JP6398839B2 - Light source device - Google Patents

Description

  The present invention relates to a light source device using a short arc flash lamp, and more particularly to a light source device that performs various processes by irradiating a workpiece with vacuum ultraviolet light from a short arc flash lamp as parallel light. is there.

In recent years, vacuum ultraviolet light (hereinafter also referred to as VUV) having a wavelength of 200 nm or less has been used in various fields. For example, a technique for patterning a self-assembled monomolecular film (hereinafter referred to as a SAM film) by causing a chemical reaction with direct light using a VUV and a mask without using a pattern forming process using a photoresist has been developed.
Conventionally, as such a VUV light source, a low-pressure mercury lamp having an emission line at a wavelength of 185 nm has been used. However, recently, it has been said that light with a shorter wavelength, specifically VUV with a wavelength of 180 nm or less, is effective. Therefore, an excimer lamp that emits vacuum ultraviolet light with a wavelength of 172 nm is also used as a light source. . By the way, since the light emitted from these lamps is diverging light, it is not suitable for fine selective surface modification (patterning) using a mask, and there is a limit to the resolvable pattern size. It is said that. More specifically, the line pattern is said to have a limit of about 100 μm.

Recently, development of a light source device suitable for finer patterning has been requested, and for this reason, a light source device using a novel VUV light source has been proposed. For example, Japanese Patent Application Laid-Open No. 2004-235965 ( Patent Document 1) discloses the structure.
The technique described in Patent Document 1 employs a short arc flash lamp having a shorter light emission length as a light source instead of a conventional lamp having a long light emission length (an excimer lamp or a low-pressure mercury lamp). The VUV light emitted from the flash lamp is converted into parallel light (or substantially parallel light) using a mirror to constitute an exposure light source.
Japanese Unexamined Patent Application Publication No. 2014-170921 (Patent Document 2) discloses a light source device using a both-end sealed lamp as a short arc flash lamp.

FIG. 4A shows a schematic structure of the light source device disclosed in Patent Document 1.
4A, in a lamp house 90, a short arc flash lamp 91 that is a VUV light source, and a paraboloid (rotating paraboloid) that emits light emitted from the flash lamp 91 as parallel light in one direction. ) And a light transmission window 93 that transmits VUV is provided below the lamp house 90. The lamp house 90 is filled with an inert gas in order to maintain VUV permeability.
In this prior art, the flash lamp 91 is a single-end sealed lamp, and a pair of electrodes 91b and 91b are disposed opposite to each other inside an arc tube 91a filled with xenon gas or the like. A pair of auxiliary starting electrodes 91c and 91c are disposed between the electrodes.
The flash lamp 91 is arranged so that the opposing axis of the electrodes 91b and 91b is along the optical axis of the reflection mirror 92.

The flash lamp in the light source device of Patent Document 1 is disclosed as a single-end sealed short arc flash lamp. However, a similar light source device using a both-end sealed short arc flash lamp is disclosed. As described above, it is disclosed in Patent Document 2.
A schematic structure of the both-end sealed short arc flash lamp is shown in FIG. 5. A first sealing tube 102 and a second sealing tube 103 are connected to both ends of the arc tube 101. A sealing glass tube 104 is inserted into the second sealing tube 103, and both are welded.
In the arc tube 101, a pair of main electrodes 105, 106 are disposed, and a pair of auxiliary start electrodes 107, 108 are disposed between the main electrodes.
The first sealing tube 102 supports and seals the core wire 105a of the first main electrode 105 and is led out to the outside. On the other hand, the second main electrode 106 has the core wire 106a thereof. It is supported and sealed by the sealing glass tube 104 and led out to the outside.

  The internal leads 107 a and 108 a and the external leads 107 b and 108 b of the pair of auxiliary start electrodes 107 and 108 disposed between the main electrodes 105 and 106 are connected to the second sealing tube 103 and the sealing glass tube 104. In the welding region between them, they are electrically connected via the metal foils 107c and 108c. As a result, the external leads 107b and 108b are led out from between the second sealing tube 103 and the sealing glass tube 104 to the outside.

In the light source device using the short arc flash lamp as described above, as shown in FIG. 4A, the flash lamp is arranged so that the axial direction of the counter main electrode is along the optical axis of the reflecting mirror. The
By the way, when trying to obtain parallel light by such a light source device, since the flash lamp exists in the center of the reflection mirror, the light emitted from the light source device is centered as shown in FIG. The illuminance is lowered at the portion, and a so-called donut-shaped illuminance distribution is formed in which the illuminance of the annular portion surrounding the central portion is increased along the shape of the reflecting surface of the reflecting mirror.
As described above, when the variation in illuminance distribution is large between the central portion of the exposure area and the surrounding annular portion on the irradiation surface of the workpiece, there is a problem that uniform exposure cannot be performed and uneven exposure occurs.

