Exposure apparatus and manufacturing method thereof, projection optical system design method, and article manufacturing method

Abstract

To provide a technique advantageous for improving performance of an exposure device having a plurality of projection optical systems.SOLUTION: Each of a plurality of projection optical systems includes a first imaging optical system which has a trapezoid exposure region and forms an intermediate image of an original plate, and a second imaging optical system which projects an intermediate image onto a substrate. A numerical aperture NA of the projection optical system is 0.12 or more and 0.65 or less, a distance h2 between a first plane arranged with the original plate and a part perpendicular to the first plane among optical axes of the projection optical system is 10 mm or more and 70 mm or less, a shortest distance d1 between an optical member closest to a fold mirror and the fold mirror among optical member groups arranged between the fold mirror and a concave mirror is 1 mm or more and 20 mm or less, LR that is a radius of the optical member is 100 mm or more and 400 mm or less, a difference between x2 that is 1 / 2 of a length of a lower bottom of a trapezoid and x1 that is 1 / 2 of a length of an upper bottom of the trapezoid is 3 mm or more and 25 mm or less, and x1 is 10 mm or more and 70 mm or less.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an exposure apparatus and a manufacturing method thereof, a method for designing a projection optical system, and a method for manufacturing an article. Regarding. [Background technology]

[0002] An exposure apparatus exposes a substrate by projecting a pattern of an original onto the substrate. As described in Patent Document 1, there is an exposure apparatus that has a plurality of projection optical systems in order to expand an exposure area. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 3724517 Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 does not mention a design that satisfies all five conditions for improving the performance of an exposure apparatus, namely, improving the imaging performance of the projection optical system, satisfying the holding constraints of the projection optical system, ensuring that the lens diameter satisfies manufacturing constraints, suppressing streaky unevenness at the joints between adjacent exposure areas, and increasing the horizontal width of the image area.

[0005] Increasing the width of the image area helps expose a larger area with fewer projection optics. Fewer projection optics reduces the number of seams that can degrade imaging performance. Fewer projection optics also reduces manufacturing costs.

[0006] An object of the present invention is to provide a technique that is advantageous for improving the performance of an exposure apparatus having a plurality of projection optical systems. [Means for solving the problem]

[0007] One aspect of the present invention relates to an exposure apparatus having a plurality of projection optical systems that project an image of an original onto a substrate, wherein in the exposure apparatus, each of the plurality of projection optical systems has a trapezoidal exposure area, and each of the plurality of projection optical systems includes a first imaging optical system that forms an intermediate image of the original, and a second imaging optical system that projects the intermediate image onto the substrate, each of the first imaging optical system and the second imaging optical system: Optical components, Includes a folding mirror and a concave mirror, each of the first imaging optical system and the second imaging optical system transmits or reflects an incident light beam through the bending mirror, the optical member, the concave mirror, the optical member, and the bending mirror in this order; The numerical aperture (NA) of the projection optical system is 0.12 or more and 0.65 or less. 、 Among the optical members arranged between the bending mirror and the concave mirror, the optical member closest to the bending mirror The above The shortest distance d1 between the optical member and the folding mirror is 1 mm or more and 20 mm or less, and the radius LR of the optical member is 100 mm or more and 400 mm or less, a difference h2 between a distance h1 between a first surface on which the original is disposed and the optical axis of the concave mirror and a radius LR of the optical member is 10 mm or more and 70 mm or less; The difference (x2-x1) between x2, which is 1 / 2 the length of the lower base of the trapezoid, and x1, which is 1 / 2 the length of the upper base of the trapezoid, is 3 mm or more and 25 mm or less, and x1 is 10 mm or more and 70 mm or less. Effect of the Invention

[0008] According to the present invention, a technique is provided that is advantageous for improving the performance of an exposure apparatus having a plurality of projection optical systems. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing the arrangement of an exposure apparatus according to an embodiment. [Diagram 2] 2 is a diagram showing the configuration of each of a plurality of projection optical systems that make up the projection system in FIG. 1; [Diagram 3] FIG. [Figure 4] 3 is a diagram showing design parameters of the projection optical system or the first imaging optical system in FIG. 2; [Diagram 5] A graph showing the results of solving a system of simultaneous equations that meets five conditions. [Figure 6] FIG. 1 is a diagram showing an imaging optical system according to a first embodiment. [Figure 7]4A to 4C are diagrams including aberration diagrams of the first embodiment. [Figure 8] FIG. 13 is a graph showing the results of solving simultaneous equations that satisfy five conditions by changing the NA in the first embodiment from 0.15 to 0.23. [Figure 9] FIG. 11 is a graph showing the results of solving simultaneous equations with NA=0.14 in the second embodiment. [Figure 10] FIG. 11 is a diagram showing an imaging optical system according to a second embodiment. [Figure 11] 11A to 11C are diagrams including aberration diagrams of Example 2. [Figure 12] FIG. 13 is a graph showing the results of solving simultaneous equations with NA=0.125 in the second embodiment. [Figure 13] FIG. 11 is a diagram showing an imaging optical system according to a third embodiment. [Figure 14] 13A to 13C are diagrams showing aberrations in the third embodiment. [Figure 15] FIG. 13 is a diagram showing a design method according to a fifth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0011] FIG. 1 shows the configuration of an exposure apparatus 1 according to an embodiment. The exposure apparatus 1 may include a projection system 10 that projects a pattern of an original 11 onto a substrate 12. The projection system 10 may include a plurality of projection optical systems 101. Each projection optical system 101 projects an image of (the pattern of) the original 11 onto the substrate 12. The image projected onto the substrate 12 by the projection optical system 101 is an erect image. Each projection optical system 101 may have an image area 102 in a plane including an image plane. The image area 102 is an area irradiated with light by one projection optical system 101, that is, an exposure area. The image area 102 may have a trapezoidal shape. In other words, each of the plurality of projection optical systems that constitute the projection system 10 has a trapezoidal exposure area. The exposure apparatus 1 may be configured as a scanning exposure apparatus that performs scanning exposure to expose the substrate 12 while scanning the original 11 and the substrate 12. Although not shown, the exposure apparatus 1 may include an illumination system that illuminates the original 11. The number of projection optical systems 101 constituting the projection system 10 can be determined arbitrarily. The number of projection optical systems 101 constituting the projection system 10 is, for example, six or more.

