Linear motor, positioning device, processing device, device manufacturing method

Abstract

To provide a linear motor or the like that can reduce the influence of the gap between coil units with a simple configuration. [Solution] A linear motor comprising a movable element 20 equipped with permanent magnets 6N and 6S, and a stator equipped with a plurality of coils 4 arranged along the direction of movement of the movable element 20, which exerts a magnetic driving force on a magnetic circuit along the direction of movement according to the driving current flowing through the plurality of coils 4, wherein the plurality of coils 4 are divided and mounted in a plurality of coil units 10A and 10B which is fewer than the total number of coils 4, and in each coil unit 10A and 10B, the plurality of coils 4 are arranged at substantially constant intervals, and for two adjacent coil units 10A and 10B in the direction of movement, the interval between the coils located at their opposing ends is a constant interval plus an adjustment interval of 180 degrees, which is converted to the electrical angle of the driving current.

Description

Technical Field

[0001] The present disclosure relates to a linear motor or the like.

Background Art

[0002] Patent Document 1 discloses a moving magnet (MM) type linear motor including a mover provided with a permanent magnet and a stator provided with a plurality of coils arranged along the moving direction of the mover. Since the stroke of the mover is long, a long stator is formed by arranging a plurality of coil units (modules) along the moving direction.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Although there is a gap between adjacent coil units, in Patent Document 1, by measuring in advance the electrical angle due to the gap, smooth driving when the mover straddles a plurality of coil units is realized. However, it is cumbersome to measure all the gaps between the coil units and finely adjust the driving timing etc. in each coil unit according to each of them.

[0005] The present disclosure has been made in view of such a situation, and an object thereof is to provide a linear motor or the like that can reduce the influence of the gap between coil units with a simple configuration.

Means for Solving the Problems

[0006] To solve the above problems, a linear motor according to one aspect of the present disclosure comprises a movable element having a magnetic circuit, and a stator having a plurality of coils arranged along the direction of movement of the movable element, which exerts a magnetic driving force on the magnetic circuit along the direction of movement in accordance with the drive current flowing through the plurality of coils, wherein the plurality of coils are divided and mounted in a plurality of coil units which is fewer than the total number of coils, and in each coil unit the plurality of coils are arranged at substantially constant intervals, and for two adjacent coil units in the direction of movement, the interval between the coils located at their opposing ends is a constant interval plus an adjustment interval of 180 degrees in terms of the electrical angle of the drive current.

[0007] According to this embodiment, continuity in the driving of a movable element spanning two coil units can be achieved with a simple configuration in which the distance between the coils located at each end of two adjacent coil units is set to an adjustment interval of 180 degrees when converted to an electrical angle.

[0008] Another aspect of this disclosure is a positioning device, which is powered by the linear motor described above.

[0009] Another aspect of the present disclosure is a processing apparatus that processes an object positioned by the positioning apparatus described above.

[0010] Another aspect of this disclosure is a device manufacturing method, which manufactures a device through processing of a workpiece by the processing apparatus described above.

[0011] Furthermore, any combination of the above components, as well as any representations thereof converted into methods, apparatus, systems, recording media, computer programs, etc., are also included in this disclosure. [Effects of the Invention]

[0012] According to this disclosure, the influence of gaps between coil units can be reduced with a simple configuration. [Brief explanation of the drawing]

[0013] [Figure 1] This is a schematic plan view showing the stage equipment. [Figure 2] This is a perspective view showing the armature of a linear motor. [Figure 3] A saddle-shaped coil is schematically shown. [Figure 4] This is a schematic cross-sectional view of the movable element and the armature in the direction of movement of the movable element. [Figure 5] A schematic diagram shows the configuration of a movable element equipped with a permanent magnet and a coil unit that drives it. [Modes for carrying out the invention]

[0014] The following describes in detail the forms (hereinafter also referred to as embodiments) for carrying out this disclosure, with reference to the drawings. In the description and / or drawings, identical or equivalent components, members, processes, etc., are denoted by the same reference numerals, and redundant descriptions are omitted. The scale and shape of the illustrated parts are set for convenience in order to simplify the description and are not to be interpreted restrictively unless otherwise specified. The embodiments are illustrative and do not limit the scope of this disclosure in any way. Not all features or combinations thereof presented in the embodiments are necessarily essential to this disclosure. For convenience, embodiments are presented by breaking them down into components for each function and / or group of functions that realize them. However, one component in an embodiment may actually be realized by a combination of multiple components as separate entities, and multiple components in an embodiment may actually be realized by a single component as a whole. Furthermore, multiple embodiments and modifications may be disclosed in parallel, and any components of each embodiment and / or modification may be combined in any manner as long as they do not interfere with each other's functions.

