Stage device, vacuum device, and charged particle beam device

Abstract

Provided is a stage device that suppresses vibration of a stator of a motor, and that enables high-speed positioning. The stage device comprises: a first table; a second table that is able to move within a horizontal plane in a state of magnetic levitation over the first table; a support section for supporting the second table; a first double-shaft motor provided to the support section; and a second double-shaft motor provided to the support section. The first double-shaft motor and second double-shaft motor each comprise: a yoke provided with an upper member and a lower member; and a first and a second rectangular coil which are located between the upper member and the lower member and are each fixed to the support section, and an axial direction of which is the vertical direction. On a lower surface of the upper member and an upper surface of the lower member, there are provided magnet arrays, in which magnets are arranged in square blocks arrayed in a grid so that adjacent blocks have different magnetic poles. The magnet array provided to the lower surface of the upper member and the magnet array provided to the upper surface of the lower member are configured so that magnets of blocks that face opposite in the vertical direction have different magnetic poles from one another.

Description

Stage device, vacuum device, and charged particle beam device

[0001] The present disclosure relates to a stage apparatus, a vacuum apparatus, and a charged particle beam apparatus.

[0002] A magnetic levitation stage device is known as a technology for positioning and supporting a semiconductor wafer. For example, Patent Document 1 describes a magnetic levitation stage device. Paragraph 0020 and FIG. 1(a) of Patent Document 1 disclose that "an actuator for moving the stage YM is disposed on the bottom surface of the stage YM. Magnet units XAM, YAM, and ZAM serve as movers of the actuator. ... The two magnet units YAM move the stage YM in the Y-axis direction. ... Each of the magnet units XAM, YAM, and ZAM has a hollow structure so that coils XAC, YAC, and ZAC, which are stators of the actuators corresponding to the magnet units XAM, YAM, and ZAM, can pass through." Furthermore, paragraph 0021 of Patent Document 1 discloses that "The magnet unit YAM has magnets YAMM arranged above and below the coil YAC, and each magnet YAMM is further sandwiched between yokes YAMY above and below. The yokes YAMY are further fixed to each other with intermediate members YAMI. Magnets YAMM with different magnetic poles are arranged alternately in the Y-axis direction." Furthermore, paragraph 0025 and Figure 2(a) of Patent Document 1 disclose that "The coil YAC is composed of a multi-phase coil, and is configured to allow the stage YM to move a long distance in the Y-axis direction."

[0003] JP 2015-198121 A

[0004] That is, in the magnetic levitation stage device of Patent Document 1, the magnet unit YAM has a hollow structure and moves a long distance in the Y-axis direction along the coil YAC that passes through the hollow part of the magnet unit YAM. Because the magnet unit YAM moves in this way, the coil YAC has a structure in which only both ends are fixed and the center part is not in contact with other objects.

[0005] In processes such as manufacturing, measuring, and inspecting semiconductor wafers, stage devices are required to be able to position semiconductor wafers at high speed and with high accuracy. However, in the magnetic levitation stage device of Patent Document 1, when the stroke in the Y-axis direction is long, the coil YAC, which is fixed only at both ends, vibrates, which causes the natural frequency of the stage device to be low, which places restrictions on improving the control band and makes high-speed positioning difficult.

[0006] An object of the present disclosure is to provide a stage device, a vacuum device, and a charged particle beam device that are capable of suppressing vibration of a motor stator and enabling high-speed positioning.

[0007] The stage device of the present disclosure is, for example, a stage device that positions a sample stage within a horizontal plane, and includes: a first table; a second table on which the sample stage is provided and which is movable within the horizontal plane while being magnetically levitated relative to the first table; a support portion that supports the second table; a first two-axis motor that is provided on the support portion; and a second two-axis motor that is provided on the support portion. The first two-axis motor and the second two-axis motor each include a yoke that includes an upper member and a lower member, and first and second rectangular coils that are located between the upper member and the lower member and are fixed to the support portion, respectively, and have an axial direction in the vertical direction. On the lower surface of the upper member and on the upper surface of the lower member, magnet arrays are provided, in which magnets are arranged in square compartments that are arranged in a grid pattern so that adjacent compartments have different magnetic poles, and the magnet array provided on the lower surface of the upper member and the magnet array provided on the upper surface of the lower member have magnets in compartments that face each other in the vertical direction that have different magnetic poles.

[0008] Furthermore, the vacuum apparatus of the present disclosure includes, for example, the stage apparatus and a vacuum chamber that houses the stage apparatus and is in a vacuum state inside.

[0009] The charged particle beam device disclosed herein also includes, for example, the stage device, a vacuum chamber that houses the stage device and has a vacuum state inside, and an electron optical system column that irradiates an electron beam onto a sample placed on the stage device.

[0010] According to the present disclosure, it is possible to provide a stage device, a vacuum device, and a charged particle beam device that are capable of suppressing vibration of a motor stator and enabling high-speed positioning. Other objects and novel features will become apparent from the description of this specification and the accompanying drawings.

