JP2000223408A - Semiconductor manufacturing apparatus and semiconductor device manufacturing method - Google Patents

Abstract

(57) [Problem] To provide an exposure apparatus with low running cost and suppressed speckle noise. Kind Code: A1 A seed light having a wavelength of 193 nm passes through a beam width expander, and has a cross section elongated in a vertical direction, and then enters a step-shaped transparent member. The laser beam L4 emitted from the transmissive member 7 is an ArF excimer laser 4
To the exposure machine main body 2 and used for exposure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor manufacturing apparatus and a semiconductor device manufacturing technique, and more particularly to an exposure light source which is a light source for photolithography.

[0002]

2. Description of the Related Art There are various types of performance required for an exposure apparatus or a stepper used in a photolithography process, such as resolution, alignment accuracy, processing capability, and apparatus reliability. Among them, the resolution R directly leading to pattern miniaturization is R = k · λ / NA (where,
k is a constant, λ is the exposure wavelength, and NA is the numerical aperture of the projection lens. ). Therefore, in order to obtain good resolution, the optical parameter called the exposure wavelength λ is an important factor.

In a general exposure apparatus, an i-line (wavelength: 365 nm) of a mercury lamp or a KrF excimer laser oscillator having a wavelength of 248 nm is used as an exposure light source. An exposure apparatus using a KrF excimer laser oscillator as a light source is hereinafter referred to as a KrF exposure machine.

As a next-generation photolithography technology,
In an exposure apparatus for performing finer processing, a wavelength 19
An exposure apparatus using a 3 nm ArF excimer laser oscillator as a light source has been studied. Such an exposure apparatus is generally called an ArF exposure apparatus, but in this specification, an exposure apparatus that uses ultraviolet light having a wavelength of 193 nm as exposure light is called an ArF exposure apparatus.

[0005] The ArF exposing machine has a light source that generates ultraviolet light having a wavelength of 193 nm by wavelength conversion based on a solid-state laser or the like (hereinafter, referred to as a light source by wavelength conversion) in addition to a type using an ArF excimer laser itself as an oscillator. .)
A type using an injection locking method using an ArF excimer laser in combination without using a light source by wavelength conversion as an exposure light source is known.

As a typical configuration of a light source by wavelength conversion, for example, a report of a meeting of the Laser Society of Japan, RTM-98
-36, p29 to p34. First, laser light of a Nd: YAG laser oscillating at a wavelength of 1064 nm (a solid-state laser in which neodymium is added to a crystal represented by a composition formula of Nd: Y ₃ Al ₅ O ₁₂ ) is emitted three times. The conversion generates a fifth harmonic having a wavelength of 213 nm. Further, the fifth harmonic and N
d: Fundamental wave of YAG laser (that is, wavelength of 1064 nm)
Laser light) to OPO (Optical Parametric Oscillati)
This is a type of wavelength conversion called on, and is a method of generating laser light having a wavelength longer than the incident light. )) And the infrared light of about 2.1 μm converted to the longer wavelength side with Cs
A sum frequency (hereinafter referred to as SFM: Sum Frequency Mixing) is generated by LiB ₆ O ₁₀ crystal (hereinafter referred to as CLBO) or the like to obtain ultraviolet light having a wavelength of 193 nm.

[0007] Other examples of a light source based on wavelength conversion are described in, for example, SPIE Vol. 3051, pp. 882-889, or Laser Focu.
s World January 1998, pp.113-118.
Regarding OPO, for example, laser research,
1, No. 2, pp. 295-304.
Further, CLBO is described in, for example, Laser Research, Vol. 26, No. 3, pp. 215-219, 1998.

A type using an injection locking method in combination with an ArF excimer laser without directly using a light source by wavelength conversion as an exposure light source is disclosed, for example, in the 59th Annual Meeting of the Japan Society of Applied Physics, Proceedings, 950 Page, 17-
a-P2-1, 1998. That is, laser light having a wavelength of 193 nm from a light source by wavelength conversion is injected into an ArF excimer laser as seed light.

[0009] Among the exposure apparatuses, a scan type exposure apparatus is known. A scan type exposure apparatus is an exposure apparatus that exposes a reticle on which a circuit pattern is drawn and a wafer while moving the reticle, and scans the reticle and the wafer while transferring a part of the reticle through an exposure lens. Thus, the pattern of the entire reticle is transferred to the wafer. Regarding the scanning type exposure machine, for example, Electronic Materials, March 1995, First
This is described on pages 07 to 111.

[0010]

In the type using an ArF excimer laser itself as an oscillator, there is a problem that the running cost becomes high. Since the wavelength band of the output light is wide in the oscillation of the ArF excimer laser itself, it is necessary to narrow and stabilize the wavelength in order to use it for photolithography. However, there is a problem that a band-narrowing element used for generating a laser beam having a narrow wavelength width and a monitor for stabilizing a wavelength are deteriorated in a short period of time. In many cases, expensive materials such as calcium fluoride are used for the band-narrowing element and the wavelength stabilizing monitor, and frequent replacement due to deterioration increases running costs.

The reason for the severe deterioration is that the wavelength of the laser beam is 193 nm and belongs to the vacuum ultraviolet region, and therefore, in general, the absorption rate of many optical materials is high. Therefore, even if a material having a transmittance in the vacuum ultraviolet region such as calcium fluoride is used, when it is irradiated with a laser beam of 193 nm, it absorbs the laser beam having a large power density and gradually changes its composition, causing serious damage. Because it leads.

Therefore, a light source based on wavelength conversion is studied instead of the ArF excimer laser oscillator. In the light source by this wavelength conversion, the laser light of a long wavelength before the wavelength conversion can be narrowed and the wavelength can be further stabilized, so that deterioration of the band narrowing element and the wavelength stabilization monitor hardly occurs. From this, a reduction in running cost can be expected.

