JP2012212576A - Light irradiation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light irradiation device which can enhance the adsorption performance of a getter in an excimer lamp, which is internally provided with a fluorescent substance or a reflection film, even in a state where the excimer lamp is cooled.SOLUTION: The light irradiation device comprises a long excimer lamp where a pair of electrodes are arranged on the external surface of a discharge vessel having the internal surface provided with a fluorescent substance, an outer tube composed of a light permeable material and provided so that the excimer lamp is inserted therein, and a cooler which supplies cooling air from one end of the excimer lamp toward the other end thereof. The excimer lamp is provided with a getter at the other end thereof in the discharge vessel.

Description

  The present invention relates to a light irradiation apparatus using an excimer lamp equipped with a getter as a light source, and more particularly to a light irradiation apparatus used in a manufacturing process of a liquid crystal display.

  At present, excimer lamps are used for substrate cleaning in the manufacturing process of a semiconductor integrated circuit or a liquid crystal display. An excimer lamp is a lamp in which a rare gas is sealed as a luminescent gas in a discharge vessel and emits unique ultraviolet light caused by the luminescent gas.

In an excimer lamp, when impurities such as hydrogen, oxygen, and carbon monoxide are contained in the discharge vessel, extra discharge occurs in the discharge vessel, and the originally required light emission efficiency of ultraviolet light is reduced.
As means for removing impurities from the inside of the discharge vessel, a process of heating the discharge vessel to a high temperature and evacuating impurities inside the discharge vessel (hereinafter referred to as hot evacuation) has been performed. For example, the discharge vessel was heated at 800 degrees for 5 hours, and then the atmosphere in the discharge vessel was exhausted to remove impurities.

  Japanese Unexamined Patent Application Publication No. 2010-256515 describes an excimer lamp used for forming an alignment film in the manufacturing process of a liquid crystal display. The excimer lamp used for the application requires irradiation with ultraviolet light having a wavelength of 300 to 360 nm, and light having a shorter wavelength damages the liquid crystal. Therefore, a specific phosphor is usually provided on the inner surface of the discharge vessel. The phosphor is applied with vacuum ultraviolet light generated in a discharge vessel, and ultraviolet light of 300 to 360 nm is irradiated from the phosphor.

  However, the excimer lamp described above has a phosphor coated in the discharge vessel, and in order to avoid the phosphor from evaporating and disappearing during the warm evacuation, the hot evacuation can be performed only at a low temperature where the phosphor does not evaporate. Absent. For example, warm exhaust can be performed only at 600 degrees or less. However, impurities cannot be sufficiently removed by hot exhaust at 600 degrees or less.

  For this reason, a getter for removing impurities is provided inside the discharge vessel of the excimer lamp, and impurities generated in the discharge vessel can be removed by the adsorption function of the getter. Japanese Patent No. 2951139 discloses an excimer lamp having a getter.

A light irradiation device 91 used in the manufacturing process of the liquid crystal display is shown in FIG.
The light irradiation device 91 is required to irradiate the liquid crystal target object W0 with ultraviolet light at a high illuminance, while the liquid crystal target object is not exposed to a high temperature. It has been. For example, heat or radiant heat generated when the excimer lamp is turned on has a thermal effect on the liquid crystal object W0, which hinders liquid crystal display manufacture. Therefore, the light irradiation device 91 is provided with a cooling device 932 for removing the influence of heat on the object to be processed W0.

  However, the cooling device 932 provided in the light irradiation device 91 has been found to have a problem that the adsorption function of the getter provided in the excimer lamp 95 is lowered. The getter used in the present invention has higher chemical reaction and decomposition reaction when the temperature is higher, and the amount of adsorption and the adsorption speed of the getter are improved. However, the getter cooled more than necessary by the cooling device has a reduced adsorption speed and discharge. This makes it difficult to remove sufficient impurities in the container.

JP 2010-256515 A Japanese Patent No. 2951139

  In view of the above problems, an object of the present invention is to provide a light irradiation apparatus having an excimer lamp including a phosphor and a reflection film therein, and to suppress a decrease in getter adsorption performance even when the excimer lamp is cooled. It is providing the light irradiation apparatus which can be performed.