[0015] Figure 1 is a schematic plan view showing a stage device 100 as a positioning device or drive device to which a linear motor according to this embodiment can be applied. The stage device 100 is an XY stage that positions a table, which is a driven body on which a workpiece such as a semiconductor wafer is placed, in the X-axis direction (left-right direction in Figure 1) and the Y-axis direction (up-down direction in Figure 1). The stage device 100 includes a pair of Y stages 120 that extend in the Y-axis direction and drive the table in the Y-axis direction, an X stage 130 that extends in the X-axis direction and drives the table in the X-axis direction and is integrated with the table, and a surface plate 140. The pair of Y stages 120 are connected to both ends of the X stage 130 in the X-axis direction via sliders 124. The Y stages 120 and X stages 130 form an H shape when viewed from above.

[0016] Of the components of the stage apparatus 100, at least the table, Y-stage 120, and X-stage 130 may be housed in a vacuum chamber whose interior is kept under vacuum. In this specification, "vacuum" refers to a space filled with gas at a pressure lower than normal atmospheric pressure. Vacuum is classified into low vacuum (100 kPa to 100 Pa), medium vacuum (100 Pa to 0.1 Pa), and high vacuum (0.1 Pa to 100 Pa). -5 Pa), ultra-high vacuum (10 -5 Pa~10 -8 Pa), extremely high vacuum (10 -8 Vacuum levels are classified as follows: Pa or less. The stage apparatus 100 according to this embodiment may be used in any of the above vacuum environments. Furthermore, the stage apparatus 100 according to this embodiment may be used in a non-vacuum environment that does not fall under any of the above categories.

[0017] The X-stage 130 and Y-stage 120 are each provided with linear motors 2X and 2Y, respectively, as described later. The magnetic driving force or linear power generated by each linear motor 2X and 2Y in the X-axis or Y-axis direction linearly drives the table, which is the driven body, in the X-axis or Y-axis direction.

[0018] The linear motor 2X responsible for linear drive in the X-axis direction includes a stator 3 that constitutes a track in the X-axis direction and a mover 20 that is movable in the X-axis direction along the stator 3. A table as a driven body is fixed to the mover 20 and moves integrally. The pair of linear motors 2Y responsible for linear drive in the Y-axis direction includes a stator 3 that constitutes a track in the Y-axis direction and a mover 20 that is movable in the Y-axis direction along the stator 3. A slider 124 is fixed to the mover 20 and moves integrally.

[0019] Here, since the pair of sliders 124 are connected to both ends of the stator 3 of the linear motor 2X, the pair of linear motors 2Y linearly drive the stator 3 of the linear motor 2X together with the pair of sliders 124 in the Y-axis direction. And since there is a table on the stator 3 (track) of the linear motor 2X, the pair of linear motors 2Y linearly drive the table in the Y-axis direction.

[0020] The stage device 100 (positioning device with a linear motor as a power source) according to this embodiment, which can achieve high-precision positioning or driving regardless of whether it is in a vacuum environment or a non-vacuum environment, is suitable for use in positioning or driving a table on which a semiconductor wafer or the like as a workpiece is placed as a driven body in a semiconductor manufacturing device such as an exposure device, an ion implantation device, a heat treatment device, an ashing device, a sputtering device, a dicing device, an inspection device, a cleaning device, or a device manufacturing device such as an FPD (Flat Panel Display) manufacturing device. The processing device to which the stage device 100 according to this embodiment can be applied may be any device that positions an arbitrary workpiece for processing by the stage device 100 or the positioning device, for example, any manufacturing device, any processing device (for example, a machine tool), or any inspection device.