JP 2014-235965 A JP 2014-170921 A

  In view of the above-mentioned problems of the prior art, the problem to be solved by the present invention is that a housing has a pair of main electrodes inside the arc tube and a pair of auxiliary start electrodes disposed between the pair of main electrodes. In a light source device comprising: a short arc flash lamp having a light source; and a reflection mirror that reflects light from the flash lamp as parallel light downward, and a light transmission window is provided below the housing. It is to provide a structure in which light with high illuminance uniformity can be obtained without the light emitted from the light being affected by a flash lamp arranged at the center of the reflecting mirror.

In order to solve the above problems, in the light source device using the short arc flash lamp according to the present invention, the light transmission window is provided in a part of a light shielding plate provided below the housing, and The light transmission window is formed at a position avoiding a position directly below the flash lamp.
In addition, the light transmission window is formed in the light shielding plate at a position avoiding the facing direction of the auxiliary starting electrode.

The flash lamp is a both-end-sealed lamp, and the light transmission window has a wiring direction of a power supply line from the main electrode to an external lead led to the lower side of the reflection mirror in the light shielding plate It is characterized by being formed at a position avoiding the above.
A plurality of the flash lamps are arranged in parallel, and a plurality of paraboloids corresponding to each of the plurality of flash lamps are connected to the reflection mirror, and the light transmission window has a rectangular shape. A plurality of parabolic surfaces of the reflecting mirror are arranged in parallel in the same direction so as to transmit the reflected light.

According to the light source device using the short arc flash lamp of the present invention, the light transmission window is provided at a position avoiding a position directly below the flash lamp in the light shielding plate provided below the housing. The parallel light emitted from the window is not affected by the flash lamp, and parallel light with high illuminance uniformity can be obtained.
The light transmission window is formed in the light shielding plate at a position avoiding the facing direction of the starting auxiliary electrode, so that the light emitted from the flash lamp is not shaded by the starting auxiliary electrode. Irradiance unevenness does not occur in the light emitted from the transmission window.

In the case where the flash lamp is a both-end sealed lamp, the light transmission window has a wiring direction of a power supply line from the main electrode to an external lead led to the lower side of the reflection mirror in the light shielding plate. Since it is formed at a position avoided, the reflected light from the reflecting mirror is not affected by the external lead.
A plurality of the flash lamps are arranged in parallel, a plurality of paraboloid surfaces corresponding to each of the plurality of flash lamps are continuously formed on the reflection mirror, and the light transmission window has a rectangular shape, Since the reflection mirrors are arranged in parallel in the same direction so as to transmit reflected light from a plurality of paraboloids, it is possible to obtain parallel light with a wide irradiation area and high illuminance uniformity.

Sectional drawing (A) (C) and its bottom view (B) (D) of the light source device of this invention. The operation explanatory view of the present invention. Sectional drawing (A) of the Example which has arranged several flash lamps, and its bottom view (B). Conventional light source device. Sectional drawing of the conventional short arc flash lamp of the both ends sealing type.

FIG. 1 shows a light source device using a short arc flash lamp of the present invention, (A) is a sectional view, (B) is a bottom view thereof, and (C) is a sectional view obtained by rotating (A) by 90 °. , (D) is a bottom view thereof.
In the lamp house 1, there are provided a short arc flash lamp 2 which is a VUV light source and a reflection mirror 3 having a rotating paraboloid which reflects light emitted from the flash lamp 2 as parallel light in one direction (downward). It has been.
In this embodiment, the flash lamp 2 is a double-end sealed lamp, and a pair of main electrodes 21 and 22 are provided in the light emitting space of the flash lamp 2. The auxiliary start electrodes 23 and 24 are arranged to face each other.

The flash lamp 2 is arranged such that the opposing direction (electrode axis direction) of the pair of main electrodes 21 and 22 is along the optical axis of the reflection mirror 3, and external leads 25 and 26 is pulled out to the back side (upper side) of the reflection mirror 3, and the power supply line 28 to the external lead 27 of one main electrode 22 located on the front opening side (lower side) of the reflection mirror 3 is connected to the reflection mirror 3. It is pulled out from the opening side (lower side).
A light shielding plate 4 is provided below the lamp house 1, and a light transmission window 5 is formed in a part of the light shielding plate 4 as shown in FIGS.
The light transmission window 5 is provided in the light shielding plate 4 at a position avoiding the direct under of the flash lamp 2, that is, at a part of the annular region from which the direct under of the flash lamp 2 is removed. The opening is formed by fitting a plate-like member having ultraviolet transparency. As the member having ultraviolet transparency, quartz glass (preferably synthetic quartz glass), magnesium fluoride, calcium fluoride and the like are suitable.