However, the light source based on the wavelength conversion has two main problems as described below. That is,
This is a point where the generation of speckle noise and the output are small. The speckle is a speckled pattern that appears on the observation surface of the laser light,
When used for photolithography, a problem arises as unevenness in irradiation density.

The reason that speckle noise is easily generated in a light source by wavelength conversion is that, unlike a normal excimer laser oscillator, a light source by wavelength conversion is a single mode beam with a small beam divergence angle in order to increase the efficiency of wavelength conversion. Must be used. However, the coherence of a single mode beam is high, and speckle is likely to occur in a highly coherent laser, so that speckle noise is likely to occur.

In some cases, not only a light source based on wavelength conversion but also an excimer laser oscillator requires a measure for suppressing speckle noise. In order to suppress this, there is a method of averaging the pattern irradiated on the wafer by superimposing a number of pulses (that is, superposing the pulses). However, when it is necessary to superimpose a large number of pulses, the throughput is reduced by the superimposed amount. In particular, since the scanning speed cannot be increased in a scan type exposure apparatus, the throughput as the exposure apparatus decreases. .

The second problem of the light source by the wavelength conversion is that the laser output is only about 0.2 W (1-2% of the output of the fundamental wave), and the high output of 5 W or more required as an exposure light source is obtained. Is difficult.

The main reason is that, as described above, in the conventional light source configuration using wavelength conversion, it is necessary to perform wavelength conversion five times before finally generating a wavelength of 193 nm. Since the laser output is reduced by half or less each time the wavelength conversion is performed, the output of ultraviolet light having a wavelength of 193 nm becomes less than 1 W even when a Nd: YAG laser of several tens of W class is used. Still another reason for the low output is that the wavelength width of the infrared light generated by the OPO is too wide and the efficiency in performing the SFM is low. That is, although OPO can convert laser light to an arbitrary wavelength to some extent, on the other hand, the wavelength width may be as large as several nm or more, or the center wavelength may fluctuate greatly.

As described above, in order to obtain a laser beam having a wavelength of 193 nm with an output of 5 W from a light source by wavelength conversion, an output of 200 to 300 W is required on the assumption that an Nd: YAG laser is used. . At present, it is difficult to oscillate such a fundamental wave exceeding 100 W in a single mode. To perform wavelength conversion, it is necessary to make the fundamental wave incident on the nonlinear optical crystal.
Injecting a high-power laser beam exceeding 00 W into the nonlinear optical crystal is a problem because heat is generated in the nonlinear optical crystal. As described above, in the light source by the wavelength conversion, high output is an issue.

An object of the present invention is to provide an exposure light source capable of suppressing speckle noise in a light source based on wavelength conversion.

Another object of the present invention is to provide a low-cost running light source using a light source based on wavelength conversion, which can easily achieve high output.

Another object of the present invention is to reduce the cost of manufacturing a semiconductor device by reducing the cost of an exposure light source.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0023]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows.

(1) A semiconductor manufacturing apparatus according to the present invention includes: a semiconductor manufacturing apparatus having a laser light generating means using wavelength conversion, and an injection-locked ArF excimer laser using light generated by the laser light generating means as seed light. An apparatus, wherein a translucent member is disposed in an optical path between a laser light generating means and an ArF excimer laser, and a seed light in the translucent member has a different passing distance in a beam plane. .

A semiconductor manufacturing apparatus according to the present invention includes a laser light generating means using wavelength conversion, and an injection-locked ArF excimer laser using light generated by the laser light generating means as seed light. Wherein a light-transmitting member is disposed in an optical path between the laser light generating means and the ArF excimer laser, and the phase of the seed light at the light-transmitting member emission end face is different in the beam plane of the seed light. is there.

According to such a semiconductor manufacturing apparatus,
The passing distance inside the transmissive member changes depending on the position in the beam cross section, and the phase of the laser beam emitted from the transmissive member becomes non-uniform, or the phase in the beam cross section at the transmissive member emission end face is uniform. Since it disappears, the coherence is reduced. If the coherence is reduced, speckle noise can be reduced.

Also, since the beam incident on the transmissive member is seed light, even if there is a reflection loss at the input / output end of the transmissive member, the power is amplified by passing the laser through an ArF excimer laser thereafter. And exposure light with sufficient power can be obtained.

Moreover, since the beam incident on the transmissive member is seed light, the beam can be made sufficiently small in energy, so that the transmissive member is prevented from being damaged and deteriorated.

In the semiconductor manufacturing apparatus, the light-transmitting member may be one in which a plurality of light-transmitting member pieces having different dimensions in the optical path direction are arranged one-dimensionally or two-dimensionally. The translucent member pieces having different dimensions in the direction are arranged circumferentially, and the translucent member can be rotatable around the center of the circumference. By making the translucent member such a configuration, the transit distance of the translucent member in the beam plane is made different, and the phase of the transmissive member emission end face is made different to reduce coherence. Speckle noise can be suppressed.

(2) A semiconductor manufacturing apparatus according to the present invention includes: a semiconductor manufacturing apparatus having a laser light generating means using wavelength conversion, and an injection-locked ArF excimer laser using light generated by the laser light generating means as seed light. An apparatus, wherein the seed light comprises a plurality of beams.

If the seed light is composed of a plurality of beams, the phases of the plurality of beams are different from each other, unless otherwise synchronized, so that exposure light with low coherence can be obtained. Moreover, a plurality of beams are ArF
Before passing through the excimer laser, it is necessary to form a single parallel beam. Even if there is some loss in laser power during the coupling, use this as seed light instead of using it for exposure as it is. Therefore, the laser output taken out of the ArF excimer laser can be hardly reduced. FIG. 11 is a graph showing a change in the ArF excimer laser output depending on the seed light power. As shown in the figure, the injection-locked ArF excimer laser has a characteristic that the laser output obtained from the ArF excimer laser hardly changes if the power of the seed light is higher than a certain level.

