WO2024084694A1

WO2024084694A1 - Optical device, optical processing device, optical processing method, and correction member

Info

Publication number: WO2024084694A1
Application number: PCT/JP2022/039339
Authority: WO
Inventors: 武利根岸; 正範荒井
Original assignee: 株式会社ニコン
Priority date: 2022-10-21
Filing date: 2022-10-21
Publication date: 2024-04-25

Abstract

This optical device is used for an optical processing device and is provided with: a deformable mirror (117) that a plurality of processing beams (ELs) from a processing light source (10) enter and that modifies the wavefront of the beam cross section of each of the plurality of processing beams (ELs); and a galvanomirror (161) that changes the traveling direction of the plurality of processing beams (ELs) from the deformable mirror (117) to change the positions where the processing beams (ELs) passing through an objective optical system (170) hit a workpiece (W).

Description

Optical device, optical processing device, optical processing method, and correction member

The present invention relates to an optical device, an optical processing device, an optical processing method, and a correction member.

Optical devices that irradiate light beams are used, for example, in optical processing devices. In optical devices, it is necessary to correct aberration. For example, it is possible to correct wavefront aberration by using a deformable mirror (see, for example, Patent Document 1) to change the wavefront of the reflected light beam.

U.S. Pat. No. 6,467,915

The first aspect of the present invention is an optical device used in an optical processing device that processes a workpiece by irradiating a processing beam from a light source onto the workpiece through an objective optical system, the optical device comprising: a wavefront modification member into which the processing beam from the light source is incident and that modifies the wavefront of the processing beam in the beam cross section; and a deflection member that changes the traveling direction of the processing beam from the wavefront modification member and changes the irradiation position on the workpiece of the processing beam that is irradiated onto the workpiece through the objective optical system.

The second aspect of the present invention is an optical device used in an optical processing device that processes a workpiece by irradiating a processing beam from a light source onto the workpiece through an objective optical system, and includes a wavefront modification member into which the processing beam from the light source is incident and which modifies the wavefront of the processing beam in the beam cross section, a relay optical system into which the processing beam emitted from the wavefront modification member is incident, and a deflection member that changes the traveling direction of the processing beam from the relay optical system to cause it to be incident on the objective optical system and change the irradiation position of the processing beam on the workpiece, and the relay optical system is an optical device that optically conjugates the wavefront modification surface of the wavefront modification member with the deflection member.

The third aspect of the present invention is an optical device used in an optical processing device that processes a workpiece by irradiating a processing beam from a light source onto the workpiece through an objective optical system, the optical device comprising: a beam splitting member that splits the processing beam from the light source into multiple processing beams; a conjugate optical system on which the multiple processing beams emitted from the beam splitting member are incident and form a conjugate position optically conjugate with the beam splitting surface of the beam splitting member; and a wavefront changing member on which the multiple processing beams from the conjugate optical system are incident and that changes the wavefronts in the beam cross section of the multiple processing beams that are emitted and incident on the objective optical system, the wavefront changing surface of the wavefront changing member being located at the conjugate position of the beam splitting surface.

The fourth aspect of the present invention is an optical device used in an optical processing device that processes a workpiece by irradiating a processing beam from a light source onto the workpiece through an objective optical system, the optical device comprising: a polarizing beam splitter onto which the processing beam from the light source is incident; a wavefront changing member into which the processing beam via the polarizing beam splitter is incident and which changes the wavefront of the exiting processing beam in the beam cross section and causes the processing beam to be incident on the polarizing beam splitter; and a quarter-wave plate arranged in the optical path of the processing beam with the wavefront changed.

The fifth aspect of the present invention is an optical device used in an optical processing device that processes a workpiece by irradiating a processing beam from a light source onto the workpiece through an objective optical system, and includes a wavefront modification member into which the processing beam from the light source is incident and which modifies the wavefront of the processing beam in a beam cross section, and the wavefront modification member modifies the wavefront of the processing beam emitted from the wavefront modification member to correct a non-rotationally symmetric component of the wavefront of the processing beam from the objective optical system when changing the focusing position of the processing beam from the objective optical system in relation to the optical axis direction of the objective optical system.

The sixth aspect of the present invention is an optical processing device that processes a workpiece by irradiating a processing beam from a light source through an objective optical system onto the workpiece, and is an optical processing device that includes the optical device described above.

The seventh aspect of the present invention is an optical processing method for processing a workpiece by irradiating a processing beam from a light source onto the workpiece through an objective optical system, in which the processing beam from the light source is incident on the optical device described above, and the processing beam from the optical device is irradiated onto the workpiece via the objective optical system.

The eighth aspect of the present invention is a correction member used in an optical device that irradiates a light beam from a light source via a deflection member and an objective optical system onto a workpiece in a scannable manner, the correction member including a wavefront modification member disposed in an optical path between the light source and the deflection member, which modifies the wavefront in the beam cross section of the light beam heading toward the deflection member, the wavefront modification member being a correction member that corrects the change in the wavefront in the beam cross section of the light beam from the objective optical system that occurs with the operation of the deflection member.

The ninth aspect of the present invention is a correction member used in an optical device that irradiates a light beam from a light source via a deflection member and an objective optical system onto a workpiece in a scannable manner, and includes a wavefront modification member that is disposed in an optical path between the light source and the deflection member and modifies the wavefront in the beam cross section of the light beam heading toward the deflection member, and the wavefront modification member is a correction member that corrects the change in the wavefront in the beam cross section of the light beam from the objective optical system that occurs with the movement of the irradiation position of the light beam irradiated from the objective optical system onto the workpiece.

1 is a schematic configuration diagram showing an example of an optical processing apparatus according to an embodiment of the present invention; FIG. 2 is a block diagram showing a configuration of the optical processing apparatus. FIG. FIG. 2 is a schematic diagram showing a processing optical system, a deflection optical system, and an objective optical system. FIG. 2 is a perspective view showing a processed shot area. FIG. 2 is a perspective view showing a measurement shot area. 1A to 1C are schematic diagrams showing the cross-sectional shape of a processing beam before and after correction. 11 is a cross-sectional view showing a state in which a mapping tool is attached to a stage of an optical processing apparatus. FIG. FIG. 2 is a cross-sectional view showing an example of a map tool. 3 is a flowchart showing an optical processing method according to the present embodiment. FIG. 1 is a cross-sectional view showing an example of a light receiving device.

Below, a preferred embodiment of the present invention will be described. First, the optical processing device according to this embodiment will be described with reference to Figures 1 and 2. In this embodiment, the directions indicated by the arrows in Figure 1 may be referred to as the X-axis direction, the Y-axis direction, and the Z-axis direction, respectively. Furthermore, the rotation direction around the X-axis, the Y-axis, and the Z-axis may be referred to as the θX direction, the θY direction, and the θZ direction, respectively. For ease of explanation, the X-axis direction and the Y-axis direction are each assumed to be horizontal directions, and the Z-axis direction is assumed to be vertical.

As shown in Figures 1 and 2, the optical processing apparatus SYS according to this embodiment includes a processing unit 1, a control unit 2, and a housing 3. The housing 3 is formed in a box shape having an internal space SP. The internal space SP of the housing 3 may be purged with a purge gas (i.e., gas) including an inert gas such as nitrogen gas or argon gas, or CDA (Clean Dry Air), or it may not be purged with a purge gas. In addition, the internal space SP of the housing 3 may be evacuated, or it may not be evacuated. At least a portion of the processing unit 1 is accommodated in the internal space SP of the housing 3.

The processing unit 1 is capable of processing the workpiece W, which is the object to be processed (which may also be referred to as the base material), under the control of the control unit 2. The material of the workpiece W may be, for example, a metal, an alloy (e.g., duralumin, etc.), a semiconductor (e.g., silicon), or a resin. The material of the workpiece W may also be a composite material such as CFRP (Carbon Fiber Reinforced Plastic), paint (one example being a paint layer applied to a substrate), glass, or any other material.

The processing unit 1 irradiates the workpiece W with a processing beam EL in order to process the workpiece W. The processing beam EL may be referred to as processing light. In this embodiment, the processing beam EL is a laser beam. However, the processing beam EL may be a type of light beam other than a laser beam. The wavelength of the processing beam EL is set to, for example, 517 nm (or 515 nm), but may be any wavelength as long as it is possible to process the workpiece W by irradiating it. In other words, the wavelength of the processing beam EL may be a wavelength of visible light or a wavelength of invisible light (for example, at least one of infrared light, ultraviolet light, and extreme ultraviolet light). The processing beam EL may or may not include pulsed light.

The processing unit 1 may perform additional processing on the workpiece W. That is, the processing unit 1 may perform additional processing to form a shaped object on the workpiece W. The processing unit 1 may perform removal processing on the workpiece W. That is, the processing unit 1 may perform removal processing to remove a part of the workpiece W. The processing unit 1 may perform marking processing to form a desired mark on the surface of the workpiece W. The processing unit 1 may perform peening processing to change the characteristics of the surface of the workpiece W. The processing unit 1 may perform peeling processing to peel off the surface of the workpiece W. The processing unit 1 may perform welding processing to join one workpiece W to another workpiece W. The processing unit 1 may perform cutting processing to cut the workpiece W. The processing unit 1 may perform flattening processing (in other words, remelt processing) to melt the surface of the workpiece W and solidify the melted surface to make the surface closer to a flat surface.

The processing unit 1 may process the workpiece W to form a desired structure on the surface of the workpiece W. However, the processing unit 1 may perform processing other than the processing for forming the desired structure on the surface of the workpiece W. An example of a desired structure is a riblet structure. The riblet structure may include a structure that can reduce the resistance of the surface of the workpiece W to the fluid (particularly, at least one of frictional resistance and turbulent frictional resistance). For this reason, the riblet structure may be formed on a portion of the workpiece W that is installed (in other words, located) in the fluid. Examples of the workpiece W on which a riblet structure is formed include aircraft, windmills, engine turbines, and power generation turbines. When such a riblet structure is formed on the workpiece W, the workpiece W becomes easier to move relative to the fluid. This leads to energy savings because the resistance that hinders the movement of the workpiece W relative to the fluid is reduced. In other words, it becomes possible to manufacture an environmentally friendly workpiece W.

Furthermore, the processing unit 1 can measure the measurement object M under the control of the control unit 2. In order to measure the measurement object M, the processing unit 1 irradiates the measurement object M with a measurement beam ML for measuring the measurement object M. Specifically, the processing unit 1 measures the measurement object M by irradiating the measurement object M with the measurement beam ML and detecting (i.e., receiving) at least a portion of the light returning from the measurement object M irradiated with the measurement beam ML. The light returning from the measurement object M irradiated with the measurement beam ML is light from the measurement object M generated by irradiation with the measurement beam ML. In this embodiment, the light returning from the measurement object M irradiated with the measurement beam ML is referred to as the return beam RL. The return beam RL may also be referred to as return light. The measurement beam ML may also be referred to as measurement light.

The measurement beam ML may be any type of light as long as it is capable of measuring the measurement object M by irradiating it on the measurement object M. In this embodiment, the description will be given using an example in which the measurement beam ML is laser light. However, the measurement beam ML may be a type of light other than laser light. The wavelength of the measurement beam ML is set to, for example, 1550 nm, but may be any wavelength as long as it is capable of measuring the measurement object M by irradiating it on the measurement object M. In other words, the wavelength of the measurement beam ML may be the wavelength of visible light or the wavelength of invisible light (for example, at least one of infrared light, ultraviolet light, and extreme ultraviolet light). In addition, the measurement beam ML may include pulsed light (for example, pulsed light having an emission time of picoseconds or less) or may not include pulsed light.

The processing unit 1 may be capable of measuring the characteristics of the measurement object M using the measurement beam ML. The characteristics of the measurement object M may include, for example, at least one of the position of the measurement object M, the shape of the measurement object M, the reflectance of the measurement object M, the transmittance of the measurement object M, the temperature of the measurement object M, and the surface roughness of the measurement object M.

The measurement object M may include, for example, the workpiece W that is processed by the processing unit 1. The measurement object M may include, for example, any object that is placed on the stage 50 described below. The measurement object M may include, for example, the stage 50.

In order to process the workpiece W and measure the measurement object M, the processing unit 1 includes a processing light source 10, a measurement light source 20, a processing head 100, a head drive system 40, a position measurement device 45, a stage 50, a stage drive system 60, and a position measurement device 65.

The processing light source 10 generates a processing beam EL. When the processing beam EL is a laser beam, the processing light source 10 may include, for example, a laser diode. Furthermore, the processing light source 10 may be a light source capable of pulse oscillation. In this case, the processing light source 10 is capable of generating pulsed light as the processing beam EL. Note that the processing light source 10 may be a CW light source that generates a CW (continuous wave).

The measurement light source 20 generates a measurement beam ML. When the measurement beam ML is a laser beam, the measurement light source 20 may include, for example, a laser diode. Furthermore, the measurement light source 20 may be a light source capable of pulse oscillation. In this case, the measurement light source 20 is capable of generating pulsed light as the processing beam EL. Note that the measurement light source 20 may be a CW light source that generates a CW (continuous wave).

The processing head 100 is capable of irradiating the workpiece W with the processing beam EL generated by the processing light source 10 and irradiating the measurement beam ML generated by the measurement light source 20 to the measurement object M. The processing head 100 includes a processing optical system 110, a measurement optical system 130, a synthesis optical system 150, a deflection optical system 160, and an objective optical system 170. The processing head 100 irradiates the processing beam EL (more specifically, a plurality of processing beams EL1 to EL9 described later) to the workpiece W via the processing optical system 110, the synthesis optical system 150, the deflection optical system 160, and the objective optical system 170. The processing head 100 also irradiates the measurement beam ML to the measurement object M via the measurement optical system 130, the synthesis optical system 150, the deflection optical system 160, and the objective optical system 170. The detailed configuration of the processing head 100 will be described later.

The head drive system 40 moves the machining head 100. In other words, the head drive system 40 moves the position of the machining head 100. For this reason, the head drive system 40 may be referred to as a moving device. The head drive system 40 may, for example, move the machining head 100 linearly along a movement axis along at least one of the X-axis direction, the Y-axis direction, and the Z-axis direction. The head drive system 40 may, for example, move the machining head 100 rotationally along at least one of the θX direction, the θY direction, and the θZ direction.

