 9, and the base surface 210 extends radially outward along the entire circumference of the substrate 9.

[0042] Multiple support pins 22 are arranged separately on the base surface 210 of the base portion 21 in a circumferential direction (hereinafter referred to as "circumferential direction") centered on the central axis J1. The multiple support pins 22 are arranged on the same circumference centered on the central axis J1. For example, the multiple support pins 22 are arranged at approximately equal angular intervals in the circumferential direction. Figure 3 In the example shown, there are 30 support pins 22. Each support pin 22 is a protrusion projecting upward from the base surface 210. The shape of each support pin 22 is, for example, approximately hemispherical. The support pins 22 are fixed to the base portion 21 and do not move relative to the base portion 21. The substrate holding portion 2 holds the substrate 9 in a generally horizontal state by contacting the outer periphery of the lower surface 92 of the substrate 9 from below with the support pins 22, while maintaining a non-contact state at the center of the lower surface 92 of the substrate 9.

[0043] The gas supply section 23 includes a plurality of gas outlets 232 disposed on the base surface 210 of the base section 21. The plurality of gas outlets 232 are disposed downwards from the lower surface 92 of the substrate 9 at a position overlapping the substrate 9 when viewed from above. The plurality of gas outlets 232 are arranged circumferentially apart from each other on the same circumference centered on the central axis J1, located radially outwards from the central axis J1. The number of the plurality of gas outlets 232 is, for example, 150. The plurality of gas outlets 232 are circumferentially disposed below the outer periphery of the substrate 9, further radially inwards than the plurality of support pins 22.

[0044] Multiple gas outlets 232 are connected to a gas supply source (not shown) via gas flow paths 231 provided inside the base portion 21. Gas is discharged radially outward and upward (i.e., diagonally upward) from each gas outlet 232. The shape of the gas outlet 232, viewed along the gas discharge direction from the gas outlet 232, is, for example, approximately circular. The shape of the gas outlet 232 can also be varied. Furthermore, the arrangement or number of gas outlets 232 can also be varied.

[0045] The gas supply unit 23 also includes a central gas outlet 234 disposed at the center of the base surface 210. The central gas outlet 234 is, for example, a single outlet positioned above the lower surface 92 of the substrate 9, overlapping the central axis J1 when viewed from above. The central gas outlet 234 is connected to the gas supply source via a gas flow path 233 disposed inside the base unit 21. Gas is discharged from the central gas outlet 234 in a substantially vertically upward direction (i.e., along the central axis J1). The shape of the central gas outlet 234, viewed along the gas discharge direction from the central gas outlet 234, is, for example, substantially circular. The shape of the central gas outlet 234 can also be varied. Furthermore, the arrangement or number of central gas outlets 234 can also be varied.

[0046] In the gas supply section 23, gas is supplied from the central gas outlet 234 and multiple gas outlets 232 to the space (hereinafter also referred to as "lower space 90") between the lower surface 92 of the substrate 9 and the base surface 210 of the base section 21. The gas is, for example, an inert gas such as nitrogen or air. The gas is, for example, a high-pressure gas or a compressed gas. The gas supplied from the central gas outlet 234 and multiple gas outlets 232 flows radially outward in the lower space 90. As a result, an airflow from the radial center (hereinafter also simply referred to as "center") to the radial outward is formed in the lower space 90, and a pressure drop is generated in the lower space 90 due to the Bernoulli effect of the airflow. As a result, the substrate 9 is adsorbed onto the substrate holding section 2. In other words, the gas pressure in the lower space 90 is lower than the gas pressure above the substrate 9 (i.e., a negative pressure), and the substrate 9 is pressed against the multiple support pins 22 of the substrate holding section 2 by the pressure difference, thus fixing its position (i.e., holding).

[0047] With the substrate 9 held in the substrate holding portion 2, the base portion 21, the central gas outlet 234, and the multiple gas outlets 232 move downward from the substrate 9 and do not contact the substrate 9. In addition, when the substrate 9 is not adsorbed onto the substrate holding portion 2, the substrate 9 can easily move upward from the multiple support pins 22, and can also move approximately horizontally while in contact with the multiple support pins 22 (that is, slide laterally on the multiple support pins 22).

[0048] In the substrate holding section 2, multiple lifting pins and multiple centering pins (not shown) are provided on the base surface 210 of the base section 21. The lifting pins and centering pins are located radially outwards from the multiple support pins 22. The lifting pins facilitate the transfer of the substrate 9 between the substrate 9 and the multiple support pins 22 when the substrate processing apparatus 1 is moved in and out. The centering pins adjust the horizontal position of the substrate 9 by pressing the outer periphery of the substrate 9, which is placed on the multiple support pins 22 but not adsorbed, in a horizontal direction.

[0049] like Figure 2 As shown, the substrate rotation mechanism 33 is positioned below the substrate holding portion 2. The substrate rotation mechanism 33 rotates the substrate 9 together with the substrate holding portion 2 around a central axis J1. The substrate rotation mechanism 33 includes a shaft 331 and a motor 332. The shaft 331 is a generally cylindrical component centered on the central axis J1. The shaft 331 extends vertically and is connected to the center of the lower surface of the base portion 21 of the substrate holding portion 2. The motor 332 is an electric rotary motor that rotates the shaft 331. The shaft 331 rotates via the motor 332, causing the base portion 21 connected to the shaft 331 to rotate together. Alternatively, the substrate rotation mechanism 33 may also include a motor with other structures (e.g., a hollow motor).

