JP2000216127A - Apparatus and method for treating substrate with ultraviolet irradiation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To more efficiently irradiate a short-wavelength ultrasonic beam on the surface of a treating substrate, without sealing a lamp house housing an excimer lamp. SOLUTION: A lamp houses 12 housing an excimer clamp 1 is a container opened at the lower end, an opening of its lower end faces the surface of a substrate 10, and an N-gas feed pipe 13 for feeding inert gas of nitrogen is connected to the top thereof. At the upstream of the substrate 10 running line an oxygen-contg. gas entrance passage 14 is connected for introducing, e.g. an oxygen-contg. gas such as ozone-contg. dry air, etc., and the oxygen-contg. gas entrance part 14 is capable of introducing the oxygen-contg. gas at a low angle to the substrate 10 running line, thereby forming an oxygen-contg. gas layer of a specified thickness on the substrate 10 surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate processing apparatus for irradiating a surface of a transparent substrate of a liquid crystal panel, a semiconductor wafer, a magnetic disk substrate, an optical disk substrate or the like with ultraviolet rays to perform processing such as cleaning and etching. And a processing method.

[0002]

2. Description of the Related Art For example, a pattern such as a transparent electrode is formed on a surface of a TFT substrate constituting a transparent substrate such as glass constituting a liquid crystal panel by a film forming means. In the manufacturing process of such a substrate, processes such as cleaning and etching are performed, and these processes are generally performed by a wet process system in which a predetermined processing solution is applied or sprayed. . However, in recent years, even in a dry process by irradiating ultraviolet rays,
Processing such as cleaning and etching has been performed.

For example, Japanese Patent Application Laid-Open No. Hei 5-224167 discloses a method for cleaning a glass substrate of a liquid crystal panel.
Prior to performing a wet process using a cleaning liquid, an apparatus is disclosed in which a substrate is irradiated with ultraviolet rays so that more efficient cleaning can be performed. That is, in this known cleaning method, as a pre-process of cleaning the substrate by spraying the cleaning liquid, the surface of the substrate is irradiated with ultraviolet rays from a low-pressure mercury lamp to chemically remove organic substances attached to the surface of the substrate. In addition, by improving the wettability of the surface, that is, by reducing the contact angle, inorganic dirt can be efficiently removed at the time of washing with a shower or the like. Here, the ultraviolet light emitted from the low-pressure mercury lamp has a wavelength of approximately 185 nm.
And has a peak at 254 nm, and has such a peak wavelength characteristic, and the organic substances attached to the substrate surface can be removed by the ultraviolet light. As a mechanism of this organic substance cleaning, the chemical bond constituting the organic substance is decomposed by the irradiation energy of the ultraviolet ray to lower the molecular weight and activate the organic substance. At the same time, oxygen in the air absorbs ultraviolet rays to generate ozone, and this ozone is converted into active oxygen. CO _X H
_It is converted to volatile substances such as ₂ O and NO _X and released into the air to be removed.

Since the wavelength of ultraviolet light emitted from a low-pressure mercury lamp is 185 nm on the short wavelength side, even organic substances adhered to a substrate having a strong chemical bond energy such as a double bond. May not be disassembled. Therefore, in order to clean the substrate more completely, ultraviolet rays having a shorter wavelength must be irradiated.

In consideration of the above points, Japanese Patent Application Laid-Open No. 6-3121
Japanese Patent No. 30 proposes a method of performing dry cleaning by irradiating ultraviolet rays from a dielectric barrier discharge excimer lamp (hereinafter simply referred to as an excimer lamp) to the substrate surface.

