JP7660344B2 - Gas Supply Equipment - Google Patents

Description

The present invention relates to a gas supply device, and more specifically, to a gas supply device for processing an object by spraying gas onto the object after it has been irradiated with ultraviolet light.

A technique has been known in the past to remove organic compounds adhering to the surface of an object by irradiating the gas with vacuum ultraviolet light to activate the gas, and then spraying the activated gas onto the surface of the object (see, for example, Patent Document 1).

JP 2007-98357 A

However, through intensive research by the present inventors, it has been found that the structure described in Patent Document 1 does not allow gas containing a high concentration of radicals to be sprayed onto an object. The present inventors speculate that the reason for this is that in the structure described in Patent Document 1, the light source for irradiating the gas with ultraviolet light to generate radicals is too far away from the location of the object onto which the gas containing radicals is sprayed, causing many of the radicals to be deactivated before the gas reaches the object.

In view of the above problems, the present invention aims to provide a gas supply device that can spray a gas containing radicals at a higher concentration than conventional gas supply devices onto an object.

The gas supply device according to the present invention comprises:
a gas inlet into which a source gas containing a source material serving as a radical source is introduced;
a gas flow passage through which the raw material gas flows after being introduced from the gas inlet;
a light source that emits ultraviolet light toward a light irradiation region in the gas flow passage;
a gas outlet through which a treated gas, which is the raw material gas after being irradiated with the ultraviolet light, is discharged to the outside;
The gas supply system further comprises a first heating section for increasing the temperature of the source gas at a position closer to the gas inlet than the light irradiation region.

In this specification, the term "radical" refers to a general term for chemical species (atoms, molecules) that have an unpaired electron. Examples of these include O( ^3P ), hydroxyl radical (.OH), hydrogen radical (.H), _.NH2 , .NH, etc. Among these, when O( ^3P ) is planned as the radical, the source material is a material that contains oxygen atoms, and the source gas can be, for example, a mixed gas containing oxygen or air.

Radicals are highly reactive and have an extremely short lifespan. More specifically, radicals disappear within a short period of time as they bond with other atoms or molecules in the gas surrounding them. For this reason, the configuration of Patent Document 1 makes it difficult to irradiate a target object with a gas that contains a high concentration of radicals.

For example, when the raw material serving as the radical source is a material containing oxygen atoms, the oxygen radical O( ^3P ) is easily converted into ozone ( _O3 ) by combining with oxygen molecules through the reaction of the following formula (1).
O( ³ P) + O ₂ → O ₃ (1)

The gas supply device according to the present invention is provided with a first heating section that raises the temperature of the raw material gas at a position upstream of the light irradiation area in the gas flow direction. That is, the raw material gas in a heated state is supplied to the light irradiation area and irradiated with ultraviolet light. Once generated, the radicals are less likely to undergo bonding reactions with other atoms or molecules the higher the temperature.

In addition, ozone ( _O3 ) has a property of absorbing ultraviolet light slightly more easily than oxygen (O2). According to the above configuration, the amount of ozone ( _O3 ) generated is suppressed, which makes it easier for ultraviolet light to reach the inside of the gas flow passage, thereby increasing the efficiency of generating radicals.

In other words, according to the above configuration, the temperature of the raw material gas is raised and then irradiated with ultraviolet light, so that the radicals once generated are less likely to be deactivated. This makes it possible to discharge the processed gas containing a higher concentration of radicals than in the past to the outside.

Furthermore, some raw materials serving as radical sources release radicals again when the products generated by the radicals bonding with atoms or molecules are decomposed. For example, when the raw material contains oxygen atoms, oxygen radicals O( ^3P ) may be generated again from ozone ( _O3 ) generated by the above formula (1) according to the following formula (2):
O ₃ → O ( ³ P) + O ₂ (2)

The reaction of formula (2) is the reverse reaction of formula (1) and is likely to occur when the temperature of the gas containing ozone ( _O3 ) is high. Therefore, according to the above configuration, depending on the raw material that serves as the radical source, the probability of regenerating radicals that have once bonded and disappeared increases, and the radical concentration can be further increased.

The gas flow passage may be covered with a heat retaining material at least at a position between the first heating section and the light irradiation area.

With the above configuration, the raw material gas can be led to the light irradiation region while maintaining its temperature at a high level. This allows the radical concentration in the processed gas to be further improved.

