JP2003158324A - Light source and light irradiator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source from which a high luminance light can be obtained efficiently through a simple arrangement. SOLUTION: A first optical fiber amplifier 131 comprising an amplification optical fiber 1351 , having a Bragg diffraction grating 139 transmitting a light being amplified and a pumping light and reducing propagation of noise light incident to optical amplification, as an amplification medium amplifies the light being amplified and utilizes amplification energy supplied as the pumping light efficiently for amplifying a signal light. The pumping light passed through the amplification optical fiber 1351 is branched through an optical branch unit 137E1 and fed to a second optical fiber amplifier 132 thus obtaining a high luminance light efficiently.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light source device and a light irradiation device, and more particularly to a light source device including an optical amplifier that amplifies light, and a light irradiation device including the light source device.

[0002]

2. Description of the Related Art Conventionally, a light irradiation device has been used for inspecting a fine structure of an object, fine processing of the object, and treatment for correction of visual acuity. For example, in a lithography process for manufacturing a semiconductor device or the like, a mask or a reticle (hereinafter,
A pattern formed on a “reticle” is transferred onto a substrate such as a wafer or a glass plate (hereinafter, appropriately referred to as “substrate” or “wafer”) coated with a resist or the like via a projection optical system. Therefore, an exposure device, which is a kind of light irradiation device, is used. As such an exposure apparatus, a static exposure type projection exposure apparatus adopting a step-and-repeat method and a scanning exposure type projection exposure apparatus adopting a step-and-scan method are mainly used. In addition, a corneal surface ablation (PRK: Photorefractive Keratectom) is used to correct vision.
y) or ablation inside the cornea (LASIK: L
Laser treatment equipment, which is a type of light irradiation equipment, is used to treat myopia and astigmatism by performing aser Intrastromal Keratomileusis).

For such a light irradiation device, many developments have been made on a light source that emits light of a short wavelength. The direction of development of such a short wavelength light source is mainly classified into the following two types. One is the development of an excimer laser light source in which the oscillation wavelength itself of the laser is a short wavelength, and the other is the development of a short wavelength light source using the generation of harmonics of an infrared or visible light laser.

Of these, along the former direction, KrF
A light source device using an excimer laser (wavelength 248 nm) was developed, and now ArF is used as a light source with a shorter wavelength.
Development of a light source device using an excimer laser (wavelength 193 nm) or the like is in progress. However, these excimer lasers have disadvantages as a light source device, such as large size and complicated maintenance of the laser due to the use of poisonous fluorine gas and high cost.

Therefore, the nonlinear optical effect of a nonlinear optical crystal, which is a method of shortening the wavelength along the latter direction, is utilized.
A method of converting long-wavelength light (infrared light, visible light) into shorter-wavelength ultraviolet light has attracted attention. As a light source device using such a method, for example, International Publication WO99 /
There is one disclosed in 46835 (hereinafter, simply referred to as "conventional example").

[0006]

In the method of shortening the wavelength using the nonlinear optical crystal as described above, the generation efficiency of the short wavelength light is determined by the generation efficiency of the nonlinear optical effect in the nonlinear optical crystal. The generation efficiency of the effect becomes higher as the luminance (including the meaning of “peak power”) of the incident target light for wavelength conversion is higher. Therefore, in order to efficiently obtain ultraviolet light, it is necessary to make high-intensity infrared light or visible light incident on the nonlinear optical crystal. Therefore, in the above-mentioned conventional example, the infrared light or the visible light having a single wavelength generated by the semiconductor laser or the like is emitted from the erbium (E
r) and other rare earth elements are added to an optical fiber amplifier having an optical fiber for amplification, and the amplified optical fiber is made incident on a nonlinear optical crystal. In such an optical fiber amplifier, pumping light is supplied to the amplification optical fiber,
By exciting the added rare earth element, an inversion distribution is formed with respect to the energy level of the outer shell electrons of the rare earth element, thereby imparting an optical amplification function to the amplification optical fiber.

However, when light of high peak power is generated by using an amplification optical fiber doped with a rare earth element,
Stimulated Raman scattering (St
imulated Raman Scattering (SRS) and four-wave mixing (F
Noise light is generated by a nonlinear optical effect such as our-Wave Mixing (FWM). Since these noise lights are also amplified in the amplification optical fiber, the amplification power of the amplification optical fiber is used for amplification of the noise light, and the amplification capacity of the amplification optical fiber is used to amplify the signal light. I couldn't use it well.

If amplification by the amplification optical fiber is made to have a high gain, spontaneous emission light (Amplified Spectral Light) is generated as noise light.
ontaneous emission (ASE) occurs. This ASE
As a result, the amplification power of the amplification optical fiber is used, and the amplification capability of the amplification optical fiber cannot be efficiently used for amplification of the signal light.

In order to reduce the non-linear optical effect (noise light due to SRS, FWM, etc.) among the above-mentioned noise lights, the amplification optical fiber is shortened and the mode field diameter (Mode Field Diameter: It is known that the reduction of the light density due to the expansion of MFD) is effective. However, when the length of the amplification optical fiber is shortened, the amplification gain is inevitably lowered.
Further, although it is desirable to configure the amplification optical fiber as a single mode fiber, there is a limit to the expansion of the MFD of the amplification optical fiber while maintaining the single mode condition.

Furthermore, in order to suppress noise light due to nonlinear optical effects and ASE, a plurality of shortened amplification optical fibers are prepared, and they are connected in series via a filter for removing spectral components other than signal light or pumping light. It is possible to arrange them, but the optical coupling loss when the signal light emitted from one amplification optical fiber enters the next amplification optical fiber becomes large, and it is not possible to amplify efficiently. It's hard to say. Further, the structure of the optical fiber amplifier becomes complicated.

Further, in the conventional optical fiber amplifier for generating high peak power, it is necessary to prevent the gain reduction due to the saturation of the amplification gain during the high average power operation of amplifying the optical pulse train having a short pulse interval. For this,
A powerful pumping light having a power about 10 times that of the signal light output after amplification is injected into the amplification optical fiber,
Keeping amplification optical fibers at high gain has been done.
However, there is a limit to the amount of single-mode excitation light that can be generated.

Further, in the conventional optical amplifier for the purpose of generating a high peak power, a multistage structure in which a plurality of amplification optical fibers are connected in series is usually used, and a pumping light source is provided for each of these amplification optical fibers. Was prepared, and pumping light having a power about 10 times the signal light output from each amplification optical fiber was supplied. For this reason, it is difficult to say that the structure of such an optical amplifier is simple, and it is difficult to say that optical amplification can be performed efficiently.

The present invention has been made under the above circumstances, and a first object of the present invention is to provide a light source device capable of generating efficiently amplified light of high brightness. .

A second object of the present invention is to provide a light irradiating device capable of irradiating an object with high brightness light.

[0015]

A first light source device of the present invention is a laser light generator (16) for generating light of a first wavelength.
0) and at least one optical fiber amplifier for amplifying the light generated by the laser light generator (1).
61), the first optical fiber amplifier (131) included in the optical amplification unit is added with an element excited by light having a second wavelength different from the first wavelength, and is incident. While amplifying the light of the first wavelength, the light of the first wavelength and the light of the second wavelength are substantially transmitted, and the noise light generated by the amplification of the light of the first wavelength is generated. Bragg grating (13) that reduces the amount of propagation
9) First optical fiber for amplification (135 ₁ )
A pumping light generator (133) for supplying the light of the second wavelength to the first amplifying optical fiber.

According to this, the light of the first wavelength generated by the laser light generator is amplified by the optical amplifier. The first optical fiber amplifier performs at least a part of the amplification action.
The amplification of the light of the first wavelength in the first optical fiber amplifier is formed by supplying the light of the second wavelength generated by the pump light generator as the pump light and exciting the added element. The induced radiation is generated when the light of the first wavelength passes through the first amplification optical fiber in which the population inversion of the energy level of the extra-shell electrons occurs.

By the way, the first amplification optical fiber includes
A Bragg diffraction grating (hereinafter, referred to as “loss”) that substantially transmits the light of the first wavelength and the light of the second wavelength and reduces the propagation amount of noise light generated by the amplification of the light of the first wavelength. (Also referred to as a "type fiber grating"), the loss type fiber grating transmits the light of the first wavelength and the light of the second wavelength. It does not affect the exciting action of the additional element by the light of the wavelength. On the other hand, due to amplification of the signal light and propagation of the amplified signal, spontaneous emission light (AS
E), stimulated Raman scattering (SRS), four-wave mixing (FW)
1) and 2) such as light due to a nonlinear optical effect such as M)
The noise light having a wavelength different from the wavelength is generated, but the amount of propagation of these noise light in the first amplification optical fiber is reduced by the lossy fiber grating. Therefore, the amount of directing the amplification energy supplied as the excitation light to the noise light is reduced.

