JP2001217216A - Method and device for ultraviolet-ray irradiation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the running cost of an ultraviolet-ray irradiation device using an excimer lamp by reducing the consumption of an inert gas and cooling water necessary for operating the device. SOLUTION: A method for ultraviolet-ray irradiation includes a step of preparing a lamp device equipped with an excimer lamp 11 in a hermetically sealed enclosure 12 having a light transmitting window 13, a step of setting a work W in such a way that its surface to be worked is irradiated with ultraviolet rays from the lamp 11, and a step of filling up the enclosure 12 with an inert gas by introducing the inert gas into the enclosure 12 in parallel with the step of setting the work W. This method also includes a step of cleaning or reforming the work W by irradiating the work W with the ultraviolet rays in a state where the introduction of the inert gas is stopped, and a step of discharging the gas from the enclosure 12 after the cleaning or reforming of the work is completed. By repeating the these steps, a plurality of works is cleaned or reformed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for irradiating an ultraviolet ray for cleaning or modifying the surface of a substrate such as a semiconductor wafer or a glass substrate for liquid crystal, and more particularly, to a running cost for performing the cleaning or the modification. The present invention relates to a method and an apparatus for irradiating ultraviolet rays, which are suitable for reducing the amount of ultraviolet rays.

[0002]

2. Description of the Related Art As a method for cleaning the surface of a semiconductor wafer or a glass substrate for a liquid crystal display, a method using ultraviolet light is known. It is most common to use a low-pressure mercury lamp as the ultraviolet light source, and this uses the 185 nm and 254 nm bright lines of the low-pressure mercury lamp. When an atmosphere in which oxygen is present is irradiated with light emitted from a low-pressure mercury lamp, the oxygen molecules absorb the light and emit two oxygen atoms O ( ³
P). As can be seen from the fact that light having a wavelength of 200 nm or less is generally called vacuum ultraviolet light,
This is because oxygen has a strong absorption band for the light having a wavelength of 200 nm or less. Oxygen atoms generated in this process combine with undissociated oxygen molecules around them to form ozone (O
₃ ) is generated.

O ₂ + hν (185 nm) → O ( ³ P) + O ( ³ P) O ( ³ P) + O ₂ → O ₃

Further, a wavelength of 254 from a low-pressure mercury lamp is used.
The light in the vicinity of nm is strongly absorbed by ozone, and the ozone that receives the light is converted into oxygen molecules (O ₂ ) and active oxygen atoms O (
¹ Dissociate into D). O ₃ + hν (254 nm) → O ₂ + O ( ¹ D)

[0005] Ozone and active oxygen generated in these processes have the ability to oxidize contaminants adhering to the substrate surface.

[0006] Further, the ultraviolet light itself applied to the substrate also has a high energy and exceeds the binding energy of many organic compounds. For this reason, the contaminants on the substrate surface are irradiated with ultraviolet rays, whereby their chemical bonds are broken and further oxidized by the above-mentioned ozone or active oxygen.
Scattered from the substrate surface as a ₂ O) and carbon dioxide (CO _2),
Removed. The above cleaning method is known as UV ozone cleaning.

[0007] UV ozone cleaning removes organic contaminants and cannot remove inorganic and other contaminants.
Unlike wet cleaning methods that use chemicals, which were common cleaning methods up to that point, they do not use discharged chemicals, and their processing costs, equipment, and facilities are simple, so they have become widespread in LSI and liquid crystal display manufacturing processes. I have.

On the other hand, low-pressure mercury lamps have greatly contributed to the spread of the above-mentioned UV ozone cleaning method due to their characteristic bright lines. In recent years, however, excimer lamps have been known as light sources capable of more efficient UV ozone cleaning. To be able to
Replacement of conventional low-pressure mercury lamps as UV ozone cleaning light sources is in progress. Excimer lamps eliminate the disadvantages of low-pressure mercury lamps such as heat radiation to the substrate and lighting performance.Furthermore, because they have shorter emission lines, they excel in cutting organic compounds and produce more active oxygen. There is an advantage that it can be performed efficiently.

That is, since the low-pressure mercury lamp has a radiation spectrum in the infrared region other than 185 nm and 254 nm, there is a problem that the substrate temperature rises by irradiating the substrate with light. There are processes that dislike high temperatures in the manufacture of LSIs and liquid crystal displays.
Ozone cleaning could not be performed. Also, since the low-pressure mercury lamp takes several minutes to several tens of minutes after the start of lighting until the intensity of the emitted light stabilizes, it cannot be turned off during the process work. If necessary, it was necessary to provide a mechanical shutter made of a metal plate or the like in the irradiation device.

On the other hand, the emission line of the excimer lamp is almost single, and hardly emits infrared rays having a substrate heating effect. In addition, the lighting performance is excellent, the intensity of the emitted light is stabilized in several hundred milliseconds, and the light can be turned off in the same time. Therefore, unlike a low-pressure mercury lamp, it can be turned on when necessary and turned off when not needed.

As shown in FIG. 5, an excimer lamp 50 is
Xenon gas 52 is sealed in a double tube 51 made of quartz glass, and a high voltage of 7 to 10 kV is applied at a frequency of 100 to 500 kHz between an inner electrode 53 and an outer electrode 54 provided in the tube. You. Quartz glass, which is a dielectric to which a high voltage is applied, generates a micro-discharge by dielectric barrier discharge (silent discharge), and uses the energy to excite and combine the xenon gas enclosed inside, and the excited gas In the process of returning molecules to the ground state, they emit light having a wavelength specific to gas. The emission light of the excimer lamp filled with xenon gas has a wavelength of 172 nm as its center and a half-width of about 14 nm.