The gas supply device may be equipped with multiple gas inlets through which multiple source gases with different gas temperatures are introduced.

The gas supply device may include a second heating section that heats the raw gas or the processed gas flowing through the light irradiation area.

According to the above configuration, the raw gas or the processed gas flows through the light irradiation area while maintaining a high temperature, and is led to the gas outlet side. This makes it possible to further increase the concentration of radicals contained in the processed gas.

The ultraviolet light emitted from the light source may have a light intensity in a region where the wavelength is less than 230 nm. More preferably, the ultraviolet light emitted from the light source may have a main emission wavelength of less than 230 nm.

In this specification, the term "main emission wavelength" refers to the emission wavelength with the highest light intensity, or the wavelength λi in the wavelength range Z(λi) that shows an integrated intensity of 40% or more of the total integrated intensity in the emission spectrum when a wavelength range Z(λ) of ±10 nm from a certain wavelength λ is defined on the emission spectrum. For example, in a light source that has an extremely narrow half-width and shows light intensity only at a specific wavelength, such as an excimer lamp filled with a specific luminous gas, the wavelength with the highest relative intensity (main peak wavelength) can usually be taken as the main emission wavelength.

The light source may be, for example, an excimer lamp that uses a gas containing at least one material belonging to the group consisting of Xe, Ar, Kr, ArBr, ArF, KrCl, and KrBr as the luminous gas. For example, an excimer lamp that contains Xe as the luminous gas has a main emission wavelength of ultraviolet light of 172 nm.

With this configuration, by placing the object to be treated at a position 10 mm away from the gas outlet, the treated gas containing a high concentration of radicals can be sprayed onto the object to be treated.

The gas supply device of the present invention allows gas (processed gas) containing radicals at a higher concentration than in the past to flow out of the gas outlet, and makes it possible to spray such gas against an object.

FIG. 2 is a cross-sectional view illustrating a configuration example of a gas supply device. 2 is a schematic cross-sectional view of the gas supply device shown in FIG. 1 taken in a direction different from that in FIG. 1 . 2 is another schematic cross-sectional view of the gas supply device shown in FIG. 1 cut in a direction different from that in FIG. 1 . 1 is a graph showing an emission spectrum of an excimer lamp filled with a light emitting gas containing Xe and an absorption spectrum of oxygen (O ₂ ) superimposed on each other. FIG. 11 is a cross-sectional view illustrating another configuration example of a gas supply device. FIG. 11 is a cross-sectional view illustrating another configuration example of a gas supply device. FIG. 11 is a cross-sectional view illustrating another configuration example of a gas supply device. FIG. 11 is a cross-sectional view illustrating another configuration example of a gas supply device. FIG. 11 is a cross-sectional view illustrating another configuration example of a gas supply device. FIG. 11 is a cross-sectional view illustrating another configuration example of a gas supply device. FIG. 11 is a cross-sectional view illustrating another configuration example of a gas supply device. 12 is a cross-sectional view showing a schematic configuration example of a light source included in the gas supply device shown in FIG. 11. 12 is a cross-sectional view showing a schematic configuration example of a light source included in the gas supply device shown in FIG. 11. FIG. 11 is a cross-sectional view illustrating another configuration example of a gas supply device. FIG. 11 is a cross-sectional view illustrating another configuration example of a gas supply device. FIG. 11 is a cross-sectional view illustrating another configuration example of a gas supply device. FIG. 2 is a cross-sectional view showing a model structure of a gas supply device used in a simulation. 13 is a graph showing a simulation result.

Embodiments of the gas supply device according to the present invention are described below. Note that the following figures are merely schematic illustrations, and the dimensional ratios in the drawings do not necessarily match the actual dimensional ratios. Furthermore, the dimensional ratios may not match between the drawings.

"structure"
FIG. 1 is a cross-sectional view showing a schematic configuration example of a gas supply device according to the present embodiment. The gas supply device 1 shown in FIG. 1 includes a cylindrical housing 3, a light source 5 arranged in the housing 3, a gas inlet 11 through which a raw material gas G1 to be processed flows, a gas flow passage 10 through which the raw material gas G1 flows, and a heating unit 51 (corresponding to a "first heating unit"). The gas supply device 1 also includes a gas outlet 12 connected to the gas flow passage 10 and at an end opposite to the gas inlet 11 (an end on the side of an object 40 to be described later). The heating unit 51 will be described later.