[0021] Figure 2 is a schematic perspective view showing the armatures 2 of the linear motors 2X and 2Y, which are provided on the X-stage 130 and Y-stage 120, respectively. In this embodiment, the armature 2 is provided on the stator 3 (Figure 1), which constitutes the trajectories in the X-axis and Y-axis directions. Although not shown in this figure, a field or magnetic circuit, such as a permanent magnet, which magnetically interacts with the armature 2 or coil unit 10, which is composed of electromagnets, is provided on the movable element 20. In other words, the linear motors 2X and 2Y in this embodiment are of the Moving Magnet (MM) type, in which a magnetic circuit is provided on the movable element 20.

[0022] The armature 2 is a long, roughly rectangular plate, and coil rows consisting of multiple coils 4 are formed on both its first surface (for example, the back side of the armature 2 in Figure 2) and its second surface (for example, the front side of the armature 2 in Figure 2). Each coil row comprises multiple coils 4 arranged along the longitudinal direction of the armature 2 (roughly the left-right direction in Figure 2). In the example in Figure 2, each coil row comprises 12 coils 4, so when three-phase alternating current is applied to each coil row, the 12 coils 4 are divided into 4 sets of three-phase coils. In this way, an integrated coil unit 10, in which multiple coils 4 are grouped together, is formed in the armature 2.

[0023] The number of coils 4 implemented in a single coil unit 10 is arbitrary. However, when a three-phase alternating current is flowed as the drive current as described above, it is preferable that the number of coils 4 implemented in a single coil unit 10 be a multiple of 3 (for example, 3, 6, 9, 12, or 15). In this case, a single coil unit 10 is equipped with integer sets (for example, 1 set, 2 sets, 3 sets, 4 sets, or 5 sets) of three-phase coils. A set of three-phase coils consists of a U-phase coil, a V-phase coil, and a W-phase coil, through which U-phase current, V-phase current, and W-phase current, respectively, flow, each having a phase difference of 120 degrees from each other.

[0024] As will be described later, in this embodiment, a plurality of coil units 10 are provided. That is, the plurality of coils 4 in this embodiment are divided and implemented in a plurality of coil units 10, which is fewer than the total number of coils 4. Here, the number of coils 4 implemented in each coil unit 10 may be uniform (for example, 12), or they may be different (for example, one coil unit 10 may have 6 coils 4, and another coil unit 10 may have 12 coils 4).

[0025] In the example shown in Figure 2, two parallel coil rows are provided on two sides of the coil unit 10, but the coil unit 10 may have only one coil row (i.e., a single column) (not shown).

[0026] The coil rows provided on the first and second surfaces of the coil unit 10 are opposed to a movable element 20 (Figure 1) having a magnetic circuit such as a permanent magnet or a field. Each coil row through which a drive current such as a three-phase alternating current flows exerts linear power on the magnetic circuit opposite to each coil row and / or on each coil row itself. The direction of this linear power is approximately the same as the direction of arrangement of each coil row (i.e., the longitudinal direction of the armature 2 or the approximate left-right direction in Figure 2), and the field (movable element 20) and the armature 2 (stator 3) move linearly relative to each other in this direction.

[0027] Furthermore, the magnetic circuits or fields in the movable element 20 facing the coil rows on the first and second sides of the coil unit 10 may be physically connected to each other or integrally formed so that the magnetic circuits on both sides (i.e., the entire movable element 20) are driven integrally relative to each other by the coil rows on both sides of the coil unit 10. In this case, approximately the same drive current may be applied to each coil 4 on the first side of the coil unit 10 and each coil 4 on the second side located approximately behind it. Alternatively, if the coil rows on the first and second sides of the coil unit 10 are offset from each other along the direction of movement, as in the case of two coil rows formed by saddle-shaped coils as shown in Figure 3, an appropriate drive current corresponding to that arrangement may be applied to each coil row.

[0028] In Figure 2, the coil unit 10 includes a substantially rectangular plate-shaped member 12 that supports each row of coils on each surface. This plate-shaped member 12 may constitute a cooling mechanism for cooling one or more coils 4 that make up the coil unit 10. Both the first and second surfaces of the plate-shaped member 12 are positioned so as to be in contact with one end face or the inner end face of each of the above-mentioned rows of coils. The cooling mechanism further includes an inlet 14 provided at one end of the plate-shaped member 12 in the direction of the arrangement of the coils 4, and an outlet 16 provided at the other end of the plate-shaped member 12 in the direction of the arrangement of the coils 4. Note that the inlet 14 and the outlet 16 may be reversed (i.e., the direction in which the refrigerant described later flows may be reversed so that the inlet 14 functions as an outlet and the outlet 16 functions as an inlet).