Therefore, according to the first light source device of the present invention, in the first optical fiber amplifier, the amplification energy supplied as the pumping light can be efficiently utilized for the amplification of the signal light. With a simple structure, it is possible to generate efficiently amplified high-luminance light.

In the first light source device of the present invention, the optical amplifying section branches the first light of the second wavelength through the first amplifying optical fiber and emits the first optical branching device (137E _1). )
A second amplifying optical fiber (135 ₂ ) which is added with an element excited by the light of the second wavelength and amplifies the incident light of the first wavelength, and is emitted from the first optical branching device. And a second optical fiber amplifier including a pumping light supplier (137E ₂ ) for supplying the generated light of the second wavelength to the second amplification optical fiber.

The second light source device of the present invention comprises a laser light generator (160) for generating light of the first wavelength and a plurality of optical fiber amplifiers (131) for amplifying the light generated by the laser light generator. , 132), and a light source device including an element excited by light having a second wavelength different from the first wavelength,
A first amplification optical fiber (135 ₁ ) that amplifies the incident light of the first wavelength, and a pumping light generator that supplies the second wavelength light as pumping light to the first amplification optical fiber ( 133) and a first optical fiber amplifier (13
1) and; a first optical branching device (137) for branching and emitting the light of the second wavelength via the first amplification optical fiber.
E ₁ ); a second amplification optical fiber (135 ₂ ) to which an element excited by the light of the second wavelength is added, and which amplifies the incident light of the first wavelength, and the first optical branch A second optical fiber amplifier (132) including a pumping light supplier (137E ₁ ) for supplying the light of the second wavelength emitted from the container to the second amplification optical fiber. Is a light source device.

According to this, in the first optical fiber amplifier, the light of the second wavelength generated by the pumping light generator is
It is supplied to the first amplification optical fiber. As a result, the element added to the first amplification optical fiber is excited and the signal light having the first wavelength can be amplified.
Then, the light of the second wavelength that has not been used for pumping the element and has passed through the first amplification optical fiber is branched by the first optical branching device and supplied to the second optical fiber amplifier.

In the second optical fiber amplifier, the first
The light of the second wavelength supplied via the optical branching device is supplied to the second amplification optical fiber by the pumping light supply device.
As a result, the element added to the second amplification optical fiber is excited, and the signal light having the first wavelength can be amplified. That is, the second optical fiber amplifier can amplify the signal light without using a unique amplification energy generator.

Therefore, according to the second light source device of the present invention, it is possible to generate efficiently amplified high-luminance light with a simple structure.

In the first light source device and the second light source device of the present invention including the second optical fiber amplifier, the optical amplifying section causes the light of the second wavelength to be incident on the first amplifying optical fiber. A first fiber Bragg diffraction grating (136E ₁ ) provided near the end opposite to the end and reflecting the light of the second wavelength is further provided, and the first optical branching device is provided. Is reflected by the first fiber Bragg diffraction grating and branches the light of the second wavelength emitted from the incident end of the light of the second wavelength in the first amplification optical fiber. be able to.

Further, in the first light source device and the second light source device of the present invention including the second optical fiber amplifier, the second optical fiber amplifier is the first light source device in the second amplification optical fiber. A second fiber Bragg diffraction grating (136S ₂ ) provided near an end portion on the side opposite to the incident end side of the light of the wavelength and reflecting the light of the first wavelength; and the second fiber Bragg. A second beam splitter that splits the light of the first wavelength, which is reflected by the diffraction grating and is emitted from the incident end of the light of the first wavelength in the second amplification optical fiber.
The optical branching device (137S ₂ ) and may be further provided.

Further, in the first light source device and the second light source device of the present invention including the second optical fiber amplifier, the second optical fiber amplifier is configured such that the second wavelength in the second amplifying optical fiber is the second wavelength. A third fiber Bragg diffraction grating (136E ₂ ) is provided near the end portion on the side opposite to the light incident end side and reflects the light of the second wavelength.

In the first light source device and the second light source device of the present invention including the second optical fiber amplifier, the first wavelength is set to a wavelength of 1.55 μm band, and the second amplification light is used. The element added to the fiber may be erbium.

In the first and second light source devices of the present invention, the first optical fiber amplifier is provided on the side opposite to the incident end side of the light of the first wavelength in the first amplification optical fiber. And a fourth fiber Bragg diffraction grating (136S ₁ ) provided near the end of the mirror and reflecting the light of the first wavelength.
And; third light that is reflected by the fourth fiber Bragg diffraction grating and branches the light of the first wavelength emitted from the incident end of the light of the first wavelength in the first amplification optical fiber. It can be configured to further include a branching device (137S ₁ ).

Further, in the first and second light source devices of the present invention, the optical amplification section is provided with a plurality of optical fiber amplifiers connected in series with the first optical fiber amplifier as the final stage. can do.

Further, in the first and second light source devices of the present invention, the first wavelength is set to a wavelength in the 1.55 μm band, and the element added to the first amplification optical fiber is erbium. Can be

Further, in the first and second light source devices of the present invention, the wavelength conversion section (16) for converting the light of the first wavelength amplified by the optical amplification section into the light of the third wavelength.
It can be configured to further include 3).

Here, the first wavelength is a wavelength at which the light of the third wavelength is different from the absorption peak wavelength of the medium component of the optical path of the third wavelength, and according to the International Telecommunication Union. It can be one wavelength among a plurality of wavelengths that are standardly defined.

The light irradiating device of the present invention is a light irradiating device for irradiating an object with light, and includes the first or second light source device (16) of the present invention; and the light emitted from the light source device. A light irradiation device comprising: an irradiation optical system (12) for emitting the light toward the object.

According to this, since the light emitted from the first or second light source device of the present invention is applied to the object through the irradiation optical system, the efficiently generated light is applied to the object. be able to.

[0035]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows a schematic structure of an exposure apparatus 10 which is a light irradiation apparatus according to an embodiment, which is configured to include a light source device according to the present invention. This exposure apparatus 10 is
This is a step-and-scan type scanning exposure apparatus.

The exposure apparatus 10 includes an illumination system including a light source device 16 and an illumination optical system 12, and exposure illumination light (hereinafter referred to as "illumination light" or "exposure light") IL from the illumination system.
XY having a reticle stage RST holding a reticle R illuminated by a projection optical system PL for projecting the exposure light IL via the reticle R onto a wafer W as a substrate, and a Z tilt stage 58 holding the wafer W. The stage 14 and a control system for these are provided.

The light source device 16 has, for example, a wavelength of 19
It is a harmonic generation device that outputs an ultraviolet pulse light of 3.36 nm (substantially the same wavelength as the ArF excimer laser light).
The light source device 16 includes the illumination optical system 12, the reticle stage RST, the projection optical system PL, and the Z tilt stage 5.
8, an XY stage 14 and an exposure apparatus main body including a main body column and the like (not shown) on which each of these parts is mounted, together with an environmental chamber (hereinafter referred to as “chamber”) in which temperature, pressure, humidity, etc. are adjusted with high precision. ) 11 is stored. In the present embodiment, the light source device 1
Although all 6 are arranged in the chamber 11, only a part of the light source device 16, for example, a wavelength conversion unit 163 described later is provided in the chamber 11, especially on the same pedestal as the illumination optical system 12, and the wavelength conversion unit 163 is provided. 163 and the main body of the light source device 16 may be connected by an optical fiber or the like.

FIG. 2 is a block diagram showing the internal structure of the light source device 16 together with a main controller 50 for controlling the entire device. As shown in FIG. 2, the light source device 16 includes a light source unit 16A, a laser control device 16B, a light amount control device 16C, and the like.

The light source section 16A is a pulsed light generation section 16
0, an optical amplifier 161, a wavelength converter 163, and a beam monitor mechanism 164.

The pulsed light generator 160 includes a laser light source 160A, an optical coupler BS, an optical isolator 160B, and an electro-optic modulator (hereinafter referred to as "EOM") 160C.
And so on.

In the present embodiment, the laser light source 160A is a single wavelength oscillation laser, for example, International Telecommunication Union (IT).
U) is a wavelength of 1546.92 nm (hereinafter, referred to as “ITU-Grid standard wavelength”), which is one of the wavelengths (hereinafter referred to as “ITU-Grid standard wavelength”) that are standardized at intervals of approximately 0.8 nm for a wavelength in the range of 1530 nm to 1600 nm. A continuous wave output (hereinafter referred to as “CW output”) DFB semiconductor laser is used with an oscillation wavelength of “wavelength λ _S ”). In the following description, the laser light source 160A will also be appropriately referred to as "DFB semiconductor laser 160A".

