Laser system and method for manufacturing electronic device

Abstract

The invention provides a laser system and a method for manufacturing an electronic device. The laser system includes: a laser oscillator; a lens array including a first lens to which a first portion of the laser beam output from the laser oscillator is incident, and a second lens to which a second portion of the laser beam different from the first portion is incident, the second portion having a spatial coherence length smaller than a spatial coherence length of the first portion, the distance between the second lenses is smaller than that between the first lenses; and a condenser lens that overlaps the first portion and the second portion that have passed through the lens array on a common irradiation surface.

Description

Technical Field

[0001] This disclosure relates to methods for manufacturing laser systems and electronic devices. Background Technology

[0002] In recent years, with the miniaturization and high integration of semiconductor integrated circuits, there has been a growing demand for higher resolution in semiconductor exposure equipment. Therefore, efforts are underway to shorten the wavelength of light emitted from exposure light sources. For example, KrF excimer laser devices using lasers with an output wavelength of approximately 248 nm and ArF excimer laser devices using lasers with an output wavelength of approximately 193 nm are examples of gas laser devices used for exposure.

[0003] The natural oscillating light from KrF and ArF excimer lasers has a wide spectral linewidth, ranging from 350 pm to 400 pm. Therefore, if the projection lens is made of a material that allows ultraviolet light, such as that of KrF and ArF lasers, to pass through, chromatic aberration may occur. As a result, resolution may be reduced. Therefore, it is necessary to narrow the spectral linewidth of the laser output from the gas laser device to a level where chromatic aberration is negligible. Thus, in order to narrow the spectral linewidth, gas laser devices sometimes include a line-narrowing module (LNM) containing narrowing elements (etalon, grating, etc.). Gas laser devices with narrowed spectral linewidths are called narrow-band gas laser devices.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: U.S. Patent Application Publication No. 2006 / 109443

[0007] Patent Document 2: Japanese Patent Application Publication No. 2004-093837 Summary of the Invention

[0008] A laser system according to one aspect of this disclosure comprises: a laser oscillator; a lens array including a first lens and a second lens, wherein a first portion of a laser beam output from the laser oscillator is incident on the first lens, and a second portion of the laser beam, different from the first portion, is incident on the second lens, the spatial coherence length of the second portion being smaller than that of the first portion, and the spacing between the second lenses being smaller than that between the first lenses; and a focusing lens that causes the first portion and the second portion passing through the lens array to coincide on a common illumination surface.

[0009] One aspect of the disclosed method for manufacturing an electronic device includes the following steps: generating a laser beam using a laser system, outputting the laser beam to an exposure apparatus, and exposing the laser beam on a photosensitive substrate within the exposure apparatus to manufacture the electronic device. The laser system comprises: a laser oscillator; a lens array including a first lens and a second lens, wherein a first portion of the laser beam output from the laser oscillator is incident on the first lens, and a second portion of the laser beam, different from the first portion, is incident on the second lens, the spatial coherence length of the second portion being smaller than that of the first portion, and the spacing between the second lenses being smaller than that between the first lenses; and a focusing lens that causes the first and second portions passing through the lens array to coincide on a common illumination surface. Attached Figure Description

[0010] The following description, by way of example only, refers to the accompanying drawings to illustrate several embodiments of this disclosure.

[0011] Figure 1 The structure of the laser system in the comparative example is shown.

[0012] Figure 2 An example representing the light quantity distribution in the beam cross section of a laser beam incident on a homogenizer.

[0013] Figure 3 This indicates the structure of the homogenizer in the comparative example.

[0014] Figure 4 This shows the structure of another homogenizer in the comparative example.

[0015] Figure 5 This represents the spatial coherence length of each part of the laser beam's cross-section and the spacing between the lenses.

[0016] Figure 6 An example of a method for measuring the spatial coherence length of different parts of a laser beam.

[0017] Figure 7 An example of the measurement results showing the contrast of each pinhole interval.

[0018] Figure 8 This indicates the structure of the homogenizer in the first embodiment.

[0019] Figure 9 This is a diagram used to illustrate the definition of spacing.

[0020] Figure 10 This represents a first example of the lens spacing in the first embodiment.

[0021] Figure 11 This is a second example illustrating the spacing between the lenses in the first embodiment.

[0022] Figure 12This is a third example illustrating the spacing between the lenses in the first embodiment.

[0023] Figure 13 The structure of the homogenizer in a variation of the first embodiment is shown.

[0024] Figure 14 Examples illustrating the lens spacing in a variation of the first embodiment.

[0025] Figure 15 This represents the two-dimensional light distribution on the irradiated surface in the comparative example.

[0026] Figure 16 Indicates will Figure 15 The light distribution shown is obtained by integrating each Y coordinate in the X direction.

[0027] Figure 17 This represents the two-dimensional light distribution of the irradiated surface in the first embodiment.

[0028] Figure 18 Indicates will Figure 17 The light distribution shown is obtained by integrating each Y coordinate in the X direction.

[0029] Figure 19 This indicates the structure of the homogenizer in the second embodiment.

[0030] Figure 20 The structure of the homogenizer in a variation of the second embodiment is shown.

[0031] Figure 21 This indicates the structure of the homogenizer in the third embodiment.

[0032] Figure 22 This shows the structure of the laser system in the fourth embodiment.

[0033] Figure 23 This shows the detailed structure of the laser system.

[0034] Figure 24 This indicates the structure of the exposure system. Detailed Implementation

[0035] <Content>

[0036] 1. Comparative Example

[0037] 1.1 Laser System 100a

[0038] 1.2 Homogenizer 1a

[0039] 2. The topic of comparative examples

[0040] 3. Method for determining spatial coherence length Xc

[0041] 4. Lens array 10c with spacing P varying according to spatial coherence length Xc.

[0042] 4.1 Overview

[0043] 4.2 Definition of Spacing P

[0044] 4.3 Lens spacing P from 11c to 17c

[0045] 4.3.1 First example

[0046] 4.3.2 Second Case

[0047] 4.3.3 Third Case

[0048] 4.4 Focal length of the lens from 11c to 17c

[0049] 4.5 Lens array 10d including light-shielding part M

[0050] 4.6 Function

[0051] 5. A lens array 10e in which the principal surfaces of lenses 11e to 17e are staggered.

[0052] 5.1 Principal planes of lenses 11e to 17e

[0053] 5.2 Lens array 10f including light-shielding part M

[0054] 5.3 Function

[0055] 6. A lens array comprising a first cylindrical lens (10g) and a second cylindrical lens (20g).

[0056] 6.1 Structure

[0057] 6.2 Function

[0058] 7. The homogenizer 1c located inside the laser amplifier PO is the irradiation surface 5.

[0059] 7.1 Structure

[0060] 7.2 Actions

[0061] 7.2.1 Operation of the Laser Oscillator (MO)

[0062] 7.2.2 Operation of Laser Amplifier PO

[0063] 7.2.3 Operation of the Optical Pulse Stretcher 99

[0064] 7.3 Function

[0065] 8. Other

[0066] 8.1 Manufacturing methods for electronic devices

[0067] 8.2 Supplement

[0068] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The embodiments described below represent several examples of the present disclosure and do not limit the content of the present disclosure. In addition, the structures and operations described in each embodiment are not necessarily all necessary as structures and operations of the present disclosure. Furthermore, the same reference numerals are used to denote the same constituent elements, and repeated descriptions are omitted.

