Stage apparatus, exposure apparatus and device manufacturing method

An exposure apparatus comprises a stage main body having a mounting surface, and a correcting mechanism that corrects a shape of the mounting surface.

BACKGROUND

1. Field of the Invention

The present invention relates to a stage apparatus, an exposure apparatus, and device manufacturing method.

2. Description of Related Art

Exposure apparatuses used in photolithographic processes expose a substrate by illuminating a mask with exposure light and exposing the substrate with the exposure light that passes through the mask. Such an exposure apparatus comprises a mask stage, which holds and moves the mask, and a substrate stage, which holds and moves the substrate, as disclosed in, for example, U.S. Patent Application Publication No. 2005/0248744. A technique is known in the art wherein the mask stage holds the mask by, for example, chucking the mask to a mounting surface of the mask stage.

Notwithstanding the above, holding the mask on the mounting surface via, for example, chucking risks deforming the mask, which in turn warps the shape of the mask. Warpage in the shape of the mask will lead to distortion in the pattern of the mask. If an exposure is formed in the state wherein the distortion of the pattern is left as is, then exposure failures, such as a reduction in the overlay accuracy of the pattern on the substrate or a defect in the pattern formed on the substrate, might occur. These potential problems could also result in the production of defective devices. There is a significant possibility that exposure failures and defective devices will occur not only because of the warpage of the mask but also because of warpage in the shape of an object mounted on the mounting surface, such as the substrate on the substrate stage.

A purpose of an aspect of the present invention is to provide a stage apparatus that can correct warpage in the shape of a surface that contacts a mounting surface and an exposure apparatus that can prevent exposure failures from occurring.

SUMMARY

A stage apparatus according to an aspect of the present invention comprises: a stage main body, which is moveably provided and has a mounting surface; and a correcting mechanism, which corrects a shape of the mounting surface.

According to the abovementioned configuration, the correcting mechanism can correct the shape of the mounting surface, and therefore the shape of the surface that contacts the mounting surface can be deformed to a desired shape by the mounting surface, whose shape has been corrected. Thereby, the warpage in the shape of the surface that contacts the mounting surface can be corrected.

In addition, an exposure apparatus according to an aspect of the present invention comprises the abovementioned stage apparatus.

The abovementioned configuration comprises a stage apparatus capable of correcting warpage in the shape of the mounting surface, which makes it possible to prevent exposure failures from occurring owing to warpage of the shape of the surface that contacts the mounting surface.

According to some aspects of the present invention, it is possible to correct warpage in the shape of a surface that contacts a mounting surface and to prevent exposure failures from occurring.

DESCRIPTION OF EMBODIMENTS

The following text explains the embodiments of the present invention referencing the drawings, but the present invention is not limited thereto. The explanation below defines an XYZ orthogonal coordinate system, and the positional relationships among members are explained referencing this system. Prescribed directions within the horizontal plane are the X axial directions, directions orthogonal to the X axial directions in the horizontal plane are the Y axial directions, and directions orthogonal to the X axial directions and the Y axial directions (i.e., the vertical directions) are the Z axial directions. In addition, the rotational (i.e., inclinational) directions around the X, Y, and Z axes are the θX, θY, and θZ directions, respectively.

FIG. 1is a schematic block diagram that shows one example of an exposure apparatus EX according to the first embodiment. InFIG. 1, the exposure apparatus EX comprises a movable mask stage1that holds a mask M; a movable substrate stage2that holds a substrate P; an illumination system IL, which illuminates the mask M supported by the mask stage1with exposure light EL; a projection optical system PL, which projects an image of a pattern of the mask M illuminated by the exposure light EL onto the substrate P held by the substrate stage2; and a control apparatus3, which controls the operation of the entire exposure apparatus EX. The control apparatus3includes, for example, a computer system. In addition, the exposure apparatus EX comprises a chamber apparatus5in which an internal space4, wherein the substrate P is processed, is formed. The chamber apparatus5is capable of adjusting the environment (including the temperature, humidity, and cleanliness level) of the internal space4.

The substrate P is a substrate for fabricating a device and may be a substrate wherein a photosensitive film is formed on a base material such as a semiconductor wafer, for example, a silicon wafer. The photosensitive film is made of a photosensitive material (e.g., photoresist). In addition, various films may be formed on the substrate P; for example, a protective (topcoat) film may be formed on the photosensitive film.

The mask M may be, for example, a reticle wherein a device pattern projected onto the substrate P is formed. In the present embodiment, the mask M is a transmissive mask wherein a light shielding film made of chrome and the like is used to form a prescribed pattern on a transparent plate, such as a glass plate. This transmissive mask is not limited to a binary mask wherein a pattern is formed with a light shielding film, but may also include, for example, a halftone type or a spatial frequency modulation type phase shift mask. In addition, although a transmissive mask is used as the mask M in the present embodiment, a reflective mask may also be used.

The exposure apparatus EX of the present embodiment is a scanning type exposure apparatus (i.e., a so-called scanning stepper) that exposes the substrate P with the exposure light EL through the mask M while synchronously moving the mask M and the substrate P in prescribed scanning directions. In the present embodiment, the scanning directions (i.e., the synchronous movement directions) of both the substrate P and the mask M are the Y axial directions. The exposure apparatus EX illuminates the mask M with the exposure light EL and radiates the exposure light EL that passes through the mask M to the substrate P through the projection optical system PL while both moving the substrate P in one of the Y axial directions with respect to a projection region PR of the projection optical system PL and moving the mask M in the other Y axial direction with respect to an illumination region IR of the illumination system IL synchronized to the movement of the substrate P. The illumination region IR of the illumination system IL includes an irradiation position of the exposure light EL that emerges from the illumination system IL, and the projection region PR of the projection optical system PL includes an irradiation position of the exposure light EL that emerges from the projection optical system PL.