Oscillation wavelength 1 of DFB semiconductor laser 160A
546.92 nm is the 8th harmonic (wavelength: 193.
(36 nm) is close to the oscillation wavelength of the ArF excimer laser and is a wavelength that can avoid the peak of the absorption spectrum of oxygen molecules as shown by the solid line in FIG. 3 as much as possible. Has been done. Note that in FIG. 3, the ITU-Grid standard wavelength is indicated by {circle around (1)}, and the wavelength of 1546.92 nm adopted in the present embodiment is indicated by {circle around ()}.

The DFB semiconductor laser 160A is usually provided on a heat sink, and these are housed in a housing. In this embodiment, the DFB semiconductor laser 1
A temperature adjuster (for example, a Peltier element) is provided on a heat sink attached to 60A, and the oscillation wavelength can be controlled (adjusted) by controlling the temperature by the laser control device 16B.

The optical coupler BS has a transmittance of 9
About 7% is used. Therefore, the laser light from the DFB semiconductor laser 160A is transmitted by the optical coupler BS.
The light is branched into two, about 97% of which is directed toward the optical isolator 160B in the next stage, and the remaining about 3% is incident on the beam monitor mechanism 164.

The beam monitor mechanism 164 includes an energy monitor (not shown) composed of a photoelectric conversion element such as a photodiode. The output of this energy monitor is
It is supplied to the main controller 50 via the laser controller 16B. The main controller 50 detects the energy power of the laser light based on the output of the energy monitor, and the DFB semiconductor laser 160A detects the energy power of the laser light via the laser controller 16B. The light amount of the oscillated laser light is controlled as necessary.

The optical isolator 160B allows only light in the direction from the optical coupler BS to the EOM 160C to pass therethrough, and blocks light in the opposite direction from passing therethrough. With this optical isolator 160B, the DF caused by the reflected light (return light)
The change of the oscillation mode of the B semiconductor laser 160A and the generation of noise are prevented.

The EOM 160C is an optical isolator 1.
This is for converting laser light (CW light (continuous light)) that has passed through 60B into pulsed light. As the EOM 160C, an electro-optic modulator (for example, a two-electrode modulator) having an electrode structure that is chirp-corrected so that the wavelength spread of the semiconductor laser output with the change of the refractive index with time is reduced is used. EOM160C is a light quantity control device 16
The pulsed light modulated in synchronization with the voltage pulse applied from C is output. For example, DFB with EOM160C
Laser light oscillated by the semiconductor laser 160A has a pulse width of 1 ns and a repetition frequency of 100 kHz (pulse cycle of about 1
0 μs) pulse light is modulated. The repetition frequency is the spontaneous emission (ASE: Am) in the optical fiber amplifier.
A value that can suppress the effect of noise caused by plified Spontaneous Emission) is selected.

The voltage applied to the EOM 160C and the DF
It is desirable that the output light be pulsed in combination with the control of the supply current to the B semiconductor laser 160A. In such a case, the extinction ratio can be improved. By doing so, it becomes possible to easily generate pulsed light having a narrow pulse width while improving the extinction ratio as compared with the case where only the EOM160C is used, and the oscillation interval of the pulsed light and the start of oscillation It is possible to control the stop and the like more easily. An acousto-optic modulator (AOM) can be used instead of the EOM 160C.

The optical amplification section 161 amplifies the pulsed light from the EOM 160C, and as shown in FIG. 4, periodically distributes the pulsed light from the EOM 160C in time sequence and branches (for example, 128 branches). Optical splitter 1
66 and a plurality of optical fiber amplifiers 167.

As shown in FIG. 5, the optical fiber amplifier 167 includes a first optical fiber amplifier 131, an optical circulator 137E ₁ as a first optical branching device,
A second optical fiber amplifier 132, an optical coupler 134,
And a photoelectric conversion element 138. This optical fiber amplifying device 167 includes a first optical fiber amplifier 131 and a second optical fiber amplifier 131.
The first optical fiber amplifier 131 is a post-stage amplifier, and the second optical fiber amplifier 132 is a pre-stage amplifier.

Here, the optical circulator 137E ₁ is
The light incident on the terminal a is emitted from the terminal b, and the light incident on the terminal b is emitted from the terminal c. An optical circulator that performs such a function is well known as an optical component, and thus detailed description thereof will be omitted. Further, the optical coupler 134 is configured similarly to the above-mentioned optical coupler BS.

The first optical fiber amplifier 131 is
(A) The amplification optical fiber 135 ₁ as the first amplification optical fiber, and (b) the amplification optical fiber 135 ₁ provided near the incident end of the amplification target light and having a wavelength λ _E ( A fiber grating element 136E ₁ serving as a first fiber Bragg diffraction grating that reflects almost 100% of light having a wavelength of 1.48 μm, and (c) amplification target light in the amplification optical fiber 135 _1, that is, light having a wavelength λ _S. A fiber grating element 136S ₁ serving as a second fiber Bragg diffraction grating provided near the end opposite to the incident end and reflecting almost 100% of light of wavelength λ _S
(D) a pumping light source 133 as a pumping light generator for generating pumping light; and (e) a second optical fiber amplifier 132.
The optical fiber 135 ₁ for amplifying the light of wavelength λ _S emitted from the
And an optical circulator 137S ₁ as a second optical branching device for branching the light of wavelength λ _S amplified by the amplification optical fiber 135 ₁ .

Here, the amplification optical fiber 135 ₁ has erbium (Er) added to its core, and
A loss type fiber grating 139 having a transmission characteristic as shown in FIG. 5 is formed. The loss-type fiber grating 139 is realized by a long period grating or a side tap grating which is a kind of fiber Bragg diffraction grating. Such long-period gratings and side-tap gratings have a property of emitting light having a wavelength that propagates through the core determined by the grating spacing in the diffraction grating to the cladding side. Since lossy fiber gratings such as long-period gratings and side-tap gratings are well known, detailed description thereof will be omitted. The amplification optical fiber 1
Since 35 ₁ amplifies pulsed light having a significantly higher peak power than signal light in optical fiber communication, the so-called short amplification light is shorter than the amplification optical fiber in optical fiber communication. Fiber is used.

As the excitation light source 133, a cascade Raman laser using an ytterbium (Yb) -doped optical fiber as a laser medium, which emits light having a wavelength of 1.48 μm as excitation light, is used in this embodiment. There is.
The excitation light emitted from the excitation light source 133 is transmitted through the optical circulator 137E ₁ to the amplification optical fiber 13
It is incident on 5 ₁ . As described above, the amplification optical fiber fiber 135 ₁ is the amplifying optical fiber of the short, and the need to ensure a high-gain amplifier is used in amplification in the first amplifying optical fiber 135 ₁ Excitation light having a large power, for example, about 10 times the power is generated. Also,
The emitted light amount of the excitation light source 133 is controlled by the light amount control device 16C.

[0056] Also, the optical circulator 137S ₁ is configured similarly to the optical circulator 137E ₁ described above.

The second optical fiber amplifier 132 is
The amplification optical fiber 135 ₂ of the second amplifying optical fiber (a), (b) provided near the end of the entrance side of the amplified light in the amplification optical fiber 135 _2, the excitation light having a wavelength of lambda _E Fiber grating element 13 as a third fiber Bragg diffraction grating that reflects almost 100% of light
And 6E _2, (c) the incident end of the light to be amplified light i.e. wavelength lambda _S in the amplification optical fiber 135 ₂ provided in the vicinity of the opposite end, and reflects almost 100% of light of wavelength lambda _S The fiber grating element 136S ₂ serving as the fourth fiber Bragg diffraction grating, and (d) the light of the wavelength λ _E supplied from the first optical fiber amplifier 131 through the optical circulator 137E ₁ are used to amplify the optical fiber 13 for amplification.
( ₂ ) an optical circulator 137E ₂ as a pumping light supplier for preventing the light having the wavelength λ _E via the amplification optical fiber 135 ₂ from returning to the first optical fiber amplifier 131 while being incident on the optical fiber 5 ₂ ; The light of wavelength λ _S emitted from the optical branching device 166 is incident on the amplification optical fiber 135 _1, and the light of wavelength λ _S amplified by the amplification optical fiber 135 ₂ is branched to generate the first optical fiber. Amplifier 131
And an optical circulator 137S ₂ as a third optical branching device that emits toward the optical path.

Here, the amplification optical fiber 135 ₂ has erbium (Er) added to its core, like the amplification optical fiber 135 ₁ described above. The amplification optical fiber 135 ₂ also employs a shortened amplification optical fiber similarly to the amplification optical fiber 135 ₁ described above.

[0059] Also, the optical circulator 137E ₂ and the optical circulator 137S ₂ is configured similarly to the optical circulator 137E ₁ or the optical circulator 137S ₁ described above.

The optical fiber amplifier 167 described above is used.
The respective components are optically connected by a single mode optical fiber as appropriate.

The optical fiber amplifier 167 configured as described above operates as follows, amplifies the light of the wavelength λ _S emitted from the optical branching device 166, and the wavelength converter 16
Eject toward 3.

