Substrate processing apparatus

Abstract

The invention provides a substrate processing apparatus, which can remove organic matters in gaps between fine structures formed on the surface of a substrate. The substrate processing method of the substrate processing apparatus includes a substrate holding step and an ultraviolet irradiation step. In the substrate holding step, the substrate having the microstructure formed on the surface thereof is held. In the ultraviolet irradiation step, the surface of the substrate is irradiated with ultraviolet light by an ultraviolet irradiator which faces the surface of the substrate across the processing space. In at least a part of the period of the ultraviolet irradiation step, a gas is supplied to the processing space and the oxygen concentration in the processing space is adjusted to a concentration range of 0.3 vol% or more and 8.0 vol% or less.

Description

[0001] The international application date of this invention is January 22, 2020, the international application number is PCT / JP2020 / 002026, the application number entering the Chinese national phase is 202080019298.4, and the invention name is a divisional application for a substrate processing method and a substrate processing device. Technical Field

[0002] The invention relates to a substrate processing method and a substrate processing device. Background Art

[0003] Conventionally, in the manufacturing process of semiconductor substrates (hereinafter referred to as "substrates"), various processes are performed on the substrates using substrate processing equipment. For example, a chemical solution is supplied to a substrate having a resist pattern formed on the surface, thereby performing an etching process (so-called wet etching) on ​​the surface of the substrate. After the etching process, a rinsing process is performed in which the chemical solution is supplied to the substrate to rinse the surface, and a drying process is performed in which the pure water on the surface is removed.

[0004] When a plurality of fine patterns (hereinafter also referred to as fine structures) are formed on the surface of a substrate, when a cleaning process and a drying process are performed in sequence, the surface tension of pure water may act on the fine structures during the drying process, causing the fine structures to collapse. The narrower the width of the fine structures and the higher the aspect ratio, the more likely such collapse will occur.

[0005] In order to suppress such collapse, a waterproofing treatment is proposed to waterproof (hydrophobize) the surface of the microstructure to form a waterproof film (organic film). In this waterproofing treatment, a silylating agent is often used as a waterproofing agent, and in order to enhance the waterproofing effect of the silylating agent, an activator is also mixed into the silylating agent.

[0006] On the other hand, after the drying process, a waterproof film is no longer required. Therefore, a method for removing organic matter has been proposed in the past (for example, Patent Documents 1 and 2). In Patent Documents 1 and 2, an ultraviolet irradiation device for irradiating ultraviolet rays is used as an organic matter removal device. Ultraviolet rays are irradiated to the main surface of the substrate on which the organic matter is formed, so that the ultraviolet rays act on the organic matter, decompose the organic matter, and remove it.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Publication No. 2011-204944.

[0010] Patent document 2: Japanese Patent Application Publication No. 2018-166183. Summary of the invention

[0011] Problems to be solved by the invention

[0012] From the perspective of decomposing organic matter, it is preferable to use ultraviolet light with high photon energy, that is, ultraviolet light with short wavelength. The reason is that the higher the photon energy, the more types of molecular bonds can be cut, thereby rapidly decomposing organic matter.

[0013] On the other hand, the pattern on the substrate is miniaturized. That is, as the width of the microstructure becomes narrower, the gap between the microstructures also becomes narrower. Thus, when the gap between the microstructures becomes narrower, it is more difficult for ultraviolet rays with shorter wavelengths to enter the gap. The reason is that ultraviolet rays with short wavelengths are difficult to diffract. Thus, when it is difficult for ultraviolet rays to enter the gap, it is difficult for ultraviolet rays to act on organic matter present in the gap. Therefore, the removal of organic matter is insufficient.

[0014] Therefore, an object of the present invention is to provide a substrate processing method and a substrate processing apparatus capable of removing organic matter even in gaps between microstructures formed on the surface of a substrate.

[0015] Means for solving problems

[0016] The first type of substrate processing method comprises: a substrate holding step for holding a substrate having a microstructure formed on its surface; and an ultraviolet irradiation step for irradiating the surface of the substrate with ultraviolet rays by an ultraviolet irradiator disposed opposite to the surface of the substrate across a processing space, and during at least a portion of the ultraviolet irradiation step, gas is supplied to the processing space to adjust the oxygen concentration in the processing space to a concentration range of greater than 0.3 vol% and less than 8.0 vol%.

[0017] A second aspect of the substrate processing method is the substrate processing method according to the first aspect, wherein during at least a portion of the ultraviolet irradiation step, the oxygen concentration in the processing space is adjusted to a concentration range of 0.6 vol% to 7.0 vol%.

[0018] A substrate processing method according to a third aspect is the substrate processing method according to the first aspect or the second aspect, wherein an inert gas and oxygen are supplied to the processing space as the gas.

[0019] The fourth mode of the substrate processing method is a substrate processing method described in any one of the first to third modes, wherein the flow rate of the gas is controlled so that the concentration value detected by the oxygen concentration sensor located downstream of the flow of the gas relative to the processing space is within the concentration range.

[0020] A fifth aspect of the substrate processing method is the substrate processing method according to any one of the first to fourth aspects, wherein in the ultraviolet irradiation step, ultraviolet rays having different peak wavelengths are irradiated onto the surface of the substrate from a plurality of ultraviolet irradiators.

[0021] A sixth aspect of the substrate processing method is the substrate processing method according to any one of the first to fifth aspects, wherein the microstructure includes a pattern having a pattern width of 50 nm or less and an aspect ratio of 3.5 or more.

[0022] A substrate processing device of the first type comprises: a substrate holding portion that holds a substrate; an ultraviolet irradiator that is opposite to the surface of the substrate across a processing space; a gas supply portion that supplies gas to the processing space; and a control portion that controls so that the gas supply portion supplies the gas so that the oxygen concentration in the processing space becomes within a concentration range of greater than 0.3 vol% and less than 8.0 vol%, and ultraviolet rays are irradiated from the ultraviolet irradiator to the surface of the substrate.

[0023] A substrate processing apparatus according to a second aspect is the substrate processing apparatus according to the first aspect, wherein the gas supply unit supplies an inert gas and oxygen as the gas to the processing space.

[0024] The substrate processing device of the third embodiment is the substrate processing device described in the first embodiment or the second embodiment, wherein the device further comprises: an oxygen concentration sensor, which is arranged on the downstream side of the flow of the gas relative to the processing space, and the control unit controls the flow rate of the gas according to the concentration value detected by the oxygen concentration sensor so that the oxygen concentration in the processing space becomes within the concentration range of greater than 0.3 vol% and less than 8.0 vol%.

[0025] Effects of the Invention

[0026] According to the substrate processing method of the first and sixth aspects and the substrate processing apparatus of the first aspect, the amount of ozone generated near the surface of the substrate can be increased. Since the ozone generated near the surface of the substrate easily enters the gaps between the microstructures, organic matter existing in the gaps can be removed.

[0027] According to the second embodiment of the substrate processing method, organic matter in the gaps of the microstructure can be removed more appropriately. According to the second embodiment of the substrate processing method and the second embodiment of the substrate processing device, the oxygen concentration in the processing space can be changed rapidly. In particular, the oxygen concentration in the processing space can be increased rapidly by supplying oxygen.

[0028] According to the substrate processing method of the fourth aspect and the substrate processing apparatus of the third aspect, the oxygen concentration sensor does not hinder the ultraviolet irradiation of the ultraviolet irradiator, and the oxygen concentration in the processing space can be more reliably adjusted to within the concentration range.

[0029] According to the substrate processing method of the fifth aspect, the intensity of ultraviolet rays can be increased in a wider area in the gap of the microstructure, thereby increasing the amount of ozone generated in the gap, thereby more appropriately removing organic matter in the gap. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a diagram schematically showing an example of the structure of a substrate processing apparatus.

[0031] Figure 2 It is a diagram schematically showing an example of the structure of a substrate processing apparatus.

[0032] Figure 3 This is a diagram schematically showing an example of ultraviolet intensity distribution.

[0033] Figure 4 It is a graph showing the relationship between the contact angle and the oxygen concentration.

[0034] Figure 5 This is a flowchart showing an example of the operation of the substrate processing apparatus.