[0050] The cup portion 4 has an annular cup 41 centered on the central axis J1. The cup 41 is arranged around the entire circumference of the substrate 9 and the substrate holding portion 2, covering the sides of the substrate 9 and the substrate holding portion 2. The cup 41 is a liquid receiving container for receiving liquids such as processing liquid that are scattered from the rotating substrate 9. The cup 41 remains stationary in the circumferential direction regardless of whether the substrate holding portion 2 is rotating or stationary. At the bottom of the cup 41, a drain port (not shown) is provided for discharging the processing liquid or the like received by the cup 41 to the outside of the chamber 11.

[0051] The cup 41 moves vertically via a lifting mechanism (not shown in the figure). This lifting mechanism may include, for example, an electric linear motor, a cylinder, a ball screw, or an electric rotary motor. The cup section 4 may also have multiple cups 41 stacked radially. When the cup section 4 has multiple cups 41, each cup 41 can move independently in the vertical direction. Depending on the type of processing liquid dispersing from the substrate 9, the multiple cups 41 can be switched for receiving the processing liquid.

[0052] The processing liquid supply unit 51 supplies processing liquid (e.g., cleaning liquid) to the upper surface 91 of the substrate 9. The processing liquid supply unit 51 includes an upper nozzle 511 for spraying the processing liquid onto the upper surface 91 of the substrate 9. The upper nozzle 511 is, for example, a two-fluid nozzle that mixes the processing liquid with gas and sprays the processing liquid onto the upper surface 91 of the substrate 9. In the processing liquid supply unit 51, the processing liquid is atomized by collision with the high-speed flow of gas and sprayed at high speed onto the upper surface 91 of the substrate 9 in a microparticle state. This physically cleans the upper surface 91 of the substrate 9, removing foreign matter adhering to it. The processing liquid is, for example, DIW or CO2 water. The gas is, for example, an inert gas such as nitrogen or air. The gas is, for example, a high-pressure gas or a compressed gas.

[0053] The processing unit moving mechanism 52 is a swinging mechanism that causes the upper nozzle 511 of the processing liquid supply unit 51 to swing approximately horizontally in the space above the substrate 9. The processing unit moving mechanism 52 includes an arm 521 and an arm rotating mechanism 522. The arm 521 is a rod-shaped member that extends approximately horizontally. The upper nozzle 511 is fixed at one end of the arm 521, and the other end is connected to the arm rotating mechanism 522, which is located radially outward of the cup portion 4. The arm rotating mechanism 522 causes the arm 521 to rotate approximately horizontally about a rotation axis that extends vertically.

[0054] The processing unit moving mechanism 52 reciprocates the upper nozzle 511, which sprays processing liquid onto the rotating substrate 9, between a first position facing vertically toward the center of the upper surface 91 of the substrate 9 and a second position further radially outward than the first position. The second position is preferably facing vertically toward the outer periphery of the upper surface 91 of the substrate 9. This allows the physical cleaning process to be performed on approximately the entire upper surface 91 of the substrate 9. When the cleaning process is complete, the processing unit moving mechanism 52 moves the upper nozzle 511 of the processing liquid supply unit 51 from the space above the substrate 9 to a retracted position further radially outward than the outer periphery of the substrate 9. The arm rotation mechanism 522 of the processing unit moving mechanism 52 may include, for example, an electric rotary motor. Other configurations are also possible for the processing unit moving mechanism 52.

[0055] like Figure 4 As illustrated, the base surface 210 of the base portion 21 extends approximately horizontally outward from the central axis J1, becoming an inclined surface extending upward from the radially outward below the outer periphery of the substrate 9. The base surface 210 faces downward further outward than the plurality of support pins 22, becoming a horizontal plane extending approximately horizontally outward from a position further outward than the outer periphery of the substrate 9 when viewed from above. The base surface 210 extends radially outward and downward from the radially outer end of said horizontal plane.

[0056] like Figure 3 and Figure 4 As shown, the base surface 210 includes a first surface 211, a second surface 212, a third surface 213, a fourth surface 214, and a fifth surface 215. The first surface 211, the second surface 212, the third surface 213, the fourth surface 214, and the fifth surface 215 are sequentially arranged radially outward from the central axis J1. The first surface 211 is a generally circular surface that extends approximately horizontally (that is, approximately perpendicular to the central axis J1) with the central axis J1 as its center. The first surface 211 faces the central portion of the substrate 9 in the vertical direction.

[0057] The second surface 212 is a generally annular surface extending radially outward from the generally circumferential outer periphery of the first surface 211, below the substrate 9. The outer periphery of the first surface 211 (i.e., the boundary between the first surface 211 and the second surface 212) overlaps with the substrate 9 when viewed from above. In the following description, "below the substrate 9" means overlapping with the substrate 9 when viewed from above, and located further down than the lower surface 92 of the substrate 9 in the vertical direction. The second surface 212 is an inclined surface that slopes upward as it extends radially outward from the outer periphery of the first surface 211. Figure 4 In the example shown, the second surface 212 is located lower than the lower surface 92 of the substrate 9 in the vertical direction. The longitudinal section of the second surface 212 is generally straight, and the angle of inclination (acute angle) of the second surface 212 relative to the horizontal direction is generally fixed. In other words, the second surface 212 is a flat inclined surface that faces upward from the outer periphery of the first surface 211 at a specific angle toward the radially outward. Alternatively, the second surface 212 may also be, for example, a curved surface that convexes radially inward and upward.