In order to solve the above-mentioned problem, an invention according to claim 1 is directed to a long excimer lamp including a discharge vessel provided with a fluorescent material on an inner surface and a pair of electrodes on an outer surface, and the excimer lamp. In a light irradiation device comprising: an outer tube made of a light-transmitting material provided in a state of being inserted inside; a cooling device that blows cooling air from one end of the excimer lamp toward the other end; and The excimer lamp is a light irradiation device characterized in that a getter is provided at the other end inside the discharge vessel.
The invention according to claim 2 is characterized in that a reflection film made of silica particles is formed between the inner wall of the discharge vessel and the fluorescent material. It is what.
According to a third aspect of the present invention, the getter is a light irradiation apparatus according to the first or second aspect, wherein a getter material is supported on a support.
The invention according to claim 4 is the light irradiation apparatus according to claim 3, wherein the getter is a thin film in which the getter material is deposited on an inner wall surface of a discharge vessel.
According to a fifth aspect of the present invention, a getter chamber for providing the getter is provided inside the discharge vessel, and the support is fixed to the outer periphery of the getter chamber outside the discharge vessel. The light irradiation apparatus according to claim 3, wherein a magnetic member is provided.

  The getter used in the present invention has different getter adsorption speeds in the use environment of the getter at a temperature difference of several degrees to 100 degrees, and when the getter becomes hot to such a temperature difference, Those exhibiting the property of improving the adsorption rate are used.

According to the first aspect of the present invention, a long excimer lamp in which a pair of electrodes are arranged on the outer surface of a discharge vessel provided with a fluorescent material on the inner surface, and the excimer lamp inserted therein is provided. In the light irradiation device, the excimer lamp includes a discharge vessel, and an outer tube made of a light-transmitting material, a cooling device that blows cooling air from one end of the excimer lamp toward the other end, and Since the getter is provided at the other end of the inside, the cooling of the getter by the cooling air is alleviated, and more impurities inside the discharge vessel can be removed.
According to the second aspect of the present invention, since the reflection film made of silica particles is formed on the inner surface of the discharge vessel, the light irradiation from the excimer can be effectively used and impurities generated from the silica particles Can be removed by a getter.
According to the invention described in claim 3, the getter material can be reliably and simply inserted into the discharge vessel by the getter material being held by the support.
According to the invention described in claim 4, since the getter is a thin film in which the getter material is deposited on the inner wall surface of the discharge vessel, the adsorption area of the getter can be provided in a wide area.
According to a fifth aspect of the invention, the excimer lamp has a magnetic member for fixing the support to the outside of the discharge vessel, so that the support vibrates and damages the inside of the discharge vessel. There is nothing.

(A) The schematic of the excimer lamp attached to the light irradiation apparatus of this invention, (b) AA sectional drawing of an excimer lamp is shown. The external view of the light irradiation apparatus of this invention is shown. The external view of the getter which concerns on this invention is shown. Sectional drawing of the charging process of the getter of the excimer lamp which concerns on this invention is shown. The experimental result about the change of the illumination intensity maintenance factor with respect to the lighting time of a lamp is shown. The external view of the conventional light irradiation apparatus is shown. Sectional drawing of the excimer lamp edge part installed in the light irradiation apparatus of this invention is shown.

Hereinafter, embodiments of the light irradiation apparatus of the present invention will be described.
FIG. 1A shows a schematic diagram of an excimer lamp attached to the light irradiation apparatus of the present invention, and FIG. 1B shows a cross-sectional view of the excimer lamp taken along the line AA. An explanatory view of the light irradiation apparatus of the present invention is shown in FIG.

  First, the excimer lamp attached to the light irradiation apparatus of this invention is demonstrated. The excimer lamp 5 is provided with an external electrode 52 on the outer surface of the discharge vessel 51, a reflective film 53 and a phosphor 54 are applied on the inner surface, and one end of the discharge vessel 51 is used to remove impurities in the discharge vessel. The getter chamber 55 is provided, and the getter chamber 55 is provided with a getter 56. A partition wall 57 is provided between the getter chamber 55 and the discharge space S, and a vent hole 58 is formed in the partition wall 57.

  In the discharge vessel 51 of the excimer lamp 5, a reflective film 53 and a phosphor 54 are applied. These applied substances contain a lot of impurities, and there is a high demand for removing impurities. Further, since the phosphor is applied, the hot exhaust cannot be sufficiently performed, and the impurity removal by the warm exhaust cannot be sufficiently expected. Therefore, in the excimer lamp having the above-described configuration, the need for a getter provided in the discharge vessel is high, and the light irradiation apparatus of the present invention that can improve the adsorption performance of the getter is significant.

