Control system and method for controlling the position of a control object

Abstract

To provide a control system capable of more precisely controlling the position of an object to be controlled.SOLUTION: A control system 1 for controlling a position of a control target includes a surface acoustic wave element, a power supply, an input signal generation unit, a displacement measurement unit, and a position control unit, the surface acoustic wave element includes a propagation surface and at least one electrode that induces a surface acoustic wave on the propagation surface, the surface acoustic wave is configured to induce a displacement along a displacement direction intersecting the propagation surface on the propagation surface, and the power supply is configured to input an electric signal for propagating a standing wave of the surface acoustic wave to the propagation surface to the electrode. The input signal generation unit is configured to input an input signal to a specific position on the propagation surface to cause a response from the specific position to be output, the displacement measurement unit is configured to generate a measurement signal indicating a temporal change in displacement in a displacement direction at the specific position on the propagation surface induced by a standing wave of the surface acoustic wave, and the position control unit controls the position of the control target based on a modulation mode of the measurement signal caused by the standing wave.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a control system and method for controlling the position of a controlled object. [Background technology]

[0002] Patent Document 1 discloses a technology related to a small displacement sensor that is not affected by the characteristics of the propagation path of a surface acoustic wave. The displacement sensor includes a surface acoustic wave propagation material and two surface acoustic wave elements having comb-teeth electrodes, with the surface acoustic wave propagation surfaces facing each other across the propagation material and configured so that the distance between them in the propagation direction of the surface acoustic waves is variable. A high-frequency signal applied to the comb-teeth electrode of one of the surface acoustic wave elements excites a surface acoustic wave, which propagates from the surface acoustic wave propagation surfaces through the propagation material, thereby obtaining, in the comb-teeth electrode of the other surface acoustic wave element, a high-frequency signal that is delayed from the high-frequency signal applied to the comb-teeth electrode of the one surface acoustic wave element. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-216440 Summary of the Invention [Problem to be solved by the invention]

[0004] However, there is room for further improvement in the technology for precise position control using standing waves of surface acoustic waves. [Means for solving the problem]

[0005] According to one aspect of the present invention, there is provided a control system for controlling the position of a controlled object, the control system comprising at least one surface acoustic wave element, a power supply, an input signal generation unit, a displacement measurement unit, and a position control unit, wherein the surface acoustic wave element comprises a propagation surface and at least one electrode that induces a surface acoustic wave on the propagation surface, the surface acoustic wave being configured to induce a displacement on the propagation surface along a displacement direction that intersects the propagation surface, the power supply is configured to input an electrical signal that propagates a standing wave of the surface acoustic wave on the propagation surface to the electrode, the input signal generation unit is configured to input an input signal to a specific position on the propagation surface and output a response from the specific position, the displacement measurement unit is configured to generate a measurement signal that indicates a change over time in the displacement direction at the specific position on the propagation surface induced by the standing wave of the surface acoustic wave, and the position control unit is configured to control the position of the controlled object based on a modulation pattern of the measurement signal by the standing wave.

[0006] With this configuration, the position of the controlled object can be controlled more precisely. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a control system. [Figure 2] FIG. 2 is a block diagram showing the hardware configuration of a user terminal. [Figure 3] FIG. 2 is a diagram illustrating an example of the configuration of a control device. [Figure 4] 10 is a flowchart illustrating an example of the flow of a control method executed by the control system. [Figure 5] FIG. 10 is a diagram illustrating an example of the configuration of a control device using a standing wave having a two-dimensional distribution of antinodes and nodes. [Figure 6] FIG. 1 is a diagram showing an example of a processing system 2 equipped with a plurality of control devices defined by a plurality of different displacement directions. [Figure 7] FIG. 10 is a diagram illustrating a modified example of the control system. DETAILED DESCRIPTION OF THE INVENTION

[0008] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings. Various features shown in the following embodiments can be combined with each other.

[0009] Incidentally, the program for realizing the software appearing in one embodiment may be provided as a non-transitory computer-readable medium, or may be provided so that it can be downloaded from an external server, or may be provided so that the program is started on an external computer and its functions are realized on a client terminal (so-called cloud computing).

[0010] Furthermore, various information processing according to an embodiment may realize input and output corresponding to the input. Here, the form of information referenced in such information processing (hereinafter referred to as reference information) is not limited as long as an output is obtained as a result of the input. The reference information may be, for example, rule-based information such as a database, a lookup table, or a predetermined function (including a decision formula such as a regression formula constructed using a statistical method), a trained model that has previously trained the correlation between input and output, or a large-scale language model that can output a desired result by inputting a prompt.

[0011] In one embodiment, a "unit" may include, for example, a combination of hardware resources implemented by a circuit in the broad sense and software information processing that can be specifically realized by these hardware resources. In one embodiment, various information is handled, and this information is represented, for example, by physical values ​​of signal values ​​representing voltage and current, high and low signal values ​​as a binary bit set consisting of 0 or 1, or quantum superposition (so-called quantum bits), and communication and calculations can be performed on a circuit in the broad sense.

[0012] Furthermore, a circuit in the broad sense is a circuit realized by at least an appropriate combination of a circuit, circuitry, processor, memory, etc. The processor may be a general-purpose processor or a dedicated circuit. That is, it includes an application specific integrated circuit (ASIC), a programmable logic device (e.g., a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), and a field programmable gate array (FPGA)), etc.

[0013] 1. Control system configuration example First, an example of the configuration of a control system according to this embodiment will be described. FIG. 1 is a diagram showing an example of the configuration of a control system. For example, the control system 1 includes a processing system 2 and a user terminal 10. The processing system 2 and the user terminal 10 are configured to communicate with each other via a telecommunications line. In one embodiment, the control system 1 is made up of one or more devices or components. For example, if the control system 1 is made up of only a control device 4, the control system 1 can be the control device 4. These components will be described below.