[0058] The plurality of support pins 22 are disposed on the second surface 212. The plurality of support pins 22 are located radially inward from the second surface 212, beyond the generally circumferential outer periphery of the second surface 212 (i.e., the upper edge of the second surface 212). Furthermore, the plurality of gas outlets 232 are disposed on the boundary between the second surface 212 and the first surface 211, or on the first surface 211 radially inward beyond the boundary.

[0059] The third surface 213 is a roughly annular surface that is lower than the lower surface 92 of the substrate 9 in the vertical direction and is continuous with the outer periphery of the second surface 212. Figure 4 In the example shown, the outer periphery of the second surface 212 (i.e., the boundary between the second surface 212 and the third surface 213) overlaps with the substrate 9 when viewed from above. In other words, the third surface 213 is continuous with the outer periphery of the second surface 212 below the substrate 9. The third surface 213 is an inclined surface that slopes downwards as it moves radially outwards from the outer periphery of the second surface 212. The third surface 213 is, for example, a curved surface that convexes upwards and outwards radially outwards. That is, the angle of inclination (acute angle) of the third surface 213 relative to the horizontal direction increases as it moves radially outwards. The third surface 213 is, for example, part of a generally annular outer surface centered on the central axis J1.

[0060] Alternatively, the third surface 213 can be a flat inclined surface with a substantially fixed inclination angle, or it can be a curved surface that bulges radially inward and downward. Furthermore, the third surface 213 can also be a surface that extends substantially vertically downward from the outer periphery of the second surface 212. In this case, the third surface 213 is a substantially cylindrical surface centered on the central axis J1.

[0061] The fourth face 214 is a roughly annular face that extends radially outward from the roughly circumferential lower edge of the third face 213. Figure 4 In the example shown, the fourth surface 214 extends approximately horizontally from the lower edge of the third surface 213. In other words, the fourth surface 214 is a horizontal plane that extends approximately perpendicular to the central axis J1 at approximately the same position in the vertical direction as the lower edge of the third surface 213. The lower edge of the third surface 213 (that is, the boundary between the third surface 213 and the fourth surface 214) is located radially outward than the outer periphery of the substrate 9. Therefore, the fourth surface 214 as a whole is located radially outward than the outer periphery of the substrate 9. Furthermore, if the third surface 213 is an inclined surface that extends radially outward and downward from the outer periphery of the second surface 212, the boundary between the third surface 213 and the fourth surface 214 is also the outer periphery of the third surface 213.

[0062] In the base surface 210, the fourth surface 214 may also be an inclined surface that slopes downwards from the lower edge of the third surface 213 toward the radially outward side. Furthermore, the boundary between the third surface 213 and the fourth surface 214 may be located at approximately the same radial position as the outer periphery of the substrate 9. In this case, the inner periphery of the fourth surface 214 overlaps with the outer periphery of the substrate 9 when viewed from above, and the portion of the fourth surface 214 other than its inner periphery is located radially outwards than the outer periphery of the substrate 9, and does not overlap with the substrate 9 when viewed from above. Alternatively, in the base surface 210, the boundary between the third surface 213 and the fourth surface 214 may be located radially inwards than the outer periphery of the substrate 9. In this case, the inner periphery of the fourth surface 214 overlaps with the outer periphery of the substrate 9 when viewed from above, and the portion of the fourth surface 214 other than its inner periphery is located radially outwards than the outer periphery of the substrate 9, and does not overlap with the substrate 9 when viewed from above.

[0063] The fifth surface 215 is a generally annular surface that extends radially outward from the generally circumferential outer periphery of the fourth surface 214. The outer periphery of the fourth surface 214 (that is, the boundary between the fourth surface 214 and the fifth surface 215) is located radially outward than the outer periphery of the substrate 9. The fifth surface 215 is an inclined surface that slopes downward as it moves radially outward from the outer periphery of the fourth surface 214. Figure 4 In the example shown, the longitudinal section of the fifth surface 215 is approximately straight, and the angle of inclination (acute angle) of the fifth surface 215 relative to the horizontal direction is approximately fixed. Alternatively, the fifth surface 215 may also be a curved surface that convexes radially outward and upward.