An excimer lamp emits ultraviolet light by generating excimer molecules between an inner tube and an outer tube made of quartz glass. To this end, a discharge gas containing xenon or a mixed gas of argon and chlorine is sealed between the inner tube and the outer tube, and an electrode serving as a reflector is provided on the inner surface of the inner tube, and the outer surface of the outer tube is provided. Is made of, for example, a metal wire mesh, and is provided with an electrode through which light can pass. Then, by passing an alternating current between these two electrodes, short-wavelength ultraviolet light is emitted by excimer light emission. Here, in an excimer lamp in which xenon (Xe) gas is sealed as a discharge gas, the emitted ultraviolet light is monochromatic light having a short wavelength of 172 nm. Is quickly and efficiently generated, which is extremely advantageous in performing dry cleaning of a substrate or the like. In the following description, the former is referred to as UV, and the latter is referred to as VUV in order to distinguish between ultraviolet light emitted from a low-pressure mercury lamp and short-wavelength ultraviolet light emitted from an excimer lamp.

[0007]

By the way, the VUV emitted from the excimer lamp is one of the low-pressure mercury lamps.
Compared to UV with wavelengths of 85 nm and 285 nm, the attenuation factor in air is extremely high, and at a position 5 mm away from the lamp, VUV is attenuated by about 80%. To suppress this energy loss, the distance from the lamp must be 3
mm (the attenuation factor at this distance is about 40%) or less. In consideration of the mounting error of the lamp and the like, the substrate must be actually arranged at a position of about 1 mm with respect to the lamp, and the positioning mechanism of the substrate becomes extremely complicated. If the distances are too close, there is also a problem that even if there is a slight difference in the distance between the distances, the irradiation light becomes non-uniform, causing uneven cleaning.

By the way, ultraviolet rays and VUV emitted from the above-mentioned excimer lamp hardly attenuate under an inert gas atmosphere such as nitrogen gas (N ₂ gas). Therefore, if the excimer lamp is arranged in a sealed lamp house and the inside of the lamp house is kept in an inert gas atmosphere, attenuation of VUV can be suppressed. However, it is necessary to generate ozone and active oxygen on the surface side of the substrate. To this end, if the lamp house is hermetically sealed, and a window for emitting VUV is provided on the surface facing the substrate, and the window is configured to emit VUV toward the substrate,
VUV attenuation can be suppressed. According to this structure, the space between the window of the lamp house and the substrate can be finely adjusted, so that a space or a gap required for generating active oxygen can be formed between the window and the substrate. In addition, depending on the arrangement position of the excimer lamp in the lamp house, the lamp can be arranged so as to irradiate a uniform amount of VUV from the window, so that uniform and efficient cleaning can be performed.

Here, the windows provided in the lamp house are:
Naturally, it must be made of a material having a high transmittance for VUV. As a member having a high VUV transmittance, for example, there is synthetic quartz glass such as Sprazil (trade name of Shin-Etsu Quartz Co., Ltd.). However, this kind of synthetic quartz glass is expensive, and when irradiated with VUV through a window made of this synthetic quartz glass, the glass deteriorates early and is devitrified, and its life is short. Quartz glass constituting the window must be frequently replaced as a replacement part, which results in an extremely high running cost of the apparatus. Even though the transmittance is high, since VUV is radiated through the window,
There is also a problem that the UV irradiation efficiency is reduced.

The present invention has been made in view of the above points, and an object of the present invention is to provide a light source having a short wavelength on the surface of a substrate to be processed without sealing a lamp house in which an excimer lamp is mounted. An object of the present invention is to make it possible to irradiate ultraviolet rays more efficiently.

[0011]

In order to achieve the above-mentioned object, a substrate processing apparatus using ultraviolet irradiation according to the present invention includes a lamp house having an opening on a side facing a surface of a substrate to be processed; An excimer lamp mounted therein, an inert gas supply unit for supplying an inert gas to the lamp house in a pressurized state, and an oxygen-containing gas supplied from a predetermined angle to the surface of the substrate. An oxygen-containing gas introducing portion for forming a gas layer containing oxygen of a predetermined thickness on the surface of the substrate is provided.

