Patent Application
20110102762
1. Field of the Invention
The present invention relates to exposure apparatuses and device manufacturing methods, and more particularly to an exposure apparatus that exposes an object with an energy beam via an optical system, and a device manufacturing method that uses the exposure apparatus.
2. Description of the Background Art
Conventionally, in a lithography process for manufacturing electron devices (microdevices) such as semiconductor devices (integrated circuits or the like) or liquid crystal display elements, an exposure apparatus such as a projection exposure apparatus by a step-and-repeat method (a so-called stepper), or a projection exposure apparatus by a step-and-scan method (a so-called scanning stepper (which is also called a scanner)) is mainly used.
A substrate such as a wafer or a glass plate that is subject to exposure used in this type of the exposure apparatus has been gradually (e.g. every ten years in the case of the wafer) grown in size. While a 300 mm-wafer with a diameter of 300 mm currently becomes mainstream, the coming of age of the 450 mm-wafer with a diameter of 450 mm looms near. When the size of the wafer shifts to 450 mm, the number of dies (chips) obtained from one wafer is twice or more of that of the current 300 mm-wafer, which contributes to the cost reduction.
Meanwhile, when the size of the wafer becomes as large as 450 mm, as the number of dies (chips) obtained from one wafer is increased, the time required for exposure processing of one wafer is increased, which decrease the throughput. Therefore, as a method to suppress the decrease in throughput as much as possible, employment of a twin-stage method (e.g. refer to U.S. Pat. No. 6,590,634, U.S. Pat. No. 5,969,441, U.S. Pat. No. 6,208,407 and the like) can be considered in which the exposure processing with respect to a wafer on one wafer stage and processing such as wafer exchange and alignment on another wafer stage are performed in parallel.
However, a wafer stage to cope with the 450 mm-wafer grows in size and the footprint of an apparatus increase in size. Especially, in the twin stage method, the footprint further increases. In addition, the movable range of the wafer stage that has grown in size becomes larger compared with the conventional one, and therefore, there was a risk that movement of the wafer stage is blocked by a tensile force of a tube that extracts/contracts in accordance with the movement of the wafer stage and is used to supply the power usage to the wafer stage. Further, a space needs to be secured in a lateral direction of a stage device in order not to inhibit deformation of the tube, and accordingly there was a risk that the throughput is further decreased.
According to a first aspect of the present invention, there is provided an exposure apparatus that exposes an object by irradiating the object with an energy beam, the apparatus comprising: a movable body, which holds the object, to which one end of a power usage transmitting member is connected, and which is movable along a first plane parallel to a predetermined two-dimensional plane that includes a first axis and a second axis orthogonal to each other, the power usage transmitting member having flexibility that forms a transmission path used when a power usage for the exposure is transmitted between the movable body and a predetermined external device; and an auxiliary movable body, which is placed on one side in a direction parallel to the first axis with respect to the movable body, to which the other end of the power usage transmitting member is connected, and which moves along a second plane parallel to the two-dimensional plane according to movement of the movable body and moves to the other side in the direction parallel to the first axis when the movable body moves to the one side in the direction parallel to the first axis.
With this apparatus, when the movable body that holds an object moves to one side of a direction parallel to the first axis, the auxiliary movable body used to transmit the power usage for exposure to the movable body via the power usage transmitting member moves to the other side of the direction parallel to the first axis. Therefore, the movable body is hardly affected by the drag (tensile force) by the power usage transmitting member, and also the protrusion of the power usage transmitting member in the direction parallel to the first axis is restrained.
According to a second aspect of the present invention, there is provided a device manufacturing method, comprising: exposing an object using the exposure apparatus of the present invention; and developing the object that has been exposed.
In the accompanying drawings;
An embodiment of the present invention is described below, with reference to
As shown in
Exposure station 200 is equipped with an illuminations system 10, a reticle stage RST, a projection unit PU, and the like.
Illumination system 10 includes: a light source; and an illumination optical system that has an illuminance uniformity optical system including an optical integrator and the like, and a reticle blind and the like (none of which are illustrated), as disclosed in, for example, U.S. Patent Application Publication No. 2003/0025890 and the like. Illumination system 10 illuminates a slit-shaped illumination area IAR, which is defined by the reticle blind (which is also referred to as a masking system), on reticle R with illumination light (exposure light) IL with substantially uniform illuminance. As illumination light IL, ArF excimer laser light (wavelength: 193 nm) is used as an example.
On reticle stage RST, reticle R having a pattern surface (the lower surface in
Positional information within the XY plane (including rotational information in the θz direction) of reticle stage RST is constantly detected at a resolution of, for example, around 0.25 nm with a reticle laser interferometer (hereinafter, referred to as a “reticle interferometer”) 13 via a movable mirror 15 fixed to reticle stage RST (actually, a Y movable mirror (or a retroreflector) that has a reflection surface orthogonal to the Y-axis direction and an X movable mirror that has a reflection surface orthogonal to the X-axis direction are arranged). The measurement values of reticle interferometer 13 are sent to a main controller 20 (not illustrated in
Above reticle stage RST, a pair of reticle alignment systems RA1 and RA2 by an image processing method, each of which has an imaging device such as a CCD and uses light with an exposure wavelength (illumination light IL in the embodiment) as alignment illumination light, are placed (in
Projection unit PU is placed below reticle stage RST in
Measurement station 300 is equipped with an alignment device 99 arranged at main frame BD. Alignment device 99 includes five alignment systems AL1 and AL21 to AL24 shown in
In the embodiment, as each of alignment systems AL1 and AL21 to AL24, for example, an FIA (Field Image Alignment) system by an image processing method is used. The configurations of alignment systems AL1 and AL21 to AL24 are disclosed in detail in, for example, PCT International. Publication No. 2008/056735 and the like. The imaging signal from each of alignment systems AL1 and AL21 to AL24 is supplied to main controller 20 (see
As shown in
Base board 12 is made up of a member having a tabular outer shape, and as shown in
As shown in
As shown in
Surface plates 14A and 14B respectively have first sections 14A1 and 14B1 each having a relatively thin plate shape on the upper surface of which the guide surface is formed, and second sections 14A2 and 14B2 each having a relatively thick plate shape and being short in the X-axis direction that are integrally fixed to the lower surfaces of first sections 14A1 and 14B1, respectively. The end on the +X side of first section 14A1 of surface plate 14A slightly overhangs, to the +X side, the end surface on the +X side of second section 14A2, and the end on the −X side of first section 14B1 of surface plate 14B slightly overhangs, to the −X side, the end surface on the −X side of second section 14B2.