The exposure apparatus EX comprises a body8that comprises: a first column (frame)6, which is provided on a floor surface FL inside, for example, a clean room; and a second column (frame)7, which is provided on the first column6. The first column6comprises: a plurality of first support posts9; and a first plate11, which is supported by the first support posts9via vibration isolating apparatuses10. The second column7comprises: a plurality of second support posts12, which are provided on the first plate11, and a second plate13, which is supported by the second support posts12.

The illumination system IL illuminates the prescribed illumination region IR with the exposure light EL, which has a uniform luminous flux intensity distribution. The mask M is capable of moving to the illumination region IR of the illumination system IL (i.e., the irradiation position of the exposure light EL). The illumination system IL illuminates at least part of the mask M disposed in the illumination region IR with the exposure light EL, which has a uniform luminous flux intensity distribution. Examples of light that can be used as the exposure light EL that emerges from the illumination system IL include: deep ultraviolet (DUV) light such as a bright line (g-line, h-line, or i-line) light emitted from, for example, a mercury lamp and KrF excimer laser light (with a wavelength of 248 nm); and vacuum ultraviolet (VUV) light such as ArF excimer laser light (with a wavelength of 193 nm) and F2laser light (with a wavelength of 157 nm). In the present embodiment, ArF excimer laser light, which is ultraviolet light (i.e., vacuum ultraviolet light), is used as the exposure light EL.

The mask stage1comprises a mask holding part14, which holds the mask M when the mask M is irradiated with the exposure light EL. The mask holding part14is capable of chucking and releasing the mask M. In the present embodiment, the mask holding part14holds the mask M such that a lower surface Mb (i.e., a patterned surface) of the mask M is substantially parallel to the XY plane. The mask stage1is supported noncontactually by an upper surface13G (i.e., a guide surface) of the second plate13via a gas bearing. In the present embodiment, the upper surface13G of the second plate13is substantially parallel to the XY plane. The mask stage1holds the mask M and is capable of moving, by the operation of a mask stage drive apparatus15that comprises actuators such as linear motors, along the upper surface13G of the second plate13, which includes the irradiation position of the exposure light EL that emerges from the illumination system IL (i.e., the illumination region IR of the illumination system IL). In the present embodiment, in the state wherein the mask M is held by the mask holding part14, the mask stage1is capable of moving on the second plate13in three directions: the X axial, Y axial, and θZ directions. The mask stage1has a first opening16through which the exposure light EL passes when, for example, the substrate P is exposed or when a measurement is performed using the exposure light EL. The second plate member13has a second opening17wherethrough the exposure light EL passes. The exposure light EL that emerges from the illumination system IL and illuminates the mask M passes through the first opening16and the second opening17and then enters the projection optical system PL.

In addition, a countermass18is provided on the second plate13that, in accordance with the movement of the mask stage1in one of the Y axial directions (e.g., the +Y direction), moves in the direction opposite that of the mask stage1(e.g., the −Y direction). The countermass18is supported noncontactually by the upper surface13G of the second plate13via a self-weight cancelling mechanism, which comprises air pads. In the present embodiment, the countermass18is provided around the mask stage1.

Laser interferometers19A of an interferometer system19measure the position of the mask stage1(i.e., the mask M). The laser interferometers19A radiate measurement light beams LB to reflecting surfaces1R of the mask stage1. The laser interferometers19A use the measurement light beams LB, which are radiated to the reflecting surfaces1R of the mask stage1, to measure the position of the mask stage1in the X axial, Y axial, and θZ directions. The control apparatus3operates the mask stage drive apparatus15based on the measurement results of the interferometer system19(i.e., the laser interferometers19A) to control the position of the mask M, which is held by the mask stage1.

The projection optical system PL radiates the exposure light EL to the prescribed projection region PR. The substrate P is capable of moving to the projection region PR of the projection optical system PL (i.e., the irradiation position of the exposure light EL). The projection optical system PL projects with a prescribed projection magnification an image of the pattern of the mask M to at least part of the substrate P, which is disposed in the projection region PR. A lens barrel20holds the plurality of optical elements of the projection optical system PL. The lens barrel20comprises a flange21. The flange21is supported by the first plate11. The projection optical system PL of the present embodiment is a reduction system that has a projection magnification of, for example, ¼, ⅕, or ⅛. Furthermore, the projection optical system PL may alternatively be a unity magnification system or an enlargement system. In the present embodiment, an optical axis AX of the projection optical system PL is parallel to the Z axis. In addition, the projection optical system PL may be a dioptric system that does not include catoptric elements, a catoptric system that does not include dioptric elements, or a catadioptric system that includes both catoptric and dioptric elements. In addition, the projection optical system PL may form either an inverted or an erect image.

The substrate stage2comprises a substrate holding part22, which holds the substrate P that is irradiated by the exposure light EL. The substrate holding part22is capable of chucking and releasing the substrate P. In the present embodiment, the substrate holding part22holds the substrate P such that an exposure surface Pa (i.e., an upper surface) of the substrate P is substantially parallel to the XY plane. The substrate stage2is supported noncontactually by an upper surface23G (i.e., a guide surface) of a third plate23via a gas bearing. In the present embodiment, the upper surface23G of the third plate23is substantially parallel to the XY plane. The third plate23is supported by the floor surface FL via vibration isolating apparatuses24. The substrate stage2holds the substrate P and is capable of moving, by the operation of a substrate stage drive apparatus25that comprises actuators such as linear motors, along the upper surface23G of the third plate23, which includes the irradiation position of the exposure light EL that emerges from the projection optical system PL (i.e., the projection region PR of the projection optical system PL). In the present embodiment, in the state wherein the substrate P is held by the substrate holding part22, the substrate stage2is capable of moving on the third plate23in six directions: the X, Y, and Z axial directions, and the θX, θY, and θZ directions.