[0064] Figure 5 This is a magnified view of the area near the outer periphery of the base portion 21. Because... Figure 5 This is a longitudinal sectional view of the base portion 21 at the location where the support pin 22 is not configured, so Figure 5 In the diagram, the support pin 22 is depicted with a dashed line. In the substrate processing apparatus 1, as described above, gas is supplied from the central gas outlet 234 (reference 234). Figure 4The gas delivered from the gas outlets 232 and the gas outlets 232 form an airflow in the lower space 90 from the radial center to the radially outward. Furthermore, through the Bernoulli effect of the airflow, a pressure drop is generated in the lower space 90, which adsorbs the substrate 9 onto the substrate holding part 2. Figure 5 In the diagram, the airflow is schematically represented by an arrow marked with symbol 93. In the substrate processing apparatus 1, the substrate 9 is transported by the substrate rotation mechanism 33 (see reference 33). Figure 2 The substrate 9 rotates, thereby increasing the speed of the airflow 93 through centrifugal force. In other words, with the substrate 9 rotating, the flow rate of the gas in the lower space 90 towards the radially outward direction increases. In this embodiment, the rotational speed of the substrate 9 is, for example, 200 rpm to 1500 rpm. The flow rate of the gas supplied to the lower space 90 from the central gas outlet 234 and the multiple gas outlets 232 is, for example, 270 L / min to 300 L / min.

[0065] Furthermore, in the substrate processing apparatus 1, the gas on the upper surface 91 of the substrate 9 moves radially outward due to the centrifugal force of the rotating substrate 9. As a result, an airflow from the radial center toward the radial outward is formed on the upper surface 91 of the substrate 9. Figure 5 In the diagram, the airflow is schematically represented by an arrow marked 94. The airflow 94, flowing radially outward along the upper surface 91 of the substrate 9, flows radially outward and downward along the base surface 210, further radially outward than the outer periphery of the substrate 9, due to the Coanda effect generated between the airflow and the base surface 210. Consequently, a downward force acts on the portion near the outer periphery of the substrate 9, pressing the outer periphery of the substrate 9 against the multiple support pins 22. As a result, the stability of the substrate holding portion 2 in holding the substrate 9 is improved. In other words, in the substrate processing apparatus 1, the substrate 9 is firmly held by the substrate holding portion 2 through the Bernoulli effect of the airflow 93 and the Coanda effect of the airflow 94.

[0066] In the substrate processing apparatus 1, the processing liquid supplied to the upper surface 91 of the substrate 9, as described above, moves radially outward due to the centrifugal force of the rotating substrate 9, and is dispersed radially outward from the outer periphery of the substrate 9. The negative pressure of the Bernoulli effect exerts a force on the processing liquid near the outer periphery of the substrate 9, causing it to circulate back towards the lower surface 92 of the substrate 9. On the other hand, the airflow 94 flowing from the outer periphery of the substrate 9 along the base surface 210, utilizing the Coanda effect, also exerts a force on the processing liquid near the outer periphery of the substrate 9, causing it to circulate radially outward and downward from the outer periphery of the substrate 9. This prevents the processing liquid on the upper surface 91 of the substrate 9 from circulating back and adhering to the lower surface 92 of the substrate 9.

[0067] In the substrate holding section 2, as described above, the second surface 212 of the base section 21 is provided as an inclined surface that faces upward toward the radially outward side below the outer periphery of the substrate 91. As a result, the vertical height (hereinafter also simply referred to as "height") of the lower space 90 gradually decreases below the outer periphery of the substrate 9, increasing the velocity of the airflow 93. Consequently, the Bernoulli effect of the substrate 9's adsorption force (that is, the force that presses the substrate 9 against the multiple support pins 22 through the Bernoulli effect) can be increased. Furthermore, since the vertical distance between the first surface 211 and the lower surface 92 of the substrate 9 can be relatively large, the pressure from the central gas outlet 234 (see reference 234) can be suppressed. Figure 4 The gas delivered from multiple gas outlets 232 pushes the substrate 9 upwards.

[0068] In the substrate holding section 2, by providing a third surface 213 extending downward from the outer periphery of the second surface 212, the force pressing the substrate 9 against the multiple support pins 22 can be increased through the Coanda effect. As a result, the stability of holding the substrate 9 can be improved. Furthermore, since the processing liquid on the upper surface 91 of the substrate 9 can be guided downward from the outer periphery by the airflow 94 utilizing the Coanda effect, the processing liquid can be prevented from flowing back to the lower surface 92 (that is, from the outer periphery of the substrate 9 to the radially inward side).

[0069] In the substrate holding section 2, by providing a fourth surface 214 extending radially outward from the outer periphery of the third surface 213, the airflow 94 from the outer periphery of the substrate 9 towards the lower side is guided radially outward through the Coanda effect. This further suppresses the processing liquid on the upper surface 91 of the substrate 9 from swirling back and adhering to the lower surface 92 of the substrate 9. Furthermore, the fourth surface 214 does not extend upward beyond the lower edge of the third surface 213, thereby appropriately forming an airflow 94 from the outer periphery of the substrate 9 towards the radially outward and downward side. This further improves the stability of substrate 9 holding. Additionally, from the viewpoint of improving the stability of substrate 9 holding, it is preferable not to provide an upwardly protruding annular structure on the fourth surface 214.

[0070] In the substrate holding section 2, by further providing a fifth surface 215 that moves radially outward and downward from the outer periphery of the fourth surface 214, the airflow 93 moving radially outward is guided obliquely downward along the fourth surface 214. This suppresses turbulence caused by the collision (i.e., merging) of the airflow 93 with the airflow 94 moving radially outward and downward from the outer periphery of the substrate 9. As a result, the Coanda effect allows for appropriate downward pressing of the outer periphery of the substrate 9, further improving the stability of the substrate 9's holding.