[0012] A method for designing a projection optical system that satisfies five conditions, namely, improving the imaging performance of each projection optical system, satisfying the holding constraints of the projection optical system, satisfying the manufacturing constraints for the lens diameter, suppressing stripe-like unevenness at the joints between adjacent exposure areas, and increasing the horizontal width of the image area, will be described below. This design method may be understood as being part of a manufacturing method for manufacturing an exposure apparatus. The manufacturing method for the exposure apparatus may include a step of designing a projection optical system according to the design method described below, a step of manufacturing a plurality of projection optical systems according to the design by this step, and a step of assembling an exposure apparatus having the plurality of projection optical systems.

[0013] In order to improve the imaging performance of the projection optical system 101, the NA (numerical aperture) of the projection optical system 101 should be set to a certain value or more. In order to satisfy the holding constraints of the projection optical system 101, the value of a shape parameter related to the holding constraints should be specified. In order for the diameter (lens diameter) of the lens constituting the projection optical system 101 to satisfy the manufacturing constraints, the value of a parameter corresponding to the lens diameter should be specified. In order to suppress streaky unevenness at the joint, the value of a shape parameter related to the streaky unevenness should be specified. In order to increase the lateral width of the image area, the value of a shape parameter related to the size of the image area should be specified. There is no document that presents a specific conditional formula that simultaneously satisfies these five conditions. In this embodiment, the conditional formula that simultaneously satisfies the above five conditions is formulated as a simultaneous equation, and by obtaining a design solution that satisfies this conditional formula, it is possible to provide an exposure apparatus that simultaneously satisfies the above five conditions.

[0014] 2 shows an example configuration of each projection optical system 101 constituting the projection system 10. The projection optical system 101 can include a first imaging optical system 1011 that forms an intermediate image im of the original 11, and a second imaging optical system 1012 that projects the intermediate image im onto the substrate 12. The object plane of the first imaging optical system 1011 coincides with the object plane of the projection optical system 101, and the image plane of the first imaging optical system 1011 is a plane on which the intermediate image im is formed and coincides with the object plane of the second imaging optical system 1012. The image plane of the second imaging optical system 1012 coincides with the image plane of the projection optical system 101.

[0015] The first imaging optical system 1011 may be an optical system including a folding mirror M1 having a first reflecting surface m11 and a second reflecting surface m12, and a concave mirror m13. The second imaging optical system 1012 may be an optical system including a folding mirror M2 having a first reflecting surface m21 and a second reflecting surface m22, and a concave mirror n13. In another aspect, the first imaging optical system 1011 and the second imaging optical system 1012 may be Dyson optical systems. The first reflecting surface m11 and the second reflecting surface m12 constituting the folding mirror M1 of the first imaging optical system 1011 may be composed of integrated optical components, or may be composed of optical components separated from each other. The first reflecting surface m21 and the second reflecting surface m22 constituting the folding mirror M2 of the second imaging optical system 1012 may be composed of integrated optical components, or may be composed of optical components separated from each other.

[0016] The first imaging optical system 1011 and the second imaging optical system 1012 may be configured as optical systems having the same configuration, or may be configured as optical systems having different configurations. The first imaging optical system 1011 may include optical members (lenses) H and I on the optical path of the first imaging optical system 1011, and may have a function of correcting the focus, distortion, and field curvature of the first imaging optical system 1011 by driving (translation movement, rotation) the optical members H and I. The second imaging optical system 1012 may include optical members (lenses) J and K on the optical path of the second imaging optical system 1012, and may have a function of correcting the focus, distortion, and field curvature of the second imaging optical system 1012 by driving (translation movement, rotation) the optical members J and K. Here, the optical members H and I may have the same configuration, or may have different configurations. In addition, the optical members J and K may have the same configuration, or may have different configurations. For example, when the optical member H and the optical member J have different configurations, the first imaging optical system 1011 and the second imaging optical system 1012 have different configurations. Similarly, when the optical member I and the optical member K have different configurations, the first imaging optical system 1011 and the second imaging optical system 1012 have different configurations.

[0017] Each of the multiple projection optical systems 101 constituting the projection system 10 projects an upright image of the original 11 (its pattern) onto the substrate 12, and the image areas 102 of the multiple projection optical systems 101 can be connected together through scanning exposure. This makes it possible to expose a wide area of ​​the substrate 12.

[0018] FIG. 3 illustrates an image area 102 of one projection optical system 101, its circumscribing circle, and parameters required for formulation. The shape of the image area 102 is a trapezoid, and half the length of the upper base of the trapezoid is defined as x1, half the length of the lower base is defined as x2, and the distance between the upper and lower bases is defined as y1. The angle of the hypotenuse of the trapezoid is defined as θd. The radius of the circumscribing circle of the image area 102 is defined as R. Note that R is different from the lens radius LR described later. Furthermore, the distance between the center of the circumscribing circle and the lower base of the image area 102 is defined as y0. All of these parameters are useful for formulation. In particular, taking y0 into consideration greatly contributes to facilitating the design of the projection optical system 101.