Inside each of first sections 14A1 and 14B1, a coil unit (the illustration is omitted) is housed that includes a plurality of coils placed in a matrix shape with the XY two-dimensional directions serving as a row direction and a column direction. The magnitude and the direction of the electric current supplied to each of the plurality of coils that configure each of the coil units are controlled by main controller 20 (see
Inside (on the bottom portion of) second section 14A2 of surface plate 14A, a magnet unit (the illustration is omitted), which is made up of a plurality of permanent magnets (and yokes that are not illustrated) placed in a matrix shape with the XY two-dimensional directions serving as a row direction and a column direction, is housed so as to correspond to the coil unit housed on the upper surface side of base board 12. The magnet unit configures, together with the coil unit of base board 12, a surface plate driving system 60A (see
Similarly, inside (on the bottom portion of) second section 14B2 of surface plate 14B, a magnet unit (the illustration is omitted) made up of a plurality of permanent magnets (and yokes that are not illustrated) is housed that configures, together with the coil unit of base board 12, a surface plate driving system 60B (see
Positional information of surface plates 14A and 14B in the directions of three degrees of freedom is measured independently from each other by a first surface plate position measuring system 69A and a second surface plate position measuring system 69B (see
While the configurations of first surface plate position measuring system 69A and second surface plate position measuring system 69B are not especially limited, an encoder system can be used in which, for example, encoder heads, which measure positional information of the respective surface plates 14A and 14B in the directions of three degrees of freedom within the XY plane by irradiating measurement beams on scales (e.g. two-dimensional gratings) placed on the lower surfaces of second sections 14A2 and 14B2 respectively and using reflected light (diffraction light from the two-dimensional gratings) obtained by the irradiation, are placed at base board 12 (or the encoder heads are placed at second sections 14A2 and 14B2 and scales are placed at base board 12, respectively). Incidentally, it is also possible to measure the positional information of surface plates 14A and 14B by, for example, an optical interferometer system or a measurement system that is a combination of an optical interferometer system and an encoder system.
One of the wafer stages, wafer stage WST1 is equipped with fine movement stage WFS1 that holds wafer W and a coarse movement stage WCS1 having a rectangular frame shape that encloses the periphery of fine movement stage WFS1, as shown in
As shown in
Inside (on the bottom portions of) coarse movement slider sections 90a and 90b, as shown in
Incidentally, while coarse movement stages WCS1 and WCS2 of the embodiment have the configuration in which only coarse movement slider sections 90a and 90b have the magnet units of the planar motors, this is not intended to be limiting, and the magnet unit can be placed also at coupling members 92a and 92b. Further, the actuators to drive coarse movement stages WCS1 and WCS2 are not limited to the planar motors by the electromagnetic force (Lorentz force) drive method, but for example, planar motors by a variable magnetoresistance drive method or the like can be used. Further, the drive directions of coarse movement stages WCS1 and WCS2 are not limited to the directions of six degrees of freedom, but can be, for example, only directions of three degrees of freedom (X, Y, θz) within the XY plane. In this case, coarse movement stages WCS1 and WCS2 should be levitated above surface plates 14A and 14B, for example, using static gas bearings (e.g. air bearings). Further, in the embodiment, while the planar motor of a moving magnet type is used as each of coarse movement stage driving systems 62A and 62B, this is not intended to be limiting, and a planar motor of a moving coil type in which the magnet unit is placed at the surface plate and the coil unit is placed at the coarse movement stage can also be used.
On the side surface on the −Y side of coarse movement slider section 90a and on the side surface on the +Y side of coarse movement slider section 90b, guide members 94a and 94b that function as a guide used when fine movement stage WFS1 is finely driven are respectively fixed. As shown in
Inside (on the bottom surface of) guide member 94a, a pair of coil units CUa and CUb, each of which includes a plurality of coils placed in a matrix shape with the XY two-dimensional directions serving as a row direction and a column direction, are housed at a predetermined distance in the X-axis direction (see
Coupling member 92a is formed to be hollow, and piping members, wiring members and the like, which are not illustrated, used to supply the power usage to fine movement stage WFS1 are housed inside. Inside coupling members 92a and/or 92b, various types of optical members (e.g. an aerial image measuring instrument, an uneven illuminance measuring instrument, an illuminance monitor, a wavefront aberration measuring instrument, and the like) can be housed.
In this case, when wafer stage WST1 is driven with acceleration/deceleration in the Y-axis direction on surface plate 14A, by the planar motor that configures coarse movement stage driving system 62A (e.g. when wafer stage WST1 moves between exposure station 200 and measurement station 300), surface plate 14A is driven in a direction opposite to wafer stage WST1 according to the so-called law of action and reaction (the law of conservation of momentum) owing to the action of a reaction force by the drive of wafer stage WST1, in the case where surface plate driving system 60A described previously does not generate the drive force in the Y-axis direction.