In this optical amplification, first, the optical fiber amplifier 167 is set in a state capable of optical amplification. In this setting, the pumping light source 133 of the first optical fiber amplifier 131, which is a supply source of amplification energy, emits light of wavelength λ _E. The light of wavelength λ _E emitted from the excitation light source 133 is input to the terminal a of the optical circulator 137E ₁ and emitted from the terminal b, and then the fiber grating element 1
The light passes through 36S ₁ and enters the amplification optical fiber 135 ₁ . Light of the wavelength lambda _E incident on the amplifying optical fiber 135 _1, after traveling the amplification optical fiber 135 ₁ medium, leading to a fiber grating element 136E _1.

When reaching the fiber grating element 136E ₁ , the light of wavelength λ _E is reflected and travels in the direction opposite to the traveling direction up to then. That is, the light having the wavelength λ _E reciprocates in the amplification optical fiber 135 ₁ . Due to this round trip, the density of the light of the wavelength λ _{E in} the amplification optical fiber 135 ₂ , that is, the excitation light, is almost twice that in the case of unidirectional excitation, that is, the same as in the case of bidirectional excitation. As a result, with respect to the supplied pumping light energy, the amplification optical fiber 135 ₁
The extra-shell electrons of Er added to E are efficiently excited, and E
The population inversion occurs in the energy level distribution of the extra-shell electrons of r.

[0064] Subsequently, light of wavelength lambda _E is transmitted through the fiber grating element 136S _1, input to the terminal b of the optical circulator 137E _1. Then, the light of the wavelength λ _E is emitted from the terminal c of the optical circulator 137E ₁ toward the second optical fiber amplifier 132. Thus
Light of the wavelength lambda _E emitted from the terminal c of the circulator 137E _1, the wavelength lambda _E of the excitation light source 133 mentioned above is emitted
In view of the power of the light and the amount of use of the light of wavelength λ _E in the amplification optical fiber 135 ₁ , sufficient energy is available as the power of the pumping light to be supplied to the amplification optical fiber 135 ₂ used for the pre-stage amplification. is doing.

The light of wavelength λ _E emitted from the terminal c of the optical circulator 137E ₁ is emitted by the optical circulator 137E ₂
After being input to the terminal a of the above and emitted from the terminal b, the light passes through the fiber grating element 136S ₂ and enters the amplification optical fiber 135 ₂ . Light of the wavelength lambda _E incident on the amplifying optical fiber 135 _2, after traveling through the amplification optical fiber 135 ₂ medium, leading to a fiber grating element 136E _2.

When reaching the fiber grating element 136E ₂ , the light of wavelength λ _E is reflected and travels in the direction opposite to the traveling direction up to that point. That is, the light of the wavelength λ _E reciprocates in the amplification optical fiber 135 ₂ . Such wavelength λ _E
Due to the round trip of the light, the extra-shell electrons of Er added to the amplification optical fiber 135 ₂ are efficiently excited, and the energy level distribution of the extra-shell electrons of Er is distributed, as in the case of the amplification optical fiber 135 _1. A population inversion at is generated.

[0067] Subsequently, light of wavelength lambda _E is transmitted through the fiber grating element 136S _2, is input to the terminal b of the optical circulator 137E _2. Then, the light of the wavelength λ _E is emitted from the terminal c of the optical circulator 137E ₂ .

As described above, the amplification optical fiber 1 is excited by the excitation light of the wavelength λ _E emitted from the excitation light source 133.
When Er added to 35 ₁ and 135 ₂ is excited, the optical fiber amplifier 167 can amplify the light of the wavelength λ _S emitted from the optical branching device 166.

In such an amplifiable state, the optical splitter
Wavelength λ emitted from 166_SOf the optical fiber amplifier
Input to the table 167. In the optical fiber amplifier 167
The wavelength λ emitted from the optical splitter 166._SLight is light
Circulator 137S₂Is incident on terminal a of terminal b?
After being emitted from the fiber grating element 136E
₂Amplification optical fiber 135₂Incident on. amplification
Optical fiber 135₂Wavelength λ incident on_SLight for amplification
Optical fiber 135₂After proceeding through the inside,
Swing element 136S₂Leading to.

Fiber grating element 136S₂To
Reach the wavelength λ_SLight is reflected and the direction of travel up to that point
And goes in the opposite direction. That is, the wavelength λ_SThe light increases
Width optical fiber 135₂Travel back and forth. Such wavelength λ_S
Amplification optical fiber 135 during the round trip of the light₂At
Pass wavelength λ_SThe stimulated emission caused by the
λ _SLight is amplified. Here, the wavelength λ that is the amplified light_S
Optical fiber 135 whose light is an amplification medium₂Going in
The wavelength λ with high amplification factor_SLight is amplified
It In addition, the second optical fiber amplifier 1 which is the pre-stage amplifier
At 32, the peak power doesn't increase so much
And the optical fiber 135 for amplification₂Non-linear optical effect in
The amount of noise light generated by the fruit is small.

Subsequently, the light of wavelength λ _S is transmitted through the fiber grating element 136E ₂ and input to the terminal b of the optical circulator 137S ₂ . Then, the light having the wavelength λ _S amplified in the amplification optical fiber 135 ₂ is emitted from the terminal c of the optical circulator 137S ₂ toward the first optical fiber amplifier 131.

The light of wavelength λ _S emitted from the terminal c of the optical circulator 137S ₂ is emitted by the optical circulator 137S ₁
After being input to the terminal a of the above and emitted from the terminal b, the light passes through the fiber grating element 136E ₁ and enters the amplification optical fiber 135 ₁ . Light of the wavelength lambda _S incident on the amplifying optical fiber 135 _1, after traveling the amplification optical fiber 135 ₁ medium, leading to a fiber grating element 136S _1.

When reaching the fiber grating element 136S ₁ , the light of the wavelength λ _S is reflected and travels in the direction opposite to the traveling direction up to that point. That is, the light of the wavelength λ _S reciprocates in the amplification optical fiber 135 ₁ . During such a round trip, the light of the wavelength λ _S is amplified with a high amplification factor as in the case of the amplification optical fiber 135 ₂ .

In the high gain amplification in the amplifying optical fiber 135 ₁ , light of wavelength λ _S having high peak power is generated. As a result, in the amplification optical fiber 135 ₁ , stimulated Raman scattering (SRS) or four wave mixing (FW) is performed.
Due to the non-linear optical phenomenon of M), noise light having a wavelength different from the wavelength λ _S is generated. The wavelength range of the main noise light generated by such SRS and FWM is shown in FIG. Further, the main wavelength range of noise light due to spontaneous emission light (ASE) spans the wavelength range in which Er (or the amplification medium) has a gain.

However, in the amplification optical fiber 135 ₁ ,
As described above, the lossy fiber grating 39 having the transmission characteristics shown in FIG. 6 is formed, and the propagation amount of noise light in the amplification optical fiber 135 ₁ is reduced. Thus, since the amplification of noise light due to the noise light is propagated through the amplification optical fiber 135 ₁ is limited, the amplification power of the amplification optical fiber 135 ₁ is directed to the amplification of the noise light is suppressed. Therefore, the amplification power of the amplification optical fiber 135 ₁ is efficiently used to amplify the signal light, that is, the light of the wavelength λ _S , and the light of the wavelength λ _S is efficiently amplified.

[0076] Returning to FIG. 5, the light of the amplified wavelength lambda _S in the amplification optical fiber 135 ₁ is transmitted through the fiber grating element 136E _1, an optical circulator 13
Input to terminal b of 7S ₁ . And the amplified wavelength λ _S
Light is emitted from the terminal c of the optical circulator 137S ₁ .

The light having the wavelength λ _S emitted from the terminal c of the optical circulator 137S ₁ is reflected by the optical coupler 134.
Of the wavelength conversion unit 16 in the next stage
3 and the remaining 3% is the photoelectric conversion element 138.
The light amount detection result by the photoelectric conversion element 138 is supplied to the light amount control device 16C. Then, in the light quantity control device 16C, each optical fiber amplification device 1
Each pumping light source 133 is feedback-controlled so that the light output from 67 becomes constant (that is, balanced).

The wavelength conversion unit 163 has a plurality of nonlinear light beams.
Pulsed light from the optical amplifier 161 (wavelength 1
546.92 nm (= λ_S) Light) to its 8th harmonic
Wavelength converted and output wave almost the same as ArF excimer laser
Length (193.36 nm (= λ _S/ 8)) pulsed ultraviolet light
To occur.

FIG. 7 shows an example of the structure of the wavelength conversion section 163. Here, a specific example of the wavelength conversion unit 163 will be described based on this drawing. In FIG. 7, the light having the wavelength λ _S emitted from the optical amplification section 161 is used as a fundamental wave to be converted into an 8th harmonic (harmonic wave) by using a non-linear optical crystal, which is almost the same as the ArF excimer laser. A configuration example for generating ultraviolet light having a wavelength λ _S , which is a wavelength, is shown.