[0014] <Processing System 2> The processing system 2 includes a workpiece 3, a drive stage 21, a processing device 22, and a control device 4.

[0015] The workpiece 3 is an object to be processed in the present control system 1, and is particularly a member to be microfabricated (for example, a semiconductor precursor that will become a semiconductor through microfabrication).

[0016] The drive stage 21 is configured to integrally move the processing device 22. For example, the drive stage 21 is configured to be able to move the processing device 22 in three directions using a plurality of independent stepping motors or the like.

[0017] The processing device 22 is configured to process the workpiece 3. For example, when the workpiece 3 is a semiconductor precursor (e.g., a silicon wafer) to be processed by the processing device 22, the processing device 22 is configured to process the semiconductor precursor by outputting a particle beam or light to the semiconductor precursor. This configuration can improve the processing accuracy when manufacturing semiconductors. In this embodiment, the processing device 22 is configured to output a processing beam L0 as a laser to the workpiece 3.

[0018] The control device 4 is used to control the position of a control object. For example, the control device 4 is configured to control the relative position of the processing device 22 as a control object with respect to the workpiece 3. With such a configuration, it is possible to more precisely identify the processing position of the workpiece 3 using the processing device 22 (for example, the output position of the processing beam L0). Details of the control device 4 will be described later.

[0019] <User terminal 10> 2 is a block diagram showing the hardware configuration of a user terminal. The user terminal 10 includes a communication bus 100, a communication unit 101, a storage unit 102, a processor 103, a display unit 104, and an input unit 105, and these components are electrically connected via the communication bus 100 inside the user terminal 10. Each component will be further described below.

[0020] The communication unit 101 is preferably a wired communication means such as USB, IEEE1394, Thunderbolt (registered trademark), or wired LAN network communication, but may also include wireless LAN network communication, mobile communication such as 3G / LTE / 5G, or BLUETOOTH (registered trademark) communication as needed. That is, it is more preferable to implement it as a collection of multiple communication means. That is, the user terminal 10 may communicate various information from the outside via the communication unit 101 and the network.

[0021] The memory unit 102 stores various pieces of information defined above. This can be implemented, for example, as a storage device such as a solid state drive (SSD) that stores various programs related to the user terminal 10 executed by the processor 103, or as a memory such as a random access memory (RAM) that stores temporarily required information (arguments, arrays, etc.) related to the program operations. The memory unit 102 stores various programs, variables, etc. related to the user terminal 10 executed by the processor 103.

[0022] The processor 103 processes and controls the overall operations related to the user terminal 10. The processor 103 is, for example, a central processing unit (CPU) not shown. The processor 103 realizes various functions related to the user terminal 10 by reading out predetermined programs stored in the storage unit 102. In other words, information processing by software stored in the storage unit 102 is specifically realized by the processor 103, which is an example of hardware, and can be executed as each functional unit included in the processor 103. These will be described in more detail in the next section. Note that the processor 103 is not limited to being single, and multiple processors 103 may be provided for each function. A combination of these may also be used.

[0023] The processor 103 is configured to function as an acquisition unit and acquire information from the machining system 2 or other devices. The processor 103 is configured to acquire various pieces of information by reading various pieces of information stored in a storage area that is at least a part of the memory unit 102 and writing the read information to a working area that is at least a part of the memory unit 102. The storage area is, for example, an area of ​​the memory unit 102 that is implemented as a storage device such as an SSD. The working area is, for example, an area that is implemented as a memory such as a RAM. Note that acquisition by the processor 103 includes acquiring output results from each functional unit included in the processor 103.

[0024] The processor 103 is configured as a display processing unit to display various information. The information can be presented to a user via a display unit 104 of the user terminal 10 (described later) or another device. In such a case, for example, the processor 103 controls the display unit 104 of the user terminal 10 to display visual information such as a screen, an image including a still image or a video, an icon, or a message. The processor 103 may generate only rendering information for displaying the visual information on the user terminal 10. Note that the processor 103 may present the output information to a user without going through the user terminal 10 or another device user.

[0025] The display unit 104 may be included in the housing of the user terminal 10 or may be externally attached. The display unit 104 displays a graphical user interface (GUI) screen that can be operated by the user. This is preferably implemented by selectively using display devices such as a CRT display, a liquid crystal display, an organic EL display, and a plasma display depending on the type of user terminal 10.

[0026] The input unit 105 is configured to be able to accept input from a user. The input unit 105 may be included in the housing of the user terminal 10 or may be externally attached. For example, the input unit 105 may be implemented as a touch panel integrated with the display unit 104. The touch panel allows the user to input tapping, swiping, and the like. Of course, instead of a touch panel, a switch button, a mouse, a QWERTY keyboard, a voice recognition device, a gesture detection device, a gaze detection device, a biosignal detection device, an imaging device, and the like may be used. That is, the input unit 105 accepts an operation input made by the user. In response, the input unit 105 transfers a signal corresponding to the operation input to the processor 103 via the communication bus 100. The processor 103 may execute predetermined control and calculations as necessary.

[0027] The user terminal 10 can be configured to monitor and control the status of each component included in the processing system 2, such as the drive stage 21 and the processing device 22.

[0028] 2. Example of the configuration of the control device 4 Next, a configuration example of the control device 4 will be described. Fig. 3 is a diagram showing a configuration example of the control device. As shown in Fig. 3, the control device 4 includes a laser light source 41, an optical system 42, at least one surface acoustic wave element 44, a power source 43, at least one displacement measurement unit 45, and a position control unit 46. In this embodiment, the control device 4 includes one surface acoustic wave element 44.

[0029] The laser light source 41 is configured to output an incident laser beam L1. The specific embodiment of the incident laser beam L1 is arbitrary.