Further, when wafer stage WST 2 is driven in the Y-axis direction on surface plate 14B, surface plate 14B is also driven in a direction opposite to wafer stage WST2 according to the so-called law of action and reaction (the law of conservation of momentum) owing to the action of a reaction force of a drive force of wafer stage WST2, in the case where surface plate driving system 60B described previously does not generate the drive force in the Y-axis direction. More specifically, surface plates 14A and 14B function as the countermasses and the momentum of a system composed of wafer stages WST1 and WST2 and surface plates 14A and 14B as a whole is conserved and movement of the center of gravity does not occur. Consequently, any inconveniences do not arise such as the uneven loading acting on surface plates 14A and 14B owing to the movement of wafer stages WST1 and WST2 in the Y-axis direction.
Further, by the action of a reaction force of a drive force in the X-axis direction of wafer stages WST1 and WST2, surface plates 14A and 14B function as the countermasses.
As shown in
Main section 80 is formed by a material with a relatively small coefficient of thermal expansion, e.g., ceramics, glass or the like, and is supported by coarse movement stage WCS1 in a noncontact manner in a state where the bottom surface of the main section is located flush with the bottom surface of coarse movement stage WCS1. Main section 80 can be hollowed for reduction in weight.
In the center of the upper surface of main section 80, a wafer holder (not illustrated) that holds wafer W by vacuum adsorption or the like is placed. In the embodiment, the wafer holder by a so-called pin chuck method is used in which a plurality of support sections (pin members) that support wafer W are formed, for example, within an annular protruding section (rim section), and the wafer holder, whose one surface (front surface) serves as a wafer mounting surface, has a two-dimensional grating RG to be described later and the like arranged on the other surface (back surface) side. Incidentally, the wafer holder can be formed integrally with fine movement stage WFS1 (main section 80), or can be fixed to main section 80 so as to be detachable via, for example, a holding mechanism such as an electrostatic chuck mechanism, a clamp mechanism or the like. In this case, grating RG should be arranged on the back surface side of main section 80. Further, the wafer holder can be fixed to main section 80 by an adhesive agent or the like.
Further, in the vicinity of a corner on the +X side located on the +Y side of main section 80, a measurement plate FM1 is placed substantially flush with the surface of wafer W. On the upper surface of measurement plate FM1, the pair of first fiducial marks to be respectively detected by the pair of reticle alignment systems RA1 and RA2 (see
In the center portion of the lower surface of main section 80 of fine movement stage WFS1, as shown in
As shown in
The pair of fine movement slider sections 84a and 84b are each supported by guide member 94a described earlier, and fine movement slider section 84c is supported by guide member 94b. More specifically, fine movement stage WFS1 (WFS2) is supported at three noncollinear positions with respect to coarse movement stage WCS1 (WCS2).
Inside fine movement slider sections 84a to 84c, magnet units 98a, 98b and 98c, which are each made up of a plurality of permanent magnets (and yokes that are not illustrated) placed in a matrix shape with the XY two-dimensional directions serving as a row direction and a column direction, are housed, respectively, so as to correspond to coil units CUa to CUc that guide members 94a and 94b of coarse movement stage WCS1 have. Magnet unit 98a together with coil unit CUa, magnet unit 98b together with coil unit CUb, and magnet unit 98c together with coil unit CUc respectively configure three planar motors by the electromagnetic force (Lorentz force) drive method that are capable of generating drive forces in the X-axis, Y-axis and Z-axis directions, as disclosed in, for example, U.S. Patent Application Publication No. 2003/0085676 and the like, and these three planar motors configure a fine movement stage driving system 64A (see
In wafer stage WST2 as well, three planar motors composed of coil units that coarse movement stage WCS2 has and magnet units that fine movement stage WFS2 has are configured likewise, and these three planar motors configure a fine movement stage driving system 64B (see
Fine movement stage WFS1 is movable in the X-axis direction, with a longer stroke compared with the directions of the other five degrees of freedom, along guide members 94a and 94b arranged extending in the X-axis direction. The same applies to fine movement stage WFS2.
In the embodiment, when broadly driving coarse movement stage WCS1 (or WCS2) with acceleration/deceleration in the X-axis direction (e.g. in the cases such as when a stepping operation between shot areas is performed during exposure), main controller 20 drives coarse movement stage WCS1 (or WCS2) in the X-axis direction by the planar motors that configure coarse movement stage driving system 62A (or 62B), and along with this drive, main controller 20 gives the initial velocity, which drives fine movement stage WFS1 (or WFS2) in the same direction as with coarse movement stage WCS1 (or WCS2), to fine movement stage WFS1 (or WFS2), via fine movement stage driving system 64A (or 64B) (drives fine movement stage WFS1 (or WFS2) in the same direction as with coarse movement stage WCS1 (or WCS2)). Accordingly, fine movement stage WFS1 (or WFS2) can be made to function as the so-called countermass, which make it possible, as a consequence, to decrease a movement distance of fine movement stage WFS1 (or WFS2) in the opposite direction that accompanies the movement of coarse movement stage WCS1 (or WCS2) in the X-axis direction (that is caused by a reaction force of the drive force). Especially, in the case where coarse movement stage WCS1 (or WCS2) performs an operation including the step movement in the X-axis direction, or more specifically, coarse movement stage WCS1 (or WCS2) performs an operation of alternately repeating the acceleration and the deceleration in the X-axis direction, the stroke in the X-axis direction needed for the movement of fine movement stage WFS1 (or WFS2) can be the shortest. On this operation, main controller 20 should give fine movement stage WFS1 (or WFS2) the initial velocity with which the center of gravity of the entire system of wafer stage WST1 (or WST2) that includes the fine movement stage and the coarse movement stage performs constant velocity motion in the X-axis direction. With this operation, fine movement stage WFS1 (or WFS2) performs a reciprocal motion within a predetermined range with the position of coarse movement stage WCS1 (or WCS2) serving as a reference. Consequently, as the movement stroke of fine movement stage WFS1 (or WFS2) in the X-axis direction, the distance that is obtained by adding some margin to the predetermined range should be prepared. Such details are disclosed in, for example, U.S. Patent Application Publication No. 2008/0143994 and the like.
