TWI745860B - Substrate processing method and substrate processing apparatus - Google Patents

Abstract

Provided is a substrate processing method that can remove organic matter even in the gaps between fine structures formed on the surface of the substrate. The substrate processing method includes a substrate holding step and an ultraviolet irradiation step. In the substrate holding step, the substrate with the fine structure formed on the surface is held. In the ultraviolet irradiation step, an ultraviolet irradiator facing the surface of the substrate through the processing space irradiates the surface of the substrate with ultraviolet rays. During at least a part of the ultraviolet irradiation step, 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 to 8.0 vol% or less.

Description

Substrate processing method and substrate processing device

The invention relates to a substrate processing method and a substrate processing device.

Conventionally, in the manufacturing process of a semiconductor substrate (hereinafter simply referred to as a "substrate"), a substrate processing apparatus is used to perform various processing on the substrate. For example, a chemical solution is supplied to a substrate with 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 rinse process of a chemical solution for supplying pure water to the substrate to rinse the surface and a drying process of pure water for removing the surface are performed.

In the case where multiple fine patterns (hereinafter also referred to as microstructures) are formed on the surface of the substrate, when the cleaning and drying treatments are carried out in sequence, the surface tension of pure water will act on the microstructures during the drying process. This leads to the possibility of collapse of the fine structure. Such a collapse is that the width of the fine structure is narrow and the higher the aspect ratio, the easier it is.

In order to suppress such collapse, a water-repellent treatment has been proposed, in which the surface of the fine structure is water-repellent (hydrophobicized) to form a water-repellent film (organic film). In the water repellent treatment, most of the silylating agents are used as the water repellent, and in order to improve the water repellent effect of the silylating agent, a treatment for mixing the active agent with the silylating agent is also performed.

On the other hand, after the drying treatment, the water-repellent film becomes unnecessary. Therefore, a method for removing organic matter has also 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 (UV) is used as an organic matter removal device. The main surface of the substrate on which the organic substance is formed is irradiated with ultraviolet rays, whereby the ultraviolet rays act on the organic substance to decompose and remove the organic substance. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] JP 2011-204944 A. [Patent Document 2] JP 2018-166183 A.

[The problem to be solved by the invention]

From the viewpoint of decomposition of organic matter, it is preferable to use ultraviolet rays with high photon energy, that is, to use ultraviolet rays with a short wavelength. The reason for this is that the higher the energy of the photon, the more types of molecular bonds can be cut, which can quickly decompose organic matter.

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. In this way, when the gap between the microstructures becomes narrower, the shorter the wavelength of ultraviolet light becomes, the more difficult it is for the gap between the microstructures to enter. The reason for this is that ultraviolet rays with short wavelengths are difficult to diffract. In this way, in the case where it is difficult for ultraviolet rays to enter the gaps of the microstructures, it is difficult for the ultraviolet rays to act on the organic substances existing in the gaps of the microstructures. Therefore, the removal of organic matter becomes insufficient.

Therefore, an object of the present invention is to provide a substrate processing method and a substrate processing apparatus that can remove organic substances even in the gaps between the fine structures formed on the surface of the substrate. [Means to solve the problem]

The substrate processing method of the first aspect includes: a substrate holding step for holding a substrate with a fine structure formed on the surface; and an ultraviolet irradiation step for opposing an ultraviolet irradiator facing the surface of the substrate through a processing space The surface of the substrate is irradiated with ultraviolet rays; during at least part of the ultraviolet irradiation step, 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 to 8.0 vol% or less .

The substrate processing method of the second aspect is the substrate processing method described in the first aspect, wherein the oxygen concentration in the processing space is adjusted to 0.6 vol% or more to 7.0 during at least a part of the ultraviolet irradiation step. Within the concentration range below vol%.

The substrate processing method of the third aspect is the substrate processing method described in the first aspect or the second aspect, in which an inert gas and oxygen are supplied as the aforementioned gas to the aforementioned processing space.

The substrate processing method of the fourth aspect is the substrate processing method described in any one of the first aspect to the third aspect, wherein the flow rate of the gas is controlled so that the flow rate of the gas is measured downstream of the gas flow. The concentration value detected by the oxygen concentration sensor for the foregoing processing space becomes within the foregoing concentration range.

The substrate processing method of the fifth aspect is the substrate processing method described in any one of the first aspect to the fourth aspect, wherein in the ultraviolet irradiation step, the substrate is processed from a plurality of ultraviolet irradiators. The aforementioned surface is irradiated with ultraviolet rays having different peak wavelengths.

The substrate processing method of the sixth aspect is the substrate processing method described in any one of the first aspect to the fifth aspect, wherein the fine structure includes a pattern with a pattern width of 50 nm or less and an aspect ratio of 3.5 or more .

The substrate processing apparatus of the first aspect includes: a substrate holding portion that holds the substrate; an ultraviolet irradiator that faces the surface of the substrate through the processing space; a gas supply portion that supplies gas to the processing space; and control The part is controlled so that the gas supply part supplies the gas so that the oxygen concentration in the processing space becomes a concentration range of 0.3 vol% or more to 8.0 vol% or less, while the ultraviolet irradiator is applied to the surface of the substrate. Expose ultraviolet rays.

The substrate processing apparatus of the second aspect is the substrate processing apparatus described in the first aspect, wherein the gas supply unit supplies an inert gas and oxygen as the gas to the processing space.

The substrate processing apparatus of the third aspect is the substrate processing apparatus described in the first aspect or the second aspect, and further includes: an oxygen concentration sensor, which is provided downstream of the flow of the gas with respect to the processing space Side; The control unit controls the flow of the gas based on the concentration value detected by the oxygen concentration sensor so that the oxygen concentration in the processing space becomes a concentration range of 0.3 vol% or more to 8.0 vol% or less. [Efficacy of invention]

According to the substrate processing method of the first aspect and the sixth aspect and the substrate processing apparatus of the first aspect, the amount of ozone generated near the surface of the substrate can be increased. Since ozone generated in the vicinity of the surface of the substrate easily enters the gap between the fine structures, the organic matter existing in the gap between the fine structures can be removed.

According to the substrate processing method of the second aspect, the organic matter in the gaps of the fine structures can be removed more appropriately.

According to the substrate processing method of the third aspect and the substrate processing apparatus of the second aspect, the oxygen concentration in the processing space can be rapidly changed. In particular, the oxygen concentration in the processing space can be rapidly increased by supplying oxygen.

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, so that the oxygen concentration in the processing space can be more reliably adjusted to the concentration range .

According to the substrate processing method of the fifth aspect, the intensity of ultraviolet rays can be increased in a wider area among the gaps of the fine structure. Therefore, it is possible to increase the amount of ozone generated in the gaps of the fine structures. Therefore, the organic matter in the gaps of the fine structures can be removed more appropriately.

Hereinafter, the embodiment will be described in detail with reference to the drawings. In order to explain the positional relationship of each configuration, an XYZ orthogonal coordinate system with the Z direction as the vertical direction and the XY plane as the horizontal plane is appropriately attached to the drawing. 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 introduced as appropriate below. "+Z axis side" means the upper side in the Z direction, and "-Z axis side" means the lower side in the Z direction.

