JP5303891B2 - Excimer lamp - Google Patents

Description

  The present invention relates to an excimer lamp including a discharge vessel made of silica glass and having a pair of electrodes provided in a state where the silica glass forming the discharge vessel is interposed to generate excimer discharge inside the discharge vessel.

  In recent years, for example, by irradiating a vacuum ultraviolet light having a wavelength of 200 nm or less onto a target object made of metal, glass and other materials, the target object is processed by the action of the vacuum ultraviolet light and ozone generated thereby. Technology, for example, a cleaning processing technology for removing organic contaminants attached to the surface of the object to be processed and an oxide film forming processing technology for forming an oxide film on the surface of the object to be processed have been developed and put into practical use.

As an apparatus for irradiating vacuum ultraviolet light, for example, an apparatus that forms an excimer molecule by excimer discharge and radiates from the excimer molecule, for example, an excimer lamp that uses light having a wavelength of around 170 nm is used as a light source. In such excimer lamps, many attempts have been made to efficiently radiate higher-intensity ultraviolet rays.
Specifically, for example, referring to FIG. 6, a discharge vessel (51) made of silica glass that transmits ultraviolet rays is provided, and electrodes (55, 56) are provided inside and outside the discharge vessel (51), respectively. In the excimer lamp (50) provided with the above, it is described that an ultraviolet reflective film (20) is formed on the surface exposed to the discharge space (S) of the discharge vessel (51). Examples of the material include those composed only of silica particles and those composed only of alumina particles (see Patent Document 1).
In this excimer lamp (50), a light emitting portion (58) that emits ultraviolet rays generated in the discharge space (S) because the ultraviolet reflecting film (20) is not formed on a part of the discharge vessel (51). ) Is formed.

  According to the excimer lamp (50) having such a configuration, the ultraviolet reflective film is provided on the surface of the discharge vessel (51) that is exposed to the discharge space (S), whereby the ultraviolet reflective film is provided. In the region, the ultraviolet rays generated in the discharge space (S) are reflected by the ultraviolet reflecting film, so that the ultraviolet rays pass through the silica glass in the region constituting the light emitting part (58) without entering the silica glass. Therefore, basically, the ultraviolet rays generated in the discharge space (S) can be used effectively, and the silica constituting the region other than the light emitting portion (58) can be used. It is said that damage due to ultraviolet distortion of glass can be suppressed to a small extent, and the occurrence of cracks can be prevented.

Japanese Patent No. 3580233

In recent years, further improvement in processing efficiency has been demanded as one of the demands for an apparatus that irradiates vacuum ultraviolet light equipped with an excimer lamp. It is conceivable to use light having a short wavelength effectively. This is because light having a short wavelength has a large energy, and thus a large effect can be obtained even with a small amount of light.
However, since the conventional ultraviolet reflecting film of an excimer lamp does not have a reflection characteristic with respect to light having a wavelength of around 150 nm, for example, the above-mentioned demand cannot be achieved.

Therefore, the present inventors can form an ultraviolet reflecting film that can reflect light having a wavelength of about 150 nm even if it is a small amount, and can efficiently use the light having the wavelength, for example, It was considered that the processing capability of an apparatus that radiates vacuum ultraviolet light equipped with an excimer lamp could be improved, and the present invention was completed.
An object of the present invention is to provide an excimer lamp that can effectively use light having a short wavelength near 150 nm and can be configured to have high processing capability.

The excimer lamp of the present invention includes a discharge vessel made of synthetic quartz glass having a discharge space, a pair of electrodes are provided in a state where the synthetic quartz glass forming the discharge vessel is interposed, and xenon gas is introduced into the discharge space. An excimer lamp that is sealed in a range of 10 to 60 kPa and generates excimer discharge in the discharge space of the discharge vessel,
An ultraviolet reflecting film made of silica particles and alumina particles is formed on the surface exposed to the discharge space of the discharge vessel, and the concentration of impurity metals other than silicon and aluminum contained in the ultraviolet reflecting film is 700 wtppm or less. der is, not the ultraviolet reflection film is only the light in the vicinity of a wavelength 170 nm, also characterized Rukoto to have a reflection characteristic for light near a wavelength of 150 nm.