[0029] The inlet 14 is located at a position deviating from the arrangement direction of the coils 4, specifically above the coil 4 at one end of the coil row (the right end in Figure 2). In this specification, terms such as "upper" and "lower" are used for convenience to represent the relative positional relationship between the coil row or coil 4 and the inlet 14, etc., as shown in the drawings, and do not mean upper or lower in the vertical or gravity direction. Unless otherwise specified below, terms such as "up," "down," "left," and "right" refer to the relative direction with respect to the coil row or coil 4 shown in each figure.

[0030] An inlet 14a is provided at the top of the inlet 14 for refrigerant such as cooling water to flow in to cool the multiple coils 4. Inside the plate-shaped member 12, a flow channel structure of any shape is formed to guide the refrigerant flowing in from the inlet 14a to the outlet 16a, efficiently cooling each coil 4 along the way. The outlet 16 is located at a position deviated from the direction of the coil arrangement, specifically above the coil 4 at the other end of the coil row (the left end in Figure 2), similar to the inlet 14. An outlet 16a is provided at the top of the outlet 16 for the refrigerant that has flowed in from the inlet 14a and passed through the flow channel structure inside the plate-shaped member 12 to flow out.

[0031] As described above, the refrigerant flowing through the flow path structure within the plate-shaped member 12 simultaneously cools two coil rows that are positioned to contact both sides of the flat plate-shaped member 12. Alternatively, the coil rows may be provided on only one side of the flat plate-shaped member 12. In this case, the refrigerant flowing through the flow path structure within the plate-shaped member 12 cools one coil row that is positioned to contact one side of the flat plate-shaped member 12. Furthermore, a configuration in which one coil row is sandwiched between two plate-shaped members 12 from both sides is also possible.

[0032] Figure 4 is a schematic cross-sectional view of the movable element 20 (magnetic circuit) and the armature 2 in the direction of movement of the movable element 20 (or in the direction of arrangement of the coils 4). As illustrated in this figure, in linear motors or armatures 2 used in a vacuum environment in particular, the plate-shaped member 12 and the coils 4 are molded with an insulating resin material 5 (molding resin) such as epoxy resin to prevent the refrigerant flowing through the flow path structure within the plate-shaped member 12, or fine particles that may be scattered from the heat-generating coils 4, from contaminating the vacuum environment.

[0033] Furthermore, a base 51 for mounting the coil unit 10 to a stator 3 or the like is attached to the bottom of the coil unit 10 (armature 2), which includes the plate-shaped member 12 and coil 4 sealed by the resin material 5. Although not shown in the illustration, an inlet 14 and / or outlet 16 shown in Figure 2 may be provided on the side of the base 51 so as not to interfere with the base 51 (in this case, the vertical direction of Figure 2 and Figure 4 are reversed).

[0034] As schematically shown in Figure 4, the multiple coils 4 are arranged in two rows (the left row and the right row in Figure 4). A movable element 20 with a roughly U-shaped cross-section is provided to cover the portion of the armature 2 molded with resin material 5 from above. The movable element 20, which acts as a field magnet, is provided with pairs of permanent magnets 6 that constitute a magnetic circuit, facing the left and right rows of coils in the armature 2, respectively. Here, it is preferable that the magnetic poles (the magnetic poles on the side facing the coils 4) of the pair of permanent magnets 6 facing each other across the armature 2 are different from each other.

[0035] In other words, in the cross-section shown in the figure, if the magnetic pole on the right face of the left permanent magnet 6 is a north pole, it is preferable that the magnetic pole on the left face of the right permanent magnet 6 is a south pole, and if the magnetic pole on the right face of the left permanent magnet 6 is a south pole, it is preferable that the magnetic pole on the left face of the right permanent magnet 6 is a north pole. Here, the pair of magnetic poles of the permanent magnets 6 change along the direction of movement (the direction perpendicular to the plane of the paper in Figure 4) so ​​that the movable element 20 as a field is appropriately linearly driven by the three-phase coil as shown in Figure 2 (for example, north pole / (Pairs of S-pole permanent magnets 6 and pairs of S-pole / N-pole permanent magnets 6 are arranged alternately along the direction of movement.)

