Optical processing device and optical processing method

Abstract

An optical processing device (1) comprises: a condensing optical system (16) that irradiates an object (18) with processing light (R1) having a first wavelength as a peak wavelength and measurement light (R2) having a second wavelength different from the first wavelength as a peak wavelength; a processing optical system (11) that causes the processing light from a processing light source (10) to enter the condensing optical system; and a measurement device (23) which causes the measurement light to enter the condensing optical system and on which detection light generated as a result of the irradiation of the object with the measurement light is incident via the condensing optical system. The condensing optical system comprises a diffractive optical element (DOE) which transmits the processing light and the measurement light directed toward the object and on which detection light from the object is incident. The diffractive optical element diffracts the processing light to generate m-th order diffracted light, and diffracts the measuring light to generate n-th order diffracted light. Let λ1 be the first wavelength of the processing light and let λ2 be the second wavelength of the measurement light, in which case the conditional expression 0.96(m / n) < λ2 / λ1 < 1.04(m / n) is satisfied.

Description

Optical processing device and optical processing method

[0001] The present invention relates to an optical processing apparatus and an optical processing method capable of processing an object with processing light.

[0002] As a processing device capable of processing a target object, Patent Document 1 describes an optical processing device that forms a structure by irradiating a surface of an object with processing light. This type of optical processing device is required to process the target object appropriately.

[0003] U.S. Application No. 8,735,768

[0004] According to a first aspect, an optical processing apparatus includes a focusing optical system that irradiates an object with processing light having a first wavelength as a peak wavelength and measurement light having a second wavelength different from the first wavelength, a processing optical system that causes the processing light from a processing light source to be incident on the focusing optical system, and a measurement device that causes the measurement light to be incident on the focusing optical system and into which detection light generated by the measurement light irradiated on the object is incident via the focusing optical system, the focusing optical system including a diffractive optical element that passes the processing light and the measurement light directed toward the object and onto which the detection light from the object is incident, the diffractive optical element diffracts the processing light to generate m-th order diffracted light and diffracts the measurement light to generate n-th order diffracted light, and satisfies the conditional expression 0.96(m / n)<λ2 / λ1<1.04(m / n), where m and n are integers excluding 0.

[0005] According to a second aspect, an optical processing apparatus includes a focusing optical system that irradiates an object with processing light having a first wavelength as a peak wavelength and measurement light having a second wavelength different from the first wavelength; a processing optical system that causes the processing light from a processing light source to enter the focusing optical system; a measurement device that causes the measurement light to enter the focusing optical system and into which detection light generated by the measurement light irradiated to the object enters via the focusing optical system; and a scanning optical element that deflects and scans the processing light from the processing optical system and the measurement light from the measurement device to cause them to enter the focusing optical system, wherein the focusing optical system includes a diffractive optical element that passes the processing light and the measurement light directed toward the object and into which the detection light from the object enters, and the irradiation range of the processing light irradiated to the diffractive optical element moves on the surface of the diffractive optical element in accordance with the deflection scanning by the scanning optical element, and the focusing optical system includes an optical filter element that changes the amount of light passing depending on the position where the light passes.

[0006] According to a third aspect, the optical processing device includes a focusing optical system that irradiates an object with processing light having a first wavelength as a peak wavelength and measurement light having a second wavelength different from the first wavelength; a processing optical system that causes the processing light from a processing light source to be incident on the focusing optical system; a measurement device that causes the measurement light to be incident on the focusing optical system and into which detection light generated by the measurement light irradiated on the object is incident via the focusing optical system; a scanning optical member that deflects and scans the processing light from the processing optical system and the measurement light from the measurement device to be incident on the focusing optical system; and a processing light intensity control device that controls at least one of the processing light source and the processing optical system to actively change the light intensity of the processing light directed toward the focusing optical system, wherein the focusing optical system allows the processing light and the measurement light directed toward the object to pass through and includes a diffractive optical element onto which the detection light from the object is incident, the irradiation range of the processing light irradiated to the diffractive optical element moves on the surface of the diffractive optical element in accordance with the deflection scanning by the scanning optical element, and the processing light intensity control device changes the light intensity of the processing light in accordance with the deflection scanning by the scanning optical element.

[0007] According to a fourth aspect, an optical processing apparatus includes a focusing optical system that irradiates an object with processing light having a first wavelength as a peak wavelength and measurement light having a second wavelength different from the first wavelength, a processing optical system that causes the processing light from a processing light source to be incident on the focusing optical system, and a measurement device that causes the measurement light to be incident on the focusing optical system and into which detection light generated by the measurement light irradiated on the object is incident via the focusing optical system, wherein the focusing optical system passes the processing light and the measurement light directed to the object and includes a diffractive optical element on which the detection light generated by the measurement light irradiated on the object is incident, the diffractive optical element diffracts the processing light to generate m-th order diffracted light and diffracts the measurement light to generate n-th order diffracted light, and the first wavelength of the processing light and the second wavelength of the measurement light approximately satisfy a rational number relationship, where m and n are integers excluding 0.

[0008] According to a fifth aspect, an optical processing method includes irradiating an object with processing light having a first wavelength as a peak wavelength and measurement light having a second wavelength different from the first wavelength, detecting detection light generated by the measurement light irradiated on the object, passing the processing light and the measurement light toward the object through a diffractive optical element, passing the detection light from the object through the diffractive optical element, diffracting the processing light by the diffractive optical element to generate m-th order diffracted light, and diffracting the measurement light by the diffractive optical element to generate n-th order diffracted light, wherein when the first wavelength of the processing light is λ1 and the second wavelength of the measurement light is λ2, the optical processing method satisfies the conditional expression 0.96(m / n)<λ2 / λ1<1.04(m / n), where m and n are integers excluding 0.

[0009] According to a sixth aspect, the optical processing method includes irradiating an object with processing light having a peak wavelength of a first wavelength and measurement light having a peak wavelength of a second wavelength different from the first wavelength via a focusing optical system, and deflecting and scanning the processing light and the measurement light to make them incident on the focusing optical system, wherein making them incident on the focusing optical system includes moving an irradiation range of the processing light irradiated onto a diffractive optical element provided in the focusing optical system on the surface of the diffractive optical element, and changing the light amount of the processing light in accordance with the movement of the irradiation range.

[0010] FIG. 1 is a schematic diagram of an optical processing apparatus including a focusing optical system according to each embodiment. FIG. 2 is a diagram for explaining the deformation of the beam spot shape of processing light. FIG. 3(a) is a diagram showing the beam spot shape for each field of view position when a monochromatic laser is focused on an image plane by a focusing optical system according to each embodiment, which does not include a diffractive optical element. FIG. 3(b) is a diagram showing the beam spot shape for each field of view position when a laser having a spectral linewidth is focused on an image plane by a focusing optical system according to each embodiment, which does not include a diffractive optical element. FIG. 3(c) is a diagram for explaining the field of view position. FIG. 4(a) is an enlarged cross-sectional view of a blazed diffraction grating. FIG. 4(b) is an enlarged cross-sectional view of a multilevel diffraction grating. FIG. 5(a) is a diagram showing the beam spot shape for each field of view position when processing light is focused on an image plane by a focusing optical system according to each embodiment. FIG. 5(b) is a diagram showing the beam spot shape for each field of view position when measurement light is focused on an image plane by a focusing optical system according to each embodiment. FIG. 6 is a diagram showing the configuration of the focusing optical system according to the first embodiment. 7(a) and 7(b) are diagrams showing an optical design example of the focusing optical system according to the first embodiment. FIG. 8 is a diagram showing the configuration of the focusing optical system according to the second embodiment. FIG. 9(a) and 9(b) are diagrams showing an optical design example of the focusing optical system according to the second embodiment. FIG. 10 is a schematic diagram of an optical processing apparatus according to a modified example. FIG. 11 is a diagram for explaining that the diffraction efficiency of a diffractive optical element varies depending on the location. FIG. 12 is a diagram showing the hardware configuration of a control unit.

[0011] (Optical Processing Apparatus) FIG. 1 is a diagram schematically illustrating the configuration of an optical processing apparatus 1 including a focusing optical system 16 according to first and second embodiments described later. The X, Y, and Z directions indicated by arrows in FIG. 1 and the following figures are orthogonal to each other, and the X, Y, and Z directions indicate the same direction in each figure. The XZ direction indicated by the arrows in FIG. 1 is a direction intermediate between the X and Z directions described above, i.e., perpendicular to the Y direction and 45° away from the X and Z directions. Hereinafter, the directions indicated by the arrows will be referred to as the +X direction, +Y direction, +Z direction, and +XZ direction, respectively. The position in the X direction will be referred to as the X position, the position in the Y direction will be referred to as the Y position, and the position in the Z direction will be referred to as the Z position.

[0012] The optical processing apparatus 1 includes an optical device 2, a guide 20, a sample stage 19, and a control unit 200, all of which are shown within a dashed-line frame. The control unit 200 includes, as its functional components, a control unit (control device) 22, a measurement unit (measurement device) 23, a calculation unit (calculation device) 24, a position information correction unit (position information correction device) 25, and a processing light intensity control unit (processing light intensity control device) 31. The hardware configuration of the control unit 200 will be described later. The optical processing apparatus 1 uses the optical device 2 to focus a first light beam R1, which has a peak wavelength of a first wavelength and is emitted from a light source 10 serving as a processing light source, passes through a first optical path P1, and enters the optical device 2, onto an irradiated surface 17. A workpiece 18, which is an object to be processed, is placed on the sample stage 19, and the sample stage 19 positions the workpiece 18 so that a processing surface 18s of the workpiece 18 coincides with the irradiated surface 17 of the optical device 2.

[0013] The sample stage 19 is provided with a driving member such as a linear motor and moves on a guide 20 in at least one of the X and Y directions. The sample stage 19 may move the workpiece 18 along the Z direction (the optical axis direction of the focusing optical system 16). The optical device 2 may also be movable along the Z direction. A focus adjustment optical system (not shown) may be provided to change the focusing positions of the first light beam R1 and a second light beam R2 (described later) on the workpiece 18 along the Z direction.

[0014] In this case, the focus adjustment optical system may be arranged on a front-stage third optical path P3a (in other words, an optical path where the first optical path P1 and the second optical path P2 are superimposed) between the combining element 12 and the fixed mirror 13, which will be described later. Note that the focus adjustment optical system may be arranged on at least one of the optical paths, the first optical path P1 (described later) between the light source 10 and the combining element 12, and the second optical path P2 (described later) between the measurement unit 23 (measurement light source 23a) and the combining element 12.

[0015] The X, Y, and Z positions of the sample stage 19 are measured, for example, by an optical encoder 21, and the position information of the sample stage 19 is sent to the control unit 22 as a measurement signal S1. The control unit 22 sends a control signal S2 to the sample stage 19 based on the measurement signal S1, and sets the sample stage 19 to a desired position. The sample stage 19 can also be called a holder that holds the sample. Details of the measurement unit 23, calculation unit 24, position information correction unit 25, and processing light intensity control unit 31 will be described later.

