Optical inspection device, defect inspection device, and method for manufacturing a substrate

Abstract

In the present invention, an optical device control unit (80) outputs, to a stage movement unit (12), a control signal (for example, a control signal for autofocus control) for controlling the positional relationship between the position of a substrate (WF) and the condensing position of first irradiation light (La) in the optical axis direction of an objective optical system (15), on the basis of substrate configuration information relating to the configuration of the substrate (WF), a second light reception signal output from a second detector of a surface detection unit (55), and setting information on the condensing position of the first irradiation light (La).

Description

[Technical Field]

[0001] The present invention relates to an optical inspection device, a defect inspection device, and a method for manufacturing a substrate. [Background technology]

[0002] Some substrate inspection devices irradiate the substrate surface with laser light and detect the reflected or scattered light to inspect for defects on the substrate surface (see, for example, Patent Document 1). In substrate defect inspection, there is a growing need to inspect not only defects on the surface of the substrate, but also defects inside the substrate. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] U.S. Patent No. 6798504 [Overview of the project]

[0004] A first inspection optical device according to the present invention is an inspection optical device used in a defect inspection device for inspecting defects in a substrate, comprising: a first irradiation optical system that irradiates a first irradiation light toward the substrate via an objective optical system; a first light receiving unit that receives light generated inside the substrate by the first irradiation light irradiated onto the substrate via the objective optical system and outputs a first light receiving signal; a processing unit that generates information about the inside of the substrate based on the first light receiving signal from the first light receiving unit; a second irradiation optical system that irradiates a second irradiation light toward the substrate via the objective optical system; a second light receiving unit that receives reflected light from the surface of the substrate irradiated with the second irradiation light and outputs a second light receiving signal; and a control unit that outputs a control signal to a moving unit that moves at least one of the focusing position of the first irradiation light and the position of the substrate in the optical axis direction, based on substrate configuration information relating to the configuration of the substrate and the second light receiving signal.

[0005] A second inspection optical device according to the present invention is an inspection optical device used in a defect inspection device for inspecting defects in a substrate, comprising: an illumination optical system that irradiates the substrate with illumination light from a light source via an objective optical system; a light receiving unit that receives light generated inside the substrate by the illumination light irradiated onto the substrate via the objective optical system and outputs a light receiving signal; a processing unit that generates information about the inside of the substrate based on the light receiving signal from the light receiving unit; and a control unit that controls the light source to irradiate the substrate with illumination light when the focusing position of the illumination light in the optical axis direction of the objective optical system is inside the substrate.

[0006] A third inspection optical device according to the present invention is an inspection optical device used in a defect inspection device for inspecting defects in a substrate, comprising: an illumination optical system that irradiates the substrate with illumination light from a light source via an objective optical system; a light receiving unit that receives light generated inside the substrate by the illumination light irradiated onto the substrate via the objective optical system and outputs a light receiving signal; a processing unit that generates information about the inside of the substrate based on the light receiving signal from the light receiving unit; and a control unit that controls the light source to restrict the irradiation of the illumination light toward the substrate when the focusing position of the illumination light in the optical axis direction of the objective optical system is not inside the substrate.

[0007] A fourth inspection optical device according to the present invention is an inspection optical device used in a defect inspection device for inspecting defects in a substrate, comprising: an illumination optical system that irradiates illumination light toward the substrate via an objective optical system; a light receiving unit that receives light generated inside the substrate by the illumination light irradiated onto the substrate via the objective optical system and outputs a light receiving signal; and a processing unit that generates information about the inside of the substrate based on substrate topography information relating to the topography of the substrate and the light receiving signal from the light receiving unit.

[0008] A fifth inspection optical device according to the present invention is an inspection optical device used in a defect inspection device for inspecting defects in a substrate, comprising: an illumination optical system that irradiates a first illumination light toward the substrate via an objective optical system; a light receiving unit that receives light generated inside the substrate by the first illumination light irradiated onto the substrate via the objective optical system and outputs a light receiving signal; a processing unit that generates information about the inside of the substrate based on the light receiving signal from the light receiving unit; a substrate surface position detection unit that irradiates a second illumination light onto the surface of the substrate and receives the second illumination light reflected from the surface of the substrate to detect the position of the surface of the substrate in the optical axis direction of the objective optical system or in a direction parallel to the optical axis direction; and a control unit that outputs a control signal to a moving unit that moves at least one of the focusing position of the first illumination light and the position of the substrate in the optical axis direction to control the positional relationship between the focusing position of the first illumination light and the position of the substrate in the optical axis direction, wherein the inspection optical device irradiates a first region, which is a part of the substrate, with the first illumination light, and the substrate The first irradiation light irradiated onto the first region of the plate causes light generated inside the substrate to be received by the light receiving unit, and internal information in the first region is generated as first information. The first irradiation light is irradiated onto a second region of the substrate that is different from the first region, and light generated inside the substrate to be received by the light receiving unit when the first irradiation light irradiated onto the second region of the substrate is received by the light receiving unit, and internal information in the second region is generated as second information. The substrate surface position detection unit irradiates the surface of the second region of the substrate with second irradiation light during the first period in which the first irradiation light is irradiated onto the first region, and receives the second irradiation light reflected from the surface of the second region to detect the position of the surface of the second region in the optical axis direction of the objective optical system or in a direction parallel to the optical axis direction. The control unit generates a control signal that controls the positional relationship between the focusing position of the first irradiation light in the optical axis direction and the position of the substrate during the second period in which the first irradiation light is irradiated onto the second region, based on the detection result of the position of the surface of the second region.

[0009] The sixth inspection optical device according to the present invention is an inspection optical device used in a defect inspection device for inspecting defects in a substrate having a plurality of layers stacked in the thickness direction, and comprises: an irradiation optical system that irradiates a first irradiation light toward the substrate via an objective optical system; a light receiving unit that receives light generated inside at least one of the plurality of layers of the substrate by the first irradiation light irradiated toward the substrate via the objective optical system and outputs a light receiving signal; a substrate interface position detection unit that irradiates a second irradiation light toward at least one interface among the interfaces of the plurality of layers of the substrate and receives the second irradiation light reflected from the interface to detect the position of the interface of the substrate in the optical axis direction of the objective optical system or in a direction parallel to the optical axis direction; and a processing unit that generates information about the interior of the at least one layer of the substrate based on position information regarding the position of the interface of the substrate and the light receiving signal from the light receiving unit.

[0010] The defect inspection apparatus according to the present invention is a defect inspection apparatus for inspecting defects in a substrate, comprising the above-described inspection optical apparatus, and inspecting defects in the substrate based on the information of the inside of the substrate generated by the inspection optical apparatus.

[0011] The method for manufacturing a substrate according to the present invention includes creating a substrate and inspecting the created substrate using the defect inspection apparatus described above. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram showing a defect inspection apparatus according to the first embodiment. [Figure 2] This is a cross-sectional view showing an example of a substrate. [Figure 3] This is a schematic diagram showing the first detector. [Figure 4] This is a schematic diagram showing a surface detection unit according to the first embodiment. [Figure 5] This is a schematic diagram showing the state in which the image formation position of the slit aperture of the second illumination coincides with the focal position of the objective optical system. [Figure 6]It is a schematic diagram showing a state where the imaging position of the image of the slit aperture of the second irradiation light is separated from the focal position of the objective optical system. [Figure 7] It is a schematic diagram showing a state where the imaging position of the image of the slit aperture of the second irradiation light is located on the surface of the substrate. [Figure 8] It is a schematic diagram showing a case where the condensing position of the first irradiation light is set inside the second layer on the substrate in the first embodiment. [Figure 9] It is a schematic diagram showing a case where the condensing position of the first irradiation light is set inside the third layer on the substrate in the first embodiment. [Figure 10] It is a schematic diagram showing a surface detection deflection unit and a surface detection unit according to the second embodiment. [Figure 11] It is a schematic diagram showing a case where the surface detection deflection mirror of the surface detection deflection unit rotates and moves to the second rotation position. [Figure 12] It is a schematic diagram showing a modified example of the surface detection deflection unit. [Figure 13] It is a schematic configuration diagram showing a defect inspection apparatus according to the third embodiment. [Figure 14] It is a schematic configuration diagram showing a surface detection unit according to the third embodiment. [Figure 15] It is a schematic diagram showing a case where the condensing position of the first irradiation light is set inside the second layer on the substrate in the third embodiment. [Figure 16] It is a schematic configuration diagram showing a defect inspection apparatus according to the fourth embodiment. [Figure 17] It is a schematic configuration diagram showing a surface detection unit according to the fourth embodiment. [Figure 18] It is a schematic diagram showing a case where the condensing position of the first irradiation light is set inside the second layer on the substrate in the fourth embodiment. [Figure 19] It is a graph showing an example of the signal voltage of the second received light signal. [Figure 20] It is a flowchart showing a method for manufacturing a substrate.

Embodiments for Carrying Out the Invention

[0013] The embodiments will be described below. In the following description, the directions indicated by the arrows in Figure 1 may be referred to as the X direction, Y direction, and Z direction, respectively. The X direction, Y direction, and Z direction are mutually orthogonal directions. The Z direction is parallel to the optical axis AX of the objective optical system 15. Furthermore, the coordinate position in the X direction may be referred to as the X position, the coordinate position in the Y direction as the Y position, and the coordinate position in the Z direction as the Z position.

[0014] [First Embodiment] First, a defect inspection apparatus 1 according to the first embodiment will be described. As shown in Figure 1, the defect inspection apparatus 1 according to the first embodiment comprises an inspection optical device 10 and an information processing device 90. The inspection optical device 10 and the information processing device 90 are configured to send and receive data from each other via a network cable NW. The inspection optical device 10 is also called a scanning microscope. The inspection optical device 10 comprises a stage 11 on which a substrate WF is placed, an objective optical system 15, a first light source unit 20, a first irradiation optical system 30, a first light receiving unit 40, a surface detection unit 55, and an optical device control unit 80.

[0015] Stage 11 supports the substrate WF, which is the object to be inspected. The substrate WF is formed in a plate shape having multiple layers (for example, five layers) stacked in the thickness direction, as shown in Figure 2 as an example. In the example shown in Figure 2, the substrate WF has, in order from the surface side of the substrate WF, a first layer LY1, a second layer LY2, a third layer LY3, a fourth layer LY4, and a fifth layer LY5. For example, AlGaN (aluminum gallium nitride) is used as the material for the first layer LY1. For example, GaN (gallium nitride) is used as the material for the second layer LY2. For example, C-GaN is used as the material for the third layer LY3. The fourth layer LY4 is a buffer layer. The fifth layer LY5 is the base substrate layer. For example, Si (silicon) is used as the material for the fifth layer LY5 (base substrate). Such a substrate WF may be a substrate used in the manufacture of power devices (power semiconductors) such as high electron mobility transistors (HEMTs). Furthermore, the materials for the first layer LY1 to the fourth layer LY4 are not limited to the materials described above, but may be other materials. Also, the number of layers in the substrate WF is not limited to five layers, but may be less than five layers or more than five layers. The material of the fifth layer LY5 (base substrate) is not limited to Si, but may be SiC, GaN, or sapphire. Hereafter, a substrate in which at least one layer is formed using GaN may be referred to as a GaN substrate.

[0016] A stage movement unit 12 is provided on the stage 11. The stage movement unit 12 moves the stage 11 in directions perpendicular to the optical axis AX (Z direction) of the objective optical system 15, i.e., in the X and Y directions. By moving the stage 11 in the X and Y directions (directions perpendicular to the optical axis AX of the objective optical system 15) using the stage movement unit 12, the observation area of ​​the substrate WF facing the objective optical system 15 can be displaced in the X and Y directions (directions along the cross-section of the substrate WF). The observation area is defined as a portion of the substrate WF scanned by the deflection unit 32 described later via the objective optical system 15. The observation area may be set to a range narrower than the actual field of view of the inspection optical device 10, or it may be set to the same range as the actual field of view of the inspection optical device 10.

[0017] Furthermore, the stage movement unit 12 can move the stage 11 in the direction along the optical axis AX of the objective optical system 15, i.e., in the Z direction. When the stage 11 is moved in the Z direction by the stage movement unit 12, the relative position of the objective optical system 15 with respect to the substrate WF supported by the stage 11 changes in the Z direction, and the focal position of the objective optical system 15 changes in the Z direction inside the substrate WF. By changing the focal position of the objective optical system 15 in the Z direction inside the substrate WF, it is possible to acquire images of multiple cross-sections inside the substrate WF with different Z positions (positions along the optical axis AX of the objective optical system 15). Hereafter, the direction along the optical axis AX of the objective optical system 15 may be referred to as the optical axis direction of the objective optical system 15. Also, images of multiple cross-sections with different Z positions inside the substrate WF may be referred to as Z-stacked images inside the substrate WF.

[0018] The objective optical system 15 is positioned above the stage 11. The objective optical system 15 faces the substrate WF supported by the stage 11. The objective optical system 15 is composed of multiple lenses 16 and is housed in a lens housing 17. In Figure 1, the objective optical system 15 is composed of four lenses 16 as an example, but is not limited to this. For example, the objective optical system 15 may be composed of five or more lenses, or of two or three lenses. Furthermore, at least some of the multiple lenses 16 may be configured to be movable in the optical axis direction of the objective optical system 15 by rotating a correction ring (not shown) provided on the lens housing 17. In addition to moving the stage 11 in the Z direction by the stage moving unit 12, or in addition to moving the stage 11 in the Z direction by the stage moving unit 12, the objective optical system 15 may be moved in the Z direction (optical axis direction) to change the focal position of the objective optical system 15 in the Z direction inside the substrate WF.

[0019] The first light source unit 20 emits first irradiation light La toward the first irradiation optical system 30. The first light source unit 20 comprises a first light source 21 and a light source lens 22. As the first light source 21, for example, a laser light source capable of emitting laser light in a predetermined wavelength range is used. The laser light emitted from the first light source 21 is shaped by the light source lens 22 to become parallel light and emitted from the first light source unit 20 as first irradiation light La. The first light source 21 may be a laser light source that emits pulsed light having a pulse width of less than 1 picosecond (for example, a pulse width in femtosecond units) (for example, a laser light source that emits a femtosecond laser). The first light source 21 is not limited to a laser light source that emits pulsed light, but may also be a laser light source that emits continuous oscillation light. Furthermore, the first light source 21 is not limited to a laser light source, but may be configured using an LED (Light Emitting Diode) or an emission line lamp.

[0020] The wavelength of the first irradiation light La is selected within a wavelength range (for example, the wavelength range of 700 nm to 1030 nm) that can cause the material constituting the substrate WF to emit light through multiphoton excitation. For example, the wavelength of the first irradiation light La may be selected within a wavelength that can cause the material constituting the substrate WF to emit light through two-photon excitation. If the substrate WF is a GaN substrate, the wavelength of the first irradiation light La may be selected at 700 nm or at 1030 nm. Regarding the two-photon excitation of GaN with laser light having a wavelength of 700 nm, this is disclosed in the paper "Tomoyuki Tanikawa et al., Three-dimensional imaging of threading dislocations in GaN crystals using two-photon excitation photoluminescence, Applied Physics Express, 11, 031004 (2018)". Regarding the multiphoton excitation of GaN with laser light having a wavelength of 1030 nm, this is disclosed in the paper "Mayuko Tsukakoshi et al., Identification of Burgers vectors of threading dislocations in freestanding GaN substrates via multiphoton-excitation photoluminescence mapping, Applied Physics Express, 14, 055504 (2021)".

[0021] The first illumination optical system 30 irradiates the first illumination light La emitted from the first light source unit 20 toward the substrate WF via the objective optical system 15. By moving the stage 11 in the Z direction using the stage moving unit 12, the relative position of the objective optical system 15 with respect to the substrate WF supported by the stage 11 is adjusted so that the first illumination light La emitted from the objective optical system 15 is focused inside the substrate WF. Hereafter, the region inside the substrate WF in which the first illumination light La is focused to a size approximately equal to the resolution limit of the objective optical system 15 may be referred to as the illumination region 25. The size of the illumination region 25 is, for example, the beam width of the first illumination light La, which is laser light (for example, 1 / e2 The resolution limit of the objective optical system 15 corresponds to the radius of the first dark ring of the so-called Airy disk. When the wavelength of the first irradiated light La is λ1 and the numerical aperture of the objective optical system 15 (the sine of the opening angle of the first irradiated light La emitted from the objective optical system 15) is NA, the resolution limit is calculated as 0.61 × λ1 / NA. When the size of the illumination area 25 is smaller than the diameter of the first dark ring of the Airy disk, which is 1.22 × λ1 / NA, the first irradiated light La is said to be focused to the resolution limit.

[0022] The first illumination optical system 30 comprises, in order from the first light source unit 20 side, a first dichroic mirror 31, a deflection unit 32, a first relay lens 33, a second relay lens 34, and a second dichroic mirror 35. The first dichroic mirror 31 has the characteristic of reflecting blue light or light in the wavelength range shorter than blue light, and transmitting light in the wavelength range longer than blue light. The first dichroic mirror 31 is not limited to the wavelength characteristics described above, and only has the characteristic of reflecting light generated inside the substrate WF by multiphoton excitation and transmitting the first illumination light La emitted from the first light source unit 20. Hereafter, the light generated inside the substrate WF by multiphoton excitation may be referred to as detection light Ld.

