KR20130112753A - Optical system, exposure apparatus and device manufacturing method - Google Patents

Abstract

PURPOSE: An optical system, an exposure apparatus, and a device manufacturing method are provided to independently adjust the focus or the magnification of the projective optical system. CONSTITUTION: An optical system (40) comprises a first optical element (41), a second optical element (42), and a third optical element (43). The first optical element has a plane (41a) and a curved surface (41b). The plane meets at right angles to the optical axis of the projective optical system. The curved surface is formed on the opposite side of the plane. The second optical element has a curved surface (42a). The curved surface of the second optical element is opposite to the curved surface of the first optical element. The third optical element has a cylindrical surface (43b). The cylindrical surface has a bus in a first direction perpendicular to the optical axis of the projective optical system.

Description

Optical system, exposure apparatus and device manufacturing method {OPTICAL SYSTEM, EXPOSURE APPARATUS AND DEVICE MANUFACTURING METHOD}

The present invention relates to an optical system, an exposure apparatus having an optical system, and a device manufacturing method for manufacturing a device using the exposure apparatus.

It is a figure which shows the structure of the projection optical unit which comprises the projection optical system of the conventional exposure apparatus. This exposure apparatus is called a multi-scan type projection exposure apparatus, and is equipped with a mechanism for adjusting the focus position and magnification among a plurality of projection optical units (Japanese Patent Laid-Open No. 2004-145269). The exposure apparatus includes a mask stage MS for scanning the mask M disposed on the object plane OP of the projection optical system, and a substrate stage PS for scanning the glass substrate P disposed on the image plane IP of the projection optical system. The first imaging optical system K1 forms the intermediate image of the mask pattern on the intermediate imaging surface MP based on the light from the mask M. FIG. The second imaging optical system K2 forms an image of the mask pattern on the glass substrate P based on the light from this intermediate image. As a mechanism for adjusting the focus position, the focus correction optical system 70 constituted by two wedge-shaped lenses corrects the focus by moving one wedge-shaped lens in the direction perpendicular to the optical axis (Y direction). As a mechanism for adjusting the magnification, the magnification correction optical system 80 is composed of three lenses, and has opposing concave and convex X cylindrical surfaces, and similarly concave and convex Y cylindrical surfaces. By changing the spacing of the concave and convex cylindrical surfaces that are opposed to each other, the vertical and horizontal magnifications are independently corrected (Japanese Patent Laid-Open No. 2010-39347).

However, when there are many correction optical systems, it becomes a factor which increases the cost of an exposure apparatus by increasing glass material cost and processing cost. In addition, in the projection optical system of high NA (for example, NA 0.12 or more), since the spread of the light beam becomes large, the space in the projection optical unit is reduced. For this reason, the high-NA projection optical system has a problem in that the correction mechanism cannot be arranged or a restriction occurs in the place where it can be arranged.

This invention provides the optical system which can adjust a focus and magnification independently by the structure with few lenses in view of the said subject.

An optical system according to one aspect of the present invention, which achieves the above object, is disposed in an optical path from an object plane to an image plane, and adjusts the magnification and focus of a projection optical system that projects an image of an object disposed on the object plane onto the image plane. As an optical system to say,

A first optical element having a plane orthogonal to the optical axis of the projection optical system and a curved surface opposite the plane;

A second optical element having a curved surface opposite the curved surface of the first optical element,

A third optical element having a cylindrical surface having a bus bar in a first direction orthogonal to the optical axis of the projection optical system,

A fourth optical element having a busbar in the first direction and having a cylindrical surface opposite to the cylindrical surface of the third optical element, and a plane orthogonal to the optical axis of the projection optical system on a surface opposite the cylindrical surface;

And,

The second optical element has an inclined plane having a gradient with respect to the first direction on the opposite surface of the curved surface,

The third optical element has an inclined plane opposite to the inclined plane of the second optical element and parallel to the inclined plane of the second optical element on an opposite surface of the cylindrical surface.

Moreover, the exposure apparatus which concerns on another aspect of this invention is an exposure apparatus which has a projection optical system which projects the pattern of a mask on a board | substrate,

The projection optical system includes the optical system.

In addition, a device manufacturing method according to another aspect of the present invention,

Exposing the substrate to which the photosensitive agent is applied by the exposure apparatus;

It has a process of developing the said photosensitive agent.

According to the present invention, it is possible to provide an optical system capable of independently adjusting the focus and the magnification by the configuration in which the number of lenses is small.

Other features of the present invention will become more apparent from the following description of specific embodiments (with reference to the accompanying drawings).

1 is a diagram illustrating a configuration of an exposure apparatus having a correction optical system according to a first embodiment.
FIG. 2 is a diagram showing a projection optical unit having a correction optical system of the first embodiment. FIG.
3 is a diagram illustrating a correction optical system according to the first embodiment.
4A to 4F are diagrams showing a magnification correction method by the correction optical system of the first embodiment.
5A to 5F show a focus correction method by the correction optical system of the first embodiment.
FIG. 6 shows a correction optical system according to a second embodiment; FIG.
7A to 7F are diagrams showing a magnification correction method by the correction optical system of the second embodiment.
8 is a flowchart of an exposure method using an exposure apparatus having a correction optical system according to the first embodiment.
9 is a diagram illustrating a configuration of a projection optical unit constituting a projection optical system of a conventional exposure apparatus.

DETAILED DESCRIPTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the component described in this embodiment is an illustration to the last, The technical scope of this invention is determined by the claim, and is not limited by the following individual embodiment.

