JPH1126856A - Bending mechanism for reflection-type waveform selecting element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain laser light having a narrow stable spectral line width so that the wave surface of the laser light may be corrected by providing supporting mechanisms which respectively support both end sections of a reflection-type wavelength selecting element and a pressing mechanism which presses the central part of the wavelength selecting element from the backside. SOLUTION: When a moving block 28 is moved toward a grating 9 by turning the knob 26 of a micrometer 25, the front face of the grating 9 can be deformed in the projecting direction, because a pressing force F is applied to the central part of the grating 9 from the backside through a spring 30 and a moving block 29. Therefore, fine wave-surface adjustment can be made by adjusting the pressing force F to an arbitrary value. In addition, since the grating 9 is supported by supporting members 21 and 23 at four corners by avoiding the central parts 31 at the left and right end sections on the front face of the grating 9, the grating 9 can be supported without sacrificing the resolution the grating 9 itself has.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflection type wavelength selection element for correcting the wavefront of laser light emitted from the reflection type wavelength selection element by bending a reflection type wavelength selection element constituting one of the resonators. Related to the bending mechanism.

[0002]

2. Description of the Related Art Use of an excimer laser as a light source of a stepper for manufacturing a semiconductor device has attracted attention. This is because the excimer laser has a short wavelength, and the light exposure limit is 0.3 mm.
It can be extended to 5 μm or less, the depth of focus is deeper than the conventional mercury lamp g-line and i-line at the same resolution, the numerical aperture (NA) of the lens can be small, and the exposure area can be reduced. This is because many excellent advantages such as large size and large power can be expected.

However, when this excimer laser is used as a light source of a semiconductor exposure apparatus, the material of an optical system lens that can be manufactured at the wavelength of an excimer laser (the wavelength of a KrF excimer laser is 248 nm and that of an ArF excimer laser is 193 nm) is used. There is only quartz material (CaF2
Processing is difficult), and a single synthetic quartz material cannot have the function of chromatic aberration.

For example, in the case of natural oscillation light of a KrF excimer laser, the spectral line width is as wide as 300 pm, and the chromatic aberration of the lens of the exposure apparatus cannot be neglected as it is, and it is impossible to obtain a sufficient resolution for the exposure result. Can not.

Therefore, when an excimer laser is used as a light source of a semiconductor exposure apparatus, a wavelength selection element such as an etalon or a grating and a prism is arranged in a laser resonator to narrow a band of a laser beam.

By the way, in the optical resonator, the wavefront of the laser light has divergence (spread) and curvature due to various causes.

For example, when a slit is arranged in a resonator, light after passing through the slit becomes a spherical wave due to diffraction by the slit.

Further, the wavefront may be distorted due to the aberration of the optical element itself disposed in the resonator. For example, in a transmission type optical element such as a prism expander used as a band narrowing element, (a) the internal refractive index distribution is not completely uniform, and (b) the polished surface of the prism is distorted. The wavefront of the laser beam passing through this optical element has a convex or concave curvature.

[0009] When laser light having a wavefront having such a curvature is incident on a grating having a flat shape, the wavelength selection performance by the grating is degraded. In other words, when the incident wavefront of the laser beam on the grating has a curvature, the laser beam is incident on each groove of the grating at a different angle, so that the wavelength selection characteristics of the grating are reduced and the band is narrowed. The spectral line width of the laser light is increased.

[0010] Therefore, in USP-5095492, the above-mentioned problem is dealt with by bending the grating itself so as to coincide with the wavefront of the laser beam incident on the grating.

That is, as shown in FIG. 20, a narrow-band excimer laser according to the prior art includes a front mirror 100, a laser chamber 101, and an aperture 10 as shown in FIG.
2. It has a beam expander 103, a mirror 104, and a grating 105, and further uses a curvature generator as shown in FIG. 21 to bend the grating 105 in accordance with the curvature of the wavefront incident on the grating 105.

In the curvature generator shown in FIG. 21, both ends of a grating 105 are mounted on a mount 1 via balls 106.
07, these mounts 107 are connected to a pressure plate 109 via a spring 108, one end of a bolt screw 110 is screwed to the pressure plate 109, and the other end is a grating 105.
22 is screwed into a nut 111 joined to the back surface of the central part of the grating 105. By pulling the central part of the grating 105 toward the pressure plate by rotation of the bolt screw 110, the grating 105 has a concave surface as shown in FIG. A curvature is generated.

In this prior art, an appropriate grating tension is set in advance in accordance with the spectral line width of the laser beam, and the grating tension corresponds to the value detected by the spectral line width detection sensor 112 based on this setting relationship. The motor 11 is set to the set tension value.
3 is driven to rotate the bolt screw 110.

[0014]

However, according to the above prior art, the grating 105 can be adjusted to a concave surface, but there is a problem that the grating 105 cannot be formed to a convex surface.

That is, an optical element such as a prism or a grating is not always manufactured in an ideal state, and there is considerable manufacturing variation depending on the element. Therefore, there is a beam expander 103 whose transmitted wavefront is concave or convex depending on the type, and a grating 103 whose diffracted wavefront is concave or convex.
For this reason, depending on the state of the wavefront transmitted through the beam expander 103 or the state of the diffracted wavefront of the grating 105, it is necessary to form the grating 105 into a convex surface to perform the wavefront correction. Correction was not possible.