Further, as described earlier, since fine movement stage WFS1 is supported at the three noncollinear positions by coarse movement stage WCS1, main controller 20 can tilt fine movement stage WFS1 (i.e. wafer W) at an arbitrary angle (rotational amount) in the θx direction and/or the θy direction with respect to the XY plane by, for example, appropriately controlling a drive force (thrust) in the Z-axis direction that is made to act on each of fine movement slider sections 84a to 84c. Further, main controller 20 can make the center portion of fine movement stage WFS1 bend in the +Z direction (into a convex shape), for example, by making a drive force in the +θx direction (a counterclockwise direction on the page surface of
Incidentally, in the embodiment, as fine movement stage driving systems 64A and 64B, the planar motors of a moving magnet type are used, but this is not intended to be limiting, and planar motors of a moving coil type in which the coil units are placed at the fine movement slider sections of the fine movement stages and the magnet units are placed at the guide members of the coarse movement stages can also be used.
Between coupling member 92a of coarse movement stage WCS1 and main section 80 of fine movement stage WFS1, as shown in
For example as shown in
Flat tubes Ta2 and Tb2 and flat tubes Ta1 and Tb1 (including piping/wiring members inside) that are described later can be bent and twisted as is described later.
As shown in
One ends and the other ends of the pair of flat tubes Tb2 are connected to the side surface of wafer stage WST2 (coupling member 92a) and the pair of flat tubes Tb1 via a tube carrier TCb1 that configures a part of tube carrier device TCb placed on the +X side of base board 12. Incidentally, a configuration can also be employed in which a pair of flat tubes are each divided, and either of the divided tubes serving as flat tubes Ta1 and Tb1 are connected to tube carriers TCa1 and TCb1 and the other of the divided tubes serving as flat tubes Ta2 and Tb2 are connected to tube carriers TCa1 and TCb1.
Flat tubes Ta1 and Tb1 are connected to various types of power usage sources (not illustrated), e.g. an electric power supply, a gas tank, a compressor, a vacuum pump or the like, along the −X end and the +X end of base board 12, respectively, or through the inside of base board 12. The power usage is supplied from the power usage sources (not illustrated) to fine movement stage WFS1 sequentially via the pair of flat tubes Ta1, tube carrier TCa1, the pair of flat tubes Ta2, coupling member 92a of coarse movement stage WCS1 and the pair of tubes 86a and 86b. Similarly, the power usage is supplied from the power usage sources (not illustrated) to fine movement stage WFS2 sequentially via the pair of flat tubes Tb1, tube carrier TCb1, the pair of flat tubes Tb2, coupling member 92a of coarse movement stage WCS2 and the pair of tubes 86a and 86b.
As shown in
As shown in
As shown in
As shown in
Support sections TCa3 and TCa4 are each made up of a member with the X-axis direction serving as its longitudinal direction, and are placed on the floor surface (see
Tube carrier TCa1 and X slider TCa2 that configure tube carrier device TCa are respectively driven by a first drive device TDa1 and a second drive device TDa2 (see
As shown in
As shown in
Positional information of tube carrier TCa1 in the Y-axis direction with respect to X slider TCa2 and positional information of the ±Y ends of X slider TCa2 in the X-axis direction with respect to each of support sections TCa3 and TCa4 are measured by a first measurement section TEa1 and a second measurement section TEa2 (see
As shown in
Meanwhile, as shown in
The measurement results of tube carrier position measuring system TEA (first and second measurement sections TEa1 and TEa2) are transmitted to main controller 20 (see
Next, an example of the follow-up drive of tube carrier TCa1 with respect to wafer stage WST1 that is performed in the present embodiment is described, with reference to
When main controller 20 drives wafer stage WST1 in the Y-axis direction, e.g. the −Y direction, main controller 20 controls first drive device TDa1 (see
Furthermore, when main controller 20 drives wafer stage WST1 in the X-axis direction, e.g. the −X direction as indicated by a black arrow in
As described above, in stage device 50 (see
Meanwhile, regarding flat tube Ta1, X slider TCa2 (tube carrier TCa1 supported by X slider TCa2) is driven, for example, in the +X direction, and thereby a pair of opposed surfaces, which are opposed to each other, of the bent section having a roughly U-like shape in a planar view approach, as shown in
In this case, in tube carrier device TCa of the present embodiment, as shown in
Meanwhile, regarding flat tube Ta1, X slider TCa2 (tube carrier TCa1 supported by X slider TCa2) is driven in the −X direction, and thereby a pair of opposed surfaces, which are opposed to each other, of the bent section having a roughly U-like shape move away from each other, as shown in
In the present embodiment, as described above, by driving and controlling tube carrier device TCa according to the movement of wafer stage WST1, it becomes possible to drive and control wafer stage WST1 without undergoing a tensile force (drag) from flat tubes Ta1 and Ta2 and further without widening a space where flat tubes Ta1 and Ta2 occupy within exposure apparatus 100.
