Projection optical system, exposure apparatus, and method of manufacturing article

Abstract

The present invention relates to a projection optical system, an exposure apparatus, and a manufacturing method of an article. A projection optical system capable of simultaneously achieving high specification and good optical performance is provided. A projection optical system having a concave mirror and a convex mirror and projecting an image of a pattern of an illumination region outside an optical axis on an object plane in order of the concave mirror, the convex mirror, and the concave mirror to an image plane is provided with a lens group disposed on an optical path between the concave mirror and the convex mirror, the lens group including a first lens having a first aspherical surface and a second lens disposed between the first lens and the convex mirror and having a second aspherical surface, in the first aspherical surface of the first lens, when optical power at a position Pcr and a position Psm of the first aspherical surface is set to optical power on an optical axis in the first aspherical surface is set to, the second aspherical surface of the second lens has a region for compensating for a change in optical power from the position Pcr to the position Psm in the first aspherical surface.

Description

Technical Field

[0001] This invention relates to projection optical systems, exposure apparatuses, and methods for manufacturing articles. Background Technology

[0002] In the photolithography process, which is used in the manufacturing of flat panel displays (FPDs) such as semiconductor devices, liquid crystal displays, or organic EL display devices, an exposure apparatus equipped with a projection optics system can be used. In the exposure apparatus, the pattern of the original (intermediate mask, mask) is projected onto a substrate (wafer, glass plate, etc.) coated with a photosensitive material (resist) via the projection optics system, thereby transferring the pattern of the original onto the substrate.

[0003] As a projection optical system for exposure apparatus, for example, a telecentric reflection-refraction type optical system is known that performs three reflections in total using concave and convex mirrors. In such a projection optical system, by using aspherical surfaces in the lenses and / or mirrors constituting it, the image of the illumination area (e.g., an arc-shaped area) on the original plate disposed on the object surface can be projected onto the substrate at the same magnification or at a higher magnification.

[0004] Patent Document 1 proposes a structure for a projection optical system that can increase throughput by widening the arc-shaped illumination area (slit width) on the original image. Patent Document 2 proposes a structure for a projection optical system that can increase the imaging magnification (projection magnification). Patent Document 3 proposes a structure for a projection optical system with magnification used to suppress the enlargement of the original image associated with the enlargement of the device.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2006-78631

[0008] Patent Document 2: Japanese Patent Application Publication No. 2006-78592

[0009] Patent Document 3: Japanese Patent Application Publication No. 2008-89832

[0010] Non-patent literature

[0011] Non-Patent Document 1: Akio Suzuki, “Analysis of the Equal Magnification Two-Element Lens System”, Optics, Vol. 14, No. 5, October 1985. Summary of the Invention

[0012] As market demands for exposure equipment have evolved, such as requiring higher resolution, larger screen sizes, and increased production efficiency, it is necessary to improve the resolution of projection optical systems and expand the exposure range. In other words, the projection optical systems of exposure equipment require further upgrades, including higher resolution, shorter wavelengths, and larger projection areas on the image plane.

[0013] In the projection optical systems described in Patent Documents 1 and 2, two lenses and an aspherical surface are positioned near the convex mirror, but the optical performance (especially the correction of sagittal and meridional chromatic aberration and lateral aberration) is insufficient. Therefore, it is not suitable for further increasing the field of view (NA) or expanding the projection area. Furthermore, in the projection optical system described in Patent Document 3, a single lens with two aspherical surfaces is positioned near the convex mirror, but the optical performance (especially the correction of sagittal halos, image height difference, chromatic aberration, and lateral aberration) is insufficient. Therefore, it is not suitable for further increasing the NA or expanding the projection area.

[0014] Therefore, the purpose of this invention is to provide a projection optical system that can simultaneously achieve high standardization and good optical performance.

[0015] To achieve the above objectives, a side projection optical system of the present invention includes a concave mirror and a convex mirror, such that an image of a pattern in an illumination area located outside the optical axis on an object surface is reflected and projected onto an image plane in the order of the concave mirror, the convex mirror, and the concave mirror. The projection optical system is characterized by having a lens group disposed in the optical path between the concave mirror and the convex mirror, the lens group including a first lens having a first aspherical surface and a second lens having a second aspherical surface disposed between the first lens and the convex mirror. In the first aspherical surface of the second lens, the endpoint closer to the optical axis among the two endpoints on the line where the meridional plane bisecting the illumination area intersects the illumination area is designated Yi, and the endpoint farther from the optical axis is designated Ya. The position where the principal ray from endpoint Yi is incident on the first aspherical surface is designated Pcr, and the position where the sagittal edge ray from endpoint Ya is incident on the first aspherical surface is designated Psm. The optical power at positions Pcr and Psm is respectively set as... Let the optical power on the optical axis of the first aspherical surface be set as When, satisfy The second aspherical surface of the second lens has a region for compensating for the change in optical power from position Pcr to position Psm in the first aspherical surface.

[0016] Further objectives or other aspects of the invention will become clear from the preferred embodiments described below with reference to the accompanying drawings.

[0017] According to the present invention, for example, a projection optical system capable of simultaneously achieving high standardization and good optical performance can be provided. Attached Figure Description

[0018] Figure 1 This is a schematic diagram showing the structure of the projection optical system of Embodiment 1.

[0019] Figure 2A This is a diagram showing the illuminated area on the surface of an object.

[0020] Figure 2B This is a diagram illustrating the structure of the lens group in Embodiment 1.

[0021] Figure 3 This is a diagram illustrating the variation of local optical power on an aspherical surface in the projection optical system of Embodiment 1.

[0022] Figure 4A This is a longitudinal aberration diagram in the projection optical system of Example 1.

[0023] Figure 4B This is a diagram of lateral aberration in the projection optical system of Example 1, and a diagram showing wavefront aberration along the i-line.

[0024] Figure 5 This is a schematic diagram showing the structure of the projection optical system of Embodiment 2.

[0025] Figure 6 This is a diagram illustrating the variation of local optical power on an aspherical surface in the projection optical system of Embodiment 2.

[0026] Figure 7A This is a longitudinal aberration diagram in the projection optical system of Example 2.

[0027] Figure 7B These are diagrams showing the lateral aberrations in the projection optical system of Example 2 and the wavefront aberrations along the i-line.

[0028] Figure 8 This is a schematic diagram showing the structure of the projection optical system of Embodiment 3.

[0029] Figure 9 This is a diagram showing the variation of local optical power on the aspherical surface in the projection optical system of Embodiment 3.

[0030] Figure 10A This is a longitudinal aberration diagram in the projection optical system of Example 3.

[0031] Figure 10B These are diagrams showing the lateral aberrations in the projection optical system of Example 3 and the wavefront aberrations along the i-line.

[0032] Figure 11This is a schematic diagram showing the structure of the projection optical system of Embodiment 4.

[0033] Figure 12 This is a diagram showing the variation of local optical power of the aspherical surface in the projection optical system of Embodiment 4.

[0034] Figure 13A This is a longitudinal aberration diagram in the projection optical system of Example 4.

[0035] Figure 13B These are diagrams showing the lateral aberrations in the projection optical system of Example 4, and diagrams showing the wavefront aberrations along the i-line.

[0036] Figure 14 This is a schematic diagram showing the structure of the projection optical system of Embodiment 5.

[0037] Figure 15 This is a diagram illustrating the variation of local optical power on an aspherical surface in the projection optical system of Embodiment 5.

[0038] Figure 16A This is a longitudinal aberration diagram in the projection optical system of Example 5.

[0039] Figure 16B These are diagrams showing the transverse aberrations in the projection optical system of Example 5 and wavefront aberrations at a wavelength of 320 nm.

[0040] Figure 17 This is a schematic diagram showing the structure of the projection optical system of Embodiment 6.

[0041] Figure 18 This is a diagram showing the variation of local optical power on the aspherical surface in the projection optical system of Embodiment 6.

[0042] Figure 19A This is a longitudinal aberration diagram in the projection optical system of Example 6.

[0043] Figure 19B These are diagrams showing the transverse aberrations in the projection optical system of Example 6 and wavefront aberrations at a wavelength of 320 nm.

[0044] Figure 20 This is a schematic diagram showing the structure of the projection optical system of Embodiment 7.

[0045] Figure 21 This is a diagram illustrating the variation of local optical power on an aspherical surface in the projection optical system of Embodiment 7.

[0046] Figure 22A This is the longitudinal aberration diagram in the projection optical system of Example 7.

[0047] Figure 22BThese are diagrams of lateral aberrations in the projection optical system of Example 7 and diagrams showing wavefront aberrations along the i-line.

[0048] Figure 23 This is a schematic diagram showing the structure of the projection optical system of Embodiment 8.

[0049] Figure 24 This is a diagram showing the variation of local optical power on the aspherical surface in the projection optical system of Embodiment 8.

[0050] Figure 25A This is a longitudinal aberration diagram in the projection optical system of Example 8.

[0051] Figure 25B These are diagrams showing the lateral aberrations in the projection optical system of Example 8 and the wavefront aberrations along the i-line.

[0052] Figure 26 This is a schematic diagram showing an example of the structure of an exposure apparatus.

[0053] Figure 27 This is a diagram used to illustrate the basic parameters of a two-lens system with equal magnification.

[0054] Figure 28 This is a schematic diagram of a conventional projection optical system.

[0055] Figure 29A It is a longitudinal aberration diagram in a conventional projection optical system.

[0056] Figure 29B These are diagrams of lateral aberrations in conventional projection optical systems and diagrams showing wavefront aberrations along the i-line.

[0057] Figure 30 This is a diagram illustrating the local optical power variation of an aspherical surface in a conventional projection optical system.

[0058] Figure 31 This is a diagram showing the variation of local optical power on an aspherical surface in the projection optical system of Patent Document 1.

[0059] Figure 32 This is a diagram showing the variation of local optical power on an aspherical surface in the projection optical system of Patent Document 1.

[0060] Figure 33 This is a diagram showing the variation of local optical power on an aspherical surface in the projection optical system of Patent Document 1.

[0061] Figure 34 This diagram is used to explain the causes of ghosting and glare.

[0062] (Symbol Explanation)

[0063] PO: Projection optical system; OP: Object plane; IP: Image plane; LG: Lens group; M1, M3: Concave mirrors; M2: Convex mirror Detailed Implementation

[0064] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Furthermore, the invention covered by the claims is not limited to the embodiments described below. Several features are described in the embodiments, but not all of these features are necessarily essential to the invention; moreover, the features can be arbitrarily combined. In addition, in the drawings, the same or identical structures are given the same reference numerals, and repeated descriptions are omitted.

[0065] First, using the aforementioned Non-Patent Document 1, it will be explained why it is not easy to simultaneously achieve high specifications and good optical performance, such as high NA, short wavelength, expanded projection area (effective area) on the image plane, and miniaturization, in a projection optical system used in an exposure apparatus. According to Non-Patent Document 1, it can be seen from, for example, equation (21) of Non-Patent Document 1, that the transverse aberration is related to the fourth power of θ, The residual wavefront aberration is proportional to the cube of h×NA. 7 Proportional. h θ Figure 27 (with non-patent document 1) Figure 1 As shown in the diagram, these parameters relate to the object height, NA, and principal ray angle, respectively. That is, if in order to increase... Furthermore, by increasing the distances h and θ between the convex mirror and the light rays above and below it, high NA (nanoscale) is achieved. Increasing h and θ expands the projection area, and increasing θ to reduce the diameter of the concave mirror enables miniaturization. However, in this case, the amount of aberrations mentioned above may become enormous. Additionally, for shorter wavelengths, the nitrile material used is almost limited to quartz, making correction of image plane curvature, astigmatism, and lateral aberrations, particularly those involving color, difficult. Further increasing h to expand the projection area may make correction even more challenging. Therefore, through dedicated research, the inventors have discovered a structure for a projection optical system that simultaneously achieves high specifications and good optical performance. Embodiments of the projection optical system according to this invention will be described below.