[0019] FIG. 4 illustrates the first imaging optical system 1011 and parameters used in the formulation. The original surface 21 is the surface (first surface) on which the original 11 is placed. The intermediate image surface 25 is the surface on which the intermediate im is formed. The second imaging optical system 1012 may have a configuration in which the original surface 21 is replaced with an intermediate image surface, and the intermediate image surface 25 is replaced with an image surface on which the substrate 12 is placed. The part of the optical axis of the first imaging optical system 1011 that is perpendicular to the original surface 21 (the part between the folding mirror M1 and the concave mirror m13) is shown as the optical axis 23. The distances corresponding to y0 and y1 shown in FIG. 3 are also shown in FIG. 4.

[0020] The distance between the original surface (first surface) 21 and the optical axis 23 is defined as h1. Furthermore, the shortest distance between the bending mirror M1 and the optical member OM that is closest to the bending mirror M1 among the group of optical members arranged between the bending mirror M1 and the concave mirror m13 is defined as d1. Furthermore, the radius (lens radius) of the optical member OM is defined as LR. Furthermore, it is defined as h2=h1-LR. In this embodiment, simultaneous equations are formulated to obtain a design solution for the projection system 10 or the projection optical system 101 that constitutes it, using the parameters shown in FIG. 3 and the parameters shown in FIG. 4.

[0021] The numerical aperture, NA, of the projection optical system 101 is expressed as in equation (1).

[0022] NA = n × sinΘ Equation (1) Here, n is the refractive index, and in this example, n = 1. Regarding Θ in equation (1), equation (2) can be obtained from FIG.

[0023] tanΘ=y0 / h1 Equation (2) If the sine condition is taken into account, sinΘ=y0 / h1 may be used. In the following example, equation (2) is used.

[0024] Equation (3) can be obtained from Figure 3 using the Pythagorean theorem.

[0025] (y0+y1) 2 +(x1) 2 =R 2 ...Equation (3) From FIG. 4, the lens radius LR can be approximated by the position of the light ray passing through the outermost part of the lens (optical member OM) to obtain equation (4).

[0026] LR=R+(h1+d1)×tanΘ...Equation (4) Furthermore, equation (5) holds true from the above definition.

[0027] h1=h2+LR...Equation (5) Substituting equation (5) into equation (4) and rearranging, we obtain equation (6).

[0028] LR = R + (h2 + LR + d1) × tan Θ LR={R+(h2+d1)tanΘ} / (1-tanΘ)...Equation (6) Furthermore, by substituting equation (2) into equation (6) and rearranging, we obtain equation (7).

[0029] LR={R+(h2+d1)×y0 / h1} / (1-y0 / h1)...Equation (7) Equations (3) and (7) are the simultaneous equations proposed in this embodiment.

[0030] The projection optical system 101 can be designed and manufactured by solving the simultaneous equations given by equations (3) and (7) in accordance with the above five conditions. Here, the projection optical system can be designed to satisfy the simultaneous equations given by equations (3) and (7) for at least two NAs.

[0031] A method for designing a projection optical system in one embodiment may include a step of determining the configuration of the projection optical system 101 by setting NA to a value of 0.12 or more, h2 to a first predetermined value or more, d1 to a second predetermined value or more, LR to a third predetermined value or less, 2(x2-x1) to a fourth predetermined value or more, and 2·x1 to a fifth predetermined value or more.

[0032] Several examples will now be described. EXAMPLES

[0033] Example 1 of this embodiment will be described below.

[0034] The first condition (J1), ie, the NA which is a condition for improving the imaging performance of the projection optical system 101, is set to, for example, 0.15, which is a numerical value within a range of 0.12 or more (eg, a range of 0.12 or more and 0.65 or less).

[0035] As the second condition (J2), that is, the condition for satisfying the holding constraint of the projection optical system 101, d1 shown in Fig. 4 is set to, for example, 15.0 mm within a range of 1 mm to 20 mm so as to be a realizable value (for example, 1 mm) or more. Also, h2 shown in Fig. 4 is set to, for example, 64.8 mm within a range of 10 mm to 70 mm so as to be a realizable value, for example, 10 mm or more.

[0036] As the third condition (J3), i.e., the condition that the lens diameter satisfies the manufacturing constraints, LR shown in FIG. 4 is set to a feasible value or less (e.g., 400 mm or less), for example, 125.2 mm within the range of 100 mm or more and 400 mm or less.

[0037] As the fourth condition (J4), that is, the condition for suppressing stripe-like unevenness at the joint, (x2-x1) shown in FIG. 3 is set to be equal to or greater than the limit value required by the specifications (for example, 3 mm or more), for example, 20.8 mm within the range of 3 mm or more and 25 mm or less. Here, (x2-x1) is set to be equal to or greater than the desired value because it is known that stripe-like unevenness is likely to occur at the joint when (x2-x1) is less than the limit value, particularly when (x2-x1) is zero. Note that when (x2-x1) is zero, the direction of the boundary line of the joint becomes the same as the scanning direction of the substrate, and in this case, stripe-like unevenness may become very large. By setting (x2-x1) to be equal to or greater than the limit value, the angle between the direction of the boundary line of the joint and the scanning direction of the substrate can be increased, and stripe-like unevenness at the joint can be suppressed. As a condition for suppressing stripe-like unevenness at the joint, it is desirable that the angle θd of the oblique side of the trapezoid in FIG. 3 is equal to or greater than 45 degrees and equal to or less than 80 degrees.

