JP2000294863A - Laser oscillating device and aligner and manufacture of device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain uniform laser emission for realizing electromagnetic wave radiation which is made uniform as a whole in the longitudinal direction of a laser tube, and for sharply reducing any energy loss even if adopting a slot array structure. SOLUTION: Each slot 10 is arrayed in a row so that the longitudinal direction can be matched with the longitudinal direction of a waveguide 1, and a metallic wall 12 is formed so that the periphery of those slots 10 can be surrounded. Then, a clearance is formed between the slot 10 and the window part of the laser tube as a passage 11 of microwaves by the metallic wall 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser oscillation device for generating a laser beam by introducing an electromagnetic wave from a waveguide through a plurality of minute gaps formed in the waveguide wall into the laser tube. In particular, the present invention is suitably applied to a laser oscillation device using a microwave as an electromagnetic wave for exciting a laser gas, an exposure apparatus including the same, and a method of manufacturing a device.

[0002]

2. Description of the Related Art In recent years, so-called excimer lasers have attracted attention as the only high-power laser that oscillates in the ultraviolet region. In the electronics, chemical, and energy industries, specifically, metals, resins, and glasses are used. It is expected to be applied to processing of ceramics, semiconductors, etc., chemical reactions, and the like.

The functional principle of an excimer laser oscillation device will be described. First, Ar, K filled in the manifold
A laser gas such as r, Ne, F ₂ or the like is brought into an excited state by electron beam irradiation, electric discharge or the like. At this time, the excited F atoms combine with the inactive Kr and Ar atoms in the ground state to generate KrF ^* and ArF ^* , which are molecules existing only in the excited state. This molecule is called excimer. Excimers are unstable and immediately emit ultraviolet light and fall to the ground state. This is called bond-free transition or spontaneous emission. An excimer laser oscillation device that uses this excited molecule to amplify as light with the same phase in an optical resonator composed of a pair of reflectors and extract it as laser light It is.

[0004]

At the time of excimer laser emission, a microwave is mainly used as an excitation source of a laser gas as described above. The microwave is an electromagnetic wave having an oscillation frequency of several hundred MHz to several tens GHz. In this case, a microwave is introduced into the laser tube from the waveguide through a gap (slot) formed in the waveguide wall, thereby exciting the laser gas in the laser tube to a plasma state.

Here, even if the intensity distribution of the microwave emitted from the slot is uniform, in order to supply the microwave to a space long enough to fill the resonator length of the laser beam, it is necessary to use a long axis of the resonator. It is necessary to form a slot array structure in which a plurality of slots are arranged along a direction. This structure is shown in FIG. In FIG. 17, a plurality of minute gaps (slots) 202 are formed at equal intervals in a waveguide wall 201, and the inside of the laser tube is abbreviated as an emission space for convenience.

When this slot array structure is adopted,
An area between adjacent slots 202 (indicated by an oblique hatched portion in FIG. 17) is necessarily a non-irradiation area of the microwave. Therefore, even when the laser gas existing in the emission space is excited by the microwave, the microwave intensity becomes uneven due to the existence of the non-irradiation area, and a plasma discharge having a non-uniform distribution as a whole is generated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and employs a slot array structure, but realizes uniform radiation of electromagnetic waves over the entire length of the laser tube and minimizes energy loss. It is an object of the present invention to provide a laser oscillation device capable of emitting uniform laser light, a high-performance exposure device equipped with the laser oscillation device, and a method of manufacturing a high-quality device using the exposure device.

[0008]

According to the laser oscillation device of the present invention, a laser gas in the laser tube is introduced by introducing an electromagnetic wave from the waveguide through a plurality of minute gaps formed in the waveguide wall. A laser oscillation device that excites the laser beam to generate laser light by resonating light emitted from the laser gas, wherein a distance from the minute gap to the laser tube wall is separated by a predetermined distance, and the path of the electromagnetic wave is formed. ing.

In one aspect of the laser oscillation device of the present invention, a distance from the minute gap to the wall of the laser tube is an integral multiple of a half wavelength of the electromagnetic wave introduced from the waveguide in the tube.

In one embodiment of the laser oscillation device of the present invention, the electromagnetic wave introduced from the waveguide is a microwave.

In one embodiment of the laser oscillation device of the present invention, a conductor is provided so as to surround the passage including the small gap, and the passage extends in a longitudinal direction of the laser tube at a contact portion with the laser tube. The gap has a predetermined width.

In one embodiment of the laser oscillation device of the present invention, the gap is filled with a dielectric.

In one aspect of the laser oscillation device of the present invention, the width of the gap is an integral multiple of a half wavelength of the electromagnetic wave introduced from the waveguide in the tube.