An optical system (hereinafter referred to as a "correction optical system") according to an embodiment of the present invention described below is disposed in an optical path from an object plane to an image plane, and projects an image of an object disposed on the object plane onto an image plane. Correct (adjust) magnification and focus. The correction optical system has, for example, four optical elements (lenses) formed of the same material (glass material). The first optical element has a plane orthogonal to the optical axis of the projection optical system and a curved surface opposite the plane. The second optical element has a curved surface opposite the curved surface of the first optical element. The third optical element has a cylindrical surface having a bus bar in a first direction orthogonal to the optical axis direction of the projection optical system. The fourth optical element has a cylindrical surface in the first direction and faces a cylindrical surface of the third optical element, and a plane perpendicular to the optical axis of the projection optical system on the opposite surface of the cylindrical surface. Here, the 2nd optical element has the inclined plane which has a gradient with respect to a 1st direction on the opposite surface of a curved surface, and the 3rd optical element is a 2nd optical element on the opposite surface of the cylindrical surface which opposes a 2nd optical element. Has an inclined plane parallel to the inclined plane.

In the following 1st Embodiment, the curved surface of a 1st optical element has a bus bar in the 2nd direction (X-axis direction) orthogonal to the optical axis direction (Z-axis direction) and 1st direction (Y-axis direction) of a projection optical system. The case where it is comprised as a concave cylindrical surface is demonstrated. In addition, the case where the curved surface of a 2nd optical element is comprised as a convex cylindrical surface which has a bus bar in a 2nd direction (X direction) is demonstrated as an example. Moreover, the structure of a cylindrical surface may comprise a convex cylindrical surface in the curved surface of a 1st optical element, and may comprise a concave cylindrical surface in the curved surface of a 2nd optical element.

In addition, in 2nd Embodiment, the case where the curved surface of a 1st optical element is comprised as a concave spherical surface, and the curved surface of a 2nd optical element is comprised as a convex spherical surface is demonstrated as an example. In addition, the structure of a spherical surface may comprise a convex spherical surface in the curved surface of a 1st optical element, and may comprise a concave spherical surface in the curved surface of a 2nd optical element.

(1st embodiment)

1 is a perspective view schematically showing the entire configuration of an exposure apparatus EE having a correction optical system according to a first embodiment of the present invention. 2 is a view showing a configuration of a projection optical unit, focusing on one typical projection optical unit of a plurality of projection optical units PL1 to PL5 (PL4 not shown) constituting the projection optical system PO of the exposure apparatus EE. to be.

1 and 2, the Y-axis is set along the direction in which the mask (original plate) M on which a predetermined circuit pattern is formed and the glass substrate P on which the resist is applied, that is, the scanning direction (indicated by the white arrows in FIG. 1). . In addition, the X axis is set along the direction orthogonal to the Y axis in the plane of the mask M. FIG. The Z axis is set along the normal direction of the mask (original plate) M and the glass substrate P (the optical axis direction of the projection optical system PO). The X axis is orthogonal to the Y and Z axes, and the Y axis is orthogonal to the X and Z axes. The XY plane constituted by the X axis and the Y axis is orthogonal to the Z axis.

An exposure apparatus scans the illumination system IL, the projection optical system PO, the mask stage MS which scans the mask M arrange | positioned at the object surface OP of the projection optical system PO, and the substrate stage which scans the glass substrate P arrange | positioned at the imaging surface IP of the projection optical system PO. PS is provided. The mask stage MS is movable by the mask drive mechanism, and the substrate stage PS is movable by the substrate drive mechanism. The mask pattern of the mask M with respect to the glass substrate P by moving the mask M hold | maintained on the mask stage MS and the glass substrate P hold | maintained by the substrate stage PS integrally in the same direction (for example, Y direction). Scanning exposure can be performed.

The illumination system IL illuminates the plurality of circular arc-shaped regions 11 arranged in the X-direction on the mask M in a substantially uniform illuminance. The illumination system IL is equipped with the light source 1, the optical fiber 2, and the illumination optical system 3. As shown in FIG. As a light source 1, a mercury lamp is comprised, for example, and a part of the output wavelength of a mercury lamp, such as i, h, g line | wire, is used as exposure light. The optical fiber 2 splits the light emitted from the light source 1 into plural (a total of five in FIG. 1) and guides the light to a predetermined position. The illumination optical system 3 has a role of obtaining a desired illuminance distribution on the mask M, such as condensing light emitted from the optical fiber 2.

Light from each illumination region on the mask M enters the projection optical system PO including a plurality of projection optical units PL arranged along the X direction so as to correspond to each illumination region. The light via the projection optical system PO is guided on the glass substrate P supported in parallel with the XY plane on the substrate stage PS to form a mask pattern image. The projection optical unit PL constituting the projection optical system PO includes the first imaging optical system K1 and the second imaging optical system K2. The first imaging optical system K1 forms the intermediate image of the mask pattern on the intermediate imaging surface MP based on the light from the mask M. FIG. The 2nd imaging optical system K2 forms the sizing phase (secondary image) of a mask pattern on the glass substrate P based on the light from this intermediate | middle image. In the vicinity of the formation position of the intermediate image of the mask pattern, the field of view aperture FS that defines the viewing area (lighting area) of the projection optical unit PL on the mask M and the projection area (exposure area) of the projection optical unit PL on the glass substrate P. Is installed. In addition, when illumination system IL is equipped with the visual field stop and the illumination area | region on mask M is defined by this visual field stop, visual field stop FS can also be abbreviate | omitted.