[0066] [Example 1]

[0067] Example 1 illustrates the projection optical system involved in this invention. Figure 1 This is a schematic diagram illustrating the structure of the projection optical system PO1 according to Embodiment 1 of the present invention. The projection optical system PO1 has a concave mirror M1 and a convex mirror M2, which projects an image of a pattern in an illumination area located outside the optical axis on the object surface onto the image plane by reflecting the image in the order of concave mirror M1, convex mirror M2, and then back to concave mirror M1. Figure 1In this diagram, OA represents the optical axis, OP represents the object plane, IP represents the image plane, L1 represents the first aspherical lens, SG represents the refractive optical component, and LG represents the lens group. When the projection optical system PO1 is used in an exposure apparatus, the original image can be placed on the object plane OP of the projection optical system PO1, and the substrate can be placed on the image plane IP of the projection optical system PO2. The light beam emitted from the object plane OP at NA0.1 passes through or is reflected in each optical element in the optical path sequence from the object plane OP as L1→SG→M1→LG→M2→LG→M1→SG→L1, and is imaged at an equal magnification on the image plane IP. That is, the projection optical system PO1 of Embodiment 1 is an equal-magnification system that projects the image of the illumination area IR in the object plane OP (specifically, the image of the pattern set in the illumination area IR) onto the image plane IP at an equal magnification. Furthermore, the pupil position (pupil plane) of the projection optical system PO1 can be a convex mirror M2, and an aperture stop can be placed near the convex mirror M2. Additionally, the refractive optical component SG can be used to adjust the imaging magnification or distortion aberration.

[0068] exist Figure 1 In the illustrated structural example, the lens group LG is disposed in the optical path between the concave mirror M1 and the convex mirror M2, and may include lens L2 and lens L3. Lens L2 can also be understood as a first lens having a first aspherical surface, and lens L3 as a second lens disposed between lens L2 (the first lens) and the convex mirror M2 and having a second aspherical surface. In this embodiment 1, lens L2 is a meniscus lens with its convex surface facing the concave mirror side, and the concave mirror side of lens L2 is an aspherical surface (the first aspherical surface). Similarly, the convex mirror side of lens L3 is an aspherical surface (the second aspherical surface).

[0069] Figure 2A The illumination area IR in the object surface OP is shown. The illumination area IR can also be understood as the area of ​​the original material disposed on the object surface OP that is illuminated by the slit light, sometimes referred to as the effective area. The illumination area IR is located outside the optical axis (outside the optical axis OA) on the object surface OP, excluding the optical axis OA. In this embodiment 1, an arc-shaped illumination area IR is described, but the shape of the illumination area IR is not limited to an arc shape and can also be rectangular. In addition, in this embodiment 1, as Figure 2AAs shown, the width of the illumination area IR, i.e., the length along the Y-axis, is denoted as the slit width Sw, and the length along the X-axis is denoted as the illumination width (exposure width) W. The minimum object height within the meridional plane of the illumination area IR is denoted as the lower limit Yi, and the maximum object height is denoted as the upper limit Ya. The meridional plane can be defined as the surface (meridian plane) that includes the principal ray passing through the center of gravity of the illumination area IR as the object point and the optical axis OP; that is, it is defined as the surface that includes the optical axis OP and bisects the illumination area IR. Furthermore, the lower limit Yi can also be understood as the endpoint closer to the optical axis OP among the two endpoints on the line where the illumination area IR and the meridional plane intersect, and the upper limit Ya can also be understood as the endpoint farther from the optical axis OP among these two endpoints. In the projection optical system PO1, a larger illumination width W allows for a larger image size during simultaneous exposure, and a larger slit width Sw increases the exposure illuminance, thus increasing throughput (i.e., production efficiency).

[0070] Figure 2B The structure of the lens group LG in this embodiment 1 is shown. Figure 2B (a) shows an enlarged view of the lens group LG (lenses L2, L3) and the convex mirror M2. Figure 2B (b) shows the position of the light beam in the aspherical surface L2R1 (the concave mirror side surface) of lens L2. Figure 2B (c) shows the local optical power variation in each aspherical surface. As described above, the lens group LG of this embodiment 1 includes a lens L2 disposed on the side closest to the concave mirror M1 and serving as a meniscus lens with its convex surface facing the concave mirror M1, and a lens L3 disposed between lens L2 and the convex mirror M2. The surface L2R1 on the concave mirror M2 side of lens L2 and the surface L3R2 on the convex mirror M2 side of lens L3 are aspherical surfaces, and these surfaces will sometimes be referred to as aspherical surface L2R1 and aspherical surface L3R2 below.

[0071] exist Figure 2B In (a), the lower limit Yi (endpoint Yi) and the upper limit Ya (endpoint Ya) are represented as the upper ray, principal ray, and lower ray of the object point, respectively. The position Pcr of the principal ray from the lower limit Yi on the aspherical surface L2R1 is indicated by an × symbol. Figure 2B In (b), the beam diameter from the lower limit Yi is represented by a single-dotted line (Yi beam diameter), and the beam diameter from the upper limit Ya is represented by a short-dotted line (Ya beam diameter). Furthermore, the position Pcr on the aspherical surface L2R1 where the principal ray from the lower limit Yi is incident is indicated by an × symbol, and the position Psm on the aspherical surface L2R1 where the sagittal edge ray from the upper limit Ya is incident is indicated by an 〇 symbol. Additionally, in Figure 2BIn (b), long dotted dashed lines represent circles with radii from the optical axis OA to each of positions Pcr and Psm. In this embodiment 1, the aspherical local optical power shape is defined within the area enclosed by these dashed lines. Here, the sagittal edge ray from the upper limit Ya can be understood as either the edge ray within the spherical cap plane from the upper limit Ya, or the edge ray (peripheral ray) among the sagittal rays from the upper limit Ya.

[0072] Figure 2B (c) shows the variation in local optical power in each aspherical surface. The vertical axis represents the position (height) of the aspherical surface in the radial direction, and the horizontal axis represents the local optical power of each aspherical surface (hereinafter sometimes referred to as aspherical local optical power). The numbers on the horizontal axis indicate the numbers of the aspherical surfaces arranged in the order of the optical path starting from the object surface OP; the third is aspherical surface L2R1, the fourth is aspherical surface L3R2, and so on. Furthermore, for the aspherical local optical power shown on the horizontal axis, the direction to the right of the paper indicates the positive direction, and the direction to the left of the paper indicates the negative direction. Figure 2B In (c), the positions Pcr and Psm on the aspherical surface L2R1 are marked with × and 〇 respectively. The positions (heights) of the light rays passing through the positions Pcr and Psm on the aspherical surface L2R1 and incident on the aspherical surface L3R2 are also marked with × and 〇 respectively.

[0073] In order to simultaneously achieve high standardization and good optical performance, the projection optical system of this invention is configured such that the local optical power of the aspherical surface at positions Pcr and Psm in the first aspherical surface of the first lens is respectively set to... When the first aspherical surface satisfies equation (1), equation (1) is... This represents the optical power along the optical axis in the first aspherical surface. Furthermore, the second aspherical surface of the second lens includes features for compensating for the change in optical power from position Pcr to position Psm in the first aspherical surface (from optical power...). Optical focal length (The area of ​​change).

[0074]

[0075] In the case of the projection optical system PO1 in this embodiment 1, as described above, the first lens is lens L2, the first aspherical surface is aspherical surface L2R1, the second lens is lens L3, and the second aspherical surface is aspherical surface L3R2. Furthermore, referring to... Figure 2B In (c), within the aspherical surface L2R1 (the third aspherical surface) which is the first aspherical surface, the local optical power of the aspherical surface changes from position Pcr (× mark) towards position Psm (〇 mark) from... Towards It changes monotonically in the negative direction, satisfying the above equation (1). Furthermore, aspheric surface L3R2 (the fourth aspheric surface), being the second aspheric surface, has a region where the aspheric local optical power changes in the positive direction in a way that compensates for (preferably cancels out) the negative changes in aspheric local optical power in aspheric surface L2R1, which is the first aspheric surface. Specifically, in aspheric surface L3R2, the aspheric local optical power changes monotonically in the positive direction from the position (× mark) of the light ray incident through position Pcr of aspheric surface L2R1 toward the position (〇 mark) of the light ray incident through position Psm of aspheric surface L2R1.

[0076] Next, to clarify the effect (difference in correction mechanism) of the projection optical system structure involved in this invention compared to conventional projection optical systems, the results of attempting to design a conventional projection optical system POc will be explained. In the conventional projection optical system POc, apart from the lens group LG consisting of only one lens L2 with two aspherical surfaces, it has the same... Figure 1 The projection optical system PO1 of Embodiment 1 shown has the same optical specifications (structure, design freedom). The optical specifications of the conventional projection optical system POc are shown in Table 1 below: NA 0.1, illumination width W = 1100 mm, slit width Sw = 100 mm (object height 519 mm ~ 619 mm). Tables 2 and 3 below show numerical examples of various parameters used in the design of the conventional projection optical system POc (the explanation follows the paragraph between equations (6) and (7)). In addition, Figure 28 A schematic diagram of a conventional projection optics system POc is shown. Figure 29A This shows a longitudinal aberration diagram in a conventional projection optical system POC. Figure 29B The diagram shows the transverse aberration and the wavefront aberration RMS of the i-line. Figure 30 This illustrates the variation in local optical power of aspherical surfaces obtained by normalizing the position (height) of each aspherical surface in a conventional projection optical system POc using the effective radius.

[0077] Table 1

[0078]

[0079] Table 2

[0080] Table 3

[0081]

[0082] Face number E F G H J 2 1.027768E-32 1.172377E-38 -6.357370E-44 8.454369E-50 -3.959219E-56 7 -1.136376E-35 2.315646E-41 -2.838338E-47 1.972249E-53 -6.002127E-60 8 2.323703E-29 9.285946E-33 -8.720308E-37 3.056502E-41 -3.872824E-46 9 1.063143E-27 3.006092E-31 -3.833909E-35 1.821633E-39 -3.184245E-44 11 1.063143E-27 3.006092E-31 -3.833909E-35 1.821633E-39 -3.184245E-44 12 2.323703E-29 9.285946E-33 -8.720308E-37 3.056502E-41 -3.872824E-46 13 -1.136376E-35 2.315646E-41 -2.838338E-47 1.972249E-53 -6.002127E-60 18 1.027768E-32 1.172377E-38 -6.357370E-44 8.454369E-50 -3.959219E-56

[0083] Furthermore, normally in aberration diagrams, the display of meridional rays, inferior rays, and sagittal rays is interchanged based on the sign of the entrance pupil position relative to the object plane. However, here, in all aberration diagrams, the superior and inferior rays on the ray diagram are corrected to correspond to those on the aberration diagram. Additionally, in the numerical examples of various parameters shown in Tables 2 and 3, mirrors are inserted immediately before the image plane in a manner that makes the image boundaries positive intervals and positive refractive indices in the longitudinal aberration diagram, and the number of mirror elements is set to an even number. The above settings are used in all embodiments of the present invention described below.