In the above prior art, the grating 1
05 is a simple mechanism that supports both ends and pulls one point at the center, the shape of the grating 105 does not become a concave surface having a smooth curvature, but has a bending point as shown in FIG. When the plane wavefront was incident on the conventional grating, the diffraction wavefront had a substantially triangular shape as shown in FIG. 23.

In the future, in order to increase the resolution of the lens of the exposure apparatus to 0.25 μm or less, it is required to further increase the numerical aperture NA of the lens. growing. Therefore, it is expected that the spectral line width of the laser beam required from the exposure apparatus will be 0.4 pm or less.

In order to realize such an extremely narrow spectral line width, precise fine adjustment of the wavefront is required. Can not.

The present invention has been made in view of such circumstances, and provides a bending mechanism of a reflection-type wavelength selection element capable of correcting a laser wavefront that can obtain a laser beam having a narrow and stable spectral line width. The purpose is to do.

[0020]

SUMMARY OF THE INVENTION According to the present invention, a reflector for correcting the wavefront of laser light emitted from a reflective wavelength selecting element by bending a reflective wavelength selecting element constituting one of the resonators. In the bending mechanism of the wavelength selecting element, a supporting mechanism for supporting both ends of the reflective wavelength selecting element and a pressing mechanism for pressing a substantially central portion on the back surface of the reflective wavelength selecting element are provided.

According to the invention, since both ends of the reflection-type wavelength selection element such as a grating are supported and a substantially central portion of the back surface thereof is pressed, the reflection-type wavelength selection element is formed into a convex surface. This makes it possible to correct the wavefront emitted from the reflective wavelength selection element in the convex direction.

According to the present invention, there is provided a bending mechanism of a reflection-type wavelength selection element for correcting a wavefront of laser light emitted from the reflection-type wavelength selection element by bending a reflection-type wavelength selection element constituting one of the resonators. A support mechanism for supporting both end portions of the reflection-type wavelength selection element, and a mechanism for pressing or pulling a plurality of different one-dimensional positions on the back surface of the reflection-type wavelength selection element.

According to this invention, the reflective wavelength selecting element is formed into a concave or convex surface by pressing or pulling a plurality of locations on the back surface of the reflective wavelength selecting element, so that a smooth and almost constant curvature is obtained. This makes it possible to obtain a concave or convex surface, and according to the present invention, it is possible to efficiently and stably output laser light having a very narrow spectrum. In addition, precise and complicated wavefront adjustment becomes possible.

According to the present invention, there is provided a bending mechanism of a reflection-type wavelength selection element for correcting a wavefront of laser light emitted from the reflection-type wavelength selection element by bending a reflection-type wavelength selection element constituting one of the resonators. And a support mechanism for supporting a substantially central portion of the reflection-type wavelength selection element at one or a plurality of locations, and a mechanism for pressing or pulling the vicinity of both ends on the back surface of the reflection-type wavelength selection element.

According to the present invention, the central portion of the reflection type wavelength selection element such as a grating is supported at one or a plurality of positions, and both ends on the back surface thereof are pressed or pulled. Can be molded into a convex or concave surface.

[0026]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 2 shows a resonator configuration of an excimer laser provided with a grating to which the present invention is applied. FIG.
2A shows the overall configuration of the resonator, and FIG. 2B shows the internal configuration of the band narrowing module 6 provided in the resonator.

In FIG. 2, a laser chamber 2 of an excimer laser 1 has a discharge electrode 3 in which an anode and a cathode are arranged opposite to each other in a direction perpendicular to the plane of the drawing, and a halogen gas filled in the laser chamber 2 is provided. A laser gas, such as a rare gas or a buffer gas, is excited by the discharge between the discharge electrodes 3 to perform laser oscillation.

Windows 4 are provided at both laser emission ports of the laser chamber 2. Laser chamber 2
A slit 7 for limiting the beam width is provided between the laser beam 2 and the front mirror 5 and between the laser chamber 2 and the band narrowing module 6.

In this case, the narrowing module 6 comprises a beam expander 8 and a grating 9 which is an angular dispersion type wavelength selecting element. The beam expander 8 includes two prisms 8a and 8a, as shown in FIG.
b, the beam width of the incident laser beam is enlarged and the laser beam is incident on the grating 9.

That is, in the case of the embodiment shown in FIG. 1, an optical resonator is formed between the front mirror 5 and the grating 9. In the structure shown in FIG. , And into the narrowing module 6, and the beam width is expanded by the beam expander 8. Further, the expanded laser light is incident on the grating 9 and diffracted, so that only the laser light of a predetermined wavelength component is turned back in the same direction as the incident light. The laser beam turned back by the grating 9 is incident on the laser chamber 2 after the beam width is reduced by the beam expander 8.

A part of the laser light amplified by passing through the laser chamber 2 is extracted as output light via the front mirror 5, and the rest is returned to the laser chamber 2 and amplified again.

