Power supply device

Abstract

Even when incorporating a hydrostatic fluid bearing as a guide mechanism to achieve high-precision positioning, the thick, highly flexible power supply cable required to supply the necessary current to the movable parts of the moving stage will not degrade the positioning accuracy of the moving stage mechanism or increase the power consumption of the drive mechanism. [Solution] A power supply device for supplying power from a fixed stage portion to a movable stage portion of a stage device, wherein the movable stage portion is floatingly supported by a hydrostatic fluid bearing on the fixed stage portion, the hydrostatic fluid bearing has a hydrostatic pad provided on the movable stage portion and a hydrostatic guide provided on the fixed stage portion, electrodes are provided on each surface of the hydrostatic pad and the hydrostatic guide, and the power supply device is characterized in that an electric field coupling type wireless power supply is performed between the respective surfaces of the hydrostatic pad and the hydrostatic guide.

Description

Technical Field

[0001] The present invention relates to a power supply device, for example, a power supply device used in a stage device such as a processing device having a stage mechanism using a hydrostatic fluid bearing, a semiconductor exposure device, or an assembly device.

Background Art

[0002] Conventionally, a power supply device for supplying power to a movable part of a moving stage in a stage device such as a processing device, a semiconductor exposure device, or an assembly device having a high-precision moving stage drive mechanism is known. In such a power supply device, relatively large power is supplied to load such as a motor of the stage movable part. However, in order to supply large power required by the drive motor of the stage movable part, a large-capacity power supply cable is required between the stage movable part and the stage fixed part, and the large-capacity power supply cable tends to be thick, heavy, and rigid. The moving stage mechanism moves while pushing and pulling this power supply cable. For this reason, there have been problems such as an increase in the power consumption of the motor due to the reaction force caused by the bending resistance of the power supply cable, and the vibration of the cable being applied to the moving stage mechanism and the positioning performance of the moving stage mechanism deteriorating.

[0003] In view of the above problems, conventionally, as shown in Patent Document 1, a configuration in which a second moving stage mechanism that moves in parallel with a first moving stage mechanism that requires accuracy is provided is known.

[0004] In Patent Document 1, a power supply cable supplied from a fixed part to the first moving stage mechanism is relayed by the second stage mechanism. The second stage mechanism is driven in synchronization with the first stage mechanism. In such an operation, in the power supply cable provided between the first and second moving stages, stress such as bending resistance does not occur, and it does not affect the original operation accuracy of the stage device.

[0005] In particular, in the configuration of Patent Document 1, the second stage mechanism absorbs stress such as the bending resistance of the power supply cable between the fixed part and the first moving stage, so that stress such as the bending resistance of the power supply cable does not act on the first moving stage. Therefore, the power consumption that would otherwise be required to counteract the bending resistance of the power supply cable in the first moving stage mechanism can be reduced. In addition, vibrations of the power supply cable, which are a factor in deteriorating positioning accuracy, can be eliminated. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 8-233964 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] However, the configuration in Patent Document 1 requires the addition of a second moving stage mechanism, which tends to increase the overall size and weight of the equipment. Furthermore, power is required to drive the second moving stage mechanism, which tends to increase the power consumption of the equipment.

[0008] Furthermore, while the installation of a second moving stage mechanism reduces the bending resistance of the power supply cable, vibrations generated in the power supply cable are transmitted to the first moving stage. In other words, vibrations, including those generated by the second moving stage mechanism, are transmitted to the first moving stage via the power supply cable connecting the first and second moving stage mechanisms. Therefore, there was a problem in that it was not possible to completely prevent this from becoming a factor in the deterioration of the positioning accuracy of stage equipment such as processing equipment, semiconductor exposure equipment, or assembly equipment. [Means for solving the problem]

[0009] A first aspect of the present invention is a power supply device for supplying power from a fixed stage portion to a movable stage portion of a stage apparatus, wherein the movable stage portion is floatingly supported by a hydrostatic fluid bearing on the fixed stage portion, the hydrostatic fluid bearing has a hydrostatic pad provided on the movable stage portion and a hydrostatic guide provided on the fixed stage portion, electrodes are provided on each surface of the hydrostatic pad and the hydrostatic guide, and wireless power supply using an electric field coupling method is performed between the respective surfaces of the hydrostatic pad and the hydrostatic guide. [Effects of the Invention]

[0010] According to the present invention, since wireless power supply using an electric field coupling method is performed to the movable part of the stage, a second moving stage mechanism as in the conventional method is not required, reducing the power consumption of the equipment, making the entire stage device smaller and lighter, and preventing deterioration of the positioning accuracy of the stage device. [Brief explanation of the drawing]

[0011] [Figure 1] This is an explanatory diagram showing the configuration of a first embodiment of the stage device according to the present invention. [Figure 2] This is an explanatory diagram showing the configuration of a second embodiment of the stage device according to the present invention. [Figure 3] This is an explanatory diagram showing the configuration of a third embodiment of the stage device according to the present invention. [Figure 4] This is an explanatory diagram showing the configuration of a fourth embodiment of the stage device according to the present invention. [Figure 5] Figure 5 is a flowchart illustrating the control procedure in the configuration shown in Figure 4. [Modes for carrying out the invention]

[0012] Embodiments of the present invention will be described below with reference to the attached drawings. In the following embodiments, the same or equivalent components will be denoted by the same reference numerals, and redundant descriptions will be omitted.

