JP2011014662A - Exposure device, exposing method and manufacturing method of device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly correct a spherical aberration of a projection optical system, and to transfer the pattern of a mask correctly onto a photosensitive substrate.SOLUTION: An exposure device, which carries out projection exposure of the pattern of a mask (M) onto the photosensitive substrate (W) via a projection optical system (PL), includes a mask stage (MS) which holds the mask movably in the direction of the optical axis (AX); an optical path length variable member (1) which has a medium part, being located near the mask in the optical path of the projection optical system and consisting of a medium having a refractive index different from that of the gas in the optical path and changes the optical path length along the direction (Z direction) parallel with the optical axis of the medium part; and a control unit (CR) which interlocks the change in the optical path length of the medium part in the optical path length variable member with the movement of the mask stage in the direction of the optical axis for correcting the higher order spherical aberrations of the projection optical system.

Description

  The present invention relates to an exposure apparatus, an exposure method, and a device manufacturing method. More specifically, the present invention relates to correction (adjustment) of spherical aberration of a projection optical system mounted on an exposure apparatus.

  For example, when a device such as a semiconductor element, an image sensor, a liquid crystal display element, or a thin film magnetic head is manufactured by a lithography process, a pattern of a mask (or a reticle or the like) is applied to a photosensitive substrate (a wafer or a plate coated with a resist). An exposure apparatus that performs projection exposure is used. In this type of exposure apparatus, a projection optical system having a relatively large numerical aperture and good optical performance is designed in order to faithfully project a mask pattern image onto a photosensitive substrate with high resolution.

  However, in the actually produced projection optical system, various aberrations remain due to various factors, unlike the designed optical performance. In particular, when spherical aberration remains in the projection optical system having a relatively large numerical aperture, it becomes difficult to form a clear image of the mask pattern on the photosensitive substrate. Therefore, a technique has been proposed in which spherical aberration varying means including two wedge prisms is arranged on the mask side of the projection optical system, and spherical aberration is corrected by the action of the spherical aberration varying means (for example, Patent Document 1). reference).

JP-A-2-166719

  In the prior art disclosed in Patent Document 1, low-order spherical aberration can be corrected, but high-order spherical aberration cannot be suppressed to a desired range. As a result, a fine pattern of the mask is accurately formed on the photosensitive substrate. It was difficult to transfer to

  The present invention has been made in view of the above-described problems, and is an exposure apparatus that can satisfactorily correct the spherical aberration of the projection optical system and can accurately transfer the mask pattern onto the photosensitive substrate. And an exposure method.

In order to solve the above problems, in the first embodiment of the present invention, in an exposure apparatus that projects and exposes a mask pattern onto a photosensitive substrate via a projection optical system,
A mask stage that holds the mask movably in the optical axis direction of the projection optical system;
In the optical path of the projection optical system, there is a medium part made of a medium having a refractive index different from that of the gas in the optical path disposed in the vicinity of the mask, and in a direction parallel to the optical axis of the medium part An optical path length variable member that changes the optical path length along the path,
In order to correct higher-order spherical aberration of the projection optical system, a control unit is provided for interlocking the change of the optical path length of the medium portion and the movement of the mask stage in the optical axis direction in the optical path length variable member. An exposure apparatus is provided.

In the second embodiment of the present invention, in an exposure apparatus for projecting and exposing a mask pattern onto a photosensitive substrate via a projection optical system,
A substrate stage for holding the photosensitive substrate movably in the optical axis direction;
A medium portion made of a medium having a refractive index different from that of the gas in the optical path, disposed in a position near the photosensitive substrate in the optical path of the projection optical system, and parallel to the optical axis of the medium portion; An optical path length variable member that changes the optical path length along the direction;
In order to correct higher-order spherical aberration of the projection optical system, a control unit is provided that interlocks the change in the optical path length of the medium portion with the movement of the substrate stage in the optical axis direction in the optical path length variable member. An exposure apparatus is provided.

In the third aspect of the present invention, in an exposure method for projecting and exposing a predetermined pattern onto a photosensitive substrate via a projection optical system,
In order to correct higher-order spherical aberration of the projection optical system, the pattern is arranged in the vicinity of the pattern in conjunction with the movement of the projection optical system in the optical axis direction, and is different from the gas in the optical path. There is provided an exposure method characterized by changing an optical path length along a direction parallel to the optical axis of a medium portion made of a refractive index medium.