[0035] Figure 6 It is a diagram schematically showing another example of the structure of the substrate processing apparatus.

[0036] Figure 7 This is a diagram schematically showing an example of the electrical configuration of a substrate processing apparatus.

[0037] Figure 8 It is a diagram schematically showing another example of the structure of the substrate processing apparatus.

[0038] Fig. 9 It is a diagram schematically showing another example of the structure of the substrate processing apparatus.

[0039] Fig.10 This is a diagram schematically showing an example of ultraviolet intensity distribution.

[0040] Fig.11 This is a graph schematically showing an example of the intensity of ultraviolet rays. DETAILED DESCRIPTION

[0041] Hereinafter, the implementation mode will be described in detail with reference to the accompanying drawings. In order to illustrate the positional relationship of each structure, the accompanying drawings are appropriately marked with an XYZ orthogonal coordinate system with the Z direction as the vertical direction and the XY plane as the horizontal plane. In addition, for the purpose of easy understanding, the size and quantity of each part are exaggerated or simplified as needed. In addition, the expressions "+Z axis side" and "-Z axis side" are appropriately introduced below. "+Z axis side" means the upper side in the Z direction, and "-Z axis side" means the lower side in the Z direction.

[0042] First embodiment

[0043] <Substrate processing apparatus>

[0044] Figure 1 and Figure 2 1 is a diagram schematically showing an example of the structure of the substrate processing device 10. The substrate W1 is carried into the substrate processing device 10. The substrate W1 is a semiconductor substrate, and a plurality of fine structures (not shown) are formed on the surface (main surface) of the substrate W1. The so-called fine structures refer to patterns such as metal patterns, semiconductor patterns, and resistor patterns. Therefore, the main surface of the substrate W1 presents a concave-convex shape caused by the fine structures.

[0045] The microstructure is formed in a process before the substrate W1 is moved into the substrate processing device 10. For example, a chemical solution is supplied to the substrate W1 on which a resistance pattern is formed to perform an etching process, thereby forming a metal or other pattern on the main surface of the substrate W1. After the etching process, a cleaning process, a waterproofing process and a drying process are performed. The cleaning process is a process in which pure water is supplied to the substrate W1 to rinse the chemical solution. The drying process is, for example, a process in which the substrate W1 is dried by rotating the substrate W1 in a horizontal plane. During the drying process, the microstructure may collapse due to the surface tension of the pure water. Regarding this collapse, the higher the aspect ratio (the ratio of height to width) of the microstructure, the easier it is to occur. For example, a microstructure with an aspect ratio of 3.5 or more is prone to collapse. Here, the maximum aspect ratio of the microstructure formed on the substrate W1 is set to be greater than 3.5. In addition, here, the minimum value of the interval between the microstructures formed on the substrate W1 is, for example, less than 50nm. The microstructure is also referred to as a pattern below.

[0046] In order to suppress this collapse, a waterproofing treatment is performed before the drying process. The waterproofing treatment is the following treatment: a treatment liquid containing a waterproofing agent is supplied to the main surface of the substrate W1, thereby forming a waterproof film (organic matter) on the surface of the pattern. In this way, the surface tension of the pure water acting on the pattern can be reduced, and the collapse of the pattern during the drying process can be suppressed. On the other hand, as a semiconductor product, such a waterproof film is not required. Therefore, it is desirable to remove the waterproof film after the drying process.

[0047] In addition, in treatments other than water-repellent treatment, organic matter may be formed or attached to the main surface of the substrate W1. For example, when an organic solvent such as IPA (isopropyl alcohol) is supplied to the main surface of the substrate W1, organic matter may remain on the main surface of the substrate W1. It is desirable to remove the organic matter after the treatment using the organic solvent.

[0048] The substrate processing device 10 performs organic matter removal processing on the substrate W1. Therefore, the substrate processing device 10 is an organic matter removal device. Figure 1 As shown, the substrate processing apparatus 10 includes a substrate holding unit 1 , an ultraviolet irradiator 2 , a gas supply unit 4 , and a control unit 7 .

[0049] <Substrate Holding Section>

[0050] The substrate holding part 1 is a component for holding the substrate W1. When the substrate W1 is a semiconductor substrate (i.e., a semiconductor wafer), the substrate W1 is in a substantially circular flat plate shape. The substrate holding part 1 holds the substrate W1 in a horizontal position with the thickness direction of the substrate W1 along the Z direction. The substrate W1 is held with the main surface on which the pattern is formed facing the Z axis side.

[0051] The substrate holding portion 1 has a substantially disk-shaped base 11, and has an upper surface 1a, a side surface 1b, and a lower surface 1c. The upper surface 1a is a surface facing the substrate W1. Figure 1 as well as Figure 2 In the example, a pair of grooves 111 are formed on the upper surface 1a. A manipulator of an external substrate handling robot (not shown) is inserted into the pair of grooves 111. That is, when the substrate W1 is transferred between the substrate holding part 1 and the external substrate handling robot (not shown), the manipulator of the substrate handling robot enters the pair of grooves 111. Thereby, it is possible to avoid the manipulator of the substrate handling robot from colliding with the substrate holding part 1. The side surface 1b connects the periphery of the upper surface 1a and the periphery of the lower surface 1c. The substrate W1 is placed on the upper surface 1a of the substrate holding part 1. The base 11 of the substrate holding part 1 can be formed of, for example, ceramics.

[0052] The substrate holding unit 1 can rotate the substrate W1 around a rotation axis Q1 parallel to the Z axis passing through the center of the substrate W1. Figure 1 In the example of , the substrate holding unit 1 further includes a rotating mechanism 12. The rotating mechanism 12 includes a motor (not shown) and rotates the base 11 around the rotation axis Q1. As a result, the substrate W1 held by the base 11 also rotates around the rotation axis Q1.

[0053] <Ultraviolet irradiator>

[0054] The ultraviolet irradiator 2 is provided on the +Z axis side of the substrate holding portion 1 and across the processing space H1 (see Figure 2 ) is opposite to the substrate W1. The ultraviolet irradiator 2 irradiates ultraviolet light to the main surface of the substrate W1 held by the substrate holding portion 1. As the ultraviolet irradiator 2, for example, a low-pressure mercury lamp, a high-pressure mercury lamp, an excimer lamp, a metal halide lamp, and a UV-LED (ultraviolet-Light Emitting Diode) light source are used. Figure 1 as well as Figure 2 In the example of FIG. 1 , a plurality of ultraviolet irradiators 2 are provided as the ultraviolet irradiators 2. In addition, a plurality of ultraviolet irradiators 2 are not necessarily provided, and only one ultraviolet irradiator may be provided.

[0055] Although the shape of the ultraviolet irradiator 2 is arbitrary, for example, the ultraviolet irradiator 2 may also be a point light source. In this case, a plurality of ultraviolet irradiators 2 are dispersed and arranged approximately evenly relative to the main surface of the substrate W1. Thus, the ultraviolet irradiator 2 can irradiate ultraviolet rays more evenly toward the entire main surface of the substrate W1.

[0056] Alternatively, the ultraviolet irradiator 2 may also be a linear light source. The ultraviolet irradiator 2 has a rod-like shape that is longer in the length direction. A plurality of ultraviolet irradiators 2 are arranged along the X direction with the length direction of the ultraviolet irradiator 2 along the Y direction. Alternatively, the ultraviolet irradiator 2 may also have a ring shape. A plurality of ultraviolet irradiators 2 are arranged in concentric circles. These ultraviolet irradiators 2 also irradiate ultraviolet rays toward the entire main surface of the substrate W1.

[0057] Alternatively, the ultraviolet irradiator 2 may also be a surface light source. In this case, the ultraviolet irradiator 2 extends along the XY plane and can be configured to be roughly parallel to the main surface of the substrate W1. The ultraviolet irradiator 2 may also cover the substrate W1 when viewed from above (i.e., when viewed from the Z-axis side). Thus, the ultraviolet irradiator 2 can irradiate the entire surface of the substrate W1 with ultraviolet rays.