[0071] like Figure 6As shown, in the substrate holding portion 2, when the radial distance between the boundary of the second surface 212 and the third surface 213 located below the substrate 9 (that is, the inner periphery of the third surface 213) and the outer periphery of the substrate 9 is set to L1, the distance L1 is preferably 0.5 mm or more and 2.0 mm or less. With the distance L1 being 0.5 mm or more, the airflow 93 passing radially outward from the boundary of the second surface 212 and the third surface 213 (see reference) can be suppressed. Figure 5 The airflow 94 (referring to the airflow 93) moves radially outward and upward from the outer periphery of the substrate 9. This suppresses the airflow 93 and the Coanda effect. Figure 5 The particles collide near the outer periphery of substrate 9, generating turbulence. As a result, the Coanda effect can appropriately press the outer periphery of substrate 9 downwards, further improving the stability of substrate 9. On the other hand, by setting the distance L1 to less than 2.0 mm, the adsorption force of the Coanda effect can be appropriately applied near the outer periphery of substrate 9. As a result, the stability of substrate 9 can be further improved.

[0072] In the substrate holding section 2, the vertical distance L2 between the boundary of the second surface 212 and the third surface 213 and the lower surface 92 of the substrate 9 is preferably 0.6 mm or more and 1.0 mm or less. With a distance L2 of 0.6 mm or more, excessive velocity of the airflow 93 passing radially outward from the boundary of the second surface 212 and the third surface 213 can be suppressed. This prevents the airflow 93 from colliding with the Coanda effect airflow 94 near the outer periphery of the substrate 9, thus preventing turbulence. As a result, the Coanda effect can appropriately press the outer periphery of the substrate 9 downward, further improving the stability of the substrate 9. On the other hand, with a distance L2 of 1.0 mm or less, the velocity of the airflow 93 below the outer periphery of the substrate 9 can be suppressed, preventing the Bernoulli effect from having an excessively weak adsorption force on the substrate 9. Furthermore, the negative pressure of the Bernoulli effect near the outer periphery of the substrate 9 can be appropriately suppressed, preventing the processing liquid from flowing back to the lower surface 92 of the substrate 9 due to the Bernoulli effect. As a result, the adhesion of the processing liquid to the lower surface 92 of the substrate 9 can be further suppressed.

[0073] In the substrate holding portion 2, the tilt angle θ of the second surface 212 is preferably 15° or less. This suppresses excessive pressure rise in the space 90 below the plurality of support pins 22. Consequently, it prevents the Bernoulli effect from hindering the adsorption of the substrate 9 due to excessive pressure rise, further improving the stability of the substrate 9's holding. Furthermore, if the second surface 212 is a curved surface convex radially inward and upward, the tilt angle θ is the angle (acute angle) formed by an imaginary straight line connecting the inner and outer peripheries of the second surface 212 and a straight line extending horizontally on the longitudinal section of the substrate holding portion 2 passing through the central axis J1. While the lower limit of the tilt angle θ of the second surface 212 is not particularly limited, in practice, the tilt angle θ is 10° or more.

[0074] In the substrate holding portion 2, the radial length L3 of the second surface 212 (that is, the shortest radial distance between the inner and outer peripheries of the second surface 212) is preferably 10 mm or more. This prevents the tilt angle θ of the second surface 212 from becoming too large, and increases the velocity of the airflow 93 below the outer periphery of the substrate 9. As a result, the Bernoulli effect's adsorption force on the substrate 9 can be appropriately increased, further improving the stability of the substrate 9's holding. While the upper limit of the radial length L3 of the second surface 212 is not specifically limited, in practice, the length L3 is 20 mm or less.

[0075] In the substrate holding section 2, the vertical distance L4 between the first surface 211 and the lower surface 92 of the substrate 9 is preferably 0.6 mm or more and 1.5 mm or less. By having a distance L4 of 0.6 mm or more, the flow from the central gas outlet 234 (reference) can be suppressed. Figure 4 The gas delivered from multiple gas outlets 232 pushes the substrate 9 upwards. Furthermore, by maintaining a distance of less than 1.5 mm from L4, the velocity reduction of the airflow 93 below the substrate 9 can be suppressed, thus preventing the Bernoulli effect from causing excessively weak adsorption force on the substrate 9. As a result, the stability of the substrate 9's retention can be further improved.

[0076] In the substrate holding portion 2, the vertical height L5 of the third surface 213 (that is, the vertical distance between the upper and lower edges of the third surface 213) is preferably 1 mm or more. This strengthens the Coanda effect and further improves the stability of the substrate 9. Although the upper limit of the height L5 of the third surface 213 is not particularly limited, in practice, the height L5 is 10 mm or less.

