KR20090103847A - Exposure apparatus and device manufacturing method - Google Patents

Abstract

PURPOSE: An exposure apparatus is provided to maintain the transmittance ratio of the exposure light and prevent the contamination of the optical element. CONSTITUTION: The exposure apparatus(700) exposes the circuit pattern formed in the vacuum on the top of the substrate. The exposure apparatus includes the vacuum chamber(1~5), and wire electrode array(30). The vacuum chamber has a plurality of the regions. The wire electrode array has parallel wire electrodes. The wire electrode array has the first wire electrode group, and the second wire electrode group. The first wire electrode group is arranged to the opening(25~28) of the exposure light at a boundary between adjacent vacuum chambers. In the first wire electrode group, the AC voltage of the first phase is applied. In the second wire electrode group, the different from the first phase AC voltage of the second phases is applied.

Description

Exposure apparatus and device manufacturing method {EXPOSURE APPARATUS AND DEVICE MANUFACTURING METHOD}

The present invention relates to an exposure apparatus, and more particularly, to an exposure apparatus that effectively prevents contamination of an optical element in the apparatus.

In recent years, the exposure light used by the optical lithography technique for manufacturing a semiconductor is shortened and it progresses from i line | wire or g line | wire to KrF excimer laser light or ArF excimer laser light. By shortening the exposure light, a finer mask pattern can be transferred to the wafer.

However, in order to expose a pattern having a fine line width, the lithography technique in which ultraviolet light is used has a theoretical limit. Therefore, in recent years, EUV lithography technology using extreme ultraviolet light (EUV light, wavelength of 13-20 nm), which has a shorter wavelength than ultraviolet light, has attracted attention.

The typical wavelength used as EUV light is 13.5 nm. Thus, much higher resolution than conventional optical lithography techniques can be realized. At the same time, however, EUV light has a property of being easily absorbed by the material. Accordingly, as in the conventional lithography technique in which ultraviolet light is used as the light source, when the reduced exposure using the refractive optical system is performed, EUV light can be absorbed by the glass material, and the amount of light reaching the exposed object such as the wafer is extremely Less. Therefore, when exposure is performed using EUV light, a configuration of reduced exposure using a reflective optical system is required.

EUV light used for an EUV exposure apparatus is absorbed by the atmosphere in the apparatus. In particular, oxygen or moisture strongly absorbs EUV light. Accordingly, in order to maintain high transmittance of the EUV light, it is necessary to make the inside of the chamber into a vacuum state by using a vacuum pump or the like.

When exposing a circuit pattern in a semiconductor exposure apparatus, a photosensitive agent called a resist needs to be applied on the wafer surface. During the exposure, the exposure light and the resist applied to the wafer react to generate a release gas such as hydrocarbon. In the EUV exposure apparatus, since the energy of the EUV light is strong, a large amount of emission gas is generated.

The emission gas is scattered from the wafer into the projection optics space. When the emitted gas is irradiated from the surface of an optical element such as a multilayer mirror by exposure light, it is deposited as a contaminant on the surface of the optical element. If the emission gas is hydrocarbon, carbon is attached to the optical element surface. Contaminants adhering to the optical element absorb EUV light and reduce the reflectance of the optical element. If the reflectance of the optical element is reduced, it leads to a decrease in throughput.

Laser plasma, which is one type of EUV light source, generates EUV light from the target material by irradiating high intensity pulsed laser light to the target material. However, this also generates particles called debris. This debris are scattered into the light source space, contaminating or damaging the optical element and causing a decrease in reflectance. When the debris are scattered into the illumination optics space, the optical elements in the illumination optics are contaminated.

In EUV exposure apparatus, in order to maintain the light intensity of EUV light, a multilayer film mirror is provided in the light source space, the illumination optical system space, and the projection optical system space, and comprises a reflection optical system. It is known that secondary electrons are emitted when EUV light is irradiated to the multilayer film mirror. When these secondary electrons adhere to the optical element, the optical element is contaminated and the reflectance is reduced.

In the EUV exposure apparatus, there is a possibility that dust particles are scattered from the movable part of the stage in the apparatus chamber or the like. This particle also moves from the stage space into the projection optical system space and adheres to the optical element, thereby degrading the optical performance.

In addition, while the reticle or wafer is transported to the device chamber, particles are generated by slide or friction, such as the operation of the robot hand or the gate valve, and there is a possibility that they are attached to the reticle or wafer. Dust particles attached to the reticle or wafer may be scattered into the space in which the optical element is placed after the reticle or wafer is transported in the device chamber. As a result, dust particles generated outside the device chamber are transported in the device chamber and adhered to the surface of the optical element in the device chamber, thereby degrading the optical performance.

For example, Japanese Unexamined Patent Application Publication No. 2005-43895 discloses a method of providing a thin film at the boundary between a wafer stage space and a projection optical space so that the emission gas generated from the resist does not enter the projection optical space. have.