When the head drive system 40 moves the machining head 100, the relative positional relationship between the machining head 100 and the stage 50 (and further the workpiece W placed on the stage 50) changes. As a result, the relative positional relationship between the processing shot area PSA (see FIG. 5 described later) where the machining head 100 performs processing and the workpiece W changes. In other words, the processing shot area PSA moves relative to the workpiece W. The machining unit 1 may process the workpiece W while moving the machining head 100. Specifically, the machining unit 1 may set the processing shot area PSA at a desired position on the workpiece W by moving the machining head 100, and process the desired position on the workpiece W.

Furthermore, when the head drive system 40 moves the processing head 100, the relative positional relationship between the measurement shot area MSA (see FIG. 6 described later) where the processing head 100 performs the measurement and the measurement object M changes. In other words, the measurement shot area MSA moves with respect to the measurement object M. The processing unit 1 may measure the measurement object M while moving the processing head 100. Specifically, the processing unit 1 may set the measurement shot area MSA at a desired position on the measurement object M by moving the processing head 100, and measure the desired position of the measurement object M.

The position measuring device 45 can measure the position of the machining head 100. The position measuring device 45 may include, for example, an interferometer (e.g., a laser interferometer). The position measuring device 45 may include, for example, an encoder (at least one of a linear encoder and a rotary encoder, for example). The position measuring device 45 may include, for example, a potentiometer. When the head drive system 40 uses a stepping motor as a drive source, the position measuring device 45 may include, for example, an open-loop control type position detection device. The open-loop control type position detection device is a position detection device that measures the position of the machining head 100 by estimating the amount of movement of the machining head 100 from the integrated value of the number of pulses for driving the stepping motor.

The workpiece W is placed on the stage 50. For this reason, the stage 50 may be referred to as a placement device. Specifically, the workpiece W is placed on a placement surface 51, which is at least a part of the upper surface of the stage 50. The stage 50 is capable of supporting the workpiece W placed on the stage 50. The stage 50 may be capable of holding the workpiece W placed on the stage 50. In this case, the stage 50 may be equipped with at least one of a mechanical chuck, an electrostatic chuck, a vacuum chuck, and the like, in order to hold the workpiece W. Also, a jig for holding the workpiece W may hold the workpiece W, and the stage 50 may hold the jig that holds the workpiece W. Alternatively, the stage 50 may not hold the workpiece W placed on the stage 50. In this case, the workpiece W may be placed on the stage 50 without being clamped.

The stage drive system 60 moves the stage 50. In other words, the stage drive system 60 moves the position of the stage 50. For this reason, the stage drive system 60 may be referred to as a moving device. The stage drive system 60 may, for example, move the stage 50 linearly along a movement axis along at least one of the X-axis direction, the Y-axis direction, and the Z-axis direction. The stage drive system 60 may, for example, move the stage 50 rotationally along at least one of the θX direction, the θY direction, and the θZ direction.

When the stage drive system 60 moves the stage 50, the relative positional relationship between the processing head 100 and the stage 50 (and further the workpiece W placed on the stage 50) changes. As a result, the relative positional relationship between the processing shot area PSA (see FIG. 5 described later) where the processing head 100 performs processing and the workpiece W changes. In other words, the processing shot area PSA moves relative to the workpiece W. The processing unit 1 may process the workpiece W while moving the stage 50. Specifically, the processing unit 1 may set the processing shot area PSA at a desired position on the workpiece W by moving the stage 50, and process the desired position on the workpiece W.

Furthermore, when the stage drive system 60 moves the stage 50, the relative positional relationship between the measurement shot area MSA (see FIG. 6 described later) where the processing head 100 performs the measurement and the measurement object M changes. In other words, the measurement shot area MSA moves with respect to the measurement object M. The processing unit 1 may measure the measurement object M while moving the stage 50. Specifically, the processing unit 1 may set the measurement shot area MSA at a desired position on the measurement object M by moving the stage 50, and measure the desired position of the measurement object M.

The position measuring device 65 can measure the position of the stage 50. The position measuring device 65 may include, for example, an interferometer (e.g., a laser interferometer). The position measuring device 65 may include, for example, an encoder (at least one of a linear encoder and a rotary encoder, for example). The position measuring device 65 may include, for example, a potentiometer. When the stage drive system 60 uses a stepping motor as a drive source, the position measuring device 65 may include, for example, an open-loop control type position detection device. The open-loop control type position detection device is a position detection device that measures the position of the stage 50 by estimating the amount of movement of the stage 50 from the integrated value of the number of pulses for driving the stepping motor.

The control unit 2 controls the operation of the processing unit 1. For example, the control unit 2 may control the operation of the processing head 100 provided in the processing unit 1. For example, the control unit 2 may control the operation of at least one of the processing optical system 110, the measurement optical system 130, the synthesis optical system 150, the deflection optical system 160, and the objective optical system 170 provided in the processing head 100. For example, the control unit 2 may control the operation of the head drive system 40 provided in the processing unit 1 (for example, the movement of the processing head 100). For example, the control unit 2 may control the operation of the stage drive system 60 provided in the processing unit 1 (for example, the movement of the stage 50).

The control unit 2 may control the operation of the processing unit 1 based on the measurement results of the measurement object M by the processing unit 1. Specifically, the control unit 2 may generate measurement data of the measurement object M (e.g., data related to at least one of the position and shape of the measurement object M) based on the measurement results of the measurement object M, and control the operation of the processing unit 1 based on the generated measurement data. For example, the control unit 2 may generate measurement data of at least a part of the workpiece W based on the measurement results of the workpiece W, which is an example of the measurement object M (e.g., calculate at least one of the position and shape of at least a part of the workpiece W), and control the operation of the processing unit 1 to process the workpiece W based on the measurement data.

The control unit 2 may include, for example, a calculation device and a storage device. The calculation device may include, for example, at least one of a CPU (Central Processing Unit) and a GPU (Graphics Processing Unit). The storage device may include, for example, a memory. The control unit 2 functions as a device that controls the operation of the machining unit 1 by the calculation device executing a computer program. This computer program is a computer program for making the calculation device perform (i.e., execute) the operation to be performed by the control unit 2, which will be described later. In other words, this computer program is a computer program for making the control unit 2 function so as to make the machining unit 1 perform the operation to be described later. The computer program executed by the calculation device may be recorded in a storage device (i.e., a recording medium) included in the control unit 2, or may be recorded in any storage medium (e.g., a hard disk or a semiconductor memory) built into the control unit 2 or that can be externally attached to the control unit 2. Alternatively, the calculation device may download the computer program to be executed from a device external to the control unit 2 via a network interface.

The control unit 2 does not have to be provided inside the processing unit 1. For example, the control unit 2 may be provided outside the processing unit 1 as a server or the like. In this case, the control unit 2 and the processing unit 1 may be connected by a wired and/or wireless network (or a data bus and/or a communication line). As the wired network, for example, a network using a serial bus type interface represented by at least one of IEEE1394, RS-232x, RS-422, RS-423, RS-485, and USB may be used. As the wired network, a network using a parallel bus type interface may be used. As the wired network, a network using an interface compliant with Ethernet (registered trademark) represented by at least one of 10BASE-T, 100BASE-TX, and 1000BASE-T may be used. As the wireless network, a network using radio waves may be used. An example of a network using radio waves is a network conforming to IEEE802.1x (for example, at least one of a wireless LAN and Bluetooth (registered trademark)). A network using infrared rays may be used as a wireless network. A network using optical communication may be used as a wireless network. In this case, the control unit 2 and the processing unit 1 may be configured to be able to transmit and receive various information via the network. The control unit 2 may also be able to transmit information such as commands and control parameters to the processing unit 1 via the network. The processing unit 1 may be equipped with a receiving device that receives information such as commands and control parameters from the control unit 2 via the network. The processing unit 1 may be equipped with a transmitting device (i.e., an output device that outputs information to the control unit 2) that transmits information such as commands and control parameters to the control unit 2 via the network. Alternatively, a first control device that performs a part of the processing performed by the control unit 2 may be provided inside the processing unit 1, while a second control device that performs another part of the processing performed by the control unit 2 may be provided outside the processing unit 1.

In the control unit 2, a computation model that can be constructed by machine learning may be implemented by the computation device executing a computer program. An example of a computation model that can be constructed by machine learning is, for example, a computation model including a neural network (so-called artificial intelligence (AI)). In this case, learning of the computation model may include learning of parameters of the neural network (for example, at least one of weights and biases). The control unit 2 may use the computation model to control the operation of the machining unit 1. In other words, the operation of controlling the operation of the machining unit 1 may include the operation of controlling the operation of the machining unit 1 using the computation model. Note that the control unit 2 may be implemented with a computation model that has already been constructed by offline machine learning using teacher data. In addition, the computation model implemented in the control unit 2 may be updated by online machine learning on the control unit 2. Alternatively, the control unit 2 may control the operation of the machining unit 1 using a computation model implemented in a device external to the control unit 2 (i.e., a device provided outside the machining unit 1) in addition to or instead of the computation model implemented in the control unit 2.

Note that the recording medium for recording the computer program executed by the control unit 2 may be at least one of the following: CD-ROM, CD-R, CD-RW, flexible disk, MO, DVD-ROM, DVD-RAM, DVD-R, DVD+R, DVD-RW, DVD+RW, optical disks such as Blu-ray (registered trademark), magnetic media such as magnetic tape, magneto-optical disk, semiconductor memory such as USB memory, and any other medium capable of storing a program. The recording medium may include a device capable of recording a computer program (for example, a general-purpose device or a dedicated device in which a computer program is implemented in a state in which it can be executed in at least one of the forms of software and firmware, etc.). Furthermore, each process or function included in the computer program may be realized by a logical processing block realized in the control unit 2 by the control unit 2 (i.e., a computer) executing the computer program, or may be realized by hardware such as a predetermined gate array (FPGA (Field Programmable Gate Array), ASIC (Application Specific Integrated Circuit)) provided in the control unit 2, or may be realized in a form that combines logical processing blocks and partial hardware modules that realize some elements of the hardware.

[Configuration of processing head]
Next, the processing head 100 will be described with reference to Fig. 3 to Fig. 7. As shown in Fig. 3, a processing beam EL in a linearly polarized state generated by a processing light source 10 is incident on the processing head 100 via an optical transmission member 11 such as an optical fiber. The processing light source 10 may be disposed outside the processing head 100, or may be disposed inside the processing head 100. The processing beam EL incident on the processing head 100 does not have to pass through an optical transmission member 11 such as an optical fiber. The processing head 100 may also be equipped with the processing light source 10.

As described above, the processing head 100 includes the processing optical system 110, the measurement optical system 130, the synthesis optical system 150, the deflection optical system 160, and the objective optical system 170. The processing optical system 110, the deflection optical system 160, and the control unit 2 may be referred to as the optical device 101 (see FIG. 2) or as an optical scanning device. The optical device 101 may include the measurement optical system 130 and the synthesis optical system 150, or may not include the measurement optical system 130 and the synthesis optical system 150. The processing optical system 110 is irradiated with the processing beam EL transmitted by the optical transmission member 11. The processing optical system 110 splits the processing beam EL incident on the processing optical system 110 into multiple processing beams EL1 to EL9 (see FIG. 7 described later) and emits them toward the synthesis optical system 150. The multiple processing beams EL1 to EL9 emitted from the processing optical system 110 are irradiated onto the workpiece W via the synthesis optical system 150, the deflection optical system 160, and the objective optical system 170. In FIG. 3, to avoid complicating the diagram, only the first processing beam EL1 of the multiple processing beams EL1 to EL9 is shown.

As shown in FIG. 3 and FIG. 4, the processing optical system 110 includes a diffractive optical element 111, a conjugate optical system 112, a wavefront changing unit 115, and a relay optical system 125. A linearly polarized processing beam EL transmitted by the optical transmission member 11 is incident on the diffractive optical element 111. The diffractive optical element 111 splits the processing beam EL incident on the diffractive optical element 111 into multiple processing beams (for example, nine processing beams) EL1 to EL9 by the diffraction phenomenon. The diffractive optical element 111 is disposed so as to be insertable and detachable from the optical path from the processing light source 10 (first optical path described later) using a driving device (not shown). At this time, the multiple processing beams from the diffractive optical element 111 may be multiple parallel beams traveling at a predetermined angle with respect to the perpendicular to the grating surface 111a of the diffractive optical element 111. The predetermined angle of the first processing beam EL1 described later may be 0 degrees.

A correction optical system for correcting the anisotropy of the divergence angle (convergence angle) of the processing beam EL may be arranged in the optical path from the processing light source 10 to the diffractive optical element 111. Such a correction optical system may be, for example, a cylinder zoom optical system equipped with a pair of cylindrical lenses with a variable spacing.

As shown in FIG. 7, among the multiple processing beams EL1 to EL9, the processing light located in the center may be referred to as the first processing beam EL1. The processing light separated from the first processing beam EL1 in the +Y direction may be referred to as the second processing beam EL2. The processing light separated from the first processing beam EL1 in the -Y direction may be referred to as the third processing beam EL3. The processing light separated from the first processing beam EL1 in the +X direction may be referred to as the fourth processing beam EL4. The processing light separated from the first processing beam EL1 in the -X direction may be referred to as the fifth processing beam EL5. The processing light separated from the second processing beam EL2 in the +X direction (and the +Y direction from the fourth processing beam EL4) may be referred to as the sixth processing beam EL6. The processing light separated from the second processing beam EL2 in the -X direction (and the +Y direction from the fifth processing beam EL5) may be referred to as the seventh processing beam EL7. The processing light separated from the third processing beam EL3 in the +X direction (and from the fourth processing beam EL4 in the -Y direction) may be referred to as the eighth processing beam EL8. The processing light separated from the third processing beam EL3 in the -X direction (and from the fifth processing beam EL5 in the -Y direction) may be referred to as the ninth processing beam EL9. The grating surface 111a of the diffractive optical element 111 may be referred to as a beam splitting surface.

In the example shown in FIG. 7, multiple processing beams EL1 to EL9 are distributed in a portion of the processing shot area PSA, and these multiple processing beams EL1 to EL9 move within the processing shot area PSA, but multiple processing beams may be distributed throughout the entire processing shot area PSA.

In this embodiment, an example has been shown in which the diffractive optical element 111 divides the incident processing beam EL into nine, but the number of processing beams divided by the diffractive optical element 111 is not limited to nine. The diffractive optical element 111 only needs to divide the incident processing beam into two or more processing beams. In the example shown in FIG. 7, the divided processing beams are arranged in a matrix, but the divided processing beams may be arranged in a single row, i.e., in a single straight line, or in two rows or a cross shape.