[0077] As described above, the substrate processing apparatus 1 for processing substrate 9 includes a substrate holding section 2, a substrate rotation mechanism 33, and a processing liquid supply section 51. The substrate holding section 2 holds the substrate 9 in a horizontal position. The substrate rotation mechanism 33 rotates the substrate holding section 2 about a central axis J1 in the vertical direction. The processing liquid supply section 51 supplies processing liquid to the upper surface 91 of the substrate 9. The substrate holding section 2 includes a base section 21, multiple support pins 22, and a gas supply section 23. The base section 21 faces the lower surface 92 of the substrate 9. The base section 21 has a base surface 210 extending radially outward from the outer periphery of the substrate 9. The multiple support pins 22 are arranged circumferentially on the base surface 210. The multiple support pins 22 protrude upward from the base surface 210 and contact the outer periphery of the lower surface 92 of the substrate 9. The gas supply section 23 delivers gas between the lower surface 92 of the substrate 9 and the base surface 210 of the base section 21, forming an airflow 93 toward the radially outward direction. Through the Bernoulli effect, a pressure drop is generated in the space between the substrate 9 and the base section 21 (that is, the lower space 90).

[0078] The base surface 210 includes a first surface 211, a second surface 212, a third surface 213, and a fourth surface 214. The first surface 211 is a horizontal, circular surface facing the center of the substrate 9 in the vertical direction. The second surface 212 is an annular surface extending radially outward from the outer periphery of the first surface 211 below the substrate 9. The second surface 212 faces upward as it moves radially outward. The plurality of support pins 22 are disposed on the second surface 212. The third surface 213 is an annular surface continuous with the outer periphery of the second surface 212 below the lower surface 92 of the substrate 9. The third surface 213 extends vertically downward from the outer periphery of the second surface 212. Alternatively, the third surface 213 faces downward as it moves radially outward from the outer periphery of the second surface 212. The fourth surface 214 is an annular surface continuous with the lower edge of the third surface 213. The fourth surface 214 extends radially outward beyond the outer periphery of the substrate 9. The gas supply section 23 has a circumferential gas outlet 232 disposed on the boundary between the first surface 211 and the second surface 212 or on the first surface 211, which supplies gas radially outward.

[0079] In the substrate processing apparatus 1, as described above, the airflow 94, through the Bernoulli effect and the Coanda effect of the airflow 93, can suppress the adhesion of the processing liquid to the lower surface 92 of the substrate 9 and improve the stability of the substrate 9.

[0080] In the substrate processing apparatus 1, the fourth surface 214 preferably extends to the same position as the lower edge of the third surface 213 in the vertical direction, or faces downwards as it moves radially outwards from the lower edge of the third surface 213. Thus, as described above, the airflow 94 moving downwards from the outer periphery of the substrate 9 is appropriately guided radially outwards via the Coanda effect. As a result, the adhesion of the processing liquid to the lower surface 92 of the substrate 9 can be further suppressed, and the stability of the substrate 9 can be further improved.

[0081] In the substrate processing apparatus 1, the base surface 210 preferably also has an annular fifth surface 215 that extends radially outward from the outer periphery of the fourth surface 214 and downwards. As described above, this enhances the Coanda effect and further improves the stability of the substrate 9.

[0082] As described above, the third surface 213 is preferably a curved surface that bulges radially outward and upward from the outer periphery of the second surface 212 towards the lower surface. This strengthens the Coanda effect and further improves the stability of the substrate 9.

[0083] Figures 7A to 7C This is a diagram of gas flow obtained through CFD (Computational Fluid Dynamics) simulation when the shape of the third face 213 is changed. Figures 7A to 7CThe figure shows the gas flow near the outer periphery of substrate 9. The CFD simulation, performed using Ansys Fluent (manufactured by Ansys Corporation), sets the rotational speed of substrate 9 to 1500 rpm, and the gas flows from gas supply section 23 (reference). Figure 4 The gas supply to the lower space 90 is set at a rate of 300 L / min. Additionally, Figures 7A to 7C In this case, the shape of the second face 212 is slightly different from that in the example described, but the tendency of the CFD simulation results is not significantly different.

[0084] Figure 7A In the middle, the third surface 213 is a curved surface that extends radially outward and downward from the outer periphery of the second surface 212, and simultaneously protrudes radially outward and upward. The tilt angle of the third surface 213 relative to the horizontal direction (that is, the angle (acute angle) formed by the imaginary straight line connecting the inner and outer peripheries of the third surface 213 and the straight line extending in the horizontal direction in the longitudinal section of the substrate holding part 2 through the central axis J1) is approximately 50°. Figure 7B In this context, the third surface 213 is a flat, sloping surface that extends radially outward and downward from the outer periphery of the second surface 212. The sloping angle of the third surface 213 relative to the horizontal direction is approximately 45°. From the viewpoint of properly generating the Coanda effect, Figure 7A and Figure 7B The tilt angle of the third surface 213 shown is preferably 30° or more. Figure 7C In the middle, the third surface 213 is a cylindrical surface that extends vertically downward from the outer periphery of the second surface 212.

[0085] like Figures 7A to 7C As shown, it can be seen that when the third surface 213 is the curved surface (and... Figure 7A Correspondingly, near the outer periphery of substrate 9 (i.e., radially outward from the outer periphery of substrate 9), the gas flow from above substrate 9 toward the radially outward is most concave downward, and the Coanda effect is maximized. When the third surface 213 is the curved surface, the holding force (i.e., the adsorption force) acting on substrate 9 is greater than when the third surface 213 is the inclined surface or the cylindrical surface (compared to...). Figure 7B or Figure 7C The corresponding holding force is about 1% to 2% greater.