[0058] A quartz glass 21 is provided on the -Z axis side of the ultraviolet irradiator 2 (specifically, between the ultraviolet irradiator 2 and the substrate W1). The quartz glass 21 is a plate-like body having heat resistance, corrosion resistance, and light transmittance to ultraviolet rays. The quartz glass 21 is provided approximately horizontally and is opposite to the ultraviolet irradiator 2 in the Z direction. The quartz glass 21 can protect the ultraviolet irradiator 2 in the atmosphere in the substrate processing device 10. The ultraviolet rays from the ultraviolet irradiator 2 are irradiated toward the main surface of the substrate W1 through the quartz glass 21.

[0059] The ultraviolet irradiator 2 irradiates the main surface of the substrate W1 with ultraviolet rays while the substrate W1 is being rotated by the rotation mechanism 12. This allows the main surface of the substrate W1 to be irradiated with ultraviolet rays more uniformly.

[0060] <Lifting Mechanism>

[0061] exist Figure 1 as well as Figure 2 In the example of FIG. 1 , the substrate holding portion 1 (more specifically, the base 11) is configured to be movable along the Z direction. More specifically, a lifting mechanism 13 is provided in the substrate processing apparatus 10. The lifting mechanism 13 can move the substrate holding portion 1 along the Z direction. For example, the lifting mechanism 13 is mounted on the lower surface 1c of the base 11 via the rotating mechanism 12. The lifting mechanism 13 can move the substrate holding portion 1 in the first position (refer to FIG. 1 ). Figure 2 ) and the second position (reference Figure 1 ), the first position is the position where the substrate holding part 1 is close to the ultraviolet irradiator 2, and the second position is the position where the substrate holding part 1 is away from the ultraviolet irradiator 2. As described later, the first position is the position of the substrate holding part 1 when the substrate W1 is treated with ultraviolet rays, and the second position is the position of the substrate holding part 1 when the substrate W1 is handed over. The distance between the substrate holding part 1 and the ultraviolet irradiator 2 in the first position is shorter than the distance between the substrate holding part 1 and the ultraviolet irradiator 2 in the second position. The lifting mechanism 13 can adopt, for example, an air cylinder, a ball screw mechanism, or a uniaxial stage. The lifting mechanism 13 can also be covered by bellows.

[0062] <Tube member>

[0063] exist Figure 1 as well as Figure 2 In the example of , a barrel member 3 is provided in the substrate processing device 10. The barrel member 3 has an inner peripheral surface 3a, an outer peripheral surface 3b, an upper surface 3c and a lower surface 3d, and has a cylindrical shape (for example, a cylindrical shape). The upper surface 3c is a surface for connecting the inner peripheral surface 3a and the outer peripheral surface 3b, and is a surface on the +Z axis side. The lower surface 3d is a surface for connecting the inner peripheral surface 3a and the outer peripheral surface 3b, and is a surface on the -Z axis side. The diameter of the inner peripheral surface 3a of the barrel member 3 is larger than the diameter of the side surface 1b of the substrate holding portion 1. Refer to Figure 2 When the substrate holding portion 1 is stopped at the first position, the inner peripheral surface 3 a of the cylinder member 3 surrounds the side surface 1 b of the substrate holding portion 1 .

[0064] In the state where the substrate holding portion 1 stops at the first position ( Figure 2), the ultraviolet irradiator 2 irradiates ultraviolet rays. Thus, the substrate W1 is treated with ultraviolet rays. On the other hand, when the substrate holding part 1 stops at the first position, the substrate W1 is surrounded by the quartz glass 21, the barrel member 3 and the substrate holding part 1. Therefore, the substrate W1 cannot be easily removed from the substrate holding part 1 in this state.

[0065] Therefore, the lifting mechanism 13 moves the substrate holding portion 1 to the second position ( Figure 1 ). As a result, the substrate holding portion 1 retreats from the inside of the inner peripheral surface 3a of the barrel member 3 in the direction away from the ultraviolet irradiator 2. In the second position, the substrate W1 is located on the -Z axis side relative to the lower surface 3d of the barrel member 3. Therefore, the substrate W1 is not hindered by the barrel member 3 and is carried out from the substrate processing device 10 by a substrate transport robot (not shown). On the contrary, when the substrate holding portion 1 is stopped at the second position, the substrate transport robot places the substrate W1 on the substrate holding portion 1.

[0066] <Removal of organic matter>

[0067] As described above, the ultraviolet irradiator 2 irradiates ultraviolet light when the substrate holding portion 1 is in the first position. The ultraviolet light is irradiated to the main surface of the substrate W1 held by the substrate holding portion 1. Since the energy of the ultraviolet light photons is large and can cut the molecular bonds of organic matter, the organic matter (such as a waterproof film) formed on the main surface of the substrate W1 can be decomposed and removed.

[0068] However, it is difficult for the ultraviolet rays to enter the −Z axis side through the gaps between the patterns formed on the main surface of the substrate W1 . Figure 3 The simulation result shows the intensity distribution of ultraviolet rays near the pattern P1 on the main surface of the substrate W1. The pattern P1 can be assumed to be formed by a rectangular silicon P11 as a main body and a silicon oxide film P12 formed on the surface of the silicon P11. Figure 3 In the example of FIG. 1 , the intensity distribution of ultraviolet light is shown when the wavelength of ultraviolet light is 172 nm, the height and width of pattern P1, and the interval between patterns P1 are 200 nm, 20 nm, and 10 nm, respectively. Figure 3 2 shows the intensity of ultraviolet rays near two patterns P1 , but the actual simulation is performed on a structure in which three or more patterns P1 are arranged side by side at the same interval (pitch) in the horizontal direction.

[0069] exist Figure 3 In the diagram, the intensity of ultraviolet rays is represented by contour lines C1 to C6. The smaller the number at the end of the symbol, the higher the intensity of ultraviolet rays. That is, contour line C1 represents the highest intensity ultraviolet rays, and contour line C6 represents the lowest intensity ultraviolet rays. Figure 3In the example of FIG. 1 , the shadow of the sand is given to the area divided by the contour lines C1 to C6. The shadow of the sand given to each area is denser as the intensity of the ultraviolet rays is higher.

[0070] like Figure 3 As shown in the example, the intensity of ultraviolet light has the following trend: although it becomes stronger and weaker as it moves toward the -Z axis side, it decreases as it moves toward the -Z axis side. The reason why the intensity of ultraviolet light decreases as it moves toward the -Z axis side is that ultraviolet light is difficult to diffract. In addition, the reason why the intensity of ultraviolet light becomes stronger and weaker is that ultraviolet light that has entered between patterns is reflected and interferes with each other.

[0071] In the region where the ultraviolet light intensity is high, the ultraviolet light can effectively act on the organic matter formed on the side wall of the pattern P1, thereby fully removing the organic matter. On the other hand, in the region where the ultraviolet light intensity is low (e.g., the region indicated by the contour lines C5 and C6), the ultraviolet light cannot fully remove the organic matter formed on the side wall of the pattern P1. The organic matter formed on the side wall of the pattern P1 is hereinafter referred to as the organic matter between the patterns P1.

[0072] Therefore, in this embodiment, the decomposition function of organic matter caused by ozone is utilized. The ozone is generated by irradiating the air (containing oxygen) in the processing space H1 with ultraviolet rays. Specifically, when the ultraviolet rays (UV) irradiate the oxygen molecules (O2) in the processing space H1, oxygen atoms (O) are generated by the dissociation reaction shown in the following formula (1). Then, ozone (O3) is generated by the three-body reaction of oxygen atoms (O), oxygen molecules (O2) and surrounding gas (M) shown in the following formula (2).

[0073] O2+UV→O+O (1)

[0074] O2+O+M→O3+M (2)

[0075] As long as the ozone acts on the organic matter on the main surface of the substrate W1, the organic matter can be decomposed and removed. In order to make the ozone effectively act on the organic matter between the patterns P1 of the substrate W1, it is desirable to generate ozone near the main surface of the substrate W1. The reason for this is that since the ozone generated near the main surface of the substrate W1 is close to the patterns P1, it is highly likely to enter between the patterns P1, thereby easily acting on the organic matter between the patterns P1.

[0076] In addition, as can be understood from formula (1), the amount of ozone generated increases as more oxygen molecules and higher ultraviolet intensity are present. Therefore, first, it is considered to increase the number of oxygen molecules in the processing space H1. That is, to increase the oxygen concentration in the processing space H1. In addition, here, since the width of the processing space H1 in the Z direction is narrow to several mm, the oxygen concentration in the processing space H1 can be considered to be roughly uniform.