In one aspect of the laser oscillation apparatus of the present invention, the gap has a narrow shape only at a tip portion thereof, and has a slit shape extending in a longitudinal direction of the laser tube at a contact portion with the laser tube. I have.

In one aspect of the laser oscillation device of the present invention, the gap is widened only in the vicinity of a tip portion thereof, and the width is substantially equal to a wavelength or a half wavelength of an electromagnetic wave introduced from the waveguide. Value.

In one embodiment of the laser oscillation device according to the present invention, the gap has a width in the vicinity of a tip portion thereof different along the longitudinal direction of the gap reflecting the intensity distribution of electromagnetic waves emitted from the minute gap. Value.

In one embodiment of the laser oscillation device of the present invention, a dielectric lens having a symmetrical structure with respect to the minute gap is provided at least above the minute gap in the passage.

In one embodiment of the laser oscillation device of the present invention, the waveguide is filled with a dielectric lens.

In one embodiment of the laser oscillation device of the present invention, the laser gas is used as at least one inert gas selected from Kr, Ar and Ne, or a mixture of the at least one inert gas and F ₂ gas. This is an excimer laser oscillation device using gas.

The exposure apparatus according to the present invention is characterized in that the laser oscillation device is a light source that emits illumination light, a first optical system for irradiating the reticle on which a predetermined pattern is formed with illumination light from the laser oscillation device, and the reticle. And a second optical system that irradiates the illumination surface with illumination light through the reticle, and projects a predetermined pattern of the reticle onto the illumination surface to perform exposure.

According to the method for manufacturing a device of the present invention, a step of applying a photosensitive material to a surface to be illuminated,
The method includes a step of performing a predetermined pattern exposure on the irradiated surface to which the photosensitive material is applied, and a step of developing the photosensitive material that has been subjected to the predetermined pattern exposure.

In one aspect of the device manufacturing method of the present invention, the surface to be irradiated is a wafer surface, and a semiconductor element is formed on the wafer surface.

[0023]

In the laser oscillation device according to the present invention, a path from the plurality of minute gaps (slots) formed in the waveguide wall to the laser tube wall is separated by a predetermined distance, and the path of the electromagnetic wave is formed. . In this case, the electromagnetic wave emitted from each minute gap has a flattened wavefront near the wall of the laser tube, and propagates into the laser tube as a plane wave approximation as a whole. Therefore, the electromagnetic wave which is made into a substantially uniform plane wave reaches the laser gas in the laser tube, and a uniform plasma discharge is realized in the longitudinal direction of the laser tube, thereby contributing to uniform laser emission.

More specifically, by setting the distance from the minute gap to the laser tube wall to be an integral multiple of a half wavelength of the electromagnetic wave introduced from the waveguide in the tube, the electromagnetic waves emitted from each minute gap can be reduced. The laser beam does not interfere with the reflected wave and reaches the inside of the laser tube without weakening.

Further, by providing a conductor so as to surround the passage including the minute gap and making the passage a gap having a predetermined width, energy loss can be minimized. Alternatively, by setting the width of the electromagnetic wave to an integral multiple of a half wavelength in the tube, a resonance condition can be given in the vertical direction of the minute gap, and the electric field in the slit can be set high.

Further, by filling the gap with a dielectric, plasma generation in the passage can be suppressed, and plasma discharge can be reliably induced only in the laser tube.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings.

(First Embodiment) First, a first embodiment will be described. In the present embodiment, an excimer laser oscillation device that emits a so-called excimer laser light is exemplified.
FIG. 1 is a schematic diagram illustrating a main configuration of an excimer laser oscillation device according to the present embodiment.

As shown in FIG. 1, the excimer laser oscillation device emits laser light by resonating light emitted by excitation of the excimer laser gas, and excites the excimer laser gas in the laser tube 2 to form a plasma state. And a cooling vessel 7 having a cooling water inlet / outlet 9 for cooling the waveguide 1.

The excimer laser gas used as a raw material for generating the excimer laser light is one or more inert gases selected from Kr, Ar and Ne, or a mixture of the one or more inert gases and F ₂ gas. It is a mixed gas. Of these, gas types may be appropriately selected and combined depending on the wavelength to be used. For example, when it is desired to generate a laser beam having a wavelength of 248 nm, Kr / Ne / F ₂ is used. For a wavelength of 193 nm, Ar / Ne / F _{2 is used} . For a wavelength of 157 nm, Ne / F ₂ is used. do it.

The laser tube 2 is provided with a laser gas inlet / outlet 8 for introducing an excimer laser gas into the tube and reflecting structures 5 and 6 at each end. Laser light is generated with the light phases aligned.