In the wavelength converter 163 of FIG. 7, the fundamental wave (wavelength λ _S ) → double wave (wavelength (λ _S / 2)) → third wave (wavelength (λ _S / 3)) → fourth wave ( Wavelength conversion is performed in the order of wavelength (λ _S / 4)) → 7th harmonic (wavelength (λ _S / 7)) → 8th harmonic (wavelength (λ _S / 8)).

More specifically, the light (fundamental wave) having a wavelength of 1546.92 nm (frequency ω) emitted from the optical amplification section 161 enters the first-stage nonlinear optical crystal 183. When the fundamental wave passes through this nonlinear optical crystal 183, 2
Double the frequency ω of the fundamental wave due to the generation of the second harmonic, that is, frequency 2ω (wavelength: 773.46 nm (= λ _S / 2))
Second harmonic wave is generated.

As the first-stage nonlinear optical crystal 183, a LiB ₃ O ₅ (LBO) crystal is used, and the fundamental wave is 2
For the phase matching to convert the wavelength to a harmonic, a method by adjusting the temperature of the LBO crystal, NCPM (Non-Critical Phase Match)
ing) is used. Since NCPM does not cause an angle deviation (Walk-off) between the fundamental wave and the second harmonic wave in the nonlinear optical crystal, it enables highly efficient conversion into the second harmonic wave, and the generated second harmonic wave is the Walk. This is advantageous because the beam is not deformed by -off.

The fundamental wave transmitted without wavelength conversion by the nonlinear optical crystal 183 and the second harmonic wave generated by wavelength conversion are respectively delayed by a half wavelength and a wavelength by the wave plate 184 at the next stage. As a result, only the fundamental wave has its polarization direction rotated by 90 degrees. After this, the fundamental wave and the second harmonic wave are collected by the condenser lens 1.
The light enters the second-stage nonlinear optical crystal 186 via 85. An LBO crystal is used as the second-stage nonlinear optical crystal 186. This LBO crystal 186 is an NCPM whose temperature is different from that of the first stage nonlinear optical crystal (LBO crystal) 183.
Used in. In the non-linear optical crystal 186, the second harmonic generated in the first-stage non-linear optical crystal 183 and the fundamental wave that has passed through the non-linear optical crystal 183 without wavelength conversion generate a third harmonic (wavelength: 515). 0.62 nm (=
λ _S / 3)) is obtained.

Next, the 3 obtained by the nonlinear optical crystal 186 was used.
The dichroic mirror 187 separates the harmonic wave from the fundamental wave and the second harmonic wave that have passed through the nonlinear optical crystal 186 without wavelength conversion. The third harmonic wave reflected here is collected by the condenser lens 190 and the dichroic mirror 19.
The light passes through 3 and enters the fourth-stage nonlinear optical crystal 195.
On the other hand, the fundamental wave and the second harmonic wave transmitted through the dichroic mirror 187 pass through the condenser lens 188 and enter the third stage nonlinear optical crystal 189.

As the third stage non-linear optical crystal 189, L
The BO crystal is used, and the L
While passing through the BO crystal, the second harmonic wave is 2 in the LBO crystal.
4th harmonic (wavelength: 386.73nm)
(= Λ _S / 4)). Nonlinear optical crystal 189
The 4th harmonic and the fundamental wave transmitted therethrough are separated by the dichroic mirror 191, and the fundamental wave transmitted there passes through the condenser lens 194 and is reflected by the dichroic mirror 196 to form 5 stages. It is incident on the nonlinear optical crystal 198 of the eye. On the other hand, the fourth harmonic wave reflected by the dichroic mirror 191 reaches the dichroic mirror 193 through the condensing lens 192, where it is coaxially combined with the third harmonic wave reflected by the dichroic mirror 187 to form four stages. It is incident on the nonlinear optical crystal 195 of the eye.

As the fourth stage non-linear optical crystal 195,
β-BaB ₂ O ₄ (BBO) crystal is used,
7th harmonic (wavelength: 220.9
9 nm (= λ _S / 7)) is obtained. Nonlinear optical crystal 195
The 7th harmonic wave obtained in step 2 passes through the condenser lens 197,
The dichroic mirror 196 combines the fundamental wave that has passed through the dichroic mirror 191 coaxially with the fundamental wave and makes it enter the fifth-stage nonlinear optical crystal 198.

LB as the fifth stage non-linear optical crystal 198
An O crystal is used, and an 8th harmonic (wavelength: 193.36 nm (= λ _S / 8)) is generated by sum frequency generation from the fundamental wave and the 7th harmonic.
To get BBO crystal for 7th harmonic generation 1
Instead of the 95 and 8th harmonic LBO crystal 198,
CsLiB ₆ O ₁₀ (CLBO) crystal, Li ₂ B ₄ O ₇ (L
It is also possible to use B4) or CsB ₃ O ₅ (CBO) crystals.

Returning to FIG. 1, the illumination optical system 12 is configured to include an optical integrator, a variable ND filter, a reticle blind and the like (all not shown). Here, as the optical integrator, a fly-eye lens, an internal reflection type integrator (rod integrator or the like), a diffractive optical element or the like is used. The configuration of such an illumination optical system is disclosed in, for example, Japanese Patent Laid-Open No.
It is disclosed in Japanese Patent Publication No. 0-112433. The exposure light IL emitted from the illumination optical system 12 has its optical path bent vertically downward by a mirror M, and then passes through a condenser lens 32 and a rectangular illumination region 42R on the reticle R held on the reticle stage RST. Illuminate with a uniform illuminance distribution.

The reticle R is placed on the reticle stage RST, and is suction-held via a vacuum chuck or the like (not shown). The reticle stage RST is movable in a horizontal plane (XY plane) and is scanned by the reticle stage drive unit 49 in a predetermined stroke range in the scanning direction (here, the Y direction which is the left-right direction on the paper surface of FIG. 1). It has become. The position and rotation amount of the reticle stage RST during this scanning are determined by the reticle stage RS.
This laser interferometer 54R is measured by an external laser interferometer 54R via a movable mirror 52R fixed on T.
The measured value of is supplied to the main controller 50.

The projection optical system PL is, for example, a both-side telecentric reduction system, and has a common optical axis AX in the Z-axis direction.
It is composed of a plurality of lens elements having. The projection optical system PL has a projection magnification β of, for example, ¼, ⅕, ⅙, or the like. Therefore, when the illumination area 42R on the reticle R is illuminated by the exposure light IL as described above, the illumination area 42R in the pattern formed on the reticle R is illuminated.
An image obtained by reducing a part of the image with a projection magnification β by the projection optical system PL is formed in a rectangular projection area 42W that is conjugate with the illumination area 42R in the field of view of the projection optical system PL, and the resist applied on the surface of the wafer W. The reduced image is transferred on top.

The XY stage 14 is two-dimensionally driven by the wafer stage drive unit 56 in the Y direction which is the scanning direction and in the X direction (the direction orthogonal to the paper surface in FIG. 1) orthogonal to the Y direction. A wafer W is held on a Z tilt stage 58 mounted on the XY stage 14 by vacuum suction or the like via a wafer holder (not shown). The Z tilt stage 58 adjusts the position (focus position) in the Z direction of the wafer W by, for example, three actuators (piezo elements or voice coil motors), and at the same time, the wafer W with respect to the XY plane (the image plane of the projection optical system PL). It has the function of adjusting the inclination angle of. Also, XY
The position of the stage 14 is adjusted by the external laser interferometer 54W via the movable mirror 52W fixed on the Z tilt stage 58.
The measurement value of the laser interferometer 54W is supplied to the main controller 50.

Here, the movable mirror actually includes an X movable mirror having a reflection surface perpendicular to the X axis and a Y movable mirror having a reflection surface perpendicular to the Y axis. Interferometers for X-axis position measurement, Y-axis position measurement, and rotation (including yawing amount, pitching amount, rolling amount) measurement are also provided, but in FIG. 1, these are representative. , A moving mirror 52W and a laser interferometer 54W.

On the Z tilt stage 58, a fiducial mark plate FM used when performing reticle alignment or the like described later is provided. The surface of the fiducial mark plate FM has substantially the same height as the surface of the wafer W. Reference marks such as a reticle alignment reference mark and a baseline measurement reference mark are formed on the surface of the reference mark plate FM.

Further, in the exposure apparatus 10 of the present embodiment, as shown in FIG. 1, under the control of the main controller, a large number of measurements are set on the image plane (XY plane) of the projection optical system PL. Irradiation optical system 60a for irradiating the image forming light beams for forming the images of the pinholes or slits toward the points from the oblique direction with respect to the optical axis AX, and the reflection of these image forming light beams on the surface of the wafer W. An oblique incident light type multipoint focus position detection system (focus sensor) including a light receiving optical system 60b that receives a light beam is provided. The detailed configuration of a multi-point focal position detection system (focus sensor) similar to that of this embodiment is as follows.
For example, it is disclosed in JP-A-6-283403.

