JP2015069734A - Excimer lamp device and irradiation processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an excimer lamp device configured so that an excimer lamp is enclosed in a protective tube, and a vacuum ultraviolet ray radiated from the excimer lamp is prevented from being emitted from a part other than the light transmission part of the protective tube, and to provide a light irradiation processing apparatus in which generation of ozone in the outside of a workpiece processing space is prevented reliably.SOLUTION: An excimer lamp device is configured so that an excimer lamp radiating vacuum ultraviolet ray is enclosed in a protective tube having a light transmission part formed of synthetic quartz glass surrounding the radiation region of the excimer lamp, and a non-light transmission part formed of molten quartz glass. A light irradiation processing apparatus includes a housing having a processing chamber formed by sectioning the internal space by the partition wall. The excimer lamp device is configured such that the non-light transmission part is arranged while being fixed airtightly to the partition wall, in a state where the light transmission part in the protective tube is located in the processing chamber.

Description

  The present invention relates to an excimer lamp device and a light irradiation processing device.

  For example, in sample observation with an electron microscope, if contaminants such as hydrocarbons adhere to the surface of the sample, there is a risk of sample contamination that obstructs observation or analysis. It has been done to remove.

Conventionally, in removing contaminants adhering to a sample, for example, by irradiating the sample with vacuum ultraviolet light having a wavelength of 200 nm or less, the action of the vacuum ultraviolet light and the generated active oxygen or ozone is used. The photo-cleaning treatment technology is used. For example, a low-pressure mercury lamp has been used as a light source used in such a light cleaning process.
However, in order to remove hydrocarbons efficiently, it is desirable to use vacuum ultraviolet light having a wavelength of 204 nm or less, for example. In recent years, an optical cleaning technique using an excimer lamp has been put into practical use.

  For example, in Japanese Patent Application Laid-Open No. 2006-164893 of Patent Document 1, in a charged particle beam apparatus, the sample is attached to the sample by irradiating the sample with vacuum ultraviolet light having a wavelength of 172 nm before and after observation of the sample with the charged particle beam. Contamination and techniques for removing hydrocarbons that cause contamination are described.

JP 2006-164893 A

Thus, in the ultraviolet irradiation unit in Patent Document 1, as shown in FIG. 3, the excimer lamp 70 is disposed in a space in which the sample S is disposed and a space that is airtightly partitioned by the quartz window member 75. It is configured. However, in such a configuration, since it is necessary to form an airtight space for excimer lamp arrangement, there is a problem that the structure of the ultraviolet irradiation unit itself becomes complicated.
On the other hand, when the excimer lamp has a configuration in which the excimer lamp is simply arranged in the processing space of the object to be processed without forming an airtight space, the pair of external leads connected to each of the electrodes of the excimer lamp is in a vacuum atmosphere or a reduced pressure. It will be exposed to the atmosphere, and there is a problem that discharge occurs between the external leads.

  In order to solve such a problem, it can be considered that the excimer lamp has a structure in which the arc tube is held by a partition wall that partitions the processing space of the object to be processed. However, in such a configuration, a part of the arc tube is exposed to the outside of the processing space, so that vacuum ultraviolet rays from the excimer lamp are also irradiated to the outside of the processing space. Ozone is generated outside, and as a result, it may adversely affect peripheral devices and processing steps. In addition, ozone is harmful to the human body and has a problem that it may adversely affect workers. Furthermore, the operator is exposed to the danger of the high-pressure side electrode in the excimer lamp. In order to avoid danger to the electrode on the high voltage side, for example, a protective tube made of synthetic quartz glass may be provided so as to cover the arc tube, but ozone is generated outside the processing space. The problem is not solved.

The present invention has been made on the basis of the above circumstances, and an object of the present invention is to have a configuration in which an excimer lamp is enclosed in a protective tube, and vacuum ultraviolet rays radiated from the excimer lamp are protected by the protective tube. Another object of the present invention is to provide an excimer lamp device that can prevent the light from being emitted from a portion other than the light transmitting portion.
Another object of the present invention is to provide a light irradiation processing apparatus for removing contaminants on the surface of an object to be processed by applying an ultraviolet ray from an excimer lamp apparatus outside the processing space for the object to be processed. It is in providing the light irradiation processing apparatus which can prevent reliably producing | generating.

The excimer lamp device of the present invention comprises an excimer lamp that radiates vacuum ultraviolet rays, and a protective tube that encloses the excimer lamp inside.
The protective tube has a light transmission part made of synthetic quartz glass surrounding a discharge area of the excimer lamp and a non-light transmission part made of fused silica glass.

