JP2007149938A - Substrate processing apparatus, substrate processing method and display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently execute hydrophilic processing for a substrate by utilizing irradiation energy of an ultraviolet ray from a discharge lamp to its maximum. <P>SOLUTION: While the substrate 1 is substantially horizontally transferred by a transfer means 2, the discharge lamp 3 provided in a processing chamber 4 irradiates a processed surface 1A of the substrate 1 with an ultraviolet ray of 172 nm from a distance of not more than 3 mm, and a wet inert gas containing steam of 55-80% is supplied to a gas reservoir 7 from a supply piping 5 in the processing chamber 4. A downflow in a laminar flow state is formed in the processing chamber 4, organic substances adhering on the processed surface 1A are decomposed and become low molecules, and the steam in an atmosphere is decomposed and the decomposed substances react with oxidizing radicals and reducible radicals and radiated in air. Thus, hydrophilic processing of the processed surface 1A of the substrate 1 is performed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a substrate processing apparatus and a processing method for hydrophilizing a substrate such as a flat panel display such as a liquid crystal display, a PDP, and an organic EL panel, a semiconductor wafer, a magnetic disk substrate, and an optical disk substrate, and the processing method. The present invention relates to a display device having a substrate processed by the above method.

  For example, a flat panel display constituting a liquid crystal display is composed of two glass substrates, and a circuit pattern, a color filter, and the like are formed on this substrate. As a pre-stage of substrate cleaning, development for etching, and other processing, hydrophilic treatment is performed to remove organic stains from the substrate surface and reduce the contact angle. For this reason, a dielectric barrier discharge lamp that irradiates the substrate surface with ultraviolet light having a main wavelength of 172 nm is used to decompose and remove organic substances adhering to the substrate surface. Yes.

In the hydrophilization treatment, ultraviolet light from the dielectric barrier discharge lamp is irradiated toward the substrate surface while the substrate is transported in the horizontal direction by the transport means, and this ultraviolet light irradiation area is inactivated by being humidified. Patent Document 1 discloses a gas atmosphere, specifically, a nitrogen gas atmosphere containing water vapor, which allows an organic substance to be decomposed more efficiently. In this way, by reducing the irradiation energy of ultraviolet light by setting the nitrogen gas atmosphere, and by mixing the water vapor with the gas, the organic substance decomposed and reduced in molecular weight can only be oxidized. In addition, since a reduction reaction can also be caused, the hydrophilic treatment is performed more efficiently.
JP 2001-137800 A

    By the way, in the processing method disclosed in Patent Document 1, a dielectric barrier discharge lamp is used. This discharge lamp is housed in a lamp house filled with an inert gas, and ultraviolet light in this lamp house is contained. The irradiation part is provided with an irradiation window made of quartz glass, or when no quartz glass is provided, the end of the lamp house is arranged at a position very close to the substrate. And the inert gas in the inside of a lamp house has enclosed the dry gas which does not contain water vapor | steam. For this reason, the discharge lamp and the substrate are separated from each other, and energy loss of ultraviolet light is generated according to the distance between the discharge lamp and the substrate. In addition, the wet inert gas humidified is supplied between the lamp house and the substrate. However, when the discharge lamp and the substrate are brought close to each other, the wet inert gas cannot be reliably fed between them. Become. In particular, when an irradiation window is provided in the lamp house, the wrapping of the humidified inert gas becomes worse, and a sufficient amount of water vapor may not be supplied to the irradiation area of the discharge lamp. Furthermore, when an irradiation window made of quartz glass is not provided, it is necessary to prevent the supplied wet inert gas from going to the periphery of the discharge lamp. For this purpose, it is necessary to adjust the supply amount of the wet inert gas. There is a problem that there is.

  The present invention has been made in view of the above points, and an object of the present invention is to perform hydrophilic treatment on a substrate more efficiently by making maximum use of irradiation energy of ultraviolet light from a discharge lamp. Is to be able to.