[0013] [Embodiment 1] The moving stage mechanism of the stage apparatus in Figure 1 comprises a movable stage section 102 and a fixed stage section 101. The movable stage section 102 is driven along the y-direction (104) via a linear motor having a motor coil 115 and a motor magnet 116. The movable stage section 102 is equipped with a tool spindle 119, and a cutting tool 120 supported by the tool spindle 119 is driven at a predetermined position along the y-direction (104) to perform machining of an object (not shown).

[0014] The support structure of the movable stage part 102 by the fixed stage part 101 is arbitrary, but in the configuration of Figure 1, the movable stage part 102 is supported by compressed air supplied from the fixed stage part 101, for example, from the static pressure pads 106a to 106d, as described later.

[0015] In the configuration shown in Figure 1, the motor coil 115 is driven by an alternating current wirelessly supplied from a high-frequency AC power supply 109a as described below, thereby controlling the movement of the stage movable part 102 along the y-direction (104). For convenience, the flow of the alternating current from the high-frequency AC power supply 109a will be explained in a clockwise direction in the figure. The high-frequency AC power supply 109a is connected to the conductor static pressure guide 107a via wiring 110a and 110b and an adjustment impedance circuit 111a. The static pressure guide 107a faces the static pressure pad 106a with a guide gap 108a. The conductor static pressure guide 107a and the static pressure pad 106a function as electrodes, and the air in the guide gap 108a acts as a dielectric to form an electric field-coupled wireless power supply device. The conductor static pressure guide 107a and the static pressure pad 106a act electrically as capacitors, transmitting the high-frequency alternating current from the high-frequency AC power supply 109a.

[0016] The static pressure pad 106a is connected to the rectifier circuit 112a within the movable stage section 102 via wirings 110c and 110d and an adjustment impedance circuit 111b. The other electrode of the rectifier circuit 112a is connected to the conductive static pressure pad 106b via wirings 110e and 110f and an adjustment impedance circuit 111c. The static pressure pad 106b, together with the opposing static pressure guide 107b, forms an electrode and constitutes an electric field-coupled wireless power supply device, which functions electrically as a capacitor. Furthermore, in the fixed stage section 101, the static pressure guide 107b is connected to the high-frequency AC power supply 109a via wirings 110g and 110h and an adjustment impedance circuit 111d.

[0017] Meanwhile, the DC current rectified and converted to DC in the rectifier circuit 112a is connected to the input terminal of the battery 113a and stored in the battery 113a. The output terminal of the battery 113a is connected to the current amplifier 114a. The current amplifier 114a supplies a commanded current to the motor coil 115 of the linear motor in response to a command from a control circuit (not shown). When current flows through the motor coil 115, thrust is generated by interaction with the motor magnet 116, moving the movable stage part 102 to the target position in the y-direction (104). The position information of the movable stage part 102 is detected by the encoder head 117 via the change in relative position with the encoder scale 118, and transmitted wirelessly from the transmitter in the encoder head to a control circuit (not shown). This control circuit performs control calculations from the difference between the position detected by the encoder head 117 and the target position and wirelessly instructs the current amplifier 114a on the command value of the current. The detection method of the encoder head 117 can be any method, such as optical or magnetic.

[0018] Note that Figure 1 shows a configuration in which the control circuit (not shown), encoder head 117, and current amplifier are connected wirelessly. However, even if these are connected by wire, the wiring required to connect to the encoder head 117 and current amplifier 114a is very light and thin compared to the power cable for driving, so these wires may also be connected by wire.

[0019] In addition, in this embodiment, the tool spindle 119 and the cutting tool 120 are driven by wireless power supply from the high-frequency AC power supply 109b. The high-frequency AC power supply 109b is connected to the static pressure guide 107c via the wirings 110g and 110h and the adjustment impedance circuit 111e. The static pressure guide 107c and the static pressure pad 106c constitute a wireless power supply device of the electric field coupling type using the air in the guide gap 108c as a dielectric. On the other hand, in the stage movable part 102, the static pressure pad 106c is connected to the rectifier circuit 112b via the wirings 110k and 110l and the adjustment impedance circuit 111f. The other electrode of the rectifier circuit 112b is connected to the static pressure pad 106d via the wirings 110m and 110n and the adjustment impedance circuit 111g. The static pressure pad 106d and the facing static pressure guide 107d constitute an electrode and a wireless power supply device of the electric field coupling type, and function as a capacitor electrically. Further, in the stage fixed part 101, the static pressure guide 107d is connected to the high-frequency AC power supply 109b via the wirings 110o and 110p and the adjustment impedance circuit 111h.

[0020] Next, the static pressure fluid bearing mechanism of the moving stage mechanism, which is the mechanical part of FIG. 1, will be described. The moving stage mechanism includes a stage movable part 102 and a stage fixed part 101. The material of the base material parts of the stage movable part 102 and the stage fixed part 101 is ceramic unless otherwise specified. Here, the ceramic used for the stage movable part 102 and the stage fixed part 101 is an insulator and there is no electrical conduction.