The waveguide 1 is a means for supplying microwaves to the laser gas in the gas supply path structure 11 and is shown in FIG.
A plurality of elongated slots 10 are formed in the middle upper surface. When a microwave having a frequency of several hundred MHz to several tens GHz is introduced from the upper part of the waveguide 1, the microwave is emitted from the slot 10 to the outside of the waveguide 1 while propagating in the waveguide 1. Is done. The emitted microwave is applied to the laser tube 2
Is introduced into the laser tube 2 through a window 15 provided in the laser tube 2. Then, the excimer laser gas in the laser tube 2 is excited by the introduced microwave, and resonates to generate excimer laser light.

In the present embodiment, the waveguide 1 is provided with a conductor plate which separates the waveguide 1 and the laser tube wall apart from each other by a predetermined distance at a portion other than a region on the slot 10, in this case, the metal wall 1.
2 (see FIG. 2).

FIGS. 2 and 3 show a specific state of the waveguide 1. FIG. Here, FIG. 2A is a schematic perspective view of the waveguide 1, FIG. 2B is a plan view thereof, and FIG.
FIG. 3B is a sectional view taken along line II-II ′ in FIG.
FIG. 2B is a sectional view taken along line II ′ in FIG. 2B.

As shown in FIG. 2B, each slot 10
Are arranged in a line so that the longitudinal direction thereof coincides with the longitudinal direction of the waveguide 1, and a metal wall 12 is provided so as to surround the periphery of these slots 10. FIG. 3 (a),
As shown in (b), the metal wall 12 forms a gap over the entire region of the waveguide 1 in the longitudinal direction of the laser tube 2 between the slot 10 and the window 15 of the laser tube wall. It becomes a microwave passage 11.

In this embodiment, the case where the slot 10 is formed on the so-called E-plane of the waveguide 1 is exemplified. When the slot 10 is formed on the H-plane, a passage corresponding to a portion where the slot 10 is formed is provided. It is necessary to provide a metal wall so that is formed.

Here, the separation distance from the slot 10 to the window 15 of the wall of the laser tube is an integral multiple of a half wavelength of the microwave introduced from the waveguide 1 in the tube, that is, the wavelength of the microwave in the tube is λg, Let n be an integer, and let d = n × λg / 2 (1) be the distance d. Thus, the passage 11 functions as a resonator, and the microwave emitted from each slot 10 does not interfere with the reflected wave from the inside of the laser tube 2 to be weakened.

The value of the integer n is arbitrary, but if it is too large, the loss due to the absorption of the microwave by the metal wall 12 when the microwave propagates through the passage 11 as described later. It is not preferable because it becomes large. Therefore,
Most preferably, the integer n is set to about 3 as described later.

For the same reason, the width of the passage 11 is also an integral multiple of a half wavelength of the microwave introduced from the waveguide 1, that is, w = n × λg / 2 (2) And a width w represented by

Hereinafter, the function of the waveguide 1 having the passage 11 will be described. As the microwave propagates through the waveguide 1, a current flows through the waveguide wall. Microwave
It exists as a standing wave in the propagation space defined by the longitudinal distance of the waveguide 1, and due to this standing wave, the current on the waveguide wall also takes the form of a standing wave. However, the form of the standing wave of the microwave is three-dimensional and complicated, and it is convenient to consider the standing wave of the current of the general distributed constant line as an index.

FIG. 4 shows an example using the standing wave of the current as an index.
Shown in As described above, in the present embodiment, the slot 10 is arranged so that the formation site thereof corresponds to the antinode portion of the standing wave of the current (that is, the standing wave of the microwave).
Therefore, as shown in FIG. 5, immediately after being emitted from the slots 10, the wavefront of the microwave has a discontinuous curved surface shape corresponding to each slot 10 due to the array shape of each slot 10. Then, the microwaves gradually approach the plane wave by propagating from each slot 10 through the passage 11 regulated by the metal wall 12, pass through the passage 11, and pass through the outside (ie, outside).
When emitted into the laser tube 2), the wavefront has a generally planar shape over the entirety along each slot 10.

Accordingly, the microwave which has become a substantially uniform plane wave reaches the excimer laser gas in the laser tube 2, and a uniform plasma discharge is realized in the longitudinal direction of the laser tube 2, and the laser emission becomes uniform. To contribute.

Here, a modified example of this embodiment will be described. Note that the same reference numerals are given to components and the like corresponding to the embodiment, and description thereof is omitted.

(Modification 1) In this modification 1, FIG.
As shown in (a) and (b) (the cross-sectional views similar to FIG. 3 in each drawing), the metal wall 12 is formed so that only the distal end portion 13 of the passage 11 becomes narrow. In this case, the tip portion 13 of the passage 11 has a slit shape extending in the longitudinal direction of the laser tube 2 at a contact portion (that is, the window portion 15) with the laser tube 2.