  In order to achieve the above-described object, in the present invention, a processing region is set in the middle of a transport path for transporting a substrate in a state of being horizontal or inclined with the substrate surface facing upward, by the substrate transport means, In this processing region, a wet inert gas atmosphere is formed by flowing a wet inert gas humidified with water vapor as a downflow from above over a predetermined length in the substrate transport direction, and the wet inert gas atmosphere In addition, a method of disposing a discharge lamp for irradiating ultraviolet light at a position close to the substrate transfer surface constituting the transfer path and performing a hydrophilic treatment on the substrate surface introduces the substrate into the processing region. By replacing the air located on the substrate surface with a wet inert gas, ultraviolet light from the discharge lamp is emitted under the wet inert gas atmosphere. It is characterized by a step of irradiating the substrate surface from a distance.

  Here, the discharge lamp is composed of an inner tube portion covering the metal electrode and an outer tube portion provided at a predetermined interval in the inner tube portion, and a discharge gas is provided between the inner tube portion and the outer tube portion. And a ground electrode around the outer tube. When xenon gas is used as the discharge gas, the dominant wavelength of ultraviolet light is 172 nm. Further, when argon gas is used as a discharge gas, ultraviolet light of 126 nm can be irradiated. As the earth electrode of the discharge lamp, an earth electrode which is not exposed to the outside and whose outer periphery is covered with a ceramic protective layer such as quartz can be used. This discharge lamp is preferably arranged at a distance of 3 mm or less with respect to the substrate. The wet inert gas supplied to the treatment region is humidified with water vapor, and it is desirable to use 55 to 80% nitrogen gas.

  Further, the substrate processing apparatus according to the present invention is provided with a substrate transfer means for transferring a substrate in a horizontal or inclined state with its processing surface facing upward, and in the middle of the substrate transfer path by the substrate transfer means. Supply means for flowing down the wet inert gas humidified with water vapor toward the substrate transfer means by downflow, and laminating the wet inert gas supplied from the supply means, A laminar flow means for flowing out over a predetermined length; and a wet inert gas atmosphere formed by the laminar flow means, and disposed in a position near the substrate transfer surface by the substrate transfer means. An inner tube portion that covers the metal electrode and an outer tube portion provided at a predetermined interval in the inner tube portion, and a discharge gas is sealed between the inner tube portion and the outer tube portion, In addition, around the outer pipe An earth electrode is provided, and the earth electrode is further provided with a ceramic protective layer. The earth electrode is composed of one or more discharge lamps that irradiate ultraviolet light toward the substrate surface from a close range. It is characterized by that.

  Furthermore, as another substrate processing apparatus according to the present invention, a substrate transport means for transporting a substrate in a horizontal or inclined state with its processing surface facing upward, and a substrate transport path by the substrate transport means A supply means that is provided in the middle and flows down toward the substrate transport means by downflow of wet inert gas humidified by 55 to 80% water vapor, and laminar flow of the wet inert gas supplied from the supply means A laminar flow means for flowing out over a predetermined length of the substrate transport path, and a wet inert gas atmosphere formed by the laminar flow means, wherein the substrate transport means An inner tube portion that is disposed near the transfer surface and covers the metal electrode, and an outer tube portion provided at a predetermined interval on the inner tube portion. The inner tube portion and the outer tube portion Discharge gas between Is further provided with a ground electrode around the outer tube, and the ground electrode is further provided with a ceramic protective layer. Ultraviolet light having a main wavelength of 172 nm is 3 mm or less. It is characterized in that it is composed of one or a plurality of discharge lamps that irradiate the surface of the substrate from the distance.

  Here, the substrate to be processed is made of glass, semiconductor, ceramics, metal, or the like, and is formed of a rectangular or circular thin plate. The substrate is a flat panel display such as a liquid crystal display, PDP, or organic EL panel, a semiconductor wafer, a magnetic disk substrate, an optical disk substrate, or the like. As processing steps, for example, dry cleaning processing to remove organic dirt from the surface of the substrate, and hydrophilic treatment to reduce the contact angle of the substrate surface as a pre-process of etching to form a circuit pattern are targeted. Become.

  By bringing the discharge lamp close to the substrate, the irradiation energy of the ultraviolet light to the substrate is increased to promote the lowering of the molecular weight of the organic substance adhering to the substrate, and the abundant wetness that exists between the substrate and the discharge lamp. Impurities whose molecular weight is reduced by the active gas can be reacted more efficiently, and thus the hydrophilic treatment of the substrate can be performed very efficiently.