[0016] The optical device 2 includes, in order from the light source 10 side to which the first light beam R1 having the first wavelength as its peak wavelength is supplied, a processing optical system 11, a combining element 12, a fixed mirror 13, an oscillating mirror 14, and a focusing optical system 16 shown in the frame surrounded by a dotted line.

[0017] The processing optical system 11 causes the first light beam R1 (processing light) from the light source 10 to be incident on the condensing optical system 16. The processing optical system 11 is an optical system that emits the first light beam R1 incident on the processing optical system 11 toward the combining element 12. In other words, the processing optical system 11 is an optical system that guides the first light beam R1 emitted from the light source 10 to the combining element 12. The first light beam R1 emitted from the processing optical system 11 is irradiated onto the illuminated surface 17 via the combining element 12 and the condensing optical system 16. Therefore, it can also be said that the processing optical system 11 is an optical system that emits (irradiates) the first light beam R1 toward the illuminated surface 17 via the combining element 12 and the condensing optical system 16.

[0018] The processing optical system 11 includes a position adjustment optical system 111. The position adjustment optical system 111 is capable of adjusting the emission position of the first light beam R1 from the processing optical system 11. The position adjustment optical system 111 may include, for example, a plane-parallel plate that can be tilted with respect to the traveling direction of the first light beam R1, and the emission position of the first light beam R1 may be changed by changing the tilt angle of the plane-parallel plate. In the example of FIG. 1 , the position adjustment optical system 111 can set the emission position of the first light beam R1 to any position within the YZ plane using multiple plane-parallel plates with different tilt directions. Changing the emission position of the first light beam R1 from the processing optical system 11 changes the incident angle of the first light beam R1 (e.g., the incident angle with respect to the irradiated surface 17). The processing optical system 11 may also include an angle adjustment optical system (not shown). The angle adjustment optical system is capable of adjusting the emission angle of the first light beam R1 from the processing optical system 11. The angle adjustment optical system may include, for example, a mirror that can be tilted with respect to the traveling direction of the first light beam R1, and the emission angle of the first light beam R1 may be changed by changing the tilt angle of the mirror. As an example, the angle adjustment optical system may use multiple mirrors with different tilt directions to set the emission angle of the first light beam R1 to any angle at which the first light beam R1 is emitted in any direction of rotation around the X axis and any direction of rotation around the Y axis. When the emission angle of the first light beam R1 from the processing optical system 11 changes, the irradiation position of the first light beam R1 (e.g., the irradiation position on the irradiated surface 17) changes.

[0019] The combining element 12 is an optical path combining member that combines the processing optical path along which the first light beam R1 (processing light) from the light source 10 travels and the measurement optical path along which the second light beam R2 (measurement light) from the measurement unit 23 (measurement light source 23a) travels.

[0020] A first light beam R1, which is supplied from the light source 10 as, for example, a parallel light beam and travels in the +Z direction, is incident on a processing optical system 11 that is made up of one or more lenses or mirrors and has a predetermined refractive power. The first light beam R1 that has exited the processing optical system 11 is incident on a combining element 12. Here, the refractive power of an optical system or optical element can be the reciprocal of the focal length of the optical system or optical element.

[0021] In this specification, the optical path of the first light beam R1 between the light source 10 and the combining element 12 is referred to as the first optical path P1. Therefore, it can be said that the processing optical system 11 is disposed on the first optical path P1. Note that the first optical path P1 is not limited to between the light source 10 and the combining element 12. For example, it can also be said that the first optical path P1 of the first light beam R1 is the optical path of the first light beam R1 traveling from the light source 10 to the workpiece 18 via the combining element 12, the fixed mirror 13, the oscillating mirror 14, and the focusing optical system 16 in the optical processing apparatus 1 (optical device 2). In other words, it can be said that the processing optical system 11 is disposed on the first optical path P1 on the incident side of the combining element 12, on which the first light beam R1 is incident.

[0022] In this specification, the optical path of the second light beam R2 between the measurement unit 23 (measurement light source 23a) and the combining element 12 is referred to as the second optical path P2. The measurement unit 23 in the control unit 200 includes a measurement light source 23a that emits the second light beam R2, a light receiving unit 23c (detection device) that receives the detection light (second light beam R2) returning from the workpiece 18, as described below, and a beam splitter 23b that separates and combines the light emitted from the measurement light source 23a and the light returning from the workpiece 18. The light receiving unit 23c is a light receiving element that can receive light and may typically be an optical-to-electrical conversion element. The beam splitter 23b may be a half mirror. In other words, the measurement unit 23 directs the second light beam R2 (measurement light) into the focusing optical system 16, and detection light generated by the measurement light irradiated on the workpiece 18 (target object) enters the measurement unit 23 via the focusing optical system 16.

[0023] The second optical path P2 is not limited to the path between the measurement unit 23 (measurement light source 23 a) and the combining element 12. For example, the second optical path P2 of the second light beam R2 can also be said to be the optical path of the second light beam R2 that travels from the measurement light source 23 a (measurement unit 23) to the workpiece 18 via the combining element 12, the fixed mirror 13, the oscillating mirror 14, and the focusing optical system 16 in the optical processing apparatus 1 (optical device 2).

[0024] A second light beam R2 is also incident on the combining element 12 from the measurement light source 23a (measurement unit 23) along a second optical path P2. The second light beam R2 has a peak wavelength at a second wavelength different from the first wavelength of the first light beam R1. More specifically, the second wavelength of the second light beam R2 is longer than the first wavelength of the first light beam R1. In the combining element 12, the first optical path P1 is combined with the second optical path P2 from the measurement light source 23a (measurement unit 23). Therefore, the first light beam R1 and the second light beam R2 are combined by the combining element 12 and become coaxial. The combining element 12 is, for example, a dichroic prism, and the dichroic reflecting surface 12r transmits the first light beam R1 having a peak wavelength at the first wavelength and reflects the second light beam R2 having a peak wavelength at a second wavelength different from the first wavelength.

[0025] The combining element 12 is not limited to the dichroic prism described above, and may be made of a flat glass plate having a dichroic mirror. Alternatively, if the first light beam R1 and the second light beam R2 are linearly polarized light beams whose polarization planes are approximately orthogonal to each other, a polarizing beam splitter may be used.

[0026] The first light beam R1 and the second light beam R2 combined by the combining element 12 are both emitted from the combining element 12 in the +Z direction and incident on the fixed mirror 13. The fixed mirror 13 is, for example, a plane mirror arranged along a plane parallel to the XZ direction and the Y direction. The first light beam R1 and the second light beam R2 traveling in the +Z direction and incident on the fixed mirror 13 are reflected by the fixed mirror 13 in the +X direction and incident on the oscillating mirror 14, which is a plane mirror. The first light beam R1 and the second light beam R2 reflected by the oscillating mirror 14 approximately in the +Z direction are incident on the condensing optical system 16.

[0027] In this specification, the optical path between the combining element 12 and the focusing optical system 16 is referred to as the third optical path P3. Therefore, it can be said that the fixed mirror 13 and the oscillating mirror 14 are disposed on the third optical path P3. In addition, within the third optical path P3, the section between the combining element 12 and the fixed mirror 13 is referred to as the front-stage third optical path P3a, the section between the fixed mirror 13 and the oscillating mirror 14 is referred to as the middle-stage third optical path P3b, and the section between the oscillating mirror 14 and the focusing optical system 16 is referred to as the rear-stage third optical path P3c. As described above, the first optical path P1 of the first light beam R1 can also be said to be the optical path of the first light beam R1 in the optical processing apparatus 1 that travels from the light source 10 to the workpiece 18 via the combining element 12, the fixed mirror 13, the oscillating mirror 14, and the focusing optical system 16.

[0028] The second optical path P2 of the second light beam R2 can also be said to be the optical path of the second light beam R2 that travels from the measurement light source 23a (measurement unit 23) toward the workpiece 18 via the combining element 12, the fixed mirror 13, the oscillating mirror 14, and the focusing optical system 16 in the optical processing apparatus 1. Therefore, the third optical path P3 can also be said to be an optical path in which the first optical path P1 of the first light beam R1 and the second optical path P2 of the second light beam R2 are at least partially superimposed. In other words, the fixed mirror 13 and the oscillating mirror 14 can also be said to be disposed on the first optical path P1 and the second optical path P2 between the combining element 12 and the focusing optical system 16.

[0029] The focusing optical system 16 irradiates the workpiece 18 (object) with a first light beam R1 (processing light) having a first wavelength as its peak wavelength and a second light beam R2 (measurement light) having a second wavelength different from the first wavelength. In this manner, in each embodiment, the processing light has a first wavelength range, and the first wavelength, which is the peak wavelength of the processing light, is the central wavelength of the processing light. The measurement light has a second wavelength range, and the second wavelength, which is the peak wavelength of the measurement light, is the central wavelength of the measurement light. The first wavelength range and the second wavelength range do not overlap with each other.

[0030] The focusing optical system 16 is an optical system including multiple lenses (G1 to G5) and a diffractive optical element DOE. The diffractive optical element DOE passes a first light beam R1 (processing light) and a second light beam R2 (measurement light) directed toward the workpiece 18 (object), and detection light from the workpiece 18 (object) is incident on the diffractive optical element DOE. The optical axis AX of the focusing optical system 16 is indicated by a dotted line in FIG. 1. The optical axis AX of the focusing optical system 16 may also be referred to as the optical axis of the exit side of the optical device 2. Of these, the lens G1, which is located closest to the entrance side, is, for example, a lens with negative refractive power. The lenses (G2 to G5) located closer to the irradiated surface 17 (downstream) than the lens G1 constitute a lens group with a positive refractive power as a whole.

[0031] The focusing optical system 16 includes a λ / 4 plate WPQ1, a λ / 4 plate WPQ2, and a dustproof window WDW, which are arranged on the exit side of the lens G5. The first light beam R1 and the second light beam R2 are generally focused on the illuminated surface 17 due to the refractive power of the focusing optical system 16. For convenience of explanation, the first light beam R1 and the second light beam R2 are described as being focused on the illuminated surface 17. However, the focusing positions of the first light beam R1 and the second light beam R2 do not have to be on the same plane (i.e., on the illuminated surface 17). FIG. 1 shows the focusing optical system 16 according to the first embodiment as an example. In the focusing optical systems 16 according to each embodiment, a diffractive optical element DOE is arranged behind the focusing optical system 16. Specifically, in the focusing optical system 16, the number of lenses arranged on the processing optical system 11 side (combining element 12 side) of the diffractive optical element DOE may be greater than the number of lenses arranged on the workpiece 18 side of the diffractive optical element DOE.

[0032] The oscillating mirror 14 is held by a driving member 15 so as to be oscillatable within a predetermined angle range around a rotation axis parallel to the Y direction, for example. As an example, a so-called galvanometer mirror may be used as the oscillating mirror 14 and the driving member 15. When the oscillating mirror 14 oscillates within a predetermined angle range around the Y direction as its center of rotation, the traveling directions of the first light beam R1 and the second light beam R2 reflected by the oscillating mirror 14 change (oscillate) between two directions in the ±X direction that are separated from the +Z direction by an angle twice the above-mentioned predetermined angle.

