TWI466735B - Ultraviolet irradiation apparatus - Google Patents

Description

Ultraviolet irradiation device

The present invention relates to an ultraviolet irradiation device that is provided with a discharge lamp that irradiates ultraviolet rays toward a processing object, and a gas that supplies gas to a space between the discharge lamp and the object to be processed. Supply agency.

The ultraviolet irradiation device is a device that irradiates the object to be processed with ultraviolet rays having a short wavelength such as 172 nm to clean the object to be processed.

If oxygen is present in the environment, the above ultraviolet rays are significantly attenuated by this oxygen absorption.

For this reason, an inert gas such as nitrogen gas is supplied to a space between a discharge lamp that emits ultraviolet rays and an object to be processed, as disclosed in Japanese Laid-Open Patent Publication No. 2005-197291, to suppress the attenuation of ultraviolet rays.

As a method of supplying an inert gas to a space between the discharge lamp and the object to be processed, the discharge port is disposed of the discharge lamp and the discharge lamp simply by the downflow from the upper side of the discharge lamp. In addition to the method of supplying an inert gas to the object to be treated, it is also considered that, as disclosed in the following Japanese Patent Laid-Open Publication No. 2005-197291, the inert gas is not simply supplied by the downflow, but is blown at the inert gas. A method of disposing a diffusion plate for diffusing an inert gas with the discharge lamp to uniformly flow the inert gas is provided.

However, in the former method of supplying an inert gas simply by downflow, a powdery substance called so-called white powder may adhere to the surface of the discharge lamp.

This white powder is considered to be an oxide formed by the Si-based floating matter existing in the environment in which the ultraviolet irradiation device is installed, invades into the ultraviolet irradiation device, and reacts with ultraviolet rays emitted from the discharge lamp.

When the white powder adheres to the surface of the discharge lamp, the amount of ultraviolet light emitted from the discharge lamp is lowered by the absorption of ultraviolet rays by the white powder, and there is a problem that the object to be processed is defective, that is, particles or the like. .

Therefore, the user of the ultraviolet irradiation apparatus is required to perform the operation of regularly cleaning the white powder adhering to the discharge lamp, resulting in an increase in the management load of the apparatus.

Further, in the latter method in which a diffusion plate of an inert gas is disposed between the outlet of the inert gas and the discharge lamp, the adhesion of the white powder is suppressed, but the supply amount of the inert gas is the same as the former. Then, the amount of the inert gas blown to the discharge lamp is small, resulting in a decrease in the cooling effect on the discharge lamp. If the cooling effect on the discharge lamp is lowered, the temperature of the discharge lamp rises and the intensity of the emitted ultraviolet light decreases.

The present invention has been made in view of the above circumstances, and an object thereof is to reduce the management burden of the ultraviolet irradiation device as much as possible, and to efficiently irradiate the object to be treated with ultraviolet rays.

According to a first aspect of the invention, there is provided an ultraviolet ray irradiation device, comprising: a discharge lamp that emits ultraviolet ray toward the object to be processed; and a gas supply mechanism that supplies a gas to a space between the discharge lamp and the object to be processed. The gas supply mechanism includes an air outlet that is disposed on the side of the discharge lamp, and a shield that covers the space around the discharge lamp on the side opposite to the side where the object to be processed exists.

The inventors of the present invention conducted gas flow analysis in a configuration in which a gas was ejected from a blowing outlet toward a discharge lamp by a downflow, and as a result, it was confirmed that a swirl was generated in the flow of the gas ejected from the outlet. In particular, a vortex flow in a vertical direction that is rolled up above the discharge lamp.

The foreign intrusion of impurities is vortexed up to the top of the discharge lamp, and the rolled up impurities are then sprayed onto the discharge lamp by the downward flow of the gas, whereby the white powder adheres to the discharge lamp.