In the semiconductor manufacturing apparatuses of the above (1) and (2), the seed light has a rectangular cross-sectional shape, and the resonator of the ArF excimer laser can be constituted by a plurality of plane mirrors. In such a case, the gas flow in the ArF excimer laser is caused to flow in the short side direction of the rectangular cross section, so that the efficiency of gas exchange from the discharge region can be increased and the number of laser oscillation repetitions can be increased.

(3) The semiconductor manufacturing apparatus of the present invention
A semiconductor manufacturing apparatus comprising: a laser beam generating unit; and an injection-locked ArF excimer laser using light generated by the laser beam generating unit as seed light, wherein the laser beam generating unit includes first and second neodymium-doped. A solid state laser, and the seed light is 0.9 μm of the first neodymium-doped solid state laser.
The sum frequency of the fourth harmonic of the band fundamental wave and the 1.0 μm band fundamental wave of the second neodymium-doped solid-state laser.

In the semiconductor manufacturing apparatus, the first
Is a Nd: YAG laser, and the second neodymium-doped solid laser is Nd: YA.
The laser may be any one selected from a G laser, a Nd: GSGG laser, a Nd: LMA laser, and a Nd: CaWO ₄ laser.

As a neodymium-doped solid-state laser, for example, N
d: If a YAG laser is used, the wavelength of the oscillation line in the 0.9 μm band is 946 nm, and the wavelength is 1.0 μm.
Since the wavelength of the oscillation line in the band is 1064 nm,
The SFM of the wavelength 236.5 nm, which is the fourth harmonic generated by converting the wavelength of the 6-nm laser light twice, and the SFM of the wavelength 1064 nm are 193.5 nm. So this is A
It can be used as seed light for rF excimer laser. In addition, the number of times of wavelength conversion is three times in total, and laser light oscillated from a solid-state laser is directly used as the long-wavelength infrared light used in performing SFM, instead of OPO. Therefore, since the wavelength width is not widened, the efficiency of the SFM does not decrease and the wavelength does not change.

(4) The method of manufacturing a semiconductor device according to the present invention
Forming a photoresist film having sensitivity in the 0.19 μm band, and exposing the photoresist film with an injection-locked ArF excimer laser beam using a laser beam generated using wavelength conversion as a seed beam. In the method of manufacturing a semiconductor device having a first configuration, when seed light is injected into an ArF excimer laser, a first configuration in which the phase is different in a beam cross section, and the seed light is 0.1 mm of the first neodymium-doped solid-state laser. It has any one of the second configuration which is the sum frequency of the fourth harmonic of the 9 μm band fundamental wave and the 1.0 μm band fundamental wave of the second neodymium-doped solid-state laser.

[0037] Incidentally, the the oscillation line of wavelength 0.9μm band, indicating spectroscopically is that of laser light based from ⁴ F _3/2 to the transition ⁴ I _9/2, also the wavelength 1 0.0 μm
The oscillation line of the band, is that of the laser light based from ⁴ F _3/2 to the transition ⁴ I _11/2.

The Nd: GSGG laser is a solid-state laser represented by a composition formula of Nd: Gd ₃ Sc ₂ Ga ₃ O ₁₂ .

[0039]

Embodiments of the present invention will be described below in detail with reference to the drawings. In all the drawings for describing the embodiments, members having the same functions are denoted by the same reference numerals, and the repeated description thereof will be omitted.

(Embodiment 1) FIG. 1 is a configuration diagram showing an example of an exposure apparatus which is an embodiment of a semiconductor manufacturing apparatus according to the present invention. The exposure apparatus of the present embodiment includes an exposure light source 1, and the exposure light source 1 includes a seed light oscillator 3, an ArF excimer laser 4, and an optical system for guiding the seed light to the ArF excimer laser 4.

The seed light oscillator 3 is, for example, Nd: YA
This is a laser oscillator that converts the wavelength of the fundamental wave of the G laser and generates 193 nm ultraviolet light as seed light. Since the Nd-doped solid-state laser is used, the seed light has a sufficiently narrow band, and is excellent in stability of the center wavelength.

The wavelength 1 extracted from the seed light oscillator 3
93 nm laser light (hereinafter referred to as seed light) L1
Passes through a beam width expander 5 composed of two cylindrical lenses 5a and 5b, and becomes a seed light L2 having a cross section elongated in the vertical direction, and mirrors 6a and 6b
Then, the light is reflected as the seed light L3, and is incident on the transmissive member 7.

As shown in FIG. 1, the permeable member 7
It has a step-like shape, and the seed light L3 incident thereon
Is perpendicularly incident on the left surface of the transmissive member 7. on the other hand,
Since the surface of the transmissive member 7 from which the seed light L4 is emitted is a stepped surface, the light is emitted perpendicularly to the surface of each step of the step. Therefore, the emitted seed light L4 is not refracted and is parallel to the seed light L3. However, since the distance that travels inside the transmissive member 7 differs at positions within the beam cross section, the phase of the emitted seed light L4 differs for each of the steps. Therefore, the seed light L
In No. 4, the phase varies in the beam cross section, and the coherence decreases. In particular, in the present embodiment, the coherence decreases in the X direction shown in the figure.

Strictly speaking, a difference in the transit distance in the transmissive member 7 within the beam cross section does not cause a phase difference, but the refractive index of the air in which the transmissive member 7 is disposed and the transmissivity. If the refractive index of the conductive member 7 is different, a phase difference will occur. However, in practice, if a normal optical material is used as the transmissive member 7, the refractive index is 1.4 to 1.7, which is significantly different from 1.0 of air, and thus a phase difference occurs.

The transmissive member 7 has only to have a high transmissivity for light having a wavelength of 193 nm and satisfy the above-mentioned condition of the refractive index. For example, a crystal in which ionic bonds such as calcium fluoride (CaF) and lithium fluoride (LiF) are dominant, synthetic quartz glass, aluminum oxide crystal (sapphire), and the like can be used.