[0069] 1. Comparative Example

[0070] 1.1 Laser System 100a

[0071] Figure 1 The comparative example illustrates the structure of the laser system 100a in the comparative example. The comparative examples disclosed herein are those known only to the applicant and are not publicly known examples endorsed by the applicant.

[0072] The laser system 100a includes a laser oscillator MO and a homogenizer 1a. The laser oscillator MO is, for example, a discharge-excited gas laser device such as an excimer laser, configured to output a laser beam B. Regarding the structure of the homogenizer 1a, refer to... Figure 3 As will be described later. The laser beam B irradiates the irradiation surface 5 through the homogenizer 1a. The irradiation surface 5 is, for example, the processing surface of the workpiece in an apparatus that uses the laser beam B for processing.

[0073] Figure 2 This illustrates an example of the light quantity distribution in the beam cross-section of a laser beam B incident on homogenizer 1a. The shape of the beam cross-section of the laser beam B is, for example, approximately rectangular, but due to factors such as the distribution of the laser gas in the laser oscillator MO and deviations in the discharge of the excitation laser gas, it sometimes exhibits a non-uniform light quantity distribution. Homogenizer 1a emits the laser beam B in a manner that homogenizes the light quantity distribution in the beam cross-section of the laser beam B on the irradiation surface 5.

[0074] 1.2 Homogenizer 1a

[0075] Figure 3 The structure of the homogenizer 1a in the comparative example is shown. The homogenizer 1a includes a lens array 10a and a condenser lens 30a. The lens array 10a includes lenses 11a to 14a disposed at the beam cross-section of the laser beam B. Lenses 11a to 14a are, for example, convex lenses. Figure 3 In the figure, the leader lines of the reference numerals corresponding to lenses 11a to 14a and condenser lens 30a indicate the positions of the principal surfaces of these lenses.

[0076] The laser beam B includes a portion B1 incident on lens 11a, a portion B2 incident on lens 12a, a portion B3 incident on lens 13a, and a portion B4 incident on lens 14a.

[0077] Parts B1 to B4 are affected by lens array 10a, resulting in changes in their expansion angles. Figure 3 In the process, portions of B1 to B4 are given negative expansion angles and emitted, then temporarily focused, becoming beams with positive expansion angles that enter the condenser lens 30a. Figure 3 In the diagram, dashed lines represent the optical path axes and outer edges of parts B1 to B4, respectively.

[0078] The focusing lens 30a causes portions B1 to B4 that have passed through the lens array 10a to coincide on a common illumination surface 5. Figure 3 This indicates that the optical paths of portions B1 to B4 are aligned with the central portion of the irradiation surface 5, and that the optical paths of portions B1 to B4 are aligned with the central portion of the irradiation surface 5. Figure 3 The upper and middle rays overlap the upper part of the irradiated surface 5, causing portions B1 to B4 to be illuminated by the light. Figure 3 The lower and middle portions of the light beam overlap with the lower part of the irradiated surface 5. By making the different parts of the laser beam B overlap, the light distribution becomes more uniform.

[0079] 2. The topic of comparative examples

[0080] Figure 4 This shows the structure of another homogenizer 1b in the comparative example. Homogenizer 1b can also be used instead. Figure 1 The homogenizer 1a is shown. The homogenizer 1b differs from homogenizer 1a in that the number of lenses 11b to 18b constituting lens array 10b is greater than the number of lenses 11a to 14a constituting lens array 10a. The spacing P of each of lenses 11b to 18b is smaller than the spacing of each of lenses 11a to 14a. Furthermore, in... Figure 4 The dashed lines representing the optical path axes B1 to B8 that pass through lenses 11b to 18b are omitted. In other respects, the lens array 10b, each lens 11b, 12b, etc., constituting the homogenizer 1b, and the condenser lens 30b are substantially the same as the corresponding structures of the homogenizer 1a.

[0081] In geometric optics, the smaller the distance P between lenses 11b to 18b, the more the laser beam B is divided into multiple parts, and the more these parts overlap on the illumination surface 5, thus resulting in a higher level of uniformity in light distribution. However, when the distance P is less than the spatial coherence length Xc of the laser beam B, the diffracted beams at the ends of lenses 11b to 18b overlap, producing interference fringes on the illumination surface 5, which may lead to insufficient uniformity in light distribution.

[0082] Figure 5 Let Xc represent the spatial coherence length of each part of the beam cross section of laser beam B and the lens spacing P. Figure 5 The horizontal axis represents Figure 4 The position in the Y direction, Figure 5 The vertical axis represents the spatial coherence length Xc and the spacing P. The spacing P is equivalent to the width of the lens in the Y direction, therefore Figure 5 The quadrilaterals shown are all squares, and the length of one side of each square represents the distance P between the lenses. For example... Figure 5 As shown, the spatial coherence length Xc is not uniform across the beam cross-section of the laser beam B. For example, sometimes the spatial coherence length Xc is larger in the central part of the laser beam B and smaller in the peripheral part. In contrast, the distance P between lenses 11b to 18b in the comparative example is equal to each other.

[0083] In this case, since the distance P in lenses 12b and 17b is approximately equal to the spatial coherence length Xc, the effect of improving the uniformity of light distribution can be sufficiently obtained, and the generation of interference fringes can also be suppressed. However, in lenses 11b and 18b at the ends of lens array 10b, since the distance P is larger than the spatial coherence length Xc, there is room to improve the uniformity of light distribution if the distance P is further reduced, but the effect cannot be fully obtained. On the other hand, in lenses 13b to 16b near the center of lens array 10b, since the distance P is smaller than the spatial coherence length Xc, interference fringes may be generated.

[0084] Therefore, in the comparative example, the following problem exists: even if the spacing P is adjusted, the effect of improving the uniformity of the light distribution cannot be fully obtained in a part of the laser beam B, or interference fringes are generated in another part.

[0085] The implementation described below does not make the spacing P of the multiple lenses contained in the lens array equal to each other, but is set to a spacing P corresponding to the spatial coherence length Xc, which is associated with improving the uniformity of light distribution and suppressing the generation of interference fringes.

[0086] 3. Method for determining spatial coherence length Xc

[0087] Figure 6 This example illustrates a method for measuring the spatial coherence length Xc of different portions of a laser beam B. In this example, light diffracted by the double pinholes formed on the mask 61 is observed on a screen 62 sufficiently far from the mask 61, and the visibility of the interference fringe FR is measured as the contrast V. As the pinhole spacing d is gradually increased from 0 at different portions of the laser beam B in the Y direction, the contrast V of the interference fringe FR formed on the screen 62 gradually decreases.

[0088] Figure 7This is an example of the measurement result of the contrast V for each pinhole spacing d. The pinhole spacing d that can be measured when the contrast V is below a threshold Vth is taken as the spatial coherence length Xc of that portion. The threshold Vth is set to a value such that if it is below which the interference is sufficiently low and can be judged to be greater than the measurement noise of the contrast V, for example, a value of 3% or more and 5% or less. For example, according to... Figure 7 The obtained spatial coherence length Xc is approximately 1.3 mm.