[0030] The optical system 42 is configured to distribute the incident laser beam L1 from the laser light source 41 to multiple laser beams. The optical system 42 for distributing light can be implemented as appropriate by distributing the incident laser beam L1 using optical elements such as half mirrors. The optical system 42 is configured to maintain the phase information of the incident laser beam L1. This allows accurate information such as distance to be obtained by a phase comparison technique such as heterodyne detection using the incident laser beam L1. In this embodiment, the optical system 42 is configured to distribute the incident laser beam L1 to a first incident laser beam L11, a second incident laser beam L12, and a third incident laser beam L13. The phases of the first incident laser beam L11, the second incident laser beam L12, and the third incident laser beam L13 correspond to the optical path lengths from the laser light source 41.

[0031] The power supply 43 is configured to output an electric signal (for example, an AC voltage signal). The waveform of the electric signal may be any waveform, such as a sine wave, a rectangular wave, or a triangular wave, as long as it contains a specific frequency as a main component and is configured to induce a standing wave ST of a surface acoustic wave (SAW), which will be described later. Furthermore, the electric signal does not have to be a continuous wave, and may be an intermittent wave such as a periodic pulse wave.

[0032] The surface acoustic wave element 44 is configured to generate a piezoelectric effect when an electric signal is input from the power source 43. The piezoelectric effect induces a displacement due to an electric field generated in the surface acoustic wave element 44 based on the electric signal. For convenience of explanation, the direction in which the displacement is induced will be referred to as a displacement direction D1. The surface acoustic wave element 44 may be formed, for example, using a ferroelectric material that generates a piezoelectric effect in the displacement direction D1 (e.g., a ferroelectric material aligned with the displacement direction D1). The specific shape of the surface acoustic wave element 44 is arbitrary, but it may be formed as a thin film. As an example, the surface acoustic wave element 44 includes a propagation surface 441 and at least one electrode 442 (a pair of electrodes 442A and 442B in this embodiment).

[0033] The propagation surface 441 is defined, for example, to have a normal along the displacement direction D1 (at least when no displacement is induced). The propagation surface 441 is formed, for example, in a planar shape. For convenience of explanation, the two directions defining the plane of the propagation surface 441 will be referred to as a first in-plane direction D2 and a second in-plane direction D3 below. The first in-plane direction D2 and the second in-plane direction D3 are both perpendicular to the displacement direction D1, and the first in-plane direction D2 and the second in-plane direction D3 are perpendicular to each other. In this embodiment, the displacement direction D1, the first in-plane direction D2, and the second in-plane direction D3 define a three-dimensional spatial coordinate system that is orthogonal to each other.

[0034] A pair of electrodes 442A, 442B are provided on the propagation surface 441 and connected to a power source 43. The electrodes 442A, 442B are arranged on the propagation surface 441 facing each other in a first in-plane direction D2. An electric signal from the power source 43 is input to the propagation surface 441 via the electrodes 442A, 442B. This allows a displacement in the displacement direction D1 based on the piezoelectric effect to be induced in the surface acoustic wave element 44. At this time, the displacement propagates as a surface acoustic wave on the propagation surface 441. The displacement induced based on the electric signal transmitted to the electrodes 442A, 442B propagates on the propagation surface 441 as a surface acoustic wave traveling in the first in-plane direction D2 between the electrodes 442A, 442B. The electrodes 442A, 442B are, for example, comb-shaped electrodes, but any other electrodes may be used as long as they can induce surface acoustic waves.

[0035] Displacement due to the piezoelectric effect propagates on the propagation surface 441 as a surface acoustic wave (SAW). The surface acoustic wave is configured to induce a displacement on the propagation surface 441 along a displacement direction D1 that intersects with the propagation surface 441. In this embodiment, the surface acoustic wave propagates in a first in-plane direction D2 between a pair of electrodes 442A and 442B. The surface acoustic wave propagates so as to have an in-phase plane along the first in-plane direction D2. The surface acoustic waves propagating in the first in-plane direction D2 from the electrodes 442A and 442B overlap with each other to form a standing wave ST on the propagation surface 441. For example, the electrodes 442A and 442B input an electrical signal to the propagation surface 441 to induce a surface acoustic wave on the propagation surface 441, thereby propagating a standing wave ST of the surface acoustic wave on the propagation surface 441. As a result, antinode regions where the change over time (amplitude) of the displacement in displacement direction D1 is greatest and node regions where the change over time of the displacement in displacement direction D1 is almost zero appear on propagation surface 441. In other words, the length of propagation surface 441 in the first in-plane direction D2, the positions and shapes of electrodes 442A and 442B, and the waveform of the electrical signal input from power source 43 are configured to induce such standing wave ST.

[0036] The incident laser beams L1 (at least the first incident laser beam L11, and in this embodiment, the second incident laser beam L12) distributed by the optical system 42 are output to the propagation surface 441. For ease of explanation, the position on the propagation surface 441 from which the first incident laser beam L11 is output will be referred to as a specific position P1, and the position on the propagation surface 441 from which the second incident laser beam L12 is output will be referred to as a reference position P2. The first incident laser beam L11 is reflected at the specific position P1 and input to the optical system 42 as a specific laser beam L2. The second incident laser beam L12 is reflected at the reference position P2 and input to the optical system 42 as a reference laser beam L3. The specific laser beam L2 and the reference laser beam L3 are output to a displacement measurement unit 45 (described later) via the optical system 42, together with the third incident laser beam L13. In this way, the laser light source 41 and the optical system 42 are an example of an input signal generating unit configured to input an incident laser (first incident laser L11) as an input signal to a specific position P1 on the propagation surface 441, and output reflected light (specific laser L2) as a response from the specific position P1, and the first incident laser L11 corresponds to the input signal in this embodiment.