Here, air can be used as the oxygen-containing gas supplied from the oxygen-containing gas introduction section, and the air is desirably dry air, particularly clean air containing no dust. In addition, a mixed gas of dry air and ozone can be used. When ozone is contained, not only is active oxygen generated more efficiently, but also gas containing ozone has a large specific gravity, so that gas in a rectified state can be used. The layer is formed more reliably. The substrate to be processed can be processed in a stationary state. However, if the processing is performed while the substrate is being transported by the transporting means, the oxygen-containing gas introduction unit moves the substrate in the transport direction with respect to the surface of the substrate. It is more preferable that the oxygen-containing gas is supplied to the front in order to form the gas layer in a rectified state. Examples of the excimer lamp include a dielectric barrier discharge excimer lamp and an RF discharge excimer lamp, and any of these may be used.
For example, when a dielectric barrier discharge excimer lamp is used and xenon gas is sealed as the discharge gas, the wavelength of the ultraviolet light emitted from the excimer lamp becomes 172 nm.

Further, according to the substrate processing method of the present invention, the lamp house may be irradiated with light from an excimer lamp provided in a lamp house having one end opened through the opening. The inside of the substrate is filled with an inert gas in a pressurized state, and an oxygen-containing gas layer having a predetermined thickness is formed on the surface of the substrate.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. First, FIGS. 1 and 2 show a schematic configuration of an excimer lamp used in the substrate processing apparatus of the present invention. In the figure, 1 indicates an excimer lamp,
The excimer lamp 1 includes an inner tube portion 2 and an outer tube portion 3 integrally formed of quartz glass, has an annular quartz glass tube 4, and the inside of the quartz glass tube 4 is a sealed discharge tube. It is space 5. A metal electrode 6 made of a cylindrical metal plate is provided inside the inner tube 2 so as to be fixed to the inner tube 2. A wire mesh electrode 7 is provided on the outer peripheral surface of the outer tube portion 3. An AC power supply 8 is connected between the metal electrode 6 and the wire mesh electrode 7. further,
The inside of the inner tube portion 2 is used as a passage for a cooling fluid (for example, cooling water) for cooling the metal electrode 6.

A discharge gas is sealed in the quartz glass tube 4. When a high AC voltage is applied between the metal electrode 6 and the wire mesh electrode 7, a dielectric gas between the inner tube portion 2 and the outer tube portion 3 is generated. Discharge plasma (dielectric barrier discharge) is generated between the bodies, and atoms of the discharge gas are excited by the discharge plasma to be in an excimer state. Then, when returning from the excimer state to the ground state, excimer light emission occurs. The emission spectrum at this time differs depending on the discharge gas sealed in the quartz glass tube 4. However, the use of xenon (Xe) gas results in emission of monochromatic light having a center wavelength of 172 nm.
If argon (Ar) gas is used as the discharge gas, the center of the emission wavelength is 126 nm. The metal electrode 6 functions as a reflector, and the wire mesh electrode 7 functions substantially as a transparent electrode.
That is, VUV is irradiated from the outer tube 3 side. In this case, the filling pressure of the xenon gas is, for example, 350 Torr.
Degree.

Next, using the above excimer lamp 1,
For example, FIG. 3 shows a schematic configuration of a transparent substrate cleaning apparatus constituting a liquid crystal display panel. In the figure, reference numeral 10 denotes a substrate to be cleaned, and the substrate 10 is moved in a direction indicated by an arrow in the figure by a transfer base 11 provided on a transfer means such as a conveyor. Here, the transport base 11 is omitted from the illustration,
At least the height position of the substrate 10 can be adjusted.

