Foreign substance inspection device and foreign substance inspection method

Abstract

To provide a foreign substance inspection device that performs foreign substance inspection according to a user's demand for throughput and sensitivity.SOLUTION: A foreign substance inspection device has: a first light shaping unit that shapes first light; a second light shaping unit that shapes second light having a major axis along a movement direction longer than the first light in an irradiation shape in an object to be measured; and a light switching mechanism that, when the foreign substance inspection on the object to be measured is completed and foreign substance inspection on the subsequent object to be measured is started, can switch light to be emitted to the object to be measured to the first light or the second light.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a foreign matter inspection device and a foreign matter inspection method. [Background technology]

[0002] 2. Description of the Related Art Conventionally, there is a foreign matter inspection device that inspects the surface of a measurement object for foreign matter by irradiating the measurement object with light and detecting the light from the measurement object.

[0003] As shown in Patent Document 1, for example, this type of foreign matter inspection device includes a light irradiation unit that irradiates inspection light onto the front and back surfaces of a substrate, which is the object to be measured, a light detection unit that detects reflected and scattered light emitted from the front and back surfaces of the substrate, and a computing unit that receives light detection signals from the light detection unit and detects foreign matters on the substrate.With the substrate moving in a direction perpendicular to the scanning direction of the inspection light, the light irradiation unit irradiates the front and back surfaces of the substrate with the inspection light while scanning, thereby detecting foreign matters present on the front and back surfaces of the substrate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-145141 Summary of the Invention [Problem to be solved by the invention]

[0005] In this type of foreign particle inspection device, when the light irradiation unit irradiates the substrate with light, the inspection light is incident at a predetermined angle with respect to the front and back surfaces of the substrate, resulting in an elliptical shape with the major axis aligned with the direction of movement of the substrate.

[0006] Here, if the long axis of the irradiation shape is small, the sensitivity in foreign particle inspection improves, but the substrate feed pitch becomes small, resulting in a decrease in throughput. Some users prioritize throughput over sensitivity in foreign particle inspection, but with the above-mentioned foreign particle inspection device, the long axis of the irradiation shape is constant, making it difficult to improve throughput. Therefore, in the past, a single foreign particle inspection device could not perform foreign particle inspection according to the user's needs for throughput and sensitivity.

[0007] It is also possible to improve throughput by increasing the mirror oscillation speed (scanning frequency) of the light irradiation unit, which indicates the scanning speed of the inspection light. However, there is a limit to how fast the mirror oscillation speed can be increased, and increasing the mirror oscillation speed too much reduces the light detection signal, making it difficult to improve throughput by changing the mirror oscillation speed.

[0008] The present invention has been made in view of the above problems, and has as its main object to enable a single foreign substance inspection apparatus to perform foreign substance inspection in accordance with user demands for throughput and sensitivity. [Means for solving the problem]

[0009] That is, the foreign matter inspection device of the present invention includes a light irradiation unit that irradiates a measurement object that is moving relatively along a predetermined movement direction with light in a direction intersecting the movement direction, a light detection unit that detects light from the measurement object when light is irradiated onto the measurement object from the light irradiation unit, and a calculation unit that detects foreign matters in the measurement object based on a light detection signal from the light detection unit, and the light irradiation unit has a first light shaping unit that emits first light, a second light shaping unit that emits second light that is different from the first light, and a light switching mechanism that switches the light to be emitted to the measurement object between the first light and the second light when foreign matter inspection of the measurement object is completed and foreign matter inspection of the next measurement object is started, and is characterized in that in the irradiation shape on the measurement object, the major axis of the first light and the major axis of the second light are along the movement direction, and the major axis of the second light is longer than the major axis of the first light.

[0010] With this configuration, when the foreign substance inspection of a measurement object is completed and the foreign substance inspection of the next measurement object is started, the light switching mechanism can switch the light emitted to the measurement object between the first light and the second light, so the measurement time required for the foreign substance inspection can be set according to the type of measurement object. Specifically, since the major axis of the second light is longer than the major axis of the first light in the irradiation shape of the measurement object, when the second light is emitted to the measurement object, the feed pitch of the measurement object can be increased and the measurement time can be shortened. On the other hand, when the first light is emitted to the measurement object, the sensitivity can be improved. Therefore, foreign substance inspection can be performed according to the required throughput and sensitivity. In addition, when the second light is emitted toward the object to be measured, the major axis of the second light is longer than the major axis of the first light in the irradiation shape of the object to be measured, so that the throughput can be improved without increasing the oscillation speed (scanning frequency) of the mirror of the light irradiation unit, which indicates the scanning speed of the inspection light.