  According to the excimer lamp of the present invention, the ultraviolet reflective film is composed of silica particles and alumina particles, and the concentration of impurity metals other than silicon and aluminum is 700 wtppm or less, so that the ultraviolet reflective film has a wavelength of around 170 nm. It can be configured to have a function of reflecting not only light but also light having a shorter wavelength near 150 nm, and the silica glass forming the discharge vessel transmits light having a wavelength of 140 to 150 nm or more. Therefore, it is possible to efficiently emit vacuum ultraviolet light generated by excimer discharge. Therefore, it is possible to effectively use vacuum ultraviolet light including light having a short wavelength near 150 nm having a large energy amount. It can be configured as having processing capability.

FIG. 1 is an explanatory cross-sectional view showing an outline of the configuration of an example of an excimer lamp according to the present invention, wherein (a) a cross-sectional view showing a cross section along the longitudinal direction of a discharge vessel, and (b) in (a). It is AA sectional view.
This excimer lamp 10 includes a hollow discharge vessel 11 having a rectangular cross section in which both ends are hermetically sealed and a discharge space S is formed therein. Xenon gas is enclosed as a discharge gas. Here, the amount of the xenon gas filled is such that the pressure falls within a range of 10 to 60 kPa (100 to 600 mbar), for example.
The discharge vessel 11 is made of silica glass, for example, synthetic quartz glass, which transmits vacuum ultraviolet light well, and has a function as a dielectric.

On the outer surface of the long side surface of the discharge vessel 11, a pair of grid-like electrodes, that is, one electrode 15 functioning as a high-voltage power supply electrode and the other electrode 16 functioning as a ground electrode extend in a long direction. Thus, the discharge vessel 11 functioning as a dielectric is interposed between the pair of electrodes 15 and 16.
Such an electrode can be formed, for example, by applying an electrode material made of metal to the discharge vessel 11 or by printing.

In this excimer lamp 10, when lighting power is supplied to one electrode 15, a discharge is generated between both electrodes 15 and 16 through the wall of the discharge vessel 11 functioning as a dielectric, and thereby excimer molecules As a result, an excimer discharge in which vacuum ultraviolet light is emitted from the excimer molecule occurs, and the sealed pressure of the xenon gas is, for example, in the range of 10 to 60 kPa (100 to 600 mbar). Vacuum ultraviolet light having a peak value is emitted.
Specifically, for example, as shown in FIG. 2 (a), when the sealed pressure of xenon gas is 50 mbar, the wavelength range from around wavelength 145 nm to wavelength 190 nm having a peak value P1 near the wavelength 150 nm. Light is emitted. In addition, as shown in FIG. 2 (b), when the sealed pressure of xenon gas is 100 mbar, the wavelengths from around the wavelength 145 nm to the wavelength 190 nm having the peak values P2 and P3 near the wavelength 150 nm and the wavelength 170 nm. Area light is emitted. FIG. 2C is an excimer discharge emission spectrum in the case where the sealed pressure of xenon gas is 680 mbar.
As described above, since the discharge vessel 11 is made of silica glass, particularly synthetic quartz glass with few impurities, the synthetic quartz glass has a characteristic of transmitting light having a wavelength of 140 to 150 nm or more. In the excimer lamp 10 having the above-described configuration in which the sealing pressure is in the range of 10 to 60 kPa (100 to 600 mbar), for example, the wavelength is 140 to 150 nm or more, and has peak values near the wavelength 150 nm and the wavelength 170 nm. Vacuum ultraviolet light is emitted.

Thus, in the excimer lamp 10, in order to efficiently use the vacuum ultraviolet light generated by excimer discharge, for example, the surface exposed to the discharge space S of the discharge vessel 11 is made of silica particles and alumina particles. An ultraviolet reflecting film 20 is provided.
The ultraviolet reflecting film 20 is, for example, an inner surface region corresponding to one electrode 15 functioning as a high-voltage power supply electrode on the long side surface of the discharge vessel 11 and a part of the inner surface region of the short side surface continuing to this region. The light emitting portion (aperture portion) 18 is formed by the absence of the ultraviolet reflecting film 20 in the inner surface region corresponding to the other electrode 16 that functions as the ground electrode on the long side surface of the discharge vessel 11. Is configured.
The film thickness of the ultraviolet reflecting film 20 is preferably 10 to 100 μm, for example.