[0023] The deflection unit 32 scans the inside of the substrate WF with the first irradiation light La from the first light source unit 20 in two directions, the X direction and the Y direction. The deflection unit 32 is equipped with an X-direction deflection mirror 32a and a Y-direction deflection mirror 32b that can change the direction of propagation of the first irradiation light La. The X-direction deflection mirror 32a and the Y-direction deflection mirror 32b are constructed using galvanometer mirrors, MEMS mirrors, resonant mirrors (resonant mirrors), etc. The X-direction deflection mirror 32a and the Y-direction deflection mirror 32b are positioned at a location that is the conjugate plane of the pupil plane Pp of the objective optical system 15, or in the vicinity of a location that is the conjugate plane of the pupil plane Pp of the objective optical system 15. When the X-direction deflection mirror 32a swings or rotates in the rotational direction (θy direction) about the Y axis, the direction of propagation of the first irradiation light La changes in the θy direction about the Y axis, and the irradiation area 25 in the substrate WF moves in the X direction. As the Y-direction deflection mirror 32b swings or rotates around the X-axis in the rotational direction (θx direction), the direction of propagation of the first irradiation light La changes in the θx direction around the X-axis, causing the irradiation area 25 on the substrate WF to move in the Y direction. Therefore, the deflection unit 32 can move the irradiation area 25 on the substrate WF in two directions (X and Y directions) by swinging or rotating the X-direction deflection mirror 32a and the Y-direction deflection mirror 32b, and scan the inside of the substrate WF in two dimensions.

[0024] A first intermediate image plane Im1, conjugate to the substrate WF (object plane), is formed between the first relay lens 33 and the second relay lens 34. The first relay lens 33 focuses the first illumination light La from the deflection unit 32 onto the first intermediate image plane Im1. The first intermediate image plane Im1 may also be called the first conjugate plane Im1. The second relay lens 34 guides the first illumination light La from the first relay lens 33 into the objective optical system 15 (second dichroic mirror 35) as parallel light. The second relay lens 34 also focuses the detection light Ld from the objective optical system 15 (second dichroic mirror 35) onto the first intermediate image plane Im1. The first relay lens 33 guides the detection light Ld from the second relay lens 34 into the deflection unit 32 as parallel light. Note that the first relay lens 33 and the second relay lens 34 are not limited to one lens, but may be composed of multiple lenses. The first relay lens 33 is also called a scan lens. The second relay lens 34 is also called an imaging lens or a second objective lens.

[0025] The second dichroic mirror 35 has the characteristic of reflecting light in the green light wavelength range and transmitting light in the longer wavelength range and light in the shorter wavelength range than green light. The second dichroic mirror 35 is not limited to the wavelength characteristics described above, and it is sufficient if it has the characteristic of reflecting the second illumination light Lb (and the reflected light Le described later) from the surface detection unit 55 and transmitting the first illumination light La from the second relay lens 34 and the detection light Ld from the objective optical system 15.

[0026] The first light-receiving unit 40 comprises a first light-receiving optical system 41 and a first detector 51. The first light-receiving optical system 41 receives detection light Ld generated inside the substrate WF (irradiation region 25) by multiphoton excitation by the first irradiation light La via the objective optical system 15, and forms an image 49 of the irradiation region 25 inside the substrate WF on the image plane Imp. The first light-receiving optical system 41 includes the second dichroic mirror 35, second relay lens 34, first relay lens 33, deflection unit 32, and first dichroic mirror 31 of the first irradiation optical system 30. Furthermore, the first light-receiving optical system 41 comprises, in order from the first dichroic mirror 31 side (substrate WF side), a barrier filter 42, a focusing lens 43, and a magnification optical system 45.

[0027] The barrier filter 42 has the characteristic of transmitting light in a predetermined wavelength range (specifically, detection light Ld) from the first dichroic mirror 31. The barrier filter 42 blocks at least a portion of the first illumination light La reflected by the substrate WF, ambient light, stray light, etc. The barrier filter 42 is also called a bandpass filter. A second intermediate image plane Im2, conjugate to the substrate WF (object plane), is formed between the focusing lens 43 and the magnification optical system 45. The focusing lens 43 focuses the detection light Ld that has passed through the barrier filter 42 onto the second intermediate image plane Im2. The second intermediate image plane Im2 may also be called the second conjugate plane Im2. The focusing lens 43 is not limited to one lens, but may be composed of multiple lenses.

[0028] The variable magnification optical system 45 focuses the detected light Ld from the condensing lens 43 onto the image plane Imp, forming an image 49 of the illuminated area 25 inside the substrate WF. The substrate WF (object plane), the first intermediate image plane Im1, the second intermediate image plane Im2, and the image plane Imp are conjugate planes to each other. The variable magnification optical system 45 is composed of multiple lenses 46 and is held in a zoom lens barrel 48, which has cam grooves formed on it, via a retaining frame 47. By rotating the zoom lens barrel 48 with an electric motor (not shown), at least some of the multiple lenses 46 move (in the direction of the optical axis of the variable magnification optical system 45), changing the focal length and principal point position of the variable magnification optical system 45. As a result, the imaging magnification of the variable magnification optical system 45 (i.e., the imaging magnification of the first light-receiving optical system 41) changes, and the size of the image 49 formed on the image plane Imp changes.

[0029] In Figure 1, the variable magnification optical system 45 is configured using four lenses 46 as an example, but it is not limited to this. For example, the variable magnification optical system 45 may be configured using five or more lenses, or it may be configured using two or three lenses. Alternatively, the first detector 51 may be placed on the second intermediate image plane Im2 without providing the variable magnification optical system 45.

[0030] The first detector 51 is configured, for example, using an avalanche photodiode array. The first detector 51 has a detection surface 52 having a plurality of detection pixels 53 arranged in a two-dimensional direction (see Figure 3). For example, the detection surface 52 may have 25 detection pixels 53 arranged in a vertical and horizontal direction of 5 each. The first detector 51 is positioned so that the detection surface 52 overlaps with the image plane Imp. As a result, the detection light Ld from the magnification optical system 45 is focused onto the detection surface 52 of the first detector 51, forming an image 49 of the illuminated area 25 inside the substrate WF. The first detector 51 receives the image 49 of the illuminated area 25 inside the substrate WF formed on the detection surface 52, performs photoelectric conversion, and outputs a received signal (also called a detection signal) of the image 49 of the illuminated area 25 inside the substrate WF. At this time, the first detector 51 receives an image 49 of the illuminated area 25 inside the substrate WF using multiple detection pixels 53, performs photoelectric conversion, and outputs a light-receiving signal corresponding to the light intensity of the image 49 of the illuminated area 25 inside the substrate WF. Hereafter, the light-receiving signal output from the first detector 51 may be referred to as the first light-receiving signal. Note that an NDD (Non-descanned) type detector may be used as the first detector 51.

[0031] As shown in Figure 4, the surface detection unit 55 comprises a second light source 60, a second irradiation optical system 61, and a second light receiving unit 70. Furthermore, the surface detection unit 55 includes a second dichroic mirror 35 of the first irradiation optical system 30. The second light source 60 emits a second irradiation light Lb toward the second irradiation optical system 61. The second light source 60 is configured using, for example, an LED. However, the second light source 60 is not limited to an LED and may be configured using a laser light source. The wavelength of the second irradiation light Lb is selected to be within the wavelength range that can be reflected by the second dichroic mirror 35 (for example, the wavelength range of green light). Alternatively, the wavelength of the second irradiation light Lb may be selected to be within the wavelength range that can be reflected by the surface of the substrate WF, or within the wavelength range that can be reflected by the interfaces of multiple layers of the substrate WF (from the first layer LY1 to the fifth layer LY5).

[0032] The second illumination optical system 61 irradiates the surface of the substrate WF with the second illumination light Lb emitted from the second light source 60 via the objective optical system 15. At this time, the second illumination optical system 61 irradiates the surface of the substrate WF with the second illumination light Lb from a direction inclined with respect to the optical axis AX of the objective optical system 15. The second illumination optical system 61 comprises, in order from the second light source 60 side, a first collector lens 62, a slit plate 63, a second collector lens 64, a first pupil limiting mask 65, a half mirror 66, a focal position adjustment lens 67, and a bandpass filter 68.

[0033] The first collector lens 62 focuses the second irradiation light Lb emitted from the second light source 60. The slit plate 63 is positioned conjugate to the substrate WF (object surface). A slit opening 63a is formed in the center of the slit plate 63. The slit opening 63a is formed in a rectangular shape with its longitudinal direction extending in the Y direction (a direction perpendicular to the optical axis direction of the second irradiation optical system 61). The second irradiation light Lb passing through the slit opening 63a becomes rectangular in cross-sectional view. The second collector lens 64 guides the second irradiation light Lb that has passed through the slit opening 63a to the first pupil limiting mask 65.

[0034] The first pupil limiting mask 65 is positioned at the pupil in the second illumination optical system 61 and blocks half of the pupil. The first pupil limiting mask 65 is also positioned to block half of the region bounded by the longitudinal center line of the rectangular cross-section of the second illumination light Lb. The half mirror 66 transmits a portion of the second illumination light Lb that has passed through the first pupil limiting mask 65. The half mirror 66 also reflects a portion of the second illumination light Lb that has been reflected from the surface of the substrate WF and passed through the focal position adjustment lens 67 toward the second objective lens 72 for receiving light in the second light receiving unit 70 (second light receiving optical system 71). The ratio of transmittance to reflectance of the half mirror 66 is set to, for example, 1:1. Hereafter, the second illumination light Lb reflected from the surface of the substrate WF may be referred to as reflected light Le.

[0035] The focal position adjustment lens 67 has a convex lens 67a and a concave lens 67b. One of the convex lens 67a and the concave lens 67b is fixed on the optical axis, and the other is configured to be movable along the optical axis. Alternatively, both the convex lens 67a and the concave lens 67b may be configured to be movable along the optical axis. In the following description, we will describe the case in which the convex lens 67a is fixed on the optical axis and the concave lens 67b is configured to be movable along the optical axis. The focal position adjustment lens 67 is provided with a lens movement unit 69. The lens movement unit 69 is configured to have a focal position adjustment lens motor (not shown) capable of driving the concave lens 67b of the focal position adjustment lens 67. The lens movement unit 69 moves the concave lens 67b of the focal position adjustment lens 67 along the optical axis. Note that the convex lens 67a may be a lens group composed of multiple lenses that have positive power as a whole, and the concave lens 67b may be a lens group composed of multiple lenses that have negative power as a whole. In this case, the lens moving unit 69 may move one or more of these lens groups along the optical axis.

[0036] Furthermore, if multiple types of focus position adjustment lenses 67 with different magnifications are provided, the lens movement unit 69 may have an electric turret (not shown) for the focus position adjustment lenses. In this case, the electric turret for the focus position adjustment lenses of the lens movement unit 69 selects one of the multiple types of focus position adjustment lenses 67 and places it on the optical path between the half mirror 66 and the bandpass filter 68 in response to the operation of a focus position switching operation switch (not shown) provided, for example, in the inspection optical device 10 or the information processing device 90.

[0037] The bandpass filter 68 is positioned in the optical path between the focus adjustment lens 67 and the second dichroic mirror 35. The bandpass filter 68 has the property of transmitting light in the wavelength range of green light (specifically, the second illumination light Lb and reflected light Le). The bandpass filter 68 blocks at least some of the detection light Ld reflected by the second dichroic mirror 35, ambient light, stray light, etc.

[0038] The second light-receiving unit 70 comprises a second light-receiving optical system 71 and a second detector 78. The second light-receiving optical system 71 receives reflected light Le from the surface of the substrate WF irradiated with the second irradiation light Lb via the objective optical system 15 and focuses it on the second detector 78. The second light-receiving optical system 71 includes a bandpass filter 68, a focal position adjustment lens 67, and a half mirror 66 of the second irradiation optical system 61. Furthermore, the second light-receiving optical system 71 comprises, in order from the half mirror 66 side (substrate WF side), a second objective lens 72 for receiving light, a first relay lens 73 for receiving light, a second pupil limiting mask 74, a second relay lens 75 for receiving light, and a cylindrical lens 76.

[0039] The second light-receiving objective lens 72 focuses the reflected light Le reflected by the half-mirror 66. The first light-receiving relay lens 73 guides the reflected light Le from the second light-receiving objective lens 72 to the second pupil limiting mask 74. The second pupil limiting mask 74 is positioned at the pupil in the second light-receiving optical system 71 and is designed to block half of the pupil. The area blocked by the second pupil limiting mask 74 corresponds to the area blocked by the first pupil limiting mask 65. As a result, the reflected light Le from the first light-receiving relay lens 73 can pass through the second pupil limiting mask 74. The second light-receiving relay lens 75 focuses the reflected light Le that has passed through the second pupil limiting mask 74 toward the detection surface 79 of the second detector 78. The cylindrical lens 76 compresses the reflected light Le, which is focused by the second light-receiving relay lens 75, in the longitudinal direction (Y direction) of its rectangular cross-section, and forms an image of the slit aperture 63a on the detection surface 79 of the second detector 78.

[0040] The second detector 78 is configured, for example, using a line sensor. The second detector 78 has a detection surface 79 having a plurality of detection pixels (not shown) arranged in a one-dimensional direction (for example, the X direction, which is the short-side direction of the image of the slit aperture 63a). Reflected light Le from the second photo-receiving optical system 71 (second irradiation light Lb reflected from the surface of the substrate WF) is focused on the detection surface 79 of the second detector 78 to form an image of the slit aperture 63a. The second detector 78 receives the image of the slit aperture 63a formed on the detection surface 79, performs photoelectric conversion, and outputs a received signal (also called a detection signal) of the image of the slit aperture 63a. The second detector 78 may also be configured using a two-dimensional image sensor. Hereafter, the received signal output from the second detector 78 may be referred to as the second received signal.

[0041] The optical device control unit 80 is configured using, for example, a CPU (Central Processing Unit). The optical device control unit 80 includes an interface unit 81, a storage unit 85, a data acquisition unit 86, an image processing unit 87, and a calculation unit 88. Based on a control program stored in the storage unit 85, the optical device control unit 80 controls the operation of the stage moving unit 12, the first light source unit 20 (first light source 21), the deflection unit 32, the electric motor (not shown) of the magnification optical system 45, the surface detection unit 55 (second light source 60, lens moving unit 69), etc.

[0042] The interface unit 81 is electrically connected to one end of the network cable NW. The other end of the network cable NW is electrically connected to the interface unit 91 of the information processing device 90. The interface unit 81 of the optical device control unit 80 receives information transmitted from the interface unit 91 of the information processing device 90 via the network cable NW regarding the setting position of the first irradiation light La and the configuration of the substrate WF. The information regarding the setting position of the first irradiation light La and the configuration of the substrate WF, which is input to the interface unit 81, is stored in the storage unit 85. Hereafter, the information regarding the configuration of the substrate WF will be referred to as substrate configuration information.

[0043] The focusing position of the first irradiation light La is offset in the Z direction (along the optical axis direction of the objective optical system 15) relative to the surface of the substrate WF. The setting information for the focusing position of the first irradiation light La is set according to the Z position of the cross-sectional area to be inspected inside the substrate WF. In addition, the focusing position of the first irradiation light La may be set inside any of the multiple layers in the substrate WF. In the example shown in Figure 2, the focusing position of the first irradiation light La may be set inside the second layer LY2 formed using GaN, for example, or inside the third layer LY3 formed using C-GaN, for example.

[0044] The substrate configuration information includes information on multiple layers in the substrate WF. For example, the substrate configuration information may include information on the layer thickness in the thickness direction of multiple layers in the substrate WF and the refractive index of those multiple layers. In the example shown in Figure 2, the substrate configuration information may include information on the layer thickness and refractive index of the first layer LY1 in the substrate WF, information on the layer thickness and refractive index of the second layer LY2, information on the layer thickness and refractive index of the third layer LY3, information on the layer thickness and refractive index of the fourth layer LY4, and information on the layer thickness and refractive index of the fifth layer LY5. The refractive index of the multiple layers in the substrate WF is the refractive index with respect to the wavelength of the first irradiated light La. If the first irradiated light La is light with a wavelength width, the refractive index of the multiple layers in the substrate WF may be the refractive index with respect to the center wavelength of the first irradiated light La. In this case, the refractive index of the multiple layers in the substrate WF may also be the refractive index with respect to one or more wavelengths within the wavelength width of the first irradiated light La. The substrate configuration information may also include information on some of the multiple layers in the substrate WF. For example, if there are five layers and only the top layer is inspected for internal defects, the information regarding the refractive index of the top layer can be used as substrate configuration information. Also, for example, if there are five layers and only the top layer and the two layers below it are inspected for internal defects, the information regarding the thickness and refractive index of the top layer, as well as the refractive index of the layer below it, can be used as substrate configuration information.