[0011] 11A-11C are cross-sectional views of a stage device using rolling guides according to Comparative Example 1; FIG. 11B are cross-sectional views of a magnetically levitated stage device according to Comparative Example 2; FIG. 11C are cross-sectional views of an X-axis motor according to Comparative Example 2; FIG. 11D are cross-sectional views of a Y-axis motor according to Comparative Example 2; FIG. 11E are cross-sectional views of a Z-axis motor according to Comparative Example 2; FIG. 11F are cross-sectional views of an X-axis motor according to Comparative Example 2; FIG. 11G are cross-sectional views of a Y-axis motor according to Comparative Example 2; FIG. 11H are cross-sectional views of a Z-axis motor according to Comparative Example 2; FIG. 11H are cross-sectional views of an X-axis motor according to Comparative Example 2; FIG. 11H are cross-sectional views of a Y-axis motor according to Comparative Example 2; FIG. 11H are cross-sectional views of an Z-axis motor according to Comparative Example 2; FIG. 11H are cross-sectional views of an X ...

[0012] First, the problems with the conventional stage device will be explained using a comparative example.

[0013] Comparative Example 1 FIG. 1 is a diagram showing an example of the configuration of a stage device using rolling guides according to Comparative Example 1. The stage device shown in FIG. 1 has a stacked stage configuration using rolling guides on both the X-axis and Y-axis. A Y-table 109 is guided by a Y-axis guide 110, and an X-table 111 is guided by an X-axis guide 120. A top table 101, to which a sample 104 and a bar mirror 102 are fixed, is mounted on the X-table 111. The bar mirror 102 is used to measure the position of the sample 104 using a laser interferometer or the like. A yoke 506 of an X-axis linear motor is fixed on the Y-table 109, and a coil (not shown) of the X-axis linear motor is fixed to the X-table 111. As a result, a thrust in the X-axis direction is applied to the linear motor coil, and an X-axis thrust is applied to the X-table 111. Furthermore, a reaction force is generated in the yoke 506 in the direction opposite to the X-axis thrust applied to the linear motor coil. The stage device of Comparative Example 1 suffers from the problem of low positioning accuracy of the sample 104.

[0014] Comparative Example 2 FIG. 2 shows an example of the configuration of a magnetically levitated stage device of Comparative Example 2. In this comparative example, the top table 101 is magnetically levitated with respect to the Y table 109. A magnetically levitated stage device can improve positioning accuracy by using non-contact guides. However, the position and orientation of the top table 101 must be controlled with six degrees of freedom: displacement in the X, Y, and Z directions and rotation about the X, Y, and Z axes. Therefore, while the stage device of FIG. 1 , in which the top table 101 is not magnetically levitated, requires only one X-axis motor, the number of motor axes acting as driving elements increases to six. Specifically, while the X-axis guide 120 constrains displacement in the Y-axis and Z-axis directions in Comparative Example 1, the magnetically levitated stage device (Comparative Example 2) does not require the X-axis guide 120, and therefore requires Y-axis and Z-axis motors to constrain displacement in the Y-axis and Z-axis directions. 2, the yoke 504 of the X-axis motor is rod-shaped and is configured so that only both ends are fixed to the Y-table 109, making it prone to vibration. In this way, a magnetic levitation stage device with a long stroke in one direction requires many linear motor yokes, which are rod-shaped structures, and because some are fixed only at both ends, the natural frequency decreases, limiting the control band and making it difficult to increase speed. Other issues include reduced ease of assembly and maintenance.

[0015] 3 shows an example of the configuration of an X-axis motor. Magnetic flux 108 is formed by permanent magnet 105 and U-shaped yoke 504. The direction 113 of current flowing through coil 107 generates a Lorentz force, generating an X-axis thrust 112X. A three-phase AC linear motor may be used to generate a stroke of several hundred mm in the X-axis direction.

[0016] 4 shows an example of the configuration of a Y-axis motor. Magnetic flux 108 is formed by permanent magnet 105 and U-shaped yoke 506. A Y-axis thrust 112Y is generated by the Lorentz force depending on the direction 113 of current flowing through coil 107. To extend the stroke in the Y-axis direction, the length of permanent magnet 105 in the Y-axis direction must be increased, which increases the dimension of yoke 506 in the Y-axis direction.

[0017] 5 shows an example of the configuration of a Z-axis motor. The magnetic attraction force 401 between the permanent magnet 105 and the guide yoke 514 is used to compensate for gravity in the levitation part. The magnetic flux 108 is formed in a loop inside the guide yoke 514 and the back yoke 403. The magnetic flux 108 is increased or decreased depending on the direction 113 of the current flowing through the coil 107, and the magnetic attraction force 401 is increased or decreased. This makes it possible to control the force in the Z-axis direction.

[0018] 6 shows an example of a vibration mode in which yoke 504 bends in the Y-axis direction. Unlike yoke 506, which can be fixed to Y table 109 over its entire length, yoke 504 is fixed only at both ends, and therefore tends to vibrate in a bow-like mode in the Y-axis direction as shown in FIG.