The ultraviolet reflecting film 20 is at least a surface layer portion exposed to the discharge space S, that is, a silica particle can be melted by the influence of plasma generated by excimer discharge, and the grain boundary can disappear, for example, a depth of about 2 μm. In this range, the alumina particles are mixed with the silica particles, and can be constituted by a deposit of silica particles and alumina particles, for example.
Since the ultraviolet reflecting film 20 has a vacuum ultraviolet light transmission property in which the silica particles and the alumina particles themselves have a high refractive index, a part of the vacuum ultraviolet light reaching the silica particles or the alumina particles is the surface of the particles. And the other part is refracted and incident on the inside of the particle, and much of the light incident on the inside of the particle is transmitted (partially absorbed) and refracted when it is emitted again. It has a function of performing “diffuse reflection (scattering reflection)” in which such reflection and refraction occur repeatedly.
Further, since the ultraviolet reflecting film 20 is composed of silica particles and alumina particles, that is, ceramics, the ultraviolet reflecting film 20 does not generate an impure gas and has a characteristic that can withstand discharge.

As the silica particles constituting the ultraviolet reflective film 20, for example, silica glass made into fine powder particles can be used.
The silica particles have a particle size defined as follows within a range of 0.01 to 20 μm, for example, and the center particle size (peak value of the number average particle size) is, for example, 0.1 to 10 μm. Is preferable, and more preferably 0.3 to 3 μm.
Moreover, it is preferable that the ratio of the silica particle which has a center particle diameter is 50% or more.

The alumina particles constituting the ultraviolet reflecting film 20 have a particle diameter defined as follows within a range of 0.1 to 10 μm, for example, and have a center particle diameter (peak value of number average particle diameter). For example, it is preferably 0.1 to 3 [mu] m, more preferably 0.3 to 1 [mu] m.
Moreover, it is preferable that the ratio of the alumina particle which has a center particle diameter is 50% or more.

The “particle diameter” of the silica particles and the alumina particles constituting the ultraviolet reflecting film 20 refers to an approximately intermediate position in the thickness direction on the fracture surface when the ultraviolet reflecting film 20 is broken in the direction perpendicular to the surface. As a range, a magnified projection image is acquired by a scanning electron microscope (SEM), and a ferret (Feret) that is an interval between the parallel lines when arbitrary particles in the magnified projection image are sandwiched between two parallel lines in a certain direction. ) The diameter.
Specifically, as shown in FIG. 3 (a), when particles such as substantially spherical particles A and particles B having a pulverized particle shape are present alone, the particles are moved in a certain direction (for example, ultraviolet rays). The distance between the parallel lines when sandwiched between two parallel lines extending in the thickness direction of the reflective film 20 is defined as particle diameters DA and DB.
Further, for the particles C having a shape in which the particles of the starting material are melted and joined, as shown in FIG. 3 (b), each of the spherical portions in the portion distinguished from the particles C1 and C2 that are the starting materials, An interval between the parallel lines when measured between two parallel lines extending in a certain direction (for example, the thickness direction of the ultraviolet reflecting film 20) is measured, and these are set as the particle diameters DC1 and DC2.

  The “center particle diameter” of the silica particles and alumina particles constituting the ultraviolet reflecting film 20 is a range of particle diameters between the maximum value and the minimum value of the particle diameter of each particle obtained as described above, for example, 0. A center value of a section having a maximum number of particles (frequency) belonging to each section divided into a plurality of sections, for example, about 15 sections within a range of 1 μm.

  Since the silica particles and the alumina particles have a particle diameter in the above range, which is approximately the same as the wavelength of vacuum ultraviolet light, it is possible to efficiently diffuse and reflect vacuum ultraviolet light.

  Thus, in the excimer lamp 10 described above, since the ultraviolet reflecting film 20 includes alumina particles, impurity metals other than silicon that is the main component of silica particles and aluminum that is the main component of alumina particles are unavoidable. For example, in the relationship between the purity of the silica particles and the purity of the alumina particles, the mixing ratio of the silica particles and the alumina particles constituting the ultraviolet reflecting film 20 is adjusted to be within an appropriate range. Thus, the concentration (total) of impurity metals contained in the ultraviolet reflective film 20 is regulated to be 700 wtppm or less.