Therefore, it is preferable to eject the gas toward the discharge lamp from the air outlet disposed at a lower portion of the upper surface of the lamp than the side of the discharge lamp from the air outlet disposed on the side of the discharge lamp, thereby causing the discharge to be discharged to the discharge lamp. The above gas forms a laminar flow along the surface of the discharge lamp. In particular, when an external electrode type discharge lamp in which an earth side electrode is disposed on the lower surface of the discharge lamp and a high voltage side electrode is disposed on the upper surface of the lamp, it is difficult to blow because the high voltage is dangerous. The exit is near the discharge lamp. Therefore, it is preferred to provide a blowout port on the upper surface of the discharge lamp, particularly at the lower portion of the upper external electrode.

By directly spraying the gas to the discharge lamp in this manner, the discharge lamp is reliably cooled with a relatively small gas flow rate, thereby suppressing the decrease in the radiation intensity of the ultraviolet ray as the temperature of the discharge lamp rises.

Further, the adhesion of the white powder to the discharge lamp is suppressed by the clean flow of the layered gas along the surface of the discharge lamp.

The gas is ejected toward the discharge lamp, and it is preferable that the gas is sprayed onto the surface of the discharge lamp so that the gas forms a layered flow along the surface of the discharge lamp. The reason for this is that the adhesion of the white powder to the surface of the discharge lamp can be sufficiently suppressed.

In addition to the configuration of the first aspect of the invention, the second invention of the present invention has a discharge port for discharging the gas on the shielding body.

Therefore, by discharging the clean flow of the layered gas formed along the surface of the discharge lamp from the discharge port, generation of the vortex shape can be suppressed, particularly in the vertical direction of the spiral flow which is rolled up toward the discharge lamp. .

Thereby, it is possible to suppress the incorporation of impurities into the flow of the gas, and it is possible to suppress the adhesion of the white powder to the discharge lamp.

More preferably, the above-mentioned air outlets are disposed on the ultraviolet irradiation devices on both sides of the discharge lamp. This is because the cooling effect and the adhesion suppressing effect of the white powder can be substantially uniformly increased in both side regions in the longitudinal direction of the discharge lamp. Even if the gas ejected in the case of the blown outlet is collided on the lower side of the discharge lamp, the cooling effect and the adhesion suppressing effect of the white powder can be sufficiently obtained as a whole of the discharge lamp. Further, it is preferable to form a leak path of the gas in the following cases. In other words, when the conveyance mechanism of the object to be irradiated such as a glass substrate is conveyed in one direction perpendicular to the longitudinal direction of the lamp, the gas leaks in one direction by the flow of the object to be irradiated.

In addition to the configuration of the first invention or the second invention, the discharge lamp is formed into a flat shape that is long in one direction and has a smoothly curved end portion in the short-side direction, and the air outlet is A plurality of the discharge lamps are arranged side by side, and the gas is discharged toward the end portion in the short-side direction of the discharge lamp.

In other words, the gas ejected from the end of the outlet toward the short side of the discharge lamp flows along the smooth curved shape of the end portion and gradually diffuses on the flat surface to form a layered flow.

As described above, since the flow of the gas is slowly diffused on the flat surface of the discharge lamp, generation of eddy due to the flow of the gas can be further suppressed.

According to a fourth aspect of the present invention, in addition to the configuration of the third aspect of the invention, the air outlets disposed on both sides of the discharge lamp are on the one side of the air outlet and the other side of the air outlet in the longitudinal direction of the discharge lamp. Arranged in a state of being shifted from each other.

In other words, the flow of the gas ejected from the air outlet is gradually diffused on the flat surface of the discharge lamp to suppress the occurrence of the whirling flow. However, in the configuration in which the gas ejected from both sides of the discharge lamp collides on the flat surface, A vortex flow may occur depending on the flow rate of the gas.

Therefore, by arranging the arrangement of the gas outlets on both sides of the discharge lamp, the collision of the gas on the flat surface of the discharge lamp is suppressed, and the occurrence of the vortex is more reliably eliminated, particularly toward the discharge lamp. The creation of a vortex flow in the vertical direction.