Here, the grating 9 shown in FIG. 2 is provided with a support mechanism for supporting both ends thereof, and a mechanism for pressing or pulling the back surface at one or more points. Can be bent (or corrected) arbitrarily, whereby the wavefront aberration of the diffracted wavefront at the grating 9 can be corrected.

That is, in the configuration shown in FIG. 2, the diffraction light intensity becomes maximum when the wavelength of the laser beam incident on the grating 9 is λ, the incident angle is θ, and the groove interval distance of the grating is d. , When the following equation is satisfied.

M · λ = 2 · d · sin θ (1) When both sides of the above equation (1) are differentiated and deformed by λ, the following equation (2) is obtained.

Dθ / dλ = (m · tan θ) / (2 · d · sin θ) (2) From the above equations (1) and (2), the following equation (3) is obtained.

Dθ / dλ = tan θ / λ (3) From the equation (3), the following equation (4) is established.

Δλ = (λ / tan θ) · Δθ (4) In the above equation (4), Δλ is the spectral line width, and Δθ is the divergence angle of the laser beam incident on the grating.

Here, correcting the wavefront aberration of the beam expander 8 and the grating 9 has the same effect as making Δθ of the above equation (4) substantially zero, so that the left side of the equation (4) is thereby obtained. That is, the spectral line width Δλ can be minimized.

That is, in the configuration shown in FIG. 2, if the surface shape of the grating 9 is precisely adjusted by the bending mechanism provided in the grating 9, the manufacturing failure of the beam expander 8 or the manufacturing failure of the grating 9 can be reduced. Alternatively, the distortion of the wavefront of the diffracted light of the grating 9 due to the beam divergence of the laser light can be corrected, whereby a very narrow spectral line width (0.
4 pm or less) can be efficiently output.

Hereinafter, various specific structural examples of the bending mechanism of the grating 9 will be described.

[First Embodiment] FIG. 1 shows a first embodiment of the bending mechanism of the grating 9.

FIG. 1 (a) is a plan view, and FIG. 1 (b) is A in FIG. 1 (a).
FIG. 1 (c) is a front view of FIG. 1 (a) viewed from the direction of arrow q.

In the first embodiment, by supporting both ends of the grating 9 and pressing a point at the center of the back surface of the grating 9, the
Can be corrected from a concave surface to a flat surface or from a flat surface to a convex surface.

In FIG. 1, the grating 9 is
A pair of lower support members 21 fixed to the table 20 and a pair of upper support members 23 fixed to the support frame 22 on the surface side of the grating 9 (grooves are formed). End) is supported at four points at both ends. That is, in this case, both ends of the grating 9 are regulated by the support members 21 and 23 so as not to move forward.

On the other hand, on the rear side of the grating,
A fixing member 24 is attached to the top of the micrometer 0, and a micrometer head 25 is attached to the fixing member 24. The micrometer head 25 is obtained by removing the U-shaped frame portion of the micrometer for measuring the length, and can turn the spindle 27 in the front-rear direction with high precision by turning the knob 26.

The spindle 2 of the micrometer head 25
A moving block 28 is attached to the tip of 7,
The moving block 28 moves in the front-rear direction with the movement of the spindle 27.

A moving block 29 is fixed to the center of the back surface of the grating 9, and two moving blocks 28,
An elastic body 30 such as a spring is interposed between 29. The end of the spring 30 on the moving block 29 side is fixed to the moving block, but the end on the moving block 28 side is free.

In the first embodiment, when the moving block 28 is advanced in the direction of the grating 9 by turning the knob 26 of the micrometer 25, the center of the grating 9 is The pressing force F is applied, so that the shape of the front surface of the grating 9 can be deformed in the convex direction.

According to this embodiment, the center of the back surface of the grating 9 is pressed via the spring 30 by using the micrometer head 25. (1) The grating 9 is bent stably with a constant force. (2) By setting the scale of the micrometer head 25 to an appropriate value, the pressing force F can be adjusted to an arbitrary value with high accuracy, and fine wavefront adjustment can be performed. There is.

According to the above embodiment, the supporting member 2
Since the front and back sides of the grating 9 are supported at the four corners of the grating 9 by means of 1, 23, the diffraction function as a grating also works at the left and right ends.
The grating 9 can be supported without lowering its own resolution. In the case where the resolution may be reduced, the middle part 3 at the left and right ends of the grating may be used.
1, the grating 9 may be supported, and the entire left and right ends may be supported by a support member.

FIG. 3A shows an incident wavefront (solid line) and a diffracted wavefront (broken line) before the grating 9 is bent by the bending mechanism. In this case, the diffracted wavefront has a concave shape. FIG. 3B shows an incident wave front (solid line) and a diffracted wave front (dashed line) when the center of the grating 9 is protruded by the bending mechanism of the first embodiment. It can be seen that the wavefront shape is in the shape of a letter, but is close to a plane wavefront.

[Second Embodiment] FIG. 4 shows a second embodiment of the bending mechanism of the grating 9.

In the second embodiment, a pressure plate 33 is added to the first embodiment. The pressure plate 3 has a concave shape having protrusions at both ends, and is in contact with the back surface of the grating 9 at two positions at both ends.