Certain excimer lamps 50 have cooling water 55 introduced as a coolant at the center thereof. This is to prevent the quartz glass from being damaged and the radiation light intensity from being reduced due to the increase in the lamp temperature. In addition, by cooling the inside of the lamp with a refrigerant, it becomes possible to apply a larger electric power than that of an air-cooled lamp, and thus it is possible to obtain high-output ultraviolet light. Generally, pure water having a specific resistance of 0.5 MΩ · cm or more is used as the cooling water 55 in order to avoid the risk of current leakage to the inner electrode 53.

The wavelength 172 emitted from the excimer lamp
The light of nm is more strongly absorbed by oxygen molecules than 185 nm, which is the emission line of a low-pressure mercury lamp. Oxygen molecule has a wavelength of 175n
m or less, the excited active oxygen O (
¹ D) is generated. O ₂ + hν (172 nm) → O ( ¹ D) + O ( ³ D)

[0014] For this reason, active oxygen is generated more efficiently than when a low-pressure mercury lamp is used, and ultraviolet rays having a shorter wavelength of 172 nm are excellent in breaking chemical bonds of contaminants. I can do it.

On the other hand, the light of 172 nm is excellent in generating active oxygen, but has a large absorption by oxygen. Therefore, in UV ozone cleaning, it is necessary to provide a large distance between the light emitting surface and the surface of the substrate to be irradiated with ultraviolet rays. Can not. Therefore, in practice, the distance between the light emitting surface and the substrate surface needs to be close to about 2 to 5 mm. As shown in FIG. 6, when the shape of the excimer lamp 50 is tubular, the portion located at the center of the lamp has a short distance to the surface of the substrate W, and the portion at the lamp end has a long distance to the substrate W. This problem can be reduced by increasing the distance between the excimer lamp 50 and the substrate W, but the light having a wavelength of 172 nm, which is the radiation light of the excimer lamp, is strongly absorbed by oxygen molecules as described above. Therefore, it is necessary to provide an optical path for the ultraviolet rays from the excimer lamp to reach the substrate in an atmosphere in which oxygen molecules do not exist as much as possible. Further, since the excimer lamp itself is also exposed to the oxidizing atmosphere, there is a problem that the outer electrode 54 shown in FIG. 5 is corroded.

As a method for solving such a problem, a conventional ultraviolet irradiation apparatus using an excimer lamp employs a configuration as shown in FIG. That is,
The excimer lamp 50 is connected to the gas inlet 71 and the gas outlet 7
2 is radiated with ultraviolet rays while an inert gas such as nitrogen is constantly flowed into the case 70 through the gas inlet 71 and the gas outlet 72. The ultraviolet light emitted from the excimer lamp 50 is applied to the substrate W through an ultraviolet light transmitting window 73 such as a synthetic quartz glass provided in the case 70. It should be noted that cooling water is constantly flowing in the center of the excimer lamp 50 during operation of the ultraviolet irradiation device.

[0017]

However, in the above-mentioned conventional ultraviolet irradiation apparatus, the running cost in its operation is a major problem. In recent years, in the production of LSIs, liquid crystal displays, and the like, reduction of the production cost and reduction of emission materials, so-called zero emission, are major issues. In an ultraviolet irradiation apparatus using an excimer lamp, reduction of consumption of the above-mentioned inert gas and cooling water required for its operation is strongly demanded from the market.

However, in the conventional ultraviolet irradiation apparatus, the inert gas is supplied to the excimer lamp 50 as described above.
Is continuously supplied from the gas inlet 71 at a predetermined flow rate (for example, several liters / minute) in order to replace the air containing oxygen into the case 70 in which the air is supplied, and is discharged from the gas outlet 72 as it is. Further, as described above, the cooling water is also constantly flowing during the operation of the ultraviolet irradiation device.

As a result, when a large number of substrates are continuously processed, a large amount of inert gas and expensive cooling water such as ultrapure water are required, which raises the running cost of the apparatus.

Accordingly, it is an object of the present invention to reduce the running cost of the ultraviolet irradiation apparatus using these excimer lamps by reducing the consumption of inert gas and cooling water required for the operation.

[0021]

According to the present invention, there is provided an ultraviolet irradiation method for irradiating an ultraviolet ray to a surface to be processed of a workpiece to clean or modify the surface. Is provided. That is, the method of the present invention
(A) preparing a light source that emits ultraviolet light having a wavelength of 175 nm or less, preferably a lamp device having an excimer lamp, in a closed casing having a light transmitting window; and (b) transmitting the light through the light transmitting window and closing the lamp. Installing the workpiece so that ultraviolet light from the light source reaching the outside of the housing is radiated to the processing surface; and (c) installing the workpiece in the closed housing in parallel with the step of installing the workpiece. A step of introducing an inert gas into the casing and filling the inside of the casing with the inert gas; and (d) turning on the light source and stopping the introduction of the inert gas into the closed casing. A step of irradiating ultraviolet rays to the surface to be processed of the object to clean or modify the surface; and (e) a step of exhausting the gas in the closed casing after the cleaning or modification of the surface to be processed is completed. And by repeating the above steps (b) to (e), Cleaning or modifying the number of the workpiece.

In the step (d), the introduction of the inert gas into the closed casing is preferably stopped based on a timing at which the light source is turned on. More preferably, the inert gas is provided in the closed casing. This is performed by closing the valve at the inlet of the inert gas.

In the step (e), the discharge of the gas is preferably performed based on the timing of turning off the light source, and more preferably, the discharge of the inert gas provided in the closed casing. This is done by opening a closed valve at the outlet.

Further, in the present invention, it is preferable that the start of the gas discharge in the step (e) is performed substantially simultaneously with the start of the introduction of the inert gas in the step (c).