In the fourth embodiment of the present invention, in an exposure method for projecting and exposing a predetermined pattern onto a photosensitive substrate via a projection optical system,
In order to correct higher-order spherical aberration of the projection optical system, the photosensitive substrate is disposed at a position in the vicinity of the photosensitive substrate in conjunction with the movement of the projection optical system in the optical axis direction. There is provided an exposure method characterized by changing an optical path length along a direction parallel to the optical axis of a medium portion made of a medium having a refractive index different from that of gas.

In the fifth embodiment of the present invention, using the exposure apparatus of the first embodiment or the second embodiment, an exposure process of exposing the pattern of the mask onto the photosensitive substrate;
Developing the photosensitive substrate to which the pattern has been transferred, and forming a mask layer having a shape corresponding to the pattern on the surface of the photosensitive substrate;
And a processing step of processing the surface of the photosensitive substrate through the mask layer.

  In the exposure apparatus according to one aspect of the present invention, along with the change in the optical path length of the medium portion in the optical path length variable member, the spherical aberration that occurs as the mask stage (and thus the pattern surface of the mask) moves in the optical axis direction. The spherical aberration of the projection optical system can be corrected (adjusted) satisfactorily using the difference from the generated spherical aberration, that is, the difference between two spherical aberrations having different properties. As a result, it is possible to accurately transfer the mask pattern onto the photosensitive substrate by using the projection optical system in which the spherical aberration is well corrected, and thus a good device can be manufactured.

It is a figure which shows schematically the structure of the exposure apparatus concerning embodiment of this invention. It is a figure which shows schematically the structure and arrangement | positioning of the optical path length variable member of FIG. It is a figure which shows a mode that a pattern surface is moved along an optical axis direction from the object surface of a projection optical system. It is a figure which shows typically the property of the spherical aberration which generate | occur | produces with the movement of the pattern surface of FIG. It is a figure which shows a mode that the thickness of the plane parallel plate arrange | positioned in the vicinity of the object plane of a projection optical system is changed. It is a figure which shows typically the property of the spherical aberration which generate | occur | produces with the thickness change of the plane parallel plate of FIG. It is a figure which shows that a property differs by the spherical aberration which arises with the movement of a pattern surface, and the spherical aberration which arises with the thickness change of a parallel plane plate. It is a figure which shows a mode that the spherical aberration of a projection optical system is correct | amended using the difference of the spherical aberration which arises with the movement of a pattern surface, and the spherical aberration which arises with the thickness change of a plane parallel plate. It is a figure which shows schematically the structure of the 1st modification of an optical path length variable member. It is a figure which shows schematically the structure of the 2nd modification of an optical path length variable member. It is a figure which shows schematically the principal part structure of another embodiment which has arrange | positioned the optical path length variable member in the vicinity of a wafer. It is a flowchart which shows the manufacturing process of a semiconductor device. It is a flowchart which shows the manufacturing process of liquid crystal devices, such as a liquid crystal display element.

  Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a drawing schematically showing a configuration of an exposure apparatus according to an embodiment of the present invention. In FIG. 1, the X axis and the Y axis are set to be orthogonal to each other in a plane parallel to the surface (transfer surface) of the wafer W, and the Z axis is set to the normal direction of the surface of the wafer W. More specifically, the XY plane is set horizontally and the + Z axis is set upward along the vertical direction.

  The exposure apparatus of FIG. 1 includes a light source LS, an illumination optical system IL, a mask stage MS, a projection optical system PL, a substrate stage WS, and a controller CR. As the light source LS, an ArF excimer laser light source that supplies light with a wavelength of 193 nm, a KrF excimer laser light source that supplies light with a wavelength of 248 nm, or the like can be used. The illumination optical system IL includes, for example, a spatial light modulation element (diffractive optical element), an optical integrator (homogenizer), a field stop, a condenser optical system, and the like.

  The illumination optical system IL illuminates a mask (reticle) M on which a pattern to be transferred is formed by exposure light (illumination light) emitted from the light source LS. In the case of a step-and-repeat exposure apparatus, the illumination optical system IL illuminates the entire rectangular pattern region of the mask M. In the case of a step-and-scan type exposure apparatus, the illumination optical system IL illuminates an elongated rectangular area along the X direction orthogonal to the Y direction, which is the scanning direction, out of the rectangular pattern area.

  The light transmitted through the pattern surface of the mask M forms a pattern image of the mask M in a unit exposure region of a wafer (photosensitive substrate) W coated with a photoresist, for example, via a projection optical system PL having a reduction magnification. . That is, in the unit exposure region of the wafer W, a rectangular region similar to the entire pattern region of the mask M or a rectangular region elongated in the X direction (stationary) so as to optically correspond to the illumination region on the mask M A mask pattern image is formed in the exposure area.