Therefore, in the second embodiment, the pressing force F applied to one point on the back surface of the pressure plate 33 via the moving block 29 is dispersed by the leverage principle and pushed through both ends of the pressure plate 33. Pressures F1 and F2 are applied to the back of the grating 9.

F1 = {b / (a + b)} × F F2 = {a / (a + b)} × F In this case, by adjusting the position of the pressure plate 33 in the left-right direction, an arbitrary position on the back surface of the grating 9 can be obtained. Pressing forces F1 and F2 can be applied to two points.

Therefore, in this embodiment, the grating 9 can be bent into a more complicated and smooth shape as compared with the first embodiment, and the laser wavefront can be more finely and precisely adjusted. Will be possible.

FIG. 5A shows an incident wavefront (solid line) and a diffracted wavefront (broken line) before the grating 9 is bent by the bending mechanism. In this case, the diffracted wavefront has a concave shape. FIG. 5B shows an incident wavefront (solid line) and a diffracted wavefront (dashed line) when the grating 9 is projected by the bending mechanism of the second embodiment. In this case, the diffracted wavefront is the first wavefront. It does not have a W-shaped wavefront shape as in the embodiment, but has a substantially plane wavefront.

In this embodiment, the pressure plate 33 may be configured so that three or more points on the back surface of the grating 9 can be pressed.

[Third Embodiment] FIG. 6 shows a third embodiment of the bending mechanism of the grating 9.

In the third embodiment, plunger screw mechanisms 34 and 35 are added to the second embodiment.

The plunger screw mechanisms 34 and 35 are disposed at both ends on the back surface of the grating 9, and the detailed configuration is as shown in FIG.

At both ends on the back side of the grating 9, back side support members 36 are provided, respectively. A plunger screw 37 whose outer periphery is threaded is screwed to these back side support members 36. ing. Plunger screw 3
7, a piston member 39 is provided via a spring 38.

That is, in this case, the plunger screw 37
By turning, the pressing force is applied to both ends on the back surface of the grating 9 via the spring 38 and the piston member 39.

Therefore, in this embodiment, four points on the back surface of the grating 9 can be pressed with an arbitrary pressing force, and the grating 9 can be bent into a more complicated and smooth shape as compared with the previous embodiment. And the laser wavefront can be more finely and precisely adjusted.

In this embodiment, since the plunger screw mechanisms 34 and 35 press the both sides of the grating 9, they also have the effect of suppressing the vibration of the grating 9. Therefore, even when the grating 9 is rotated for wavelength control, the vibration is reduced, and the variation of the spectral line width due to the vibration can be reduced.

[Fourth Embodiment] FIG. 8 shows a fourth embodiment of the bending mechanism of the grating 9.

FIG. 8A is a plan view, and FIG.
FIG. 8 (c) is a front view of FIG. 8 (a) viewed from the direction of arrow q.

In the fourth embodiment, the shape of the front surface of the grating 9 is corrected to a concave surface or a convex surface by supporting both ends of the grating 9 and pressing and pulling a point at the center of the back surface of the grating 9. Have to be able to.

In FIG. 8, the center of the grating 9 is sandwiched by a U-shaped holder 40. The U-shaped holder 40 has a groove 4 formed in the center of the base 20.
1 can slide forward and backward.

On the other hand, both ends of the grating 9 are supported by supporting members 21 and 23 at four corners on the front surface. The back surfaces of both ends of the grating 9 are supported by a back support member 36. That is, in this case, both ends of the grating 9 are fixed on both the front and back sides.

An elastic body 42 such as a pressing spring is connected to the back side of the U-shaped holder 40, and an elastic body 44 such as a pulling spring is connected via a pin 43. A pair of extension springs 44 are provided on the left, right, up and down, and a total of four are provided.

The other end of the push spring 42 is connected to a moving block 45.
Is in contact with The moving block 45 is provided with a pin 43 '.
Is connected to the extension spring 44 via the pull-down spring. Guide members 57 are provided on both sides of the moving block 45 to guide the sliding motion of the moving block 45 in the front-rear direction.

In order to slide the moving block 45 forward and backward, a push bolt 46 and a pull bolt 47 are used.
Is provided. The push bolt 46 and the pull bolt 47 are supported by a fixing block 48 fixed on the base 20. 49 is a lock nut for locking the push bolt 46.

FIG. 9A shows a conceptual configuration of the push bolt 46 and the pull bolt 47. In FIG. 9, the lock nut 4
9 is omitted.

That is, a screw is formed on the outer periphery of the push bolt 46, and the push bolt 46 is screwed with the fixed block 48 by this screw. Also, push bolt 4
6 and the moving block 45 are free, and the moving block 45 can be pressed by the tip of the push bolt 46. The front-rear position of the push bolt 45 is locked by fastening a lock nut 49.

On the other hand, a pull bolt 47 penetrates through the push bolt 46, and the pull bolt 47 is screwed to the moving block 45 at its tip.

With reference to FIG. 9, the operation of pressing the center of the back surface of the grating 9 to form the front surface of the grating 9 into a convex shape in such a configuration will be described.