[0037] The specific position P1 may be any position having a non-zero finite amplitude. Preferably, the specific position P1 is included in the antinode region of the standing wave ST. This configuration makes it easier to detect the time change in displacement at the specific position P1 due to the standing wave ST. The reference position P2 is a position on the propagation surface 441 that has a specified positional relationship with the specific position P1, for example, a position where the amplitude of the standing wave ST is smaller than that of the specific position P1. Preferably, the reference position P2 is included in the node region of the standing wave ST. This configuration makes it easier to detect the time change in displacement at the specific position P1 due to the standing wave ST based on the reference position P2, thereby further improving the accuracy of position control by the control device 4. The time change in displacement in the displacement direction D1 at the specific position P1 appears as a time change in a response (here, the specific laser L2) to a signal (here, the first incident laser L11) output to the specific position P1.

[0038] The displacement measuring unit 45 is configured to generate a specific measurement signal as a measurement signal indicating a change over time in displacement in a displacement direction D1 at a specific position P1 on the propagation surface 441, induced by a standing wave ST of a surface acoustic wave. For example, the displacement measuring unit 45 is configured to generate a measurement signal representing a detection result of a change over time in a response (here, the specific laser L2) to a signal (here, the first incident laser L11) output to the specific position P1. The measurement signal includes information regarding the change over time in the response. For example, the displacement measuring unit 45 is a photodetector that detects lasers (here, the third incident laser L13, the specific laser L2, and the reference laser L3) output from the optical system 42. The photodetector may be any device capable of detecting lasers, such as a photodiode, a CMOS (Complementary Metal-Oxide-Semiconductor) sensor, or a CCD (Charge Coupled Device) sensor. These photodetectors are configured to output a photocurrent (or a voltage that attempts to flow the photocurrent) as a measurement signal. The displacement measuring unit 45 may have any specific configuration as long as it can measure the change over time in response to an input at the specific position P1 caused by a standing wave ST induced by the electrodes 442 a and 442 b. As an example, the displacement measuring unit 45 includes, as photodetectors, a specific detector 451, a standard detector 452, and a reference detector 453.

[0039] The specific detector 451 is configured to generate a specific measurement signal by detecting reflected light (here, specific laser L2) of the incident laser L1 outputted to the specific position P1. The phase of the specific laser L2 detected by the specific detector 451 depends on the optical path length from the laser light source 41 to the specific detector 451 via the specific position P1. The optical path length changes over time depending on the displacement of the specific position P1 in the displacement direction D1 associated with the standing wave ST, particularly in the optical path portion between the optical system 42 and the specific position P1. Therefore, the change over time in the phase of the specific laser L2 detected by the specific detector 451 represents the change over time in the displacement at the specific position P1.

[0040] The reference detector 452 is configured to output a reference measurement signal by detecting a third incident laser beam L13 as a reference beam distributed from the incident laser L1. Because the third incident laser beam L13 is output toward the reference detector 452 without passing through the surface acoustic wave element 44, the optical path length from the laser light source 41 to the reference detector 452 does not depend on the displacement in the displacement direction D1 caused by the standing wave ST. As an example, the optical path length from the laser light source 41 to the reference detector 452 is constant regardless of the displacement in the displacement direction D1 caused by the standing wave ST. Therefore, heterodyne detection using the specific measurement signal and the reference measurement signal can obtain the correspondence relationship between the amplitude at the specific position P1 and the change in phase of the specific laser beam L2. In other words, the displacement measurement unit 45 is configured to generate a specific measurement signal indicating the time change in the displacement in the displacement direction D1 at the specific position P1 on the propagation surface 441 based on the phase difference between the reference beam distributed from the incident laser L1 and the reflected beam. According to this configuration, the distance in the displacement direction D1 can be more accurately determined based on the detection result of the specific laser beam L2 as reflected light.

[0041] The method for obtaining the correspondence between the change in amplitude and phase at such a specific position P1 is not limited to heterodyne detection based on the specific laser L2 and another laser (e.g., a third incident laser L13, etc.), but can be any method based on the interference pattern of the specific laser L2, for example, a method using an interferometer such as a Michelson interferometer.

[0042] It is preferable that the main frequency component characterizing the signal measured by the displacement measuring unit 45 such as the specific detector 451 (for example, the frequency of interference fringes or the frequency used in heterodyne detection) is greater than the frequency of the standing wave ST. With this configuration, the measurement accuracy of the displacement of the standing wave ST can be improved.

[0043] Furthermore, the specific laser L2 (and further the incident laser L1) is not limited to a laser including a single frequency component, but may be a laser including multiple frequency components f1 and f2 (for example, a Zeeman laser). In this case, the displacement measurement unit 45 may perform heterodyne detection based on the difference (f1-f2) between the frequency components.

[0044] The reference detector 453 is configured to detect the reference laser L3 to generate a reference measurement signal that indicates a change in displacement over time in the displacement direction D1 at the reference position P2. Similar to the specific detection signal, the reference measurement signal contains information about the optical path length from the laser light source 41 to the reference detector 453 as a change in the phase of the reference laser L3 over time. As with the standard measurement signal, heterodyne detection of the specific measurement signal using the reference measurement signal can be performed to obtain a correspondence relationship between the amplitude at the specific position P1 and a change in the phase of the specific laser L2. Therefore, the reference laser L3 can be used as a reference light, similar to the third incident laser L13.

