1. Field of the Invention
The present invention relates to a stage apparatus, an exposure apparatus, and a device fabricating method.
2. Related Art
In the photolithographic process—which is one of the processes used in fabricating various devices, such as semiconductor devices, liquid crystal display devices, image capturing devices like charge coupled devices (CCDs), and thin film magnetic heads—an exposure apparatus is used to transfer a pattern, which is formed in a mask or a reticle (herein called a mask when referred to generically), through a projection optical system to a glass plate or a substrate (e.g., a wafer) coated with a photoresist. Because with this exposure apparatus it is necessary to position the substrate at an exposure position with high accuracy, the substrate is held on a substrate holder by, for example, vacuum chucking, and the substrate holder is fixed on a substrate table.
In recent years, to improve throughput (i.e., the number of substrates able to undergo the exposing process per unit of time) demand has called for moving the substrate at higher speeds. In addition, as the fineness of patterns transferred to substrates has increased, demand has called for positioning the substrate with high accuracy without affecting, for example, the accuracy of a mechanical guide surface. Furthermore, to reduce the number of occasions on which maintenance is required and to extend the operating time of the exposure apparatus, there is also a demand for extending life by avoiding mechanical friction. To satisfy these demands, a stage apparatus that positions the substrate by driving the substrate table, whereon the substrate is mounted, noncontactually in two-dimensional directions is under development. As an example of a drive source for a non-contactually driven stage apparatus, a planar motor is known that has a structure wherein, for example, two variable reluctance drive type linear pulse motors are coupled.
The mainstream structure of the variable reluctance drive type planar motors mentioned above currently couples two variable reluctance drive type linear pulse motors, as in a Sawyer motor. A variable reluctance drive type linear pulse motor comprises, for example, a stator, which comprises a plate shaped magnetic body wherein irregularly shaped teeth are formed at equal intervals in the longitudinal directions, and a slider, which opposes the irregularly shaped teeth of the stator and wherein multiple armature coils, which have irregular parts out of phase with the irregularly shaped teeth, are coupled via permanent magnets; furthermore, a variable reluctance drive type linear pulse motor is a motor that attempts to minimize at every point in time the reluctance between the stator and the slider and uses the generated force to drive the slider.
In addition, in recent years, planar motor apparatuses have been proposed (refer to Patent Document 1-3); each of these planar motor apparatuses comprises, for example, a fixed part, which comprises coils arrayed two dimensionally, and a movable part, which comprises permanent magnets arrayed two dimensionally; in addition, by using the Lorentz's force generated by the flowing of electric currents to the coils, each of these planar motor apparatuses two dimensionally drives the movable part with respect to the fixed part (refer to Japanese Unexamined Patent Application Publication No. H11-164543, Japanese Unexamined Patent Application Publication No. 2003-224961, and U.S. Pat. No. 5,677,758).
Nevertheless, the related art discussed above has the following problems.
With regard to the abovementioned movable part, measuring apparatuses, such as regular laser interferometers, are used to measure position (as well as velocity and the like); however, disposing the interferometers such that position can be measured over the movable part's entire range of motion significantly increases cost, which is a problem.
In particular, as when a direct driven type linear motor is used, the movable part in the planar motor apparatus discussed above is not configured such that the relative position between the slider and the stator in a linear motor can be monitored. Consequently, demand exists for a plan capable of measuring the position of the movable part without inviting a significant increase in cost.
A purpose of some aspects of the present invention is to provide a stage apparatus, an exposure apparatus, and a device fabricating method capable of measuring the position of a moving body of a planar motor apparatus over its entire range of motion without inviting a significant increase in cost.
A first aspect of the invention provides a stage apparatus that has a planar motor apparatus that comprises a fixed part, which has a prescribed movement surface, and a first movable body, which is capable of moving along the movement surface in a plurality of directions that includes a first direction; said stage apparatus comprising: a substage that, in synchrony with the movement of the first movable body, moves in the first direction with respect to the movement surface; a first measuring apparatus, at least part of which is provided to the substage, that detects information related to the relative position between the substage and the movement surface in the first direction; and a second measuring apparatus, at least part of which is provided to the substage, that detects information related to the relative position between the substage and the first movable body in a second direction, which are substantially orthogonal to the first direction and follow along the movement surface.