[0033] When the reflective surface of the oscillating mirror 14 is in the reference position, i.e., when the reflective surface is parallel to the Y direction and the XZ directions, the first light beam R1 and the second light beam R2 reflected by the oscillating mirror 14 pass through a central optical path P4a and are generally focused at a central focusing point Fa on the illuminated surface 17. When the oscillating mirror 14 rotates counterclockwise from the reference position about a rotation axis parallel to the Y direction, the first light beam R1 and the second light beam R2 reflected by the oscillating mirror 14 pass through a right optical path P4b and are generally focused at a right focusing point Fb on the illuminated surface 17 that is located on the +X side of the central focusing point Fa.

[0034] On the other hand, when the oscillating mirror 14 rotates clockwise from the reference position about a rotation axis parallel to the Y direction, the first light beam R1 and the second light beam R2 reflected by the oscillating mirror 14 pass through the left optical path P4c and are generally focused at a left light focusing point Fc located on the -X side of the central focusing point Fa on the irradiated surface 17. Therefore, the oscillating mirror 14 can also be considered a scanning optical member that deflects and scans the first light beam R1 (processing light) from the processing optical system 11 and the second light beam R2 (measurement light) from the measurement unit 23 (measurement light source 23a) and causes them to enter the focusing optical system 16. The oscillating mirror 14 deflects the first light beam R1 and the second light beam R2 and scans them within the irradiated surface 17. In other words, the oscillating mirror 14 moves the focusing positions of the processing light and the measurement light in a direction intersecting the optical axis.

[0035] The irradiation area of ​​the first light beam R1 (processing light) irradiated onto the diffractive optical element DOE moves on the surface of the diffractive optical element DOE in response to deflection scanning by the oscillating mirror 14 serving as a scanning optical member. Also, the irradiation area of ​​the second light beam R2 (measurement light) irradiated onto the diffractive optical element DOE moves on the surface of the diffractive optical element DOE in response to deflection scanning by the oscillating mirror 14 serving as a scanning optical member.

[0036] The focusing optical system 16 may also include an optical filter member (not shown) that changes the amount of light passing through depending on the position through which the light passes. The diffraction efficiency of the diffractive optical element DOE may vary depending on the location. For example, in Figure 11, the diffraction efficiency for light passing through region A of the diffractive optical element DOE may differ from the diffraction efficiency for light passing through region B of the diffractive optical element DOE. Typically, the diffraction efficiency is lower in areas away from the optical axis than in the vicinity of the optical axis.

[0037] For this reason, when the oscillating mirror 14 is rotated to scan the processing light, the fluence of the processing light may vary from place to place on the surface of the workpiece 18. If the fluence of the processing light varies from place to place, when removing the surface of the workpiece 18, the amount of removal (removal depth) in one portion will differ from the amount of removal (removal depth) in another portion.

[0038] In order to reduce this problem, it is preferable to dispose an optical filter element (typically an optical filter having a density distribution in which the attenuation rate increases toward the optical axis) whose light attenuation rate varies depending on the location at a position away from the pupil of the focusing optical system 16 (near the diffractive optical element DOE).

[0039] Alternatively, instead of or in addition to providing an optical filter member, the processing light amount control unit 31 may control at least one of the light source 10 and the processing optical system 11 to actively change the amount of processing light directed toward the focusing optical system 16. The processing light amount control unit 31 may change the amount of processing light in response to deflection scanning by the oscillating mirror 14 as a scanning optical member, i.e., may change the output of the light source 10 in synchronization with the galvano drive of the oscillating mirror 14. Specifically, the processing light amount control unit 31 may change the amount of processing light by changing the output of the light source 10 itself in synchronization with the galvano drive of the oscillating mirror 14, and / or may control an attenuation rate variable device (not shown) that is located at the exit of the light source 10 and within the processing optical system 11, and that can change the attenuation rate of the processing light, in synchronization with the galvano drive of the oscillating mirror 14.

[0040] The scanning optical member is not limited to a galvanometer mirror. For example, the scanning optical member may be an existing member capable of deflecting the first light beam R1 and the second light beam R2 from the combining element 12 and scanning the respective focusing points of the first light beam R1 and the second light beam R2 toward the workpiece 18 via the focusing optical system 16. For example, the scanning optical member may be a polygon mirror or an AOD (Acoustic Optical Deflector). The control unit 22 sends a control signal S3 to the driving member 15 to set the orientation of the oscillating mirror 14 to a predetermined orientation.

[0041] Hereinafter, the central optical path P4a, the right optical path P4b, and the left optical path P4c will be collectively or individually referred to as the fourth optical path P4. Also, the central focusing point Fa, the right focusing point Fb, and the left focusing point Fc will be collectively or individually referred to as the focusing point FP.

[0042] The focusing optical system 16 is, for example, a so-called fθ lens system. When the projection characteristic of the focusing optical system 16 is fθ, the distance from the central focusing point Fa to the right focusing point Fb or the left focusing point Fc on the illuminated surface 17 is proportional to the angle of deviation from the +Z direction of the traveling directions of the first light beam R1 and the second light beam R2 emitted from the oscillating mirror 14. In other words, the X position of the focusing point FP on the illuminated surface 17 is proportional to the rotation angle θ of the oscillating mirror 14 about the Y direction from the reference position described above. Note that the projection characteristic of the focusing optical system 16 is not limited to fθ. The projection characteristic of the focusing optical system 16 may be, for example, an equal solid angle projection characteristic or an orthogonal projection characteristic.

[0043] The first light beam R1 supplied from the light source 10 passes through the first optical path P1, the third optical path P3, and the fourth optical path P4 described above, and is irradiated onto the processing surface 18s of the workpiece 18 placed on the irradiation surface 17. The second light beam R2 emitted from the measurement light source 23a (measurement unit 23) passes through the second optical path P2, the third optical path P3, and the fourth optical path P4 described above, and is irradiated onto the processing surface 18s of the workpiece 18 placed on the irradiation surface 17. Note that, like the third optical path P3, the fourth optical path P4 can also be said to be an optical path in which the first optical path P1 of the first light beam R1 and the second optical path P2 of the second light beam R2 are at least partially overlapping.

[0044] In the optical processing apparatus 1, the first light beam R1 having a peak wavelength at the first wavelength is a light beam (processing light) for processing the workpiece surface 18s. In each embodiment, light having a peak wavelength of 517 nm is used as the processing light, which is the first light beam R1. That is, the first light beam R1 processes the workpiece surface 18s irradiated with the first light beam R1 by evaporating or melting the workpiece surface 18s itself (so-called removal processing), adding an object to the workpiece surface 18s (so-called addition processing), altering the workpiece surface 18s, or sensitizing, evaporating, or causing a chemical reaction in a film material formed on the workpiece surface 18s. Note that the first light beam R1 does not necessarily have to be a light beam for processing the workpiece surface 18s. For example, the first light beam R1 may be a light beam for measuring the workpiece surface 18s.

[0045] In the optical processing apparatus 1, the second light beam R2, which has a peak wavelength at the second wavelength, is a light beam (measurement light) for measuring the position of the workpiece surface 18s. In each embodiment, light having a peak wavelength of 1554.9 nm is used as the measurement light, which is the second light beam R2. The second light beam R2 is irradiated onto a portion of the workpiece surface 18s, and the second light beam R2, which is reflected or scattered by the workpiece surface 18s, travels through the fourth optical path P4 and the third optical path P3 and returns to the combining element 12. The second light beam R2 is then reflected by the dichroic reflecting surface 12r of the combining element 12, travels through the second optical path P2, and is received by the measurement unit 23 (light receiving unit 23c). The second light beam R2, which is reflected or scattered by the workpiece surface 18s and received by the measurement unit 23 (light receiving unit 23c), can also be referred to as detection light. Note that the second light beam R2 does not necessarily have to be a light beam for measuring the workpiece surface 18s. The second light beam R2 may be, for example, a light beam for processing the workpiece surface 18s. Note that if the first light beam R1 is a light beam for measuring the workpiece surface 18s, the second light beam R2 may be a light beam for processing the workpiece surface 18s. Note that although the second wavelength is longer than the first wavelength in this embodiment, the second wavelength may also be shorter than the first wavelength.

[0046] Information relating to the intensity of the detected light detected by the measurement unit 23 (light-receiving unit 23c) is sent to the calculation unit 24. The calculation unit 24 calculates position information relating to the portion of the workpiece surface 18s irradiated with the second light beam R2 based on the information relating to the intensity of the detected light detected by the measurement unit 23 (light-receiving unit 23c). The position information calculated by the calculation unit 24 is one or more of information relating to the X position, information relating to the Y position, and information relating to the Z position of the workpiece surface 18s.

[0047] The measurement unit 23 may include, for example, an interferometer. The three-dimensional shape measurement device disclosed in Japanese Patent No. 5231883 may be used as such a position measurement unit. The calculation unit 24 may also calculate position information regarding the workpiece surface 18s based on a signal S6 transmitted from the control unit 22, the signal S6 including position information regarding the sample stage 19 or information regarding the rotation angle of the oscillating mirror 14.

[0048] The position information of the workpiece surface 18s calculated by the calculation unit 24 may be the coordinates of the workpiece 18, a point cloud of multiple points included in the workpiece 18, or a three-dimensional model representing the workpiece 18. Instead of or in addition to the information regarding the position of the workpiece surface 18s, the measurement unit 23 may detect at least one of the shape of the workpiece surface 18s, the surface roughness of the workpiece surface 18s, the temperature of the workpiece surface 18s, the reflectance of the workpiece surface 18s, and the transmittance of the workpiece surface 18s.

[0049] 2 is a diagram for explaining that the beam spot shape of the first light beam R1 (processing light) is distorted because the first light beam R1 has a first wavelength range centered at a first wavelength. For simplicity, only one lens G5, which is closest to the illuminated surface 17, among the lenses included in the focusing optical system 16 is shown in FIG. 2 , and the diffractive optical element DOE is not provided. In other words, the following will be used to explain what would happen if the diffractive optical element DOE were not provided in the focusing optical system 16.

[0050] Although slight, chromatic aberration remains in the focusing optical system 16. For this reason, the focusing point FP of the first light beam R1 that passes through the fourth optical path P4 and is irradiated onto the illuminated surface 17 is separated into a first focusing point FP1 of the first light beam R1 at a certain wavelength λa and a second focusing point FP2 of the first light beam R1 at a wavelength λb different from the wavelength λa, because the first light beam R1 has a first wavelength range centered on the first wavelength. Note that this situation is similar for the second light beam R2 (measurement light) that has a second wavelength range centered on the second wavelength.