Similarly to tube carrier device TCa described above, another tube carrier, tube carrier device TCb is also configured of tube carrier TCb1 that moves in the Y-axis direction while holding flat tubes Tb1 and Tb2, an X slider TCb2 that moves in the X-axis direction while supporting tube carrier TCb1, and a pair of support section TCb3 and TCb4 that support both ends of X slider TCb2. Tube carrier TCb1 and X slider TCb2 are driven by a tube carrier driving system TDB (see
The measurement results of tube carrier position measuring system TEB are transmitted to main controller 20 (see
Next, a measurement system that measures positional information of wafer stages WST1 and WST2 is described. Exposure apparatus 100 has a fine movement stage position measuring system 70 (see
Fine movement stage position measuring system 70 has a measurement bar 71 shown in
At measurement bar 71, as shown in
As shown in
X head 75x, Y heads 75ya and 75yb and the three Z heads 76a to 76c are placed in a state where their positions do not vary, inside measurement bar 71. X head 75x is placed on reference axis LV, and Y heads 75ya and 75yb are placed at the same distance apart from X head 75x, on the −X side and the +X side, respectively. In the embodiment, as each of the three encoder heads 75x, 75ya and 75yb, a diffraction interference type head having a configuration in which a light source, a photodetection system (including a photodetector) and various types of optical systems are unitized is used, which is similar to the encoder head disclosed in, for example, U.S. Patent Application Publication No. 2007/0288121 and the like.
When wafer stage WST1 (or WST2) is located directly under projection optical system PL (see
In this case, an irradiation point (detection point), on grating RG, of the measurement beam emitted from X head 75x coincides with the exposure position that is the center of exposure area IA (see
As each of Z heads 76a to 76c, for example, a head of a displacement sensor by an optical method similar to an optical pickup used in a CD drive device or the like is used. The three Z heads 76a to 76c are placed at the positions corresponding to the respective vertices of an isosceles triangle (or an equilateral triangle). Z heads 76a to 76c configure a surface position measuring system 54 (see
Further, the center of gravity of the isosceles triangle (or the equilateral triangle) whose vertices are at the three irradiation points on grating RG of the measurement beams respectively emitted from the three Z heads 76a to 76c coincides with the exposure position that is the center of exposure area IA (see
Second measurement head group 73 has an X head 77x that configures an X liner encoder 55 (see
Incidentally, while each of X heads 75x and 77x and Y heads 75ya, 75yb, 77ya and 77yb of the embodiment has the light source, the photodetection system (including the photodetector) and the various types of optical systems (none of which are illustrated) that are unitized and placed inside measurement bar 71, the configuration of the encoder head is not limited thereto, and for example, the light source and the photodetection system can be placed outside the measurement bar. In such a case, the optical systems placed inside the measurement bar, and the light source and the photodetection system are connected to each other via, for example, an optical fiber or the like. Further, a configuration can also be employed in which the encoder head is placed outside the measurement bar and only a measurement beam is guided to the grating via an optical fiber placed inside the measurement bar. Further, the rotational information of the wafer in the θz direction can be measured using a pair of the X liner encoders (in this case, there should be one Y linear encoder). Further, the surface position information of the fine movement stage can be measured using, for example, an optical interferometer. Further, instead of the respective heads of first measurement head group 72 and second measurement head group 73, three encoder heads in total, which include at least one XZ encoder head whose measurement directions are the X-axis direction and the Z-axis direction and at least one YZ encoder head whose measurement directions are the Y-axis direction and the Z-axis direction, can be arranged in the placement similar to that of the X head and the pair of Y heads described earlier.
When wafer stage WST1 moves between exposure station 200 and measurement station 300 on surface plate 14A, coarse movement stage position measuring system 68A (see
A coarse movement stage position measuring system 68B (see
Further, exposure apparatus 100 is also equipped with a relative position measuring system 66A and a relative position measuring system 66B (see
In exposure apparatus 100 configured as described above, exposure on wafers in a predetermined number of lots or on a predetermined number of wafers is performed by alternately using wafer stages WST1 and WST2. More specifically, in parallel with performing the exposure operation on a wafer held by one of wafer stages WST1 and WST2, main controller 20 performs wafer exchange and at least a part of wafer alignment on the other of wafer stages WST1 and WST2, and thereby the parallel processing operation described above is performed using wafer stages WST1 and WST2 alternately, in a manner similar to a typical exposure apparatus of a twin-wafer-stage type. In exposure apparatus 100, the operation similar to the typical exposure apparatus of a twin-wafer-stage type is performed, and accordingly the detailed description is omitted herein.
However, in exposure apparatus 100, on the parallel processing operation described above, when driving wafer stages WST1 and WST2 in the X-axis direction and the Y-axis direction, main controller 20 drives tube carriers TCa1 and TCb1 via tube carrier driving systems TDA and TDB as described previously, in response to the movement of the wafer stages. In this case, wafer stage WST1 moves in the X-axis direction between a position, with which the center of wafer stage WST1 is located on the +X side of reference axis LV, and the −X end on surface plate 14A. And, wafer stage WST2 moves in the X-axis direction between a position, with which the center of wafer stage WST2 is located on the −X side of reference axis LV, and the +X end on surface plate 14B. However, when wafer stage WST1 (WST2) is driven in the X-axis direction by main controller 20, tube carrier TCa1 (TCb1) is driven in a direction opposite to the wafer stage by the same distance as the drive distance of the wafer stage, and therefore, when wafer stage WST1 (WST2) broadly moves in the X-axis direction, a tensile force acting on flat tubes Ta1 and Ta2 (Tb1 and Tb2) are substantially constant, and the protruding amount of flat tube Ta2 (Tb2) that protrudes outside in the X-axis direction is also substantially constant. More specifically, a U-like shape bending section having a constant curvature is constantly formed at flat tube Ta1 (Tb2).