[0077] On the other hand, the intensity of the ultraviolet light on the main surface of the substrate W1 decreases as the oxygen concentration in the processing space H1 increases. This is because the ultraviolet light is absorbed by the oxygen molecules through the dissociation reaction of formula (1). That is, when the oxygen concentration in the processing space H1 increases, most of the ultraviolet light is absorbed by the oxygen molecules before reaching the main surface of the substrate W1. Therefore, the intensity of the ultraviolet light on the main surface of the substrate W1 decreases.

[0078] As described above, when the oxygen concentration in the processing space H1 is increased, the oxygen concentration near the main surface of the substrate W1 increases, while the intensity of ultraviolet rays on the main surface of the substrate W1 decreases. Therefore, there is a situation where the amount of ozone generated near the main surface of the substrate W1 decreases due to the increase in the oxygen concentration in the processing space H1.

[0079] Here, the relationship between the oxygen concentration in the processing space H1, the illumination of ultraviolet rays, and the generation rate of ozone is considered. It is believed that the generation rate of oxygen atoms caused by the dissociation reaction of formula (1) is proportional to the illumination of ultraviolet rays. In addition, it is believed that the oxygen atoms are highly reactive, and the generated oxygen atoms react rapidly with oxygen molecules by the three-body reaction of formula (2) and become ozone. Therefore, when the partial pressure x0 of oxygen molecules and the partial pressure x of oxygen atoms just before ultraviolet irradiation are used, the generation rate v of ozone can be expressed by the following formula.

[0080] v=k1×(x-x0)×2x (3)

[0081] k1 is a proportionality constant. Since it is considered that the partial pressure x of oxygen atoms is proportional to the illuminance I of ultraviolet rays and x / x0 is much smaller than 1, the equation (3) can be transformed into the equation (4).

[0082] v=k2×x0×I (4)

[0083] According to the formula (4), the ozone generation rate v is considered to be proportional to the product of the oxygen concentration and the ultraviolet irradiance.

[0084] Table 1 below shows the illuminance of ultraviolet rays on the main surface of the substrate W1 and the generation rate of ozone generated on the main surface of the substrate W1 when the oxygen concentration in the processing space H1 is different.

[0085] [Table 1]

[0086]

[0087] The oxygen concentration and ultraviolet irradiance in Table 1 are experimental results. According to Table 1, when the oxygen concentration in the processing space H1 is 20.1 vol%, the ultraviolet irradiance on the main surface of the substrate W1 is 4.7 mW / cm 2 Since the oxygen concentration in the processing space H1 is considered to be uniform, the oxygen concentration on the main surface of the substrate W1 is also 20.1 vol%. Therefore, the generation rate of ozone generated on the main surface of the substrate W1 at this time is proportional to the oxygen concentration (20.1 vol%) and the illumination (4.7 mw / cm 2 In Table 1, the ozone generation rate at this time is normalized to 1.

[0088] According to Table 1, when the oxygen concentration is 4.4 vol%, the illuminance of ultraviolet light on the main surface of the substrate W1 is 23.1 mW / cm 2 That is, it can be seen that the illumination of ultraviolet rays on the main surface of the substrate W1 is increased by reducing the oxygen concentration. Moreover, the generation rate of ozone generated on the main surface of the substrate W1 at this time is 1.08. That is, compared with the case where the oxygen concentration in the processing space H1 is 20.1 vol%, the amount of ozone generated on the main surface of the substrate W1 is larger when the oxygen concentration is 4.4 vol%.

[0089] Therefore, the decomposition performance of organic matter by ozone is greater when the oxygen concentration is 4.4 vol % than when the oxygen concentration in the processing space H1 is 20.1 vol %.

[0090] However, when the oxygen concentration is further reduced to less than 4.4 vol%, the amount of oxygen molecules that are the source of ozone is further reduced, so the ozone generation rate is lower than 1. Therefore, the decomposition performance by ozone is lower than the decomposition performance when the oxygen concentration is 20.1 vol%.

[0091] Figure 4 This is a graph showing the relationship between the degree of organic matter removal and oxygen concentration. Figure 4 In the embodiment, the contact angle of the liquid when the liquid is applied to the substrate W1 is used as an index for indicating the degree of removal of the organic matter. The contact angle indicates that the smaller the value of the contact angle, the greater the degree of removal of the organic matter. Figure 4 The following is an experimental result when the substrate processing apparatus 10 irradiates the main surface of the substrate W1 with ultraviolet rays for a predetermined irradiation time.

[0092] like Figure 4 As shown in the example, it can be seen that the waveform of the contact angle has a downward convex shape and there is an optimal range of oxygen concentration. Figure 4In the example shown in FIG. 1 , the baseline A1 is shown. The baseline A1 represents the contact angle when the liquid is applied to the substrate W1 on which no organic matter is formed on the main surface. Therefore, when the contact angle becomes less than the baseline A1, the organic matter on the substrate W1 can be properly removed by ultraviolet irradiation treatment. Figure 4 According to the graph of FIG. 1 , when the oxygen concentration in the processing space H1 is in the range of 0.3 vol% to 8.0 vol%, the contact angle becomes smaller than the base line A1. Therefore, when the oxygen concentration is in this range, the organic matter can be appropriately removed.

[0093] In addition, the reason why the degree of removal of organic matter is low in the range of oxygen concentration higher than 8.0 vol% is considered as follows. That is, when the oxygen concentration is high, most of the ultraviolet rays are absorbed by the oxygen molecules in the processing space H1 before reaching the main surface of the substrate W1, and the intensity of the ultraviolet rays on the main surface of the substrate W1 is reduced. Due to the lack of ultraviolet rays, the generation rate of ozone generated near the main surface of the substrate W1 is reduced, and the decomposition performance of organic matter caused by ozone cannot be effectively exerted.

[0094] On the other hand, the reason why the degree of removal of organic matter is low in the range of oxygen concentration lower than 0.3 vol% is considered as follows. That is, when the oxygen concentration is low, the amount of oxygen molecules in the processing space H1 is small, so even if the intensity of ultraviolet rays is high, the amount of ozone generated is still small. Therefore, the amount of ozone entering between the patterns P1 is small, and the organic matter is not completely removed and remains.

[0095] Therefore, in the present embodiment, the oxygen concentration in the processing space H1 is adjusted to a predetermined concentration range (0.3 vol % to 8.0 vol %) during at least a part of the ultraviolet irradiation period during which ultraviolet rays are irradiated.

[0096] <Gas Supply Section>

[0097] The oxygen concentration in the processing space H1 is adjusted by the gas supply unit 4. The gas supply unit 4 supplies gas to the processing space H1 between the ultraviolet irradiator 2 and the substrate W1, and adjusts the oxygen concentration in the processing space H1 to a predetermined concentration range. The gas supplied by the gas supply unit 4 is hereinafter referred to as an adjustment gas. As the adjustment gas, for example, an inert gas (for example, nitrogen or argon) can be used.

[0098] exist Figure 1 as well as Figure 2 In the example of FIG. 1 , the gas supply unit 4 supplies the adjustment gas to the processing space H1 via the through holes 321 and 322 formed in the cylinder member 3. The through holes 321 and 322 are first described below. The through holes 321 and 322 penetrate the cylinder member 3 and communicate with the space between the quartz glass 21 and the substrate W1. Figure 1 as well as Figure 2 In the example of, one end of the through holes 321, 322 opens at the upper surface 3c of the barrel member 3. Hereinafter, one end of the through holes 321, 322 is also referred to as the openings (gas supply openings) 321a, 322a. At the position where the openings 321a, 322a are formed, the upper surface 3c of the barrel member 3 is opposed to the peripheral portion of the quartz glass 21 via a gap. The openings 321a, 322a are connected to the processing space H1. That is, the through holes 321, 322 are connected to the processing space H1. When viewed from above, the openings 321a, 322a are formed at positions facing each other via the central axis of the inner peripheral surface 3a.