[0011] The first light shaping unit and the second light shaping unit are configured to introduce the laser light from a common laser light source, and the light switching mechanism switches between a state in which the laser light from the laser light source is introduced into the first light shaping unit and a state in which the laser light from the laser light source is introduced into the second light shaping unit depending on the type of the object to be measured.

[0012] With this configuration, by using a common laser light source for the first light shaping unit and the second light shaping unit, the number of parts in the light irradiation unit can be reduced when switching the light emitted to the object to be measured, compared to when there are multiple laser light sources, and the light irradiation unit can be made cheaper.

[0013] The light irradiation unit preferably further includes a light scanning unit that scans the first light from the first light shaping unit and the second light from the second light shaping unit over the object to be measured in a direction intersecting the movement direction, and the light switching mechanism preferably includes an incident side mirror provided between the laser light source and the first light shaping unit or the second light shaping unit, an exit side mirror provided between the first light shaping unit or the second light shaping unit and the light scanning unit, and a switching actuator that moves the incident side mirror and the exit side mirror to switch between a first light path, which is the light path from the laser light source via the first light shaping unit to the light scanning unit, and a second light path, which is the light path from the laser light source via the second light shaping unit to the light scanning unit.

[0014] With this configuration, the switching actuator switches between the first optical path and the second optical path by moving the incident side mirror and the exit side mirror, so there is no need to move the first light shaping unit and the second light shaping unit when switching light, which makes it possible to save space in the light irradiation unit. Furthermore, by using a common light scanning unit for the first light shaping unit and the second light shaping unit, the number of components in the light irradiation unit can be reduced compared to when multiple light scanning units are used, and the light irradiation unit can be made cheaper.

[0015] In addition, as a configuration for further achieving space saving in the light irradiation unit, the first light shaping unit and the light scanning unit are provided on the optical path of the laser light emitted from the laser light source, the incident side mirror reflects the laser light from the laser light source toward the second light shaping unit, and the exit side mirror reflects the second light from the second light shaping unit toward the light scanning unit, and the switching actuator retracts the incident side mirror and the exit side mirror from the optical path of the laser light emitted from the laser light source to form the first optical path, and positions the incident side mirror and the exit side mirror on the optical path of the laser light emitted from the laser light source to form the second optical path.

[0016] The second light shaping section preferably shapes the second light by guiding the laser light from a laser light source to a plurality of optical members.

[0017] With this configuration, the second light is shaped by introducing laser light from the laser light source into multiple optical elements, so the second light can be shaped more easily than when only one optical element is used.

[0018] The second light shaping section preferably shapes the second light by expanding the laser light from the laser light source in the entire circumferential direction and then expanding it in one direction.

[0019] With this configuration, the second light is shaped by expanding the laser light from the laser light source in the entire circumferential direction and then expanding it in one direction, so the second light can be shaped more simply and clearly compared to when it is expanded in one direction first.

[0020] A specific configuration of the second light shaping unit is one in which the laser light from a laser light source is introduced into a magnifying lens and then introduced into an optical element including at least a cylindrical lens, thereby shaping the second light.

[0021] The foreign matter inspection device is configured to sequentially inspect the plurality of measurement objects for foreign matters, and the light switching mechanism is configured to switch the light emitted to the measurement objects when foreign matter inspection of one measurement object is completed and foreign matter inspection of the next measurement object is started.

[0022] With this configuration, the light switching mechanism switches the light when the foreign substance inspection of one measurement object is completed and the foreign substance inspection of the next measurement object is started, so the measurement time can be switched to an appropriate time for each measurement object, thereby shortening the time required to inspect multiple measurement objects for foreign substances.

[0023] Here, in order to inspect the entire surface of the object to be measured without omissions, the long axis of the irradiation shape on the surface of the object to be measured needs to be longer than the feed pitch in the direction of movement of the object to be measured. However, since the long axis of the second light is longer than the long axis of the first light, it is desirable that the feed pitch in the direction of movement of the object to be measured, where the second light is irradiated, is larger than the feed pitch in the direction of movement of the object to be measured, where the first light is irradiated.

[0024] With this configuration, the speed in the direction of movement of the measurement object irradiated with the second light is greater than the speed in the direction of movement of the measurement object irradiated with the first light, so that when the second light is irradiated onto the measurement object, the time required to inspect the entire surface of the measurement object can be shortened.