As described in detail above, in exposure apparatus 100 of the embodiment, tube carrier device TCa (TCb) is arranged which has tube carrier TCa1 (TCb1) to move in the Y-axis direction while holding flat tube Ta1 (Ta2) that supplies the power usage to wafer stage WST1 (WST2), X slider TCa2 (TCb2) to move in the X-axis direction while supporting tube carrier TCa1 (TCb1), the pair of support sections TCa3 and TCa4 (TCb3 and TCb4) to support the both ends of X slider TCa2 (TCb2). And, main controller 20 drives tube carrier TCa1 (TCb1) in the Y-axis direction according to the movement of wafer stage WST1 (WST2) in the Y-axis direction, and drives tube carrier TCa1 (TCb1) integrally with slider TCa2 (TCb2) in the relative direction (opposite direction) according to the movement of wafer stage WST1 (WST2) in the X-axis direction. Therefore, wafer stage WST1 (WST2) is hardly receive the drag (tensile force) from flat tube Ta1 and Ta2 (Tb1 and Tb2), which makes it possible to drive wafer stage WST1 (WST2) with high accuracy. Further, on the movement of wafer stage WST1 (WST2) in the X-axis direction that is the direction of movement of tube carrier TCa1 (TCb1) with a short stroke, flat tube Ta1 and Ta2 (Tb1 and Tb2) do not protrude outside.
Further, according to exposure apparatus 100 of the embodiment, at least a part of encoder heads 75x, 75ya and 75yb, which irradiate the measurement surfaces, parallel to the XY plane, of fine movement stages WFS1 and WFS2 with measurement beams and receive the light from gratings RG placed on the measurement surfaces, is placed at measurement bar 71 placed on the side opposite to projection optical system PL (−Z side) with respect to the guide surface (the upper surfaces of surface plates 14A and 14B) used on the movement of fine movement stages WFS1 and WFS2 (wafer stages WST1 and WST2) Further, during the exposure operation and during the wafer alignment (mainly, during the measurement of the alignment marks), first measurement head group 72 and second measurement head group 73 fixed to measurement bar 71 are respectively used in the measurement of the positional information (the positional information within the XY plane and the surface position information) of fine movement stage WFS1 (or WFS2) that holds wafer W. And, since the encoder heads 75x, 75ya and 75yb and Z heads 76a to 76c that configure first measurement head group 72, and encoder heads 77x, 77ya and 77yb and Z heads 78a to 78c that configure second measurement head group 73 can respectively irradiate grating RG placed on the bottom surface of fine movement stage WFS1 (or WFS2) with measurement beams from directly below at the shortest distance. Therefore, the measurement error of encoder heads 75x, 75ya, 75yb and the like caused by the temperature fluctuation of the surrounding atmosphere of wafer stages WST1 and WST2, e.g. air fluctuation, becomes small, which makes it possible to perform high-precision measurement of the positional information of fine movement stages WFS1 and WFS2. Consequently, even if fine movement stages WFS1 and WFS2 grow in size, the positional information of fine movement stages WFS1 and WFS2 is measured with high precision by fine movement stage position measuring system 70, and based on the measurement information, i.e., the positional information of fine movement stages WFS1 and WFS2 measured with high precision, main controller 20 measures the positions of fine movement stages WFS1 and WFS2 with high precision.
Further, first measurement head group 72 measures the positional information within the XY plane and the surface position information of fine movement stage WFS1 (or WFS2) at the point that substantially coincides with the exposure position that is the center of exposure area IA on wafer W, and second measurement head group 73 measures the positional information within the XY plane and the surface position information of fine movement stage WFS1 (or WFS2) at the point that substantially coincides with the detection area of primary alignment system AL1. Consequently, occurrence of the so-called Abbe error caused by the positional error within the XY plane between the measurement point and the exposure position is restrained, and also in this regard, the high-precision measurement of the positional information of fine movement stage WFS1 or WFS2 becomes possible.
Incidentally, in the embodiment above, the case has been described where main controller 20 drives tube carrier TCa1 (TCb1) according to the movement of wafer stage WST1 (WST2), or more specifically, main controller 20 drives tube carrier TCa1 (TCb1) based on the measurement information of fine movement stage position measuring system 70, coarse movement stage position measuring system 68A (68B), and tube carrier position measuring system TEA (TEB). However, since the required accuracy for position control of the tube carriers is lower compared with that of the wafer stages, it is also possible to make the tube carriers move in conjunction with the movement of wafer stage WST1 (WST2) by, for example, control of the electric current value or the like, without performing the measurement of the positional information.
Incidentally, in place of tube carrier devices TCa and TCb in the embodiment above, a configuration can also employed in which tube carriers TCa1 and TCb1 move in the XY direction on surface plates 14A and 14B or base board 12 while holding flat tubes Ta1 and Ta2 (Tb1 and Tb2). In this case, movers are arranged at the bottom sections of tube carriers TCa1 and TCb1, and planer motors (such as planar motors by the electromagnetic force (Lorentz force) drive method or the variable magnetoresistance drive method) that are configured of such movers and stators arranged in surface plates 14A and 14B or base board 12 can be employed as drive devices of tube carriers TCa1 and TCb1.
