JPH10284792A - Laser light source, method and apparatus for exposure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a laser light source which outputs a light having a center wavelength of specified value of less, in which a laser light of a wavelength which is not being absorbed by oxygen is emitted by providing an enclosed optical path, containing oxygen between a pair of resonators disposed on the opposite sides of a laser excitation section. SOLUTION: This laser light source 10 is provided with a laser excitation discharge section 11, an enclosed container 12 containing oxygen and resonators 13a, 13b is arranged on the optical axis p of the laser light source 10. An enclosed optical path containing oxygen and passing a laser light is formed in the enclosed container 12 containing oxygen, while having an optical path length corresponding to the length of the container 12 along the optical axis p. The laser excitation discharge section 11 and the container 12 are provided, respectively, with light transmission windows 11a, 11b and 12a, 12b, and the concentration of oxygen gas in the enclosed container 12 is regulated to a specified level. The light transmission windows can transmit a light, having a center wavelength of 200 nm or less. According to the arrangement, only such light which is not being absorbed by oxygen can be amplified between the resonators 13a, 13b and emitted from an output mirror 13a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser light source for outputting light having a center wavelength of 200 nm or less, an exposure apparatus for transferring a fine circuit pattern onto a substrate such as a semiconductor wafer or a glass plate by light from the light source, and It relates to an exposure method.

[0002]

2. Description of the Related Art In an exposure apparatus and an exposure process for manufacturing a semiconductor device, a liquid crystal device, and the like, in order to form a finer pattern on a substrate, it is advantageous to perform exposure with light having a wavelength as short as possible. ArF which outputs light having a center wavelength of 200 nm or less as a light source for this purpose
Excimer lasers are being considered. However, the oscillation frequency of the ArF excimer laser is around 193 nm, and the intensity of the laser light is attenuated by absorption of oxygen gas in an atmosphere containing oxygen.

In order to use laser light from an ArF excimer laser for such exposure, an optical path from a light source to a substrate to be exposed is sealed, and the sealed optical path is filled with nitrogen having no absorption. It was necessary to replace with a gas such as this or to make the optical path vacuum. In addition, when oxygen gas absorbs laser light in an oxygen atmosphere, harmful ozone gas is generated by photolysis of oxygen, so that it is necessary to seal the portion through which the laser light passes.

[0004]

However, the configuration in which the optical path from the light source to the substrate is sealed, replaced with nitrogen gas, or evacuated, as in the prior art, complicates the configuration of the exposure apparatus. The increase in size leads to an increase in manufacturing costs. Further, every time the exposure apparatus is maintained, the closed space is opened, and after the maintenance, vacuum suction or replacement with nitrogen gas is necessary again, which is very inefficient in adjusting the exposure apparatus.

The present invention solves the above-mentioned problems of the prior art, and has a laser light source capable of utilizing light having a center wavelength of 200 nm or less in an optical path open to the atmosphere, and having a center wavelength of 200 nm or less. It is an object of the present invention to provide an exposure apparatus and an exposure method capable of transferring a predetermined pattern onto a substrate via an optical path opened to the atmosphere by light.

[0006]

The laser light source according to the present invention comprises:
In order to achieve the above object, in a laser light source that outputs light having a center wavelength of 200 nm or less, a sealed oxygen-containing optical path is provided between a pair of resonators sandwiching a laser excitation unit.

According to the present invention, since the laser excitation section is disposed between the pair of resonators and the hermetically sealed oxygen-containing optical path is provided, every time light reciprocates between the pair of resonators during laser oscillation. It passes through a closed oxygen-containing optical path, each time light is absorbed by oxygen. By the way, oxygen has a light absorption band at intervals of 200 nm or less. On the other hand, the intensity of the laser beam has a certain distribution centered on a predetermined wavelength. Therefore, if the laser light source is 2
In the case of outputting light having a center wavelength of 00 nm or less, every time light having a certain intensity distribution reciprocates in the closed oxygen-containing optical path and is amplified, the light is absorbed in the light absorption band by oxygen and the intensity is attenuated. In the frequency band in which oxygen does not absorb light (or does not absorb light), the light intensity is not attenuated. As a result, according to the laser light source of the present invention, the light of the wavelength absorbed by oxygen is greatly attenuated while reciprocating between the pair of resonators, and only the laser light of the wavelength not absorbed by oxygen is supplied to the pair of resonators. It is amplified between and emitted from the laser light source.