[0045] Furthermore, the memory unit 85 may store information regarding the aperture angle of the first illumination light La directed from the objective optical system 15 toward the substrate WF. In this embodiment, the aperture angle of the first illumination light La is the maximum angle of the first illumination light La focused by the objective optical system 15 with respect to the optical axis AX of the objective optical system 15. The information regarding the aperture angle of the first illumination light La may also be referred to as information regarding the illumination numerical aperture of the first illumination light La. The information regarding the aperture angle of the first illumination light La may be information regarding the sine of the aperture angle of the first illumination light La, or it may be information regarding the numerical aperture of the objective optical system 15.

[0046] The data acquisition unit 86 acquires the first light-receiving signal output from the first detector 51. The optical device control unit 80 causes the data acquisition unit 86 to acquire the first light-receiving signal in synchronization with scanning inside the substrate WF by moving the illumination area 25 in two directions (X and Y directions) using the deflection unit 32. The image processing unit 87 generates image data of the cross-section of the substrate WF in the XY direction (direction perpendicular to the thickness direction of the substrate WF) inside the substrate WF based on the first light-receiving signal output from multiple detection pixels 53 of the first detector 51 acquired by the data acquisition unit 86. The image processing unit 87 may also generate intermediate image data of the cross-section of the substrate WF for each detection pixel 53 of the multiple detection pixels 53 of the first detector 51 that output the first light-receiving signal. Furthermore, as disclosed in, for example, International Publication No. 2022 / 102584, the image processing unit 87 may generate image data of the cross-section of the substrate WF by position-shifting and adding multiple intermediate image data generated for each detected pixel 53 according to the position of the corresponding detected pixel 53 within the detection surface 52 (image plane Imp).

[0047] Furthermore, the data acquisition unit 86 acquires the second light-receiving signal output from the second detector 78. The optical device control unit 80 performs autofocus control, which will be described later, based on the second light-receiving signal output from the second detector 78 acquired by the data acquisition unit 86. The calculation unit 88 determines the control signal to be output to the stage movement unit 12 in autofocus control.

[0048] The information processing device 90 is configured using, for example, a PC (Personal Computer). The information processing device 90 comprises an interface unit 91, an input unit 92, a display unit 93, an input / output control unit 94, a storage unit 95, and a determination unit 96. The interface unit 91 is electrically connected to the other end of a network cable NW. Image data of the inside of the substrate WF, transmitted from the interface unit 81 of the inspection optical device 10 (optical device control unit 80) via the network cable NW, is input to the interface unit 91 of the information processing device 90. The image data of the inside of the substrate WF input to the interface unit 91 is stored in the storage unit 95.

[0049] The input unit 92 is an input interface that can be operated by the user. The input unit 92 is configured using at least one of the following: a mouse, keyboard, touchpad, trackball, etc. The input unit 92 detects user operation and outputs the detection result to the input / output control unit 94 as user-inputted input information. The input unit 92 may be input with the setting information of the focusing position of the first irradiation light La described above, or it may be input with the substrate configuration information described above (information regarding the layer thickness in the thickness direction of multiple layers in the substrate WF and the refractive index of said multiple layers).

[0050] The display unit 93 is configured using, for example, a liquid crystal display. The input / output control unit 94 displays on the display unit 93 the GUI (Graphical User Interface) necessary for operating the inspection optical device 10, images of the inside of the substrate WF transmitted from the inspection optical device 10 (optical device control unit 80), and the determination results of the determination unit 96 regarding the presence or absence of defects inside the substrate WF. The input / output control unit 94 transmits, for example, setting information for the focusing position of the first irradiation light La and information regarding the configuration of the substrate WF, which are input from the input unit 92, from the interface unit 91 to the optical device control unit 80 of the inspection optical device 10.

[0051] The determination unit 96 determines whether or not there are defects inside the substrate WF based on the image data of the inside of the substrate WF stored in the storage unit 95. If there are defects inside the substrate WF (for example, crystal defects), multiphoton excitation by irradiation with the first irradiation light La becomes less likely to occur in the defective area inside the substrate WF, so the defective area appears darker in the image of the inside of the substrate WF. For this reason, the determination unit 96 may determine whether or not there are defects inside the substrate WF by identifying the area in the image of the inside of the substrate WF where the brightness value (grayscale value) is lower than a predetermined threshold as a defective area. The determination result of the determination unit 96 regarding the presence or absence of defects inside the substrate WF is stored in the storage unit 95.

[0052] In the defect inspection apparatus 1 configured as described above, when inspecting a substrate WF, the interface unit 81 of the inspection optical device 10 receives setting information for the focusing position of the first irradiation light La and substrate configuration information transmitted from the interface unit 91 of the information processing device 90. The input setting information for the focusing position of the first irradiation light La and substrate configuration information are stored in the storage unit 85 of the optical device control unit 80. The optical device control unit 80 controls the lens movement unit 69 of the surface detection unit 55 so that the first irradiation light La is focused at the focusing position inside the substrate WF.

[0053] Here, the operation of the focus adjustment lens 67 driven by the lens movement unit 69 will be explained with reference to Figures 5 to 7. Note that only the components necessary for the explanation are shown in Figures 5 to 7. As shown in Figure 5, when the concave lens 67b of the focus adjustment lens 67 is moved by the lens movement unit 69 to a predetermined close position close to the convex lens 67a, the imaging position PS of the image at the slit aperture 63a of the second illumination light Lb irradiated from the objective optical system 15 coincides with the focal position PF of the objective optical system 15. In this case, the second illumination light Lb becomes parallel light in front of and behind the focus adjustment lens 67. In this state, when the optical device control unit 80 performs the autofocus control described later, the focal position PF of the objective optical system 15 is positioned on the surface of the substrate WF.

[0054] As shown in Figure 6, when the lens movement unit 69 moves the concave lens 67b of the focal position adjustment lens 67 away from the convex lens 67a by a distance x, the imaging position PS of the slit aperture 63a of the second illumination light Lb moves by a predetermined distance (also called offset amount L) in the direction toward the objective optical system 15 (-Z direction) from the focal position PF of the objective optical system 15. In this state, when the optical device control unit 80 performs autofocus control, which will be described later, the stage 11 moves in the -Z direction by the stage movement unit 12, and the surface of the substrate WF also moves in the -Z direction, so that as shown in Figure 7, the imaging position PS of the slit aperture 63a of the second illumination light Lb is located on the surface of the substrate WF. As a result, the focal position PF of the objective optical system 15 is located inside the substrate WF, and the first illumination light La emitted from the objective optical system 15 can be focused inside the substrate WF. It should also be said that the focal position PF of the objective optical system 15 is the focusing position of the first illumination light La. The imaging position PS of the image formed at the slit aperture 63a of the second illumination light Lb irradiated from the objective optical system 15 can also be said to be the focusing position of the second illumination light Lb.

[0055] [Autofocus control] Next, autofocus control by the optical device control unit 80 utilizing the surface detection unit 55 will be described. As shown in Figure 4, the second illumination light Lb emitted from the second light source 60 of the surface detection unit 55 is incident on the second illumination optical system 61. The second illumination light Lb incident on the second illumination optical system 61 is focused by the first collector lens 62 and passes through the slit opening 63a of the slit plate 63. The second illumination light Lb that has passed through the slit opening 63a passes through the second collector lens 64 and goes through the first pupil limiting mask 65. A portion of the second illumination light Lb that has passed through the first pupil limiting mask 65 passes through the half mirror 66 and is incident on the focal position adjustment lens 67. The second illumination light Lb that has passed through the focal position adjustment lens 67 passes through the bandpass filter 68 and is reflected by the second dichroic mirror 35. The second illumination light Lb reflected by the second dichroic mirror 35 is irradiated toward the substrate WF by the objective optical system 15 and focused.

[0056] The second illumination light Lb, irradiated from the objective optical system 15 toward the substrate WF, is reflected by the surface of the substrate WF and enters the objective optical system 15 again. The reflected light Le (second illumination light Lb) from the surface of the substrate WF that enters the objective optical system 15 passes through the objective optical system 15 and is reflected by the second dichroic mirror 35. The reflected light Le reflected by the second dichroic mirror 35 passes through the bandpass filter 68 and enters the focal position adjustment lens 67. A portion of the reflected light Le that has passed through the focal position adjustment lens 67 is reflected by the half mirror 66. The reflected light Le reflected by the half mirror 66 is focused by the second objective lens 72 for receiving light of the second light receiving optical system 71. The reflected light Le focused by the second objective lens 72 for receiving light passes through the first relay lens 73 for receiving light and through the second pupil limiting mask 74. The reflected light Le that has passed through the second pupil limiting mask 74 is transmitted through the second relay lens 75 and the cylindrical lens 76 for receiving light. The reflected light Le that has passed through the cylindrical lens 76 is focused and reaches the detection surface 79 of the second detector 78. The second detector 78 receives the image of the slit aperture 63a formed on the detection surface 79, performs photoelectric conversion, and outputs a second received signal.

[0057] Furthermore, when the Z position of the substrate WF surface changes, the distance between the substrate WF surface and the objective optical system 15 changes, which in turn changes the reflection position of the second irradiated light Lb on the substrate WF surface. When the reflection position of the second irradiated light Lb on the substrate WF surface changes, the position of the image of the slit aperture 63a formed on the detection surface 79 of the second detector 78 changes in the direction of extension of the detection surface 79 (the short-side direction of the image of the slit aperture 63a). Therefore, based on the second received signal output from the second detector 78, it is possible to determine the imaging position of the slit aperture 63a on the substrate WF surface in the optical axis direction of the objective optical system 15 (the focusing position of the second irradiated light Lb). In addition, based on the second received signal output from the second detector 78, it is also possible to determine the position of the substrate WF surface in the optical axis direction of the objective optical system 15 or in a direction parallel to the optical axis direction.

[0058] The second light-receiving signal output from the second detector 78 is acquired by the data acquisition unit 86. Based on the second light-receiving signal acquired by the data acquisition unit 86, the calculation unit 88 determines a control signal for autofocus control that controls the stage moving unit 12 so that the imaging position of the image at the slit aperture 63a (the focusing position of the second irradiation light Lb) is located on the surface of the substrate WF. The optical device control unit 80 outputs the control signal for autofocus control determined by the calculation unit 88 to the stage moving unit 12 and controls the stage moving unit 12. Alternatively, the calculation unit 88 may determine a control signal for autofocus control based on the results of scanning the second light-receiving signals output from multiple detection pixels (not shown) of the second detector 78 along the detection surface 79, for example, as disclosed in U.S. Patent No. 7,071,451.

[0059] When focusing the first irradiation light La into one of the layers of a substrate WF, it is necessary to adjust the focusing position of the first irradiation light La in order to correct the aberrations that occur in each layer of the substrate WF located between the focusing position of the first irradiation light La and the surface of the substrate WF. Hereafter, the aberrations that occur in each layer of the substrate WF located between the focusing position of the first irradiation light La and the surface of the substrate WF may be referred to as index mismatch aberrations. The index mismatch aberration Wi(kp) that occurs in the i-th layer (where i is an integer of 1 or more) counting from the surface side of the substrate WF is expressed by the following equation (1) in the range where the paraxial approximation holds.

[0060]

number

[0061] Furthermore, among the multiple layers in the substrate WF, the i-th layer counted from the surface side of the substrate WF is also one of the layers located between the focal point of the first irradiated light La and the surface of the substrate WF. The refractive index of the i-th layer counted from the surface side of the substrate WF is the refractive index with respect to the wavelength of the first irradiated light La, similar to the refractive index in the substrate configuration information. kp is the coordinate in the space obtained by the Fourier transform of real space, i.e., the pupil coordinate (coordinate in wavenumber space).

[0062] Next, we will describe the case where the first irradiation light La is focused at a depth d#m from the interface of the m-th layer (where m is an integer greater than or equal to 2) counting from the surface side of the substrate WF. In this case, the total index mismatch aberration W that occurs between the focusing position of the first irradiation light La and the surface of the substrate WF is M (kp) is expressed by the following equation (2).

[0063]

number

[0064] The calculation unit 88 calculates the total index mismatch aberration W based on the substrate configuration information, the setting information for the focusing position of the first irradiation light La, and the opening angle information for the first irradiation light La stored in the storage unit 85. M The (kp) is calculated. More specifically, the calculation unit 88 calculates the total index mismatch aberration W based on the layer thickness in the thickness direction of the multiple layers in the substrate WF, the refractive index of the multiple layers, the focusing position of the first irradiated light La set inside one of the multiple layers in the substrate WF, and the opening angle of the first irradiated light La. M (kp) is calculated. Then, the calculation unit 88 calculates |W M (kp)-W L The offset amount L of the focusing position of the second irradiation light Lb relative to the focusing position of the first irradiation light La is calculated and determined such that the value of (kp)| is minimized. Here, W L (kp) is the aberration that occurs when the focusing position of the first irradiated light La is shifted by an offset amount L in the optical axis direction of the objective optical system 15, and is expressed by the following equation (3).

[0065] [Number] However, n0: refractive index of air

[0066] The calculation unit 88 obtains the offset amount L of the condensing position of the second irradiation light Lb with respect to the condensing position of the first irradiation light La by using the expressions (2) and (3), and adjusts the condensing position of the first irradiation light La. Thereby, it is possible to correct the index mismatch aberration generated in each layer of the substrate WF, that is, the total index mismatch aberration for each layer of the substrate WF. For example, the calculation unit 88 may obtain the offset amount L by using the following expression (4) approximately obtained from the expression of |W M (kp) - W L (kp)|.

[0067] [Number]

[0068] Further, the calculation unit 88 may obtain the offset amount L from the condensing position (depth from the surface of the substrate WF) of the first irradiation light La set inside the substrate WF based on the condensing position adjustment data table created in advance by optical simulation. The condensing position adjustment data table includes information regarding the ratio m L of the change in the offset amount L of the condensing position of the second irradiation light Lb with respect to the condensing position of the first irradiation light La and the change in the depth d from the surface or interface of the substrate WF. Hereinafter, this ratio m L is referred to as the L-d change ratio m L .

[0069] The L-d change ratio m LTo determine this, first, the layer thicknesses in the thickness direction of multiple layers in the substrate WF, the refractive indices of these multiple layers, and the focusing position of the first irradiating light La are set. Next, based on the layer thickness and refractive index of the first layer LY1 in the substrate WF, the focusing position of the first irradiating light La set inside the first layer LY1, and the opening angle of the first irradiating light La, the offset amount L is determined by calculating, for example, the Strehl ratio of the PFS (point image distribution function) when the focusing position of the first irradiating light La is at a depth d from the surface of the substrate WF in the first layer LY1. Next, the offset amount L is determined for multiple depths d from the surface of the substrate WF in the first layer LY1, and a plot of the offset amount L for multiple depths d from the surface of the substrate WF in the first layer LY1 is created. Next, the Ld change ratio m in the first layer LY1 is determined by fitting the created plot with, for example, a straight line. L We seek.

[0070] Next, based on the layer thickness and refractive index of the second layer LY2 in the substrate WF, the focusing position of the first irradiating light La set inside the second layer LY2, and the opening angle of the first irradiating light La, the offset amount L is determined when the focusing position of the first irradiating light La is at a depth d from the interface of the substrate WF in the second layer LY2 by calculating, for example, the Strehl ratio of the PFS (point image distribution function) of the first irradiating light La. Next, the offset amount L is determined for multiple depths d from the interface of the substrate WF in the second layer LY2 by determining the offset amount L for multiple depths d from the interface of the substrate WF in the second layer LY2, and a plot of the offset amount L for multiple depths d from the interface of the substrate WF in the second layer LY2 is created. Next, the Ld change ratio m in the second layer LY2 is determined by fitting the created plot with, for example, a straight line. L Then, similar to the case of the second layer LY2, the Ld change ratio m in each layer from the third layer LY3 onwards is calculated. L The calculation unit 88 calculates the Ld change ratio m in each layer of the substrate WF included in the light collection position adjustment data table. L Therefore, it is possible to determine the offset amount L from the focusing position of the first irradiation light La set by the user.

[0071] The optical device control unit 80 outputs a control signal to the lens movement unit 69 of the surface detection unit 55 that provides the offset amount L determined by the calculation unit 88. The lens movement unit 69 moves the concave lens 67b of the focal position adjustment lens 67 in accordance with the control signal output from the optical device control unit 80. As a result, the focusing position of the second illumination light Lb irradiated from the objective optical system 15 (the imaging position of the image at the slit aperture 63a of the second illumination light Lb) is shifted by an offset amount L from the focusing position of the first illumination light La irradiated from the objective optical system 15 (the focal position of the objective optical system 15). In this state, the optical device control unit 80 performs autofocus control, which allows the focusing position of the first illumination light La irradiated from the objective optical system 15 to be aligned with the focusing position of the first illumination light La set inside one of the layers of the substrate WF.