  The mask M is held parallel to the XY plane on the mask stage MS. The mask stage MS incorporates a mechanism for moving the mask M in the X direction, the Y direction, the Z direction, and the rotation direction around the Z axis. The mask stage MS is provided with a movable mirror (not shown), and a mask laser interferometer MIF using this movable mirror moves the position of the mask stage MS (and hence the mask M) in the X direction, the Y direction, and around the Z axis. Measure the position in the rotation direction in real time.

  The wafer W is held parallel to the XY plane on the substrate stage WS via a wafer holder (not shown). A mechanism for moving the wafer W in the X direction, the Y direction, the Z direction, and the rotation direction around the Z axis is incorporated in the substrate stage WS. The substrate stage WS is provided with a movable mirror (not shown), and a substrate laser interferometer WIF using the movable mirror is positioned around the X-axis position, Y-direction position, and Z-axis of the substrate stage WS (and thus the wafer W). Measure the position in the rotation direction in real time.

  The output of the mask laser interferometer MIF and the output of the substrate laser interferometer WIF are supplied to the controller CR. The controller CR controls the position of the mask M in the X direction, the position in the Y direction, and the position in the rotational direction around the Z axis based on the measurement result of the mask laser interferometer MIF. That is, the control unit CR transmits a control signal to a mechanism incorporated in the mask stage MS, and the mechanism moves the mask stage MS based on the control signal, whereby the position of the mask M in the X direction, the Y direction. And the position in the rotation direction around the Z axis are adjusted.

  The controller CR controls the position (focus position) of the wafer W in the Z direction in order to make the surface of the wafer W coincide with the image plane of the projection optical system PL by the autofocus method. Further, the controller CR controls the position of the wafer W in the X direction, the Y direction, and the rotational direction around the Z axis based on the measurement result of the substrate laser interferometer WIF. That is, the control unit CR transmits a control signal to a mechanism incorporated in the substrate stage WS, and the mechanism moves the substrate stage WS based on the control signal, so that the X direction, the Y direction, and the Z direction of the wafer W are changed. Adjust the position of the rotation direction around the shaft.

  In the step-and-repeat method, the pattern image of the mask M is collectively exposed to one unit exposure area among a plurality of unit exposure areas set vertically and horizontally on the wafer W. Thereafter, the controller CR positions the other unit exposure region of the wafer W with respect to the projection optical system PL by step-moving the substrate stage WS along the XY plane. Thus, the operation of collectively exposing the pattern image of the mask M to the unit exposure area of the wafer W is repeated.

  In the step-and-scan method, the control unit CR moves the mask stage MS and the substrate stage WS in the Y direction at a speed ratio corresponding to the projection magnification of the projection optical system PL, and transfers the pattern image of the mask M on the wafer W. One unit exposure area is scanned and exposed. Thereafter, the controller CR positions the other unit exposure region of the wafer W with respect to the projection optical system PL by step-moving the substrate stage WS along the XY plane. Thus, the operation of scanning and exposing the pattern image of the mask M to the unit exposure area of the wafer W is repeated.

  That is, in the step-and-scan method, while performing the position control of the mask M and the wafer W, the mask stage MS and the substrate stage WS are moved along the Y direction which is the short side direction of the rectangular static exposure region. As a result, by moving (scanning) the mask M and the wafer W synchronously, the wafer W has a width equal to the long side of the static exposure region and a length corresponding to the scanning amount (movement amount) of the wafer W. The mask pattern is scanned and exposed to the region having the thickness.

  The exposure apparatus of this embodiment includes an optical path length variable member 1 disposed at a position near the mask M in the optical path of the projection optical system PL. As shown in FIG. 2, the optical path length varying member 1 is disposed in the optical path between the position where the mask M is disposed and the lens L1 disposed closest to the mask in the projection optical system PL. That is, no optical member having power is arranged in the optical path between the position where the mask M is arranged and the optical path length variable member 1.

  The optical path length variable member 1 is disposed on the mask side and has a first declination prism 11 having a wedge-shaped cross section along the XZ plane, and is disposed on the wafer side and has a wedge-shaped cross section along the XZ plane. And a second declination prism 12. Each of the pair of declination prisms 11 and 12 is configured to be movable along the X direction. When the declination prisms 11 and 12 move in the X direction, the first declination prism 11 maintains the posture in which the light incident side surface is orthogonal to the optical axis AX, and the second declination prism 12 is the light emission side surface. Maintains a posture orthogonal to the optical axis AX.