The gas supply device 1 irradiates the raw material gas G1 flowing through the gas flow passage 10 with ultraviolet light L1 emitted from the light source 5, causing a photochemical reaction in the raw material material that serves as a radical source contained in the raw material gas G1, and generates a processed gas G2 containing radicals, which is discharged (supplied) to the outside. In other words, the gas supply device 1 is a device for generating and supplying the processed gas G2 containing radicals. In addition, in this specification, the "processed gas G2" refers to the raw material gas G1 after the ultraviolet irradiation process has been performed.

More specifically, a light irradiation region 5b is formed in the gas flow passage 10, where ultraviolet light L1 emitted from the light source 5 is irradiated. When the raw material gas G1 passes through this light irradiation region 5b, a processed gas G2 containing radicals is generated from the raw material gas G1.

Figure 1 also shows an object 40 placed in a position opposite the gas outlet 12. Surface treatment of the object 40 is performed by spraying post-treatment gas G2 containing radicals onto the surface (object surface) 40a of the object 40.

The source gas G1 is a gas containing a source material that serves as a radical source. For example, when O( ^3P ) is planned as the radical, the source material is a material containing oxygen atoms, and the source gas may be, for example, a mixed gas containing oxygen or air. The type of source gas G1 introduced into the gas supply device 1 may be appropriately selected depending on the radical to be generated.

The light source 5 has a light-emitting surface 5a that emits ultraviolet light L1 toward the gas flow passage 10. This light-emitting surface 5a is formed along the shape of the gas flow passage 10, in other words, along the flow direction of the raw material gas G1 (or the processed gas G2).

In the gas supply device 1 shown in FIG. 1, the light source 5 has a shape extending in the direction d1 from the gas inlet 11 toward the gas outlet 12 as the longitudinal direction. In this embodiment, an excimer lamp is used as an example of the light source 5. An example of the structure in this case will be described with reference to FIG. 2. FIG. 2 is a schematic cross-sectional view of the location where the light source 5 of the gas supply device 1 shown in FIG. 1 is located, cut along a plane formed by the directions d2 and d3. Note that FIG. 1 is a schematic cross-sectional view of the gas supply device 1 when cut along a plane formed by the directions d1 and d3.

As shown in FIG. 2, the light source 5 disposed inside the housing 3 has an arc tube 21 extending along the direction d1. More specifically, the arc tube 21 has an outer tube 21a that has a cylindrical shape and is located on the outside, and an inner tube 21b that has a cylindrical shape and a smaller inner diameter than the outer tube 21a and is disposed coaxially inside the outer tube 21a. Both arc tubes 21 (21a, 21b) are made of a dielectric material such as synthetic quartz glass.

A hollow cylindrical space is formed through the inner tube 21b along the tube axis, and this cylindrical space forms the gas flow path 10.

The outer tube 21a and the inner tube 21b are both sealed at their ends in the direction d1 (not shown), and a light-emitting space that has a circular shape when viewed from the direction d1 is formed between the two. A light-emitting gas 23G that forms excimer molecules by discharge is enclosed in this light-emitting space.

The wavelength of the ultraviolet light L1 emitted from the light emitting tube 21 is determined by the material of the light emitting gas 23G. In other words, the material of the light emitting gas 23G is appropriately selected depending on the wavelength desired as the ultraviolet light L1. The light emitting gas 23G can be, for example, a gas containing at least one material belonging to the group consisting of Xe, Ar, Kr, ArBr, ArF, KrCl, and KrBr. When the light emitting gas 23G is realized by using these materials, the main emission wavelength of the ultraviolet light L1 is less than 230 nm.

The light source 5 illustrated in FIG. 2 has a first electrode 31 disposed on the outer wall surface of the outer tube 21a and a second electrode 32 disposed on the inner wall surface of the inner tube 21b. As an example, the first electrode 31 has a film shape, and the second electrode 32 has a mesh shape or a line shape. The first electrode 31 may also have a mesh shape or a line shape like the second electrode 32. These electrodes (31, 32) are connected to a power supply line (not shown).