According to the first aspect of the present invention, with regard to the position of the first movable body in the first direction, it can be said that, because the substage moves synchronously with the first movable body, if the relative position between the substage and the first movable body is set to a certain value beforehand, then both are in a prescribed relationship. Accordingly, using the first measuring apparatus to detect the information related to the relative position between the substage and the movement surface makes it possible to obtain information related to the relative position between the first movable body and the movement surface in the first direction. In addition, with regard to the position of the first movable body in the second direction, the relative position between the substage and the movement surface are in a relationship that is prescribed beforehand. Accordingly, using the second measuring apparatus to detect the information related to the relative position between the substage and the movement surface makes it possible to obtain both information related to the relative position between the first movable body and the movement surface in the second direction and information related to the relative position in the θz direction. Furthermore, if a configuration is adopted such that the second measuring apparatus can also detect the information related to the relative position between the substage and the first movable body in the first direction, then the information related to the relative position between the first movable body and the movement surface in the first direction can be derived with higher accuracy.
Thus, in the first aspect, it is possible to use the first measuring apparatus, the second measuring apparatus, and the positional relationship between the substage and the movement surface to obtain the information related to the position of the first movable body over its entire range of motion, which makes it possible to avoid any insignificant increase in cost.
A second aspect of the invention provides an exposure apparatus that comprises a stage apparatus as recited above.
Because the second aspect comprises the abovementioned stage apparatus, it is possible to measure the information related to the position of the moving body, namely, the substrate and the like held by the moving body, without inviting a significant increase in cost.
A third aspect of the invention provides a device fabricating method wherein an exposure apparatus as recited above is used.
In the third aspect, because the exposure apparatus minimizes any increase in cost, using it to fabricate a device also makes it possible to minimize any increase in the cost of the device.
Some aspects of the present invention make it possible to measure the position of a moving body of a planar motor apparatus over its entire range of motion without inviting a significant increase in cost.
The following text explains embodiments of a stage apparatus, an exposure apparatus, and a device fabricating method according to the present invention, referencing
Furthermore, in the explanation below, an XYZ orthogonal coordinate system is defined in the figures where needed, and the positional relationships of members are described referencing this system. The XYZ orthogonal coordinate system is defined such that the X axis and the Z axis are parallel to the paper surface, and the Y axis is perpendicular to the paper surface. The XYZ coordinate system in the figures is actually set such that the XY plane is parallel to a horizontal plane, and the Z axis is actually set in the vertically upward direction. In addition, during an exposure, the synchronous movement directions (i.e., the scanning directions) of the wafer W and the reticle R are set in the Y directions.
As shown in
The illumination optical system ILS shapes the exposure light emitted from a light source unit (not shown)—for example, a laser light source such as an ultrahigh pressure halogen lamp or an excimer laser—uniformizes the luminous flux intensity distribution, and irradiates a rectangular (or arcuate) illumination area IAR on the reticle R with a uniform luminous flux intensity. The reticle stage RST is configured such that a stage movable part 11 is provided on a reticle base (not shown); furthermore, during an exposure, the stage movable part 11 moves at a prescribed scanning velocity on the reticle base in prescribed scanning directions.
In addition, the reticle R is held to an upper surface of the stage movable part 11 by, for example, vacuum chucking. An exposure light through-hole (not shown) is formed below the reticle R of the stage movable part 11. A reflecting mirror 12 is disposed at an end part of the stage movable part 11. A laser interferometer 13 detects the position of the stage movable part 11 by measuring the position of the reflecting mirror 12. The detection results of the laser interferometer 13 are output to a stage control system SCS. The stage control system SCS drives the stage movable part 11 based on the detection results of the laser interferometer 13 and a control signal from the main control apparatus MCS, which is based on the travel position of the stage movable part 11. Furthermore, although not shown in
The projection optical system PL is a reduction optical system wherein, for example, the reduction magnification is α (α is, for example, four or five); furthermore, the projection optical system PL is disposed below the reticle stage RST, and the directions of an optical axis AX thereof are set in the Z axial directions. Here, a dioptric system, which comprises multiple lens elements disposed at prescribed intervals in the directions of the optical axis AX such that the dioptric system has a telecentric optical layout, is used. Furthermore, appropriate lens elements are selected in accordance with the wavelength of the light emitted from the light source unit. When the illumination area IAR of the reticle R is irradiated by the abovementioned illumination optical system ILS, a reduced image (i.e., a partial inverted image) of the pattern inside the illumination area IAR of the reticle R is formed on the wafer W in an exposure area IA, which is conjugate with the illumination area IAR.
Because the drive apparatuses 15 provided to the stage units WST1, WST2 can be individually driven, the stage units WST1, WST2 can be individually moved in arbitrary directions within the XY plane.