In the method of Japanese Patent Laid-Open No. 2005-43895, the movement of the emission gas or the dust particles can be physically blocked by the thin film. However, since the thickness of the thin film is 100 nm or less or very thin, the production of the thin film is very difficult. In addition, since the thin film has a thickness of 100 nm or less, a supporting mechanism such as a wire is required. Thereby, a thin film needs to be manufactured including the wire which is a support mechanism, and since there are many processes at the time of manufacture, it becomes expensive. Even when the thickness of the thin film is several hundred nm, the transmittance of EUV light at a wavelength of 13.5 nm is about 50%. As a result, the transmittance is not sufficiently maintained as compared with the case where there is no thin film.

The thin film is contaminated by adhesion of emission gas or particles to the thin film, and deterioration of the performance of the thin film is inevitable. Since the cleaning of the thin film itself can be difficult, it is necessary to replace the thin film and lead to a decrease in throughput.

As described above, in the prior art, particles such as emission gas, debris, secondary electrons, dust particles, and the like are prevented from entering and exiting each unit in an EUV exposure apparatus in which exposure light transmittance is maintained, thereby protecting the optical element from contamination. It was not possible to.

The present invention provides an exposure apparatus that effectively prevents contamination of an optical element in the apparatus while maintaining the transmittance of the exposure light. This invention also provides the high-precision device manufacturing method using this exposure apparatus.

An exposure apparatus as one aspect of the present invention is an exposure apparatus configured to expose a circuit pattern formed on a master plate on a substrate in a vacuum environment. The exposure apparatus includes a plurality of vacuum chambers that separate the interior of the exposure apparatus into a plurality of regions, and a wire electrode array having a plurality of parallel wire electrodes. The wire electrode array is disposed in the opening for passing exposure light at the boundary between adjacent vacuum chambers, and is provided with a first wire electrode group to which an AC voltage of a first phase is applied, and a second phase different from the first phase. Has a second wire electrode group to which an AC voltage of is applied.

A device manufacturing method as another aspect of the present invention includes exposing a substrate using an exposure apparatus, and developing the exposed substrate.

Other features and aspects of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.

The present invention provides an exposure apparatus that effectively prevents contamination of optical elements in the apparatus while maintaining the transmittance of the exposure light. This invention also provides the high-precision device manufacturing method using this exposure apparatus.

1 is a schematic configuration diagram of an exposure apparatus in this embodiment.

2 is a configuration diagram of a wafer stage space and a projection optical system space in the exposure apparatus of Example 1;

3 is a configuration diagram of a wire electrode string composed of two wire electrode groups provided in the exposure apparatus of Example 1. FIG.

4 is a configuration diagram of a wire electrode string composed of three wire electrode groups provided in the exposure apparatus of Example 1. FIG.

FIG. 5 is a waveform diagram of an AC voltage applied to a wire electrode string composed of two wire electrode groups shown in FIG. 3.

FIG. 6 is a waveform diagram of an AC voltage applied to a wire electrode string composed of three wire electrode groups shown in FIG. 4. FIG.

FIG. 7 is a view for explaining the effect of a wire electrode string composed of two wire electrode groups. FIG.

8 is a configuration diagram of an opening part for exposure light passage in the exposure apparatus of Example 1;

9 is a configuration diagram of a wafer stage space and a projection optical system space in the exposure apparatus of Example 2;

10 is a configuration diagram of a wafer stage space and a projection optical system space in the exposure apparatus of Example 3;

11 is a configuration diagram of a wafer stage space and a projection optical system space in the exposure apparatus of Example 4;

<Explanation of symbols for the main parts of the drawings>

1 ~ 5: vacuum chamber

6: reticle

7: reticle holding unit

8: reticle stage

9: wafer

10: wafer holding part

11: wafer stage

12: reticle alignment optical system

13: Wafer alignment optical system

14: focus position detection mechanism

100: light source

200: illumination optical system

400: projection optical system

700: EUV exposure device

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings. In each figure, the same elements are given the same reference numerals, and description thereof is omitted.

First, the exposure apparatus in this embodiment will be described schematically. 1 is a schematic configuration diagram of an exposure apparatus in this embodiment.

The EUV exposure apparatus 700 is an exposure apparatus that exposes a circuit pattern formed on a disc (reticle) on a substrate (wafer) in a vacuum environment. The EUV exposure apparatus 700 includes a plurality of vacuum chambers 1 to 5 that separate the interior of the exposure apparatus into a plurality of regions.

The vacuum chamber 1 constitutes a light source space, and a light source 100 is accommodated therein. The vacuum chamber 2 constitutes an illumination optical system space, and an illumination optical system 200 is accommodated therein. The vacuum chamber 3 constitutes a reticle stage space, in which a reticle stage 8 is accommodated. The vacuum chamber 4 constitutes a projection optical system space, and a projection optical system 400 is housed therein. The vacuum chamber 5 constitutes a wafer stage space, in which a wafer stage 11 is accommodated.

In the vacuum chamber 3 constituting the reticle stage space, a reticle holding unit 7 holding the reticle 6 and a reticle stage 8 for mounting the reticle holding unit 7 are provided. The vacuum chamber 3 is also provided with a reticle alignment optical system 12 which is used to align the reticle 6.

In the vacuum chamber 5 constituting the wafer stage space, a wafer holder 10 holding the wafer 9 and a wafer stage 11 on which the wafer holder 10 is mounted are provided. In addition, the vacuum chamber 5 is provided with a wafer alignment optical system 13 and a focus position detection mechanism 14 used to align the wafer 9.