3 and 4, the conjugate optical system 112 includes a first optical system 113 having a positive refractive power and a second optical system 114 having a positive refractive power. Here, the first optical system 113 and the second optical system 114 may be composed of one or more lens elements or one or more reflecting elements. The conjugate optical system 112 forms a conjugate position CP that is optically conjugate with the grating surface 111a of the diffractive optical element 111 by the first optical system 113 and the second optical system 114. The variable reflection surface 118 of the deformable mirror 117 that constitutes the wavefront changing unit 115 is disposed at the conjugate position CP that is optically conjugate with the grating surface 111a of the diffractive optical element 111. A plurality of processing beams EL1 to EL9 emitted from the grating surface 111a of the diffractive optical element 111 are incident on the first optical system 113. The front focal position of the first optical system 113 may be located on the grating surface 111a of the diffractive optical element 111. The first optical system 113 makes the directions of travel of the multiple processing beams EL1 to EL9 that pass through the first optical system 113 parallel to each other. The multiple processing beams EL1 to EL9 that pass through the first optical system 113 are incident on the second optical system 114. The front focal position of the second optical system 114 may be located at the rear focal position of the first optical system 113. The second optical system 114 collects the multiple processing beams EL1 to EL9 that pass through the second optical system 114 toward the conjugate position CP, that is, the variable reflecting surface 118 of the deformable mirror 117. When the multiple processing beams EL1 to EL9 from the grating surface 111a of the diffractive optical element 111 are each parallel light, the multiple processing beams EL1 to EL9 that are parallel light are incident on the variable reflecting surface 118 of the deformable mirror 117 at different angles of incidence. Here, the rear focal position of the second optical system 114 may be located at the conjugate position CP (the variable reflecting surface 118 of the deformable mirror 117).

The wavefront changing unit 115 includes a polarizing beam splitter 116, a deformable mirror 117, a beam dumper 119, a first half-wave plate 121, a first quarter-wave plate 122, a second half-wave plate 123, and a second quarter-wave plate 124. The first half-wave plate 121 is disposed between the conjugate optical system 112 and the polarizing beam splitter 116 in the optical path from the processing light source 10 to the polarizing beam splitter 116. Hereinafter, the optical path from the processing light source 10 to the polarizing beam splitter 116 may be referred to as the first optical path. A plurality of processing beams EL1 to EL9 that have passed through the second optical system 114 of the conjugate optical system 112 are incident on the first half-wave plate 121. The multiple processing beams EL1 to EL9 incident on the first half-wave plate 121 pass through the first half-wave plate 121 and enter the polarizing beam splitter 116. The first half-wave plate 121 adjusts the polarization direction of the multiple processing beams EL1 to EL9 so that the multiple processing beams EL1 to EL9 incident on the polarizing beam splitter 116 become s-polarized (s-polarized with respect to the polarization separation surface of the polarizing beam splitter 116). The first half-wave plate 121 may also be referred to as a polarization direction adjustment member.

The polarizing beam splitter 116 can split the light incident along the first optical path (optical path from the processing light source 10 to the polarizing beam splitter 116) into light traveling along a second optical path that intersects with the first optical path, typically perpendicular to the first optical path, and light traveling along a third optical path that is an extension of the first optical path. The polarizing beam splitter 116 can also split the light incident along the second optical path (light returning from the second optical path) into light traveling along the first optical path and light traveling along a fourth optical path that is an extension of the second optical path. In the second optical path, a first quarter-wave plate 122 and a deformable mirror 117 are arranged in this order from the polarizing beam splitter 116 side. A beam damper 119 is arranged in the third optical path. In the fourth optical path, a second half-wave plate 123, a second quarter-wave plate 124, and a relay optical system 125 are arranged in this order from the polarizing beam splitter 116 side.

The multiple processing beams EL1 to EL9 that have passed through the first half-wave plate 121 are incident on the polarizing beam splitter 116. The polarizing beam splitter 116 reflects the multiple processing beams EL1 to EL9 (s-polarized) that are incident along the first optical path toward the first quarter-wave plate 122 (i.e., the deformable mirror 117) that is arranged in the second optical path. The first quarter-wave plate 122 is arranged between the polarizing beam splitter 116 and the deformable mirror 117 in the second optical path. The multiple processing beams EL1 to EL9 (s-polarized) that have been reflected by the polarizing beam splitter 116 become circularly polarized when they pass through the first quarter-wave plate 122.

The deformable mirror 117 is incident on a plurality of processing beams EL1 to EL9 (circularly polarized) that are reflected by the polarizing beam splitter 116 and pass through the first quarter-wave plate 122. The deformable mirror 117 has a deformable variable reflecting surface 118 and a number of actuators connected to the variable reflecting surface 118, and is capable of changing the shape of the variable reflecting surface 118 in response to a control signal from the control unit 2. As the deformable mirror 117, for example, a deformable mirror disclosed in U.S. Pat. No. 5,521,747, U.S. Pat. No. 7,224,504, U.S. Pat. No. 7,336,412, U.S. Pat. No. 7,708,415, U.S. Patent Application Publication No. 2002/0109894, etc. may be used. The deformable mirror 117 reflects the multiple processing beams EL1 to EL9 incident on the deformable mirror 117 at the variable reflecting surface 118, and causes the multiple processing beams EL1 to EL9 to be incident on the polarizing beam splitter 116 via the first quarter-wave plate 122. At this time, the deformable mirror 117 can change the wavefront of each beam cross section of the multiple processing beams EL1 to EL9 emitted from the variable reflecting surface 118 by deforming the variable reflecting surface 118. Here, the beam cross section may be a surface that crosses the beam traveling direction, typically a surface that is perpendicular to the beam traveling direction. The deformable mirror 117 may be referred to as a wavefront changing member. The variable reflecting surface 118 may be referred to as a wavefront changing surface.

The variable reflecting surface 118 of the deformable mirror 117 is optically conjugate with the grating surface 111a of the diffractive optical element 111. The multiple processing beams EL1 to EL9 emitted from the grating surface 111a of the diffractive optical element 111 are each converted into parallel light by the first optical system 113 and the second optical system 114 of the conjugate optical system 112, and are incident on the variable reflecting surface 118 of the deformable mirror 117 so as to converge.

Furthermore, the multiple processing beams EL1 to EL9 (circularly polarized) reflected by the variable reflecting surface 118 of the deformable mirror 117 become p-polarized (p-polarized with respect to the polarization separation surface of the polarizing beam splitter 116) when they pass through the first quarter-wave plate 122 again. The polarizing beam splitter 116 transmits the multiple processing beams EL1 to EL9 (p-polarized) incident along the second optical path toward the second half-wave plate 123 (i.e., the relay optical system 125) arranged in the fourth optical path. As a result, the multiple processing beams EL1 to EL9 reflected by the variable reflecting surface 118 of the deformable mirror 117 are emitted along the fourth optical path via the polarizing beam splitter 116. The multiple processing beams EL1 to EL9 (p-polarized) emitted along the fourth optical path become circularly polarized when they pass through the second half-wave plate 123 and the second quarter-wave plate 124. The multiple processing beams EL1 to EL9 that pass through the second quarter-wave plate 124 are incident on the relay optical system 125.

In the above example, the deformable mirror 117 is disposed on the side where the multiple processing beams EL1 to EL9 incident on the polarizing beam splitter 116 are reflected, but the deformable mirror 117 may also be disposed on the side where the multiple processing beams EL1 to EL9 incident on the polarizing beam splitter 116 are transmitted. In this case, the multiple processing beams EL1 to EL9 incident on the polarizing beam splitter 116 may be p-polarized with respect to the polarization separation surface of the polarizing beam splitter 116.

Furthermore, the processing beam (return light) returning from the workpiece W toward the polarizing beam splitter 116 becomes linearly polarized when it passes through the second 1/4 wavelength plate 124 after passing through the relay optical system 125. The processing beam from the workpiece W that has passed through the second 1/4 wavelength plate 124 is incident on the second 1/2 wavelength plate 123. The processing beam from the workpiece W that has entered the second 1/2 wavelength plate 123 passes through the second 1/2 wavelength plate 123 and enters the polarizing beam splitter 116. The second 1/2 wavelength plate 123 adjusts the polarization direction of the processing beam from the workpiece W so that the processing beam from the workpiece W that enters the polarizing beam splitter 116 becomes s-polarized. The second 1/2 wavelength plate 123 may be referred to as a second polarization direction adjustment member. The polarizing beam splitter 116 reflects the processing beam (s-polarized) from the workpiece W that enters along the fourth optical path toward the beam damper 119 arranged on the third optical path.

The beam damper 119 blocks the processing beam (s-polarized light) from the workpiece W that is reflected by the polarizing beam splitter 116. This allows the beam damper 119 to absorb the processing beam (return light) from the workpiece W. The beam damper 119 is also called a beam trap, beam diffuser, or beam pocket.

The relay optical system 125 includes a first relay lens 126 having a positive refractive power and a second relay lens 127 having a positive refractive power. The relay optical system 125 optically conjugates the variable reflecting surface 118 of the deformable mirror 117 and the galvanometer mirror 161 of the deflection optical system 160 with the first relay lens 126 and the second relay lens 127. In other words, the relay optical system 125 optically conjugates the variable reflecting surface 118 of the deformable mirror 117 and the entrance pupil PU of the objective optical system 170 with the first relay lens 126 and the second relay lens 127. A plurality of processing beams EL1 to EL9 that have passed through the second 1/4 wavelength plate 124 are incident on the first relay lens 126. The first relay lens 126 makes the traveling directions of the plurality of processing beams EL1 to EL9 that pass through the first relay lens 126 parallel to each other. The second relay lens 127 is incident on the multiple processing beams EL1 to EL9 that have passed through the first relay lens 126. The second relay lens 127 collects the multiple processing beams EL1 to EL9 that have passed through the second relay lens 127 toward the galvanometer mirror 161 of the deflection optical system 160, i.e., the entrance pupil PU of the objective optical system 170. The first relay lens 126 and the second relay lens 127 may be composed of one or more lens elements, one or more reflecting elements, etc.

As shown in FIG. 3, the multiple processing beams EL1 to EL9 emitted from the processing optical system 110 (second relay lens 127) are incident on the synthesis optical system 150. The synthesis optical system 150 emits the multiple processing beams EL1 to EL9 incident on the synthesis optical system 150 toward the deflection optical system 160. The synthesis optical system 150 includes a dichroic mirror 151, a mirror 152, and a correction wavefront measuring device 153.

The dichroic mirror 151 reflects the multiple processing beams EL1 to EL9 emitted from the processing optical system 110 toward the mirror 152. Note that the dichroic mirror 151 passes a portion of the (unsplit) processing beam EL emitted from the processing optical system 110 when the diffractive optical element 111 is removed from the first optical path, toward the corrective wavefront measuring device 153 as leakage light. The mirror 152 reflects the multiple processing beams EL1 to EL9 reflected by the dichroic mirror 151 toward the deflection optical system 160.

A part of the processing beam EL that passes through the dichroic mirror 151 with the diffractive optical element 111 removed from the first optical path is incident on the corrective wavefront measuring device 153. Here, if the amount of light of the processing beam EL as leakage light passing through the dichroic mirror 151 is too large, a light attenuation member may be disposed between the dichroic mirror 151 and the corrective wavefront measuring device 153. The amount of light attenuation by this light attenuation member may be changeable. The corrective wavefront measuring device 153 is disposed at a position where the pupil of the corrective wavefront measuring device 153 is optically conjugate with the variable reflecting surface 118 of the deformable mirror 117. The corrective wavefront measuring device 153 is configured using a Shack-Hartmann sensor. The corrective wavefront measuring device 153 measures the phase distribution of the wavefront of the light (i.e., the processing beam EL) that is incident on the corrective wavefront measuring device 153. The measurement result of the phase distribution of the wavefront by the corrective wavefront measuring device 153 is output to the control unit 2. In addition, the correction wavefront measuring device 153 may be incident with multiple processing beams EL that have passed through the dichroic mirror 151 with the diffractive optical element 111 inserted in the first optical path. In this case, multiple light spot images are formed on the light detection surface of the photodetector of the correction wavefront measuring device 153, and when the separation distance between these multiple light spot images is small and they can essentially be considered as one spot, the average wavefront of the multiple processing beams EL can be measured. Also, when the separation distance between the multiple light spot images is large and each light spot image can be separated on the light detection surface, the wavefront of each of the multiple processing beams EL can be measured.

When the separation distance of the multiple light spot images is intermediate between the above two, a light blocking member that passes one of the multiple processing beams EL and blocks the others may be provided at a position where the multiple processing beams EL from the diffractive optical element 111 are spatially separated, typically a position between the first optical system 113 and the second optical system 114 in the conjugate optical system 112, or a position between the first relay lens 126 and the second relay lens 127 in the relay optical system 125, and the wavefronts of the multiple processing beams EL may be measured one by one. In this case, the light blocking member may be movable so that the processing beam EL to be passed can be selected. In addition, a member that limits the incident angle of the processing beam incident on each array, for example, a partition-like member along the boundary of each array, may be provided on the incident side of the lens array or DOE array, which is the wavefront division member of the Shack-Hartmann sensor. In this case, multiple partition-like members may be prepared for each incident angle to be limited, and the wavefronts of each processing beam may be measured one by one by replacing the multiple partition-like members.

The deflection optical system 160 is incident on the multiple processing beams EL1 to EL9 emitted from the synthesis optical system 150. The deflection optical system 160 emits the multiple processing beams EL1 to EL9 incident on the deflection optical system 160 toward the objective optical system 170. The deflection optical system 160 is equipped with a galvanometer mirror 161 arranged at the position of the entrance pupil PU of the objective optical system 170. The galvanometer mirror 161 deflects the multiple processing beams EL1 to EL9 from the synthesis optical system 150 (i.e., changes the traveling direction of the multiple processing beams EL1 to EL9). By deflecting the multiple processing beams EL1 to EL9, the galvanometer mirror 161 changes the irradiation position on the workpiece W (in a plane along the XY plane) of the multiple processing beams EL1 to EL9 irradiated onto the workpiece W via the objective optical system 170. The galvanometer mirror 161 may also be referred to as a deflection member. Furthermore, the deflection member is not limited to the galvanometer mirror 161, but may be a polygon mirror or a resonant mirror.