Further, as shown in FIGS. 1B and 1D, the light transmission window 5 is preferably provided at a position avoiding the facing direction of the pair of auxiliary starting electrodes 23 and 24.
FIG. 2 shows the relationship, and as shown in FIG. 2B, when the light transmission window 5 is positioned along the opposing direction of the starting auxiliary electrodes 23 and 24, the light from the arc A starts. Under the influence of the auxiliary electrodes 23 and 24, it becomes a shadow S and causes a decrease in illuminance. On the other hand, as shown in FIG. 2A, by providing the light transmission window 5 at a position that avoids the facing direction of the starting auxiliary electrodes 23, 24, the light from the arc A is started. It is no longer affected by the shadow S.

  The light transmission window 5 is provided at a position avoiding the wiring direction of the feeder line 28 connected to the external lead 27 of the main electrode 22 on the lower side (front opening side) of the flash lamp 2. That is, the light transmission window 5 is provided at a position that avoids a position where the reflected light from the reflection mirror 3 is affected by the feeder line 28.

FIG. 3 shows another embodiment. In this embodiment, a plurality of flash lamps 2 and 2 are arranged in parallel. As shown in FIG. 3B, the reflecting mirror 3 is formed with a plurality of reflecting surfaces 31 and 31 corresponding to each of the plurality of lamps 2 and 2. Each of the plurality of reflecting surfaces 31, 31 reflects light from the flash lamps 2, 2 corresponding to the reflecting surfaces 31, 31 downward as parallel light, and is configured by a parabolic surface. Yes.
In the light shielding plate 4, light transmission windows 5, 5 are formed corresponding to the lamps 2, 2 at positions avoiding the positions immediately below the lamps 2, 2. The light transmission window 5 has a rectangular shape, and the light transmission windows 5 and 5 are arranged in parallel along the arrangement direction of the lamps 2 and 2 to form one light transmission window 5 as a whole.
Thereby, a wide light transmission window 5 is formed, and a wide exposure area is obtained.
Also in this case, the light transmission window 5 is provided at a position avoiding the facing direction L of the auxiliary starting electrodes 23 and 24 of the lamp 2, for example, at a perpendicular position. Further, the feeder lines 28 and 28 are also drawn out in a direction different from the light transmission windows 5 and 5.

As described above, in the light source device using the short arc flash lamp according to the present invention, the light transmission window is provided in a part of the light shielding plate provided below the reflection mirror in the housing, and Since it is provided at a position avoiding the position directly below the flash lamp, the emitted light from the light transmission window that transmits the reflected light from the reflecting mirror is not affected by the installation position of the flash lamp, and the illuminance uniformity High light can be obtained.
In particular, when the light source device emits VUV, if an optical element such as a lens is used between the reflection mirror and the object to be processed, the light is absorbed or attenuated by the optical element, thereby reducing the light use efficiency. However, according to the light source device of the present invention, since it is configured to directly extract without interposing an optical element, uniform VUV can be emitted with high efficiency.

DESCRIPTION OF SYMBOLS 1 Housing 2 Short arc flash lamp 21, 22 Main electrode 23, 24 Starting auxiliary electrode 26, 26 External lead (of starting auxiliary electrode) 27 External lead (of main electrode) 28 Feed line 3 Reflecting mirror 31 Reflecting surface 4 Light shielding plate A Arc S The shade of the auxiliary starting electrode

Claims (4)

A short arc flash lamp having a pair of main electrodes inside the arc tube and a pair of auxiliary start electrodes disposed between the pair of main electrodes, and light from the flash lamp as parallel light downwards In the light source device having a reflection mirror that reflects, and provided with a light transmission window below the housing,
The light transmission window is provided at a part of a light shielding plate provided below the housing, and the light transmission window is formed at a position avoiding a position directly below the flash lamp. Light source device.   2. The light source device according to claim 1, wherein the light transmission window is formed at a position in the light shielding plate so as to avoid a facing direction of the auxiliary starting electrode. The flash lamp is a both-end sealed lamp,
The light transmission window is formed in the light shielding plate at a position avoiding a wiring direction of a power supply line from the main electrode to an external lead led to the lower side of the reflection mirror. 3. The light source device according to 1 or 2. A plurality of the flash lamps are arranged in parallel,
In the reflection mirror, a plurality of reflection surfaces corresponding to each of the plurality of flash lamps are continuously formed,
The said light transmission window is a rectangular shape, It arrange | positions in parallel in the same direction so that the reflected light from the several reflective surface of the said reflective mirror may be permeate | transmitted. Light source device.

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