By forming the passage 11 in such a shape, unintended dissipation of energy when microwaves are emitted into the laser tube 2 can be further suppressed.

(Modification 2) In this modification 2, FIG.
7 (a) and FIG. 6 (a), the dielectric 1 is filled so as to fill the inside of the passage 11 as shown in FIGS. 7 and 8, respectively.
4 is provided. As a material of the dielectric 14, quartz, calcium fluoride, aluminum nitride, alumina, zirconia, and the like are preferable.

By filling the passage 11 with the dielectric material 14, generation of plasma inside the passage 11 can be prevented. The dielectric 14 used at this time preferably has a high dielectric constant and a small dielectric loss in order to transmit microwaves more efficiently.

Here, in order to simultaneously release a large amount of heat generated by plasma to the outside at high speed, the dielectric 14 is required to have high thermal conductivity. Furthermore, considering exposure to an atmosphere containing highly reactive F ₂ or the like such as an excimer laser, it is also important to have sufficient resistance to such corrosive gases. If the emission end of the microwave, that is, the surface that is in contact with the plasma, is sputtered by ion irradiation of several to several hundreds eV (depending on plasma potential) from plasma in addition to high temperature of 100 to 1000 ° C. (depending on incident energy) Extremely harsh environment. Therefore, in some cases, AlN or alumina having high thermal conductivity and relatively high F ₂ resistance is used as the material of the dielectric 14, and its surface (interface with plasma) is made of CaF ₂ , LiF ₂ , MgF _{2 or} the like. By coating with a fluoride of several μm to several hundred μm, both the same title of heat conduction and resistance to corrosive gas and sputtering can be achieved.

The energy loss in the passage 11 is 2
Divided into two. That is, the dielectric loss in the filled dielectric and the loss in the drawing tube wall. The attenuation constant α due to dielectric loss is represented by α = ωμσ / 2β (3) (ω: angular frequency / μ: magnetic permeability / σ: electric conductivity / β: phase constant). Regarding the loss in the tube wall, focusing on the TE10 mode,

[0050]

(Equation 1)

Is given by (Ξ: radio wave impedance / δ: skin depth) It is only necessary that the more dominant loss of the two is smaller than the energy supplied to the plasma, for example. That is, when the microwave absorptivity of the plasma is r, r≪1 when the plasma is in a cutoff state.
In consideration of the reciprocation (multiple reflection) between the slot surface and the plasma interface, the uniformized line is obtained by using n satisfying exp (-2α · nλg / 2) <r (4) Can be defined.

However, in terms of microwave efficiency, it is important to set the loss to be lower than the absorptance r, and it is preferable to design such that the loss is reduced by about 1/10 to 1/100 of r. With such settings, a system with less loss can be designed.)

Here, a specific experimental example in which the dielectric material 14 is filled in the passage 11 will be described below. a = 42 mm,
b = 21 mm, using an E-plane emission antenna having a waveguide resonator length (longitudinal direction, ie, laser oscillation direction) of 220.8 mm,
A microwave irradiation antenna having a 2.45 GHz Al alloy housing having a metal wall 12 disposed in front of the slot was manufactured. The waveguide resonator, that is, the passage 11 is filled with alumina having a dielectric constant of 9.8. At this time, the guide wavelength in the waveguide resonator is 44.2 mm. Therefore, the slot pitch is also set to 44.2 mm.

The microwaves emitted from the slots are emitted into the passage 11. This passage 11 is approximately a parallel-plate waveguide, under which the wavelength is equal to the wavelength in free space (however, inside the dielectric) 39.1 mm.
It is. Actually, the length 23 of the passage 11 in the laser oscillation direction
Although a rectangular waveguide having 5.3 mm as a is used, the guide wavelength at this time is 39.2 mm, which is only about 3.5 × 10 ^-3 as compared with the wavelength in free space. It is also possible to use a wavelength approximation of the space length. The half wavelength at this time is 19.6 mm, and the distance from the slot 10 surface of the passage 11 to the emission surface is 19.6 mm, 39.2 mm, 58.8 mm. Given.

Here, the loss in the resonator is considered.
Α due to dielectric loss is 10 ¹¹ Ωcm
In this case, it is 5.22 × 10 ⁻⁷ dB / m, and the loss due to the tube wall absorption is caused by the resistivity of alumina being 2.65 × 10 ⁻⁶ Ω ·
In cm, it is 0.234 dB / m. In this case, the dominant loss is the absorption of the tube wall, so attention is paid to this.
Every time the rod travels 19.6 mm, a loss of 0.0053% occurs with respect to the energy propagating through the waveguide. Therefore, for example, in order to suppress the loss during one round trip of the passage 11 to about 0.02% of the input energy, n is set to 4 (loss: 0.
21%) is set to 3 which is smaller than 21% and can obtain the most uniform effect. In practice, since multiple reflections occur, it is necessary to keep such a low loss level.