The present invention also provides a step of supplying a coolant for cooling the light source to the vicinity of the light source in parallel with the step (d), and a step of supplying the refrigerant in parallel with the step (e). And a step of stopping.

In parallel with the step (c), the cooling medium for cooling the light source is supplied at a first supply amount per unit time.
Supplying the refrigerant to the vicinity of the light source; and, in parallel with the step (d), setting the supply amount of the refrigerant to a second supply amount larger than the first supply amount; ), A step of returning the supply amount of the refrigerant from the second supply amount to the first supply amount.

Further, the step (d) is preferably performed while moving the workpiece so that the surface to be processed passes an ultraviolet radiation region of the light source.

According to the present invention, instead of the steps (c) to (e), an inert gas is supplied into the closed casing per unit time in parallel with the step (c) of installing the workpiece. A step of flowing at a first flow rate; and (d) turning on the light source and reducing a flow rate of the inert gas flowing into the closed casing per unit time to a second flow rate smaller than the first flow rate. A step of irradiating ultraviolet rays to the processing surface of the workpiece and cleaning or modifying the processing surface in a state where the flow rate is reduced; and (e) after cleaning or modifying the processing surface, Returning the flow rate of the inert gas flowing into the closed casing from the second flow rate to the first flow rate.

In this case, as one aspect, the decrease in the flow rate of the inert gas into the closed casing in the step (d) is performed based on a change in the pressure in the closed casing.

According to the present invention, there is further provided an ultraviolet irradiation method for irradiating an ultraviolet ray to a surface to be processed of a workpiece to clean or modify the surface. A step of preparing a lamp device having a light source that emits ultraviolet light of 175 nm or less; and (b) ultraviolet light from the light source that passes through the light transmitting window and reaches outside the closed casing is emitted to the surface to be processed. As described above, a step of sequentially passing the plurality of workpieces under the ultraviolet radiation region,
(C) In parallel with the step of passing the plurality of workpieces under the ultraviolet radiation region, introducing an inert gas into the closed casing and filling the inside with the inert gas,
Repeating the step of stopping the introduction of the inert gas, thereby cleaning or reforming a plurality of workpieces.

The present invention also relates to an ultraviolet irradiation device for irradiating an ultraviolet ray to a surface to be processed of a workpiece to clean or modify the surface. An ultraviolet irradiation apparatus according to the present invention includes a lamp device having a light source that emits ultraviolet light having a wavelength of 175 nm or less, preferably an excimer lamp, and a sealed device that transmits through the light transmission window. A base on which the workpiece is installed so that ultraviolet light from the light source reaching the outside of the body is radiated to the surface to be processed, and inert gas introduction means for introducing an inert gas into the closed casing. Control means for illuminating the light source and irradiating ultraviolet rays to the surface to be processed of the workpiece to perform cleaning or reforming thereof, thereby preventing an inert gas from flowing into the closed casing. It is configured with.

In this case, it is preferable that the control means prohibits the flow of the inert gas into the closed casing based on the timing of turning on the light source.

In a preferred embodiment, an inflow valve for closing an inflow port of the inert gas provided in the closed casing is further provided, and the opening and closing of the inflow valve is preferably controlled by the control means. .

It is preferable that the control means is configured to discharge gas from the closed casing based on a timing of turning off the light source.

In a preferred embodiment, the apparatus further comprises pressure change detecting means for detecting a change in pressure in the closed casing, and the control means opens and closes the inflow valve based on the detected change in pressure. It can be configured to control.

Further, in another embodiment, there is provided an oxygen concentration detecting means for detecting the oxygen concentration in the closed casing,
The control means may be configured to control the opening and closing of the inflow valve based on the detected change in the oxygen concentration.

Further, in another embodiment, the apparatus further comprises a discharge valve for closing a discharge port of the inert gas provided in the closed casing, and the opening and closing of the discharge valve is controlled by the control means. Can be.

In a preferred embodiment, the control means includes:
The start of the discharge of the gas is performed substantially simultaneously with the start of the introduction of the inert gas.

In another aspect of the present invention, a coolant supply means for supplying a coolant for cooling the light source to the vicinity of the light source, and illuminating the light source to emit ultraviolet rays to the surface of the workpiece to be processed. Control means for stopping the supply of the refrigerant or reducing the supply amount except during the time of performing the washing or the reforming is further provided.

In this case, the coolant supplied by the coolant supply means is preferably water, and more preferably pure water having a specific resistance of 0.5 MΩ · cm or more.

Further, the refrigerant supply means includes a circulation path for circulating the refrigerant in the vicinity of the light source, a pump for circulating the refrigerant in the circulation path, and a cooling means for cooling the refrigerant. A filter for removing impurities in the refrigerant.

Further, the ultraviolet irradiation apparatus of the present invention may further comprise a moving means for moving the workpiece so that the surface to be processed passes through an ultraviolet radiation region of the light source.

According to the present invention, there is also provided an ultraviolet irradiation apparatus for irradiating an ultraviolet ray to a surface to be processed of a workpiece to clean or modify the surface of the workpiece.
A lamp device having a light source that emits ultraviolet light having a wavelength of 175 nm or less, and a plurality of the above-described light-emitting devices that emit ultraviolet light from the light source that passes through the light-transmitting window and reaches outside the closed casing to the surface to be processed. Moving means for sequentially passing the workpiece under the ultraviolet radiation region; inert gas introducing means for introducing an inert gas into the closed casing; and the plurality of workpieces emitting the ultraviolet light. Control means for repeatedly introducing an inert gas into the closed casing and filling the casing with the inert gas while sequentially passing under the region, and stopping the introduction of the inert gas. Can be configured.