The seed light L4 is an ArF excimer laser 4
, Where the laser light L5 with increased power is extracted. The laser beam L5 is incident on the exposure machine main body 2,
Used for exposure. In addition, as for the power of the laser beam L5, generally, if the power of the seed beam L4 is a certain level or more, a constant power can be obtained without depending on the power of the seed beam L4.

As described above, in the exposure light source 1 of the present embodiment, since the coherence of the laser light L5 extracted as the exposure light is low, when the exposure light source 1 This has the effect of reducing noise.

Further, since it becomes difficult to form an anti-reflection film on the transmissive member 7, particularly on the stepped emission end face, reflection loss occurs, and the power of the seed light L4 becomes lower than that of the seed light L3. Sometimes. However, in the present invention, since the seed light L4 emitted from the transmissive member 7 is passed through the ArF excimer laser 4, the power is amplified. Therefore, sufficient power is obtained as the laser light L5 used in the exposure apparatus main body 2. Can be

It is a significant feature of the exposure light source 1 of the present embodiment that the coherence of the high power laser beam L5 is reduced by lowering the coherence of the low power seed light L3. That is, since the transmissive member 7 that acts to reduce the coherence is handled at the stage of the seed light L3 having a small power, the transmissive member 7 does not deteriorate in a short time due to the irradiation of the seed light. Thereby, the life of the exposure light source 1 can be extended.

The reason why the seed light L1 extracted from the seed light oscillator 3 is expanded into a beam having a rectangular cross section by the beam width expander 5 as in this embodiment is that the seed light L1 is incident on the transmissive member 7. This is because the beam passes through many steps of the step-like portion. However, in addition to this, when the seed light L4 is injected into the ArF excimer laser 4, the cross-sectional shape of the discharge region (not shown) in the ArF excimer laser 4 can be elongated.
Thus, even when the pulse repetition number of the laser light is increased, the ArF excimer laser 4 can stably discharge each pulse of the laser light. That is, if the number of pulse repetitions is increased, it is necessary to increase the flow rate of the laser gas passing through the discharge region. In this case, the narrower the cross-sectional shape of the discharge region, the higher the flow rate.

Next, A in the exposure light source of this embodiment
The resonator configuration of the rF excimer laser 4 will be described with reference to FIGS. FIG. 2 is a top view of a resonator configuration showing a comparative example studied by the inventor, and FIG. 3 is a perspective conceptual view showing a resonator configuration of the present embodiment.

The resonator configuration of the comparative example shown in FIG. 2 is a generally used injection-locked excimer laser resonator. As shown in the figure, the seed light L8 is composed of a concave mirror 8 with holes and a convex mirror 9 constituting a resonator, and a discharge tube 10 is arranged between them. Windows 11 a and 11 b are attached to both sides of the discharge tube 10. The seed light L8 is injected into the resonator from the concave mirror 8 with holes, passes through the discharge tube 10 once, is reflected by the convex mirror 9 and is reflected again, passes through the discharge tube 10 again, hits the concave mirror 8 with holes, and discharges the discharge tube again. 10 and the laser light L from around the convex mirror 9
It emits as 9. That is, the seed light L8 is
It is amplified by proceeding three times in one way.

On the other hand, since the ArF excimer laser 4 of the present embodiment is used as an exposure light source, the repetition rate is particularly high at 1 kHz or more. As a result, it is advantageous for the discharge region in the discharge tube to have a narrow width in the direction in which the laser gas flows perpendicular to the discharge direction. The reason is that
This is because the laser gas passing between the discharge electrodes needs to flow away from the discharge region during the pulse interval, so that the pulse interval becomes shorter as the number of repetitions increases.

However, in the cavity of the injection-locked excimer laser of the comparative example as shown in FIG. 2, the seed light spreads while reciprocating in the discharge tube to form a circular beam (laser light L9) having a large diameter. Therefore, in order to efficiently amplify this, it is necessary to set the width in the sectional shape of the discharge region to at least the diameter of the laser beam L9. Therefore, the difficulty of operating at a high repetition rate increases.

Therefore, in the ArF excimer laser 4 of the present embodiment, as shown in FIG. 3, the two plane mirrors 12a and 1 are used as resonators sandwiching a discharge tube (not shown).
2b are configured to face each other. This allows the seed light L4 injected into the discharge tube to pass through the discharge region three times in one direction while keeping the rectangular cross section narrow in the Y direction in FIG. 3, thereby enabling operation at a high repetition rate. It will be easier.

As described above, the A used in the present invention
As the resonator configuration of the rF excimer laser, in addition to the combination of the two plane mirrors 12a and 12b as shown in FIG.
Any form of resonator is applicable.

In the above description, the pair of plane mirrors 12
Although a single reciprocating resonance configuration is shown by the combination of a and 12b, it is also possible to adopt a resonance configuration in which a large number of plane mirrors are combined to reciprocate a large number.

Next, FIG. 4 shows the configuration of the exposure machine main body 2 that can be employed in this embodiment. FIG. 4 is a perspective view showing a scan type exposure machine applicable to the semiconductor manufacturing apparatus of the present embodiment. The scan type exposure apparatus of the present embodiment includes an illumination system 41, a reticle scan stage 42, a projection lens 4
4. A reticle 43 having a wafer scan stage 45
Is held by the reticle scan stage 42 and the wafer 4
6 is held on a wafer scan stage 45. The laser beam L5 generated by the exposure light source 1 is incident on the illumination system 41, and is incident on the optical system 48 after changing the optical axis by the mirror 47. The laser light emitted from the optical system 48 is applied to the illustrated illumination area, passes through the reticle 43, and passes through the projection lens 4
4 irradiates the wafer 46. In this scanning type exposure apparatus, the reticle 43 and the wafer 46 reciprocate in the illustrated Y direction. As a result, speckle noise is reduced in the Y direction by superimposing pulses.
On the other hand, in the X direction, the coherence is low as shown in FIG. Therefore, speckle noise is reduced in both the X direction and the Y direction.