[0019] Comparative Example 3 Figure 7 shows an example configuration of a magnetically levitated planar stage device of Comparative Example 3. A coil 704 is embedded in a levitation table 703. The position and orientation of the levitation table 703 are controlled with six degrees of freedom by electromagnetic forces between the coil 704 and a magnet array 705 arranged on the fixed side. This allows for contactless support and positioning. A motor capable of long-stroke movement within two axes in the XY plane is called a planar motor. This type of magnetically levitated planar stage device has a lighter, uniform moving mass in both the X-axis and Y-axis directions, resulting in high responsiveness compared to a stack-type magnetically levitated stage device such as that shown in Figure 2. However, leakage magnetic flux from the magnet array 705 makes it difficult to install in a charged particle beam device.

[0020] Figure 8 shows an example configuration of a planar motor of Comparative Example 3. The magnet array 705 shown in Figure 7 is configured in a staggered layout of magnets 805a with north poles on top and magnets 805b with south poles on top, as shown in Figure 8. The coils that generate thrust in the X-axis and Z-axis directions on the levitation table side are configured with U-phase coils 808, V-phase coils 809, and W-phase coils 810. In Figure 8, groups 807b of magnets 805b with their south poles facing up, i.e., toward the positive side in the Z-axis direction, are shown surrounded by dotted lines. Each group 807b can be considered a single south-pole-on magnet, and the groups between them can be considered north-pole-on magnets. Consider the B-B cross section of this.

[0021] FIG. 9 shows a cross-sectional view of the planar motor of Comparative Example 3 shown in FIG. 8 taken along the line B-B. Here, group 807b in FIG. 8 is referred to as south-pole magnet 807b, and the portion between south-pole magnets 807b that can be considered the north-pole upper magnet is referred to as north-pole magnet 807a. When coil current 903 is generated with respect to horizontal component 901 of magnetic flux 108 formed by north-pole magnet 807a and south-pole magnet 807b, vertical thrust 905 is generated by the Lorentz force. Furthermore, horizontal thrust 906 is generated by vertical component 902 of magnetic flux and coil current 904. By controlling the current values ​​of U-phase coil 808, V-phase coil 809, and W-phase coil 810 in FIG. 8 in the same manner as a three-phase AC linear motor, desired thrust in the X-axis and Z-axis directions can be obtained. Furthermore, by rotating the orientation of the coils in FIG. 8 by 90 degrees around the Z-axis, thrust in the Y-axis and Z-axis directions can be generated. This allows the planar motor to generate thrust in two axial directions.

[0022] That is, in a stack-type magnetic levitation stage device such as that shown in Figure 2, which uses linear motors such as those shown in Figures 3 to 5, the leakage magnetic field is small but it is difficult to achieve highly responsive movement on the scale of several hundred mm in two axes, X and Y. In contrast, in a magnetic levitation planar stage device such as that shown in Figure 7, it is possible to achieve highly responsive movement on the scale of several hundred mm in two axes, X and Y, but the leakage magnetic field is large and it is difficult to install it in a charged particle beam device.

[0023] To summarize the issues in the above comparative examples, the stage device of comparative example 1 has the issue of low positioning accuracy of the sample 104. The magnetic levitation stage device of comparative example 2 has the issue of difficulty in highly responsive movement (high-speed positioning) on ​​the scale of several hundred mm in two axes (X and Y). The magnetic levitation planar stage device of comparative example 3 has the issue of large leakage magnetic fields. Stage devices that solve these issues in comparative examples 1 to 3 will be described below.

[0024] Fig. 10 is a schematic diagram of the stage device 1 of Example 1. Fig. 11 is a cross-sectional view of the stage device in the YZ plane. Note that, for ease of understanding, part of the configuration shown in Fig. 11 is omitted from Fig. 10. In the following, the Z-axis direction corresponds to the vertical direction, the Y-axis direction corresponds to the first horizontal direction, and the X-axis direction corresponds to the second horizontal direction.

[0025] As shown in Fig. 10, the stage device 1 includes a Y table 109 (first table). The Y table 109 is movable in the Y-axis direction along a Y-axis guide 110. As shown in Fig. 11, the Y table 109 includes a first side wall 109a and a second side wall 109b that face each other in the Y-axis direction and extend in the X-axis direction, and a bottom 109c that connects the first side wall 109a and the second side wall 109b.

[0026] In this embodiment, the support section is configured to include support columns 509 and water-cooling jacket 508 shown in Figure 11. The support section is located between first side wall 109a and second side wall 109b of Y table 109. Furthermore, scale head 801 is fixed to water-cooling jacket 508 and recognizes scale plate 802 fixed to bottom 109c of Y table 109. Based on the recognition result of scale head 801, stage device 1 determines the relative position of top table 101 with respect to Y table 109.

[0027] A top table 101 (second table) is installed on the upper end of a support column 509. The top table 101 is provided with a bar mirror 102 used to measure the position of the top table 101, and a sample stage 103 on which a sample 104 is placed. The top table 101 is magnetically levitated relative to a Y table 109 and is movable within a horizontal plane. The elements fixed to the support, such as the top table 101, the two-axis motor coil 804, and the coil 501, constitute a levitation part that levitates relative to the Y table 109.

[0028] A water-cooling pipe 507 passes through the water-cooling jacket 508, and cools the components fixed to the water-cooling jacket 508. In particular, in this embodiment, the water-cooling jacket 508 cools the two-axis motor coil 804, the coil 501, and the scale head 801. This makes it possible to suppress heat generation from heat sources such as the two-axis motor coil 804 and the coil 501.