Examples of the phosphor include europium activated strontium borate (Sr—B—O: Eu (hereinafter referred to as SBE)) phosphor, cerium activated lanthanum magnesium aluminate (La—Mg—Al—O: Ce (hereinafter, LAM))) phosphor, gadolinium, praseodymium-activated lanthanum phosphate (La-PO: Gd, Pr (hereinafter referred to as LAP: Pr, Gd)) phosphor, and the like.
In addition, particles having high ultraviolet light reflectivity are used for the reflective film, for example, silica (SiO ₂ ) particles or alumina (Al ₂ O ₃ ) particles.

  The light irradiation apparatus of the present invention is shown in FIG. The light irradiation device 1 of the present invention includes a radiator 3 for cooling the atmosphere, a cooling device 32 including a cooling fan 2 for sending cooling air, an electrical equipment chamber 4 for housing a control circuit, and ultraviolet light. An excimer lamp 5 is provided. An outer tube 7 made of a light transmitting material is provided on the outer periphery of the excimer lamp 5, and both ends of the excimer lamp 5 are disposed so as to protrude from the outer tube 7. A cooling air passage 6 is formed to pass through. The cooling air flows from one end 81 of the excimer lamp 5 toward the other end 82, and a getter chamber 55 is provided at the other end of the excimer lamp.

  The air cooled by the radiator 3 is blown by the cooling fan 2 and flows through the cooling air passage 6, and this cooling air is blown from one end portion 81 of the excimer lamp 5 toward the other end portion 82. That is, the excimer lamp 5 is attached to the light irradiation device so that the getter chamber 55 is disposed on the downstream side of the cooling air.

The excimer lamp 5 is installed in the light irradiation device 1 through the lamp holder 8. Further, an outer tube 7 made of a light transmissive material is provided on the outer periphery of the excimer lamp 5, and ultraviolet light emitted from the excimer lamp 5 is irradiated to the workpiece W 1 through the outer tube 7.
At this time, if radiant heat is generated from the excimer lamp 5 or the outer tube 7 toward the work W1, the temperature of the work W1 is increased, the uniformity of the in-plane temperature of the work W1 is disturbed, and the work W1 is defective. For this reason, the light irradiation device 1 located above the workpiece W1 is provided with a cooling device 32, and the excimer lamp 5 and the outer tube 7 are cooled by the cooling device 32, so that the workpiece W1 from the excimer lamp 5 and the outer tube 7 is cooled. The influence of radiant heat on the is suppressed.

As shown in FIG. 7, it is preferable that the excimer lamp 5 mounted on the light irradiation apparatus 1 of the present invention is designed so that the periphery of the getter chamber 55 is covered with the base member 9. With such a configuration, the base member 9 prevents the outer wall around the getter chamber 55 from being directly exposed to the cooling air from the cooling device 32, and produces an effect that the cooling of the getter by the cooling air is alleviated.
Moreover, it is preferable that the base member 9 covering the getter chamber 55 is designed to be covered with the lamp holder 8 when the excimer lamp 5 is attached to the light irradiation device 1 of the present invention. Such a configuration produces an effect of further reducing the cooling of the getter by the cooling air.

  For the base member 9 of the present invention, a member excellent in insulation, heat resistance, and deterioration resistance against ultraviolet rays is preferable, and a ceramic material is suitable. In addition, the lamp holder 8 is preferably a member that is excellent in insulation and deterioration resistance against ultraviolet rays and has high heat retention, and a ceramic material or a resin material is suitable. For example, PTFE is used.

  In the light irradiation device 1 of the present invention shown in FIG. 2, the cooling air flows from one end 81 of the excimer lamp 5 toward the other end 82, and the outer tube provided on the outer periphery of the excimer lamp 5 or the excimer lamp. 7 is cooled. A getter chamber 55 is provided at the other end of the excimer lamp 5, and a getter 56 is inserted into the getter chamber 55.

The excimer lamp 5 has a large overall length, for example, about 3000 mm, and when the excimer lamp 5 is cooled with cooling air, a temperature difference occurs between both end portions 81 and 82 of the excimer lamp 5. From the configuration of FIG. 2, one end portion 81 is further cooled, and the other end portion 82 is more easily kept warm than the one end portion 81. For this reason, the getter 56 provided at the other end portion 82 is less deteriorated in the adsorption function of the getter 56 due to cooling than when provided at the one end portion 81, and more impurities in the discharge vessel can be removed.
In this way, by arranging the getter at the optimum position, the illuminance maintenance rate of the ultraviolet light from the excimer lamp is significantly changed, leading to a longer life of the excimer lamp.