At the time of scanning exposure or the like, main controller 50 determines the Z position of the surface of a part of the shot area where the measurement point is present, based on the Z position detected for each measurement point from light receiving optical system 60b. While sequentially calculating the tilt amount, and controlling the Z position of the Z tilt stage 58 via a drive system (not shown) based on the calculation result, auto focus (automatic focusing) and auto leveling are executed.

The main controller 50 includes a CPU (central processing unit), ROM (read only memory), RA
It is configured to include a so-called microcomputer (or workstation) including M (random access memory) and the like, and performs various controls described so far, and for example, a reticle R so that the exposure operation can be performed accurately. And synchronous scanning of the wafer W, stepping of the wafer W, exposure timing, etc. are controlled. Further, in the present embodiment, the main control device 50 controls the exposure amount at the time of scanning exposure as will be described later, and controls the entire device as a whole.

Specifically, main controller 50 causes reticle R to move in the + Y direction (or −Y direction) with respect to illumination region 42R at speed V _R = V via reticle stage RST during scanning exposure, for example. In synchronism with scanning, the wafer W is moved through the XY stage 14 in the −Y direction (or + Y direction) with respect to the projection area 42W at a velocity V _W = β · V (β is a projection from the reticle R onto the wafer W. So that scanning is performed at a magnification), the positions and speeds of the reticle stage RST and the XY stage 14 are respectively controlled via the reticle stage drive unit 49 and the wafer stage drive unit 56 based on the measurement values of the laser interferometers 54R and 54W. To do. Also,
At the time of stepping, main controller 50 uses wafer interferometer 54W to measure wafer stage drive unit 56 based on the measured value.
The position of the XY stage 14 is controlled via.

Next, in the exposure apparatus 10 of the present embodiment, an exposure sequence for exposing a predetermined number (N) of wafers W with reticle patterns will be described. Main controller 50
The control operation will be mainly described.

First, main controller 50 loads reticle R to be exposed onto reticle stage RST using a reticle loader (not shown).

Next, reticle alignment is performed using a reticle alignment system (not shown), and baseline measurement of an off-axis type alignment system (not shown) is performed using the reference marks described above.

Next, main controller 50 instructs a wafer transfer system (not shown) to replace wafer W. As a result, the wafer transfer system and the wafer transfer mechanism (not shown) on the XY stage 14 perform wafer exchange (simple wafer loading when there is no wafer on the stage). Then, a series of alignment process steps such as fine alignment (EGA, etc.) are performed using the alignment system on which the baseline measurement is performed. Since these wafer exchanges and wafer alignments are performed in the same manner as in a known exposure apparatus, further detailed description will be omitted here.

Next, based on the above alignment result and shot map data, the operation of moving the wafer W to the scanning start position for exposure of each shot area on the wafer W and the above-mentioned scanning exposure operation are repeated. Then, the reticle pattern is transferred to the plurality of shot areas on the wafer W by the step-and-scan method. During the scanning exposure, the main controller 50 gives a command to the light quantity controller 16C to control the exposure light quantity in order to give the target integrated exposure quantity determined according to the exposure condition and the resist sensitivity to the wafer W.

When the exposure of the first wafer W is completed, main controller 50 instructs a wafer transfer system (not shown) to replace the wafer W. As a result, the wafer transfer system and the wafer transfer mechanism (not shown) on the XY stage 14 perform wafer exchange, and thereafter, search alignment and fine alignment are performed on the exchanged wafer in the same manner as described above.

Then, in the same manner as described above, this wafer W
The reticle pattern is transferred to the plurality of shot areas above by a step-and-scan method.

When the illuminance changes due to changes in the exposure conditions and / or the reticle pattern, the light source device 1 is provided so that a proper exposure amount is given to the wafer (resist).
It is desirable to control at least one of the frequency and the peak power of the light emitted from No. 6. At this time, the scanning speed of the reticle and the wafer may be adjusted in addition to at least one of the frequency and the peak power.

As described above, according to the light source device 16 of this embodiment, the amplification target optical fiber 135 ₁ which is the amplification medium of the first optical fiber amplifier 131 included in the optical amplification section 161 is provided with the amplification target light. Wavelength λ _S and pumping light wavelength λ
_Since the loss-type fiber grating 39 that transmits the _E light and reduces the propagation of the noise light generated by the optical amplification in the amplification optical fiber 135 ₁ is formed, the amplification power supplied as the excitation light is used. The consumption amount of the noise light is reduced, and the amplification power supplied as the excitation light can be efficiently used for the amplification of the signal light.

[0107] Also, among the excitation light excitation light source 133 is generated, which was not used in the amplification optical fiber 135 ₁ is branched by the optical circulator 137E _1, is the amplification medium of the second optical fiber amplifier 132 Since it is supplied to the amplification optical fiber 135 ₂ as pumping light, the power of the pumping light generated by the pumping light source 133 can be efficiently used as the amplification power and the number of pumping light sources is reduced. Can be

Further, a fiber grating 136E for reflecting the light having the wavelength λ _E of the pumping light is provided near each of the ends of the amplifying optical fiber 135 ₁ and the amplifying optical fiber 135 ₂ on the side opposite to the incident end side of the pumping light. ₁ , 136E ₂ are provided, and the pumping light reciprocates the amplifying optical fiber 135 ₁ and the amplifying optical fiber 135 _2, respectively, so that the pumping light density can be increased. The respective optical amplification factors can be improved.

Further, a fiber grating for reflecting the light having the wavelength λ _S of the amplification target light is provided near each of the ends of the amplification optical fiber 135 ₁ and the amplification optical fiber 135 ₂ opposite to the incident end side of the amplification target light. 136S ₁ , 13
Since 6S ₂ is provided and the amplification target light reciprocates through the amplification optical fiber 135 ₁ and the amplification optical fiber 135 _2, respectively, the optical path length for performing the amplification operation can be lengthened.
Also, the optical amplification factors of the second optical fiber amplifiers 131 and 132 can be improved. Further, since the fiber grating that reflects the light of the wavelength λ _S is used, only the light of the wavelength λ _S is reflected and the noise components such as ASE, FWM, and SRS are transmitted, and as a result, the noise component from the amplification path is transmitted. Can be removed.

Further, since the first optical fiber amplifier 131 is the post-stage amplifier and the second optical fiber amplifier 132 is the pre-stage amplifier, it is likely to occur in the amplification optical fiber 135 ₁ of the post-stage amplifier having a high peak power. Optical fiber for amplification of noise light by nonlinear optical effect and ASE 1
Since the amount of propagation in 35 ₁ is reduced by the lossy fiber grating, it is possible to efficiently perform optical amplification.

Further, since the light of the wavelength λ _S efficiently amplified in the optical amplifier 161 is wavelength-converted in the wavelength converter 163, the wavelength-converted light can be obtained efficiently.

In addition, the wavelength λ _{S of the} fundamental wave is a wavelength at which the wavelength of the eighth harmonic (λ _S / 8) used as exposure light is different from the absorption peak wavelength of oxygen, and according to the International Telecommunication Union. 1 out of multiple standardized wavelengths
Since two wavelengths are selected, the DFB semiconductor laser 160A is a standard optical component mass-produced for generating ultraviolet light having the same wavelength as the ArF excimer laser that efficiently reaches the wafer W to be exposed. , The fiber grating elements 137S ₁ and 137S ₂ .

Further, according to the exposure apparatus of the present embodiment, the reticle R can be irradiated with the high-intensity illumination light IL in scanning exposure, so that the pattern formed on the reticle R is transferred onto the wafer W accurately and efficiently. be able to.

In the above embodiment, the loss-type fiber grating 139 is not formed in the amplification optical fiber 135 ₂ in the second optical fiber amplifier 132, but like the amplification optical fiber 135 ₁ , there is no loss. It is also possible to form the mold fiber grating 139.

Further, in the above embodiment, the loss type fiber grating 139 is formed in the amplification optical fiber 135 ₁ in the first optical fiber amplifier 131.
Depending on the peak power of the generated pulsed light, efficient optical amplification can be performed without forming the lossy fiber grating 139, like the amplification optical fiber 135 ₂ .

Further, in the above embodiment, the optical fiber amplifier 167 includes the first optical fiber amplifier 131 and the second optical fiber amplifier 131.
The two-stage configuration with the optical fiber amplifier 132 of
One or more optical fiber amplifiers having a configuration similar to that of the second optical fiber amplifier 132 may be provided in front of the second optical fiber amplifier 132. In such a case, the light having the wavelength λ _E emitted from the C terminal of the optical circulator 137E ₂ of the second optical fiber amplifier 132 is supplied to the optical fiber amplifier in the stage preceding the second optical fiber amplifier 132 as pumping light. can do. This makes it possible to increase the number of amplification stages while suppressing an increase in the number of pumping light sources.