In the example shown in
Here, each of the drive apparatuses 15 is a planar motor that comprises: a fixed part 16, which is provided to (i.e., embedded in) an upper part of the base member 14; and a movable part 17 (i.e., a first movable body), which is fixed to a bottom part of the corresponding stage unit WST1, WST2 (i.e., on the side of the surface that opposes the base) and moves along a movement surface 16a on the fixed part 16. In addition, the movable part 17, the base member 14, and the drive apparatus 15 constitute a planar motor apparatus. Furthermore, in the explanation below, each of the abovementioned drive apparatuses 15 is called the planar motor apparatus 15 for the sake of convenience.
The wafers W are fixed on the stage units WST1, WST2 by, for example, vacuum chucking. The side surfaces of the stage units WST1, WST2 (i.e., second stages 28, which are discussed below) are reflecting surfaces that reflect laser beams from a laser interferometer 18. The laser interferometer 18, which is disposed externally, continuously detects the positions of the stage units WST1, WST2 within the XY plane with a resolving power of, for example, approximately 0.5-1.0 nm.
Furthermore, in
Positional information (and velocity information) about the stage units WST1, WST2 is supplied to the stage control system SCS and, via the stage control system SCS, to the main control apparatus MCS. In accordance with an instruction from the main control apparatus MCS, the stage control system SCS controls via the planar motor apparatuses 15 the movement of each of the stage units WST1, WST2 within the XY plane based on the positional information (and the velocity information) about each of the stage units WST1, WST2.
The configuration of the wafer stage WST will now be explained.
As shown in
The core members 22 are arrayed on the base member 14 such that the tip parts of their head parts 22a are included in substantially one plane. At this time, in each of the core members 22, the support post part 22b is electrically connected to the base member 14. A separator 23, which comprises a nonmagnetic body, is provided between the head parts 22a of the core members 22. The separator 23 is formed from, for example, SUS or a ceramic material and is used to ensure that a magnetic circuit is not formed between adjacent core members 22.
The height of the upper part of the separator 23 is set such that matches that of the tip parts of the head parts 22a of the core members 22, and consequently the upper surface (i.e., the movement surface) of the fixed part 16 is substantially a flat surface. In addition, the provision of the separator 23 between the head parts 22a of the core members 22 creates a space, which is interposed in the vertical directions between the base member 14 on one side and the head parts 22a of the core members 22 and the separator 23 on the other side. A coolant is introduced into this space, which makes it possible to cool the coils 21.
A guide member 24 is provided to the upper surface of the fixed part 16. The guide member 24 is formed from a nonmagnetic body and serves as a guide plate that causes the stage units WST1, WST2 to move within the XY plane. The guide member 24 is formed by thermally spraying, for example, alumina (Al2O3) onto the flat upper surface of the fixed part 16 and then blowing highly pressurized gas against this metal surface.
A three-phase alternating current, which comprises a U phase, a V phase, and a W phase, is supplied to the coils 21 that are provided to the fixed part 16. The electric currents of each of these phases of all of the coils 21 arrayed within the XY plane are impressed in a prescribed order and with a prescribed timing, which makes it possible to move the stage units WST1, WST2 in desired directions at desired velocities.
In
Each of the movable parts 17, which constitute part of the wafer stage WST, comprises a first stage 25, permanent magnets 26, air pads 27, a second stage 28 (i.e., a second movable body), a horizontal drive mechanism 29, and vertical drive mechanisms 30. The permanent magnets 26 and the air pads 27 are arrayed regularly on the bottom surface of the first stage 25. It is possible to use as the permanent magnets 28 neodymium-iron-cobalt magnets, aluminum, nickel, and cobalt (Alnico) magnets, ferrite magnets, samarium-cobalt magnets, or rare earth magnets such as neodymium-iron-boron magnets.
The second stage 28 is supported on the first stage 25 via the vertical drive mechanisms 30. Here, the vertical drive mechanisms 30 comprise support mechanisms 30a, 30b, 30c (refer to
The horizontal drive mechanisms 29 comprise drive mechanisms 29a, 29b, 29c (refer to
Returning to
Furthermore, although not shown in
The detection apparatuses 60A, 60B comprise substages 61A, 61B, which move in synchrony with the stage units WST1, WST2 in the Y directions. Here, the structures of the substages 61A, 61B are the same, and consequently constituent elements of the substage 61B that are identical to those of the substage 61A are assigned the same symbols (in addition, the letter B is appended to matched elements where appropriate); furthermore, hereinbelow, the substage 61A alone is representatively explained.