[First Embodiment] [Substrate Processing Equipment] 1 and 2 are diagrams schematically showing an example of the structure of the substrate processing apparatus 10. The substrate W1 is carried into the substrate processing apparatus 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 microstructure refers to patterns such as metal patterns, semiconductor patterns, and resist patterns. Therefore, the main surface of the substrate W1 has an uneven shape caused by a fine structure.

The fine structure is formed in a process before the substrate W1 is carried into the substrate processing apparatus 10. For example, by supplying a chemical solution to the substrate W1 on which the resist pattern is formed and performing an etching process, a pattern such as metal is formed on the main surface of the substrate W1. After the etching treatment, cleaning treatment, water repellent treatment, and drying treatment are performed. The cleaning process is a process for supplying pure water to the substrate W1 and rinsing the chemical solution. The drying process is, for example, a process of drying the substrate W1 by rotating the substrate W1 on a horizontal plane. In the middle of drying, the surface tension of pure water will cause the fine structure to collapse. The higher the aspect ratio (ratio of height to width) of such a collapsed microstructure is, the more likely it is. For example, a microstructure with an aspect ratio of 3.5 or more tends to collapse. Here, the maximum aspect ratio of the fine structure formed on the substrate W1 is set to 3.5 or more. In addition, here, the minimum value of the mutual spacing of the fine structures formed on the substrate W1 is, for example, 50 nm or less. Hereinafter, the fine structure is also referred to as a pattern.

In order to suppress this collapse, the water repellent treatment is performed before the drying treatment. The water-repellent treatment is a process in which a treatment liquid containing a water-repellent agent is supplied to the main surface of the substrate W1 to form a water-repellent film (organic substance) on the surface of the pattern. Thereby, the surface tension of 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, such a water-repellent film is not required in semiconductor products. Therefore, it is desirable to remove the water-repellent film after the drying process.

In addition, in processes other than the water-repellent treatment, organic matter may be formed or adhered 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 expected that the organic matter is also removed after the treatment with the organic solvent.

The substrate processing apparatus 10 performs organic matter removal processing on the substrate W1. Therefore, the substrate processing apparatus 10 can be regarded as an organic matter removing apparatus. As shown in FIG. 1, 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.

[Substrate holding part] The substrate holding portion 1 is a member for holding the substrate W1. In the case where the substrate W1 is a semiconductor substrate (that is, a semiconductor wafer), the substrate W1 has a substantially circular flat plate shape. The substrate holding portion 1 holds the substrate W1 in a horizontal posture in which the thickness direction of the substrate W1 is along the Z direction. The substrate W1 holds the main surface on which the pattern is formed toward the Z-axis side.

The substrate holding portion 1 has a substantially disc-shaped base 11, and has an upper surface 1a, a side surface 1b, and a lower surface 1c. The upper surface 1a is the surface facing the substrate W1. In the example of FIG. 1 and FIG. 2, a pair of grooves 111 are formed in the upper surface 1a. The hands of an external substrate transfer robot (not shown) are inserted into the pair of slots 111. That is, when the substrate W1 is transferred between the substrate holding unit 1 and an external substrate transfer robot (not shown), the hands of the substrate transfer robot enter the pair of grooves 111. Thereby, it is possible to prevent the hand of the substrate transfer robot from colliding with the substrate holding portion 1. The side surface 1b connects the peripheral edge of the upper surface 1a and the peripheral edge of the lower surface 1c. A substrate W1 is placed on the upper surface 1 a of the substrate holding portion 1. The base 11 of the substrate holding portion 1 can be formed of ceramics or the like, for example.

The substrate holding portion 1 may also rotate the substrate W1 around a rotation axis Q1 parallel to the Z axis passing through the center portion of the substrate W1. In the example of FIG. 1, the substrate holding portion 1 further includes a rotating mechanism 12. The rotation mechanism 12 includes a motor (not shown) to rotate the base 11 around the rotation axis Q1. Thereby, the substrate W1 held by the base 11 also rotates around the rotation axis Q1.

[Ultraviolet irradiator] The ultraviolet irradiator 2 is installed on the +Z-axis side than the substrate holding portion 1 and faces the substrate W1 across the processing space H1 (refer to FIG. 2). The ultraviolet irradiator 2 irradiates the main surface of the substrate W1 held by the substrate holding portion 1 with ultraviolet rays. As the ultraviolet irradiator 2, for example, light sources such as a low-pressure mercury lamp, a high-pressure mercury lamp, an excimer lamp, a metal halide lamp, and a UV-LED (Light Emitting Diode) are used. In the example of FIGS. 1 and 2, a plurality of ultraviolet irradiators 2 are provided as the ultraviolet irradiators 2. In addition, the ultraviolet irradiator 2 does not necessarily need to be installed in plural, and only one may be installed.

Although the shape of the ultraviolet irradiator 2 is arbitrary, for example, the ultraviolet irradiator 2 may be a point light source. In this case, the plurality of ultraviolet irradiators 2 are dispersed and arranged slightly evenly with respect to the main surface of the substrate W1. Thereby, the ultraviolet irradiator 2 can irradiate ultraviolet rays to the entire surface of the main surface of the substrate W1 more uniformly.

Alternatively, the ultraviolet irradiator 2 may also be a line light source. The ultraviolet irradiator 2 has a rod-like shape that is long in the longitudinal direction. The plurality of ultraviolet irradiators 2 are arranged side by side along the X direction with the longitudinal direction of the ultraviolet irradiators 2 along the Y direction. Alternatively, the ultraviolet irradiator 2 may have a ring shape. The plurality of ultraviolet irradiators 2 are arranged in concentric circles. These ultraviolet irradiators 2 also irradiate ultraviolet rays to the entire main surface of the substrate W1.

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 arranged to be slightly parallel to the main surface of the substrate W1. The ultraviolet irradiator 2 may cover the substrate W1 when viewed in plan (that is, when viewed from the Z-axis side). Thereby, the ultraviolet irradiator 2 can irradiate the entire surface of the substrate W1 with ultraviolet rays.

Quartz glass 21 is provided on the -Z axis side than the ultraviolet irradiator 2 (specifically, between the ultraviolet irradiator 2 and the substrate W1). The quartz glass 21 has heat resistance, corrosion resistance, and transparency to ultraviolet rays. Light plate-like body. The quartz glass 21 is arranged slightly horizontally, and faces 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 apparatus 10. The ultraviolet light from the ultraviolet irradiator 2 is irradiated to the main surface of the substrate W1 through the quartz glass 21.

The ultraviolet irradiator 2 irradiates the main surface of the substrate W1 with ultraviolet rays while the rotating mechanism 12 is rotating the substrate W1. Thereby, the main surface of the substrate W1 can be irradiated with ultraviolet rays more uniformly.