Further, in the above embodiment, the excitation light source 1
Although a cascade Raman laser having an ytterbium (Yb) -doped optical fiber as a laser medium is used as 33, another laser light source such as a semiconductor laser light source can be used if the oscillation wavelength is a desired wavelength.

Further, in the above embodiment, the fiber grating elements 136E ₁ and 136S ₁ are separate parts from the amplifying optical fiber 135 _1, and the fiber grating elements 136E ₂ and 136S ₂ are different from the amplifying optical fiber 135 ₂ . Although it is a separate component, amplification optical fiber 1
35 ₁ to the fiber grating elements 136E ₁ and 136
A fiber grating that performs the same function as at least _one of S ₁ may be formed, and the amplification optical fiber 135 ₂ may be provided with a fiber grating element 136E ₂ ,
A fiber grating that performs the same function as at least one of 136S ₂ may be formed.

Further, in the above-described embodiment, in the first optical fiber amplifier 131, by using the fiber grating element 136E ₁ , a light density similar to so-called bidirectional pumping is realized in the amplification optical fiber 135 ₁ . However, as shown in FIG. 8 or FIG. 9, the first optical fiber amplifier 131 may be configured as an optical fiber amplifier that actually bidirectionally pumps. Note that, in FIGS. 8 and 9, the same or equivalent elements as those in the above-described embodiment are denoted by the same reference numerals. In the following description,
Overlapping description of elements with the same reference numerals is omitted.

The optical fiber amplifier 131 'shown in FIG.
Includes an amplification optical fiber 135 ₁ , a pumping light source 133A for forward pumping and an optical isolator 142A, and a pumping light source 133B for backward pumping and an optical isolator 142B. Further, the optical fiber amplifier 131 ′ includes a wavelength division multiplexer (WDM) 141 and a condenser lens 143.
And a dichroic mirror 144 that transmits light having the wavelength of the amplification target light and reflects light having the wavelength of the excitation light.

In this optical fiber amplifier 131 ', an optical isolator 142A is emitted from the pumping light source 133A.
The forward pumping light that has passed through WDM enters the amplification optical fiber 135 ₁ via WDM and pumps Er added to the amplification optical fiber 135 ₁ . On the other hand, the backward excitation light emitted from the excitation light source 133B and passing through the optical isolator 142B is reflected by the dichroic mirror 144 after passing through the condenser lens 143. Dichroic mirror 14
The backward excitation light reflected by 4 is again collected by the condenser lens 14
After passing through 3, it enters the amplification optical fiber 135 ₁ and
The Er added to the amplification optical fiber 135 ₁ is excited. Thus, when the added Er is amplified light to the amplification optical fiber 135 ₁ excited is incident through the WDM141, traveling through the amplification optical fiber 135 ₁ medium is amplified. Then, the light amplified in the amplification optical fiber 135 ₁ is sequentially emitted through the condenser lens 143 and the dichroic mirror 144.

The light to be amplified is also efficiently amplified by the optical fiber amplifier 131 'like the first optical fiber amplifier 131 of the above embodiment. The first
Optical fiber amplifier 1 instead of the optical fiber amplifier 131
When using 31 ', the second optical fiber amplifier 1
For 32, it is necessary to separately prepare an excitation light source.

The optical fiber amplifier 131 "shown in FIG.
Is different from the optical fiber amplifier 131 'of FIG. 8 only in that optical circulators 137A and 137B are used instead of the optical isolators 142A and 142B. In this optical fiber amplifier 131 ″, the forward pumping light passes through the amplification optical fiber 135 ₁ and then sequentially passes through the condenser lens 143, the dichroic mirror 144, and the condenser lens 143, and then to the terminal b of the optical circulator 137B. Incident,
It is ejected from the terminal c. On the other hand, the backward pumping light enters the terminal b of the optical circulator 137A after passing through the amplification optical fiber 135 ₁ and the WDM 141, and is emitted from the terminal c.

The light to be amplified is also efficiently amplified by the optical fiber amplifier 131 ″ as in the case of the first optical fiber amplifier 131 of the above-described embodiment or the optical fiber amplifier 131 ′ of FIG. 8. When the optical fiber amplifier 131 ″ is used instead of the optical fiber amplifier 131, the backward pumping light emitted from the terminal c of the optical circulator 137A or the forward pumping light emitted from the terminal c of the optical circulator 137B is used. This may be supplied to the second optical fiber amplifier 132.

The second optical fiber amplifier 132 of the above embodiment is also used for the first optical fiber amplifier 13.
A modification similar to the modification to the optical fiber amplifier 131 ′ or the optical fiber amplifier 131 ″ for 1 can be performed.

Further, the configuration of the wavelength conversion section in the above embodiment is an example, and it goes without saying that the configuration of the wavelength conversion section of the present invention, the material of the nonlinear optical crystal, the output wavelength and the like are not limited to this. For example, a fundamental wave having a wavelength of 1.57 μm emitted from the optical amplification unit 163 is subjected to harmonic generation of a 10th harmonic using a non-linear optical crystal, and ultraviolet light of 157 nm having the same wavelength as that of the F ₂ laser is generated. You can also It is also possible to use a CBO crystal when generating the 8th harmonic by the sum frequency generation.

Further, in the above embodiment, the laser light source 1
Although the DFB semiconductor laser is used as the 60A, another semiconductor laser, a fiber laser, or the like can be used.

Further, in each of the above embodiments, the Er-doped fiber is adopted as the amplification optical fiber, but it is also possible to adopt a Yb-doped fiber or other rare earth element-doped fiber.

In the above embodiment, the optical fiber having the core portion added with the rare earth element is used as the amplifying medium. For example, a rod-shaped glass body with the rare earth element added to the core portion is used. It is also possible to irradiate this with excitation light.

Further, the number of the optical fiber amplifiers 167 arranged in parallel in the optical amplifying section 161 may be arbitrary, and the number may be determined according to the specifications required in the product to which the light source device according to the present invention is applied. Good. In particular, when a high output is not required for the light source device, the number of optical fiber amplifiers 167 can be reduced to simplify the configuration. If the optical fiber amplifier 167 is simplified to include only one, the branching device 166 is not necessary.

Further, in the above embodiment, the wavelength of the ultraviolet light emitted from the light source device is set to be substantially the same as that of the ArF excimer laser, but the setting wavelength may be arbitrary and the wavelength should be set to this. According to the laser light source 160A
The oscillation wavelength, the configuration of the wavelength conversion unit 163, the harmonic magnification, and the like may be determined. Note that the set wavelength may be determined according to, for example, the design rule (line width, pitch, etc.) of the pattern to be transferred onto the wafer, and the exposure conditions and the type of reticle described above may be used for the determination. (Phase shift type or not) may be taken into consideration.

In the above embodiment, the case where the light source device according to the present invention is applied to the step-and-scan type scanning exposure apparatus has been described, but it is used in a device manufacturing process other than the exposure apparatus. The light source device according to the present invention can be applied to a device, for example, a laser repair device used to cut a part (a fuse or the like) of a circuit pattern formed on a wafer. Further, the present invention is not limited to a step-and-scan type scanning exposure apparatus, but a static exposure type, for example, a step-and-repeat type exposure apparatus (stepper or the like).
Can also be suitably applied to. Further, it can be applied to a step-and-stitch type exposure apparatus, a mirror projection aligner, and the like.

In the above embodiment, the example in which the light source device according to the present invention is used as the light source device for generating the exposure illumination light has been described. However, the light having the same wavelength as the exposure illumination light is required. As a light source device for the reticle alignment described above, or as a light source device for an aerial image detection system that detects the projected image of a mark arranged on the object plane or image plane of the projection optical system to obtain the optical characteristics of the projection optical system. It is also possible to use.

The light source device of the present invention can be used in various devices other than the exposure device. For example, a light source used for a laser treatment device that irradiates a cornea with laser light to ablate the surface (or ablate the inside of the incised cornea) and correct the curvature or unevenness of the cornea to treat myopia, astigmatism, etc. It can be used as a device. The light source device of the present invention can also be used as a light source device in an optical inspection device or the like.

The light source device of the present invention can also be used for optical adjustment (optical axis alignment, etc.) or inspection of an optical system such as the projection optical system in the above embodiment. Further, in various devices having an excimer laser as a light source, the light source device of the present invention can be applied in place of the excimer laser.

Next, a device (semiconductor chip such as IC or LSI, which uses the exposure apparatus and method of the above embodiment,
Manufacturing of a liquid crystal panel, a CCD, a thin film magnetic head, a micromachine, etc. will be described.