Accordingly, since the laser light from the laser light source according to the present invention has a wavelength at which light absorption by oxygen does not occur, the intensity of the laser light is attenuated even when passing through an optical path open to the atmosphere. No harmful ozone gas is generated. Therefore, it is not necessary to seal the optical path from the light source to the substrate to be exposed. Therefore, it is not necessary to replace the sealed optical path with a gas such as nitrogen or to make the optical path vacuum. Also, since the oxygen-containing optical path is sealed, even if ozone gas is generated, it does not leak into the atmosphere.

Such an oxygen-containing optical path can be formed in an oxygen-containing container, and the oxygen-containing container has a light transmitting portion on the optical axis of the laser light source.

In this case, at least one of the pair of resonators can be disposed in the oxygen-containing container, and a laser excitation section can be provided in the oxygen-containing container.

It is preferable that an ozone adsorbing means is provided in the oxygen-containing container because ozone gas generated in the container can be reduced. In particular, when the amount of ozone in the container increases, the light absorption characteristics in the oxygen-containing container change, and the wavelength of light output from the laser light source may change, but this can be prevented.

[0012] Further, by providing an oxygen detecting means provided in the oxygen-containing container and an oxygen concentration control device for controlling the concentration in the oxygen-containing container based on the detection output,
Since the concentration in the oxygen-containing container can be controlled to be constant, fluctuations in light absorption characteristics due to fluctuations in oxygen concentration can be prevented, and light absorption characteristics in the oxygen-containing container can be constant.

Further, by disposing a wavelength selection mechanism between the pair of resonators, the wavelength of light output from the laser light source can be narrowed. Such a wavelength selection mechanism can be constituted by, for example, an etalon, a diffraction grating, a prism, and the like. With this wavelength selection mechanism, the oscillation frequency of the laser light source can be set to a wavelength that is not absorbed by oxygen. Therefore,
It is possible to obtain a laser beam having a wavelength narrowed and not absorbed by oxygen. Also, because the light is narrower,
The laser light itself output from the laser light source may be a small light amount. Therefore, the burden on the optical element such as the diffraction grating constituting the light wavelength selection mechanism is small, and the life of the optical element is prolonged.

The laser light source is provided with means for detecting the light amount of the laser light output from the laser light source, and adjusting the light amount of the output laser light to be constant by a wavelength selecting mechanism based on the detected light amount output. Even if the wavelength of the light output from the device fluctuates and the light amount fluctuates, the wavelength can be adjusted immediately, and stable light with a constant wavelength can be output.

Further, the above-mentioned laser light source is provided.
According to an exposure apparatus that transfers a predetermined pattern onto a substrate using a laser beam having a center wavelength of not more than nm through an optical system, light having a wavelength that is not absorbed by oxygen is output from a laser light source. There is no need to provide an optical path. Therefore, the configuration of the apparatus can be simplified. Further, in the exposure apparatus, when the wavelength of light is as short as 200 nm or less, it becomes difficult to manufacture an achromatic lens, and a monochromatic lens is used as a reduction projection lens of an optical system. Although it is necessary to band, the exposure apparatus according to the present invention is preferable because the laser light source has a wavelength selection mechanism, so that narrow band light can be obtained.

Further, such an exposure apparatus includes a laser light source having the above-described wavelength selection mechanism, and an apparatus-side light amount detecting means provided in an optical system of the apparatus. When the light amount of the laser light output from the laser light source is adjusted based on the wavelength selection mechanism, the wavelength can be immediately adjusted by the wavelength selection mechanism even if the light output from the laser light source changes in wavelength and the light amount changes. . The optical system of the exposure apparatus is designed for a certain wavelength, and this configuration is preferable because the exposure apparatus can perform exposure with light having a stable wavelength.

Further, 200n from the laser light source described above is used.
According to an exposure method of transferring a predetermined pattern onto a substrate via an optical system by a laser beam having a center wavelength of m or less,
Exposure can be performed without passing light through a closed optical path as in the past,
In addition, since there is no need to take measures against ozone gas treatment, the exposure process can be further simplified.

