JP2018155982A - Light irradiation device and exposure device therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exposure device with short arc flash lamp, which uses a short arc flash lamp that radiates vacuum violet light in a lens tube and has high light utilization efficiency and improved illumination uniformity.SOLUTION: In a lens tube 2, an optical system 5 that makes reflected light from a condensation mirror 4 parallel to homogenize illuminance, the optical system is formed of a plurality of lens members 51 to 55 linearly arranged along the same optical axis between a lamp 3 and a light irradiation window 6, the lens tube is formed of a plurality of lens tube units 20 to 25, each of the lens tube units holds the lamp and a plurality of lens members, on the upper side of a position where the lamp of the lens tube is arranged an inert gas feed port 32 is provided, and on a lower end surface of the lens tube an inert gas discharge port 62 is provided to replace the inside of the lens tube with the inert gas.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a light irradiation apparatus using a short arc flash lamp and an exposure apparatus equipped with the same, and in particular, various kinds of processing by irradiating a workpiece with vacuum ultraviolet light from a short arc flash lamp as parallel light. The present invention relates to a light irradiation apparatus that performs the above and an exposure apparatus including the same.

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. There is no LED that can emit light in this wavelength band, and a discharge lamp is used as a light source. 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 irradiation device using a novel VUV light source has been proposed. For example, Japanese Patent Application Laid-Open No. 2006-192343 has been proposed. (Patent Document 1) discloses the structure.
FIG. 8 shows a schematic structure thereof. A short arc flash lamp 102 and a reflecting mirror 103 are arranged in the housing 101 so that light is irradiated downward, and a light transmission window 104 is provided below. The interior of the housing is filled with nitrogen.
No member is disposed between the reflecting mirror 103 and the light transmission window 104, and the light exhibits a donut-shaped (annular) distribution on the window surface. Therefore, the aperture 105 is only in a part where the illuminance is high and uniform. Is to arrange.

  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) by using a reflection mirror to constitute a light irradiation device as a light source for exposure.

According to this prior art, a parabolic mirror is attached to the lamp as a reflecting mirror, and parallel light is formed without an optical system such as a lens. However, since only a part of the light emitted in a donut shape is used, the light use efficiency is low. Also, the illuminance uniformity on the irradiated surface was not high.
In view of this, the present inventors have examined the arrangement of an optical component such as a lens between a light source (lamp) and an aperture in order to improve light utilization efficiency and illuminance uniformity.
However, in order to propagate light of 200 nm or less, there is a situation that light is significantly attenuated when oxygen is present in the propagation space.
For example, it is preferable that 10 ppm or more of oxygen is not present in the light propagation space, and the optical component preferably has a high transmittance for light with a wavelength of 200 nm or less. Furthermore, it is preferable not to arrange the folding mirror in which optical loss occurs in the optical system.

JP, 2006-192343, A

  In view of the above-mentioned problems of the prior art, the problems to be solved by the present invention are a short arc flash lamp that emits vacuum ultraviolet light having a wavelength of 200 nm or less in a lens barrel, and a condenser mirror that reflects light from the lamp. In the light irradiation apparatus having a light irradiation window at the lower part of the lens barrel and the exposure apparatus having the light irradiation window, all the light from the condenser mirror is emitted from the light irradiation window, and the light use efficiency Is to provide a structure having high illuminance uniformity.

In order to solve the above-described problems, a light irradiation apparatus using a short arc flash lamp according to the present invention includes an optical system in a lens barrel that collimates the light reflected by the condenser mirror and uniformizes illuminance. The optical system includes a plurality of lens members arranged linearly along the same optical axis between the lamp and the light irradiation window, and the lens barrel includes a plurality of lens barrel units. The tube unit holds the lamp and the plurality of lens members, respectively, and an inert gas supply port is provided above the position of the lamp in the lens barrel, and an inert gas is provided on the lower end surface of the lens barrel. A gas discharge port is provided, and the inside of the lens barrel is replaced with an inert gas.
The lens barrel unit includes a lamp barrel unit and a lens barrel unit. The lens barrel unit is provided with a lens member holding portion, and the lens member holding portion is provided on the upper surface side of the lens member. Ventilation holes for flowing an inert gas to the lower surface side are formed.
In addition, a wind direction plate that changes the outflow direction of the inert gas from the vent toward the lower surface of the lens member is provided below the vent.

An exposure apparatus including the light irradiation apparatus includes a mask stage disposed below the light irradiation apparatus and a work stage disposed below the mask stage.
In addition, a covering member that covers an upper portion of the mask stage is provided below the light irradiation device.

