JP7029564B2 - Catadioptric optics, illumination optics, exposure equipment and article manufacturing methods - Google Patents

Description

The present invention relates to catadioptric optical systems, illumination optical systems, exposure apparatus and article manufacturing methods.

The exposure apparatus transfers the pattern of the original plate to a photosensitive substrate (a substrate having a photoresist layer formed on the surface) via a projection optical system in a lithography process for manufacturing articles such as semiconductor devices and display devices. It is a device. For example, an exposure apparatus for manufacturing a display device is required to have the ability to transfer a pattern to a substrate having a larger area with high resolution. In order to meet such demands, a scanning exposure apparatus capable of obtaining a high resolution and exposing a large screen is useful. The scanning exposure apparatus exposes the substrate with light shaped into an arc while scanning the original plate and the substrate. At this time, the original plate is illuminated with the light shaped into an arc shape, and the pattern of the original plate is projected onto the substrate by the light shaped into an arc shape.

Patent Document 1 describes an illumination optical system that illuminates an original plate with light shaped into an arc shape. By the way, in order to illuminate an object with a desired shape and uniform energy, an imaging optical system for forming an image of an opening of a field diaphragm provided in the illumination optical system on the object is required. Generally, such an imaging optical system is called a masking imaging system. When illuminating a large screen, it is desirable that the masking imaging system is composed of a mirror system and has a magnifying power in order to reduce the size of the optical element around the field diaphragm as much as possible.

Patent Document 2 describes an imaging optical system in which aberrations are satisfactorily suppressed. The imaging optical system as described in Patent Document 2 is called an Offner optical system, and the light is bent by three curved mirrors to form an image. The Offner optical system is a one-time imaging system of the same magnification, but as described in Patent Document 3, it is possible to have a magnifying power depending on the positions of the three curvature mirrors. Further, as described in Patent Document 4, there is also an optical system in which aberrations are corrected by imaging a plurality of times.

Special Fair 04-078002 Gazette Japanese Unexamined Patent Publication No. 2010-20017 Japanese Unexamined Patent Publication No. 07-146442 Japanese Unexamined Patent Publication No. 61-203419

However, since the imaging optical system as described in Patent Documents 2 and 3 has a long back focus of the optical system, for example, when mounted on an exposure apparatus, the exposure apparatus can be enlarged. Further, the optical system described in Patent Document 4 has a long overall length due to the multiple image formation, which leads to an increase in the size of the apparatus.

It is an object of the present invention to provide a catadioptric optical system having a small size and an advantageous configuration for reducing aberrations, and an apparatus including the same.

One aspect of the present invention relates to a dioptric optical system, the dioptric optical system being configured to direct light emitted from an object surface toward an image plane, and light extending from the object surface to the image surface. A catadioptric optical system having no image plane between the object surface and the image surface in the optical path of the above, the first reflecting surface, the second reflecting surface, the third reflecting surface, and the fourth reflecting surface. The lens comprises a lens disposed between the object surface and the first reflective surface, the lens has a refractory surface having positive power, and light emitted from the object surface is the refraction. It passes through the surface at least once and reaches the image plane through the first reflecting surface, the second reflecting surface, the third reflecting surface, and the fourth reflecting surface in order, and has the positive power. | P (sum) | | Satisfy.

INDUSTRIAL APPLICABILITY According to the present invention, there is provided a catadioptric optical system having a small size and an advantageous configuration for reducing aberrations, and an apparatus including the same.

The figure which shows the structure of the illumination optical system of one Embodiment of this invention. The figure which shows the schematic structure of the flyeye optical system. The figure which shows the schematic structure of the field diaphragm. The figure which shows the structure of the catadioptric optical system of the design example 1. FIG. The development view of the catadioptric optical system of the design example 1. The figure which shows the sharing degree of the Petzval sum of the catadioptric optical system of the design example 1. FIG. The figure which shows the illumination light shaped into an arc shape. The figure which shows the structure of the catadioptric optical system of the design example 2. FIG. The development view of the catadioptric optical system of the design example 2. The figure which shows the sharing degree of the Petzval sum of the catadioptric optical system of the design example 2. FIG. The figure which shows the structure of the catadioptric optical system of the design example 3. FIG. The development view of the catadioptric optical system of the design example 3. The figure which shows the sharing degree of the Petzval sum of the catadioptric optical system of the design example 3. FIG. The figure which shows the structure of the catadioptric optical system of the design example 4. FIG. The development view of the catadioptric optical system of the design example 4. The figure which shows the sharing degree of the Petzval sum of the catadioptric optical system of the design example 4. FIG. The figure which shows the structure of the catadioptric optical system of the design example 5. The development view of the catadioptric optical system of the design example 5. The figure which shows the sharing degree of the Petzval sum of the catadioptric optical system of the design example 5. The figure which shows the structure of the catadioptric optical system of the design example 6. The development view of the catadioptric optical system of the design example 6. The figure which shows the sharing degree of the Petzval sum of the catadioptric optical system of the design example 6. The figure which shows the structure of the exposure apparatus which concerns on one Embodiment of this invention. The figure explaining the illuminance measurement. The figure explaining the illuminance unevenness correction. The figure which shows the structure of the catadioptric optical system of the design example 7. The development view of the catadioptric optical system of the design example 7. The figure which shows the sharing degree of the Petzval sum of the catadioptric optical system of the design example 7. Diagram showing the effective area of the luminous flux The figure which shows the area to attach the optical film design example 1 or 2. Figure showing area to attach optical film design example 3 and 4 The figure which shows the optical characteristic of the optical film design example 1. The figure which shows the optical characteristic of the optical film design example 2. The figure which shows the optical characteristic of the optical film design example 3. The figure which shows the optical characteristic of the optical film design example 4.