[0045] The position control unit 46 controls the position of the controlled object based on the modulation pattern of the measurement signal (particularly the specific measurement signal) measured by the displacement measurement unit 45 by the standing wave ST. For example, the position control unit 46 acquires (e.g., from the power supply 43 itself) a specific frequency f that characterizes the periodicity of the electrical signal from the power supply 43. Then, the position control unit 46 extracts components synchronized with the specific frequency f from the time changes in the phase and amplitude of the specific measurement signal, the reference measurement signal, and the reference detection signal using lock-in detection. Based on the extracted components, the position control unit 46 determines the relationship between the modulation pattern of the amplitude of the standing wave ST at the specific position P1 and the distance in the displacement direction D1, and associates the detection result of a detection system (e.g., an optical system using a laser light source similar to the laser light source 41) for identifying the position of the actuation stage 21 with the position (or the amount of change in position) of the actuation stage 21 according to the correlation. The position control unit 46 controls the position of the actuation stage 21 according to an external command based on the result of the association. In this embodiment, one control device 4 can identify information about the position of the drive stage 21 in one axial direction (for example, displacement direction D1) and control the position of the drive stage 21 in that one axial direction. The position control results by the position control unit 46 are transmitted to the user terminal 10, and the user can grasp the position control results by the position control unit 46 via the user terminal 10. The user can also transmit a movement sequence of the position control unit 46 via the user terminal 10. The drive stage 21 is driven in accordance with that movement sequence.

[0046] According to the above configuration, minute displacements in the displacement direction D1 of the standing wave ST can be associated with the position of the control object, so that the position of the control object can be controlled with high precision.

[0047] 3. An example of the flow of the control method executed by the control system Next, an example of the flow of a control method executed by the control system 1 will be described. FIG. 4 is a flowchart showing an example of the flow of a control method executed by the control system. The flowchart may include any exception processing not shown. Exception processing includes interruption of the control or omission of each process. Selection or input performed in the control method may be based on a user operation, or may be performed automatically without relying on a user operation.

[0048] [Step S1] First, in step S1, the power supply 43 induces a standing wave ST on the propagation surface 441 of the surface acoustic wave element 44. Specifically, the power supply 43 applies an AC voltage signal to the electrodes 442A and 442B to induce a standing wave ST of a surface acoustic wave on the propagation surface 441 of the surface acoustic wave element 44 so as to induce a displacement along a displacement direction D1 intersecting the propagation surface 441.

[0049] [Step S2] Next, in step S2, the laser light source 41 introduces the incident laser L1 into the optical system .

[0050] [Step S3] Next, in step S3, the optical system 42 divides the introduced incident laser L1 into lasers (e.g., first incident laser L11 and second incident laser L12) that are output toward the surface acoustic wave element 44, and lasers (e.g., third incident laser L13) that are output toward the displacement measuring unit 45 without passing through the surface acoustic wave element 44.

[0051] [Step S4] Next, in step S4, the optical system 42 outputs the incident laser L1 distributed from the optical system 42 to the propagation plane 441. Specifically, the optical system 42 outputs a first incident laser L11 toward a specific position P1 on the propagation plane 441, and outputs a second incident laser L12 toward a reference position P2 on the propagation plane 441. As a result, the specific laser L2 reflected from the specific position P1 and the reference laser L3 reflected from the reference position P2 are introduced again into the optical system 42.

[0052] [Step S5] Next, in step S5, the optical system 42 outputs each of the distributed incident lasers L1 toward the displacement measuring unit 45. Specifically, the optical system 42 outputs a specific laser L2 to the specific detector 451, outputs a third incident laser L13 to the reference detector 452, and outputs a reference laser L3 to the reference detector 453.

[0053] [Step S6] Next, in step S6, the displacement measuring unit 45 detects the lasers (specific laser L2, reference laser L3, and third incident laser L13) output via the optical system 42. Through this detection, the displacement measuring unit 45 measures the change over time in displacement in a displacement direction D1 at a specific position P1 on the propagation surface 441, which is induced by the standing wave ST of the surface acoustic wave, and generates a measurement signal indicating the change over time in the displacement.

[0054] [Step S7] Next, the position control unit 46 controls the position of the processing device 22 as a control target based on the generated measurement signal. For example, the position control unit 46 performs heterodyne detection on the specific measurement signal measured by the specific detector 451 using the reference measurement signal measured by the reference detector 452 or the reference measurement signal measured by the reference detector 453, extracts components synchronized with the specific frequency f of the electrical signal of the power supply 43 by lock-in detection from the result of the heterodyne detection, and uses the extracted components to construct information indicating the relationship between the displacement in the displacement direction D1 synchronized with the specific frequency f and the phase (particularly the phase difference). The position control unit 46 controls the position of the processing device 22 based on this information.

[0055] A method for controlling the position of the processing device 22 as a control target can be performed through the above steps. With this configuration, minute displacements in the displacement direction D1 of the standing wave ST can be associated with the position of the control target, so that the position of the control target can be controlled with high precision. Note that the method does not need to include all of the above steps, and may include only some of the steps.

[0056] 4. An example of a control device using a standing wave ST with two-dimensional antinodes and nodes In the previous section, a control system 1 using a standing wave ST having a one-dimensional distribution of antinodes and nodes along the first in-plane direction D2 was described. However, the specific embodiment of the control system 1 is not limited to this. In this section, an example of a control device 4 using a standing wave ST having a two-dimensional distribution of antinodes and nodes is described. FIG. 5 is a diagram showing an example configuration of a control device using a standing wave having a two-dimensional distribution of antinodes and nodes. Note that, among the components included in the control system 1 described in this section, components common to the components included in the control system 1 described in the previous section are designated by the same numbers and description thereof may be omitted. Here, the control device 4 includes a laser light source 41, an optical system 42, a power supply 43, a surface acoustic wave element 44, a displacement measurement unit 45, and a position control unit 46, similar to the control device 4 described in the previous section. This section will focus on the configuration of the surface acoustic wave element 44, which is the main difference from the control device 4 described in the previous section. The position at which the laser is output from the laser light source 41 and the optical system 42 toward the surface acoustic wave element 44 can be set appropriately.

[0057] As shown in FIG. 5, the surface acoustic wave element 44 includes a rotating unit 5. The rotating unit 5 rotates the propagation surface 441 in a plane intersecting the displacement direction D1. In this embodiment, the rotating unit 5 is configured to rotate the entire surface acoustic wave element 44 around a rotation axis C extending in the displacement direction D1. The rotating unit 5 is configured to be electrically driven by, for example, a stepping motor or the like. The rotation axis C is defined to pass through the propagation surface 441.