[Lifting mechanism] In the example of FIG. 1 and FIG. 2, the board|substrate holding part 1 (more specifically, the base 11) is provided so that it may be raised and lowered along the Z direction. More specifically, a lifting mechanism 13 is provided in the substrate processing apparatus 10. The elevating mechanism 13 is capable of moving the substrate holding portion 1 in the Z direction. For example, the elevating mechanism 13 is attached to the lower surface 1c of the base 11 via the rotating mechanism 12. The lifting mechanism 13 is capable of reciprocating the substrate holding portion 1 between a first position (refer to FIG. 2) and a second position (refer to FIG. 1). The first position is a position where the substrate holding portion 1 is close to the ultraviolet irradiator 2. The second position is a position where the substrate holding portion 1 is away from the ultraviolet irradiator 2. As described later, the first position is the position of the substrate holding portion 1 when the substrate W1 is processed using ultraviolet rays, and the second position is the position of the substrate holding portion 1 when the substrate W1 is transferred and received. The distance between the substrate holding portion 1 and the ultraviolet irradiator 2 in the first position is shorter than the distance between the substrate holding portion 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 may also be covered by bellows.

[Cylinder member] In the example of FIGS. 1 and 2, the cylindrical member 3 is provided in the substrate processing apparatus 10. The cylindrical 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 3 a of the cylindrical member 3 is larger than the diameter of the side surface 1 b of the substrate holding portion 1. 2, in a state where the substrate holding portion 1 is stopped at the first position, the inner peripheral surface 3 a of the cylindrical member 3 surrounds the side surface 1 b of the substrate holding portion 1.

In a state where the substrate holding portion 1 is stopped at the first position (FIG. 2 ), the ultraviolet irradiator 2 irradiates ultraviolet rays. In this way, the substrate W1 is treated with ultraviolet rays. On the other hand, in a state where the substrate holding portion 1 is stopped at the first position, the periphery of the substrate W1 is surrounded by the quartz glass 21, the cylindrical member 3, and the substrate holding portion 1. Therefore, the substrate W1 cannot be easily taken out from the substrate holding portion 1 in this state.

Therefore, the elevating mechanism 13 moves the substrate holding portion 1 to the second position (FIG. 1 ). Thereby, the substrate holding portion 1 retreats from the inside of the inner peripheral surface 3a of the cylindrical member 3 in a direction away from the ultraviolet irradiator 2. In the second position, the substrate W1 is located on the -Z axis side with respect to the lower surface 3d of the cylindrical member 3. Therefore, the substrate W1 is carried out from the substrate processing apparatus 10 by a substrate transfer robot (not shown) without being hindered by the cylindrical member 3. Conversely, in a state where the substrate holding portion 1 is stopped at the second position, the substrate transfer robot places the substrate W1 on the substrate holding portion 1.

[Removal of organic matter] As described above, the ultraviolet irradiator 2 irradiates ultraviolet rays with the substrate holding portion 1 at the first position. The ultraviolet system is irradiated to the main surface of the substrate W1 held by the substrate holding portion 1. Since the energy of ultraviolet photons is large and the molecular bonds of organic substances can be cut, the organic substances (for example, water-repellent film) formed on the main surface of the substrate W1 can be decomposed and removed.

However, it is difficult for ultraviolet rays to enter the -Z axis side in the gaps between the patterns formed on the main surface of the substrate W1. FIG. 3 shows the simulation results of the intensity division 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 belonging to the main body and a silicon oxide film P12 formed on the surface of the silicon P11. The example in FIG. 3 shows the intensity distribution of ultraviolet rays when the wavelength of the ultraviolet rays is 172 nm, the height and width of the pattern P1, and the interval between the patterns P1 are 200 nm, 20 nm, and 10 nm, respectively. Although FIG. 3 shows the intensity of ultraviolet rays in the vicinity of two patterns P1, the actual simulation is performed on a structure in which three or more patterns P1 are arranged in the horizontal direction at the same interval (pitch).

In Fig. 3, the intensity of ultraviolet rays is shown by contour lines C1 to C6. The contour lines C1 to C6 indicate that the smaller the number at the end of the symbol, the higher the intensity of ultraviolet rays. That is, the contour line C1 represents the ultraviolet light with the highest intensity, and the contour line C6 represents the ultraviolet light with the lowest intensity. In the example of FIG. 3, sandy mesh points are provided in the area divided by contour lines C1 to C6. The higher the intensity of the ultraviolet rays, the denser the dots of the sandy land assigned to each area.

As illustrated in FIG. 3, the intensity of ultraviolet rays has a tendency that even if it becomes stronger or weaker toward the -Z axis side, as a whole, it decreases toward the -Z axis side. The reason why the intensity of ultraviolet rays decreases toward the -Z axis side is that the ultraviolet rays are difficult to refract. In addition, the reason why the intensity of the ultraviolet light is strong or weak is that the ultraviolet light that has entered between the patterns is reflected and interfered with each other.

In a region where the intensity of the ultraviolet rays is high, the ultraviolet rays can effectively act on the organic matter formed on the sidewall of the pattern P1, so that the organic matter can be sufficiently removed. On the other hand, in a region where the intensity of ultraviolet light is small (for example, the area indicated by contour lines C5 and C6), ultraviolet light cannot sufficiently remove the organic matter formed on the sidewall of the pattern P1. Hereinafter, the organic matter formed on the sidewall of the pattern P1 is also referred to as the organic matter between the patterns P1.

Therefore, in this embodiment, the function of decomposing organic substances by ozone is utilized. Ozone is generated by irradiating ultraviolet rays to the air (including oxygen) in the processing space H1. Specifically, when ultraviolet rays (UV) are irradiated to oxygen molecules (O ₂ ) in the processing space H1, oxygen atoms (O) are generated by the dissociation represented by the following formula (1). _{Next, ozone (O 3} ) is generated by a three-body reaction of oxygen atoms (O), oxygen molecules (O ₂ ), and surrounding gas (M) represented by the following formula (2).

Formula (1): O ₂ ＋UV→O＋O Formula (2): O ₂ ＋O＋M→O ₃ ＋M

As long as ozone acts on the organic matter on the main surface of the substrate W1, the organic matter can be decomposed and removed. In order for ozone to effectively act on the organic matter between the patterns P1 of the substrate W1, it is desirable to generate ozone in the vicinity of the main surface of the substrate W1. The reason for this is that since ozone generated near the main surface of the substrate W1 approaches the pattern P1, there is a high possibility of entering between the patterns P1, and it is easy to act on the organic matter between the patterns P1.

In addition, as can be understood from the formula (1), the amount of ozone produced increases as the number of oxygen molecules increases and the intensity of ultraviolet rays increases. Therefore, first consider increasing the number of oxygen molecules in the processing space H1. That is, the oxygen concentration in the processing space H1 is increased. In addition, here, since the width coefficient mm in the Z direction of the processing space H1 is as narrow as mm, the oxygen concentration in the processing space H1 can be regarded as substantially uniform.