[0084] In the conventional projection optical system POc, based on the design results, from Figures 29A-29B It can be confirmed that the dominant wavelength is 365nm (set as the i-line). For example, as can be seen from the lateral aberration, the following aberrations remain.

[0085] (Aberration 1) The curvature of the meridional image plane of color is corrected at the middle image height, but tends to reverse at the upper and lower image heights (facing the higher image height, short wavelengths are under, long wavelengths are over)

[0086] (Aberration 2) Meridional spherical aberrations (halos) that include color are a deficiency tendency.

[0087] (Aberration 3) Sagittal off-axis spherical aberration (halo) including color; image height facing high is a lack of tendency.

[0088] (Aberration 4) The spherical aberration that dominates low-image-high sagittal halos is excessive tendency.

[0089] Furthermore, as a result, it can be confirmed that the wavefront aberration RMS of the i-line decreases at the object height in the middle, but increases to about 40mλ and 50mλ at the object height at both ends of the slit width.

[0090] The reason for this is that, in either the concave mirror side surface R1 or the convex mirror side surface R2 of lens L2, the change in optical power of the surface is negative in order to correct aberrations 1-3, but positive in order to correct aberration 4. Therefore, it is impossible to simultaneously correct all aberrations 1-4 using only one surface. Furthermore, even considering the aberration correction in both surfaces R1 and R2, since the patellar correction of the entire system is borne by the optical power of the concave and convex mirrors, the optical power of the meniscus lens is close to zero, allowing the bending of surfaces R1 and R2 to function. That is, the sensitivity of aberration correction is similar, thus making it impossible to perform aberration correction independently using each of surfaces R1 and R2. As a result, in Figure 30 In, respectively using (× mark) (〇 mark) indicates the local optical power of the aspherical lens L2 at a position equivalent to the positions Pcr and Psm of the aspherical L2R1 in this embodiment 1, and the difference in optical power between them is extremely small. Therefore, in the projection optical system described in Patent Document 3, which similarly places only one lens with two aspherical surfaces near the convex mirror, as described above, the aberrations may be insufficiently corrected.

[0091] In contrast, according to the structure of the projection optical system PO1 of Embodiment 1 of the present invention, by setting lens L2 in the lens group LG as a meniscus lens with its convex surface facing the concave mirror side, the generation of spherical aberration can be suppressed. That is, aberration 4 can be reduced (suppressed). Furthermore, the aspherical surface L2R1, located on the side closest to the concave mirror among the aspherical surfaces in the lens group LG, is far away from the convex mirror that serves as the pupil position, resulting in a large positional difference in the light rays passing through each image height. Therefore, by making the local optical power variation of the aspherical surface L2R1 from Towards By varying the aberration in the negative direction, aberrations 1 to 3 caused by image height difference can be corrected simultaneously. On the other hand, aberration 4 may increase with only aspherical L2R1, but it is reduced by using aspherical L3R2 of lens L3. Specifically, aspherical L3R2 of lens L3 is positioned near the pupil position, where the positional difference of light passing through each image height is small, so that the local optical power of aspherical L3R2 varies in the positive direction in a way that the optical power change in the negative direction of aspherical L2R1 of lens L2 is compensated. As a result, the uniform component of the aberration corrected by aspherical L2R1 of lens L2 can be corrected, and aberration 4 is mainly corrected, so aberrations 1 to 4 can be corrected well as a whole. Regarding the effect of the above aberration correction, since the light passes through the lens group LG twice before and after reflection by convex mirror M2, the above correction effect can also be increased.

[0092] Furthermore, in the projection optical systems described in Patent Documents 1 and 2, two or more lenses are arranged near the convex mirror. In Patent Document 1, the embodiments using aspherical surfaces in the lens group are Embodiment 1, Embodiment 3, and Embodiment 4. In Patent Document 2, the embodiments using aspherical surfaces in the lens group are Embodiment 3 (same as Embodiment 3 in Patent Document 1) and Embodiment 4 (same as Embodiment 4 in Patent Document 1). To verify this, the present inventors reproduced the aspherical local optical power of Embodiments 1, 3, and 4 of Patent Document 1, and the results are shown below. Figure 31 , Figure 32 , Figure 33 (The vertical axis is standardized using the effective radius). In Figures 31-33 In the various diagrams, the aspherical surface in the lens group is positioned on the aspherical surface closest to the concave mirror side, using... (× mark) (The 〇 mark) indicates the local optical power of the aspherical surface at positions Pcr and Psm as defined above. Furthermore, in subsequent aspherical surfaces, the × and 〇 marks are also used to indicate the incident positions of the light rays passing through positions Pcr and Psm, respectively. For example, from each Figures 31-33 It can be seen that among the aspherical surfaces arranged in a meniscus lens, the aspherical surface arranged on the side closest to the concave mirror is... (× mark) Orientation (〇 mark) changes in the positive direction, and the correction principle is different from that of the projection optical system involved in this invention. Therefore, in the structure of the projection optical system described in Patent Documents 1-2, it is difficult to simultaneously achieve high standardization and good aberration correction.

[0093] Next, in the projection optical system according to the present invention, a more preferred configuration condition for simultaneously achieving high standardization and good optical performance will be described.

[0094] The projection optical system of the present invention can be configured such that the optical power of the second aspherical surface of the second lens (in Embodiment 1, the aspherical surface L3R2 of lens L3) is set to... Set the optical power of convex mirror M2 to... The following equation (2) must be satisfied. Equation (2) is a condition used to correct spherical aberration to a good range, setting the range of lens surfaces including zero optical power. When the value is less than the lower limit (-0.12), it becomes a convex shape, and the positive optical power increases, thus producing particularly high-order deficient spherical aberrations. On the other hand, when the value is greater than the upper limit (0.15), excessive spherical aberrations are easily produced, so low-height sagittal halos also become excessive, resulting in an increased sagittal halo image height difference.

[0095]

[0096] Furthermore, the projection optical system according to the present invention can be configured such that the optical power of the entire lens group LG is set to The optical power of the second lens (lens L3 in Example 1) is set to... The following equation (3) is satisfied. Equation (3) defines the optical power of the lens located closest to the convex mirror among the multiple lenses in the lens group LG. The Pezvalence of the entire optical system is determined by the optical power of the concave mirror M1 and the convex mirror M2, so the optical power of the lens group LG is... This value, approaching zero optical power, can be either positive or negative. Therefore, optical power is defined. The absolute value and the optical power of the second lens The ratio. In the projection optical system PO1 of this embodiment 1, the optical power of the lens L3, which is located closest to the convex mirror, has a positive value. In addition, the optical power of the convex mirror side of the lens L3 is defined by the above formula (2), so in When the value is less than the lower limit (0.08), the optical power of the concave mirror side of the lens L3 increases in the positive direction. In this case, the correction effect of the aforementioned aberrations 1 to 3, which is achieved by constructing the first spherical surface of the first lens in a manner that satisfies the aforementioned formula (1), is reduced (cancels each other out), so it is not preferred. On the other hand, regarding the upper limit, it automatically becomes the optical power of the lens group LG. The same aluminosity can be limited to 1.0 (the preferred upper limit is 0.95).

[0097]

[0098] Furthermore, the projection optical system according to the present invention can be configured such that the first aspherical surface of the first lens (in Embodiment 1, the aspherical surface L2R1 of lens L2) satisfies the following equation (4). When the value is less than the lower limit (-0.95), aberrations 1 to 3 are overcorrected. Therefore, it is difficult to maintain aberration balance due to the positive aspherical local power variation caused by the aspherical L3R2 of the lens L2 (with the aspherical L2R1 positioned closest to the concave mirror) and the lens L3 (positioned between the lens L2 and the convex mirror M2). As a result, excessive retention of short-wavelength meridional image plane curvature (and deficiency of long-wavelength curvature), or excessive retention of the sagittal and higher-order components of meridional halos. On the other hand, when the value is greater than the upper limit (-0.055), the correction effect of aberrations 1 to 3 is insufficient, so aberrations 1 to 3 remain.

[0099]

[0100] Furthermore, the projection optical system according to the present invention can be configured such that when the radius of curvature of the convex mirror M2 is set to Rt, the radius of curvature of the concave mirror side surface of the second lens (lens L3 in Embodiment 1) is set to Rm1, and the radius of curvature of the convex mirror side surface of the second lens is set to Rm2, the following equation (5) is satisfied. In the projection optical system PO1 of Embodiment 1, the concave mirror side surface of the second lens refers to the side of the lens L3 opposite to the aspherical surface L3R2, and the convex mirror side surface of the second lens refers to the aspherical surface L3R2 of the lens L3. Equation (5) is a condition for suppressing unwanted light caused by multiple reflections from the convex mirror M2 and the lens surface arranged near the convex mirror in the lens group LG. When the radius of curvature of a lens surface located near a convex mirror M2 is close to that of the convex mirror M2, the paraxial back position of the lens surface, which does not require light and functions as a reflecting surface, becomes the vicinity of the image plane, sometimes causing ghosting and glare. Figure 34 The light path at this point is shown. A representative dashed line pattern represents the light rays incident on the lens by solid arrows and reflected by each lens surface. As one countermeasure to suppress unwanted light, reducing the reflectivity of the anti-reflection film on the lens surface can be cited. However, instead of this, or additionally, in the design of the projection optical system, it is preferable to consider the radius of curvature of the lens surface that produces unwanted light so that its paraxial back position is far away from the image plane. When the value of (Rt / Rm1) or (Rt / Rm2) in Equation (5) is 1, the radius of curvature of the convex mirror is the same as the radius of curvature of the lens surface, so the paraxial back position of the unwanted light is closest to the image plane, which is not preferred. In Equation (5), the upper limit of (Rt / Rm1) or (Rt / Rm2) is set to 0.31, so that the radius of curvature of the lens surface is greater than the radius of curvature of the convex mirror. Furthermore, if it is a negative value, the paraxial back position of the unwanted light is significantly away from the image plane, which is preferred. With an upper limit of 0.31, the paraxial back position where no light is needed is approximately 1300 mm. With NA 0.1, the beam diameter on the image plane is as large as 260 mm, thus reducing (suppressing) the illuminance of unwanted light.

[0101] Rt / Rm1≤0.31 and Rt / Rm2≤0.31···(5)

[0102] Furthermore, the projection optical system of this invention can be configured such that, as shown in equation (6) below, the angle 2θ from the principal ray of the maximum object height incident from the concave mirror M1 onto the lens group LG is greater than 30 degrees. The angle 2θ is intended to be determined with reference to the foregoing. Figure 27Equation (6) is the condition for achieving miniaturization of the projection optical system. In the projection optical system of the present invention, by appropriately setting the shape of the aspherical surfaces (local optical power variation) in the lens group LG, the aberration correction capability is improved, thereby shortening the optical power configuration of the concave mirror M1 and the convex mirror M2. Therefore, the effective diameter of the concave mirror M1 can also be shortened, achieving miniaturization. For comparison, in Embodiments 1, 2, and 4 of Patent Document 1, the angle 2θ becomes as small as 19.9°, 19.2°, and 26.8°, respectively, so the projection optical system is enlarged when high NA and expanded illumination area are achieved.