The 1st imaging optical system K1 is the 1st planar mirror 13, the 1st concave mirror 14, and the 1st convex surface mirror which were arrange | positioned in order from the object surface side to the optical path from object surface OP to intermediate | middle imaging surface MP. 15), a second concave mirror 16, and a second planar mirror 17. The light path between the object plane OP and the first plane mirror 13 and the light path between the second plane mirror 17 and the intermediate image plane MP are parallel. The plane including the mirror plane of the first plane mirror 13 and the plane including the mirror plane of the second plane mirror 17 form an angle of 90 degrees with respect to each other. In FIG. 2, although the 1st planar mirror 13 and the 2nd planar mirror 17 are comprised separately, the 1st planar mirror 13 and the 2nd planar mirror 17 may be integrally formed. 2, although the 1st concave mirror 14 and the 2nd concave mirror 16 are comprised separately, the 1st concave mirror 14 and the 2nd concave mirror 16 are integral. It may consist of.

On the other hand, the 2nd imaging optical system K2 is the 3rd planar mirror 18, the 3rd concave mirror 19, and the 2nd convex surface which were arrange | positioned in order from the object surface side in the optical path from intermediate | middle imaging surface MP to the imaging surface IP. A mirror 20, a fourth concave mirror 21, and a fourth planar mirror 22. The optical path between the intermediate image plane MP and the third planar mirror 18 and the optical path between the fourth planar mirror 22 and the second image plane IP are parallel. The plane containing the mirror surface of the 3rd planar mirror 18 and the plane containing the mirror surface of the 4th planar mirror 22 make an angle of 90 degrees with each other. In FIG. 2, although the 3rd planar mirror 18 and the 4th planar mirror 22 are comprised separately, the 3rd planar mirror 18 and the 4th planar mirror 22 may be integrally formed. In addition, although the 3rd concave mirror 19 and the 4th concave mirror 21 are comprised separately in FIG. 2, the 3rd concave mirror 19 and the 4th concave mirror 21 are integral. It may consist of.

(Compensation optical system)

In the optical path between the second planar mirror 17 and the intermediate imaging surface MP, a focus magnification correction optical system 40 (correction optical system) is provided as an optical system for independently correcting the focus and the magnification. 3 is a diagram illustrating a configuration of the focus magnification correction optical system 40 (correction optical system). The focus magnification correction optical system 40 (correction optical system) is an optical element, for example, four lenses of the first lens 41, the second lens 42, the third lens 43, and the fourth lens 44. Has

The first lens image surface 41a is a plane parallel to the XY plane. Here, the Y direction is a direction parallel to the scanning direction of the mask M, and the X direction is a direction perpendicular to the normal direction of the mask M (optical axis of the projection optical system PO: Z axis direction) and the scanning direction of the mask M (Y direction). to be. The normal direction of the mask M (optical axis of the projection optical system PO: Z axis direction) is perpendicular to the XY plane. The first lens lower surface 41b is a concave cylindrical surface having a busbar in an X direction perpendicular to the normal direction of the mask M (optical axis of the projection optical system PO: Z axis direction) and the scanning direction of the mask M (Y direction). .

The second lens upper surface 42a is a convex cylindrical surface having a bus bar in the X direction, and the second lens lower surface 42b is an inclined plane having a gradient in the Y direction with respect to the XY plane.

The third lens upper surface 43a is an inclined plane having a gradient in the Y direction with respect to the XY plane, and the third lens lower surface 43b is a concave cylindrical surface having a busbar in the Y direction.

The fourth lens upper surface 44a is a convex cylindrical surface having a bus bar in the Y direction, and the fourth lens lower surface 44b is a plane parallel to the XY plane.

The curvature of the concave cylindrical surface of the first lens lower surface 41b and the curvature of the convex cylindrical surface of the second lens upper surface 42a are substantially the same (first curvature). The first lens lower surface 41b and the second lens upper surface 42a are opposed to each other with an air gap of, for example, 5 to 20 mm. The curvature of the concave cylindrical surface of the third lens lower surface 43b and the curvature of the convex cylindrical surface of the fourth lens upper surface 44a are substantially the same (second curvature). The third lens lower surface 43b and the fourth lens upper surface 44a face each other with an air gap of, for example, 5 to 20 mm. In addition, the inclined plane of the lower surface of the second lens 42b and the inclined plane of the third lens upper surface 43a are parallel to each other and face each other with an air gap of 1 mm to 10 mm, for example.

The 1st lens 41 was equipped with the mechanism (not shown) which a position changes in a Z-axis direction, and enabled the Y magnification correction of the projection optical unit PL. Moreover, the 4th lens 44 was equipped with the mechanism (not shown) which changes a position in a Z-axis direction, and made X magnification correction of the projection optical unit PL. Moreover, the 3rd lens 43 was equipped with the mechanism (not shown) which changes a position in a Y-axis direction (1st direction), and enabled the focus correction of the projection optical unit PL. The distance between the first lens 41 and the second lens 42 can be adjusted by the movement of the first lens 41 in the optical axis direction of the projection optical system. In addition, the space | interval of the 3rd lens 43 and the 4th lens 44 can be adjusted by the movement of the 4th lens 44 in the optical-axis direction of a projection optical system.

(Phase Shift Correction Optical System)

The phase shift correction optical system 60 is provided in the optical path between the intermediate imaging surface MP and the second planar mirror 18 in FIG. 2. The phase shift correction optical system 60 is comprised including two parallel plate glass. One of two parallel plate glass is equipped with the mechanism rotated about an X-axis, and is comprised so that the phase shift of a Y-axis direction (1st direction) can be corrected. Moreover, the other is equipped with the mechanism rotated around a Y-axis, and is comprised so that the phase shift of an X-axis direction (2nd direction) can be corrected.