[0025] A foreign body inspection method includes irradiating a measurement object that is moving relatively along a predetermined movement direction with light, detecting the light from the measurement object when the light is irradiated onto the measurement object, and detecting foreign bodies in the measurement object based on the light detected from the measurement object, wherein, when irradiating the measurement object with light, when foreign body inspection of the measurement object is completed and foreign body inspection of the next measurement object is started, the light to be emitted to the measurement object is switched to a first light or a second light that is different from the first light, and the illumination shape on the measurement object has a major axis of the first light and a major axis of the second light aligned along the movement direction, and the major axis of the second light is longer than the major axis of the first light.

[0026] With this configuration, it is possible to obtain the same effects as those of the above-described foreign matter inspection device. [Effects of the Invention]

[0027] According to the present invention, one foreign substance inspection device can perform foreign substance inspection in accordance with the user's demands for throughput and sensitivity. [Brief explanation of the drawings]

[0028] [Figure 1]1 is a schematic diagram showing a foreign matter inspection device according to an embodiment of the present invention; [Figure 2] FIG. 3 is a schematic diagram showing a light irradiation unit in the embodiment. [Figure 3] 10A shows the cross-sectional shape of the irradiation when the first light is emitted, and FIG. 10B shows the shape of the irradiation on the surface of the object to be measured when the first light is emitted, in the same embodiment. [Figure 4] 10A shows the cross-sectional shape of the irradiation when the second light is emitted, and FIG. 10B shows the shape of the irradiation on the surface of the object to be measured when the second light is emitted, in the same embodiment. [Figure 5] FIG. 10 is a schematic diagram showing a light irradiation unit according to another embodiment of the present invention. [Figure 6] FIG. 10 is a schematic diagram showing a light irradiation unit according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0029] A foreign particle inspection device according to one embodiment of the present invention will be described below with reference to the drawings. Note that in all of the drawings shown below, some parts may be omitted or exaggerated as needed for clarity. Identical components will be assigned the same reference numerals, and their description will be omitted as needed.

[0030] <Device configuration> The foreign matter inspection apparatus 100 of this embodiment inspects for foreign matters present on the surface of a plate-shaped measurement object W, such as a substrate, wafer, and / or pellicle. The foreign matter referred to here refers to dirt or dust present on the surface of the measurement object W, and / or defects formed on the surface of the measurement object W (for example, scratches and / or electrostatic breakdown of a pattern, or, if the measurement object W is a pellicle, pinholes and / or tears formed on the surface of the measurement object W).

[0031] 1, the foreign matter inspection device 100 includes a stage 2 on which a measurement object W is placed, a light irradiation unit 3 that irradiates light onto the measurement object W, a light detection unit 4 that detects light from the measurement object W when light is irradiated onto the measurement object W from the light irradiation unit 3, and a calculation device 5 that inspects the measurement object W for foreign matters based on a light detection signal from the light detection unit 4. The configuration of each unit will be described below.

[0032] The stage 2 can be moved in a predetermined direction by a drive unit (not shown) including a motor, etc. In this embodiment, a measurement object W is placed on the stage 2, and the stage 2 moves linearly in the predetermined direction, whereby the measurement object W also moves linearly along the movement direction.

[0033] The light irradiating unit 3 is placed on the stage 2 and irradiates the surface of the measurement object W, which is moving along a predetermined movement direction, with light while scanning it. The light irradiating unit 3 irradiates the surface of the measurement object W with light at a predetermined angle. The light irradiating unit 3 scans light in a direction intersecting (specifically, a direction perpendicular to) the movement direction of the measurement object W, so that the foreign matter inspection device 100 is configured to be able to inspect almost the entire surface of the measurement object W placed on the stage 2. The specific configuration of the light irradiating unit 3 will be described later.

[0034] The light detection unit 4 converts information such as the intensity, frequency, and / or phase of light from the measurement object W when the light is irradiated onto the measurement object W from the light irradiation unit 3 into an electrical signal and outputs this as a light detection signal to the calculation device 5. In this embodiment, the light detection unit 4 detects scattered light from the surface of the measurement object W and outputs it as a light detection signal. The light detection unit 4 may be a detector such as a PMT (photomultiplier tube) and / or a line sensor. The light detection unit 4 may further include an optical element, such as a lens and / or a slit, interposed between the surface of the measurement object W and the detector to collect the light from the measurement object W.

[0035] The arithmetic unit 5 receives the light detection signal from the light detection unit 4 and inspects whether or not a foreign substance is present on the surface of the measurement object W. Specifically, the arithmetic unit 5 determines whether or not the light detection signal from the light detection unit 4 is equal to or greater than a predetermined threshold, and if the light detection signal from the light detection unit 4 is equal to or greater than the predetermined threshold, determines that a foreign substance is present on the surface of the measurement object W. The arithmetic unit 5 is configured as a general-purpose or dedicated computer including a CPU (not shown), internal memory, external memory (not shown), input / output interface, communication interface for communicating with the stage 2, scanning mirror, etc., an AD converter, etc., and the CPU and its peripheral devices operate based on a foreign substance inspection program stored in a predetermined area of ​​the internal memory or external memory to perform foreign substance inspection.