  According to the light irradiation apparatus using the short arc flash lamp of the present invention, in the light irradiation apparatus including a lamp and a condensing mirror in a lens barrel, and having a light irradiation window below the lens barrel, the mirror An optical system for collimating the light reflected by the condenser mirror and making the illuminance uniform is provided in the cylinder, and the optical system is linear along the same optical axis between the lamp and the light irradiation window. Since the light emitted from the lamp and reflected by the condensing mirror is made parallel by the optical system and the illuminance is made uniform, all of it is emitted from the light irradiation window. The light use efficiency is extremely high and the illuminance uniformity is improved.

In addition, the lens barrel includes a plurality of lens barrel units that respectively hold the lamp and the plurality of lens members, so that the structure thereof is simplified, and the entire lens barrel can be easily assembled by assembling these lens barrel units. Can be manufactured.
In addition, by providing an inert gas supply port at the top of the lens barrel and a discharge port at the bottom, the entire interior of the lens barrel can be easily replaced with inert gas, and vacuum ultraviolet light (VUV) Attenuation can be suppressed.
Further, by forming a vent in the lens member holding portion provided in each lens barrel, an inert gas atmosphere can be easily formed over the entire barrel.
In addition, the atmosphere on the lower surface side of each lens is stagnant and it is difficult to replace it with an inert gas. However, by providing a wind direction plate and directing the inert gas from the vent to the lower surface of the lens, the inert gas is effectively removed Can be substituted.

Sectional drawing of the light irradiation apparatus of this invention. Sectional drawing of the short arc type flash lamp used for this invention. The expanded sectional view of the upper part of the lens-barrel of this invention. The expanded sectional view of the center part of the lens-barrel of this invention. The expanded sectional view (A) of the lower part of the lens-barrel of this invention, its bottom view (B). An exposure apparatus provided with the light irradiation apparatus of the present invention. The elements on larger scale of FIG. Conventional light irradiation device.

FIG. 1 shows the whole light irradiation apparatus using the short arc flash lamp of the present invention, and FIGS. 3 to 5 are partial enlarged views thereof.
In FIG. 1, a light irradiation apparatus 1 according to the present invention is provided at a lens barrel 2, a short arc flash lamp 3 provided therein, a condensing mirror 4 surrounding the same, an optical system 5, and a lowermost part. The light irradiation window 6 is provided.
The lens barrel 2 includes a plurality of lens barrel units 20 to 25, and each lens barrel unit holds a lamp 3 and a plurality of lens members 51 to 55 constituting an optical system 5.
The optical system 5 is for collimating the light emitted from the lamp 3 and reflected by the condenser mirror 4 to make the illuminance uniform, and includes, for example, a first lens member (biconcave lens) 51, The second lens member (plano-convex lens) 52, the third lens member (integrator lens) 53, the fourth lens member (convex meniscus lens) 54, and the fifth lens member (biconvex lens) 55.

The lamp barrel unit 20 located at the top holds the lamp 3 and the condenser mirror 4. The lamp 3 used here is a short arc flash lamp, and its schematic structure is shown in FIG.
The short arc type flash lamp 3 includes a light emitting tube 301 that forms a light emitting space, a first sealing tube 302 that extends outward along the tube axis direction continuously to one end of the light emitting tube 301, and a second end. A second sealing tube 303 continuously extending outward along the tube axis direction is provided, and a sealing glass tube 304 is inserted into the second sealing tube 303, and in the overlapping region Both are welded.

  In the arc tube 301, a pair of first main electrode 305 and second main electrode 306 are disposed to face each other. The first main electrode 305 has its core wire 307 sealed to the first sealing tube 302 by means such as step glass, and is led out in an airtight manner. On the other hand, the second main electrode 306 is The core wire 308 is sealed to the sealing glass tube 304 by means such as step glass, and is led out in an airtight manner.

  Between the pair of main electrodes 305 and 306 in the arc tube 301, a pair of first start-up auxiliary electrode 310 and second start-up auxiliary electrode 311 are disposed. External leads 313 and 316 are electrically connected via metal foils 314 and 317 in the welding region between the second sealing tube 303 and the sealing glass tube 304.

A base 320 made of aluminum or the like is fixed to the second sealing tube 303 on the side from which the external leads 313 and 316 are led out of the auxiliary starting electrodes 310 and 311. The space between the base 320 and the second sealing tube 303 is filled with the first adhesive 321, and the space between the base 320 and the sealing glass tube 304 is interposed via the partition member 323. Is filled with a second adhesive 322.
External leads 313 and 316 led out from the second sealing tube 303 are embedded in the second adhesive 322 and led out from the rear of the base 320. The external leads 313 and 316 are covered with insulating coating materials 313a and 316a at the rear portions thereof.
The details of such a short arc flash lamp 3 are disclosed in JP-A-2006-131135.