Reference numeral 12 denotes a lamp house. The lamp house 12 is formed of a container having an open lower end, and an excimer lamp 1 is provided therein. Here, the lower end of the lamp house 12 faces the surface of the substrate 10 in a non-contact state, and by adjusting the height of the substrate 10 transferred by the transfer base 11, the surface and the lamp house 12 are adjusted. 12 is controlled. A nitrogen gas supply pipe 13 for supplying a nitrogen gas (N ₂ gas) as an inert gas is connected to an upper portion of the lamp house 12. An oxygen-containing gas introduction passage 14 for introducing an oxygen-containing gas such as dry air containing ozone gas is connected. Here, the oxygen-containing gas introduction passage 14 is configured to introduce the oxygen-containing gas at a shallow angle with respect to the surface of the substrate 10, for example, about 5 to 45 °, and the opening position into the lamp house 12 is The position is extremely close to the substrate 10.

With the above configuration, the interior of the lamp house 12 in which the excimer lamp 1 is turned on is filled with nitrogen gas, and the substrate 10 is transferred to the transfer base 1.
The oxygen-containing gas is supplied from the oxygen-containing gas introduction passage 14 while being conveyed by the lamp 1 and passing through the lamp house 12. As a result, V emitted from the excimer lamp 1
UV contaminants made of organic substances adhering to the surface of the substrate 10 being transported are decomposed, and the decomposed organic substances are converted into volatile substances by generation of active oxygen. This volatile substance is generated by the flow of the oxygen-containing gas and the nitrogen gas toward the front in the traveling direction of the substrate 10, and the lamp house 12 and the substrate 1
It is released to the outside through a gap between the two. As a result, the surface of the substrate 10 is dry-cleaned, and
The contact angle on the surface of No. 0 is reduced, and the wettability is improved. Therefore, if shower cleaning etc. are performed in the subsequent process,
Inorganic contaminants adhering to the substrate 10 can be easily and completely removed, and the substrate 10 can be cleaned in an extremely clean state.

As described above, oxygen needs to be present between the excimer lamp 1 and the substrate 10, but if a large amount of oxygen is present, the VUV is significantly attenuated. Must be done.
However, since the attenuation of VUV is suppressed in a nitrogen gas atmosphere containing no oxygen, an oxygen-containing gas layer GL is formed between the excimer lamp 1 and the substrate 10 on the surface side of the substrate 10 and the lamp house 12 The inside is filled with nitrogen gas. That is, the excimer lamp 1 and the substrate 10
Even without providing a window or the like for partitioning between them, the nitrogen gas atmosphere state containing no oxygen is reliably maintained except for the oxygen-containing gas layer GL having a predetermined thickness. Therefore, by setting the thickness of the oxygen-containing gas layer GL to a desired size, the VUV radiated from the excimer lamp 1 has a function of decomposing chemical bonds required for removing organic substances from the substrate 10 and a function of active oxygen. Is maintained in a state in which both functions of generating the

When the gas is supplied obliquely to the wall surface, a gas flow is formed along the wall surface. In particular, when the wall surface moves, the gas flows toward the front in the moving direction. If the gas flows, it will flow as a very stable laminar flow. In the lamp house 12, the oxygen-containing gas is introduced from the oxygen-containing gas introduction passage 14 at a shallow angle toward the surface of the substrate 10, so that the laminar flow of the oxygen-containing gas along the surface of the substrate 10, that is, the oxygen-containing gas, Gas layer G
L is formed. In addition, when the lamp house 12 is pressurized to some extent by the nitrogen gas, a pressing force acts on the oxygen-containing gas layer GL, so that laminar flow is further promoted. Further, when an ozone gas having a large specific gravity is mixed as the oxygen-containing gas in addition to the dry air, the adhesion of the oxygen-containing gas to the substrate 10 is further improved. Therefore, the angle of the oxygen-containing gas introduction passage 14 with respect to the substrate 10, the flow rate and pressure of the nitrogen gas supplied from the nitrogen gas supply pipe 13, the transport speed of the substrate 10, the gap between the lamp house 12 and the substrate 10, and the like are managed. Then, the thickness of the oxygen-containing gas layer GL can be arbitrarily controlled.