A getter according to the present invention is shown in FIG. FIG. 3A shows a case where a getter material is carried on a flat support, and FIG. 3B shows a case where a getter material is carried on a cup-like support. The getter 56 includes a getter material 561 and a support 562 for holding and transporting the getter material 561.
Examples thereof include a non-evaporable getter material that the getter 56 is installed in a container to function, and an evaporable getter material deposited as a thin film on the inner wall surface of the container. For example, a Zr alloy can be used as a non-evaporable getter, and a Ba alloy can be used as an evaporable getter.

The getter material 561 used in the present invention is appropriately selected depending on the temperature environment of the getter chamber 55 at the time of use. For example, in a temperature environment of 100 ° C. to 300 ° C. when the lamp is lit, a getter material that efficiently adsorbs an impure gas at that temperature is selected as the getter material used in the present invention.
In addition, the getter used in the present invention has a different getter adsorption rate when the use environment of the getter is a temperature difference of several degrees to about 100 ° C., and the getter on the low temperature side having the temperature difference has a high temperature. As the getter on the side, the getter on the high temperature side that exhibits a higher adsorption rate than the getter on the low temperature side is used.

  In the case of using an evaporative getter, as illustrated in FIG. 1, a part of the evaporated getter may enter the discharge space S through the vent hole 58. In this case, since the getter may induce a lightning-like discharge in the discharge space, the distance L between the getter chamber 55 and the discharge space S formed between the external electrodes 52 is set to be sufficiently long. Prevents induction of discharge.

A procedure for manufacturing the getter chamber 55 is shown in FIG. FIG. 4A shows an end cross-sectional view of the excimer lamp when the getter 56 is inserted into the getter chamber 55, and FIG. 4B shows the gas inlet 59 sealed after the getter 56 is inserted. FIG. 4C shows an end cross-sectional view when a getter material is deposited on the inner wall surface of the discharge vessel to form a thin film.
A partition wall 57 is provided at one end of the excimer lamp 5, and a gas inlet 59 is provided at the end. A getter 56 is inserted into the getter chamber 55 through the gas inlet 59. Then, after exhausting the atmosphere in the discharge vessel, xenon gas is sealed in the discharge vessel, the gas inlet 59 is closed, and the discharge vessel is sealed. After sealing, the getter chamber 55 is heated according to the getter material 561 to activate the getter material.
When an evaporative getter is used as the getter described above, as shown in FIG. 4C, the getter material is evaporated from the support 562 holding the getter material and deposited on the inner wall surface of the discharge vessel to form the thin film 560. Form. Thereby, the adsorption area of a getter can be provided in a wide area.

The support 562 holding the getter material is left in the getter chamber. The support 562 is affected by the cooling air from the cooling device and vibrates while the lamp is lit, which may damage the getter chamber and destroy the inside of the discharge vessel.
Therefore, by using a magnetic member as the material of the support body 562, providing the magnetic member 563 on the outer periphery of the getter chamber 55, and fixing the support body 562 in the getter chamber with a magnetic force, vibration of the support body 562 can be suppressed. Such a magnetic member can be provided on the wall surface of the discharge vessel positioned on the outer periphery of the getter chamber 55 or on the lamp holder 8 positioned on the outer periphery of the getter chamber 55.

  Hereinafter, specific examples of the present invention will be described, but the present invention is not limited thereto.

[Example 1]
According to the configuration shown in FIGS. 1 and 2, a light irradiation apparatus according to the present invention was manufactured under the following conditions.

The excimer lamp provided in the light irradiation device has a total length of 2800 mm, vertical and horizontal dimensions of 43 mm × 15 mm, a lamp output of 2 kW, a discharge vessel made of quartz glass, a phosphor constituting the phosphor layer is SBE, and xenon as a luminescent gas The excimer lamp is filled with gas. The outer tube is made of quartz glass, has a total length of 2500 mm, an inner diameter of 76 mm, and a thickness of 2.5 mm.
The cooling fan is an axial fan having an air blowing capacity capable of supplying an air blowing amount of, for example, 4 m ³ / min to one light source. The pressure in the air guiding space is 500 to 1000 Pa, the temperature of the cooling air is 30 degrees, and the temperature of the wind in the exhaust air space is about 60 degrees.
In the excimer lamp provided in the light irradiation device, the cooling air from the cooling device flows from one end 81 on the upstream side of the cooling air to the other end 82 on the downstream side. At this time, the getter chamber and the getter Is provided at the other end 82 on the downstream side of the cooling air.
The getter used in the present invention is a non-evaporable Ba—Al alloy as a getter material, and is an evaporative getter used in a relatively low temperature environment of 150 ° C. to 500 ° C. This getter was carried on a support and inserted into the getter chamber, and as a pretreatment, the getter and the support were heated at 1100 degrees to activate the getter.
The object to be processed is a test liquid crystal panel material having vertical and horizontal dimensions of 2200 mm × 2500 mm, and the separation distance between the light source unit and the work W1 that is the object to be processed is 400 mm.
When lit under the above conditions, one end 81 of the excimer lamp was around 40 degrees and the other end 82 was around 80 degrees.