The EUV light 15 emitted from the light source 100 is irradiated to the reticle 6 through the illumination optical system mirrors 16, 17 provided inside the vacuum chamber 2. The EUV light 15 reflected by the reticle 6 is irradiated onto the wafer 9 through the projection optical system mirrors 18 to 23 (multilayer film mirrors) provided inside the vacuum chamber 4.

There are several types of light sources 100. The laser generated plasma light source, which is one of the light sources, can emit light having only a substantially necessary wavelength band by selecting the target material 24. For example, Xe is ejected from a pulse nozzle as a target material, and when this is irradiated with a pulsed laser, plasma is generated, EUV light of wavelength 13-14 nm (for example, 13.5 nm) is radiated.

In the EUV exposure apparatus 700, in order to prevent the EUV light 15 from being absorbed by the material, the space to which the EUV light 15 is irradiated needs to be kept in a vacuum. Accordingly, the EUV exposure apparatus 700 is provided with a plurality of exhaust systems such as vacuum pumps. The pressure in the chamber through which the EUV light 15 passes is 10 ⁻³ Pa or less, and it is preferable that the partial pressures of oxygen and moisture are low indefinitely.

The illumination optical system 200 includes a plurality of illumination optical mirrors 16 and 17 (multilayer film mirrors), an optical integrator (not shown), and the like. The role of the illumination optical system 200 is to efficiently collect the light emitted from the light source 100, to make the illuminance of the exposure area uniform, and the like. In addition, the optical integrator has a role of uniformly illuminating the reticle 6 (mask) with a predetermined numerical aperture.

The projection optical system 400 includes projection optical system mirrors 18 to 23. Each of the projection optical system mirrors 18 to 23 is a multilayer film mirror coated with Mo and Si alternately. In this multilayer film, since the reflectance of EUV light directly incident is about 67%, most of the energy absorbed by the multilayer film mirror changes to heat. Accordingly, low thermal expansion glass or the like is used as the substrate material of the projection optical system mirrors 18 to 23.

The reticle stage 8 and the wafer stage 11 have a mechanism for driving in a vacuum environment, and perform synchronous scanning at a speed ratio proportional to the reduction magnification. The position and attitude of each of the reticle stage 8 and the wafer stage 11 are observed and controlled by a laser interferometer (not shown). Each of the reticle stage 8 and the wafer stage 11 includes a micromotion mechanism, and each of the reticle 6 and the wafer 9 can be positioned.

The alignment detection mechanism includes a reticle alignment optical system 12 and a wafer alignment optical system 13. The reticle alignment optical system 12 and the wafer alignment optical system 13 respectively measure the positional relationship between the optical axis of the reticle 6 and the projection optical system 400 and the positional relationship between the optical axis of the wafer 9 and the projection optical system 400. do. Based on the result, the position and angle of the reticle stage 8 and the wafer stage 11 are adjusted so that the projected image of the reticle 6 coincides with a predetermined position on the wafer 9.

The focus position detection mechanism 14 detects the focus position in the vertical direction on the wafer surface in order to maintain the imaging position of the projection optical system 400 on the wafer surface.

When one exposure is finished, the wafer stage 11 is moved step by step in the X direction and the Y direction and then moved to the next scanning exposure start position to perform the exposure again. At this time, particles such as emission gas, debris, secondary electrons, or dust particles are generated inside the EUV exposure apparatus 700. When these particles adhere to the optical element, the surface of the optical element is contaminated.

In the present embodiment, the openings 25 through through the exposure light, which are provided at the boundaries (walls 45, 46, 47, and 48) of adjacent vacuum chambers to prevent particles from freely entering and exiting each unit. A wire electrode string 30 is disposed at 28.

As shown in FIG. 1, the wire electrode string 30 includes an opening 25 at the boundary between the light source space (vacuum chamber 1) and the illumination optical system space (vacuum chamber 2), and the illumination optical system space ( It is arranged in the opening 26 at the boundary between the vacuum chamber 2 and the reticle stage space (vacuum chamber 3). The wire electrode rows 30 are projected with the opening 27 at the boundary between the reticle stage space (vacuum chamber 3) and the projection optical system space (vacuum chamber 4), and the wafer stage space (vacuum chamber 5). It is arrange | positioned at the opening part 28 of the boundary between optical system space (vacuum chamber 4).

In this way, the wire electrode string 30 provided in the opening of the boundary between adjacent vacuum chambers can prevent particles from freely entering and exiting each vacuum chamber (each unit).

Hereinafter, specific examples of the wire electrode string 30 will be described.

<Example 1>

First, Embodiment 1 of the present invention will be described. FIG. 2 shows the wafer stage space (vacuum chamber 5) and the projection optical system space (vacuum chamber 4) in the exposure apparatus of Example 1. FIG. In this embodiment, the wire electrode string 30 is disposed in the opening 28 for exposure light passage at the boundary between the wafer stage space (vacuum chamber 5) and the projection optical system space (vacuum chamber 4). .