[0036] <Configuration of light irradiation unit 3> As shown in Figure 2, the light irradiation unit 3 has a laser light source 31 that emits laser light, a first light shaping unit 32 that shapes the first light, a second light shaping unit 33 that shapes the second light, which is light whose major axis along the movement direction of the measurement object W in the irradiation shape on the measurement object W is longer than the first light, a light scanning unit 34 that scans the measurement object W with the first light or the second light in a direction intersecting (specifically, a direction perpendicular to) the movement direction of the measurement object W, and a light switching mechanism 35 that switches the light irradiated on the measurement object W to the first light or the second light depending on the type of the measurement object W.

[0037] The laser light source 31 is, for example, a HeNe laser light source or the like, and is a light source common to the first light shaping unit 32 and the second light shaping unit 33. The laser light source 31 may be provided separately for the first light shaping unit 32 and the second light shaping unit 33.

[0038] The first light shaping unit 32 shapes the first light by expanding the laser light from the laser light source 31, and is, for example, a beam expander. In this embodiment, the first light shaping unit 32, together with the light scanning unit 34 described later, is provided on the same linear optical path of the laser light emitted from the laser light source 31. Specifically, the first light shaping unit 32 expands the laser light from the laser light source 31 over the entire circumferential direction.

[0039] As a result, as shown in FIG. 3(a), the cross-sectional shape of the first light emitted from the optical scanning unit 34, cut perpendicular to the optical path of the first light, is approximately circular, and in this embodiment, it is a perfect circle. Here, the major axis of the cross-sectional shape of the first light is the diameter of the perfect circle. Then, by irradiating the surface of the measurement object W with the first light at a predetermined angle, the cross-sectional shape of the first light on the surface of the measurement object W becomes approximately elliptical, as shown in FIG. 3(b), with the major axis of the first light aligned along the movement direction. Note that in this embodiment, the first light shaping unit 32 uniformly expands the laser light from the laser light source 31, but it may also expand in one direction. Furthermore, the cross-sectional shape of the first light is not limited to a perfect circle and may be other shapes.

[0040] The second light shaping unit 33 shapes the second light by guiding the laser light from the laser light source 31 into a plurality of optical members. In this embodiment, the second light shaping unit 33 is provided in parallel to the first light shaping unit 32. Specifically, the second light shaping unit 33 has a front-stage optical member 33a that expands the laser light from the laser light source 31 over the entire circumferential direction, and a rear-stage optical member 33b that expands the light from the front-stage optical member 33a in one direction.

[0041] The front optical member 33a is, for example, a beam expander such as a magnifying lens, and here, uniformly expands the laser light from the laser light source 31. Note that the front optical member 33a may also expand the laser light from the laser light source 31 in one direction.

[0042] The rear optical member 33b is a beam expander that expands in one direction using, for example, a cylindrical lens, and shapes the second light by expanding the light from the front optical member 33a in one direction. Here, the rear optical member 33b expands the light from the front optical member 33a only in the direction in which the major axis along the movement direction of the irradiation shape on the surface of the measurement object W when the second light is irradiated onto the surface of the measurement object W becomes longer.

[0043] As a result, as shown in FIG. 4(a), the cross-sectional shape of the second light, cut perpendicular to the optical path of the second light emitted from the optical scanning unit 34, becomes a roughly elliptical shape having a longer major axis than the major axis of the first light (specifically, the diameter of the first light) in the cross-sectional shape of the first light. Then, by irradiating the surface of the measurement object W with the second light at a predetermined angle, as shown in FIG. 4(b), the cross-sectional shape of the second light on the surface of the measurement object W becomes a roughly elliptical shape, with the major axis of the second light aligned with the movement direction and longer than the major axis of the first light. As a result, the feed pitch V2 in the movement direction of the measurement object W when the second light is irradiated can be made larger than the feed pitch V1 in the movement direction of the measurement object W when the first light is irradiated. The cross-sectional shape of the second light is not limited to an elliptical shape, as long as it has a longer major axis than the cross-sectional shape of the first light.