[0099] exist Figure 1 as well as Figure 2 In the example of , the gas supply unit 4 includes a pipe 41, a supply valve 42, and a gas supply source 43. The pipe 41 includes a common pipe 411 and branch pipes 412 and 413. One end of the branch pipe 412 is connected to the other end 321b of the through hole 321, and the other end of the branch pipe 412 is connected to one end of the common pipe 411. The other end of the common pipe 411 is connected to the gas supply source 43. One end of the branch pipe 413 is connected to the other end 322b of the through hole 322, and the other end of the branch pipe 413 is connected to one end of the common pipe 411. The gas supply source 43 supplies the adjustment gas to the common pipe 411. The adjustment gas is supplied from the common pipe 411 to the processing space H1 via the branch pipes 412, 413 and the through holes 321 and 322.

[0100] The supply valve 42 is provided in the middle of the common pipe 411, and switches the opening and closing of the flow path in the common pipe 411. The supply valve 42 is controlled by the control unit 7. The supply valve 42 is a valve capable of adjusting the flow rate of the adjustment gas toward the processing space H1.

[0101] <Confined Space>

[0102] The substrate processing apparatus 10 may also form a closed space. Figure 1 as well as Figure 2In the example of, the top member 52, the barrel member 3, the partition wall 5 and the bottom 51 are connected to each other and form a closed space. The peripheral portion of the lower surface of the top member 52 has a protruding shape protruding on the +Z axis side (the side of the barrel member 3). On the contrary, the central portion of the lower surface of the top member 52 has a concave shape that is recessed on the -Z axis side. A plurality of ultraviolet irradiators 2 and quartz glass 21 are arranged inside the concave shape. The side surface of the quartz glass 21 abuts against the inner surface of the protruding shape of the top member 52. The portion on the outer peripheral side of the upper surface 3c of the barrel member 3 is connected to the protruding shape of the top member 52 in the Z direction. The openings 321a and 322a of the through holes 321 and 322 are formed in the portion on the inner peripheral side of the upper surface 3c, and face the lower surface of the quartz glass 21 via a gap in the Z direction. The partition wall 5 is connected to the lower surface 3d of the barrel member 3. The partition wall 5 extends in the Z direction and is connected to the bottom 51. A plurality of ultraviolet irradiators 2 , quartz glass 21 , substrate holding unit 1 , and lifting mechanism 13 are accommodated in a sealed space formed by the ceiling member 52 , the cylindrical member 3 , the partition wall 5 , and the bottom 51 .

[0103] <Exhaust>

[0104] The partition wall 5 has a through hole 53 for exhaust. The through hole 53 is connected to the exhaust unit 61. The exhaust unit 61 includes a pipe 611 connected to the through hole 53. The gas inside the substrate processing apparatus 10 is exhausted to the exhaust unit 61 outside through the pipe 611.

[0105] <Shutter>

[0106] A shutter door (not shown) serving as an entrance and exit for the substrate W1 is provided on the partition wall 5. The shutter door is opened, thereby connecting the interior and the exterior of the substrate processing apparatus 10. The substrate transport robot can carry the substrate W1 into the interior of the substrate processing apparatus 10 or carry the substrate W1 out of the interior of the substrate processing apparatus 10 through the opened shutter door.

[0107] <Control Unit>

[0108] The control unit 7 integrally controls the substrate processing apparatus 10. Specifically, the control unit 7 controls the ultraviolet irradiator 2, the rotating mechanism 12, the lifting mechanism 13, the supply valve 42 of the gas supply unit 4, the shutter, and the substrate transport robot.

[0109] The control unit 7 may also be an electronic circuit having, for example, a data processing device and a storage medium. The data processing device may also be, for example, a calculation processing device such as a CPU (Central Processor Unit). The storage unit may also have a non-temporary storage medium (such as a ROM (Read Only Memory) or a hard disk) and a temporary storage medium (such as a RAM (Random Access Memory)). A program for specifying the processing performed by the control unit 7 may also be stored in a non-temporary storage medium. The processing device executes the program, whereby the control unit 7 can perform the processing specified by the program. Of course, part or all of the processing performed by the control unit 7 may also be executed by hardware.

[0110] The controller 7 controls the gas supply unit 4 to supply the adjustment gas so that the oxygen concentration in the processing space H1 is within the range of 0.3 vol% to 8.0 vol%, and simultaneously controls the ultraviolet irradiator 2 to irradiate the main surface of the substrate W1 with ultraviolet rays. An example of the operation of the substrate processing apparatus 10 will be described in detail below.

[0111] <Operation of Substrate Processing Apparatus>

[0112] Figure 5 1 is a flowchart showing an example of the operation of the substrate processing apparatus 10. The lifting mechanism 13 initially stops the substrate holding portion 1 at the second position ( Figure 1 ). In addition, as an example, exhaust is always performed by the exhaust unit 61. In step S1 (substrate holding process), the control unit 7 opens the shutter door, controls the substrate transport robot to place the substrate W1 on the substrate holding unit 1, and then closes the shutter door. A microstructure is formed on the main surface of the +Z axis side of the substrate W1, and an organic substance (such as a waterproof film) exists on the surface of the microstructure. The substrate holding unit 1 holds the substrate W1.

[0113] Next, in step S2, the control unit 7 controls, for example, the supply valve 42 of the gas supply unit 4 to start supplying the adjustment gas. As a result, the adjustment gas is ejected from the openings 321a and 322a, respectively, and at least a portion of the air in the processing space H1 is pushed out of the processing space H1 by the adjustment gas and exhausted to the exhaust unit 61. Specifically, the air in the processing space H1 flows toward the -Z axis side in the space between the inner circumferential surface 3a of the cylinder member 3 and the side surface 1b of the base 11, and is exhausted to the exhaust unit 61 from the through hole 53. As a result, at least a portion of the air in the processing space H1 is replaced with the adjustment gas. Here, as an example, nitrogen or argon is used as the adjustment gas. Since a portion of the air in the processing space H1 is replaced with the adjustment gas, the oxygen concentration in the processing space H1 is reduced. In addition, the execution order of steps S1 and S2 may be reversed, and steps S1 and S2 may also be executed in parallel.

[0114] Next, in step S3, the control unit 7 controls the lifting mechanism 13 to make the substrate holding unit 1 (base 11) approach the ultraviolet irradiator 2 and stop at the first position. At this time, the distance between the ultraviolet irradiator 2 and the substrate W1 is set to, for example, about 2 mm to 3 mm. In addition, step S3 does not necessarily need to be performed after step S2, as long as it is performed after step S1.

[0115] The control unit 7 controls the supply valve 42 to control the flow rate of the adjustment gas so that the oxygen concentration in the processing space H1 when the susceptor 11 is stopped at the first position is within a predetermined concentration range. The flow rate of the adjustment gas may be preset, for example, through simulation or experiment.

[0116] Next, in step S4, the control unit 7 controls the rotating mechanism 12 to rotate the substrate W1. Specifically, the control unit 7 rotates the substrate holding unit 1 (base 11). Thus, the substrate W1 rotates in a horizontal plane. In addition, step S4 does not necessarily need to be performed after step S3, and can be performed after step S1.

[0117] Next, in step S5, the control unit 7 determines whether the atmosphere replacement of the processing space H1 is completed. In other words, the control unit 7 determines whether the oxygen concentration in the processing space H1 is within a predetermined concentration range. This judgment can also be made based on whether the elapsed time from step S3 is longer than a first predetermined time that is set in advance. The timing of the elapsed time can be performed by a timing circuit such as a time measuring circuit. The first predetermined time is the time required for the oxygen concentration to become within a predetermined concentration range, and can be pre-set through simulation or experiment. The control unit 7 determines that the oxygen concentration in the processing space H1 has become within the predetermined concentration range when the elapsed time from step S3 is longer than the first predetermined time.

[0118] When the control unit 7 determines that the oxygen concentration in the processing space H1 is outside the predetermined concentration range, the control unit 7 executes step S5 again. On the other hand, when the control unit 7 determines that the oxygen concentration in the processing space H1 is within the predetermined concentration range, the control unit 7 causes the ultraviolet irradiator 2 to irradiate ultraviolet rays in step S6.