[0038] As a fifth condition (J5), i.e., a condition for increasing the lateral width of the image area, x1 shown in FIG. 3 is set to be equal to or greater than a limit value (e.g., equal to or greater than 10 mm), for example, 68.2 mm within the range of 10 mm or more and 70 mm or less.

[0039] The range of x1 and y0 in FIG. 3 that satisfies these conditions is shown in FIG. 5. Conditions J3, J4, and J5 are shown in FIG. 5. The region of x1 and y0 shown in intermediate colors in FIG. 5 satisfies all of the first to fifth conditions (J1 to J5). In the projection optical system of Example 1 shown as "design solution" in FIG. 5, y0=29 mm and R=93.5 mm.

[0040] The configuration of the projection optical system 101 constituting the projection system 10 of the first embodiment will be described below with reference to Fig. 6. Here, the projection optical system 101 is composed of a first imaging optical system 1011 and a second imaging optical system 1012, and the second imaging optical system 1012 has the same configuration as the first imaging optical system 1011.

[0041] The projection optical system 101 constituting the projection system 10 of the first embodiment has NA=0.15, and chromatic aberration is corrected for all of the i-line (365.5 nm), h-line (405.5 nm), and g-line (435.5 nm) that can be used as exposure light. The projection optical system 101 of the first embodiment is a symmetrical optical system with a life-size that is telecentric in the object field and the image field. Therefore, the projection optical system 101 of the first embodiment has the characteristic that coma aberration, distortion aberration, and chromatic aberration of magnification do not occur in principle.

[0042] The first imaging optical system 1011 is configured by disposing, in order from the original surface 21, a parallel plate H, a prism or plane mirror P having a reflecting surface tilted at 45 degrees with respect to the optical axis 23, a positive lens group Gp, a negative lens group Gn, and a concave mirror Mn between the original surface 21 and the concave mirror Mn. The plane mirror P is the folding mirror described above. The positive lens group Gp is ​​disposed between the plane mirror P (folding mirror) and the concave mirror Mn, and the negative lens group Gn is disposed between the positive lens group Gp and the concave mirror Mn. Light from the original 11 travels toward the substrate 12 via a first reflecting surface of the plane mirror P (folding mirror), the positive lens group Gp, the negative lens group Gn, the concave mirror Mn, the negative lens group Gn, the positive lens group Gp, and the second reflecting surface of the plane mirror P. The positive lens group Gp is ​​composed of a positive lens L1, a negative lens L2, a negative lens L3, and a positive lens L4, and the negative lens group Gn is composed of a positive lens L5 and a negative lens L6.

[0043] It is desirable to define the power of each group and each lens under predetermined conditions in order to satisfactorily correct the spherical aberration, field curvature, and astigmatism of the projection optical system 101. When the focal length of the positive lens group Gp is ​​fF, the focal length of the negative lens group Gn is fR, the focal length of the lens L5 in the negative lens group Gn is fl5, and the focal length of the negative lens L6 in the negative lens group Gn is fl6, it is desirable to satisfy conditional expressions (1) and (2).

[0044] 0.06 < |fF / fR| < 0.09 Conditional expression (1) 1.45 < |fl5 / fl6| < 1.75 · Conditional expression (2) If the lower limit of conditional expression (1) is exceeded, the power of the positive lens group Gp becomes relatively large or the power of the negative lens group Gn becomes relatively small, so that the radius of curvature of the concave mirror Mn changes in the direction of increasing, and the Petzval sum changes in the positive direction, which makes it difficult to correct the curvature of field.

[0045] If the upper limit of condition (1) is exceeded, the opposite effect to the above occurs, causing the effective diameter of the negative lens group Gn to increase, which in turn worsens spherical aberration, or causes the radius of curvature of the concave mirror Mn to decrease, causing the Petzval sum to change in the negative direction, making it difficult to correct the curvature of field.

[0046] If the lower limit of conditional expression (2) is not reached, the power of the positive lens L5 becomes relatively large or the power of the negative lens L6 becomes relatively small, so that the radius of curvature of the concave mirror Mn changes in a larger direction, and the Petzval sum changes in a positive direction, which makes it difficult to correct the curvature of field.

[0047] If the upper limit of condition (2) is exceeded, the opposite effect occurs, causing the radius of curvature of the concave mirror Mn to decrease, and the Petzval sum changes in the negative direction, making it difficult to correct the curvature of field.

[0048] In order to suppress the change in the halo component of the axial chromatic aberration and the lateral aberration due to the image height, the dispersion of the glass material is appropriately selected. In addition, it is preferable that the mutually opposing surfaces of the positive lens L1 and the negative lens L2 are concave toward the plane mirror P, and the mutually opposing surfaces of the negative lens L3 and the positive lens L4 are convex toward the plane mirror P. In order to satisfactorily correct the color image surface, it is preferable that the dispersion of the glass material is appropriately selected and that all the surfaces of the positive lens L5 and the negative lens L6 have concave surfaces toward the concave mirror Mn.

[0049] Next, in the first embodiment, the selection of an appropriate glass material will be described.

