JPH0562721B2 - - Google Patents

Description

[Detailed description of the invention]

(Technical Field of the Invention) The present invention relates to a reflective optical system for projecting and exposing a pattern of a mask (original plate) onto a wafer coated with photoresist when manufacturing integrated circuits such as ICs and LSIs. (Background of the Invention) Conventionally, this type of reflective optical system projects a mask surface onto a wafer surface at the same magnification. For example, as is known as Offner's optical system, a reflective optical system that uses concave and convex reflective surfaces to form a good image in an arc-shaped field of view was developed in the 1980s.
-Disclosed in Publication No. 51083, etc. Further, a reflective optical system using one concave reflective surface and a refractive member,
By J.Dyson, Unit
Magnification Optical System without Seidel
Journal of Optical with the title “Aberrations”
Published in Society of America.vol.49, p713, (1959). Efforts have been made to improve the performance of Offner's optical system by inserting a meniscus-shaped lens member.
It can also be found in Publication No. 85722. Also,
Dyson's optical system has various improvements, including the introduction of achromatic achromat.
A Unit-Power Telescope by G.Wynne
Optical with the title “for Projection Copying”
Instruments and Techniques (published by
Oriel Press Limited, edited by JHDickson)
(1970). However, since all of these have a unit magnification, when used as an optical system for a projection exposure device, the mask (original plate) must be made to the same size as the actual integrated circuit, which makes it difficult to manufacture the mask. It was accompanied by difficulties. There are also optical systems that perform reduced projection using only a refractive system without using a reflective surface, but these are generally composed of more than a dozen glass members, so
This has the problem that the absorption of light by the glass member increases. In particular, when shortening the exposure wavelength and using wavelengths in the deep ultraviolet region in order to accommodate integrated circuit patterns that will become increasingly finer in the future, absorption in glass materials becomes a major problem, and refractive systems alone will not be able to miniaturize the patterns. It is expected that there will be limits. (Objective of the Invention) An object of the present invention is to solve the above-mentioned problems and to provide a reflective optical system that is capable of exposure with light in the far ultraviolet region and that also allows reduction projection without any difficulties in mask manufacturing. It is about providing. (Summary of the Invention) The principle configuration of the catoptric _reduction projection optical system according to the present invention is as in the configuration of the first embodiment shown in FIG. ₂ . The first partial optical system S ₁ and the second partial optical system S ₂ are reduction type reflective optical systems that each have a concentric reflective surface, a concentric refractive surface, and a plane refractive surface that includes a concentric center and is perpendicular to the optical axis. The first partial optical system forms a reduced image of the object, and the second partial optical system forms an object image further reduced from this reduced image. The first partial optical system S ₁ includes a concave reflecting surface M ₁ as a first reflecting surface arranged substantially concentrically,
It has a convex reflective surface M ₂ as a second reflective surface and a concave reflective surface M ₃ as a third reflective surface, and the first reflective surface
M ₁ and the third reflective surface M ₃ are arranged opposite to the second reflective surface M ₂ . The object plane O and the image plane I of the first partial optical system S ₁ are in a plane that includes the concentric center C of the first partial optical system and is perpendicular to the optical axis A ₁ of the optical system. Then, on the exit side of the third reflective surface _M3 , there is a refractive surface _R1 as an incident surface substantially concentric with the concentric center C.
and a refractive surface R ₂ as an exit surface that is disposed near the image plane I and substantially parallel to _the image plane. Moreover, the second partial optical system S ₂ is
It has a concave reflective surface _M4 as a fourth reflective surface centered on the concentric center C of the first partial optical system _S1 or a point optically equivalent thereto, and has an image plane I of the first partial optical system. As the object plane O', the object plane O' and the image plane I' of the second partial optical system are defined in a plane that includes the center of curvature of the fourth reflective surface and is perpendicular to the optical axis _A2 of the second partial optical system. and a refractive surface as an incident surface substantially concentric with the center of curvature C of the fourth reflective surface on the exit side of the fourth reflective surface.