[0029] As shown in FIG. 11, the stage device 1 of this embodiment has a biaxial motor equipped with a biaxial motor yoke 803 and a biaxial motor coil 804 between the first side wall 109 a and the support portion, and between the second side wall 109 b and the support portion.

[0030] The biaxial motor yoke 803 has an upper member 921, a lower member 922, and an upper / lower yoke connecting portion 920. The biaxial motor yoke 803 located between the first side wall 109a and the support portion is fixed to the first side wall 109a, and the biaxial motor yoke 803 located between the second side wall 109b and the support portion is fixed to the second side wall 109b.

[0031] The stage device includes a lower magnet array 805 provided on the upper surface of a lower member 922 of a biaxial motor yoke 803, and an upper magnet array 806 provided on the lower surface of an upper member 921. Figure 12 is a cross-sectional view taken along the line A-A in Figure 11. The lower magnet array 805 has north-pole magnets 805a and south-pole magnets 805b arranged in square compartments arranged in a lattice pattern so that adjacent compartments have different magnetic poles. The lower magnet array 805 of this embodiment is arranged so that a diagonal direction DD1 of one of the compartments is parallel to the Y-axis direction, and a diagonal direction DD2 of the other compartment is parallel to the X-axis direction.

[0032] The two-axis motor coil 804 includes a first three-phase coil 923 and a second three-phase coil 924. As shown in FIG. 11 , the first three-phase coil 923 and the second three-phase coil 924 are each located between an upper member 921 and a lower member 922 of the two-axis motor yoke 803 and fixed to the support. As shown in FIG. 12 , the first three-phase coil 923 includes three first rectangular coils. The three first rectangular coils have their axial directions aligned in the Z-axis direction (vertical direction) and are aligned in a short-side direction SD1. The first three-phase coil 923 is fixed to the water-cooled jacket 508 so as to be located between the support and the side wall 109 a or 109 b of the Y table 109. In this case, the first three-phase coil 923 is arranged such that the short-side direction SD1 of the first rectangular coil is parallel to one diagonal direction DD1 of the sections of the lower magnet array 805. The second three-phase coil 924 has three second rectangular coils. The three second rectangular coils have their axial directions aligned in the Z-axis direction (vertical direction) and are aligned in the short-side direction SD2. The second three-phase coil 924 is fixed to the water-cooled jacket 508 so as to be positioned between the support and the side wall 109a or 109b of the Y table 109. In this case, the second three-phase coil 924 is arranged so that the short-side direction SD2 of the second rectangular coils is parallel to the other diagonal direction DD2 of the sections of the lower magnet array 805.

[0033] The functions of the first three-phase coil 923, the second three-phase coil 924, the lower magnet array 805, and the upper magnet array 806 will be described using FIGS. 13 to 16. FIG. 13 shows the lower magnet array 805 and the first three-phase coil 923 located above it. The lower magnet array 805 can be considered as having virtual north poles YN and virtual south poles YS alternately arranged in the Y-axis direction. Here, the virtual north poles YN are regions where north-pole magnets 805a are dominant, and the virtual south poles YS are regions where south-pole magnets 805b are dominant. The boundary between adjacent virtual north poles YN and virtual south poles YS can be set to pass through the midpoints of the sides of the sections in which the magnets are arranged. FIG. 14 shows the lower magnet array 805 and the second three-phase coil 924 located above it. The lower magnet array 805 can be considered as having virtual north poles XN and virtual south poles XS alternately arranged in the X-axis direction. Similarly, the virtual north pole XN is an area where the north pole magnet 805a is dominant, and the virtual south pole XS is an area where the south pole magnet 805b is dominant, and the boundary between adjacent virtual north poles XN and virtual south poles XS can be set to pass through the midpoint of the side of the section in which the magnets are arranged. Therefore, the stage device 1 of this embodiment can generate thrust in two axes by the Y-axis thrust 925 and the X-axis thrust 926.

[0034] On the other hand, Figure 15 is a view of the upper magnet array 806 as seen from the negative side in the Z-axis direction. Similar to the lower magnet array 805 shown in Figure 12, the upper magnet array 806 has north-pole magnets 806a and south-pole magnets 806b arranged in square sections arranged in a grid pattern, with adjacent sections having different magnetic poles. Furthermore, the upper magnet array 806 has north-pole magnets 806a and south-pole magnets 806b arranged so that each section faces a section of the lower magnet array 805 vertically and the magnetic pole of each section is different from the magnetic pole of the opposing section of the lower magnet array 805. As a result, the upper magnet array 806 can be considered, like the lower magnet array 805, to have virtual north poles YN and virtual south poles YS arranged alternately in the Y-axis direction. Furthermore, the upper magnet array 806 can also be considered to have virtual north poles XN and virtual south poles XS arranged alternately in the X-axis direction.