First, the lock nut 49 and the pull bolt 47
To make the push bolt 46 movable with respect to the fixed block 48 (FIG. 9A). Next, the push bolt 46
To move the push bolt 46 forward. The movement block 45 is pushed by this movement, and the movement block 45 is moved.
Slides forward (FIG. 9 (b)). The sliding of the moving block 45 is performed by the U-shaped holder 4 via the pressing spring 42.
0, whereby the U-shaped holder 41 is moved forward along the groove 41. As a result, grating 9
Is displaced forward, and the grating 9 can be formed in a convex shape.

Next, the operation of pulling the center of the back surface of the grating 9 to form the front surface of the grating 9 into a concave shape will be described with reference to FIG.

First, when the pull bolt 47 is turned so as to be pulled out from the moving block 45 in the state of FIG. 9A, only the pull bolt 47 is slid backward with the push bolt 46 fixed to the fixed block 48. (FIG. 9 (c)). In this state, the lock nut 49 is loosened so that the push bolt 46 can be moved with respect to the fixed block 48. Next, the push bolt 46 is turned so as to be separated from the moving block 45 to form a gap between the tip of the push bolt 46 and the moving block 45 (FIG. 9D). Next,
The push nut 46 is fixed to the fixing block 48 by fastening the lock nut 49.

In this state, when the pull bolt 47 is turned so as to be embedded in the moving block 45, as shown in FIG. 9 (e), until the head of the pull bolt 47 and the head of the push bolt 46 abut on each other. Moves forward. When the pull bolt 47 is turned so as to be embedded in the moving block 45 even after the head of the pull bolt 47 and the head of the push bolt 46 are in contact with each other, the pull bolt 47 does not move forward even if it is turned. The moving block 45 is slid (rearward) toward the fixed block 48 as shown by an arrow d in FIG.

The rearward sliding of the moving block 45 is transmitted to the U-shaped holder 40 via the pulling spring 44,
Thereby, the U-shaped holder 41 is moved rearward along the groove 41. As a result, the central portion of the grating 9 is displaced rearward, and the grating 9 can be formed in a concave shape.

FIG. 5A shows the incident wavefront (solid line) and the diffracted wavefront (broken line) before the grating 9 is bent by the bending mechanism. In this case, the diffracted wavefront has a convex shape. FIG. 5 (b) shows the incident wavefront (solid line) and the diffracted wavefront (dashed line) when the grating 9 is made concave by pulling the center of the grating 9 by the bending mechanism of the fourth embodiment. The diffracted wavefront is almost flat.

[Fifth Embodiment] FIG.
A fifth embodiment of the bending mechanism shown in FIG.

In the fifth embodiment, the pressing mechanism using the micrometer head shown in the first embodiment shown in FIG. 1 is arranged at three places in the longitudinal direction of the grating 9 (the direction in which the grooves are arranged). We are trying to establish. The details of each pressing mechanism are the same as in the embodiment of FIG. In this case, since only the mechanism for pressing the back surface of the grating 9 is provided, both ends of the grating 9 are supported only on the front surface side.

In this embodiment, an elongated hole 50 for adjusting the position of the pressing mechanism is formed on the base 20 along the longitudinal direction of the grating 9. That is, FIG.
As shown in FIG. 2, two bolts 51 are screwed into the fixing member 24 supporting the micrometer head 25, and a fastening piece 52 is attached to the tip of each bolt 51.
Are screwed into the elongated hole 50.

Therefore, each micrometer head 25
To adjust the position of the grating 9 in the longitudinal direction, the bolt 51 is loosened and the fixing member 24 is slid to the desired position along the elongated hole 50. When the position is determined, the fixing member 24 is fixed to the base 20 by tightening the bolt 51 by the fastening piece 52.

As described above, in this embodiment, arbitrary multipoint positions along the longitudinal direction of the grating 9 can be pressed from the back, and each pressing force can be arbitrarily set by the micrometer head 25. Even if the diffraction wavefront of the grating before wavefront correction has a very complicated wavefront shape as shown in FIG. 13 (a), it is corrected and formed into a substantially plane wavefront as shown in FIG. 13 (b). be able to.

[Sixth Embodiment] FIG.
6th Example about the bending mechanism of FIG.

In the sixth embodiment, both ends of the grating 9 are supported on the back side of the grating 9 by the back support member 36, and a point at the center of the back surface of the grating 9 is pulled so that the front surface of the grating 9 is formed. It can be formed into a concave surface.

In FIG. 14, a pull plate 60 is bonded to the center of the back surface of the grating 9 with an adhesive, and a plurality of pull springs 44 are attached to the pull plate 60.
Are connected. The other end of the extension spring 44 is connected via a pin 61 to a slide member 62 having a tapered surface. The slide member 62 slides forward and backward along a guide unit 63 provided on the table 20.

A fixing member 64 is mounted on the base 20, and the micrometer head 25 is mounted on the fixing member 64. Micrometer head 2
A moving block 65 having a tapered surface is attached to the tip of the spindle 27 of the fifth block.
And the tapered surface of the slide member 62 are in contact with each other.