Laser interferometers19B of the interferometer system19measure the position of the substrate stage2(i.e., the substrate P). The laser interferometers19B radiate the measurement light beams LB to reflecting surfaces2R of the substrate stage2. The laser interferometers19B use the measurement light beams LB, which are radiated to the reflecting surfaces2R of the substrate stage2, to measure the position of the substrate stage2in the X axial, Y axial, and θZ directions. In addition, a focus and level detection system (not shown) detects the surface position (i.e., the position in the Z axial, θX, and θY directions) of the exposure surface Pa of the substrate P held by the substrate stage2. The control apparatus3controls the position of the substrate P, which is held by the substrate stage2, by operating the substrate stage drive apparatus25based on the measurement results of the interferometer system19(i.e., the laser interferometers19B) and the detection results of the focus and level detection system.

The mask stage1will now be explained, referencingFIG. 2,FIG. 3, andFIG. 4.FIG. 2is an oblique view of the vicinity of the mask stage1, the countermass18, and the second plate13according to the present embodiment;FIG. 3is an oblique view that shows the configuration of part of the mask stage1; andFIG. 4is a cross sectional auxiliary view taken along the A-A line inFIG. 3.

InFIGS. 2,3, and4, the mask stage1comprises a mask stage main body27, which is provided with the mask holding part14.

As shown inFIG. 2, the mask stage main body27comprises a first member28, which is substantially rectangular within the XY plane, and a second member29, which is long in the Y axial directions and is connected to the +X side end of the first member28. The mask holding part14is provided to the first member28. The first opening16is formed at substantially the center of the first member28. The mask holding part14is disposed at least partly around the first opening16.

The +Y side side surface of the first member28has one of the reflecting surfaces1R, which is irradiated with the measurement light beam LB of one of the laser interferometers19A. The reflecting surface1R of the first member28is substantially perpendicular to the Y axis. A transmissive area18Y, wherethrough the measurement light beam LB of the corresponding laser interferometer19A can be transmitted, is disposed on the +Y side side surface of the countermass18. This laser interferometer19A is capable of radiating its measurement light beam LB to the reflecting surface1R of the first member28through the transmissive area18Y.

The +X side side surface of the first member29has one of the reflecting surfaces1R, which is irradiated with the measurement light beam LB of one of the laser interferometers19A. The reflecting surface1R of the second member29is substantially perpendicular to the X axis. A transmissive area18X, wherethrough the measurement light beam LB of the corresponding laser interferometer19A can be transmitted, is disposed on the +X side side surface of the countermass18. This laser interferometer19A is capable of radiating its measurement light beam LB to the reflecting surface1R of the second member29through the transmissive area18X.

In the present embodiment, a protruding part13A is provided at substantially the center of the second plate13. The guide surface13G of the second plate13includes the upper surface of the protruding part13A. Vacuum preloaded air pads57are provided to the surface of the first member28that opposes the guide surface13G. The air pads57blow air toward the guide surface13G and thereby the first member28is levitationally (noncontactually) supported by the guide surface13G with a clearance of, for example, several microns. In addition, the air pads57are configured such that they can maintain the abovementioned clearance by blowing air between the first member28and the guide surface13G. The mask stage main body27is configured such that it is supported noncontactually by the upper surface13G of the protruding part13A via the air pads57. The second opening17is provided at substantially the center of the protruding part13A of the second plate13.

As shown inFIG. 3andFIG. 4, the first member28has a recessed part40. The recessed part40is disposed in a rectangular area in the XY plane at substantially the center part of the first member28. The mask holding part14is disposed on the inner side of the recessed part40. The first opening16, wherethrough the exposure light EL passes, is disposed on the inner side of the recessed part40. The first opening16is disposed in a rectangular area in the XY plane at substantially the center part of the recessed part40.

The mask holding part14comprises: pedestals43, which are disposed at the perimeter of the first opening16; and chucking pads44, which are provided to the pedestals43. The chucking pads44are provided to upper surfaces43T of the pedestals43. The pedestals43(namely, an +X pedestal43A and a −X pedestal43B) and the chucking pads44are disposed along two opposing sides of the four sides of the first opening16and are oriented such that their longitudinal directions are in the Y axial directions. Each of the chucking pads44has a holding surface45that holds at least part of the lower surface Mb of the mask M.

Each of the holding surfaces45includes at least part of the upper surface43T of the corresponding pedestal43. In the present embodiment, the holding surfaces45are substantially parallel to the XY plane. In addition, in the present embodiment, the surface inside the recessed part40that includes the holding surfaces45is a mounting surface45a, whereon the mask M is mounted. Each of the chucking pads44comprises: a groove46, which is formed in part of the upper surface43T of the corresponding pedestal43; and suction ports47, which are formed on the inner sides of the groove46. Each of the holding surfaces45includes a portion of the upper surface43T of the corresponding pedestal43wherein the groove46is not formed. The suction ports47are connected to a suction apparatus, which comprises a vacuum system, via passageways (not shown).

Each of the chucking pads44holds the mask M such that at least part of the lower surface Mb of the mask M is chucked. By operating the suction apparatus, which is connected to the suction ports47, in the state wherein the chucking pads44and the holding surfaces45have been brought into contact with part of the lower surface Mb of the mask M, the suction ports47suction the gas from the space enclosed by the lower surface Mb of the mask M and the inner surfaces of the grooves46, thereby negatively pressurizing the space. Thereby, the lower surface Mb of the mask M is chucked to the holding surfaces45. The mask stage1is capable of moving while the holding surfaces45hold the mask M. In addition, the mask M can be removed from the mask holding part14by stopping the suction operation wherein the suction ports47are used.

The mask M has a patterned area, wherein a pattern is formed, in part of the lower surface Mb, and the chucking pads44, which include the holding surfaces45, hold that area of the lower surface Mb of the mask M that lies outside of the patterned area. The mask holding part14holds the mask M such that the patterned area of the mask M is disposed in the first opening16. The mask holding part14holds the mask M such that the lower surface Mb of the mask M is substantially parallel to the XY plane. In addition, an upper surface Ma of the mask M, which is held by the mask holding part14, is substantially parallel to the XY plane.