[0072] [Example of inspection of the second layer LY2 in a substrate waterfall (WF)] In the example shown in Figure 2, when the focusing position of the first irradiated light La is set inside the second layer LY2 in the substrate WF, as shown in Figure 8, the calculation unit 88 sets m=2|W M (kp)-W L The offset amount L of the focusing position of the second irradiation light Lb relative to the focusing position of the first irradiation light La is calculated to minimize the value of (kp). Hereafter, for the sake of explanation, the offset amount L when the focusing position of the first irradiation light La is set inside the second layer LY2 in the substrate WF may be referred to as offset amount L(LY2).

[0073] The optical device control unit 80 outputs a control signal to the lens movement unit 69 of the surface detection unit 55 that provides the offset amount L(LY2) determined by the calculation unit 88. The lens movement unit 69 moves the concave lens 67b of the focal position adjustment lens 67 in accordance with the control signal output from the optical device control unit 80. As a result, the focusing position of the second illumination light Lb irradiated from the objective optical system 15 moves by an offset amount L(LY2) from the focusing position of the first illumination light La irradiated from the objective optical system 15. In this state, the optical device control unit 80 performs autofocus control, which allows the focusing position of the first illumination light La irradiated from the objective optical system 15 to be aligned with the focusing position of the first illumination light La set inside the second layer LY2 of the substrate WF.

[0074] The optical device control unit 80 controls the first light source unit 20 (first light source 21) to irradiate the first illumination light La toward the substrate WF when the focusing position of the first illumination light La in the optical axis direction (Z direction) of the objective optical system 15 is located inside the substrate WF. On the other hand, the optical device control unit 80 controls the first light source unit 20 (first light source 21) to restrict the irradiation of the first illumination light La toward the substrate WF when the focusing position of the first illumination light La is not located inside the substrate WF. This prevents the first illumination light La irradiated from the objective optical system 15 from being focused on the surface of the substrate WF. Therefore, it is possible to suppress the phenomenon of sublimation or evaporation of the surface portion of the substrate WF (also called ablation). Furthermore, even if the focusing position of the first irradiation light La is located on or above the surface of the substrate WF, if ablation does not occur on the surface portion of the substrate WF, the optical device control unit 80 does not need to restrict the irradiation of the first irradiation light La toward the substrate WF when the focusing position of the first irradiation light La in the optical axis direction (Z direction) of the objective optical system 15 is not located inside the substrate WF.

[0075] The movement distance x of the concave lens 67b of the focal position adjustment lens 67, which is moved by the lens movement unit 69, is measured by, for example, an encoder (not shown). The encoder outputs a measurement signal of the movement distance x of the concave lens 67b to the optical device control unit 80. The memory unit 85 of the optical device control unit 80 stores in advance the relationship between the offset amount L of the focal position of the combined optical system of the second illumination optical system 61 and the objective optical system 15 with respect to the focal position of the objective optical system 15, and the movement distance x of the concave lens 67b. The optical device control unit 80 uses the relationship between the offset amount L and the movement distance x stored in the memory unit 85 to determine the focusing position of the first illumination light La in the optical axis direction (Z direction) of the objective optical system 15 from the measurement signal of the movement distance x of the concave lens 67b output from the encoder. The optical device control unit 80 then determines whether the determined focusing position of the first illumination light La is located inside the second layer LY2 of the substrate WF.

[0076] Under the control of the optical device control unit 80, the laser light emitted from the first light source 21 is shaped by the light source lens 22 into parallel light and emitted from the first light source unit 20 as the first irradiation light La. The first irradiation light La emitted from the first light source unit 20 passes through the first dichroic mirror 31 of the first irradiation optical system 30 and is incident on the deflection unit 32. The first irradiation light La incident on the deflection unit 32 is reflected in that order by the X-direction deflection mirror 32a and the Y-direction deflection mirror 32b and is incident on the first relay lens 33. The first irradiation light La that has passed through the first relay lens 33 is focused on the first intermediate image plane Im1 and is incident on the second relay lens 34. The first irradiation light La that has passed through the second relay lens 34 becomes parallel light and passes through the second dichroic mirror 35. The first illumination light La that has passed through the second dichroic mirror 35 is directed toward the substrate WF by the objective optical system 15 and focused at a focal position set within the second layer LY2 in the substrate WF.

[0077] When the first irradiation light La is irradiated onto the substrate WF, the deflection unit 32 of the first irradiation optical system 30 scans the interior of the second layer LY2 in the substrate WF with the first irradiation light La from the first light source unit 20. After the deflection unit 32 scans the interior of the second layer LY2 in the observation area of ​​the substrate WF facing the objective optical system 15, the optical device control unit 80 outputs a control signal to the stage moving unit 12 to move the stage 11 in the X or Y direction. By moving the stage 11 in the X or Y direction using the stage moving unit 12, the observation area of ​​the substrate WF facing the objective optical system 15 can be displaced in the X or Y direction. Even if the observation area of ​​the substrate WF is displaced in the X or Y direction, the autofocus control of the optical device control unit 80 maintains the focusing position of the first irradiation light La in the optical axis direction of the objective optical system 15 inside the second layer LY2.

[0078] The detection light Ld generated inside the second layer LY2 (irradiation region 25) of the substrate WF by multiphoton excitation with the first irradiation light La is incident on the objective optical system 15. The detection light Ld from the substrate WF incident on the objective optical system 15 passes through the objective optical system 15, becomes parallel light, and passes through the second dichroic mirror 35. The detection light Ld that has passed through the second dichroic mirror 35 is incident on the second relay lens 34. The detection light Ld that has passed through the second relay lens 34 is focused on the first intermediate image plane Im1 and incident on the first relay lens 33. The detection light Ld that has passed through the first relay lens 33 becomes parallel light and is incident on the deflection section 32. The detection light Ld that has been incident on the deflection section 32 is reflected in this order by the Y-direction deflection mirror 32b and the X-direction deflection mirror 32a, and is reflected by the first dichroic mirror 31.

[0079] The detection light Ld reflected by the first dichroic mirror 31 passes through the barrier filter 42 of the first light-receiving optical system 41 and enters the focusing lens 43. The detection light Ld that has passed through the focusing lens 43 is focused on the second intermediate image plane Im2 and enters the magnification optical system 45. The detection light Ld that has passed through the magnification optical system 45 is focused on the image plane Imp (detection surface 52 of the first detector 51) and forms an image 49 of the illuminated area 25 inside the second layer LY2 of the substrate WF. The first detector 51 receives the image 49 of the illuminated area 25 with multiple detection pixels 53, performs photoelectric conversion, and outputs a first light-receiving signal.

[0080] The first light-receiving signal output from the first detector 51 is acquired by the data acquisition unit 86. Based on the first light-receiving signals output from multiple detection pixels 53 of the first detector 51, acquired by the data acquisition unit 86, the image processing unit 87 generates image data of the cross-section of the second layer LY2 of the substrate WF in the XY direction (a direction perpendicular to the thickness direction of the substrate WF). The image data of the cross-section of the second layer LY2 of the substrate WF in the XY direction, generated by the image processing unit 87, is transmitted from the interface unit 81 to the information processing device 90.

[0081] Image data of the cross-section in the XY direction of the second layer LY2 of the substrate WF, transmitted from the interface unit 81 of the inspection optical device 10 (optical device control unit 80), is input to the interface unit 91 of the information processing device 90. The image data of the cross-section in the XY direction of the second layer LY2 of the substrate WF input to the interface unit 91 is stored in the storage unit 95. The determination unit 96 determines whether or not there is a defect in the second layer LY2 of the substrate WF based on the image data of the cross-section in the XY direction of the second layer LY2 of the substrate WF stored in the storage unit 95. The determination result of the determination unit 96 regarding the presence or absence of a defect in the second layer LY2 of the substrate WF is stored in the storage unit 95.

[0082] [Example of inspection of the third layer LY3 in a substrate waterfall] Furthermore, as shown in Figure 9, when the focusing position of the first irradiated light La is set inside the third layer LY3 in the substrate WF, the calculation unit 88 sets m=3|W M (kp)-W LThe offset amount L of the focusing position of the second irradiation light Lb relative to the focusing position of the first irradiation light La is calculated to minimize the value of (kp). Hereafter, for the sake of explanation, the offset amount L when the focusing position of the first irradiation light La is set inside the third layer LY3 of the substrate WF may be referred to as offset amount L(LY3). Note that L(LY3) > L(LY2).

[0083] The optical device control unit 80 outputs a control signal to the lens movement unit 69 of the surface detection unit 55 that provides the offset amount L(LY3) determined by the calculation unit 88. The lens movement unit 69 moves the concave lens 67b of the focal position adjustment lens 67 in accordance with the control signal output from the optical device control unit 80. As a result, the focusing position of the second illumination light Lb irradiated from the objective optical system 15 moves by an offset amount L(LY3) from the focusing position of the first illumination light La irradiated from the objective optical system 15. In this state, the optical device control unit 80 performs autofocus control, which allows the focusing position of the first illumination light La irradiated from the objective optical system 15 to be aligned with the focusing position of the first illumination light La set inside the third layer LY3 of the substrate WF. In this way, by changing the offset amount L of the focusing position of the second illumination light Lb relative to the focusing position of the first illumination light La, the focusing position of the first illumination light La irradiated from the objective optical system 15 can be matched to the focusing position of the first illumination light La set inside different layers in the substrate WF.

[0084] Similar to the example of inspecting the second layer LY2 in the substrate WF, the optical device control unit 80 controls the first light source unit 20 (first light source 21) to irradiate the first illumination light La toward the substrate WF when the focusing position of the first illumination light La in the optical axis direction (Z direction) of the objective optical system 15 is located inside the substrate WF. On the other hand, the optical device control unit 80 controls the first light source unit 20 (first light source 21) to restrict the irradiation of the first illumination light La toward the substrate WF when the focusing position of the first illumination light La is not located inside the substrate WF.

[0085] The laser light emitted from the first light source 21 under the control of the optical device control unit 80 is shaped into parallel light by the light source lens 22 and emitted from the first light source unit 20 as the first irradiation light La. The first irradiation light La emitted from the first light source unit 20 is irradiated toward the substrate WF by the first irradiation optical system 30 and the objective optical system 15, similar to the example of inspecting the second layer LY2 in the substrate WF, and is focused at a focal position set inside the third layer LY3 in the substrate WF.

[0086] When the first irradiation light La is irradiated onto the substrate WF, the deflection unit 32 of the first irradiation optical system 30 scans the interior of the third layer LY3 in the substrate WF with the first irradiation light La from the first light source unit 20. After the deflection unit 32 scans the interior of the third layer LY3 in the observation area of ​​the substrate WF facing the objective optical system 15, the optical device control unit 80 outputs a control signal to the stage movement unit 12 to move the stage 11 in the X or Y direction. By moving the stage 11 in the X or Y direction using the stage movement unit 12, the observation area of ​​the substrate WF facing the objective optical system 15 can be displaced in the X or Y direction. Even if the observation area of ​​the substrate WF is displaced in the X or Y direction, the autofocus control of the optical device control unit 80 maintains the focusing position of the first irradiation light La in the optical axis direction of the objective optical system 15 inside the third layer LY3.

[0087] The detection light Ld generated inside the third layer LY3 (irradiated area 25) of the substrate WF by multiphoton excitation with the first irradiation light La is incident on the objective optical system 15. The detection light Ld from the substrate WF that has been incident on the objective optical system 15 is focused onto the image plane Imp (detection surface 52 of the first detector 51) by the first photoreceiving optical system 41, similar to the example of inspecting the second layer LY2 of the substrate WF, and forms an image 49 of the illuminated area 25 inside the third layer LY3 of the substrate WF. The first detector 51 receives the image 49 of the illuminated area 25 with multiple detection pixels 53, performs photoelectric conversion, and outputs a first photodetection signal.

[0088] The first light-receiving signal output from the first detector 51 is acquired by the data acquisition unit 86. Based on the first light-receiving signals output from multiple detection pixels 53 of the first detector 51, acquired by the data acquisition unit 86, the image processing unit 87 generates image data of the cross-section of the third layer LY3 of the substrate WF in the XY direction (a direction perpendicular to the thickness direction of the substrate WF). The image data of the cross-section of the third layer LY3 of the substrate WF in the XY direction, generated by the image processing unit 87, is transmitted from the interface unit 81 to the information processing device 90.

[0089] Image data of the cross-section in the XY direction of the third layer LY3 of the substrate WF, transmitted from the interface unit 81 of the inspection optical device 10 (optical device control unit 80), is input to the interface unit 91 of the information processing device 90. The image data of the cross-section in the XY direction of the third layer LY3 of the substrate WF input to the interface unit 91 is stored in the storage unit 95. The determination unit 96 determines whether or not there is a defect in the third layer LY3 of the substrate WF based on the image data of the cross-section in the XY direction of the third layer LY3 of the substrate WF stored in the storage unit 95. The determination result of the determination unit 96 regarding the presence or absence of a defect in the third layer LY3 of the substrate WF is stored in the storage unit 95.

[0090] [Characteristic configuration of the first embodiment] According to the first embodiment, the optical device control unit 80 outputs a control signal for autofocus control, in other words, a control signal that controls the positional relationship between the focusing position of the first irradiated light La in the optical axis direction of the objective optical system 15 and the position of the substrate WF, to the stage moving unit 12 based on substrate configuration information relating to the configuration of the substrate WF, the second light receiving signal output from the second detector 78 of the second light receiving unit 70, and setting information for the focusing position of the first irradiated light La. This makes it possible to improve the positional accuracy of the focusing position of the first irradiated light La and to improve the accuracy of inspection in defect inspection inside the substrate WF.

[0091] Furthermore, the optical device control unit 80 may output a control signal for autofocus control to the stage moving unit 12 based on the substrate configuration information, the second light-receiving signal output from the second detector 78 of the second light-receiving unit 70, and the setting information for the focusing position of the first irradiation light La. This makes it possible to use the setting information for the focusing position of the first irradiation light La to align the focusing position of the first irradiation light La irradiated from the objective optical system 15 with the focusing position of the first irradiation light La set inside one of the multiple layers of the substrate WF. As a result, the positional accuracy of the focusing position of the first irradiation light La can be increased, and the accuracy of inspection in defect inspection inside the substrate WF can be increased.

[0092] The substrate configuration information may include information on multiple layers stacked in the thickness direction of the substrate WF. For example, the substrate configuration information may include information on the layer thickness in the thickness direction of the multiple layers in the substrate WF and the refractive index of those multiple layers. This makes it possible to correct aberrations (index mismatch aberrations) that occur in each layer of the multiple layers in the substrate WF that are located between the focusing position of the first irradiated light La and the surface of the substrate WF.

[0093] Furthermore, the optical device control unit 80 may output a control signal for autofocus control to the stage moving unit 12 based on substrate configuration information including information on the thickness of multiple layers in the thickness direction and the refractive index of the multiple layers in the substrate WF, a second light-receiving signal output from the second detector 78 of the second light-receiving unit 70, setting information for the focusing position of the first irradiated light La, and information for the opening angle of the first irradiated light La directed from the objective optical system 15 toward the substrate WF. This allows the focusing position of the first irradiated light La emitted from the objective optical system 15 to be corrected according to the aforementioned index mismatch aberration, thereby aligning it with the focusing position of the first irradiated light La set inside one of the multiple layers in the substrate WF. As a result, the positional accuracy of the focusing position of the first irradiated light La can be increased, and the accuracy of inspection in defect inspection inside the substrate WF can be increased.

[0094] Furthermore, the optical device control unit 80 may output a control signal to the stage moving unit 12 that can correct the index mismatch aberration Wi(kp) represented by the above-mentioned equation (1). The optical device control unit 80 also corrects the total index mismatch aberration W represented by the above-mentioned equation (2). M A control signal capable of correcting (kp) may be output to the stage movement unit 12. This allows the focusing position of the first illumination light La irradiated from the objective optical system 15 to be aligned with the focusing position of the first illumination light La set inside one of the multiple layers in the substrate WF. As a result, the positional accuracy of the focusing position of the first illumination light La can be increased, and the accuracy of inspection in defect inspection inside the substrate WF can be increased.

[0095] The optical device control unit 80 may include an interface unit 81 (input unit) into which substrate configuration information is input, and a storage unit 85 that stores the substrate configuration information input to the interface unit 81. The optical device control unit 80 may also include a calculation unit 88 that calculates a control signal to be output to the stage movement unit 12 using the substrate configuration information stored in the storage unit 85. This allows the substrate configuration information used to calculate the control signal to be output to the stage movement unit 12 to be input from outside the inspection optical device 10.

[0096] The first irradiation light La, which is irradiated from the objective optical system 15 toward the substrate WF, may be pulsed light having a pulse width of less than 1 picosecond. Such first irradiation light La may cause multiphoton excitation inside the substrate WF. The first light receiving unit 40 may receive the light generated by multiphoton excitation inside the substrate WF. This makes it possible to increase the positional accuracy of the light generated inside the substrate WF, and thus improve the accuracy of inspection in defect inspection inside the substrate WF.