Hereinafter, the present invention will be described with reference to the drawings through exemplary embodiments.

The configuration of the catadioptric optical system according to one embodiment of the present invention will be described with reference to FIGS. 1, 2 and 3. The catadioptric optical system can be incorporated into, for example, the illumination optical system 100 of the exposure apparatus. FIG. 1 shows a configuration example of the illumination optical system 100. The illumination optical system 100 includes a light source unit 120, a wavelength filter 104, a first optical system 105, a deflection mirror 107, a second optical system 140, a flyeye optical system 109, an aperture aperture 110, a third optical system 150, and a field aperture 111. A fourth optical system 160 may be included. The illumination optical system 100 is configured to illuminate the original plate M on the illuminated surface. The light source unit 120 may include a light source 101 and an elliptical mirror 102.

The light source 101 can be, for example, a high pressure mercury lamp, a xenon lamp or an excimer laser. The elliptical mirror 102 is a condensing optical system for condensing the light emitted from the light source 101, and has a shape using a part of the elliptical shape. The light source 101 may be located at one of the two focal points of the elliptical mirror 102 (first focal point).

The light emitted from the light source 101 and reflected by the elliptical mirror 102 is focused on the wavelength filter 104 arranged in the vicinity of the other focal point (second focal point) of the elliptical mirror 102. The wavelength filter 104 changes the spectral distribution of light. The light that has passed through the wavelength filter 104 is guided to the deflection mirror 107 by the first optical system 105 and reflected by the deflection mirror 107. In the example shown in FIG. 1, two light source units 120 are provided, but the number of light source units 120 may be one or three or more.

The first optical system 105 is configured such that the surface 108 is substantially the position of the Fourier transform with respect to the light emitted from the second focal point of the elliptical mirror 102. The light from the Fourier transform surface 108 is guided to the flyeye optical system 109 by the second optical system 140. The second optical system 140 is configured such that the incident surface of the flyeye optical system 109 is substantially a Fourier transform position with respect to the surface 108.

FIG. 2 shows the flyeye optical system 109. As shown in FIG. 2, the flyeye optical system 109 may be composed of two lens groups 131 and 132. Each lens group can be configured by arranging a plurality of plano-convex lenses on a plane. The plano-convex lens constituting the lens group 132 is arranged at the focal position of the plano-convex lens constituting the lens group 131. Further, they are arranged so as to face the convex surface of the plano-convex lens constituting the lens group 131 and the convex surface of the plano-convex lens constituting the lens group 132. A secondary light source distribution (effective light source distribution) is formed on the emission surface side of the flyeye optical system 109.

The luminous flux emitted from the ejection surface of the flyeye optical system 109 is guided to the field diaphragm 111 by the third optical system 150 via the aperture diaphragm 110. The aperture diaphragm 110 determines the incident angle distribution shape (effective light source) of the illuminated surface according to the aperture shape. The third optical system 150 is configured such that the position of the field diaphragm 111 is substantially a Fourier transform plane with respect to the aperture diaphragm 110. Since the secondary light source distribution is formed on the emission surface side of the flyeye optical system 109, the light intensity distribution is uniform on the field diaphragm 111.

FIG. 3 illustrates the shape of the field diaphragm 111. The field diaphragm 111 blocks light other than the arc-shaped transmitting portion 23. The light that has passed through the field diaphragm 111 and is shaped into an arc shape uniformly illuminates the original plate M via the fourth optical system 160. The shape of the opening of the field diaphragm 111 is not limited to the arc shape, and may be another shape. The opening of the field diaphragm 111 may have, for example, a rectangular shape inscribed in an arc shape. The fourth optical system 160 is a catadioptric optical system. Hereinafter, the fourth optical system 160 will be described as a catadioptric optical system 160.

Hereinafter, the catadioptric optical system 160 according to an exemplary embodiment of the present invention will be described with reference to FIGS. 4A, 5A, 6A, 7A, 8A, and 9A. The catadioptric optical system 160 is telecentric with an object surface OBJ and an image plane IMG. The catadioptric optical system 160 includes a first mirror (first reflecting surface) M1, a second mirror (second reflecting surface) M2, a third mirror (third reflecting surface) M3, and a fourth mirror (fourth reflecting surface). May include M4. The catadioptric optical system 160 may also include a refracting surface having positive power disposed between the object surface OBJ and the first mirror M1. The refracting surface may be configured by the lens L1. The light emitted from the object surface OBJ reaches the image plane IMG via the refracting surface, the first mirror M1, the refracting surface, the second mirror M2, the refracting surface, the third mirror M3, and the fourth mirror M4 in this order. ..