[0044]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on one embodiment shown in the drawings. Hereinafter, the present invention will be described by taking an example of an ultraviolet irradiation apparatus that irradiates an ultraviolet ray to a glass substrate for a liquid crystal as a workpiece to remove organic contaminants on the surface. FIG. 1 is a front view showing a schematic configuration of an ultraviolet irradiation device according to the present invention. As shown in the drawing, the ultraviolet irradiation apparatus 10 of the present invention has a lamp house 12 having an excimer lamp 11 inside. The excimer lamp 11 installed in the lamp house 12 has a substantially cylindrical outer shape, and emits ultraviolet rays from the circumferential surface. In one embodiment, the fill gas in the lamp tube is xenon and 172n
m ultraviolet rays. However, in the present invention,
Other filling gases such as neon fluoride (108
nm), argon (126 nm), krypton (146)
nm), fluorine (154 nm), argon chloride (175 n
m) or the like may be used. The excimer lamp 11 can be excited by any one of a dielectric barrier discharge, a high-frequency discharge, a microwave, and an electron beam.

The dielectric excimer lamp used in the present embodiment is of a water-cooled type, which is equivalent to the one shown in FIG. Cooling water is circulated into the center of the double pipe by a cooling water circulating device described later.

A light transmitting member 13 is provided on the lower surface of the lamp house 12 as a light extraction window. Ultraviolet rays radiated from the excimer lamp 11 pass through the light transmitting member 13 and irradiate the workpiece W. Is done. As the light transmitting member 13, it is preferable to use water-containing synthetic quartz glass having excellent light transmittance in a wide wavelength range. The lamp house 12 further includes a reflection mirror 14 made of, for example, aluminum. The reflection mirror 14 covers the upper part and the side part of the excimer lamp 11 and lowers the light radiated above and to the side of the excimer lamp 11, that is, the workpiece W
Collect light toward.

The lamp house 12 is a closed container, and the inside thereof is filled with an inert gas. As a result, the extent to which the ultraviolet light from the excimer lamp 11 is attenuated in the lamp house 12 is suppressed. As the inert gas, nitrogen, argon, helium gas, or the like, which hardly absorbs light, can be used. In view of the cost, nitrogen gas is preferably used.

In the present invention, the ultraviolet irradiation device 10 has a mechanism for introducing the inert gas into the lamp house 12 and introducing the inert gas discharged from the lamp house 12. The lamp house 12 has a gas inlet 15 for introducing an inert gas, and a gas outlet 16 for discharging the inert gas. The inert gas introduction mechanism includes a gas supply source 17 such as a gas cylinder, and a mass flow controller 1 for controlling a flow rate of the supplied inert gas.
8. Inlet solenoid valve 1 provided on the gas inlet 15 side
9 and an outlet solenoid valve 20 provided on the gas outlet 16 side. The flow rate of the inert gas from the gas supply source 17 is controlled by the mass flow controller 18, and is guided into the lamp house 12 from the gas inlet 15.

The inlet solenoid valve 19 allows or prohibits the introduction of the inert gas into the lamp house 12 by opening and closing. The outlet solenoid valve 20 allows or prohibits the discharge of the gas in the lamp house 12 by opening and closing. As will be described later, the ultraviolet irradiation apparatus 10 of the present invention basically does not introduce an inert gas during the cleaning or reforming of the workpiece W, but does so before and after. The opening and closing of the inlet solenoid valve 19 and the outlet solenoid valve 20 is controlled by a control signal output from a control unit 22 described later. Double solenoid valve 19
The timing of opening and closing of and 20 will be described later.

The ultraviolet irradiation device 10 is further provided with a power supply unit 21 of the excimer lamp 11 and a control unit 22 thereof. The excimer lamp 11 is turned on by the electric power supplied from the power supply unit 21, thereby realizing the emission of the ultraviolet light to the workpiece W. The control unit 22 transmits a control signal for controlling on / off of the excimer lamp 11 to the power supply unit 2.
Output to 1. The power supply unit 21 receives a control signal for turning on or off from the control unit 22 and
The power supply to 1 is turned on or off, and this is turned on or off. The excimer lamp 11 is turned on or off several hundred milliseconds after the control signal is given by the control unit 22. To turn on the excimer lamp 11,
The power supply unit 21 converts a high voltage of 1 kV to 10 kV to 50 kHz.
A voltage of between 300 and 300 kHz is applied between the electrodes.

The control unit 22 controls the excimer lamp 1
In addition to the control of the power supply unit 21, the opening and closing of the inlet solenoid valve 19 and the outlet solenoid valve 20 is controlled. The control unit 22
A control signal (for example, a signal of 0 V, hereinafter referred to as a close signal) for closing the valve is output to the inlet solenoid valve 19 at a timing when a lamp lighting signal is output to the power supply unit 21. A control signal (for example, a signal of +24 V; hereinafter, an open signal) for opening the valve is output at a timing at which the light-off signal is output to 21. As a result, the inlet solenoid valve 19 is closed during the lighting period of the excimer lamp 11, that is, the cleaning period of the workpiece W, and the inflow of the inert gas is stopped. The discharge and installation period of the work W is opened,
During this time, the inflow of the inert gas into the lamp house 12 is permitted.

Further, the control unit 22 controls the discharge solenoid valve 2.
For 0, the above-mentioned close signal and open signal are output at the same timing. As a result, the outlet solenoid valve 20 is also closed during the lighting period of the excimer lamp 11 and the inert gas in the lamp house 12 is maintained, while being opened during the lighting period of the excimer lamp 11. Accordingly, the gas in the lamp house 12 including the inert gas can be discharged to the outside.