  Further, when the declination prisms 11 and 12 move in the X direction, the slope on the exit side of the first declination prism 11 and the slope on the incident side of the second declination prism 12 maintain a parallel relationship. That is, the optical path length variable member 1 includes a pair of declination prisms 11 and 12 having wedge-shaped cross-sectional shapes that are complementary to each other. In the optical path length variable member 1, the optical path length along the direction parallel to the optical axis AX (Z direction) changes continuously as the declination prisms 11 and 12 move in the X direction. It is constant at any position in a plane (XY plane) perpendicular to the axis AX.

  Hereinafter, the basic principle of the present invention will be described prior to the description of the effects of the present embodiment using the optical path length variable member 1. As shown in FIG. 3, when the pattern surface (corresponding to the pattern surface of the mask M in the present embodiment) 30 is moved from the object surface (not shown) of the projection optical system along the optical axis AX direction, An image plane of the projection optical system (in this embodiment, a transfer surface of the wafer W) is produced by a light beam 31 emitted from the object point on the optical axis AX with a relatively large emission angle and a light beam 32 emitted with a relatively small emission angle. The distance through which the gas in the optical path to the surface on which the surface is disposed (not shown in FIG. 3) changes according to the amount of movement of the pattern surface 30.

  For this reason, as the pattern surface 30 moves in the direction of the optical axis AX, spherical aberration having characteristics as schematically shown in FIG. 4 occurs. In FIG. 4, the horizontal axis indicates the amount of spherical aberration, and the vertical axis indicates the light exit angle from the object point on the optical axis AX of the pattern surface 30 (corresponding to the incident angle of light on the image plane). This notation is the same in the related FIG. 6, FIG. 7, and FIG. In FIG. 4, spherical aberration occurs on the minus side, but spherical aberration occurs on the plus side or the minus side depending on the direction in which the pattern surface 30 moves.

  Next, as shown in FIG. 5, the dimension in the optical axis AX direction of the plane parallel plate 33 having a pair of optical surfaces disposed along the plane orthogonal to the optical axis AX and disposed in the vicinity of the object plane of the projection optical system. That is, the thickness can be changed. In this case, if the thickness of the plane parallel plate 33 is changed from the reference thickness, the light beam 34 emitted from the object point on the optical axis AX of the pattern surface 30 with a relatively large exit angle and a relatively small exit angle. For the light beam 35 emitted at, the distance passing through the parallel plane plate (medium portion) 33 made of an optical material (medium) having a refractive index different from that of the gas in the optical path is the change in the thickness of the parallel plane plate 33. Varies with quantity.

  For this reason, as the thickness of the plane parallel plate 33 changes, spherical aberration as schematically shown in FIG. 6 occurs. FIG. 6 shows a state in which spherical aberration occurs on the minus side, as in FIG. However, spherical aberration occurs on the plus side (or minus side) when the thickness of the plane parallel plate 33 is larger than the reference thickness, and minus side (or when it is smaller than the reference thickness). Spherical aberration occurs on the plus side.

  As described above, when the pattern surface 30 moves in the direction of the optical axis AX, the distance through which the gas in the optical path passes is changed between the light beams 31 and 32 having different emission angles, whereas the thickness of the parallel plane plate 33 is changed. When the distance changes, the distance through which the gas passes through the plane-parallel plate 33 having a different refractive index is changed between the light beams 34 and 35 having different exit angles. Therefore, as shown in FIG. 7, the spherical aberration 41 that occurs as the pattern surface 30 moves in the optical axis AX direction and the spherical aberration 42 that occurs as the thickness of the parallel plane plate 33 changes have properties. It will be different. In FIG. 7, both spherical aberrations 41 and 42 are generated on the minus side so that the difference in the properties of spherical aberration can be easily understood.

  In the present invention, as an example, the pattern surface 30 is moved by a required amount in a required direction along the optical axis AX direction to generate spherical aberration on the plus side (or minus side), and at least one in the projection optical system. By finely adjusting the positions of the two lenses, the amount of spherical aberration corresponding to the light beam having the maximum emission angle is brought close to zero. As a result, the movement of the pattern surface 30 in the direction of the optical axis AX and the fine adjustment of the lens position in the projection optical system cause a spherical aberration having the property shown by reference numeral 51 in FIG.