The light irradiation processing apparatus of the present invention includes a housing having a processing chamber composed of a sealed space formed by dividing an internal space by partition walls,
The excimer lamp device is characterized in that the non-light transmissive portion in the protective tube is hermetically fixed to the partition wall in a state where the light transmissive portion in the protective tube is positioned in the processing chamber. And

According to the excimer lamp device of the present invention, the fused silica glass constituting the non-light transmitting portion of the protective tube is difficult to transmit vacuum ultraviolet rays (wavelength of 200 nm or less). The vacuum ultraviolet rays radiated in the partial direction are absorbed and shielded by the non-light transmitting portion of the protective tube. Therefore, it is possible to reliably prevent the vacuum ultraviolet rays radiated from the excimer lamp from being emitted from places other than the light transmitting portion of the protective tube.
Therefore, the above-described excimer lamp device is a light irradiation processing apparatus according to the present invention in which the light transmitting portion in the protective tube is positioned in the processing chamber and the non-light transmitting portion is hermetically fixed to the partition wall that partitions the processing chamber. According to the present invention, the intended light irradiation treatment (removal of hydrocarbons, etc.) can be performed on the object to be processed disposed in the processing chamber by the vacuum ultraviolet ray emitted from the light transmitting portion in the protective tube, It is possible to avoid generation of ozone by emitting vacuum ultraviolet rays to a space outside the processing chamber, which is normally an atmospheric atmosphere.

It is a fragmentary sectional view showing the outline of the composition in an example of the excimer lamp device of the present invention in the state where a part was cut in the section along the axial direction. It is sectional drawing which shows the outline of a structure in an example of the light irradiation processing apparatus of this invention. It is sectional drawing which shows the outline of a structure in an example of the conventional ultraviolet irradiation unit.

Hereinafter, embodiments of the present invention will be described in detail.
FIG. 1 is a partial cross-sectional view showing a schematic configuration of an example of an excimer lamp device according to the present invention in a state where a part thereof is cut along a cross section along an axial direction.
The excimer lamp device 10 includes an excimer lamp 11 that radiates vacuum ultraviolet rays, and a protective tube 30 that encloses the excimer lamp 11 therein.

  The excimer lamp 11 includes an arc tube 12 having a tubular light-emitting portion 13 and sealing portions 14 a and 14 b provided continuously at both ends of the light-emitting portion 13. In this example, one sealing portion 14a in the arc tube 12 has a cylindrical shape formed by a shrink seal method, and the other sealing portion 14b is a flat shape formed by a pinch seal method. It has a shape. The arc tube 12 is made of, for example, synthetic quartz glass.

  Inside the arc tube 12, an internal electrode 20 in which a metal wire is wound in a coil shape is arranged along the central axis A of the arc tube with the coil axis coinciding with the central axis A of the arc tube 12. It is arranged to extend. The internal electrode 20 has an internal electrode external lead 22 that protrudes outward in the axial direction from the outer end of the one sealing portion 14a through a metal foil 21 that is airtightly embedded in the one sealing portion 14a. Is electrically connected. The other end portion of the internal electrode 20 is supported by the other sealing portion 14b.

The arc tube 12 is filled with a luminescent gas. As the luminescent gas, for example, a rare gas having an action as a discharge medium for forming excimer molecules by excimer discharge such as xenon gas (Xe), argon gas (Ar), krypton gas (Kr), or the like is used.
The arc tube 12 is filled with halogen gas such as fluorine gas (F), chlorine gas (Cl), iodine gas (I), and bromine gas (Br) as required along with the rare gas.

  An external electrode 25 is disposed on the outer surface of the arc tube 12 so as to extend along the axial direction. The external electrode 25 in this example is a net-like shape having a cylindrical shape, and is provided in close contact with the outer surface of the light emitting unit 13 over the entire outer peripheral surface of the light emitting unit 13.

The protective tube 30 has a bottomed cylindrical shape with one end opened, and the opening is hermetically sealed by a substantially columnar sealing member 35. The sealing member 35 is made of, for example, fused silica glass, is inserted and disposed in the opening of the protective tube 30, and the outer peripheral surface thereof and the inner peripheral surface of the protective tube 30 are welded.
The inner space of the protective tube 30 is filled with an inert gas such as nitrogen gas.

  One end portion of one sealing portion 14 a of the excimer lamp 11 is fixed to the other end portion of the sealing member 35, and the excimer lamp 11 does not contact the inner peripheral surface of the protective tube 30. The central axis A is held while being positioned on the central axis of the protective tube 30. The internal electrode external lead 22 in the excimer lamp 11 extends through the central position of the sealing member 35 in an airtight manner in the axial direction, and one end portion thereof is led out to the outside.