In this exposure method, the step of detecting the amount of laser light from the laser light source having the above-described wavelength selection mechanism in the optical system, and the step of detecting the amount of laser light from the laser light source by the wavelength selection mechanism based on the output of the detection of the amount of light. And the step of adjusting the wavelength can be performed immediately by the wavelength selection mechanism even if the wavelength of light output from the laser light source fluctuates. The optical system used in the exposure process is designed for a certain wavelength, and this configuration is preferable because the exposure process can be performed with light having a stable wavelength.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram schematically illustrating an example of a laser light source according to the present invention. The laser light source 10 shown in FIG. 1 includes a laser-excited discharge unit 11 that seals a laser medium gas therein and includes a pair of discharge electrodes 11c and 11d.
And a sealed oxygen-containing container 12 containing oxygen gas therein, and a pair of resonators 13a and 13b disposed so as to sandwich the laser excitation unit 11 and the sealed container 12 therebetween.
The components 11, 12, 13a and 13b are arranged on the optical axis p of the laser light source 10. A sealed oxygen-containing optical path through which laser light passes is formed in the oxygen-containing container 12, and the optical path length corresponds to the length of the container 12 along the optical axis p.

The laser-excited discharge section 11 has light transmission windows 11a and 11b on both end faces in the direction of the optical axis p. A predetermined voltage is applied to the discharge electrodes 11c and 11d from a power supply (not shown) during laser oscillation. The sealed container 12 is provided with light transmission windows 12a and 12b on both end surfaces in the direction of the optical axis p, and oxygen gas in the sealed container 11 is adjusted to a predetermined concentration. These light transmission windows can be made of a material such as synthetic quartz, but may be any material that can transmit light having a center wavelength of 200 nm or less.

One of the resonators 13a constitutes an output mirror, and the output mirror 13a is disposed so as to be close to and opposed to the light transmission window 12a of the oxygen-containing closed vessel 12.
The sealed container 12 is arranged such that the light transmission window 12b is close to and opposes the light transmission window 11a of the laser excitation discharge unit 11. The other 13b of the resonator forms a reflection mirror,
The reflection mirror 13b is disposed so as to be close to and opposed to the light transmission window 11b of the laser excitation discharge unit 11.

The operation of the above laser light source 10 will be described.
If the laser medium gas in the laser excitation discharge unit 11 of the laser light source 10 is, for example, ArF, an ArF excimer laser light source is configured. FIG. 7 shows a curve (a) representing the intensity distribution with respect to the wavelength of the laser light emitted from the ArF excimer laser light source, and a curve (b) representing the light absorption characteristics of oxygen gas within the intensity distribution of the laser light. This laser beam has a center wavelength near the wavelength of 193.4 to 193.5 nm as shown in the intensity distribution curve (a).
The light absorption characteristic curve (b) has a plurality of peaks and valleys, and in the valley corresponding to the predetermined wavelength, the intensity of the laser beam is reduced due to absorption by oxygen, but the peak corresponds to the predetermined wavelength. It can be seen that there is almost no absorption by oxygen at the peak.

When a predetermined voltage is applied between the discharge electrodes 11c and 11d of the laser-excited discharge unit 11 to excite the laser light source 10, a discharge is generated between the electrodes and stimulated emission of the excited excimer caused by the discharge. By laser light source 1
0 causes pulse oscillation. Thereby, the laser beam is reflected and reciprocates between the pair of resonators 13a and 13b in the optical axis p direction.
Therefore, each time the laser light reciprocates between the pair of resonators 13a and 13b, the laser light passes through the oxygen-containing closed container 12, and the light is absorbed by oxygen each time.

As shown in the light absorption characteristic curve (b) of the ArFe excimer laser light by oxygen in FIG. 7, the laser light is absorbed by oxygen in a plurality of valleys corresponding to a predetermined wavelength and its intensity is attenuated. However, at a plurality of peak portions corresponding to a predetermined wavelength, the intensity of light is not attenuated because the degree of absorption by oxygen is low. As a result, light having a wavelength absorbed by oxygen is greatly attenuated while reciprocating between the pair of resonators 13a and 13b, and only light having a wavelength not absorbed by oxygen is amplified between the pair of resonators 13a and 13b. When the laser light source 10 reaches the oscillation critical state, the laser light is emitted from the output mirror 13a.

Accordingly, since the laser light output from the laser light source 10 shown in FIG. 1 is light having a wavelength at which light absorption by oxygen does not occur, even if it passes through an optical path open to the atmosphere,
The intensity of the laser beam is not attenuated, and no harmful ozone gas is generated.

In the example of FIG. 1, the oxygen-containing closed container 1
2 is disposed between the laser-excited discharge unit 11 and the output mirror 13a.
b, or both.