[0089] The spatial coherence length Xc can be measured not only at different parts of the laser beam B in the Y direction, but also at different parts in the X direction.

[0090] 4. Lens array 10c with spacing P varying according to spatial coherence length Xc.

[0091] 4.1 Overview

[0092] Figure 8 This illustrates the structure of the homogenizer 1c in the first embodiment. Alternatively, homogenizer 1c can be used instead. Figure 1 The homogenizer 1a is shown. The homogenizer 1c differs from homogenizers 1a and 1b in that the spacing P of the lenses 11c to 17c that constitute the lens array 10c is not uniform.

[0093] 4.2 Definition of Spacing P

[0094] Figure 9 This diagram illustrates the definition of the spacing P. In this disclosure, the distance between the centerlines of adjacent lenses is defined as the spacing P. For example, suppose the lens array includes lenses 11 to 13. The distance between the centerline CL1 between the centers of adjacent lenses 11 and 12 and the centerline CL2 between the centers of adjacent lenses 12 and 13 is called the spacing P2 of lens 12. That is, when half of the distance C1 between the centers of adjacent lenses 11 and 12 is defined as L1, and half of the distance C2 between the centers of adjacent lenses 12 and 13 is defined as L2, the sum of L1 and L2 is called the spacing P2 of lens 12.

[0095] Regarding the spacing P of lenses 11 and 13 at the ends of the lens array, twice the distance between the center of the lens and the center of its adjacent lens is defined as spacing P. For example, twice the distance L1 between the center of lens 11 and the centerline CL1 between the centers of lenses 11 and 12 is called the spacing P1 of lens 11. Twice the distance L2 between the center of lens 13 and the centerline CL2 between the centers of lenses 13 and 12 is called the spacing P3 of lens 13.

[0096] These spacings P1 to P3 may not necessarily coincide with the center-to-center distance C1 of adjacent lenses 11 and 12, or the center-to-center distance C2 of adjacent lenses 12 and 13. Furthermore, spacings P1 to P3 are sizes greater than or equal to the aperture dimensions D1 to D3 of lenses 11 to 13. Figure 8 In the middle, the distance P between lenses 11c to 17c is approximately equal to the opening size of lenses 11c to 17c.

[0097] 4.3 Lens spacing P from 11c to 17c

[0098] Figures 10-12 The first to third examples represent the distance P between lenses 11c to 17c in the first embodiment. Figures 10-12 Nakaya and Figure 5 Similarly, Xc represents the spatial coherence length at various points along the beam cross-section of laser beam B. Figures 10-12 The quadrilaterals shown are squares, and the length of one side of each square represents the distance P between the lenses.

[0099] As in the first to third examples described below, it is preferable to increase the spacing P of the lenses that incident on the portion of the laser beam B with a large spatial coherence length Xc, and decrease the spacing P of the lenses that incident on the portion with a small spatial coherence length Xc. For example, compared to lens 14c that incident on portion B4 of the laser beam B, the spacing P of lens 15c that incident on portion B5, whose spatial coherence length Xc is smaller than that of portion B4, is decreased. Furthermore, the spacing P of lens 16c that incident on portion B6, whose spatial coherence length Xc is smaller than that of portion B5, is made smaller than the spacing P of lens 15c that incident on portion B5.

[0100] Here, we illustrate a case where the spatial coherence length Xc is larger in the central portion of laser beam B and smaller in the peripheral portion. For example, the portion B4 with a larger spatial coherence length Xc is closer to the center C of the beam cross-section of laser beam B (refer to...). Figure 8 The distance between the portions of B5 and B4 is shorter than the distance between the portion B5 and the center C of the beam cross section, and the spatial coherence length Xc of the portion B5 is smaller than the spatial coherence length Xc of the portion B4. In this case, the spacing P of the lenses 15c located at a position far from the center of the lens array 10c is reduced compared to the lens 14c located at the center of the lens array 10c. However, this disclosure is not limited to this, and it is also possible that the spatial coherence length Xc of the central portion of the laser beam B is smaller, and the spatial coherence length Xc of the peripheral portion is larger.

[0101] 4.3.1 First example

[0102] exist Figure 10In the first example shown, the spacing P between the lenses is the maximum value of the spatial coherence length Xc of the portion of the laser beam B incident on that lens. For example, the spacing P of lenses 14c is the maximum value Xc4max of the spatial coherence length Xc of the portion B4 incident on lens 14c. The spacing P of lenses 15c is the maximum value Xc5max of the spatial coherence length Xc of the portion B5 incident on lens 15c.

[0103] The distance P between the lenses can be greater than the maximum value of the spatial coherence length Xc of the portion of the laser beam B incident on the lens.

[0104] 4.3.2 Second Case

[0105] exist Figure 11 In the second example shown, the distance P between the lenses is greater than the minimum spatial coherence length Xc of the portion of the laser beam B incident on that lens. Furthermore, the distance P between the lenses is less than the maximum spatial coherence length Xc of the portion of the laser beam B incident on that lens. For example, the distance P between lenses 14c is greater than the minimum spatial coherence length Xc4min of the portion B4 incident on lens 14c, but smaller than the maximum value Xc4max. The distance P between lenses 15c is greater than the minimum spatial coherence length Xc5min of the portion B5 incident on lens 15c, but smaller than the maximum value Xc5max. The distance P between lenses 16c is greater than the minimum spatial coherence length Xc6min of the portion B6 incident on lens 16c, but smaller than the maximum value Xc6max.

[0106] 4.3.3 Third Case

[0107] exist Figure 12 In the third example shown, the spacing P of each lens is the average value of the spatial coherence length Xc of the portion of the laser beam B incident on that lens. For example, the spacing P of lens 14c is the average value Xc4avg of the spatial coherence length Xc of the portion B4 incident on lens 14c. The spacing P of lens 15c is the average value Xc5avg of the spatial coherence length Xc of the portion B5 incident on lens 15c. The spacing P of lens 16c is the average value Xc6avg of the spatial coherence length Xc of the portion B6 incident on lens 16c.

[0108] The distance P between the lenses can be greater than the average value of the spatial coherence length Xc of the portion of the laser beam B incident on the lens.

[0109] 4.4 Focal length of the lens from 11c to 17c

[0110] Refer again Figure 8The smaller the distance P between lenses 11c to 17c, the smaller the aperture size. For example, the aperture size of lens 15c is smaller than that of lens 14c. The parameters and configuration of lenses 11c to 17c are set as follows, so that the size difference between portions B1 to B7 passing through lenses 11c to 17c on the illumination surface 5 is reduced, preferably making the sizes of portions B1 to B7 on the illumination surface 5 equal to each other.

[0111] The smaller the aperture size of lenses 11c to 17c, the longer the focal length. That is, among the portions B1 to B7 that pass through lenses 11c to 17c, the portion that passes through the smaller aperture size of the lens, the longer the distance between the principal surface of lenses 11c to 17c and the focusing positions R1 to R7. For example, the second distance between the principal surface of lens 15c and the focusing position R5 of the portion B5 that passes through lens 15c is longer than the first distance between the principal surface of lens 14c and the focusing position R4 of the portion B4 that passes through lens 14c.