R ₃ and a refractive member having a refractive surface R ₄ as an exit surface arranged near the image surface I' and substantially parallel to the image surface.
It has P ₂ . In the concentric optical system of the present invention, if the object plane and the image plane are set within a plane including the concentric center, the optical axis is defined as a straight line passing through the concentric center and perpendicular to this plane. Therefore, in the case of FIG. 1, the optical axis A ₁ and the optical axis A ₂ coincide on the same straight line. In the configuration of the first embodiment shown in FIG. 1, the first reflective surface _M1 and the third reflective surface _M3 are on the same curved surface, resulting in a simple configuration, but this is not limiting. It's not something you can do. Further, although the second reflecting surface M ₂ and the incident surface R ₁ of the refractive member P ₁ have the same radius of curvature, it is not necessary that they also match. The image plane of each partial optical system is configured to match the exit surface of each refractive member, but it is also possible to separate them slightly, especially at the final image plane of the optical system. In order to perform so-called photoetching, it is effective to provide an air gap of several millimeters. Further, when a slight air gap is provided between the refractive member and the image plane at the final image plane, the exit surface of the refractive member to be disposed near the intermediate image at the intermediate image plane is It is located slightly closer to the injection side than the
It tends to be desirable to form an intermediate image in the refractive member. In reflective optical systems, the advantage of arranging optical surfaces concentrically and arranging object points and image points in a plane that includes the center and is perpendicular to the optical axis has been pointed out for a long time. For example, Gramatein (AP
Grammatin), “Some Properties of
Under the title “Concentric Optical Systems”
It is described in Optical Technology vol.38No.4p, 210 (1970), but here we will give a brief overview of its properties. Since all the optical surfaces are concentric, the inclination angle of the paraxial ray emitted from the point on the optical axis on the object surface, that is, the concentric center point, does not change its value except for the sign. Therefore,
The imaging magnification is equal to the ratio of the refractive indices of object space and image space. Similarly, a ray of light that leaves an object point on the optical axis does not change its angle of inclination, regardless of its numerical aperture (NA). Therefore, the spherical aberration and sine conditions are strictly zero. In particular, satisfying the sine condition is equivalent to eliminating coma aberration at least in the third-order aberration region. Furthermore, considering the image plane due to the spherical beam and the image plane due to the meridional ray, the image surface due to the spherical beam has no field curvature for the same reason that the spherical aberration is zero. Therefore, if the radii of curvature of the reflecting surface and the refractive surface are appropriately selected so that the Petzval sum becomes zero, it is possible to eliminate astigmatism. In addition, in the configuration of the present invention, there is a plane as the exit surface of the refractive member near the plane perpendicular to the optical axis including the object plane and the image plane, but the same applies to the discussion regarding aberrations as described above. holds true. As described above, in an optical system in which all optical surfaces are concentric, it is possible to eliminate at least four aberrations related to image sharpness, excluding distortion, out of the so-called Seidel's five aberrations. (Example) Hereinafter, the present invention will be described in detail based on the configuration of the illustrated example. The configuration of the first embodiment shown in FIG. 1 is the most basic configuration of the reflective reduction projection optical system according to the present invention, and the light from the object point O of the first partial optical system _S1 is Concave reflective surface as a reflective surface
Convergent action of M ₁ , convex reflective surface as second reflective surface
An image I of the first partial optical system is formed under the diverging action of M ₂ and the convergence action of the concave reflecting surface M ₃ as the third reflecting surface, and the refractive action of the first refractive member P ₁ . In this case, the imaging magnification β ₁ is, as stated in equation (1) in the paper by Grammatein,
When the refractive index of the first refractive member P ₁ is n ₁ , it is expressed as β ₁ =−1/n ₁ . Next, the image I of the first partial optical system _S1 becomes the object O' of the second partial optical system _S2 , and the light from there is focused on the concave reflective surface _M4 as the fourth reflective surface. Under the action and the refraction action of the second refraction member P ₂ ,
Object image I' is formed. Second partial optical system in this case
Similarly, the imaging magnification β ₂ of S ₂ is expressed as β ₂ =−1/n ₂ where n ₂ is the refractive index of the second refractive member P ₂ . Therefore, the imaging magnification β _T of the entire system is
It is the product of the imaging magnifications of the first and second partial optical systems, and is β _T =-1/(n ₁ ·n ₂ ). Therefore, for the sake of simplicity, let us assume that the refractive index of the first refractive member P ₁ and the second refractive member P ₂ is equal to n.