The wire electrode string 30 is composed of a plurality of parallel wire electrodes. Two or more wire electrodes are arranged in a mesh shape horizontally arranged at equal intervals. The wire electrode string 30 includes a first wire electrode group to which an AC voltage having a first phase is applied, and a second wire electrode group to which an AC voltage having a second phase different from the first phase is applied.

The wire electrode string 30 prevents the charged particles 29 from invading adjacent spaces because alternating voltages having different phases are applied to each electrode group. Accordingly, the wire electrode string 30 acts to bounc the charged particles 29 or act as a non-contact electric field curtain carrying the charged particles 29. .

As a result, the particles 29 generated in the wafer stage space (vacuum chamber 5) do not enter the projection optical system space (vacuum chamber 4) through the opening 28. Similarly, the particles 29 generated in the projection optical system space (vacuum chamber 4) do not enter the wafer stage space (vacuum chamber 5) through the opening 28.

Next, the structure of the wire electrode string and its effect are demonstrated. FIG. 3 shows a wire electrode string composed of two wire electrode groups of the first wire electrode group Wa and the second wire electrode group Wb in this embodiment.

The first wire electrode group Wa is composed of a plurality of first wire electrodes Wa1 to Wa5. Similarly, the second wire electrode group Wb is composed of a plurality of second wire electrodes Wb1 to Wb5. The first wire electrodes Wa1 to Wa5 constituting the first wire electrode group Wa and the second wire electrodes Wb1 to Wb5 constituting the second wire electrode group Wb are alternately arranged.

In FIG. 3, the first wire electrode group Wa is composed of five first wire electrodes Wa1 to Wa5, and the second wire electrode group Wb is composed of five second wire electrodes Wb1 to Wb5. However, the number of the first wire electrodes included in the first wire electrode group Wa and the second wire electrodes included in the second wire electrode group Wb are not limited thereto. The first wire electrode group Wa may include at least one first wire electrode, and the second wire electrode group Wb may include at least one second wire electrode. However, it is preferable that the first wire electrode group Wa and the second wire electrode group Wb are each composed of a plurality of first wire electrodes and a plurality of second wire electrodes. The wire electrode string is composed of, for example, about 100 wire electrodes.

The first wire electrodes Wa1 to Wa5 and the second wire electrodes Wb1 to Wb5 are horizontally arranged at equal intervals and arranged in a mesh shape. The first wire electrodes Wa1 to Wa5 constituting the first wire electrode group Wa are connected to an AC power supply for applying an AC voltage Va having a first phase. The second wire electrodes Wb1 to Wb5 constituting the second wire electrode group Wb are connected to an AC power supply for applying an AC voltage Vb having a second phase.

As a material of the first wire electrodes Wa1 to Wa5 and the second wire electrodes Wb1 to Wb5, for example, stainless steel (SUS) is used. However, this embodiment is not limited to this. Other materials that can be durable and thin can also be used. For example, gold (Au), platinum (Pt), chromium (Cr), nickel (Ni) and the like may also be used.

It is preferable that the wire diameter D and the wire spacing P of the wire electrodes used in the exposure apparatus of the present embodiment satisfy D <100 µm and P> 100 µm, respectively. For example, the wire electrode string is composed of wire electrodes having a wire diameter D of 10 mu m and a wire spacing P of 250 mu m. The shorter the wavelength, the easier the exposure light is to be attenuated. Accordingly, when exposure light having a shorter wavelength is used, it is preferable that the wire diameter D is made smaller and the wire spacing P is made larger.

4 shows a wire electrode string composed of three wire electrode groups of the first wire electrode group Wa, the second wire electrode group Wb, and the third wire electrode group Wc.

In addition to the first wire electrode group Wa and the second wire electrode group Wb, the wire electrode string shown in FIG. 4 is a third wire electrode group Wc to which an AC voltage Vc having a third phase different from the first and second phases is applied. It includes.

The first wire electrodes Wa1 to Wa3, the second wire electrodes Wb1 to Wb3, and the third wire electrodes Wc1 to Wc3 are sequentially arranged. In other words, the wire electrodes constituting the respective wire electrode groups are sequentially and sequentially arranged one by one.

As shown in FIG. 4, the first wire electrode group Wa and the second wire electrode group Wb are each composed of three wire electrodes Wa1 to Wa3 and three wire electrodes Wb1 to Wb3, respectively. Similarly, the third wire electrode group Wc is composed of three wire electrodes Wc1 to Wc3. However, the number of wire electrodes included in each wire electrode group is not limited thereto. Each of the first wire electrode group, the second wire electrode group, and the third wire electrode group may include at least one wire electrode.

The first wire electrodes Wa1 to Wa3, the second wire electrodes Wb1 to Wb3, and the third wire electrodes Wc1 to Wc3 are horizontally arranged at equal intervals and arranged in a mesh shape. The first wire electrodes Wa1 to Wa3 constituting the first wire electrode group Wa are connected to an AC power supply for applying an AC voltage Va of the first phase. The second wire electrodes Wb1 to Wb3 constituting the second wire electrode group Wb are connected to an AC power source that applies an AC voltage Vb of the second phase. The third wire electrodes Wc1 to Wc3 constituting the third wire electrode group Wc are connected to an AC power supply for applying an AC voltage Vc of the third phase. The first phase of the AC voltage Va, the second phase of the AC voltage Vb, and the third phase of the AC voltage Vc applied by each AC power source are different from each other.