[0050] Regarding the dispersion of the glass material used, the refractive indices for the i-line (365.5 nm), h-line (405.5 nm), and g-line (435.5 nm) are Ni, Nh, and Ng, respectively. νh=(Nh-1) / (Ni-Ng) It is defined as:

[0051] When the smaller of the vh's of the positive lenses L1 and L4 in the positive lens group Gp is ​​vhgp and the larger of the vh's of the negative lenses L2 and L3 is vhgn, it is preferable that conditional expression (3) be satisfied.

[0052] νhgp-νhgn > 30 Conditional expression (3) This ensures excellent correction of axial chromatic aberration for the i-line (365.5 nm), h-line (405.5 nm), and g-line (435.5 nm).

[0053] In addition, when the νh of the positive lens L5 in the negative lens group Gn is νhl5 and the νh of the negative lens L6 is νhl6, it is preferable that conditional expression (4) be satisfied.

[0054] νhl6 ― νhl5 > 35 Conditional expression (4) This provides excellent correction of field curvature and astigmatism for the i-line (365.5 nm), h-line (405.5 nm), and g-line (435.5 nm).

[0055] Furthermore, in Example 1, the negative lens group Gn can suppress flare light caused by multiple reflections with the concave mirror Mn for the following reasons. In general, if there is a lens surface with a radius of curvature close to that of the concave mirror Mn near the concave mirror Mn, there is a possibility that flare light will be condensed near the substrate 12, which is the image plane, due to multiple reflections with the concave mirror Mn. In Example 1, all of the surfaces of the positive lens L5 and the negative lens L6 have concave surfaces facing the concave mirror Mn and have curvatures with opposite signs, so there is no possibility that flare light will be condensed.

[0056] Table 1 shows the specifications of the first imaging optical system 1011 shown in Fig. 6. From the left, they are the surface number, R (surface curvature radius), D (surface spacing), optical element name, N(i) (refractive index for i-line), N(h) (refractive index for h-line), N(g) (refractive index for g-line), and vh (dispersion).

[0057] [Table 1]

[0058] The values ​​of conditional expressions (1) to (4) are as follows.

[0059] Conditional expression (1) |fF / fR|=0.0695 Conditional expression (2) |fl5 / fl6|=1.66 Conditional expression (3) νhgp-νhgn=37.5 Conditional expression (4) νhl6-νhl5=43.7 The values ​​of the parameters defined in Figures 3 and 4 are as follows:

[0060] R=93.5 x1=68.16 x2=88.89 y0=29 y1=35 d1=15 h1=190 h2=64.81 FIG. 7 shows aberration diagrams of the projection optical system 101 of Example 1. The image heights of the lateral aberration are 0 mm, 29.0 mm, 46.75 mm, 70.125 mm, and 93.5 mm. As shown in these aberration diagrams, the projection optical system 101 has good optical performance. Furthermore, to the right of the lateral aberration, the wavefront aberration RMS of the i-line, which is the dominant wavelength, is shown in the unit λ. It can be seen that the projection optical system 101 of Example 1 has good performance over the entire effective area.

[0061] The design solution of the first embodiment shown in FIG. 5 is for NA=0.15. FIG. 8 shows how far the NA can be increased to enable further fineness for this design solution. In general, the smaller the NA, the easier it is to suppress aberration, and if a design example with a large NA is shown, a design example with an NA smaller than that NA can be easily obtained. On the other hand, a design example with a higher NA means that a design below that NA is possible. An example of NA=0.23 in FIG. 8 is shown, and conditions other than NA are not changed. As shown in FIG. 8, with the increase in NA, the region of x1 and y0 that satisfies the third condition (J3) is limited, and the region of x1 and y0 shown in intermediate colors that satisfies all five conditions becomes smaller. x1=68.16 mm and y0=29 mm in the first embodiment are within the region shown in intermediate colors even for NA=0.23, indicating the possibility of extending the NA to 0.23. The extent to which aberration can be suppressed in an actual design depends on the number of lenses, power arrangement, and the presence or absence of aspheric lenses in the lens design. On the other hand, in the case of NA=0.25 (not shown), x1=68.16 mm and y0=29 mm in Example 1 are located outside the region shown in intermediate colors, and it can be seen that the NA cannot be expanded to 0.25 to satisfy the five conditions. As the NA increases, both x1 and y0 that satisfy the five conditions become smaller. In this way, by solving the simultaneous equations proposed by this embodiment, it is possible to predict the expandability of the high NA. Similarly, it is also possible to predict what the quantities of other parameters such as the lens radius LR, x1, and y0 will be. In FIG. 8, the horizontal axis is x1 and the vertical axis is y0, but other parameters such as NA, LR, d1, and h2 may be used as axes. By solving the simultaneous equations proposed by this embodiment, it is possible to set a combination of design parameters that satisfy any condition value and perform efficient design. EXAMPLES

[0062] FIG. 9 shows the result of solving the simultaneous equations in the same manner as in Example 1, where NA=0.14. In FIG. 9, the area that satisfies the above five conditions is shown in intermediate colors. The design parameters will be described later. The example shown as "design solution" in FIG. 9 will be described below as Example 2.

[0063] FIG. 10 shows the configuration of a projection optical system 101 that constitutes the projection system 10 of the second embodiment.

[0064] The projection optical system 101 constituting the projection system 10 of the second embodiment has NA=0.14, and chromatic aberration is corrected for all of the i-line (365.5 nm), h-line (405.5 nm), and g-line (435.5 nm) that can be used as exposure light. The projection optical system 101 of the second embodiment is a symmetrical optical system with a life-size that is telecentric in the object field and the image field. Therefore, the projection optical system 101 of the second embodiment has the characteristic that coma aberration, distortion aberration, and chromatic aberration of magnification do not occur in principle.