[0103] 2θ>30°···(6)

[0104] Next, a specific structural example of the projection optical system PO1 in Embodiment 1 will be described. Regarding the structure of the projection optical system PO1 in Embodiment 1, using... Figure 1 As previously stated. Table 4 below shows the optical specifications of the projection optical system PO1 in this embodiment 1, and also records... Figure 2A The elements shown are as follows. The projection optical system PO1 in this embodiment 1 has an NA0.1, but achieves a large screen with an illumination width of 1100mm and a slit width of 100mm, improving production efficiency. Furthermore, Tables 5 and 6 below show numerical examples of various parameters in the projection optical system PO1 of this embodiment 1. In Table 5, "Surface Number" indicates the number assigned to the multiple surfaces of the projection optical system PO1 from the object surface OP according to the optical path sequence; "Aspherical Setting" indicates whether each surface is aspherical; surfaces marked "ASP" are aspherical. "R" represents the radius of curvature (mm), "D" represents the surface spacing (mm), and "glass" represents the nitrate material. The refractive index of air is set to 1; the portion multiplied by "-1" in "glass" indicates reflection, and the portion marked "SiO2" indicates that the nitrate material is synthetic quartz. Table 5 also shows the refractive index for each wavelength. In addition, “asp_data” shown in Table 6 is the aspheric coefficient. All the aspheric surfaces in the projection optical system PO1 of this embodiment 1 can be defined by the aspheric form expressed by the following equation (7). The projection optical system PO1 of this embodiment 1, as shown in Table 7 below, satisfies all the configuration conditions of the above equations (1) to (6).

[0105] z = (1 / R)h 2 / (1+(1-(1+k)(1 / R) 2 h 2 ) 1 / 2 )

[0106] +Ah 4 +Bh 6 +Ch 8+Dh 10 +Eh 12

[0107] +Fh 14 +Gh 16 +Hh 18 +Jh 20 ···(7)

[0108] Figure 3 The diagram illustrates the local optical power variation of the aspherical surfaces obtained by normalizing the position (height) of each aspherical surface using the effective radius in the projection optical system PO1 of Example 1. Figure 3 The vertical axis shows the values ​​obtained by normalizing the position (height) of each aspherical surface using the effective radius. Additionally, Figure 3 The horizontal axis numbering indicates the aspherical surface numbers arranged in the order of the optical path, starting from object surface OP. For the local optical power of the aspherical surface shown on the horizontal axis, the direction to the right of the paper indicates the positive direction, and the direction to the left of the paper indicates the negative direction. Furthermore, Figure 3 The vertical and horizontal axes will be discussed later. Figure 6 , Figure 9 , Figure 12 , Figure 15 , Figure 18 , Figure 21 , Figure 24 The same applies to China.

[0109] exist Figure 3 In the horizontal axis, the first aspherical surface is the aspherical surface of the first aspherical lens L1, and the second aspherical surface is the aspherical surface of the concave mirror M1. These aspherical surfaces are mainly used to correct image plane curvature, astigmatism, and telecentrism that depend on the height of the principal ray. Additionally, the third aspherical surface is the aspherical surface L2R1 of lens L2, and the fourth aspherical surface is the aspherical surface L3R2 of lens L3, corresponding to surfaces 7 and 10 in Table 5, respectively. Furthermore, the projection optical system PO1 of this embodiment 1 is a symmetrical system, so the aspherical surfaces in the optical path from the object plane OP to the convex mirror M2 are described here. The aspherical surfaces in the optical path from the convex mirror M2 to the image plane IP, which have the same tendency, are omitted from the description.

[0110] exist Figure 3 In the diagram, the positions Pcr and Psm of aspherical surface L2R1 are marked with × and 〇 respectively in the third aspherical surface. Similarly, the positions of the rays passing through positions Pcr and Psm of aspherical surface L2R1 and incident on aspherical surface L3R2 are also marked with × and 〇 in the fourth aspherical surface. For example... Figure 3 As shown, in the third aspherical surface L2R1 (surface 7 in Table 5), from position Pcr (× mark) towards position Psm (〇 mark), the local optical power of the aspherical surface increases from... Towards The optical power changes monotonically in the negative direction, satisfying the conditions of equation (1) or (4) above. On the other hand, in the fourth aspherical surface L3R2 (surface 10 in Table 5), the local optical power of the aspherical surface changes monotonically in the positive direction from the × mark toward the ○ mark, in a way that compensates for the change in optical power of the third aspherical surface L2R1. Thus, the effect of aberration correction is maximized, achieving high standardization. In addition, the maximum effective diameter is 1550 mm for the concave mirror M1, so miniaturization is also possible.

[0111] Figure 4A This diagram shows the longitudinal aberration in the projection optical system PO1 of Embodiment 1. Figure 4B This shows the transverse aberration diagram and the wavefront aberration RMS along the i-line. If compared with... Figures 29A-29B The aberration diagram and wavefront aberration RMS comparison of the conventional projection optics system POC are clearly shown, demonstrating that for the illuminated area on the object surface, both meridional and sagittal aberrations, including chromatic aberration, are well corrected. Furthermore, the wavefront aberration RMS at the i-line (365nm) exhibits excellent performance with a maximum of only 13.9 mλ.

[0112] Table 4

[0113]

[0114] Table 5

[0115] Table 6

[0116]

[0117] Face number E F G H J 2 1.017826E-32 1.093147E-38 -6.397746E-44 8.941586E-50 -4.417270E-56 6 -8.417264E-36 2.338933E-41 -3.854523E-47 3.442850E-53 -1.281714E-59 7 -1.161473E-28 2.293436E-33 2.401524E-38 -1.720874E-42 2.026788E-47 10 4.390868E-27 -3.116144E-31 1.524636E-35 -4.638385E-40 6.385601E-45 12 4.390868E-27 -3.116144E-31 1.524636E-35 -4.638385E-40 6.385601E-45 15 -1.161473E-28 2.293436E-33 2.401524E-38 -1.720874E-42 2.026788E-47 16 -8.417264E-36 2.338933E-41 -3.854523E-47 3.442850E-53 -1.281714E-59 20 1.017826E-32 1.093147E-38 -6.397746E-44 8.941586E-50 -4.417270E-56

[0118] Table 7

[0119] (φsm-φcr) / |φoal -0.173 φmr / φtm -0.002 |φAMI / φTL 0.146 Rt / Rm1 0.282 Rt / Rm2 -0.173 2θ 31.9°

[0120] [Example 2]

[0121] Example 2 of the projection optical system according to the present invention will be described. Example 2 basically inherits the content described in Example 1, except for the parts mentioned below, as described in Example 1. For example, the configuration conditions, various definitions, etc. shown in equations (1) to (6) are as described in Example 1.

[0122] Figure 5This is a schematic diagram illustrating the structure of the projection optical system PO2 according to Embodiment 2 of the present invention. The projection optical system PO2 of Embodiment 2 differs from the projection optical system PO1 of Embodiment 1 in the structure of the lens group LG, but otherwise shares the same structure. The lens group LG of Embodiment 2 may include lens L2 and lens L3. Lens L2 can also be understood as a first lens having a first aspherical surface, and lens L3 as a second lens disposed between lens L2 (the first lens) and convex mirror M2 and having a second aspherical surface. In Embodiment 2, lens L2 is a meniscus lens with its convex surface facing the concave mirror side, and the concave mirror side of lens L2 is an aspherical surface (first aspherical surface). Similarly, the concave mirror side of lens L3 is an aspherical surface (second aspherical surface). This differs from Embodiment 1, where the convex mirror side of lens L3 is aspherical, in Embodiment 2, the concave mirror side of lens L3 is aspherical.

[0123] Table 8 below shows the optical specifications of the projection optical system PO2 in this embodiment 2, and also records... Figure 2A The elements shown are as follows. The projection optical system PO2 of this embodiment 2 has an NA of 0.1, but achieves a large screen with an illumination width of 1100 mm and a slit width of 100 mm, which can improve production efficiency. In addition, Tables 9 and 10 below show numerical examples of various parameters in the projection optical system PO2 of this embodiment 2. The explanation of the tables and the aspherical form are the same as in embodiment 1. The projection optical system PO2 of embodiment 2 thus constructed is shown in Table 11 below. All of the above construction conditions of equations (1) to (6) are satisfied except for the construction condition of equation (5). The reason for not satisfying the construction condition of equation (5) is that the main countermeasure is based on the anti-reflection film for ghosting and glare.

[0124] Figure 6 This illustrates the local optical power variation of the aspherical surfaces obtained by normalizing the position (height) of each aspherical surface using the effective radius in the projection optical system PO2 of Example 2. Figure 6 In the horizontal axis, the first aspherical surface is the aspherical surface of the first aspherical lens L1, and the second aspherical surface is the aspherical surface of the concave mirror M1. These aspherical surfaces are mainly used to correct image plane curvature, astigmatism, and telecentrism that depend on the height of the principal ray. Additionally, the third aspherical surface is the aspherical surface on the concave mirror side of lens L2, and the fourth aspherical surface is the aspherical surface on the concave mirror side of lens L3, corresponding to surfaces 7 and 9 in Table 9, respectively. Furthermore, the projection optical system PO2 of this embodiment 2 is a symmetrical system, so the aspherical surfaces in the optical path from the object plane OP to the convex mirror M2 are described here. The aspherical surfaces in the optical path from the convex mirror M2 to the image plane IP, which have the same tendency, are omitted from the description.

[0125] like Figure 6As shown, in the third aspherical surface (surface 7 in Table 9), from position Pcr (× mark) towards position Psm (〇 mark), the local optical power of the aspherical surface increases from... Towards The optical power of the aspherical surface changes monotonically in the negative direction, satisfying the conditions of equation (1) or (4) above. On the other hand, in the fourth aspherical surface (surface 9 in Table 9), the local optical power of the aspherical surface changes monotonically in the positive direction from the × mark toward the ○ mark, in a way that compensates for the change in optical power of the third aspherical surface. Thus, the effect of aberration correction is maximized, achieving high standardization. In addition, the maximum effective diameter is 1550 mm for the concave mirror M1, so miniaturization is also possible.

[0126] Figure 7A This diagram shows the longitudinal aberration in the projection optical system PO2 of Embodiment 2. Figure 7B This shows the transverse aberration diagram and the wavefront aberration RMS along the i-line. If compared with... Figures 29A-29B The aberration diagram and wavefront aberration RMS comparison of the conventional projection optics system POC are clearly shown, demonstrating that for the illuminated area on the object surface, both meridional and sagittal aberrations, including chromatic aberration, are well corrected. Furthermore, the wavefront aberration RMS at the i-line (365nm) exhibits excellent performance with a maximum of only 5.6mλ.

[0127] Table 8

[0128]

[0129] Table 9

[0130] Table 10

[0131]

[0132] Face number E F G H J 1.173558E-32 9.600609E-39 -6.679428E-44 9.559838E-50 -4.763947E-56 6 -4.874270E-36 5.283975E-42 -1.931376E-48 -1.242872E-54 9.924293E-61 7 9.065985E-28 -4.213344E-32 1.157998E-36 -1.774191E-41 1.161745E-46 9 4.009255E-28 2.330439E-33 -1.141178E-36 4.797424E-41 -6.587270E-46 13 4.009255E-28 2.330439E-33 -1.141178E-36 4.797424E-41 -6.587270E-46 15 9.065985E-28 -4.213344E-32 1.157998E-36 -1.774191E-41 1.161745E-46 16 -4.874270E-36 5.283975E-42 -1.931376E-48 -1.242872E-54 9.924293E-61 20 1.173558E-32 9.600609E-39 -6.679428E-44 9.559838E-50 -4.763947E-56

[0133] Table 11

[0134] (φsm-φcr) / |φoa| -0.290 φmr / φtm 0.135 |φAMI / φTL 0.077 Rt / Rm1 1.058 Rt / Rm2 0.569 2θ 34.2°

[0135] [Example 3]

[0136] Example 3 of the projection optical system according to the present invention will be described. Example 3 basically inherits the content described in Example 1, except for the parts mentioned below, as described in Example 1. For example, the configuration conditions, various definitions, etc. shown in formulas (1) to (6) are as described in Example 1.