The image of the object will be reduced by n squared by the entire system. Now, the fourth reflective surface M ₄ of the second partial optical system S ₂
Assuming that the position of is the aperture stop of the entire system, in order to be telecentric on the image side, the fourth reflecting surface
It is sufficient that the light ray emitted on the optical axis of M ₄ is incident on the image plane I' perpendicularly, that is, parallel to the optical axis, and the condition of n/R _M4 - (n-1)/R _P2 = 0 (1) is satisfied. It is necessary to meet the requirements. Here, R _M4
represents the radius of curvature of the fourth reflective surface _M4 , and R _P2 represents the radius of curvature of the incident surface _R3 of the second refractive member _P2 . In addition, in the figure, the direction in which the ray travels from left to right is positive, the radius of curvature of the curved surface with the convex surface facing the left side is positive, and the radius of curvature of the curved surface with the concave surface facing the left side is negative. In a medium in which the light ray travels in the direction, the refractive index is positive, and in a medium in which the light ray travels in the negative direction, the refractive index is negative. (The same definition applies in the following explanation.) On the other hand, the Petzval sum PZ ₂ of the second partial optical system S ₂
is PZ ₂ =2/R _M4 −(n-1)/(n・R _P2 ) (2). Substituting equation (1) into equation (2) yields PZ ₂ =1/R _M4 <0 (3). It is therefore clear that the second optical subsystem S ₂ essentially has a negative Petzval sum insofar as it is telecentric on the image side. By the way, the Petzval sum of the first partial optical system S ₁
PZ ₁ is expressed as PZ ₁ =-2/R _M1 +2/R _M2 -2/R _M3 +(n-1)/(n·R _P1 ) (4). Here, for simplicity, the radii of curvature of the first reflecting surface and the third reflecting surface are equal (R _M1 = R _M3 ), and the radius of curvature of the second reflecting surface and the radius of curvature of the incident surface of the first refracting member are the same. (R _M2 = R _P1 ), then PZ ₁ = -4/R _M1 +2/R _M2 + (n-1)/(n・R _M2 ) (5), and now the refractive index of the first refractive member Assuming that n=1.5, as long as 12/7≒1.7<R _M1 /R _M2 , the Petzval sum of the first partial optical system _S1 is
PZ ₁ is such that PZ ₁ >0. That is, the radius of curvature R _M1 of the first reflecting surface and the second
As long as the radius of curvature R _M2 of the reflecting surfaces is made to differ by a factor of 1.7 or more so that reciprocating reflection between them is practically possible, the first partial optical system essentially has a positive Petzval sum. In this way, since the Petzval sums of the first partial optical system and the second partial optical system have different signs, the Petzval sum of the entire system is corrected by combining these partial optical systems. Is possible. Specifically, the sum PZ T of the Petzval sum PZ ₂ of the second partial optical system given by formula (2) and the Petzval sum PZ ₁ of the first partial optical system given by formula (4) becomes _zero . By selecting the radius of curvature of each surface so that PZ _T =PZ ₁ +PZ ₂ =0, it is possible to completely correct the Petzval sum of the entire system. From the above discussion, the first partial optical system and the second partial optical system not only share the reduction magnification with each other in principle, but also by combining both partial optical systems, the Petzval of each partial optical system It is clear that the Petzval sum of the entire system can be well corrected by canceling the sums. This can also be read from the basic configuration diagram shown in FIG. That is,