When a high-frequency AC voltage of, for example, 50 kHz to 5 MHz is applied between the first electrode 31 and the second electrode 32 of the light source 5, which is composed of an excimer lamp, via a power supply (not shown), the voltage is applied to the light-emitting gas 23G via the light-emitting tube 21. At this time, a discharge plasma is generated in the discharge space in which the light-emitting gas 23G is sealed, and the atoms of the light-emitting gas 23G are excited to an excimer state, and excimer emission occurs when these atoms transition to the ground state. When the above-mentioned gas containing xenon (Xe) is used as the light-emitting gas 23G, the excimer emission becomes ultraviolet light L1 with a peak wavelength near 172 nm.

As described above, the second electrode 32 having a mesh or line shape is formed on the inner tube 21b of the arc tube 21. Therefore, a gap exists in the second electrode 32, and the ultraviolet light L1 is irradiated through this gap toward the hollow cylindrical space formed inside the arc tube 21, that is, the light irradiation area 5b in the gas flow passage 10.

As shown in FIG. 3, the first electrode 31 may be formed in a mesh or line shape, and a reflective member 33 that reflects the ultraviolet light L1 may be provided between the first electrode 31 and the housing 3. This reflective member 33 is made of a material that exhibits high reflectivity (e.g., 80% or more) for the ultraviolet light L1, and may be, for example, Al, Al alloy, stainless steel, silica, or silica alumina. If the housing 3 itself is made of a material that exhibits reflectivity for the ultraviolet light L1 (e.g., stainless steel such as SUS), the surface of the housing 3 may be used as the reflective member 33.

Note that, although Figures 2 and 3 show a case where the shape of the arc tube 21 when cut along the plane formed by the directions d2 and d3 is circular, it may be rectangular or of another shape.

4 is a graph showing the emission spectrum of the light source 5 composed of an excimer lamp filled with a light emitting gas 23G containing Xe, superimposed on the absorption spectrum of oxygen ( _O2 ). In Fig. 4, the horizontal axis shows the wavelength, the left vertical axis shows the relative value of the light intensity of the excimer lamp, and the right vertical axis shows the absorption coefficient of oxygen ( _O2 ).

When a gas containing Xe is used as the light emitting gas 23G of the excimer lamp, as shown in FIG. 4, the ultraviolet light L1 emitted from the light source 5 has a main emission wavelength of 172 nm and a band within the range of approximately 160 nm to 190 nm.

When a gas containing oxygen ( _O2 ) is used as the source gas G1, the ultraviolet light L1 of wavelength λ emitted from the light source 5 is irradiated and absorbed by the oxygen ( _O2 ), and the reactions of the following formulas (3) and (4) proceed. In formula (3), O( ^1D ) is an excited O atom, which exhibits extremely high reactivity, and O( ^3P ) is an O atom in the ground state. The reactions of formulas (3) and (4) occur depending on the wavelength component of the ultraviolet light L1.
O ₂ + hν(λ) → O( ¹ D) + O( ³ P) ‥‥(3)
O ₂ + hν(λ) → O( ³ P) + O( ³ P) ‥‥(4)

That is, when the raw material gas G1 is irradiated with the ultraviolet light L1, a processed gas G2 containing radicals such as O( ^1D ) and O( ^3P ) is generated. Since the light emitting surface 5a of the light source 5 extends along the direction d1, the ultraviolet light L1 continues to be irradiated even while the processed gas G2 is flowing through the gas flow passage 10. Therefore, photochemical reactions occur one after another in the raw material material that is the unreacted radical source contained in the processed gas G2. As a result, the processed gas G2 is flowed toward the gas outlet 12 while still containing a high concentration of radicals.

In the above, the radicals to be contained in the processed gas G2 are oxygen radicals such as O( ^3P ), and the raw material is oxygen ( _O2 ). However, if it is desired to generate a processed gas G2 containing other radicals, the material of the raw material gas G1 and the wavelength of the ultraviolet light L1 are selected according to the radical source to be contained.

The gas supply device 1 shown in FIG. 1 includes a heating section 51 on the gas inlet 11 side of the light irradiation area 5b, i.e., upstream of the light irradiation area 5b. The heating section 51 can be a known heating means, such as a halogen lamp, a ceramic heater, or an electric heating wire.

The heating section 51 heats the raw material gas G1 that flows in from the gas inlet 11. As a result, the raw material gas G1 is guided to the light irradiation region 5b in an elevated temperature state. That is, the raw material gas G1 is irradiated with ultraviolet light L1 at a high temperature. As an example, the raw material gas G1 is heated to a temperature of about 100°C or higher and 300°C or lower.