[0065] Table 2 shows the specifications of the first imaging optical system 1011 shown in Fig. 10. From the left, they are the surface number, R (surface curvature radius), D (surface spacing), optical element name, N(i) (refractive index for i-line), N(h) (refractive index for h-line), N(g) (refractive index for g-line), and vh (dispersion).

[0066] [Table 2]

[0067] The values ​​of conditional expressions (1) to (4) are as follows.

[0068] Conditional expression (1) |fF / fR|=0.0662 Conditional expression (2) |fl5 / fl6|=1.56 Conditional expression (3) νhgp-νhgn=37.5 Conditional expression (4) νhl6-νhl5=43.7 The values ​​of the parameters defined in Figures 3 and 4 are as follows:

[0069] R=87.5 x1=64.16 x2=84 y0=24.5 y1=35 d1=32.8 h1=172.12 h2=55.12 FIG. 11 shows aberration diagrams of the projection optical system 101 of Example 2. The image heights of the lateral aberration are 0 mm, 24.5 mm, 43.75 mm, 65.625 mm, and 87.5 mm. As shown in these aberration diagrams, the projection optical system 101 has good optical performance. Furthermore, to the right of the lateral aberration, the wavefront aberration RMS of the i-line, which is the dominant wavelength, is shown in the unit λ. It can be seen that the projection optical system 101 of Example 2 has good performance over the entire effective area. EXAMPLES

[0070] FIG. 12 shows the result of solving the simultaneous equations in the same manner as in Example 1, where NA=0.125. In FIG. 12, the area that satisfies the above five conditions is shown in intermediate colors. The design parameters will be described later. The example shown as "design solution" in FIG. 12 will be described below as Example 3.

[0071] FIG. 13 shows the configuration of a projection optical system 101 that constitutes the projection system 10 of the third embodiment.

[0072] The projection optical system 101 constituting the projection system 10 of the third embodiment has NA=0.125, and chromatic aberration is corrected for all of the i-line (365.5 nm), h-line (405.5 nm), and g-line (435.5 nm) that can be used as exposure light. The projection optical system 101 of the third embodiment is a symmetrical optical system with a life-size that is telecentric in the object field and the image field. Therefore, the projection optical system 101 of the third embodiment has the characteristic that, in principle, coma aberration, distortion aberration, and chromatic aberration of magnification do not occur.

[0073] Table 3 shows the specifications of the first imaging optical system 1011 shown in Fig. 11. From the left, they are the surface number, R (surface curvature radius), D (surface spacing), optical element name, N(i) (refractive index for i-line), N(h) (refractive index for h-line), N(g) (refractive index for g-line), and vh (dispersion).

[0074] [Table 3]

[0075] The values ​​of conditional expressions (1) to (4) are as follows: Conditional expression (1) |fF / fR|=0.0806 Conditional expression (2) |fl5 / fl6|=1.62 Conditional expression (3) νhgp-νhgn=37.5 Conditional expression (4) νhl6-νhl5=43.7 The values ​​of the parameters defined in Figures 3 and 4 are as follows:

[0076] R=84.2 x1=62.88 x2=81.54 y0=21 y1=35 d1=48.18 h1=165.36 h2=53.66 FIG. 14 shows an aberration diagram of the projection optical system 101 of Example 3. The image heights of the lateral aberration are 0 mm, 21.0 mm, 42.10 mm, 63.15 mm, and 84.2 mm. As shown in these aberration diagrams, the projection optical system 101 has good optical performance. Furthermore, to the right of the lateral aberration, the wavefront aberration RMS of the i-line, which is the dominant wavelength, is shown in the unit λ. It can be seen that the projection optical system 101 of Example 3 has good performance over the entire effective area. EXAMPLES

[0077] Table 4 shows the changes in each design variable associated with an increase in the NA of the projection optical system 101. These values ​​are examples, and unless otherwise specified, the present invention is not limited to these values. Also, as mentioned above, the higher the NA, the more difficult it becomes to correct aberrations, and detailed design may be required.

[0078] In Table 4, the NA, y0, y1, x1, d1, and h2 shown in bold are the independent variables, and x2, R, LR, and h1 shown in italics are the dependent variables. Of course, in the simultaneous equations defined by equations (3) and (7), it is arbitrary which variables are taken as independent variables, so it is possible to arbitrarily change the combination of independent and dependent variables. By solving this simultaneous equation, as shown below, the values ​​of the parameters related to the size of the image area, the size of the lens radius, and the layout constraints in relation to the NA can be found, and designable specifications can be determined.

[0079] As the NA increases, y0, y1, and x1 become smaller, and also x2 and R become smaller. This indicates that the image area becomes smaller as the NA increases. In addition, LR becomes larger as the NA increases. This indicates that the lens radius becomes larger as the NA increases. For example, x1, which indicates the image area, is 50 mm at NA=0.30, and 38 mm at NA=0.40. At NA=0.50, the image area is 23 mm, and d1 is 10 mm. Up to NA=0.50, the lens radius LR is less than 150 mm, but at NA=0.60, the lens radius is 282.63 mm, and at NA=0.65, the lens radius is 369.29 mm. According to the example in Table 4, to ensure that x1 is 50 mm or more, NA=0.30 is the upper limit. To ensure that the distance between the apex of the folding mirror and the adjacent lens is 15 mm or more, NA=0.40 is the upper limit. To ensure that the lens radius LR is 150 mm or less, the upper limit is NA = 0.50. To ensure that x1 is 20 mm or more, the upper limit is NA = 0.60. To ensure that x1 is 15 mm or more, the upper limit is NA = 0.65.