[0112] Preferably, the difference between the third and fourth distances is smaller than the difference between the first and second distances. The third distance is the distance between the main surface of lens 14c and the main surface of condenser lens 30c; the fourth distance is the distance between the main surface of lens 15c and the main surface of condenser lens 30c; the first distance is the distance between the main surface of lens 14c and the focusing position R4; and the second distance is the distance between the main surface of lens 15c and the focusing position R5. Figure 8 In the middle, the principal surfaces of lenses 11c to 17c are equidistant from the principal surface of condenser lens 30c.

[0113] Furthermore, in portions B1 to B7, the closer the aperture size of the lens is to the portion through which the light passes, the shorter the distance between the focusing positions R1 to R7 and the main surface of the focusing lens 30c. For example, the sixth distance between the focusing position R5 of portion B5, which passes through lens 15c, and the main surface of the focusing lens 30c is shorter than the fifth distance between the focusing position R4 of portion B4, which passes through lens 14c, and the main surface of the focusing lens 30c.

[0114] Lens 14c corresponds to the first lens in this disclosure, lens 15c corresponds to the second lens in this disclosure, and lens 16c corresponds to the third lens in this disclosure. Part B4 corresponds to the first part in this disclosure, part B5 corresponds to the second part in this disclosure, and part B6 corresponds to the third part in this disclosure. Focusing position R4 corresponds to the first focusing position in this disclosure, and focusing position R5 corresponds to the second focusing position in this disclosure.

[0115] 4.5 Lens array 10d including light-shielding part M

[0116] Figure 13 This illustrates the structure of the homogenizer 1d in a variation of the first embodiment. Homogenizer 1d can also be used instead. Figure 1 The homogenizer 1a is shown. The difference between homogenizer 1d and homogenizer 1c is that a light-shielding portion M is arranged between adjacent lenses 11d to 17d constituting the lens array 10d. In this case, the opening size of lenses 11d to 17d is smaller than their respective spacing P. For example, if the planar shape of each of lenses 11d to 17d is circular, it is impossible to fill the entire surface of the lens array 10d with lenses; therefore, a light-shielding portion M can also be arranged between the lenses.

[0117] exist Figure 13 Similar to homogenizer 1c, an example is shown where a smaller spacing P results in a smaller aperture size for lenses 11d to 17d, but this disclosure is not limited to this. Alternatively, the aperture sizes of lenses 11d to 17d can be made equal by making the light-shielding portion M near the center of lens array 10d larger than the light-shielding portion M near the periphery of lens array 10d.

[0118] Figure 14 This refers to an example showing the distance P between lenses 11d to 17d in a variation of the first embodiment. Except for the reference numerals for lenses 11d to 17d, Figure 14 and Figure 10 The same. Alternatively, it can also be the same as in a variation of the first embodiment. Figure 11 or Figure 12 Similarly, the distance P between lenses 11d and 17d is determined.

[0119] In other respects, homogenizer 1d is the same as homogenizer 1c.

[0120] 4.6 Function

[0121] (1) According to the first embodiment, the laser system 100a includes a laser oscillator MO, a lens array 10c, and a focusing lens 30c. The lens array 10c includes: a lens 14c, into which a portion B4 of the laser beam B output from the laser oscillator MO is incident; and a lens 15c, into which a portion B5 of the laser beam B, different from the portion B4, is incident, wherein the spatial coherence length Xc of the portion B5 is smaller than the spatial coherence length of the portion B4, and the spacing P of the lenses 15c is smaller than the spacing of the lenses 14c. The focusing lens 30c causes the portions B4 and B5 that have passed through the lens array 10c to coincide on a common illumination surface 5.

[0122] Therefore, the spacing P of lens 15c, which receives light from the portion B4 with a larger spatial coherence length Xc, is smaller than that of lens 14c. This mitigates the problem that when the spacing P of lenses 14c and 15c is set to the value most suitable for portion B4, the homogenization effect on the light distribution of portion B5 is insufficient, or that interference fringes caused by portion B4 occur when the spacing P of lenses 14c and 15c is set to the value most suitable for portion B5. Thus, the uniformity of the light distribution of the laser beam B can be improved, and the generation of interference fringes can be suppressed.

[0123] Figure 15 This represents the two-dimensional light distribution on the irradiated surface 5 in the comparative example. Figure 16 Indicates will Figure 15 The light distribution shown is obtained by integrating each Y coordinate in the X direction. Figure 17 This represents the two-dimensional light distribution of the irradiation surface 5 in the first embodiment. Figure 18 Indicates will Figure 17 The light distribution shown is obtained by integrating each Y-coordinate along the X-direction. Figure 15 and Figure 16 In the case where the spacing P is set too small, the deviation in light quantity caused by interference is large; conversely, in Figure 17 and Figure 18 In this process, interference is suppressed, and the light distribution is homogenized. Additionally, Figure 17 and Figure 18 This does not represent the limit of the uniformity performance of the light quantity distribution of this disclosure.

[0124] (2) According to the first embodiment, the lens array 10c includes a lens 16c. A portion B6 of the laser beam B, which is different from portions B4 and B5, is incident on the lens 16c. The spatial coherence length Xc of this portion B6 is smaller than the spatial coherence length Xc of portion B5, and the spacing P of the lens 16c is smaller than the spacing P of the lens 15c. The focusing lens 30c causes portions B4 to B6 that have passed through the lens array 10c to coincide on a common illumination surface 5.

[0125] Therefore, by setting the spacing of not only lenses 14c and 15c but also lens 16c to a spacing P corresponding to the spatial coherence length Xc, it is possible to improve the uniformity of light distribution and suppress the generation of interference fringes over a large area of ​​the beam cross section.

[0126] (3) According to the first embodiment, the distance between part B4 and the center C of the beam cross section of the laser beam B is shorter than the distance between part B5 and the center C.

[0127] Therefore, when the spatial coherence length Xc is larger in the central part of the beam cross-section than in the peripheral part, it is possible to improve the uniformity of the light distribution and suppress the generation of interference fringes.

[0128] (4) According to the first embodiment, the spacing P of the lens 14c is greater than or equal to the maximum value Xc4max of the spatial coherence length Xc of part B4, and the spacing P of the lens 15c is greater than or equal to the maximum value Xc5max of the spatial coherence length Xc of part B5.

[0129] Therefore, it is possible to suppress the generation of interference fringes more reliably by making the spacing P smaller than the spatial coherence length Xc of the portions B4 and B5 incident on lenses 14c and 15c.

[0130] (5) According to the first embodiment, the spacing P of lens 14c is greater than the minimum value Xc4min of the spatial coherence length Xc of part B4, and the spacing P of lens 15c is greater than the minimum value Xc5min of the spatial coherence length Xc of part B5.

[0131] Therefore, it is possible to suppress the spatial coherence length Xc of the portions B4 and B5 that are much smaller than the incident lenses 14c and 15c, and thus suppress the generation of interference fringes.

[0132] (6) According to the first embodiment, the spacing P of lens 14c is less than the maximum value Xc4max of the spatial coherence length Xc of part B4, and the spacing P of lens 15c is less than the maximum value Xc5max of the spatial coherence length Xc of part B5.

[0133] Therefore, it is possible to suppress the significant increase in the spacing P compared to the spatial coherence length Xc of the portions B4 and B5 incident on lenses 14c and 15c, thereby improving the uniformity of light distribution.