The galvanometer mirror 161 includes an X-scanning mirror 162X and a Y-scanning mirror 162Y. The X-scanning mirror 162X is a deflection mirror having a reflecting surface 163X that can rotate around the Y-axis. Here, the Y-axis may be referred to as the first axis. The X-scanning mirror 162X deflects the multiple processing beams EL1 to EL9 so as to change the irradiation positions of the multiple processing beams EL1 to EL9 on the workpiece W along the X-axis direction. The Y-scanning mirror 162Y is a deflection mirror having a reflecting surface 163Y that can rotate around the X-axis. Here, the X-axis may be referred to as the second axis that intersects with the first axis. The Y-scanning mirror 162Y deflects the multiple processing beams EL1 to EL9 so as to change the irradiation positions of the multiple processing beams EL1 to EL9 on the workpiece W along the Y-axis direction. The entrance pupil PU of the objective optical system 170 may be located between the X-scanning mirror 162X and the Y-scanning mirror 162Y in the galvanometer mirror 161. The reflecting

surfaces

163X and 163Y of the X-scanning mirror 162X and the Y-scanning mirror 162Y may be referred to as beam deflection surfaces.

The galvanometer mirror 161 allows the multiple processing beams EL1 to EL9 to scan the processing shot area PSA, which is determined based on the processing head 100. An example of the processing shot area PSA is shown in FIG. 5. As shown in FIG. 5, the processing shot area PSA indicates the area (range) where processing is performed by the processing head 100 with the positional relationship between the processing head 100 and the workpiece W fixed. For example, the processing shot area PSA is set to coincide with the scanning range of the multiple processing beams EL1 to EL9 deflected by the galvanometer mirror 161 with the positional relationship between the processing head 100 and the workpiece W fixed, or to be an area narrower than the scanning range. Note that in FIG. 5, only the first processing beam EL1 of the multiple processing beams EL1 to EL9 is shown to prevent the diagram from becoming complicated. As described above, the processing head 100 is moved by the head drive system 40, so that the processing shot area PSA can move relatively on the surface of the workpiece W. In addition, the stage 50 is moved by the stage drive system 60, so that the processing shot area PSA can move relatively over the surface of the workpiece W.

The objective optical system 170 includes an fθ lens 171. The fθ lens 171 is incident on the multiple processing beams EL1 to EL9 emitted from the deflection optical system 160. The fθ lens 171 irradiates the multiple processing beams EL1 to EL9 emitted from the deflection optical system 160 in parallel with each other onto the workpiece W. Specifically, the fθ lens 171 emits the multiple processing beams EL1 to EL9 in a direction along the optical axis of the fθ lens 171. The fθ lens 171 also focuses the multiple processing beams EL1 to EL9 onto the workpiece W. Since the fθ lens 171 is a workpiece-side telecentric optical system, the multiple processing beams EL1 to EL9 emitted from the fθ lens 171 travel in a direction along the optical axis of the fθ lens 171 in a parallel state with each other, and are focused and irradiated onto the workpiece W. The fθ lens 171 may be an optical system that is non-telecentric on the workpiece side.

The processing optical system 110, the measurement optical system 130, the synthesis optical system 150, and the deflection optical system 160 may be housed in a first head housing 106 in the processing head 100. On the other hand, the objective optical system 170 may be housed in a second head housing 107 that is different from the first head housing 106. The second head housing 107 housing the objective optical system 170 may be configured to be detachable from the first head housing 106.

As described above, the galvanometer mirror 161 of the deflection optical system 160 allows the multiple processing beams EL1 to EL9 to scan the processing shot area PSA, thereby improving the processing speed of the workpiece W. It is desirable that the cross-sectional shape of the multiple processing beams EL1 to EL9 irradiated onto the processing shot area PSA is circular. However, due to astigmatism and the like that occurs in the objective optical system 170, the cross-sectional shape of the processing beams passing through the periphery of the objective optical system 170 (fθ lens 171) is easily deformed. For example, as illustrated in the diagram before correction in FIG. 7, even if the cross-sectional shape of the first processing beam EL1 is circular, the cross-sectional shapes of the second to ninth processing beams EL2 to EL9 located around the first processing beam EL1 are easily deformed into an elliptical shape rather than a circular shape.

In this embodiment, the deformable mirror 117 is capable of changing the shape of the wavefront (typically, an equiphase wavefront) at each beam cross section of the multiple processing beams EL1 to EL9 emitted from the variable reflecting surface 118 by deforming the variable reflecting surface 118. Therefore, the deformable mirror 117 is capable of correcting the change in the wavefront at each beam cross section of the multiple processing beams EL1 to EL9 from the objective optical system 170 that occurs with the operation of the galvanometer mirror 161 by deforming the variable reflecting surface 118. In other words, the deformable mirror 117 is capable of correcting the change in the wavefront, particularly the change in the shape of the wavefront, at each beam cross section of the multiple processing beams EL1 to EL9 from the objective optical system 170 that occurs with the movement of the irradiation position of the multiple processing beams EL1 to EL9 irradiated from the objective optical system 170 to the workpiece W. As a result, the deformable mirror 117 can correct the non-rotationally symmetric components of the wavefront in the cross section of each of the multiple processing beams EL1 to EL9 from the objective optical system 170, and make the cross-sectional shapes of each of the multiple processing beams EL1 to EL9 circular, as shown in the post-correction diagram of FIG. 7. The deformable mirror 117 may also be referred to as a correction member.

The deformable mirror 117 may change the focusing positions (in other words, the irradiation positions in the Z-axis direction) of the multiple processing beams EL1 to EL9 focused by the objective optical system 170 toward the workpiece W along the optical axis direction (Z-axis direction) of the objective optical system 170 by deforming the variable reflecting surface 118 to change the radius of curvature of the variable reflecting surface 118. This makes it possible to change the irradiation positions (focusing positions) of the multiple processing beams EL1 to EL9 in the Z-axis direction at high speed. The deformable mirror 117 may also correct the non-rotationally symmetric components of the wavefront in each beam cross section of the multiple processing beams EL1 to EL9 from the objective optical system 170 by deforming the variable reflecting surface 118 when changing the irradiation positions (focusing positions) of the multiple processing beams EL1 to EL9 in the Z-axis direction. This makes it possible to maintain the cross-sectional shapes of the multiple processing beams EL1 to EL9 in a circular shape when changing the irradiation positions (focusing positions) of the multiple processing beams EL1 to EL9 in the Z-axis direction.

In this embodiment, since the multiple processing beams EL1 to EL9 are distributed in a portion of the processing shot area PSA, it is possible to make the cross-sectional shape of each of the multiple processing beams EL1 to EL9 circular even if the wavefront shape of each beam cross section of the multiple processing beams EL1 to EL9 is uniformly corrected. Here, in order to improve the cross-sectional shape of each processing beam on the workpiece W by uniformly correcting the wavefront shape of each beam cross section, the area in which the multiple processing beams are distributed (the area determined by the outer edge connecting the outermost beam positions of the multiple processing beams) may be 1/100 or less, 1/200 or less, or 1/800 or less of the area of the processing shot area PSA.

The measurement beam ML generated by the measurement light source 20 is incident on the processing head 100 via an optical transmission member 21 such as an optical fiber. The measurement light source 20 may be disposed outside the processing head 100, or may be disposed inside the processing head 100. The measurement beam ML incident on the processing head 100 does not have to pass through an optical transmission member 21 such as an optical fiber. The optical transmission member 21 may be a polarization-preserving optical fiber.

The measurement light source 20 may include an optical comb light source. An optical comb light source is a light source that can generate light containing frequency components that are evenly spaced on the frequency axis (this light is also called an optical frequency comb) as pulsed light. In this case, the measurement light source 20 emits a light beam that contains pulsed light of frequency components that are evenly spaced on the frequency axis as the measurement beam ML. However, the measurement light source 20 may include a light source other than the optical comb light source.

In the example shown in FIG. 3, the optical processing device SYS includes a first measurement light source 20a and a second measurement light source 20b as the measurement light source 20. The multiple

measurement light sources

20a, 20b each emit multiple measurement beams ML that are phase-synchronized and coherent with each other. For example, the multiple

measurement light sources

20a, 20b may have different oscillation frequencies. Therefore, the multiple measurement beams ML emitted from the multiple

measurement light sources

20a, 20b become light beams that include multiple pulsed lights with different pulse frequencies (for example, the number of pulsed lights per unit time, which is the reciprocal of the emission period of the pulsed lights). However, the optical processing device SYS may also include a single measurement light source 20.

The measurement optical system 130 is incident on the measurement optical system 130, which is transmitted by the optical transmission member 21. The measurement optical system 130 emits the measurement beam ML incident on the measurement optical system 130 toward the synthesis optical system 150. The measurement beam ML emitted from the measurement optical system 130 is irradiated onto the measurement object M via the synthesis optical system 150, the deflection optical system 160, and the objective optical system 170. The measurement optical system 130 includes a first mirror 131, a first beam splitter 132, a second beam splitter 133, a third beam splitter 134, a second mirror 135, a third mirror 136, a galvanometer mirror 137, a first detector 141, and a second detector 142.

The measurement beam ML emitted from the measurement light source 20 is incident on the first beam splitter 132. Specifically, the measurement beam ML emitted from the first measurement light source 20a (hereinafter referred to as "measurement beam ML1") is incident on the first beam splitter 132. The measurement beam ML emitted from the second measurement light source 20b (hereinafter referred to as "measurement beam ML2") is incident on the first beam splitter 132 via the first mirror 131. The first beam splitter 132 emits the measurement beam ML1 and measurement beam ML2 incident on the first beam splitter 132 toward the second beam splitter 133.

The second beam splitter 133 reflects a portion of the measurement beam ML1 incident on the second beam splitter 133, namely, measurement beam ML1-1, toward the first detector 141. The second beam splitter 133 passes another portion of the measurement beam ML1 incident on the second beam splitter 133, namely, measurement beam ML1-2, toward the third beam splitter 134. The second beam splitter 133 reflects a portion of the measurement beam ML2 incident on the second beam splitter 133, namely, measurement beam ML2-1, toward the first detector 141. The second beam splitter 133 passes another portion of the measurement beam ML2 incident on the second beam splitter 133, namely, measurement beam ML2-2, toward the third beam splitter 134.

The measurement beam ML1-1 and measurement beam ML2-1 reflected by the second beam splitter 133 are incident on the first detector 141. The first detector 141 detects interference light generated by the interference between the measurement beam ML1-1 and the measurement beam ML2-1. Specifically, the first detector 141 detects the interference light by receiving it. The detection result of the first detector 141 is output to the control unit 2.

The measurement beam ML1-2 and the measurement beam ML2-2 that pass through the second beam splitter 133 are incident on the third beam splitter 134. The third beam splitter 134 reflects at least a portion of the measurement beam ML1-2 that is incident on the third beam splitter 134 toward the second mirror 135. The third beam splitter 134 transmits at least a portion of the measurement beam ML2-2 that is incident on the third beam splitter 134 toward the third mirror 136.

The measurement beam ML1-2 reflected by the third beam splitter 134 is incident on the second mirror 135. The measurement beam ML1-2 incident on the second mirror 135 is reflected by the reflecting surface of the second mirror 135 (the reflecting surface is also called the reference surface). That is, the second mirror 135 emits the measurement beam ML1-2 incident on the second mirror 135 as the reflected light, measurement beam ML1-3, toward the third beam splitter 134. The measurement beam ML1-3 reflected light from the second mirror 135 is also called the reference light. The measurement beam ML1-3 emitted from the second mirror 135 is incident on the third beam splitter 134. The third beam splitter 134 reflects the measurement beam ML1-3 incident on the third beam splitter 134 toward the second beam splitter 133. The measurement beam ML1-3 reflected by the second beam splitter 133 is incident on the first beam splitter 132. The first beam splitter 132 reflects the measurement beam ML1-3 incident on the first beam splitter 132 toward the second detector 142.

Meanwhile, the measurement beam ML2-2 that passes through the third beam splitter 134 is incident on the third mirror 136. The third mirror 136 reflects the measurement beam ML2-2 that is incident on the third mirror 136 toward the galvanometer mirror 137.

The galvanometer mirror 137 deflects the measurement beam ML2-2 (i.e., changes the traveling direction of the measurement beam ML2-2). By deflecting the measurement beam ML2-2, the galvanometer mirror 137 changes the irradiation position on the workpiece W (within a plane along the XY plane) of the measurement beam ML2-2 that is irradiated onto the workpiece W via the objective optical system 170.

The galvanometer mirror 137 includes an X-scanning mirror 138X and a Y-scanning mirror 138Y. The X-scanning mirror 138X is a deflection mirror with a reflective surface that can rotate around the Y-axis. The X-scanning mirror 138X deflects the measurement beam ML2-2 so as to change the irradiation position of the measurement beam ML2-2 on the workpiece W along the X-axis direction. The Y-scanning mirror 138Y is a deflection mirror with a reflective surface that can rotate around the X-axis. The Y-scanning mirror 138Y deflects the measurement beam ML2-2 so as to change the irradiation position of the measurement beam ML2-2 on the workpiece W along the Y-axis direction.

The measurement beam ML2-2 emitted from the measurement optical system 130 (galvanometer mirror 137) enters the synthesis optical system 150. The wavelength of the measurement beam ML (measurement beam ML2-2) is different from the wavelength of the processing beam EL (multiple processing beams EL1 to EL9). The dichroic mirror 151 of the synthesis optical system 150 passes the measurement beam ML2-2 emitted from the measurement optical system 130 toward the mirror 152 of the synthesis optical system 150. The mirror 152 reflects the measurement beam ML2-2 that has passed through the dichroic mirror 151 toward the deflection optical system 160. The measurement beam ML2-2 from the third mirror 136 (or the third beam splitter 134) may be directly incident on the synthesis optical system 150 without providing the galvanometer mirror 137.

As described above, in addition to the measurement beam ML2-2, multiple processing beams EL1 to EL9 are incident on the dichroic mirror 151 of the combining optical system 150. The dichroic mirror 151 outputs the measurement beam ML2-2 and the multiple processing beams EL1 to EL9, which are incident from different directions, in the same direction (i.e., toward the same deflection optical system 160). As a result, in the combining optical system 150, the optical path of the measurement beam ML2-2 merges with the optical paths of the multiple processing beams EL1 to EL9.