[0119] Ultraviolet rays are irradiated by the ultraviolet irradiator 2 to perform a treatment for removing organic matter using ultraviolet rays on the substrate W1. Specifically, first, the ultraviolet rays act on organic matter (such as a waterproof film) present on the main surface of the substrate W1, thereby decomposing and removing the organic matter. Second, the ultraviolet rays are absorbed by oxygen molecules in the processing space H1 to generate ozone, which decomposes and removes the organic matter present on the main surface of the substrate W1.

[0120] As described above, since the oxygen concentration in the processing space H1 is adjusted to a predetermined concentration range, a large amount of ozone is generated near the main surface of the substrate W1. The ozone easily acts on the organic matter between the patterns P1 and can also decompose and remove the organic matter between the patterns P1.

[0121] Next, in step S7, the control unit 7 determines whether the processing of the substrate W1 should be terminated. For example, the control unit 7 may determine that the processing should be terminated when the elapsed time from step S6 exceeds the second predetermined time. When it is determined that the processing should not be terminated, the control unit 7 executes step S7 again. On the other hand, when it is determined that the processing should be terminated, the control unit 7 stops the ultraviolet irradiator 2 from irradiating ultraviolet rays in step S8. Thus, the removal process of organic matter using ultraviolet rays is terminated. The ultraviolet irradiation period is the period from step S6 to step S8, and the process from step S6 to step S8 is equivalent to the ultraviolet irradiation process.

[0122] After that, the control unit 7 controls the rotation mechanism 12 and the supply valve 42 to stop the rotation of the substrate W1 and the supply of nitrogen. Next, the control unit 7 controls the lifting mechanism 13 to lower the substrate holder 1 to the second position and open the shutter. The substrate transport robot carries out the substrate W1 with organic matter removed from the substrate holder 1.

[0123] As described above, according to the substrate processing device 10, during the ultraviolet irradiation period, the oxygen concentration in the processing space H1 is maintained within a predetermined concentration range (above 0.3 vol% and below 8.0 vol%). Therefore, the organic matter between the patterns P1 on the main surface of the substrate W1 can also be properly removed. The reason for this is that since the oxygen concentration is maintained within a predetermined concentration range, a sufficient amount of ozone can be generated near the main surface of the substrate W1. That is, since sufficient ozone is generated at a position where it can easily enter between the patterns P1, the ozone easily acts on the organic matter between the patterns P1, and the organic matter between the patterns P1 can also be properly removed.

[0124] In addition, in the above example, the ultraviolet irradiation is started while the oxygen concentration in the processing space H1 is maintained within a predetermined concentration range (steps S5, S6). That is, the oxygen concentration is adjusted to within a predetermined concentration range during the entire period of ultraviolet irradiation. However, it is not limited to this. For example, the oxygen concentration may be brought to within a predetermined concentration range after the ultraviolet irradiation is started. In short, as long as the control unit 7 adjusts the oxygen concentration to within a predetermined concentration range during at least a portion of the ultraviolet irradiation period. The reason for this is that organic matter in the gaps between the patterns P1 can be removed during at least a portion of the ultraviolet irradiation period.

[0125] <Range of oxygen concentration>

[0126] like Figure 4 As shown, the waveform of the contact angle is convex downward, and the contact angle is approximately constant (minimum value) in the range of oxygen concentration of 0.6 vol% to 7.0 vol%. Therefore, the range of 0.6 vol% to 7.0 vol% can also be used as the predetermined concentration range. Thus, organic matter on the main surface of the substrate W1 can be more appropriately removed.

[0127] Second embodiment

[0128] Figure 6 FIG. 1 is a diagram schematically showing an example of the structure of a substrate processing apparatus 10A. Figure 6 The structure of the substrate processing apparatus 10A is shown in a state where the substrate holding portion 1 is stopped at the first position. The substrate processing apparatus 10A has the same structure as the substrate processing apparatus 10 except that the oxygen concentration sensor 9 is not provided.

[0129] The oxygen concentration sensor 9 detects the oxygen concentration in the processing space H1. Any detection method can be adopted as the detection method of the oxygen concentration sensor 9. Figure 6 In the example of , the oxygen concentration sensor 9 is arranged to avoid the space directly above the substrate W1 held by the substrate holding portion 1. If it is assumed that the oxygen concentration sensor 9 is arranged in the space directly above the substrate W1, the ultraviolet rays from the ultraviolet irradiator 2 will irradiate the oxygen concentration sensor 9 and prevent the ultraviolet rays from irradiating the main surface of the substrate W1. In contrast, in the substrate processing device 10A, since the oxygen concentration sensor 9 is arranged to avoid the space directly above the substrate W1, the ultraviolet rays from the ultraviolet irradiator 2 can properly irradiate the main surface of the substrate W1.

[0130] The oxygen concentration sensor 9 may be provided on the downstream side of the flow of the adjustment gas relative to the processing space H1. Figure 6In the example, the oxygen concentration sensor 9 is provided at a position opposite to the inner peripheral surface 3a of the cylinder member 3. More specifically, the oxygen concentration sensor 9 is located between the inner peripheral surface 3a of the cylinder member 3 and the side surface 1b of the base 11 when the base 11 of the substrate holding portion 1 is located at the first position.

[0131] The gas in the processing space H1 flows through the flow path between the inner peripheral surface 3a of the cylinder member 3 and the side surface 1b of the base 11 and is exhausted from the exhaust portion 61. Since it can be considered that the oxygen concentration of the gas flowing in the flow path is substantially equal to the oxygen concentration in the processing space H1, the oxygen concentration sensor 9 can detect the oxygen concentration in the processing space H1.

[0132] The oxygen concentration sensor 9 is electrically connected to the control unit 7. The oxygen concentration sensor 9 outputs the detected oxygen concentration value to the control unit 7. The control unit 7 controls the flow rate of the adjustment gas supplied from the gas supply unit 4 so that the oxygen concentration value detected by the oxygen concentration sensor 9 is within a predetermined concentration range. The control unit 7 performs oxygen concentration control during at least a portion of the period during which the ultraviolet irradiator 2 irradiates ultraviolet rays.

[0133] An example of the operation of the substrate processing apparatus 10A is Figure 5 However, the control unit 7 performs the above oxygen concentration control during the execution of steps S6 to S8. As a more specific example, a target value for the oxygen concentration value may also be pre-set. The target value is a value within a predetermined concentration range. Figure 7 1 is a functional block diagram showing an example of the electrical configuration of the substrate processing apparatus 10A. The control unit 7 receives an oxygen concentration value and a target value from the oxygen concentration sensor 9. The control unit 7 controls the supply valve 42 so that the oxygen concentration value approaches the target value.

[0134] For example, when the oxygen concentration value is lower than the target value, the control unit 7 controls the supply valve 42 to reduce the flow rate of the adjustment gas. When the flow rate of the adjustment gas flowing into the processing space H1 is reduced, the non-processing space H2 (see Figure 6 ) will be partially introduced into the processing space H1. Since the oxygen concentration in the non-processing space H2 is higher than that in the processing space H1, the oxygen concentration in the processing space H1 will increase. That is, the oxygen concentration in the processing space H1 can be brought close to the target value.

[0135] On the other hand, the control unit 7 can control the supply valve 42 to increase the flow rate of the adjustment gas when the oxygen concentration value is higher than the target value. As a result, since more air in the processing space H1 is replaced with the adjustment gas, the oxygen concentration in the processing space H1 is reduced. Therefore, the oxygen concentration in the processing space H1 can be brought close to the target value.

[0136] As described above, according to the substrate processing apparatus 10A, the control unit 7 controls the adjustment gas so that the oxygen concentration value detected by the oxygen concentration sensor 9 is within the predetermined concentration range, so that the oxygen concentration in the processing space H1 can be more reliably adjusted to be within the predetermined concentration range.

[0137] Furthermore, in the above example, since the oxygen concentration sensor 9 is located on the downstream side of the flow of the adjustment gas relative to the processing space H1 , it does not prevent the ultraviolet irradiator 2 from irradiating the substrate W1 with ultraviolet rays.

[0138] Figure 8 It is a diagram schematically showing an example of the structure of the substrate processing apparatus 10B. Figure 8 The structure of the substrate processing apparatus 10B is shown in a state where the substrate holding unit 1 is stopped at the first position. The substrate processing apparatus 10B has the same structure as the substrate processing apparatus 10A except for the structure of the gas supply unit 4 .