[0044] In addition, as shown in FIGS. 3(b) and 4(b), in the irradiation shape of the first light and the irradiation shape of the second light on the surface of the measurement object W, the minor axis of the first light (here, since the irradiation shape of the first light is a perfect circle, it is the diameter of the perfect circle) and the minor axis of the second light are approximately the same length. That is, the irradiation shape of the second light on the surface of the measurement object W is approximately elliptical in that only the major axis along the movement direction of the measurement object W is longer than the irradiation shape of the first light on the surface of the measurement object W. With this configuration, it is possible to suppress a decrease in the sensitivity and S / N ratio of foreign substance inspection compared to when the irradiation shape of the second light is simply made larger. Note that the irradiation cross-sectional shape of the second light is not limited to an elliptical shape as long as it has a longer major axis than the irradiation cross-sectional shape of the first light.

[0045] The optical scanning unit 34 scans the first light or the second light over the surface of the measurement object W. In this embodiment, in order to focus the light on the surface of the measurement object W, the optical scanning unit 34 has a scanning mirror (not shown), such as a galvanometer mirror, and a scanning lens (not shown), such as an fθ lens. In this embodiment, the scanning direction of the optical scanning unit 34 is a direction perpendicular to the movement direction of the measurement object W, but it may be any direction that intersects at least with the movement direction of the measurement object W.

[0046] The light switching mechanism 35 switches between a state in which the laser light from the laser light source 31 is introduced into the first light shaping unit 32 and a state in which the laser light from the laser light source 31 is introduced into the second light shaping unit 33, depending on the type of measurement object W. Here, the type of measurement object W is set based on the user's demands for sensitivity and throughput of foreign substance inspection. When the user sets the type of measurement object W, a control unit (not shown) receives the setting signal, and the control unit controls the light switching mechanism 35 based on the setting signal. Note that the control unit here is a general-purpose or ordinary computer, and may be the same computer as the arithmetic device 5 or a different computer.

[0047] Specifically, as shown in FIG. 2, the light switching mechanism 35 has an incident side mirror 351 provided between the laser light source 31 and the first light shaping unit 32 and / or the second light shaping unit 33, an exit side mirror 352 provided between the first light shaping unit 32 and / or the second light shaping unit 33 and the light scanning unit 34, and a switching actuator 353 that switches between a state in which the laser light is introduced into the first light shaping unit 32 (first introduction state) and a state in which the laser light is introduced into the second light shaping unit 33 (second introduction state) by moving the incident side mirror 351 and the exit side mirror 352.

[0048] The incident side mirror 351 reflects the laser light from the laser light source 31 toward the second light shaping unit 33. In this embodiment, the incident side mirrors 351 are a pair of mirrors whose reflective surfaces face each other. One incident side mirror 351 is moved by a switching actuator 353 and reflects the laser light from the laser light source 31 to the other incident side mirror 351. The other incident side mirror 351 is fixed and reflects the laser light from the one incident side mirror 351 to guide it to the second light shaping unit 33.

[0049] The exit side mirror 352 reflects the second light from the second light shaping unit 33 toward the light scanning unit 34. In this embodiment, the exit side mirrors 352 are a pair of mirrors whose reflective surfaces face each other. One exit side mirror 352 is fixed and reflects the second light from the second light shaping unit 33 to the other exit side mirror 352. The other exit side mirror 352 is moved by a switching actuator 353 and reflects the second light from the one exit side mirror 352 to introduce it into the light scanning unit 34.

[0050] The switching actuator 353 is a driving member such as a solenoid, an air cylinder, and / or a motor. The switching actuator 353 of this embodiment is a rack-and-pinion type that transmits rotation of a motor to a rack gear via a pinion gear. More specifically, the switching actuator 353 moves an X-direction moving member X, which has a rack gear extending along the X direction and moves in the X direction, and a Y-direction moving member Y, on which the incident-side mirror 351 and the exit-side mirror 352 are mounted and which moves in the Y direction, thereby moving the incident-side mirror 351 and the exit-side mirror 352. Here, the X direction refers to the direction in which the laser light source 31 emits laser light, and the Y direction refers to the direction perpendicular to the X direction and in which the incident-side mirror 351 and the exit-side mirror 352 move.

[0051] The X-direction moving member X is, for example, in the shape of a flat plate, and is configured to be movable in the X direction by transmitting the rotation of the switching actuator 353 to a rack gear. The X-direction moving member X is formed with a groove G that extends at an angle with respect to the X direction.

[0052] The Y-direction moving member Y is, for example, in the shape of a flat plate, and moves in the Y direction in response to movement of the X-direction moving member X in the X direction. Specifically, the Y-direction moving member Y has a pair of mounting portions Y1 on which the incident-side mirror 351 and the exit-side mirror 352 are respectively mounted, and a connecting portion Y2 that connects the pair of mounting portions Y1. The connecting portion Y2 is formed with a protrusion P that fits into a groove G of the X-direction moving member X. As the groove G moves in the X direction, the protrusion P moves along the groove G in the Y direction, thereby enabling the Y-direction moving member Y to move in the Y direction.