The substage 61A comprises: a slider 62, which moves in the Y directions along the −X side end edge of the fixed part 16 (i.e., the base member 14); and support parts 63, 64, which extend from both ends of the slider 62 in the X directions on the movement surface 16a of the fixed part 16. The slider 62 and a stator 65, which is provided to a side surface 16b of the fixed part 16 such that it extends in the Y directions, constitutes a linear motor LM, which drives the slider 62 in the Y directions by virtue of the electromagnetic interaction with the stator 65. The linear motor LM may be a moving coil type or a moving magnet type system, the drive of which is controlled by the stage control system SCS. Vacuum preloaded air pads 66, which are spaced apart in the Y and Z directions, are provided to the slider 62. The air pads 66 blow air toward the side surface 16b of the fixed part 16, and thereby the slider 62 is supported noncontactually such that it is capable of moving in the Y directions with respect to the fixed part 16 in the state wherein a clearance of, for example, approximately several microns is maintained.
In addition, an encoder head 67 (i.e., a first measuring apparatus), which detects the relative position of the substage 61A with respect to the fixed part 16 in the Y directions (i.e., first directions), is provided to the slider 62. The encoder head 67 detects the position of the substage 61A with respect to the fixed part 16 in the Y directions by reading an encoder scale 68 (i.e., a first member to be detected), which is provided integrally with the stator 65 to the fixed part 16, and outputs the detection result to the stage control system SCS.
The support parts 63, 64 are provided parallelly such that they are spaced apart by a spacing approximately several millimeters larger than the dimension of the stage unit WST1 in the Y directions. Namely, the stage unit WST1 is capable of relative motion with respect to the substage 61A in the Y directions with a range of motion of approximately several millimeters and is capable of relative motion in the X directions with a range of motion slightly larger than that of the Y directions. In addition, the lower surfaces of the support parts 63, 64 are provided with air pads 69, 70, respectively (only the air pad 70 is shown in
Encoder heads 71, 72 (i.e., second measuring apparatuses) are provided to the tip parts of the support parts 63, 64, respectively, such that they are positioned on opposite sides of the stage unit WST1 in the Y directions. The encoder heads 71, 72 read encoder scales 73, 74 (i.e., second members to be detected), which extend in the X directions and are provided to the side surfaces of the first stage 25 of the stage unit WST1 such that they oppose the encoder heads 71, 72. Thereby, the position of the stage unit WST1 with respect to the substage 61A in the X directions is detected, and the detection result is output to the stage control system SCS.
A sensor 80 is provided to at least one of the support parts 63, 64 (in
In addition, the support part 64 comprises a piping tray that holds cables and tubes for supplying various service utilities to the stage unit WST1. The cables and tubes include, for example, piping for supplying and exhausting a coolant for temperature adjustment to the motors (i.e., actuators such as VCMs) provided to the stage unit WST1, piping (e.g., the tubes 41, 42 discussed above) that supply air used in the air bearings, piping that supplies negative pressure (i.e., a vacuum) for chucking the wafer W, wiring for supplying electric power to the various sensors, and system wiring for supplying various control signals and detection signals; furthermore, these cables and tubes are provided to and disposed in the various drive equipment and control equipment. In the present embodiment, as shown in
Because the piping system 75 has a bent part that is capable of variable movement in the X directions, the piping system 75 does not apply any force in the X directions between the support part (e.g., the support part 64) of the substage 61 and the piping holding part 76 (namely, the first stage 25). In addition, because the substage 61 and the first stage 25 move synchronously in the Y directions, the distance between them is fixed at a prescribed value. Consequently, the piping system 75 also does not apply any force in the Y directions between the support part (e.g., the support part 64) of the substage 61 and the piping holding part 76 (namely, the first stage 25). Accordingly, the first stage 25 is unaffected by the force (i.e., the drag) of the piping system 75, even if the first stage 25 moves in the X or Y directions. Consequently, it is possible to suppress any disturbance caused by these drags.
When the stage units WST1, WST2, which are configured as explained above, are moved, a driving method similar to the one used in the well-known linear motor, which drives via a three-phase alternating current, can be employed. Namely, it is conceivable that the stage units WST1, WST2 comprise linear motors configured such that they are moveable in the X directions and linear motors configured such that they are moveable in the Y directions; in such a case, if the stage units WST1, WST2 were to be moved in the X directions, then the same three-phase alternating current would be applied to each of the coils 21 arrayed in the X directions of the linear motors configured such that they are moveable in the X directions. In addition, if the stage units WST1, WST2 were to be moved in the Y directions, then the same three-phase alternating current would be applied to each of the coils 21 arrayed in the Y directions of the linear motors configured such that they are moveable in the Y directions.