[0080] [Table 4]

[0081] In one example, it is preferable that NA, h2, d1, LR, (x2-x1), and x1 satisfy the numerical conditions shown in Table 5.

[0082] [Table 5]

[0083] More preferably, LR is 100 mm or more and 150 mm or less. More preferably, (x2-x1) is 5 mm or more and 25 mm or less. x1 can be, for example, 50 mm. The angle of the hypotenuse of the trapezoid can be, for example, 45 degrees or more and 80 degrees or less.

[0084] In another example, it is preferable that NA, x1, y0, (x2-x1), and LR satisfy the numerical conditions shown in Table 6.

[0085] [Table 6]

[0086] The exposure light, that is, the light that the illumination system irradiates onto the original, may be any of i-line, h-line, and g-line, or may be light having a wavelength of 350 nm or less. EXAMPLES

[0087] FIG. 15 shows Example 5 as a specific example of a method for designing a projection optical system according to an embodiment. In step 1, design parameters are set. The design parameters may include the numerical aperture NA of the projection optical system 101, parameters y0, y1, x1, x2, and R related to the image area, d1 and h1 representing the arrangement constraint, and the lens radius LR. These design parameters are examples. For example, in addition to these design parameters, the distance (gap distance) between the outer diameters of the barrels of the multiple projection optical systems 101 may be set as a parameter of the arrangement constraint, and a change may be made such that the value of this parameter is a desired value (for example, 5 mm or more and 50 mm or less) is added as a condition. In step 2, simultaneous equations are formulated. As a condition to be satisfied by the design parameters set in step 1, simultaneous equations given by Equation (3) and Equation (7) can be set. In step 3, the solution of the simultaneous equations is visualized. For example, as shown in FIG. 5, by setting x1 as the horizontal axis and y0 as the vertical axis, a combination of values ​​of design parameters that satisfy the conditions to be satisfied as a design solution can be visualized. This visualization method is not limited to the above example. In step 4, the values ​​of the design parameters are adjusted. For example, it is shown that, for the values ​​of the design parameters visualized in step 3, other design parameter values ​​are adjusted so that, for example, the lens radius LR becomes a desired value. In step 5, the values ​​of the design parameters are determined. In step 6, initial lens data is determined. This lens data is based on the values ​​of the design parameters determined in step 5. In step 7, detailed design is performed. As the design method, a conventionally known method can be used. Examples of the design solution and the performance of the designed projection optical system are presented as Examples 1, 2, and 3 above.

[0088] Other embodiments An article manufacturing method for manufacturing an article using the above-mentioned exposure apparatus will be described as an example. The article may be, for example, a flat panel display, a liquid crystal display element, a semiconductor IC element, a MEMS, or the like. The article manufacturing method may include an exposure step of exposing a substrate (plate, wafer, glass substrate, or the like) coated with a photosensitive agent using the above-mentioned exposure apparatus, a development step of developing the substrate (photosensitive agent), and a processing step of processing the developed substrate to obtain an article. The processing step may include, for example, etching, resist peeling, dicing, bonding, packaging, or the like. According to this article manufacturing method, it is possible to manufacture an article of higher quality than before.

[0089] Although the embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. For example, the present invention can be applied to a projection optical system of a non-life-size system such as a magnification system or a reduction system, a maskless projection optical system, a multiple exposure system, and an exposure apparatus using a fiber light source or an LED light source. The mask is not limited to a binary mask, and a phase shift mask may be used.

[0090] The invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0091] 10: Projection system, 101: Projection optical system, 11: Original plate, 12: Substrate

Claims

1. 1. An exposure apparatus having a plurality of projection optical systems for projecting an image of an original onto a substrate, each of the plurality of projection optical systems has a trapezoidal exposure area; each of the plurality of projection optical systems includes a first imaging optical system that forms an intermediate image of the original and a second imaging optical system that projects the intermediate image onto the substrate, each of the first imaging optical system and the second imaging optical system includes an optical member, a folding mirror, and a concave mirror; each of the first imaging optical system and the second imaging optical system transmits or reflects an incident light beam through the folding mirror, the optical member, the concave mirror, the optical member, and the folding mirror in this order; and a numerical aperture (NA) of the projection optical system is 0.12 or more and 0.65 or less; a shortest distance d1 between the folding mirror and the optical member that is closest to the folding mirror among the group of optical members arranged between the folding mirror and the concave mirror is 1 mm or more and 20 mm or less; The radius LR of the optical member is 100 mm or more and 400 mm or less, a difference h2 between a distance h1 between a first surface on which the original is disposed and the optical axis of the concave mirror and a radius LR of the optical member is 10 mm or more and 70 mm or less; The difference between x2, which is 1 / 2 the length of the lower base of the trapezoid, and x1, which is 1 / 2 the length of the upper base of the trapezoid, (x2-x1) is 3 mm or more and 25 mm or less, x1 is 10 mm or more and 70 mm or less; An exposure apparatus comprising:

2. When the radius of the circumscribing circle of the trapezoid is R, the distance between the center of the circumscribing circle and the lower base is y0, and the distance between the upper base and the lower base is y1, NA = sin Θ h1=h2+LR tan Θ = y0 / h1, or sin Θ = y0 / h1 (y0+y1)2+(x1)2=R2 LR={R+(h2+d1)×y0 / h1} / (1-y0 / h1) 2. The exposure apparatus according to claim 1, wherein the above expression is satisfied.