As described above, the mask pattern formed on the mask M is illuminated with almost uniform illuminance by the illumination light (exposure light) from the illumination system IL. From the mask pattern formed in each illumination region on the mask M, the light traveling along the -Z direction is the first plane mirror 13, the first concave mirror 14, the first convex mirror 15, and the first light. It is reflected in the order of the 2 concave mirror 16 and the 2nd planar mirror 17. FIG. Thereafter, the first lens 41, the second lens 42, the third lens 43, and the fourth lens 44 constituting the focus magnification correction optical system 40 pass through the intermediate image plane MP. An intermediate image of the mask pattern is formed on the (primary imaging surface). The visual field stop FS is provided on the intermediate | middle imaging surface MP (primary imaging surface), and the light beam outside a visual field is interrupted | blocked. In addition, the horizontal magnification in the X direction of the intermediate phase is +1 times, and the horizontal magnification in the Y direction is -1 times.

The light propagated along the -Z direction from the intermediate image of the mask pattern formed on the intermediate imaging surface MP (primary imaging surface) passes through the phase shift correction optical system 60, and then the third planar mirror 18 and the third concave. The surface mirror 19, the second convex mirror 20, the fourth concave mirror 21, and the fourth planar mirror 22 are reflected in this order. The light then proceeds along the -Z direction and forms an image (secondary image) of the mask pattern with the imaging surface IP (secondary imaging surface). Here, the horizontal magnification in the X direction of the secondary phase and the horizontal magnification in the Y direction are both +1 times. That is, the mask pattern image formed on the glass substrate P via the projection optical unit PL is an equal magnification normal phase, and the projection optical unit PL comprises the equal magnification system.

The projection optical unit PL in the present embodiment constitutes an equal magnification system, but the projection optical unit PL can be configured as any of an equal magnification optical system, an enlarged imaging optical system, and a reduced imaging optical system. However, it is preferable that the projection optical unit PL is configured as an equal magnification imaging optical system, and it is preferable that the chief rays of light are both parallel in the object plane side and the image plane side, that is, have both telecentricity in both the object plane and the image plane.

As described above, the mask pattern image formed on the glass substrate P via the projection optical unit PL is an equal magnification. Therefore, the projection optical system PO comprised by the several projection optical unit PL forms the mask pattern image of the grain-shape of equal magnification on the glass substrate P as a whole. The desired scanning exposure can be performed by moving the mask M held on the mask stage MS and the glass substrate P held on the substrate stage PS integrally along the same direction (Y direction).

(Magnification adjustment of the projection optical unit PL)

Next, the magnification adjustment of the projection optical unit PL, ie, the adjustment of the projection magnification from the mask M to the glass substrate P, will be described. As described above, the projection optical unit PL constituting the projection optical system PO is manufactured so as to form an equal magnification of the projected image. However, when the projection optical system PO is assembled, an error in the magnification is obtained in each projection optical unit PL due to manufacturing error or the like. May occur. In addition, different magnification errors may occur in the X direction and the Y direction by pressing the multilayer onto the substrate or by using the mask (original plate) a plurality of times to generate the stretch. In this case, magnification adjustment is performed in each projection optical unit PL in order to make the magnification of each projection optical unit PL equal.

4A and 4B are diagrams showing the focus magnification correction optical system 40 in the nominal state showing the state serving as a reference. 4A is a diagram illustrating a YZ cross section of the focus magnification correction optical system 40, and FIG. 4B is a diagram illustrating an XZ cross section of the focus magnification correction optical system 40.

The Y magnification adjustment of the projection optical unit PL is performed by changing the Z direction position of the first lens 41 constituting the focus magnification correction optical system 40. 4C and 4D show the focus magnification correction optical system 40 in a state where the position of the first lens 41 is changed in the + Z direction and the Y magnification is positively changed (enlarged). 4C is a diagram illustrating a YZ cross section of the focus magnification correction optical system 40, and FIG. 4D is a diagram illustrating an XZ cross section of the focus magnification correction optical system 40. As shown in FIGS. 4C and 4D, when the position of the first lens 41 is changed in the + Z direction, the distance between the first lens 41 and the second lens 42 is enlarged, and each projection optical unit The Y magnification of PL changes (magnifies) positively (FIG. 4C). The X magnification of each projection optical unit PL does not change (FIG. 4D). On the contrary, when the position of the first lens 41 is changed in the -Z direction, the distance between the first lens 41 and the second lens 42 is reduced, and the Y magnification of each projection optical unit PL changes negatively (reduced). )do. Even when the position of the first lens 41 is changed in the -Z direction, the X magnification of each projection optical unit PL does not change.

The X magnification adjustment of the projection optical unit PL is performed by changing the Z direction position of the fourth lens 44 constituting the focus magnification correction optical system. 4E and 4F show the focus magnification correction optical system 40 in a state where the position of the fourth lens 44 is changed in the -Z direction and the X magnification is positively changed (enlarged). 4E is a diagram illustrating a YZ cross section of the focus magnification correction optical system 40, and FIG. 4F is a diagram illustrating an XZ cross section of the focus magnification correction optical system 40. As shown in Figs. 4E and 4F, when the position of the fourth lens 44 is changed in the -Z direction, the distance between the fourth lens 44 and the third lens 43 is enlarged, and each projection optical unit The X magnification of PL is changed (enlarged) to plus (FIG. 4F). The Y magnification of each projection optical unit PL does not change (FIG. 4E). On the contrary, when the position of the fourth lens 44 is changed in the + Z direction, the distance between the fourth lens 44 and the third lens 43 is reduced, and the X magnification of each projection optical unit PL changes negatively (reduced). )do. Even when the position of the fourth lens 44 is changed in the + Z direction, the X magnification of each projection optical unit PL does not change.

When the above-mentioned X magnification adjustment is performed in each of the projection optical units PL1 to PL5, a deviation occurs in the relative position in the X direction of the imaging position in the imaging plane IP of each of the projection optical units PL1 to PL5. In order to correct this shift of the relative position, it is necessary to adjust the X-direction position of the imaging position of the projection optical unit PL by the image shift correction optical system 60. Specifically, the X direction of the image forming position of each projection optical unit PL by rotating one of the two parallel flat glasses constituting the image shift correction optical system 60 around the Y axis and generating an image shift in the X direction. Adjust the position.