    Hereinafter, embodiments of the present invention will be described with reference to the drawings. In FIG. 1, reference numeral 1 denotes a substrate to be processed. This substrate 1 is transported by a transport unit 2 in the direction of the arrow in FIG. 1. The transport means 2 transports the substrate 1 horizontally with its processing surface 1A facing upward, and a hydrophilic treatment is performed on the processing surface 1A of the substrate 1. The substrate 1 can be transported not only in a horizontal state but also in a state where the surface 1A to be processed is tilted left and right with respect to the transport direction or tilted back and forth. However, this inclination angle is a relatively small angle of about several degrees to several tens of degrees, regardless of the direction of inclination. A discharge lamp 3 for irradiating the substrate 1 with ultraviolet light is provided at an upper position on the transport surface at a position midway along the transport path of the substrate 1 by the transport means 2. Here, although two discharge lamps 3 are provided in FIG. 1, the number of discharge lamps 3 is not limited to this, and may be an appropriate number depending on the purpose of the processing.

  A portion where the discharge lamp 3 is provided is a processing region for the substrate 1, and this processing region is placed in a wet inert gas atmosphere. For this purpose, a processing chamber 4 having an open lower end is provided, and the discharge lamp 3 is arranged in the processing chamber 4. Here, the processing chamber 4 includes a surrounding wall portion 4 a and a top plate portion 4 b, and the width dimension of the surrounding wall portion 4 a is slightly larger than the width dimension of the substrate 1. A supply pipe 5 is connected to the top plate portion 4b, and nitrogen gas humidified as a wet inert gas is supplied from the supply pipe 5. A punching board 6 is mounted at a position below the top plate portion 4 b in the processing chamber 4, and a gas storage portion 7 is formed at an upper position inside the processing chamber 4 by the punching board 6. Inside the processing chamber 4, wet inert gas flows out from the through holes 6 a in the punching board 6, and a down flow is formed. Therefore, there is a laminarization means for making the wet inert gas flow down in a laminar flow state in the processing chamber 4 by the gas storage chamber 7 partitioned by the punching board 6 and the through holes 6a provided in the punching board 6. Composed. Here, the discharge lamp 3 provided in the processing chamber 4 is positioned in parallel with the substrate 1. Therefore, when the substrate 1 is tilted left and right with respect to the transport direction, it is desirable that the discharge lamp 3 is also tilted at the same angle.

  As the wet inert gas, nitrogen gas containing water vapor is used. And the mixing rate of water vapor | steam shall be a high water vapor | steam density | concentration like 55 to 80%, and water vapor | steam shall consist of pure water preferably. The wet inert gas does not cause turbulent flow in the chamber 4 at least when the substrate 1 is not interposed, and the entire inside of the chamber 4 is replaced with air by the wet inert gas. The flow rate.

  The discharge lamp 3 has a configuration schematically shown in FIG. The discharge lamp 3 has a cylindrical shape, and a metal electrode 10 is disposed at the center thereof, and a double tube comprising an inner tube portion 11 and an outer tube portion 12 so as to surround the metal electrode 10. Is provided. Both the inner tube portion 11 and the outer tube portion 12 are made of quartz glass, and a space between the inner tube portion 11 and the outer tube portion 12 is a discharge space 13, and the discharge space 13 has xenon as a discharge gas. Gas is sealed. A pattern of the ground electrode 14 is formed on the outer surface of the outer tube portion 12. The ground electrode 14 has, for example, a wire mesh shape, and is formed by a technique such as forming a metal film on the surface of the outer tube portion 12 and performing etching to form a wire mesh pattern. Therefore, by passing a predetermined alternating current between the metal electrode 10 and the earth electrode 14, the xenon gas is excited and the ultraviolet light having a wavelength of 172 nm as a main wavelength is irradiated. The protective layer 15 is formed by coating quartz so as to cover the ground electrode 14 formed on the surface of the outer tube portion 12 in the discharge lamp 3 so that the ground electrode 14 is not exposed to the outside.

  The substrate 1 is transported by the transport means 2 in the direction of the arrow in FIG. In the processing chamber 4, the wet inert gas is supplied from the supply pipe 5 to the gas storage chamber 7, and this wet inert gas passes through the through holes 6 a of the punching board 6, thereby forming a laminar flow downflow. The Therefore, air is excluded from the inside of the processing chamber 4 to form a wet inert gas atmosphere. Further, since the discharge lamp 3 is operating and xenon gas is used as the discharge gas, ultraviolet light having a main wavelength of 172 nm is irradiated from the discharge lamp 3.