In the case where the wire electrode string is composed of three wire electrode groups, the wire electrode string acts to send an approaching particle in one direction. Accordingly, when the control is performed to guide the particles in a specific direction, it is preferable that the wire electrode string is composed of three or more wire electrode groups.

FIG. 5 is a waveform diagram of an alternating voltage applied to a wire electrode string composed of two wire electrode groups shown in FIG. 3.

As shown in FIG. 3, the wire electrode string is composed of two electrode groups of the first wire electrode group Wa and the second wire electrode group Wb. To each of the first wire electrode group Wa and the second wire electrode group Wb, AC voltages Va and Vb different in phase from each other by 180 ° are applied.

5 shows waveform diagrams of the AC voltages Va and Vb applied to the first wire electrode group Wa and the second wire electrode group Wb, respectively. The alternating voltages Va and Vb have phases 180 degrees different from each other under the conditions of voltage Vpp = 2 kV and frequency f = 10 kHz. Accordingly, the phase difference between the first phase applied to the first wire electrode group Wa and the second phase applied to the second wire electrode group Wb is preferably 180 °. However, the present embodiment is not limited to this, and if the first phase and the second phase are controlled to be different from each other, a phase difference other than 180 ° may be set.

FIG. 6 is a waveform diagram of an AC voltage applied to a wire electrode string including three wire electrode groups shown in FIG. 4.

As shown in FIG. 4, the wire electrode string is composed of three electrode groups of the first wire electrode group Wa, the second wire electrode group Wb, and the third wire electrode group Wc. AC voltages different in phase from each other by 120 ° are applied to each of the first wire electrode group Wa, the second wire electrode group Wb, and the third wire electrode group Wc.

6 shows waveforms of alternating voltages Va, Vb, and Vc applied to the first wire electrode group Wa, the second wire electrode group Wb, and the third wire electrode group Wc. The alternating voltages Va, Vb, and Vc have phases 120 ° different from each other under the conditions of voltage Vpp = 2 kV and frequency f = 10 kHz. Accordingly, the phase difference between the first phase applied to the first wire electrode group Wa, the second phase applied to the second wire electrode group Wb, and the third phase applied to the third wire electrode group Wc is set to 120 °. It is preferable. However, the present embodiment is not limited to this, and if the three phases are controlled to be different from each other, a phase difference other than 120 ° may be set.

The number of wire electrode groups is not limited to two or three, but four or more wire electrode groups may also be used. When generalizing the number of wire electrode groups to N, it is preferable that alternating voltages different in phase by 360 / N ° are applied to each of the wire electrode groups. However, the present embodiment is not limited to this, and if the phases of the AC voltages applied to each of the N wire electrode groups are controlled to be different from each other, a phase difference other than 360 / N ° may be set.

Next, with reference to FIG. 7, the effect obtained when a wire electrode string consists of two wire electrode groups is demonstrated.

The phases of the two wire electrode groups (the first wire electrode group Wa and the second wire electrode group Wb) are different from each other by 180 °. Accordingly, reverse voltages are applied to two adjacent wire electrodes, and an electric potential gradient is generated between the wire electrodes. When the charged particle 29 is close to the wire electrode string, the particle 29 is subjected to an electrostatic force by the potential gradient generated by two adjacent wire electrodes. The direction in which the electrostatic force acts is the tangential direction of the electric line of force formed between two wire electrodes adjacent to the particle 29.

An alternating voltage is applied to both wire electrode groups. Thus, as time passes, the plus and minus of the voltage applied to the wire electrode is switched. That is, as time passes, the direction of the electrostatic force acting on the particle 29 is reversed, and the particle 29 vibrates under the electrostatic force at a predetermined position. The electric line of force between the two wire electrodes is curved outwardly convex at positions other than the plane of the wire electrode string. As a result, centrifugal force is generated in the vibrating particle 29 and bounced from the wire electrode string. Therefore, the charged particles 29 that are close to the wire electrode string cannot enter the space arranged on the side opposite to the wire electrode surface.

When the phase difference between the two wire electrode groups is set to 180 degrees, the voltages applied to both wire electrode groups become zero at a predetermined point in time. Accordingly, it is preferable that the frequency of the alternating voltages applied to the two wire electrode groups is set higher. By increasing the frequency of the AC voltage, the period during which the voltage is not applied to the two wire electrode groups can be shortened.

The effect obtained when a wire electrode string consists of three or more wire electrode groups is as follows.

When AC voltages having different phases from each other are applied to three or more wire electrode groups, a traveling wave type non-uniform electric field is obtained on the surface constituting the wire electrode of the wire electrode string. When the charged particles 29 come close to the wire electrode array, the particles are held at a position away from the wire electrode surface by a traveling wave type non-uniform electric field and carried in a direction parallel to the wire electrode surface. As a result, the charged particles 29 approaching the wire electrode string cannot enter the space on the side opposite to the wire electrode surface.