[0058] Moreover, the surface acoustic wave element 44 according to this embodiment includes a plurality of pairs of electrodes 442 (specifically, a pair of first electrodes 442a1, a2 and a pair of second electrodes 442b1, b2). The first electrodes 442a1, 442a2 are arranged spaced apart from each other in a first in-plane direction D2 on the propagation surface 441. The second electrodes 442b1, 442b2 are arranged spaced apart from each other in a second in-plane direction D3 on the propagation surface 441. The first electrodes 442a1, 442a2 transmit an electrical signal from the power source 43 onto the propagation surface 441, thereby generating surface acoustic waves that travel along the first in-plane direction D2. The second electrodes 442b1, 442b2 transmit an electrical signal from the power source 43 onto the propagation surface 441, thereby generating surface acoustic waves that travel along the second in-plane direction D3. Hereinafter, for convenience of explanation, the surface acoustic waves generated by the first electrodes 442a1 and 442a2 will be referred to as the "first surface acoustic wave," and the surface acoustic waves generated by the second electrodes 442b1 and 442b2 will be referred to as the "second surface acoustic wave." The first surface acoustic waves generated by both of the pair of first electrodes 442a1 and 442a2 overlap, and the second surface acoustic waves generated by both of the pair of second electrodes 442b1 and 442b2 overlap. As a result, the first surface acoustic wave and the second surface acoustic wave each form an independent standing wave. The standing wave based on the first surface acoustic wave is formed to have alternating antinodes and nodes along the first in-plane direction D2 and an in-phase surface along the second in-plane direction D3. The standing wave based on the second surface acoustic wave is formed to have alternating antinodes and nodes along the second in-plane direction D3 and an in-phase surface along the first in-plane direction D2. By superimposing these two standing waves, a standing wave ST is induced on the propagation surface 441, in which antinodes AN are arranged in a two-dimensional lattice pattern in which the first in-plane direction D2 and the second in-plane direction D3 are rotated 45 degrees within the propagation surface 441. The antinodes AN are regions in which the local amplitude of the standing wave ST is maximum. In contrast to the antinodes AN, the nodes are regions in which the local amplitude of the standing wave ST is minimum (ideally zero). In this embodiment, the first surface acoustic wave and the second surface acoustic wave propagate orthogonal to each other with the same period, and therefore a standing wave ST having antinodes AN located in a square lattice pattern is induced.However, the antinodes AN of the standing wave ST may be located in any two-dimensional lattice pattern expressed as a composite wave of multiple standing waves ST, such as a rectangular lattice pattern or a triangular lattice pattern. In other words, the electrodes 442a1, 442a2, 442b1, and 442b2 are arranged to induce a standing wave ST having antinodes AN located in a two-dimensional lattice pattern. As an example, the standing wave ST is formed so that the antinodes AN are located at positions on the propagation plane 441 through which the rotation axis C passes.

[0059] In this embodiment, the specific position P1 at which the specific laser beam L2 is output from the optical system 42 may be any one of the antinode AN regions. For example, the specific position P1 includes the position of the rotation center of the propagation plane 441 (here, the antinode region located on the rotation axis C). With this configuration, more diverse position information (e.g., information regarding the orientation of the processing device 22 as the control target) can be analyzed based on the influence of time changes in the measurement signal from the rotating unit 5. Furthermore, in this embodiment, the reference position P2 is a position on the propagation plane 441 that has a specified positional relationship with the specific position P1, for example, a position where the amplitude of the standing wave ST is smaller than that of the specific position P1. Preferably, the reference position P2 is located so as to correspond to the antinode region of the standing wave ST when the rotation angle of the rotating unit 5 is a predetermined value. That is, in this embodiment, unlike the specific position P1 where the amplitude of the standing wave ST is constant regardless of the rotation angle of the rotating unit 5, the reference position P2 is a position where the amplitude varies depending on the rotation angle of the rotating unit 5.

[0060] The displacement measurement unit 45 and the position control unit 46 can identify the orientation of the processing device 22 (e.g., the inclination from the direction corresponding to the displacement direction D1) by comparing the specific laser L2 with the reference laser L3 based on the rotation angle (and rotation speed) of the rotation unit 5. Specifically, the displacement measurement unit 45 controls the rotation angle of the processing device 22 around the direction corresponding to the displacement direction D1 based on the modulation pattern of the displacement in the displacement direction D1 caused by the rotation angle of the rotation unit 5, and the position control unit 46 controls the rotation angle of the processing device 22 around the direction corresponding to the displacement direction D1 based on the modulation pattern of the displacement in the displacement direction D1 caused by the rotation angle of the rotation unit 5. This configuration allows for more precise control of the attitude of the processing device 22 as well as the position of the processing device 22. Note that the specific position P1 and the reference position P2 may be reversed. In other words, the specific position P1 or the reference position P2 only needs to include the position that is the rotation center (rotation axis C) of the propagation plane 441.

[0061] <Other> The above embodiment can be implemented as appropriate in the following manner, for example.