(Embodiment 2) FIG. 5 is a perspective view showing another example of the transmissive member used in Embodiment 2. FIG.
The transmissive member 20 shown in FIG. 5 is a further extension of the function of the transmissive member 7 shown in FIG. That is, as shown in FIG. 5, since the unevenness is two-dimensional, the phase in the cross section of the laser beam passing therethrough can be made two-dimensionally different. In order to form the permeable member 30, a large number of narrow prismatic calcium fluoride rods having different lengths may be bundled.

When the phases are two-dimensionally dissimilar, as in the case of the transmissive member 20, it is relatively difficult to construct the transmissive member 20 compactly. To the transparent member 2
After emitting 0, the beam may be reduced based on the beam cross-sectional area and incident on an ArF excimer laser.

In addition, if the exposure light source using the transmissive member 20 is used in the scan type exposure apparatus as described in the first embodiment, the coherence can be reduced in the scanning direction (Y direction). As a result, the number of pulses to be superimposed to cancel speckle noise can be reduced, so that the scanning speed can be increased and the throughput as an exposure apparatus can be increased.

(Embodiment 3) FIG. 6 is a perspective view showing another example of the transparent member used in Embodiment 3. In FIG.
As shown in FIG. 6, the transmissive member 30 shown in FIG. 6 is a disk on which a number of elongated translucent triangular plates are evenly attached, and is rotatable about a rotation shaft 31. It has become something. That is, since the thickness of the portion where the triangular plate 30a is attached increases, the other portions 30a
Compared with b, the passing distance of the incident laser light L3 is different. As a result, as shown in FIG. 6, the phase of the laser beam L4 emitted from the transmissive member 30 varies in the beam cross section.

Further, since the transmitting member 30 rotates at high speed around the rotation axis 31 as shown by the arrow in FIG. 6, the place where the phase is disturbed constantly changes. Therefore, it is possible to change the phase during one pulse of the laser light.
The effect of suppressing speckle noise in pulses is large.

(Embodiment 4) FIG. 7 is a conceptual diagram showing a seed light generating method according to Embodiment 4, and FIG. 8 is a configuration diagram showing a seed light generating means according to Embodiment 4. .

The seed light generating method according to this embodiment is based on the first neodymium-doped solid-state laser, ie, Nd: YA.
A laser beam having a wavelength of 946 nm based on the transition from ⁴ F _3/2 to ⁴ I _9/2 in the G laser is _converted to BBO (more precisely, β-B
A crystal designated as aB ₂ O ₄ . ) Using 473n
A second harmonic, m, is generated. However, instead of BBO, LBO (accurately, a crystal indicated as LiB ₃ O ₅ ) or CLBO can be used.

Next, the second harmonic having a wavelength of 473 nm is further passed through a BBO crystal to generate a second harmonic having a wavelength of 473 nm, that is, a fourth harmonic having a wavelength of 236.5 nm.

Next, when the Nd: YAG laser which is the second neodymium-doped solid-state laser is used, the wavelength of 236.
A fourth harmonic is 5 nm, Nd: wavelength based on the transition from the ⁴ F _3/2 in YAG laser ⁴ I _11/2 ¹⁰⁶⁴ⁿ
By passing m laser light through CLBO, a sum frequency thereof is generated. Since this has a wavelength of 193.5 nm, it can be used as seed light for an ArF excimer laser.

As described above, the exposure light source according to the present embodiment is characterized in that the seed light is generated by performing the wavelength conversion three times, and the number of times of the wavelength conversion is compared with the case described in the related art. Is reduced twice, and as a result, high output can be easily achieved. That is, as the wavelength conversion is repeated, the energy of the output light decreases, but in the present embodiment, the number of wavelength conversions is small, so that the output light is less attenuated and higher output can be achieved.

Further, the present embodiment is characterized in that the OPO is not used. Because OPO is not used, SFM
Is high, the seed light with high output is easily obtained, and the wavelength does not fluctuate.

In FIG. 7, an Nd: YAG laser is used as the second neodymium-doped solid-state laser, but an Nd: GSGG laser may be used. In that case,
⁴ wavelength by the transition from F _3/2 ⁴ I _11/2 1061nm
Laser light oscillates, and this and the wavelength 236.5
UV light having a wavelength of 193.4 nm is generated by the SFM with nm. This can also be used as seed light for the ArF excimer laser.

Further, as a neodymium-doped solid-state laser, N
d: LMA (composition formula is represented by LaMgAl ₁₁ O)
When a laser is used, the laser oscillates at a wavelength of 1053 nm due to the transition from ⁴ F _3/2 to ⁴ I _11/2.
The FM generates ultraviolet light having a wavelength of 193.1 nm, which can also be used as seed light for an ArF excimer laser.

[0072] In addition, Nd: CaWO ₄ laser also ⁴ F
_{Since the} laser oscillates at a wavelength of 1065 nm or 1058 nm due to the transition from _3/2 to ⁴ I _11/2 , S
The FM generates ultraviolet light having a wavelength of about 193 nm, which can be used as seed light.

As described above, there are various types of second neodymium-doped solid-state lasers, and these have a wavelength of 1.0 nm.
Since the oscillation wavelength in the μm band is slightly different,
The wavelength of the ultraviolet light obtained by FM can be finely adjusted. Therefore, it is possible to select a wavelength at which particularly high efficiency can be obtained in the ArF excimer laser.

Next, a specific example of the configuration of the light source by wavelength conversion according to the present embodiment will be described with reference to FIG. The seed light generating means of the present embodiment can be applied to the seed light oscillator 3 of the exposure light source 1 of the first embodiment. Hereinafter, a case where the present invention is applied to the seed optical oscillator 3 of the first embodiment will be described.