The refracting surface may be composed of one lens L1 or at least two lenses. In the latter, the respective surfaces of at least two lenses may form different regions of the refracting surface. The lens L1 may have two refractive planes. The refracting surface may have an aspherical shape. The refraction surface has | P (sum) | << | P (when the third-order Petzval term is P (L1) and the third-order Petzval sum of the entire catadioptric optical system is P (sum). It can be configured to satisfy L1) |.

At least one of the first mirror M1, the second mirror M2, the third mirror M3 and the fourth mirror M4 may have an aspherical shape.

The catadioptric optical system 160 may be configured to have no image plane between the object plane OBJ and the image plane IMG. In other words, the catadioptric optical system 160 may be a one-time imaging optical system having an image plane only on the image plane IMG.

The catadioptric optical system 160 has S1 / TT> 0.1 when the total length of the catadioptric optical system 160 is TT and the distance between the object surface OBJ and the power surface closest to the object surface OBJ is S1. Can be configured to meet. In the catadioptric optical system 160, Sk / S1 <3. When the distance from the object surface OBJ to the power surface closest to the object surface OBJ is S1 and the distance from the final power surface to the image surface IMG is Sk. It can be configured to satisfy zero.

The catadioptric optical system 160 may be configured such that the traveling direction of the light emitted from the object surface OBJ and the traveling direction of the light incident on the image plane IMG are the same. The catadioptric optical system 160 may be configured such that the pupil position of the catadioptric optical system 160 is located between the first mirror M1 and the second mirror M2. The catadioptric optical system 160 may include an aspherical lens for correcting telecentricity in at least one of the vicinity of the object surface OBJ and the vicinity of the image plane IMG.

Hereinafter, a design example of the catadioptric optical system 160 will be described.
(Design example 1)
Table 1A shows the optical specifications of Design Example 1.

The wavelength of light is 365 nm to 435 nm, and Nail is the numerical aperture of the image plane IMG of the catadioptric optical system 160, which is 0.09 in Design Example 1. The exposure width, the slit width, and the arc R are pattern meters that define the shape of the illumination light in the image plane IMG of the fourth optical system 160, and are shown in FIG. 4D. The magnification is the image magnification of the catadioptric optical system 160.

Table 1B shows the configuration of the catadioptric optical system 160 of Design Example 1.

r (mm) is the radius of curvature of the surface, d (mm) is the surface spacing, and n is the glass material. However, the refractive index of air is 1, and the surface of -1 represents a reflective surface. SiO ₂ represents synthetic quartz. The center of curvature of each surface is located on the optical axis.

FIG. 4A shows a cross-sectional view of the catadioptric optical system 160 of Design Example 1. Here, the object surface OBJ of the catadioptric optical system 160 has an arc shape, and FIG. 4A shows light emitted from the center of the arc shape and light emitted from the edges. FIG. 4A shows a cross section passing through the center of the arc shape. Therefore, in FIG. 4A, it seems that the light emitted from the end of the arc shape does not hit the reflecting surface, but the light hits the reflecting surface in the cross section deviated from FIG. 4A. This point is also common to FIGS. 5A, 6A, 7A, 8A, and 9A.

In FIG. 4A, OBJ represents an object plane and IMG represents an image plane. L1 is a lens having a positive power and has two refracting surfaces. The sum of the powers of the two refracting surfaces has a positive power. Therefore, at least one refracting surface has a positive power. M1 is a first mirror (first reflecting surface), M2 is a second mirror (second reflecting surface), M3 is a third mirror (third reflecting surface), and M4 is a fourth mirror (fourth reflecting surface). M1 and M4 are mirrors having positive power (reflecting surface), and M2 and M3 are mirrors having negative power (reflecting surface).

The luminous flux emitted from the object surface OBJ with a predetermined NA is L1 (plane number 1, 2), M1 (plane number 3), L1 (plane number 4, 5), M2 (plane number 6), in order from the OBJ. It passes through L1 (plane numbers 7 and 8), M3 (plane numbers 9), and M4 (plane numbers 10), and is imaged by IMG. The pupil of the catadioptric optical system 160 may be located between M1 and L1 and may have an aperture diaphragm at the pupil position.

FIG. 4B shows a developed view of the catadioptric optical system 160 of Design Example 1. The overall length TT and S1, SK of the catadioptric optical system 160 are defined as shown in FIG. 4B. The developed view is a reference diagram for facilitating the understanding of the overall power arrangement of the catadioptric optical system 160, and the actual catadioptric optical system 160 has a mirror. In FIG. 4B, the mirror is shown with an equivalent thin-walled lens. This point is also common to FIGS. 5B, 6B, 7B, 8B, and 9B.

FIG. 4C shows the third-order Petzval terms of L1, M1, M2, M3, and M4, and the overall third-order Petzval sum (SUM) of the catadioptric optical system 160. Here, the Petzval term is a value obtained by dividing the power of the lens L1 and the mirrors M1, M2, M3, and M4 by the refractive index. The Petzval sum (SUM) is the sum of the cubic Petzval terms of L1, M1, M2, M3, and M4.

Table 1C shows the total lengths TT, S1, and Sk of the catadioptric optical system 160 of Design Example 1.