According to this embodiment, when the knob 26 of the micrometer head 25 is turned to slide the moving block 65 in the direction of the arrow e1, the slide member 62 slides in the direction of the arrow e2 by the action of the tapered surface. As a result, the center of the back surface of the grating 9 is
4 will be pulled through the grating 9
Can be formed into a concave surface.

According to such a configuration, it is not necessary to secure a space for the micrometer head 63 behind the grating 9, so that the device configuration can be made compact.

In this embodiment, the micrometer head 25 and the moving block 65 are arranged so that the knob 26 of the micrometer head 25 can be turned on the side of the table 20. The micrometer head 25 and the moving block 65 may be arranged so that the knob 26 can be turned below or above the table 20.

[Seventh Embodiment] FIG.
7th Example about the bending mechanism of FIG.

In the seventh embodiment, a pull plate 66 is added to the sixth embodiment shown in FIG. Three points of the pull plate 66 are adhered to the back surface of the grating 9.

Therefore, in the seventh embodiment, the pulling force applied to the pulling plate 66 via the pulling spring 44 is dispersed and pulls the back surface of the grating 9 at three points. Therefore, in this embodiment, a grating having a smoother concave surface can be created as compared with the sixth embodiment.

[Eighth Embodiment] FIG.
An eighth embodiment of the bending mechanism shown in FIG.

In the eighth embodiment, the pulling mechanism 70 using the micrometer head is disposed at three positions in the longitudinal direction of the grating 9 (the direction in which the grooves are arranged).

As in the fifth embodiment shown in FIG. 11, a slot 50 for adjusting the position of the pulling mechanism 70 is formed on the base 20, and three slots are formed in the same manner as in the fifth embodiment. The position of the pulling mechanism 70 along the longitudinal direction of the grating 9 can be arbitrarily adjusted.

[Ninth Embodiment] FIG.
A ninth embodiment of the bending mechanism shown in FIG.

FIG. 17A is a plan view, and FIG.
17A is a cross-sectional view taken along line AA, and FIG. 17C is a front view of FIG. 17A viewed from the direction of arrow q.

In the ninth embodiment, the bending adjustment of the grating 9 accommodated in the narrowing box can be performed from outside the narrowing box, and the grating is provided in the narrowing box. And the region where the bending mechanism described above is disposed, is completely spatially and optically separated. In this case, the center of the back surface of the grating 9 can be pressed, so that the grating 9 can be formed into a convex surface.

In FIG. 17, the front side of the grating 9 is supported at four points at both ends by supporting members 21 and 23.

On the other hand, on the rear side of the grating,
A pair of guide blocks 80 is provided on 0, and a moving block 81 slides between the guide blocks 80. The moving block 81 is formed with a tapered surface 82, and the spindle 27 of the micrometer head 25 is in contact with the tapered surface 82. Therefore, when the spindle 27 of the micrometer head 25 slides in the direction of arrow g1, the moving block 81 slides in the direction of arrow g2.

A moving block 83 is fixed to the center of the back surface of the grating 9, and the two moving blocks 83
A spring 84 is interposed between 81.

Therefore, in this embodiment, when the knob 26 of the micrometer 25 is turned to advance the moving block 81 in the direction of the grating 9, the spring 84 and the moving block 83 move to the center of the grating 9 from the back. The pressing force F is applied, whereby the shape of the grating 9 can be deformed in the convex direction.

Here, the table 20 of the bending mechanism is shown in FIG.
As shown in FIG. 2, the narrowing box attached to the bottom plate 85 of the narrowing box corresponds to the narrowing module 6 shown in FIG. 2, and optical elements such as the grating 9 and the beam expander are provided. Is housed. The inside of the band narrowing box is always filled with a purge gas (such as N2), and the box must be isolated from the external atmosphere as much as possible in order not to lower the performance of band narrowing.

For this reason, in FIG. 17, separating walls 86 and 87 are attached to the bottom plate 85 of the band narrowing box, and only the spindle portion 27 of the micrometer head 25 is mounted inside the band narrowing box by the separating walls 86 and 87. To be accommodated. A hole 88 is formed in a portion of the bottom plate 85 of the narrowing box to which the separating walls 86 and 87 are attached, so that the knob 26 of the micrometer head 25 can be turned from the outside of the narrowing box.

Further, inside the narrowing box, a space 91 where the spindle 27 of the micrometer head 25 and the spindle 27 of the moving block 81 are in contact is formed with a lid 89, a rear wall 90, 1. The pair of guide blocks 80 are structurally and optically isolated from the space in which the optical elements of the narrowing box are present.

Therefore, dust from the sliding portion between the moving block 81 and the spindle 27, or impure gas due to light irradiation of the lubricant used for the micrometer head 25, etc., is in the space where the optical element of the narrowing box exists. Can be reliably suppressed.

The lid 89 also functions to restrict the upward movement (in the direction of arrow g1) of the moving block 81.

By the way, the technique of disposing the adjusting mechanism for adjusting the pressing force of the pressing mechanism, which is performed in this embodiment, outside the narrowing box is described in each of the above-described embodiments and the tenth embodiment which will be described later. You may make it apply to an Example.