[0021] In addition, in the stage device of this embodiment, the moving stage mechanism includes a static pressure fluid bearing mechanism including static pressure pads 106a to 106d and static pressure guides 107a to 107d. This static pressure fluid bearing mechanism restrains and holds movements other than the movement in the y direction (104), which is the movable direction of the stage movable part 102.

[0022] Multiple hydrostatic pads 106a to 106d (hydrostatic pad section) and hydrostatic guides 107a to 107d (hydrostatic guide section), which constitute the hydrostatic fluid bearing mechanism that makes up the hydrostatic guide mechanism, are held relative to each other with a guide gap 108a to 108d at a constant distance. A tube piping (not shown) is connected to the hydrostatic pads 106a to 106d, and compressed air is supplied through this tube piping. The hydrostatic pads 106a to 106d discharge the compressed air supplied to the guide gap 108a to 108d between them and the hydrostatic guides 107a to 107d. By maintaining a high pressure in the guide gap 108a to 108d, the hydrostatic pads 106a to 106d float away from the hydrostatic guides 107a to 107d, maintaining the guide gap 108a to 108d at a constant distance, and floating the movable stage section 102.

[0023] Here, in Figure 1, the size and arrangement of the hydrostatic pads 106a and 106b and the hydrostatic guides 107a and 107b in the y-direction (104), which is perpendicular to the plane of the paper (not shown), will be explained. The area of ​​the hydrostatic pads 106a and 106b is approximately 50 mm, and multiple hydrostatic pads 106a and 106b are arranged in a row to match the length of the movable stage part 102 in the y-direction (104). Furthermore, in the depth direction of the hydrostatic pads 106a, magnets are arranged in the same row (not shown) in a row of multiple hydrostatic pads 106a arranged in the y-direction (104). These magnets are fixed to the movable stage part 102 between the rows of hydrostatic pads 106a. The magnets fixed to the movable stage part 102 generate an attractive force on the hydrostatic guides 107a and 107b, and apply magnetic pressure to the hydrostatic fluid bearing mechanism. Magnets are similarly arranged in the row of static pressure pads 106b. On the other hand, the length of the static pressure guides 107a and 107b has a depth approximately equal to the sum of the length of the stage and the movable stroke of the stage.

[0024] In this configuration, when connecting wiring 110e and 110f to the static pressure pads 106a and 106b described above, all of the multiple static pressure pads 106a and 106b arranged in the depth direction are connected. In some cases, it is not necessary to connect all of the static pressure pads 106a and 106b and wiring 110e and 110f, but the number of connections can be selected, however, at least one connection is required.

[0025] Here, we will explain the distance of the guide gaps 108a to 108d. The distance of the guide gaps 108a to 108d can be predetermined in the bearing design, ranging from a few micrometers to 20 micrometers, assuming air as the fluid. In this embodiment, air is used as the fluid for floating support of the movable stage part 102, but it is conceivable to use oil or other fluids. If oil is used as the fluid for floating support of the movable stage part 102, the moving stage mechanism should be designed so that the gap is between 10 and 100 micrometers, and the pressure of the supplied compressed air should also be determined.

[0026] The guide gaps 108a to 108d vary slightly depending on the position in the direction of movement of the stage movable part 102, due to the manufacturing and assembly accuracy of the surfaces (guide surfaces of the hydrostatic guides) of the hydrostatic guides 107a to 107d. In addition, the gaps may fluctuate due to disturbances such as fluctuations in the fluid pressure supplied to the hydrostatic pads 106a to 106d and device vibrations.

[0027] However, in high-precision devices requiring a hydrostatic fluid bearing mechanism, maintaining high performance of the moving stage mechanism requires strictly controlling fluctuating factors such as pressure fluctuations of the compressed air supplied to the hydrostatic pads 106a to 106d. This suppresses fluctuations in drive accuracy. As a result, while there are reproducible changes of less than a few μm in the distance of the guide gaps 108a to 108d depending on the positional difference of the stage movable part 102 in the y-direction (104), fluctuations in vibration factors are further reduced to a fraction of that. In electric field coupled wireless power supply devices, the distance between electrodes leads to changes in the characteristics of the power supply circuit. The guide gaps 108a and 108b, which are the distances between electrodes, can be made significantly narrower than the gaps in other general wireless power supply devices.

[0028] One advantage of wireless power transfer as in this embodiment, which allows for a reduced spatial distance for wireless connection, is that, in the case of electric field coupling, the voltage and frequency of the supplied AC power can be kept low. The high-frequency AC power supplies 109a and 109b used in wireless power transfer are, as their names suggest, high-frequency AC power supplies ranging from tens of kHz to hundreds of kHz. With current technology, it is possible to increase the frequency of the high-frequency AC power supplies 109a and 109b to the MHz order and to increase the voltage. However, increasing the frequency and voltage may generate leakage current, so keeping it within a few hundred volts at the kHz order is desirable from an efficiency standpoint.