Radicals are highly reactive and have an extremely short lifespan. More specifically, radicals bond with other atoms or molecules in the gas surrounding them, causing the radicals to disappear within a short period of time. For example, O( ³ P) generated in reactions such as those shown in formulas (3) and (4) above is likely to disappear easily according to formula (1) described above in the section "Means for solving the problems." Formula (1) is shown again below.
O( ³ P) + O ₂ → O ₃ (1)

However, the radical bonding reaction defined by the above formula (1) etc. proceeds more slowly at higher temperatures. Therefore, according to the gas supply device 1 of this embodiment, the rate at which radicals generated while the raw material gas G1 passes through the light irradiation region 5b bond with surrounding atoms and molecules and disappear can be slowed down, so that the processed gas G2 containing a high concentration of radicals can be discharged from the gas outlet 12.

In addition, depending on the raw material that serves as the radical source, there are some that produce products by combining radicals with atoms or molecules, and then decompose again to release radicals. For example, ozone ( _O3 ) produced by the above formula (1) may produce oxygen radicals O( ^3P ) again according to formula (2) described above in the section "Means for solving the problems." Formula (2) is shown again below.
O ₃ → O ( ³ P) + O ₂ (2)

This formula (2) corresponds to the reverse reaction of formula (1) above. In other words, the higher the temperature, the more likely this reaction is to proceed. In other words, even if a radical is once generated and disappears by bonding with surrounding atoms or molecules, the probability of it re-radicalizing can be increased. As a result, depending on the raw material that serves as the radical source, the effect of further increasing the concentration of radicals contained in the processed gas G2 can be obtained.

As a secondary effect, the heated post-processing gas G2 is sprayed onto the target surface 40a, which is the surface of the object 40 to be processed, and the temperature of the target surface 40a can be increased. Since the reaction rate of radicals on the target surface 40a increases as the temperature increases, a secondary effect can be expected in that the high temperature of the post-processing gas G2 accelerates the reaction rate on the target surface 40a.

The above will be described later with reference to examples.

<<Variation>>
Various modifications are possible to the structure of the gas supply device 1. Examples of these configurations will be described below.

〈1〉The gas supply devices 1 shown in Figures 5 to 9 have different methods for heating the source gas G1 compared to the gas supply device 1 shown in Figure 1, but are otherwise common.

The gas supply device 1 shown in FIG. 5 includes a pipe 52 connected to the housing 3, and a heating unit 51 is provided to cover part of the outer periphery of the pipe 52. Preferably, a heat-insulating member 53 having a heat-insulating function is disposed around the wall of the pipe 52. This allows the pipe 52 to have a heat-insulating function. The material of the heat-insulating member 53 can be, for example, a material with high heat-insulating properties, such as rock wool or glass wool.

In order to ensure the heat retention of the piping 52, the piping 52 may have a double-pipe structure, and a member with low thermal conductivity such as an air layer or a vacuum layer may be interposed between the inside of the piping 52 (the area through which the raw material gas G1 flows) and the outside of the piping 52. In this case, an air layer or a vacuum layer as a heat retention member 53 is disposed around the inner pipe of the piping 52, which is the area through which the raw material gas G1 flows.

In the case of the gas supply device 1 shown in FIG. 5, the raw material gas G1 flows in from the gas inlet 11, which is an opening at one end of the pipe 52. The internal space of the pipe 52 and the internal space of the housing 3 form a gas flow path 10. While passing through the pipe 52, the raw material gas G1 is heated and heated by the heating unit 51 and is guided to the light irradiation area 5b in the housing 3. By arranging a heat-retaining member 53 around the wall of the pipe 52, the rate at which the temperature of the heated raw material gas G1 drops before it reaches the light irradiation area 5b is suppressed.

In addition, a heating unit 51 may be provided inside the piping 52, as in the gas supply device 1 shown in FIG. 6.

As shown in FIG. 7, when the heating unit 51 is a light source that emits heating light L2, the raw material gas G1 flowing through the pipe 52 may be heated by irradiating light L2 from the heating unit 51 arranged outside the pipe 52. In this case, the raw material gas G1 may be indirectly heated by heating the pipe 52 itself. Also, as shown in FIG. 8, the raw material gas G1 flowing upstream of the light irradiation region 5b in the housing 3 may be heated by irradiating light L2 from the heating unit 51 arranged outside the housing 3.