According to the ray representing the conjugate relationship between the object point and the image point shown in _FIG . On the other hand, the focal point of the second partial optical system S ₂ on the image plane I′ coincides with the plane perpendicular to the optical axis, and the first partial optical system and the second partial optical system It can be seen that the curvature of the image plane is well corrected by combining the images. Specific numerical examples of the first embodiment are shown in Table 1 below. The following tables, including Table 1, show the radius of curvature, surface spacing, and refractive index of each curved surface in the order from the object surface O side toward the final image surface I'. In the table, the radius of curvature and the refractive index of each surface are defined as positive in the traveling direction of the light ray going from left to right in the figure, and their positive and negative values are determined based on this, and the surface spacing is in the traveling direction of the light ray. It is assumed to be positive in a medium where is positive, and negative in a medium in which the traveling direction of the ray is negative. Therefore,
In the illustrated configuration of the first embodiment, for example, since the light ray from the object plane O first moves from right to left, the distance between the object plane O and the first reflecting surface _M1 and the refractive index therebetween are negative. Given as a value.

[Table] According to the numerical example of the first embodiment, it is clear that the Petzval sum is completely corrected by the combination of the first partial optical system and the second partial optical system. FIG. 2 is a diagram showing the basic configuration of a second embodiment of the present invention, and members having the same functions as the basic configuration shown in FIG. 1 are given the same symbols. In this second embodiment, in order to correct chromatic aberration, the first refractive member P ₁ and the second refractive member P ₂ are each constituted by a group of refractive members that are divided or joined together. In the configuration of the optical system according to the present invention, since the reflective portion has a large power, it is easy to remove chromatic aberration when designing with chromatic aberration in mind. Since the refractive and reflective surfaces of the optical system are all approximately concentric, and the plane refractive surface that includes the concentric center and is perpendicular to the optical axis approximately coincides with the image plane, axial chromatic aberration is reduced by each refraction. It almost never occurs, regardless of the dispersion of the parts. Therefore, what is mainly required to correct chromatic aberration is chromatic aberration of magnification. The configuration of the second embodiment shown in FIG. 2 is intended to satisfactorily correct chromatic aberration of magnification.
For this purpose, the first refractive member P ₁ is composed of a concentric meniscus lens member P ₁₁ and a positive lens member P ₁₂ arranged with a slight space between them, and the second refractive member P ₂ is composed of a concentric meniscus lens member P 11 . shaped meniscus lens member
P ₂₁ and a positive lens member P ₂₂ joined thereto. Not limited to the illustrated configuration, it is possible to configure predetermined first and second refractive members by separating or joining two or more types of refractive members, and in order to correct chromatic aberration, the separating surface of the refractive member The joint surfaces do not necessarily have to be concentric. Note that if good imaging performance is ensured for the reference light beam, it is possible to correct chromatic aberration independently, so in the following examples, monochromatic light is assumed for simplicity, and chromatic aberration is corrected. shall not be particularly considered. The configuration of the third embodiment shown in FIG. 3 is such that between the object plane O and the first reflecting surface _M1 in the first partial optical system,
A concentric meniscus lens member _L1 is inserted, and a convex reflective surface is also provided as a second reflective surface.