(Focus adjustment of projection optical unit PL)

Next, focus adjustment of projection optical unit PL is demonstrated. 5A and 5B are diagrams showing the focus magnification correction optical system 40 in the nominal state showing the state serving as a reference. 5A is a diagram illustrating a YZ cross section of the focus magnification correction optical system 40, and FIG. 5B is a diagram illustrating an XZ cross section of the focus magnification correction optical system 40. Moreover, the focus surface 23 has shown the focus position of the projection optical unit PL in a nominal state.

Focus adjustment of the projection optical unit PL is performed by changing the Y-direction position of the third lens 43 constituting the focus magnification correction optical system 40. That is, the third lens 43 is moved in a state where the inclined plane of the third lens upper surface 43a is parallel to the second lens 42 (the inclined plane of the second lens lower surface 42b). 5C and 5D show the focus magnification correction optical system 40 in a state where the position of the third lens 43 is changed in the -Y direction and the focus position is changed in the + Z direction. 5C is a diagram illustrating a YZ cross section of the focus magnification correction optical system 40, and FIG. 5D is a diagram illustrating an XZ cross section of the focus magnification correction optical system 40. As shown in Figs. 5C and 5D, when the position of the third lens 43 is changed in the -Y direction, the focus is changed in the + Z direction because the thickness of the glass through which the light passes is reduced. The focus surface 24 represents the focus position when the focus position on the focus surface 23 is changed in the + Z direction. On the contrary, when the position of the third lens 43 is changed in the + Y direction, since the thickness of the glass through which light passes increases, the focus is changed in the -Z direction.

When the position of the third lens 43 in the Y direction is changed, since the third lens lower surface 43b is a cylindrical surface having a bus bar in the Y direction, the third lens lower surface 43b with respect to the fourth lens upper surface 44a is not. The positional relationship does not change optically. Since the optical positional relationship between the third lens lower surface 43b and the fourth lens upper surface 44a does not change, only the focus can be independently corrected without affecting the X magnification.

In addition, when such focus correction is performed, the distance between the second lens lower surface 42b and the third lens upper surface 43a is changed. As a result, a phase shift in the Y direction occurs. In the case of FIG. 5C, the imaging position is changed in the + Z direction (+ DZ) and also changed (phase shift) in the -Y direction (-DY).

In order to correct this phase shift in the Y direction, it is necessary to perform phase shift correction by the phase shift correction optical system 60 at the time of focus correction. Specifically, the Y-direction position of the image forming position is adjusted by rotating one of the two parallel plate glasses constituting the image shift correction optical system 60 around the X axis and generating a phase shift in the Y direction.

In addition, focus adjustment is not limited to the said method, For example, in the state in which the inclined plane of the 3rd lens upper surface 43a is parallel with the 2nd lens 42 (the inclined plane of the 2nd lens lower surface 42b), The third lens 43 is moved in a direction parallel to the inclined plane of the third lens upper surface 43a. Simultaneously with this movement, the focus adjustment may be performed by moving the fourth lens 44 in the Z direction so that the gap between the fourth lens 44 and the third lens 43 is maintained. 5E and 5F show the focus magnification correction optical system 40 in a state in which the third lens 43 and the fourth lens 44 are simultaneously moved and the focus position is changed in the + Z direction. 5E and 5F, the third lens 43 is moved in a state where the inclined plane of the third lens upper surface 43a is parallel to the second lens 42 (the inclined plane of the second lens lower surface 42b). Let's do it. Simultaneously with this movement, the 4th lens 44 was moved to Z direction so that the space | interval of the 4th lens 44 and the 3rd lens 43 may be maintained.

5E is a diagram illustrating a YZ cross section of the focus magnification correction optical system 40, and FIG. 5F is a diagram illustrating an XZ cross section of the focus magnification correction optical system 40. As shown in FIGS. 5E and 5F, when the third lens 43 is moved obliquely upward, the focus changes in the + Z direction because the thickness of the glass through which the light passes decreases. The focus surface 24 shows the focus position when the focus is changed in the + Z direction. On the contrary, when the third lens 43 is moved obliquely downward, since the thickness of the glass through which the light passes increases, the focus is changed in the -Z direction. At this time, the movement direction of the third lens 43 is made parallel to the inclined plane of the third lens upper surface 43a (the inclined plane of the second lens lower surface 42b), whereby the second lens 42 and the third lens ( 43) is maintained. Therefore, the phase shift (-DY) in the Y direction as shown in FIG. 5C does not occur. In addition, by moving the fourth lens 44 in the + Z direction, the distance between the third lens lower surface 43b and the fourth lens upper surface 44a is also maintained. Therefore, enlargement of the X magnification as shown in FIG. 4F does not occur.

As mentioned above, although the structure of the correction optical system in this embodiment was demonstrated, it is not limited to the said structure, A various structure is possible. For example, the unevenness | corrugation of the cylindrical surface which opposes the focus magnification correction optical system 40 may change. Specifically, the first lens lower surface 41b may be determined as a convex cylindrical surface, and the second lens upper surface 42a may be determined as a concave cylindrical surface. The lower surface 43b of the third lens may be determined as a convex cylindrical surface, and the upper surface of the fourth lens 44a may be determined as a concave cylindrical surface.

The focus magnification correction optical system 40 is not limited between the second planar mirror 17 and the intermediate image plane MP, but can be disposed at other positions. For example, you may arrange | position between intermediate | middle imaging surface MP and the 3rd planar mirror 18, or between the 4th planar mirror 22 and the glass substrate P. FIG. In addition, although this embodiment mentioned the projection optical unit of the exposure apparatus as an example, the focus magnification correction optical system 40 can also be used also in the optical system of other uses.