When the substrate 1 passes through the lower position of the processing chamber 4, the organic substance adhering to the processing surface 1A is decomposed by the action of the ultraviolet light irradiated toward the processing surface 1A of the substrate 1. The molecular weight will be reduced. At the same time, water vapor in the atmosphere is decomposed to generate oxidizing radicals and reducing radicals. As a result, the decomposed organic substance is finally converted into a volatile substance such as COx, H ₂ O, NOx by an oxidation reaction and a reduction reaction, and removed so as to be released into the air. As a result, the organic fouling substances are removed from the surface 1A to be processed of the substrate 1, and a hydrophilic treatment is performed in which the contact angle is reduced.

  Here, in order to perform the hydrophilic treatment of the substrate 1 more efficiently, the discharge lamp 3 is brought as close to the surface of the substrate 1 as possible, and the atmosphere between the discharge lamp 3 and the substrate 1 is not wet with water vapor. It must be replaced with active gas so that it does not contain air. Although the discharge lamp 3 is disposed in an atmosphere containing water vapor, a protective layer 15 made of quartz is formed on the outermost part of the discharge lamp 3 and the ground electrode 14 is not exposed to the outside. There is no risk of deterioration such as oxidation of the ground electrode 14 even if it is not arranged in the compartment covered with. Therefore, the discharge lamp 3 can be disposed at a position close to the substrate 1, and preferably, the distance between the discharge lamp 3 and the surface 1A to be processed of the substrate 1 can be set to a distance of 3 mm or less. As a result, the attenuation of the ultraviolet light irradiated from the discharge lamp 3 can be suppressed as much as possible, and the decomposition ability of the organic substance with respect to the surface 1A to be processed of the substrate 1 can be remarkably increased.

  Since the down flow of the wet inert gas is formed downward from the inside of the processing chamber 4, the space between the discharge lamp 3 and the substrate 1 is surely filled with the wet inert gas. Since no air is present in the air, the generation of oxidizing and reducing radicals due to the decomposition of water vapor becomes remarkable, the ability to remove organic substances is remarkably increased, and the consumption of wet inert gas can be reduced. . Furthermore, this wet inert gas can also function as a cooling fluid for cooling the discharge lamp 3, so that it is not necessary to provide the discharge lamp 3 with a special cooling function.

  From the above, the hydrophilization capability for the substrate 1 is remarkably increased by an extremely small and compact configuration. Here, the water vapor content of the wet inert gas, that is, the relationship between the humidity and the hydrophilization ability is as shown in FIG. The figure compares the contact angle of the substrate 1 before processing with the contact angle after processing. When the contact angle of the substrate before the treatment was measured, there were some differences depending on the sample, but all of them used a contact angle of 50 degrees or more. As a result of irradiating ultraviolet light having a main wavelength of 172 nm from the discharge lamp 3 under a nitrogen gas atmosphere while changing the humidity for these samples, the humidity was 0%, that is, when irradiating the ultraviolet light with dry nitrogen gas, Although the contact angle is somewhat improved, the degree is small. When the humidity is increased, a significant improvement in the contact angle is recognized. Especially when the humidity is close to 60%, the contact angle is about 6 degrees. Even if the humidity is further increased, the contact angle is substantially reduced. There is no change. Therefore, when the water vapor concentration of the wet nitrogen gas is in the range of 55% to 80%, the contact angle is 6 degrees or less, and desirable results are obtained.

  Thus, by irradiating ultraviolet light from the discharge lamp 3 in the presence of a wet inert gas, the contact angle of the surface 1A to be processed of the substrate 1 is reduced, in other words, the organic on the surface 1A to be processed of the substrate 1 is organic. The removal of dirt is confirmed. Accordingly, when the hydrophilic treatment is intended to clean the substrate 1, inorganic stains are removed by washing with water (shower washing, ultrasonic washing, etc.) before or after the hydrophilic treatment. Thereby, the substrate 1 is cleaned. Further, when the hydrophilic treatment described above is performed as a pretreatment for etching, the developer can be applied uniformly without unevenness, and the etching accuracy is remarkably improved.