_M2 is configured as a back reflective surface of the same member as the meniscus lens member _L1 . In the basic configuration according to the present invention described above in FIG. 1, curvature of the child image surface occurs due to higher-order aberrations, but it is possible to adopt a concentric meniscus-shaped lens member as shown in this third embodiment. This makes it possible to significantly reduce the curvature of the meridional plane. The configuration _of the fourth embodiment shown in _FIG . A concentric meniscus lens member _L2 is also arranged between the two. This meniscus lens member _L2 has the same radius of curvature as the concentric refractive surface serving as the entrance surface of the second refractive member _P2 . By adding this meniscus lens member _L2 , as can be seen from the figure, both the object point and the image point can be set closer to the optical axis without causing vignetting of the light beam. Generally, in an optical axis optical system, the closer to the optical axis, the better the image formation due to aberrations. This has a great effect in further improving performance. Table 2 below shows specific numerical examples of the fourth embodiment. This table also uses the same notation system as Table 1 above, but in each partial optical system, the joining surface (the surface indicated by the dotted line in the figure) of the refractive member and the meniscus lens member provided in conjunction with this refractive member is: This surface was excluded because the refractive index before and after it was assumed to be the same.

[Table] Also in the numerical example of the fourth embodiment, it is clear that the Petzval sum is completely corrected by the combination of the first partial optical system and the second partial optical system. The configuration of the fifth embodiment shown in FIG. 5 is such that each concave reflective surface of the first partial optical system and the second partial optical system is configured as a back reflective surface. With such a configuration, it is possible to better correct high-order spherical aberration regarding off-axis light beams. The configuration of the sixth embodiment shown in FIG. 6 is the same as that of the fourth embodiment shown in FIG. This system includes a partial optical system _S3 of equal magnification. In the equal-magnification third partial optical system _S3 , all the reflecting surfaces and refracting surfaces are arranged almost concentrically, and the concentric center point C' is connected to the concentric center of the reflecting reduction system by the plane reflecting mirror M _P1 . It is set at a position optically equivalent to point C. Specifically, the equal-magnification partial optical system _S3 is the fifth
It has a concave reflective surface _M5 as a reflective surface, a convex reflective surface _M6 as a sixth reflective surface, and a concave reflective surface _M7 as a seventh reflective surface. Meniscus lens member L ₃ ,
It has L ₄ . In this configuration, the second sub-optical system S ₂ essentially has a negative Petzval sum.
On the other hand, the third partial optical system _S3 has a positive Petzval sum, and the Petzval sum as a whole system is corrected by the positive Petzval sum of the first partial optical system _S1 . Although some distortion aberration occurs in the configuration of the fourth embodiment shown in FIG. 4, in the configuration of this sixth embodiment,
By configuring the optical surface of S ₃ asymmetrically between the forward and return paths, it is possible to reduce distortion. Table 3 below shows specific numerical examples of the sixth embodiment. This table also uses the same notation system as Table 2 above, but the plane reflecting mirror is not essential in terms of optical design, so it is excluded.

【table】

[Table] In the numerical example of the sixth embodiment, in addition to the combination of the first partial optical system and the second partial optical system,
It is clear that the Petzval sum is completely corrected even by combining the partial optical systems. In the seventh embodiment of the present invention shown in FIG. 7, a reduction type reflective optical system is provided as a third partial optical system _S3 in addition to the first and second partial optical systems _S1 and _S2 . It is something. Also in FIG. 7, members having the same functions as those in other embodiments are given the same symbols.
This third partial optical system _S3 is basically the same optical system as the first partial optical system _S1 , and the refractive index of the third refractive member _P3 disposed on the image side of the third partial optical system is Assuming that n is the same as for the other refractive members P ₁ and P ₂ , the imaging magnification β _T of the entire optical system is β _T =−1/n ³ . The first partial optical system _S1 basically has the same configuration as the fifth embodiment shown in FIG. 5, but is installed obliquely so that the object plane O is parallel to the optical axis _A1 . A plane reflecting mirror M _P1 is arranged. In addition, in order to make the image plane I parallel to the optical axis _A1 , a reflective surface M _P2 is provided in the first refractive member _P1 , and the exit surface _R2 of the first refractive member _P1 is aligned with the optical axis _A1. configured to be parallel. Then, the first refractive member _P1 and the meniscus lens member
It is integrally formed with L ₁ from the same material.