[0086] In the substrate processing apparatus 1, it is preferable that the third surface 213 is continuous with the outer periphery of the second surface 212 below the substrate 9. This suppresses the airflow 93 (see reference) from the boundary between the second surface 212 and the third surface 213 toward the radially outward direction. Figure 5 ), and the gas flow 94 (reference) from the outer periphery of substrate 9 toward the radially outward and downward direction via the Coanda effect. Figure 5Collisions near the outer periphery of substrate 9 generate turbulence. Therefore, the Coanda effect can appropriately press the outer periphery of substrate 9 downwards, further improving the stability of substrate 9.

[0087] Figures 8A to 8C This is a diagram obtained through CFD simulation of the gas flow when the boundary between the second surface 212 and the third surface 213 is changed, and the positional relationship with the outer periphery of the substrate 9 is altered. Figures 8A to 8C In the CFD simulation representing the gas flow near the outer periphery of substrate 9, the rotational speed of substrate 9 was set to 1000 rpm and the gas supply rate from gas supply section 23 to the lower space 90 was set to 300 L / min using Ansys Fluent (manufactured by Ansys Corporation). Furthermore, Figures 8A to 8C In this example, the shapes of the second surface 212 and the third surface 213 are slightly different from those of the example described above, but the tendencies of the CFD simulation results are not significantly different.

[0088] Figure 8A In the middle, the boundary between the second surface 212 and the third surface 213 is located below the substrate 9, and the distance L1 (that is, the radial distance between the boundary between the second surface 212 and the third surface 213 and the outer periphery of the substrate 9) is 0.5 mm. Figure 8B In the middle, the boundary between the second surface 212 and the third surface 213 is located below the substrate 9, at a distance of 3.5 mm from L1. Figure 8C In this configuration, the boundary between the second surface 212 and the third surface 213 is not located below the substrate 9, but rather radially outward from the outer periphery of the substrate 9. Figure 8A The position shown is 3.0 mm further outward radially.

[0089] like Figure 8C As shown, when the boundary between the second surface 212 and the third surface 213 is not located below the substrate 9, near the outer periphery of the substrate 9 (i.e., radially outward from the outer periphery of the substrate 9), the gas flow from above the substrate 9 towards the radially outward collides with the gas flow from below the substrate 9 towards the radially outward , generating turbulence. On the other hand, as... Figure 8A and Figure 8B As shown, when the boundary between the second surface 212 and the third surface 213 is located below the substrate 9, the flow of gas from above the substrate 9 toward the radially outward side and its collision with the flow of gas from below the substrate 9 toward the radially outward side are suppressed near the outer periphery of the substrate 9. As a result, the outer periphery of the substrate 9 is appropriately pressed downward through the Coanda effect, improving the stability of the substrate 9. The holding force (i.e., the adsorption force) acting on the substrate 9 when the boundary between the second surface 212 and the third surface 213 is located below the substrate 9 is about 7% to 8% greater than the holding force when the boundary is not located below the substrate 9.

[0090] In addition, such as Figure 8A and Figure 8B As shown, the case where the distance L1 is 0.5mm or more and 2.0mm or less (compared to...) Figure 8A (corresponding to) and the case where the distance L1 is greater than 2.0 mm (and) Figure 8B In contrast, the gas flow from above the substrate 9 toward the radially outward direction causes a significant downward indentation near the outer periphery of the substrate 9. Therefore, it can be seen that when the distance L1 is 0.5 mm or more and 2.0 mm or less, the Coanda effect becomes larger, and the stability of the substrate 9 is improved.

[0091] Various modifications can be made to the substrate processing apparatus 1.

[0092] For example, the number and shape of the support pins 22 are not limited to the example described, and various modifications can be made. Furthermore, the number, shape, and arrangement of the gas outlets 232 are not limited to the example described, and various modifications can be made. For example, a single gas outlet in a generally annular shape centered on the central axis J1 may be provided on the base surface 210 instead of multiple gas outlets 232.

[0093] In the substrate holding portion 2, the shape or size of the base surface 210 is not limited to the example described above and can be modified in various ways. For example, the vertical distance L4 between the first surface 211 and the lower surface 92 of the substrate 9 may be less than 0.6 mm or greater than 1.5 mm. Furthermore, the vertical distance L2 between the boundaries of the second surface 212 and the third surface 213 and the lower surface 92 of the substrate 9 may be less than 0.6 mm or greater than 1.0 mm. The radial distance L1 between the boundaries of the second surface 212 and the third surface 213 and the outer periphery of the substrate 9 may be less than 0.5 mm or greater than 2.0 mm.

[0094] In the substrate holding portion 2, the radial length L3 of the second surface 212 may be less than 10 mm. Furthermore, the tilt angle θ of the second surface 212 may be greater than 15°. The second surface 212 does not need to be tilted across its entire periphery from the inner edge to the outer edge; for example, the portion near the outer periphery of the second surface 212 may be a horizontal plane approximately perpendicular to the central axis J1. In this case, multiple support pins 22 may be arranged on the horizontal plane.

[0095] In the substrate holding portion 2, the third surface 213 may also be continuous with the outer periphery of the second surface 212 further radially outward than the outer periphery of the substrate 9.