[0134] (7) According to the first embodiment, the spacing P of the lens 14c is greater than or equal to the average value Xc4avg of the spatial coherence length Xc of the portion B4, and the spacing P of the lens 15c is greater than or equal to the average value Xc5avg of the spatial coherence length Xc of the portion B5.

[0135] Therefore, it is possible to suppress the generation of interference fringes by ensuring that the spacing P is smaller than the spatial coherence length Xc of the portions B4 and B5 incident on lenses 14c and 15c.

[0136] (8) According to the first embodiment, the aperture size of lens 15c is smaller than the aperture size of lens 14c.

[0137] Therefore, by making the aperture size of the lens 14c with a larger spacing P larger than the aperture size of the lens 15c with a smaller spacing P, it is possible to suppress the attenuation of the laser beam B in the lens array 10c.

[0138] (9) According to the first embodiment, the second distance is longer than the first distance. The second distance is the distance between the main surface of the lens 15c and the focusing position R5 of the portion B5 that passes through the lens 15c. The first distance is the distance between the main surface of the lens 14c and the focusing position R4 of the portion B4 that passes through the lens 14c.

[0139] Therefore, by extending the second distance from the main surface of the lens 15c with the smaller aperture to the focusing position R5, the portion B5 that has passed through the lens 15c can be focused closer to the condenser lens 30c, increasing the expansion angle of the portion B5 emitted from the condenser lens 30c. Thus, even the portion B5 that has passed through the lens 15c with the smaller aperture can have its size on the illumination surface 5 increased, making it closer to the size of the portion B4 that has passed through the lens 14c with the larger aperture on the illumination surface 5, thereby reducing the size deviation of portions B4 and B5 on the illumination surface 5.

[0140] (10) According to the first embodiment, the difference between the third distance and the fourth distance is smaller than the difference between the first distance and the second distance. The third distance is the distance between the main surface of the lens 14c and the main surface of the condenser lens 30c, and the fourth distance is the distance between the main surface of the lens 15c and the main surface of the condenser lens 30c.

[0141] Therefore, by reducing the difference between the third and fourth distances, the principal surfaces of lenses 14c and 15c can be positioned close to each other. Thus, lens array 10c can be easily manufactured.

[0142] (11) According to the first embodiment, the sixth distance between the focusing position R5 and the main surface of the focusing lens 30c is shorter than the fifth distance between the focusing position R4 and the main surface of the focusing lens 30c.

[0143] Therefore, even if part B5 of the lens 15c with a small opening size passes through, the size on the irradiation surface 5 can be increased, and the deviation of the size of part B4 and B5 on the irradiation surface 5 can be reduced.

[0144] In other respects, the first embodiment is the same as the comparative example.

[0145] 5. A lens array 10e in which the principal surfaces of lenses 11e to 17e are staggered.

[0146] 5.1 Principal planes of lenses 11e to 17e

[0147] Figure 19 This illustrates the structure of the homogenizer 1e in the second embodiment. Alternatively, homogenizer 1e can be used instead. Figure 1The homogenizer 1a is shown. The difference between homogenizer 1e and homogenizer 1c is that the principal surfaces of lenses 11e to 17e constituting lens array 10e are in different positions. Regarding the fact that a smaller spatial coherence length Xc results in a smaller spacing P between lenses 11e to 17e, homogenizer 1e is the same as homogenizer 1c.

[0148] The smaller the distance P between lenses 11e to 17e, the smaller the opening size. The parameters and configuration of lenses 11e to 17e are set as follows, so that the difference in size and the difference in expansion angle of the portions B1 to B7 incident on the irradiation surface 5 are reduced. Preferably, the sizes of the portions B1 to B7 incident on the irradiation surface 5 are equal and the expansion angles are equal.

[0149] The smaller the aperture size of lenses 11e to 17e, the shorter the focal length. That is, among the portions B1 to B7 that pass through lenses 11e to 17e, the smaller the aperture size of the portion passing through, the shorter the distance between the principal surface of lenses 11e to 17e and the focusing positions R1 to R7. For example, the second distance is shorter than the first distance. This second distance is the distance between the principal surface of lens 15e and the focusing position R5 of the portion B5 that passes through lens 15e, and the first distance is the distance between the principal surface of lens 14e and the focusing position R4 of the portion B4 that passes through lens 14e.

[0150] Furthermore, the smaller the aperture size of lenses 11e to 17e, the shorter the distance between the principal surfaces of lenses 11e to 17e and the principal surface of condenser lens 30e. For example, the fourth distance is shorter than the third distance, which is the distance between the principal surface of lens 15e and the principal surface of condenser lens 30e, and the third distance is the distance between the principal surface of lens 14e and the principal surface of condenser lens 30e.

[0151] Preferably, the difference between the fifth and sixth distances is smaller than the difference between the first and second distances. The fifth distance is the distance between the focusing position R4 and the main surface of the focusing lens 30e; the sixth distance is the distance between the focusing position R5 and the main surface of the focusing lens 30e; the first distance is the distance between the main surface of the lens 14e and the focusing position R4; and the second distance is the distance between the main surface of the lens 15e and the focusing position R5. Figure 19 In the middle, the distance between the focusing positions R1 to R7 and the main surface of the focusing lens 30e is equal.

[0152] The focusing positions R1 to R7, which correspond to the rear focal points of lenses 11e to 17e, are preferably located on the front focal plane F of the condenser lens 30e.

[0153] The preferred lenses have a small difference in numerical aperture between 11e and 17e. Figure 19 In this case, the numerical apertures of lenses 11e to 17e are equal.

[0154] Lens 14e corresponds to the first lens in this disclosure, and lens 15e corresponds to the second lens in this disclosure.

[0155] 5.2 Lens array 10f including light-shielding part M

[0156] Figure 20 This illustrates the structure of the homogenizer 1f in a modified example of the second embodiment. The homogenizer 1f can also be used instead. Figure 1 The homogenizer 1a is shown. The homogenizer 1f differs from the homogenizer 1e in that a light-shielding part M is arranged between adjacent lenses among the lenses 11f to 17f that constitute the lens array 10f.

[0157] exist Figure 20 Similar to homogenizer 1e, an example is shown where a smaller spatial coherence length Xc results in a smaller aperture size for lenses 11f to 17f. However, this disclosure is not limited to this, and the aperture sizes of lenses 11f to 17f can also be made equal to each other.

[0158] In other respects, homogenizer 1f is the same as homogenizer 1e.

[0159] 5.3 Function

[0160] (12) According to the second embodiment, the aperture size of lens 15e is smaller than that of lens 14e, and the fourth distance between the main surface of lens 15e and the main surface of condenser lens 30e is shorter than the third distance between the main surface of lens 14e and the main surface of condenser lens 30e.

[0161] Therefore, by making the fourth distance between the main surface of the lens 15e with the smaller aperture and the main surface of the condenser lens 30e shorter than the third distance between the main surface of the lens 14e and the main surface of the condenser lens 30e, the difference in size and the difference in expansion angle between the portions B4 and B5 incident on the irradiation surface 5 can be reduced. Thus, even if the irradiation surface 5 moves parallel to the travel direction of the laser beam B, the reduction in the uniformity of the laser beam B can be suppressed.