(Third Modification) In the third modification, FIG.
As shown in FIGS. 9A and 9B (cross-sectional views similar to FIGS. 3A and 3B), only the vicinity of the distal end portion 13 of the passage 11 is wide, specifically, The metal wall 12 is formed so that the passage 11 has a wide portion 16 having a half width α of α = λg / 4 or α = λg / 2.
To form

In this case, the wide portion 16 is formed so as to follow the passage 11 and extends over the entire area of the waveguide 1 in the longitudinal direction of the laser tube 2, and the wide portion 16 is formed to have the width as described above. Therefore, it is possible to efficiently concentrate the energy of microwave resonance in the wide portion 16.

A waveguide having this structure added to the waveguide having the structure described in the second modification was manufactured. At this time, α
Are 19.6 mm and 39 mm for λg / 4 and λg / 2, respectively, and the height of 16 is designed as 5 mm. The thickness of the passage 11 is 4 mm. At this time, the energy existing in 16 is 31.3% / 47.7% of the energy existing in passages 11 and 16, respectively.
From this, a portion close to the window portion 15 (that is, 16)
It can be seen that energy is concentrated in the area. In this comparison, it seems that the energy is more concentrated when α is λg / 2, but from the center of 16 λg / 4
Focusing on the energy of the microwave existing within the distance of (i.e., in the vicinity of the slot 10), when the energy existing in the passages 11 and 16 is 31.3% / 23.8%, and α is λg / 4 Can be said to be more effective in concentrating energy near the slot 10.

FIG. 10 shows another embodiment of the third modification. In this case, the width of the wide portion 16 has a different value along the longitudinal direction of the laser tube 2 reflecting the intensity distribution of the microwave emitted from the slot 10. That is, here, in addition to providing the metal wall 12 and forming the passage 11,
In order to further uniform the wavefront of the microwave, the passage 11
The width (or half width α) of the wide portion 16 is changed in accordance with the non-uniformity at the emission site so as to further correct the uniformity at the microwave emission site.

As a result, the microwave, which has been made into a more uniform plane wave, reaches the excimer laser gas in the laser tube 2, and a uniform plasma discharge is realized in the longitudinal direction of the laser tube 2, thereby further increasing the laser emission. It contributes to uniformity.

This effect is due to the inherent property of microwaves that the characteristics of the propagation path can be changed by changing the shape of the spatial gap. The impedance Z of the terminal short-circuited waveguide having a length L characteristic impedance Z ₀
Is as follows: Z = jZ ₀ tan ((2π / λg) L) This means that any value of inductive element (inductance and coil in discrete element) and capacitive element (capacitance and capacitor in discrete element) having any value can be formed only by changing L. . Changing the half-value width α in the slot line direction means that the impedance of the slot for electromagnetic waves is also changed (in terms of an equivalent circuit, a coil having various values continuously with respect to the slot). And capacitors are connected in parallel), so that the distribution of electromagnetic waves emitted from the slots can be controlled.

(Modification 4) In Modification 4, as shown in FIG. 11, a dielectric lens 17 having a curved surface symmetrical to the slot 10 is provided above each slot 10 in the passage 11. Have been. As this curved surface shape,
Depending on the shape and size of the slot 10 and the microwave to be emitted, a combination of a spherical surface, an aspherical surface (elliptical shape, hyperbolic shape, etc.), and a rectangular shape may be used. The dielectric lens 17 is applicable to any structure having a lens effect against microwaves, including a zoning lens.

The dielectric lens 17 has a dielectric constant and the above-mentioned curved surface shape for eliminating a phase shift due to a difference in path of the microwave passing through the slot 10 when the microwave wavefront shape is made uniform. is there. Generally, when a microwave propagates through a dielectric, its speed becomes slower than that in a vacuum (or in air). Therefore, by designing the dielectric lens 17 as described above, it becomes proportional to the path difference. The wavefront can be adjusted to make the wavefront uniform.

In this case, it is preferable to optimize the dielectric constant and the curved surface shape in consideration of the reflection in the generated plasma and in consideration of the multiple reflection. Alternatively, the thickness of the dielectric lens 17 is set to λg / 2 to minimize the reflection.
(When the dielectric constants before and after the lens are both high / low) or an odd multiple of λg / 4 (other times).