[Effect of the invention]

According to the first aspect of the invention, by appropriately setting the flow of the gas, the temperature rise of the discharge lamp or the adhesion of the white powder to the discharge lamp can be suppressed, and the management load of the ultraviolet irradiation device can be reduced as much as possible. The object to be treated is irradiated with ultraviolet rays.

Further, according to the second aspect of the invention, the occurrence of the vortex in the flow of the gas is suppressed, and in particular, the occurrence of the vortex flow in the vertical direction wound up above the discharge lamp is suppressed, so that the adhesion of the white powder to the discharge lamp can be further suppressed. .

Further, according to the third aspect of the invention, the generation of the vortex due to the flow of the gas is further suppressed, so that the adhesion of the white powder to the discharge lamp can be further suppressed.

Further, according to the fourth aspect of the invention, since the occurrence of the swirling flow of the gas can be surely eliminated, the adhesion of the white powder to the discharge lamp can be further suppressed.

The above described features and advantages of the present invention will be more apparent from the following description.

Hereinafter, an embodiment in which the ultraviolet irradiation device of the present invention is applied to a glass substrate cleaning device using an excimer lamp will be described with reference to the drawings.

The cleaning device CL is a device that irradiates the glass substrate 1 as a processing target of the cleaning process with vacuum ultraviolet rays of 200 nm or less (specifically, ultraviolet rays having a wavelength of 172 nm), whereby the ultraviolet rays and the ultraviolet rays are used. The cleaning action of the active oxygen decomposes to remove organic contaminants on the surface of the glass substrate 1. As shown in the schematic cross-sectional view of FIG. 4, in the housing 2, a roller 3 for transporting the glass substrate 1 is arranged, and a position along the center of the transport path of the transport roller 3 is along the glass substrate 1. In the transport direction (the direction indicated by the arrow TD in FIG. 4, and also in FIGS. 1 to 3), a plurality of discharge lamps 4 called so-called excimer lamps are arranged in line. As described above, the cleaning device CL is not provided with a glass window or the like between the lower surface of the irradiation surface of the discharge lamp (especially the flat discharge lamp having a flat surface on the lower surface) and the non-transported material such as the glass substrate. It consists of a gas device, and the arrangement space of the discharge lamp is open to the space outside the device. Such an ultraviolet irradiation device is referred to as a semi-open ultraviolet irradiation device.

In the cleaning device CL, when the glass substrate 1 is carried from the inlet of the upstream side (the right side in FIG. 4), the glass substrate 1 is transported to the downstream side at a set speed by the transport roller 3, and the discharge lamp 4 illuminates the glass substrate 1. Ultraviolet light.

Since the vacuum ultraviolet rays such as the 172 nm band irradiated by the discharge lamp 4 are largely absorbed by the oxygen in the air, the environment in the vicinity of the transport path of the glass substrate 1 in the casing 2 is replaced by a clean inert gas supplied from the outside. The inert gas passing through the above-described transfer path is discharged from the exhaust port 2a at the lower portion of the casing 2.

Further, in the present embodiment, nitrogen gas is used as the inert gas, but other inert gas may be used. Further, depending on the purpose, a small amount of air or oxygen or the like which can be substantially treated by irradiation with ultraviolet rays may be mixed with an inert gas (referred to as "process gas"). Further, a gas obtained by mixing two or more gases may be used.

FIG. 1 showing the discharge lamp 4 cut in the conveyance direction of the glass substrate 1 in a perspective view, FIG. 2 showing the discharge lamp 4 cut in the conveyance direction of the glass substrate 1 in the conveyance width direction view, and FIG. As shown in FIG. 3 in which the discharge lamp 4 cut in the horizontal direction slightly above the upper surface of the discharge lamp 4 is shown in a plan view, the discharge lamp 4 exemplified in the present embodiment has the transport width in one direction (the transport width of the glass substrate 1). The direction is a long flat shape, and both ends of the elongated flat tube are closed in the longitudinal direction.