(Exposure Method Using Exposure Device Having Correction Optical System)

Next, the exposure method using the exposure apparatus which has the correction optical system of this embodiment is demonstrated based on FIG. It is a flowchart of the exposure method using the exposure apparatus which has the correction optical system of 1st Embodiment of this invention.

As shown in FIG. 8, first, an unexposed glass substrate is carried in on the board | substrate stage in step S1 (substrate carrying in). Subsequently, in step S2, determination of whether or not to perform focus correction is performed based on a predetermined criterion. The judgment criteria are, for example, whether a predetermined time has elapsed since the last focus correction, replacement of the mask M, the number of sheets of the glass substrate P, the switching of the lot of the glass substrate P, and the like. When focus correction is performed (step S2; YES), the shift of the focus position of each projection optical unit is measured by the focus measuring mechanism mounted in each projection optical unit (step S3). Next, the third lens 43 of the focus magnification correction optical system 40 is moved in the Y direction so as to correct the shift in the measured focus position (step S4).

Subsequently, determination of whether magnification correction is performed or not is performed based on a predetermined judgment criterion (step S5). The judgment criterion is, for example, whether or not a predetermined time has elapsed since the last focus correction, the mask M is replaced, the number of sheets of the glass substrate P, the switching of the lot of the glass substrate P, and the like, as in the case of the focus correction implementation. . When performing magnification correction (S5; Yes), the magnification of the X direction and Y direction of a glass substrate is measured by the magnification measuring mechanism mounted in each projection optical unit (step S6). Next, the fourth lens 44 of the focus magnification correction optical system 40 is moved in the Z direction so as to correct the magnification in the measured X direction (step S7). Next, the first lens 41 of the focus magnification correction optical system 40 is moved in the Z direction so as to correct the magnification in the measured Y direction (step S8).

Next, the image shift correction required by changing the position of each lens of the focus magnification correction optical system 40 is performed by the image shift correction optical system 60 (step S9).

According to the above procedure, the deviation of the measured focus position, the X magnification and the Y magnification can be corrected without generating aberrations. In the next step, the pattern of the mask M is pressed against the glass substrate P by exposure (step S10).

After the completion of the exposure, the exposed glass substrate P on the substrate stage PS is carried out (step S11), and it is determined whether all of the glass substrates P to be processed have been exposed (step S12). If the unexposed board | substrate remains, it returns to step S1, the new unexposed glass substrate P is carried in, and the said process is repeated. It ends when all glass substrates are exposed.

As mentioned above, although the exposure method in this embodiment was demonstrated, it is not limited to the said structure, Various structures are possible. For example, instead of performing the focus measurement in step S3, the focus correction target value may be calculated by predictive calculation, and the focus correction in step S4 may be performed by the correction target value.

In addition, instead of performing magnification measurement in step S6, you may calculate a magnification correction target value by prediction calculation, and you may perform magnification correction of step S7, S8 by the magnification correction target value. Further, the substrate temperature may be measured, and the magnification correction may be performed by calculating the elongation amount of the substrate based on the measurement result. Moreover, it is also possible to change the correction order of X magnification correction S7 and Y magnification correction S8, and to make Y magnification correction S7 and X magnification correction S8.

In addition, after performing the lens movement for the correction which comprises the focus magnification correction optical system 40, you may make it confirm the measurement of the result of focus correction and magnification correction. For example, the focus measurement may be performed immediately after the third lens 43 is moved in step S4 to check whether the focus changes as desired. In addition, you may make a magnification measurement immediately after moving the 4th lens 44 and the 1st lens 41 in step S7 and step S8, and may confirm whether the X magnification and Y magnification changed as desired.

(Second Embodiment)

Next, the exposure apparatus of 2nd Embodiment of this invention is demonstrated. The exposure apparatus of 2nd Embodiment replaces the focus magnification correction optical system 40 of FIG. 2 with the focus magnification correction optical system 50 shown in FIG. 6 is a diagram illustrating a configuration of the focus magnification correction optical system 50 (correction optical system).

The focus magnification correction optical system 50 is provided in, for example, an optical path between the second planar mirror 17 and the intermediate image plane MP.

The focus magnification correction optical system 50 has four lenses, for example, a first lens 51, a second lens 52, a third lens 53, and a fourth lens 54.

The first lens upper surface 51a is a plane parallel to the XY plane, and the first lens lower surface 51b is a concave spherical surface. The second lens upper surface 52a is a convex spherical surface, and the second lens lower surface 52b is an inclined plane having a gradient (gradient of the third inclination angle) in the Y direction with respect to the XY plane.

The third lens image surface 53a is an inclined plane having a gradient (gradient of the fourth inclination angle) in the Y direction with respect to the XY plane. The third lens lower surface 53b is a concave cylindrical surface having a bus bar in the Y direction. The fourth lens upper surface 54a is a convex cylindrical surface having a busbar in the Y direction, and the fourth lens lower surface 54b is a plane parallel to the XY plane.

The curvature of the spherical surface of the first lens lower surface 51b and the curvature of the spherical surface of the second lens upper surface 52a are substantially the same (first curvature), and the first lens lower surface 51b and the second lens upper surface 52a are For example, they oppose with the air space of 5-20 mm.

The curvature of the cylindrical surface of the third lens lower surface 53b and the curvature of the cylindrical surface of the fourth lens upper surface 54a are substantially the same (second curvature). The third lens lower surface 53b and the fourth lens upper surface 54a face each other with an air gap of, for example, 5 to 20 mm. Incidentally, the inclined plane of the second lens lower surface 52b and the inclined plane of the third lens upper surface 53a are parallel to each other and face each other with an air gap of 1 mm to 10 mm, for example.