The total length TT of the catadioptric optical system 160 is a simple sum of the intervals between the plurality of surfaces of the catadioptric optical system 160 from the object surface OBJ to the image plane IMG. That is, the total length TT is a value obtained by integrating the absolute values of d in Table 1B. S1 is the distance from the object surface OBJ to the first power surface (the power surface closest to the object surface OBJ, that is, the surface of surface number 1), and Sk is the final power surface (the power surface closest to the image surface IMG, that is, the surface). It is the distance from the surface of No. 10) to the image surface IMG.

S1 / TT is the ratio of S1 to TT, and if this value is large, for example, a plurality of field diaphragms can be arranged in the vicinity of the object surface OBJ, and the degree of freedom in design is increased. Sk / S1 is the ratio of Sk to S1, and when the catadioptric optical system 160 is a magnifying system, it can be said that the smaller this value is, the more compact the optical system is.

Table 1D shows the optical performance of the catadioptric optical system 160 of Design Example 1.

P (sum) represents the Petzval sum (SUM) of the catadioptric optical system 160, and P (L1) represents the Petzval term of L1. Further, the spot RMS represents the worst value of the RMS spot diameter in the effective region, the dust represents the distortion, and the telecentric (range) represents the variation in the telecentricity in the slit width direction.

As in Design Example 1, the luminous flux emitted from the object surface OBJ passes through the lens L1 over three degrees. As long as the region where the light flux passes through the lens L1 for the first time and the region where the light flux passes through the lens L1 for the second time do not overlap, it is not always necessary to use the same lens L1. However, when it is difficult to separate the region through which the luminous flux is transmitted, such as when the NA of the image plane IMG is large or when the magnification is small, it is necessary to use the same lens L1.
(Design example 2)
Table 2A shows the optical specifications of Design Example 2.

The wavelength of light is 365 nm to 435 nm, and N Air is 0.09. Tables 2B1 and 2B2 show the configuration of the catadioptric optical system 160 of Design Example 2.

The ASP of the surface number 1 represents an aspherical surface, and its shape is represented as a function of h as in the equation (1) using the numerical values shown in Table 2B2. In the formula (1), h is the distance from the optical axis and Z is the position in the optical axis direction.

... Equation (1)
FIG. 5A shows a cross-sectional view of the catadioptric optical system 160 of Design Example 2. OBJ represents an object surface and IMG represents an image plane. L2 is an aspherical lens having a negative power. L1 is a lens having a positive power and has two refracting surfaces. The sum of the powers of the two refracting surfaces has a positive power. Therefore, at least one refracting surface has a positive power. M1 is a first mirror (first reflecting surface), M2 is a second mirror (second reflecting surface), M3 is a third mirror (third reflecting surface), and M4 is a fourth mirror (fourth reflecting surface). M1 and M4 are mirrors having positive power (reflecting surface), and M2 and M3 are mirrors having negative power (reflecting surface).

The luminous flux emitted from the object surface OBJ with a predetermined NA is L2 (plane numbers 1 and 2), L1 (plane numbers 3 and 4), M1 (plane number 5), and L1 (plane numbers 6 and 7) in order from the OBJ. , M2 (surface number 8), L1 (surface number 9, 10), M3 (surface number 11), M4 (surface number 12). The luminous flux is then imaged on the IMG. The pupil of the catadioptric optical system 160 may be located between M1 and L1 and may have an aperture diaphragm at the pupil position.

FIG. 5B shows a developed view of the catadioptric optical system 160 of Design Example 2. FIG. 5C shows the third-order Petzval terms of L1, L2, M1, M2, M3, and M4, and the overall third-order Petzval sum (SUM) of the catadioptric optical system 160.

Table 2C shows the full length TT, S1, Sk, S1 / TT, and Sk / S1 of the catadioptric optical system 160 of the design example 2.

Table 2D shows the optical performance of the catadioptric optical system 160 of Design Example 2.

The catadioptric optical system 160 of the design example 2 has a smaller telecentric value than the catadioptric optical system 160 of the design example 1. This is because the telesen (range) is corrected by the aspherical lens L2 having a negative power.

In Design Example 2, the aspherical lens L2 is arranged in the vicinity of the object surface OBJ, but the aspherical lens L2 can be arranged in the vicinity of the image plane IMG. That is, the aspherical lens can be arranged at least one of the vicinity of the object surface OBJ and the vicinity of the image surface IMG. However, in the case of an enlarged system, the effective diameter of the optical element in the vicinity of the image plane IMG becomes large, so that it is preferably arranged in the vicinity of the object plane OBJ if possible.
(Design example 3)
Table 3A shows the optical specifications of Design Example 3.

The wavelength of light is 335 nm to 405 nm, and NAil is 0.126. Tables 3B1 and 3B2 show the configuration of the catadioptric optical system 160 of Design Example 3.

The ASPs of the surface numbers 2, 4, and 8 represent an aspherical surface, and the shape thereof is defined by the above equation (1). FIG. 6A shows a cross-sectional view of the catadioptric optical system 160 of Design Example 3. OBJ represents an object surface and IMG represents an image plane. L1 is a lens having a positive power and has two refracting surfaces. The sum of the powers of the two refracting surfaces has a positive power. Therefore, at least one refracting surface has a positive power. M1 is a first mirror (first reflecting surface), M2 is a second mirror (second reflecting surface), M3 is a third mirror (third reflecting surface), and M4 is a fourth mirror (fourth reflecting surface). M1 and M4 are mirrors having positive power (reflecting surface), M2 is a mirror having negative power (reflecting surface), and M3 is a planar mirror.