[0035] Figure 16 is a side view of the biaxial motor yoke 803. As shown in Figures 15 and 16, the upper magnet array 806 has virtual south poles YS and virtual north poles YN alternately arranged in this order from the negative side to the positive side in the Y-axis direction. On the other hand, as shown in Figures 13 and 16, the lower magnet array 805 has virtual north poles YN and virtual south poles YS alternately arranged in this order from the negative side to the positive side in the Y-axis direction. Therefore, as shown in Figure 16, the upper magnet array 806 and the lower magnet array 805 have different magnetic poles in the opposing portions, and magnetic flux 108 is generated that flows from one side of the upper magnet array 806 to the other side of the lower magnet array 805.

[0036] The magnetic flux 108 shown in FIG. 16 causes the first three-phase coil 923 and the second three-phase coil 924 to generate thrust. First, let's look at one rectangular coil constituting the first three-phase coil 923. As shown in FIG. 13 , the rectangular coil has a width in the short direction that is at least half the length of the diagonal of the section but less than the length of the diagonal of the section, and the long side of the rectangular coil is sized so that it is included in the virtual north pole YN (virtual south pole YS) and the opposing side is included in the virtual south pole YS (virtual north pole YN). Therefore, when a current is passed through the rectangular coil, thrusts are generated in the same direction in the Y direction in the rectangular coil portion above the virtual north pole YN and the rectangular coil portion above the virtual south pole YS, thereby generating a Y-axis thrust 925. For the same reason, an X-axis thrust 926 is also generated when a current is passed through the rectangular coil of the second three-phase coil 924 shown in FIG. 14 . Furthermore, by combining three rectangular coils, each of which serves as a U-phase coil, a V-phase coil, and a W-phase coil, into a three-phase coil, the driving distance can be extended.

[0037] Thrust can also be generated at the short sides of each rectangular coil constituting the first three-phase coil 923 and the second three-phase coil 924. However, the X-axis direction thrust generated by the first three-phase coil 923 can be kept negligible relative to the X-axis direction thrust 926 generated by the second three-phase coil 924, and the Y-axis direction thrust generated by the second three-phase coil 924 can be kept negligible relative to the Y-axis direction thrust 925 generated by the first three-phase coil 923.

[0038] Furthermore, since the magnetic circuit of the stage device 1 of this embodiment is closed between the upper member 921 and the lower member 922, there is little leakage magnetic field from the upper magnet array 806 and the lower magnet array 805 to the outside, and the device can be mounted on a charged particle beam device.

[0039] 12 , the first three-phase coils 923 and the second three-phase coils 924 are arranged alternately with respect to the water-cooled jacket 508. That is, the two-axis motor yoke 803 located between the first side wall 109 a and the support portion includes the first three-phase coil 923 on one end side of the first side wall 109 a and the second three-phase coil 924 on the other end side of the first side wall 109 a, and the two-axis motor yoke 803 located between the second side wall 109 b and the support portion includes the second three-phase coil 924 on one end side of the second side wall 109 b that faces one end of the first side wall 109 a in the Y-axis direction and the first three-phase coil 923 on the other end side of the second side wall 109 b.

[0040] In this way, by arranging the first three-phase coils 923 fixed to both sides of the water-cooled jacket 508 in the Y-axis direction and offsetting them in the X-axis direction so that they do not overlap in the Y-axis direction, it is possible to generate Y-axis thrusts 925 in the two first three-phase coils 923 at intervals in the X-axis direction, and by providing a difference in the Y-axis thrusts 925, it is possible to generate torque in the rotational direction about the Z-axis, thereby controlling the attitude about the Z-axis. Similarly, by arranging the second three-phase coils 924 fixed to both sides of the water-cooled jacket 508 in the X-axis direction and offsetting them in the X-axis direction so that they do not overlap in the Y-axis direction, it is possible to generate two X-axis thrusts 926 in the two second three-phase coils 924 at intervals in the X-axis direction, and by providing a difference in the X-axis thrusts 926, it is possible to control the attitude about the Z-axis.

[0041] Next, the Z-axis thrust will be described with reference to FIG. 11 . The stage device 1 includes a back yoke 403, a magnetic levitation magnet 502, and a coil 501 as components related to the Z-axis thrust. The back yoke 403 is fixed to the water-cooling jacket 508 so as to be positioned below the lower member 922 of the two-axis motor yoke 803 in the Z-axis direction (vertical direction). The magnetic levitation magnet 502 is fixed to the upper surface of the back yoke 403 and generates a magnetic attraction force 401 with respect to the lower member 922. This magnetic attraction force 401 serves as a levitation force for compensating for the gravity of the support unit and the top table 101, magnetically levitating the support unit and the top table 101, and also serves as a Z-axis thrust. The coil 501 is fixed to the upper surface of the back yoke 403 so as to be positioned between the two-axis motor yoke 803 and the magnetic levitation magnet 502. The magnetic attraction force 401 is controlled by passing a current through the coil 501. In this way, the back yoke 403, the magnetic levitation magnet 502, and the coil 501, together with the lower member 922 of the two-axis motor yoke 803, constitute a vertical motor. Note that the coil 501 can be, for example, a single-phase coil whose axial direction is in the Z-axis direction.