[0051] Hereinafter, the difference in position between the first focal point FP1 and the second focal point FP2 in the XY plane is referred to as chromatic aberration of magnification D1. Note that in FIG. 2, axial chromatic aberration, which is the difference in Z position between the first focal point FP1 and the second focal point FP2, is ignored. As described above, when the processing light (or measurement light) has a wavelength range, chromatic aberration of magnification occurs, and the spot shape of the laser beam is distorted, as shown in FIG. 3B (described later). If the spot shapes of the processing light and measurement light beams are distorted, accurate processing and measurement become impossible. Note that when the laser does not have a wavelength range (i.e., it is a monochromatic laser), the spot shape of the laser beam is maintained without distortion, as shown in FIG. 3A. Note that in FIG. 2, as an example, the surface on which the first focal point FP1 and the second focal point FP2 are formed is shown as the irradiated surface 17. The plane on which the first and second condensing points FP1 and FP2 are formed may be referred to as the image plane of the condensing optical system 16.

[0052] In the optical processing apparatus 1 according to each embodiment, the diffractive optical element DOE disposed in the focusing optical system 16 brings the position of the first condensing point FP1 of the first light beam R1 and the position of the second condensing point FP2 of the first light beam R1 near the irradiated surface 17 closer to each other. Therefore, compared to when the diffractive optical element DOE is not provided, when the diffractive optical element DOE is provided, the magnitude of the chromatic aberration of magnification D1 within the wavelength range of the processing light (or measurement light) described above is reduced, and the spot shape of the laser beam can be maintained. This makes it possible to improve the processing accuracy and degree of freedom of processing of the workpiece 18, as well as the measurement accuracy and degree of freedom of measurement of the workpiece 18.

[0053] Generally, due to chromatic aberration remaining in the focusing optical system 16, the angle φ1 of the chief ray R1p of the first light beam R1 of wavelength λa relative to the normal N1 of the irradiated surface 17 and the angle φ2 of the chief ray R2p of the first light beam R1 of wavelength λb relative to the normal N2 of the irradiated surface 17 may be different angles.

[0054] In the optical processing apparatus 1, the optical design of the optical device 2 is optimized so that the absolute values ​​of the angles φ1 and φ2 are both set to 2° or less. That is, even if the position of the fourth optical path P4 changes due to the oscillation of the oscillating mirror 14 to positions such as the central optical path P4a, the right optical path P4b, and the left optical path P4c shown in FIG. 1, the chief ray R1p and the chief ray R2p are incident on the irradiated surface 17 at an angle of incidence of 2° or less. Alternatively, the angles of the chief ray R1p of the first light beam R1 with wavelength λa and the chief ray R2p of the first light beam R1 with wavelength λb relative to the normal (Z direction) at their respective condensing positions can be stated as 2° or less. While the above description applies to the first light beam R1 (processing light), the same applies to the second light beam R2 (measurement light). Alternatively, the image side (the side of the processed surface 18s) of the optical device 2 (optical processing apparatus 1) can be stated as having a telecentric characteristic.

[0055] As a result, even if the workpiece surface 18s is positioned slightly displaced in the Z direction from the irradiated surface 17 due to unevenness or the like, the first light beam R1 can be irradiated onto the desired X and Y positions of the workpiece surface 18s, and the workpiece surface 18s can be accurately processed. Similarly, in the case of measurement light, the desired X and Y positions of the workpiece surface 18s can be accurately measured.

[0056] In addition, when the surface to be processed 18s has few irregularities, or when the surface to be processed 18s can always be accurately aligned with the irradiated surface 17, the angles of incidence of the chief ray R1p and the chief ray R2p on the irradiated surface 17 may be 2° or more. In this specification, the term "chief ray" may also refer to a line sequentially connecting the centers of gravity of the light quantities in the cross sections of the first light beam R1 (or the second light beam R2) at different Z positions.

[0057] Even when the first light beam (processing light) and the second light beam (measurement light) are incident on the same axis into the focusing optical system 16, the wavelengths of the processing light and the measurement light are different, and therefore, due to chromatic aberration of magnification between the processing light and the measurement light, the focusing position of the processing light and the focusing position of the measurement light will be shifted.

[0058] The optical processing apparatus 1 determines at least one of the irradiation position, the number of irradiations, and the irradiation conditions of the first light beam R1 on the surface 18s to be processed, based on the position information of the surface 18s to be processed, etc., detected and calculated by the measurement unit 23 and the calculation unit 24 using the second light beam R2. The number of irradiations of the first light beam R1 refers to the number of times the first light beam R1 is irradiated per unit time or the number of times the first light beam R1 is irradiated to a predetermined position on the surface 18s to be processed, etc., and the irradiation conditions of the first light beam R1 may include, for example, the intensity of the first light beam R1 or the wavelength of the first light beam R1.

[0059] However, the position information of the workpiece surface 18s detected and calculated by the measurement unit 23 and the calculation unit 24 is position information measured using the second light beam R2 of the second wavelength. Therefore, this position information includes an error of chromatic aberration of magnification between the processing light and the measurement light with respect to the position of the workpiece surface 18s based on the first light beam R1 of the first wavelength used for optical processing.

[0060] In the optical processing apparatus 1 and the optical device 2, the chromatic aberration of magnification occurring between the first light beam R1 and the second light beam R2 is reduced by optimizing the optical design of the optical device 2. However, the adverse effects of the chromatic aberration of magnification occurring between the first light beam R1 and the second light beam R2 may be further reduced by numerical correction using a position information correction unit 25 described below.

[0061] The position information corrector 25 is a unit that numerically corrects the chromatic aberration of magnification that occurs between the first light beam R1 and the second light beam R2. The position information corrector 25 receives a signal S8 from the controller 22, the signal S8 including information on the rotation angle of the oscillating mirror 14 or information on the X position of the focal point FP of the light beam traveling along the fourth optical path P4, which is determined by the rotation angle of the oscillating mirror 14.

[0062] The position information correcting unit 25 stores aberration information of the focusing optical system 16, which is numerical data indicating the relationship between the rotation angle of the oscillating mirror 14 or the X position of the focal point FP of the light beam traveling along the fourth optical path P4, and the chromatic aberration of magnification. The position information correcting unit 25 may also store information regarding the so-called telecentricity of the focusing optical system 16. Hereinafter, the aberration information and the information regarding telecentricity may be collectively referred to as information regarding the characteristics of the focusing optical system 16. The position information correcting unit 25 calculates the chromatic aberration of magnification at the focal point FP from the information regarding the characteristics of the focusing optical system 16, based on the information regarding the rotation angle of the oscillating mirror 14 or the information regarding the X position of the focal point FP sent from the control unit 22.

[0063] The position information correcting unit 25 corrects the position information of the workpiece surface 18s calculated by the calculating unit 24 and transmitted as signal S9, based on the chromatic aberration of magnification calculated as described above. Then, the position information correcting unit 25 returns the corrected position information of the workpiece surface 18s to the calculating unit 24 as signal S10.

[0064] Instead of correcting the position information itself of the workpiece surface 18s, the position information correcting unit 25 may return the amount by which the position information should be corrected as a signal S10 to the calculation unit 24. In this case, the calculation unit 24 may correct the position information of the workpiece surface 18s using the amount of correction transmitted from the position information correcting unit 25.

[0065] Furthermore, if the optical design of the optical device 2 is optimized so that the chromatic aberration of magnification occurring between the first light beam R1 and the second light beam R2 is kept sufficiently small, it is not necessary to provide the position information correction unit 25.

[0066] Lasers are ideally monochromatic, but as mentioned above, in reality they have a spectral linewidth, that is, a range of wavelengths centered around a peak wavelength.

[0067] 3A is a diagram showing the beam spot shape for each field of view position when a monochromatic laser with a wavelength of 517 nm is focused on an image plane using a general focusing optical system (e.g., the focusing optical system 16 according to the first embodiment minus the diffractive optical element DOE). Fig. 3B is a diagram showing the beam spot shape for each field of view position when a laser with a spectral linewidth obtained by wavelength-weighting the monochromatic laser with a wavelength of 517 nm to a full width at half maximum (FWHM) of 1.6 nm is focused on an image plane using a general focusing optical system (e.g., the focusing optical system 16 according to the first embodiment minus the diffractive optical element DOE).

[0068] 3(a) and 3(b), from top to bottom, the beam shape at the center of the field of view, the beam shape at a 50% field of view position, the beam shape at a 70% field of view position, and the beam shape at a 100% field of view position are shown. The 50%, 70%, and 100% field of view positions are positions that are 50%, 70%, and 100% of half the diagonal of the field of view from the center of the field of view, respectively, as shown in FIG.

[0069] As shown in Figure 3(a), when a monochromatic laser is used, the beam spot shape remains almost unchanged both at the center and at the periphery of the field of view. However, when a laser with a spectral linewidth is used, the beam spot shape becomes more noticeably distorted toward the periphery of the field of view, as shown in Figure 3(b). This is because, as the field of view becomes more peripheral, light with shorter wavelengths is deflected toward the center of the field of view, and light with longer wavelengths is deflected away from the center of the field of view. This is thought to be due to the influence of chromatic aberration of magnification described in Figure 2.

[0070] The refractive index of optical materials increases with shorter wavelengths in the visible light band and its vicinity. Therefore, for example, in a converging lens, the focal length changes depending on the wavelength, becoming shorter as the wavelength becomes shorter (positive dispersion). A common method for correcting this chromatic aberration is to combine a convex lens with a low dispersion and a concave lens with a high dispersion. However, in laser processing environments using high-power lasers, high-dispersion glass materials may be damaged. On the other hand, diffractive optical elements bend light rays through diffraction based on the phase distribution imparted by the shape of the diffractive optical element surface, rather than relying on the dispersion of the glass material of the diffractive optical element's substrate, resulting in a larger diffraction angle for light with longer wavelengths (negative dispersion). In other words, chromatic aberration can be corrected by combining a refractive lens with a converging diffractive optical element.

[0071] The inventors focused on the dispersion characteristics of such diffractive optical elements, which are not found in ordinary glass, and arranged a diffractive optical element DOE in the focusing optical system 16 of the optical processing device 1. As a result, as will be described in detail later, as shown in Figures 5(a) and 5(b), the spot shape of the light beam having a wavelength range remains almost unchanged even in the peripheral part of the field of view, and chromatic aberration of magnification within the wavelength range of the light beam can be corrected.

[0072] Fig. 4(a) is an enlarged cross-sectional view of a diffractive optical element DOE according to each embodiment. The diffractive optical element DOE shown in Fig. 4(a) is a blazed diffraction grating. In the optical processing apparatus 1, both the processing light, which is the first light beam R1, and the measurement light, which is the second light beam R2, enter the focusing optical system 16 and are irradiated onto the illuminated surface 17. For this reason, it is desirable that both the first light beam R1 and the second light beam R2 have high diffraction efficiency.