[0097] Furthermore, the information processing device 90 may be provided with a determination unit 96 that determines the presence or absence of defects inside the substrate WF based on image data of the inside of the substrate WF generated by the inspection optical device 10. As described above, by increasing the positional accuracy of the focusing position of the first irradiation light La, it is possible to increase the accuracy of inspection in defect inspection inside the substrate WF. The determination unit 96 may also be provided in the optical device control unit 80 of the inspection optical device 10.

[0098] In the first embodiment described above, the optical device control unit 80 may control the first light source unit 20 (first light source 21) to irradiate the first illumination light La toward the substrate WF when the focusing position of the first illumination light La in the optical axis direction of the objective optical system 15 is located inside the substrate WF. Alternatively, the optical device control unit 80 may control the first light source unit 20 (first light source 21) to restrict the irradiation of the first illumination light La toward the substrate WF when the focusing position of the first illumination light La in the optical axis direction of the objective optical system 15 is not located inside the substrate WF. This prevents the first illumination light La irradiated from the objective optical system 15 from being focused on the surface of the substrate WF. Therefore, it is possible to suppress the phenomenon of sublimation or evaporation of the surface portion of the substrate WF (also called ablation).

[0099] In the first embodiment described above, the setting information for the focusing position of the first illumination light La may include multiple positions within the substrate WF where the optical axis position (Z position) of the objective optical system 15 is different. For example, the focusing position of the first illumination light La may be set inside the second layer LY2 in the substrate WF and inside the third layer LY3 in the substrate WF. In this case, the calculation unit 88 may determine an offset amount L for the multiple pre-set focusing positions of the first illumination light La, and the optical device control unit 80 may output a control signal to the lens movement unit 69 of the surface detection unit 55 that provides the offset amount L determined by the calculation unit 88. By performing autofocus control on the multiple pre-set focusing positions of the first illumination light La, the optical device control unit 80 can adjust the focusing position of the first illumination light La irradiated from the objective optical system 15 to match the multiple focusing positions of the first illumination light La set inside the substrate WF. Then, the first irradiation optical system 30 irradiates the first irradiation light La at a plurality of pre-set focal positions of the first irradiation light La, the first light receiving unit 40 receives the light (detection light Ld) generated inside the substrate WF and outputs a first light reception signal, and the image processing unit 87 generates image data of multiple cross-sections inside the substrate WF where the optical axis position (Z position) of the objective optical system 15 is different, based on the first light reception signal from the first light receiving unit 40. This makes it possible to obtain images of multiple cross-sections inside the substrate WF where the optical axis position (Z position) of the objective optical system 15 is different, i.e., a Z-stack image of the inside of the substrate WF.

[0100] [Second Embodiment] Next, a defect inspection apparatus according to the second embodiment will be described. The defect inspection apparatus according to the second embodiment has a configuration that is common to the defect inspection apparatus 1 according to the first embodiment, except that it further includes a surface detection deflection unit. For this reason, the same reference numerals as in the first embodiment are used for components that are similar to those in the first embodiment, and detailed descriptions are omitted. In the defect inspection apparatus according to the second embodiment, as shown in Figure 10, a surface detection deflection unit 150 is provided between the second dichroic mirror 35 and the surface detection unit 55.

[0101] The surface detection deflection unit 150 comprises a surface detection deflection mirror 151, a first surface detection relay lens 155, and a second surface detection relay lens 156. The surface detection deflection mirror 151 is constructed using a galvanometer mirror, a MEMS mirror, a resonant mirror (resonant mirror), or the like. The surface detection deflection mirror 151 is positioned at a location that is the conjugate plane of the pupil plane Pp of the objective optical system 15, or in the vicinity of a location that is the conjugate plane of the pupil plane Pp of the objective optical system 15. The surface detection deflection mirror 151 reflects the second illumination light Lb that has passed through the bandpass filter 68 of the surface detection unit 55 toward the first surface detection relay lens 155. The surface detection deflection mirror 151 may be rotatable around a single axis of rotation, or it may be rotatable around two axes of rotation. For example, when the surface detection deflection mirror 151 rotates in a predetermined rotational direction, the direction of propagation of the second irradiation light Lb changes, and the irradiation position of the second irradiation light Lb on the surface of the substrate WF moves in the X direction.

[0102] The first surface detection relay lens 155 focuses the second illumination light Lb reflected by the surface detection deflection mirror 151. The second surface detection relay lens 156 guides the second illumination light Lb from the first surface detection relay lens 155 to the second dichroic mirror 35. The second surface detection relay lens 156 also focuses the reflected light Le from the objective optical system 15 (second dichroic mirror 35). The first surface detection relay lens 155 guides the reflected light Le from the second surface detection relay lens 156 to the surface detection deflection mirror 151. Note that the first surface detection relay lens 155 and the second surface detection relay lens 156 are not limited to a single lens, but may be composed of multiple lenses.

[0103] In the defect inspection apparatus according to the second embodiment, the second irradiation light Lb emitted from the second light source 60 of the surface detection unit 55 is incident on the surface detection deflection mirror 151 of the surface detection deflection unit 150 via the second irradiation optical system 61, similar to the first embodiment. The second irradiation light Lb reflected by the surface detection deflection mirror 151 is focused by the first surface detection relay lens 155. The second irradiation light Lb focused by the first surface detection relay lens 155 passes through the second surface detection relay lens 156 and is reflected by the second dichroic mirror 35. The second irradiation light Lb reflected by the second dichroic mirror 35 is irradiated toward the substrate WF by the objective optical system 15 and focused.

[0104] The second illumination light Lb, irradiated from the objective optical system 15 toward the substrate WF, is reflected by the surface of the substrate WF and enters the objective optical system 15 again. The reflected light Le (second illumination light Lb) from the surface of the substrate WF that enters the objective optical system 15 is transmitted through the objective optical system 15 and reflected by the second dichroic mirror 35. The reflected light Le reflected by the second dichroic mirror 35 is focused by the second relay lens 156 for surface detection of the surface detection deflection unit 150. The reflected light Le focused by the second relay lens 156 for surface detection is transmitted through the first relay lens 155 for surface detection and reflected by the surface detection deflection mirror 151. The reflected light Le reflected by the surface detection deflection mirror 151 enters the surface detection unit 55. The reflected light Le that enters the surface detection unit 55 is focused on the detection surface 79 of the second detector 78 via the second light receiving optical system 71, similar to the first embodiment. The second detector 78 receives the image from the slit aperture 63a formed on the detection surface 79, performs photoelectric conversion, and outputs a second received signal.

[0105] When inspecting the substrate WF, as in the first embodiment, the setting information for the focusing position of the first irradiation light La and the substrate configuration information are stored in the storage unit 85 of the optical device control unit 80. The optical device control unit 80 controls the lens movement unit 69 of the surface detection unit 55 so that the first irradiation light La is focused at the focusing position inside the substrate WF. At this time, the optical device control unit 80 outputs a control signal to the surface detection deflection mirror 151 of the surface detection deflection unit 150, and controls the surface detection deflection mirror 151 to rotate to the first rotation position shown in Figure 10.

[0106] When the surface detection deflection mirror 151 rotates to the first rotation position, the image of the slit aperture 63a of the second illumination light Lb irradiated from the objective optical system 15 is formed on the optical axis AX of the objective optical system 15. As a result, when the concave lens 67b of the focal position adjustment lens 67 is moved to a predetermined close position by the lens movement unit 69, the image formation position of the image of the slit aperture 63a of the second illumination light Lb irradiated from the objective optical system 15 coincides with the focal position of the objective optical system 15, similar to the first embodiment. Therefore, when the surface detection deflection mirror 151 rotates to the first rotation position, the optical device control unit 80 performs autofocus control in the same manner as in the first embodiment, so that the focusing position of the first illumination light La irradiated from the objective optical system 15 can be aligned with the focusing position of the first illumination light La set inside one of the layers of the substrate WF.

[0107] [Example of inspection of the second layer LY2 in a substrate waterfall (WF)] As shown in Figure 10, when the focusing position of the first irradiating light La is set inside the second layer LY2 of the substrate WF, the optical device control unit 80 can perform autofocus control in the same manner as in the first embodiment, thereby aligning the focusing position of the first irradiating light La emitted from the objective optical system 15 with the focusing position of the first irradiating light La set inside the second layer LY2 of the substrate WF.

[0108] Similar to the first embodiment, the optical device control unit 80 controls the first light source unit 20 (first light source 21) to irradiate the first illumination light La toward the substrate WF when the focusing position of the first illumination light La in the optical axis direction (Z direction) of the objective optical system 15 is located inside the substrate WF. On the other hand, the optical device control unit 80 controls the first light source unit 20 (first light source 21) to restrict the irradiation of the first illumination light La toward the substrate WF when the focusing position of the first illumination light La is not located inside the substrate WF.

[0109] The laser light emitted from the first light source 21 under the control of the optical device control unit 80 is shaped into parallel light by the light source lens 22 and emitted from the first light source unit 20 as the first irradiation light La. The first irradiation light La emitted from the first light source unit 20 is irradiated toward the substrate WF by the first irradiation optical system 30 and the objective optical system 15, similar to the first embodiment, and is focused at a focal position set inside the second layer LY2 of the substrate WF.

[0110] The detection light Ld generated inside the second layer LY2 (irradiated region 25) of the substrate WF by multiphoton excitation with the first irradiation light La is incident on the objective optical system 15. The detection light Ld from the substrate WF incident on the objective optical system 15 is focused on the image plane Imp (detection surface 52 of the first detector 51) by the first photoreceiving optical system 41, as in the first embodiment, and forms an image 49 of the illuminated region 25 inside the second layer LY2 of the substrate WF. The first detector 51 receives the image 49 of the illuminated region 25 with multiple detection pixels 53, performs photoelectric conversion, and outputs a first photoreceiving signal.

[0111] Similar to the first embodiment, the image processing unit 87 generates image data of the cross-section of the second layer LY2 of the substrate WF in the XY direction (a direction perpendicular to the thickness direction of the substrate WF) based on the first light-receiving signals output from a plurality of detection pixels 53 of the first detector 51, which are acquired by the data acquisition unit 86. The image data of the cross-section of the second layer LY2 of the substrate WF in the XY direction generated by the image processing unit 87 is transmitted from the interface unit 81 to the information processing device 90. Similar to the first embodiment, the determination unit 96 of the information processing device 90 determines whether or not there are defects in the second layer LY2 of the substrate WF based on the image data of the cross-section of the second layer LY2 of the substrate WF in the XY direction.

[0112] When the first irradiation light La is irradiated onto the substrate WF, the deflection unit 32 of the first irradiation optical system 30 scans the interior of the first observation area SC1 (second layer LY2) on the substrate WF with the first irradiation light La from the first light source unit 20. During the first period in which the first irradiation light La is irradiated onto the first observation area SC1 of the substrate WF, the optical device control unit 80 outputs a control signal to the surface detection deflection mirror 151 of the surface detection deflection unit 150, controlling the surface detection deflection mirror 151 to rotate to the second rotation position shown in Figure 11. When the surface detection deflection mirror 151 rotates to the second rotation position, the imaging position of the image at the slit aperture 63a of the second irradiation light Lb irradiated from the objective optical system 15 shifts in a direction perpendicular to the optical axis direction of the objective optical system 15 (for example, the X direction) toward the second observation area SC2, which is different from the first observation area SC1.

[0113] The second observation area SC2 may be an area adjacent to the first observation area SC1 in the substrate WF, or it may overlap with a part of the first observation area SC1 in the substrate WF. Alternatively, the second observation area SC2 may be an area separate from the first observation area SC1 in the substrate WF.

[0114] As shown in Figure 10, when the surface detection deflection mirror 151 of the surface detection deflection unit 150 rotates to the first rotation position, the second illumination light Lb irradiated from the objective optical system 15 toward the substrate WF is reflected by the surface of the first observation area SC1 of the substrate WF and enters the objective optical system 15 again. The reflected light Le from the surface of the first observation area SC1 that enters the objective optical system 15 enters the surface detection unit 55 via the second dichroic mirror 35 and the surface detection deflection unit 150, as described above. The reflected light Le from the surface of the first observation area SC1 that enters the surface detection unit 55 is focused onto the detection surface 79 of the second detector 78 via the second light receiving optical system 71, as described above. The second detector 78 receives the image of the slit aperture 63a formed on the detection surface 79, performs photoelectric conversion, and outputs a second light receiving signal of the reflected light Le from the surface of the first observation area SC1.

[0115] During the first period described above, as shown in Figure 11, when the surface detection deflection mirror 151 of the surface detection deflection unit 150 rotates to the second rotation position, the second illumination light Lb irradiated from the objective optical system 15 toward the substrate WF is reflected by the surface of the second observation area SC2 of the substrate WF and enters the objective optical system 15 again. The reflected light Le from the surface of the second observation area SC2 that enters the objective optical system 15 also enters the surface detection unit 55 via the second dichroic mirror 35 and the surface detection deflection unit 150, as described above. The reflected light Le from the surface of the second observation area SC2 that enters the surface detection unit 55 is focused onto the detection surface 79 of the second detector 78 via the second light receiving optical system 71, as described above. The second detector 78 receives the image of the slit aperture 63a formed on the detection surface 79, performs photoelectric conversion, and outputs a second light receiving signal of the reflected light Le from the surface of the second observation area SC2.

[0116] During the first period, the second light-receiving signal output from the second detector 78 is acquired by the data acquisition unit 86. Based on the second light-receiving signal acquired by the data acquisition unit 86, the calculation unit 88 determines a control signal for autofocus control during the second period when the first irradiation light La is irradiated onto the second observation area SC2 of the substrate WF. After the deflection unit 32 of the first irradiation optical system 30 scans the inside of the first observation area SC1 (second layer LY2) of the substrate WF, the optical device control unit 80 outputs a control signal to move the stage 11 in the X or Y direction, and the control signal for autofocus control determined by the calculation unit 88, to the stage movement unit 12. As a result, the optical device control unit 80 moves the stage 11 in the X or Y direction so that the objective optical system 15 faces the second observation area SC2 of the substrate WF, and controls the stage movement unit 12 to move the stage 11 in the Z direction in accordance with the second light-receiving signal output from the second detector 78 during the first period. In this way, the calculation unit 88 determines a control signal for autofocus control in the second period based on the second light-receiving signal output from the second detector 78 in the first period, thereby shortening the time interval between the first period in which the first irradiation light La is irradiated onto the first observation area SC1 of the substrate WF and the second period in which the first irradiation light La is irradiated onto the second observation area SC2 of the substrate WF, and thus shortening the inspection time of the substrate WF.

[0117] Furthermore, during the second period in which the first irradiation light La is irradiated onto the second observation area SC2 of the substrate WF, when the surface detection deflection mirror 151 of the surface detection deflection unit 150 rotates to the second rotation position, the imaging position of the image of the slit aperture 63a of the second irradiation light Lb irradiated from the objective optical system 15 shifts in a direction perpendicular to the optical axis direction of the objective optical system 15 (for example, the X direction) toward a third observation area (not shown) that is different from the second observation area SC2. The positional relationship between the third observation area and the second observation area SC2 is the same as the positional relationship between the second observation area SC2 and the first observation area SC1. Therefore, the optical device control unit 80 can control the stage movement unit 12 in the same way as when scanning the inside of the second observation area SC2 after the first observation area SC1, even when scanning the inside of the third observation area after the second observation area SC2 of the substrate WF, or when scanning the inside of the fourth observation area (not shown) after the third observation area.

[0118] [Example of inspection of the third layer LY3 in a substrate waterfall] When the focusing position of the first irradiation light La is set inside the third layer LY3 in the substrate WF, the focusing position of the first irradiation light La irradiated from the objective optical system 15 can be aligned with the focusing position of the first irradiation light La set inside the third layer LY3 in the substrate WF, similar to the example of inspecting the second layer LY2 in the substrate WF. Therefore, a detailed explanation of the example of inspecting the third layer LY3 in the substrate WF will be omitted.

[0119] [Characteristic configuration of the second embodiment] In the second embodiment, the surface detection unit 55 and the surface detection deflection unit 150 constitute a substrate surface position detection unit that detects the position of the surface of the substrate WF. During the first period in which the first irradiation light La is irradiated onto the first observation area SC1 of the substrate WF, the second irradiation optical system 61 irradiates the surface of the second observation area SC2 of the substrate WF with the second irradiation light Lb via the objective optical system 15, and the second detector 78 of the second light receiving unit 70 receives the second irradiation light Lb reflected from the surface of the second observation area SC2 and outputs a second light receiving signal corresponding to the position of the surface of the second observation area SC2. Then, the calculation unit 88 of the optical device control unit 80 outputs a control signal for autofocus control during the second period in which the first irradiation light La is irradiated onto the second observation area SC2, based on the second light receiving signal corresponding to the position of the surface of the second observation area SC2, to the stage moving unit 12. In other words, it outputs a control signal that controls the positional relationship between the focusing position of the first irradiation light La in the optical axis direction of the objective optical system 15 and the position of the substrate WF. In this way, similar to the first embodiment, the positional accuracy of the focusing position of the first irradiation light La can be increased, making it possible to increase the accuracy of inspection in defect inspection inside the substrate WF. Furthermore, the calculation unit 88 determines a control signal for autofocus control in the second period based on the second light reception signal output from the second detector 78 in the first period, thereby shortening the time interval between the first period in which the first irradiation light La is irradiated onto the first observation area SC1 of the substrate WF and the second period in which the first irradiation light La is irradiated onto the second observation area SC2 of the substrate WF, and thus shortening the inspection time of the substrate WF.