[0137] Figure 8This is a schematic diagram illustrating the structure of the projection optical system PO3 according to Embodiment 3 of the present invention. The projection optical system PO3 of Embodiment 3 differs from the projection optical system POI of Embodiment 1 in the structure of the lens group LG, but otherwise shares the same structure. The lens group LG of Embodiment 3 may include lens L2, lens L3, and lens L4. It can also be understood that lens L2 is a first lens having a first aspherical surface, and lens L3 and / or lens L4 are second lenses each having a second aspherical surface. In Embodiment 3, lens L2 is a meniscus lens with its convex surface facing the concave mirror side, and the convex mirror side surface of lens L2 is an aspherical surface (first aspherical surface). Furthermore, the concave mirror side surface of lens L3 and / or the convex mirror side surface of lens L4 are respectively aspherical surfaces (second aspherical surfaces).

[0138] Table 12 below shows the optical specifications of the projection optical system PO3 of this embodiment 3, and also records... Figure 2A The elements shown are as follows. The projection optical system PO3 of this embodiment 3 has an NA of 0.1, but achieves a large screen with an illumination width of 1100 mm and a slit width of 100 mm, which can improve production efficiency. In addition, Tables 13 and 14 below show numerical examples of various parameters in the projection optical system PO3 of this embodiment 3. The explanation of the tables and the aspherical formula are the same as in embodiment 1. The projection optical system PO3 of embodiment 3 thus configured is shown in Table 15 below, which satisfies all the configuration conditions of the above formulas (1) to (6).

[0139] Figure 9 This illustrates the local optical power variation of the aspherical surfaces obtained by normalizing the position (height) of each aspherical surface using the effective radius in the projection optical system PO3 of Example 3. Figure 9 In the horizontal axis, the first aspherical surface is the aspherical surface of the first aspherical lens L1, and the second aspherical surface is the aspherical surface of the concave mirror M1. These aspherical surfaces are mainly used to correct image plane curvature, astigmatism, and telecentrism that depend on the height of the principal ray. Additionally, the third aspherical surface is the aspherical surface on the convex mirror side of lens L2, the fourth aspherical surface is the aspherical surface on the concave mirror side of lens L3, and the fifth aspherical surface is the aspherical surface on the convex mirror side of lens L4, corresponding to surfaces 8, 9, and 12 in Table 13, respectively. Furthermore, the projection optical system PO3 of this embodiment 3 is a symmetrical system, so the aspherical surfaces on the optical path from the object plane OP to the convex mirror M2 are described here. The aspherical surfaces on the optical path from the convex mirror M2 to the image plane IP, which have the same tendency, are omitted from the description.

[0140] like Figure 9 As shown, in the third aspherical surface (the 8 surfaces in Table 13), from position Pcr (× mark) towards position Psm (〇 mark), the local optical power of the aspherical surface increases from... Towards The optical power changes monotonically in the negative direction, satisfying the conditions of equation (1) or (4) above. On the other hand, in the fourth aspherical surface (surface 9 in Table 13) and / or the fifth aspherical surface (surface 12 in Table 13), the local optical power of the aspherical surface changes monotonically in the positive direction from the × mark toward the ○ mark, in a manner that compensates for the change in optical power of the third aspherical surface. Thus, the effect of aberration correction is maximized, achieving high standardization. In addition, the maximum effective diameter is 1550 mm for the concave mirror M1, so miniaturization is also possible.

[0141] Figure 10A This shows the longitudinal aberration diagram in the projection optical system PO3 of this embodiment 3. Figure 10B This shows the transverse aberration diagram and the wavefront aberration RMS along the i-line. If compared with... Figures 29A-29B The aberration diagram and wavefront aberration RMS comparison of the conventional projection optics system POC are clearly shown, demonstrating that for the illuminated area on the object surface, both meridional and sagittal aberrations, including chromatic aberration, are well corrected. Furthermore, the wavefront aberration RMS at the i-line (365nm) exhibits excellent performance with a maximum of only 3.5mλ.

[0142] Table 12

[0143]

[0144] Table 13

[0145] Table 14

[0146]

[0147] Face number E F G H J 2 9.771444E-33 1.208860E-38 -6.571308E-44 9.069489E-50 -4.453945E-56 6 -9.271716E-36 1.660133E-41 -1.897520E-47 1.261902E-53 -3.720904E-60 8 -1.649762E-28 -6.399338E-33 2.717073E-37 -4.047570E-42 1.854864E-47 9 -1.222642E-28 -1.449053E-32 5.599273E-37 -7.449154E-42 1.362946E-47 12 1.694930E-27 -1.288145E-31 4.866775E-36 -6.335241E-41 -4.864211E-46 14 1.694930E-27 -1.288145E-31 4.866775E-36 -6.335241E-41 -4.864211E-46 17 -1.222642E-28 -1.449053E-32 5.599273E-37 -7.449154E-42 1.362946E-47 18 -1.649762E-28 -6.399338E-33 2.717073E-37 -4.047570E-42 1.854864E-47 20 -9.271716E-36 1.660133E-41 -1.897520E-47 1.261902E-53 -3.720904E-60 24 9.771444E-33 1.208860E-38 -6.571308E-44 9.069489E-50 -4.453945E-56

[0148] Table 15

[0149] (φsm-φcr / |φ|oa| -0.898 φmr / φtm -0.015 |φAM| / φTL 0.105 Rt / Rm1 0.274 Rt / Rm2 -0.063 2θ 32.9°

[0150] [Example 4]

[0151] Example 4 of the projection optical system according to the present invention will be described. Example 4 basically inherits the content described in Example 1, except for the parts mentioned below, as described in Example 1. For example, the configuration conditions, various definitions, etc. shown in formulas (1) to (6) are as described in Example 1.

[0152] Figure 11This is a schematic diagram illustrating the structure of the projection optical system PO4 according to Embodiment 4 of the present invention. The projection optical system PO4 of Embodiment 4 differs from the projection optical system PO1 of Embodiment 1 in the structure of the lens group LG, but otherwise shares the same structure. The lens group LG of Embodiment 4 may include lens L2, lens L3, and lens L4. It can also be understood that lens L2 and / or lens L3 are first lenses having a first aspherical surface, and lens L4 is a second lens having a second aspherical surface. In Embodiment 4, lens L2 and lens L3 are meniscus lenses with their convex surfaces facing the concave mirror side, and the concave mirror side of lens L2 and / or lens L3 is an aspherical surface (first aspherical surface). Additionally, the convex mirror side of lens L4 is an aspherical surface (second aspherical surface).

[0153] Table 16 below shows the optical specifications of the projection optical system PO4 of this embodiment 4, and also records... Figure 2A The elements shown are as follows. The projection optical system PO4 of this embodiment 4 has an NA of 0.1, but achieves a large screen with an illumination width of 1100 mm and a slit width of 100 mm, which can improve production efficiency. In addition, Tables 17 and 18 below show numerical examples of various parameters in the projection optical system PO4 of this embodiment 4. The explanation of the tables and the aspherical formula are the same as in embodiment 1. The projection optical system PO4 of embodiment 4 thus configured is shown in Table 19 below, which satisfies all the configuration conditions of the above formulas (1) to (6).

[0154] Figure 12 This illustrates the local optical power variation of the aspherical surfaces obtained by normalizing the position (height) of each aspherical surface using the effective radius in the projection optical system PO4 of Example 4. Figure 12 In the horizontal axis, the first aspherical surface is the aspherical surface of the first aspherical lens L1, and the second aspherical surface is the aspherical surface of the concave mirror M1. These aspherical surfaces are mainly used to correct image plane curvature, astigmatism, and telecentrism that depend on the height of the principal ray. Additionally, the third aspherical surface is the concave mirror side of lens L2, the fourth aspherical surface is the concave mirror side of lens L3, and the fifth aspherical surface is the convex mirror side of lens L4, corresponding to surfaces 7, 9, and 12 in Table 17, respectively. Furthermore, the projection optical system PO4 of this embodiment 4 is a symmetrical system, so the aspherical surfaces along the optical path from the object plane OP to the convex mirror M2 are described here. The aspherical surfaces along the optical path from the convex mirror M2 to the image plane IP, which have the same tendency, are omitted from the description.

[0155] like Figure 12 As shown, in the third aspherical surface (surface 7 in Table 17), from position Pcr (× mark) towards position Psm (〇 mark), the local optical power of the aspherical surface increases from... Towards It changes in the negative direction, satisfying the construction conditions of equation (1) or equation (4) above. Furthermore, in the fourth aspherical surface (surface 9 in Table 17), from position Pcr (× mark) towards position Psm (〇 mark), the local optical power of the aspherical surface also changes from... Towards The optical power varies in the negative direction, satisfying the conditions of equation (1) or (4) above. On the other hand, in the fifth aspherical surface (surface 12 in Table 17), the local optical power of the aspherical surface changes monotonically in the positive direction from the × mark toward the ○ mark, in a manner that compensates for the optical power variation of the third and / or fourth aspherical surfaces. Thus, the aberration correction effect is maximized, achieving high standardization. In addition, the maximum effective diameter is 1550 mm for the concave mirror M1, so miniaturization is also possible.

[0156] Figure 13A This diagram shows the longitudinal aberration in the projection optical system PO4 of Embodiment 4. Figure 13B This shows the transverse aberration diagram and the wavefront aberration RMS along the i-line. If compared with... Figures 29A-29B The aberration diagram and wavefront aberration RMS comparison of the conventional projection optics system POC are clearly shown, demonstrating that for the illuminated area on the object surface, both meridional and sagittal aberrations, including chromatic aberration, are well corrected. Furthermore, the wavefront aberration RMS at the i-line (365nm) exhibits excellent performance with a maximum of only 4.3 mλ.

[0157] Table 16

[0158]

[0159] Table 17

[0160] Table 18

[0161]

[0162] Face number E F G H J 9.337967E-33 1.317364E-38 -6.454580E-44 8.559468E-50 -4.064646E-56 6 -5.676325E-36 8.999794E-42 -8.587763E-48 4.356264E-54 -8.216223E-61 7 1.410794E-30 2.954799E-35 -2.112513E-38 6.438387E-43 -6.465439E-48 9 -3.429284E-28 1.376864E-32 -2.610483E-37 7.447634E-43 3.291063E-47 12 -4.507146E-28 1.393062E-31 -1.302094E-35 5.533489E-40 -9.022260E-45 14 -4.507146E-28 1.393062E-31 -1.302094E-35 5.533489E-40 -9.022260E-45 17 -3.429284E-28 1.376864E-32 -2.610483E-37 7.447634E-43 3.291063E-47 19 1.410794E-30 2.954799E-35 -2.112513E-38 6.438387E-43 -6.465439E-48 20 -5.676325E-36 8.999794E-42 -8.587763E-48 4.356264E-54 -8.216223E-61 24 9.337967E-33 1.317364E-38 -6.454580E-44 8.559468E-50 -4.064646E-56

[0163] Table 19

[0164] (φsm-cr) / |φoa|7 sides -0.090 (φsm-φcr) / |φoa|9 sides -0.060 φmr / φtm -0.010 |φAM| / φTL 0.128 Rt / Rm1 0.297 Rt / Rm2 -0.040 2θ 33.2°

[0165] [Example 5]

[0166] Embodiment 5 of the projection optical system according to the present invention will be described. Embodiment 5 basically inherits the content described in Embodiment 1, except for the parts mentioned below, as described in Embodiment 1. For example, the configuration conditions, various definitions, etc. shown in equations (1) to (6) are as described in Embodiment 1.