The ultraviolet irradiation device 10 is further provided with a cooling water circulation device 30 used for cooling the excimer lamp 11. The cooling water circulating device 30 is a device for circulating the cooling water maintained at a predetermined temperature in the double tube of the excimer lamp 11, and the cooling water provided by this device is supplied from the supply path 34 to the inside of the lamp house 12. Excimer lamp 11
And is discharged from the discharge passage 35 and returned into the cooling water circulation device 30. By circulating the cooling water, the irradiation light amount of the excimer lamp is improved. Cooling water circulation device 30
The specific configuration will be described later.

On the cooling water supply path 34, a flow path solenoid valve 36 for opening and closing the flow path is provided. Flow path solenoid valve 3
6 permits or prohibits the introduction of the cooling water into the excimer lamp 11 by opening and closing. As will be described later, the ultraviolet irradiation apparatus 10 of the present invention basically performs cleaning or modification of the workpiece W, that is, the excimer lamp 1.
The cooling water is introduced only during the lighting of 1, and before and after the cooling water is stopped. This is excimer lamp 1
1 emits heat due to its lighting, so that cooling is required during that time, while there is no problem of heat generation while the excimer lamp 11 is off, so that it is stopped to suppress the consumption of cooling water. The opening and closing of the flow path electromagnetic valve 36 is controlled by a control signal output from the control unit 22 in the same manner as the above-described inlet electromagnetic valve 19 and outlet electromagnetic valve 20. On the other hand, the control is performed by the negative logic, which is opposite to that of the inlet solenoid valve 19 and the outlet solenoid valve 20. That is, when the closing signal is output from the control unit 22 at the time of turning on the lamp, the flow path solenoid valve 36 is opened, whereby the inflow of cooling water becomes possible, and the control is performed at the time of turning off the lamp. When the open signal is output from the unit 22,
The flow path solenoid valve 36 is closed, thereby stopping the flow of the cooling water. By controlling the flow path solenoid valve 36,
The cooling water can be circulated only during the lighting period of the excimer lamp 11. In the present embodiment, an electromagnetic valve is not provided on the cooling water discharge passage 35, but may be provided.

The ultraviolet irradiation device 10 further includes a transfer device 23 for placing and fixing the workpiece W so as to be transportable below the lamp house 12. The transport device 23 is a mechanism that transports a rectangular workpiece W such as a glass substrate in the horizontal direction, and passes through the irradiation range of the ultraviolet light from the excimer lamp 11. The transfer device 23 includes a mounting table 24 on which the workpiece is stably mounted, and which is moved together with the workpiece. The height position of the mounting table is such that the distance between the upper surface of the workpiece W mounted thereon, ie, the workpiece surface and the bottom of the lamp house 12, ie, the light transmitting member 13, is 10 mm or less, preferably 5 mm or less.
It is set to be in the range of ２2 mm. It will be apparent to those skilled in the art that by shortening the distance between the lamp device and the work surface, the efficiency of cleaning or reforming is improved. The transport device 23 is controlled by a signal from a transport control unit (not shown) synchronized with the timing of turning on and off the excimer lamp 11. In realizing the present invention, it is not essential that the workpiece W be transported by the transport device 23. When the workpiece W has a relatively small circular shape like a semiconductor wafer, an apparatus having a mechanism for rotating the excimer lamp 11 with respect to the excimer lamp 11, for example, a turntable may be provided. When the entire surface of the workpiece can be irradiated with ultraviolet rays (for example, a plurality of excimer lamps are arranged in parallel), such a mechanism for moving the workpiece is not provided. What you support is fine.

Although not shown in the drawing, it is preferable that at least the mounting table 24 and the workpiece W mounted thereon are disposed in a closed processing chamber. This is to prevent the ozone gas and the like generated by the irradiation of the workpiece W with ultraviolet rays from leaking to the outside and to ensure the safety thereof. In addition, a gas inlet into the processing chamber is provided, and a wall of the processing chamber is covered with a fluorine resin material such as a Teflon (registered trademark) sheet, so that a corrosive gas such as a chlorine gas or a fluorine gas containing no oxygen fluid is provided. May be filled in the processing chamber.

Next, FIG. 2 shows a schematic configuration of the cooling water circulation device 30. As shown in the figure, a cooling water circulation device 30 includes an impurity removal filter 31 and a cooler 32.
And a liquid feed pump 33, and is installed in a circulation path including the supply path 34, the excimer lamp 11, and the discharge path 35. The cooling water is circulated in this circulation path at a rate of, for example, 5 liters per minute by the liquid feed pump 33. The impurities in the cooling water are removed by the impurity removal filter 31, and the water temperature raised by the heat of the excimer lamp 11 is recooled by the cooler 32. The cooling water (pure water having a specific resistance of 0.5 MΩ · cm or more in the embodiment) in the cooling water circulation device 30 needs to be periodically replaced. be able to.

Next, the procedure of cleaning the workpiece W by the ultraviolet irradiation device 10 will be described. Here, a description will be given along a case where a large number of workpieces W are sequentially installed in the ultraviolet irradiation device 10 and processed. In explaining, FIG.
Please refer to FIG. FIG. 3 is a flowchart showing a cleaning procedure by the present ultraviolet irradiation apparatus. When the main power supply of the ultraviolet irradiation device is turned on in step 301 shown in FIG.
The initialization is started. In the initial setting, regarding the introduction of the inert gas, the inlet solenoid valve 19 and the outlet solenoid valve 20
Is opened, whereby an inert gas from the gas supply source 17 is introduced into the lamp house 12. Further, with respect to the circulation of the cooling water, the cooling water circulating device 30 is started, but the flow path solenoid valve 36 is closed, whereby the excimer lamp 1 is closed.
The introduction of new cooling water into 1 is stopped.