FIG. 2 shows another embodiment according to the present invention. The laser light source shown in FIG. 2 has the same basic configuration as that shown in FIG. 1 except that a center wavelength selection element 21 is added. The laser light source 20 shown in FIG.
A diffraction grating 21 is disposed as a center wavelength selecting element between the light transmission window 11b and the reflection mirror 13b of the resonator. For this reason, the optical axis p of the laser light source 20 is bent by the diffraction grating 21.

Each time the laser beam reciprocates between the pair of resonators 13a and 13b, it passes through the oxygen-containing closed vessel 12, and each time the laser beam is absorbed by oxygen,
The center wavelength of the light is narrowed to the wavelength set by the diffraction grating 21. Since the set wavelength of the diffraction grating 21 can be set to a wavelength that is not absorbed by oxygen, it is possible to obtain a laser beam having a narrow band and a wavelength that is not absorbed by oxygen.

The diffraction grating 21 is provided with a fine rotation mechanism (not shown). When the wavelength of the laser light output from the laser light source 20 fluctuates, the diffraction grating 21 is finely rotated in the direction r in FIG. The wavelength can be adjusted by changing the inclination of the laser beam with respect to the optical axis p, and the center wavelength of the output laser beam can be kept constant. In addition, an etalon or a prism can be used as the center wavelength selection element. Further, the center wavelength selection element may be arranged between the oxygen-containing closed vessel 12 and the output mirror 13a.

FIGS. 3 and 4 show the laser light sources 10 and 10 described above.
20 shows two other examples of the oxygen-containing closed container at 20. The oxygen-containing closed container 22 shown in FIG. 3 has light transmitting windows 22a and 22b on both end surfaces, and an ozone adsorbing material 22c is provided on the inner surface thereof. The ozone adsorbent 22c can be made of, for example, activated carbon. Ozone gas generated in the container can be reduced by adsorbing ozone gas on the ozone adsorbent 22c. In particular, when the amount of ozone in the container increases, the light absorption characteristics in the oxygen-containing container change, and the wavelength of light output from the laser light source may change, but this can be prevented.

The oxygen-containing closed container 32 shown in FIG. 4 has light transmitting windows 32a and 32b on both end faces, and an oxygen sensor 32c for measuring oxygen concentration inside. The concentration detection signal of the oxygen sensor 32c is sent to an oxygen concentration control device 33 provided outside the container 32 by being communicated with the inside of the container 32 by a pipe 32d, and based on this signal, the oxygen concentration control device 33 An oxygen gas is supplied to adjust the oxygen concentration in the inside, and a gas other than oxygen such as nitrogen is supplied.
Thereby, the oxygen concentration in the oxygen-containing closed container 32 can be made constant, so that the light absorption characteristics of the oxygen-containing closed container 32 can be made constant. Therefore, the wavelength characteristics of the laser light output from the laser light source can be kept constant.

FIG. 5 shows another example of the laser light source according to the present invention. The basic configuration of the laser light source shown in FIG. 5 is the same as that of FIG. 1 except that both the pair of resonators are arranged in the oxygen-containing closed vessel. The laser light source 40 of FIG. 5 includes a pair of discharge electrodes 41c and 41 in which a laser medium gas is sealed inside.
The laser-excited discharge unit 41 provided with d, and the oxygen-containing closed containers 42 and 44 provided on the optical axis p on both sides of the light transmission windows 41a and 41b of the discharge unit 41 are provided.

One end face of the container 42 is provided with a light transmission window 42a, and the other end face is provided with a light transmission window 4a of the laser excitation discharge section 41.
1a is directly joined to the surface. One end of the container 44 is directly joined to the surface of the light transmitting window 41b of the laser excitation discharge unit 41, and the other end is closed. As described above, both the containers 42 and 44 contain a certain concentration of oxygen gas inside in a sealed state. The light transmitting window 4 is provided inside the container 42.
An output mirror 43a is arranged so as to be close to and opposed to 2a. The reflection mirror 43 is provided inside the container 44.
b is arranged. The laser light is transmitted through the light transmitting window 4 of the container 42.
2a.

In the laser light source 40, by applying a predetermined voltage between the pair of discharge electrodes 41c and 41d, light having a wavelength at which light absorption by oxygen does not occur is output as in the case of FIG. Also, a pair of resonators 43a, 43b
Are formed in the closed containers 42 and 44, so that the laser light is transmitted through the light transmitting window 42 of the container 42.
Do not pass through the atmosphere until released from a. For this reason,
Ozone gas is never generated outside.