[0053] <Foreign substance inspection method> Next, a foreign matter inspection method using the foreign matter inspection device 100 of this embodiment will be described. The foreign matter inspection method of this embodiment sequentially inspects a plurality of measurement objects W for foreign matters. Specifically, in the foreign matter inspection method, after foreign matter inspection of one measurement object W is completed, foreign matter inspection of the next measurement object W is performed.

[0054] First, the measurement object W is placed on the stage 2. At this time, the user sets the type of the measurement object W. The control unit receives a setting signal indicating the type of the measurement object W and controls the light switching mechanism 35.

[0055] Specifically, when foreign matter inspection is performed on measurement target W where sensitivity takes priority over throughput, switching actuator 353 moves incident side mirror 351 and exit side mirror 352 in the Y direction toward second light shaping unit 33, and retracts incident side mirror 351 and exit side mirror 352 from the optical path of the laser light emitted from laser light source 31. This results in a state (first introduction state) in which the laser light is introduced into first light shaping unit 32, and a first optical path is formed, which is an optical path from laser light source 31 via first light shaping unit 32 to optical scanning unit 34.

[0056] When laser light is emitted from the laser light source 31 with the first optical path formed, the laser light is expanded by the first light shaping unit 32 to shape the first light. Then, with the measurement object W moving along a predetermined movement direction, the light scanning unit 34 scans the first light at a predetermined angle with respect to the surface of the measurement object W in a direction intersecting the movement direction of the measurement object W. The irradiation cross-sectional shape of the first light is, for example, a perfect circle, and the irradiation shape of the first light on the surface of the measurement object W is approximately elliptical. This allows the entire surface of the measurement object W to be scanned with the first light, enabling highly sensitive foreign body inspection.

[0057] When the entire surface of the measurement object W has been scanned with the first light, foreign substance inspection of that measurement object W is completed. Then, foreign substance inspection of the next measurement object W is started. Here, the next measurement object W is a measurement object W for which throughput takes priority over sensitivity. When that measurement object W is placed on the stage 2, the switching actuator 353 moves the incident side mirror 351 and the exit side mirror 352 in the Y direction toward the first light shaping unit 32, and positions the incident side mirror 351 and the exit side mirror 352 on the optical path of the laser light emitted from the laser light source 31. This brings the laser light into a state (second introduction state) in which it is introduced into the second light shaping unit 33, and a second optical path is formed, which is an optical path from the laser light source 31 via the second light shaping unit 33 to the optical scanning unit 34.

[0058] When the laser light source 31 emits laser light while the second optical path is formed, the laser light is expanded in the entire circumferential direction by the front optical member 33a. The expanded laser light is then expanded in one direction by the rear optical member 33b, and the second light is shaped.

[0059] While the measurement object W is moving in a predetermined movement direction, the optical scanning unit 34 scans the surface of the measurement object W with the second light in a direction intersecting the movement direction of the measurement object W at a predetermined angle. The irradiation cross-sectional shape of the second light is approximately elliptical, and the irradiation shape of the second light on the surface of the measurement object W is approximately elliptical in which the major axis along the movement direction of the measurement object W is longer than that of the first light. This allows the entire surface of the measurement object W to be scanned with the second light, enabling foreign substance inspection with improved throughput.

[0060] In the above-described foreign matter inspection method, foreign matter inspection of the measurement object W that prioritizes sensitivity is performed first, and then foreign matter inspection of the measurement object W that prioritizes throughput is performed, but the order in which the types of measurement object W are inspected for foreign matter may be reversed, or may be changed as appropriate by the user.

[0061] <Effects of this embodiment> According to the foreign matter inspection device 100 of this embodiment, when foreign matter inspection of a measurement object W is completed and foreign matter inspection of the next measurement object W is started, the light switching mechanism 35 can switch the light emitted to the measurement object W between the first light and the second light. This makes it possible to set the measurement time required for foreign matter inspection according to the type of measurement object W. Specifically, since the major axis of the second light along the movement direction of the irradiation shape of the measurement object W is longer than that of the first light, when the second light is emitted to the measurement object W, the feed pitch of the measurement object W can be increased and the measurement time can be shortened. On the other hand, when the first light is emitted to the measurement object W, sensitivity can be improved. Therefore, foreign matter inspection can be performed according to required throughput and sensitivity.