[0073] Here, let us consider the conditions under which m-th order diffracted light is blazed in a diffractive optical element DOE. In the diffractive optical element DOE shown in Figure 4(a), the angle of incidence of the light beam incident on the diffractive optical element DOE is θi, the angle of emergence of the light beam of m-th order diffracted light emerging from the diffractive optical element DOE is θm, the grating constant of the diffractive optical element DOE is dg, the blaze angle of the diffractive optical element DOE is φb, the refractive index of the diffractive optical element DOE is n1, the refractive index of air is n2, and the central wavelength of the light beam having a wavelength range is λ. In this case, the following equations (1) and (2) hold true: n1 sin(θi + φb) = n2 sin(θm + φb) (1) n2 sin(θm) = n1 sin(θi) + mλ / dg (2)

[0074] From the formulas (1) and (2), the following formula (3) can be derived: n2cos(θm)=n1cos(θi)+mλ / {dgtan(φb)} (3)

[0075] From this formula (3), it can be seen that a combination of m and λ where mλ satisfies a constant value can blaze the m-th order diffracted light by a diffractive optical element DOE of the same shape.

[0076] For example, if m=3 for light with a wavelength λ=500 nm and m=1 for light with a wavelength λ=1500 nm, mλ is constant, and in this case, the diffractive optical element DOE can blaze third-order diffracted light with m=3 for light with a wavelength λ=500 nm and first-order diffracted light with m=1 for light with a wavelength λ=1500 nm. In this case, the diffractive optical element DOE diffracts light with a wavelength λ=500 nm to generate third-order diffracted light and diffracts light with a wavelength λ=1500 nm to generate first-order diffracted light.

[0077] That is, in the focusing optical system 16 for irradiating the workpiece 18 with the processing light, which is the first light beam R1, and the measurement light, which is the second light beam R2, it is sufficient that the ratio λ2 / λ1 of the first wavelength λ1 of the processing light to the second wavelength λ2 of the measurement light is equal to the ratio m / n of the diffraction orders. However, in practice, the above-mentioned relationship does not need to be strictly satisfied, and a certain degree of freedom is allowed in selecting the peak wavelengths of the processing light and the measurement light. In other words, it is sufficient that the ratio λ2 / λ1 of the first wavelength λ1 of the processing light to the second wavelength λ2 of the measurement light is approximately equal to the ratio m / n of the diffraction orders. It can also be said that it is sufficient that the first wavelength of the processing light and the second wavelength of the measurement light approximately satisfy a rational number relationship.

[0078] Specifically, for a diffractive optical element DOE that diffracts processing light to generate m-th order diffracted light and diffracts measurement light to generate n-th order diffracted light, when the peak wavelength of the processing light is λ1 and the peak wavelength of the measurement light is λ2, it is sufficient if the following conditional expression (4) is satisfied, where m and n are integers excluding 0: 0.96(m / n)<λ2 / λ1<1.04(m / n) (4)

[0079] In each embodiment, the peak wavelength (first wavelength) λ1 of the processing light, which is the first light beam R1, is 517 nm, and the peak wavelength (second wavelength) λ2 of the measurement light, which is the second light beam R2, is 1554.9 nm. Therefore, λ2 / λ1 ≈ 3.008 ≈ 1.003 (m / n), which satisfies conditional expression (4), and sufficient diffraction efficiency (efficiency of 95% or more when λ2 / λ1 = m / n is strictly observed) can be maintained.

[0080] With the above configuration, the diffractive optical element DOE blazes the mth-order diffracted light for the processing light having a peak wavelength of λ1 and the nth-order diffracted light for the measurement light having a peak wavelength of λ2, thereby substantially satisfying the relationship λ2 / λ1 = m / n. This increases the diffraction efficiency of the processing light and the measurement light, corrects the chromatic aberration of magnification within the wavelength range of the processing light, and suppresses distortion of the beam spot shape of the processing light and the measurement light, even in the peripheral area of ​​the field of view. If the diffraction efficiency is poor, undiffracted light will become stray light and be detected by the measurement unit 23 (light-receiving unit 23c), preventing accurate measurement by the measurement unit 23 (light-receiving unit 23c). Therefore, the optical processing apparatus 1 according to each embodiment can improve the processing accuracy and flexibility of the workpiece 18, as well as the measurement accuracy and flexibility of the workpiece 18.

[0081] It is more preferable that the numerical range of conditional expression (4) is the range of the following conditional expression (4a): 0.98(m / n)<λ2 / λ1<1.02(m / n) (4a)

[0082] It is more preferable that the numerical range of conditional expression (4) be within the range of the following conditional expression (4b): 0.99(m / n)<λ2 / λ1<1.01(m / n) (4b)

[0083] While Fig. 4(a) shows a diffractive optical element DOE with a blazed diffraction grating, as shown in Fig. 4(b), the diffractive optical element DOE may be a multi-level diffraction grating in which the slope of each grating of the blazed diffraction grating is divided into a plurality of sections, each of which is a horizontal plane, thereby approximating the slope with a stepped surface shape. In a multi-level diffraction grating, the number of levels can be, for example, 2, 3, 4, 5, ..., 16, etc. Fig. 4(b) shows an example of a multi-level diffraction grating with four levels.

[0084] Furthermore, in the optical processing apparatus 1 according to each embodiment, when the effective diameter at the entrance surface of the diffractive optical element DOE is φE and the partial diameter at the entrance surface of the diffractive optical element DOE is φP, it is preferable to satisfy the following conditional expression (5): 0.17<φP / φE<0.23 (5) where the partial diameter φP is the minor diameter of the illuminated area at the entrance surface when a light beam heading toward an image point passes through the entrance surface.

[0085] The above conditional expression (5) indicates a condition under which the diffractive optical element DOE is disposed at a position closer to the image plane than to the pupil plane of the focusing optical system 16. By satisfying conditional expression (5), the chromatic aberration of magnification of the focusing optical system 16 can be effectively corrected by the diffractive optical element DOE. If φP / φE exceeds the upper limit of conditional expression (5), the diffractive optical element DOE is disposed close to the pupil plane of the focusing optical system 16, thereby weakening the chromatic aberration of magnification correction effect of the diffractive optical element DOE. On the other hand, if φP / φE is below the lower limit of conditional expression (5), the diffractive optical element DOE is disposed close to the image plane (or the surface of the workpiece 18), which may result in an excessively short working distance of the focusing optical system 16 or an excessively high energy density of the processing light passing through the diffractive optical element DOE, potentially damaging the diffractive optical element DOE.

[0086] It is more preferable that the numerical range of conditional expression (5) be within the range of the following conditional expression (5a): 0.175<φP / φE<0.225 (5a)

[0087] It is more preferable that the numerical range of conditional expression (5) be within the range of the following conditional expression (5b): 0.18<φP / φE<0.22 (5b)

[0088] 5A is a diagram showing the beam spot shape for each field of view position when a processing light laser having a first wavelength range obtained by wavelength-weighting a monochromatic laser having a peak wavelength of 517 nm to a full width at half maximum (FWHM) equivalent to 1.6 nm is focused on an image plane using the focusing optical system 16 according to the first embodiment. FIG. 5B is a diagram showing the beam spot shape for each field of view position when a measurement light laser having a second wavelength range obtained by wavelength-weighting a monochromatic laser having a peak wavelength of 1554.9 nm to a full width at half maximum (FWHM) equivalent to 16 nm is focused on an image plane using the focusing optical system 16 according to the first embodiment.

[0089] In Figures 5(a) and 5(b), as in Figures 3(a) and 3(b), the beam shape at the center of the field of view, the beam shape at a 50% field of view position, the beam shape at a 70% field of view position, and the beam shape at a 100% field of view position are shown, from top to bottom.

[0090] 5A and 5B, when the processing light and the measurement light are used, the beam spot shapes change little at all at the center and the periphery of the field of view. In other words, the chromatic aberration of magnification is corrected within the wavelength ranges of the processing light and the measurement light, and the deformation of the beam spot shapes of the processing light and the measurement light is suppressed even at the periphery of the field of view.

[0091] An example of the optical design of the light-collecting optical system 16 according to each embodiment will be described in detail below.

[0092] (Optical Design Example of Light-Concentrating Optical System 16 According to First Embodiment) Fig. 6 is a diagram showing the configuration of the light-concentrating optical system 16 according to the first embodiment. The light-concentrating optical system 16 shown in Fig. 6 roughly focuses the first light beam R1 and the second light beam R2 supplied from the light source 10 and the measurement unit 23 (measurement light source 23a), respectively, onto the illuminated surface 17.

[0093] The focusing optical system 16 according to the first embodiment is composed of a first lens G1, a second lens G2, a third lens G3, a fourth lens G4, a fifth lens G5, a diffractive optical element DOE, a first λ / 4 plate WPQ1, a second λ / 4 plate WPQ2, and a dustproof window WDW, arranged in this order from the light source 10 side to the workpiece surface 18s side.

[0094] 7A and 7B are diagrams showing an example of an optical design of the focusing optical system 16 according to the first embodiment. The table shown in Fig. 7A shows the radius of curvature R [mm], surface spacing D [mm], material of the optical component, effective diameter, and partial diameter of each surface of the optical components such as lenses that make up the focusing optical system 16, as defined by the surface number shown on the left side.

[0095] Of the surface numbers shown in FIG. 7A, surface number 1 indicates the entrance pupil surface, and surface number 20 indicates the image surface (irradiated surface 17).

[0096] The surface distance D represents the distance between the surface designated by the surface number and the next surface on the irradiated surface 17 side of that surface.

[0097] The material indicates the material of the optical member arranged between the surface designated by the surface number and the next surface on the illuminated surface 17 side of that surface. In the focusing optical system 16 according to the first embodiment, the first lens G1, the second lens G2, the third lens G3, the fifth lens G5, and the diffractive optical element DOE are made of silica (SILICA). The fourth lens G4 is made of fluorite (CAF2). The first λ / 4 plate WPQ1 and the second λ / 4 plate WPQ2 are made of quartz, and the dustproof window WDW is made of silica (SILICA).

[0098] The effective diameter is the diameter of a circle whose radius is the height from the optical axis of the ray of light passing through the lens surface that passes the farthest from the optical axis. The partial diameter is the minor axis of the illuminated area on the incident surface when a light beam heading toward an image point passes through the incident surface. The reason why the value of the partial diameter has a range is that, due to aberration caused by the lens placed in front of the diffractive optical element DOE, the diameter on the surface of the diffractive optical element DOE changes depending on the direction in which the beam is directed, even if the beam is focused with the same numerical aperture (NA) on the image plane.

[0099] As can be seen from the materials shown in FIG. 7A , the focusing optical system 16 according to the first embodiment is composed of almost all of its constituent optical components (lenses G1-G5 and diffractive optical element DOE) made of the same material, silica. Therefore, it is not an optical system that is ideally suited to correcting chromatic aberration of magnification within the wavelength ranges of the processing light and measurement light. However, the diffractive optical element DOE disposed in the focusing optical system 16 according to the first embodiment can bring the first focal point FP1 of the processing light (or measurement light) with wavelength λa and the second focal point FP2 of the first light beam R1 with wavelength λb near the irradiated surface 17 closer to each other, thereby correcting chromatic aberration of magnification within the wavelength range of the processing light. The focusing optical system 16 according to the first embodiment can also correct chromatic aberration of magnification within the wavelength range of the measurement light.