[0139] Figure 8 The illustrated gas supply unit 4 supplies inert gas and oxygen as adjustment gas to the processing space H1. As a specific example, the gas supply unit 4 includes a pipe 41, supply valves 42 and 44, a gas supply source 43, and an oxygen supply source 45. The pipe 41 also includes a common pipe 411 and branch pipes 412, 413, and 414.

[0140] One end of the branch pipe 414 is connected to the middle of the common pipe 411 on the downstream side of the supply valve 42, and the other end of the branch pipe 414 is connected to the oxygen supply source 45. The supply valve 44 is provided in the middle of the branch pipe 414, and switches the opening and closing of the flow path in the branch pipe 414. The supply valve 44 is controlled by the control unit 7. The supply valve 44 is a valve that can adjust the flow rate of oxygen in the branch pipe 414.

[0141] By opening both the supply valves 42 and 44, a mixed gas of inert gas and oxygen is ejected from the openings 321a and 322a as the adjustment gas into the processing space H1. The controller 7 controls the supply valves 42 and 44 to adjust the flow rates of the inert gas and oxygen, thereby adjusting the oxygen concentration of the adjustment gas.

[0142] The control unit 7 controls the supply valves 42 and 44 based on the oxygen concentration value detected by the oxygen concentration sensor 9. Specifically, the control unit 7 controls the supply valves 42 and 44 (i.e., the flow rates of the inert gas and oxygen) so that the oxygen concentration value detected by the oxygen concentration sensor 9 is maintained within a predetermined concentration range. The control unit 7 performs this oxygen concentration control during at least a portion of the period during which the ultraviolet irradiator 2 irradiates the ultraviolet rays.

[0143] An example of the operation of the substrate processing apparatus 10A is Figure 5The flowchart is the same as that of . However, the control unit 7 performs the above-mentioned oxygen concentration control in the execution process of steps S6 to S8. For example, the control unit 7 controls the supply valves 42 and 44 to reduce the oxygen concentration of the adjustment gas when reducing the oxygen concentration in the processing space H1. As a specific example, the control unit 7 controls the supply valves 42 and 44 to increase the flow rate of the inert gas while reducing the flow rate of oxygen. For example, the control unit 7 can control the flow rate of oxygen to zero. Thereby, the oxygen concentration in the processing space H1 can be rapidly reduced.

[0144] On the other hand, when increasing the oxygen concentration in the processing space H1, the control unit 7 controls the supply valves 42 and 44 to increase the oxygen concentration of the adjustment gas. As a specific example, the control unit 7 controls the supply valves 42 and 44 to reduce the flow rate of the inert gas and increase the flow rate of oxygen. In this way, the oxygen concentration in the processing space H1 can be rapidly increased.

[0145] As described above, according to the substrate processing apparatus 10B, the gas supply unit 4 also supplies oxygen. Thus, by adjusting the oxygen concentration of the adjustment gas as described above, the change rate of the oxygen concentration in the processing space H1 can be increased. Therefore, the processing throughput can be increased.

[0146] Third embodiment

[0147] If referenced Figure 3 As described above, the intensity of ultraviolet light varies in the depth direction of the pattern P1. Therefore, in the gaps between the patterns P1, ozone is easily generated in the region where the intensity of ultraviolet light is high, and is difficult to generate in the region where the intensity of ultraviolet light is low. Therefore, in the third embodiment, ozone is generated in a wider region in the gaps between the patterns P1.

[0148] Fig. 9 10C is a diagram schematically showing an example of the structure of a substrate processing apparatus 10C. The substrate processing apparatus 10C has the same structure as the substrate processing apparatus 10 except for the structure of the ultraviolet irradiator 2.

[0149] A plurality of ultraviolet irradiators 2 are provided in the substrate processing device 10C. The plurality of ultraviolet irradiators 2 include two types of ultraviolet irradiators 2a and 2b that irradiate ultraviolet rays with different spectra (spectral distribution) from each other. Here, the definition of "different spectra" is explained. Different spectra refer to the spectrum of light output from the light source having different peak wavelengths. The so-called peak wavelength refers to the wavelength when the light intensity takes a peak value in the spectrum. There may be multiple peak wavelengths in the spectrum of a light source. For example, the peak wavelength of ultraviolet rays irradiated from a low-pressure mercury lamp is multiple, for example, 185nm and 254nm. The peak wavelength will also be referred to as the wavelength below.

[0150] As the plurality of ultraviolet irradiators 2, light sources such as low-pressure mercury lamps, high-pressure mercury lamps, excimer lamps, metal halide lamps, and UV-LEDs can be used. The spectra of light emitted from these various light sources are different from each other.

[0151] In addition, even for the same type of light source, the spectrum may be different. For example, an excimer lamp has a quartz tube filled with a discharge gas (such as a rare gas or a rare gas halogen compound) and a pair of electrodes. The discharge gas is present between the pair of electrodes. A high frequency-high voltage is applied between the pair of electrodes, whereby the discharge gas is excited to become a quasi-molecular state. The discharge gas generates ultraviolet rays when it returns from the excimer state to the base state. The spectrum of the ultraviolet rays irradiated from the excimer lamp may be different depending on the type of discharge gas, etc. Specifically, the peak wavelength of the ultraviolet rays irradiated from the excimer lamp may take values ​​such as 126nm, 146nm, 172nm, 222nm or 308nm, depending on the type of discharge gas, etc.

[0152] That is, as the plurality of ultraviolet irradiators 2, a plurality of types of light sources such as a low-pressure mercury lamp and an excimer lamp may be used, or light sources of the same type but with different spectra may be used.

[0153] An example of the operation of the substrate processing apparatus 10C is Figure 5 However, in step S6, the control unit 7 causes both the ultraviolet irradiators 2a and 2b to irradiate ultraviolet rays.

[0154] Since the peak wavelength of the first ultraviolet rays irradiated by the ultraviolet irradiator 2a is different from the peak wavelength of the second ultraviolet rays irradiated by the ultraviolet irradiator 2b, the intensity cycle of the first ultraviolet rays in the gaps between the patterns P1 is different from the intensity cycle of the second ultraviolet rays in the gaps between the patterns P1.

[0155] Fig.10 as well as Fig.11 This is a diagram showing an example of the intensity of ultraviolet rays near the pattern P1 of the substrate W1 for each wavelength. Fig.10 as well as Fig.11 Indicates the simulation results. Fig.10 The left side of the paper shows the results when ultraviolet light with a wavelength of λa (=126nm) is used. Fig.10 The right side of the paper shows the results when ultraviolet light with a wavelength of λb (=172nm) was used. Fig.10 In the example, the intensity of ultraviolet rays is represented by contour lines C1 to C4. The smaller the number of the symbol of the intensity of ultraviolet rays represented by contour lines C1 to C4, the higher the intensity. That is, the intensity represented by contour line C1 is the highest, the intensity represented by contour line C4 is the lowest, and the intensity represented by contour line C2 is higher than the intensity represented by contour line C3.

[0156] exist Fig.10 as well as Fig.11 In the example, the height and width of pattern P1 are set to 200 nm and 10 nm respectively. Fig.10 The intensity of ultraviolet light near one pattern P1 is shown in FIG. 1 , but the actual simulation is performed for a structure in which multiple patterns P1 are arranged at the same interval (pitch) in the horizontal direction. In this simulation, the pitch of the pattern P1 is set to 50 nm. Therefore, the width of the gap between the patterns P1 is 40 nm.

[0157] exist Fig.11 In the figure, the intensity of ultraviolet light on the side of pattern P1 is shown for the depth direction (Z direction) of the gap. The position in the depth direction of the gap is referred to as the depth position. In addition, the depth position of the upper end (the end on the +Z axis side) of pattern P1 is defined as 0nm. Since the height of pattern P1 is 200nm, the depth position of the lower end (the end on the -Z axis side) of pattern P1 is 200nm. Fig.11 In FIG. 1 , the intensity of the ultraviolet light having a wavelength λa from the ultraviolet irradiator 2a is indicated by a solid line, and the intensity of the ultraviolet light having a wavelength λb from the ultraviolet irradiator 2b is indicated by a dotted line.