Next, in step 302, the workpiece W, which is a glass substrate, is mounted on the mounting table 24. The workpiece W is
It is taken out of the substrate stocker by a transfer robot (not shown) and placed on the mounting table 24. When it is confirmed by the detection means such as the optical sensor that the workpiece W is placed on the mounting table 24, the control unit 22 outputs a lamp lighting signal and a solenoid valve closing signal (Step 303). Upon receiving the lamp lighting signal, the power supply unit 21 supplies power to the excimer lamp 11 to light it. In addition, the inlet solenoid valve 19 and the outlet solenoid valve 20 are closed in response to the above-mentioned closing signal, thereby introducing an inert gas into the lamp house 12 and containing an inert gas from the lamp house. Gas emission is stopped. At the same time, the closing signal is given to the flow path solenoid valve 36 on the circulation path of the cooling water to open it (negative logic). Thereby, the cooling water circulation device 30
, The supply of the cooling water into the excimer lamp 11 is started.

At substantially the same time as the control signal from the control unit 22,
A drive signal is supplied to the transfer device 23, whereby the transfer of the workpiece W is started (Step 304). Workpiece W
As a result of the transfer, the light passes through the irradiation range of the ultraviolet light from the excimer lamp 11, whereby the surface to be processed is cleaned. During this time, the flow of the inert gas into the lamp house 12 is stopped. On the other hand, the supply of the cooling water to the excimer lamp 11 is continued.

When the entire area of the surface to be processed of the workpiece W has passed the irradiation range of the ultraviolet rays and the processing has been completed (step 30).
5), the control unit 22 outputs a lamp extinguishing signal and a solenoid valve opening signal (Step 306). Upon receiving the lamp extinguishing signal, the power supply unit 21 stops supplying power to the excimer lamp 11 and extinguishes it. Further, the inlet solenoid valve 19 and the outlet solenoid valve 20 are respectively opened in response to the above-mentioned opening signal, thereby introducing an inert gas into the lamp house 12 and containing an inert gas from the lamp house. Gas discharge is started. At the same time, the open signal is given to the flow path solenoid valve 36 on the circulation path of the cooling water to close it (negative logic). Thereby, the supply of the cooling water into the excimer lamp 11 by the cooling water circulation device 30 is stopped.

In step 307, the processed workpiece W is carried out by the transfer robot and returned to the substrate stocker. Then, the process is returned to the step 302, and the workpiece W to be processed next is carried into the apparatus and set therein. By the control of the solenoid valves, the inert gas is supplied to the lamp house 12 between the time when the workpiece is carried out and the time when the next workpiece is carried in.
Introduced within. On the other hand, during this time, the circulation of the cooling water is stopped. Step 3 for the newly loaded workpiece
Steps 03 to 306 are sequentially executed.

In one embodiment, the time until the workpiece is unloaded and the next workpiece is loaded (steps 307 to 302)
Is approximately 30 seconds. The moving speed of the workpiece by the transfer device 23 is 30 mm per second, and the length is 800 m.
Approximately 27 seconds (= 800 mm / 30 mm per second) was required to irradiate the entire region of the workpiece with the ultraviolet light. In this case, the flow of the inert gas is controlled by about 2
The cooling is stopped for 7 seconds, and the circulation of the cooling water is stopped for about 30 seconds.

Next, an ultraviolet irradiation apparatus according to another embodiment of the present invention will be described. FIG. 4 is a configuration diagram of an ultraviolet irradiation device according to another embodiment of the present invention. The ultraviolet irradiation apparatus according to the present embodiment is one in which a workpiece such as a glass substrate for liquid crystal is sequentially and continuously passed under ultraviolet irradiation to remove organic contaminants on the surface. As shown in the figure, the ultraviolet irradiation device 40 includes a transfer device 42 having a large number of transfer rollers 41 for continuously transferring the workpiece W. The workpiece W is sequentially transferred from one side (the left side in the illustrated example) of the transfer device 42 to the transfer rollers 41 by a robot arm or other means.
It is supplied to the upper side and is conveyed toward the other side (the right side in the example in the figure).

A lamp house 43 having the same configuration as that of the previous embodiment is installed on the transport path of the workpiece W by the transport device 42. The lamp house 43 includes an excimer lamp 44 in a sealed interior, and ultraviolet rays from the excimer lamp 44 are transmitted through a light transmitting member 45.
Irradiation is performed on the surface of the workpiece W passing therethrough at a predetermined speed. Although not shown in the drawing, the lamp house 43 is provided with an inert gas introduction mechanism, a cooling water circulation mechanism, and a power supply unit and a control unit of an excimer lamp, as in the above-described embodiment. The introduction and stop of the inert gas into the house 43, the introduction and stop of the cooling water, and the turning on and off of the excimer lamp are controlled.

In the ultraviolet irradiation device 40 according to the present embodiment, when the power of the device is turned on, the transfer roller 41 is driven by the transfer device 42 to enable the transfer of the workpiece W and the excimer lamp. The lamp 44 is turned on to prepare for irradiation of the workpiece W passing therethrough with ultraviolet rays. On the other hand, the introduction and stop of the inert gas into the lamp house 43 by the inert gas introduction mechanism are performed according to a preset operation timing. That is, the introduction and the stop of the inert gas are performed at an independent timing while the excimer lamp 44 is turned on and during the transfer of the workpiece W by the transfer device 42. In one embodiment, a cycle can be repeated in which the introduction of the inert gas is performed in 20 seconds to fill the lamp house, and then the introduction of the inert gas is stopped for the next 20 seconds. In the present embodiment, it is preferable that the cooling water be introduced into the lamp house continuously during the operation of the excimer lamp 44. However, the introduction of the cooling water is performed intermittently as appropriate to reduce consumption. be able to.