[0100] 7B is a table showing the phase distribution that the diffractive optical element DOE of the focusing optical system 16 according to the first embodiment imparts to light passing through the diffractive optical element DOE. The phase distribution imparted by the diffractive optical element DOE is expressed by the following equation (6). ...(6) where, r: distance from the center of the diffractive optical element DOE (unit: mm), φ: wavelength λ passing through a position at a distance r from the center of the diffractive optical element DOE. ０ The wavelength λ given to the light passing through the center of the diffractive optical element DOE ０ Phase difference [unit: rad] C ｎ : coefficient. The focal length EFL of the diffractive optical element DOE is EFL=-0.5 / C １ It is expressed as:

[0101] (Optical Design Example of Light-Concentrating Optical System 16 According to Second Embodiment) Fig. 8 is a diagram showing the configuration of the light-concentrating optical system 16 according to the second embodiment. The light-concentrating optical system 16 shown in Fig. 8 roughly focuses the first light beam R1 and the second light beam R2, which are supplied from the light source 10 and the measurement unit 23 (measurement light source 23a), respectively, onto the illuminated surface 17.

[0102] The focusing optical system 16 according to the second embodiment is composed of a first lens G1, a second lens G2, a third lens G3, a fourth lens G4, a diffractive optical element DOE, a fifth lens G5, a first λ / 4 plate WPQ1, a second λ / 4 plate WPQ2, and a dustproof window WDW, arranged in this order from the light source 10 side to the workpiece surface 18s side.

[0103] 9A and 9B are diagrams showing an example of an optical design of the focusing optical system 16 according to the second embodiment. The table shown in Fig. 9A shows the radius of curvature R [mm], surface spacing D [mm], material of the optical component, effective diameter, and partial diameter of each surface of the optical components such as lenses that make up the focusing optical system 16, as defined by the surface number shown on the left side.

[0104] Of the surface numbers shown in FIG. 9, surface number 1 indicates the entrance pupil surface, and surface number 20 indicates the image surface (irradiated surface 17).

[0105] The surface distance D represents the distance between the surface designated by the surface number and the next surface on the irradiated surface 17 side of that surface.

[0106] The material indicates the material of the optical member disposed between the surface designated by the surface number and the next surface on the illuminated surface 17 side of that surface. In the focusing optical system 16 according to the second embodiment, the first lens G1, the second lens G2, the third lens G3, the fourth lens G4, the fifth lens G5, and the diffractive optical element DOE are made of silica (SILICA). The first λ / 4 plate WPQ1 and the second λ / 4 plate WPQ2 are made of quartz, and the dustproof window WDW is made of silica (SILICA).

[0107] The effective diameter is the diameter of a circle whose radius is the height from the optical axis of the ray of light passing through the lens surface at the position farthest from the optical axis. The partial diameter is the minor axis of the illuminated area on the incident surface when a light beam heading toward an image point passes through the incident surface. The reason why the value of the partial diameter has a range is that the diameter on the surface of the diffractive optical element DOE changes depending on the direction in which the beam is directed, even if the beam is focused on the image plane with the same numerical aperture (NA).

[0108] As can be seen from the materials shown in FIG. 9A , the converging optical system 16, including all of its constituent optical components (lenses G1-G5 and diffractive optical element DOE), is made of the same material, silica. Therefore, it would not be an optical system that is suitable for correcting chromatic aberration of magnification within the wavelength ranges of the processing light and measurement light. However, the diffractive optical element DOE disposed in the converging optical system 16 according to the second embodiment can bring the first focal point FP1 of the processing light (or measurement light) with wavelength λa and the second focal point FP2 of the first light beam R1 with wavelength λb near the irradiated surface 17 closer to each other, thereby correcting chromatic aberration of magnification within the wavelength range of the processing light. The converging optical system 16 according to the second embodiment also corrects chromatic aberration of magnification within the wavelength range of the measurement light.

[0109] 9B is a table showing the phase distribution imparted to light passing through the diffractive optical element DOE of the focusing optical system 16 according to the second embodiment. The phase distribution imparted by the diffractive optical element DOE is expressed by the above formula (6).

[0110] (Effects of Optical Processing Apparatus 1 of Each Embodiment) The optical processing apparatus 1 of each embodiment described above includes a focusing optical system 16 that irradiates a workpiece 18 (object) with a first light beam R1 (processing light) having a first wavelength as a peak wavelength and a second light beam R2 (measurement light) having a second wavelength different from the first wavelength, a processing optical system 11 that causes the processing light from the light source 10 to enter the focusing optical system 16, and a measurement unit 23 that causes the measurement light to enter the focusing optical system 16 and into which detection light generated by the measurement light irradiated onto the workpiece 18 enters via the focusing optical system 16. The focusing optical system 16 includes a diffractive optical element DOE that passes the processing light and measurement light directed toward the workpiece 18 and into which the detection light from the workpiece 18 is incident. The diffractive optical element DOE diffracts the processing light to generate m-th order diffracted light and diffracts the measurement light to generate n-th order diffracted light. When the first wavelength of the processing light is λ1 and the second wavelength of the measurement light is λ2, the following condition is satisfied: 0.96(m / n)<λ2 / λ1<1.04(m / n), where m and n are integers excluding 0.

[0111] With this configuration, the diffractive optical element DOE blazes the m-th order diffracted light for the processing light with wavelength λ1 and the n-th order diffracted light for the measurement light with wavelength λ2, thereby increasing the diffraction efficiency of the processing light and the measurement light, correcting the chromatic aberration of magnification within the wavelength range of the processing light (and the chromatic aberration of magnification within the wavelength range of the measurement light), and suppressing distortion of the beam spot shape of the processing light (and the measurement light) even in the peripheral part of the field of view.As a result, the processing accuracy and degree of freedom of processing of the workpiece can be improved (and the measurement accuracy and degree of freedom of measurement of the workpiece can be improved).

[0112] The number of lenses constituting the focusing optical system 16 in each embodiment described above is not limited to the number mentioned above, and may have any other number of lenses, or may include a mirror.

[0113] Furthermore, the focusing optical system 16 according to each embodiment does not have a cemented lens in order to accommodate high-power lasers, but may instead be an optical system having a cemented lens.

[0114] The first wavelength used for optical processing and the second wavelength used for measurement are not limited to the wavelengths described above, and may be other wavelengths. For example, Gr light with a wavelength of approximately 500 nm may be used as the processing light, and near-infrared light with a wavelength of approximately 1000 nm may be used as the measurement light. In this case, the diffractive optical element DOE may be designed to diffract the processing light to generate second-order diffracted light and diffract the measurement light to generate first-order diffracted holes.

[0115] Furthermore, the materials of the first to fifth lenses G1 to G5 are not limited to the silica and fluorite mentioned above, but may be other light-transmitting materials.

[0116] The oscillating mirror 14 may not only oscillate about a rotation axis parallel to the Y direction as described above, but may also oscillate about a rotation axis parallel to the XZ directions. In this case, the position of the light-focusing point FP on the irradiated surface 17 can be moved not only in the X direction as described above, but also in the Y direction. Note that the oscillating mirror 14 may oscillate about a rotation axis parallel to the XZ directions instead of the Y direction. In this case, the position of the light-focusing point FP on the irradiated surface 17 can be moved in the Y direction.

[0117] If it is sufficient to adjust the relative positions of the workpiece 18 and the focal point FP in the X and Y directions by moving the sample stage 19 relative to the guide 20, the oscillating mirror 14 need not be provided.

[0118] In addition, when the oscillating mirror 14 is provided as described above, the X position (and also the Y position) of the focal point FP on the irradiated surface 17 can be moved at high speed. This allows the focal point FP to be moved at high speed on the processing surface 18s of the workpiece 18, and the processing capacity of the optical processing apparatus 1 can be further improved.

[0119] It should be noted that a swingable oscillating mirror may be disposed in place of the fixed mirror 13. In this case, the oscillating mirror replacing the fixed mirror 13 may swing about a rotation axis parallel to the XZ directions, and the oscillating mirror 14 may swing about a rotation axis parallel to the Y direction as described above. In this case, the first light beam R1 and the second light beam R2 are scanned in the X direction and the Y direction within the plane of the illuminated surface 17.

[0120] It should be noted that a plurality of oscillating mirrors may be disposed in the third optical path P3 (i.e., an optical path in which the first optical path P1 and the second optical path P2 are at least partially overlapped) in addition to the oscillating mirror 14. In this case, the fixed mirror 13 may be removed from the third optical path P3.

[0121] As described above, the optical processing apparatus 1 does not need to include the position information correction unit 25. Furthermore, the optical processing apparatus 1 does not need to include the calculation unit 24. When the calculation unit 24 is not included, the measurement unit 23 transmits information about the detected light intensity signal of the second light beam R2 to an external calculation unit (not shown), and the external calculation unit calculates the position information of the processing surface 18s.

[0122] The optical processing apparatus 1 may not have the light source 10. For example, the optical processing apparatus 1 may receive the first light beam R1 from a light source provided external to the optical processing apparatus 1 via a light-guiding member such as an optical fiber. The optical processing apparatus 1 may not have the measurement light source 23a. For example, the optical processing apparatus 1 may receive the second light beam R2 from a light source provided external to the optical processing apparatus 1 via a light-guiding member such as an optical fiber. The optical processing apparatus 1 may not have at least one of the control unit 22, the calculation unit 24, the position information correction unit 25, and the processing light amount control unit 31. For example, these may be provided external to the optical processing apparatus 1. At least one of the light source 10 and the measurement unit 23 may be included in the optical device 2. At least one of the control unit 22 and the calculation unit 24 may be included in the optical device 2.

[0123] In the above-described embodiments, the measurement unit 23 does not have to be an interference-based measurement device as described above. For example, the measurement unit 23 may be an optical coherence tomography (OCT) measurement device. An example of an OCT measurement device is described in Japanese Patent Application Publication No. 2020-101499. For example, the measurement unit 23 may be a measurement device equipped with a white light confocal displacement meter. An example of a white light confocal displacement meter is described in Japanese Patent Application Publication No. 2020-085633. For example, the measurement unit 23 may be a phase modulation-based measurement device. An example of a phase modulation-based measurement device is described in Japanese Patent Application Publication No. 2010-025922. For example, the measurement unit 23 may be an intensity modulation-based measurement device. Examples of intensity modulation-based measurement devices are described in Japanese Patent Application Publication No. 2016-510415 and U.S. Patent Application Publication No. 2014 / 226145.

[0124] In each of the embodiments described above, before processing the workpiece 18 with the first light beam R1, the optical processing device 1 may determine at least one of the irradiation position, number of irradiations, and irradiation conditions of the first light beam R1 on the workpiece surface 18s based on the position information of the workpiece surface 18s detected and calculated by the measurement unit 23 and the calculation unit 24 using the second light beam R2.