  Further, by changing the thickness of the plane-parallel plate 33 by a required amount, spherical aberration is generated on the minus side (or plus side), and the maximum emission is achieved by finely adjusting the position of at least one lens in the projection optical system. The amount of spherical aberration corresponding to the angular ray is brought close to zero. As a result, due to the change in the thickness of the plane-parallel plate 33 and the fine adjustment of the lens position in the projection optical system, a spherical aberration having the property shown by reference numeral 52 in FIG. 8 occurs.

  Thus, in the present invention, the movement of the pattern surface 30 in the direction of the optical axis AX, the change in the thickness of the plane-parallel plate 33, and the fine adjustment of the lens position in the projection optical system are linked to each other, so Using the difference between 51 and 52, that is, spherical aberration 53 having a complicated property indicated by a broken line denoted by reference numeral 53 in FIG. 8, not only low-order spherical aberration but also high-order spherical aberration of the projection optical system is improved. It can be corrected (adjusted).

  In the description with reference to FIG. 8, the difference between the spherical aberration 41 that occurs as the pattern surface 30 moves in the optical axis AX direction and the spherical aberration 42 that occurs as the thickness of the parallel plane plate 33 changes. As a usage example, the spherical aberration amount corresponding to the light beam having the maximum exit angle is brought close to 0 by fine adjustment of the lens position in the projection optical system. However, in practice, the lens position in the projection optical system is finely adjusted as necessary so that the amount of spherical aberration corresponding to the light beam at each exit angle is suppressed to a desired range.

  In the description with reference to FIGS. 3 to 8, the movement of the pattern surface 30 in the optical axis AX direction from the object plane of the projection optical system and the parallel plane plate 33 arranged in the vicinity of the object plane of the projection optical system. The change in thickness is linked. However, the present invention is not limited to this, and the movement in the optical axis direction of the image forming surface (corresponding to the transfer surface of the wafer W in the present embodiment) from the image surface of the projection optical system and the vicinity of the image surface of the projection optical system The same effect can be obtained by interlocking with the change in the thickness of the plane parallel plate disposed on the plate.

  In the exposure apparatus of the present embodiment, the control unit CR moves the pair of declination prisms 11 and 12 in the optical path length variable member 1 by a required amount in the required direction along the X direction, thereby serving as the medium unit. The optical path length along the Z direction (direction parallel to the optical axis AX) in the declination prisms 11 and 12 is changed. Further, the controller CR moves the mask stage MS by a required amount in a required direction along the optical axis AX direction in conjunction with the change of the optical path length in the optical path length variable member 1, thereby making the pattern surface of the mask M Is moved from the object plane of the projection optical system PL in the required direction along the optical axis AX direction by a required amount.

  Further, the control unit CR finely adjusts the position of at least one lens in the projection optical system PL in conjunction with the change in the optical path length in the optical path length variable member 1 and the movement of the mask stage MS as necessary. Note that the control unit CR changes the optical path length and moves the mask stage MS based on instruction data supplied from input means (not shown), measurement data supplied from an aberration measurement unit (not shown), and the like. , And necessary operations relating to fine adjustment of the lens position.

  Thus, in the exposure apparatus of the present embodiment, the spherical aberration that occurs with the movement of the mask stage MS in the optical axis AX direction and the change in the optical path length of the declination prisms 11 and 12 in the optical path length variable member 1 occur. The spherical aberration of the projection optical system PL can be corrected (adjusted) satisfactorily using the difference from the spherical aberration, that is, the difference between two spherical aberrations having different properties. As a result, the fine pattern of the mask M can be accurately transferred onto the wafer W using the projection optical system PL in which the spherical aberration is well corrected.

  In the above description, in the optical path length variable member 1, the pair of declination prisms 11 and 12 having a wedge-shaped cross-sectional shape complementary to each other are along the X direction (generally, the direction orthogonal to the optical axis AX). It is configured to be movable. However, the present invention is not limited to this, and at least one of the pair of declination prisms 11 and 12 is configured to be movable along the X direction, or is inclined (the surface or declination on the exit side of the declination prism 11). It may be configured to be movable in a direction (generally, a direction intersecting with the optical axis AX) along the surface on the incident side of the prism 12. A configuration in which a pair of wedge-shaped optical members are moved along the oblique side of the wedge is disclosed in, for example, International Patent Publication No. 20000/012611 pamphlet.

  Further, in the above description, the optical path length variable member 1 is constituted by the pair of declination prisms 11 and 12 that can move in the X direction. However, the present invention is not limited to this, and various configurations are possible for the specific configuration of the optical path length variable member. In general, the optical path length variable member is disposed at a position in the vicinity of the mask in the optical path of the projection optical system (or a position in the vicinity of the photosensitive substrate as will be described later) and from a medium having a refractive index different from that of the gas in the optical path. And has a function of changing the optical path length along a direction parallel to the optical axis of the medium portion.