In addition, during scanning, part of the pattern image of the reticle R is projected to the exposure area IA, and, synchronized to the movement of the reticle R with respect to the projection optical system PL at a velocity V in the −X direction (or the +X direction), the wafer W moves at a velocity β·V (where β is the projection magnification) in the +X direction (or the −X direction). When the exposing process for one shot region is complete, the main control apparatus MCS steps the stage unit WST1 and moves the next shot region to the scanning start position. Subsequently, the same exposing process is performed sequentially on each of the shot regions using the step-and-scan type system.
Here, when the stage units WST1, WST2 have moved on the base member 14 (i.e., on the fixed part 16), the laser interferometer 18 (18AX, 18AY, 18BX, 18BY) detects the positions (and the velocities, etc.) of the stage units WST1, WST2 as the positions (and the velocities, etc.) of the second stages 28. In addition, for example, when the exposing process is complete and the stage unit WST1 is to be moved to the loading position to replace the wafer, the second stage 28 may leave the measurable range of the laser interferometer 18. For example, when the stage units WST1, WST2 alternate between the exposing process and the wafer replacement process, the laser interferometers 18AY, 18BY are incapable of measuring the positions of at least the stage units WST1, WST2 in the Y directions when the stage units WST1, WST2 have moved on the fixed part 16 in the X directions to the position at which they are interposed between the laser interferometers 18AY, 18BY, as shown in
Accordingly, the position of the stage unit WST1 in the Y directions is measured with an accuracy of, for example, the micron order by the measurement of the encoder scale 68 performed by the encoder head 67 and the measurement performed by the sensor 80. Namely, when the stage unit WST1 moves on the base member 14 (i.e., the fixed part 16), the stage unit WST1 and the substage 61A move synchronously. At this time, the position of the substage 61 can be derived by using the encoder head 67 to measure the encoder scale 68. Furthermore, the relative position between the substage 61A and the stage unit WST1 (i.e., the first stage 25) is derived by the measurement the sensor 80 performs. Based on both of these measurement values, the relative position in the Y directions between the base member 14 (i.e., the fixed part 16) and the stage unit WST1 can be derived. In addition, using the sensor 80, driving force of the linear motor LM or the planar motor 17 may be controlled so as to, for example, control the gap between the substage 61A and the stage unit WST1 so that they do not collide. The present embodiment is configured such that the sensor 80 is provided separately from the encoder (i.e., the combination of the encoder heads 71, 72 and the encoder scales 73, 74), but both may be used in combination by a single apparatus (e.g., the second measuring apparatus).
When the stage unit WST1 moves on the base member 14 (i.e., on the fixed part 16) in the X directions, it moves along the gap between the support parts 63, 64; however, at this time, the position of the stage unit WST1 in the X directions with respect to the substage 61A (i.e., the encoder heads 71, 72) is detected by the measurement of the encoder scales 73, 74 via the encoder heads 71, 72, respectively. In addition, the position in the rotational directions around the Z axis is also detected by deriving the difference in the measurement results the encoder heads 71, 72 produce.
Accordingly, the substage 61A maintains a substantially constant position in the X directions with respect to the fixed part 16; in addition, the positions of the encoder heads 71, 72 in the substage 61A are also constant. Consequently, based on the measurement results of the encoder heads 71, 72, the position of the stage unit WST1 in the X directions with respect to the fixed part 16 and the position of the stage unit WST1 in the rotational directions around the Z axis are detected. Accordingly, even if the stage unit WST1 leaves the measurement range of the laser interferometer 18, the positions of the stage unit WST1 in the X directions, the Y directions, and the rotational directions around the Z axis are detected based on the measurement results of the encoder heads 67, 71, 72.