The luminous flux emitted from the object surface OBJ with a predetermined NA is L1 (plane number 1, 2), M1 (plane number 3), L1 (plane number 4, 5), M2 (plane number 6), in order from the OBJ. It passes through L1 (plane numbers 7 and 8), M3 (plane numbers 9), and M4 (plane numbers 10), and is imaged by IMG. The pupil of the catadioptric optical system 160 may be located in the vicinity of M2 and may have an aperture diaphragm at the pupil position.

FIG. 6B shows a developed view of the catadioptric optical system 160 of Design Example 3. FIG. 6C shows the third-order Petzval terms of L1, M1, M2, M3, and M4, and the overall third-order Petzval sum (SUM) of the catadioptric optical system 160.

Table 3C shows the full length TT, S1, Sk, S1 / TT, and Sk / S1 of the catadioptric optical system 160 of the design example 3.

Table 3D shows the optical performance of the catadioptric optical system 160 of Design Example 3.

The catadioptric optical system 160 of the design example 3 has a larger S1 / TT value than the catadioptric optical system 160 of the design examples 1 and 2. Aberrations and telecentricity of the optical system are satisfactorily corrected by the aspherical lens L2, which makes it possible to arrange the power so that S1 becomes large.
(Design example 4)
Table 4A shows the optical specifications of Design Example 4.

The wavelength of light is 365 nm to 435 nm, and NAil is 0.09. Tables 4B1 and 4B2 show the configuration of the catadioptric optical system 160 of Design Example 4.

The ASPs of surface numbers 2, 4, 8 and 9 represent an aspherical surface, and the shape thereof is defined by the above equation (1). FIG. 7A shows a cross-sectional view of the catadioptric optical system 160 of Design Example 4. OBJ represents an object surface and IMG represents an image plane. L1 is a lens having a positive power and has two refracting surfaces. The sum of the powers of the two refracting surfaces has a positive power. Therefore, at least one refracting surface has a positive power. M1 is a first mirror (first reflecting surface), M2 is a second mirror (second reflecting surface), M3 is a third mirror (third reflecting surface), and M4 is a fourth mirror (fourth reflecting surface). M1, M3 and M4 are mirrors having positive power (reflecting surface), and M2 is mirrors having negative power (reflecting surface).

The luminous flux emitted from the object surface OBJ with a predetermined NA is L1 (plane number 1, 2), M1 (plane number 3), L1 (plane number 4, 5), M2 (plane number 6), in order from the OBJ. It passes through L1 (surface numbers 7 and 8), M3 (surface number 9), and M4 (surface number 10). Then, the luminous flux is subsequently imaged by the IMG. The pupil of the catadioptric optical system 160 may be located in the vicinity of L1 and may have an aperture diaphragm at the pupil position.

FIG. 7B shows a developed view of the catadioptric optical system 160 of Design Example 4. FIG. 7C shows the third-order Petzval terms of L1, M1, M2, M3, and M4, and the overall third-order Petzval sum (SUM) of the catadioptric optical system 160. Table 4C shows the full length TT, S1, Sk, S1 / TT, and Sk / S1 of the catadioptric optical system 160 of the design example 4.

Table 4D shows the optical performance of the catadioptric optical system 160 of Design Example 4.

The catadioptric optical system 160 of the design example 4 has a shorter overall length TT than the catadioptric optical system 160 of the design example 1. The aspherical lens L1 and the aspherical mirror M3 satisfactorily correct the aberration and telecentricity of the catadioptric optical system 160, which enables a compact power arrangement as a whole.
(Design example 5)
Table 5A shows the optical specifications of Design Example 5.

The wavelength of light is 335 nm to 405 nm, and Nail is 0.108. Tables 5B1 and 5B2 show the configuration of the catadioptric optical system 160 of Design Example 5.

The ASPs of surface numbers 2, 4, 8 and 9 represent an aspherical surface, and the shape thereof is defined by the above equation (1). FIG. 8A shows a cross-sectional view of the catadioptric optical system 160 of Design Example 5. It shows a cross-sectional view of an optical system. OBJ represents an object surface and IMG represents an image plane. L1 is a lens having a positive power and has two refracting surfaces. The sum of the powers of the two refracting surfaces has a positive power. Therefore, at least one refracting surface has a positive power. M1 is a first mirror (first reflecting surface), M2 is a second mirror (second reflecting surface), M3 is a third mirror (third reflecting surface), and M4 is a fourth mirror (fourth reflecting surface). M1 and M4 are mirrors having positive power (reflecting surface), and M2 and M3 are mirrors having negative power (reflecting surface).

The luminous flux emitted from the object surface OBJ with a predetermined NA is L1 (plane number 1, 2), M1 (plane number 3), L1 (plane number 4, 5), M2 (plane number 6), in order from the OBJ. It passes through L1 (plane numbers 7 and 8), M3 (plane numbers 9), and M4 (plane numbers 10), and is imaged by IMG. The pupil of the catadioptric optical system 160 may be located in the vicinity of L1 and may have an aperture diaphragm at the pupil position.