[0167] Figure 14 This is a schematic diagram illustrating the structure of the projection optical system PO5 according to Embodiment 5 of the present invention. The projection optical system PO5 of Embodiment 5 differs from the projection optical system PO1 of Embodiment 1 in the structure of the lens group LG, but otherwise shares the same structure. The lens group LG of Embodiment 5 may include lens L2 and lens L3. It can also be understood that lens L2 is a first lens having a first aspherical surface, and lens L3 is a second lens having a second aspherical surface. In Embodiment 5, lens L2 is a meniscus lens with its convex surface facing the concave mirror side, and the concave mirror side of lens L2 is an aspherical surface (first aspherical surface). Furthermore, the concave mirror side of lens L3 is an aspherical surface (second aspherical surface).

[0168] Table 20 below shows the optical specifications of the projection optical system PO5 of this embodiment 5, and also records... Figure 2A The elements shown are as follows. Compared with Examples 1 to 4, the projection optical system PO5 of this embodiment 5 has a shorter wavelength, with the main wavelength being the DUV (deep ultraviolet) wavelength of 320nm, and the NA is also large to 0.12. In addition, the illumination width is 900mm and the slit width is 50mm. By shortening the wavelength, increasing the NA, and increasing the illumination width, specifications that enable high resolution and large screen size are achieved. In addition, Tables 21 and 22 below show numerical examples of various parameters in the projection optical system PO5 of this embodiment 5. The explanation of the tables and the aspherical formula are the same as in Example 1. The projection optical system PO5 of this embodiment 5 is configured as shown in Table 23 below, and all of the configuration conditions of the above equations (1) to (6) are satisfied except for the configuration condition of equation (6).

[0169] Figure 15 This illustrates the local optical power variation of the aspherical surfaces obtained by normalizing the position (height) of each aspherical surface using the effective radius in the projection optical system PO5 of Example 5. Figure 15 In the horizontal axis, the first aspherical surface is the aspherical surface of the first aspherical lens L1, and the second aspherical surface is the aspherical surface of the concave mirror M1. These aspherical surfaces are mainly used to correct image plane curvature, astigmatism, and telecentrism that depend on the height of the principal ray. Additionally, the third aspherical surface is the aspherical surface on the concave mirror side of lens L2, and the fourth aspherical surface is the aspherical surface on the concave mirror side of lens L3, corresponding to surfaces 7 and 9 in Table 21, respectively. Furthermore, the projection optical system PO5 of this embodiment 5 is a symmetrical system, so the aspherical surfaces in the optical path from the object plane OP to the convex mirror M2 will be described here. The aspherical surfaces in the optical path from the convex mirror M2 to the image plane IP, which have the same tendency, will be omitted from the description.

[0170] like Figure 15As shown, in the third aspherical surface (surface 7 in Table 21), from position Pcr (× mark) towards position Psm (〇 mark), the local optical power of the aspherical surface increases from... Towards The optical power of the aspheric surface changes monotonically in the negative direction, satisfying the conditions of equation (1) or (4) above. On the other hand, in the fourth aspheric surface (surface 9 in Table 21), the local optical power of the aspheric surface changes monotonically in the positive direction from the × mark toward the ○ mark, in a manner that compensates for the optical power change of the third aspheric surface. Thus, the effect of aberration correction is maximized, achieving high standardization.

[0171] Figure 16A This diagram shows the longitudinal aberration in the projection optical system PO5 of this embodiment 5. Figure 16B The diagram shows the transverse aberration and the wavefront aberration RMS at a wavelength of 320 nm. It can be seen that for the illumination area on the object surface, despite the shortening of the wavelength, the meridional and sagittal aberrations, along with chromatic aberration, are well corrected. Furthermore, the wavefront aberration RMS at 320 nm exhibits excellent performance with a maximum value of only 29.5 mλ.

[0172] Table 20

[0173]

[0174] Table 21

[0175] Table 22

[0176]

[0177] Face number E F G H J 2 5.391691E-33 3.273977E-38 -1.320148E-43 1.766226E-49 -7.369212E-56 6 -2.587754E-35 6.159632E-41 -8.984567E-47 7.355441E-53 -2.591215E-59 7 -5.512496E-29 2.233700E-33 -5.253588E-38 6.987713E-43 -3.946624E-48 9 -1.213578E-27 6.403126E-32 -2.036902E-36 3.572003E-41 -2.656617E-46 13 -1.213578E-27 6.403126E-32 -2.036902E-36 3.572003E-41 -2.656617E-46 15 -5.512496E-29 2.233700E-33 -5.253588E-38 6.987713E-43 -3.946624E-48 16 -2.587754E-35 6.159632E-41 -8.984567E-47 7.355441E-53 -2.591215E-59 20 5.391691E-33 3.273977E-38 -1.320148E-43 1.766226E-49 -7.369212E-56

[0178] Table 23

[0179] (φsm-φcr) / |φoa| -0.087 φmr / φtm 0.000 |φAM| / φTL 0.905 Rt / Rm1 0.057 Rt / Rm2 0.000 2θ 23.4°

[0180] [Example 6]

[0181] Embodiment 6 of the projection optical system according to the present invention will be described. Embodiment 6 basically inherits the content described in Embodiment 1, except for the parts mentioned below, as described in Embodiment 1. For example, the configuration conditions, various definitions, etc. shown in equations (1) to (6) are as described in Embodiment 1.

[0182] Figure 17This is a schematic diagram illustrating the structure of the projection optical system PO6 according to Embodiment 6 of the present invention. Compared to the projection optical system PO1 of Embodiment 1, the projection optical system PO6 of Embodiment 6 has a second aspherical lens L2 between the first aspherical lens L1 and the refractive optical component SG, and the lens group may include lens L3 and lens L4. It can also be understood that lens L3 is a first lens having a first aspherical surface, and lens L4 is a second lens having a second aspherical surface. In this Embodiment 6, lens L3 is a meniscus lens with its convex surface facing the concave mirror side, and the concave mirror side surface of lens L3 is an aspherical surface (first aspherical surface). Similarly, the concave mirror side surface of lens L4 is an aspherical surface (second aspherical surface).

[0183] Table 24 below shows the optical specifications of the projection optical system PO6 of this embodiment 6, and also records... Figure 2A The elements shown are as follows. The projection optical system PO6 of this embodiment 6, like that of embodiment 5, has a shorter wavelength compared to embodiments 1-4, with the main wavelength becoming the DUV (deep ultraviolet) wavelength, i.e., 320 nm. The NA is 0.15 larger than that of embodiment 5. Furthermore, the illumination width is 900 mm, and the slit width is 50 mm. By shortening the wavelength, increasing the NA, and widening the illumination width, specifications capable of high resolution and large screen size are achieved. Tables 25-26 below show numerical examples of various parameters in the projection optical system PO6 of this embodiment 6. The explanations of the tables and the aspherical formula are the same as in embodiment 1. The projection optical system PO6 of embodiment 6, thus configured, satisfies all the configuration conditions of equations (1) to (6) above, as shown in Table 27 below.

[0184] Figure 18 This illustrates the local optical power variation of the aspherical surfaces obtained by normalizing the position (height) of each aspherical surface using the effective radius in the projection optical system PO6 of Example 6. Figure 18 In the horizontal axis, the first and second aspherical surfaces are the aspherical surfaces of the first aspherical lens L1, the third aspherical surface is the aspherical surface of the second aspherical lens L2, and the fourth aspherical surface is the aspherical surface of the concave mirror M1. These aspherical surfaces are mainly used to correct image plane curvature, astigmatism, and telecentrism that depend on the height of the principal ray. In addition, the fifth aspherical surface is the aspherical surface on the concave mirror side of lens L3, and the sixth aspherical surface is the aspherical surface on the concave mirror side of lens L4, corresponding to surfaces 9 and 11 in Table 25, respectively. Furthermore, the projection optical system PO6 of this embodiment 6 is a symmetrical system, so the aspherical surfaces on the optical path from the object plane OP to the convex mirror M2 will be described here, while the aspherical surfaces on the optical path from the convex mirror M2 to the image plane IP, which have the same tendency, will be omitted from the description.

[0185] like Figure 18As shown, in the 5th aspherical surface (surface 9 in Table 25), from position Pcr (× mark) towards position Psm (〇 mark), the local optical power of the aspherical surface increases from... Towards The optical power changes monotonically in the negative direction, satisfying the conditions of equation (1) or (4) above. On the other hand, in the sixth aspherical surface (surface 11 in Table 25), the local optical power of the aspherical surface changes monotonically in the positive direction from the × mark toward the ○ mark, in a way that compensates for the change in optical power of the fifth aspherical surface. Thus, the effect of aberration correction is maximized, achieving high standardization. In addition, the maximum effective diameter is 1524 mm for the concave mirror M1, so high NA (NA0.15) and miniaturization can also be achieved.

[0186] Figure 19A This diagram shows the longitudinal aberration in the projection optical system PO6 of Embodiment 6. Figure 19B The diagram shows the transverse aberration and the wavefront aberration RMS at a wavelength of 320 nm. It can be seen that for the illumination area on the object surface, despite the shortening of the wavelength, the meridional and sagittal aberrations, along with chromatic aberration, are well corrected. Furthermore, the wavefront aberration RMS at 320 nm exhibits excellent performance with a maximum value of only 10.7 mλ.

[0187] Table 24

[0188]

[0189] Table 25

[0190] Table 26

[0191]

[0192] Face number E F G H J 2 1.339681E-32 1.047235E-38 -1.062414E-43 -3.771396E-49 1.130666E-54 3 -4.425417E-32 3.034079E-38 4.018249E-43 -1.102453E-48 1.244879E-54 4 2.337873E-32 8.726999E-38 -1.890603E-43 -2.622537E-50 3.635843E-55 8 -2.126566E-35 2.860744E-41 -1.901062E-47 1.519073E-54 3.414661E-60 9 -1.306650E-28 4.208721E-33 -7.836349E-38 7.967668E-43 -3.379379E-48 11 -2.954051E-27 1.482699E-31 -4.488597E-36 7.499708E-41 -5.308882E-46 15 -2.954051E-27 1.482699E-31 -4.488597E-36 7.499708E-41 -5.308882E-46 17 -1.306650E-28 4.208721E-33 -7.836349E-38 7.967668E-43 -3.379379E-48 18 -2.126566E-35 2.860744E-41 -1.901062E-47 1.519073E-54 3.414661E-60 22 2.337873E-32 8.726999E-38 -1.890603E-43 -2.622537E-50 3.635843E-55 23 -4.425417E-32 3.034079E-38 4.018249E-43 -1.102453E-48 1.244879E-54 24 1.339681E-32 1.047235E-38 -1.062414E-43 -3.771396E-49 1.130666E-54

[0193] Table 27

[0194] (φsm-φcr) / |φoa| -0.104 φmr / φtm 0.000 |φAM| / φTL 0.076 Rt / Rm1 0.066 Rt / Rm2 0.000 2θ 30.5°

[0195] [Example 7]

[0196] Embodiment 7 of the projection optical system according to the present invention will be described. Embodiment 7 basically inherits the content described in Embodiment 1, except for the parts mentioned below, as described in Embodiment 1. For example, the configuration conditions, various definitions, etc. shown in equations (1) to (6) are as described in Embodiment 1.