As described above, when exposure light is incident on the wafer 9 to which the resist is applied, the emission gas is generated. The emitted gas is scattered from the wafer stage space (vacuum chamber 5) to the projection optical system space (vacuum chamber 4), adheres to the optical element, and degrades optical performance. Part of the emission gas is charged by the action on the exposure light.

As shown in FIG. 2, the wire electrode string 30 passes through the exposure light at the boundary between the wafer stage space (vacuum chamber 5) and the projection optical system space (vacuum chamber 4) (wall 48). It is arrange | positioned at the opening part 28 of a dragon. The wire electrode string 30 can prevent the charged emission gas from entering the projection optical system space (vacuum chamber 4) from the wafer stage space (vacuum chamber 5) through the opening 28.

FIG. 8: is a block diagram of the opening part 28 for exposure light passage in the boundary of a wafer stage space (vacuum chamber 5) and projection optical system space (vacuum chamber 4).

The side wall 31 of the opening 28 is covered with metal and grounded to the ground potential GND. As a result, since the metal grounded at the ground potential surrounds the wire electrode string 30 in the horizontal direction of the wire electrode surface, the electric field formed by the wire electrode string 30 generates electrical noise and causes the wire electrode string. Influence on the area | region away from 30 is suppressed.

The wire electrode is insulated from the metal portion of the side wall 31 of the opening 28. When the member of the side wall 48 which forms the boundary of the wafer stage space (vacuum chamber 5) and the projection optical system space (vacuum chamber 4) is made of metal, the wall 48 itself is grounded to the ground potential. . On the other hand, when the wall 48 is integrated with the exposure apparatus, the exposure apparatus is grounded to the ground potential.

The dust particles generated from the stage movable portion or the like present in the wafer stage space (vacuum chamber 5), or the dust particles attached to the wafer during the transport process and scattered back into the wafer stage space (vacuum chamber 5), It can be charged during its development. As a result, the wire electrode string 30 can prevent the charged dust particles from entering the projection optical system space (vacuum chamber 4) from the wafer stage space (vacuum chamber 5).

As described above, according to the configuration of the present embodiment, contamination of the optical element in the projection optical system space through the opening 28 by the charged emission gas or dust particles can be effectively prevented. In particular, according to the configuration of this embodiment, contamination by both plus and minus discharge gas and dust particles can be prevented.

The projection optical system mirrors 18 to 23 arranged in the projection optical system space (vacuum chamber 4) emit secondary electrons by the incidence of exposure light. If secondary electrons adhere to the optical element, optical performance is degraded. In the wire electrode string 30 disposed at the boundary between the wafer stage space (vacuum chamber 5) and the projection optical system space (vacuum chamber 4), secondary electrons are transferred from the projection optical system space (vacuum chamber 4). Intrusion into the stage space (vacuum chamber 5) can be prevented.

It is also prevented that positive or negatively charged dust particles generated in the projection optical system space (vacuum chamber 4) enter the wafer stage space (vacuum chamber 5) from the projection optical system space (vacuum chamber 4). Can be. Accordingly, according to the present embodiment, it is possible to effectively prevent the wafer from being contaminated through the openings 28 by secondary electrons or charged dust particles. According to this embodiment, the intrusion of the particle 29 in the bidirectional through the opening 28 can be prevented.

Next, the influence which the wire electrode string 30 has on the transmittance | permeability of exposure light is demonstrated.

In the exposure apparatus of this embodiment, when the wire diameter D and the wire spacing P of each of the wire electrodes satisfy D <100 μm and P> 100 μm, the illuminance of the exposure light is sufficiently small. That is, even when the wire electrode string 30 is disposed at the boundary between the wafer stage space (vacuum chamber 5) and the projection optical system space (vacuum chamber 4), the particles 29 are in a state where the transmittance of the exposure light is maintained. ) Can be prevented.

The wire electrode string 30 acts on the particles 29 as a non-contact electric field curtain. As a result, the wire electrode string 30 itself hardly deteriorates, and the shielding action of the particles is continuously maintained. In other words, the wire electrode string 30 functions as a particle shielding device that does not require periodic replacement, and the throughput of the exposure apparatus is not reduced.

In the present embodiment, the wire electrode string 30 is disposed in the opening 28 for exposure light passing through the boundary between the wafer stage space (vacuum chamber 5) and the projection optical system space (vacuum chamber 4). The arrangement position is not limited to this. As described above, if the particle 29 is disposed at the boundary between the vacuum chamber (unit) in the exposure apparatus in which it is generated and another vacuum chamber (unit) adjacent to each other, the wire electrode string may be disposed anywhere.

Generally, at this boundary, the minimum openings necessary for passing the exposure light are provided. Debris, secondary electrons, and dust particles include a light source space (vacuum chamber 1), an illumination optics space (vacuum chamber 2) and a projection optics space (vacuum chamber 4), and a reticle stage space (vacuum). In each of the chambers 3).

Accordingly, as another position where the wire electrode string 30 is preferably arranged, the opening 25 at the boundary between the light source space (vacuum chamber 1) and the illumination optical system space (vacuum chamber 2) can be considered. have. In addition, the wire electrode string 30 further includes an opening 26 at the boundary between the illumination optical system space (vacuum chamber 2) and the reticle stage space (vacuum chamber 3), and the reticle stage space (vacuum chamber 3). ) And the projection optical system space (vacuum chamber 4).