The measurement beam ML2-2 emitted from the synthesis optical system 150 enters the deflection optical system 160. The deflection optical system 160 emits the measurement beam ML2-2 incident on the deflection optical system 160 toward the objective optical system 170. The galvanometer mirror 161 of the deflection optical system 160 deflects the measurement beam ML2-2 from the synthesis optical system 150, thereby changing the irradiation position on the measurement object M (within a plane along the XY plane) of the measurement beam ML2-2 that is irradiated onto the workpiece W via the objective optical system 170.

As described above, in addition to the measurement beam ML2-2, multiple processing beams EL1 to EL9 are incident on the galvanometer mirror 161 of the deflection optical system 160. Therefore, both the measurement beam ML2-2 and the multiple processing beams EL1 to EL9 pass through the same galvanometer mirror 161. Therefore, the galvanometer mirror 161 of the deflection optical system 160 can change the irradiation position of the multiple processing beams EL1 to EL9 and the irradiation position of the measurement beam ML2-2 in synchronization (i.e., in conjunction with each other).

As described above, the measurement beam ML2-2 is irradiated onto the measurement object M via the galvanometer mirror 137 of the measurement optical system 130. On the other hand, the multiple processing beams EL1 to EL9 are irradiated onto the workpiece W without passing through the galvanometer mirror 137. Therefore, the galvanometer mirror 137 of the measurement optical system 130 can independently move the irradiation position of the measurement beam ML2-2, regardless of the irradiation positions of the multiple processing beams EL1 to EL9. In other words, the galvanometer mirror 137 of the measurement optical system 130 can change the relative positional relationship between the irradiation positions of the multiple processing beams EL1 to EL9 and the irradiation position of the measurement beam ML2-2.

The measurement beam ML2-2 can scan the measurement shot area MSA, which is determined based on the processing head 100, by at least one of the galvanometer mirror 161 of the deflection optical system 160 and the galvanometer mirror 137 of the measurement optical system 130. An example of the measurement shot area MSA is shown in FIG. 6. As shown in FIG. 6, the measurement shot area MSA indicates the area (range) where the measurement is performed by the processing head 100 with the positional relationship between the processing head 100 and the measurement object M fixed. For example, the measurement shot area MSA is set to coincide with the scanning range of the measurement beam ML2-2 deflected by at least one of the galvanometer mirror 161 of the deflection optical system 160 and the galvanometer mirror 137 of the measurement optical system 130 with the positional relationship between the processing head 100 and the measurement object M fixed, or to be an area narrower than the scanning range. As described above, the measurement shot area MSA can be moved relatively on the surface of the measurement object M by the head drive system 40 moving the processing head 100. In addition, the stage 50 is moved by the stage drive system 60, so that the measurement shot area MSA can be moved relatively on the surface of the measurement object M.

The measurement beam ML2-2 emitted from the deflection optical system 160 enters the objective optical system 170. The fθ lens 171 of the objective optical system 170 irradiates the measurement beam ML2-2 emitted from the deflection optical system 160 onto the measurement object M. Specifically, the fθ lens 171 emits the measurement beam ML2-2 in a direction along the optical axis of the fθ lens 171. The fθ lens 171 also focuses the measurement beam ML2-2 on the measurement object M. As a result, the measurement beam ML2-2 emitted from the fθ lens 171 travels in a direction along the optical axis of the fθ lens 171 and is focused and irradiated onto the measurement object M.

When the measurement object M is irradiated with the measurement beam ML2-2, light resulting from the irradiation of the measurement beam ML2-2 is emitted from the measurement object M. The light emitted from the measurement object M due to the irradiation of the measurement beam ML2-2 may include at least one of the measurement beam ML2-2 reflected by the measurement object M (i.e., reflected light), the measurement beam ML2-2 scattered by the measurement object M (i.e., scattered light), the measurement beam ML2-2 diffracted by the measurement object M (i.e., diffracted light), and the measurement beam ML2-2 transmitted through the measurement object M (i.e., transmitted light).

At least a portion of the light emitted from the measurement object M due to irradiation with the measurement beam ML2-2 enters the objective optical system 170 as a return beam RL. Specifically, of the light emitted from the measurement object M due to irradiation with the measurement beam ML2-2, the light traveling along the optical path of the measurement beam ML2-2 incident on the measurement object M enters the objective optical system 170 as a return beam RL. In this case, the optical path of the measurement beam ML2-2 emitted from the objective optical system 170 and incident on the measurement object M may be the same as the optical path of the return beam RL emitted from the measurement object M and incident on the objective optical system 170. The return beam RL incident on the objective optical system 170 enters the deflection optical system 160 via the fθ lens 171. The return beam RL incident on the deflection optical system 160 enters the synthesis optical system 150 via the galvanometer mirror 161. The return beam RL that is incident on the synthesis optical system 150 is incident on the measurement optical system 130 via the mirror 152 and the dichroic mirror 151. At this time, the dichroic mirror 151 of the synthesis optical system 150 passes the return beam RL that is incident on the dichroic mirror 151 toward the measurement optical system 130.

The return beam RL that passes through the dichroic mirror 151 of the synthesis optical system 150 is incident on the galvanometer mirror 137 of the measurement optical system 130. The galvanometer mirror 137 emits the return beam RL that is incident on the galvanometer mirror 137 toward the third mirror 136. The third mirror 136 reflects the return beam RL that is incident on the third mirror 136 toward the third beam splitter 134. The third beam splitter 134 passes at least a portion of the return beam RL that is incident on the third beam splitter 134 toward the second beam splitter 133. The second beam splitter 133 reflects at least a portion of the return beam RL that is incident on the second beam splitter 133 toward the second detector 142.

As described above, in addition to the return beam RL, the measurement beams ML1-3 are incident on the second detector 142. That is, the return beam RL, which travels toward the second detector 142 via the measurement object M, and the measurement beams ML1-3, which travel toward the second detector 142 without passing through the measurement object M, are incident on the second detector 142. The second detector 142 detects interference light generated by interference between the measurement beams ML1-3 and the return beam RL. Specifically, the second detector 142 detects the interference light by receiving it. The detection result of the second detector 142 is output to the control unit 2.

The control unit 2 acquires the detection results of the first detector 141 and the second detector 142. The control unit 2 is capable of generating measurement data of the measurement object M (e.g., measurement data relating to at least one of the position and the shape of the measurement object M) based on the detection results of the first detector 141 and the detection results of the second detector 142.

Specifically, the control unit 2 can calculate the distance between the processing head 100 and the measurement object M in a direction along the optical path of the measurement beam ML (for example, the Z-axis direction) based on the time difference between the pulsed light of the interference light detected by the second detector 142 and the pulsed light of the interference light detected by the first detector 141. In other words, the control unit 2 can calculate the position of the measurement object M in a direction along the optical path of the measurement beam ML (for example, the Z-axis direction). More specifically, the control unit 2 can calculate the distance between the irradiated portion of the measurement object M irradiated with the measurement beam ML2-2 and the processing head 100. The control unit 2 can calculate the position of the irradiated portion in a direction along the optical path of the measurement beam ML (for example, the Z-axis direction). Furthermore, the control unit 2 can calculate the position of the irradiated portion in a direction intersecting the optical path of the measurement beam ML (for example, at least one of the X-axis direction and the Y-axis direction) based on the driving state of the galvanometer mirror 161 of the deflection optical system 160 and the galvanometer mirror 137 of the measurement optical system 130. As a result, the control unit 2 can generate measurement data that indicates the position of the irradiated portion in a measurement coordinate system based on the processing head 100 (e.g., the position in a three-dimensional coordinate space).

[Map Tool Configuration]
Next, a mapping tool 180 for generating an aberration map, which will be described later, will be described with reference to Fig. 8 and Fig. 9. As shown in Fig. 8, the mapping tool 180 is temporarily attached to the stage 50 when generating an aberration map, which will be described later. As shown in Fig. 9, the mapping tool 180 includes a mapping lens 181, a mapping wavefront measuring device 182, and a housing unit 183.

The housing 183 holds the map lens 181 and the map wavefront measuring device 182. The housing 183 may be placed on the mounting surface 51 of the stage 50 without the workpiece W or measurement object M being placed thereon (see also FIG. 8). The housing 183 may also be removably attached to the side of the stage 50. In either case, the head drive system 40 moves the machining head 100 to align the optical axis of the map lens 181 with the optical axis of the objective optical system 170 (fθ lens 171).

The (unsplit) processing beam EL emitted from the fθ lens 171 of the objective optical system 170 with the diffractive optical element 111 removed from the first optical path is incident on the map lens 181. The map lens 181 optically conjugates the exit pupil of the objective optical system 170 with the pupil of the map wavefront measuring device 182. The map lens 181 collects the processing beam EL that passes through the map lens 181 toward the map wavefront measuring device 182. Note that the map lens 181 may be incident on multiple processing beams EL emitted from the fθ lens 171 of the objective optical system 170 with the diffractive optical element 111 inserted in the first optical path.

The processing beam EL that has passed through the map lens 181 is incident on the map wavefront measuring device 182. The map wavefront measuring device 182 is configured using a Shack-Hartmann sensor. The map wavefront measuring device 182 measures the phase distribution of the wavefront of the light (i.e., the processing beam EL) that is incident on the map wavefront measuring device 182. The phase distribution of the wavefront measured by the map wavefront measuring device 182 and the correction wavefront measuring device 153 may be referred to as wavefront aberration or wavefront aberration distribution. The measurement result of the phase distribution of the wavefront by the map wavefront measuring device 182, i.e., the measurement result of the wavefront aberration, is output to the control unit 2.

The control unit 2 acquires the measurement results of the wavefront aberration by the wavefront measuring device for map 182. Based on the measurement results of the wavefront aberration by the wavefront measuring device for map 182, the control unit 2 can generate an aberration map showing the relationship between the irradiation positions of the processing beam EL (i.e., the multiple processing beams EL1 to EL9) and the wavefront aberration at the irradiation positions. Based on the generated aberration map, the control unit 2 can also generate a deformation map showing the relationship between the irradiation positions of the multiple processing beams EL1 to EL9 and the shape (deformation amount) of each part of the variable reflecting surface 118 of the deformable mirror 117 required to correct the wavefronts of the multiple processing beams EL1 to EL9 irradiated at the irradiation positions. The aberration map and deformation map generated in the control unit 2 are stored in a memory unit 90 provided in the control unit 2.

In the aberration map and deformation map, the irradiation positions (within a plane along the XY plane) of the multiple processing beams EL1 to EL9 in the processing shot area PSA are determined according to the deflection angles of the reflecting

surfaces

163X, 163Y of the X scanning mirror 162X and the Y scanning mirror 162Y in the galvanometer mirror 161. Therefore, the deflection angles of the reflecting

surfaces

163X, 163Y of the X scanning mirror 162X and the Y scanning mirror 162Y may be stored in the memory unit 90 in association with the irradiation positions of the multiple processing beams EL1 to EL9. The aberration map and deformation map stored in the memory unit 90 may also indicate the relationship between the deflection angles of the reflecting

surfaces

163X, 163Y of the X scanning mirror 162X and the Y scanning mirror 162Y and the wavefront aberration at the deflection angles. Furthermore, the irradiation positions (focus positions) of the multiple processing beams EL1 to EL9 in the Z-axis direction are determined according to the radius of curvature of the variable reflecting surface 118 of the deformable mirror 117. Therefore, the storage unit 90 may store the radius of curvature of the variable reflecting surface 118 of the deformable mirror 117 in association with the irradiation positions of the multiple processing beams EL1 to EL9 in the Z-axis direction.

In addition, in cases where the irradiation position (focus position) in the Z-axis direction changes depending on the irradiation positions of the multiple processing beams EL1 to EL9 in a plane along the XY plane, the storage unit 90 may store the radius of curvature of the variable reflecting surface 118 of the deformable mirror 117 in association with at least one of the irradiation positions of the multiple processing beams EL1 to EL9 in a plane along the XY plane and the deflection angles of the reflecting

surfaces

163X, 163Y of the X-scanning mirror 162X and the Y-scanning mirror 162Y.

Furthermore, in the aberration map, the wavefront aberration may be expressed in terms of the fourth, fifth, sixth, and ninth terms of the fringe Zernike polynomial when the wavefront aberration is expressed as the fringe Zernike polynomial. In other words, in the deformation map, the shape (amount of deformation) of each portion of the variable reflecting surface 118 of the deformable mirror 117 may be the shape (amount of deformation) of each portion of the variable reflecting surface 118 required to reduce the fourth, fifth, sixth, and ninth terms of the fringe Zernike polynomial.

The fourth term of the fringe Zernike polynomial is the fourth term when the terms of the Zernike polynomials are arranged in a manner called the fringe order. Similarly, the fifth, sixth, and ninth terms of the fringe Zernike polynomial are the fifth, sixth, and ninth terms when the terms of the Zernike polynomials are arranged in an order called the fringe order. The fourth term of the fringe Zernike polynomial is known to correspond to defocus. The fifth and sixth terms of the fringe Zernike polynomial are known to correspond to astigmatism. The ninth term of the fringe Zernike polynomial is known to correspond to spherical aberration. The deformable mirror 117 can correct defocus, astigmatism, and spherical aberration by deforming the variable reflecting surface 118 to reduce the fourth, fifth, sixth, and ninth terms of the fringe Zernike polynomials, which represent the wavefront aberration.

[Optical processing method]
Next, an optical processing method using the optical processing apparatus SYS configured as described above will be described with reference to the flowchart shown in FIG. 10. First, the map wavefront measuring device 182 of the map tool 180 measures the wavefront aberration to generate an aberration map (step ST1). At this time, the map tool 180 is temporarily attached to the stage 50 in a state where the workpiece W or the measurement object M is not placed on the stage 50. With the map tool 180 attached to the stage 50, the head drive system 40 moves the processing head 100 to align the optical axis of the map lens 181 with the optical axis of the objective optical system 170 (fθ lens 171). In addition, the diffractive optical element 111 is removed from the first optical path by the drive device of the processing optical system 110. The processing head 100 irradiates the processing beam EL toward the map tool 180 via the processing optical system 110, the synthesis optical system 150, the deflection optical system 160, and the objective optical system 170. At this time, the variable reflecting surface 118 of the deformable mirror 117 of the processing optical system 110 is deformed into a predetermined initial shape.