Further, in the embodiment above, the configuration is employed in which the positional information of tube carrier devices TCa and TCb, i.e. the positional information of tube carriers TCa1 and TCb1 with respect to X sliders TCa2 and TCb2 in the Y-axis direction and the positional information of the ±Y ends of X sliders TCa2 and TCb2 with respect to support sections TCa3 and TCa4 and with respect to support sections TCb3 and TCb4 in the X-axis direction, respectively, are measured using the encoder (first measurement section TEa1 and second measurement section TEa2). In this case, it is also possible to employ, for example, an interferometer, instead of the encoder, as the position measuring instrument of tube carrier devices TCa and TCb.
Further, in the embodiment above, while in exposure apparatus 100 equipped with the two wafer stages WST1 and WST2, tube carrier devices TCa and TCb are respectively arranged at the two stages, it is also possible to arrange the tube carriers having the similar configuration in exposure apparatus 100 equipped with only one wafer stage or three or more wafer stages.
Incidentally, while the exposure apparatus of the embodiment above has the two surface plates that correspond to the two wafer stages, the number of the surface plates is not limited to two, and can be, for example, one. Further, a measurement stage, for example, which has an aerial image measuring instrument, an uneven illuminance measuring instrument, an illuminance monitor, a wavefront aberration measuring instrument and the like, can be placed on the surface plate, as disclosed in, for example, U.S. Patent Application Publication No. 2007/0201010.
Further, in the embodiment above, while both ends of measurement bar 71 in the longitudinal direction are supported in a suspended manner by main frame BD, this is not intended to be limiting, and for example, the mid portion (which can be arranged at a plurality of positions) in the longitudinal direction of the measurement bar can be supported on the base board by an empty-weight canceller as disclosed in, for example, U.S. Patent Application Publication No. 2007/0201010.
Further, the motor to drive surface plates 14A and 14B on base board 12 is not limited to the planar motor by the electromagnetic force (Lorentz force) drive method, but for example, can be a planar motor (or a linear motor) by a variable magnetoresistance drive method. Further, the motor is not limited to the planar motor, but can be a voice coil motor that includes a mover fixed to the side surface of the surface plate and a stator fixed to the base board. Further, the surface plates can be supported on the base board via the empty-weight canceller as disclosed in, for example, U.S. Patent Application Publication No. 2007/0201010 and the like. Further, the drive directions of the surface plates are not limited to the directions of six degrees of freedom, but for example, can be only the Y-axis direction, or only the XY two-axial directions. In this case, the surface plates can be levitated above the base board by static gas bearings (e.g. air bearings) or the like. Further, in the case where the movement direction of the surface plates can be only the Y-axis direction, the surface plates can be mounted on, for example, a Y guide member arranged extending in the Y-axis direction so as to be movable in the Y-axis direction.
Further, in the embodiment above, while the grating is placed on the lower surface of the fine movement stage, in other words, the surface that is opposed to the upper surface of the surface plate, this is not intended to be limiting, and the main section of the fine movement stage is made up of a solid member that can transmit light, and the grating can be placed on the upper surface of the main section. In this case, since the distance between the wafer and the grating is closer compared with the embodiment above, the Abbe error, which is caused by the difference in the Z-axis direction between the surface subject to exposure of the wafer that includes the exposure point and the reference surface (the placement surface of the grating) of position measurement of the fine movement stage by encoders 51, 52 and 53, can be reduced. Further, the grating can be formed on the back surface of the wafer holder. In this case, even if the wafer holder expands or the attachment position with respect to the fine movement stage shifts during exposure, the position of the wafer holder (wafer) can be measured according to the expansion or the shift.
Further, in the embodiment above, while the case has been described as an example where the encoder system is equipped with the Y head and the pair of X heads, this is not intended to be limiting, and for example, one or two two-dimensional head(s) (2D head(s)) whose measurement directions are the two directions that are the X-axis direction and the Y-axis direction can be placed inside the measurement bar. In the case of arranging the two 2D heads, their detection points can be set at the two points that are spaced apart in the X-axis direction at the same distance from the exposure position as the center, on the grating.
Further, in the embodiment above, the measurement beams emitted from the encoder heads and the measurement beams emitted from the Z heads are irradiated on the gratings of the fine movement stages via a gap between the two surface plates or the light-transmitting section formed at each of the surface plates. In this case, as the light-transmitting section, holes each of which is slightly larger than a beam diameter of each of the measurement beams are formed at each of surface plates 14A and 14B taking the movement range of surface plate 14A or 14B as the countermass into consideration, and the measurement beams can be made to pass through these multiple opening sections. Further, for example, it is also possible that pencil-type heads are used as the respective encoder heads and the respective Z heads, and opening sections in which these heads are inserted are formed at each of the surface plates.
Further, while the case has been described where the embodiment above is applied to the dry type exposure apparatus, the embodiment above can also be applied to a wet type (liquid immersion type) exposure apparatus that is disclosed in, for example, PCT International Publication No. 99/49504, U.S. Patent Application Publication No. 2005/0259234 and the like.
Incidentally, in the embodiment above, while the case has been described where the exposure apparatus is a scanning stepper, this is not intended to be limiting, and the exposure apparatus can be a static exposure apparatus such as a stepper. Even in the stepper or the like, occurrence of position measurement error caused by air fluctuation can be reduced to almost zero by measuring the position of a stage on which an object that is subject to exposure is mounted using an encoder, and therefore, the position of the stage can be set with high precision based on the measurement values of the encoder, and as a consequence, it becomes possible to perform high-precision transfer of a reticle pattern onto the object. Further, the embodiment above can also be applied to a reduced projection exposure apparatus by a step-and-stitch method that synthesizes a shot area and a shot area.