First, in the design step, functional design of a device (for example, circuit design of a semiconductor device) is performed, and pattern design for realizing the function is performed. Subsequently, in a mask manufacturing step, a mask on which the designed circuit pattern is formed is manufactured. On the other hand, in the wafer manufacturing step, a wafer is manufactured using a material such as silicon.

Next, in the wafer processing step, the mask and wafer prepared in the above steps are used to form an actual circuit or the like on the wafer by a lithography technique, as will be described later.

This wafer processing step is, for example, in manufacturing a semiconductor device, an oxidation step for oxidizing the surface of the wafer, and a CV for forming an insulating film on the surface of the wafer.
It has a pretreatment process of each stage of the wafer process such as a D step, an electrode formation step of forming electrodes on the wafer by vapor deposition, an ion implantation step of implanting ions into the wafer, and a post-treatment process described later. The pretreatment process is selected and executed according to the required treatment at each stage of the wafer process.

At each stage of the wafer process, when the pretreatment process is completed, the photoresist is applied to the wafer in the resist processing step, and subsequently, in the exposure step, the circuit pattern of the mask is printed on the wafer by the exposure apparatus 10 described above. Expose. Next, the exposed wafer is developed in the developing step, and subsequently, in the etching step, the exposed member other than the portion in which the resist remains is removed by etching. Then, in the resist removing step, the unnecessary resist after etching is removed.

As described above, by repeating the pretreatment process and the posttreatment process from the resist treatment step to the resist removal step, multiple circuit patterns are formed on the wafer.

When the wafer processing step is completed in this way, the wafer processed in the wafer processing step is used to make chips in the assembly step. This assembly includes steps such as an assembly step (dicing and bonding) and a packaging step (chip encapsulation).

Finally, in the inspection step, inspections such as an operation confirmation test and a durability test of the device manufactured in the assembly step are performed. After these steps, the device is completed and shipped.

As described above, a device in which a fine pattern is formed with high precision is manufactured with high mass productivity.

[0145]

As described in detail above, according to the first and second light source devices of the present invention, it is possible to efficiently generate high-luminance light with a simple structure.

Further, according to the light irradiating device of the present invention, the light emitted from the light source device of the present invention is applied to the object through the irradiation optical system, so that the efficiently generated light is applied to the object. can do.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a configuration of an exposure apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing an internal configuration of the light source device of FIG. 1 together with a main controller.

FIG. 3 is a diagram for explaining the wavelength of light generated by the laser light source of FIG.

FIG. 4 is a block diagram showing a configuration of an optical amplification section in FIG.

5 is a diagram schematically showing a configuration of the optical fiber amplifier of FIG.

FIG. 6 is a diagram for explaining wavelength transmission characteristics of a lossy fiber grating formed in an amplification optical fiber in the first optical fiber amplifier of FIG.

FIG. 7 is a diagram showing a configuration of a wavelength conversion unit in FIG.

FIG. 8 is a diagram for explaining a modification example (1) of the first optical fiber amplifier in FIG.

FIG. 9 is a diagram for explaining a modification (No. 2) of the first optical fiber amplifier in FIG.

[Explanation of symbols]

10 ... Exposure device (light irradiation device), 12 ... Illumination optical system (irradiation optical system), 16 ... Light source device, 131 ... First optical fiber amplifier, 132 ... Second optical fiber amplifier, 133 ...
Excitation light source (excitation light generator), 135 ₁ ... Amplification optical fiber (first amplification optical fiber), 135 ₂ ... Amplification optical fiber (second amplification optical fiber), 136 E ₁ ... Fiber grating element (first 1 fiber type Bragg diffraction grating), 136E ₂ ... Fiber grating element (third fiber type Bragg diffraction grating), 136S ₁ ... Fiber grating element (4th fiber type Bragg diffraction grating), 136S ₂ ... Fiber grating element ( Second fiber type Bragg diffraction grating), 137E ₁ ...
Optical circulator (first optical branching device), 137E ₂ ... Optical circulator excitation light supply device, 137S ₁ ... Optical circulator (third optical branching device), 137S ₂ ... Optical circulator (second optical branching device).

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5F046 BA03 CA03 CA08 CB01 CB04                       CB25 DA01 FA05                 5F072 AB09 AK06 HH04 HH06 JJ02                       KK05 KK07 KK15 MM07 PP07

Claims (13)

[Claims] 1. A light source device comprising: a laser light generator that generates light of a first wavelength; and an optical amplifier that includes at least one optical fiber amplifier that amplifies the light generated by the laser light generator. The first optical fiber amplifier included in the optical amplification unit adds an element excited by light having a second wavelength different from the first wavelength, and amplifies the incident light having the first wavelength. , A Bragg diffraction grating is formed that substantially transmits the light of the first wavelength and the light of the second wavelength and reduces the propagation amount of noise light generated by the amplification of the light of the first wavelength. A first amplification optical fiber; and the second
A pumping light generator for supplying light having the wavelength of 5 to the first amplification optical fiber. 2. A first optical branching device for branching and emitting the light of the second wavelength via the first amplification optical fiber, the optical amplifying section being pumped by the light of the second wavelength A second amplification optical fiber that is added with an element to be amplified and that amplifies the incident light of the first wavelength, and the second amplification light that is emitted from the first optical branching device for the second amplification. The light source device according to claim 1, further comprising: a second optical fiber amplifier including a pumping light supplier that supplies the optical fiber. 3. A light source device comprising: a laser light generator that generates light of a first wavelength; and an optical amplifier that includes a plurality of optical fiber amplifiers that amplify the light generated by the laser light generator. The optical amplification unit is doped with an element excited by light having a second wavelength different from the first wavelength, and a first amplification optical fiber for amplifying incident light having the first wavelength; A first optical fiber amplifier including a pumping light generator that supplies light of two wavelengths to the first amplifying optical fiber as pumping light; and a second wavelength of light that passes through the first amplifying optical fiber. A first optical branching device that splits and outputs light; a second amplification optical fiber to which an element excited by the light of the second wavelength is added and which amplifies the incident light of the first wavelength, The first
The light of the second wavelength emitted from the optical branching device is converted into the second light.
A second optical fiber amplifier including: a pumping light supplier for supplying to the amplification optical fiber; and a light source device further comprising: 4. The light amplification section is provided in the vicinity of an end of the first amplification optical fiber on the side opposite to the incident end side of the light of the second wavelength, and the light of the second wavelength is provided. A first fiber Bragg diffraction grating that reflects light is further provided, and the first optical branching device reflects the light of the second wavelength in the first amplification optical fiber by being reflected by the first fiber Bragg diffraction grating. 4. The light source device according to claim 2, wherein the light of the second wavelength emitted from the incident end of is branched. 5. The second optical fiber amplifier is provided in the vicinity of an end of the second amplification optical fiber opposite to an incident end side of the light of the first wavelength, and the first optical fiber amplifier is provided.
A second fiber type Bragg diffraction grating that reflects light having a wavelength of; and a light reflected by the second fiber type Bragg diffraction grating and emitted from the incident end of the light having the first wavelength in the second amplification optical fiber. The second light branching device for branching the separated light of the first wavelength; and the light source device according to any one of claims 2 to 4. 6. The second optical fiber amplifier is provided near an end of the second amplification optical fiber opposite to an incident end side of the light of the second wavelength, and the second wavelength is provided. The light source device according to any one of claims 2 to 5, further comprising a third fiber type Bragg diffraction grating that reflects the light. 7. The first wavelength is a wavelength in the 1.55 μm band, and the element added to the second amplification optical fiber is erbium. The light source device according to claim 1. 8. The first optical fiber amplifier is provided near an end of the first amplification optical fiber opposite to an incident end side of the light of the first wavelength, and the first optical fiber amplifier is provided.
A fourth fiber-type Bragg diffraction grating that reflects light having a wavelength of; and a light reflected by the fourth fiber-type Bragg diffraction grating and emitted from an incident end of the light having the first wavelength in the first amplification optical fiber. The light source device according to any one of claims 1 to 7, further comprising: a third optical branching device that branches the separated light of the first wavelength. 9. The optical amplifying unit includes a plurality of optical fiber amplifiers connected in series with the first optical fiber amplifier as a final stage. The light source device according to. 10. The first wavelength is a wavelength in the 1.55 μm band, and the element added to the first amplification optical fiber is erbium.
The light source device according to claim 1. 11. The method according to claim 1, further comprising a wavelength conversion unit that converts the light of the first wavelength amplified by the optical amplification unit into light of a third wavelength. The light source device according to claim 1. 12. The first wavelength is a wavelength at which the light of the third wavelength is different from the absorption peak wavelength of the medium component of the optical path of the third wavelength, and is standardized by the International Telecommunication Union. 12. The light source device according to claim 11, wherein the light source device has one wavelength among a plurality of wavelengths that are predetermined. 13. A light irradiation device for irradiating an object with light, comprising: the light source device according to claim 1; and directing light emitted from the light source device toward the object. And an irradiation optical system for emitting light.