The mask stage drive apparatus15is capable of moving the mask stage1. The mask stage drive apparatus15comprises a first drive apparatus30, which is capable of moving the mask stage1in the Y axial and θZ directions, and a second drive apparatus31, which is capable of moving the mask stage1in the X axial directions. In the present embodiment, the first drive apparatus30comprises a pair of linear motors32,33. The second drive apparatus31comprises a voice coil motor36.

The first drive apparatus30comprises a pair of guide members34,35, each of which is long in the Y axial directions (i.e., the movement directions). The guide members34,35are disposed on the inner side of the countermass18. The guide member34is disposed on the +X side of the first member28, and the guide member35is disposed on the −X side of the first member28. Accordingly, the guide members34, are provided at positions spaced apart in the X axial directions. The +Y and −Y side ends of the guide members34,35are fixed to the inner surface of the countermass18via prescribed fixed members. The guide members34,35are supported such that they are capable of moving the mask stage main body27in the Y axial directions.

The guide members34,35each have coil units51that function as the stators of the linear motors32,33. As shown inFIG. 4, for each of the guide members34,35two coil units51are disposed such that they are arrayed in the Z axial directions. Each of the coil units51comprises a coil part52and a coil holding member53, which holds the coil part52. The coil holding members53are disposed along the guide members34,35and are configured such that they are long in the Y axial directions. Each of the coil parts52comprises two coils52a,52b, which are disposed in the Z axial directions. The coils52a,52bare arrayed such that their U phases, V phases, and W phases repeat along the Y axial directions. Each coil52aand its corresponding coil52bare provided at positions such that they overlap in a plan view, and electric currents can be flowed thereto independently. Accordingly, the electric currents that flow to each of the coils52aand its corresponding coil52bcan be flowed in the same direction or in different directions.

In the present embodiment, the first member28of the mask stage main body27comprises magnet units55that function as the sliders of the linear motors32,33. The magnet units55are disposed at a +X side end surface28aand a −X side end surface28bof the first member28; two units are disposed on each side and arrayed in the Z axial directions such that they correspond to the two coil units51of each of the guide members34,35. The magnet units55are fixed to the +X side end surface28aand the −X side end surface28bof the first member28via fixed members56. The end surfaces28a,28bare first positions at which the driving forces of the mask stage drive apparatus (mask stage drive mechanism, correcting mechanism)15is applied.

Each of the magnet units55comprises a magnet55a, which is disposed on the +Z side, a magnet55b, which is disposed on the −Z side, and a magnet holding member55c, which holds the magnets55a,55b. Each of the magnets55a, opposes the coil52aof the corresponding coil unit51, and each of the magnets55bopposes the coil52bof the corresponding coil unit.

In the present embodiment, the slider provided to the +X side end surface28aof the first member28and the stator provided to the guide member34together form the moving magnet type linear motor32, which is capable of moving the mask stage main body27in the Y axial directions. Similarly, the slider provided to the −X side end surface28bof the first member28and the stator provided to the guide member35together form the moving magnet type linear motor33, which is capable of moving the mask stage main body27in the Y axial directions.

The control apparatus3, by equalizing the thrusts generated by the pair of linear motors32,33, can control the position of the mask stage1(i.e., the mask stage main body27) in the Y axial directions by moving the mask stage1in those directions. In addition, the control apparatus3, by making the thrusts generated by the pair of linear motors32,33different from one another, can control the position of the mask stage1(i.e., the mask stage main body27) in the θZ directions by moving (i.e., rotating) the mask stage1in those directions. In addition, the thrusts of the pair of linear motors32,33can be applied to the end surface28aand the end surface28bindependently.

The second drive apparatus31comprises a guide member37, which is long in the Y axial directions. The guide member37comprises a coil unit that functions as the stator of the voice coil motor36. The guide member37is disposed on the inner side of the countermass18. The guide member37is disposed on the −X side of the guide member35. The +Y and −Y side ends of the guide member37are fixed to the inner surface of the countermass18via prescribed fixed members.

A magnet unit, which functions as the slider of the voice coil motor36, is disposed on the −X side end of the mask stage main body27.

In the present embodiment, the slider provided to the −X side end of the mask stage main body27and the stator provided to the guide member37together form the moving magnet type voice coil motor36, which is capable of moving the mask stage main body27in the X axial directions.

By flowing an electric current to the coil unit of the stator of the voice coil motor36, the control apparatus3, based on both the electric current that flows through the coil unit and the magnetic field generated by the magnet unit of the slider, can generate an electromagnetic force (i.e., Lorentz's force) in the X axial directions. The control apparatus3can control the position of the mask stage1(i.e., the mask stage main body27) in the X axial directions by using the reaction force of that Lorentz's force to move the mask stage1in the X axial directions.

Thus, the mask stage drive apparatus15, which includes the first and second drive apparatuses30,31, can move the mask stage1in three directions: the X axial, Y axial, and θZ directions. The mask stage main body27holds the mask M using the mask holding part14and can move within the XY plane that includes the irradiation position of the exposure light EL (i.e., the illumination region IR of the illumination system IL).

The countermass18is a rectangular frame shaped member that has an opening wherein the mask stage1can be disposed and is capable of moving on the upper surface of the second plate13to offset the reaction force that accompanies the movement of the mask stage1. The countermass18offsets the reaction force that accompanies the movement of the mask stage1by moving in a direction opposite to the movement direction of the mask stage1.

In addition, the control apparatus3is capable of performing control such that a thrust in the Z axial directions is applied to each of the magnet units55by flowing currents of different directions to the coils52a,52bof each of the coil units51.