[0162] (13) According to the second embodiment, the second distance is shorter than the first distance. The second distance is the distance between the main surface of the lens 15e and the focusing position R5 of the portion B5 passing through the lens 15e, and the first distance is the distance between the main surface of the lens 14e and the focusing position R4 of the portion B4 passing through the lens 14e. In addition, the difference between the fifth distance and the sixth distance is smaller than the difference between the first distance and the second distance. The fifth distance is the distance between the focusing position R4 and the main surface of the condensing lens 30e, and the sixth distance is the distance between the focusing position R5 and the main surface of the condensing lens 30e.

[0163] Therefore, by reducing the difference in distance between the focusing positions R4 and R5 and the main surface of the focusing lens 30e, the difference in the expansion angle of the portions B4 and B5 passing through the focusing lens 30e can be reduced. Furthermore, by making the second distance between the main surface of the lens 15e with the smaller aperture and the focusing position R5 shorter than the first distance between the main surface of the lens 14e and the focusing position R4, the difference in the beam diameter of the portions B4 and B5 passing through the focusing lens 30e can be reduced. Therefore, even if the irradiation surface 5 moves parallel to the travel direction of the laser beam B, the reduction in the uniformity of the laser beam B can be suppressed.

[0164] (14) According to the second embodiment, lenses 14e and 15e and condenser lens 30e are configured such that condensing positions R4 and R5, which correspond to the rear focal points of lenses 14e and 15e respectively, are located at the front focal plane F of condenser lens 30e.

[0165] Therefore, by positioning the rear focal points of lenses 14e and 15e at the front focal plane F of condenser lens 30e, the portions B4 and B5 passing through condenser lens 30e can become approximately parallel light, outputting a high-quality laser beam B to the irradiation surface 5.

[0166] (15) According to the second embodiment, the numerical apertures of lenses 14e and 15e are equal to each other.

[0167] Therefore, by making the numerical apertures equal, the widths of the optical paths passing through the condenser lens 30e (parts B4 and B5) are made consistent, enabling the output of a high-quality laser beam B to the irradiation surface 5.

[0168] In other respects, the second implementation method is the same as the first implementation method.

[0169] 6. A lens array comprising a first cylindrical lens (10g) and a second cylindrical lens (20g).

[0170] 6.1 Structure

[0171] Figure 21 This illustrates the structure of the homogenizer 1g in the third embodiment. Alternatively, homogenizer 1g can be used instead. Figure 1 The homogenizer 1a is shown. Homogenizer 1g differs from homogenizers 1c to 1f in that it includes a first cylindrical lens 10g, a second cylindrical lens 20g, and condenser lenses 30g and 40g. The first cylindrical lens 10g and the second cylindrical lens 20g constitute the lens array of this disclosure. The laser beam B passing through the first cylindrical lens 10g is incident on the second cylindrical lens 20g. The condenser lenses 30g and 40g cause the portions of the laser beam B passing through the first cylindrical lens 10g and the second cylindrical lens 20g to coincide on a common illumination surface.

[0172] Lenses 11g to 17g, which constitute the first cylindrical lens 10g, each have mutually parallel focal axes, which are, for example, parallel to the X direction. Lenses 21g to 27g, which constitute the second cylindrical lens 20g, each have mutually parallel focal axes, which are not parallel to the focal axes of lenses 11g to 17g, for example, parallel to the Y direction.

[0173] Condensing lens 30g includes a cylindrical lens having a focal axis parallel to the focal axis of lens 11g to 17g. Condensing lens 40g includes a cylindrical lens having a focal axis parallel to the focal axis of lens 21g to 27g.

[0174] Regarding the fact that a smaller spatial coherence length Xc reduces the spacing P of lenses 11g-17g and lenses 21g-27g, the same applies to homogenizer 1g and homogenizers 1c-1f. For example, the spatial coherence length Xc of the portion of laser beam B incident on lens 15g is smaller than that of the portion incident on lens 14g, and the spacing P of lens 15g is smaller than that of lens 14g. Similarly, the spatial coherence length Xc of the portion of laser beam B incident on lens 25g is smaller than that of the portion incident on lens 24g, and the spacing P of lens 25g is smaller than that of lens 24g.

[0175] Lens 14g corresponds to the first lens in this disclosure, and lens 15g corresponds to the second lens in this disclosure. The focal axis of lens 14g corresponds to the first focal axis in this disclosure, and the focal axis of lens 15g corresponds to the second focal axis in this disclosure. The focal axis of condenser lens 30g corresponds to the third focal axis in this disclosure.

[0176] Lens 24g corresponds to the fourth lens in this disclosure, and lens 25g corresponds to the fifth lens in this disclosure. The portion of the laser beam B incident on lens 24g corresponds to the fourth portion in this disclosure, and the portion incident on lens 25g corresponds to the fifth portion in this disclosure. The focal axis of lens 24g corresponds to the fourth focal axis in this disclosure, and the focal axis of lens 25g corresponds to the fifth focal axis in this disclosure.

[0177] 6.2 Function

[0178] (16) According to the third embodiment, lenses 14g and 15g constitute the first cylindrical lens 10g included in the lens array, and each has a focal axis that is parallel to each other.

[0179] Therefore, by using the first cylindrical lens 10g, the gap between lenses 14g and 15g can be reduced.

[0180] (17) According to the third embodiment, the condenser lens 30g includes a cylindrical lens having a focal axis parallel to the focal axis of the lenses 14g and 15g.

[0181] Therefore, by using a condenser lens 30g having a focal axis corresponding to the focal axes of lenses 14g and 15g, the portions of the laser beam B that have passed through lenses 14g and 15g can be made to overlap on a common irradiation surface 5.

[0182] (18) According to the third embodiment, the lens array includes a second cylindrical lens 20g, to which the laser beam B, passing through the first cylindrical lens 10g, is incident. The second cylindrical lens 20g includes: a lens 24g, to which a portion of the laser beam B is incident; and a lens 25g, to which a portion of the laser beam B, different from the portion incident on the lens 24g and having a spatial coherence length Xc smaller than that of the portion incident on the lens 24g, is incident. The spacing P of the lenses 25g is smaller than the spacing P of the lenses 24g. Lenses 24g and 25g each have focal axes that are parallel to each other and not parallel to the focal axes of lenses 14g and 15g. Condensing lenses 30g and 40g cause the portions of the laser beam B incident on lenses 24g and 25g and passing through the lens array to coincide on a common illumination surface 5.

[0183] Therefore, by using a second cylindrical lens 20g that is not parallel to the focal axis of the first cylindrical lens 10g, it is possible to improve the uniformity of light distribution in multiple directions and suppress the generation of interference fringes.

[0184] In other respects, the third implementation method is the same as the first and second implementation methods.

[0185] 7. The homogenizer 1c located inside the laser amplifier PO is the irradiation surface 5.

[0186] 7.1 Structure

[0187] Figure 22 The structure of the laser system 100h in the fourth embodiment is shown. The laser system 100h includes a laser oscillator MO, a homogenizer 1c, a laser amplifier PO, and an optical element 9. Any homogenizer from homogenizers 1d to 1g can be used instead of homogenizer 1c. The laser beam B, after passing through homogenizer 1c, is amplified by the laser amplifier PO and output from the laser system 100h via the optical element 9.