  Specifically, for example, as shown in FIG. 9, a plurality of (two in the example in FIG. 9) parallel plane plates having variable thicknesses that are interchangeable with respect to the optical path of the projection optical system PL. A configuration having 61 and 62 is also possible. In the modification of FIG. 9, the medium plane (that is, the plane parallel plate) in the optical path length variable member is obtained by replacing the plane parallel plate 61 disposed in the optical path of the projection optical system PL with a plane parallel plate 62 having a different thickness. ) In the Z direction.

  For example, as shown in FIG. 10, an optical path length variable member having a liquid layer filled in a parallel flat plate-like space 67 having a variable dimension in the optical axis AX direction may be used. In the modification of FIG. 10, a pair of parallel flat plates 64 and 65 and a bellows-like side member 66 form a parallel flat plate-like space 67 whose dimensions in the Z direction can be changed. In this modification, the medium portion of the optical path length variable member is changed by changing the amount of liquid (generally fluid) filling the internal space 67 while maintaining the parallel plane plates 64 and 65 in a parallel relationship. That is, the optical path length along the Z direction of the liquid layer is changed.

  In the above description, the optical path length variable member 1 is arranged in the optical path between the position where the mask M is arranged and the lens L1 arranged on the most mask side in the projection optical system PL. However, the present invention is not limited to this, and various forms are possible for the arrangement of the optical path length variable member. For example, in the configuration of the above-described embodiment, the optical path length variable member can be disposed at a position nearer to the mask M on the wafer side than the lens L1 disposed on the most mask side.

  Further, unlike the above-described embodiment, an embodiment in which the optical path length variable member 1 is arranged at a position near the wafer W as shown in FIG. 11 is also possible. In this case, the optical path length variable member 1 is disposed in the optical path between the position where the wafer W is disposed and the lens disposed closest to the wafer in the projection optical system PL, or disposed closest to the wafer. It is arranged at a position near the wafer W on the mask side of the formed lens.

  In the embodiment of FIG. 11, the transfer surface of the wafer W is moved by a required amount in the required direction along the optical axis AX in conjunction with the change of the optical path length in the optical path length variable member 1. Is moved from the image plane of the projection optical system PL in a required direction along the optical axis AX direction by a required amount. Further, if necessary, the position of at least one lens in the projection optical system PL is finely adjusted in conjunction with the change in the optical path length in the optical path length variable member 1 and the movement of the substrate stage WS. Thus, also in the embodiment of FIG. 11, the spherical aberration of the projection optical system PL can be corrected (adjusted) satisfactorily.

  In the above-described embodiment, a variable pattern forming apparatus (fixed pattern type mask) that forms a predetermined pattern based on predetermined electronic data can be used instead of the fixed pattern type mask provided with a fixed pattern. As the variable pattern forming apparatus, for example, a DMD (digital micromirror device) including a plurality of reflecting elements driven based on predetermined electronic data can be used. An exposure apparatus using DMD is disclosed in, for example, Japanese Patent Application Laid-Open No. 2004-304135, International Patent Publication No. 2006/080285 pamphlet and US Patent Publication No. 2007/0296936 corresponding thereto. In addition to a non-light-emitting reflective spatial light modulator such as DMD, a transmissive spatial light modulator may be used, or a self-luminous image display element may be used. Note that a variable pattern forming apparatus may be used even when the pattern surface is placed horizontally. Here, the teachings of US Patent Publication No. 2007/0296936 are incorporated by reference.

  The exposure apparatus of the above-described embodiment is manufactured by assembling various subsystems including the respective constituent elements recited in the claims of the present application so as to maintain predetermined mechanical accuracy, electrical accuracy, and optical accuracy. Is done. In order to ensure these various accuracies, before and after assembly, various optical systems are adjusted to achieve optical accuracy, various mechanical systems are adjusted to achieve mechanical accuracy, and various electrical systems are Adjustments are made to achieve electrical accuracy. The assembly process from the various subsystems to the exposure apparatus includes mechanical connection, electrical circuit wiring connection, pneumatic circuit piping connection and the like between the various subsystems. Needless to say, there is an assembly process for each subsystem before the assembly process from the various subsystems to the exposure apparatus. When the assembly process of the various subsystems to the exposure apparatus is completed, comprehensive adjustment is performed to ensure various accuracies as the entire exposure apparatus. The exposure apparatus may be manufactured in a clean room where the temperature, cleanliness, etc. are controlled.