The present embodiment as explained above provides the substages 61A, 61B, which move synchronously with the stage units WST1, WST2 in the Y directions; in addition, the encoder heads 67, 71, 72 are provided to the substages 61A, 61B and capable of detecting the positions of the stage units WST1, WST2; therefore, even when the planar motor apparatuses 15 are used to drive the stage units WST1, WST2 and it is difficult to use the laser interferometers 18 to measure the positions of the stage units WST1, WST2 across their entire ranges of motion, the positions of the stage units WST1, WST2 can be measured easily compared with the case wherein the laser interferometers and the like are provided separately; moreover, their measurement does not invite a significant increase in cost. In particular, in the present embodiment, because the encoder heads 67, 71, 72 and the encoder scales 68, 73, 74 used to measure the positions are easy to install, they make a significant contribution to reducing costs and improving work efficiency. In addition, in the present embodiment, the encoder heads 71, 72 provided on opposite sides of the stage unit WST1 can measure not only the position of the stage unit WST1 in the X directions, but also the position of the stage unit WST1 in the rotational directions around the Z axis.
In addition, in the present embodiment, the substages 61A, 61B have piping tray functions that hold the piping systems 75; consequently, separately providing a stage that holds the piping systems and moves synchronously with the stage units WST1, WST2 is no longer necessary, and this can contribute to reductions in the size and cost of the apparatus. In addition, because, in the present embodiment, the substages 61A, 61B hold the piping systems 75 and move synchronously with the stage units WST1, WST2, it is possible to isolate disturbances, such as the drag that attends the deformation of the piping systems and the microvibrations transmitted via the piping systems 75, and to improve the controllability of the position with respect to the stage units WST1, WST2. Accordingly, regarding the exposure apparatus 10, which comprises the wafer stage WST, it is possible to control in an effectively dampened state and with high safety the position with respect to the wafer W and the velocity during a scanning exposure, and consequently accuracy related to the exposing process, such as overlay accuracy, can be reliably maintained.
The above text explained the preferred embodiments according to the present invention, referencing the attached drawings, but it is obvious that the present invention is not limited to these embodiments. Each of the constituent members, shapes, and combinations described in the embodiments discussed above are merely exemplary, and it is understood that variations and modifications based on, for example, design requirements may be effected without departing from the spirit and scope of the invention.
For example, the abovementioned embodiments explained an exemplary case of a so-called moving magnet type wafer stage WST, wherein permanent magnets 26 are provided to the movable part 17 of the stage unit WST1 and coils 21 are provided to the fixed part 16. Nevertheless, the present invention can also be adapted to a so-called moving coil type wafer stage, wherein coils are provided to a movable part of the stage unit and permanent magnets are provided to a fixed part. In addition, the abovementioned embodiments explained a case wherein the present invention is adapted to the wafer stage WST, but the present invention can also be adapted to the reticle stage RST, as well as to both the reticle stage RST and the wafer stage WST.
In addition to a step-and-scan type scanning exposure apparatus (i.e., a scanning stepper) that scans and exposes the pattern of the reticle R by synchronously moving the reticle R and the wafer W, the exposure apparatus 10 can also be adapted to a step-and-repeat type projection exposure apparatus (i.e., a stepper) that exposes the full pattern of the reticle R with the reticle R and the wafer W in a stationary state and then sequentially steps the wafer W. In addition, the present invention can be adapted to a step-and-stitch system exposure apparatus that partially and superimposingly transfers at least two patterns onto the wafer W.
In addition, the substrate of the abovementioned embodiments is not limited to a semiconductor wafer for fabricating semiconductor devices and can also be adapted to, for example, a glass substrate for a display device, a ceramic wafer for a thin film magnetic head, an original plate (e.g., synthetic quartz, silicon wafer) of a mask or a reticle used by an exposure apparatus, or a film member. In addition, the shape of the substrate is not limited to a circle and may be another shape, for example, a rectangle.
In addition, a KrF excimer laser (248 nm), an ArF excimer laser (193 nm), an F2 laser (157 nm), as well as a g-line (436 nm) or i-line (365 nm) light source can be used as the light source of the exposure apparatus to which the present invention is adapted. Furthermore, the magnification of the projection optical system is not limited to a reduction system, but may also be a unity magnification system or an enlargement system. In addition, the abovementioned embodiments described an example of a dioptric projection optical system, but the present invention is not limited thereto. For example, the optical system may be catadioptric or dioptric.
In addition, the exposure apparatus of the present invention can also be adapted to an exposure apparatus that is used in the fabrication of semiconductor devices and that transfers a device pattern onto a semiconductor substrate, an exposure apparatus that is used in the fabrication of liquid crystal display devices and that transfers a circuit pattern onto a glass plate, an exposure apparatus that is used in the fabrication of thin film magnetic heads and that transfers a device pattern onto a ceramic wafer, an exposure apparatus that is used in the fabrication of image capturing devices such as CCDs, and the like.