[0029] The selection of the frequency is fundamentally based on the frequency at which resonance occurs in the impedance of the wireless power transfer section. Supplying power at the resonant frequency minimizes the circuit impedance, leading to improved power transfer efficiency. To lower the resonant frequency, it is effective to increase the capacitance of the electric field-coupled wireless power transfer section, which acts as the capacitor. If the same voltage is applied, a wider air gap (the distance between electrodes) weakens the electric field generated between the electrodes. In other words, a small air gap results in a capacitor with small capacitance. The resonant frequency can be adjusted by incorporating adjustment impedance circuits 111a to 111h into the circuit. However, using static pressure pads 106a and 106b and static pressure guides 107a and 107b as electrodes offers a significant advantage in that the distance between electrodes can be narrowed to the order of 10 μm in its basic state.

[0030] Furthermore, in Figure 1, a wireless power supply device integrated with a hydrostatic fluid bearing is also used to supply power for driving the tool spindle 119 and the cutting tool 120. The difference from wireless power supply to the motor coil 115 is that the path has been changed to use different hydrostatic pads 106c, 106d and hydrostatic guides 107c, d for the hydrostatic fluid bearing mechanism that is supplied. The circuit configuration is the same as described above, except that the destination of the power supply is different from that of the motor coil 115 of the stage movable part 102.

[0031] Here, we will add an explanation regarding the power supply wiring and tubing to the encoder head 117 and other components. We will also add an explanation regarding the connection of various wireless control signal lines. Regarding these signal lines, even if a wired connection is chosen instead of wireless communication, thin wiring is sufficient, so the impact is much smaller compared to the power supply cables for stage drive, which have been a problem in the past. The same applies to power supply to equipment other than drive equipment; for power supply, the wireless power supply device of the present invention may be incorporated into the hydrostatic fluid bearing mechanism as needed to supply power to various devices. Alternatively, the power supplied wirelessly as drive power in the present invention may be branched and used. Next, we will explain the handling of tubing.

[0032] In contrast to the conventional power supply cables used for stage drive, which have been problematic, the fluid-carrying tubes do not have a thick, bundled metal core, making them lighter and easier to bend. Therefore, their impact on the positioning accuracy of the moving stage is extremely small. In this embodiment, air is used as the fluid in the hydrostatic fluid bearing, but oil can also be used as the fluid supplied to the hydrostatic fluid bearing. When oil is used as the fluid, the gap between the hydrostatic pad and the hydrostatic guide, which is the fixed part, is about 20 μm. However, the gap can be determined from a range of several tens of μm to several tens of μm to become a design value, which is an arbitrary predetermined gap based on the rigidity required for the guide. When oil is used as the fluid, the hydrostatic pad is not porous and has a pocket shape or groove shape on the surface that faces or is directly opposite the surface of the hydrostatic guide. Therefore, the aforementioned guide gaps 108a,b are the minimum gaps between the surfaces of the hydrostatic pads 106a,b and the surfaces of the hydrostatic guides 107a,107b, and in some parts, such as the pocket-shaped parts, the gap is close to a millimeter.

[0033] According to this embodiment, by making the power supply to the movable parts of the stage device wireless, the installation of power supply cables is unnecessary, and the second moving stage mechanism as in the conventional method is also unnecessary, allowing the stage device to be made smaller and lighter. Furthermore, the omission of the second moving stage mechanism reduces waste such as power consumption. In addition, by making the power supply wireless, cables that supply power to the movable parts of the stage device are no longer needed. Therefore, vibrations are not transmitted to the movable parts via the power supply cable as in the conventional method, and the factor that reduces positioning accuracy caused by the power supply cable can be eliminated.

[0034] [Embodiment 2] In the above embodiment 1, the configuration in which the movable stage part 102 moves linearly relative to the fixed stage part 101, or moves linearly, was shown. In this embodiment, an example is given in which the movable stage part consists of a rotating stage movable part 202 that rotates relative to the rotating stage fixed part 201.

[0035] Figure 2 shows the configuration of the stage device of this second embodiment. First, the mechanical configuration of the rotary stage in Figure 2 will be explained. The rotary stage movable part 202 is movably supported around the rotational axis 209, which is shown in the center of the figure by thick and dashed lines. In order to restrain the rotary stage movable part 202 in the thrust direction (z-axis 105), two thrust hydrostatic guides 207a and 207b are positioned so as to sandwich the rotary stage movable part 202.

[0036] Two thrust hydrostatic pads 206a and 206b are positioned on the rotating stage fixed part 201, facing each other, the two thrust hydrostatic guides 207a and 207b. The thrust hydrostatic pads 206a and 206b and the thrust hydrostatic guides 207a and 207b form a ring shape around the rotational axis. In the radial direction (radial direction around the rotational axis 209), a radial hydrostatic guide 204 is positioned on the rotating stage movable part 202, which rotates so as to face or be directly opposite to the radial hydrostatic pad 203 positioned on the rotating stage fixed part 201.

[0037] The pad surfaces of the thrust hydrostatic pads 206a and 206b are made of porous graphite, which is a conductor, and the thrust hydrostatic guides 207a and 207b are also made of the same conductive material. In addition, the base members of the movable part 202 of the rotating stage and the fixed part 201 of the rotating stage are made of ceramics, which is an insulator. With this configuration, the thrust hydrostatic pads 206a and 206b are insulated from the fixed part 201 of the rotating stage, and the thrust hydrostatic guides 207a and 207b are insulated from the movable part 202 of the rotating stage.