[0125] Furthermore, in each of the embodiments described above, after processing the workpiece surface 18s with the first light beam R1, the optical processing apparatus 1 may measure the portion processed with the first light beam R1 with the second light beam R2 and determine the acceptability and quality of the portion processed with the first light beam R1. For example, after processing the workpiece surface 18s with the first light beam R1, the optical processing apparatus 1 may calculate position information of the portion processed with the first light beam R1 and compare the calculated position information with predetermined reference position information (e.g., CAD data of the workpiece 18) to determine whether to reprocess the portion processed with the first light beam R1 or to end processing.

[0126] When re-processing the portion processed with the first light beam R1, the optical processing device 1 may determine at least one of the irradiation position, the number of irradiations, and the irradiation conditions of the first light beam R1 with respect to the workpiece surface 18s based on the position information of the portion processed with the first light beam R1, and re-process the portion processed with the first light beam R1. Furthermore, after processing the workpiece surface 18s with the first light beam R1, the optical processing device 1 may calculate position information of the portion processed with the first light beam R1, and compare the calculated position information with predetermined reference position information (e.g., CAD data of the workpiece 18) to determine whether the portion processed with the first light beam R1 has been processed into the desired shape.

[0127] In each of the embodiments described above, the optical processing device 1 may process the workpiece 18 with the first light beam R1 while measuring the workpiece 18 with the second light beam R2 (detecting the detection light from the workpiece surface 18s and calculating position information, etc.). In this case, processing and measurement of the workpiece 18 can be performed simultaneously.

[0128] In addition, when the optical processing device 1 simultaneously processes the workpiece 18 with the first light beam R1 and measures the workpiece 18 with the second light beam R2, it may detect the detection light from the workpiece surface 18s while processing the workpiece 18 with the first light beam R1, and calculate position information etc. based on the detection light after processing the workpiece 18 with the first light beam R1.

[0129] (Modification of Optical Processing Apparatus) Hereinafter, an optical processing apparatus 1a according to a modification will be described with reference to Fig. 10. The configuration of the optical processing apparatus 1a is generally the same as that of the optical processing apparatus 1 described above, and therefore, the same components are denoted by the same reference numerals and descriptions thereof will be omitted as appropriate.

[0130] The optical processing apparatus 1a according to the modified example differs from the optical processing apparatus 1 described above in that a variable mirror 26 is disposed on the second optical path P2 between the measurement unit 23 (measurement light source 23a) and the combining element 12. In the above-described embodiments, the first and second light beams R1 and R2 are coaxial, and the focusing positions of the first and second light beams R1 and R2 overlap. In this modified example, the azimuth angle of the reflecting surface of the variable mirror 26 is set to a predetermined angle, thereby shifting the position of the focusing point of the second light beam R2 relative to the focusing point of the first light beam R1 on the processing surface 18s of the workpiece 18 by a predetermined distance in the XY plane. The variable mirror 26 may be configured so that the azimuth angle of the reflecting surface can be set to a predetermined angle around an axis parallel to the Y direction. Although not shown in FIG. 10 , a relay optical system that conjugates the positional relationship between the variable mirror 26 and the oscillating mirror 14 may be disposed in the optical path from the variable mirror 26 to the oscillating mirror 14. In this case, it is possible to prevent the light beam from being blocked when the measurement light is deflected by the variable mirror 26, and also to suppress changes in telecentricity when the measurement light is incident on the workpiece surface 18s.

[0131] In the area where processing is being performed by irradiating the first light beam R1, there is a risk that measurement cannot be performed with high accuracy using the second light beam R2 due to fumes and the like generated from the surface 18s to be processed. In the optical processing device 1a of the modified example, information regarding the position or state of the surface 18s to be processed can be detected at a position different from the position processed by the first light beam R1, so that a decrease in measurement accuracy due to fumes and the like can be prevented.

[0132] The optical processing apparatus 1a of the modified example may process the workpiece 18 with the first light beam R1 while measuring the workpiece 18 with the second light beam R2. In this case, it is possible to simultaneously process and measure the workpiece 18 while preventing a decrease in measurement accuracy due to fumes, etc. In addition, when the optical processing apparatus 1a of the modified example simultaneously processes the workpiece 18 with the first light beam R1 and measures the workpiece 18 with the second light beam R2 (detecting detection light from the workpiece surface 18s and calculating position information, etc.), it is possible to detect detection light from the workpiece surface 18s while processing the workpiece 18 with the first light beam R1, and calculate position information, etc. based on the detection light after processing the workpiece 18 with the first light beam R1.

[0133] Instead of deflecting the second light beam R2 by the variable mirror 26 described above, for example, a relay lens system may be disposed on the second optical path P2, and a parallel plate glass may be disposed near the intermediate focal point formed by the relay lens system. In this case, by tilting the normal directions of the entrance surface and exit surface of the parallel plate glass from the traveling direction of the second light beam R2, the position of the focal point of the second light beam R2 on the workpiece surface 18s relative to the focal point of the first light beam R1 can be shifted by a predetermined distance in the XY plane direction.

[0134] In the optical processing apparatus 1a, the position where the variable mirror 26 is arranged is not limited to the second optical path P2 between the measurement unit 23 (measurement light source 23a) and the combining element 12. For example, the variable mirror 26 may be arranged in the first optical path P1 between the light source 10 and the combining element 12. Furthermore, in addition to the variable mirror 26 arranged in the second optical path P2 between the measurement unit 23 (measurement light source 23a) and the combining element 12, another variable mirror may be arranged in the first optical path P1 between the light source 10 and the combining element 12.

[0135] Furthermore, when the above-described relay optical system is disposed between the variable mirror 6 and the oscillating mirror 14, the position at which this relay optical system is disposed is not limited to the second optical path P2 between the measurement unit 23 (measurement light source 23 a) and the combining element 12. For example, the relay optical system that forms a conjugate relationship between the variable mirror 26 and the oscillating mirror 14 may be disposed in the first optical path P1 between the light source 10 and the combining element 12. Furthermore, in addition to the variable mirror 26 that is disposed in the second optical path P2 between the measurement unit 23 (measurement light source 23 a) and the combining element 12, a relay optical system that forms a conjugate relationship between another variable mirror and the oscillating mirror 14 may be disposed in the first optical path P1 between the light source 10 and the combining element 12.

[0136] In the above example, the combining element 12 has a dichroic reflecting surface 12r that transmits the first light beam R1 having a peak wavelength equal to the first wavelength and reflects the second light beam R2 having a peak wavelength equal to the second wavelength different from the first wavelength. However, the dichroic reflecting surface 12r may reflect the first light beam R1 having a peak wavelength equal to the first wavelength and transmit the second light beam R2 having a peak wavelength equal to the second wavelength different from the first wavelength.

[0137] Next, the hardware configuration of the control unit 200, which includes, as functional units, a control unit 22, a measurement unit 23, a calculation unit 24, a position information correction unit 25, and a processing light amount control unit 31, will be described with reference to Fig. 12. Fig. 12 is a block diagram showing the hardware configuration of the control unit 200.

[0138] 12 , the control unit 200 includes an arithmetic unit 201, a storage device 202, a communication device 203, a measurement light source 23 a, a beam splitter 23 b, and a light receiving unit 23 c. The arithmetic unit 201, the storage device 202, the communication device 203, the measurement light source 23 a, the beam splitter 23 b, and the light receiving unit 23 c may be connected via a data bus 206. Note that at least one of the measurement light source 23 a, the beam splitter 23 b, and the light receiving unit 23 c may be provided outside the control unit 200.

[0139] The arithmetic device 201 includes at least one processor (i.e., one processor or multiple processors) as hardware. The processor may include, for example, a processor conforming to a von Neumann computer architecture. The processor conforming to the von Neumann computer architecture may include at least one of a CPU (Central Processing Unit) and a GPU (Graphics Processing Unit). The processor may include, for example, a processor conforming to a non-von Neumann computer architecture. The processor conforming to the non-von Neumann computer architecture may include at least one of an FPGA (Field Programmable Gate Array) and an ASIC (Application Specific Circuit). Note that the arithmetic device 201 may be a circuit including a processor.

[0140] The arithmetic device 201 loads a computer program 221 including at least one of computer program code and computer program instructions. For example, the arithmetic device 201 may load the computer program 221 stored in the storage device 202. For example, the arithmetic device 201 may load the computer program 221 stored in a computer-readable, non-transitory storage medium using a storage medium reading device (not shown) included in the control unit 200. The computer program 221 read from the storage medium may be stored in the storage device 202. The arithmetic device 201 may acquire (i.e., download or load) the computer program 221 from a device (not shown) located outside the control unit 200 via the communication device 203 (or another communication device). The downloaded computer program 221 may be stored in the storage device 202.

[0141] The arithmetic device 201 executes the loaded computer program 221. As a result, logical functional blocks for executing the processing to be performed by the control unit 200 are realized within the arithmetic device 201. In other words, the arithmetic device 201, together with the storage device 202 or the like in which the computer program 221 is recorded (in other words, together with the storage device 202 and the computer program 221 recorded in the storage device 202 or the like), can function as a controller or computer for realizing the logical functional blocks for executing the processing to be performed by the control unit 200. In other words, the at least one processor included in the arithmetic device 201, the memory (recording medium) included in the storage device 202 or the like, and the computer program 221 are configured so that the control unit 200 performs the processing to be performed by the control unit 200.

[0142] A computational model that can be constructed by machine learning may be implemented in the computational device 201 by the computational device 201 executing the computer program 221. An example of a computational model that can be constructed by machine learning is a computational model including a neural network (so-called artificial intelligence (AI)). In this case, learning of the computational model may include learning of parameters of the neural network (for example, at least one of a weight and a bias). The computational device 201 may use the computational model to execute processing that should be performed by the control unit 200. Note that a computational model that has been constructed by offline machine learning using training data may be implemented in the computational device 201. Furthermore, the computational model implemented in the computational device 201 may be updated by online machine learning on the computational device 201. Alternatively, the calculation device 201 may execute the processing to be performed by the control unit 200 using a calculation model implemented in a device external to the calculation device 201 (i.e., a device provided outside the control unit 200) in addition to or instead of the calculation model implemented in the calculation device 201.

[0143] The recording medium for recording the computer program 221 executed by the arithmetic device 201 may be at least one of a CD-ROM, CD-R, CD-RW, flexible disk, MO, DVD-ROM, DVD-RAM, DVD-R, DVD+R, DVD-RW, DVD+RW, Blu-ray (registered trademark), or other optical disk, a magnetic medium such as a magnetic tape, a magneto-optical disk, a semiconductor memory such as a USB memory, or any other medium capable of storing a program. The recording medium may include a device capable of recording the computer program 221 (for example, a general-purpose device or a dedicated device in which the computer program 221 is implemented in a state in which it can be executed in at least one of the forms of software and firmware). Furthermore, each process or function included in the computer program 221 may be realized by a logical processing block realized within the arithmetic device 201 when the arithmetic device 201 (i.e., processor) executes the computer program 221, 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 arithmetic device 201, or may be realized in a form that mixes logical processing blocks and partial hardware modules that realize some elements of the hardware.