Further, the magnification of the projection optical system in the exposure apparatus of the embodiment above is not only a reduction system, but also can be either an equal magnifying system or a magnifying system, and the projection optical system is not only a dioptric system, but also can be either a catoptric system or a catadioptric system, and in addition, the projected image can be either an inverted image or an erected image.
Further, illumination light IL is not limited to ArF excimer laser light (with a wavelength of 193 nm), but can be ultraviolet light such as KrF excimer laser light (with a wavelength of 248 nm), or vacuum ultraviolet light such as F2 laser light (with a wavelength of 157 nm). As disclosed in, for example, U.S. Pat. No. 7,023,610, a harmonic wave, which is obtained by amplifying a single-wavelength laser beam in the infrared or visible range emitted by a DFB semiconductor laser or fiber laser with a fiber amplifier doped with, for example, erbium (or both erbium and ytteribium), and by converting the wavelength into ultraviolet light using a nonlinear optical crystal, can also be used as vacuum ultraviolet light.
Further, in the embodiment above, illumination light IL of the exposure apparatus is not limited to the light having a wavelength more than or equal to 100 nm, and it is needless to say that the light having a wavelength less than 100 nm can be used For example, the embodiment above can be applied to an EUV (Extreme Ultraviolet) exposure apparatus that uses EUV light in a soft X-ray range (e.g. a wavelength range from 5 to 15 nm). In addition, the embodiment above can also be applied to an exposure apparatus that uses charged particle beams such as an electron beam or an ion beam.
Further, in the embodiment above, a light transmissive type mask (reticle) is used, which is obtained by forming a predetermined light-shielding pattern (or a phase pattern or a light-attenuation pattern) on a light-transmitting substrate, but instead of this reticle, as disclosed in, for example, U.S. Pat. No. 6,778,257, an electron mask (which is also called a variable shaped mask, an active mask or an image generator, and includes, for example, a DMD (Digital Micromirror Device) that is a type of a non-emission type image display element (spatial light modulator) or the like) on which a light-transmitting pattern, a reflection pattern, or an emission pattern is formed according to electronic data of the pattern that is to be exposed can also be used. In the case of using such a variable shaped mask, a stage on which a wafer, a glass plate or the like is mounted is scanned relative to the variable shaped mask, and therefore the equivalent effect to the embodiment above can be obtained by measuring the position of this stage using an encoder system.
Further, the embodiment above can also be applied to an exposure apparatus (a lithography system) in which line-and-space patterns are formed on wafer W by forming interference fringes on wafer W, as disclosed in, for example, PCT International Publication No. 2001/035168.
Moreover, the embodiment above can also be applied to an exposure apparatus that synthesizes two reticle patterns on a wafer via a projection optical system and almost simultaneously performs double exposure of one shot area on the wafer by one scanning exposure, as disclosed in, for example, U.S. Pat. No. 6,611,316.
Incidentally, an object on which a pattern is to be formed (an object subject to exposure on which an energy beam is irradiated) in the embodiment above is not limited to a wafer, but may be another object such as a glass plate, a ceramic substrate, a film member, or a mask blank.
The application of the exposure apparatus is not limited to the exposure apparatus used for manufacturing semiconductor devices, but the embodiment above can be widely applied also to, for example, an exposure apparatus for manufacturing liquid crystal display elements in which a liquid crystal display element pattern is transferred onto a rectangular glass plate, and to an exposure apparatus for manufacturing organic EL, thin-film magnetic heads, imaging devices (such as CCDs), micromachines, DNA chips or the like. Further, the embodiment above can also be applied to an exposure apparatus that transfers a circuit pattern onto a glass substrate, a silicon wafer or the like not only when producing microdevices such as semiconductor devices, but also when producing a reticle or a mask used in an exposure apparatus such as an optical exposure apparatus, an EUV exposure apparatus, an X-ray exposure apparatus, and an electron beam exposure apparatus.
Incidentally, the disclosures of all publications, the PCT International Publications, the U.S. Patent Application Publications and the U.S. patents that are cited in the description so far related to exposure apparatuses and the like are each incorporated herein by reference.
Electron devices such as semiconductor devices are manufactured through the following steps: a step where the function/performance design of a device is performed; a step where a reticle based on the design step is manufactured; a step where a wafer is manufactured using a silicon material; a lithography step where a pattern of a mask (the reticle) is transferred onto the wafer with the exposure apparatus (pattern formation apparatus) of the embodiment described earlier and the exposure method thereof; a development step where the exposed wafer is developed; an etching step where an exposed member of an area other than an area where resist remains is removed by etching; a resist removing step where the resist that is no longer necessary when the etching is completed is removed; a device assembly step (including a dicing process, a bonding process, and a packaging process); an inspection step; and the like. In this case, in the lithography step, the exposure method described earlier is executed using the exposure apparatus of the embodiment above and device patterns are formed on the wafer, and therefore, the devices with high integration degree can be manufactured with high productivity.
While the above-described embodiment of the present invention is the presently preferred embodiment thereof, those skilled in the art of lithography systems will readily recognize that numerous additions, modifications, and substitutions may be made to the above-described embodiment without departing from the spirit and scope thereof. It is intended that all such modifications, additions, and substitutions fall within the scope of the present invention, which is best defined by the claims appended below.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2009-250128 | Oct 2009 | JP | national |
This non-provisional application claims the benefit of Provisional Application No. 61/272,898 filed Nov. 17, 2009, the disclosure of which is hereby incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 61272898 | Nov 2009 | US |