The map wavefront measuring device 182 measures the phase distribution of the wavefront of the light (i.e., the processing beam EL) incident on the map wavefront measuring device 182. The galvanometer mirror 161 of the deflection optical system 160 deflects the processing beam EL, so that the map wavefront measuring device 182 measures the phase distribution of the wavefront for multiple irradiation positions whose positions in the X-axis direction or the Y-axis direction in the processing shot area PSA differ by a predetermined interval. The deformable mirror 117 deforms the variable reflecting surface 118 to change the radius of curvature of the variable reflecting surface 118, so that the map wavefront measuring device 182 measures the phase distribution of the wavefront for multiple irradiation positions whose positions in the Z-axis direction differ by a predetermined interval. The predetermined interval between the multiple irradiation positions of the processing beam EL (multiple processing beams EL1 to EL9) is set to, for example, 1 mm. The irradiation positions of the processing beam EL (multiple processing beams EL1 to EL9) may be referred to as the measurement positions of the map wavefront measuring device 182. The measurement results of the wavefront phase distribution by the map wavefront measuring device 182, i.e., the measurement results of the wavefront aberration, are output to the control unit 2.

The control unit 2 acquires the measurement results of the wavefront aberration by the wavefront measuring device for map 182. Based on the measurement results of the wavefront aberration by the wavefront measuring device for map 182, the control unit 2 generates an aberration map that indicates the relationship between the irradiation positions of the multiple processing beams EL1 to EL9 and the wavefront aberration measured at multiple irradiation positions that differ in three-dimensional positions in the X-axis, Y-axis, and Z-axis directions. The aberration map generated in the control unit 2 is stored in the memory unit 90 of the control unit 2.

As described above, in the aberration map, the storage unit 90 may store the deflection angles of the reflecting

surfaces

163X and 163Y of the X-scanning mirror 162X and the Y-scanning mirror 162Y in the galvanometer mirror 161 and the radius of curvature of the variable reflecting surface 118 of the deformable mirror 117 in association with a plurality of irradiation positions that are different in the three-dimensional directions of the X-axis, Y-axis, and Z-axis directions. In the aberration map, the wavefront aberration may be expressed in terms of the fourth, fifth, sixth, and ninth terms of the fringe Zernike polynomial when the wavefront aberration is expressed as a fringe Zernike polynomial. In addition, in the aberration map, the wavefront aberration at positions between the plurality of irradiation positions spaced apart by the predetermined intervals described above may be found by fitting based on the wavefront aberration measured by the map wavefront measuring device 182.

Next, a deformation map of the deformable mirror 117 is generated (step ST2). At this time, based on the aberration map generated in the previous step (ST1), the control unit 2 generates a deformation map indicating the relationship between the irradiation position of the processing beam EL (i.e., the multiple processing beams EL1 to EL9) and the shape (amount of deformation) of each part of the variable reflecting surface 118 of the deformable mirror 117 required to correct the wavefront of the multiple processing beams EL1 to EL9 irradiated at that irradiation position. Note that the control unit 2 generates multiple deformation maps corresponding to multiple irradiation positions that differ in three-dimensional positions in the X-axis, Y-axis, and Z-axis directions. The (multiple) deformation maps generated in the control unit 2 are stored in the memory unit 90 of the control unit 2.

As described above, in the deformation map, the memory unit 90 may store the deflection angles of the reflecting

surfaces

163X, 163Y of the X-scanning mirror 162X and the Y-scanning mirror 162Y in the galvanometer mirror 161 and the radius of curvature of the variable reflecting surface 118 of the deformable mirror 117, linked to multiple irradiation positions that differ in three-dimensional positions in the X-axis direction, Y-axis direction, and Z-axis direction. In the deformation map, the shape (amount of deformation) of each part of the variable reflecting surface 118 of the deformable mirror 117 may be the shape (amount of deformation) of each part of the variable reflecting surface 118 required to reduce the fourth, fifth, sixth, and ninth terms of the fringe Zernike polynomial.

The step (ST1) of generating the aberration map and the step (ST2) of generating the deformation map are executed when the optical processing apparatus SYS is started up or during maintenance. After the step (ST1) of generating the aberration map and the step (ST2) of generating the deformation map are executed, the map tool 180 is removed from the stage 50. In addition, the diffractive optical element 111 is inserted into the first optical path by the drive device of the processing optical system 110.

Then, the formable mirror 117 is deformed when machining the workpiece W (step ST3). When machining the workpiece W, the workpiece W is placed on the mounting surface 51 of the stage 50. The machining head 100 irradiates multiple processing beams EL1 to EL9 onto the workpiece W via the machining optical system 110, the synthesis optical system 150, the deflection optical system 160, and the objective optical system 170. The galvanometer mirror 161 of the deflection optical system 160 deflects the multiple processing beams EL1 to EL9, thereby changing the irradiation positions of the multiple processing beams EL1 to EL9 irradiated onto the workpiece W via the objective optical system 170 along the direction perpendicular to the optical axis of the objective optical system 170 (the X-axis direction and the Y-axis direction). In addition, the deformable mirror 117 of the processing optical system 110 changes the irradiation position (focus position) in the Z-axis direction of the multiple processing beams EL1 to EL9 along the optical axis direction (Z-axis direction) of the objective optical system 170 by deforming the variable reflecting surface 118 to change the radius of curvature of the variable reflecting surface 118.

At this time, the control unit 2 transmits a control signal to the galvanometer mirror 161 of the deflection optical system 160 to control the deflection angles of the reflecting

surfaces

163X, 163Y (i.e., the beam deflection surfaces) of the X-scanning mirror 162X and the Y-scanning mirror 162Y in the galvanometer mirror 161. More specifically, the control unit 2 transmits a control signal including a command value for the deflection angle of the reflecting

surfaces

163X, 163Y of the X-scanning mirror 162X and the Y-scanning mirror 162Y to the galvanometer mirror 161.

At this time, the control unit 2 also refers to the deformation map stored in the storage unit 90. The control unit 2 transmits control signals based on the deformation map corresponding to the irradiation positions in the X-axis and Y-axis directions of the multiple processing beams EL1 to EL9 according to the command values of the deflection angles of the reflecting

surfaces

163X and 163Y of the X-scanning mirror 162X and the Y-scanning mirror 162Y and the irradiation positions (focusing positions) in the Z-axis direction of the multiple processing beams EL1 to EL9 to the deformable mirror 117 of the processing optical system 110. In this way, the control unit 2 controls the operation of the deformable mirror 117 based on the command value of the deflection angle. The deformable mirror 117 changes the wavefront in each beam cross section of the multiple processing beams EL1 to EL9 emitted from the variable reflecting surface 118 by deforming the variable reflecting surface 118 according to the control signal from the control unit 2.

The deformable mirror 117 also changes the irradiation positions (focus positions) in the Z-axis direction of the multiple processing beams EL1 to EL9 along the optical axis direction (Z-axis direction) of the objective optical system 170 by deforming the variable reflecting surface 118 in response to a control signal from the control unit 2 to change the radius of curvature of the variable reflecting surface 118. In this case, the deformable mirror 117 changes the irradiation positions (focus positions) in the Z-axis direction of the multiple processing beams EL1 to EL9, and also changes the wavefronts in the beam cross sections of the multiple processing beams EL1 to EL9 emitted from the variable reflecting surface 118.

As a result, by deforming the variable reflecting surface 118, the deformable mirror 117 can correct changes in the wavefront of each of the multiple processing beams EL1-EL9 from the objective optical system 170, which occurs as the irradiation positions of the multiple processing beams EL1-EL9 irradiated from the objective optical system 170 to the workpiece W move. Therefore, the deformable mirror 117 can correct the non-rotationally symmetric components of the wavefront of each of the multiple processing beams EL1-EL9 from the objective optical system 170 at their cross sections, and make the cross-sectional shapes of the multiple processing beams EL1-EL9 each circular. In this way, according to this embodiment, the cross-sectional shapes of the multiple processing beams EL1-EL9 can be kept constant and circular, regardless of the irradiation positions of the multiple processing beams EL1-EL9, thereby improving the machining accuracy of the workpiece W.

Note that at predetermined time intervals, the diffractive optical element 111 is temporarily removed from the first optical path by the driving device of the processing optical system 110, and the corrective wavefront measuring device 153 measures the phase distribution of the wavefront of the light (i.e., the processing beam EL) incident on the corrective wavefront measuring device 153. The measurement result of the wavefront phase distribution by the corrective wavefront measuring device 153, i.e., the measurement result of the wavefront aberration, is output to the control unit 2. The control unit 2 acquires the measurement result of the wavefront aberration by the corrective wavefront measuring device 153. The control unit 2 determines the amount of change in the wavefront aberration over time after the deformation map is generated based on the measurement result of the wavefront aberration by the corrective wavefront measuring device 153. Note that the amount of change in the wavefront aberration over time may be determined in the fourth, fifth, sixth, and ninth terms of the fringe Zernike polynomial. The control unit 2 transmits a control signal based on the (initial) deformation map plus a correction based on the amount of change in wavefront aberration over time to the deformable mirror 117 of the processing optical system 110.

As a result, the deformable mirror 117 is able to correct deformation of the variable reflecting surface 118 due to the heat emitted by the multiple processing beams EL1 to EL9, and changes in the wavefront of each beam cross section of the multiple processing beams EL1 to EL9 from the objective optical system 170 that occur due to fluctuations in the wavefront at the processing light source 10. Therefore, regardless of deformation of the variable reflecting surface 118 or fluctuations in the wavefront at the processing light source 10, the cross-sectional shapes of the multiple processing beams EL1 to EL9 can each be maintained at a constant circular shape, improving the processing accuracy of the workpiece W.

[Characteristic configuration of this embodiment]
In this embodiment, the optical device 101 used in the optical processing apparatus SYS includes a deformable mirror 117 that receives the multiple processing beams EL1 to EL9 from the processing light source 10 and changes the wavefront of each of the multiple processing beams EL1 to EL9 in a cross section, and a galvanometer mirror 161 that changes the traveling direction of the multiple processing beams EL1 to EL9 from the deformable mirror 117 and changes the irradiation position on the workpiece W of the multiple processing beams EL1 to EL9 irradiated onto the workpiece W via the objective optical system 170. Thereby, the deformable mirror 117, as a correction member, corrects the change in the wavefront of each of the multiple processing beams EL1 to EL9 in a cross section from the objective optical system 170 that occurs with the operation of the galvanometer mirror 161. In other words, the deformable mirror 117, as a correction member, corrects the change in the wavefront of each of the multiple processing beams EL1 to EL9 in a cross section from the objective optical system 170 that occurs with the movement of the irradiation position of the multiple processing beams EL1 to EL9 irradiated onto the workpiece W from the objective optical system 170. Therefore, as described above, regardless of the irradiation positions of the multiple processing beams EL1 to EL9, the cross-sectional shapes of the multiple processing beams EL1 to EL9 can each be maintained at a constant circular shape, thereby improving the processing accuracy of the workpiece W.

In this embodiment, the optical device 101 used in the optical processing device SYS includes a deformable mirror 117 on which the multiple processing beams EL1 to EL9 from the processing light source 10 are incident and which changes the wavefront of each of the multiple processing beams EL1 to EL9 in their cross sections, a relay optical system 125 on which the multiple processing beams EL1 to EL9 emitted from the deformable mirror 117 are incident, and a galvanometer mirror 161 which changes the traveling direction of the multiple processing beams EL1 to EL9 from the relay optical system 125 to make them incident on the objective optical system 170 and change the irradiation position of the multiple processing beams EL1 to EL9 on the workpiece W. The relay optical system 125 makes the variable reflection surface 118 of the deformable mirror 117 and the galvanometer mirror 161 conjugate with each other. As a result, as described above, regardless of the irradiation position of the multiple processing beams EL1 to EL9, the cross-sectional shape of each of the multiple processing beams EL1 to EL9 can be maintained in a constant circular shape, thereby improving the processing accuracy of the workpiece W. In addition, it is possible to place the variable reflecting surface 118 of the deformable mirror 117 at a pupil conjugate position, and the wavefronts of the multiple processing beams EL1 to EL9 that converge on the variable reflecting surface 118 can be efficiently changed.

In this embodiment, the optical device 101 used in the optical processing device SYS includes a diffractive optical element 111 that splits the processing beam EL from the processing light source 10 into multiple processing beams EL1 to EL9, a conjugate optical system 112 on which the multiple processing beams EL1 to EL9 emitted from the diffractive optical element 111 are incident and which forms a conjugate position CP that is optically conjugate with the grating surface 111a of the diffractive optical element 111, and a deformable mirror 117 on which the multiple processing beams EL1 to EL9 from the conjugate optical system 112 are incident and which changes the wavefront of each beam cross section of the multiple processing beams EL1 to EL9 that are emitted and then incident on the objective optical system 170. The variable reflecting surface 118 of the deformable mirror 117 is located at the conjugate position CP of the grating surface 111a. As a result, as described above, the cross-sectional shapes of the multiple processing beams EL1 to EL9 can be maintained at a constant circular shape, thereby improving the processing accuracy of the workpiece W. In addition, it is possible to place the variable reflecting surface 118 of the deformable mirror 117 at the pupil conjugate position (conjugate position CP), and the wavefronts of the multiple processing beams EL1 to EL9 that converge on the variable reflecting surface 118 can be efficiently changed.

In this embodiment, the optical device 101 used in the optical processing device SYS includes a polarized beam splitter 116 on which the multiple processing beams EL1 to EL9 from the processing light source 10 are incident, a deformable mirror 117 on which the multiple processing beams EL1 to EL9 are incident via the polarized beam splitter 116, which changes the wavefront of each beam cross section of the multiple processing beams EL1 to EL9 that are emitted and then incident on the polarized beam splitter 116, and a first quarter-wave plate 122 arranged in the optical path of the multiple processing beams EL1 to EL9 whose wavefronts have been changed. As a result, as described above, the cross-sectional shapes of the multiple processing beams EL1 to EL9 can be kept constant and the processing accuracy of the workpiece W can be improved. In addition, by changing the polarization state of the multiple processing beams EL1 to EL9 using the first quarter-wave plate 122, the multiple processing beams EL1 to EL9 that are incident on the deformable mirror 117 via the polarized beam splitter 116 can be emitted toward the workpiece W without returning to the processing light source 10.