More specifically, the discharge lamp 4 has an elongated rectangular shape in the one direction (the horizontal width direction of the glass substrate 1) in the normal direction view of the flat surface, and the short side direction of the flat surface (glass substrate 1) The end portion (side end portion) of the conveyance direction has a smoothly curved shape which is convexly curved outward.

The discharge lamp 4 is made of synthetic quartz glass, and a rare gas such as xenon, argon or krypton is sealed in the discharge lamp 4, and a halogen gas such as fluorine or chlorine is sealed as needed. )Wait.

Although not shown in the drawings, a pair of electrodes are formed on the upper surface side and the lower surface side (the side where the glass substrate 1 is present) on the flat surface of the discharge lamp 4.

The electrode on the upper surface side is a solid electrode in which a metal film electrode is formed in the same manner, and the electrode on the lower surface side is a mesh electrode in which a metal film is formed in a mesh shape.

When an alternating high voltage is applied to the pair of upper and lower electrodes, a so-called dielectric barrier discharge occurs in the internal space of the discharge lamp 4 and acts on the enclosed gas in the discharge lamp 4, in the case where the enclosed gas is helium. , the above-mentioned ultraviolet rays of the 172 nm band are generated. The generated ultraviolet rays are radiated to the outside through the gap of the mesh electrode on the lower surface side.

Since the discharge lamp 4 is provided with a flat surface that radiates the ultraviolet rays along the conveyance direction of the glass substrate 1, the glass substrate 1 to be conveyed can be irradiated with ultraviolet rays of uniform intensity over a relatively long distance.

Next, a gas supply mechanism GS that supplies nitrogen gas to the vicinity of the discharge lamp 4 will be described.

As shown in FIGS. 1 and 2, the nitrogen supply path of the gas supply means GS in the vicinity of the discharge lamp 4 is composed of a circular tube 11, a square tube 12 connected to the lower end of the round tube 11, and a glass substrate 1. The opposite side (i.e., the upper side) of the existing side is formed by the shielding body 13 covering the surrounding space of the discharge lamp 4.

A plurality of round pipes 11 are connected to one square pipe 12, and the round pipes 11 feed clean nitrogen gas supplied from the outside into the inner space of the square pipe 12.

The square tube 12 has substantially the same length as the discharge lamp 4 in the transport lateral direction of the glass substrate 1, and a plurality of openings 12a through which nitrogen gas is ejected are formed on both side faces of the square tube 12. These openings 12a are in principle arranged in an equidistant pitch in the longitudinal direction of the square tube 12.

The members connecting the circular tube 11 and the square tube 12 are disposed between the respective discharge lamps 4 arranged in the transport direction of the glass substrate 1, and the details will be described later, and each of the square tubes 12 is sprayed with nitrogen gas toward the discharge lamps 4 located on both sides thereof. .

In the conveyance lateral direction view of the glass substrate 1, the shielding body 13 has a substantially U-shaped cross section, and covers the vicinity of the discharge lamp 4 from above in a posture in which the open side of the "U" is directed downward. The lower end position of the shielding body 13 is located slightly below the lower end position of the square tube 12, and the shielding body 13 blocks the ultraviolet rays radiated from the side end portion of the discharge lamp 4 toward the square tube 12 side.

The shielding body 13 also has substantially the same length as the discharge lamp 4 in the conveyance lateral direction of the glass substrate 1.

The side surface of the square pipe 12 is disposed close to the vertical wall portion 13a of the shielding body 13 with a slight gap therebetween. In the vertical wall portion 13a, the air outlet 13b having a diameter slightly larger than the opening 12a of the square tube 12 is formed corresponding to each of the openings 12a, and the air outlet 13b is concentric with the opening 12a in the transport direction view of the glass substrate 1.