[0038] Next, the wireless power supply unit (wireless power supply means) of the hydrostatic fluid bearing mechanism shown in Figure 2 will be described. The disc-shaped thrust hydrostatic pads 206a and 206b provided on the rotating stage fixed part 201 are conductors using porous graphite on the pad surface and function as one electrode of the electric field coupled type wireless power supply unit. The thrust hydrostatic pads 206a and 206b constitute the first pad-side electrode and the second pad-side electrode, respectively. On the other hand, the disc-shaped thrust hydrostatic guides 207a and 207b installed on the rotating stage movable part 202 are made of conductive steel or equivalent graphite and function as the other electrode of the electric field coupled type wireless power supply unit. That is, the thrust hydrostatic guides 207a and 207b constitute the first guide-side electrode and the second guide-side electrode, respectively. There are bearing gaps 208a and 208b between the thrust hydrostatic guides 207a and 207b and the thrust hydrostatic pads 206a and 206b, respectively. The spaces in the bearing gaps 208a and 208b are filled with compressed air discharged from the thrust hydrostatic pads 206a and 206b. The air in this space acts as a dielectric, with the thrust hydrostatic guides 207a and 207b and the thrust hydrostatic pads 206a and 206b acting as electrodes, and together functioning as a capacitor in the electric field-coupled wireless power supply unit. That is, the first pad-side electrode and the first guide-side electrode constitute the first wireless power supply means, and the second pad-side electrode and the second guide-side electrode constitute the second wireless power supply means. These wireless power supply means supply power without contact. Figure 2 shows a cross-section of the cylindrical structure. Furthermore, for simplification, the symbols for thrust hydrostatic guides 207a, 207b and thrust hydrostatic pads 206a, 206b are omitted from the illustration on the right side of Figure 2.

[0039] Here, the connections of each wiring will be explained clockwise starting from the high-frequency AC power supply 109. The high-frequency AC power supply 109 is connected to the thrust static pressure pad 206a via wiring 110a, 110b and an adjustment impedance circuit 111a. The thrust static pressure pad 206a, bearing gap 208a, and thrust static pressure guide 207a are the first wireless power supply section of the electric field coupling method and act electrically as capacitors. The thrust static pressure guide 207a is connected to the rectifier circuit 112 via wiring 110c, 110d, and an adjustment impedance circuit 111b. The rectifier circuit 112 is connected to the thrust static pressure guide 207b via wiring 110e, 110f, and an adjustment impedance circuit 111c. The thrust static pressure pad 206b, bearing gap 208b, and thrust static pressure guide 207b are the second wireless power supply section of the electric field coupling method and act electrically as capacitors, transmitting AC current. The thrust static pressure pad 206b is connected to the high-frequency AC power supply 109 via wiring 110g, 110h and an adjustment impedance circuit 111d.

[0040] Meanwhile, the DC current rectified and converted in the rectifier circuit 112 is connected to the input terminal of the battery 113 and stored in the battery 113. The output terminal of the battery 113 is connected to the current amplifier 114. The current amplifier 114 supplies a current specified by a command to the rotary motor coil 215 of the rotary motor according to a command from a control circuit (not shown). This rotary motor coil 215 generates thrust through interaction with the rotary motor magnet 216, generating a driving force that rotates the movable part 202 of the rotary stage around the rotation axis center (209).

[0041] In this embodiment, the hydrostatic fluid bearing that restrains the thrust direction is used as the electrode part of the electric field coupling method of the wireless power supply device, but a hydrostatic fluid bearing that restrains the radial direction may also be used.

[0042] As in this embodiment, even in a configuration where the movable stage part is rotationally driven, wireless power supply to the movable stage part eliminates the need for power supply cables and the need for a second moving stage mechanism as in the past, allowing for a smaller and lighter stage device. Furthermore, the omission of the second moving stage mechanism reduces waste such as power consumption. In addition, wireless power supply eliminates the need for cables to supply power to the movable stage part of the stage device. Therefore, vibrations are not transmitted to the movable part via power supply cables as in the past, eliminating the factor that reduces positioning accuracy caused by power supply cables.

[0043] [Embodiment 3] Figure 1 illustrates the power supply to the linear motor that drives the moving stage as an example of the power supplied to the movable part of the stage. However, in some machining centers, in addition to the tool spindle shaft, another moving stage mechanism may be mounted on the movable part of the moving stage mechanism, resulting in a multi-stage system with two or three stages. In this embodiment 3, such a multi-stage configuration is illustrated as an example.

[0044] In many cases, when configuring a multi-stage system, a rotating stage is installed, or the upper stages of the multi-stage system are designed with a moving stage mechanism whose direction of movement is perpendicular to that of the lower stages. However, even when the moving stage mechanism is multi-stage, a means of supplying power to the drive source used in the upper moving stage mechanism is required. This embodiment 3 describes the configuration when the moving stage mechanism is multi-stage in this way.