[0120] As described in the first embodiment, the optical device control unit 80 may output a control signal for autofocus control to the stage moving unit 12 based on substrate configuration information, a second light-receiving signal output from the second detector 78 of the second light-receiving unit 70, and setting information for the focusing position of the first irradiation light La. This makes it possible to use the setting information for the focusing position of the first irradiation light La to align the focusing position of the first irradiation light La irradiated from the objective optical system 15 with the focusing position of the first irradiation light La set inside one of the layers of the substrate WF. As a result, the positional accuracy of the focusing position of the first irradiation light La can be increased, and the accuracy of inspection in defect inspection inside the substrate WF can be increased.

[0121] The substrate configuration information may include information on multiple layers stacked in the thickness direction of the substrate WF. For example, the substrate configuration information may include information on the layer thickness in the thickness direction of the multiple layers in the substrate WF and the refractive index of those multiple layers. This makes it possible to correct aberrations (index mismatch aberrations) that occur in each layer of the multiple layers in the substrate WF that are located between the focusing position of the first irradiated light La and the surface of the substrate WF.

[0122] The optical device control unit 80 may output a control signal for autofocus control to the stage moving unit 12 based on substrate configuration information including information on the thickness of multiple layers in the thickness direction and the refractive index of the multiple layers in the substrate WF, a second light-receiving signal output from the second detector 78 of the second light-receiving unit 70, setting information for the focusing position of the first irradiation light La, and information for the opening angle of the first irradiation light La directed from the objective optical system 15 toward the substrate WF. This allows the focusing position of the first irradiation light La irradiated from the objective optical system 15 to be corrected according to the aforementioned index mismatch aberration, thereby aligning it with the focusing position of the first irradiation light La set inside one of the multiple layers in the substrate WF. As a result, the positional accuracy of the focusing position of the first irradiation light La can be increased, and the accuracy of inspection in defect inspection inside the substrate WF can be increased.

[0123] The optical device control unit 80 may output a control signal to the stage moving unit 12 that can correct the index mismatch aberration Wi(kp) represented by the above-mentioned equation (1). The optical device control unit 80 also corrects the total index mismatch aberration W represented by the above-mentioned equation (2). M A control signal capable of correcting (kp) may be output to the stage movement unit 12. This allows the focusing position of the first illumination light La irradiated from the objective optical system 15 to be aligned with the focusing position of the first illumination light La set inside one of the multiple layers in the substrate WF. As a result, the positional accuracy of the focusing position of the first illumination light La can be increased, and the accuracy of inspection in defect inspection inside the substrate WF can be increased.

[0124] The optical device control unit 80 may include an interface unit 81 (input unit) into which substrate configuration information is input, and a storage unit 85 that stores the substrate configuration information input to the interface unit 81. The optical device control unit 80 may also include a calculation unit 88 that calculates a control signal to be output to the stage movement unit 12 using the substrate configuration information stored in the storage unit 85. This allows the substrate configuration information used to calculate the control signal to be output to the stage movement unit 12 to be input from outside the inspection optical device 10.

[0125] The first irradiation light La, which is irradiated from the objective optical system 15 toward the substrate WF, may be pulsed light having a pulse width of less than 1 picosecond. Such first irradiation light La may cause multiphoton excitation inside the substrate WF. The first light receiving unit 40 may receive the light generated by multiphoton excitation inside the substrate WF. This makes it possible to increase the positional accuracy of the light generated inside the substrate WF, and thus improve the accuracy of inspection in defect inspection inside the substrate WF.

[0126] A determination unit 96 may be provided in the information processing device 90 to determine whether or not there are defects inside the substrate WF based on image data of the inside of the substrate WF generated by the inspection optical device. As described above, by increasing the positional accuracy of the focusing position of the first irradiation light La, it is possible to increase the accuracy of inspection in defect inspection inside the substrate WF. The determination unit 96 may also be provided in the optical device control unit 80 of the inspection optical device.

[0127] The optical device control unit 80 may control the first light source unit 20 (first light source 21) to irradiate the first illumination light La toward the substrate WF when the focusing position of the first illumination light La in the optical axis direction of the objective optical system 15 is located inside the substrate WF. Alternatively, the optical device control unit 80 may control the first light source unit 20 (first light source 21) to restrict the irradiation of the first illumination light La toward the substrate WF when the focusing position of the first illumination light La in the optical axis direction of the objective optical system 15 is not located inside the substrate WF. This prevents the first illumination light La irradiated from the objective optical system 15 from being focused on the surface of the substrate WF. Therefore, it is possible to suppress the phenomenon of sublimation or evaporation of the surface portion of the substrate WF (also called ablation).

[0128] Furthermore, the setting information for the focusing position of the first illumination light La may include multiple positions within the substrate WF where the optical axis position (Z position) of the objective optical system 15 is different. For example, the focusing position of the first illumination light La may be set inside the second layer LY2 of the substrate WF and inside the third layer LY3 of the substrate WF. In this case, the calculation unit 88 may determine an offset amount L for the multiple pre-set focusing positions of the first illumination light La, and the optical device control unit 80 may output a control signal to the lens movement unit 69 of the surface detection unit 55 that provides the offset amount L determined by the calculation unit 88. By performing autofocus control on the multiple pre-set focusing positions of the first illumination light La, the optical device control unit 80 can adjust the focusing position of the first illumination light La irradiated from the objective optical system 15 to match the multiple focusing positions of the first illumination light La set inside the substrate WF. Then, the first irradiation optical system 30 irradiates the first irradiation light La at a plurality of pre-set focal positions of the first irradiation light La, the first light receiving unit 40 receives the light (detection light Ld) generated inside the substrate WF and outputs a first light reception signal, and the image processing unit 87 generates image data of multiple cross-sections inside the substrate WF where the optical axis position (Z position) of the objective optical system 15 is different, based on the first light reception signal from the first light receiving unit 40. This makes it possible to obtain images of multiple cross-sections inside the substrate WF where the optical axis position (Z position) of the objective optical system 15 is different, i.e., a Z-stack image of the inside of the substrate WF.

[0129] [Modified version of the second embodiment] In the second embodiment described above, as shown in Figure 12, a surface detection deflection unit 161 may be provided instead of the surface detection deflection mirror 151. For example, the modified surface detection deflection unit 160 may include a surface detection deflection unit 161, a first surface detection relay lens 155, and a second surface detection relay lens 156 (not shown in Figure 12). The surface detection deflection unit 161 is positioned at a location that is the conjugate plane of the pupil plane Pp of the objective optical system 15, or in the vicinity of a location that is the conjugate plane of the pupil plane Pp of the objective optical system 15. The surface detection deflection unit 161 includes a base portion 162, a diffractive optical element 163, and a reflective mirror 164.

[0130] The base portion 162 holds the diffractive optical element 163 and the reflective mirror 164. The diffractive optical element 163 is constructed, for example, using a reflective diffraction grating. The second irradiation light Lb that has passed through the bandpass filter 68 of the surface detection unit 55 is incident on the diffractive optical element 163. From the diffractive optical element 163, the second irradiation light Lb reflected by the diffractive optical element 163 and the diffracted light (for example, +1 diffracted light) diffracted by the diffracting member are emitted toward the first relay lens 155 for surface detection. Hereafter, the diffracted light emitted from the diffractive optical element 163 will be referred to as the second irradiation light Lb# due to diffraction. The reflective mirror 164 reflects the light from the surface of the substrate WF (the second irradiation light Lb reflected by the surface of the substrate WF and the second irradiation light Lb# due to diffraction) that has passed through the first relay lens 155 for surface detection toward the bandpass filter 68 of the surface detection unit 55.

[0131] In a modified version of the second embodiment, the second irradiation light Lb emitted from the second light source 60 of the surface detection unit 55 is incident on the diffractive optical element 163 of the surface detection deflection unit 161 via the second irradiation optical system 61, similar to the first embodiment. The second irradiation light Lb reflected by the diffractive optical element 163 is focused by the first relay lens 155 for surface detection. The second irradiation light Lb focused by the first relay lens 155 for surface detection passes through the second relay lens 156 for surface detection and is reflected by the second dichroic mirror 35. The second irradiation light Lb reflected by the second dichroic mirror 35 is irradiated by the objective optical system 15 toward the first observation area SC1 of the substrate WF and focused.

[0132] Furthermore, the second irradiation light Lb# emitted from the diffractive optical element 163 due to diffraction is focused by the first surface detection relay lens 155. The second irradiation light Lb# focused by the first surface detection relay lens 155 passes through the second surface detection relay lens 156 and is reflected by the second dichroic mirror 35. The second irradiation light Lb# reflected by the second dichroic mirror 35 due to diffraction is irradiated by the objective optical system 15 toward the second observation area SC2 of the substrate WF and focused. In this way, the surface of the substrate WF is irradiated with the second irradiation light Lb and the second irradiation light Lb# due to diffraction.

[0133] The second illumination light Lb reflected from the surface of the first observation area SC1 of the substrate WF is again incident on the objective optical system 15. The second illumination light Lb# diffracted and reflected from the surface of the second observation area SC2 of the substrate WF is also again incident on the objective optical system 15. The second illumination light Lb from the surface of the substrate WF and the second illumination light Lb# diffracted and incident on the objective optical system 15 are incident on the surface detection unit 55 via the second dichroic mirror 35 and the surface detection deflection unit 160. The second illumination light Lb from the surface of the substrate WF and the second illumination light Lb# diffracted and incident on the surface detection unit 55 are focused on the detection surface 79 of the second detector 78 via the second light receiving optical system 71, similar to the first embodiment.

[0134] On the detection surface 79 of the second detector 78, separate images are formed: one of the slit aperture 63a of the second irradiation light Lb reflected from the surface of the first observation area SC1 of the substrate WF, and another of the slit aperture 63a of the second irradiation light Lb# diffracted and reflected from the surface of the second observation area SC2 of the substrate WF. The second detector 78 receives the image of the slit aperture 63a of the second irradiation light Lb and the image of the slit aperture 63a of the second irradiation light Lb# diffracted and performs photoelectric conversion to output a second received signal.

[0135] As described above, the detection surface 79 of the second detector 78 separately forms an image of the slit aperture 63a of the second irradiation light Lb reflected from the surface of the first observation area SC1 of the substrate WF, and an image of the slit aperture 63a of the second irradiation light Lb# diffracted and reflected from the surface of the second observation area SC2 of the substrate WF. Therefore, the calculation unit 88 can determine, based on the second light-receiving signal output from the second detector 78, the imaging position of the image of the slit aperture 63a of the second irradiation light Lb on the surface of the first observation area SC1, and the imaging position of the image of the slit aperture 63a of the second irradiation light Lb# diffracted and reflected on the surface of the second observation area SC2, in the optical axis direction of the objective optical system 15. Furthermore, the calculation unit 88 can also determine, based on the second light-receiving signal output from the second detector 78, the position of the surface of the first observation area SC1 and the position of the surface of the second observation area SC2, in the optical axis direction of the objective optical system 15 or in a direction parallel to the optical axis direction.

[0136] As a result, the calculation unit 88 determines the position of the surface of the second observation area SC2 in a direction parallel to the optical axis direction of the objective optical system 15 based on the second light-receiving signal output from the second detector 78 during the first period, and determines a control signal for autofocus control during the second period, thereby achieving the same effect as in the second embodiment described above.

[0137] In the modified example described above, instead of the diffractive optical element 163, a reflective member and a diffractive optical element may be provided on the base portion 162. The reflective member reflects the second irradiation light Lb that has passed through the bandpass filter 68 of the surface detection unit 55 toward the first relay lens 155 for surface detection. The diffractive optical element is placed between the reflective member and the first relay lens 155 for surface detection, and the second irradiation light Lb reflected by the reflective member is incident on it. From the diffractive optical element, the second irradiation light that has passed through the diffractive member and the second irradiation light due to diffraction are emitted toward the first relay lens 155 for surface detection. The diffractive optical element may be constructed using a birefringent prism such as a Nicol prism, a Gran-Thomson prism, a Rochon prism, or a Wollaston prism. Alternatively, the diffractive optical element may be constructed using a thin film plate, a rotating wedge prism, or a transmissive diffraction grating.

[0138] [Third Embodiment] Next, a defect inspection apparatus according to the third embodiment will be described. The defect inspection apparatus according to the third embodiment has a configuration that is common to the defect inspection apparatus 1 according to the first embodiment, except for the arrangement of the surface detection unit. Therefore, the same reference numerals as in the first embodiment are used for components similar to those in the first embodiment, and detailed descriptions are omitted. As shown in Figure 13, the defect inspection apparatus 201 according to the third embodiment mainly consists of an inspection optical device 210 and an information processing device 90. The inspection optical device 210 and the information processing device 90 are configured to send and receive data from each other via a network cable NW. The inspection optical device 210 includes a stage 11 on which a substrate WF is placed, an objective optical system 15, a first light source unit 20, a first irradiation optical system 230, a first light receiving unit 40, a surface detection unit 255, and an optical device control unit 280.

[0139] The first illumination optical system 230 irradiates the substrate WF with the first illumination light La emitted from the first light source unit 20 via the objective optical system 15. The first illumination optical system 230 comprises, in order from the first light source unit 20 side, a first dichroic mirror 31, a second dichroic mirror 235, a deflection unit 32, a first relay lens 33, and a second relay lens 34. The first dichroic mirror 31, deflection unit 32, first relay lens 33, and second relay lens 34 have the same configuration as the first dichroic mirror 31, deflection unit 32, first relay lens 33, and second relay lens 34 of the first embodiment, and a detailed explanation is omitted.

[0140] The second dichroic mirror 235 has the characteristic of reflecting light in the green light wavelength range and transmitting light in the longer wavelength range and light in the shorter wavelength range than green light. The second dichroic mirror 235 is not limited to the wavelength characteristics described above, and it is sufficient if it has the characteristic of reflecting the second irradiation light Lb (and the reflected light Le described later) from the surface detection unit 255 and transmitting the first irradiation light La from the first dichroic mirror 31 and the detection light Ld from the deflection unit 32.

[0141] Furthermore, the deflection unit 32 of the third embodiment is capable of scanning the surface of the substrate WF with the second irradiation light Lb from the surface detection unit 255 in two directions, the X direction and the Y direction. Therefore, by swinging or rotating the X-direction deflection mirror 32a and the Y-direction deflection mirror 32b, the deflection unit 32 can move the irradiation area of ​​the second irradiation light Lb on the substrate WF in two directions (XY direction) and scan the surface of the substrate WF in two dimensions. In addition, the first light receiving optical system 41 of the first light receiving unit 40 in the third embodiment includes the second relay lens 34 of the first irradiation optical system 230, the first relay lens 33, the deflection unit 32, the second dichroic mirror 235, and the first dichroic mirror 31.

[0142] As shown in Figure 14, the surface detection unit 255 comprises a second light source 60, a second illumination optical system 61, and a second light receiving unit 70. Furthermore, the surface detection unit 255 includes a second dichroic mirror 235 of the first illumination optical system 230. The second light source 60, the second illumination optical system 61, and the second light receiving unit 70 have the same configuration as the second light source 60, the second illumination optical system 61, and the second light receiving unit 70 of the first embodiment, and a detailed explanation is omitted. In the third embodiment, the second illumination optical system 61 irradiates the surface of the substrate WF with the second illumination light Lb emitted from the second light source 60 via the deflection unit 32, the first relay lens 33, the second relay lens 34, and the objective optical system 15. In the third embodiment, the second light-receiving optical system 71 of the second light-receiving unit 70 receives reflected light Le from the surface of the substrate WF irradiated with the second irradiation light Lb via the objective optical system 15, the second relay lens 34, the first relay lens 33, and the deflection unit 32, and focuses it on the second detector 78.

[0143] The optical device control unit 280, like the optical device control unit 80 of the first embodiment, comprises an interface unit 281, a storage unit 285, a data acquisition unit 286, an image processing unit 287, and a calculation unit 288. Based on a control program stored in the storage unit 285, the optical device control unit 280 controls the operation of the stage moving unit 12, the first light source unit 20 (first light source 21), the deflection unit 32, the electric motor (not shown) of the magnification optical system 45, the surface detection unit 255 (second light source 60, lens moving unit 69), etc. The interface unit 281, storage unit 285, data acquisition unit 286, and image processing unit 287 have the same configuration as the interface unit 81, storage unit 85, data acquisition unit 86, and image processing unit 87 of the first embodiment, and a detailed explanation is omitted.