FIG. 12 (FIG. 1) shows another modification of the fourth modification.
1 is a plan view similar to FIG. This is the dielectric lens 18
This is an example in which are disposed not at a position immediately above each slot 10 but at a predetermined distance in the passage 11 and the curved surface shape is an aspherical surface.

In FIG. 11 and FIG.
1 is filled with a dielectric, the dielectric lens 1
It is needless to say that a similar effect can be obtained by forming a gap in the shape of the dielectric lenses 17 and 18 in the dielectric in the passage 11 instead of using the gaps 7 and 18.

(Modification 5) In this modification 5, FIG.
As shown in FIGS. 13A and 13B (similar to FIGS. 3A and 3B), the waveguide 1 is filled with a dielectric 19. Here, assuming that λc is a cutoff frequency, the relationship between the wavelength λ of the emitted microwave and the guide wavelength λg is

[0068]

(Equation 2)

Is represented by That is, in the E-plane radiation, since the interval between the slots 10 is λg or λg / 2, when the waveguide 1 is filled with a dielectric having a high dielectric constant, if the dielectric 19 is not a ferromagnetic, the dielectric constant can be reduced. Becomes smaller in inverse proportion to the square root of, the pitch of the guide wavelength λg becomes narrower, and more uniform microwave emission becomes possible.

Examples of usable dielectrics include those shown in Table 1 below. However, in general, as the dielectric constant increases, the dielectric loss increases.

[0071]

[Table 1]

By filling these dielectrics into the waveguide 1, the guide wavelength in the waveguide 1 becomes smaller at the wavelength ratio described in the ratio of Table 1, and the microwave wavefront is sufficiently uniform. Can be achieved.

(Modification 6) In Modification 6, when it is desired to double the pitch of the waveguide 1 at a higher frequency, for example, 2.45 GHz, a microwave having a frequency of about 4.9 GHz is used. Is adopted. As a result, the wavelength λ changes in inverse proportion to the frequency, and the pitch of the slots 10 can be reduced.

(Modification 7) In this modification 7, the waveguide 1
Is made as large as possible. As the cut-off frequency λc of the waveguide 1 is increased within a range where microwaves in the excitation frequency band are not cut off, the guide wavelength λg approaches the wavelength λ and becomes smaller. Therefore, for example, TE10
When only the mode is propagated, the pitch of the slots 10 can be reduced by increasing the H-plane width as much as possible. Conditions for propagating only the TE10 mode are as follows:
Assuming that the H-plane width is a, a <λ (<2a), so that the H-plane width a is given by (λ / 2 <) a <λ. Here, () is a condition for excluding a condition that does not pass through the TE10 mode, that is, a condition that microwaves of all modes cannot propagate. Therefore, by setting the H-plane width a to about the wavelength λ, the guide wavelength λg can be reduced to the minimum value 2/3 ^1/2 λ (≒ 1.15) without exciting the TE20 mode.
λ). If multimode excitation is allowed,
The guide wavelength λg asymptotically approaches the minimum value λ.
It is not realistic because it becomes ∞.

As described above, according to the excimer laser oscillating device of the present embodiment and its various modified examples, even though the slot array structure is adopted, the uniform emission of the electromagnetic waves over the entire length of the laser tube is realized. In addition, uniform laser emission with minimum energy loss can be achieved.

(Second Embodiment) Hereinafter, a second embodiment will be described. In the second embodiment, an exposure apparatus (stepper) having the excimer laser oscillation device described in the first embodiment as a laser light source is exemplified. FIG.
FIG. 2 is a schematic diagram showing a main configuration of the stepper.

The stepper includes an optical system 1 for irradiating a reticle 101 on which a desired pattern is drawn with illumination light.
11, a projection optical system 112 for projecting illumination light through the reticle 101 to reduce and project the pattern of the reticle 101 onto the surface of the wafer 102, a wafer chuck 113 on which the wafer 102 is mounted and fixed, and a wafer It has a wafer stage 114 to which the chuck 113 is fixed. As the reticle, not only a transmission reticle (reticle 101) as shown in the figure but also a reflection reticle can be applied.

The optical system 111 converts the illumination light from the light source 121 into a desired light beam shape, and the excimer laser oscillation device 121 according to the first embodiment, which is a light source that emits high-brightness excimer laser light as illumination light. The beam shape conversion unit 122, an optical integrator 123 in which a plurality of cylindrical lenses and minute lenses are arranged two-dimensionally, and a switch (not shown) can be switched to an arbitrary aperture, and are formed by the optical integrator 123. A diaphragm member 12 arranged near the position of the secondary light source
4, a condenser lens 125 for condensing the illumination light passing through the aperture member 124, and, for example, four variable blades, which are arranged on the conjugate plane of the reticle 101 to arbitrarily adjust the illumination range on the surface of the reticle 101. The blind 127 to be determined, the imaging lens 128 for projecting the illumination light determined in the predetermined shape by the blind 127 onto the surface of the reticle 101, and the bending for reflecting the illumination light from the imaging lens 128 toward the reticle 101. Mirror 129
And is configured.