The second partial optical system _S2 is also basically the same in configuration as the fifth embodiment shown in _FIG . The second refractive member _P2 has a reflective surface M _P4 like the first refractive member _P1 , and the image plane I' is parallel to the optical axis _A2 . The third partial optical system S ₃ includes a concave reflective surface M ₅ as a fifth reflective surface and a convex reflective surface M ₆ as a sixth reflective surface.
and has a concave reflective surface M ₇ as a seventh reflective surface,
Furthermore, the seventh reflecting surface M ₇ and the image plane of the third partial optical system
A _third refractor having a concentric center point C′, a refractive surface R ₅ as a concentric incident surface, and a plane R ₆ as an exit surface parallel to and close to the image surface I ₀ as an exit surface. It has member _P3 . In this embodiment, the fifth reflective surface _M5 and the seventh reflective surface _M7 have the same radius of curvature and are formed as the same concave reflective surface.
Furthermore, a concentric meniscus lens member L ₃ is arranged between the object plane O ₀ and the fifth reflecting surface M ₅ , and this concentric meniscus lens member L ₃ is made of the same material as the third refractive member P ₃ . It is integrally constructed. The concentric center point C ₁ of the first partial optical system S ₁ and the concentric center point _{C 2} of the second partial optical system S 2 are equivalent with respect to the flat reflective surface M _P2 provided on the first refractive member. The concentric center point C ₃ of the fourth reflecting surface M ₄ consisting of the back reflecting mirror in the two-part optical system is equivalent to the point C ₂ with respect to the plane mirror M _P3 . In addition, the third partial optical system
The concentric center point C' of _S3 is the first partial optical system with respect to the plane mirror M _P1 and the plane reflection surface M _P5 in the third refractive member.
It is equivalent to the concentric center point C ₁ of S ₁ . According to the configuration of the seventh embodiment, the object plane
O ₀ and the final image plane I' are provided parallel to each other at different positions, making it possible to provide a space for arranging an illumination optical system for supplying illumination light to the object plane. (Effects of the Invention) As described above, according to the present invention, a reduction projection type reflective optical system that is advantageous for manufacturing integrated circuits is achieved. Moreover, in order to perform reduction projection, concentric reflecting surfaces,
In an optical system that includes a concentric center and a flat refractive surface perpendicular to the optical axis, the Petzval sum that cannot be simply corrected as long as telecentricity is maintained on the image side is corrected by including a concentric reflective surface and a concentric center. By combining two reduction-type reflective optical systems each having a flat reflective surface perpendicular to the optical axis, it is possible to perform good correction and eliminate field curvature. In addition, by using a reflective optical system that can perform projection at such a reduction magnification, it is possible to create a mask (original plate) for an integrated circuit pattern that is larger than the actual size of the circuit, making mask manufacturing extremely easy. In addition, it is also very effective in manufacturing integrated circuits with finer patterns. Furthermore, even when using light in the far ultraviolet region as the exposure wavelength, there is a small number of refractive members such as glass, so there is an advantage that the transmittance is not deteriorated due to absorption by these members. Furthermore, most of the refractive power of the entire optical system depends on convex and concave reflective surfaces, so when designing with chromatic aberration in mind, it is difficult to remove chromatic aberration in the case of an optical system consisting only of a refractive system. It also has the advantage of being relatively easy.

[Brief explanation of the drawing]

FIG. 1 is an optical configuration diagram of a first embodiment consisting of the basic configuration of a catoptric projection optical system according to the present invention, FIG. 2 is a configuration diagram of a second embodiment according to the present invention, and FIG. 3 is a diagram of a configuration according to the present invention. Fig. 4 is a block diagram of the fourth embodiment according to the present invention, Fig. 5 is a block diagram of the fifth embodiment according to the present invention, and Fig. 6 is a block diagram of the sixth embodiment according to the present invention. Block diagram, FIG. 7 is a block diagram of a seventh embodiment according to the present invention. Explanation of symbols of main parts, S ₁ .... first partial optical system, P ₁ .... first refractive member, S ₂ .... second partial optical system, P ₂ .... second refractive member, S ₃ .... 3-part optical system, O, O'...object surface, _M1 ...concave first reflecting surface, I, I'...imaging surface, _M2 ...convex second reflecting surface,
M ₃ ... concave third reflective surface, M ₄ ... concave fourth reflective surface.