As described above, according to the configuration of the present embodiment, free movement of particles through the boundary between adjacent vacuum chambers (units) can be effectively prevented. Even when the wire electrode rows are arranged at these boundaries, the transmittance of the exposure light is maintained, and the transmittance is not substantially reduced.

<Example 2>

Next, Example 2 of the present invention will be described. 9 is a configuration diagram of a wafer stage space (vacuum chamber 5) and a projection optical system space (vacuum chamber 4) in the exposure apparatus of Example 2. FIG.

The exposure apparatus of the present embodiment is implemented in that the ionizer 32 for ionizing particles 29 generated inside the vacuum chambers 4 and 5 is disposed inside the vacuum chambers 4 and 5. It is different from the exposure apparatus of Example 1.

As the ionizer 32 of this embodiment, for example, a laser light source, a UV lamp, an electron beam source, an ion beam source, and the like are used. The ionizer 32 actively ionizes or charges the particles 29 while the particles 29 such as the emission gas are directed to the wire electrode string 30. As the charge amount of the particle 29 increases, the electrostatic force acting on the particle 29 increases, and the particle shielding effect of the wire electrode string 30 increases.

It is preferable that the ionizer 32 is arrange | positioned in the position which can irradiate the ionization beam to the particle 29 scattered toward the wire electrode string 30. In the case of a wafer stage space (vacuum chamber 5), it is preferable that an ionizing beam is irradiated between the vicinity of the wafer 9 and the wire electrode string 30. In the projection optical system space (vacuum chamber 4), it is preferable that the ionizing beam is irradiated in the vicinity of the projection optical system mirrors 18 to 23 or in the vicinity of the wire electrode string 30.

In the present embodiment, the ionizer 32 in the case where the wire electrode string 30 is disposed at the boundary between the wafer stage space (vacuum chamber 5) and the projection optical system space (vacuum chamber 4) has been described. . However, the installation place of the ionizer 32 of this embodiment is not limited to this. The wire electrode string 30 may be provided at a position other than a boundary between the wafer stage space (vacuum chamber 5) and the projection optical system space (vacuum chamber 4).

In this configuration, for example, near each of the wire electrode rows, near the target material 24 in the light source space (vacuum chamber 1), and illumination optical system mirrors in the illumination optical system space (vacuum chamber 2) The ionizer 32 may be disposed in the vicinity of 16 and 17 and in the vicinity of the reticle stage 8 in the reticle stage space (vacuum chamber 3). Accordingly, it is preferable that the ionizer 32 is disposed at a position where the ionization beam can be irradiated to the particles 29 scattered toward the wire electrode string 30.

According to the configuration of the present embodiment, the particle shielding effect of the wire electrode string 30 can be enhanced by irradiating an ionizing beam to the particles 29 moving toward the wire electrode string 30.

<Example 3>

Next, Example 3 of the present invention will be described. FIG. 10: is a block diagram of the wafer stage space (vacuum chamber 5) and projection optical system space (vacuum chamber 4) in the exposure apparatus of Example 3. As shown in FIG.

In the exposure apparatus of this embodiment, the auxiliary electrode 33 for trapping the charged particles 29 present in the vacuum chambers 4, 5 is provided in the vacuum chambers 4, 5, Embodiment 1 Is different.

The auxiliary electrode 33 immediately traps the particles 29 such as ionization emission gas bound by the wire electrode string 30, thereby preventing the particles 29 from reattaching to the optical element. As shown in Fig. 10, in each of the wafer stage space (vacuum chamber 5) and the projection optical system space (vacuum chamber 4), a pair of auxiliary electrodes 33 positively or negatively charged are provided. It is. That is, the positively charged auxiliary electrode 33 is disposed on the right side of FIG. 10, and the negatively charged auxiliary electrode 33 is disposed on the left side of the battery.

In the present embodiment, since the pair of auxiliary electrodes 33 positively or negatively charged are disposed in the vicinity of the wire electrode string 30, the charged particles 29 bound by the wire electrode string 30 are provided. Silver is captured by the auxiliary electrode 33 regardless of whether it is a plus particle or a minus particle. That is, the positively charged particle 29 is captured by the negatively charged auxiliary electrode 33, and the negatively charged particle 29 is captured by the positively charged auxiliary electrode 33.

In the exposure apparatus of this embodiment, the auxiliary electrode 33 in the case where the wire electrode string 30 is disposed at the boundary between the wafer stage space (vacuum chamber 5) and the projection optical system (vacuum chamber 4) will be described. It was. However, the present embodiment is not limited to this, and the wire electrode string 30 may also be disposed at another unit boundary (the boundary of the adjacent vacuum chambers).

Also in this configuration, since the pair of auxiliary electrodes 33 positively or negatively charged are disposed in the vicinity of the wire electrode string 30, the particles 29 bounced and charged by the wire electrode string 30 are charged. The reattachment to the optical element can be prevented.

<Example 4>

Next, Example 4 of the present invention will be described. 11 is a configuration diagram of a wafer stage space (vacuum chamber 5) and a projection optical system space (vacuum chamber 4) in the exposure apparatus of Example 4. FIG.