The ratio of the alumina particles contained in the ultraviolet reflecting film 20 is preferably, for example, 1 wt% or more, more preferably 5 wt% or more, and further preferably 10 wt% of the total of the silica particles and the alumina particles.
Moreover, it is preferable that it is 70 wt% or less of the sum total of a silica particle and an alumina particle, More preferably, it is 40 wt% or less.
Since the ultraviolet reflective film 20 is composed of the silica particles and the alumina particles in the above-mentioned mixing ratio, even when the ultraviolet light is lit for a long time, the silica particles are melted and the reflectance of the ultraviolet reflective film 20 is greatly increased. It is possible to reliably suppress the decrease, and the binding property (adhesiveness) of the ultraviolet reflective film 20 to the discharge vessel 11 due to the mixing of alumina particles does not significantly decrease. It is possible to reliably prevent the film 20 from being peeled off, and to set the impurity metal concentration to a predetermined value or less.

Such an ultraviolet reflective film 20 can be formed by a method called “flow-down method”, for example. That is, a dispersion vessel is prepared by mixing silica particles and alumina particles in a solvent having a combination of water and PEO resin (polyethylene oxide), and then pouring this dispersion into the discharge vessel formation material to form a discharge vessel. After adhering to a predetermined region on the inner surface of the material, the ultraviolet reflecting film 20 can be formed by evaporating water and the PEO resin by drying and baking. Here, the firing temperature is, for example, 500 to 1100 ° C.
For the production of the silica particles and the alumina particles used for forming the ultraviolet reflective film 20, any of a solid phase method, a liquid phase method, and a gas phase method can be used. Of these, submicron, A gas phase method, particularly chemical vapor deposition (CVD) is preferred because micron-sized particles can be obtained reliably.
Specifically, for example, silica particles are synthesized by reacting silicon chloride and oxygen at 900 to 1000 ° C., and alumina particles are synthesized by heating and reacting raw material aluminum chloride and oxygen at 1000 to 1200 ° C. The particle size can be adjusted by controlling the raw material concentration, the pressure in the reaction field, and the reaction temperature.

In general, in an excimer lamp, it is known that plasma is generated by excimer discharge. However, in the excimer lamp having the above-described configuration, the plasma is incident at a substantially right angle with respect to the ultraviolet reflection film. Therefore, if the temperature of the ultraviolet reflection film is locally rapidly increased and the ultraviolet reflection film is made of only silica particles, for example, the silica particles are melted by the heat of the plasma and the grain boundaries are In some cases, it is lost, and the vacuum ultraviolet light cannot be diffusely reflected, resulting in a decrease in reflectance.
However, since the ultraviolet reflecting film 20 is composed of silica particles and alumina particles, according to the excimer lamp 10 having the above configuration, basically, even when exposed to heat from plasma, Since alumina particles having a melting point higher than that of silica particles do not melt, the adjacent silica particles and alumina particles are prevented from being bonded to each other, and the grain boundary is maintained. Even in such a case, the vacuum ultraviolet light can be diffused and reflected efficiently, and the initial reflectance can be substantially maintained. In addition, since alumina particles have a higher refractive index than silica particles, it is possible to obtain a higher reflectance than an ultraviolet reflective film made only of silica particles.
Moreover, according to the excimer lamp 10 configured as described above, the concentration of the impurity metal excluding silicon, which is the main component of the silica particles contained in the ultraviolet reflecting film 20, and aluminum, which is the main component of the alumina particles, is 700 wtppm or less. Therefore, as shown in the result of an experimental example to be described later, the ultraviolet reflection film 20 can be configured to have reflection characteristics not only for light having a wavelength of about 170 nm but also for light having a wavelength of about 150 nm. Since the silica glass forming the discharge vessel has a characteristic of transmitting light having a wavelength of 140 to 150 nm or more, vacuum ultraviolet light having a peak in the vicinity of the wavelength of 150 nm and the wavelength of about 170 nm generated by excimer discharge is efficiently used. And has a high processing capacity.

  In addition, since the ultraviolet reflecting film 20 is formed on the inner surface of the discharge vessel 11 exposed to the discharge space S where excimer emission occurs, the silica glass in the region other than the light emitting portion 18 is exposed to vacuum ultraviolet rays in the discharge space S. Damage due to ultraviolet distortion caused by being incident on can be reduced, and the occurrence of cracks can be prevented.