On the other hand, the intensity of the ultraviolet rays on the main surface of the substrate W1 decreases as the oxygen concentration in the processing space H1 increases. The reason for this is that ultraviolet rays are absorbed by oxygen molecules through the dissociation reaction of formula (1). That is, when the oxygen concentration in the processing space H1 is increased, most of the ultraviolet rays are absorbed by oxygen molecules before reaching the main surface of the substrate W1. Therefore, the intensity of ultraviolet rays on the main surface of the substrate W1 decreases.

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, and on the other hand, the intensity of ultraviolet rays on the main surface of the substrate W1 decreases. Therefore, the increase in the oxygen concentration in the processing space H1 may conversely reduce the amount of ozone generated near the main surface of the substrate W1.

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

Formula (3): v=k1×(x－x0)×2x

k1 is a constant of proportionality. Since it is considered that the partial pressure x of the oxygen atom is proportional to the illuminance I of ultraviolet rays and the x/x0 system is much less than 1, the formula (3) can be changed to the formula (4).

Formula (4): v=k2×x0×I

According to formula (4), it is considered that the ozone generation rate v is proportional to the product of the oxygen concentration and the illuminance of ultraviolet rays.

The following Table 1 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.

[Table 1] Oxygen concentration [vol%] Illumination of ultraviolet rays [mW／cm ² ] Ozone generation rate 20.1 4.7 1.00 4.4 23.1 1.08

The oxygen concentration and ultraviolet illuminance in Table 1 are the results obtained through experiments. According to Table 1, when the oxygen concentration in the processing space H1 is 20.1 vol%, the illuminance of ultraviolet rays on the main surface of the substrate W1 is 4.7 mW/cm ² . Since it is considered that the oxygen concentration in the processing space H1 is uniform, the oxygen concentration on the main surface of the substrate W1 is also 20.1 vol%. Therefore, at this time, the generation rate of ozone generated on the main surface of the substrate W1 is proportional to the product of the ^{oxygen concentration (20.1 vol%) and the illuminance (4.7 mw/cm 2 ).} In Table 1, the ozone generation rate at this time is normalized to 1 and displayed.

In addition, according to Table 1, when the oxygen concentration is 4.4 vol%, the illuminance of ultraviolet rays on the main surface of the substrate W1 becomes 23.1 mW/cm ² . That is, it can be seen that the illuminance of ultraviolet rays on the main surface of the substrate W1 is increased by reducing the oxygen concentration. Also, at this time, the generation rate of ozone generated on the main surface of the substrate W1 was 1.08. That is, when the oxygen concentration is 4.4 vol%, the amount of ozone generated on the main surface of the substrate W1 is relatively larger than when the oxygen concentration in the processing space H1 is 20.1 vol%.

Therefore, compared with when the oxygen concentration in the processing space H1 is 20.1 vol%, when the oxygen concentration is 4.4 vol%, the decomposition performance of organic substances due to ozone is relatively large.

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

Figure 4 is a graph showing the relationship between the degree of removal of organic matter and the oxygen concentration. In FIG. 4, the contact angle of the liquid when the liquid has been applied to the substrate W1 is used as an index to show the degree of organic matter removal. The contact angle means that the smaller the value of the contact angle, the greater the degree of removal of organic matter. FIG. 4 shows the results of experiments when the substrate processing apparatus 10 irradiates the main surface of the substrate W1 with ultraviolet rays for a predetermined irradiation time.

As illustrated in FIG. 4, it can be seen that the waveform of the contact angle has a downwardly convex shape, and there is an optimal oxygen concentration range. In the example of FIG. 4, the reference line A1 is displayed. The reference line A1 shows the contact angle when the liquid is applied to the substrate W1 on which no organic substance has been formed on the main surface. Therefore, when the contact angle becomes less than or equal to the reference line A1, the organic matter on the substrate W1 can be appropriately removed by the ultraviolet irradiation treatment. According to the graph in Fig. 4, since the oxygen concentration in the processing space H1 becomes 0.3 vol% or more to 8.0 vol% or less, the contact angle becomes below the reference line A1. Therefore, organic matter can be removed appropriately when the oxygen concentration is within this range. .

In addition, the reason why the degree of removal of organic matter is low in the range where the oxygen concentration is higher than 8.0 vol% is considered as follows. That is, the reason is that 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, resulting in a decrease in the intensity of the ultraviolet rays on the main surface of the substrate W1. Insufficiency of ultraviolet rays causes the generation rate of ozone to be generated near the main surface of the substrate W1 to decrease, so that the decomposition performance of organic substances caused by ozone cannot be effectively exerted.

On the other hand, the reason why the degree of removal of organic matter is low in the range where the oxygen concentration is lower than 0.3 vol% is considered as follows. That is, the reason is that when the oxygen concentration is small, the amount of oxygen molecules in the processing space H1 is small, and therefore, 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 pattern P1 is small, and the organic matter is not completely removed and remains.

Therefore, in this embodiment, the oxygen concentration in the processing space H1 is adjusted to a predetermined concentration range (0.3 vol% or more and 8.0 vol% or less) during at least a part of the ultraviolet ray irradiation period.

[Gas Supply Department] 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 be within a predetermined concentration range. Hereinafter, the gas supplied by the gas supply unit 4 is referred to as adjustment gas. As the adjustment gas, for example, an inert gas (for example, nitrogen or argon) can be used.

In the example of FIGS. 1 and 2, the gas supply unit 4 supplies the adjustment gas to the processing space H1 through the through holes 321 and 322 formed in the cylindrical member 3. Hereinafter, first, the through holes 321 and 322 will be described. The through holes 321 and 322 penetrate the cylindrical member 3 and communicate with the space between the quartz glass 21 and the substrate W1. In the example of FIGS. 1 and 2, one ends of the through holes 321 and 322 are opened on the upper surface 3 c of the cylindrical member 3. Hereinafter, one ends of the through holes 321 and 322 are also referred to as openings (air supply openings) 321a and 322a. In the positions where the openings 321a and 322a are formed, the upper surface 3c of the cylindrical member 3 is opposed to the peripheral edge portion of the quartz glass 21 via the gap. The openings 321a and 322a are connected to the processing space H1. That is, the through holes 321 and 322 communicate with the processing space H1. In a plan view, the openings 321a and 322a are formed at positions facing each other via the central axis of the inner peripheral surface 3a.

In the example of FIGS. 1 and 2, 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 321 b 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 322 b 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 system is supplied from the common pipe 411 to the processing space H1 via the branch pipes 412 and 413 and the through holes 321 and 322.

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 that can adjust the flow rate of the adjustment gas toward the processing space H1.

[hermetic space] The substrate processing apparatus 10 may also form a closed space. In the example of FIG. 1 and FIG. 2, the top member 52, the cylindrical member 3, the partition wall 5, and the bottom 51 are connected to each other and form a sealed space. The peripheral edge portion of the lower surface of the top member 52 has a protrusion shape protruding on the +Z axis side (the side of the cylindrical member 3). Conversely, the lower surface of the top member 52 has a concave shape in which the center portion 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 is abutted to the inner surface of the protrusion shape of the top member 52. The portion on the outer peripheral side of the upper surface 3c of the cylindrical member 3 is a protrusion shape connected to the top member 52 in the Z direction. The openings 321a and 322a of the through holes 321 and 322 are formed 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 cylindrical 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 portion 1, and elevating mechanism 13 are housed in a closed space formed by the top member 52, the cylindrical member 3, the partition wall 5, and the bottom 51.