FIG. 8B shows a developed view of the catadioptric optical system 160 of Design Example 5. FIG. 8C shows the third-order Petzval terms of L1, M1, M2, M3, and M4, and the overall third-order Petzval sum (SUM) of the catadioptric optical system 160. FIG. 8B shows a developed view of the catadioptric optical system 160 of Design Example 5. FIG. 8C shows the third-order Petzval terms of L1, M1, M2, M3, and M4, and the overall third-order Petzval sum (SUM) of the catadioptric optical system 160.

Table 5C shows the full length TT, S1, Sk, S1 / TT, and Sk / S1 of the catadioptric optical system 160 of the design example 5.

Table 5D shows the optical performance of the catadioptric optical system 160 of Design Example 5.

The Catadioptric optical system 160 of Design Example 5 has a smaller Sk / S1 value than the Catadioptric optical system 160 of Design Example 4. This is because the value of NAil is larger than the design value 4, so that M4 is moved to the side of the image plane IMG in order to separate the light reflected by M3 and the light from M4 toward the image plane IMG. ..
(Design example 6)
Table 6A shows the optical specifications of Design Example 6.

The light wavelength is 335 nm to 405 nm, and the NAil is 0.126. Tables 6B1 and 6B2 show the configuration of the catadioptric optical system 160 of Design Example 6.

The ASPs of surface numbers 2, 4, 8 and 9 represent an aspherical surface, and the shape thereof is defined by the above equation (1). FIG. 9A shows a cross-sectional view of the catadioptric optical system 160 of Design Example 6. OBJ represents an object surface and IMG represents an image plane. L1 is a lens having a positive power and has two refracting surfaces. The sum of the powers of the two refracting surfaces has a positive power. Therefore, at least one refracting surface has a positive power. M1 is a first mirror (first reflecting surface), M2 is a second mirror (second reflecting surface), M3 is a third mirror (third reflecting surface), and M4 is a fourth mirror (fourth reflecting surface). M1 and M4 are mirrors having positive power (reflecting surface), and M2 and M3 are mirrors having negative power (reflecting surface).

The luminous flux emitted from the object surface OBJ with a predetermined NA is L1 (plane number 1, 2), M1 (plane number 3), L1 (plane number 4, 5), M2 (plane number 6), in order from the OBJ. It passes through L1 (plane numbers 7 and 8), M3 (plane numbers 9), and M4 (plane numbers 10), and is imaged by IMG. The pupil of the catadioptric optical system 160 may be located in the vicinity of L1 and may have an aperture diaphragm at the pupil position.

FIG. 9B shows a developed view of the catadioptric optical system 160 of Design Example 6. FIG. 9C shows the third-order Petzval terms of L1, M1, M2, M3, and M4, and the overall third-order Petzval sum (SUM) of the catadioptric optical system 160.

Table 6C shows the full length TT, S1, Sk, S1 / TT, and Sk / S1 of the catadioptric optical system 160 of the design example 6.

Table 6D shows the optical performance of the catadioptric optical system 160 of Design Example 6.

The Catadioptric optical system 160 of Design Example 6 has a smaller Sk / S1 value than the Catadioptric optical system 160 of Design Example 4. This is because the value of NAil is larger than the design value 4, so that M4 is positioned closer to the image plane in order to separate the light reflected by M3 and the light toward the image plane IMG from M4.
(Exposure device)
FIG. 10 shows the configuration of the exposure apparatus 400 according to one embodiment of the present invention. The exposure device 400 includes an illumination optical system 100, and scans and exposes the substrate with slit light from the illumination optical system 100. The illumination optical system 100 includes a slit mechanism 181 that can adjust the shape of the opening.

The exposure apparatus 400 includes an original plate stage 300 that holds the original plate, a substrate stage 302 that holds the substrate, and a projection optical system 301 that projects the pattern of the original plate onto the substrate. The projection optical system 301 is, for example, a projection optical system in which a first concave reflection surface 71, a convex reflection surface 72, and a second concave reflection surface 73 are arranged in order in an optical path from an object surface to an image surface.

The exposure apparatus 400 may further include a measuring unit 304 that measures the illuminance unevenness in the exposure region of the substrate by measuring the illuminance distribution of the light that has reached the substrate stage 302. Further, a slit plate 303 is interposed between the substrate stage 302 and the measurement unit 304. The slit plate 303 can be scan-driven in the exposure width direction of FIG. 4D by a driving unit (not shown) under control by a control unit (not shown).

As shown in FIG. 10, the measuring unit 304 may include a sensor 305 and an optical system for guiding the light passing through the slit plate 303 to the sensor 305. The operation of the measuring unit 304 is as follows.

As shown in FIG. 11, the slit plate 303 is scanned in the X direction with respect to the light region 401 imaged on the substrate stage 302. At this time, of the light formed in the region 401, only the light formed in the opening 306 of the slit plate 303 is incident on the measuring unit 304. The light incident on the measuring unit 304 is guided to the sensor 305 via the optical system. The illuminance for each position in the region 401 is measured by reading the energy of the light reaching the sensor 305 while scanning the slit plate 303 in the X direction. This makes it possible to calculate illuminance unevenness.