Examples of experiments conducted to confirm the effects of the present invention will be described below.
[Experimental Example 1: Reflection characteristics of UV reflective film]
Three types of silica particles with a purity of 99.99%, 99.9% and a purity of 99.8%, and three types of silica particles with a purity of 99.99%, 99.9% and a purity of 99.8% Alumina particles are prepared, and the combination of silica particles and alumina particles is appropriately changed, and the mixing ratio of silica particles to alumina particles (silica particles: alumina particles) is within a range of 20:80 to 80:20. A plurality of types of test pieces were prepared by appropriately changing and forming an ultraviolet reflective film on a 1 mm thick substrate made of synthetic quartz glass by a flow-down method. Here, the baking temperature for forming the ultraviolet reflective film is 1100 ° C., and the film thickness is 30 μm.
The silica particles of any purity have a particle size range of 0.3 to 1.0 μm, a center particle size of 0.3 μm, and a ratio of particles having a center particle size of 50%.
Alumina particles of any purity have a particle size range of 0.2 to 0.7 μm, a center particle size of 0.4 μm, and a ratio of particles having a center particle size of 50%.
Regarding the ultraviolet reflective film in each test piece, the concentration of impurity metals other than silicon and aluminum contained in the ultraviolet reflective film was measured, and the reflected light intensity of light having a wavelength of 150 nm and the reflected light intensity of light having a wavelength of 170 nm were measured. Was measured. The results are shown in FIG.

<Measurement method of impurity metal concentration>
After the test piece is washed with pure water and dried, the test piece is weighed, and the portion of the test piece where the base material is exposed (the silica glass portion where the UV reflective film is not formed) is placed on the Teflon (registered trademark) tape. In this state, etching is performed by immersing in hydrofluoric acid and heating. When the ultraviolet reflective film on the test piece can no longer be visually confirmed, the test piece is taken out and weighed. The mass of the ultraviolet reflecting film is calculated by comparing the measured values of the test pieces before and after the etching process.
Next, a hydrofluoric acid solution containing silica particles (component) dissolved in hydrofluoric acid by etching, alumina particles left undissolved and granular, and an impurity metal component is heated. The silica component that has reacted with is evaporated as SiF ₄ , and the alumina component and the impurity component remaining as a residue are placed in a mixed acid composed of 6.5% of 85% phosphoric acid and 3.55 ml of 97% sulfuric acid, and then microwaved. After the alumina component and the impurity component are dissolved in an oven, pure water is added to dilute the solution to a total of 30 ml.
Then, the mass of the impurity metal is measured based on the concentration of the impurity metal in the diluted solution by the ICP emission spectroscopic analyzer, and according to the mass ratio of the impurity metal to the mass 0.5 g of the ultraviolet reflective film as the measurement target, The concentration of residual impurity metal contained in the ultraviolet reflecting film can be obtained.

  For example, the impurity metal components and their concentrations in an ultraviolet reflective film composed of 30 wt% silica particles having a purity of 99.99% and 70 wt% alumina having a purity of 99.8% are as follows: As shown in Table 1 below. Note that the impurity metal refers to an element belonging to an alkaline earth metal including beryllium and magnesium, or a transition metal.

<Measurement method of reflected light intensity>
For the UV reflective film, “VM-502” manufactured by ACTON RESEARCH was used to measure the reflected light intensity of light having a wavelength of 150 nm and the reflected light intensity of light having a wavelength of 170 nm. The measuring unit in this apparatus is configured by a direct incidence optical system as shown in FIG. 5, for example, and a deuterium lamp 60 that emits continuous light from light having a wavelength of 120 nm or less to visible light is used as a light source. ing. In this apparatus, the light emitted from the deuterium lamp 60 is once applied to the concave grating 61, then passed through the slit 62, irradiated to the test piece TS, and reflected light (reflected by the test piece TS ( The intensity of the reflected light with respect to light of a specific wavelength is integrated by integrating the measured value obtained by causing the photomultiplier 65 to receive light while adjusting the angle of the light receiving surface within the range of 0 ° to 180 °. Is obtained.
The measurement method of the reflected light intensity will be specifically described. First, with respect to a base material (synthetic quartz glass) that does not have an ultraviolet reflection film, the reflected light intensity (150 nm wavelength light and 170 nm wavelength light in the scattered light ( Reference value) is obtained in advance, and then a test piece on which an ultraviolet reflecting film is formed is set, and the reflected light intensity of each of the scattered light having a wavelength of 150 nm and the light having a wavelength of 170 nm is measured. By dividing each obtained measurement value by a reference value (measurement value of a substrate not having an ultraviolet reflective film), reflected light intensity of light having a wavelength of 150 nm and reflected light intensity of light having a wavelength of 170 nm are obtained. It is done.