The 1st lens 51 and the 4th lens 54 were equipped with the mechanism (not shown) which changes a position in a Z-axis direction, and made X magnification correction and Y magnification correction of the projection optical unit PL. The third lens 53 also has a mechanism (not shown) whose position is changed in the Y-axis direction, and enables focus correction of the projection optical unit PL.

(Magnification adjustment of the projection optical unit PL)

Next, the magnification adjustment of projection optical unit PL is demonstrated. 7A and 7B are diagrams showing the focus magnification correction optical system 50 in the nominal state showing the state serving as a reference. FIG. 7A is a diagram illustrating a YZ cross section of the focus magnification correction optical system 50, and FIG. 7B is a diagram illustrating an XZ cross section of the focus magnification correction optical system 50.

The X magnification adjustment and the Y magnification adjustment of the projection optical unit PL are performed by changing the Z direction positions of the first lens 51 and the fourth lens 54 constituting the focus magnification correction optical system 50. 7C and 7D show the focus magnification correction optical system 50 in a state where the positions of the first lens 51 and the fourth lens 54 are changed in the + Z direction, and the X magnification and the Y magnification are changed to plus. ). 7C is a diagram illustrating a YZ cross section of the focus magnification correction optical system 50, and FIG. 7D is a diagram illustrating an XZ cross section of the focus magnification correction optical system 50. As shown in FIGS. 7C and 7D, when the position of the first lens 51 is changed in the + Z direction, the distance between the first lens lower surface 51b and the second lens upper surface 52a is enlarged, and each projection The X magnification and the Y magnification of the optical unit PL are both changed to plus. However, at the same time, since the position of the fourth lens 54 is changed in the + Z direction, the distance between the third lens lower surface 53b and the fourth lens upper surface 54a is reduced, and the X magnification is changed to negative (FIG. 7D). ). If the fourth lens 54 is moved so that the positive X magnification due to the movement of the first lens 51 is canceled by the negative X magnification due to the movement of the fourth lens 54, only the Y magnification changes to positive. This can be done (Fig. 7c).

By the reverse movement, when the positions of the first lens 51 and the fourth lens 54 are changed in the -Z direction, the Y magnification of the projection optical unit PL is negatively changed.

The X magnification adjustment of the projection optical unit PL is performed by changing the Z direction position of the fourth lens 54 constituting the focus magnification correction optical system 50. 7E and 7F show the focus magnification correction optical system 50 in a state where the position of the fourth lens 54 is changed in the -Z direction and the X magnification is changed to positive. FIG. 7E is a diagram showing a YZ cross section of the focus magnification correction optical system 50, and FIG. 7F is a diagram showing an XZ cross section of the focus magnification correction optical system 50. As shown in FIGS. 7E and 7F, when the position of the fourth lens 54 is changed in the -Z direction, the distance between the third lens lower surface 53b and the fourth lens upper surface 54a is enlarged, and each projection is performed. The X magnification of the optical unit PL is changed to positive (FIG. 7F). The Y magnification of each projection optical unit PL does not change (FIG. 7E). On the contrary, when the position of the fourth lens 54 is changed in the + Z direction, the X magnification of the projection optical unit PL is changed to negative. Even when the position of the fourth lens 54 is changed in the + Z direction, the Y magnification of each projection optical unit PL does not change.

(Focus adjustment of projection optical unit PL)

Next, focus adjustment of projection optical unit PL is demonstrated. Focus adjustment of the projection optical unit PL is performed by changing the Y-direction position of the third lens 53 constituting the focus magnification correction optical system 50.

When the position of the third lens 53 is changed in the -Y direction, since the thickness of the glass through which the light passes is reduced, the focus is changed in the + Z direction as shown in FIG. 5C, for example. On the contrary, when the position of the third lens 53 is changed in the + Y direction, since the thickness of the glass through which the light passes increases, the focus is changed in the -Z direction.

In addition, the focus adjustment moves the third lens 53 in a parallel direction with respect to the inclined plane of the third lens upper surface 53a, while maintaining the distance between the third lens 53 and the fourth lens 54. You may carry out by moving to Z direction. By moving the third lens 53 in a direction parallel to the inclined surface of the upper surface of the third lens 53 (the inclined surface of the lower surface of the second lens 52b), the second lens 52 and the third lens 53 are moved. The interval of is maintained. Therefore, the phase shift (-DY) in the Y direction as shown in FIG. 5C does not occur. In addition, by moving the fourth lens 54 in the + Z direction, the distance between the third lens lower surface 53b and the fourth lens upper surface 54a is also maintained. Therefore, enlargement of the X magnification as shown in FIG. 4F does not occur.

As mentioned above, although the structure of the correction optical system in this embodiment was demonstrated, it is not limited to the said structure, A various structure is possible. For example, as for the focus magnification correction optical system 50, the unevenness | corrugation of the opposing spherical surface and the cylindrical surface may change. Specifically, the first lens lower surface 51b may be a convex spherical surface, and the second lens upper surface 52a may be a concave spherical surface, and the third lens lower surface 53b may be a convex cylindrical surface and a fourth lens upper surface 54a. It may be determined by this concave cylindrical surface.

The focus magnification correction optical system 50 is not limited between the second planar mirror 17 and the intermediate image plane MP, but can be disposed at other positions. Specifically, you may arrange | position between intermediate | middle imaging surface MP and the 3rd planar mirror 18, or between the 4th planar mirror 22 and the glass substrate P. FIG.

In addition, although this embodiment demonstrated the projection optical unit of the exposure apparatus as an example, the focus magnification correction optical system 50 can also be used also in the optical system used for other objectives.