In the embodiment shown in FIG. 5 and FIG. 6, if the length of the housing 3 in the d1 direction upstream of the light irradiation area 5b is long, the heating unit 51 may be disposed inside or outside the housing 3.

As shown in FIG. 9, raw gases (G1a, G1b) may be introduced from multiple systems via piping 52. Here, raw gas G1b is a gas with a higher temperature than raw gas G1a. The gas supply device 1 shown in FIG. 9 includes a gas inlet 11a through which raw gas G1a is introduced and a gas inlet 11b through which raw gas G1b is introduced, and a heating section 51 is formed by a gas mixing region in piping 52 where raw gas G1a is mixed with raw gas G1b.

<2> In each of the above-described embodiments, the gas flow passage 10 may have a flow region (narrow section) at the end on the gas outlet 12 side where the flow passage cross-sectional area is smaller than that at a position closer to the gas inlet 11 (i.e., the upstream side). For example, the gas supply device 1 shown in FIG. 10 has a narrow section 13 at the end on the gas outlet 12 side where the flow passage cross-sectional area is continuously reduced.

As described above, the raw gas G1 flowing through the gas flow passage 10 is irradiated with ultraviolet light L1 from the light source 5 to become a processed gas G2 containing radicals. When the processed gas G2 reaches the narrow portion 13, the flow rate of the processed gas G2 increases as it flows through the narrow portion 13, proceeds toward the gas outlet 12, and is then discharged from the gas outlet 12 toward the target object 40.

As described above with reference to formula (3), oxygen radicals (O( ^3P )) react with oxygen gas ( _O2 ) in the vicinity to generate ozone (O3). When this reaction occurs ^{, the concentration of O(3P} ₎ decreases.

However, with the above configuration, the flow rate of the processed gas G2 is increased when it is discharged from the gas outlet 12, so that the processed gas G2 can reach the surface of the target object 40 (target surface 40a) within the time in which the reaction of the above formula (3) does not proceed sufficiently. As a result, the processed gas G2 containing a high concentration of radicals can be sprayed onto the target surface 40a.

The configuration of the gas supply device 1, which includes the narrow section 13 on the gas outlet 12 side, can also be appropriately applied to the following modified examples.

<3> In each of the above embodiments, the gas flow passage 10 is formed in the area surrounded by the light-emitting surface 5a. However, the gas flow passage 10 may be formed between the light-emitting surface 5a and the housing 3. For example, in the gas supply device 1 shown in FIG. 11, the light source 5 arranged in the housing 3 is arranged so that its light-emitting surface 5a is surrounded by the wall surface of the housing 3. That is, the raw material gas G1 flows through the gas flow passage 10 formed outside the light source 5, and the light irradiation area 5b is formed outside the light source 5. In this case, the first electrode 31 is formed in a mesh shape or a line shape so as not to hinder the ultraviolet light L1 from being emitted to the outside of the light-emitting tube 21.

In the gas supply device 1 in which the light irradiation area 5b is formed outside the light source 5, the light source 5 is not limited to an excimer lamp having a so-called "double tube structure" as exemplified in Figures 2 and 3.

For example, FIG. 12 is a schematic cross-sectional view of an excimer lamp having a so-called "single-tube structure" as the light source 5, cut along a plane defined by directions d2 and d3. Unlike the light source 5 shown in FIG. 2 and FIG. 3, the light source 5 shown in FIG. 12 has one arc tube 21. The arc tube 21 is sealed (not shown) at the end in the longitudinal direction, i.e., in direction d1, and a light-emitting gas 23G is enclosed in the inner space. A second electrode 32 is disposed inside (inside) the arc tube 21, and a mesh-shaped or linear first electrode 31 is disposed on the outer wall surface of the arc tube 21.

As another example, FIG. 13 is a cross-sectional view, diagrammatically following FIG. 12, of a case where an excimer lamp having a so-called "flat tube structure" is used as the light source 5. The light source 5 shown in FIG. 13 has one arc tube 21 having a rectangular shape when viewed in the longitudinal direction, i.e., in the direction d1. A first electrode 31 is disposed on one outer surface of the arc tube 21, and a second electrode 32 is disposed on the outer surface of the arc tube 21 at a position opposite the first electrode 31. Of the first electrode 31 and the second electrode 32, at least the electrode located on the gas flow passage 10 side has a mesh shape (mesh shape) or a linear shape so as not to impede the emission of ultraviolet light L1 to the outside of the arc tube 21.