As shown inFIG. 5, if a thrust is applied to each of the magnet units55in, for example, the +Z direction, then each of the magnet units55will attempt to move in the +Z direction. In contrast, because the first member28is restrained by the air pads57such that a fixed clearance is maintained between the first member28and the guide surface13G, the first member28is pulled in the −Z direction by the air pads57and held such that the position of each of the portions57athat contact the air pads57does not change. In a plan view, the air pads57are disposed at positions different from the positions57aat which the magnet units55overlap; consequently, moments in the θY directions, using the portions at which the air pads57are provided as fulcrums, are applied to the side of each of the magnet units55opposite the corresponding air pad57in the X axial directions such that the +X side and −X side end surfaces provided to each of the magnet units55are the points of force application. Accordingly, in the present embodiment, the portions57aof the first member28at which the air pads57are provided constitute second positions.

In the present embodiment, the magnet units55are provided to the end surfaces28a,28bof the first member28in the X axial directions; moreover, the end surfaces28a,28b, which constitute the first positions, are provided such that they sandwich the portions57a(i.e., the second positions) of the first member28, which are the fulcrums, that contact the air pads57; consequently, the moments, wherein the magnet units55on both sides are the points of force application, are applied to the center part of the first member28in the X axial directions. Accordingly, a −Z direction force acts on the center part of the first member28in the X axial directions. This force bends the first member28in the −Z direction and, attendant therewith, the center part of the mounting surface45aof the mask holding part14in the X axial directions bends in the −Z direction. In the state wherein the mask M is mounted to the mounting surface45a, the center part of the mask M in the X axial directions bends in the −Z direction as the mounting surface45adeforms. Consequently, the position of the front surface of the mask M in the Z directions moves in the −Z direction.

Conversely, if a thrust is applied to each of the magnet units55in, for example, the −Z direction as shown inFIG. 6, then each of the magnet units55will attempt to move in the −Z direction. Consequently, based on a principle similar to that wherein the thrusts are applied in the +Z direction, moments around the θY directions, wherein the portions at which the air pads57are provided serve as the fulcrums, are applied to the sides of each of the magnet units55opposite the corresponding air pad57in the X axial directions such that the +X side and −X side end surfaces provided to the magnet units55are the points of force application. Because the magnet units55are provided to both end surfaces of the first member28in the X axial directions, moments, wherein the magnet units55on both sides serve as points of force application, are applied to the center part of the first member28in the X axial directions. The direction in which the force acts is opposite that of the case wherein the thrusts are applied in the +Z direction, and therefore a −Z direction force acts on the center part of the first member28in the X axial directions. As a result of this force, the first member28bends in the +Z direction and, attendant therewith, the center part of the mounting surface45aof the mask holding part14in the X axial directions bends in the +Z direction. In the state wherein the mask M is mounted to the mounting surface45a, the center part of the mask M in the X axial directions bends in the +Z direction as the mounting surface45adeforms. Consequently, the position of the front surface of the mask M in the Z directions moves in the +Z direction.

Thus, the mask stage drive apparatus (mask stage drive mechanism, correcting mechanism)15functions as a correcting mechanism that corrects the shape of the mounting surface45aof the mask stage1and thereby corrects warpage in the shape (deformation) of the mask M mounted to the mounting surface45a.

In addition, in the present embodiment as shown inFIG. 1, a focus and level detection system70is provided. The focus and level detection system70detects the surface position (i.e., the position in the Z axial, θX, and θY directions) of the front surface of the mask M. The focus and level detection system70comprises a light projecting system70a, which projects a detection light to the illumination region IR of the mask M held by the mask holding part14that is irradiated with the exposure light EL, and a light receiving system70b, that is capable of receiving the detection light via the mask M. The light projecting system70adiagonally projects the detection light to the front surface of the mask M. The light receiving system70breceives the detection light that is projected by the light projecting system70ato the front surface of the mask M and is then reflected thereby. The light receiving system70bis connected to the control apparatus3and supplies, as information regarding changes in the shape of the mounting surface, a signal based on the received light to a table T1of the control apparatus3. The information regarding changes in the shape of the mounting surface is stored as individual positional coordinates in, for example, the Z axial directions (e.g., Z1-Z7).

In addition, shape information regarding the pattern formed on the substrate P (i.e., information regarding the projected image of the projection optical system PL) is derived in advance either empirically or by simulation, or both. The image information is the information associated with the information regarding position of the illumination region IR of the mask M in the Z axial directions. Associating the positional information with the image information can be accomplished by associating the positional information with the kind of image obtained at each coordinate, for example, Z1-Z7, based on the pattern information obtained when exposures are performed while changing the position of the illumination region IR of the mask M in the Z axial directions from Z1through to Z7.

In addition, each piece of image information is examined to determine in advance whether it is suitable; namely, the suitability of each pattern is determined in advance, and the suitability data is stored as the table T1such that the suitability data is associated with the positional data Z1-Z7, as shown inFIG. 7. In the present embodiment, the table T1comprises data that correlates the information regarding changes in the shape of the mounting surface45aand the information regarding the projected image of the projection optical system PL. The table T1shows a case wherein the pattern is unsuitable at the positions that correspond to the positional data Z1, Z2, Z6, Z7and suitable at the positions that correspond to the positional data Z3-Z5.

Accordingly, the control apparatus3can obtain pattern suitability data with respect to desired positional data, as shown inFIG. 7. Conversely, positional data that corresponds to the pattern suitability data can also be obtained. Furthermore, as shown inFIG. 7, different tables T2, T3, . . . are prepared in advance in accordance with, for example, the mask types.

The following text explains one example of the operation of the exposure apparatus EX according to the present embodiment. The mask M is transported to the mask holding part14; in addition, the lower surface Mb of the mask M is chucked to the holding surfaces45and thereby the mask M is mounted to the mounting surface45a. In addition, the substrate P is transported to and held by the substrate holding part22. The control apparatus3starts the exposure of the substrate P in the state wherein the environment (including the temperature, the humidity, and the cleanliness level) of the internal space4has been adjusted by the chamber apparatus5.