[exhaust] A through hole 53 for exhaust gas is formed in the partition wall 5. The through hole 53 is connected to the exhaust portion 61. The exhaust portion 61 includes a pipe 611 connected to the through hole 53. The gas system inside the substrate processing apparatus 10 is exhausted to the external exhaust unit 61 via the pipe 611.

[Shutter] The partition wall 5 is provided with a shutter (not shown) that functions as an entrance and exit for the substrate W1. When the shutter is opened, the inside of the substrate processing apparatus 10 communicates with the outside. The substrate transfer robot system can carry the substrate W1 into and out of the substrate processing apparatus 10 through the opened shutter.

[Control Department] The control unit 7 systematically 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 transfer robot.

The control unit 7 may also be an electronic circuit, and has, for example, a data processing device and a storage medium. The data processing device may also be an arithmetic processing device such as a CPU (Central Processor Unit; central processing unit). The memory unit may also have a non-transitory storage medium (such as ROM (Read Only Memory) or a hard disk) and a temporary storage medium (such as RAM (Random Access Memory)). It is also possible to store, for example, a program for specifying the processing to be executed by the control unit 7 in a non-transitory storage medium. The processing device executes the program, whereby the control unit 7 can execute the processing prescribed by the program. Of course, part or all of the processing executed by the control unit 7 may be executed by hardware.

The control unit 7 controls the gas supply unit 4 to supply the adjustment gas so that the oxygen concentration in the processing space H1 becomes a concentration range of 0.3 vol% or more to 8.0 vol% or less, while causing the ultraviolet irradiator 2 to face the substrate W1. The main surface is irradiated with ultraviolet rays. Hereinafter, an example of the operation of the substrate processing apparatus 10 will be described in detail.

[Operation of substrate processing equipment] FIG. 5 is a flowchart showing an example of the operation of the substrate processing apparatus 10. The elevating mechanism 13 initially stops the substrate holding portion 1 at the second position (FIG. 1 ). In addition, as an example here, the exhaust system of the exhaust portion 61 is constantly performed. In step S1 (substrate holding process), the control unit 7 opens the shutter and controls the substrate transport robot to arrange the substrate W1 on the substrate holder 1, and then close the shutter. A microstructure is formed on the main surface on the +Z axis side of the substrate W1, and an organic substance (for example, a water-repellent film) is present on the surface of the microstructure. The substrate holding portion 1 holds the substrate W1.

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. Thereby, the adjustment gas is respectively ejected from the openings 321 a and 322 a, and at least a part of the air in the processing space H1 is pushed out by the adjustment gas to the outside of the processing space H1 and exhausted toward the exhaust portion 61. Specifically, the air in the processing space H1 flows toward the -Z axis side in the space between the inner peripheral surface 3 a of the cylindrical member 3 and the side surface 1 b of the base 11, and is exhausted from the through hole 53 toward the exhaust portion 61. Thereby, at least a part 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 part of the air in the processing space H1 is replaced with the adjustment gas, the oxygen concentration in the processing space H1 decreases. In addition, the execution order of steps S1 and S2 can also be reversed, and steps S1 and S2 can also be executed in parallel.

Next, in step S3, the control unit 7 controls the elevating mechanism 13 so that the substrate holding unit 1 (base 11) approaches the ultraviolet irradiator 2 and stops 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 executed after step S2, as long as it is executed after step S1.

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 in the state where the susceptor 11 is stopped at the first position becomes within a predetermined concentration range. The flow rate of the adjustment gas may also be preset, for example, by simulation or experiment.

Next, in step S4, the control unit 7 controls the rotation mechanism 12 to rotate the substrate W1. Specifically, the control unit 7 rotates the substrate holding unit 1 (base 11). Thereby, the substrate W1 is rotated in the horizontal plane. In addition, step S4 does not necessarily need to be executed after step S3, as long as it is executed after step S1.

Next, in step S5, the control unit 7 determines whether the replacement of the atmosphere in the processing space H1 has ended. 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 by whether the elapsed time from step S3 is longer than the first predetermined time set in advance. The timing of the elapsed time can be performed by a timing circuit such as a time measuring circuit. The first time is the time required for the oxygen concentration to become within a predetermined concentration range, which can be preset by simulation or experiment. The control unit 7 determines that the oxygen concentration in the processing space H1 has become a predetermined concentration range when the elapsed time from step S3 is longer than the first predetermined time.

When the control unit 7 has determined 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 has determined 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.

The ultraviolet irradiator 2 irradiates ultraviolet rays, and the substrate W1 is subjected to a removal process of organic matter using ultraviolet rays. Specifically, the first step: ultraviolet rays act on the organic matter (for example, a water-repellent film) existing on the main surface of the substrate W1, thereby decomposing and removing the organic matter. The second step: ultraviolet rays are absorbed by the 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.

As described above, since the oxygen concentration in the processing space H1 is adjusted to be within a predetermined concentration range, a lot of ozone is generated in the vicinity of the main surface of the substrate W1. This ozone system easily acts on the organic matter between the patterns P1, so that the organic matter between the patterns P1 can also be decomposed and removed.

Next, in step S7, the control unit 7 determines whether or not the processing for the substrate W1 should be ended. 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 has been determined that the processing should not be terminated, the control unit 7 executes step S7 again. On the other hand, when it has been determined that the processing should be terminated, the control unit 7 causes the ultraviolet irradiator 2 to stop irradiating ultraviolet rays in step S8. This completes the removal process of organic matter using ultraviolet rays. The ultraviolet irradiation period is the period from step S6 to step S8, and the process from step S6 to step S8 corresponds to the ultraviolet irradiation step.

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, respectively. Next, the control unit 7 controls the elevating mechanism 13 to lower the substrate holding unit 1 to the second position and open the shutter. The substrate transfer robot transports the substrate W1 from which the organic matter has been removed from the substrate holding unit 1.

As described above, according to the substrate processing apparatus 10, during the ultraviolet irradiation period, the oxygen concentration in the processing space H1 is maintained within a predetermined concentration range (0.3 vol% or more and 8.0 vol% or less). Therefore, the organic matter between the patterns P1 on the main surface of the substrate W1 can also be appropriately 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 that 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 appropriately removed.

In addition, in the above example, the irradiation of ultraviolet rays is started while the oxygen concentration in the processing space H1 is maintained within a predetermined concentration range (steps S5 and S6). That is, the oxygen concentration is adjusted to be within a predetermined concentration range in the entire period of the ultraviolet irradiation period. However, it is not limited to this. For example, it is also possible to bring the oxygen concentration to a predetermined concentration range after starting to irradiate ultraviolet rays. In short, it is sufficient that the control unit 7 adjusts the oxygen concentration within a predetermined concentration range during at least a part of the ultraviolet irradiation period. The reason for this is that the organic matter in the gaps between the patterns P1 can be removed during at least a part of the ultraviolet irradiation period.