Claims (1)

[Scope of Claims] 1. A first partial optical system that forms a reduced image of an object on an object plane, and a second partial optical system that forms an image that is further reduced from the image formed by the first partial optical system. The first partial optical system has a concave reflective surface, a refractive member disposed on the exit side of the concave reflective surface, and a predetermined optical axis, and the first partial optical system has an object plane and an image plane. is substantially located in a plane that includes the center of curvature of the concave reflective surface and is perpendicular to the optical axis of the optical system or in a plane that is optically equivalent to this plane, and the refractive member of the first partial optical system has the center of curvature. The second partial optical system has a refractive surface substantially concentric with the center and a refractive surface located near the image plane of the first partial optical system and substantially parallel to the image plane, and the second partial optical system A second concave reflective surface whose center is approximately at the center of curvature of the concave reflective surface or a point optically equivalent thereto, a refractive member disposed on the exit side of the second concave reflective surface, and a predetermined optical axis. and the object plane and image plane of the second partial optical system include the center of curvature and
The object plane of the second partial optical system is located approximately in a plane perpendicular to the optical axis of the partial optical system or in a plane optically equivalent to this plane, and the object plane of the second partial optical system is the image plane of the first partial optical system or its conjugate. the refractive member of the second partial optical system has a refractive surface substantially concentric with the center of curvature, and a refractive surface located near the image plane of the second partial optical system and substantially parallel to the image plane. A catoptric reduction projection optical system characterized by: 2. A first partial optical system that forms a reduced image of an object on an object plane, and a second partial optical system that forms an image that is further reduced from the image formed by the first partial optical system; The optical system includes a concave reflective surface as a first reflective surface, a convex reflective surface as a second reflective surface, a concave reflective surface as a third reflective surface, and an exit side of the third reflective surface, which are arranged substantially concentrically. and a predetermined optical axis, and the object plane and image plane of the first partial optical system are within a plane including the concentric center and perpendicular to the optical axis of the optical system, or this plane. The refractive member of the first partial optical system is located approximately in a plane optically equivalent to
The second partial optical system has a refractive surface located near the image plane of the partial optical system and substantially parallel to the image plane, and the second partial optical system has a concentric center of the first partial optical system or a point optically equivalent thereto. The second partial optical system has a concave reflecting surface as a fourth reflecting surface, a refractive member disposed on the exit side of the fourth reflecting surface, and a predetermined optical axis. The image plane includes the concentric center and the second
The object plane of the second partial optical system is located approximately in a plane perpendicular to the optical axis of the partial optical system or in a plane optically equivalent to this plane, and the object plane of the second partial optical system is the image plane of the first partial optical system or its conjugate. The refractive member of the second partial optical system has a refractive surface substantially concentric with the concentric center and a refractive surface located near the image plane of the second partial optical system and substantially parallel to the image plane. A catoptric reduction projection optical system characterized by: 3. In the catoptric projection optical system according to claim 2, the first reflective surface of the first partial optical system and the third reflective surface have the same radius of curvature and are integral reflective surfaces. A catoptric reduction projection optical system characterized by being configured as follows. 4. In the catoptric projection optical system according to claim 3, the second partial optical system is telecentric on the image side, and the radius of curvature of the first and third reflective surfaces of the first partial optical system is , a reflection reduction projection optical system characterized in that the radius of curvature of the second reflection surface is greater than 1.7 times.