FIG. 6 shows still another example of the laser light source according to the present invention. The laser light source shown in FIG. 6 has the same basic configuration as that of FIG. 5 except that a laser excitation discharge part and a pair of resonators are arranged in an oxygen-containing closed vessel. The laser light source 50 shown in FIG. 6 includes a laser excitation discharge unit 51 that seals a laser medium gas therein and includes a pair of discharge electrodes 51c and 51d.
, A pair of resonators 53a and 53b, and an oxygen-containing closed container 52 containing the discharge part 51 and the pair of resonators 53a and 53b therein.

One end face of the container 52 is provided with a light transmitting window 52a, and the other end face is closed. The laser-excited discharge unit 51 includes light transmitting windows 51a and 51b on both end faces in the optical axis p direction.
Are provided and arranged in the container 52. A pair of resonators 53a and 53b are also placed on the container 5 so as to sandwich the discharge portion 51.
2 are arranged. The output mirror 53a is
Is disposed so as to be close to and opposed to the light transmitting window 52a,
It is arranged at a predetermined distance from the light transmission window 51a of the laser excitation discharge unit 51. Also, the reflection mirror 53b
Is disposed so as to face the light transmission window 51b of the discharge unit 51. The container 52 contains a certain concentration of oxygen gas inside in a sealed state. The laser light is emitted from the light transmission window 52a of the container 52.

In such a laser light source 50, by applying a predetermined voltage between the pair of discharge electrodes 51c and 51d, light having a wavelength at which light absorption by oxygen does not occur is output as in the case of FIG. Further, according to such a configuration, it is advantageous that the adsorption of the ozone gas in the oxygen-containing container 52 and the adjustment of the oxygen concentration can be performed in one container.

Next, an exposure apparatus having the above-mentioned laser light source will be described with reference to FIGS. FIG. 8 shows FIG.
FIG. 2 is a schematic diagram showing a schematic configuration of an exposure apparatus including the laser light source 20 shown in FIG. The laser light output from the laser light source 20 passes through the half mirror 71, passes through the light intensity equalizing illumination unit 72, is folded by the reflection mirror 73, and irradiates the reticle 75 through the condenser lens 74. The reticle 75 is a mask on which a circuit pattern or the like is drawn. The laser light passing through the reticle 75 forms an image of the circuit pattern on the wafer substrate 77 via the projection lens 76.

The laser light output from the laser light source 20 is
Part of the light is reflected by the half mirror 71 and the light receiving element 78
, And detects the amount of laser light, and sends this detection signal to the control device 79. When the detection signal of the amount of laser light fluctuates, a signal is sent from the control device 79 to the driving device 80, and the driving device 80 rotates and finely moves the diffraction grating 21 in the r direction so that the amount of laser light becomes constant. The optical axis p of the light source
The inclination of the diffraction grating 21 with respect to is changed.

The laser light output from the laser light source 20 is narrowed by the diffraction grating 21. Then, when the wavelength of the narrow band light fluctuates, the amount of light detected by the light receiving element 78 changes. Therefore, by adjusting the inclination of the diffraction grating 21 so that the amount of laser light is constant,
The center wavelength of the output laser light can be controlled to be constant. The optical system such as the projection lens 76 of the exposure apparatus is designed for a constant wavelength, and according to the configuration of the exposure apparatus shown in FIG. 8, exposure is performed on the wafer substrate 77 by stable light having a constant wavelength. It is preferable because it can be performed.

The laser light output from the laser light source 20 is a laser light having a wavelength not absorbed by oxygen.
There is no problem of a decrease in intensity due to the absorption of laser light by oxygen, and no ozone gas is generated. Therefore, it is not necessary to seal the optical system such as the projection lens 76 and replace the optical system with a nitrogen atmosphere or the like as in the related art.

FIG. 9 is a schematic diagram showing another schematic configuration of an exposure apparatus provided with the laser light source 20 shown in FIG.
In the exposure apparatus shown in FIG. 9, a half mirror 81 is disposed between a reflection mirror 73 and a condenser lens 74, light reflected by the half mirror 81 is incident on a light receiving element 82, and the amount of laser light is detected. The detection signal is sent to the control device 79. When the detection signal of the light amount of the laser beam fluctuates, a signal is sent from the control device 79 to the driving device 80, and the driving device 8
A value of 0 causes the diffraction grating 21 to rotate and finely move in the r direction so as to keep the laser beam intensity constant. Therefore, according to the configuration of the exposure apparatus shown in FIG. 9, the same effect as in the case of FIG. 8 can be obtained.