[Range of oxygen concentration] As shown in FIG. 4, the waveform of the contact angle becomes convex downward, and the contact angle becomes substantially constant (minimum value) in the range of the oxygen concentration from 0.6 vol% or more to 7.0 vol% or less. Therefore, a range of 0.6 vol% or more and 7.0 vol% or less can also be adopted as the predetermined concentration range. Thereby, the organic matter on the main surface of the substrate W1 can be removed more appropriately.

[Second Embodiment] FIG. 6 is a diagram schematically showing an example of the configuration of the substrate processing apparatus 10A. FIG. 6 shows the structure of the substrate processing apparatus 10A in a state where the substrate holding portion 1 has stopped at the first position. The substrate processing apparatus 10A has the same configuration as the substrate processing apparatus 10 except for the presence of the oxygen-free concentration sensor 9.

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. In the example of FIG. 6, the oxygen concentration sensor 9 is installed avoiding the space directly above the substrate W1 held by the substrate holding portion 1. If the oxygen concentration sensor 9 is installed in the space directly above the substrate W1, the ultraviolet ray from the ultraviolet irradiator 2 will irradiate the oxygen concentration sensor 9 to prevent the ultraviolet ray from irradiating the main surface of the substrate W1. In contrast, in the substrate processing apparatus 10A, since the oxygen concentration sensor 9 is provided avoiding the space directly above the substrate W1, the ultraviolet rays from the ultraviolet irradiator 2 can be appropriately irradiated to the main surface of the substrate W1.

The oxygen concentration sensor 9 may be provided on the downstream side of the flow of the adjustment gas with respect to the processing space H1. In the example of FIG. 6, the oxygen concentration sensor 9 is provided at a position opposed to the inner peripheral surface 3 a of the cylindrical member 3. More specifically, the oxygen concentration sensor 9 is located between the inner peripheral surface 3 a of the cylindrical member 3 and the side surface 1 b of the base 11 in a state where the base 11 of the substrate holding portion 1 is at the first position.

The gas system in the processing space H1 flows through the flow path between the inner peripheral surface 3 a of the cylindrical member 3 and the side surface 1 b of the base 11 and is discharged from the exhaust portion 61. Since it can be considered that the oxygen concentration of the gas flowing in the flow path between the inner peripheral surface 3a of the cylindrical member 3 and the side surface 1b of the base 11 is approximately equal to the oxygen concentration in the processing space H1, the oxygen concentration sensor 9 is The oxygen concentration in the processing space H1 can be detected.

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 falls within a predetermined concentration range. The control unit 7 executes oxygen concentration control during at least a part of the period during which the ultraviolet irradiator 2 irradiates ultraviolet rays.

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

For example, the control unit 7 controls the supply valve 42 to reduce the flow rate of the adjustment gas when the oxygen concentration value is lower than the target value. When the flow rate of the adjustment gas flowing into the processing space H1 decreases, the air in the non-processing space H2 (see FIG. 6) below the cylindrical member 3 is partially introduced into the processing space H1. Since the oxygen concentration in the non-processing space H2 is higher than the oxygen concentration in the processing space H1, the oxygen concentration in the processing space H1 increases. That is, the oxygen concentration in the processing space H1 can be brought close to the target value.

On the other hand, the control unit 7 can control the supply valve 42 and 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 adjustment gas, the oxygen concentration in the processing space H1 decreases. Therefore, the oxygen concentration in the processing space H1 can be brought close to the target value.

As described above, according to the substrate processing apparatus 10A, since the control unit 7 controls the adjustment gas so that the oxygen concentration value detected by the oxygen concentration sensor 9 falls within a predetermined concentration range, the processing space H1 can be more reliably maintained. The oxygen concentration inside is adjusted to a predetermined concentration range.

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

FIG. 8 is a diagram schematically showing an example of the configuration of the substrate processing apparatus 10B. FIG. 8 shows the structure of the substrate processing apparatus 10B in a state where the substrate holding portion 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.

The gas supply unit 4 illustrated in FIG. 8 supplies an inert gas and oxygen as adjustment gases 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.

One end of the branch pipe 414 is connected to 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.

By opening both the supply valves 42 and 44, the mixed gas of the inert gas and oxygen is ejected into the processing space H1 from the openings 321a and 322a as the adjustment gas. The control unit 7 controls the supply valves 42 and 44 to adjust the flow rate of the inert gas and the flow rate of oxygen, whereby the oxygen concentration of the adjustment gas can be adjusted.

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 (that is, the flow rates of 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 executes oxygen concentration control during at least a part of the period during which the ultraviolet irradiator 2 irradiates ultraviolet rays.

An example of the operation of the substrate processing apparatus 10A is the same as the flowchart of FIG. 5. However, the control unit 7 executes the above-mentioned oxygen concentration control during the execution of steps S6 to S8. For example, the control unit 7 controls the supply valves 42 and 44 when reducing the oxygen concentration in the processing space H1 to reduce the oxygen concentration of the adjustment gas. As a specific example, the control unit 7 controls the supply valves 42 and 44 to decrease the flow rate of oxygen while increasing the flow rate of the inert gas. For example, the control unit 7 may control the flow rate of oxygen to zero. Thereby, the oxygen concentration in the processing space H1 can be rapidly reduced.

On the other hand, the control unit 7 controls the supply valves 42 and 44 to increase the oxygen concentration of the adjustment gas when increasing 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 oxygen while decreasing the flow rate of the inert gas. Thereby, the oxygen concentration in the processing space H1 can be rapidly increased.

As described above, according to the substrate processing apparatus 10B, the gas supply unit 4 also supplies oxygen. Thereby, by adjusting the oxygen concentration of the adjustment gas as described above, it is possible to increase the rate of change of the oxygen concentration in the processing space H1. Therefore, processing throughput can be improved.

[Third Embodiment] As already explained with reference to FIG. 3, the intensity of the ultraviolet rays is present in the depth direction of the pattern P1. Therefore, in the gaps between the patterns P1, ozone is likely to be generated in a region where the intensity of ultraviolet rays is high, and it is difficult to generate ozone in a region where the intensity of ultraviolet rays is low. Therefore, in the third embodiment, ozone is generated in a wider area of the gap between the patterns P1.

FIG. 9 is a diagram schematically showing an example of the configuration of the 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.

A plurality of ultraviolet irradiators 2 are provided in the substrate processing apparatus 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 frequency spectrum" is explained. Different spectrum means that the peak wavelengths contained in the spectrum of the light output from the light source are different from each other. The so-called peak wavelength refers to the wavelength at which the intensity of light in the spectrum takes the peak. There are multiple peak wavelengths in the spectrum of a light source. For example, the peak wavelengths of ultraviolet rays irradiated from a low-pressure mercury lamp are plural, such as 185 nm to 254 nm. Hereinafter, the peak wavelength is also abbreviated as wavelength.