[0045] Figure 3 shows the configuration of the stage device of this third embodiment. In Figure 3, a configuration is shown in which an upper stage mechanism is mounted on the stage movable part 102a of the moving stage mechanism. When mounting in multiple stages in this way, the upper and lower drive directions are usually arranged to be perpendicular to each other. In order to simplify the explanation of how to connect the wireless power supply device, both the upper and lower stage mechanisms are conveniently shown to move in the same direction perpendicular to the plane of the paper, the y direction (104). Since the movement direction of the lower stage in Figure 3 is the y direction (104), the movement direction of the upper stage movable part 102b should ideally be the x direction (103), which is perpendicular to the y direction (104). However, in Figure 3, for the sake of illustration, the movement direction of the upper stage movable part 102b is taken to be the y direction (104).

[0046] In this configuration, power is supplied to the drive sources of both the upper and lower moving stages from the high-frequency AC power supply 109b of the lower stage's fixed section 101a. Therefore, the power supplied to the stage movable section 102a of the upper moving stage mechanism passes through the hydrostatic pads 106c, 106d and hydrostatic guides 107c, d that constitute the hydrostatic fluid bearing mechanism of the lower moving stage mechanism. This power is then supplied to the stage movable section 102b of the upper moving stage mechanism via the hydrostatic pads 106e, f and hydrostatic guides 107e, 107f that constitute the hydrostatic fluid bearing of the upper moving stage mechanism. Finally, it is supplied to the motor coil 115b of the upper stage. Alternatively, a configuration may be used in which the power supplied using the power supply mechanism described in this embodiment is branched and supplied from the lower stage's movable section 102a to the fixed section 101b of the upper moving stage mechanism.

[0047] Even in a multi-stage stage system like this embodiment, wireless power supply to the movable parts of the stage eliminates the need for power supply cables and the need for a second moving stage mechanism, allowing for a smaller and lighter stage system. Furthermore, the omission of the second moving stage mechanism reduces wasted power consumption. In addition, wireless power supply eliminates the need for cables to supply power to the movable parts of the stage system. As a result, vibrations are not transmitted to the movable parts via power supply cables, eliminating the factor that reduces positioning accuracy caused by power supply cables.

[0048] [Embodiment 4] Figure 4 shows the configuration of the stage device 401 of this embodiment 4. Figure 5 shows the control procedure executed by the control circuit 403 of the stage device 401. The control circuit 403 consists of a CPU, ROM, RAM, etc., and the control procedure in Figure 5 can be stored in the ROM as a CPU program, for example.

[0049] In Figure 4, the stage device 401 includes, for example, the hydrostatic fluid bearing integrated wireless power supply device shown in Embodiment 1. However, the stage device 401 may have the configuration of the stage device in Embodiments 2 or 3. The control circuit 403 controls the stage device 401. For example, the control circuit 403 controls the positioning of the movable stage part of the stage device 401 in accordance with the progress of the machining operation of the stage device 401. At this time, if the pressure of the compressed air supplied to the hydrostatic fluid bearing fluctuates, and in the worst case the supply of compressed air stops, the hydrostatic fluid bearing part of the stage device 401 may seat. If the movable stage part of the stage device 401 is moving in this state, the tool, workpiece, and hydrostatic fluid bearing mechanism may be damaged during machining.

[0050] To prevent this damage, the movable part of the stage is supported by a pressure sensor 405, which is a pressure detection means for detecting the pressure of compressed air supplied to the stage device 401 (step S1 in Figure 5). If the pressure falls below a specified value, the control circuit 403 detects this (step S2 in Figure 5). The pressure sensor 405 is attached to the tube piping 405a and 405b, for example, as shown in Figure 4. If the pressure detected by the pressure sensor 405 falls below a specified value (steps S2 to S3 in Figure 5), an error signal is sent to the stage device 401 to perform an emergency stop operation. This emergency stop operation is performed using power stored in a battery (for example, 113 in Figure 1), which is a power storage means, if necessary. In this emergency stop operation (step S4 in Figure 5), the control circuit 403 transmits an error signal to a current amplifier (e.g., 114 in Figure 1) of the movable stage part of the stage device 401 (not shown) via the wireless transceiver 404 and transducer 404a. Upon receiving this error signal, the stage device 401 slows down and stops the movable stage part. It also transmits a control command to stop the output of the high-frequency AC power supply (not shown) of the stage device 401. By performing such control, damage to the movable stage part of the stage device 401, or to the workpiece or tool being processed (120 in Figure 1), can be prevented. The control circuit 403 can also control the normal operation of the stage device via the wireless transceiver 404 and transducer 404a.

[0051] [Embodiment 5] This embodiment 5 corresponds to a modification of embodiments 1 to 4, but the configuration described in this embodiment 5 is a countermeasure when the material of the opposing surfaces of the hydrostatic pads and hydrostatic guides, for example, hydrostatic pads 106c and 106d and hydrostatic guides 107e and 107f in Figure 1, is made of an insulator.

[0052] When the material of the static pressure pad is an insulator, a conductive electrode is installed on the back surface of the static pressure pad that faces the surface of the static pressure guide. The configuration of the present invention can also be applied when it is necessary to use an insulator for the static pressure pad using this method.