In addition, the present invention is adapted to a so-called immersion exposure apparatus wherein a liquid locally fills the space between the projection optical system and the substrate, which is exposed through the liquid, and such an immersion exposure apparatus is disclosed in PCT International Publication WO 99/49504. Furthermore, the present invention can also be adapted to an immersion exposure apparatus that performs exposures in a state wherein the entire front surface of the substrate to be exposed is immersed in a liquid, as disclosed in, for example, Japanese Unexamined Patent Application Publication No. H6-124873, Japanese Unexamined Patent Application Publication No. H10-303114, and U.S. Pat. No. 5,825,043.
In addition, the abovementioned embodiments present an example of a configuration wherein a plurality of stage units (e.g., two) is provided, but the present invention is not limited thereto; for example, it is possible to adopt a configuration wherein a singular stage unit is provided.
In addition, instead of providing a plurality of stage units, the present invention can also be adapted to an exposure apparatus provided with a substrate stage that holds the substrate and a measurement stage that measures exposure-related information and whereon a fiducial member (wherein a fiducial mark is formed) and various photoelectric sensors are mounted, as disclosed in Japanese Unexamined Patent Application Publication No. H11-135400 (corresponding U.S. Patent Application Serial No. 1999/23692) and Japanese Unexamined Patent Application Publication No. 2000-164504 (corresponding U.S. Pat. No. 6,897,963).
In addition to a step-and-scan type scanning exposure apparatus (i.e., a scanning stepper) that scans and exposes the pattern of a mask by synchronously moving the reticle R, which serves as the mask, and the wafer W, which serves as the substrate, the exposure apparatus 10 can also be adapted to a step-and-repeat type projection exposure apparatus (i.e., a stepper) that performs a full-field exposure of the pattern of the mask in a state wherein the mask and the substrate are stationary, and then sequentially steps the substrate.
Furthermore, when performing an exposure with a step-and-repeat system, the projection optical system may be used to transfer a reduced image of a first pattern onto the substrate in a state wherein the first pattern and the substrate are substantially stationary and then to perform a full-field exposure of the substrate wherein a reduced image of a second pattern partially superposes the first pattern (as in a stitching type full-field exposure apparatus) in a state wherein the second pattern and the substrate are substantially stationary. In addition, the stitching type exposure apparatus can also be adapted to a step-and-stitch type exposure apparatus that transfers at least two patterns onto the substrate such that they partially overlap and sequentially steps the substrate P.
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 is not used, the exposure light can be radiated to the substrate through optical members, such as lenses, and an immersion space can be formed in a prescribed space between the substrate and those optical members.
The type of exposure apparatus 10 is not limited to a semiconductor device fabrication exposure apparatus that exposes the substrate with the pattern of a semiconductor device, but can also be widely adapted to an exposure apparatus that is used for fabricating, for example, liquid crystal display devices or displays, and an exposure apparatus that is used for fabricating thin film magnetic heads, image capturing devices (CCDs), micromachines, MEMS, DNA chips, or reticles and masks.
Furthermore, in the embodiments discussed above, a light transmissive mask is used wherein a prescribed shielding pattern (or a phase pattern or a dimming pattern) is formed on a light transmissive substrate; however, instead of such a mask, it is also possible to use an electronic mask wherein a transmissive pattern, a reflective pattern, or a light emitting pattern is formed based on electronic data of the pattern to be exposed, as disclosed in, for example, U.S. Pat. No. 6,778,257; here, an electronic mask, which is also called a variable forming mask, includes, for example, a digital micromirror device (DMD), which is one type of a non-light emitting image display device (also called a spatial light modulator (SLM)). Furthermore, an exposure apparatus that uses a DMD is disclosed in, for example, U.S. Pat. No. 6,778,257.
In addition, by forming interference fringes on the substrate as disclosed in, for example, PCT International Publication WO2001/035168, the present invention can also be adapted to an exposure apparatus (i.e., a lithographic system) that exposes the substrate with a line-and-space pattern.
In addition, the present invention can also be adapted to, for example, an exposure apparatus that combines the patterns of two masks on a substrate through a projection optical system and double exposes, substantially simultaneously, a single shot region on the substrate using a single scanning exposure, as disclosed in, for example, Published Japanese Translation No. 2004-519850 of the PCT International Publication (corresponding 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.