1 is a configuration explanatory diagram of a processing apparatus showing an embodiment of the present invention. It is a structure explanatory drawing of the discharge lamp for hydrophilization treatment. It is a diagram which shows the relationship between the humidity of wet inert gas, and the contact angle of the board | substrate by which the hydrophilic treatment was carried out.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Board | substrate 1A Processed surface 2 Conveyance means 3 Discharge lamp 4 Processing chamber 5 Supply piping 6 Punching board 10 Metal electrode 11 Inner tube part 12 Outer tube part 13 Discharge space 14 Ground electrode 15 Protective layer

Claims (7)

A processing region is set in the middle of the transport path for transporting the substrate in a state of being horizontal or inclined with the substrate surface facing upward by the substrate transport means, and this processing region has a predetermined length in the substrate transport direction. A wet inert gas atmosphere is formed by flowing a wet inert gas humidified by water vapor as a downward flow from above, and in the wet inert gas atmosphere, close to the substrate transfer surface constituting the transfer path. Disposing a discharge lamp that irradiates ultraviolet light at a position to perform hydrophilic treatment on the substrate surface,
Replacing the air located on the surface of the substrate with a wet inert gas by introducing the substrate into the processing region;
Irradiating the surface of the substrate with ultraviolet light from the discharge lamp from a close distance in a wet inert gas atmosphere. The discharge lamp irradiates ultraviolet light having a main wavelength of 172 nm, and includes an inner tube portion covering the metal electrode and an outer tube portion provided at a predetermined interval on the inner tube portion, Xenon gas is sealed as a discharge gas between the inner tube and the outer tube, and an earth electrode is provided around the outer tube, and the earth electrode is covered with a ceramic protective layer. The substrate processing method according to claim 1, wherein the substrate is irradiated with ultraviolet light from a distance of 3 mm or less. 2. The substrate processing method according to claim 1, wherein the wet inert gas supplied to the processing region is humidified with water vapor, and the humidity is 55 to 80% nitrogen gas. The substrate processing method according to claim 1, wherein the substrate is a glass substrate for a flat panel display, and the processing is a pretreatment step of applying a developer for dry cleaning or etching. A display device manufactured through the process of claim 4. Substrate transport means for transporting the substrate in a horizontal or inclined state with its processing surface facing upward;
A supply means provided in the middle of the substrate transfer path by the substrate transfer means, and for flowing down the wet inert gas humidified with water vapor toward the substrate transfer means by downflow;
Laminarization means for laminating the wet inert gas supplied from the supply means to flow out over a predetermined length of the substrate transfer path;
An inner tube portion that is disposed in a position close to the substrate transport surface by the substrate transport means and covers a metal electrode in an atmosphere of a wet inert gas formed by the laminarization means, It consists of an outer tube part provided at a predetermined interval in the tube part, and a discharge gas is sealed between the inner tube part and the outer tube part, and a ground electrode is provided around the outer tube part. Further, the ground electrode is composed of a ceramic protective layer formed thereon, and is composed of one or a plurality of discharge lamps that irradiate ultraviolet light toward the substrate surface from a short distance. Processing equipment. Substrate transport means for transporting the substrate in a horizontal or inclined state with its processing surface facing upward;
A supply means provided in the middle of the substrate transfer path by the substrate transfer means, for flowing down the wet inert gas humidified with 55 to 80% of water vapor toward the substrate transfer means by downflow;
Laminarization means for laminating the wet inert gas supplied from the supply means to flow out over a predetermined length of the substrate transfer path;
An inner tube portion that is disposed in a position close to the substrate transport surface by the substrate transport means and covers a metal electrode in an atmosphere of a wet inert gas formed by the laminarization means, It consists of an outer tube part provided at a predetermined interval in the tube part, and a discharge gas is sealed between the inner tube part and the outer tube part, and a ground electrode is provided around the outer tube part. Further, the earth electrode is formed of a ceramic protective layer, and includes one or a plurality of discharge lamps that irradiate ultraviolet light having a main wavelength of 172 nm toward the substrate surface from a distance of 3 mm or less. A substrate processing apparatus characterized by comprising.

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