(Exposure Method Using Exposure Device Having Correction Optical System)

Next, the exposure method using the exposure apparatus which has the focus magnification correction optical system 50 (correction optical system) of 2nd Embodiment is demonstrated. The exposure method using the exposure apparatus of 2nd Embodiment becomes the flow of a process basically the same as the exposure method demonstrated in 1st Embodiment. However, in each step of the focus correction of step S4, the X magnification correction of step S7, and the Y magnification correction of step S8, the lens constituting the focus magnification correction optical system 50 described in the present embodiment is moved, and the focus correction, X Magnification correction and Y magnification correction are performed. By such correction, the deviation of the measured focus position, the deviation of the X magnification and the Y magnification can be independently corrected without generating an aberration. Also in the exposure method which concerns on this embodiment, it is possible to apply the deformation | transformation of the deformation | transformation of the exposure method demonstrated in 1st Embodiment.

According to the first and second embodiments described above, a correction optical system capable of independently correcting the focus and the vertical and horizontal magnifications can be provided.

(Third Embodiment)

Next, the manufacturing method of a device (liquid crystal display device etc.) is demonstrated as 3rd Embodiment of this invention. A liquid crystal display device is manufactured by going through the process of forming a transparent electrode. The process of forming a transparent electrode includes the process of apply | coating a photosensitive agent to the glass substrate in which the transparent conductive film was deposited, the process of exposing the glass substrate to which the photosensitive agent was applied using the above-mentioned exposure apparatus, and the process of developing a glass substrate. .

The device manufacturing method using the exposure apparatus mentioned above is suitable also for manufacture of devices, such as a semiconductor device, in addition to a liquid crystal display device. The method may include exposing the substrate to which the photosensitive agent is applied, using the exposure apparatus, and developing the exposed substrate. The device manufacturing method may also include other well-known processes (oxidation, film formation, deposition, doping, planarization, etching, resist stripping, dicing, bonding, packaging, and the like).

While the present invention has been described with reference to specific embodiments, it is to be understood that the invention is not limited to the specific embodiments thereof. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims (13)

An optical system arranged on an optical path from an object plane to an image plane, the optical system for adjusting the magnification and focus of a projection optical system projecting an image of an object disposed on the object plane to the image plane,
A first optical element having a plane orthogonal to the optical axis of the projection optical system and a curved surface opposite the plane;
A second optical element having a curved surface opposite the curved surface of the first optical element,
A third optical element having a cylindrical surface having a bus bar in a first direction orthogonal to the optical axis of the projection optical system,
A fourth optical element having a busbar in the first direction and having a cylindrical surface opposite to the cylindrical surface of the third optical element, and a plane orthogonal to the optical axis of the projection optical system on a surface opposite the cylindrical surface;
And,
The second optical element has an inclined plane having a gradient with respect to the first direction on an opposite surface of the curved surface of the second optical element,
The third optical element has an inclined plane opposite to the inclined plane of the second optical element and parallel to the inclined plane of the second optical element on an opposite surface of the cylindrical surface. The method of claim 1,
An optical system for adjusting the magnification of the projection optical system by adjusting at least one of the interval between the first optical element and the second optical element and the interval between the third optical element and the fourth optical element. The method of claim 1,
An optical system for adjusting the focus of the projection optical system by moving the third optical element in a state in which the inclined plane of the third optical element is parallel to the inclined plane of the second optical element. The method of claim 1,
The space | interval of a said 1st optical element and a said 2nd optical element is adjustable by the movement of the said 1st optical element in the optical-axis direction of the said projection optical system,
The interval between the third optical element and the fourth optical element can be adjusted by the movement of the fourth optical element in the optical axis direction of the projection optical system,
The magnification of the projection optical system is adjusted by the movement of the first optical element and the movement of the fourth optical element. The method of claim 1,
The third optical element is movable in a direction in which the inclined plane of the third optical element is parallel to the inclined plane of the second optical element,
When the third optical element is moved, the fourth optical element is movable in the optical axis direction of the projection optical system so as to maintain a distance between the third optical element and the fourth optical element,
The focus of the projection optical system is adjusted by the movement of the third optical element and the movement of the fourth optical element. The method of claim 1,
The curved surface of the first optical element is a concave cylindrical surface having a first curvature and having a bus bar in a second direction perpendicular to the optical axis direction and the first direction of the projection optical system,
The curved surface of the second optical element is a convex cylindrical surface having the first curvature and having a bus bar in the second direction. The method of claim 1,
The curved surface of the first optical element is a concave spherical surface having a first curvature,
The curved surface of the second optical element is an optical system having a convex spherical surface having the first curvature. The method of claim 1,
The curved surface of the first optical element is a convex cylindrical surface having a first curvature and having a bus bar in a second direction perpendicular to the optical axis direction and the first direction of the projection optical system,
The curved surface of the second optical element is a concave cylindrical surface having the first curvature and having a bus bar in the second direction. The method of claim 1,
The curved surface of the first optical element is a convex spherical surface having a first curvature,
The curved surface of the second optical element is an optical system having a concave spherical surface having the first curvature. The method of claim 1,
The cylindrical surface of the third optical element is a concave cylindrical surface having a second curvature,
The cylindrical surface of the fourth optical element is an optical system having a convex cylindrical surface having the second curvature. The method of claim 1,
The cylindrical surface of the third optical element is a convex cylindrical surface having a second curvature,
The cylindrical surface of the fourth optical element is an optical system having a concave cylindrical surface having the second curvature. An exposure apparatus having a projection optical system for projecting a pattern of a mask onto a substrate,
The said projection optical system is provided with the optical system of Claim 1. A device manufacturing method comprising:
Exposing the board | substrate with which the photosensitizer was apply | coated with the exposure apparatus of Claim 12,
A device manufacturing method having a step of developing the photosensitive agent.

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