[0197] Figure 20This is a schematic diagram illustrating the structure of the projection optical system PO7 according to Embodiment 7 of the present invention. The projection optical system PO7 of this Embodiment 7 is an amplification system that magnifies and projects the image of the illumination region IR (specifically, the image of the pattern disposed in the illumination region IR) in the object surface OP onto the image surface IP. Figure 20 In the example, L1 represents the first aspherical lens, L2 represents the second aspherical lens, M1 represents the first concave mirror, LG represents the lens group, M2 represents the convex mirror, M3 represents the second concave mirror, L5 represents the third aspherical lens, and L6 represents the fourth aspherical lens. OA is the optical axis, OP is the object plane, and IP is the image plane. The light beam emitted from the object plane OP at NA0.12 passes through or is reflected in each optical element in the optical path sequence from the object plane OP (L1→L2→M1→LG→M2→LG→M3→L5→L6) and is magnified (by 1.2 times) in the image plane IP to form an image. Alternatively, the pupil position (pupil plane) of the projection optical system PO7 can be the convex mirror M2, and an aperture stop can be placed near the convex mirror M2.

[0198] Furthermore, the lens group LG in this embodiment 7 may include lens L3 and lens L4. It can also be understood that lens L3 is a first lens having a first aspherical surface, and lens L4 is a second lens having a second aspherical surface. In this embodiment 7, lens L3 is a meniscus lens with its convex surface facing the concave mirror side, and the concave mirror side of lens L3 is an aspherical surface (first aspherical surface). Similarly, the concave mirror side of lens L4 is an aspherical surface (second aspherical surface).

[0199] Table 28 below shows the optical specifications of the projection optical system PO7 of this embodiment 7, and also records... Figure 2A The elements shown are as follows. In the projection optical system PO7 of this embodiment 7, the dominant wavelength is set to 365.5 nm and the NA is set to 0.1 (image plane side). In addition, the illumination width is 875 mm and the slit width is 67 mm, but the illumination width is 1050 mm and the slit width is 80 mm after conversion in the image plane. In such a magnification system structure (i.e., a structure with magnification), the illumination width can be increased to achieve a large screen, and the size of the original plate disposed on the object plane OP can be reduced. That is, it has the advantage of being able to produce the original plate inexpensively. In addition, Tables 29 to 30 below show numerical examples of various parameters in the projection optical system PO7 of this embodiment 7. The explanation of the tables and the aspherical formula are the same as in embodiment 1. The projection optical system PO7 of embodiment 7 thus configured is shown in Table 31 below, and all of the configuration conditions of the above equations (1) to (6) are satisfied except for the configuration condition of equation (6).

[0200] Figure 21This illustrates the local optical power variation of the aspherical surfaces obtained by normalizing the position (height) of each aspherical surface using the effective radius in the projection optical system PO7 of Example 7. Figure 21 In the horizontal axis, the first aspherical surface is the aspherical surface of the first aspherical lens L1, the second aspherical surface is the aspherical surface of the second aspherical lens L2, and the third aspherical surface is the aspherical surface of the first concave mirror M1. The eighth aspherical surface is the aspherical surface of the second concave mirror M3, the ninth aspherical surface is the aspherical surface of the third aspherical lens L5, and the tenth aspherical surface is the aspherical surface of the fourth aspherical lens L6. These aspherical surfaces are mainly used to correct image plane curvature, astigmatism, distortion aberrations, coma, and telecentrism that depend on the height of the principal ray. In addition, the fourth aspherical surface is the concave mirror side of lens L3, and the fifth aspherical surface is the concave mirror side of lens L4, corresponding to surfaces 7 and 9 in Table 29, respectively. Furthermore, the aspherical surfaces on the optical path from the object plane OP to the convex mirror M2 are described here, while the aspherical surfaces on the optical path from the convex mirror M2 to the image plane IP, which have the same tendency, are omitted from the description.

[0201] like Figure 21 As shown, in the fourth aspherical surface (surface 7 in Table 29), from position Pcr (× mark) towards position Psm (〇 mark), the local optical power of the aspherical surface increases from... Towards The optical power of the aspheric surface changes monotonically in the negative direction, satisfying the conditions of equation (1) or (4) above. On the other hand, in the fifth aspheric surface (surface 9 in Table 29), the local optical power of the aspheric surface changes monotonically in the positive direction from the × mark toward the ○ mark, in a manner that compensates for the optical power change of the fourth aspheric surface. Thus, the effect of aberration correction is maximized, achieving high standardization.

[0202] Figure 22A This diagram shows the longitudinal aberration in the projection optical system PO7 of Embodiment 7. Figure 22B The diagram shows the transverse aberration and the wavefront aberration RMS of the i-line (wavelength 365.5 nm). It can be seen that for the illuminated area on the object surface, both meridional and sagittal aberrations, including chromatic aberration, are well corrected. Furthermore, the wavefront aberration RMS of the i-line (wavelength 365.5 nm) exhibits excellent performance with a maximum value of only 19.6 mλ.

[0203] Table 28

[0204]

[0205] Table 29

[0206] Table 30

[0207]

[0208] Face number E F G H J 3 -5.131532E-32 1.813248E-37 9.602816E-44 -7.043625E-49 6.033907E-55 4 -2.677161E-31 4.875469E-37 -1.848699E-43 -5.294672E-49 5.150846E-55 6 -3.673720E-34 7.442259E-40 -9.637140E-46 7.210056E-52 -2.369369E-58 7 3.681995E-28 -1.447142E-32 3.468432E-37 -4.572988E-42 2.562966E-47 9 1.166165E-27 -6.677798E-32 2.240955E-36 -4.013606E-41 2.895533E-46 13 1.166165E-27 -6.677798E-32 2.240955E-36 -4.013606E-41 2.895533E-46 15 3.681995E-28 -1.447142E-32 3.468432E-37 -4.572988E-42 2.562966E-47 16 -2.484037E-34 4.134584E-40 -4.355388E-46 2.629201E-52 -6.924352E-59 18 -1.559042E-31 2.038604E-37 -1.516237E-43 4.532138E-50 3.931944E-57 19 -5.390806E-33 3.837265E-39 -1.392413E-44 6.593086E-51 6.856996E-57

[0209] Table 31

[0210] (φsm-φcr) / φoa| -0.101 φmr / φtm -0.114 |φAM| / φTL 0.538 Rt / Rm1 -0.396 Rt / Rm2 -0.481 2θ 27.8°

[0211] [Example 8]

[0212] Example 8 of the projection optical system according to the present invention will be described. Example 8 basically inherits the content described in Example 1 and Example 7, except for the parts mentioned below, as described in Example 1 and Example 7. For example, the configuration conditions, various definitions, etc. shown in formulas (1) to (6) are as described in Example 1.

[0213] Figure 23 This is a schematic diagram illustrating the structure of the projection optical system PO8 according to Embodiment 8 of the present invention. The projection optical system PO8 of Embodiment 8 differs from the projection optical system PO7 of Embodiment 7 in the structure of the lens group LG, but otherwise shares the same structure. The lens group of Embodiment 8 may include lens L3 and lens L4. It can also be understood that lens L3 is a first lens having a first aspherical surface, and lens L4 is a second lens having a second aspherical surface. In Embodiment 8, lens L3 is a meniscus lens with its convex surface facing the concave mirror side, and both the concave mirror side and / or the convex mirror side of lens L3 are aspherical surfaces (first aspherical surface). Additionally, the concave mirror side of lens L4 is aspherical (second aspherical surface). This differs from Embodiment 7, where only the concave mirror side of lens L3 is aspherical, in Embodiment 8, both the concave mirror side and the convex mirror side of lens L3 are aspherical surfaces.

[0214] Table 32 below shows the optical specifications of the projection optical system PO8 of this embodiment 8, and also records... Figure 2AThe elements shown are as follows. In the projection optical system PO8 of this embodiment 8, the main wavelength is set to 365.5 nm, and the NA is set to 0.1 (image plane side), similar to that of embodiment 7. In addition, the illumination width is 875 mm and the slit width is 67 mm, but the illumination width is 1050 mm and the slit width is 80 mm after conversion in the image plane. In such a magnification system structure (i.e., a structure with magnification), the illumination width can be increased to achieve a larger screen, and the size of the original plate disposed on the object plane OP can be reduced. That is, it has the advantage of being able to produce the original plate inexpensively. In addition, Tables 33 and 34 below show numerical examples of various parameters in the projection optical system PO8 of this embodiment 8. The explanation of the tables and the aspherical formula are the same as in embodiment 1. The projection optical system PO7 of embodiment 7, configured in this way, satisfies all the configuration conditions of the above formulas (1) to (6) as shown in Table 35 below.

[0215] Figure 24 This illustrates the local optical power variation of the aspherical surfaces obtained by normalizing the position (height) of each aspherical surface using the effective radius in the projection optical system PO8 of Example 8. Figure 24 In the horizontal axis, the first aspherical surface is the aspherical surface of the first aspherical lens L1, the second aspherical surface is the aspherical surface of the second aspherical lens L2, and the third aspherical surface is the aspherical surface of the first concave mirror M1. The tenth aspherical surface is the aspherical surface of the second concave mirror M3, the eleventh aspherical surface is the aspherical surface of the third aspherical lens L5, and the twelfth aspherical surface is the aspherical surface of the fourth aspherical lens L6. These aspherical surfaces are mainly used to correct image plane curvature, astigmatism, distortion aberrations, coma, and telecentrism that depend on the height of the principal ray. In addition, the fourth aspherical surface is the concave mirror side of lens L3, the fifth aspherical surface is the convex mirror side of lens L3, and the sixth aspherical surface is the concave mirror side of lens L4, corresponding to surfaces 7, 8, and 9 in Table 33, respectively. Furthermore, the aspherical surfaces on the optical path from the object plane OP to the convex mirror M2 are described here, while the aspherical surfaces on the optical path from the convex mirror M2 to the image plane IP, which have the same tendency, are omitted from the description.

[0216] like Figure 24 As shown, in the fourth aspherical surface (surface 7 in Table 33), from position Pcr (× mark) towards position Psm (〇 mark), the local optical power of the aspherical surface increases from... Towards It changes monotonically in the negative direction, satisfying the conditions for formation of equation (1) or equation (4) above. Furthermore, in the fifth aspherical surface (surface 8 in Table 33), from position Pcr (× mark) towards position Psm (〇 mark), the local optical power of the aspherical surface also changes from... Towards The optical power changes monotonically in the negative direction, satisfying the conditions of equation (1) or (4) above. On the other hand, in the sixth aspherical surface (surface 9 in Table 33), the local optical power of the aspherical surface changes monotonically in the positive direction from the × mark toward the ○ mark, in a way that compensates for the optical power changes of the fourth aspherical surface and / or the fifth aspherical surface. Thus, the aberration correction effect is maximized, achieving high standardization. In addition, the maximum effective diameter is 1658 mm for the second concave mirror M3, so miniaturization is also possible.

[0217] Figure 25A This shows the longitudinal aberration diagram in the projection optical system PO8 of this embodiment 8. Figure 25B The diagram shows the transverse aberration and the wavefront aberration RMS of the i-line (wavelength 365.5 nm). It can be seen that for the illuminated area on the object surface, both meridional and sagittal aberrations, including chromatic aberration, are well corrected. Furthermore, the wavefront aberration RMS of the i-line (wavelength 365.5 nm) exhibits excellent performance with a maximum value of only 17.4 mλ.