[0144] Fig. 12 shows an example of logical functional blocks realized in the arithmetic device 201 to execute the processing to be performed by the control unit 200. As shown in Fig. 12, the arithmetic device 201 realizes a control unit 22, a measurement unit 23, a calculation unit 24, a position information correction unit 25, and a processing light amount control unit 31. Furthermore, each functional block may be a control unit including a arithmetic device, a storage device, and a communication device.

[0145] The storage device 202 includes at least one memory capable of storing desired data. In other words, the storage device 202 includes at least one memory containing desired data. For example, the storage device 202 may store a computer program 221 executed by the arithmetic device 201. In this case, the storage device 202 (memory) may be used as the above-mentioned recording medium for recording the computer program 221 executed by the arithmetic device 201. The storage device 202 may temporarily store data used by the arithmetic device 201 when the arithmetic device 201 is executing the computer program 221. The storage device 202 may store data that the control unit 200 will store for a long period of time. The storage device 202 may include at least one of a RAM (Random Access Memory), a ROM (Read Only Memory), a hard disk device, a magneto-optical disk device, an SSD (Solid State Drive), and a disk array device. That is, the storage device 202 may include a non-transitory recording medium. Note that the storage device 202 may be a circuit including a memory.

[0146] The present invention is not limited to the above. Other aspects conceivable within the scope of the technical idea of ​​the present invention are also included in the scope of the present invention. This embodiment may combine all or part of the above aspects.

[0147] REFERENCE SIGNS LIST 1...optical processing device, 2...optical device, P1...first optical path, P2...second optical path, P3...third optical path, P4...fourth optical path, R1...first light beam, R2...second light beam, 10...light source, 11...processing optical system, 12...combining element, 13...fixed mirror, 14...oscillating mirror, 16...focusing optical system, G1...first lens, G2...second lens, G3...third lens, G4...fourth lens, G5...fifth lens, DOE...diffractive optical element, WPQ1...first λ / 4 plate, WPQ2...second λ / 4 plate, WDW...dustproof window, 17...irradiated surface, 18...workpiece, 18s...processed surface, 19...sample stage, 20...guide, 22...controller, 23...measuring unit, 24...calculating unit, 25...positional information correcting unit, 31...processing light amount controller

Claims

1. An optical processing device comprising: a focusing optical system that irradiates an object with processing light having a first wavelength as a peak wavelength and measurement light having a second wavelength different from the first wavelength; a processing optical system that causes the processing light from a processing light source to enter the focusing optical system; and a measurement device that causes the measurement light to enter the focusing optical system and into which detection light generated by the measurement light irradiated onto the object enters via the focusing optical system, wherein the focusing optical system passes the processing light and the measurement light directed toward the object and comprises a diffractive optical element onto which the detection light from the object is incident, the diffractive optical element diffracts the processing light to generate m-th order diffracted light and diffracts the measurement light to generate n-th order diffracted light, wherein where the first wavelength of the processing light is λ1 and the second wavelength of the measurement light is λ2, the optical processing device satisfies the conditional expression 0.96(m / n)<λ2 / λ1<1.04(m / n), where m and n are integers excluding 0.

2. The optical processing device according to claim 1, wherein the following condition is satisfied: 0.98(m / n)<λ2 / λ1<1.02(m / n), where m and n are integers excluding 0, where m and n are integers excluding 0, where n is the first wavelength of the processing light and λ2 is the second wavelength of the measurement light.

3. The optical processing device according to claim 2, wherein the following condition is satisfied: 0.99(m / n)<λ2 / λ1<1.01(m / n), where m and n are integers excluding 0, where m and n are integers excluding 0, where n is the first wavelength of the processing light and λ2 is the second wavelength of the measurement light.

4. An optical processing device according to any one of claims 1 to 3, wherein the processing light has a first wavelength range, the measurement light has a second wavelength range, the first wavelength is the central wavelength of the processing light, and the second wavelength is the central wavelength of the measurement light.

5. The optical processing device according to claim 4, wherein the first wavelength range and the second wavelength range do not overlap each other.

6. An optical processing device according to any one of claims 1 to 5, comprising a scanning optical element that deflects and scans the processing light from the processing optical system and the measurement light from the measurement device, causing them to enter the focusing optical system.

7. The optical processing device according to claim 6, wherein the irradiation range of the processing light irradiated onto the diffractive optical element moves on the surface of the diffractive optical element in response to deflection scanning by the scanning optical member.

8. The optical processing device according to claim 7, wherein the focusing optical system includes an optical filter member that changes the amount of light passing through depending on the position through which the light passes.

9. An optical processing device as described in claim 7 or 8, comprising a processing light quantity control device that controls at least one of the processing light source and the processing optical system to actively change the quantity of the processing light directed toward the focusing optical system, and the processing light quantity control device changes the quantity of the processing light in accordance with deflection scanning by the scanning optical element.

10. An optical processing device according to any one of claims 1 to 9, which satisfies the condition: 0.17<φP / φE<0.23, where φE is the effective diameter at the entrance surface of the diffractive optical element, and φP is the partial diameter at the entrance surface of the diffractive optical element, where the partial diameter is the minor axis of the irradiated area at the entrance surface when a light beam heading toward an image point passes through the entrance surface.

11. The optical processing device according to claim 10, which satisfies the condition: 0.175<φP / φE<0.

225.

12. The optical processing device according to claim 11, which satisfies the condition: 0.18<φP / φE<0.

22.

13. An optical processing device according to any one of claims 1 to 12, further comprising an optical path combining member that combines a processing optical path along which the processing light from the processing light source travels and a measurement optical path along which the measurement light from the measurement device travels.

14. The optical processing device according to claim 13, wherein the optical path combining member makes the processing light and the measurement light coaxial.

15. An optical processing device according to any one of claims 1 to 14, wherein the diffractive optical element is disposed behind the focusing optical system.

16. An optical processing device as described in claim 15, wherein the number of lenses arranged on the processing optical system side of the diffractive optical element in the focusing optical system is greater than the number of lenses arranged on the object side of the diffractive optical element.

17. An optical processing device according to any one of claims 1 to 16, wherein the diffractive optical element is a blazed diffraction grating.

18. An optical processing device according to any one of claims 1 to 17, wherein the diffractive optical element is a multi-level diffraction grating in which the slope of each grating of a blazed diffraction grating is divided into multiple sections, each section being a horizontal plane, thereby approximating the slope with a stepped surface shape.

19. An optical processing device according to any one of claims 1 to 18, wherein the angle of the chief ray of the processing light relative to the normal at the focusing position and the angle of the chief ray of the measurement light relative to the normal at the focusing position are 2° or less.

20. An optical processing device according to any one of claims 1 to 19, wherein the measurement device further comprises a detection device that detects the detection light generated by the measurement light irradiated onto the object via the focusing optical system.

21. The optical processing device according to claim 20, further comprising a calculation device that calculates position information relating to the position of the portion of the object irradiated with the processing light based on the detection light detected by the detection device.

22. The optical processing device according to claim 21, wherein the processing light is irradiated based on the position information.

23. An optical processing device comprising: a focusing optical system that irradiates an object with processing light having a first wavelength as a peak wavelength and measurement light having a second wavelength different from the first wavelength; a processing optical system that causes the processing light from a processing light source to enter the focusing optical system; a measurement device that causes the measurement light to enter the focusing optical system and into which detection light generated by the measurement light irradiated onto the object enters via the focusing optical system; a scanning optical element that deflects and scans the processing light from the processing optical system and the measurement light from the measurement device and causes them to enter the focusing optical system; wherein the focusing optical system comprises a diffractive optical element that passes the processing light and the measurement light directed toward the object and into which the detection light from the object is incident; the irradiation range of the processing light irradiated onto the diffractive optical element moves on the surface of the diffractive optical element in accordance with the deflection scanning by the scanning optical element; and the focusing optical system comprises an optical filter element that changes the amount of light passing depending on the position where the light passes.

24. A focusing optical system that irradiates an object with processing light having a first wavelength as a peak wavelength and measurement light having a second wavelength different from the first wavelength; a processing optical system that causes the processing light from a processing light source to enter the focusing optical system; a measurement device that causes the measurement light to enter the focusing optical system and into which detection light generated by the measurement light irradiated onto the object enters via the focusing optical system; a scanning optical element that deflects and scans the processing light from the processing optical system and the measurement light from the measurement device and causes them to enter the focusing optical system; and a processing light amount control device that controls at least one of the processing light source and the processing optical system to actively change the amount of processing light directed toward the focusing optical system, wherein the focusing optical system includes a diffractive optical element that allows the processing light and the measurement light directed toward the object to pass through and into which the detection light from the object is incident, and the irradiation range of the processing light irradiated onto the diffractive optical element moves on the surface of the diffractive optical element in accordance with the deflection scanning by the scanning optical element, The processing light amount control device changes the amount of the processing light in accordance with deflection scanning by the scanning optical member.

25. An optical processing apparatus comprising: a focusing optical system that irradiates an object with processing light having a first wavelength as its peak wavelength and measurement light having a second wavelength different from the first wavelength; a processing optical system that causes the processing light from a processing light source to enter the focusing optical system; and a measurement device that causes the measurement light to enter the focusing optical system and into which detection light generated by the measurement light irradiated onto the object enters via the focusing optical system, wherein the focusing optical system passes the processing light and the measurement light directed toward the object and comprises a diffractive optical element onto which detection light generated by the measurement light irradiated onto the object is incident, the diffractive optical element diffracts the processing light to generate m-th order diffracted light and diffracts the measurement light to generate n-th order diffracted light, wherein the first wavelength of the processing light and the second wavelength of the measurement light approximately satisfy a rational number relationship, where m and n are integers excluding 0.

26. An optical processing method comprising: irradiating an object with processing light having a peak wavelength of a first wavelength and measurement light having a peak wavelength of a second wavelength different from the first wavelength; detecting detection light generated by the measurement light irradiated on the object; passing the processing light and the measurement light directed toward the object through a diffractive optical element; passing the detection light from the object through the diffractive optical element; diffracting the processing light by the diffractive optical element to generate m-th order diffracted light; and diffracting the measurement light by the diffractive optical element to generate n-th order diffracted light, wherein where the first wavelength of the processing light is λ1 and the second wavelength of the measurement light is λ2, the optical processing method satisfies the conditional expression 0.96(m / n)<λ2 / λ1<1.04(m / n), where m and n are integers excluding 0.

27. An optical processing method comprising: irradiating an object with processing light having a first wavelength as a peak wavelength and measurement light having a second wavelength different from the first wavelength via a focusing optical system; deflecting and scanning the processing light and the measurement light to make them incident on the focusing optical system; wherein making the processing light and the measurement light incident on the focusing optical system comprises moving an irradiation range of the processing light that is irradiated onto a diffractive optical element included in the focusing optical system on the surface of the diffractive optical element; and changing the amount of light of the processing light in accordance with the movement of the irradiation range.

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