[0096] In the substrate holding portion 2, the fourth surface 214 may also extend upward from the lower edge of the third surface 213 toward the radially outward side. Furthermore, the base surface 210 may not include the fifth surface 215.

[0097] In the example described, the thickness of the substrate 9 processed by the substrate processing apparatus 1 is generally uniform across the entire surface in the vertical direction, but this is not a limitation. For example, the substrate 9 may also be a substrate with a thickness at the outer periphery that is thicker than the region further inward than the outer periphery (hereinafter also referred to as the "main portion"). The upper surface 91 of the substrate 9 is recessed, for example, in the main portion downwards than in the outer periphery. The substrate 9 is formed, for example, by grinding (i.e., pulverizing) the portion corresponding to the main portion of a substrate having a generally uniform thickness.

[0098] In addition to semiconductor substrates, the substrate processing apparatus 1 can also be used for processing glass substrates for flat panel displays such as liquid crystal displays or organic EL (electroluminescence) display devices, or for processing glass substrates for other display devices. Furthermore, the substrate processing apparatus 1 can also be used for processing substrates for optical discs, magnetic disks, magneto-optical discs, photomasks, ceramic substrates, and solar cells.

[0099] The components of the described implementation methods and variations can be appropriately combined as long as they do not contradict each other.

[0100] Although the invention has been described in detail, the description is illustrative and not limiting. Therefore, it can be said that various variations or forms can be achieved without departing from the scope of the invention.

[0101] [Symbol Explanation]

[0102] 1 Substrate processing apparatus

[0103] 2 Substrate holding section

[0104] 5. Processing fluid supply unit

[0105] 9 Substrates

[0106] 21. Base section

[0107] 22 Support pins

[0108] 23 Gas Supply Department

[0109] 33 Substrate Rotation Mechanism

[0110] 51 Processing Fluid Supply Department

[0111] 90% space below

[0112] 91 (substrate) upper surface

[0113] 92 (substrate) lower surface

[0114] 210 Base surface

[0115] 211 Page 1

[0116] 212 Page 2

[0117] 213 Page 3

[0118] 214 Page 4

[0119] 215 Page 5

[0120] 232 Gas outlet

[0121] J1 central axis.

Claims

1. A substrate processing apparatus for processing a substrate, comprising: The substrate holding section holds the substrate in a horizontal position; A substrate rotation mechanism is used to rotate the substrate holding portion about a central axis pointing vertically; and The processing liquid supply unit supplies processing liquid to the upper surface of the substrate; The substrate holding portion includes: The base portion has a base surface facing the lower surface of the substrate and extending radially outward from the outer periphery of the substrate; Multiple support pins are arranged circumferentially on the base surface and project upwards from the base surface, contacting the outer periphery of the lower surface of the substrate; and The gas supply section delivers gas between the lower surface of the substrate and the base surface of the base portion, forming an airflow toward the radially outward direction, and generates a pressure drop in the space between the substrate and the base portion through the Bernoulli effect; The base surface has: The first surface is a horizontal circular surface that faces the center of the substrate in the vertical direction; The second surface is an annular surface that extends radially outward from the outer periphery of the first surface below the substrate, facing upward as it moves radially outward, and is used for the arrangement of the plurality of support pins; The third surface is an annular surface that is continuous with the outer periphery of the second surface below the lower surface of the substrate, extending vertically downward from the outer periphery of the second surface, or downward as it moves radially outward; and The fourth surface is an annular surface that is continuous with the lower edge of the third surface, extending radially outward beyond the outer periphery of the substrate. The gas supply unit has a circumferential gas outlet disposed on the boundary between the first surface and the second surface or on the first surface, which supplies gas radially outward.

2. The substrate processing apparatus according to claim 1, wherein The fourth surface extends in the vertical direction to the same position as the lower edge of the third surface, or downwards as it moves radially outwards from the lower edge of the third surface.

3. The substrate processing apparatus according to claim 1 or 2, wherein The base surface also has a fifth annular surface that faces downwards from the outer periphery of the fourth surface toward the radially outward side.

4. The substrate processing apparatus according to claim 1 or 2, wherein The third surface is a curved surface that convexes downwards and outwards radially outwards from the outer periphery of the second surface.

5. The substrate processing apparatus according to claim 1 or 2, wherein The third surface is continuous with the outer periphery of the second surface below the substrate.

6. The substrate processing apparatus according to claim 5, wherein The radial distance between the boundary between the second surface and the third surface and the outer periphery of the substrate is more than 0.5 mm and less than 2.0 mm.

7. The substrate processing apparatus according to claim 1 or 2, wherein The vertical distance between the boundary between the second and third surfaces and the lower surface of the substrate is greater than 0.6 mm and less than 1.0 mm.

8. The substrate processing apparatus according to claim 1 or 2, wherein The second surface is an inclined surface that extends radially outward and upward from the outer periphery of the first surface at a specific angle. The tilt angle of the second surface is less than 15°.

9. The substrate processing apparatus according to claim 1 or 2, wherein The radial length of the second surface is 10 mm or more.

10. The substrate processing apparatus according to claim 1 or 2, wherein The vertical distance between the first surface and the lower surface of the substrate is more than 0.6 mm and less than 1.5 mm.

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