In addition, in the light source 5 shown in Figures 12 and 13, the shape when cut in a plane formed by the directions d2 and d3 is not limited to a circle or a rectangle, and various shapes can be adopted.

〈4〉 The gas supply device 1 may include multiple light sources 5. For example, the gas supply device 1 shown in FIG. 14 includes four light sources 5 having light-emitting surfaces 5a extending along the direction d1, and a light irradiation area 5b is formed in the area sandwiched between the light sources 5. In addition, a heating unit 51 is provided inside the housing 3, upstream of the light irradiation area 5b. The other elements are the same as those in the above-mentioned embodiment, and therefore will not be described.

The gas supply device 1 shown in FIG. 1 may be realized by forming a light irradiation area 5b in an area sandwiched between multiple light sources 5. The same applies to other embodiments.

〈5〉 In each of the above embodiments, the light source 5 provided in the gas supply device 1 has been described as having a light-emitting surface 5a that extends in the direction d1 from the gas inlet 11 toward the gas outlet 12 as the longitudinal direction. However, the present invention is not limited to such a structure.

For example, the light source 5 of the gas supply device 1 shown in FIG. 15 has a shape extending in the direction d2 as a longitudinal direction. The gas inlet 11 is configured as an opening extending in the direction d2 on the surface of the housing 3 opposite the target 40. The raw material gas G1 flowing in from the gas inlet 11, which is opened and extended in the direction d2, travels in the directions d1 and d3, is irradiated with ultraviolet light L1, and then is discharged from the gas outlet 12. The gas outlet 12 is configured as an opening extending in the direction d2 on the surface of the housing 3 facing the target 40. As in each of the above embodiments, the gas supply device 1 is provided with a heating unit 51 at a position upstream of the light irradiation area 5b where the ultraviolet light L1 is irradiated from the light source 5.

Even with this configuration, the raw material gas G1 is introduced to the light irradiation region 5b at a high temperature, so that the processed gas G2 containing a high concentration of radicals can flow out from the gas outlet 12.

In addition, in each of the above-mentioned embodiments, the light source 5 can be shaped to extend in the direction d2 as the longitudinal direction, and the gas inlet 11 and the gas outlet 12 can each be configured as an opening extending in the direction d2.

<6> In each of the above-described embodiments, a heating section (corresponding to a "second heating section") that heats the raw gas G1 or the treated gas G2 flowing through the light irradiation region 5b may be provided in addition to the heating section 51. For example, the gas supply device 1 shown in FIG. 16 has a heating section 55 made of a fuel rod or the like installed in a region of the gas flow passage 10 that corresponds to the location where the light irradiation region 5b is formed. This allows the temperature of the treated gas G2 immediately before it flows out of the gas outlet 12 to be further increased, allowing the treated gas G2 to contain a high concentration of radicals.

〈7〉 The configurations of each of the above-mentioned embodiments may be combined to realize the gas supply device 1.

"verification"
The fact that the gas supply device 1 causes the treated gas G2 discharged from the gas outlet 12 to contain a high concentration of radicals was verified by simulation.

Figure 17 is a cross-sectional view showing a model of the gas supply device used in the simulation. The gas supply device model 100 had a light source 5 having a light-emitting surface 5a with a side shape of a cylinder with a length h1 of 50 mm in the direction d1, and a gas flow path 10 in the area surrounded by this light-emitting surface 5a. The gas flow path 10 had a circular gas inlet 11 with a diameter of 5 mm and a circular gas outlet 12 with a diameter of 5 mm. The light source 5 was a Xe excimer lamp with a main peak wavelength of 172 nm.

The target object 40 had a circular shape with a radius r1 of 20 mm, and was placed so that its center was located on the central axis of the gas flow passage 10. The raw material gas G1 was a mixture of 99.5% nitrogen gas and 0.5% oxygen gas, and the humidity was 0%. The raw material gas G1 was introduced into the gas supply device model 100 from the gas inlet 11 at a flow rate of 30 L/min.