[0062] In the above-described embodiments, the control system 1 includes one control device 4 (i.e., one position control unit 46) and is configured to control the position of the control device 4 in a certain direction corresponding to one displacement direction D1 (or control the orientation based on that direction) based on the operation of the position control unit 46. However, this is not limiting. For example, the control system 1 may include multiple control devices 4 (specifically, position control units 46) corresponding to different displacement directions D1, and each control device 4 may control the position and / or orientation of the processing device 22 based on a direction corresponding to a different displacement direction D1. FIG. 6 is a diagram illustrating an example of a processing system 2 including multiple control devices defined by multiple different displacement directions. As shown in FIG. 6, the processing system 2 includes multiple control devices 4, including an X-position control device 4a, a Y-position control device 4b, and a Z-position control device 4c. The control devices 4a to 4c have the same configuration except that the displacement directions D1 for the respective surface acoustic wave elements 44 intersect (specifically, are orthogonal to each other). Each of the control devices 4a to 4c includes a surface acoustic wave element 44. The displacement measuring unit 45 and position control unit 46 of each of the control devices 4a to 4c identify and control the position of the processing device 22 in the direction corresponding to each displacement direction D1 based on the response of each surface acoustic wave element 44. In other words, at least one surface acoustic wave element 44 is a plurality of surface acoustic wave elements 44. Each of the plurality of surface acoustic wave elements 44 is arranged so that the displacement directions D1 of the surface acoustic wave elements 44 intersect with each other. The displacement measuring unit 45 is configured to generate a measurement signal (specific measurement signal) that indicates the change over time in displacement in the displacement direction D1 of each of the plurality of surface acoustic wave elements 44. With this configuration, the position of the processing device 22 can be precisely controlled in more diverse directions.

[0063] As described above, the number of electrodes 442 for forming the standing wave ST may be one. For example, the surface acoustic wave element 44 may form a standing wave by reflecting a surface acoustic wave generated from one electrode 442 at an end of the propagation surface 441, so that the surface acoustic wave traveling from the electrode 442 to the end of the propagation surface 441 and the surface acoustic wave reflected from the end overlap each other.

[0064] Furthermore, the controlled object is not limited to the processing device 22, but may be, for example, the workpiece 3. FIG. 7 is a diagram showing a modified example of the control system. As shown in FIG. 7, for example, the drive stage 21 may be configured to drive the workpiece 3 instead of (or in addition to) the processing device 22. In short, the controlled object may be any object as long as it is possible to identify (and control) the relative positional relationship between the processing device 22 and the workpiece 3. Furthermore, the control system 1 is not limited to applications to processing systems 2 such as semiconductor manufacturing equipment, but may be applied to any system that may move an object, such as an observation device for a microdomain. Examples of such observation devices include optical microscopes, electron microscopes, and tunneling scanning microscopes.

[0065] The displacement measuring unit 45 and the position control unit 46 may not be functionally separate entities but may be integrated. Furthermore, the measurement signal generated by the displacement measuring unit 45 may be processed by digital signal processing using the user terminal 10. That is, at least a part of the displacement measuring unit 45 and the position control unit 46 may be implemented using the user terminal 10. In this case, the user terminal 10 can function as the displacement measuring unit 45 and the position control unit 46.

[0066] It may be provided in the following manner.

[0067] (1) A control system for controlling the position of a controlled object, comprising at least one surface acoustic wave element, a power source, an input signal generation unit, a displacement measurement unit, and a position control unit, wherein the surface acoustic wave element comprises a propagation surface and at least one electrode that induces a surface acoustic wave on the propagation surface, the surface acoustic wave being configured to induce a displacement on the propagation surface along a displacement direction that intersects the propagation surface, the power source being configured to input an electrical signal that propagates a standing wave of the surface acoustic wave on the propagation surface to the electrode, the input signal generation unit being configured to input an input signal to a specific position on the propagation surface, thereby outputting a response from the specific position, the displacement measurement unit being configured to generate a measurement signal that indicates a change over time in the displacement direction at the specific position on the propagation surface, induced by the standing wave of the surface acoustic wave, and the position control unit being configured to control the position of the controlled object based on a modulation pattern of the measurement signal by the standing wave.

[0068] According to this configuration, minute displacements in the displacement direction of the standing wave can be associated with the position of the control object, so that the position of the control object can be controlled with high precision.

[0069] (2) In the control system described in (1) above, the input signal is an incident laser, the response is reflected light from the incident laser, and the displacement measurement unit is configured to generate the measurement signal by detecting the reflected light from the incident laser output at the specific position.

[0070] With this configuration, it is possible to perform more precise position control.

[0071] (3) In the control system described in (2) above, the displacement measurement unit is configured to generate the measurement signal based on a phase difference between a reference light distributed from the incident laser and the reflected light.

[0072] According to this configuration, the distance in the displacement direction based on the detection result of the reflected light can be more accurately determined by comparing it with the reference light.

[0073] (4) In the control system described in any one of (1) to (3) above, the surface acoustic wave element includes a rotation unit that rotates the propagation surface within a plane that intersects with the displacement direction, the displacement measurement unit is configured to generate a reference measurement signal that indicates a change in displacement over time in the displacement direction at a reference position on the propagation surface that has a specified positional relationship with the specific position, and the position control unit controls the rotation angle of the controlled object around the displacement direction based on the measurement signal and the reference measurement signal, based on a modulation mode of the displacement in the displacement direction due to the rotation angle of the rotation unit.

[0074] With this configuration, it becomes easier to detect the change over time in displacement due to standing waves at a specific position, and the precision of controlling the position of the controlled object can be further improved.

[0075] (5) In the control system described in (4) above, the specific position or the reference position includes a position that is the center of rotation of the propagation surface.

[0076] (6) A control system according to (4) or (5) above, wherein the electrodes are arranged to induce a standing wave having antinodes located in a two-dimensional lattice pattern.

[0077] (7) In the control system described in any one of (1) to (6) above, the at least one surface acoustic wave element is a plurality of surface acoustic wave elements, each of the plurality of surface acoustic wave elements is arranged so that the displacement directions of the surface acoustic wave elements intersect with each other, and the displacement measuring unit is configured to generate the measurement signal indicating the change over time in the displacement direction of each of the plurality of surface acoustic wave elements.

[0078] With this configuration, the position of the controlled object can be controlled precisely in a wider variety of directions.

[0079] (8) A control system according to any one of (1) to (7) above, comprising a processing device that processes a workpiece, and the control system is configured to control the relative position of the processing device as the control object with respect to the workpiece.