In this embodiment, the optical device 101 used in the optical processing device SYS is also configured to include a deformable mirror 117 that receives the multiple processing beams EL1 to EL9 from the processing light source 10 and changes the wavefront of each of the multiple processing beams EL1 to EL9 in their cross sections. The deformable mirror 117 changes the wavefronts of the multiple processing beams EL1 to EL9 emitted from the deformable mirror 117, and corrects the non-rotationally symmetric components of the wavefronts of the multiple processing beams EL1 to EL9 from the objective optical system 170 when changing the focusing positions of the multiple processing beams EL1 to EL9 from the objective optical system 170 in the optical axis direction of the objective optical system 170. As a result, as described above, the irradiation positions of the multiple processing beams EL1 to EL9 in the Z axis direction (the focusing positions in the optical axis direction of the objective optical system 170) can be changed at high speed, and the cross-sectional shapes of the multiple processing beams EL1 to EL9 can be maintained as circular when changing the irradiation positions of the multiple processing beams EL1 to EL9 in the Z axis direction.

[Modification]
In the above embodiment, the entrance pupil PU of the objective optical system 170 is located between the X-scanning mirror 162X and the Y-scanning mirror 162Y in the galvanometer mirror 161, but is not limited thereto. For example, the X-scanning mirror 162X may be arranged at the position of the entrance pupil PU of the objective optical system 170, and the Y-scanning mirror 162Y may be arranged at the position of the entrance pupil PU of the objective optical system 170. Furthermore, the galvanometer mirror 161 may include a third scanning mirror in addition to the X-scanning mirror 162X and the Y-scanning mirror 162Y, and may include two or more scanning mirrors (deflection mirrors). In this case, the entrance pupil PU of the objective optical system 170 may be located anywhere between the two or more scanning mirrors. Furthermore, one of the two or more scanning mirrors may be arranged at the position of the entrance pupil PU of the objective optical system 170. Furthermore, a relay optical system that makes the reflecting surface 163X of the X scanning mirror 162X and the reflecting surface 163Y of the Y scanning mirror 162Y optically conjugate with each other may be disposed between the X scanning mirror 162X and the Y scanning mirror 162Y. In this case, the reflecting surface 163X of the X scanning mirror 162X and the reflecting surface 163Y of the Y scanning mirror 162Y may be located at the entrance pupil PU of the objective optical system 170 or at a position conjugate with the entrance pupil PU.

When the galvanometer mirror 161 as a deflection member has a plurality of reflecting

surfaces

163X, 163Y that can rotate around a first axis and a second axis that intersect with each other (or around a first axis and a second axis that are in a twisted relationship with each other), the plurality of processing beams EL are incident on the second or subsequent reflecting surface (reflecting surface 163Y in the example of FIG. 3) in a state in which the direction of the irradiation positions of the plurality of processing beams EL on the workpiece W deviates from the direction perpendicular to the rotation axis of the reflecting surface. Therefore, depending on the rotation of the reflecting surface 163Y, the arrangement direction of the irradiation positions of the plurality of processing beams EL on the workpiece W may rotate around the optical axis of the objective optical system 170 or an axis parallel to the optical axis. If the rotation of the arrangement direction of the irradiation positions exceeds the allowable range, the diffractive optical element 111 as a beam splitting member may be rotated around the optical axis according to the deflection angle of the reflecting

surfaces

163X, 163Y of the X-scanning mirror 162X and the Y-scanning mirror 162Y. In other words, the direction in which the multiple processing beams EL are emitted from the diffractive optical element 111 as a beam splitting member may be changed according to the deflection angles of the reflecting

surfaces

163X and 163Y of the X-scanning mirror 162X and the Y-scanning mirror 162Y. In this case, a rotary drive device for rotating the diffractive optical element 111 may be provided. The rotary drive amount of this rotary drive device may be controlled by the control unit 2 or the above-mentioned first control device or second control device. The storage unit of the control unit 2 or the first control device or the second control device may store the relationship between the command value of the deflection angle sent to the deflection member and the command value of the rotation drive amount of the diffractive optical element 111, and the control unit 2 or the first control device or the second control device may control the deflection member and the rotary drive device using the command value of the deflection angle and the command value of the rotation drive amount.

Furthermore, the galvanometer mirror as the deflection member may be a two-axis galvanometer mirror with reflective surfaces that can rotate around two mutually intersecting (orthogonal) axes, thereby reducing the rotation in the arrangement direction of the above-mentioned irradiation positions. The galvanometer mirror as the deflection member may be configured using multiple one-axis scanning mirrors whose reflective surfaces are positioned conjugate to each other by a relay optical system, thereby reducing the rotation in the arrangement direction of the above-mentioned irradiation positions.

In the above embodiment, the control unit 2 controls the operation of the deformable mirror 117 based on the command value of the deflection angle of the reflecting

surfaces

163X, 163Y of the X-scanning mirror 162X and the Y-scanning mirror 162Y in the galvanometer mirror 161, but this is not limited to the above. For example, the control unit 2 may control the operation of the deformable mirror 117 based on information on the deflection angle of the reflecting

surfaces

163X, 163Y of the X-scanning mirror 162X and the Y-scanning mirror 162Y output from a rotary encoder provided on the X-scanning mirror 162X and the Y-scanning mirror 162Y. Specifically, the control unit 2 may transmit to the deformable mirror 117 a control signal based on a deformation map corresponding to the irradiation positions in the X-axis direction and the Y-axis direction of the multiple processing beams EL1 to EL9 according to the deflection angles output from the rotary encoders of the X-scanning mirror 162X and the Y-scanning mirror 162Y and the irradiation positions (focusing positions) in the Z-axis direction of the multiple processing beams EL1 to EL9.

In the above embodiment, the control unit 2 determines the amount of change in wavefront aberration over time after the deformation map is generated based on the measurement result of the wavefront aberration by the corrective wavefront measuring device 153, and corrects the control signal to be output to the deformable mirror 117, but this is not limited to the above. For example, the control unit 2 may correct the control signal to be output to the deformable mirror 117 based on a first measurement result of the wavefront aberration by the corrective wavefront measuring device 153 and a second measurement result of the wavefront aberration measured by the corrective wavefront measuring device 153 before obtaining the first measurement result.

In the above embodiment, the map wavefront measuring device 182 and the correction wavefront measuring device 153 are configured using a Shack-Hartmann sensor, but this is not limited to this. For example, the map wavefront measuring device 182 and the correction wavefront measuring device 153 may be configured using a wavefront sensor that uses a shearing interference method.

In the above embodiment, the map wavefront measuring device 182 and the corrective wavefront measuring device 153, which are configured using a Shack-Hartmann sensor, measure the wavefront aberration with the diffractive optical element 111 removed from the first optical path, but this is not limited to the above. For example, when measuring the wavefront aberration with the diffractive optical element 111 remaining inserted in the first optical path, the map wavefront measuring device 182 (corrective wavefront measuring device 153) may measure the wavefront aberration for each of the multiple processing beams EL1 to EL9 by providing blinds that can individually block the multiple processing beams EL1 to EL9 at positions where the multiple processing beams EL1 to EL9 are spatially separated. The position where the multiple processing beams EL1 to EL9 are spatially separated is typically a surface that optically undergoes a Fourier transform with respect to the grating surface 111a of the diffractive optical element 111 or the variable reflecting surface 118 of the deformable mirror 117, such as the pupil plane of the conjugate optical system 112 or the pupil plane of the relay optical system 125.

In addition, when measuring wavefront aberration with the diffractive optical element 111 still inserted in the first optical path, if the distance between the spots of the multiple processing beams EL1 to EL9 on the detector in the map wavefront measuring device 182 (corrective wavefront measuring device 153) is small, the measurement results for each spot of the multiple processing beams EL1 to EL9 may be averaged. In addition, when measuring wavefront aberration with the diffractive optical element 111 still inserted in the first optical path, the multiple processing beams EL1 to EL9 may be separated by attaching a field-angle limiting member such as a lens hood that limits the field angle of the incident light beam to the incident side of the lens array (or DOE array) in the map wavefront measuring device 182 (corrective wavefront measuring device 153).

In the above embodiment, when generating the aberration map, the map tool 180 does not have to be temporarily attached to the stage 50. For example, a tool drive system for moving the map tool 180 may be provided. In this case, when generating the aberration map, the tool drive system may move the map tool 180 to a predetermined aberration measurement position between the processing head 100 and the stage 50. Note that the predetermined aberration measurement position is a position where the wavefront aberration can be measured by the map wavefront measurement device 182 of the map tool 180. Also, the map tool 180 may be permanently installed on the stage 50 of the optical processing device SYS. Note that the optical processing device SYS does not have to be equipped with the map tool 180. In this case, the aberration map may be acquired using the map tool 180 at the manufacturing plant of the processing head 100 when the processing head 100 is manufactured.

In the above embodiment, the map tool 180 is temporarily attached to the stage 50, and the wavefront aberration is measured by the map wavefront measuring device 182 of the map tool 180, but this is not limited to the above. For example, a light receiving device 190 (see FIG. 11) disclosed in International Publication No. 2021/210104 etc. may be provided on the stage 50 to measure the cross-sectional shapes of the multiple processing beams EL1 to EL9 focused and irradiated onto a surface corresponding to a surface on the workpiece W. In this case, the control unit 2 may generate a cross-sectional shape map showing the relationship between the irradiation positions of the multiple processing beams EL1 to EL9 and the cross-sectional shapes of the multiple processing beams EL1 to EL9 measured at the irradiation positions based on the measurement results by the light receiving device 190. In addition, the control unit 2 may generate a deformation map that indicates the relationship between the irradiation positions of the multiple processing beams EL1 to EL9 and the shapes (deformation amounts) of each portion of the variable reflecting surface 118 of the deformable mirror 117 that are required to correct the cross-sectional shapes of the multiple processing beams EL1 to EL9 irradiated to the irradiation positions, based on the generated cross-sectional shape map.

The light receiving device 190 may be provided on the outer periphery 52 of the stage 50, which is off the mounting surface 51, as shown in FIG. 11, for example. The light receiving device 190 includes a beam passing member 191 and a light receiving element 195. The beam passing member 191 is provided above the light receiving element 195. The beam passing member 191 includes a glass substrate 192 and an attenuation film 193 formed on at least a part of the surface of the glass substrate 192. The attenuation film 193 attenuates the light beam (processing beam) incident on the attenuation film 193, and prevents it from being incident on the light receiving element 195. The attenuation film 193 has an opening 194 formed therein through which at least one of the multiple processing beams EL1 to EL9 irradiated from the processing head 100 can pass. The light receiving element 195 detects at least one of the multiple processing beams EL1 to EL9 that have passed through the opening 194 of the beam passing member 191 (attenuation film 193).

Also, for example, the above-mentioned light receiving device 190 may be provided on the stage 50 to measure the cross-sectional intensity distribution of the multiple processing beams EL1 to EL9 focused and irradiated on a surface corresponding to the surface on the workpiece W, and the cross-sectional intensity distribution of the multiple processing beams EL1 to EL9 at a defocused surface away from the surface corresponding to the surface on the workpiece W in the optical axis direction (Z-axis direction). In this case, the control unit 2 may use the phase retrieval method disclosed in JP-A-10-284368 etc. to obtain the wavefront aberration from the cross-sectional intensity distribution of the multiple processing beams EL1 to EL9 at the surface corresponding to the surface on the workpiece W measured by the light receiving device 190 and the cross-sectional intensity distribution of the multiple processing beams EL1 to EL9 at the defocused surface. The control unit 2 can generate the above-mentioned aberration map based on the wavefront aberration obtained using the phase retrieval method.

The light receiving device 190 may be provided separately from the stage 50. In this case, for example, a device drive system for moving the light receiving device 190 may be provided. When generating a cross-sectional shape map or an aberration map, the device drive system may move the light receiving device 190 to a predetermined cross-sectional measurement position or a predetermined defocus position between the processing head 100 and the stage 50. The predetermined cross-sectional measurement position is a position where the light receiving device 190 can measure the cross-sectional shape or cross-sectional intensity distribution of the multiple processing beams EL1 to EL9 on a plane corresponding to a surface on the workpiece W. The predetermined defocus position is a position where the light receiving device 190 can measure the cross-sectional intensity distribution of the multiple processing beams EL1 to EL9 on the defocus plane.

In the above embodiment, a deformable mirror 117 is used as the wavefront modification member, but this is not limited to this. For example, a reflective liquid crystal element such as a Liquid Crystal on Silicon-Spatial Light Modulator (LCOS-SLM) or a transmissive liquid crystal element may be used as the wavefront modification member. Also, a mirror array consisting of multiple movable mirror elements arranged in an array may be used as the wavefront modification member.

The deformable mirror may be cooled to reduce the thermal effects caused by heat generation from the deformable mirror. For example, the deformable mirror 117 as a wavefront changing member may be housed in a housing with an optical window, and a fluid such as gas may be circulated within the housing to cool the deformable mirror 117. In this case, the optical window of the housing may be located close to the light entrance side (light exit side) of the variable reflecting surface 118 of the deformable mirror 117. A heat sink may also be provided on the back surface of the deformable mirror 117.