Further, even if the excimer lamp 1 is separated from the substrate 10 in the lamp house 12, the VUV does not significantly attenuate.
By keeping the distance from zero to some extent, uniform and uniform cleaning can be achieved. Moreover, the excimer lamp 1 and the substrate 10
Since there is no need to interpose a quartz glass window or the like between them, VUV attenuation can be further suppressed, cleaning efficiency can be further improved, and an inexpensive device can be configured.

In the above-described embodiment, dry air containing no foreign matter or moisture is used as the oxygen-containing gas. However, it is only necessary to use a gas containing oxygen at a predetermined ratio. Then, the above-described substrate 10
Although not only the adhesion to the substrate is improved, but also the production of active oxygen is expedited, it is not always necessary to mix ozone gas with the oxygen-containing gas. Further, the processing is performed while the substrate 10 is transported by the transport base 11. However, if a large number of excimer lamps are mounted in the lamp house, the substrate 10 does not always need to be run. Furthermore, although it has been described that dry cleaning is performed on the substrate 10, it is needless to say that the present invention can be applied not only to dry cleaning but also to etching and other processes. Furthermore, excimer lamp 1
Although the xenon gas is sealed in the discharge space 5 in the above, another discharge gas such as argon gas, krypton chloride gas or the like may be sealed.

[0023]

As described above, according to the present invention, the surface of the substrate to be processed can be more efficiently irradiated with ultraviolet light having a short wavelength even if the lamp house in which the excimer lamp is mounted is not sealed. As a result, it is possible to perform the predetermined processing on the substrate more quickly and efficiently.

[Brief description of the drawings]

FIG. 1 is a structural explanatory view of a dielectric barrier discharge excimer lamp as an example of an excimer lamp used in a substrate processing apparatus of the present invention.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is a schematic configuration diagram of an apparatus for cleaning a substrate using an excimer lamp.

4 is an enlarged view of a portion A in FIG. 3 for explaining an oxygen-containing gas layer formed on a substrate.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Excimer lamp 10 Substrate 11 Transport base 12 Lamp house 13 Nitrogen gas supply pipe 14 Oxygen-containing gas introduction passage

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C23G 5/00 C23G 5/00 (72) Inventor Isamu Akiha 3-16-3 Higashi 3-chome, Shibuya-ku, Tokyo Hitachi Electronic Engineering Co., Ltd. F term (reference) 3B116 AA02 AA03 AB14 BC01 4G075 AA24 AA30 BC06 BC10 CA03 CA33 CA51 CA63 EB31 EC21 FB02 FB06 FC04 4K053 PA01 PA13 QA04 QA07 RA02 SA01 SA20 YA17 4K057 DA01 DB06 DB20 DD10 DE14

Claims (5)

[Claims] 1. A lamp house having an opening on a side facing a surface of a substrate to be processed, an excimer lamp mounted in the lamp house, and an inert gas supplied into the lamp house in a pressurized state. An active gas supply unit, an oxygen-containing gas supply unit for supplying an oxygen-containing gas from a predetermined angle to the surface of the substrate, and forming a gas layer containing oxygen of a predetermined thickness on the surface of the substrate; A substrate processing apparatus using ultraviolet irradiation, comprising: 2. The apparatus according to claim 1, wherein the oxygen-containing gas supplied from the oxygen-containing gas introduction unit is dry air or a mixed gas of dry air and ozone. 3. The substrate passes through a lower portion of the lamp house while being transported in a predetermined direction by a transporting means. 2. The apparatus according to claim 1, wherein the oxygen-containing gas is supplied forward in the transport direction. 4. The apparatus according to claim 1, wherein the excimer lamp is a dielectric barrier discharge excimer lamp, and a discharge gas sealed in the excimer lamp is a xenon gas. 5. While the irradiation light from an excimer lamp provided in a lamp house having one end opened is irradiated onto the surface of the substrate through the opening, an inert gas is pressurized in the lamp house. And forming an oxygen-containing gas layer having a predetermined thickness on the surface of the substrate.