[0218] Table 32

[0219]

[0220] Table 33

[0221] Table 34

[0222]

[0223] Face number E F G H J 3 -5.237743E-32 1.813587E-37 1.044574E-43 -6.803619E-49 5.822458E-55 4 -2.684155E-31 4.873676E-37 -1.814542E-43 -5.079205E-49 5.070414E-55 6 -3.627675E-34 7.741442E-40 -1.041868E-45 8.014396E-52 -2.683038E-58 7 2.888130E-28 -1.252113E-32 3.274159E-37 -4.657165E-42 2.757344E-47 8 6.679766E-29 -5.113580E-33 -4.562078E-37 2.544880E-41 -5.258757E-46 9 1.170031E-27 -9.585111E-32 4.164509E-36 -1.013719E-40 8.841499E-46 13 1.170031E-27 -9.585111E-32 4.164509E-36 -1.013719E-40 8.841499E-46 14 6.679766E-29 -5.113580E-33 -4.562078E-37 2.544880E-41 -5.258757E-46 15 2.888130E-28 -1.252113E-32 3.274159E-37 -4.657165E-42 2.757344E-47 16 -2.523772E-34 4.178415E-40 -4.374785E-46 2.624763E-52 -6.871086E-59 18 -1.555925E-31 2.044059E-37 -1.509682E-43 4.507722E-50 -6.253508E-58 19 -5.080839E-33 4.431001E-39 -1.325910E-44 6.321541E-51 2.425272E-57

[0224] Table 35

[0225] (φsm-φcr) / |φoa|7 sides -0.186 (φsm-φcr) / |φoa|8 sides -0.233 φmr / φtm -0.110 |φAM| / φTL 0.132 Rt / Rm1 -0.234 Rt / Rm2 -0.465 2θ 32.6°

[0226] <Implementation Method of Exposure Device>

[0227] An embodiment of an exposure apparatus having the projection optical system involved in this invention is described. Figure 26This is a schematic diagram showing a structural example of the exposure apparatus EA according to this embodiment. The exposure apparatus EA of this embodiment is, for example, a scanning exposure apparatus that transfers the pattern of the original plate 9 onto the substrate 20 while scanning the original plate 9 and the substrate 20 relative to each other. It may include an illumination optical system IL, a projection optical system PO, and a control unit CNT. The control unit CNT is, for example, a computer having a CPU (Central Processing Unit), memory, etc., and controls the exposure of the substrate 20 by controlling each part of the exposure apparatus EA. Furthermore, the original plate 9 and the substrate 20 are held and driven by an original plate driving mechanism (original plate stage) and a substrate driving mechanism (substrate stage), respectively (not shown).

[0228] The illumination optical system IL may include, for example, a light source LS, a first condenser lens 3, an optical integrator 4 (compound eye lens), a second condenser lens 5, a slit defining member 6, an imaging optical system 7, and a plane mirror 8. The light source LS may include, for example, a mercury lamp 1 and an elliptical mirror 2. The slit defining member 6 defines the illumination area of ​​the original image 9 (i.e., the cross-sectional shape of the slit light illuminating the original image 9). The imaging optical system 7 is configured to image the slit light defined by the slit defining member 6 onto the object surface OP of the projection optical system PO. The plane mirror 8 bends the light path in the illumination optical system IL. Furthermore, in... Figure 26 In the exposure apparatus EA shown, the light source LS is set as a constituent element of the illumination optical system IL, but it is not limited to this; the light source LS may not be a constituent element of the illumination optical system IL.

[0229] The projection optical system PO projects the pattern of the original image 9 disposed on the object surface OP onto the substrate 20 disposed on the image surface IP. As a result, the substrate 20 is exposed, and the pattern of the original image 9 can be transferred onto the substrate. The projection optical system PO can be configured as any one of a constant magnification imaging optical system (constant magnification system), a magnifying imaging optical system (magnification system), and a reducing imaging optical system (reducing system). In this embodiment, it can be configured as either a constant magnification imaging optical system or a magnifying imaging optical system. Furthermore, any one of the projection optical systems PO1 to PO8 from the aforementioned embodiments 1 to 8 can be used as the projection optical system PO.

[0230] The projection optical system PO may include, in sequence from the object surface OP to the image surface, a first aspherical lens 10, a first plane mirror 12, a first concave mirror 13, a convex mirror 15, a second concave mirror 16, a second plane mirror 17, and a second aspherical lens 19. Furthermore, a first refractive element 11 may be disposed between the first aspherical lens 10 and the first plane mirror 12, and a second refractive element 18 may be disposed between the second plane mirror 17 and the second aspherical lens 19. The first refractive element 11 and the second refractive element 18 can be used to adjust the imaging magnification and / or distortion aberration. In addition, the projection optical system PO of this embodiment provides a lens group 14 between the concave mirrors (first concave mirror 13, second concave mirror 16) and the convex mirror 15. In the lens group 14, any one of the lens groups LG described in embodiments 1 to 8 can be used. Furthermore, the plane including the mirror surface (reflecting surface) of the first plane mirror 12 and the plane including the mirror surface (reflecting surface) of the second plane mirror 17 can form a 90-degree angle with each other. The first plane mirror 12 and the second plane mirror 17 can also be integrally formed (i.e., as a single structure). In addition, the first concave mirror 13 and the second concave mirror 16 can also be integrally formed (i.e., as a single structure).

[0231] <Implementation Method of Manufacturing the Item>

[0232] The article manufacturing method according to the embodiments of the present invention is suitable for manufacturing articles such as micro-devices like semiconductor devices and components with fine structures. The article manufacturing method of this embodiment includes: a step of forming a latent image pattern in a photosensitive agent coated onto a substrate using the aforementioned exposure apparatus (a step of exposing the substrate); and a step of developing (processing) the substrate after the latent image pattern has been formed in the aforementioned step. Furthermore, the above manufacturing method includes other known steps (oxidation, film formation, vapor deposition, doping, planarization, etching, resist stripping, cutting, bonding, encapsulation, etc.). Compared with conventional methods, the article manufacturing method of this embodiment is more advantageous in at least one aspect of article performance, quality, productivity, and production cost.

[0233] The invention is not limited to the embodiments described above, and various changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, the claims are appended to disclose the scope of the invention.

Claims

1. A projection optical system comprising a concave mirror and a convex mirror, wherein an image of a pattern in an illumination area located outside the optical axis of an object surface is reflected and projected onto an image plane in the order of the concave mirror, the convex mirror, and the concave mirror, wherein the projection optical system is characterized in that, It has a lens group disposed in the optical path between the concave mirror and the convex mirror. The concave mirror is aspherical. The lens group includes a first lens having a first aspherical surface and a second lens having a second aspherical surface, disposed between the first lens and the convex mirror. In the first aspherical surface of the first lens, the endpoint closer to the optical axis among the two endpoints of the line intersecting the meridional plane that bisects the illumination area and the illumination area is designated as Yi, and the endpoint farther from the optical axis is designated as Ya. The position of the principal ray from endpoint Yi on the first aspherical surface is designated as Pcr, and the position of the sagittal edge ray from endpoint Ya on the first aspherical surface is designated as Psm. The optical powers at positions Pcr and Psm are designated as φcr and φsm, respectively, and the optical power along the optical axis in the first aspherical surface is designated as φoa. This satisfies the following conditions: (φsm-φcr) / |φoa|<0, Furthermore, the optical power changes from position Pcr to position Psm, with the optical power changing in a negative direction from the optical power φcr to the optical power φsm. The second aspherical surface of the second lens has a region in the first aspherical surface that is used to compensate for the change in optical power from position Pcr to position Psm, where the optical power changes in a positive direction from the position of light incident through position Pcr of the first aspherical surface toward the position of light incident through position Psm of the first aspherical surface.

2. The projection optical system according to claim 1, characterized in that, When the optical power of the second aspherical surface of the second lens is set to φmr, and the optical power of the convex mirror is set to φtm, the following conditions are met: -0.12≤φmr / φtm≤0.

15.

3. The projection optical system according to claim 1, characterized in that, When the optical power of the entire lens group is set to φAM, and the optical power of the second lens is set to φTL, the following conditions are met: 0.08≤|φAM| / φTL≤0.

95.

4. The projection optical system according to claim 1, characterized in that, The first aspherical surface of the first lens satisfies -0.95≤(φsm-φcr) / |φoa|≤-0.

055.

5. The projection optical system according to claim 1, characterized in that, The first lens is the lens in the lens group that is positioned closest to the concave mirror.

6. The projection optical system according to claim 1, characterized in that, The first lens is a meniscus lens with its convex surface facing the concave mirror side.

7. The projection optical system according to claim 1, characterized in that, The second lens is the lens in the lens group that is positioned closest to the convex mirror.

8. The projection optical system according to claim 1, characterized in that, The optical power of the second lens is positive.

9. The projection optical system according to claim 1, characterized in that, When the radius of curvature of the convex mirror is set to Rt, the radius of curvature of the concave mirror side of the second lens is set to Rm1, and the radius of curvature of the convex mirror side of the second lens is set to Rm2, the following conditions are met: Rt / Rm1≤0.31 and Rt / Rm2≤0.31, At least one of the concave mirror side surface and the convex mirror side surface of the second lens is the second aspherical surface.

10. The projection optical system according to claim 1, characterized in that, The angle at which the principal ray from the height of the largest object enters the lens group from the concave mirror is greater than 30 degrees.

11. The projection optical system according to claim 1, characterized in that, The illuminated area is an arc-shaped area.

12. The projection optical system according to claim 1, characterized in that, An aspherical lens is also provided in the optical path between the object surface and the concave mirror and / or between the image surface and the concave mirror.

13. The projection optical system according to claim 1, characterized in that, The projection optical system is an equal magnification system.

14. The projection optical system according to claim 1, characterized in that, The projection optical system is an amplification system.

15. A projection optical system comprising a concave mirror and a convex mirror, wherein an image of a pattern in an illumination area located outside the optical axis of an object surface is reflected and projected onto an image plane in the order of the concave mirror, the convex mirror, and the concave mirror, wherein the projection optical system is characterized in that... It has a lens group disposed in the optical path between the concave mirror and the convex mirror. The lens group includes a first lens having a first aspherical surface and a second lens having a second aspherical surface, disposed between the first lens and the convex mirror. In the first aspherical surface of the first lens, the endpoint closer to the optical axis among the two endpoints of the line intersecting the meridional plane that bisects the illumination area and the illumination area is designated as Yi, and the endpoint farther from the optical axis is designated as Ya. The position of the first aspherical surface where the principal ray from endpoint Yi is incident is designated as Pcr, and the position of the first aspherical surface where the sagittal edge ray from endpoint Ya is incident is designated as Psm. When the optical power at positions Pcr and Psm is designated as φcr and φsm respectively, the following conditions are met: φsm<φcr, The second aspherical surface of the second lens has a region for compensating for the change in optical power from position Pcr to position Psm in the first aspherical surface. When the radius of curvature of the convex mirror is set to Rt, the radius of curvature of the concave mirror side of the second lens is set to Rm1, and the radius of curvature of the convex mirror side of the second lens is set to Rm2, the following conditions are met: Rt / Rm1≤0.31 and Rt / Rm2≤0.31, At least one of the concave mirror side surface and the convex mirror side surface of the second lens is the second aspherical surface.

16. An exposure apparatus for exposing a substrate, characterized in that, have: An illumination optical system illuminates the original artwork; and The projection optical system according to any one of claims 1 to 15, The projection optics system projects the pattern of the original image disposed on the object surface onto the substrate disposed on the image surface.

17. A method for manufacturing an article, characterized in that, include: The exposure process involves exposing the substrate using the exposure apparatus described in claim 16; as well as The processing step involves processing the substrate after it has been exposed in the exposure step. Articles are manufactured from the substrate processed in the said processing step.

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