The height of the opening 12a and the outlet 13b coincides with the center position of the discharge lamp 4 in the height direction (i.e., the thickness direction), and the nitrogen gas supplied into the internal space of the square pipe 12 passes through the opening 12a and the outlet 13b toward the discharge lamp 4 side end. The top of the spout.

The discharge lamp 4 covered by the shielding body 13 on the upper side is attached to a central position at an equal distance from the air outlets 13b on both sides by a support member (not shown).

A slit-shaped discharge port 13c that discharges nitrogen gas is formed on the upper surface of the shielding body 13.

The discharge port 13c is located directly above the center position of the discharge lamp 4 in the conveyance direction of the glass substrate 1 (the short-side direction of the discharge lamp 4), and is arranged in the longitudinal direction of the discharge lamp 4 as indicated by a broken line in FIG. There are a plurality of states formed.

In the discharge lamp 4, the nitrogen gas is ejected from the air outlets 13b located on both the upstream side and the downstream side (more specifically, the sides of the upstream side and the downstream side) on the upstream side and the downstream side in the transport direction of the glass substrate 1. However, as shown in the plan view of Fig. 3, the arrangement of the nitrogen gas at the discharge position indicated by the arrow A is such that the arrangement of the air outlets 13b arranged at equal intervals on the upstream side and the downstream side is shifted by 1/2 pitch and arranged in a zigzag arrangement.

However, only the end portions of the array of the outlets 13b are disposed in a state in which the upstream side and the downstream side face each other.

In the arrangement configuration as described above, when the clean nitrogen gas sucked from the outside is supplied to the internal space of the square pipe 12 through the round pipe 11, the discharge 12a of the square pipe 12 and the air outlet 13b of the shielding body 13 are directed toward the discharge lamp. The side end portion of the curved shape of 4 was sprayed with nitrogen gas.

The nitrogen gas which is sprayed to the side end portion of the discharge lamp 4 is divided toward the upper surface side and the lower side of the discharge lamp 4 along the curved shape of the side end portion of the discharge lamp 4 as indicated by an arrow B in the flow direction of the nitrogen gas. The surface sides further flow along the upper and lower flat surfaces of the discharge lamp 4, respectively. By such a flow along the surface of the discharge lamp 4, a clean nitrogen gas layer is formed on the surface of the discharge lamp 4.

The nitrogen gas flowing along the flat surface on the upper surface side of the discharge lamp 4 flows further toward the discharge port 13c and is discharged to the outside.

By forming the nitrogen gas of the flow path as described above, it is needless to say that the space between the lower surface side of the discharge lamp 4 and the glass substrate 1 is reliably replaced by nitrogen gas, and the discharge lamp 4 also has a relatively small flow rate of nitrogen gas. Effective cooling is achieved, and the adhesion of white powder is effectively suppressed by the flow of clean nitrogen. Further, by discharging the nitrogen gas flowing on the upper side through the discharge port 13c, it is possible to suppress the disturbance of the airflow which causes the white powder to scatter. The nitrogen gas flowing on the lower side is discharged from the exhaust port 2a at the lower portion of the casing 2, or flows in the TD direction together with the object to be processed.

[Other Embodiments]

Hereinafter, other embodiments of the present invention will be described.

(1) In the above embodiment, the discharge lamp 4 having a flat shape is exemplified. However, the present invention can also be applied to a discharge lamp having various shapes such as a circular cross section.

(2) In the above-described embodiment, the arrangement of the discharge port 13b on the upstream side in the transport direction of the glass substrate 1 and the blow-out port 13b on the downstream side in the transport lateral direction is arranged in a zigzag manner. The side air outlet 13b and the downstream side air outlet 13b may be disposed to be completely opposed to each other.

(3) In the above embodiment, the ultraviolet irradiation device of the present invention is applied to the cleaning device CL, but it may be applied to various treatment devices using ultraviolet rays.