In the exposure apparatus of the present embodiment, the ionizer 32 similar to the second embodiment and the auxiliary electrode 33 similar to the third embodiment are disposed inside the vacuum chambers 4 and 5, and the first embodiment and the second embodiment. Is different.

In this embodiment, the ionizer 32 and the auxiliary electrode 33 are provided in the vicinity of the wire electrode string 30. The ionizer 32 can enhance both the particle shielding effect of the wire electrode string 30 and the particle trapping effect of the auxiliary electrode 33 by actively charging the particles 29.

In the present embodiment, the ionizer 32 and the auxiliary electrode (when the wire electrode string 30 is disposed at the boundary between the wafer stage space (vacuum chamber 5) and the projection optical system space (vacuum chamber 4)). 33) has been described. However, the present embodiment is not limited thereto, and as described in Embodiments 3 and 4, the ionizer 32 and the auxiliary electrode 33 are provided at the boundary of other units (the boundary between adjacent vacuum chambers). It may also be arranged in the vicinity of the wire electrode string 30. The ionizer 32 may also be placed at a location where the scattered particles 29 can be irradiated. Since the ionizer 32 and the auxiliary electrode 33 are disposed in the vicinity of the wire electrode string 30 provided at the other unit boundary, the particle shielding effect of the wire electrode string 30 and the particle trapping effect of the auxiliary electrode are also Can also be raised at other unit boundaries.

The exposure apparatus of each of the above embodiments is suitably used for manufacturing a device having a fine pattern, such as a semiconductor device. In particular, each of the above embodiments is an exposure apparatus that performs exposure using light having a short wavelength (0.5 to 50 nm), such as EUV light, or an exposure apparatus that performs exposure using an optical element such as a mirror or a lens in a high vacuum environment. It is suitably used for.

A device (semiconductor integrated circuit device, liquid crystal display device, etc.) is a process of exposing the substrate (wafer, glass plate, etc.) to which the photosensitive agent was applied using the exposure apparatus of one of the above-described embodiments, and developing the substrate. And other known processes.

According to each of the above embodiments, the optical element is contaminated by particles freely entering and exiting each unit, such as emission gas, debris, secondary electrons, or dust particles, in the EUV exposure apparatus while the transmittance of the exposure light is maintained. An exposure apparatus that can be prevented from being provided can be provided. According to each of the above embodiments, a high precision device manufacturing method using this exposure apparatus can also be provided.

Although the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims (10)

An exposure apparatus configured to expose a circuit pattern formed on a disc in a vacuum environment on a substrate, A plurality of vacuum chambers separating the interior of the exposure apparatus into a plurality of regions; And Wire electrode array having a plurality of parallel wire electrodes Including; The wire electrode string is disposed in an opening for passing exposure light at a boundary between adjacent vacuum chambers, and is provided with a first wire electrode group to which an AC voltage of a first phase is applied, and a second different from the first phase. An exposure apparatus having a second wire electrode group to which an alternating voltage of a phase is applied. The method of claim 1, An exposure apparatus in which first wire electrodes constituting said first wire electrode group and second wire electrodes constituting said second wire electrode group are alternately arranged. The method of claim 1, The wire electrode array further includes a third wire electrode group to which an AC voltage having a third phase different from the first phase and the second phase is applied. The method of claim 3, An exposure apparatus in which the first wire electrode constituting the first wire electrode group, the second wire electrode constituting the second wire electrode group, and the third wire electrode constituting the third wire electrode group are sequentially arranged. . The method according to any one of claims 1 to 4, And the wire electrode array is disposed in an opening provided at a boundary between a vacuum chamber accommodating a wafer stage and a vacuum chamber accommodating a projection optical system among the plurality of vacuum chambers. The method according to any one of claims 1 to 4, And the wire electrode array is disposed in an opening provided at a boundary between the vacuum chamber accommodating the reticle stage and the vacuum chamber accommodating the illumination optical system among the plurality of vacuum chambers. The method according to any one of claims 1 to 4, And the wire electrode array is disposed in an opening provided at a boundary between the vacuum chamber accommodating the illumination optical system and the vacuum chamber accommodating the light source among the plurality of vacuum chambers. The method according to any one of claims 1 to 4, And an ionizer configured to ionize particles generated in the vacuum chamber in the vacuum chamber. The method according to any one of claims 1 to 4, And an auxiliary electrode configured to capture charged particles existing inside the vacuum chamber. As a device manufacturing method, Exposing the substrate using an exposure apparatus; And Developing the exposed substrate Including; The exposure apparatus is configured to expose a circuit pattern formed on the original plate in a vacuum environment on the substrate, wherein the exposure apparatus, A plurality of vacuum chambers separating the interior of the exposure apparatus into a plurality of regions; And A wire electrode string having a plurality of parallel wire electrodes, The wire electrode string is disposed in an opening for passing exposure light at a boundary between adjacent vacuum chambers, and is provided with a first wire electrode group to which an AC voltage of a first phase is applied, and a second different from the first phase. A device manufacturing method having a second wire electrode group to which an alternating voltage of a phase is applied.