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 spectrum of light irradiated from these various light sources is different from each other.

In addition, even for the same kind of light source, the frequency spectrum may be different. For example, the excimer lamp is equipped with a quartz tube filled with a discharge gas (for example, a diluent gas or a diluent gas halogen compound) and a pair of electrodes. The discharge gas system exists between a pair of electrodes. A high frequency and a high voltage are applied between the pair of electrodes, whereby the discharge gas is excited and becomes an excimer state. The discharge gas system generates ultraviolet rays when returning from the excimer state to the substrate state. The spectrum of the ultraviolet ray irradiated from the excimer lamp will vary depending on the type of discharge gas, etc. Specifically, the peak wavelength of the ultraviolet ray irradiated from the excimer lamp is 126 nm, 146 nm, 172 nm, 222 nm, or 308 nm depending on the type of discharge gas.

That is, as the plurality of ultraviolet irradiators 2, multiple types of light sources such as low-pressure mercury lamps and excimer lamps may be used, or the same type of light sources with different frequency spectra may be used.

An example of the operation of the substrate processing apparatus 10C is the same as the flowchart of FIG. 5. However, in step S6, the control unit 7 irradiates both of the ultraviolet irradiators 2a and 2b with ultraviolet rays.

Since the peak wavelength of the first ultraviolet light irradiated by the ultraviolet irradiator 2a is different from the peak wavelength of the second ultraviolet light irradiated by the ultraviolet irradiator 2b, the period of the intensity of the first ultraviolet light in the gap between the patterns P1 It is different from the period of the intensity of the second ultraviolet rays in the gaps between the patterns P1.

10 and 11 are diagrams showing an example of the intensity of ultraviolet rays in the vicinity of the pattern P1 of the substrate W1 for each wavelength. Figure 10 and Figure 11 show the simulation results. The left side of the paper in FIG. 10 shows the results when ultraviolet rays of the wavelength λa (=126 nm) are used, and the right side of the paper in FIG. 10 shows the results when ultraviolet rays of the wavelength λb (=172 nm) are used. In the example of FIG. 10, the intensity of ultraviolet rays is shown by contour lines C1 to C4. The intensity of the ultraviolet ray shown by the contour lines C1 to C4 is higher as the number of the symbol is smaller. That is, the intensity shown by the contour C1 is the highest, the intensity shown by the contour C4 is the lowest, and the intensity shown by the contour C2 is higher than the intensity shown by the contour C3.

In the examples of FIGS. 10 and 11, the height and width of the pattern P1 are set to 200 nm and 10 nm, respectively. Although the intensity of ultraviolet rays in the vicinity of one pattern P1 is shown in FIG. 10, the actual simulation was performed for a structure in which a plurality of patterns P1 are arranged at the same interval (pitch) in the horizontal direction. In the simulation, the pitch of the pattern P1 was set to 50 nm. Therefore, the width of the gap between the patterns P1 is 40 nm.

In FIG. 11, the intensity of ultraviolet rays on the side surface of the pattern P1 is shown for the depth direction (Z direction) of the gap between the patterns P1. Hereinafter, the position in the depth direction of the gap between the patterns P1 is referred to as a depth position. In addition, the depth position of the upper end (the end on the +Z axis side) of the pattern P1 is defined as 0 nm. Since the height of the pattern P1 is 200 nm, the depth position of the lower end (the end on the -Z axis side) of the pattern P1 becomes 200 nm. In FIG. 11, the intensity of the ultraviolet light of the wavelength λa from the ultraviolet irradiator 2a is shown by a solid line, and the intensity of the ultraviolet light of the wavelength λb from the ultraviolet irradiator 2b is shown by a broken line.

As shown in Figures 10 and 11, the intensity of the ultraviolet light of the wavelength λa shows the following tendency: as the depth position goes from the upper end to the lower end of the pattern P1, even if the intensity of the ultraviolet light of the wavelength λa repeatedly increases and decreases, the peak value (maximum value) remains Slowly lower. On the other hand, although the intensity of the ultraviolet rays of the wavelength λb repeatedly increases and decreases as the depth position goes from the upper end to the lower end of the pattern P1, the peak value hardly decreases. The reason for this is that since the wavelength λb is longer than the wavelength λa, the ultraviolet ray of the wavelength λb is easier to enter the gap between the patterns P1 than the ultraviolet ray of the wavelength λa.

The period of increase and decrease of ultraviolet rays in the depth direction is due to the difference between the wavelength λa and the wavelength λb. Therefore, the depth position when the intensity of the ultraviolet light takes each peak is different from the wavelength λa and the wavelength λb, and when the intensity of the ultraviolet light takes each bottom value B1 to B4 (minimum value), the depth position is also at the wavelength λa and the wavelength. λb is different. For example, in the vicinity of the depth position of 140 nm, the intensity of the ultraviolet rays of the wavelength λa takes the bottom value B3, and the intensity of the ultraviolet rays of the wavelength λb takes the peak value. That is, in the region near the depth position of 140 nm, the intensity of the ultraviolet light of the wavelength λb can make up for the insufficient intensity of the ultraviolet light of the wavelength λa.

That is, both of the plurality of ultraviolet irradiators 2a and 2b irradiate the main surface of the substrate W1 with ultraviolet rays, thereby being able to generate the formula (1) by the ultraviolet rays of the wavelength λb even in the region where the intensity of the ultraviolet rays of the wavelength λa is low Dissociation reaction. Thereby, ozone can be generated even in a region where the intensity of ultraviolet rays of the wavelength λa is low. Therefore, ozone can be generated in a wider area among the gaps between the patterns P1.

In addition, according to the substrate processing apparatus 10C, the intensity of ultraviolet rays becomes higher in a wider area among the gaps 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 rays. However, since the photon energy of the ultraviolet light with the long wavelength λb is smaller than that of the ultraviolet light with the short wavelength λa, the ultraviolet light with the wavelength λb can only cut fewer kinds of molecular bonds than the ultraviolet light with the wavelength λa. . That is, even in a region where the intensity of the ultraviolet light of the wavelength λb increases, as long as the intensity of the ultraviolet light of the wavelength λa is low, the decomposition of the organic matter due to the decomposition function of the ultraviolet itself will not be sufficient.

In the substrate processing apparatus 10C, the oxygen concentration in the processing space H1 is also adjusted to be within a predetermined concentration range similarly to the substrate processing apparatus 10. Therefore, the removal function of organic matter that has already used ozone can be effectively utilized. That is, since ultraviolet rays of wavelength λb can also generate dissociation reactions like ultraviolet rays of wavelength λa, even in the region where the intensity of ultraviolet rays of wavelength λa in the gap between patterns P1 is low, as long as the intensity of ultraviolet rays of wavelength λb is high Then, ozone can be generated even in the region where the intensity of the ultraviolet light of the wavelength λa in the gap between the patterns P1 is low. Therefore, ozone can decompose and remove the organic matter in the region where the intensity of the ultraviolet light of the wavelength λa in the gap between the patterns P1 is low. Thereby, the organic matter in the region where the intensity of the ultraviolet light of the wavelength λa in the gap between the patterns P1 is low can be appropriately removed.