The control apparatus3illuminates the mask M with the exposure light EL from the illumination system IL and exposes the substrate P with the exposure light EL, which travels through the mask M and the projection optical system PL, while moving the substrate P in one of the Y axial directions with respect to the projection region PR of the projection optical system PL and moving the mask M in the other Y axial direction with respect to the illumination region IR of the illumination system IL synchronized to the movement of the substrate P by operating the mask stage drive apparatus15and the substrate stage drive apparatus25. Thereby, the image of the pattern of the mask M is projected to the substrate P through the projection optical system PL.

When the lower surface Mb of the mask M is chucked to the holding surfaces45, there are cases wherein the shape of the mask M warps in the Z axial directions. If the exposure is started in this state, exposure failures, such as a reduction in the overlay accuracy of and the production of defects in the pattern formed on the substrate P, might occur.

Accordingly, in the present embodiment, an exposure is performed while the focus and level detection system70detects the position of the front surface of the mask M—particularly the illumination region IR—in the Z axial directions (i.e., detects information regarding the shape of the mounting surface) and, based on this positional information, corrects the position of the mask M in the Z axial directions. Specifically, based on the information regarding the position in the Z axial directions detected by the focus and level detection system70, the control apparatus3apprehends the suitability data in the table T1, which is stored in the control apparatus3.

If the apprehended suitability data constitutes a suitable pattern, then the control apparatus3continues the exposure operation without correcting the position of the mask M in the Z axial directions. However, if the apprehended suitability data constitutes an unsuitable pattern, then the control apparatus3retrieves the positional data that corresponds to stored suitability data for which the pattern is suitable and, based on that positional data, corrects the position of the mask M in the Z axial directions.

When the position of the mask M in the Z axial directions is corrected—for example, when the mask M must be moved in the +Z direction—control is performed such that a thrust in the −Z direction is applied to each of the magnet units55. In addition, if the mask M must be moved in the −Z direction, then control is performed such that a thrust in the +Z direction is applied to each of the magnet units55. The position of the mask M is corrected with every scan. Consequently, even if the warpage of the shape of the mask M is complex, the position of the illumination region IR in the Z axial directions can be corrected to a suitable position with each scan.

According to the present embodiment as explained above, the mask stage drive mechanism15can correct the shape of the mounting surface45a, and therefore the shape of the surface that contacts the mounting surface45a—namely, the shape of the mask M on the mounting surface45a—can be deformed to a desired shape by the mounting surface45a, whose shape has been corrected. Thereby, the warpage of the shape of the mask M on the mounting surface45acan be corrected.

Accordingly, the shape of the mask M on the mounting surface45acan be corrected so that, for example, the pattern formed on the mask M is focused on the surface (to be exposed) of a substrate P to be exposed.

For example, in the mask stage1having a configuration shown inFIG. 3andFIG. 4, by generating the Z thrust in a range of approximately 5 N to approximately 20 N with the mask stage drive apparatus15, the mounting surface45aof the mask holding part14can be deformed with a curvature (warpage) having an maximum amplitude in a range of approximately +100 nm (or −100 nm) to approximately +200 nm (or −200 nm). When the mask M is held on the mask holding part14, the mask M is supported so as to cover the first opening16; therefore, the part above the opening may be deformed with a curvature (warpage) in a direction of gravitational force (an optical axis direction of the exposure light EL). In this case, the projection optical system PL can have optical characteristics that can be set based on the predictive value of the curvature (warpage) of the mask M. However, when the value of the curvature of the mask M has poor repeatability from any case, or when the values of the curvature of some masks M are different from each other, an actual value may beyond an allowable range which has been set. For this case, in the present embodiment, the curvature (warpage) of the mounting surface45aof the mask holding part14can be adjusted so that the shape of the mask M can be changed to be within the allowable range. The cause is not limited to the mask M. When the value is beyond the allowable range because that the difference in dimension of the mounting surface45aor the like along with the machining accuracy for the exposure apparatus, the curvature (warpage) of the mounting surface45aof the mask holding part14can be also adjusted so that the shape of the mask M can be changed to be within the allowable range.

In the above-described embodiment, the feature of the present invention is applied to the mask stage; alternatively, the feature can be applied to the substrate stage2so that the shape of the substrate P can be corrected. In this case, the substrate P can be mounted on a substrate holding member having a plate shape, and the shape of the mounting surface of the substrate holding member can be adjusted. As the actuator for the correcting mechanism, a Z drive mechanism, which already has been provided, for focusing leveling can be used, or another actuator for a correcting mechanism can be provided.

The above text explained an embodiment of the present invention based on the drawings, but its specific constitution is not limited to these embodiments, and it is understood that variations and modifications may be effected without departing from the spirit and scope of the invention.

For example, the configuration of the correcting mechanism is not limited to one in the embodiments. In the abovementioned embodiment, a configuration is adopted wherein the magnet units55, which are constituent elements of the mask stage drive apparatus15, are disposed at two locations of the end surface28aof the first member28and two locations of the end surface28bof the first member28, but the present invention is not limited thereto; as shown inFIG. 8. For example, a configuration may be adopted wherein the magnet units55are disposed at four locations of the end surface28aof the first member28and four locations of the end surface28bof the first member28.

In addition, the number of locations of the magnet units55is not limited to four, and a configuration may be adopted wherein the number of locations is five or more or three. Thereby, the positions of the points of force application would increase and more complex moments would be applied to the mask stage1, thus increasing the accuracy with which the shape of the mask M is corrected.

In the embodiment, the magnet unit55provided at the end surface28aof the first member28forms a part of the linear motor32, and the magnet units55provided at the end surface28bof the first member28forms the part of the linear motor33. In this case, each of the linear motors32and33has two pairs of up- and down linear motor units; however, they are not limited to this configuration. For example, they each can have one pair of linear motor units.