[0036] As described above, the coil unit 10, which can be used in a vacuum environment, has limitations in its length along the direction of movement because it requires molding with resin material 5 and special metal processing for a case or shell (not shown) to accommodate the vacuum. For this reason, it may be difficult to cover the entire length of the stator 3 (the trajectory of the movable element 20) with just one coil unit 10. Furthermore, even in a non-vacuum environment, if the stroke or movement distance of the movable element 20 is long, one coil unit 10 alone cannot cover it. Therefore, it is necessary to cover the entire length of the stator 3 (the trajectory of the movable element 20) by arranging multiple coil units 10 along the direction of movement.

[0037] In such cases, gaps exist between adjacent coil units 10, causing disruption in the arrangement of the coils 4. Patent Document 1 describes how smooth driving is achieved when the movable element spans multiple coil units by pre-measuring the electrical angle caused by these gaps. However, measuring all the gaps between coil units 10 and fine-tuning the driving timing of each coil unit 10 accordingly is cumbersome. Therefore, this embodiment provides a linear motor that can reduce the influence of gaps between coil units 10 with a simple configuration.

[0038] Figure 5 schematically shows the configuration of a movable element 20 equipped with N-pole permanent magnets 6N and S-pole permanent magnets 6S arranged alternately along the direction of movement (left-right direction), and a coil unit 10 according to this embodiment that drives it along the direction of movement. Figure 5A shows a comparative example when there is one coil unit 10, and Figure 5B shows an example when there are multiple coil units 10. In Figure 5B, two coil units 10A and 10B are shown as a simple example, but three or more coil units 10 may be arranged in a line along the direction of movement following the example in this figure. Figure 5 shows a cross-section including multiple coils 4 that make up the coil unit 10 and multiple permanent magnets 6 that make up the movable element 20, in a top view or bottom view in Figure 4. The left-right direction in Figure 5 is the direction of movement of the movable element 20.

[0039] In the comparative example shown in Figure 5A, one coil unit 10 comprises four sets of three-phase coils. Each three-phase coil includes a U-phase coil 4U, a V-phase coil 4V, and a W-phase coil 4W, arranged continuously along the direction of movement. As is well known, the terms U-phase, V-phase, and W-phase represent the phase difference (120 degrees apart) of the three-phase AC currents flowing through each coil 4U, 4V, and 4W, and the configuration of each coil 4U, 4V, and 4W is basically the same.

[0040] In the coil unit 10, the multiple coils 4U, 4V, and 4W are arranged at substantially constant intervals. Specifically, the distance between the centers of two adjacent coils of different phases in the direction of movement (for example, the leftmost U-phase coil 4U and the V-phase coil 4V to its right in Figure 5A) is 240 degrees when converted to the electrical angle of a three-phase AC.

[0041] In the embodiment shown in Figure 5B, the single coil unit 10 in Figure 5A is divided into two coil units 10A and 10B. It is practically difficult to arrange these two coil units 10A and 10B, or the coils 4 at both ends thereof, while maintaining the constant coil spacing (240 degrees) mentioned above. Specifically, in Figure 5A, the distance between the centers of the sixth W-phase coil 4W from the left and the seventh U-phase coil 4U was 240 degrees, but in Figure 5B, there is a non-negligible gap between adjacent coil units 10A and 10B, making it practically difficult to arrange the rightmost W-phase coil 4W in the first coil unit 10A and the leftmost U-phase coil 4U' in the second coil unit 10B at a center-to-center distance of 240 degrees.

[0042] In this embodiment, the gap between adjacent coil units 10A and 10B is to be effectively utilized. Specifically, as shown in Figure 5B, for two adjacent coil units 10A and 10B in the direction of movement, an adjustment interval of 180 degrees, converted to the electrical angle of the three-phase AC as the driving current, is added to the distance between the coils located at their opposing ends (in the example in Figure 5B, the W-phase coil 4W at the right end of the first coil unit 10A and the U-phase coil 4U' at the left end of the second coil unit 10B).