As described above, the illuminance unevenness can be reduced by adjusting the opening width of the slit mechanism 181 of the illumination optical system 100. For example, it is assumed that the illuminance unevenness as shown in FIG. 12A is measured by the measuring unit 304. In this case, by locally widening the width of the slit mechanism 181 in the portion where the illuminance is decreasing and locally narrowing the width of the slit mechanism 181 in the portion where the illuminance is increasing, FIG. The illuminance distribution can be made uniform.

The article manufacturing method of one embodiment of the present invention may include an exposure step of exposing a substrate by an exposure apparatus 400 and a developing step of developing the substrate. The substrate exposed in the exposure step has a photoresist on its surface, and in the exposure step, a latent image of the pattern of the original plate can be formed on the photoresist. In the developing step, the latent image can be developed to form a resist pattern. After the developing step, for example, the substrate may be etched through the resist pattern or ions may be injected into the substrate. The article that can be formed in this way may include, for example, a display device (display panel), a semiconductor device (semiconductor chip), and the like. (Design example 7)
Table 7A shows the optical specifications of Design Example 7.

The light wavelength is 335 nm to 405 nm, and the NAil is 0.09. Table 7B shows the configuration of the catadioptric optical system 160 of Design Example 7.

FIG. 13A shows a cross-sectional view of the catadioptric optical system 160 of Design Example 7. OBJ represents an object surface and IMG represents an image plane. L1 and L2 are lenses having positive power, respectively, and have two refracting surfaces. The sum of the powers of the two refracting surfaces has a positive power. Therefore, at least one refracting surface has a positive power. M1 is a first mirror (first reflecting surface), M2 is a second mirror (second reflecting surface), M3 is a third mirror (third reflecting surface), and M4 is a fourth mirror (fourth reflecting surface). M1 and M4 are mirrors having positive power (reflecting surface), and M2 and M3 are mirrors having negative power (reflecting surface).

The luminous flux emitted from the object surface OBJ with a predetermined NA is L1 (plane number 1, 2), M1 (plane number 3), L2 (plane number 4, 5), M2 (plane number 6), in order from the OBJ. It passes through L2 (plane numbers 7 and 8), M3 (plane numbers 9), and M4 (plane numbers 10), and is imaged by IMG. The pupil of the catadioptric optical system 160 may be located in the vicinity of L2 and may have an aperture diaphragm at the pupil position.

FIG. 13B shows a developed view of the catadioptric optical system 160 of Design Example 6. FIG. 13C shows the third-order Petzval terms of L1, L2, M1, M2, M3, and M4, and the overall third-order Petzval sum (SUM) of the catadioptric optical system 160.

L1 and L2 of Design Example 7 are examples, and are not limited to these as long as they are lenses having positive power.

Table 7C shows the full length TT, S1, Sk, S1 / TT, and Sk / S1 of the catadioptric optical system 160 of the design example 7.

Table 7D shows the optical performance of the catadioptric optical system 160 of Design Example 7.

L1 and L2 of Design Example 7 are examples, and are not limited to these as long as they are lenses having positive power.
(Antireflection film 1)
The antireflection film of the lens L1 configured in the catadioptric optical system 160 of the design example 4 will be described.

As shown in FIG. 7A, the luminous flux emitted from the object surface OBJ with a predetermined NA is L1 (surface number 1, 2), M1 (surface number 3), L1 (surface number 4, 5), M2 in order from the OBJ. It passes through (surface number 6), L1 (surface number 7, 8), M3 (surface number 9), and M4 (surface number 10). Then, the luminous flux is subsequently imaged by the IMG.

FIG. 14A is a view of the R1 surface (plane close to the OBJ side) of the lens L1 as viewed from the OBJ side. The region 500 surrounded by the chain line in FIG. 14A is an effective region when the light flux emitted from the OBJ first enters the R1 surface of L1, and corresponds to the surface 1 of Table 4B1. The plane incident angle of the light passing through the region 500 is 5 ° to 20 °. Further, the region 501 surrounded by the alternate long and short dash line in FIG. 14A is an effective region when it is incident on the R1 surface of L1 for the second time, and corresponds to the surface 5 of Table 4B1. The plane incident angle of the light passing through the region 501 is 35 ° to 50 °. The region 502 surrounded by the alternate long and short dash line shown in FIG. 14A is an effective region when the lens L1 is incident on the R1 surface for the third time. Corresponds to surface 7 of Table 4B1. The plane incident angle of the light passing through the region 502 is 35 ° to 50 °. The region 503 surrounded by the solid line in FIG. 14B is a region including regions 500, 501 and 502. The optical film of the optical film design example 1 as shown in Table 8A may be provided in the region 503.

Optical film design example 1 is an antireflection film having a three-layer structure using a dielectric material. A thin layer of Al ₂ O ₅ , ZrO ₂ , and Mg F ₂ is layered on the substrate layer SiO ₂ in order. The film thickness of each layer shall be the value shown in the table. However, it is represented by the product nd of the refractive index n of the film type and the physical thickness d of the film.