The seed light oscillator 3 uses an Nd: YAG laser 101 as a neodymium-doped solid-state laser. That is, a resonator is constituted by the total reflection mirror 103 and the output mirror 104 arranged on both sides of the Nd: YAG crystal 102. Here, the Nd: YAG crystal 102 is excited by a semiconductor laser (not shown). Thus, the laser beam L10 from the Nd: YAG laser 101
Is taken out. However, in the Nd: YAG laser 101, the Q switch 105 is disposed in the resonator, whereby the laser beam L10 operates at a repetition rate of 1 kHz.

The Nd: YAG laser 101 has a reflectivity of almost 100% at a wavelength of 946 nm so that the laser can be strongly oscillated particularly at 946 nm in the 0.9 μm band. ,Also,
90% at a wavelength of 946 nm in the output mirror 104
It has the above-mentioned reflectance. Furthermore,
The Nd: YAG crystal 102 is cooled to minus 30 degrees, so that the gain at the wavelength of 946 nm is increased. In addition, regarding oscillation of laser light having a wavelength of 946 nm from an Nd: YAG laser,
For example, Applied Physics Letters, Volume 15, Number
4, pp. 111-112, 1969.

However, the laser beam L10 extracted from the Nd: YAG laser 101 contains a laser beam having a normal wavelength of 1064 nm in addition to the wavelength of 946 nm. Then, the laser beam L10 first strikes the dichroic mirror 106a, and the laser beam having a wavelength of 946 nm is reflected and travels like a laser beam L11, and the laser beam having a wavelength of 1064 nm passes and travels like a laser beam L12.

The laser beam L11 having a wavelength of 946 nm is focused on the nonlinear optical crystal 109a through the lens 108a. As a result, the wavelength 473 nm, which is the second harmonic, is obtained.
Is generated. The nonlinear optical crystal 10
As 9a, for example, LBO, BBO, or CLBO
Is suitable.

However, the laser beam L13 has an unconverted wavelength of 9
46 nm laser light (hereinafter referred to as a residual fundamental wave) is also included. Therefore, the laser beam L13 is
Through the dichroic mirror 10
6b. The residual fundamental wave is reflected by the laser beam L1
It proceeds like 4 and is stopped by the absorbing plate 110.

The laser beam L13 having a wavelength of 473 nm transmitted through the dichroic mirror 106b is focused on the nonlinear optical crystal 109b through the lens 108c. As a result, a laser beam L15 having a wavelength of 236.5 nm, which is the second harmonic, is generated. BBO is suitable as the nonlinear optical crystal 109b. The laser beam L15 returns to the parallel beam through the lens 108d, and is returned to the dichroic mirror 106.
c.

On the other hand, the laser beam L12 having a wavelength of 1064 nm extracted from the Nd: YAG laser 101 is reflected by the mirrors 107a and 107b and enters the dichroic mirror 106c.

The dichroic mirror 106c has a wavelength of 2
It has a high transmittance of 99% or more in 36.5 nm ultraviolet light, and 99% in infrared light of wavelength 1064 nm.
% Or higher. As a result, in the dichroic mirror 106c, the wavelength 23
The 6.5 nm laser light L15 and the 1064 nm wavelength laser light L12 are synthesized, and proceed like the laser light L16.

The laser beam L16 is focused on the nonlinear optical crystal 109c through the lens 108e. Here, wavelength 2
SFM of the 36.5 nm laser light and the 1064 nm wavelength laser light is performed. Thereby, the wavelength of 193.5n
m laser light L17 is generated. Nonlinear optical crystal 109
CLBO is suitable as c. The laser beam L17 returns to a parallel beam through the lens 108f. This laser light L1
7 is used as seed light.

In this embodiment, as described above, since the Nd: YAG laser 101 performs a repetitive operation at 1 kHz, the laser beam L17 operates at 1 kHz. This is the same as the number of repetitions of the ArF excimer laser 4 shown in FIG. 1 and is synchronized.

As described above, the seed light oscillator 3 of the present embodiment is characterized in that ultraviolet light having a wavelength of 193 nm can be generated by three wavelength conversions by three nonlinear optical crystals, and thus, high output of the seed light is achieved. In addition to simplifying the operation, the frequency of replacing the nonlinear optical crystal due to damage or the like can be reduced, so that the running cost can be reduced.

In the present embodiment, in particular, the wavelength 0.9
The same Nd: YAG laser 10 is used for a neodymium-doped solid-state laser that oscillates laser light in the μm band and a neodymium-doped solid-state laser that oscillates laser light in the 1.0 μm band.
1 is also used, and this makes it easy to oscillate two laser beams simultaneously. On the other hand, when the first and second neodymium-doped solid-state lasers are different, it is necessary to synchronize them.

It should be noted that another oscillator can be used for a neodymium-doped solid-state laser that oscillates laser light in a wavelength band of 1.0 μm.
As described above, the output wavelength can be adjusted by finely adjusting the wavelength in the μm band.

(Embodiment 5) FIG. 9 is a configuration diagram showing a seed light oscillator used as an exposure light source according to Embodiment 5. The seed light oscillator of the present embodiment is a multi-mode seed light oscillator 200 that generates multi-mode seed light.

In the multimode seed optical oscillator 200, four oscillators similar to the seed optical oscillator 3 of the fourth embodiment shown in FIG. 8 are used. In FIG. 9, the seed optical oscillators 201a, 201b, and 201b are respectively used. Reference numerals 201c and 201d are used. Seed light oscillator 201a, 201b, 201
The seed lights L81a, L81b, L81c, and L81d having a wavelength of 193 nm extracted from c and 201d are respectively triangular mirrors 202a, 202b, 202c, and 202d.
Incident on. Seed light L81a, L8 that emitted these
1b, L81c and L81d are L81a 'and L81 in the figure.
b ', L81c', and L81d ', so that they are almost in close contact with each other.
injected into the rF amplifier.