[Comparative Example 1]
In Example 1, a similar light irradiation apparatus was manufactured except that the getter chamber and the getter of the excimer lamp attached to the light irradiation apparatus were provided at one end 81 instead of the other end 82. .

[Comparative Example 2]
In Example 1, the same light irradiation apparatus was produced except that the excimer lamp attached to the light irradiation apparatus was not provided with a getter chamber and a getter.

[Evaluation]
Using the light irradiation devices of Example 1, Comparative Example 1, and Comparative Example 2, the illuminance maintenance rate in the region of the wavelength of 300 nm to 400 nm was measured. The illuminance maintenance rate is obtained by measuring the illuminance with a spectrophotometer and dividing the measured value by the illuminance at the beginning of lighting. The illuminance maintenance rate of 100% means that the illuminance at the beginning of lighting is maintained. The measurement results are shown in FIG. It was confirmed that Example 1 and Comparative Example 1 in which an excimer lamp was provided with a getter exhibited a high illuminance maintenance rate over a long period of time compared with Comparative Example 2 in which no getter was provided. In addition, the first embodiment in which the excimer lamp getter is provided on the downstream side of the cooling air maintains an illuminance maintenance ratio of 90% or more for a long time, and the comparative example 1 in which the getter is provided on the upstream side of the cooling air. High illuminance maintenance rate was maintained. When the lighting time passed 3000 hours, Example 1 showed an illuminance maintenance rate 20% higher than that of Comparative Example 1.
From these results, it was confirmed that the illuminance maintenance rate can be dramatically improved by changing the position of the getter chamber and the getter from the upstream side to the downstream side of the cooling air.

In the present invention, when the lamp is cooled by the cooling air from the cooling device, the getter provided in the lamp is provided on the downstream side of the cooling air, thereby relaxing the cooling of the getter by the cooling air and improving the getter adsorption performance. be able to. Therefore, the installation location of the getter differs depending on the cooling air, and the getter is provided on the downstream side of the cooling air.

DESCRIPTION OF SYMBOLS 1 Light irradiation apparatus 2 Cooling fan 3 Radiator 32 Cooling apparatus 4 Electrical equipment room 5 Excimer lamp 51 Discharge vessel 52 External electrode 53 Reflective film 54 Phosphor 55 Getter room 56 Getter 560 Thin film 561 Getter material 562 Support body 563 Magnetic member 57 Partition wall 58 Vent hole 59 Gas inlet 6 Cooling air passage 7 Outer tube 8 Lamp holder 81 One end 82 The other end 9 Base member 91 Light irradiation device 92 Cooling fan 93 Radiator 932 Cooling device 95 Excimer lamp 97 Outer tube S Discharge space W1 Work W0 Object to be treated

Claims (5)

An elongate excimer lamp provided with a discharge vessel provided with a fluorescent substance on the inner surface and a pair of electrodes on the outer surface, and an outer material made of a light-transmitting material provided with the excimer lamp inserted inside. A light irradiation device comprising: a tube; a cooling device that blows cooling air from one end of the excimer lamp toward the other end; and
The excimer lamp is provided with a getter inside the discharge vessel and at the other end.   The light irradiation apparatus according to claim 1, wherein a reflection film made of silica particles is formed between an inner wall of the discharge vessel and the fluorescent material.   The light irradiation apparatus according to claim 1, wherein the getter has a getter material supported on a support.   The light irradiation apparatus according to claim 3, wherein the getter is a thin film in which the getter material is deposited on an inner wall surface of a discharge vessel. Inside the discharge vessel, a getter chamber for providing the getter is provided,
The light irradiation apparatus according to claim 3, wherein a magnetic member for fixing the support to the outer periphery of the getter chamber is provided outside the discharge vessel.

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