In addition, the number of positions of points of force application on the magnet units55may be increased along with the number of air pads57. InFIG. 8, the air pads57are located at six positions, but naturally they may be located at more than six positions. Thereby, the number of fulcrum positions with respect to the points of force application would increase and, consequently, far more complex moments would be applied to the mask stage1, thereby increasing correction accuracy. In addition, the number of air pads57may also be three or fewer. Concentrating the fulcrums is advantageous in that it enables stable correction.

In addition, in the abovementioned embodiment, a configuration is adopted wherein the mask stage drive apparatus15, which moves the mask M along X and Y directions functions as a correcting mechanism that corrects the shape of the mounting surface45a, but the present invention is not limited thereto. For example, the correcting mechanism can be configured so that a mechanism, such as an actuator or an air bearing, can be separately provided that corrects the shape of the mounting surface45a.

In the embodiment, as a means (correcting mechanism) for generating a force, a linear motor or an air bearing is used; however, the means is not limited to this. A rotary motor, a magnetic bearing or the like, which can apply force to the mounting surface, can be used as the means.

In the above-described embodiment, the actuators or the like are substantially symmetrically disposed at both the end surfaces28aand28bof the first member28; however the configuration is not limited to this. For example, a first side of the first member28can be fixed (or disposed substantially without displacement), and an actuator can be disposed at a second side, so that the displacement can be generated at the second side to apply a force to the first member28and to change the shape of the first member28.

In addition, in the abovementioned embodiment, when the shape of the mounting surface45ais corrected, the amount of correction is adjusted based on data that correlates the information regarding changes in the shape of the mounting surface with information regarding the projected image of the projection optical system, but the present invention is not limited thereto. For example, the information regarding changes in the shape of the mounting surface (e.g., the quantity detected by the focus and level detection system70) or the information regarding the projected image of the projection optical system may be used independently to adjust the amount of correction. For example, when there is a difference from a predetermined state caused by a shape of one mask M or by a state where the mask M is held on the mounting surface45a, the correcting mechanism can be used without relation to the information regarding the projected image of the projection optical system.

The focus leveling control can be executed in cooperation with the correction of the shape of the mask with the correcting mechanism as described above, and additionally in cooperation with the positional control of the substrate P with the substrate stage driving apparatus25of the substrate stage2and the like (e.g., the drive for focusing leveling).

Furthermore, when the values of the curvature (warpage) differ between masks as described above, the correcting mechanism can correct the value to be within a substantially steady range (e.g., allowable range). In addition, in a case in which the irradiation of the exposure light EL or the like causes thermal deformation of the mask M and in which the shape of the mask M is changed from the desired state (desired shape), the shape of the mask M can be corrected by means of the correcting mechanism. In this case, the deformation amount of the mask M can be predicted based on the irradiation amount of the exposure light EL, so that the correction can be executed by means of the correcting mechanism while the exposure processing in order to compensate the thermal deformation of the mask M.

Furthermore, the substrate P in each of the embodiments discussed above is not limited to a semiconductor wafer for fabricating semiconductor devices, but can also be adapted to, for example, a glass substrate for display devices, a ceramic wafer for thin film magnetic heads, or the original plate of a mask or a reticle (i.e., synthetic quartz or a silicon wafer) used by an exposure apparatus.

The exposure apparatus EX can also be adapted to a step-and-scan type scanning exposure apparatus (i.e., a scanning stepper) that scans and exposes the pattern of the mask M by synchronously moving the mask M and the substrate P, as well as to a step-and-repeat type projection exposure apparatus (i.e., a stepper) that successively steps the substrate P and performs a full field exposure of the pattern of the mask M with the mask M and the substrate P in a stationary state.

Furthermore, when performing an exposure with a step-and-repeat system, the projection optical system is used to transfer a reduced image of a first pattern onto the substrate P in a state wherein the first pattern and the substrate P are substantially stationary, after which the projection optical system may be used to perform a full-field exposure of the substrate P, wherein a reduced image of a second pattern partially superposes the transferred first pattern in a state wherein the second pattern and the substrate P are substantially stationary (i.e., as in a stitching type full-field exposure apparatus). In addition, the stitching type exposure apparatus can also be adapted to a step-and-stitch type exposure apparatus that successively steps the substrate P and transfers at least two patterns onto the substrate P such that they are partially superposed.

In addition, the present invention can also be adapted to, for example, an exposure apparatus that combines on a substrate the patterns of two masks through a projection optical system by double exposing, substantially simultaneously, a single shot region on a substrate using a single scanning exposure, as disclosed in, for example, U.S. Pat. No. 6,611,316. In addition, the present invention can also be adapted to, for example, a proximity type exposure apparatus and a mirror projection aligner.

In addition, the exposure apparatus EX can also be adapted to a twin stage type exposure apparatus, which comprises a plurality of substrate stages, as disclosed in, for example, U.S. Pat. Nos. 6,341,007, 6,400,441, 6,549,269, 6,590,634, 6,208,407, and 6,262,796.

Furthermore, as disclosed in, for example, U.S. Pat. No. 6,897,963 and European Patent Application Publication No. 1713113, the present invention can also be adapted to an exposure apparatus provided with a substrate stage that holds the substrate, and a measurement stage whereon either a fiducial member (wherein a fiducial mark is formed) or various photoelectric sensors, or both, are mounted. In addition, the exposure apparatus can be adapted to an exposure apparatus that comprises a plurality of substrate stages and measurement stages.

In addition, the present invention can also be adapted to an immersion exposure apparatus that exposes the substrate with exposure light through a liquid, as disclosed in, for example, PCT International Publication No. WO99/49504. In addition, the present invention can also be adapted to an EUV light source exposure apparatus that exposes the substrate P with extreme ultraviolet light.

The type of exposure apparatus EX is not limited to a semiconductor device fabrication exposure apparatus that exposes the substrate P with the pattern of a semiconductor device, but can also be widely adapted to exposure apparatuses used to fabricate, for example, liquid crystal devices or displays, and to exposure apparatuses used to fabricate thin film magnetic heads, image capturing devices (CCDs), micromachines, MEMS devices, DNA chips, or reticles and masks.