[0144] The calculation unit 288 determines the position (Z position) of the surface of the substrate WF in the optical axis direction of the objective optical system 15 or in a direction parallel to the optical axis direction, based on the second light-receiving signal output from the second detector 78, which is acquired by the data acquisition unit 286. In addition, similar to the first embodiment, the calculation unit 288 may determine the imaging position of the slit aperture 63a on the surface of the substrate WF (the focusing position of the second irradiating light Lb) based on the second light-receiving signal output from the second detector 78, and determine the control signal to be output to the stage movement unit 12 in autofocus control.

[0145] In the defect inspection apparatus 201 according to the third embodiment, when inspecting a substrate WF, setting information for the focusing position of the first irradiation light La and substrate configuration information transmitted from the interface unit 91 of the information processing apparatus 90 are input to the interface unit 281 of the inspection optical apparatus 210. The input setting information for the focusing position of the first irradiation light La and substrate configuration information are stored in the storage unit 285 of the optical apparatus control unit 280. The optical apparatus control unit 280 outputs a control signal to the stage moving unit 12, and the stage moving unit 12 moves the position of the stage 11 in the optical axis direction of the objective optical system 15 to an inspection position where the first irradiation light La is focused at a focusing position inside the substrate WF.

[0146] The inspection position of the stage 11 in the optical axis direction of the objective optical system 15 may be, for example, the position where the first illumination light La is focused at a focusing position inside the second layer LY2 in the substrate WF, as shown in Figure 15. Alternatively, the inspection position of the stage 11 in the optical axis direction of the objective optical system 15 may be the position where the first illumination light La is focused at a focusing position inside the third layer LY3 in the substrate WF. In the following description, as an example, we will describe the case where the first illumination light La is focused at a focusing position inside the second layer LY2 in the substrate WF.

[0147] The optical device control unit 280 may output a control signal for autofocus control to the stage moving unit 12, and the stage moving unit 12 may move the position of the stage 11 in the optical axis direction of the objective optical system 15 to the inspection position. In this case, the calculation unit 288 of the optical device control unit 280 may determine the control signal for autofocus control based on the second light receiving signal output from the second detector 78, similar to the first embodiment.

[0148] With the position of the stage 11 in the optical axis direction of the objective optical system 15 located at the inspection position described above, the calculation unit 288 of the optical device control unit 280 determines the position (Z position) of the surface of the substrate WF in the optical axis direction of the objective optical system 15 or in a direction parallel to the optical axis direction. At this time, the second irradiation light Lb emitted from the second light source 60 of the surface detection unit 255 is incident on the second dichroic mirror 235 via the second irradiation optical system 61, similar to the first embodiment. The second irradiation light Lb reflected by the second dichroic mirror 235 is incident on the deflection unit 32. The second irradiation light Lb incident on the deflection unit 32 is reflected in this order by the X-direction deflection mirror 32a and the Y-direction deflection mirror 32b, and is focused by the first relay lens 33. The second irradiation light Lb focused by the first relay lens 33 is transmitted through the second relay lens 34. The second illumination light Lb that has passed through the second relay lens 34 is focused and directed toward the substrate WF by the objective optical system 15.

[0149] When the second irradiation light Lb is irradiated onto the substrate WF, the deflection unit 32 scans the surface of the substrate WF with the second irradiation light Lb from the surface detection unit 255. The area scanned by the second irradiation light Lb from the surface detection unit 255 by the deflection unit 32 may be set to the same area scanned by the first irradiation light La from the first light source unit 20 (observation area). The optical device control unit 280 outputs a control signal to the stage moving unit 12, and while the position of the stage 11 in the optical axis direction of the objective optical system 15 remains at the inspection position described above, the stage 11 is moved in the X and Y directions, thereby irradiating the entire substrate WF with the second irradiation light Lb.

[0150] The second illumination light Lb, irradiated from the objective optical system 15 toward the substrate WF, is reflected by the surface of the substrate WF and enters the objective optical system 15 again. The reflected light Le (second illumination light Lb) from the surface of the substrate WF that enters the objective optical system 15 passes through the objective optical system 15 and is focused by the second relay lens 34. The reflected light Le focused by the second relay lens 34 passes through the first relay lens 33 and enters the deflection unit 32. The reflected light Le that enters the deflection unit 32 is reflected in this order by the Y-direction deflection mirror 32b and the X-direction deflection mirror 32a, and is reflected by the second dichroic mirror 235. The reflected light Le reflected by the second dichroic mirror 235 is focused on the detection surface 79 of the second detector 78 via the second light-receiving optical system 71 of the surface detection unit 255, similar to the first embodiment. The second detector 78 receives the image from the slit aperture 63a formed on the detection surface 79, performs photoelectric conversion, and outputs a second received signal.

[0151] The second light-receiving signal output from the second detector 78 is acquired by the data acquisition unit 286. Based on the second light-receiving signal acquired by the data acquisition unit 286, the calculation unit 288 determines the position (Z position) of the substrate WF surface in the direction of the optical axis of the objective optical system 15 or in a direction parallel to the optical axis. The position information regarding the position (Z position) of the substrate WF surface determined by the calculation unit 288 is stored in the storage unit 285.

[0152] Next, the optical device control unit 280 controls the first light source unit 20 (first light source 21) to irradiate the substrate WF with the first irradiation light La while the position of the stage 11 in the optical axis direction of the objective optical system 15 is in the inspection position described above. The laser light emitted from the first light source 21 under the control of the optical device control unit 280 is shaped by the light source lens 22 to become parallel light and is emitted from the first light source unit 20 as the first irradiation light La. The first irradiation light La emitted from the first light source unit 20 passes through the first dichroic mirror 31 and the second dichroic mirror 235 of the first irradiation optical system 230 and is incident on the deflection unit 32. The first irradiation light La incident on the deflection unit 32 is reflected in this order by the X-direction deflection mirror 32a and the Y-direction deflection mirror 32b and is incident on the first relay lens 33. The first illumination light La that has passed through the first relay lens 33 is focused onto the first intermediate image plane Im1 and incident on the second relay lens 34. The first illumination light La that has passed through the second relay lens 34 is irradiated toward the substrate WF by the objective optical system 15 and focused at a focal position set within the second layer LY2 of the substrate WF.

[0153] When the first irradiation light La is irradiated onto the substrate WF, the deflection unit 32 of the first irradiation optical system 230 scans the interior of the second layer LY2 in the substrate WF with the first irradiation light La from the first light source unit 20. After the deflection unit 32 scans the interior of the second layer LY2 in the observation area of ​​the substrate WF facing the objective optical system 15, the optical device control unit 280 outputs a control signal to the stage movement unit 12 to move the stage 11 in the X or Y direction. While the position of the stage 11 in the optical axis direction of the objective optical system 15 remains at the inspection position described above, the stage movement unit 12 moves the stage 11 in the X or Y direction, thereby displacing the observation area of ​​the substrate WF facing the objective optical system 15 in the X or Y direction.

[0154] The detection light Ld generated inside the second layer LY2 (irradiation region 25) of the substrate WF by multiphoton excitation with the first irradiation light La is incident on the objective optical system 15. The detection light Ld from the substrate WF incident on the objective optical system 15 passes through the objective optical system 15 and becomes parallel light, and is incident on the second relay lens 34. The detection light Ld that has passed through the second relay lens 34 is focused on the first intermediate image plane Im1 and is incident on the first relay lens 33. The detection light Ld that has passed through the first relay lens 33 becomes parallel light and is incident on the deflection section 32. The detection light Ld that has been incident on the deflection section 32 is reflected in this order by the Y-direction deflection mirror 32b and the X-direction deflection mirror 32a, and passes through the second dichroic mirror 235. The detection light Ld that has passed through the second dichroic mirror 235 is reflected by the first dichroic mirror 31.

[0155] The detection light Ld reflected by the first dichroic mirror 31 passes through the barrier filter 42 of the first light-receiving optical system 41 and enters the focusing lens 43. The detection light Ld that has passed through the focusing lens 43 is focused on the second intermediate image plane Im2 and enters the magnification optical system 45. The detection light Ld that has passed through the magnification optical system 45 is focused on the image plane Imp (detection surface 52 of the first detector 51) and forms an image 49 of the illuminated area 25 inside the second layer LY2 of the substrate WF. The first detector 51 receives the image 49 of the illuminated area 25 with multiple detection pixels 53, performs photoelectric conversion, and outputs a first light-receiving signal.

[0156] The first light-receiving signal output from the first detector 51 is acquired by the data acquisition unit 286. The image processing unit 287 generates image data of the cross-section of the second layer LY2 of the substrate WF in the XY direction (a direction perpendicular to the thickness direction of the substrate WF) based on the first light-receiving signal output from multiple detection pixels 53 of the first detector 51, which is acquired by the data acquisition unit 286. At this time, the image processing unit 287 uses position information regarding the position (Z position) of the surface of the substrate WF stored in the storage unit 285 to correct the depth position (Z position) of the cross-section of the second layer LY2 of the substrate WF from the surface of the substrate WF. As a result, even if the substrate WF is curved or tilted, image data of the cross-section of the second layer LY2 of the substrate WF in the XY direction can be generated with high accuracy by correcting the image data using position information regarding the position (Z position) of the surface of the substrate WF. Image data of the cross-section in the XY direction of the second layer LY2 of the substrate WF, generated by the image processing unit 287, is transmitted from the interface unit 281 to the information processing unit 90.

[0157] Image data of the cross-section in the XY direction of the second layer LY2 of the substrate WF, transmitted from the interface unit 281 of the inspection optical device 210 (optical device control unit 280), is input to the interface unit 91 of the information processing device 90. The image data of the cross-section in the XY direction of the second layer LY2 of the substrate WF input to the interface unit 91 is stored in the storage unit 95. The determination unit 96 determines whether or not there are defects inside the substrate WF based on the image data of the cross-section in the XY direction of the second layer LY2 of the substrate WF stored in the storage unit 95. The determination result of the determination unit 96 regarding the presence or absence of defects in the second layer LY2 of the substrate WF is stored in the storage unit 95.

[0158] [Characteristics of the Third Embodiment] According to the third embodiment, the image processing unit 287 generates image data of the cross-section in the XY direction inside the substrate WF based on position information regarding the position (Z position) of the surface of the substrate WF in the optical axis direction of the objective optical system 15 or in a direction parallel to the optical axis direction, and the first light-receiving signal from the first detector 51. As a result, even if the substrate WF is curved or tilted, the image data can be corrected using the position information regarding the position (Z position) of the surface of the substrate WF, thereby enabling the accurate generation of image data of the cross-section in the XY direction inside the substrate WF. Therefore, it becomes possible to improve the accuracy of inspection in defect inspection inside the substrate WF.

[0159] Furthermore, the first illumination optical system 230 has a deflection unit 32 that changes the direction of propagation of the first illumination light La to change the focusing position of the first illumination light La to a direction perpendicular to the optical axis AX of the objective optical system 15. The deflection unit 32 can also change the direction of propagation of the second illumination light Lb when the second illumination optical system 61 irradiates with the second illumination light Lb, thereby changing the irradiation area of ​​the second illumination light Lb to a direction perpendicular to the optical axis AX of the objective optical system 15. In this way, by sharing the deflection unit 32, the configuration of the second illumination optical system 61 (surface detection unit 255) can be simplified.

[0160] Furthermore, the information processing device 90 may be provided with a determination unit 96 that determines the presence or absence of defects inside the substrate WF based on image data of the inside of the substrate WF generated by the inspection optical device 210. As described above, since image data of the inside of the substrate WF can be generated with high accuracy, it becomes possible to improve the accuracy of inspection in defect inspection of the inside of the substrate WF. The determination unit 96 may also be provided in the optical device control unit 280 of the inspection optical device 210.

[0161] In the third embodiment described above, the setting information for the focusing position of the first irradiation light La may include a plurality of positions within the substrate WF where the optical axis position (Z position) of the objective optical system 15 is different. For example, the focusing position of the first irradiation light La may be set inside the second layer LY2 of the substrate WF and inside the third layer LY3 of the substrate WF. In this case, for a plurality of preset focusing positions of the first irradiation light La, the first irradiation optical system 230 irradiates with the first irradiation light La, the first light receiving unit 40 receives the light (detection light Ld) generated inside the substrate WF and outputs a first light receiving signal, and the image processing unit 287 generates image data of a plurality of cross-sections within the substrate WF where the optical axis position (Z position) of the objective optical system 15 is different. This makes it possible to acquire images of multiple cross-sections within the substrate WF where the objective optical system 15 is located at different positions in the optical axis direction (Z position), i.e., Z-stack images of the inside of the substrate WF.

[0162] In the third embodiment described above, the positional information relating to the position (Z position) of the substrate WF surface in the optical axis direction of the objective optical system 15 or in a direction parallel to the optical axis direction can also be said to be information relating to the surface irregularities of the substrate WF, that is, information relating to the topography of the substrate WF. Hereafter, information relating to the topography of the substrate WF will be referred to as substrate topography information. The substrate topography information is not limited to positional information relating to the position (Z position) of the substrate WF surface that can be detected using the surface detection unit 255, but may also be information relating to the surface shape of the substrate WF (the irregular shape of the surface of the substrate WF) that can be measured using a surface shape measuring device such as a Fizeau interferometer. Thus, the optical device control unit 280 may generate image data of a cross-section in the XY direction inside the substrate WF based on information relating to the surface shape of the substrate WF measured in advance using a surface shape measuring device and the first light receiving signal from the first detector 51.

[0163] In the third embodiment described above, the image processing unit 287 may use a deconvolution method to reconstruct the image of the inside of the substrate WF generated based on the first light-receiving signal from the first detector 51. In this case, the image processing unit 287 may perform deconvolution that takes into account the signal attenuation of the first light-receiving signal due to the aforementioned index mismatch aberration. The image processing unit 287 uses the substrate configuration information stored in the storage unit 285 (for example, information on the layer thickness in the thickness direction of multiple layers in the substrate WF and the refractive index of said multiple layers) to obtain an effective PSF (point image distribution function) that takes into account the index mismatch aberration, and by performing a more appropriate deconvolution, it becomes possible to generate image data of the inside of the substrate WF with improved resolution. The deconvolution technique is disclosed, for example, in the literature "Awoke Negash et al., Numerical approach for reducing out-of-focus light in bright-field fluorescence microscopy and superresolution speckle microscopy, Vol.36, No.12 / December 2019 / Journal of the Optical Society of America A, 2025" and "CLEMENS ROIDER et al., Deconvolution approach for 3D scanning microscopy with helical phase engineering, Vol.24, No.14 / 11 July 2016 / OPTICS EXPRESS, 15456".

[0164] [Fourth Embodiment] Next, a defect inspection apparatus according to the fourth embodiment will be described. The defect inspection apparatus according to the fourth embodiment has a configuration that is common to the defect inspection apparatus 1 according to the first embodiment, except for the arrangement of the surface detection unit. Therefore, for components that are the same as in the first embodiment, the same reference numerals are used as in the first embodiment and detailed descriptions are omitted. As shown in Figure 16, the defect inspection apparatus 301 according to the fourth embodiment mainly consists of an inspection optical device 310 and an information processing device 90. The inspection optical device 310 and the information processing device 90 are configured to send and receive data from each other via a network cable NW. The inspection optical device 310 includes a stage 11 on which a substrate WF is placed, an objective optical system 15, a first light source unit 20, a first irradiation optical system 330, a first light receiving unit 40, a surface detection unit 355, and an optical device control unit 380.

[0165] The first illumination optical system 330 irradiates the first illumination light La emitted from the first light source unit 20 toward the substrate WF via the objective optical system 15. The first illumination optical system 330 comprises, in order from the first light source unit 20 side, a dichroic mirror 331, a movable mirror 335, a deflection unit 32, a first relay lens 33, and a second relay lens 34. The deflection unit 32, the first relay lens 33, and the second relay lens 34 have the same configuration as the deflection unit 32, the first relay lens 33, and the second relay lens 34 of the first embodiment, and a detailed description is omitted. The dichroic mirror 331 has the same configuration as the first dichroic mirror 31 of the first embodiment, and a detailed description is omitted.

[0166] The movable mirror 335 is configured to move between a reflective position located in the optical path between the dichroic mirror 331 and the deflection unit 32 (see the solid line in Figure 16) and a non-reflective position located away from the optical path between the dichroic mirror 331 and the deflection unit 32 (see the dashed line in Figure 16). When the movable mirror 335 is in the reflective position, it reflects the second illumination light Lb from the surface detection unit 355 toward the deflection unit 32. When the movable mirror 335 is in the non-reflective position, the first illumination light La from the dichroic mirror 331 is incident on the deflection unit 32, and the detection light Ld from the deflection unit 32 is incident on the dichroic mirror 331.

[0167] In the fourth embodiment, the deflection unit 32 can scan the surface of the substrate WF with the second irradiation light Lb from the surface detection unit 355 in two directions, the X direction and the Y direction, when the movable mirror 335 is in the reflection position. Therefore, by swinging or rotating the X-direction deflection mirror 32a and the Y-direction deflection mirror 32b, the deflection unit 32 can move the irradiation area of ​​the second irradiation light Lb on the substrate WF in two directions (XY direction) and scan the surface of the substrate WF in two dimensions. Furthermore, the first light receiving optical system 41 in the first light receiving unit 40 of the fourth embodiment includes the second relay lens 34 of the first irradiation optical system 330, the first relay lens 33, the deflection unit 32, the movable mirror 335, and the dichroic mirror 331.