(4) In the above-described embodiment, the configuration in which the gas is supplied to each of the discharge lamps 4 by the gas supply means GS is exemplified as a configuration in which the nitrogen gas is ejected from both sides of the one discharge lamp 4. The gas is supplied by uniformly discharging a gas to a plurality of arranged discharge lamps.

(5) In the above-described embodiment, the discharge port 13c is formed at a position above the discharge lamp 4 of the shield 13 (the position opposite to the side where the discharge lamp 4 is located on the side of the glass substrate 1). As shown in FIG. 5, it is possible to provide a configuration in which the discharge port 13c is not provided in the shielding body 13. Fig. 5 is a view corresponding to Fig. 2 in the above embodiment.

When the discharge port 13c is not provided in the shielding body 13, the nitrogen gas flowing along the upper surface of the discharge lamp 4 in FIG. 5 is temporarily raised, and the pressure between the adjacent air outlets 13b is lower. On the lower side of the discharge lamp 4 (the side where the glass substrate 1 is present with respect to the discharge lamp 4) is discharged.

Even in the case of the above configuration, the adhesion of the white powder to the discharge lamp 4 can be suppressed by the flow of the layered clean nitrogen gas formed on the surface of the discharge lamp 4.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the invention, and any one of ordinary skill in the art can make some modifications and refinements without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims.

1. . . glass substrate

2. . . framework

2a. . . exhaust vent

3. . . Transfer roller

4. . . Discharge lamp

11. . . Round tube

12. . . Square tube

12a. . . Opening

13. . . Screening body

13a. . . Vertical wall

13b. . . Blowout

13c. . . Discharge

A, B. . . arrow

CL. . . Cleaning device

GS. . . Gas supply mechanism

TD. . . direction

Fig. 1 is a perspective view of a main part of an embodiment of the present invention.

Fig. 2 is a side elevational view of the essential part of the embodiment of the present invention.

Fig. 3 is a plan view showing an injection position of an inert gas according to an embodiment of the present invention.

Fig. 4 is a schematic configuration diagram of an apparatus according to an embodiment of the present invention.

Fig. 5 is a side elevational view of the essential part of another embodiment of the present invention.

11. . . Round tube

12. . . Square tube

12a. . . Opening

13. . . Screening body

13a. . . Vertical wall

13b. . . Blowout

13c. . . Discharge

GS. . . Gas supply mechanism

TD. . . direction

Claims (5)

An ultraviolet irradiation device is provided with a discharge lamp that emits ultraviolet rays toward a processing target, and a gas supply mechanism that supplies a gas to a space between the discharge lamp and the processing target, wherein the gas supply mechanism includes a discharge lamp side The blowing outlet of the gas and the shielding body covering the space around the discharge lamp on the side opposite to the side where the object to be processed exists, wherein the gas is directly blown to the side of the discharge lamp Producing a gas flow along the upper surface and the lower surface of the discharge lamp described above. The ultraviolet irradiation device according to claim 1, wherein the shielding body is provided with a discharge port for discharging the gas. The ultraviolet irradiation device according to the first or second aspect of the invention, wherein the discharge lamp is formed in a flat shape that is long in one direction and has a smoothly curved shape at an end portion in a short side direction, and the air outlet is A plurality of the discharge lamps are arranged side by side, and the gas is discharged toward the end portion in the short-side direction of the discharge lamp. The ultraviolet irradiation device according to claim 3, wherein the air outlets disposed on both sides of the discharge lamp are on the one side of the air outlet and the other side of the air outlet in the longitudinal direction of the discharge lamp Arranged in a state of being shifted from each other. An ultraviolet irradiation device is provided with a discharge lamp that emits ultraviolet rays toward a processing target, and a gas supply mechanism that supplies a gas to a space between the discharge lamp and the processing target, wherein the gas supply mechanism includes a discharge lamp side The blowing outlet of the gas and the shielding body covering the space around the discharge lamp on the side opposite to the side where the object to be processed exists, wherein the shielding body is provided with a discharge port for discharging the gas.