The operation of reducing and projecting the pattern of the reticle 101 onto the surface of the wafer 102 using the stepper configured as described above will be described.

First, the illumination light emitted from the light source 121 is converted into a predetermined shape by the beam shape conversion means 122 and then directed to the optical integrator 123. At this time, a plurality of secondary light sources are formed near the exit surface. Illumination light from the secondary light source is condensed by the condenser lens 125 via the aperture member 124 and is
After being determined to have a predetermined shape, the light is reflected by the bending mirror 129 via the imaging lens 128 and enters the reticle 101. Subsequently, the light passes through the pattern of the reticle 101 and enters the projection optical system 122. Then, the projection optical system 122
, The pattern is reduced to a predetermined size, projected onto the surface of the wafer 102, and exposed.

According to the stepper of this embodiment, since the excimer laser oscillation device of the first embodiment is used as a laser light source, high-power and uniform excimer laser light can be emitted for a relatively long time. Can be quickly and accurately performed.

Next, an example of a method for manufacturing a semiconductor device (semiconductor device) using the projection exposure apparatus described with reference to FIG. 14 will be described.

FIG. 15 shows a semiconductor device (IC or LSI).
2 shows a flow of a manufacturing process of a semiconductor chip such as a liquid crystal panel or a CCD. First, in step 1 (circuit design), a circuit of a semiconductor device is designed. Step 2 is a process for making a mask on the basis of the circuit pattern design. On the other hand, in step 3 (wafer manufacturing), a wafer is manufactured using a material such as silicon. Step 4 (wafer process) is referred to as a pre-process, and actual circuits are formed on the wafer by photolithography using the mask and wafer prepared as described above. The next step 5 (assembly) is called a post-process, and step 4
This is a process of forming a semiconductor chip using the wafer produced by the above, and includes processes such as an assembly process (dicing and bonding) and a packaging process (chip encapsulation). In step 6 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device manufactured in step 5 are performed. Through these steps, a semiconductor device is completed and shipped (step 7).

FIG. 16 shows a detailed flow of the wafer process. Step 11 (oxidation) oxidizes the wafer's surface. In step 12 (CVD), a conductive film or an insulating film is formed on the wafer surface by using a gas phase reaction. Step 1
In 3 (PVD), a conductive film or an insulating film is formed on a wafer by sputtering or vapor deposition. Step 14 (ion implantation) implants ions into the wafer. Step 15
In (resist processing), a photosensitive agent is applied to the wafer. Step 16 (exposure) uses the projection exposure apparatus described above to expose the circuit pattern of the mask onto the wafer by printing. Step 17 (development) develops the exposed wafer. In step 18 (etching), portions other than the developed resist image are removed. In step 19 (resist stripping), the unnecessary resist after etching is removed.
By repeating these steps, multiple circuit patterns are formed on the wafer.

By using this manufacturing method, it is possible to easily and surely manufacture a highly integrated semiconductor device, which has been conventionally difficult to manufacture, with a high yield.

[0086]

According to the present invention, even though the slot array structure is employed, uniform emission of electromagnetic waves over the entire length of the laser tube is realized, and uniform laser emission with minimum energy loss can be achieved. Become.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a main configuration of an excimer laser oscillation device according to a first embodiment.

FIG. 2 is a schematic diagram showing a specific state of a waveguide.

FIG. 3 is a schematic sectional view showing a specific state of the waveguide.

FIG. 4 is a schematic diagram showing a relationship between a slot position of a waveguide and a current density generated by microwaves.

FIG. 5 is a schematic cross-sectional view showing a state where microwaves are emitted from a slot.

FIG. 6 is a schematic cross-sectional view showing a specific state of a waveguide according to a first modification.

FIG. 7 is a schematic cross-sectional view showing a specific state of a waveguide in Modification 2.

FIG. 8 is a schematic cross-sectional view showing a specific state of a waveguide in a second modification.

FIG. 9 is a schematic cross-sectional view showing a specific state of a waveguide according to a third modification.

FIG. 10 is a schematic plan view showing a specific example of another example of the waveguide in Modification 3.

FIG. 11 is a schematic cross-sectional view showing a specific state of a waveguide according to a fourth modification.

FIG. 12 is a schematic cross-sectional view showing a specific example of another example of the waveguide in Modification 3.