  Next, a device manufacturing method using the exposure apparatus according to the above-described embodiment will be described. FIG. 12 is a flowchart showing a manufacturing process of a semiconductor device. As shown in FIG. 12, in the semiconductor device manufacturing process, a metal film is vapor-deposited on a wafer W to be a substrate of the semiconductor device (step S40), and a photoresist, which is a photosensitive material, is applied on the vapor-deposited metal film. (Step S42). Subsequently, using the exposure apparatus of the above-described embodiment, the pattern formed on the mask (reticle) M is transferred to each shot area on the wafer W (step S44: exposure process), and the transfer of the wafer W after the transfer is completed. Development, that is, development of the photoresist to which the pattern has been transferred is performed (step S46: development process). Thereafter, using the resist pattern generated on the surface of the wafer W in step S46 as a mask, processing such as etching is performed on the surface of the wafer W (step S48: processing step).

  Here, the resist pattern is a photoresist layer in which unevenness having a shape corresponding to the pattern transferred by the exposure apparatus of the above-described embodiment is generated, and the recess penetrates the photoresist layer. is there. In step S48, the surface of the wafer W is processed through this resist pattern. The processing performed in step S48 includes, for example, at least one of etching of the surface of the wafer W or film formation of a metal film or the like. In step S44, the exposure apparatus of the above-described embodiment performs pattern transfer using the wafer W coated with the photoresist as the photosensitive substrate, that is, the plate P.

  FIG. 13 is a flowchart showing a manufacturing process of a liquid crystal device such as a liquid crystal display element. As shown in FIG. 13, in the liquid crystal device manufacturing process, a pattern formation process (step S50), a color filter formation process (step S52), a cell assembly process (step S54), and a module assembly process (step S56) are sequentially performed.

  In the pattern forming process of step S50, a predetermined pattern such as a circuit pattern and an electrode pattern is formed on the glass substrate coated with a photoresist as the plate P using the exposure apparatus of the above-described embodiment. In this pattern formation process, an exposure process for transferring the pattern to the photoresist layer using the exposure apparatus of the above-described embodiment and development of the plate P to which the pattern is transferred, that is, development of the photoresist layer on the glass substrate are performed. And a developing step for generating a photoresist layer having a shape corresponding to the pattern, and a processing step for processing the surface of the glass substrate through the developed photoresist layer.

  In the color filter forming step of step S52, a large number of sets of three dots corresponding to R (Red), G (Green), and B (Blue) are arranged in a matrix or three R, G, and B A color filter is formed by arranging a plurality of stripe filter sets in the horizontal scanning direction.

  In the cell assembly process in step S54, a liquid crystal panel (liquid crystal cell) is assembled using the glass substrate on which the predetermined pattern is formed in step S50 and the color filter formed in step S52. Specifically, for example, a liquid crystal panel is formed by injecting liquid crystal between a glass substrate and a color filter. In the module assembling process in step S56, various components such as an electric circuit and a backlight for performing the display operation of the liquid crystal panel are attached to the liquid crystal panel assembled in step S54.

  In addition, the present invention is not limited to application to an exposure apparatus for manufacturing a semiconductor device, for example, an exposure apparatus for a display device such as a liquid crystal display element formed on a square glass plate or a plasma display, It can also be widely applied to an exposure apparatus for manufacturing various devices such as an image sensor (CCD or the like), a micromachine, a thin film magnetic head, and a DNA chip. Furthermore, the present invention can also be applied to an exposure process (exposure apparatus) when manufacturing a mask (photomask, reticle, etc.) on which mask patterns of various devices are formed using a photolithography process.

  In the above-described embodiment, a so-called immersion method is applied in which the optical path between the projection optical system and the photosensitive substrate is filled with a medium (typically liquid) having a refractive index larger than 1.1. You may do it. In this case, as a method for filling the liquid in the optical path between the projection optical system and the photosensitive substrate, a method for locally filling the liquid as disclosed in International Publication No. WO 99/49504, A method of moving a stage holding a substrate to be exposed as disclosed in Japanese Patent Application Laid-Open No. 6-124873 in a liquid bath, or a predetermined depth on a stage as disclosed in Japanese Patent Application Laid-Open No. 10-303114. A technique of forming a liquid tank and holding the substrate in the liquid tank can be employed. Here, the teachings of International Publication No. WO99 / 49504, JP-A-6-124873 and JP-A-10-303114 are incorporated by reference.