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 the organic matter between the patterns P1 can be appropriately removed.

Next, an example of the consideration method for selecting the peak wavelength will be described. The wavelengths λa and λb are selected so that the intensity of the ultraviolet rays of the wavelength λb takes the peak value in at least one of the regions R1 to R4 where the intensity of the ultraviolet rays of the wavelength λa is small. Thereby, the ultraviolet rays of the wavelength λb can make up for the insufficient intensity of the ultraviolet rays of the wavelength λa in this region.

Next, an example of the definition of the regions R1 to R4 will be described in more detail. Here, the region Rn is defined by the center of the region Rn in the depth direction and the width of the region Rn in the depth direction (n is 1 to 4). Specifically, the center of the region Rn is equal to the depth position when the intensity of the ultraviolet light of the wavelength λa takes the bottom value Bn (n is 1 to 4), and the width of the region Rn is equal to the period of increase and decrease of the intensity of the ultraviolet light of the wavelength λa The half cycles are equal. That is, the region Rn is a region in which the depth position when the intensity of the ultraviolet rays takes the bottom value Bn is taken as the center, and the half period of the increase/decrease cycle is taken as the width.

In such a region Rn, the intensity of ultraviolet rays having the wavelength λa is low. Therefore, in any place in the region Rn, as long as the intensity of the ultraviolet rays of the wavelength λb takes a peak, the ultraviolet rays of the wavelength λb can effectively make up for the insufficient intensity of the ultraviolet rays of the wavelength λa in the region.

In addition, as shown in FIG. 11, the bottom value Bn shows a tendency that the deeper the depth position, the smaller it becomes. Therefore, in the region R3 or the region R4 located at a deeper position, the insufficient intensity of the ultraviolet rays of the wavelength λa becomes more significant. Therefore, it is desirable that the intensity of the ultraviolet rays of the wavelength λb in the region R3 or the region R4 take a peak. In the example of FIG. 11, the intensity of the ultraviolet rays of the wavelength λb takes a peak in the region R3. This makes it possible to compensate for the significant lack of intensity of the ultraviolet rays of the wavelength λa in the region R3 by the ultraviolet rays of the wavelength λb.

To explain in a more general way, as long as the wavelength is greater than the midpoint in the height direction of the pattern P1 (the depth position is 100 nm in FIG. 11) and is located at any of the regions R3 and R4 on the lower end side of the pattern P1. The wavelength λb can be selected so that the intensity of the ultraviolet rays of λb takes the peak value.

In addition, 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 from each other may be provided. Thereby, since ultraviolet rays compensate for each other's insufficient intensity in a wider area in the gap between the patterns P1, a lot of ozone can be generated in a wider area.

Although the substrate processing apparatus has been shown and described in detail, the above description is illustrative rather than restrictive in all aspects. Therefore, the embodiment of the substrate processing apparatus may be appropriately changed or omitted within the scope disclosed in the specification. In addition, the above-mentioned embodiments can be combined as appropriate.

1: Board holding part 1a, 3c: upper surface 1b: side 1c, 3d: bottom surface 2, 2a, 2b: UV irradiator 3: Tube member 3a: inner peripheral surface 3b: outer peripheral surface 4: Gas supply part 5: Next door 7: Control Department 9: Oxygen concentration sensor 10, 10A to 10C: Substrate processing equipment 11: Pedestal 12: Rotating mechanism 13: Lifting mechanism 21: Quartz glass 41,611: Piping 42,44: supply valve 43: gas supply source 45: Oxygen supply source 51: bottom 52: Top member 53,321,322: Through hole 61: Exhaust 111: Groove 321b, 322b: the other end 321a, 322a: opening 411: Common Pipe 412,413,414: branch pipe A1: Baseline B1 to B4: bottom value C1 to C6: contour lines H1: Processing space H2: Non-processing space P1: Pattern P11: Silicon P12: Silicon oxide film Q1: Rotation axis R1 to R4: area W1: substrate λa, λb: wavelength

[Fig. 1] A diagram schematically showing an example of the configuration of a substrate processing apparatus. [Fig. 2] A diagram schematically showing an example of the structure of a substrate processing apparatus. [Fig. 3] A diagram schematically showing an example of the intensity distribution of ultraviolet rays. [Figure 4] is a graph showing the relationship between contact angle and oxygen concentration. [FIG. 5] A flowchart showing an example of the operation of the substrate processing apparatus. Fig. 6 is a diagram schematically showing another example of the structure of the substrate processing apparatus. [Fig. 7] A diagram schematically showing an example of the electrical configuration of the substrate processing apparatus. [Fig. 8] A diagram schematically showing another example of the configuration of the substrate processing apparatus. Fig. 9 is a diagram schematically showing another example of the configuration of the substrate processing apparatus. Fig. 10 is a diagram schematically showing an example of the intensity distribution of ultraviolet rays. [Fig. 11] A graph schematically showing an example of the intensity of ultraviolet rays.

Claims (5)

A substrate processing method comprising: a substrate holding step of holding a substrate with a fine structure formed on the surface, the fine structure including a pattern with a pattern width of 50 nm or less and an aspect ratio of 3.5 or more; and an ultraviolet irradiation step, An ultraviolet irradiator arranged opposite to the surface of the substrate and parallel to the surface of the substrate in the processing space irradiates the entire surface of the substrate with ultraviolet rays; during at least a part of the ultraviolet irradiation step, The processing space is supplied with gas and the oxygen concentration in the processing space is adjusted to a concentration range of 0.6 vol% or more and 7.0 vol% or less, which is the minimum value of the contact angle of the substrate. The substrate processing method according to claim 1, wherein an inert gas and oxygen are supplied to the processing space as the gas. The substrate processing method according to claim 1 or 2, 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 for the processing space becomes the aforementioned Within the concentration range. The substrate processing method according to claim 1 or 2, wherein in the ultraviolet irradiation step, the surface of the substrate is irradiated with ultraviolet rays having different peak wavelengths from a plurality of ultraviolet irradiators, respectively. A substrate processing apparatus is provided with: a substrate holding portion for holding a substrate; an ultraviolet irradiator arranged to face the surface of the substrate and parallel to the surface of the substrate through a processing space; The gas supply unit supplies gas to the processing space; the control unit controls such that the gas supply unit supplies the gas so that the oxygen concentration in the processing space becomes a concentration range of 0.3 vol% or more to 8.0 vol% or less , While allowing the ultraviolet irradiator to irradiate the entire surface of the substrate with ultraviolet rays; and the oxygen concentration sensor is arranged on the downstream side of the flow of the gas, avoiding the space directly above the substrate with respect to the processing space; The gas supply unit supplies 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 to make the oxygen concentration in the processing space It becomes the aforementioned concentration range.

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