As is clear from the results shown in FIG. 4, it was found that the reflected light intensity at a wavelength of 150 nm, the reflected light intensity of light at a wavelength of 170 nm, and the impurity metal concentration are linearly related and can be approximated by a straight line. .
The impurity metal concentration when the reflected light intensity of 150 nm light is 0.000 is 700 wtppm, and the impurity metal concentration when the reflected light intensity of 170 nm light is 0.000 is 1181 wtppm, Therefore, by controlling the concentration of the impurity metal contained in the ultraviolet reflecting film to be at least 700 wtppm or less, it is possible to surely have a function of reflecting not only 170 nm light but also 150 nm light. confirmed.
Therefore, in an actual excimer lamp, the ultraviolet reflective film is one in which the impurity metal concentration is regulated to 700 wtppm or less, so that vacuum ultraviolet light including light having a wavelength of 150 nm generated by excimer discharge is efficiently used. Will be able to.

[Experiment 2]
An ultraviolet reflective film comprising silica particles having a purity of 99.9% and alumina particles having a purity of 99.8%, the content ratio of the alumina particles being changed to 0 wt%, 10 wt%, 33 wt%, and 50 wt% Were formed by a flow-down method on a substrate having a thickness of 30 μm and a thickness of 1 mm made of flat synthetic quartz glass, thereby preparing four types of test pieces.
And about each test piece, when the ultraviolet reflective film is heated to 1000 ° C. and when heated to 1300 ° C., the reflected light intensity of light having a wavelength of 170 nm in each case is “VM-502” manufactured by ACTON RESEARCH. When the content ratio of alumina particles in the ultraviolet reflective film is 0 wt%, that is, when alumina particles are not included, this corresponds to the firing temperature when forming the ultraviolet reflective film. When heated to 1300 ° C., which is a temperature corresponding to the heating temperature when plasma is applied to the ultraviolet reflective film, with respect to the reflected light intensity when heated to 1000 ° C., the temperature of the reflected light, As a result, it was confirmed that in an actual excimer lamp, the ultraviolet reflective film has a At the place where the laser hit, the intensity of the reflected light locally decreases, the illuminance distribution of the excimer lamp becomes uneven, and when the excimer lamp is lit for a long time, the plasma hits the entire UV reflection film and the reflection is reflected. It is assumed that the rate will decline.

On the other hand, in the case where 10 wt% of alumina particles are added, even when heated to 1300 ° C., the reflected light intensity is higher than in the case where no alumina particles are added, and the reflectivity of the ultraviolet reflecting film due to heat is high. It was confirmed that the degree of decrease in the resistance can be suppressed by about 70%. As the content ratio of the alumina particles increases, the degree of decrease in the reflectivity of the ultraviolet reflecting film due to heat can be suppressed to a small level. For example, in the case where 50 wt% of alumina particles are added, it is heated to 1000 ° C. It was confirmed that the reflected light intensity at the time coincided with the reflected light intensity when heated to 1300 ° C., and it was possible to suppress the decrease in the reflectance of the ultraviolet reflecting film due to heat.
Therefore, in an actual excimer lamp, since the ultraviolet reflection film is made by adding 10 wt% or more of alumina particles, the excimer lamp is lit for a long time and the ultraviolet reflection film is exposed to the heat of the plasma. However, it is possible to suppress a decrease in reflectance due to melting of the silica particles.
In addition, all the ultraviolet reflective films containing alumina particles in the test piece prepared in Experimental Example 2 have an impurity metal concentration of 700 wtppm or less.

As mentioned above, although embodiment of this invention was described, this invention is not limited to said embodiment, A various change can be added.
The present invention is not limited to the excimer lamp having the above-described configuration, but is also applied to a double-tube excimer lamp as shown in FIG. 6 and a so-called “square” excimer lamp as shown in FIG. Can be applied.
An excimer lamp 50 shown in FIG. 6 has a cylindrical outer tube 52 made of silica glass and an outer diameter smaller than the inner diameter of the outer tube 52 disposed along the tube axis in the outer tube 52, for example. A cylindrical inner tube 53 made of silica glass, and the outer tube 52 and the inner tube 53 are melt-bonded at both ends to form an annular discharge space S between the outer tube 52 and the inner tube 53. A discharge vessel 51 having a double tube structure is provided. One electrode (high voltage supply electrode) 55 made of, for example, metal is provided in close contact with the inner peripheral surface of the inner tube 53, and for example, a wire mesh or the like. The other electrode 56 made of a conductive material is provided in close contact with the outer peripheral surface of the outer tube 52, and a discharge gas that forms excimer molecules in the discharge space S by excimer discharge such as xenon gas is provided. Is Hama, have been constructed.
In the excimer lamp 50 having such a configuration, for example, the ultraviolet reflecting film 20 is provided over the entire inner surface of the inner tube 53 of the discharge vessel 51, and a light emitting portion 58 is formed on the inner surface of the outer tube 52. The ultraviolet reflective film 20 is provided except for a part of the region.