[0043] Specifically, since it is difficult to maintain a constant distance of 240 degrees between the centers of the rightmost W-phase coil 4W in the first coil unit 10A and the leftmost U-phase coil 4U' in the second coil unit 10B, as in Figure 5A, an adjustment interval of 180 degrees is added to this constant interval in the example of Figure 5B. Therefore, the distance or interval between the centers of the rightmost W-phase coil 4W in the first coil unit 10A and the leftmost U-phase coil 4U' in the second coil unit 10B is 420 degrees. Alternatively, the leftmost U-phase coil 4U' in the second coil unit 10B in Figure 5B may be interpreted as the seventh U-phase coil 4U from the left in Figure 5A shifted by an adjustment interval of 180 degrees.

[0044] In the coil arrangement described above, the direction of current flowing through the same phase is reversed in the first coil unit 10A and the second coil unit 10B. Specifically, as schematically shown in Figure 5B, the direction of the U-phase current flowing through the U-phase coil 4U′ in the second coil unit 10B is reversed from the direction of the U-phase current flowing through the U-phase coil 4U in the first coil unit 10A, the direction of the V-phase current flowing through the V-phase coil 4V′ in the second coil unit 10B is reversed from the direction of the V-phase current flowing through the V-phase coil 4V in the first coil unit 10A, and the direction of the W-phase current flowing through the W-phase coil 4W′ in the second coil unit 10B is reversed from the direction of the W-phase current flowing through the W-phase coil 4W in the first coil unit 10A.

[0045] For example, by reversing the winding direction of the coils 4 in two adjacent coil units 10A and 10B in the direction of movement (for example, winding one clockwise and the other counterclockwise), the direction of the current in each phase can be easily reversed as described above. In this case, it is not necessary to apply different drive currents to each coil unit 10A and 10B, making it simpler. However, it is also possible to keep the winding direction of the coils 4 in the two coil units 10A and 10B the same and change the direction of the drive current applied to them.

[0046] As described above, according to this embodiment, by appropriately adjusting the spacing between the coil units 10A and 10B and the direction of the drive current flowing through each, continuity in the driving of the movable element 20 spanning the two coil units 10A and 10B can be easily achieved.

[0047] The present disclosure has been described above based on embodiments. Various modifications are possible for each component and each combination of processes in the exemplary embodiments, and it will be obvious to those skilled in the art that such modifications are included in the scope of the present disclosure.

[0048] The configuration, operation, and function of each device and method described in the embodiments can be realized by hardware resources or software resources, or by the cooperation of hardware resources and software resources. Hardware resources include, for example, processors, ROMs, RAMs, and various integrated circuits. Software resources include, for example, operating systems and application programs. [Explanation of Symbols]

[0049] 2 armatures, 2X linear motors, 2Y linear motors, 3 stators, 4 coils, 6 permanent magnets, 10 coil units, 20 movable parts, 100 stage devices, 120 Y-stages, 130 X-stages.

Claims

1. A movable element equipped with a magnetic circuit, A stator comprising a plurality of coils arranged along the direction of movement of the movable element, which exerts a magnetic driving force on the magnetic circuit along the direction of movement in accordance with the driving current flowing through the plurality of coils, A linear motor equipped with, The aforementioned multiple coils are divided and mounted into multiple coil units, which are fewer than the total number of coils. In each of the above coil units, the plurality of coils are arranged at substantially constant intervals. For two adjacent coil units in the aforementioned direction of movement, the distance between the coils located at their opposing ends is obtained by adding an adjustment interval of 180 degrees, calculated as the electrical angle of the drive current, to the aforementioned fixed distance. Linear motor.

2. The linear motor according to claim 1, wherein the winding directions of the coils in two adjacent coil units are opposite to each other in the direction of movement.

3. The plurality of coils are a group of three-phase coils comprising a U-phase coil, a V-phase coil, and a W-phase coil through which the three-phase alternating current as the drive current flows. Each of the coil units comprises an integer number of coils that constitute the three-phase coils, which are multiples of 3. A linear motor according to claim 1 or 2.

4. The linear motor according to claim 1 or 2, wherein the constant interval is 240 degrees when converted to the electrical angle of the drive current.

5. A positioning device powered by a linear motor as described in claim 1 or 2.

6. A processing apparatus for processing an object to be processed that is positioned by the positioning device described in claim 5.

7. A device manufacturing method for manufacturing a device through processing of a workpiece using the processing apparatus described in claim 6.

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