[0188] Figure 23 This shows the detailed structure of the laser system 100h. The laser oscillator MO includes a laser cavity 70, a narrowband module 74, and an output coupling mirror 75.

[0189] A laser cavity 70 is positioned in the optical path of a laser resonator comprised of a narrowband module 74 and an output coupling mirror 75. Two windows 701 and 702 are provided in the laser cavity 70. Discharge electrodes 711 and 712 are housed within the laser cavity 70. Discharge electrodes 711 and 712 are connected to a pulsed power supply (not shown). A laser gas, serving as the laser medium, is contained within the laser cavity 70. The laser gas may include, for example, argon, fluorine, and neon. Alternatively, the laser gas may include, for example, krypton, fluorine, and neon.

[0190] The narrowband module 74 includes wavelength selection elements such as a prism 741 and a grating 742. The output coupling mirror 75 is composed of partial reflectors.

[0191] A high-reflectivity mirror 761, a homogenizer 1c, and a high-reflectivity mirror 762 are sequentially arranged in the optical path of the laser beam B output from the output coupling mirror 75.

[0192] The laser amplifier PO includes a laser cavity 80, a rear mirror 84, and an output coupling mirror 85. The laser cavity 80, the output coupling mirror 85, and the windows 801 and 802, and the discharge electrodes 811 and 812 attached to the laser cavity 80 are the same as the corresponding components in the laser oscillator MO.

[0193] The rear mirror 84 is positioned in the optical path of the laser beam B reflected by the high-reflectivity mirror 762. The rear mirror 84 is composed of partial mirrors. The rear mirror 84 and the output coupling mirror 85 constitute a laser resonator.

[0194] Optical element 9 includes, for example, a beam steering unit 96 and an optical pulse broadener 99. The beam steering unit 96 includes high-reflectivity mirrors 961 and 962.

[0195] An optical pulse stretcher 99 is configured in the optical path of the laser beam B that has passed through the beam steering unit 96. The optical pulse stretcher 99 includes a beam splitter 995 and a first concave mirror 991 to a fourth concave mirror 994.

[0196] 7.2 Actions

[0197] 7.2.1 Operation of the Laser Oscillator (MO)

[0198] In the laser oscillator MO, a pulsed power supply (not shown) generates a pulsed high voltage, which is applied between discharge electrodes 711 and 712. When the high voltage is applied between discharge electrodes 711 and 712, a discharge occurs between them. The energy from this discharge excites the laser gas within the laser cavity 70 to transition to a higher energy level. The excited laser gas then emits light of a wavelength corresponding to the energy level difference as it transitions to a lower energy level.

[0199] Light generated within the laser cavity 70 exits through windows 701 and 702 to the outside of the laser cavity 70. The light exiting from window 701 has its beam width broadened by prism 741 and enters grating 742. The light entering grating 742 from prism 741 is reflected by multiple grooves in grating 742 and diffracted in a direction corresponding to the wavelength of the light. Grating 742 is configured in a Litterrow configuration such that the angle of incidence of the light entering grating 742 from prism 741 coincides with the diffraction angle of the diffracted light at the desired wavelength. Thus, light near the desired wavelength returns to the laser cavity 70 via prism 741.

[0200] The output coupling mirror 75 allows a portion of the light emitted from the window 702 to pass through and be output, while the other portion is reflected back to the laser cavity 70.

[0201] Thus, the light emitted from the laser cavity 70 reciprocates between the narrowing module 74 and the output coupling mirror 75. This light is amplified each time it passes through the discharge space between the discharge electrodes 711 and 712. Furthermore, the light is narrowed each time it is folded back in the narrowing module 74. The narrowed light, thus undergoing laser oscillation, is output as laser beam B from the output coupling mirror 75.

[0202] 7.2.2 Operation of Laser Amplifier PO

[0203] The laser beam B output from the output coupling mirror 75 is incident on the homogenizer 1c via the high-reflectivity mirror 761. The irradiation surface 5 for the laser beam B emitted from the homogenizer 1c is an imaginary surface located inside the laser amplifier PO. The irradiation surface 5 is preferably located between the discharge electrodes 811 and 812. The laser beam B emitted from the homogenizer 1c is incident on the laser cavity 80 via the high-reflectivity mirror 762 and the rear mirror 84.

[0204] Synchronously with the laser beam B incident on the laser cavity 80, a pulsed power supply (not shown) generates a pulsed high voltage in the laser amplifier PO, which is applied between the discharge electrodes 811 and 812.

[0205] When a high voltage is applied between discharge electrodes 811 and 812, a discharge occurs between them. The energy from this discharge amplifies the laser beam B incident on the laser cavity 80.

[0206] The amplified light within the laser cavity 80 reciprocates between the rear mirror 84 and the output coupling mirror 85. This light is amplified each time it passes through the discharge space between discharge electrodes 811 and 812. The amplified laser beam B is then output from the output coupling mirror 85.

[0207] 7.2.3 Operation of the Optical Pulse Stretcher 99

[0208] The laser beam B output from the output coupler 85 is directed by the beam steering unit 96. Figure 23 The light incident from the right direction onto the beam splitter 995 of the optical pulse stretcher 99. The beam splitter 995 causes the light to... Figure 23 A portion of the laser beam B incident from the right passes through and exits as beam Ba, while the other portion... Figure 23 The laser beam B is reflected downwards. The reflected laser beam B is then reflected sequentially by the first concave mirror 991 to the fourth concave mirror 994, towards... Figure 23 The beam is incident on the beam splitter 995 from the bottom direction.

[0209] The laser beam B incident from the beam steering unit 96 has its beam cross-section imaged on the beam splitter 995 by the first concave mirror 991 to the fourth concave mirror 994 at a 1:1 ratio. The beam splitter 995 directs the beam from the fourth concave mirror 994... Figure 23 A portion of the downward-incident laser beam B is directed towards Figure 23 It is reflected to the right and emitted as beam Bb.

[0210] Between beams Ba and Bb, there exists a time difference corresponding to the optical path length of the delay optical path formed by the first concave mirror 991 to the fourth concave mirror 994. By spatially aligning beams Ba and Bb, a laser beam B with an extended pulse width can be emitted.

[0211] 7.3 Function

[0212] (19) According to the fourth embodiment, the laser system 100h includes a laser amplifier PO, and a laser beam B passing through a focusing lens 30c is incident on the laser amplifier PO. The irradiation surface 5 is an imaginary surface located inside the laser amplifier PO.

[0213] As a result, the uniformity of the light distribution is improved. By incident a laser beam B, whose interference fringe generation is suppressed, onto the laser amplifier PO, the uniformity of the light distribution of the laser beam B amplified by the laser amplifier PO can be improved. Furthermore, by suppressing the localization of high energy in the laser beam B incident on the subsequent optical element 9, the lifetime of the optical element 9 can be improved.

[0214] 8. Other

[0215] 8.1 Manufacturing methods for electronic devices

[0216] Figure 24 The structure of the exposure system is shown. The exposure system includes a laser system 100h and an exposure apparatus 200. Alternatively, a laser system 100a can be used instead of the laser system 100h, in which the homogenizer 1a is replaced by any homogenizer 1c to 1g. The laser system 100h is configured to output a laser beam B to the exposure apparatus 200.