A metal foil 40 made of, for example, molybdenum is embedded in an airtight manner at a joint portion between the outer peripheral surface of the sealing member 35 and the inner peripheral surface of the protective tube 30. One end of a rod-like internal lead 42 connected to the external electrode 25 of the excimer lamp 11 is connected to the metal foil 40 via a feeder line 41 made of a stranded wire, and one end is a protective tube 30. The other end of the rod-like external electrode external lead 43 that protrudes outward in the axial direction from one end face is connected. The internal lead 42 is made of, for example, molybdenum, and the power supply line 41 is made of, for example, a nickel wire.
By having such a configuration, it is possible to sufficiently secure the size of the space distance between the external electrode external lead 43 and the internal electrode external lead 22, while maintaining the electrical insulation state, A desired power feeding structure can be formed. Further, since the power supply line 41 made of a stranded wire is used, a large force is not applied to the sealing portion by the internal lead 42 or the sealing member 35, and the external electrode 25 and the external of the power supply line 41 are not applied. A sufficiently large contact area with respect to the electrode external lead 43 can be secured, and also in this respect, the intended power supply structure can be reliably formed.

  A base member 45 is fixed to one end of the protective tube 30 with an inorganic adhesive, and one end of each of the external electrode external lead 43 and the internal electrode external lead 22 is provided on the base member 45. It is connected to feeder lines 46 and 46.

As described above, the protective tube 30 in the excimer lamp device 10 includes the light transmitting portion 31 that emits vacuum ultraviolet rays emitted from the excimer lamp 11 and the non-light transmitting portion 32 that blocks vacuum ultraviolet rays.
Specifically, the region surrounding the discharge region L of the excimer lamp 11 in which the internal electrode 20 and the external electrode 25 are arranged to face each other in the protective tube 30 is made of synthetic quartz glass. A transmission part 31 is formed. In addition, a region continuing to the light transmission portion 31 and located on the outer side in the axial direction of the discharge region L of the excimer lamp 11 is made of fused silica glass, whereby vacuum ultraviolet rays are absorbed by the fused silica glass. Thus, a non-light transmission portion 32 that is shielded is formed.

  The non-light transmission part 32 in the protective tube 30 has a larger thickness than the light transmission part 31. With such a configuration, as will be described later, a sufficiently high strength can be obtained in the non-light transmitting portion 32 that is a fixed portion, and an intended ultraviolet ray absorbability can be reliably obtained.

  Such a protective tube 30 can be manufactured by melt-bonding a light transmitting part forming material made of synthetic quartz glass and a non-light transmitting part forming material made of fused silica glass.

  Thus, according to the excimer lamp device 10 having the above-described configuration, the fused silica glass constituting the non-light transmitting portion 32 in the protective tube 30 is difficult to transmit vacuum ultraviolet rays (with a wavelength of 200 nm or less). The vacuum ultraviolet rays from 11 toward the non-light transmitting portion 32 of the protective tube 30 are absorbed by the non-light transmitting portion 32 of the protective tube 30. Therefore, it is possible to reliably prevent the vacuum ultraviolet rays radiated from the excimer lamp 11 from being emitted from a portion other than the light transmission portion 31 of the protective tube 30.

[Light irradiation treatment equipment]
The light irradiation treatment apparatus of the present invention is for removing contaminants such as hydrocarbon adhering to the surface of a sample for an electron microscope, for example.
FIG. 2 is a cross-sectional view schematically showing the configuration of an example of the light irradiation processing apparatus of the present invention.
This light irradiation processing apparatus includes a casing 50 having a processing chamber C formed of a sealed space whose inner space is defined by a partition wall 51, and an object to be processed W is placed in the processing chamber C. A mounting table 55 is provided. The casing 50 is provided with, for example, an inert gas purge means (not shown) for purging an inert gas of nitrogen gas into the processing chamber C, and a decompression means (not shown) for reducing the pressure inside the processing chamber C. Is provided. Here, the pressure in the processing chamber C is, for example, 10 ⁻¹ to 10 ⁻⁴ Pa.