  The lens barrel 2 has an elongated cylindrical shape, and is constituted by a cylindrical member obtained by cutting aluminum, for example. The lens barrel 2 includes a plurality of lens barrel units 20 to 25, and the lens barrel unit positioned at the uppermost part constitutes a lamp lens barrel unit 20 that houses and holds the lamp 3 therein. A condenser mirror 4 is provided in the lamp barrel unit 20 so as to surround the lamp 3, and the condenser mirror 4 is, for example, an elliptical condenser mirror.

As shown in FIG. 3, the base 320 of the lamp 3 is held on the upper part of the lamp barrel unit 20 by a lamp holding member 31, and the lamp holding member 31 has an inert gas that opens in the barrel 2. A supply port 32 is formed, and an inert gas supply pipe 33 is connected.
An inert gas such as nitrogen gas supplied from the inert gas supply port 32 into the lamp barrel unit 20 flows down along the lamp from the gap between the condenser mirror 4 and the lamp 3 to cool the lamp 3. Then, it flows downward.

Referring to FIG. 1 again, a plurality of lens barrel units 21 to 25 are provided below the lamp barrel unit 20, and these lens barrel units 21 to 25 are emitted from the lamp 3. The plurality of lens members 51 to 55 constituting the optical system 5 that collimates the light reflected by the condenser mirror 4 and equalizes the illuminance are respectively held.
In other words, the first lens barrel unit 21 has a first lens member (bi-concave lens) 51, the second lens barrel unit 22 has a second lens member (plano-convex lens) 52, and a third lens. The lens barrel unit 23 has a third lens member (integrator lens) 53, the fourth lens barrel unit 24 has a fourth lens member (convex meniscus lens) 54, and a fifth lens barrel unit. A fifth lens member (biconvex lens) 55 is held at 25.
A light irradiation window 6 is provided at the lower end of the fifth lens barrel unit 25 located at the bottom.
The selection and combination of the first to fifth lenses can be appropriately selected according to the target parallelism and illuminance uniformity.

  In this way, the lens barrel 2 is configured by combining the lamp barrel unit 20 and the plurality of lens barrel units 21 to 25, and the first to fifth lens members 51 to 55 provided therein are An optical system 5 arranged linearly along the same optical axis OA between the light irradiation windows 6 is configured.

As shown in FIGS. 4 and 5, the lens holding units 211 to 251 are formed in the lens barrel units 21 to 25, and hold the first to fifth lens members 51 to 55, respectively. . This lens holding part can be constituted by a flange part protruding inward as a step part by cutting the lens barrel unit.
The lens holding portions 211 to 251 are formed with vent holes 212 to 252 penetrating them in the optical axis direction, respectively, so that the space on the upper surface side and the lower surface side of each lens member 51 to 55 is communicated. Yes.

Further, as shown in FIG. 4, for example, a wind direction plate 223 is provided below the vent hole 222 of the lens holding portion 221 in the second lens barrel unit 22, and the inert gas ejected from the vent hole 222 is provided. The gas is directed toward the lower surface side of the second lens member 52.
Thereby, at the time of replacement with the inert gas, the lower surface side of the lens member 52 that is difficult to be replaced due to the flow of air that is stagnated and effectively replaced is replaced with the inert gas.
The wind direction plate may be provided not only in the second lens barrel unit 22 but also in all the lens barrel units 21 to 25.

And as shown to FIG. 5 (A) (B), in the flange area | region 61 other than the light extraction part in the light irradiation window 6 provided in the lower end of the 5th lens barrel unit 25 located in the lowest step, An inert gas discharge port 62 is formed, and the inert gas supplied into the lens barrel 2 from the inert gas supply port 32 flows downward in the lens barrel 2 to pass through the inside of the lens barrel 2. After making the atmosphere, it is ejected from the inert gas outlet 62 to the outside of the lens barrel 2.
As described above, the flow rate of the inert gas (nitrogen gas) that suppresses the oxygen concentration in the lens barrel 2 to, for example, 10 ppm (volume ratio) or less while cooling the lamp is, for example, 25 L (liter) / min.

Further, the lens members 51 to 55 constituting the optical system 5 and the light irradiation window 6 are made of, for example, a material that transmits light of 200 nm or less in order to efficiently use vacuum ultraviolet light.
More preferably, it is made of a material having a transmittance of light having a wavelength of 200 nm of 80% or more. Specifically, it is fluoride that has those properties, and more specifically, for example, calcium fluoride (CaF ₂ ), magnesium fluoride (MgF ₂ ), and barium fluoride (BaF ₂ ).