Further, in each of the above-described embodiments and a tenth embodiment described below, a separating wall for separating an area occupied by a part of the pressing mechanism and an area where the optical element is present is provided in the narrowing box. You may make it apply to an example.

[Tenth Embodiment] FIG. 18 shows a tenth embodiment of the bending mechanism of the grating 9. FIG.
FIG. 18B is a sectional view taken along line AA of FIG.

In each of the above embodiments, both ends of the grating 9 are supported. In the tenth embodiment, the center of the back surface of the grating 9 is supported by the support member 92. The support member 92 is fixed on the base 20 and is adhered to the back surface of the grating 9 with an adhesive.

At the vicinity of both ends on the back surface of the grating 9, the above-mentioned pressing and pulling mechanism by the micrometer head is provided, so that both ends of the grating 9 can be pressed and pulled.

In this embodiment, the central portion of the back surface of the grating 9 may be supported at a plurality of positions.

[Modification] In the above embodiment, the wavefront correction is performed by bending the grating 9 of the band narrowing module by a bending mechanism. However, the present invention can be applied to a resonator structure as shown in FIG. Can be applied.

In the resonator structure shown in FIG. 19, the wavelength is selected by the dispersive prism 95, and the rear mirror 96 is arranged in place of the grating 9. Therefore, in this case, the bending mechanism as described in the above embodiment may be attached to the rear mirror 96, and the wavefront correction may be performed by bending the rear mirror 95.

Further, the present invention may be applied to other resonator structures such as a polarization coupling type resonator, an injection lock type, and an unstable resonator.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a resonator structure to which the present invention is applied;

FIG. 3 is a diagram showing an example of wavefront correction according to the first embodiment.

FIG. 4 is a diagram showing a second embodiment of the present invention.

FIG. 5 is a diagram showing an example of wavefront correction according to a second embodiment.

FIG. 6 is a diagram showing a third embodiment of the present invention.

FIG. 7 is a view showing a plunger screw mechanism used in a third embodiment.

FIG. 8 is a diagram showing a fourth embodiment of the present invention.

FIG. 9 is a diagram showing an operation procedure using a push-pull bolt used in the fourth embodiment.

FIG. 10 is a diagram showing an example of wavefront correction according to a fourth embodiment.

FIG. 11 is a diagram showing a fifth embodiment of the present invention.

FIG. 12 is a diagram showing a position adjusting mechanism used in a fifth embodiment.

FIG. 13 is a diagram showing an example of wavefront correction according to a fifth embodiment.

FIG. 14 is a diagram showing a sixth embodiment of the present invention.

FIG. 15 is a diagram showing a seventh embodiment of the present invention.

FIG. 16 is a diagram showing an eighth embodiment of the present invention.

FIG. 17 shows a ninth embodiment of the present invention.

FIG. 18 is a diagram showing a tenth embodiment of the present invention.

FIG. 19 is a diagram showing a resonator structure in which another reflection-type wavelength selection element to which the present invention is applied is arranged.

FIG. 20 is a diagram showing a conventional technique.

FIG. 21 is a diagram showing a conventional technique.

FIG. 22 is a diagram showing a conventional grating.

FIG. 23 is a diagram for explaining a problem caused by the related art.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Excimer laser apparatus 2 ... Laser chamber 3 ... Discharge electrode 4 ... Window 5 ... Output mirror 6 ... Narrowing module 7 ... Slit 8 ... Beam expander 9 ...
Grating 20: table 21, 23: support member 22
... Support frame 24 ... Fixing member 25 ... Micrometer head
26: knob 27: spindle 28, 29: moving block
Reference Signs List 30 push spring 33 pressure plate 34, 35 plunger screw mechanism 36 support member 37 plunger screw 3
8 Spring 39 Piston member 40 U-shaped block 41
… Groove 42… Press spring 43, 43 ′, 61… Pin 44
... pull spring 45 ... moving block 46 ... push bolt 47 ... pull bolt 48 ... fixed block 49 ... lock nut 50 ...
Slot 51 51 Bolt 52 Tightening piece 57 Guide member 60 Pull plate 62 Slide member 63
Guide unit 64 ... Fixing member 65 ... Move block 66 ...
Pull plate 70: Pull mechanism 80: Guide block 81
... moving block 82 ... tapered surface 83 ... moving block 84 ...
Spring 85: Bottom plate of band narrowing box 86, 87 ... Isolation wall 88 ... Hole 89 ... Lid body 90 ... Rear wall 91 ... Space 92 ... Support member 95 ... Dispersion prism 96 ... Rear mirror

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Osamu Wakabayashi 1200 Manda, Hiratsuka-shi, Kanagawa Prefecture, Komatsu Ltd.