The following additional notes are provided regarding the above-described embodiment.
[Appendix 1]
An optical scanning device used in an optical device that irradiates a light beam from a light source onto a workpiece through an objective optical system,
a wavefront modifying member onto which the light beam from the light source is incident and which modifies a wavefront of the light beam in a beam cross section;
an optical scanning device comprising: a deflecting member that changes the traveling direction of the light beam from the wavefront changing member, causes the light beam to enter the objective optical system, and changes the irradiation position of the light beam on the workpiece;
[Appendix 2]
An optical scanning device used in an optical device that irradiates a light beam from a light source onto a workpiece through an objective optical system,
a wavefront modifying member onto which the light beam from the light source is incident and which modifies a wavefront of the light beam in a beam cross section;
a relay optical system into which the light beam emitted from the wavefront modifying member is incident;
a deflection member that changes a traveling direction of the light beam from the relay optical system to make the light beam incident on the objective optical system and changes an irradiation position of the light beam on the workpiece,
The relay optical system is an optical scanning device in which the wavefront changing surface of the wavefront changing member and the deflecting member are conjugated to each other.
[Appendix 3]
An optical device that irradiates a light beam from a light source onto a workpiece through an objective optical system,
a beam splitter that splits the light beam from the light source into a plurality of light beams;
a conjugate optical system onto which the plurality of light beams emitted from the beam splitting member are incident and which forms a conjugate position optically conjugate with a beam splitting surface of the beam splitting member;
a wavefront changing member into which the plurality of light beams from the conjugate optical system are incident and which changes a wavefront of the plurality of light beams in a beam cross section to be emitted, and causes the plurality of light beams to be incident into the objective optical system;
An optical device in which the wavefront modifying surface of the wavefront modifying member is located at the conjugate position of the beam splitting surface.
[Appendix 4]
An optical device that irradiates a light beam from a light source onto a workpiece through an objective optical system,
a polarizing beam splitter on which the light beam from the light source is incident;
a wavefront changing member that changes a wavefront of the light beam in a beam cross section that is incident on the light beam passing through the polarizing beam splitter and that emits the light beam and causes the light beam to be incident on the polarizing beam splitter;
and a quarter wave plate disposed in the path of the wavefront-modified light beam.
[Appendix 5]
An optical device that irradiates a light beam from a light source onto a workpiece through an objective optical system,
a wavefront modifying member onto which the light beam from the light source is incident and which modifies a wavefront of the light beam in a beam cross section,
The wavefront changing member is an optical device that changes the non-rotationally symmetric component of the wavefront of the light beam from the objective optical system when changing the focusing position of the light beam from the objective optical system relative to the optical axis direction of the objective optical system by changing the wavefront of the light beam emitted from the wavefront changing member.
[Appendix 6]
An optical processing method for processing a workpiece by irradiating a processing beam from a light source onto the workpiece through an objective optical system, comprising:
modifying a wavefront of the processing beam from the light source in a beam cross section;
and changing a direction of travel of the processing beam whose wavefront has been changed, thereby changing an irradiation position on the workpiece of the processing beam irradiated onto the workpiece via the objective optical system.
[Appendix 7]
The optical processing method according to claim 6, wherein the state of the wavefront change is changed when the irradiation position is changed.
[Appendix 8]
An optical device used in an optical processing device that processes a workpiece by irradiating a processing beam from a light source onto the workpiece through an objective optical system,
a beam splitting member that splits the processing beam from the light source into a plurality of processing beams;
a rotary drive device that rotates the beam splitting member;
a deflection member that changes a traveling direction of the processing beam from the beam splitting member and changes an irradiation position on the workpiece of the processing beam that is irradiated onto the workpiece via the objective optical system;
a control unit that controls the rotation of the beam splitting member by the rotary drive device based on the operation of the deflection member.
[Appendix 9]
9. The optical device according to claim 8, wherein the control unit controls a deflection angle of the beam deflection surface of the deflection member.
[Appendix 10]
10. The optical device of claim 9, wherein the control unit controls the rotation of the beam splitting member by the rotary drive device based on information about the deflection angle from the deflection member.
[Appendix 11]
10. The optical device according to claim 9, wherein the control unit sends a command value of the deflection angle to the deflection member and controls the rotation of the beam splitting member by the rotary drive device based on the command value.
[Appendix 12]
12. The optical device according to claim 9, wherein the control unit includes a memory unit that stores the relationship between the deflection angle and the amount of rotation of the beam splitting member by the rotary drive device.
[Appendix 13]
13. The optical device according to any one of claims 8 to 12, wherein the deflection member comprises two or more deflection mirrors having reflective surfaces rotatable around a rotation axis.
[Appendix 14]
14. The optical device of claim 13, wherein at least one of the two or more deflection mirrors is positioned at a position away from an entrance pupil of the objective optical system.

At least some of the constituent elements of the present embodiment described above can be appropriately combined with at least some of the other constituent elements of the present embodiment described above. Some of the constituent elements of the present embodiment described above may not be used.

The present invention is not limited to the above-described embodiment, but may be modified as appropriate within the scope of the claims and the entire specification without violating the spirit or concept of the invention, and optical devices, optical processing devices, optical processing methods, and correction members that involve such modifications are also included within the technical scope of the present invention.

SYS Optical processing device 1 Processing unit 2 Control unit 90 Memory unit 100 Processing head 101 Optical device 110 Processing optical system 111 Diffractive optical element (111a grating surface)
112 Conjugate optical system 115 Wavefront changing unit 116 Polarizing beam splitter 117 Deformable mirror 118 Variable reflecting surface 119 Beam dumper 121 First 1/2 wave plate 122 First 1/4 wave plate 123 Second 1/2 wave plate 124 Second 1/4 wave plate 125 Relay optical system 150 Synthesis optical system 153 Corrective wavefront measuring device 160 Deflection optical system 161 Galvanometer mirror 162X X-scanning mirror 162Y Y-scanning mirror 170 Objective optical system 171 fθ lens

Claims

An optical device used in an optical processing device that processes a workpiece by irradiating a processing beam from a light source onto the workpiece through an objective optical system,
a wavefront modifying member onto which the processing beam from the light source is incident and which modifies a wavefront of the processing beam in a beam cross section;
an optical device comprising: a deflection member that changes the direction of travel of the processing beam from the wavefront changing member and changes the irradiation position on the workpiece of the processing beam that is irradiated onto the workpiece via the objective optical system.
The optical device of claim 1 further comprising a control unit that controls the change in the wavefront caused by the wavefront changing member based on the operation of the deflection member.
The optical device according to claim 2, wherein the control unit controls the deflection angle of the beam deflection surface of the deflection member.
The optical device according to claim 3, wherein the control unit controls the change in the wavefront by the wavefront changing member based on information about the deflection angle from the deflection member.
The optical device according to claim 3, wherein the control unit sends a command value of the deflection angle to the deflection member and controls the change in the wavefront by the wavefront changing member based on the command value.
The optical device according to any one of claims 3 to 5, wherein the control unit includes a memory unit that stores the relationship between the deflection angle and the phase distribution of the wavefront of the processing beam that is changed by the wavefront changing member.
The optical device according to claim 6, which determines the relationship between the deflection angle and the phase distribution of the wavefront of the processing beam modified by the wavefront modifying member based on the measurement result of the processing beam through the objective optical system.
The optical device according to claim 7, in which the relationship is determined based on the measurement results of the processing beam at multiple measurement positions on the workpiece side of the objective optical system.
The optical device of claim 8, wherein the plurality of measurement positions include a plurality of positions on a plane intersecting the optical axis of the objective optical system.
The optical device according to claim 8 or 9, wherein the plurality of measurement positions include a plurality of positions along the optical axis direction of the objective optical system.
The optical device according to any one of claims 6 to 10, wherein the wavefront modification member modifies the fourth, fifth, sixth, and ninth terms of the fringe Zernike polynomial when the phase distribution of the wavefront is expressed as a fringe Zernike polynomial.
The optical device according to any one of claims 1 to 11, further comprising a wavefront measuring device that measures the phase distribution of the wavefront in the cross section of the processing beam from the wavefront changing member.
a control unit that controls the change of the wavefront by the wavefront changing member based on the operation of the deflection member,
The optical device according to claim 12 , wherein the control unit controls the modification of the wavefront by the wavefront modifying member based on a measurement result by the wavefront measuring device.
a control unit that controls the change of the wavefront by the wavefront changing member based on the operation of the deflection member,
13. The optical device according to claim 12, wherein the control unit controls the modification of the wavefront by the wavefront modifying member based on a first measurement result by the wavefront measuring device and a second measurement result measured by the wavefront measuring device before obtaining the first measurement result.
The optical device according to any one of claims 1 to 14, wherein the wavefront changing member has a deformable variable reflecting surface on which the processing beam from the light source is incident, and the wavefront of the processing beam reflected by the variable reflecting surface is changed by deformation of the variable reflecting surface.
The optical device according to any one of claims 1 to 15, further comprising a relay optical system that optically conjugates the wavefront changing surface of the wavefront changing member with the deflection member.
The optical device according to claim 16, wherein the deflection member is disposed at the entrance pupil of the objective optical system.
The optical device according to claim 17, wherein the relay optical system optically conjugates the wavefront changing surface of the wavefront changing member with the entrance pupil of the objective optical system.
The optical device according to any one of claims 16 to 18, wherein the deflection member comprises two or more deflection mirrors having reflective surfaces that can rotate around a rotation axis.
The optical device according to claim 19, wherein the entrance pupil of the objective optical system is located between the two or more deflection mirrors.
The optical device according to claim 19, wherein one of the two or more deflection mirrors is located at the entrance pupil of the objective optical system.
The optical device according to any one of claims 1 to 21, further comprising a beam splitting member that splits the processing beam from the light source into a plurality of processing beams.
a conjugate optical system on which the plurality of processing beams emitted from the beam splitting member are incident and which forms a conjugate position optically conjugate with a beam splitting surface of the beam splitting member,
23. The optical device of claim 22, wherein the wavefront modifying surface of the wavefront modifying member is located at the conjugate position of the beam splitting surface.
a polarizing beam splitter on which the processing beam from the light source is incident;
Further comprising a quarter-wave plate disposed in an optical path between the polarizing beam splitter and the workpiece;
An optical device described in any one of claims 1 to 23, wherein the wavefront changing member changes the wavefront of the processing beam in the beam cross section that is incident on and emerges from the processing beam via the polarizing beam splitter, and causes the processing beam to be incident on the polarizing beam splitter.
the polarizing beam splitter splits light incident along a first optical path into light traveling along a second optical path and a third optical path;
the wavefront modifying member is disposed in the second optical path and returns the processing beam incident thereon to the polarizing beam splitter;
25. The optical device of claim 24, wherein the processing beam exits the wavefront modifying member via the polarizing beam splitter along a fourth optical path.
The optical device of claim 25, further comprising a half-wave plate disposed in the fourth optical path.
The optical device according to claim 25 or 26, further comprising a beam damper disposed in the third optical path.
The optical device according to any one of claims 24 to 27, wherein the processing beam is linearly polarized and incident on the polarizing beam splitter.
The optical device according to any one of claims 24 to 28, further comprising a polarization direction adjustment member disposed in the optical path from the light source to the polarizing beam splitter, for adjusting the polarization direction of the processing beam incident on the polarizing beam splitter.
The optical device according to any one of claims 24 to 29, further comprising a quarter-wave plate disposed between the polarizing beam splitter and the wavefront modifying member.
The optical device according to any one of claims 1 to 30, wherein the wavefront modification member modifies the wavefront of the processing beam emitted from the wavefront modification member to correct a non-rotationally symmetric component of the wavefront of the processing beam from the objective optical system when changing the focusing position of the processing beam from the objective optical system in the optical axis direction of the objective optical system.
An optical device used in an optical processing device that processes a workpiece by irradiating a processing beam from a light source onto the workpiece through an objective optical system,
a wavefront modifying member onto which the processing beam from the light source is incident and which modifies a wavefront of the processing beam in a beam cross section;
a relay optical system into which the processing beam emitted from the wavefront modifying member is incident;
a deflection member that changes a traveling direction of the processing beam from the relay optical system to make the processing beam incident on the objective optical system and changes an irradiation position of the processing beam on the workpiece,
The relay optical system is an optical device that makes the wavefront changing surface of the wavefront changing member optically conjugate with the deflection member.
The optical device according to claim 32, wherein the deflection member is disposed at the entrance pupil of the objective optical system.
The optical device according to claim 33, wherein the relay optical system optically conjugates the wavefront changing surface of the wavefront changing member and the entrance pupil of the objective optical system with each other.
The optical device according to any one of claims 32 to 34, wherein the deflection member comprises two or more deflection mirrors having reflective surfaces that can rotate around a rotation axis.
The optical device of claim 35, wherein the entrance pupil of the objective optical system is located between the two or more deflection mirrors.
The optical device according to claim 35, wherein one of the two or more deflection mirrors is located at the entrance pupil of the objective optical system.
An optical device used in an optical processing device that processes a workpiece by irradiating a processing beam from a light source onto the workpiece through an objective optical system,
a beam splitting member that splits the processing beam from the light source into a plurality of processing beams;
a conjugate optical system onto which the plurality of processing beams emitted from the beam splitting member are incident and which forms a conjugate position optically conjugate with a beam splitting surface of the beam splitting member;
a wavefront changing member on which the plurality of processing beams from the conjugate optical system are incident and which changes a wavefront of the plurality of processing beams in a beam cross section to be emitted and causes the plurality of processing beams to be incident on the objective optical system;
An optical device in which the wavefront modifying surface of the wavefront modifying member is located at the conjugate position of the beam splitting surface.
An optical device used in an optical processing device that processes a workpiece by irradiating a processing beam from a light source onto the workpiece through an objective optical system,
a polarizing beam splitter on which the processing beam from the light source is incident;
a wavefront changing member that changes a wavefront of the processing beam in a beam cross section that is incident on the processing beam via the polarizing beam splitter and that outputs the processing beam and causes the processing beam to be incident on the polarizing beam splitter;
a quarter wave plate disposed in the optical path of the wavefront-modified processing beam.
An optical device used in an optical processing device that processes a workpiece by irradiating a processing beam from a light source onto the workpiece through an objective optical system,
a wavefront modifying member onto which the processing beam from the light source is incident and which modifies a wavefront of the processing beam in a beam cross section,
The wavefront changing member is an optical device that corrects non-rotationally symmetric components of the wavefront of the processing beam from the objective optical system when changing the focusing position of the processing beam from the objective optical system relative to the optical axis direction of the objective optical system by changing the wavefront of the processing beam emitted from the wavefront changing member.
The optical device according to any one of claims 1 to 40, wherein the wavefront modification member modifies the phase distribution of the wavefront of the processing beam emitted from the wavefront modification member.
An optical processing apparatus that processes a workpiece by irradiating a processing beam from a light source onto the workpiece through an objective optical system,
An optical processing apparatus comprising the optical device according to any one of claims 1 to 41.
An optical processing method for processing a workpiece by irradiating a processing beam from a light source through an objective optical system onto the workpiece, comprising:
The processing beam from the light source is made to be incident on the optical device according to any one of claims 1 to 41,
An optical processing method in which the processing beam from the optical device is irradiated onto the workpiece via the objective optical system.
A correction member used in an optical device that scanably irradiates a workpiece with a light beam from a light source via a deflection member and an objective optical system, comprising:
a wavefront modifying member disposed in an optical path between the light source and the deflecting member, the wavefront modifying member modifying a wavefront of the light beam in a cross section directed toward the deflecting member;
The wavefront modifying member is a correction member that corrects a change in the wavefront in the beam cross section of the light beam from the objective optical system, which change occurs due to the operation of the deflecting member.
A correction member used in an optical device that scanably irradiates a workpiece with a light beam from a light source via a deflection member and an objective optical system, comprising:
a wavefront modifying member disposed in an optical path between the light source and the deflecting member, the wavefront modifying member modifying a wavefront of the light beam in a cross section directed toward the deflecting member;
The wavefront changing member is a correction member that corrects changes in the wavefront in the beam cross section of the light beam from the objective optical system that occur as the irradiation position of the light beam irradiated from the objective optical system to the workpiece moves.