In the present embodiment, since the seed light L82 is composed of four seed lights having different phases from each other, the combined seed light has low coherence. Therefore, when the light is passed through an ArF excimer laser, laser light having low coherence is extracted.

The four seed beams L81 shown in FIG.
a, L81b, L81c, and L81d are converted to a triangular mirror 202.
a, 202b, 202c, 202d
Each seed light L81a, L81b, L81c, L81d has some loss. That is, the unified seed light L8
Although the power of 2 slightly decreases, it is not used for exposure as it is and is injected into an ArF excimer laser, so that the power of exposure light does not decrease. That is, as shown in FIG. 11, in the injection-locked ArF excimer laser, if the power of the seed light is a certain level or more,
This is because the laser output obtained from the ArF excimer laser has almost the same characteristics.

In addition, the triangular mirror 2 hit by four beams
Since low power seed beams L81a, L81b, L81c, and L81d impinge on 02a, 202b, 202c, and 202d, these triangular mirrors 202a, 202
It is a feature of the present invention that b, 202c and 202d are hardly deteriorated.

In this case, the light-transmitting members of Embodiments 1 to 3 are not necessary, but the light-transmitting members may be passed to further reduce coherence.

(Embodiment 6) FIG. 10 is a sectional view showing a method of manufacturing a semiconductor device according to an embodiment of the present invention in the order of steps.

The manufacturing method of this embodiment is the same as that of the first embodiment.
This is performed using the exposure light sources of Nos. 1 to 5. Hereinafter, a case will be described in which a semiconductor device is manufactured using the exposure machine 2 (for example, the exposure machine shown in FIG. 8) of the first embodiment shown in FIG.

In FIG. 10, as an example of a step of performing processing by photolithography, silicon dioxide (Si) deposited (deposited) on the surface of a silicon substrate 1001 is shown.
The case where a minute hole (contact hole) is formed in the film 1002 of O ₂ ) is illustrated.

In the photolithography process, first, as shown in (1), a resist 1003 is applied to a SiO ₂ film 1002 deposited on a silicon substrate 1001. Next, as shown in (2), exposure light (shown by a number of arrows) is applied to the resist 100 on the surface of the substrate 1001.
Exposure is performed by irradiating No.3. In other words, the resist 1003 is irradiated with exposure light having a predetermined pattern whose irradiation distribution in a plane perpendicular to the optical axis becomes a predetermined pattern by passing through the reticle. Here, the region corresponding to the hole having the diameter ΔW is not irradiated with the exposure light.

In this embodiment, the resist 1003
Is a negative resist, and when developed after exposure, only the hole of diameter ΔW where the exposure light is not irradiated is dissolved in the developer and removed as shown in (3),
An opening 1003a is formed.

Then, as shown in (4), when etching is performed, the thin film 1002 exposed from the opening 1003a of the resist 1003 is removed by etching.

Finally, as shown in (5), by removing the resist 1003 by ashing or the like, the diameter ΔW
SiO ₂ film 10 having a contact hole 1002a
02 will remain on the substrate 1001.

In this embodiment, the wavelength of the exposure light is 193.
nm, a hole (contact hole, etc.) with a minimum diameter of about 0.19 μm or
A line with a width of 0.19 μm can be processed. Further, in the exposure apparatus of the present embodiment, the annular illumination can be configured without lowering the illuminance.
Holes and lines with a diameter of 12 μm can be machined with high throughput.

[0102] Although described the case of forming a contact hole in this embodiment, SiO ₂ film 100
2 can be replaced with a polycrystalline silicon film and the gate electrode of the MISFET can be naturally patterned. In this case, the line width and space of the gate electrode can be processed to a fine size comparable to the above-mentioned size. Also, S
Replacing the iO ₂ film 1002 with a metal film, the DRAM (Dyna
It can also be applied to patterning of a storage capacitor element (lower electrode) of a mic random access memory. In addition, it goes without saying that the present invention can be applied to processing of a member requiring fine patterning.

Although the invention made by the inventor has been specifically described based on the embodiments of the present invention, the present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the scope of the invention. Needless to say, it can be changed.

[0104]

The effects obtained by typical ones of the inventions disclosed in the present application will be briefly described as follows.

That is, in the semiconductor manufacturing apparatus of the present invention,
Since the above-mentioned exposure light source is used and the above-mentioned exposure light source has the above-described configuration, the phases of the exposure light are different in the beam cross section. For this reason, speckle noise is reduced even with one pulse. Thereby, particularly when applied to a scanning type exposure apparatus, the minimum number of pulses can be reduced, thereby increasing the throughput.

In the semiconductor manufacturing apparatus of the present invention, a light source based on wavelength conversion is used.
It only needs times. Furthermore, since OPO is not used, high-output seed light can be generated. Further, the wavelength can be stabilized. Further, if injection locking is configured as the exposure light source, the output obtained from the ArF excimer laser can be sufficiently increased.

Further, since it is easy to increase the output of the light source by wavelength conversion, it can be used not only as a seed light but also as an exposure light source as it is.
In that case, an ArF excimer laser is not required, so that there is an effect that gas exchange is not required.

In addition, the reliability of the system is improved. That is, if the number of wavelength conversions is large, the frequency of stopping the apparatus to replace the crystal due to damage or the like increases, but in the present invention, the number of wavelength conversions is small, and the frequency of replacing optical components is reduced to improve the operation rate. it can.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating an example of an exposure machine according to a first embodiment of the present invention.

FIG. 2 is a top view of a resonator configuration showing a comparative example studied by the inventor of the present invention.

FIG. 3 is a conceptual perspective view showing a resonator configuration according to the first embodiment of the present invention.

FIG. 4 is a perspective view showing a scan type exposure apparatus according to the first embodiment of the present invention.