  In the above-described embodiment, a so-called polarization illumination method disclosed in US Publication Nos. 2006/0170901 and 2007/0146676 can be applied. Here, the teachings of US Patent Publication No. 2006/0170901 and US Patent Publication No. 2007/0146676 are incorporated by reference.

DESCRIPTION OF SYMBOLS 1 Optical path length variable member 11, 12 Deflection prism LS Light source IL Illumination optical system M Mask MS Mask stage PL Projection optical system W Wafer WS Wafer stage CR Control part

Claims (13)

In an exposure apparatus that projects and exposes a mask pattern onto a photosensitive substrate via a projection optical system,
A mask stage that holds the mask movably in the optical axis direction of the projection optical system;
In the optical path of the projection optical system, there is a medium part made of a medium having a refractive index different from that of the gas in the optical path disposed in the vicinity of the mask, and in a direction parallel to the optical axis of the medium part An optical path length variable member that changes the optical path length along the path,
In order to correct higher-order spherical aberration of the projection optical system, a control unit is provided for interlocking the change of the optical path length of the medium portion and the movement of the mask stage in the optical axis direction in the optical path length variable member. An exposure apparatus characterized by comprising: 2. The exposure apparatus according to claim 1, wherein an optical path length along the direction parallel to the optical axis of the medium portion is constant at any position in a plane perpendicular to the optical axis. 3. The exposure apparatus according to claim 1, wherein an optical member having power is not disposed in an optical path between the position where the mask is disposed and the optical path length variable member. In an exposure apparatus that projects and exposes a mask pattern onto a photosensitive substrate via a projection optical system,
A substrate stage for holding the photosensitive substrate movably in the optical axis direction;
A medium portion made of a medium having a refractive index different from that of the gas in the optical path, disposed in a position near the photosensitive substrate in the optical path of the projection optical system, and parallel to the optical axis of the medium portion; An optical path length variable member that changes the optical path length along the direction;
In order to correct higher-order spherical aberration of the projection optical system, a control unit is provided that interlocks the change in the optical path length of the medium portion with the movement of the substrate stage in the optical axis direction in the optical path length variable member. An exposure apparatus characterized by comprising: 5. The exposure apparatus according to claim 4, wherein an optical path length along the direction parallel to the optical axis of the medium portion is constant at any position in a plane perpendicular to the optical axis. 6. The exposure apparatus according to claim 4, wherein an optical member having power is not disposed in an optical path between the position where the photosensitive substrate is disposed and the optical path length variable member. The variable optical path length member has a pair of declination prisms having a wedge-shaped cross section complementary to each other, and at least one of the pair of declination prisms is movable in a direction intersecting the optical axis. The exposure apparatus according to claim 1, wherein the exposure apparatus is configured as follows. The exposure according to claim 1, wherein the optical path length variable member includes a plurality of parallel flat plates having different thicknesses that can be exchanged with respect to the optical path of the projection optical system. apparatus. The said optical path length variable member has the liquid layer with which the dimension of the said optical axis direction was filled with the space of the parallel plane plate shape comprised variably, The said any one of Claim 1 thru | or 6 characterized by the above-mentioned. Exposure equipment. In an exposure method for projecting and exposing a predetermined pattern onto a photosensitive substrate via a projection optical system,
In order to correct higher-order spherical aberration of the projection optical system, the pattern is arranged in the vicinity of the pattern in conjunction with the movement of the projection optical system in the optical axis direction, and is different from the gas in the optical path. An exposure method characterized by changing an optical path length along a direction parallel to the optical axis of a medium portion made of a refractive index medium. In an exposure method for projecting and exposing a predetermined pattern onto a photosensitive substrate via a projection optical system,
In order to correct higher-order spherical aberration of the projection optical system, the photosensitive substrate is disposed at a position in the vicinity of the photosensitive substrate in conjunction with the movement of the projection optical system in the optical axis direction. An exposure method comprising: changing an optical path length along a direction parallel to the optical axis of a medium portion made of a medium having a refractive index different from that of gas. 12. The exposure according to claim 10, wherein an optical path length along the direction parallel to the optical axis of the medium portion is constant at any position in a plane perpendicular to the optical axis. Method. An exposure step of exposing the photosensitive substrate with a pattern of the mask using the exposure apparatus according to claim 1;
Developing the photosensitive substrate to which the pattern has been transferred, and forming a mask layer having a shape corresponding to the pattern on the surface of the photosensitive substrate;
And a processing step of processing the surface of the photosensitive substrate through the mask layer.

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