As described above, the exposure apparatus 10 of the abovementioned embodiments is manufactured by assembling various subsystems, including each constituent element, such 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 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 from these various subsystems, there are also the processes of assembling each individual subsystem. When the process of assembling the exposure apparatus from the various subsystems is complete, a comprehensive adjustment is performed to ensure the various accuracies of the exposure apparatus as a whole. Furthermore, it is preferable to manufacture the exposure apparatus in a clean room wherein, for example, the temperature and the cleanliness level are controlled.
Next, a method of fabricating a liquid crystal display device using the exposure apparatus according to one embodiment of the present invention will be explained.
Subsequently, the exposed wafer W undergoes various processes, for example, a developing process, an etching process, and a stripping process, and thereby the prescribed pattern is formed on the wafer W, after which the method transitions to a succeeding color filter forming process S2. In the color filter forming process S2, a color filter is formed wherein numerous groups of three dots corresponding to R (red), G (green), and B (blue) are arrayed in a matrix, or a plurality of groups of filters, each filter comprising three stripes (R, G, and B), is arrayed in the horizontal scanning line directions. Furthermore, after the color filter forming process S2, a cell assembling process S3 is performed. In this cell assembling process S3, a liquid crystal panel (of liquid crystal cells) is assembled using, for example, the wafer W that has the prescribed pattern obtained in the pattern forming process S1 and the color filter obtained in the color filter forming process S2.
In the cell assembling process S3, the liquid crystal panel (of liquid crystal cells) is fabricated by, for example, injecting liquid crystal between the wafer W, which has the prescribed pattern obtained in the pattern forming process S1, and the color filter obtained in the color filter forming process S2. Subsequently, in a module assembling process S4, the liquid crystal display device is completed by attaching various components, such as a back light and an electrical circuit that operates the display of the assembled liquid crystal panel (of liquid crystal cells). The method of fabricating liquid c display devices discussed above can obtain liquid crystal display devices that have extremely fine patterns with good throughput.
The following text explains a method that adapts the exposure apparatus according to the embodiments of the present invention to an exposure apparatus that fabricates semiconductor devices and then uses such to fabricate semiconductor devices.
Next, in step S13 (i.e., a wafer processing step), the actual circuit and the like are formed on the wafer by, for example, lithographic technology (discussed later) using the mask and the wafer that were prepared in steps S10-S12. Then, in step S14 (i.e., a device assembling step), the device is assembled using the wafer that was processed in step S13. In step S14, processes are included as needed, such as the dicing, bonding, and packaging (i.e., chip encapsulating) processes. Lastly, in step S15 (i.e., an inspecting step), inspections are performed, for example, an operation verification test and a durability test of the microdevice fabricated in step S14. Finishing such processes completes the fabrication of the microdevice, which is then shipped.
In addition to fabricating microdevices such as liquid crystal display devices and semiconductor devices, the present invention can also be adapted to an exposure apparatus that transfers a pattern from a mother reticle to a glass substrate, a silicon wafer, or the like in order to fabricate a reticle or a mask to be used by a visible light exposure apparatus, an EUV exposure apparatus, an X-ray exposure apparatus, an electron beam exposure apparatus, and the like. Here, a transmissive reticle is generally used in an exposure apparatus that uses deep ultraviolet (DUV) light, vacuum ultraviolet (VUV) light, and the like; in addition, quartz glass, quartz glass doped with fluorine, fluorite, magnesium fluoride, quartz, and the like are used for the reticle substrate. In addition, a transmissive mask (i.e., a stencil mask or a membrane mask) is used with a proximity type X-ray exposure apparatus, an electron beam exposure apparatus, or the like, and a silicon wafer or the like is used for the mask substrate. Furthermore, such an exposure apparatus is disclosed in PCT International Publication No. WO99/34255, PCT International Publication No. WO99/50712, PCT International Publication No. WO99/66370, Japanese Unexamined Patent Application Publication No. H11-194479, Japanese Unexamined Patent Application Publication No. 2000-12453, Japanese Unexamined Patent Application Publication No. 2000-29202, and the like.
As far as permitted, each disclosure of every Patent documents and U.S. patent related to the exposure apparatus recited in each of the abovementioned embodiments, modified examples, and the like is hereby incorporated by reference in its entirety.
Number | Date | Country | Kind |
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2006-351479 | Dec 2006 | JP | national |
This is a Continuation Application of International Application No. PCT/JP2007/074673, filed Dec. 21, 2007, which claims priority to Japanese Patent Application No. 2006-351479, filed Dec. 27, 2006. The contents of the aforementioned applications are incorporated herein by reference.
Number | Date | Country | |
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Parent | PCT/JP2007/074673 | Dec 2007 | US |
Child | 12457914 | US |