3. the folding mirror of each of the first imaging optical system and the second imaging optical system includes a first reflecting surface and a second reflecting surface; each of the first imaging optical system and the second imaging optical system includes a positive lens group disposed between the folding mirror and the concave mirror, and a negative lens group disposed between the positive lens group and the concave mirror; the light from the original is directed to the substrate via the first reflecting surface of the folding mirror, the positive lens group, the negative lens group, the concave mirror, the negative lens group, the positive lens group, and the second reflecting surface of the folding mirror, in that order.

3. An exposure apparatus according to claim 1, wherein the exposure apparatus is a liquid crystal display.

4. the positive lens group is configured to include a first positive lens, a first negative lens, a second negative lens, and a second positive lens, and the negative lens group is configured to include a positive lens and a negative lens, In the wavelength of the exposure light of the exposure apparatus, the focal length of the positive lens group is fF, the focal length of the negative lens group is fR, the focal length of the positive lens in the negative lens group is fl5, and the focal length of the negative lens in the negative lens group is fl6, 0.06 < | fF / fR | < 0.09 1.45 < | fl5 / fl6 | < 1.75 4. The exposure apparatus according to claim 3, wherein the above expression satisfies the above expression.

5. the first positive lens and the first negative lens each have a mutually facing surface that is concave toward the folding mirror, and the second negative lens and the second positive lens each have a mutually facing surface that is convex toward the folding mirror, the positive lens of the negative lens group and the negative lens of the negative lens group each have a mutually opposing surface that is concave toward the concave mirror; 5. The exposure apparatus according to claim 4.

6. The refractive indices of the glass material used in the projection optical system at the i-line (365.5 nm), h-line (405.5 nm), and g-line (435.5 nm) are Ni, Nh, and Ng, respectively, and νh is νh=(Nh-1) / (Ni-Ng) Define it as: When the smaller of the vh of the first positive lens and the second positive lens is vhgp and the larger of the vh of the first negative lens and the second negative lens is vhgn, νhgp−νhgn > 30 Fulfilling When the vh of the positive lens in the negative lens group is vhl5 and the vh of the negative lens in the negative lens group is vhl6, νhl6-νhl5 > 35 6. The exposure apparatus according to claim 4, wherein:

7. the number of the plurality of projection optical systems is six or more; 7. An exposure apparatus according to claim 1, wherein the exposure apparatus is a liquid crystal display.

8. LR is 100 mm or more and 150 mm or less, 8. An exposure apparatus according to claim 1, wherein the exposure apparatus is a liquid crystal display.

9. (x2-x1) is 5 mm or more and 25 mm or less; 9. An exposure apparatus according to claim 1, wherein the exposure apparatus is a liquid crystal display.

10. The angle of the hypotenuse of the trapezoid is 45 degrees or more and 80 degrees or less.

2. The exposure apparatus according to claim 1.

11. x1 is 50 mm; 2. The exposure apparatus according to claim 1.

12. Use any one of i-line, h-line, and g-line as the exposure light.

12. The exposure apparatus according to claim 1,

13. Light having a wavelength of 350 nm or less is used as the exposure light.

12. The exposure apparatus according to claim 1,

14. For at least two values ​​of NA, (y0+y1)2+(x1)2=R2 LR={R+(h2+d1)×y0 / h1} / (1-y0 / h1) 3. The exposure apparatus according to claim 2, wherein the above condition is satisfied.

15. NA is 0.12 or more and 0.15 or less, x1 is 50 mm or more and 70 mm or less, y0 is 70 mm or less, (x2-x1) is 5 mm or more and 25 mm or less, and LR is 100 mm or more and 150 mm or less.

3. The exposure apparatus according to claim 2.

16. an exposure step of exposing a substrate using the exposure apparatus according to any one of claims 1 to 15; a developing step of developing the substrate exposed in the exposure step; a processing step of processing the substrate developed in the developing step to obtain an article; A method for manufacturing an article, comprising:

17. 1. A method for designing a projection optical system in an exposure apparatus having a plurality of projection optical systems that project an image of an original onto a substrate, comprising the steps of: each of the plurality of projection optical systems has a trapezoidal exposure area; each of the plurality of projection optical systems includes a first imaging optical system that forms an intermediate image of the original and a second imaging optical system that projects the intermediate image onto the substrate, each of the first imaging optical system and the second imaging optical system includes an optical member, a folding mirror, and a concave mirror; each of the first imaging optical system and the second imaging optical system transmits or reflects an incident light beam through the bending mirror, the optical member, the concave mirror, the optical member, and the bending mirror in this order; The design method includes: The numerical aperture of the projection optical system is set to a value between 0.12 and 0.65, a shortest distance between the folding mirror and the optical member that is closest to the folding mirror among a group of optical members disposed between the folding mirror and the concave mirror is set to 1 mm or more and 20 mm or less; The radius of the optical member is 100 mm or more and 400 mm or less, a difference between a distance between a first surface on which the original is placed and the optical axis of the concave mirror and a radius of the optical member is set to 10 mm or more and 70 mm or less; The difference between the length of half the lower base and the length of half the upper base of the trapezoid is 3 mm or more and 25 mm or less, The length of the upper base is 10 mm or more and 70 mm or less, determining a configuration of the projection optical system; A design method comprising:

18. Designing a projection optical system according to the design method of claim 17; manufacturing a plurality of projection optical systems according to the design by said process; assembling an exposure apparatus having the plurality of projection optical systems; A manufacturing method of an exposure apparatus comprising:

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