[0042] The vertical motor magnetically levitates the levitation part so that the heights of the first three-phase coils 923 and second three-phase coils 924 of the biaxial motor coils 804 located on both sides of the support part coincide with the height of the center of gravity 702 of the levitation part. This causes the drive center 701 of the biaxial motor formed by the biaxial motor yoke 803 and the biaxial motor coils 804 to coincide with the center of gravity 702 of the levitation part. As a result, the pitching moment caused by movement of the levitation part in the X-axis and Y-axis directions is reduced, and the current to the coils 501 used for attitude fluctuation and attitude control can also be reduced, enabling less heat generation.

[0043] In the vertical motor of this embodiment, the biaxial motor yoke 803 covers the magnetic levitation magnet 502, thereby shielding the leakage magnetic field from the magnetic levitation magnet 502. Also, as shown in Fig. 11, the magnetic levitation magnet 502 is configured to adhere to the underside of the biaxial motor yoke 803, so there is no need to provide the guide yoke 514 shown in Fig. 2, and the weight of the stage device 1 can be reduced.

[0044] The stage device 1 of this embodiment is configured to include a magnetic levitation guide that provides non-contact movement guidance for the top table 101, and this configuration improves positioning accuracy. Furthermore, by including a planar motor, the stage device 1 of this embodiment is able to move the biaxial motor coil 804 at high speed within the XY biaxial plane within the range of the lower member 922 shown in Fig. 12, and when applied to a semiconductor inspection device or the like, it becomes possible to perform positioning at high speeds comparable to those of a magnetic levitation planar stage device within a range of about 20 mm, which corresponds to a typical single chip.

[0045] As described above, the stage device 1 of this embodiment can suppress external leakage of magnetic fields. This makes it possible to apply it to devices that require a low magnetic field, such as charged particle beam devices. Furthermore, the stage device 1 of this embodiment does not require the X-axis linear motor shown in FIG. 2 and therefore reduces the amount of magnetic material, thereby reducing interference with the magnetic field formed by the magnetic deflection lens of the electron optical system, which can be a problem in charged particle beam devices. This reduces distortion of the electron beam and allows for a better image to be obtained.

[0046] In the stage device 1 of this embodiment, the biaxial motor yoke 803 is fixed to the side wall 109a or 109b of the Y table 109 along the entire X-axis direction, which is its extension direction, making it less susceptible to vibration and increasing its natural frequency. This improves the control bandwidth, which was previously limited by the natural frequency of the yoke 504 in the magnetic levitation stage device shown in FIG. 2 . It also reduces the number of parts and shortens lead time. Note that the arrangement shown in the example is not limited to the biaxial motor yoke 803, as long as the required control bandwidth can be obtained, even if it is not fixed to the side wall 109a or 109b of the Y table 109. For example, it may be possible for the biaxial motor yoke 803 to have a sufficiently short length in the X-axis direction or to have high rigidity and be less susceptible to vibration.

[0047] In this embodiment, an example has been described in which the two-axis motor coil 804 has a first three-phase coil 923 and a second three-phase coil 924, but this is not limited to this, and it is sufficient if the two-axis motor coil 804 has one or more first rectangular coils and one or more second rectangular coils.

[0048] Furthermore, in this embodiment, an example has been described in which the lower magnet array 805 and the upper magnet array 806 are arranged in a square lattice pattern, but this is not limited to this. For example, a Halbach array may be used in which a gap is provided between the N-pole magnet 805a and the S-pole magnet 805b, and a magnet whose magnetic field is oriented in the XY plane is inserted into the gap.

[0049] As described above, according to this embodiment, it is possible to provide a stage device that can suppress vibration of the stator of the motor and that is capable of high-speed positioning.

[0050] 17 is a diagram illustrating a modification of biaxial motor yoke 803. Biaxial motor yoke 803 is integral with an upper member 921, a lower member 922, and an upper / lower yoke connecting portion 920. A notch is provided in the lower portion of biaxial motor yoke 803, and this notch is fixed to side wall 109a or 109b of Y table 109.

[0051] (Variation 2) In this variation, a variation of the lattice orientation of the lower magnet array 805 and the orientations of the first three-phase coil 923 and the second three-phase coil 924 will be described. Fig. 18 is a cross section taken along line A-A in Fig. 11 in variation 2. In Example 1, as shown in Fig. 12, the diagonal direction DD1 of the sections of the lower magnet array 805 and the short-side direction SD1 of the first rectangular coil of the first three-phase coil 923 are parallel to the Y-axis direction, and the diagonal direction DD2 and the short-side direction SD2 of the second rectangular coil of the second three-phase coil 924 are parallel to the X-axis direction. In this modified example, the X'-axis and Y'-axis of a coordinate system in which the X-axis and Y-axis directions are rotated 45° around the Z-axis are used, and the diagonal direction DD1 of the sections of the lower magnet array 805 and the short-side direction SD1 of the first rectangular coil of the first three-phase coil 923 are parallel to the Y'-axis direction, while the diagonal direction DD2 and the short-side direction SD2 of the second rectangular coil of the second three-phase coil 924 are parallel to the X'-axis direction. In this case, a Y'-axis thrust is generated in the first three-phase coil 923, and an X'-axis thrust is generated in the second three-phase coil 924. The stage device 1 of this embodiment generates X-axis thrust and Y-axis thrust by the resultant force of the Y'-axis thrust generated in the first three-phase coil 923 and the X'-axis thrust generated in the second three-phase coil 924.