[0053] The hydrostatic pad is used as an electrode, and the space between it and the electrode installed on the surface of the hydrostatic guide (hydrostatic guide surface) is formed as a capacitor, creating a hydrostatic fluid bearing integrated wireless power supply device. In this case, it is preferable to select a material for the insulating part of the hydrostatic pad that is several mm thick and has a relative permittivity close to 1. By increasing the distance between the electrodes, the effect on the capacitance of the floating gap portion of the hydrostatic pad when the space between the electrodes is used as a capacitor can be reduced. With this configuration for the movable part of the stage, even if the gap between the hydrostatic pad and the hydrostatic guide surface changes, the influence of impedance changes in the electrical circuit of the electric field junction type wireless power supply device can be reduced. Thus, there are advantages to having an insulating part facing the guide gap of the hydrostatic pad and hydrostatic guide.

[0054] For example, in a capacitor formed between the surface of a hydrostatic pad and a hydrostatic guide, the capacitance of the insulating portion of the hydrostatic guide is set to be a large ratio to the capacitance of the bearing gap. In this case, even if the bearing gap changes by 10 μm, for example by several μm, it is possible to make the change in the capacitance of the part that functions as a capacitor less than 1%. Therefore, without adjusting the impedance for adjustment, the adjustment of the coil portion and the resonant frequency is minimized, and there is an effect of not causing a change in the power supply efficiency of the wireless power supply device. In this way, even when the surface of the hydrostatic pad or hydrostatic guide that is in contact with the guide gap on the surface facing it must be an insulator, the present invention can be carried out by incorporating a conductor into the hydrostatic pad or hydrostatic guide, treating the hydrostatic pad or hydrostatic guide as an electrode.

[0055] [Possibility of other embodiments] The stage mechanism described in Embodiments 1 to 5 above can be installed in devices such as processing equipment, measuring equipment, and semiconductor manufacturing equipment. Specifically, a device can be configured comprising a shaft as a first component, a fluid bearing movable relative to the shaft, and a second component supported by the fluid bearing. In this case, the second component can be various parts such as a processing tool, a measuring instrument (probe, etc.), or a workpiece holder. Then, an article (workpiece) can be manufactured using these devices.

[0056] This specification discloses at least the following: [Item 1] In a power supply device that supplies power from the fixed stage section to the movable stage section of a stage structure, The movable part of the stage is floatingly supported by a hydrostatic fluid bearing on the fixed part of the stage. The hydrostatic fluid bearing comprises a hydrostatic pad provided on the movable part of the stage and a hydrostatic guide provided on the fixed part of the stage. Each surface of the hydrostatic pad and the hydrostatic guide is provided with electrodes. A power supply device characterized by performing electric field coupling type wireless power supply between the respective surfaces of the static pressure pad and the static pressure guide. [Matter 2] The movable part of the stage moves relative to the fixed part of the stage by linear or rotational motion, and performs electric field coupling wireless power supply between the surfaces of the static pressure pad and the static pressure guide. A power supply device as described in item 1, characterized by the features described above. [Matter 3] The material of the portion of the hydrostatic pad of the hydrostatic fluid bearing that faces the hydrostatic guide is a conductor, and the conductor provided on the surface of the hydrostatic guide facing the conductor of the hydrostatic pad functions as an electric field-coupled wireless power supply means. A power supply device according to item 1 or item 2, characterized by the above. [Matter 4] The hydrostatic fluid bearing has a hydrostatic pad whose material is conductive in the portion facing the hydrostatic guide, and the hydrostatic pad has a conductive material on the back surface of the surface facing the dielectric material as an electrode of the hydrostatic pad, and the dielectric material of the hydrostatic pad, which is positioned between the electrode of the hydrostatic pad and the electrode provided on the surface of the hydrostatic guide facing it, and the air gap of the hydrostatic fluid bearing functions as an electric field coupling type wireless power supply unit. A power supply device according to any one of items 1 to 3, characterized by the features described above. [Matter 5] The fluid used in the hydrostatic fluid bearing is oil, and the oil discharged from the hydrostatic pad is used as the dielectric for the electric field coupling type wireless power supply unit. A power supply device as described in any one of items 1 to 4, characterized by the above. [Matter 6] The pad surface of the hydrostatic pad of the hydrostatic fluid bearing is made of porous graphite. A power supply device according to any one of items 1 to 5, characterized by the features described herein. [Matter 7] The hydrostatic fluid bearing is provided with a first guide-side electrode that functions as an electrode on the surface of the hydrostatic guide, and when there are multiple hydrostatic pads facing the first guide-side electrode, the first pad-side electrode is provided as an electrode to be installed on at least one of the hydrostatic pads. Furthermore, the first guide-side electrode and the first pad-side electrode function as a first wireless power supply unit that performs a pair of electric field coupling type wireless power supply. The invention provides a second guide-side electrode that does not short-circuit with the first wireless power supply unit, and, in the case where there are multiple static pressure pads facing the second guide-side electrode, the second pad-side electrode is provided as an electrode to be installed on at least one static pressure pad. The second guide-side electrode and the second pad-side electrode function as a second wireless power supply unit that performs a pair of electric field coupling type wireless power supply. Between the first and second wireless power supply units, AC current is supplied wirelessly from the stage fixed unit to the stage movable unit in a non-contact manner. A power supply device according to any one of items 1 to 6, characterized by the features described above. [Matter 8] A pressure detection means for detecting the pressure of the fluid supplied to the hydrostatic fluid bearing, The stage movable part is provided with a power storage means, If the pressure detected by the pressure detection means falls below a preset value, the control circuit of the stage device outputs an error signal to the movable part of the stage device, causing the stage device to perform an emergency stop operation and to stop the wireless power supply. A power supply device according to any one of items 1 to 7, characterized by the features described above. [Industrial applicability]