FIG. 15A shows the reflectance characteristics of the optical film design example 1. It has a reflectance of 2% or less at a wavelength of 350 to 450 nm, an incident angle of 5 ° to 20 °, and a reflectance of 35 ° to 50 °. (Antireflection film 2)
The optical film of the optical film design example 2 as shown in Table 8B may be provided in the region 503.

Optical film design example 2 is an antireflection film having a seven-layer structure using a dielectric material. FIG. 15B shows the reflectance characteristics of the optical film design example 2. It has a reflectance of 1% or less at a wavelength of 350 to 450 nm, an incident angle of 5 ° to 20 °, and a reflectance of 35 ° to 50 °. In the optical film design example 2, the reflectance is suppressed as compared with the optical film design example 1 having a three-layer structure due to the effect of increasing the number of film layers.
(Anti-reflective coatings 3 and 4)
The region 505 surrounded by the solid line shown in FIG. 14C is a region including the region 500. Further, the region 506 surrounded by the solid line in FIG. 14C is a region including the region 501 and the region 502. An optical film design example 3 as shown in Table 8C1 is attached to the region 505, and an optical film design example 4 as shown in Table 8C2 is attached to the region 505.

Optical film design examples 3 and 4 are antireflection films having a three-layer structure using a dielectric material, respectively. FIG. 15C1 shows the optical film design example 3, and FIG. 15C2 shows the reflectance characteristics of the optical film design example 4.

The optical film design example 3 has a characteristic of a reflectance of 1% or less at a wavelength of 350 to 450 nm and an incident angle of 5 ° to 20 °. Further, the optical film design example 4 has a characteristic of a reflectance of 1% or less at a wavelength of 350 to 450 nm and an incident angle of 35 ° to 50 °.

As described above, different types of optical films are attached to the R1 surface of the lens L1 depending on the region. The antireflection films 1 to 4 are examples, and the material, number of layers, film thickness, and the like of the film are not limited thereto.

Although the antireflection film described in the present specification is described by spotting the R1 surface of the lens L1, the antireflection film should be originally applied to the incident surface or the ejection surface of the optical element. Therefore, when there are a plurality of optical elements, it is desirable to optimize the film configuration so that the desired optical characteristics are satisfied on each surface. Further, as for the optical reflective member, it is desirable to form a reflective film (a film having a high reflectance at a desired wavelength) instead of an antireflection film.

160: Catadioptric optical system, OBJ: Object surface, IMG: Image plane, L1, L2: Lens, M1 to M4: Mirror

Claims (12)

A catadioptric structure that is configured to direct light emitted from an object surface toward an image plane and has no image plane between the object surface and the image plane in the optical path of light from the object surface to the image surface. It ’s an optical system,
The first reflecting surface, the second reflecting surface, the third reflecting surface and the fourth reflecting surface,
Includes one lens disposed between the object surface and the first reflective surface.
The lens has a refracting surface with positive power and
The light emitted from the object surface passes through the refracting surface at least once, and passes through the first reflecting surface, the second reflecting surface, the third reflecting surface, and the fourth reflecting surface in order. Reaching the image plane,
When the third-order Petzval term on the refracting surface having positive power is P (L1) and the sum of the third-order Petzval of the entire catadioptric optical system is P (sum),
｜ P (sum) ｜ ＜ ｜ P (L1) ｜
Catadioptric optical system characterized by satisfying. The refracting surface having positive power has an aspherical shape.
The catadioptric optical system according to claim 1 . At least one of the first reflecting surface, the second reflecting surface, the third reflecting surface, and the fourth reflecting surface has an aspherical shape.
The catadioptric optical system according to claim 1 or 2 . When the total length of the catadioptric optical system is TT and the distance between the object surface and the power surface closest to the object surface is S1.
S1 / TT> 0.1
The catadioptric optical system according to any one of claims 1 to 3 , wherein the catadioptric optical system satisfies. When the distance from the object surface to the power surface closest to the object surface is S1, and the distance from the final power surface to the image surface is Sk.
Sk / S1 <3.0
The catadioptric optical system according to any one of claims 1 to 4 , wherein the catadioptric optical system satisfies. The traveling direction of the light emitted from the object surface is the same as the traveling direction of the light incident on the image plane.
The catadioptric optical system according to any one of claims 1 to 5 . The pupil position of the catadioptric optical system is located between the first reflecting surface and the second reflecting surface.
The catadioptric optical system according to any one of claims 1 to 6 . At least one of the vicinity of the object surface and the vicinity of the image plane further includes an aspherical lens for correcting telecentricity.
The catadioptric optical system according to any one of claims 1 to 7 . It is formed on an optical film formed on a refracting surface arranged between the object surface and the first reflecting surface, and on a refracting surface arranged between the second reflecting surface and the third reflecting surface. The catadioptric optical system according to any one of claims 1 to 8 , wherein the optical film is of a different type from each other. An illumination optical system comprising the catadioptric optical system according to any one of claims 1 to 9 . An exposure apparatus having the catadioptric optical system according to any one of claims 1 to 9 . The step of exposing the substrate by the exposure apparatus according to claim 11 .
The process of developing the substrate and
A method for manufacturing an article, which comprises the above and manufactures an article from the substrate.

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