The excimer lamp 40 shown in FIG. 7 includes a discharge vessel 41 having a rectangular cross section made of, for example, synthetic silica glass, and a pair of outer electrodes 45, 45 made of metal are discharged on opposite outer surfaces of the discharge vessel 41. The discharge vessel 41 is filled with, for example, xenon gas, which is a discharge gas, and is disposed so as to extend in the tube axis direction of the vessel 41. In FIG. 7, reference numeral 42 denotes an exhaust pipe, and reference numeral 43 denotes a getter made of, for example, barium.
In the excimer lamp 40 having such a configuration, the ultraviolet reflective film 20 is provided on the inner surface of the discharge vessel 41 over a region corresponding to each of the outer electrodes 45 and 45 and one inner surface region continuous with these regions. In addition, the light emitting portion 44 is formed by not providing the ultraviolet reflecting film 20.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing for description which shows the outline of the structure in an example of the excimer lamp of this invention, Comprising: (a) Sectional drawing which shows the cross section along the longitudinal direction of a discharge vessel, (b) AA sectional view in (a) FIG. It is a graph which shows the excimer discharge emission spectrum in the excimer lamp with which xenon gas was enclosed. It is explanatory drawing for demonstrating the definition of the particle diameter of a silica particle and an alumina particle. It is a graph which shows the relationship between the reflected light intensity | strength about the light of a specific wavelength, and the density | concentration of the impurity metal contained in an ultraviolet reflective film about the ultraviolet reflective film produced in the experiment example. It is a figure for demonstrating the measurement principle of the apparatus used in order to measure the reflected light intensity | strength about the ultraviolet reflective film produced in the experiment example. It is sectional drawing for description which shows the outline of the structure in the other example of the excimer lamp of this invention, Comprising: (a) The cross-sectional view which shows the cross section along the longitudinal direction of a discharge vessel, (b) A- in (a) It is A sectional view. It is sectional drawing for description which shows the outline of the structure in the further another example of the excimer lamp of this invention, Comprising: (a) Sectional drawing which shows the cross section along the longitudinal direction of a discharge vessel, (b) On the paper surface of (a) It is sectional drawing which shows the cross section by a perpendicular plane.

Explanation of symbols

10 Excimer lamp 11 Discharge vessel 15 One electrode (high voltage supply electrode)
16 The other electrode (ground electrode)
18 Light emitting part (aperture part)
20 UV reflective film 40 Excimer lamp 41 Discharge vessel 42 Exhaust tube 43 Getter 44 Light emitting portion 45 Outer electrode 50 Excimer lamp 51 Discharge vessel 52 Outer tube 53 Inner tube 55 One electrode (high voltage supply electrode)
56 Other electrode 58 Light emitting portion 60 Deuterium lamp 61 Concave grating 62 Slit 65 Photomal TS Test piece S Discharge space

Claims (1)

A discharge vessel made of synthetic quartz glass having a discharge space is provided, and a pair of electrodes are provided in a state where the synthetic quartz glass forming the discharge vessel is interposed, and the xenon gas is filled in the discharge space with an encapsulation pressure of 10 to 60 kPa. An excimer lamp that generates an excimer discharge in the discharge space of the discharge vessel,
An ultraviolet reflecting film made of silica particles and alumina particles is formed on the surface exposed to the discharge space of the discharge vessel, and the concentration of impurity metals other than silicon and aluminum contained in the ultraviolet reflecting film is 700 wtppm or less. der is, not the ultraviolet reflection film is only the light near a wavelength of 170 nm, an excimer lamp, wherein Rukoto that have a reflection characteristic for light near a wavelength of 150 nm.

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