[0057] The power supply device of the present invention can be used in power supply devices, such as stage devices including processing equipment, semiconductor exposure equipment, or assembly equipment having a stage mechanism using a hydrostatic fluid bearing. [Explanation of symbols]

[0058] 101a, 101b…Stage fixing part 102a, 102b…Stage movable part 103…x direction 104…y direction 105…z direction 106a~106h…Static pressure pad 107a~107h…Static pressure guide 108a~108h…Bearing gap (air gap) 109a, 109b…High frequency AC power supply 110a~110v…Wiring 111a~111s…Adjustable impedance circuit 112a~112c…Rectifier circuit 113a~113c…Battery 114a~114c…Current amplifier 115a, 115b…Linear motor coil 116a, 116b…Linear motor magnet 117a, 117b…Encoder head 118a, 118b…Encoder scale 119…Tool spindle 120…Cutting tool 201…Rotating stage fixed part 202…Stage movable part 203…Radial bearing hydrostatic pad 204…Radial bearing hydrostatic guide 205…Bearing clearance (air gap) 206a~206c…Thrust bearing hydrostatic pad 207a~207c…Thrust hydrostatic guide 208a~208c…Bearing clearance (air gap) 209…Rotation axis center 401…Stage device 402…Control circuit 404…Transmitter / receiver 404a…Transducer 405a,405b…Tube piping 405…Pressure sensor

Claims

1. In a power supply device that supplies power from the fixed stage section to the movable stage section of a stage structure, The movable part of the stage is floatingly supported by a hydrostatic fluid bearing on the fixed part of the stage. The hydrostatic fluid bearing comprises a hydrostatic pad provided on the movable part of the stage and a hydrostatic guide provided on the fixed part of the stage. Each surface of the hydrostatic pad and the hydrostatic guide is provided with electrodes. A power supply device characterized by performing electric field coupling type wireless power supply between the respective surfaces of the static pressure pad and the static pressure guide.

2. The movable part of the stage moves relative to the fixed part of the stage by linear or rotational motion, and performs electric field coupling wireless power supply between the surfaces of the static pressure pad and the static pressure guide. The power supply device according to feature 1.

3. The material of the portion of the hydrostatic pad of the hydrostatic fluid bearing that faces the hydrostatic guide is a conductor, and the conductor provided on the surface of the hydrostatic guide facing the conductor of the hydrostatic pad functions as an electric field-coupled wireless power supply means. The power supply device according to feature 1.

4. The hydrostatic fluid bearing has a hydrostatic pad whose material is conductive in the portion facing the hydrostatic guide, and the hydrostatic pad has a conductive material on the back surface of the surface facing the dielectric material as an electrode of the hydrostatic pad, and the dielectric material of the hydrostatic pad, which is positioned between the electrode of the hydrostatic pad and the electrode provided on the surface of the hydrostatic guide facing it, and the air gap of the hydrostatic fluid bearing functions as an electric field coupling type wireless power supply unit. The power supply device according to feature 1.

5. The fluid used in the hydrostatic fluid bearing is oil, and the oil discharged from the hydrostatic pad is used as the dielectric for the electric field coupling type wireless power supply unit. A power supply device according to any one of claims 1 to 4.

6. The pad surface of the hydrostatic pad of the hydrostatic fluid bearing is made of porous graphite. A power supply device according to any one of claims 1 to 4.

7. The hydrostatic fluid bearing is provided with a first guide-side electrode that functions as an electrode on the surface of the hydrostatic guide, and when there are multiple hydrostatic pads facing the first guide-side electrode, the first pad-side electrode is provided as an electrode to be installed on at least one of the hydrostatic pads. Furthermore, the first guide-side electrode and the first pad-side electrode function as a first wireless power supply unit that performs a pair of electric field-coupled wireless power supply. When there is a second guide-side electrode that does not short-circuit with the first wireless power supply unit, and multiple static pressure pads facing the second guide-side electrode, the second pad-side electrode is provided as an electrode to be installed on at least one static pressure pad. The second guide-side electrode and the second pad-side electrode function as a second wireless power supply unit that performs a pair of electric field coupling type wireless power supply. Between the first and second wireless power supply units, AC current is supplied wirelessly from the stage fixed unit to the stage movable unit in a non-contact manner. A power supply device according to any one of claims 1 to 4.

8. A pressure detection means for detecting the pressure of the fluid supplied to the hydrostatic fluid bearing, The stage movable part is provided with a power storage means, If the pressure detected by the pressure detection means falls below a preset value, the control circuit of the stage device outputs an error signal to the movable part of the stage device, causing the stage device to perform an emergency stop operation and to stop the wireless power supply. A power supply device according to any one of claims 1 to 4.

Images