[0052] In this modified example, the lower magnet array 805 has been described, but since the upper magnet array 806 is configured so that each section faces a section of the lower magnet array 805, the grid orientation of the upper magnet array 806 also changes in the same way.

[0053] 19 is a cross section taken along line A-A of FIG. 11 in Modification 3. This modification describes a modification of the configuration of the first three-phase coil 923 and the second three-phase coil 924. Note that the upper magnet array 806 and the lower magnet array 805 in this modification are the same as those in Modification 2.

[0054] As shown in FIGS. 12 and 18 , the first three-phase coil 923 of Example 1 and Modification 1 has three first rectangular coils arranged in the short-side direction SD1 with their short sides aligned in a straight line. The same is true for the second three-phase coil 924. In contrast, the first three-phase coil 923 of this modification has three first rectangular coils arranged in the short-side direction SD1 with their short sides offset in a stepped manner. Similarly, the second three-phase coil 924 of this modification has three second rectangular coils arranged in the short-side direction SD2 with their short sides offset in a stepped manner. This reduces the coil width 933 and increases the movable stroke in the Y-axis direction. Furthermore, in FIG. 19 , the corners of the first rectangular coils are arranged to overlap in the X-axis direction. Similarly, the corners of the second rectangular coils are arranged to overlap in the X-axis direction. This further reduces the coil width 933.

[0055] In this embodiment, a vacuum apparatus equipped with the above-described stage apparatus 1 will be described. Fig. 17 is a schematic cross-sectional view of a semiconductor measurement apparatus 2 equipped with the stage apparatus 1 of the present disclosure. Here, a charged particle beam apparatus, particularly a semiconductor measurement apparatus, will be described as an example of the vacuum apparatus, but the present invention is not limited to this. Note that the stage apparatus 1 is shown in a simplified form in Fig. 17.

[0056] The semiconductor measuring device 2 of this embodiment includes a stage device 1 that positions the object, and a vacuum chamber 951 that houses the stage device 1. The semiconductor measuring device 2 is, for example, a critical dimension SEM that is an application device of a scanning electron microscope (SEM).

[0057] The semiconductor measuring device 2 includes, for example, a stage device 1, a vacuum chamber 951, an electron optical system lens barrel 952, a vibration control mount 953, a laser interferometer 954, and a controller 955. The vacuum chamber 951 houses the stage device 1, and its interior is depressurized by a vacuum pump (not shown) to create a vacuum state at a pressure lower than atmospheric pressure. The vacuum chamber 951 is supported by the vibration control mount 953.

[0058] The semiconductor measuring device 2 positions a sample 104 such as a semiconductor wafer using a stage device 1, irradiates an electron beam from an electron optical system lens barrel 952 onto the object, images the pattern on the object, measures the line width of the pattern, and evaluates its shape accuracy. In the stage device 1, a laser interferometer 954 measures the position of a bar mirror 102, a scale head 801 measures the position of a Y table 109 on which a scale plate 802 is mounted, and a controller 955 controls the positioning of a sample such as a semiconductor wafer held on a sample stage 103.

[0059] The semiconductor measurement device according to this embodiment is equipped with a low-vibration stage device with a two-axis motor structure, which reduces vibration during positioning of an object such as a wafer, shortens positioning time, and suppresses magnetic field leakage. This improves the measurement accuracy of the semiconductor measurement device as a charged particle beam device. Furthermore, because the stage device uses a magnetic levitation mechanism, it can be easily applied to semiconductor measurement devices, which are vacuum devices, and can achieve excellent effects such as reduced contamination and heat generation.

[0060] As described above, according to this embodiment, it is possible to provide a stage device, a vacuum device, and a charged particle beam device that are capable of suppressing vibration of the stator of the motor and enabling high-speed positioning.

[0061] The above has described in detail an embodiment of the present invention using the drawings, but the specific configuration is not limited to this embodiment, and even if there are design changes and the like within the scope of the present invention, they are also included in the present invention.

[0062] 101: Top table (second table), 102: Bar mirror, 103: Sample stage, 104: Sample, 105: Permanent magnet, 107: Coil, 108: Magnetic flux, 109: Y table (first table), 110: Y axis guide, 111: X table, 112X: X axis thrust, 112Y: Y axis thrust, 113: Current direction, 120: X axis guide, 401: Magnetic attraction force, 402: Guide yoke, 403: Back Yoke, 501: Coil, 502: Magnetic levitation magnet, 504: X-axis motor yoke, 506: Y-axis motor yoke, 507: Water cooling pipe, 508: Water cooling jacket, 509: Support column, 514: Guide yoke, 701: Drive center, 702: Center of gravity, 703: Levitation table, 704: Coil, 705: Magnet array, 706: Leakage magnetic flux, 801: Scale head, 802: Scale plate, 803: Biaxial motor 804: two-axis motor coil, 805: lower magnet array, 805a: north pole magnet, 805b: south pole magnet, 806: upper magnet array, 806a: north pole magnet, 806b: south pole magnet, 807a: north pole magnet, 807b: south pole magnet, 808: U-phase coil, 809: V-phase coil, 810: W-phase coil, 901: horizontal component of magnetic flux, 902: vertical component of magnetic flux, 903: coil current, 904: coil current, 905: vertical thrust, 906: horizontal thrust, 920: upper and lower yoke connection part, 921: upper member, 922: lower member, 923: first three-phase coil, 924: second three-phase coil, 925: Y-axis thrust, 926: X-axis thrust, 933: coil width, DD1: one diagonal direction of the section, DD2: the other diagonal direction of the section, SD1: short side direction of the first rectangular coil, SD2: short side direction of the second rectangular coil.