[0043]

According to the present invention, it is possible to provide a laser light source capable of utilizing light having a center wavelength of 200 nm or less in an optical path open to the atmosphere. Also, 20
It is possible to provide an exposure apparatus and an exposure method capable of transferring a predetermined pattern onto a substrate through an optical path opened to the atmosphere by light having a center wavelength of 0 nm or less.

[Brief description of the drawings]

FIG. 1 is a schematic side sectional view showing an example of a laser light source according to the present invention.

FIG. 2 is a schematic side sectional view showing an example of a laser light source provided with a wavelength selection mechanism according to the present invention.

FIG. 3 is a schematic side sectional view showing an example of an oxygen-containing airtight container that can be used in the laser light source shown in FIGS. 1 and 2;

FIG. 4 is a schematic side sectional view showing another example of the oxygen-containing closed container that can be used in the laser light source shown in FIGS. 1 and 2.

FIG. 5 is a schematic side sectional view showing another example of the laser light source according to the present invention.

FIG. 6 is a schematic side sectional view showing another example of the laser light source according to the present invention.

FIG. 7 shows an intensity distribution curve (a) of light output from an ArF excimer laser and a light absorption characteristic curve (b) of oxygen.

FIG. 8 is a schematic diagram showing an example of an exposure apparatus according to the present invention.

FIG. 9 is a schematic diagram showing another example of the exposure apparatus according to the present invention.

[Explanation of symbols]

10, 20, 40, 50 Laser light source 11, 41, 51 Laser excitation discharge part 12, 22, 32, 42, 52, 44 Oxygen-containing closed container 11a, 11b, 12a, 12b Light transmission window 22a, 22b, 32a, 32b Light transmission window 41a, 41b, 42a Light transmission window 51a, 51b, 52a Light transmission window 21 Diffraction grating 22c Ozone adsorption means 32c Oxygen sensor 33 Oxygen concentration control device 13a, 13b A pair of resonators 43a, 43b A pair of resonators 53a, 53b A pair of resonators 71, 81 Half mirror 75 Reticle 76 Projection lens 77 Wafer substrate 78, 82 Light receiving element

Claims (12)

[Claims] 1. A laser light source that outputs light having a center wavelength of 200 nm or less, wherein a sealed oxygen-containing optical path is provided between a pair of resonators sandwiching a laser excitation unit. 2. An oxygen-containing container having a light transmitting portion,
The laser light source according to claim 1, wherein the oxygen-containing optical path is formed in the oxygen-containing container. 3. The laser light source according to claim 2, wherein at least one of said pair of resonators is arranged in said oxygen-containing container. 4. The laser light source according to claim 2, wherein the laser excitation section is provided in the oxygen-containing container. 5. The laser light source according to claim 2, wherein an ozone adsorbing means is provided in the oxygen-containing container. 6. An oxygen detecting device provided in the oxygen-containing container, and an oxygen concentration control device for controlling the concentration in the oxygen-containing container based on the detection output. 5. The laser light source according to 5. 7. The laser light source according to claim 1, wherein a wavelength selection mechanism is arranged between said pair of resonators. 8. The laser light source according to claim 7, further comprising means for detecting a light amount of the output laser light, and adjusting the wavelength of the output laser light by the wavelength selection mechanism based on the light amount detection output. 9. An exposure apparatus comprising the laser light source according to claim 1 and transferring a predetermined pattern onto a substrate by using the laser light via an optical system. 10. An exposure apparatus for transferring a predetermined pattern onto a substrate by a laser beam via an optical system, wherein the laser light source according to claim 7 or 8; a device-side light amount detecting means provided in the optical system; An exposure apparatus, comprising: adjusting a wavelength of laser light output from the laser light source by the wavelength selection mechanism based on a light amount detection output from the apparatus-side light amount detection unit. 11. An exposure method for transferring a predetermined pattern onto a substrate by a laser beam from the laser light source according to claim 1 via an optical system. 12. An exposure method for transferring a predetermined pattern onto a substrate by means of a laser beam via an optical system, wherein the optical system detects the amount of laser light from a laser light source according to claim 7 or 8; Adjusting the wavelength of the laser light from the laser light source by the wavelength selection mechanism based on the light quantity detection output.