As above, one embodiment of the present invention has been described with reference to the drawings. However, it is apparent that the present invention is not limited to the matters described in the above embodiments, and that changes, improvements, and the like can be made based on the description in the claims. For example, in the above-described embodiment, the inflow of the inert gas and the circulation of the cooling water are allowed or prohibited by opening and closing the solenoid valve in accordance with turning on or off of the excimer lamp. However, as for the inflow of the inert gas, it is sufficient that it is possible to guarantee that the flow of the inert gas is stopped during the operation of the excimer lamp, and the switching is provided with a predetermined phase time for turning on or off the excimer lamp. The control may be performed at a timing, or may be controlled at another timing that is not caused by turning on or off. As for the circulation of the cooling water, another timing may be used for the driving of the cooling water as long as the circulation is ensured during the operation of the excimer lamp.

For example, a pressure gauge is provided on the inlet side of the inert gas so as to detect the pressure in the lamp house, and when the pressure in the lamp house becomes lower than a predetermined pressure, the above pressure is introduced. The mouth solenoid valve may be opened to introduce an inert gas into the lamp house. At this time,
The pressure in the lamp house is set to be higher than the atmospheric pressure, and when the pressure in the case becomes equal to the atmospheric pressure due to the leakage of the inert gas in the lamp house, the solenoid valve is opened. be able to.

Further, a concentration meter for detecting the oxygen concentration is provided on the side of the outlet of the inert gas, and the solenoid valve for the inlet is controlled based on the concentration, whereby the required supply amount of the inert gas into the lamp house is controlled. May be controlled.

In the above-described embodiment, the solenoid valve for controlling the flow of the inert gas or the cooling water has only two states, that is, a closed state and an open state, in which the flow is stopped or allowed. However, this may be controlled so as to vary the flow rate of the inert gas or the cooling water. That is, the inert gas solenoid valve is fully opened to make the flow 100% when the excimer lamp is turned off, and the flow is set to 1 when the excimer lamp is turned on.
The flow path may be narrowed so as to limit it to about 0%. The cooling water solenoid valve can be similarly configured.

Further, in the above-described embodiment, the one in which one excimer lamp is provided in the lamp house is shown. However, the present invention can be applied to an ultraviolet irradiation apparatus having a plurality of excimer lamps.

[0072]

As described above, according to the present invention, the wavelength 175
In an ultraviolet irradiation device equipped with a light source capable of irradiating vacuum ultraviolet light of nm or less, it is possible to greatly reduce the amount of inert gas supplied into the lamp house, thereby reducing the running cost. And emissions can be reduced.

Further, in the present invention for controlling the supply of the refrigerant, the amount of the refrigerant used can be greatly reduced.
This also reduces the running cost of operating the ultraviolet irradiation device.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an ultraviolet irradiation device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a cooling water circulation device.

FIG. 3 is a flowchart illustrating an ultraviolet irradiation method according to the present invention.

FIG. 4 is a configuration diagram of an ultraviolet irradiation device according to another embodiment of the present invention.

FIG. 5 is a side view and a cross-sectional view of an excimer lamp having a water-cooled structure.

FIG. 6 is a diagram for explaining an irradiation distance of an ultraviolet ray by an excimer lamp.

FIG. 7 is a configuration diagram of a conventional ultraviolet irradiation device.

[Explanation of symbols]

 W Workpiece 10 Ultraviolet irradiation device 11 Excimer lamp 12 Lamp house 13 Light transmitting member 14 Reflecting mirror 15 Gas inlet 16 Gas outlet 17 Gas supply source 18 Mass flow controller 19 Inlet solenoid valve 20 Outlet solenoid valve 21 Power supply unit 22 Control unit 23 Conveying device 24 Mounting table 30 Cooling water circulation device 31 Impurity removal filter 32 Cooler 33 Liquid feed pump 34 Supply path 35 Discharge path 36 Flow path electromagnetic valve 40 Ultraviolet irradiation device 41 Transport roller 42 Transport device 43 Lamp house 44 Excimer lamp

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B01J 19/12 B01J 19/12 F

Claims (20)