Furthermore, in each of the abovementioned embodiments, the positional information of the mask stage1and the substrate stage2is measured using the interferometer system19, but the present invention is not limited thereto and, for example, an encoder system may be used that detects a scale (i.e., a diffraction grating) provided to each stage. In this case, the system would preferably be configured as a hybrid system that is provided with both an interferometer system and an encoder system; moreover, it would be preferable to use the measurement results of the interferometer system to calibrate the measurement results of the encoder system. In addition, the positions of the stages may be controlled by switching between the interferometer system and the encoder system, or by using both.

In addition, in each of the embodiments discussed above, an ArF excimer laser may be used as a light source apparatus that generates ArF excimer laser light, which serves as the exposure light EL; however, as disclosed in, for example, U.S. Pat. No. 7,023,610, a harmonic generation apparatus may be used that outputs pulsed light with a wavelength of 193 nm and that comprises: an optical amplifier part, which has a solid state laser light source (such as a DFB semiconductor laser or a fiber laser), a fiber amplifier, and the like; and a wavelength converting part. Moreover, in the abovementioned embodiments, both the illumination region and the projection region are rectangular, but they may be some other shape, for example, arcuate. Furthermore, in each of the embodiments discussed above, an optically transmissive mask is used wherein a prescribed shielding pattern (or phase pattern or dimming pattern) is formed on an optically transmissive substrate; however, instead of such a mask, a variable pattern forming mask (also called an electronic mask, an active mask, or an image generator), wherein a transmissive pattern, a reflective pattern, or a light emitting pattern is formed based on electronic data of the pattern to be exposed, may be used as disclosed in, for example, U.S. Pat. No. 6,778,257. The variable pattern forming mask comprises a digital micromirror device (DMD), which is one kind of non-emissive type image display device (e.g., a spatial light modulator). In addition, the variable forming mask is not limited to a DMD, and a non-emissive type image display device, which is explained below, may be used instead. Here, the non-emissive type image display device is a device that spatially modulates the amplitude (i.e., the intensity), the phase, or the polarization state of the light that travels in a prescribed direction; furthermore, examples of a transmissive type spatial light modulator include a transmissive type liquid crystal display (LCD) as well as an electrochromic display (ECD). In addition, examples of a reflecting type spatial light modulator include a DMD, which was discussed above, as well as a reflecting mirror array, a reflecting type LCD, an electrophoretic display (EPD), electronic paper (or electronic ink), and a grating light valve.

In addition, instead of a variable pattern forming mask that comprises a non-emissive type image display device, a pattern forming apparatus that comprises a self luminous type image display device may be provided. In this case, an illumination system is not necessary. Here, examples of a self luminous type image display device include a cathode ray tube (CRT), an inorganic electroluminescence display, an organic electroluminescence display (OLED: organic light emitting diode), an LED display, an LD display, a field emission display (FED), and a plasma display (PDP: plasma display panel). In addition, a solid state light source chip that has a plurality of light emitting points or that creates a plurality of light emitting points on a single substrate, a solid state light source chip array wherein a plurality of chips are arrayed, or the like may be used as the self luminous type image display device that constitutes the pattern forming apparatus, and the pattern may be formed by electrically controlling the solid state light source chip or chips. Furthermore, it does not matter whether the solid state light source device is inorganic or organic.

In this case, tables T1, T2, T3, . . . , which correspond to each of the masks, are prepared in advance in the control apparatus3, and thereby warpage can be corrected regardless of the mask type.

Each of the embodiments discussed above explained an exemplary case of an exposure apparatus that comprises the projection optical system PL, but the present invention can be adapted to an exposure apparatus and an exposing method that do not use the projection optical system PL. Thus, even if the projection optical system PL were not used, then the exposure light would be radiated to the substrate through an optical member, such as a lens.

As described above, the exposure apparatus EX of the embodiments in the present application is manufactured by assembling various subsystems, including each constituent element recited in the claims of the present application, so that prescribed mechanical, electrical, and optical accuracies are maintained. To ensure these various accuracies, adjustments are performed before and after this assembly, including an adjustment to achieve optical accuracy for the various optical systems, an adjustment to achieve mechanical accuracy for the various mechanical systems, and an adjustment to achieve electrical accuracy for the various electrical systems. The process of assembling the exposure apparatus EX from the various subsystems includes, for example, the mechanical interconnection of the various subsystems, the wiring and connection of electrical circuits, and the piping and connection of the atmospheric pressure circuit. Naturally, prior to performing the process of assembling the exposure apparatus EX from these various subsystems, there are also the processes of assembling each individual subsystem. When the process of assembling the exposure apparatus EX from the various subsystems is complete, a comprehensive adjustment is performed to ensure the various accuracies of the exposure apparatus EX as a whole. Furthermore, it is preferable to manufacture the exposure apparatus EX in a clean room wherein, for example, the temperature and the cleanliness level are controlled.

As shown inFIG. 9, a micro-device, such as a semiconductor device, is manufactured by: a step201that designs the functions and performance of the micro-device; a step202that fabricates the mask M (i.e., a reticle) based on this designing step; a step203that manufactures the substrate P, which is the base material of the device; a substrate processing step204that comprises a substrate process (i.e., an exposing process) that includes, in accordance with the embodiments discussed above, exposing the substrate P with the exposure light EL that passes through the mask M and developing the exposed substrate P; a device assembling step205(which includes fabrication processes such as dicing, bonding, and packaging processes); an inspecting step206; and the like.

Furthermore, the features of each of the embodiments discussed above can be combined as appropriate. In addition, each disclosure of every Japanese published patent application and U.S. patent related to the exposure apparatus recited in each of the embodiments, modified examples, and the like discussed above is hereby incorporated by reference in its entirety.