In Examples 1 to 3, the temperature of the raw material gas G1 introduced into the gas inlet 11 was set to 100°C, 150°C, and 200°C, respectively. In Comparative Example 1, the temperature of the raw material gas G1 introduced into the gas inlet 11 was set to room temperature (27°C). In the gas supply device model 100 shown in FIG. 17, the light emitting surface 5a, i.e., the light irradiation area 5b, is located immediately adjacent to the gas inlet 11 in the direction d1. Therefore, in order to simulate a state in which the raw material gas G1 is at a high temperature when it is introduced into the light irradiation area 5b, a case in which a high-temperature raw material gas G1 is introduced into the gas inlet 11 in advance was set as Examples 1 to 3, respectively.

In other words, the high-temperature raw material gas G1 assumed in Examples 1 to 3 corresponds to the raw material gas G1 immediately before passing through the heating section 51 and being introduced into the light irradiation region 5b in the gas supply device 1 described above with reference to FIG. 1.

With an illuminance of 50 mW/ ^cm2 on the light-emitting surface 5a, the light irradiation region 5b in the gas flow passage 10 was irradiated with ultraviolet light L1 from the light source 5, while the source gas G1 set to each temperature (100°C, 150°C, 200°C, 27°C) was made to flow in at the above-mentioned flow rate from the gas inlet 11. Then, in both Example 1 and Comparative Example 1, the average concentration of oxygen radicals O( ^3P ) contained in the gas injected into a region within a radius of 2.5 mm (φ5 mm) from the center on the surface of the target object 40 placed at a distance v1 of 10 mm from the gas outlet 12 in the direction d1 was calculated.

The calculation results are shown in Fig. 18. As shown in Fig. 18, in any of the cases of Examples 1 to 3, it was confirmed that the average concentration of oxygen radicals O( ^3P ) contained in the processed gas G2 sprayed onto the surface of the target object 40 increased by more than three times as much as in Comparative Example 1. In particular, it was confirmed that, in Examples 2 and 3 in which the temperature was set to 150°C or higher, the average concentration of oxygen radicals O( ^3P ) contained in the processed gas G2 could be increased by more than four times as much as in Comparative Example 1. This shows that the concentration of radicals contained in the processed gas G2 can be increased by increasing the temperature of the raw material gas G1 at a position upstream of the light irradiation region 5b.

1: Gas supply device 3: Housing 5: Light source 5a: Light emitting surface 5b: Light irradiation area 10: Gas flow passage 11: Gas inlet 11a: Gas inlet 11b: Gas inlet 12: Gas outlet 13: Narrowed portion 21: Arc tube 21a: Outer tube 21b: Inner tube 23G: Light emitting gas 31: First electrode 32: Second electrode 33: Reflecting member 40: Target object 40a: Target surface 51: Heating section (first heating section)
52: Pipe 53: Heat retaining member 55: Heating section (second heating section)
100: Gas supply device model G1: Raw material gas G1a: Raw material gas G1b: Raw material gas G2: Processed gas L1: Ultraviolet light

Claims (7)

a gas inlet into which a source gas containing a source material serving as a radical source is introduced;
a gas flow passage through which the raw material gas flows after being introduced from the gas inlet;
a light source that emits ultraviolet light toward a light irradiation region in the gas flow passage ;
a first heating unit configured to increase a temperature of the source gas at a position closer to the gas inlet than the light irradiation region ;
a gas outlet for discharging a treated gas, which is the raw material gas that has been heated by the first heating section and irradiated with the ultraviolet light, to the outside of the gas flow passage ;
2. A gas supply device comprising: a gas outlet arranged to face an object to be treated when the post-treatment gas is sprayed onto the object to be treated . The gas supply device according to claim 1, characterized in that the gas flow passage is covered with a heat retaining material at least at a position between the first heating section and the light irradiation area. The gas supply device according to claim 1 or 2, characterized in that it is provided with a plurality of gas inlets through which a plurality of the raw material gases having different gas temperatures are introduced. The gas supply device according to any one of claims 1 to 3, characterized in that it is provided with a second heating section that heats the raw material gas or the processed gas flowing through the light irradiation region. The gas supply device according to any one of claims 1 to 4, characterized in that the ultraviolet light emitted from the light source exhibits a light intensity in a region with a wavelength of less than 230 nm. The gas supply device according to any one of claims 1 to 5, characterized in that the ultraviolet light emitted from the light source has a main emission wavelength of less than 230 nm. The gas supply device according to any one of claims 1 to 6, characterized in that the source material is a material containing oxygen atoms.

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