  In this light irradiation processing apparatus, the excimer lamp device 10 shown in FIG. 1 has the non-light transmitting portion 32 in the protective tube 30 fixed while the light transmitting portion 31 in the protective tube 30 is positioned in the processing chamber C. It is made into a part and is airtightly fixed to the partition wall 51 and arranged. Specifically, the protective tube in the excimer lamp device 10 in a state where the light transmitting portion 31 of the protective tube 30 in the excimer lamp device 10 is inserted into the processing chamber C through the opening 52 formed in the partition wall 51. The flange member 60 provided on the outer peripheral surface of the 30 non-light transmitting portion 32 is fixed to the partition wall 51. The excimer lamp device 10 is arranged such that the central axis (the central axis A of the arc tube) of the excimer lamp 11 extends along the workpiece mounting surface 55a of the mounting table 55, and the light transmitting portion in the protective tube 30 31 opposes the workpiece W mounted on the mounting table 55. The flange member 60 is attached to the outer peripheral surface of the protective tube 30 with a seal member 61 such as an O-ring interposed, for example. Further, the flange member 60 may be fixed to the protective tube 30 in the excimer lamp device 10 with an adhesive. Since the flange member 60 may be exposed to the atmosphere in the processing chamber C, it is preferable to use, for example, glass as the material constituting the flange member 60 in order to prevent the occurrence of contamination.

  In the light irradiation processing apparatus having the above-described configuration, the atmosphere in the processing chamber C is changed to the inert gas atmosphere by operating the decompression unit and the inert gas purge unit while the workpiece W is set on the mounting table 55. And a predetermined reduced pressure state. In this state, when high frequency AC power is supplied from the high frequency AC power source to the internal electrode 20 of the excimer lamp 11 via the internal electrode external lead 22 and the metal foil 21, excimer discharge occurs in the internal space of the arc tube 12. As a result, excimer molecules are formed and excimer light (for example, vacuum ultraviolet light having a wavelength of 172 nm in the case of xenon gas) is emitted from the excimer molecules. The vacuum ultraviolet rays radiated from the excimer lamp 11 pass through the light transmitting portion 31 in the protective tube 30 and are irradiated on the entire surface to be processed of the object to be processed W, and thereby adhere to the surface of the object to be processed W, for example. The removal processing (cleaning processing) of contaminants, such as the done hydrocarbon, is made.

Thus, according to the above-described light irradiation processing apparatus, the above-described excimer lamp apparatus 10 has the partition wall 51 in which the non-light transmitting portion 32 made of fused silica glass having the characteristic of absorbing vacuum ultraviolet rays partitions the processing chamber C. Therefore, it is possible to reliably prevent vacuum ultraviolet rays from being emitted to the space outside the processing chamber C while reliably forming a sealed (airtight) structure of the processing chamber C. Can do. Therefore, the intended light irradiation process (removal of hydrocarbon, etc.) can be performed on the workpiece W by the vacuum ultraviolet rays emitted from the light transmitting portion 31 of the protective tube 30 located in the processing chamber C. In addition, it is possible to avoid the generation of ozone due to the emission of vacuum ultraviolet rays into the space outside the processing chamber C, which is normally an atmospheric atmosphere.
In addition, since the constituent members exposed to the atmosphere in the processing chamber C are only those made of glass materials (synthetic quartz glass and fused silica glass), it is possible to reliably prevent contamination from occurring on the workpiece. Can do.

  As mentioned above, although one embodiment of the excimer lamp device of the present invention has been described, the present invention is not limited to the above embodiment, and various modifications can be made.

DESCRIPTION OF SYMBOLS 10 Excimer lamp apparatus 11 Excimer lamp 12 Light emission tube 13 Light emission part 14a One sealing part 14b The other sealing part 20 Internal electrode 21 Metal foil 22 External lead for internal electrodes 25 External electrode 30 Protection tube 31 Light transmission part 32 Non-light Transmission part 35 Sealing member 40 Metal foil 41 Feed line 42 Internal lead 43 External lead for external electrode 45 Base member 46 Feed line A Central axis of arc tube (lamp central axis)
L discharge area 50 casing 51 partition wall 52 opening 55 mounting table 55a workpiece mounting surface 60 flange member 61 seal member C processing chamber W workpiece 70 excimer lamp 75 quartz window member S sample

Claims (2)

An excimer lamp that radiates vacuum ultraviolet rays, and a protective tube that encloses the excimer lamp inside,
The excimer lamp device characterized in that the protective tube has a light transmission part formed of synthetic quartz glass surrounding a discharge region of the excimer lamp and a non-light transmission part formed of fused silica glass. . It has a housing having a processing chamber consisting of a sealed space formed by partitioning an internal space with a partition wall;
The excimer lamp device according to claim 1, wherein the non-light transmitting portion of the protective tube is hermetically fixed to the partition wall in a state where the light transmitting portion of the protective tube is positioned in the processing chamber. A light irradiation treatment apparatus characterized by comprising:

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