[0217] The exposure apparatus 200 includes an illumination optics system 201 and a projection optics system 202. The illumination optics system 201 illuminates a mask pattern (not shown) disposed on a mask stage RT using a laser beam B incident from the laser system 100h. The projection optics system 202 projects a reduced image of the laser beam B passing through the mask onto a workpiece (not shown) disposed on a workpiece stage WT. The workpiece is a photosensitive substrate such as a semiconductor wafer coated with photoresist.

[0218] The exposure apparatus 200 exposes the workpiece to a laser beam B reflecting the mask pattern by synchronously and parallelly moving the mask stage RT and the workpiece stage WT. After the mask pattern is transferred onto the semiconductor wafer through the above exposure process, electronic devices can be manufactured through multiple processes.

[0219] 8.2 Supplement

[0220] The foregoing description is not limiting but merely illustrative. Therefore, it will be apparent to those skilled in the art that modifications can be made to the embodiments of this disclosure without departing from the claims. Furthermore, combinations of embodiments of this disclosure will also be apparent to those skilled in the art.

[0221] Unless explicitly stated otherwise, the terms used throughout this specification and the claims shall be construed as “non-restrictive” terms. For example, terms such as “comprising,” “having,” “possessing,” and “complementing” shall be construed as “not excluding the presence of constituent elements other than those described.” Furthermore, the modifier “a” shall be construed as meaning “at least one” or “one or more.” Additionally, the term “at least one of A, B, and C” shall be construed as “A,” “B,” “C,” “A+B,” “A+C,” “B+C,” or “A+B+C.” Moreover, it shall be construed as also including combinations thereof with portions other than “A,” “B,” and “C.”

Claims

1. A laser system comprising: Laser oscillator; A lens array, comprising a first lens and a second lens, wherein a first portion of a laser beam output from the laser oscillator is incident on the first lens, and a second portion of the laser beam, different from the first portion, is incident on the second lens, wherein the spatial coherence length of the second portion is smaller than the spatial coherence length of the first portion, and the spacing between the second lenses is smaller than the spacing between the first lenses. as well as A focusing lens that causes the first and second portions of the lens array to coincide on a common illumination surface.

2. The laser system according to claim 1, wherein, The lens array further includes a third lens, to which a third portion of the laser beam, different from both the first and second portions, is incident. The spatial coherence length of this third portion is smaller than that of the second portion, and the spacing between the third lenses is smaller than that between the second lenses. The condensing lens causes the first to third portions of the lens array to coincide on a common illumination surface.

3. The laser system according to claim 1, wherein, The distance between the first part and the center of the beam cross section of the laser beam is shorter than the distance between the second part and the center.

4. The laser system according to claim 1, wherein, The spacing between the first lenses is greater than or equal to the maximum value of the spatial coherence length of the first portion. The spacing between the second lenses is greater than or equal to the maximum value of the spatial coherence length of the second part.

5. The laser system according to claim 1, wherein, The spacing between the first lenses is greater than the minimum spatial coherence length of the first portion. The spacing between the second lenses is greater than the minimum spatial coherence length of the second part.

6. The laser system according to claim 5, wherein, The spacing between the first lenses is less than the maximum value of the spatial coherence length of the first portion. The spacing between the second lenses is less than the maximum value of the spatial coherence length of the second part.

7. The laser system according to claim 1, wherein, The spacing between the first lenses is greater than or equal to the average spatial coherence length of the first portion. The spacing between the second lenses is greater than or equal to the average spatial coherence length of the second portion.

8. The laser system according to claim 1, wherein, The aperture size of the second lens is smaller than that of the first lens.

9. The laser system according to claim 8, wherein, The second distance is longer than the first distance. The second distance is the distance between the main surface of the second lens and the second focusing position of the second portion of the second lens. The first distance is the distance between the main surface of the first lens and the first focusing position of the first portion of the first lens.

10. The laser system according to claim 9, wherein, The difference between the third distance and the fourth distance is less than the difference between the first distance and the second distance. The third distance is the distance between the main surface of the first lens and the main surface of the condenser lens, and the fourth distance is the distance between the main surface of the second lens and the main surface of the condenser lens.

11. The laser system according to claim 9, wherein, The sixth distance between the second focusing position and the main surface of the focusing lens is shorter than the fifth distance between the first focusing position and the main surface of the focusing lens.

12. The laser system according to claim 1, wherein, The aperture size of the second lens is smaller than that of the first lens. The fourth distance between the principal surface of the second lens and the principal surface of the condenser lens is shorter than the third distance between the principal surface of the first lens and the principal surface of the condenser lens.

13. The laser system according to claim 1, wherein, The second distance is shorter than the first distance. This second distance is the distance between the principal surface of the second lens and the second focusing position through the second portion of the second lens. The first distance is the distance between the principal surface of the first lens and the first focusing position through the first portion of the first lens. The difference between the fifth distance and the sixth distance is smaller than the difference between the first distance and the second distance. The fifth distance is the distance between the first focusing position and the main surface of the focusing lens, and the sixth distance is the distance between the second focusing position and the main surface of the focusing lens.

14. The laser system according to claim 1, wherein, The first lens, the second lens, and the condenser lens are configured such that the rear focal point of each of the first lens and the second lens is located at the front focal plane of the condenser lens.

15. The laser system according to claim 14, wherein, The numerical apertures of the first lens and the second lens are equal.

16. The laser system according to claim 1, wherein, The first lens and the second lens constitute the first cylindrical lens included in the lens array, and the first lens and the second lens have a first focal axis and a second focal axis that are parallel to each other.

17. The laser system according to claim 16, wherein, The condenser lens includes a cylindrical lens having a third focal axis parallel to the first focal axis and the second focal axis.

18. The laser system according to claim 16, wherein, The lens array further includes a second cylindrical lens, to which the laser beam passing through the first cylindrical lens is incident. The second cylindrical lens comprises: A fourth lens, a fourth portion of the laser beam is incident on the fourth lens; and A fifth lens is formed by a portion of the laser beam that is different from the fourth portion. The spatial coherence length of this fifth portion is smaller than that of the fourth portion, and the spacing between the fifth and fourth lenses is smaller than that between the fourth lenses. The fourth lens and the fifth lens have a fourth focal axis and a fifth focal axis that are parallel to each other, and the fourth focal axis and the fifth focal axis are not parallel to the first focal axis and the second focal axis. The condenser lens causes the fourth and fifth portions of the lens array to coincide on a common illumination surface.

19. The laser system according to claim 1, wherein, The laser system also includes a laser amplifier, to which the laser beam passing through the condenser lens is incident. The irradiation surface is an imaginary surface located inside the laser amplifier.

20. A method for manufacturing an electronic device, comprising the following steps: Using a laser system to generate a laser beam, The laser beam is output to the exposure device. The laser beam is used to expose a photosensitive substrate within the exposure apparatus to manufacture the electronic device. This laser system has the following features: Laser oscillator; A lens array, comprising a first lens and a second lens, wherein a first portion of a laser beam output from the laser oscillator is incident on the first lens, and a second portion of the laser beam, different from the first portion, is incident on the second lens, wherein the spatial coherence length of the second portion is smaller than the spatial coherence length of the first portion, and the spacing between the second lenses is smaller than the spacing between the first lenses. as well as A focusing lens that causes the first and second portions of the lens array to coincide on a common illumination surface.

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