[Claims] 1. An ultraviolet irradiation method for irradiating an ultraviolet ray to a surface to be processed of a workpiece to clean or modify the surface, comprising the steps of: (a) placing a wavelength of 175 nm or less in a closed casing having a light transmitting window; (B) preparing a lamp device having a light source that emits ultraviolet light; and (b) so that ultraviolet light from the light source that passes through the light transmission window and reaches outside the closed casing is emitted to the surface to be processed. (C) introducing an inert gas into the closed casing in parallel with the step of placing the workpiece, and filling the inside of the casing with the inert gas; (D) turning on the light source and stopping the introduction of the inert gas into the sealed housing to irradiate ultraviolet rays to the surface to be processed of the workpiece to clean or modify the surface; (E) After cleaning or modifying the surface to be processed, Comprising a step of discharging the 閉筐 body gases, by repeating the above step (b) ~ (e), an ultraviolet irradiation method of cleaning or modifying the plurality of workpieces. 2. The ultraviolet irradiation method according to claim 1, wherein in the step (d), the introduction of the inert gas into the closed casing is stopped based on a timing at which the light source is turned on. 3. The ultraviolet irradiation method according to claim 1, wherein in the step (e), the gas is discharged based on a timing of turning off the light source. 4. A step of supplying a coolant for cooling the light source to the vicinity of the light source in parallel with the step (d), and a step of stopping the supply of the coolant in parallel with the step (e). The ultraviolet irradiation method according to claim 1, further comprising: 5. A step of supplying a coolant for cooling the light source to the vicinity of the light source at a first supply rate per unit time in parallel with the step (c); In parallel with the step of setting the supply amount of the refrigerant to a second supply amount larger than the first supply amount, and in parallel with the step (e), the supply amount of the refrigerant is changed to the second supply amount. 4. The ultraviolet irradiation method according to claim 1, further comprising a step of returning the supply amount to the first supply amount. 6. The ultraviolet ray according to claim 1, wherein the step (d) is performed while moving the workpiece so that the surface to be processed passes an ultraviolet radiation region of the light source. Irradiation method. 7. An ultraviolet irradiation method for irradiating an ultraviolet ray to a surface to be processed of a workpiece to clean or modify the surface, wherein: (a) a light source is provided in a sealed housing having a light transmitting window. A step of preparing a lamp device; and (b) a step of arranging the workpiece so that ultraviolet rays from the light source that passes through the light transmitting window and reaches the outside of the closed casing are emitted to the surface to be processed. (C) a step of flowing an inert gas into the closed casing at a first flow rate per unit time in parallel with the step of installing the workpiece, and (d) turning on the light source and , The flow rate of the inert gas flowing into the closed casing per unit time
A step of irradiating ultraviolet rays to the surface to be processed of the workpiece and cleaning or modifying the same while reducing the flow rate to a second flow rate smaller than the flow rate of (e) cleaning or modifying the surface to be processed; After the reforming is completed, the flow rate of the inert gas flowing into the closed casing is adjusted to the second flow rate.
Returning to the first flow rate from the above flow rate. 8. The ultraviolet irradiation method according to claim 7, wherein in the step (d), the flow rate of the inert gas into the closed casing is reduced based on a timing at which the light source is turned on. 9. The ultraviolet irradiation method according to claim 8, wherein in the step (e), the flow rate of the inert gas is returned to the first flow rate based on a timing of turning off the light source. 10. The ultraviolet irradiation method according to claim 7, wherein, in the step (d), the flow rate of the inert gas into the closed casing is reduced based on a change in the pressure in the closed casing. 11. A step of supplying a coolant for cooling the light source to the vicinity of the light source in parallel with the step (d), and a step of stopping the supply of the coolant in parallel to the step (e). The ultraviolet irradiation method according to any one of claims 7 to 10, further comprising: 12. A step of supplying a coolant for cooling the light source to the vicinity of the light source at a first supply rate per unit time in parallel with the step (c); In parallel with the step of setting the supply amount of the refrigerant to a second supply amount larger than the first supply amount, and in parallel with the step (e), the supply amount of the refrigerant is changed to the second supply amount. The ultraviolet irradiation method according to claim 7, further comprising: returning the supply amount to the first supply amount. 13. The ultraviolet ray according to claim 7, wherein the step (d) is performed while moving the workpiece so that the surface to be processed passes an ultraviolet radiation area of the light source. Irradiation method. 14. An ultraviolet irradiation method for irradiating an ultraviolet ray to a surface to be processed of a workpiece to clean or modify the surface, wherein: (a) a wavelength of 175 nm or less in a closed casing having a light transmitting window; (B) preparing a lamp device having a light source that emits ultraviolet light, and (b) emitting ultraviolet light from the light source that passes through the light transmitting window and reaches outside the closed casing to the processing surface. (C) passing the plurality of workpieces under the ultraviolet radiation region in parallel with the step of passing the plurality of workpieces under the ultraviolet radiation region; After introducing an inert gas into the casing and filling the interior with the inert gas,
Repeating the step of stopping the introduction of the inert gas;
And an ultraviolet irradiation method for cleaning or modifying a plurality of workpieces. 15. An ultraviolet irradiation apparatus for irradiating an ultraviolet ray to a surface to be processed of a workpiece to clean or modify the surface, wherein an ultraviolet ray having a wavelength of 175 nm or less is introduced into a closed casing having a light transmitting window. A lamp device having a light source that emits light; and a base on which the workpiece is installed so that ultraviolet light from the light source that passes through the light transmitting window and reaches outside the sealed housing is emitted to the surface to be processed. And an inert gas introducing means for introducing an inert gas into the closed casing, and while the light source is turned on to irradiate ultraviolet rays to the processing surface of the workpiece to perform cleaning or modification thereof. A control unit for prohibiting an inert gas from flowing into the closed casing. 16. The ultraviolet irradiation apparatus according to claim 15, wherein the control means prohibits an inert gas from flowing into the closed casing based on a timing at which the light source is turned on. 17. The ultraviolet irradiation device according to claim 15, wherein the control unit discharges gas from the closed casing based on a timing of turning off the light source. 18. A coolant supply means for supplying a coolant for cooling the light source to the vicinity of the light source, and turning on the light source to radiate ultraviolet rays to a surface of the workpiece to clean or modify the surface. The ultraviolet irradiation device according to any one of claims 15 to 17, further comprising: a control unit configured to stop the supply of the refrigerant or reduce the supply amount of the refrigerant except during the period when the operation is performed. 19. The ultraviolet irradiation apparatus according to claim 15, further comprising a moving unit configured to move the work so that the work surface passes through an ultraviolet radiation region of the light source. 20. An ultraviolet irradiation apparatus for irradiating an ultraviolet ray to a surface to be processed of a workpiece to clean or modify the surface, wherein an ultraviolet ray having a wavelength of 175 nm or less is introduced into a closed casing having a light transmitting window. A lamp device having a light source that emits light; and a plurality of the workpieces being irradiated with the ultraviolet light so that ultraviolet light from the light source that passes through the light transmitting window and reaches outside the sealed housing is emitted to the surface to be processed. Moving means for sequentially passing under the radiation region of the above, inert gas introduction means for introducing an inert gas into the closed casing, and the plurality of workpieces sequentially pass below the ultraviolet radiation region. Control means for repeatedly introducing an inert gas into the closed casing, filling the casing with the inert gas, and then stopping the introduction of the inert gas.