Claims (22)

[Claims] 1. A bending mechanism of a reflection-type wavelength selection element for correcting a wavefront of laser light emitted from the reflection-type wavelength selection element by bending a reflection-type wavelength selection element constituting one of the resonators. A bending mechanism for a reflection-type wavelength selection element, comprising: a support mechanism for supporting both end portions of the reflection-type wavelength selection element; and a pressing mechanism for pressing a substantially central portion on the back surface of the reflection-type wavelength selection element. 2. A bending mechanism for a reflection-type wavelength selection element according to claim 1, wherein said pressing mechanism has an elastic body, and presses a substantially central portion of a back surface of said reflection-type wavelength selection element through said elastic body. 3. The reflection-type wavelength selection element is housed in a predetermined closed box, and an adjusting mechanism for adjusting the pressing force of the pressing mechanism is disposed outside the closed box. The bending mechanism of the reflection-type wavelength selection element according to claim 1, wherein: 4. A bending mechanism for a reflection-type wavelength selection element according to claim 3, wherein an isolation wall for separating said pressing mechanism and said reflection-type wavelength selection element is provided in a closed box. 5. A bending mechanism of a reflection-type wavelength selection element for correcting a wavefront of laser light emitted from the reflection-type wavelength selection element by bending a reflection-type wavelength selection element constituting one of the resonators. A bending mechanism comprising: a support mechanism for supporting both end portions of the wavelength selecting element; and a pressing mechanism for pressing a plurality of different positions in the one-dimensional direction on the back surface of the reflective wavelength selecting element. mechanism. 6. A pressure plate having a plurality of projections on a front surface thereof, the plurality of projections being provided in contact with a back surface of a reflection type wavelength selection element, and a back surface of the pressure plate. The bending mechanism of the reflection-type wavelength selection element according to claim 5, further comprising: a pressing body that presses one of the positions. 7. The bending mechanism according to claim 6, wherein an elastic body is interposed between the pressing body and the pressure plate. 8. A bending mechanism for a reflection-type wavelength selection element according to claim 5, wherein said pressing mechanism comprises a plurality of pressing bodies disposed at different positions in a one-dimensional direction on a back surface of said reflection-type wavelength selection element. . 9. A bending mechanism for a reflection-type wavelength selection element according to claim 8, wherein an elastic body is interposed between said plurality of pressing bodies and a back surface of said reflection-type wavelength selection element. 10. The bending mechanism according to claim 8, wherein said pressing mechanism has a position adjusting mechanism capable of variably adjusting the positions of said plurality of pressing bodies. 11. The reflection type wavelength selection element is housed in a predetermined closed box, and an adjusting mechanism for adjusting the pressing force of the pressing mechanism is disposed outside the closed box. The bending mechanism of the reflection-type wavelength selection element according to claim 5, wherein: 12. A bending mechanism for a reflection-type wavelength selection element according to claim 11, wherein an isolation wall for separating said pressing mechanism and said reflection-type wavelength selection element is provided in a closed box. 13. A bending mechanism of a reflection-type wavelength selection element for correcting a wavefront of laser light emitted from the reflection-type wavelength selection element by bending a reflection-type wavelength selection element constituting one of the resonators. A bending mechanism for the reflection-type wavelength selection element, comprising: a support mechanism for supporting both ends of the wavelength-selection element; and a tension mechanism for pulling a plurality of different positions in the one-dimensional direction on the back surface of the reflection-type wavelength selection element. . 14. A pulling plate having a plurality of protrusions on a front surface thereof, the plurality of protrusions being provided on a back surface of a reflection type wavelength selection element, and a pulling plate provided on the pulling plate. 14. The bending mechanism of the reflection-type wavelength selection element according to claim 13, further comprising: a tension member that pulls one position on the back surface. 15. The bending mechanism according to claim 14, wherein an elastic member is interposed between the tension member and the pull plate. 16. The bending mechanism for a reflection-type wavelength selection element according to claim 13, wherein the tension mechanism includes a plurality of tension bodies disposed at different positions in a one-dimensional direction on a back surface of the reflection-type wavelength selection element. . 17. An elastic body is interposed between said plurality of tension bodies and a back surface of said reflection-type wavelength selection element.
7. The bending mechanism of the reflection-type wavelength selection element according to 6. 18. A bending mechanism for a reflection-type wavelength selection element according to claim 16, wherein said tension mechanism has a position adjustment mechanism capable of variably adjusting the positions of said plurality of tension bodies. 19. The reflection type wavelength selection element is housed in a predetermined closed box, and an adjusting mechanism for adjusting the pulling force of the pulling mechanism is disposed outside the closed box. 14. The bending mechanism of the reflection-type wavelength selection element according to claim 13, wherein: 20. A bending mechanism for a reflection-type wavelength selection element according to claim 19, wherein an isolation wall for separating said tension mechanism and said reflection-type wavelength selection element is provided in a closed box. 21. A bending mechanism of a reflection-type wavelength selection element for correcting a wavefront of a laser beam emitted from the reflection-type wavelength selection element by bending a reflection-type wavelength selection element constituting one of the resonators. A reflection mechanism, comprising: a support mechanism for supporting a substantially central portion of the wavelength selection element at one or a plurality of locations; and a mechanism for pressing or pulling the vicinity of both ends on the back surface of the reflection wavelength selection element. Bending mechanism. 22. A bending mechanism for a reflection-type wavelength selection element according to claim 1, wherein said reflection-type wavelength selection element is a grating.