[0158] like Fig.10 as well as Fig.11 As shown in FIG. 1 , the intensity of the ultraviolet light with wavelength λa shows the following tendency: as the depth position moves from the upper end of pattern P1 toward the lower end, even if the intensity of the ultraviolet light with wavelength λa repeatedly increases and decreases, the peak value (maximum value) gradually decreases. On the other hand, although the intensity of the ultraviolet light with wavelength λb repeatedly increases and decreases as the depth position moves from the upper end of pattern P1 toward the lower end, the peak value hardly decreases. This is because since wavelength λb is longer than wavelength λa, ultraviolet light with wavelength λb is easier to enter the gaps between patterns P1 than ultraviolet light with wavelength λa.

[0159] The increase and decrease cycle of ultraviolet rays in the depth direction is different according to the wavelength λa and the wavelength λb. Therefore, the depth position when the intensity of ultraviolet rays takes each peak value is different according to the wavelength λa and the wavelength λb, and the depth position when the intensity of ultraviolet rays takes each bottom value B1 to B4 (minimum value) is also different according to the wavelength λa and the wavelength λb. For example, near the depth position of 140nm, the intensity of ultraviolet rays with wavelength λa takes the bottom value B3, while the intensity of ultraviolet rays with wavelength λb takes the peak value. That is, the area near the depth position of 140nm can make up for the insufficient intensity of ultraviolet rays with wavelength λa by the intensity of ultraviolet rays with wavelength λb.

[0160] That is, the plurality of ultraviolet irradiators 2a and 2b irradiate the main surface of the substrate W1 with ultraviolet rays, thereby generating the dissociation reaction of formula (1) by ultraviolet rays of wavelength λb even in the region where the intensity of ultraviolet rays of wavelength λa is low. Thus, ozone can be generated even in this region. Therefore, ozone can be generated in a wider region in the gap between patterns P1.

[0161] In addition, according to the substrate processing device 10C, the intensity of ultraviolet light becomes higher in a wider area in the gap between the patterns P1. Therefore, the organic matter between the patterns P1 can be removed in a wider area by the decomposition function of the organic matter caused by the ultraviolet light itself. However, since the photon energy of the ultraviolet light with a long wavelength λb is smaller than the photon energy of the ultraviolet light with a short wavelength λa, the ultraviolet light with a wavelength λb can only cut fewer types of molecular bonds compared to the ultraviolet light with a wavelength λa. That is, even in an area where the intensity of the ultraviolet light with a wavelength λb increases, as long as the intensity of the ultraviolet light with a wavelength λa is low, the decomposition of the organic matter caused by the decomposition function of the ultraviolet light itself will not be sufficient.

[0162] In the substrate processing device 10C, the oxygen concentration in the processing space H1 is adjusted to a predetermined concentration range in the same manner as the substrate processing device 10. Therefore, the function of removing organic matter using ozone can be effectively used. That is, since the ultraviolet light of wavelength λb can also produce a dissociation reaction in the same manner as the ultraviolet light of wavelength λa, even in the area where the intensity of the ultraviolet light of wavelength λa is low in the gap between the patterns P1, ozone can be generated in the area as long as the intensity of the ultraviolet light of wavelength λb is high. Therefore, the ozone can decompose and remove the organic matter in the area. Thus, the organic matter in the area can be appropriately removed.

[0163] As described above, according to the substrate processing apparatus 10C, the amount of ozone generated in the gaps between the patterns P1 can be increased, and organic substances between the patterns P1 can be appropriately removed.

[0164] Next, an example of a method for selecting a peak wavelength is described. The wavelengths λa and λb are selected so that the intensity of the ultraviolet light with a wavelength λb reaches a peak in at least one region of the regions R1 to R4 where the intensity of the ultraviolet light with a wavelength λa is low. Thus, the ultraviolet light with a wavelength λb can make up for the insufficient intensity of the ultraviolet light with a wavelength λa in the region.

[0165] Next, an example of the definition of regions R1 to R4 is described in more detail. Here, region Rn (n is 1 to 4) is defined by the center of region Rn in the depth direction and the width of region Rn in the depth direction. Specifically, the center of region Rn is equal to the depth position when the intensity of ultraviolet light of wavelength λa takes the valley value Bn (n is 1 to 4), and the width of region Rn is equal to the half-period of the increase and decrease cycle of the intensity of ultraviolet light of wavelength λa. That is, region Rn is the following region: the depth position when the intensity of ultraviolet light takes the valley value Bn is taken as the center, and the half-period of the increase and decrease cycle is taken as the width.

[0166] In such region Rn, the intensity of ultraviolet light with wavelength λa is low. Therefore, as long as the intensity of ultraviolet light with wavelength λb reaches a peak at any point in region Rn, ultraviolet light with wavelength λb can effectively compensate for the insufficient intensity of ultraviolet light with wavelength λa in the region.

[0167] In addition, if Fig.11 As shown in FIG. 1 , the valley value Bn tends to decrease as the depth increases. Therefore, in the region R3 or the region R4 located at a deeper position, the insufficient intensity of the ultraviolet light with a wavelength λa becomes more significant. Therefore, it is expected that the intensity of the ultraviolet light with a wavelength λb in the region R3 or the region R4 reaches a peak. Fig.11 In the example of FIG. 1 , the intensity of the ultraviolet light with a wavelength of λb reaches a peak in the region R3 . Thus, the significant intensity deficiency of the ultraviolet light with a wavelength of λa in the region R3 can be compensated by the ultraviolet light with a wavelength of λb.

[0168] To explain in a more general way, as long as the middle point in the height direction of the pattern P1 (at Fig.11 The wavelength λb may be selected so that the intensity of ultraviolet rays having the wavelength λb reaches a peak in any region within the regions R3 and R4 located on the lower end side of the pattern P1 (the depth position is 100 nm in the figure).

[0169] In the above example, although two types of ultraviolet irradiators 2a and 2b are provided, three or more types of ultraviolet irradiators 2 having different peak wavelengths may be provided. Thus, since the ultraviolet rays in the gaps between the patterns P1 compensate for each other's insufficient intensity in a wider area, a large amount of ozone can be generated in a wider area.

[0170] Although the substrate processing apparatus has been shown and described in detail, the above description is illustrative and not restrictive in all aspects. Therefore, the embodiments of the substrate processing apparatus may be appropriately modified or omitted within the scope of the disclosure. In addition, the above embodiments may be appropriately combined.

[0171] Description of Reference Numerals

[0172] 1: Substrate holding part

[0173] 2,2a,2b: UV irradiator

[0174] 4: Gas supply unit

[0175] 7: Control Department

[0176] 10, 10A to 10C: Substrate processing device

[0177] W1: substrate

[0178] P1: Microstructure (pattern).

Claims

1. A substrate processing device, characterized in that: have: a substrate holding portion that holds a substrate; an ultraviolet irradiator, which is opposed to the surface of the substrate across a processing space and is arranged parallel to the surface of the substrate; a gas supply unit for supplying gas to the processing space; a control unit configured to control the gas supply unit to supply the gas so that the oxygen concentration in the processing space is within a concentration range of 0.3 vol% to 8.0 vol%, and to irradiate the entire surface of the substrate with ultraviolet rays from the ultraviolet irradiator; and an oxygen concentration sensor disposed on a downstream side of the flow of the gas relative to the processing space and avoiding a space directly above the substrate, The gas supply unit supplies an inert gas and oxygen as the gas to the processing space. The control unit controls the flow rate of the gas based on the concentration value detected by the oxygen concentration sensor so that the oxygen concentration in the processing space falls within the concentration range.

2. The substrate processing device according to claim 1, characterized in that: The control unit increases the flow rate of the inert gas and decreases the flow rate of oxygen to decrease the oxygen concentration, and decreases the flow rate of the inert gas and increases the flow rate of oxygen to increase the oxygen concentration, thereby adjusting the oxygen concentration to the concentration range.

3. The substrate processing device according to claim 1 or 2, characterized in that: The plurality of ultraviolet irradiators irradiate the surface of the substrate with ultraviolet rays having different peak wavelengths, respectively.

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