Claims

1. A stage device for positioning a sample table within a horizontal plane, comprising: a first table; a second table on which the sample table is provided and which is movable within the horizontal plane while being magnetically levitated relative to the first table; a support section for supporting the second table; a first two-axis motor provided on the support section; and a second two-axis motor provided on the support section, wherein the first two-axis motor and the second two-axis motor each comprise: a yoke comprising an upper member and a lower member; and first and second rectangular coils located between the upper member and the lower member, each fixed to the support section, the axial direction of which is vertical; and a magnet array is provided on the lower surface of the upper member and the upper surface of the lower member, in which magnets are arranged in square compartments arranged in a lattice pattern such that the magnetic poles of adjacent compartments are different, and the magnet array provided on the lower surface of the upper member and the magnet array provided on the upper surface of the lower member have magnets in compartments facing each other in the vertical direction which have different magnetic poles.

2. A stage device as described in claim 1, characterized in that the first table is movable in a first horizontal direction parallel to the horizontal plane, and has a first side wall and a second side wall facing each other in the first horizontal direction and extending in a second horizontal direction parallel to the horizontal plane and perpendicular to the first horizontal direction, the support portion is located between the first side wall and the second side wall of the first table, the first two-axis motor is located between the first side wall and the support portion, the second two-axis motor is located between the second side wall and the support portion, and the yokes of the first two-axis motor and the second two-axis motor are fixed to the first side wall or the second side wall of the first table, respectively.

3. A stage device as described in claim 2, characterized in that the first two-axis motor is provided with the first rectangular coil on one end side of the first side wall and the second rectangular coil on the other end side of the first side wall of the first table, and the second two-axis motor is provided with the second rectangular coil on one end side of the second side wall that faces one end of the first side wall in the first horizontal direction and the first rectangular coil on the other end side of the second side wall.

4. A stage device as described in claim 2, characterized in that the short side direction of the first rectangular coil is parallel to one diagonal direction of the section of the magnet array, and the short side direction of the second rectangular coil is parallel to the other diagonal direction of the section of the magnet array.

5. A stage device according to claim 4, wherein the first two-axis motor has a first three-phase coil having three of the first rectangular coils arranged in a diagonal direction on one side of the magnet array section, and the second two-axis motor has a second three-phase coil having three of the second rectangular coils arranged in a diagonal direction on the other side of the magnet array section.

6. A stage device according to claim 5, wherein one diagonal direction of the sections of the magnet array is shifted at an angle of 45 degrees with respect to the first horizontal direction.

7. A stage device according to claim 6, characterized in that the short sides of the three first rectangular coils of the first three-phase coil are offset in a stepped manner, and the short sides of the three second rectangular coils of the second three-phase coil are offset in a stepped manner.

8. A stage device according to claim 5, characterized in that the other diagonal direction of the magnet array section is parallel to the second horizontal direction.

9. A stage device according to claim 2, wherein the yoke has a U-shaped cross section perpendicular to the second horizontal direction.

10. A stage device as described in claim 1, comprising: a back yoke fixed to the support part so as to be positioned vertically below the lower member of the yoke; a magnetic levitation magnet fixed to the upper surface of the back yoke and generating a magnetic attraction force with respect to the lower member of the yoke; and a coil fixed to the upper surface of the back yoke so as to be positioned between the lower member of the yoke and the magnetic levitation magnet and controlling the magnetic attraction force, wherein the back yoke, the magnetic levitation magnet and the coil, together with the lower member of the yoke, constitute a vertical motor.

11. A stage device according to claim 10, characterized in that the vertical motor magnetically levitates the floating part so that the height at which the first rectangular coil and the second rectangular coil of the first two-axis motor and the second two-axis motor, respectively, are positioned coincides with the height of the center of gravity of the floating part including the support part and the second table.

12. A stage device as described in claim 1, characterized in that the width of the first rectangular coil in the short direction is more than half the diagonal length of the section and less than the diagonal length of the section, and the width of the second rectangular coil in the short direction is more than half the diagonal length of the section and less than the diagonal length of the section.

13. The stage device according to claim 1, wherein the magnet array is a Halbach array magnet array.

14. A stage device according to claim 2, further comprising a guide for guiding the movement of said first table in said first horizontal direction.

15. A vacuum apparatus comprising: a stage apparatus according to any one of claims 1 to 14; and a vacuum chamber that houses the stage apparatus and has a vacuum state inside.

16. A charged particle beam device comprising: a stage device according to any one of claims 1 to 14; a vacuum chamber that houses the stage device and has an internal vacuum; and an electron optical system barrel that irradiates an electron beam onto a sample placed on the stage device.

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