[0062] Furthermore, the front-stage optical member 33a and the rear-stage optical member 33b are lenses such as a beam expander and a cylindrical lens, respectively, so the amount of light of the second light can be made sufficient compared to when, for example, an aperture and / or a slit is used.

[0063] <Other embodiments> The present invention is not limited to the above-described embodiment.

[0064] In the above embodiment, the incident-side mirror 351 and the exit-side mirror 352 are removed from the optical path of the laser light from the laser light source 31 when the first optical path is formed. However, they may be located in the optical path of the laser light from the laser light source 31. For example, as shown in Fig. 5, the incident-side mirror 351 may be composed of a first incident-side mirror 351a that reflects the laser light from the laser light source 31 toward the first light shaping unit 32, and a second incident-side mirror 351b that reflects the laser light from the laser light source 31 toward the second light shaping unit 33. Furthermore, the exit-side mirror 352 may be composed of a first exit-side mirror 352a that reflects the first light from the first light shaping unit 32 toward the optical scanning unit 34, and a second exit-side mirror 352b that reflects the second light from the second light shaping unit 33 toward the optical scanning unit 34.

[0065] Here, the first incident side mirror 351a and the second incident side mirror 351b are placed on a table T1 that is movable in the Y direction. The first exit side mirror 352a and the second exit side mirror 352b are also placed on a table T2 that is movable in the Y direction. In FIG. 5, the table T1 and the table T2 are separate tables, but they may be a common table.

[0066] 5, when foreign substance inspection is performed on the measurement object W, which requires sensitivity more than throughput, the light switching mechanism 35 moves the tables T1 and T2 in the Y direction toward the first light shaping unit 32, thereby forming a first optical path through which the laser light is introduced into the first light shaping unit 32. On the other hand, when foreign substance inspection is performed on the measurement object W, which requires throughput more than sensitivity, the light switching mechanism 35 moves the tables T1 and T2 in the Y direction toward the second light shaping unit 33, thereby forming a second optical path through which the laser light is introduced into the second light shaping unit 33.

[0067] In the above embodiment, the switching actuator 353 switches between the first introduction state and the second introduction state by moving the incident-side mirror 351 and the exit-side mirror 352, but this is not limiting. For example, as shown in FIG. 6 , the first light shaping unit 32 and the second light shaping unit 33 may be placed on a table T3 that is movable in the Y direction, and the switching actuator 353 (not shown) may switch between the first introduction state and the second introduction state by moving the table T3 in the Y direction. Alternatively, a partition plate or switch that blocks the laser light from the laser light source 31 may be provided between the first light shaping unit 32 and the laser light source 31 and / or between the second light shaping unit 33 and the laser light source 31. Even in such a configuration, the light switching mechanism 35 switches between the first introduction state and the second introduction state depending on the type of measurement object W, so that the measurement time can be changed depending on the required sensitivity and throughput.

[0068] In the above embodiment, the second light shaping unit 33 shapes the second light using a plurality of optical elements, but it is sufficient if the second light is shaped using at least one optical element that expands in one direction. Even in such a case, the illumination shape of the second light on the surface of the measurement target W has a longer major axis in the movement direction than the illumination shape of the first light.

[0069] In the above embodiment, the front optical member 33a expands the laser light in the entire circumferential direction, and the rear optical member 33b expands the laser light from the front optical member 33a in one direction, but this is not limited to this. For example, the front optical member 33a may expand the laser light in one direction, and the rear optical member 33b may expand the laser light from the front optical member 33a in the entire circumferential direction. Even in this case, the irradiation shape of the second light on the surface of the measurement target W has a longer major axis in the movement direction than the irradiation shape of the first light.

[0070] In the above embodiment, the stage 2 on which the measurement object W is placed moves, causing the measurement object W to move relatively to the light irradiation unit 3. However, the foreign matter inspection device 100 may not include the stage 2, and the light irradiation unit 3 may move relative to the measurement object W. Even in such a configuration, the measurement object W can move relatively to the light irradiation unit 3.

[0071] In the above embodiment, the light switching mechanism 35 switches the light to be irradiated onto the measurement object W between the first light and the second light, but the light switching mechanism 35 may also switch the light to be irradiated onto the measurement object W between three or more lights. For example, the light irradiating unit 3 may have a third light shaping unit that shapes the third light different from the first light shaping unit 32 and the second light shaping unit 33, and the light switching mechanism 35 may switch the light to be irradiated onto the measurement object W between the first light, the second light, and the third light.