FIG. 13 is a schematic diagram showing a specific state of a waveguide in Modification Example 5.

FIG. 14 is a schematic view illustrating a stepper according to a second embodiment.

FIG. 15 is a flowchart of a semiconductor device manufacturing process using the stepper of the second embodiment.

FIG. 16 is a flowchart showing the wafer process in FIG. 15 in detail.

FIG. 17 is a schematic sectional view showing a specific state of a conventional waveguide.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Waveguide 2 Laser tube 5, 6 Reflection structure 7 Cooling container 8 Laser gas inlet / outlet 9 Cooling water inlet / outlet 10 Slot 11 Passage 12 Metal wall 13 Tip part 14 Dielectric 15 Window 16 Wide part 17, 18 Dielectric lens Reference Signs List 19 dielectric 101 reticle 102 wafer 111 optical system 112 projection optical system 113 wafer chuck 114 wafer stage 121 excimer laser oscillation device 122 beam shape conversion means 123 optical integrator 124 aperture member 125 condenser lens 127 blind 128 imaging lens 129 bending mirror

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Masaki Hirayama, No. 103, Pansion Aihara, 52, Funacho, Wakabayashi-ku, Sendai City, Miyagi Prefecture. 72) Inventor Nobuyoshi Tanaka 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Nobumasa Suzuki 3-30-2 Shimomaruko 3-chome, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Dai Osawa 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term (reference) in Canon Inc.

Claims (15)

[Claims] An electromagnetic wave is introduced into a laser tube from a waveguide through a plurality of minute gaps formed in the waveguide wall to excite a laser gas in the laser tube and resonate light emitted from the laser gas. A laser oscillation device for generating a laser beam, wherein a distance between the minute gap and the wall of the laser tube is separated by a predetermined distance, and a passage for the electromagnetic wave is formed. 2. The laser oscillation device according to claim 1, wherein a separation distance from the minute gap to the wall of the laser tube is an integral multiple of a half wavelength of an electromagnetic wave introduced from the waveguide. . 3. The laser oscillation device according to claim 1, wherein the electromagnetic wave introduced from the waveguide is a microwave. 4. A conductor is provided so as to surround the passage including on the minute gap, and the passage is a gap having a predetermined width extending in a longitudinal direction of the laser tube at a contact portion with the laser tube. The laser oscillation device according to claim 1, wherein: 5. The laser oscillation device according to claim 4, wherein the gap is filled with a dielectric. 6. The laser oscillation device according to claim 4, wherein the width of the gap is an integral multiple of a half wavelength of an electromagnetic wave introduced from the waveguide. 7. The air gap according to claim 4, wherein only the tip portion is narrowed, and the gap has a slit shape extending in a longitudinal direction of the laser tube at a contact portion with the laser tube. The laser oscillation device according to any one of claims 1 to 6. 8. The air gap is widened only in the vicinity of a tip portion thereof, and has a width substantially equal to a wavelength or a half wavelength of an electromagnetic wave introduced from the waveguide. The laser oscillation device according to claim 4. 9. The gap has a width in the vicinity of a tip portion thereof.
The laser oscillation device according to any one of claims 4 to 7, wherein the laser oscillation device has a different value along the longitudinal direction of the gap, reflecting an intensity distribution of the electromagnetic wave emitted from the minute gap. . 10. The dielectric lens according to claim 1, wherein a dielectric lens having a curved surface symmetrical with respect to the minute gap is provided in at least an upper layer of the minute gap in the passage. 2. The laser oscillation device according to claim 1. 11. The laser oscillation device according to claim 1, wherein a dielectric lens is filled in the waveguide. 12. The method according to claim 12, wherein the laser gas is Kr, Ar, Ne.
Any of the preceding claims, characterized in that an excimer laser oscillating apparatus for a mixed gas of at least one inert gas, or the at least one inert gas and F ₂ gas selected from 2. The laser oscillation device according to claim 1. 13. A light source for emitting illumination light.
13. A laser oscillation device according to any one of claims 12, a first optical system that irradiates a reticle on which a predetermined pattern is formed with illumination light from the laser oscillation device, and a surface to be irradiated with illumination light via the reticle. To irradiate the second
An exposure apparatus, comprising: an optical system, wherein a predetermined pattern of the reticle is projected onto the surface to be irradiated to perform exposure. 14. A step of applying a photosensitive material to a surface to be irradiated, and a step of exposing a predetermined pattern to the surface to be irradiated with the photosensitive material using the exposure apparatus according to claim 13. Developing the photosensitive material to which the predetermined pattern has been exposed. 15. The method according to claim 14, wherein the surface to be irradiated is a wafer surface, and a semiconductor element is formed on the wafer surface.