FIG. 5 is a perspective view showing another example of the transparent member used in Embodiment 2 of the present invention.

FIG. 6 is a perspective view showing another example of a transparent member used in Embodiment 3 of the present invention.

FIG. 7 is a conceptual diagram showing a seed light generation method according to a fourth embodiment of the present invention.

FIG. 8 is a configuration diagram illustrating a seed light generating unit according to a fourth embodiment of the present invention.

FIG. 9 is a configuration diagram illustrating a seed light oscillator used in an exposure light source according to a fifth embodiment of the present invention.

FIG. 10 is a sectional view illustrating a method of manufacturing a semiconductor device according to an embodiment of the present invention in the order of steps;

FIG. 11 is a graph showing a change in ArF excimer laser output according to seed light power.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Exposure light source 2 Exposure machine main body 3 Seed light oscillator 4 ArF excimer laser 5 Beam width expander 6a, 6b Mirror 7, 20, 30 Transmissive member 8 Concave mirror with hole 9 Convex mirror 10 Discharge tube 11a, 11b Window 12a, 12b Plane mirror 30a Triangular plate 30b Parts other than triangular plate 31 Rotation axis 41 Illumination system 42 Reticle scan stage 43 Reticle 44 Projection lens 45 Wafer scan stage 46 Wafer 47 Mirror 48 Optical system 101 Nd: YAG laser 102 Nd: YAG crystal 103 Total reflection mirror 104 Output mirror 105 Q switches 106a, 106b, 106c Dichroic mirrors 107a, 107b Mirrors 108a, 108b, 108c, 108d, 108e,
108f Lens 109a, 109b, 109c Non-linear optical crystal 110 Absorbing plate 200 Multi-mode seed light oscillator 201a, 201b, 201c, 201d Seed light oscillator L1, L2, L3, L4, L8 Seed light L5, L9 Laser beam L10 with wavelength of 193 nm L10 Wavelength Laser light including 1064 nm and 946 nm L11 Laser light having a wavelength of 946 nm L12, L12 Laser light having a wavelength of 1064 nm L13 Laser light having a wavelength of 473 nm (including residual fundamental wave) L13 'Laser light having a wavelength of 473 nm L14 Laser light having a wavelength of 946 nm (Residual fundamental wave) L15, L15 'Laser light having a wavelength of 236.5 nm L16 Laser light obtained by combining 236.5 nm and 1064 nm L17, L17' Laser light (seed light) having a wavelength of 193.5 nm L81a, L81b, 81c, L81d, L81
a ', L81b', L81c ', L81d', L82
Seed light 1001 Substrate 1002 SiO ₂ film 1002a Contact hole 1003 Resist 1003a Opening

Claims (9)

[Claims] 1. A laser light generating means using wavelength conversion,
A semiconductor manufacturing apparatus having an injection-locked ArF excimer laser using light generated by said laser light generating means as seed light, wherein a light transmitting path is provided between said laser light generating means and said ArF excimer laser. A member is disposed, and the seed light in the translucent member has a different passing distance in a beam plane. 2. A laser light generating means using wavelength conversion,
A semiconductor manufacturing apparatus having an injection-locked ArF excimer laser using light generated by said laser light generating means as seed light, wherein a light transmitting path is provided between said laser light generating means and said ArF excimer laser. A semiconductor manufacturing apparatus, wherein a member is arranged, and a phase of the seed light at an exit end face of the light transmitting member is different in a beam plane of the seed light. 3. The semiconductor manufacturing apparatus according to claim 1, wherein the translucent member includes a plurality of translucent member pieces having different dimensions in the optical path direction arranged one-dimensionally or two-dimensionally. A semiconductor manufacturing apparatus characterized in that: 4. The semiconductor manufacturing apparatus according to claim 1, wherein the light-transmissive member is formed by circumferentially disposing light-transmissive member pieces having different dimensions in the optical path direction. A semiconductor manufacturing apparatus, wherein the translucent member is rotatable around the center of the circumference. 5. A laser light generating means using wavelength conversion,
A semiconductor manufacturing apparatus comprising: an injection-locked ArF excimer laser using light generated by the laser light generating means as seed light, wherein the seed light includes a plurality of beams. 6. The semiconductor manufacturing apparatus according to claim 1, wherein the seed light has a rectangular cross-sectional shape, and a resonator of the ArF excimer laser includes a plurality of plane mirrors. A semiconductor manufacturing apparatus characterized by being performed. 7. A semiconductor manufacturing apparatus comprising: a laser light generating means; and an injection-locked ArF excimer laser using light generated by the laser light generating means as seed light, wherein the laser light generating means includes: A first and second neodymium-doped solid-state lasers, wherein the seed light includes a fourth harmonic of a 0.9 μm band fundamental wave of the first neodymium-doped solid-state laser and one of the second neodymium-doped solid-state lasers. .0
A semiconductor manufacturing apparatus having a sum frequency with a μm band fundamental wave. 8. The semiconductor manufacturing apparatus according to claim 7, wherein said first neodymium-doped solid-state laser is Nd: YAG.
And the second neodymium-doped solid-state laser is an Nd: YAG laser, an Nd: GSGG laser,
d: an LMA laser or an Nd: CaWO ₄ laser. 9. A step of forming a photoresist film having a sensitivity in a 0.19 μm band;
Exposing with an injection-locked ArF excimer laser beam using a laser beam generated using wavelength conversion as a seed beam, wherein the seed beam is injected into the ArF excimer laser. In this case, the first configuration in which the phase is different in the beam cross section, and the seed light is 0.1 mm in the first neodymium-doped solid-state laser.
The second harmonic, which is the sum frequency of the fourth harmonic of the 9 μm band fundamental wave and the 1.0 μm band fundamental wave of the second neodymium-doped solid-state laser.
The manufacturing method of the semiconductor device characterized by any one of the above configurations.