[0080] With this configuration, it is possible to improve the processing accuracy when manufacturing semiconductors.

[0081] (9) In the control system described in (8) above, the workpiece is a semiconductor precursor to be processed by the processing device, and the processing device is configured to process the semiconductor precursor by outputting a particle beam or light to the semiconductor precursor.

[0082] According to this configuration, the processing position of the workpiece using the processing device (for example, the output position of the processing beam L0) can be specified more precisely.

[0083] (10) A method for controlling the position of a controlled object, comprising the following steps: in the inducing step, inducing a standing wave of a surface acoustic wave on a propagation surface of a surface acoustic wave element so as to induce a displacement along a displacement direction intersecting the propagation surface; in the measuring step, measuring a change over time in the displacement direction at a specific position on the propagation surface induced by the standing wave of the surface acoustic wave, thereby generating a measurement signal indicating the change over time in the displacement; and in the signal processing step, controlling the position of the controlled object in the displacement direction based on the measurement signal. Of course, this is not the case.

[0084] Finally, while various embodiments of the present disclosure have been described, they are presented as examples and are not intended to limit the scope of the invention. The novel embodiments may be embodied in various other forms, and various omissions, substitutions, and modifications may be made without departing from the spirit of the invention. Such embodiments and modifications are intended to be included within the scope and spirit of the invention, as well as within the scope of the inventions and their equivalents as defined in the claims. [Explanation of symbols]

[0085] 1: Control system 2: Processing system 21: Driving stage 22: Processing equipment 3: Work 4: Control device 4a :X position control device 4b: Y position control device 4c:Z position control device 41: Laser light source 42:Optical system 43:Power supply 44: Surface acoustic wave element 441: Propagation surface 442 :Electrode 442A: Electrode 442B: Electrode 442a: Electrode 442a1: First electrode 442a2: First electrode 442b: Electrode 442b1: Second electrode 442b2: Second electrode 45: Displacement measurement unit 451: Specific detector 452: Reference detector 453: Reference detector 46: Position control section 5: Rotating part 10: User terminal 100: Communication bus 101: Communications Department 102: Storage section 103: Processor 104:Display section 105: Input section AN: Belly C: Rotation axis D1: Displacement direction D2: 1st in-plane direction D3: Second in-plane direction L0: Processing beam L1: Incident laser L11: First incident laser L12: Second incident laser L13: Third incident laser L2: Specific laser L3: Reference laser P1:Specific position P2: Reference position ST:Standing wave

Claims

1. A control system for controlling the position of a control object, comprising: The apparatus includes at least one surface acoustic wave element, a power supply, an input signal generating unit, a displacement measuring unit, and a position control unit, the surface acoustic wave element comprises a propagation surface and at least one electrode for inducing a surface acoustic wave on the propagation surface, the surface acoustic wave being configured to induce a displacement on the propagation surface along a displacement direction intersecting the propagation surface; the power supply is configured to input to the electrode an electrical signal that causes a standing wave of the surface acoustic wave to propagate on the propagation surface; the input signal generation unit is configured to input an input signal to a specific position on the propagation surface, thereby outputting a response from the specific position; the displacement measuring unit is configured to generate a measurement signal indicating a change over time in a displacement in the displacement direction at a specific position on the propagation surface, the change being induced by a standing wave of the surface acoustic wave; The position control unit is configured to control the position of the control target based on a modulation state of the measurement signal due to the standing wave.

2. 2. The control system of claim 1, the input signal is an incident laser; the response is a reflected light from the incident laser; The control system is configured such that the displacement measurement unit generates the measurement signal by detecting the reflected light of the incident laser output to the specific position.

3. 3. The control system of claim 2, The control system is configured such that the displacement measurement unit generates the measurement signal based on a phase difference between a reference light distributed from the incident laser and the reflected light.

4. 2. The control system of claim 1, the surface acoustic wave element includes a rotating portion that rotates the propagation surface within a plane that intersects with the displacement direction, the displacement measuring unit is configured to generate a reference measurement signal that indicates a change over time in displacement in the displacement direction at a reference position that has a specified positional relationship with the specific position on the propagation plane, the position control unit controls the rotation angle of the controlled object around the displacement direction based on the measurement signal and the reference measurement signal, based on a modulation pattern of displacement in the displacement direction due to the rotation angle of the rotating unit.

5. 5. The control system of claim 4, The specific position or the reference position comprises a position about which the propagation plane rotates.

6. 5. The control system of claim 4, The electrodes are arranged to induce a standing wave having antinodes located in a two-dimensional grid.

7. 2. The control system of claim 1, the at least one surface acoustic wave element is a plurality of surface acoustic wave elements; the plurality of surface acoustic wave elements are arranged such that the displacement directions of the surface acoustic wave elements intersect with each other; the displacement measuring unit is configured to generate the measurement signal indicating a time change in displacement of each of the plurality of surface acoustic wave elements in a displacement direction. Control system.

8. 2. The control system of claim 1, A processing device is provided to process the workpiece, The control system is configured to control the relative position of the processing device as the control target with respect to the workpiece.

9. 9. The control system of claim 8, the workpiece is a semiconductor precursor to be processed by the processing device; The processing device is configured to process the semiconductor precursor by outputting a particle beam or light to the semiconductor precursor.

10. A method for controlling a position of a control object, comprising: It includes the following steps: In the inducing step, a standing wave of the surface acoustic wave is induced on a propagation surface of the surface acoustic wave element so as to induce a displacement along a displacement direction intersecting the propagation surface; In the measurement step, a change in displacement over time in the displacement direction at a specific position on the propagation surface, which is induced by a standing wave of the surface acoustic wave, is measured to generate a measurement signal indicating the change in displacement over time; In the signal processing step, the position of the controlled object in the displacement direction is controlled based on the measurement signal.

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