[0072] In the above embodiment, the first light shaping unit 32 is, for example, a beam expander that shapes the first light by expanding the laser light from the laser light source 31, but the first light shaping unit 32 may be any unit that shapes the first light so that the major axis is shorter than that of the second light in the irradiation shape on the measurement object W. For example, the first light shaping unit 32 may be an optical element that shapes the laser light without expanding it, or the first light shaping unit 32 may be one that directly emits the laser light from the laser light source 31 without including any optical element.

[0073] In addition, the present invention can be modified in various ways without departing from the spirit of the invention. [Explanation of symbols]

[0074] 100 Foreign body inspection device 2 Stage 3. Light irradiation unit 31 Laser light source 32...1st light shaping section 33...Second light shaping section 34 Optical scanning unit 35 Optical switching mechanism 351....Input mirror 352 Exit mirror 353···Switching actuator 4. Light detection unit 5...Arithmetic unit

Claims

1. a light irradiation unit that irradiates a measurement object that is moving relatively along a predetermined movement direction with light in a direction intersecting the movement direction; a light detection unit that detects light from the object to be measured when the object to be measured is irradiated with light from the light irradiation unit; a calculation unit that detects foreign matter in the measurement object based on the light detection signal from the light detection unit, The light irradiation unit a first light shaping unit that shapes the first light; a second light shaping unit that shapes second light that is different from the first light; a light switching mechanism that switches the light to be emitted to the measurement object between the first light and the second light when the foreign substance inspection of the measurement object is completed and the foreign substance inspection of the next measurement object is started, a major axis of the first light and a major axis of the second light are aligned along the movement direction in an irradiation shape on the measurement object, and the major axis of the second light is longer than the major axis of the first light.

2. the first light shaping unit and the second light shaping unit are configured to receive the laser light from a common laser light source; 2. The foreign matter inspection device according to claim 1, wherein the light switching mechanism switches between a state in which the laser light from the laser light source is introduced into the first light shaping unit and a state in which the laser light from the laser light source is introduced into the second light shaping unit when foreign matter inspection of the measurement object is completed and foreign matter inspection of the next measurement object is started.

3. the light irradiation unit further includes a light scanning unit that scans the measurement object with the first light from the first light shaping unit and the second light from the second light shaping unit in a direction intersecting the movement direction, The optical switching mechanism includes: an incident side mirror provided between the laser light source and the first light shaping unit or the second light shaping unit; an exit-side mirror provided between the first light shaping unit or the second light shaping unit and the light scanning unit; 3. The foreign body inspection device according to claim 1, further comprising a switching actuator that switches between a first optical path, which is an optical path from the laser light source to the optical scanning unit via the first light shaping unit, and a second optical path, which is an optical path from the laser light source to the optical scanning unit via the second light shaping unit, by moving the incident side mirror and the exit side mirror.

4. the first light shaping unit and the light scanning unit are provided on an optical path of the laser light emitted from the laser light source, the incident-side mirror reflects the laser light from the laser light source toward the second light shaping unit, and the exit-side mirror reflects the second light from the second light shaping unit toward the light scanning unit, 4. The foreign body inspection device according to claim 3, wherein the switching actuator retracts the incident side mirror and the exit side mirror from an optical path of the laser light emitted from the laser light source to form the first optical path, and positions the incident side mirror and the exit side mirror on the optical path of the laser light emitted from the laser light source to form the second optical path.

5. 5. The foreign substance inspection device according to claim 1, wherein the second light shaping unit shapes the second light by guiding the laser light from a laser light source to a plurality of optical members.

6. 6. The foreign body inspection device according to claim 1, wherein the second light shaping unit shapes the second light by expanding the laser light from the laser light source in an entire circumferential direction and then expanding the laser light in one direction.

7. 7. The foreign body inspection device according to claim 6, wherein the second light shaping unit shapes the second light by guiding the laser light from the laser light source to a magnifying lens and then to an optical element including at least a cylindrical lens.

8. 8. The foreign body inspection device according to claim 1, wherein a feed pitch in the movement direction of the measurement object irradiated with the second light is larger than a feed pitch in the movement direction of the measurement object irradiated with the first light.

9. A foreign body inspection method comprising: irradiating a measurement object that is moving relatively along a predetermined movement direction with light; detecting the light from the measurement object when the light is irradiated onto the measurement object; and detecting foreign bodies in the measurement object based on the light detected from the measurement object, When the foreign substance inspection of the measurement object is completed and the foreign substance inspection of the next measurement object is started, the light to be emitted to the measurement object can be switched to a first light or a second light which is different from the first light, a major axis of the first light and a major axis of the second light are aligned along the movement direction in an irradiation shape on the measurement object, and the major axis of the second light is longer than the major axis of the first light.

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