  In the above embodiment, each lens barrel unit has been described as having one lamp and one lens, but a plurality of these may be provided in one lens barrel. For example, the lamp 3 and the first lens member 51 are provided in the first lens barrel unit 21, or the first lens member 51 and the second lens member 52 are provided in the second lens barrel unit 22. It is good also as a structure.

6 and 7 show examples of an exposure apparatus using the light irradiation apparatus of the present invention.
As shown in FIG. 6, in the light irradiation device 1, the lens barrel is held by a gantry 11 provided on the basis of a frame such as an optical bench (not shown) and is maintained in the air. A work stage 12 is provided on the surface plate 10 so as to be movable in the horizontal direction (XY direction). A workpiece W is placed and supported on the upper surface of the workpiece stage 12, and a θ rotation mechanism is provided to allow the workpiece W to rotate.
On the other hand, the mask 14 is supported by vacuum suction by the mask stage 13 and is movable in the XY directions. At this time, the work W includes not only the substrate but also a belt-like work and the like and cannot be brought into close contact with the mask 14, so that the work W and the mask 14 are arranged as close as possible.

The light irradiation window at the lower end of the light irradiation apparatus 1 is also arranged close to the mask 14, but there is always a certain gap.
Since the light irradiation apparatus 1 of the present invention uses vacuum ultraviolet light of 200 nm or less, absorption occurs due to oxygen present in the gap between the light irradiation window and the mask. In order to suppress this absorption, A coating member 7 made of a plate material or a block material is provided at the lower end of the irradiation apparatus 1 and is arranged close to cover the mask 14 and the mask stage 13.
As shown in FIG. 7, the covering member 7 causes an inert gas ejected from the light irradiation window to flow along the mask 14, thereby effectively purging oxygen in the gap between the light irradiation window and the mask. It is something that can be done.

As described above, in the light irradiation apparatus using the short arc flash lamp according to the present invention, the light irradiation includes a lamp and a condensing mirror in a lens barrel, and a light irradiation window in the lower part of the lens barrel. In the apparatus, an optical system for collimating the light reflected by the condenser mirror and making the illuminance uniform is provided in the lens barrel, and the optical system is on the same optical axis between the lamp and the light irradiation window. Since the light emitted from the lamp and reflected by the condenser mirror is made parallel by the optical system and the illuminance is made uniform, all of which is a light irradiation window. Since the light is emitted from the light, the light utilization efficiency is extremely high and the illuminance uniformity is improved.
In addition, since the lens barrel includes a plurality of lens barrel units, and each lens barrel unit holds the lamp and the plurality of lens members, respectively, the entire structure of the lens barrel is simplified. By assembling the unit, the entire lens barrel can be easily manufactured.

DESCRIPTION OF SYMBOLS 1 Light irradiation apparatus 2 Lens barrel 20 Lamp barrel unit 21-25 1st-5th lens barrel unit 211-251 Lens holding part 212-252 Vent 3 Short arc flash lamp 32 Inert gas supply port 4 Condensing Mirror 5 Optical system 51-55 First to fifth lens members 6 Light irradiation window 62 Inert gas discharge port 7 Cover member 12 Work stage 13 Mask stage 14 Mask W Work

Claims (5)

A light irradiating apparatus comprising a short arc flash lamp that emits vacuum ultraviolet light having a wavelength of 200 nm or less and a condensing mirror that reflects light from the lamp in a lens barrel, and a light irradiation window provided at a lower portion of the lens barrel Because
The lens barrel includes an optical system that collimates the light reflected by the condenser mirror and uniformizes illuminance,
The optical system includes a plurality of lens members arranged linearly along the same optical axis between the lamp and the light irradiation window,
The lens barrel includes a plurality of lens barrel units, and each lens barrel unit holds the lamp and the plurality of lens members, respectively.
An inert gas supply port is provided above the position of the lamp in the lens barrel, and an inert gas discharge port is provided at the lower end surface of the lens barrel. The light irradiation apparatus characterized by being substituted by. The lens barrel unit includes a lamp lens barrel unit and a lens barrel unit, and the lens barrel unit is provided with a lens member holding portion,
The light irradiation device according to claim 1, wherein the lens member holding portion is formed with a vent hole for allowing an inert gas to flow from the upper surface side to the lower surface side of the lens member.   The light irradiation apparatus according to claim 2, wherein a wind direction plate that changes the outflow direction of the inert gas from the vent hole toward the lower surface of the lens member is provided below the vent hole. .   An exposure apparatus comprising: the light irradiation apparatus according to claim 1; a mask stage disposed below the light irradiation apparatus; and a work stage disposed below the mask stage. The exposure apparatus according to claim 4, wherein a coating member that covers an upper portion of the mask stage is provided below the light irradiation apparatus.

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