[0168] As shown in Figure 17, the surface detection unit 355 comprises a second light source 360, a second illumination optical system 61, and a second light receiving unit 70. Furthermore, the surface detection unit 355 includes a movable mirror 335 of the first illumination optical system 330. The second light source 360 ​​is configured similarly to the second light source 60 of the first embodiment. However, the wavelength of the second illumination light Lb is selected to be in a wavelength range (for example, the wavelength range of red light) in which a portion of the second illumination light Lb can pass through the surface of the substrate WF. The second illumination optical system 61 and the second light receiving unit 70 are configured similarly to the second illumination optical system 61 and the second light receiving unit 70 of the first embodiment, and a detailed explanation is omitted. In the fourth embodiment, the second illumination optical system 61 irradiates the second illumination light Lb emitted from the second light source 360 ​​toward the surface of the substrate WF via a deflection unit 32, a first relay lens 33, a second relay lens 34, and an objective optical system 15. In the fourth embodiment, the second light-receiving optical system 71 of the second light-receiving unit 70 receives the second irradiation light Lb reflected from the surface of the substrate WF or the interface of layers inside the substrate WF via the objective optical system 15, the second relay lens 34, the first relay lens 33, and the deflection unit 32, and focuses it on the second detector 78. The surface detection unit 355 of the fourth embodiment may also be called the substrate interface position detection unit.

[0169] The distance between the interface of the internal layers of the substrate WF and the objective optical system 15 is different from the distance between the surface of the substrate WF and the objective optical system 15. Therefore, on the detection surface 79 of the second detector 78, separate images are formed: one of the slit aperture 63a of the second illumination light Lb reflected from the surface of the substrate WF, and another of the slit aperture 63a of the second illumination light Lb reflected from the interface of the internal layers of the substrate WF. The second detector 78 receives both the image of the slit aperture 63a of the second illumination light Lb reflected from the surface of the substrate WF and the image of the slit aperture 63a of the second illumination light Lb reflected from the interface of the internal layers of the substrate WF, performs photoelectric conversion, and outputs a second received signal.

[0170] The optical device control unit 380, like the optical device control unit 80 of the first embodiment, comprises an interface unit 381, a storage unit 385, a data acquisition unit 386, an image processing unit 387, and a calculation unit 388. Based on a control program stored in the storage unit 385, the optical device control unit 380 controls the operation of the stage moving unit 12, the first light source unit 20 (first light source 21), the deflection unit 32, the electric motor (not shown) of the magnification optical system 45, the movable mirror 335, the surface detection unit 355 (second light source 360, lens moving unit 69), etc. The interface unit 381, the storage unit 385, the data acquisition unit 386, and the image processing unit 387 have the same configuration as the interface unit 81, the storage unit 85, the data acquisition unit 86, and the image processing unit 87 of the first embodiment, and a detailed explanation is omitted.

[0171] The calculation unit 388 determines the position (Z position) of the surface of the substrate WF and the position (Z position) of the interface between the layers inside the substrate WF, in the direction of the optical axis of the objective optical system 15 or in a direction parallel to the optical axis, based on the second light-receiving signal output from the second detector 78 acquired by the data acquisition unit 386. In addition, similar to the first embodiment, the calculation unit 388 may determine the imaging position of the slit aperture 63a on the surface of the substrate WF (the focusing position of the second irradiating light Lb) based on the second light-receiving signal output from the second detector 78, and determine the control signal to be output to the stage movement unit 12 in autofocus control.

[0172] As described above, the detection surface 79 of the second detector 78 separately forms images of the slit aperture 63a of the second irradiation light Lb reflected from the surface of the substrate WF and images of the slit aperture 63a of the second irradiation light Lb reflected from the interface of the layers inside the substrate WF. For example, as shown in Figure 19, the image of the slit aperture 63a of the second irradiation light Lb reflected from the surface of the substrate WF is formed at a first position K1 on the detection surface 79 of the second detector 78. A second received light signal (see the solid line in Figure 19) having a signal voltage J1 is output from each pixel corresponding to the first position K1 on the second detector 78. The horizontal axis of the graph shown in Figure 19 represents the longitudinal position K on the detection surface 79 of the second detector 78. The vertical axis of the graph shown in Figure 19 represents the signal voltage J of the second received light signal.

[0173] The image of the slit aperture 63a of the second irradiated light Lb reflected at the interface between the first layer LY1 and the second layer LY2 in the substrate WF is formed at a second position K2 on the detection surface 79 of the second detector 78, which is different from the first position K1. A second received signal (see the dashed line in Figure 19) with a signal voltage J2 is output from each pixel corresponding to the second position K2 in the second detector 78. The image of the slit aperture 63a of the second irradiated light Lb reflected at the interface between the second layer LY2 and the third layer LY3 in the substrate WF is formed at a third position K3 on the detection surface 79 of the second detector 78, which is different from the first position K1 and the second position K2. A second received signal (see the dashed line in Figure 19) with a signal voltage J3 is output from each pixel corresponding to the third position K3 in the second detector 78. Note that since a portion of the second irradiated light Lb passes through the surface of the substrate WF and reaches the interior of the substrate WF, the order J1 > J2 > J3.

[0174] Therefore, the calculation unit 388 can determine the position of the surface of the substrate WF and the position of the interface between the layers inside the substrate WF, in the direction of the optical axis of the objective optical system 15 or in a direction parallel to the optical axis, based on the second light-receiving signal output from the second detector 78. The calculation unit 388 can also determine the imaging position of the slit aperture 63a on the surface of the substrate WF, based on the second light-receiving signal output from the second detector 78.

[0175] In the defect inspection apparatus 301 according to the fourth embodiment, when inspecting a substrate WF, setting information for the focusing position of the first irradiation light La and substrate configuration information transmitted from the interface unit 91 of the information processing device 90 are input to the interface unit 381 of the inspection optical device 310. The input setting information for the focusing position of the first irradiation light La and substrate configuration information are stored in the storage unit 385 of the optical device control unit 380. The optical device control unit 380 outputs a control signal to the stage moving unit 12, and the stage moving unit 12 moves the position of the stage 11 in the optical axis direction of the objective optical system 15 to the inspection position where the first irradiation light La is focused at the focusing position inside the substrate WF. At the same time, the optical device control unit 380 also outputs a control signal to the movable mirror 335, and moves the movable mirror 335 to the aforementioned reflection position.

[0176] The inspection position of the stage 11 in the optical axis direction of the objective optical system 15 may be, for example, the position where the first illumination light La is focused at a focusing position inside the second layer LY2 in the substrate WF, as shown in Figure 18. Alternatively, the inspection position of the stage 11 in the optical axis direction of the objective optical system 15 may be the position where the first illumination light La is focused at a focusing position inside the third layer LY3 in the substrate WF. In the following description, as an example, we will describe the case where the first illumination light La is focused at a focusing position inside the second layer LY2 in the substrate WF.

[0177] The optical device control unit 380 may output a control signal for autofocus control to the stage moving unit 12, and the stage moving unit 12 may move the position of the stage 11 in the optical axis direction of the objective optical system 15 to the inspection position. In this case, the calculation unit 388 of the optical device control unit 380 may determine the control signal for autofocus control based on the second light receiving signal output from the second detector 78, similar to the first embodiment.

[0178] With the position of the stage 11 in the optical axis direction of the objective optical system 15 located at the inspection position described above, the calculation unit 388 of the optical device control unit 380 determines the position (Z position) of the surface of the substrate WF in the optical axis direction of the objective optical system 15 or in a direction parallel to the optical axis direction, and the position (Z position) of the interface between the first layer LY1 and the second layer LY2 on the substrate WF. At this time, the second irradiation light Lb emitted from the second light source 360 ​​of the surface detection unit 355 is incident on the movable mirror 335 via the second irradiation optical system 61, similar to the first embodiment. The second irradiation light Lb reflected by the movable mirror 335 is incident on the deflection unit 32. The second irradiation light Lb incident on the deflection unit 32 is reflected in this order by the X-direction deflection mirror 32a and the Y-direction deflection mirror 32b, and is focused by the first relay lens 33. The second irradiation light Lb focused by the first relay lens 33 is transmitted through the second relay lens 34. The second illumination light Lb that has passed through the second relay lens 34 is focused and directed toward the substrate WF by the objective optical system 15.

[0179] When the second irradiation light Lb is irradiated onto the substrate WF, the deflection unit 32 scans the surface of the substrate WF with the second irradiation light Lb from the surface detection unit 255. The area scanned by the second irradiation light Lb from the surface detection unit 255 by the deflection unit 32 may be set to the same area scanned by the first irradiation light La from the first light source unit 20 (observation area). The optical device control unit 380 outputs a control signal to the stage moving unit 12, and while the position of the stage 11 in the optical axis direction of the objective optical system 15 remains at the inspection position described above, the stage 11 is moved in the X and Y directions, thereby irradiating the entire substrate WF with the second irradiation light Lb.

[0180] A portion of the second illumination light Lb irradiated from the objective optical system 15 toward the substrate WF is reflected at the surface of the substrate WF and re-enters the objective optical system 15. Another portion of the second illumination light Lb irradiated from the objective optical system 15 toward the substrate WF passes through the surface of the substrate WF, is reflected at the interface between the first layer LY1 and the second layer LY2, and re-enters the objective optical system 15. Hereafter, the second illumination light Lb reflected at the surface of the substrate WF may be referred to as the first reflected light Le1, and the second illumination light Lb reflected at the interface between the first layer LY1 and the second layer LY2 in the substrate WF may be referred to as the second reflected light Le2. The first reflected light Le1 and the second reflected light Le2 from the substrate WF that are incident on the objective optical system 15 are transmitted through the objective optical system 15 and focused by the second relay lens 34. The first reflected light Le1 and the second reflected light Le2, focused by the second relay lens 34, pass through the first relay lens 33 and are incident on the deflection unit 32. The first reflected light Le1 and the second reflected light Le2 incident on the deflection unit 32 are reflected in this order by the Y-direction deflection mirror 32b and the X-direction deflection mirror 32a, and are reflected by the movable mirror 335. The first reflected light Le1 and the second reflected light Le2 reflected by the movable mirror 335 are focused on the detection surface 79 of the second detector 78 via the second light-receiving optical system 71 of the surface detection unit 355, similar to the first embodiment. The second detector 78 receives the image of the slit aperture 63a of the second irradiated light Lb reflected from the surface of the substrate WF and the image of the slit aperture 63a of the second irradiated light Lb reflected from the interface between the first layer LY1 and the second layer LY2 in the substrate WF, which are formed on the detection surface 79, performs photoelectric conversion, and outputs a second received signal.

[0181] The second light-receiving signal output from the second detector 78 is acquired by the data acquisition unit 386. Based on the second light-receiving signal acquired by the data acquisition unit 386, the calculation unit 388 determines the position (Z position) of the surface of the substrate WF in the direction of the optical axis of the objective optical system 15 or in a direction parallel to the optical axis, and the position (Z position) of the interface between the first layer LY1 and the second layer LY2 on the substrate WF. The position information regarding the position (Z position) of the surface of the substrate WF and the position information regarding the position (Z position) of the interface between the first layer LY1 and the second layer LY2 on the substrate WF, as determined by the calculation unit 388, are stored in the storage unit 385.

[0182] Next, the optical device control unit 380 controls the first light source unit 20 (first light source 21) to irradiate the substrate WF with the first irradiation light La while the position of the stage 11 in the optical axis direction of the objective optical system 15 is in the inspection position described above. At this time, the optical device control unit 380 also outputs a control signal to the movable mirror 335, moving the movable mirror 335 to the aforementioned non-reflective position. The laser light emitted from the first light source 21 under the control of the optical device control unit 380 is shaped into parallel light by the light source lens 22 and emitted from the first light source unit 20 as the first irradiation light La. The first irradiation light La emitted from the first light source unit 20 passes through the dichroic mirror 331 of the first irradiation optical system 330 and is incident on the deflection section 32. The first irradiation light La incident on the deflection section 32 is reflected in this order by the X-direction deflection mirror 32a and the Y-direction deflection mirror 32b and is incident on the first relay lens 33. The first illumination light La that has passed through the first relay lens 33 is focused onto the first intermediate image plane Im1 and incident on the second relay lens 34. The first illumination light La that has passed through the second relay lens 34 is irradiated toward the substrate WF by the objective optical system 15 and focused at a focal position set within the second layer LY2 of the substrate WF.

[0183] When the first irradiation light La is irradiated onto the substrate WF, the deflection unit 32 of the first irradiation optical system 330 scans the interior of the second layer LY2 in the substrate WF with the first irradiation light La from the first light source unit 20. After the deflection unit 32 scans the interior of the second layer LY2 in the observation area of ​​the substrate WF facing the objective optical system 15, the optical device control unit 380 outputs a control signal to the stage moving unit 12 to move the stage 11 in the X or Y direction. While the position of the stage 11 in the optical axis direction of the objective optical system 15 remains at the inspection position described above, the stage moving unit 12 moves the stage 11 in the X or Y direction, thereby displacing the observation area of ​​the substrate WF facing the objective optical system 15 in the X or Y direction.

[0184] The detection light Ld generated inside the second layer LY2 (irradiation region 25) of the substrate WF by multiphoton excitation with the first irradiation light La is incident on the objective optical system 15. The detection light Ld from the substrate WF that is incident on the objective optical system 15 passes through the objective optical system 15 and becomes parallel light, and is incident on the second relay lens 34. The detection light Ld that has passed through the second relay lens 34 is focused on the first intermediate image plane Im1 and is incident on the first relay lens 33. The detection light Ld that has passed through the first relay lens 33 becomes parallel light and is incident on the deflection section 32. The detection light Ld that is incident on the deflection section 32 is reflected in this order by the Y-direction deflection mirror 32b and the X-direction deflection mirror 32a, and is reflected by the dichroic mirror 331.

[0185] The detection light Ld reflected by the dichroic mirror 331 passes through the barrier filter 42 of the first light-receiving optical system 41 and enters the focusing lens 43. The detection light Ld that has passed through the focusing lens 43 is focused on the second intermediate image plane Im2 and enters the magnification optical system 45. The detection light Ld that has passed through the magnification optical system 45 is focused on the image plane Imp (detection surface 52 of the first detector 51) and forms an image 49 of the illuminated area 25 inside the second layer LY2 of the substrate WF. The first detector 51 receives the image 49 of the illuminated area 25 with multiple detection pixels 53, performs photoelectric conversion, and outputs a first light-receiving signal.

[0186] The first light-receiving signal output from the first detector 51 is acquired by the data acquisition unit 386. The image processing unit 387 generates image data of the cross-section of the second layer LY2 of the substrate WF in the XY direction (direction perpendicular to the thickness direction of the substrate WF) based on the first light-receiving signal output from multiple detection pixels 53 of the first detector 51, which is acquired by the data acquisition unit 386. At this time, the image processing unit 387 uses position information regarding the position of the surface of the substrate WF (Z position) and position information regarding the position of the interface between the first layer LY1 and the second layer LY2 of the substrate WF (Z position) stored in the storage unit 385 to correct the depth position (Z position) of the cross-section of the second layer LY2 of the substrate WF from the surface of the substrate WF. As a result, even if the substrate WF is curved or tilted, and there are variations in the thickness of each layer in the substrate WF, the image data can be corrected using positional information regarding the surface position (Z position) of the substrate WF and positional information regarding the interface position (Z position) between the first layer LY1 and the second layer LY2 in the substrate WF. This allows for the accurate generation of cross-sectional image data in the XY direction of the second layer LY2 of the substrate WF. The cross-sectional image data of the second layer LY2 of the substrate WF in the XY direction, generated by the image processing unit 387, is transmitted from the interface unit 381 to the information processing device 90.

[0187] Image data of the cross-section in the XY direction of the second layer LY2 of the substrate WF, transmitted from the interface unit 381 of the inspection optical device 310 (optical device control unit 380), is input to the interface unit 91 of the information processing device 90. The image data of the cross-section in the XY direction of the second layer LY2 of the substrate WF input to the interface unit 91 is stored in the storage unit 95. The determination unit 96 determines whether or not there is a defect in the second layer LY2 of the substrate WF based on the image data of the cross-section in the XY direction of the second layer LY2 of the substrate WF stored in the storage unit 95. The determination result of the determination unit 96 regarding the presence or absence of a defect in the second layer LY2 of the substrate WF is stored in the storage unit 95.

[0188] [Characteristic configuration of the fourth embodiment] According to the fourth embodiment, the image processing unit 387 generates image data of the cross-section in the XY direction of the second layer LY2 of the substrate WF based on position information relating to the position (Z position) of the surface of the substrate WF, position information relating to the position (Z position) of the interface between the first layer LY1 and the second layer LY2 of the substrate WF, and the first light-receiving signal from the first detector 51. As a result, even if the substrate WF is curved or tilted, and there are variations in the thickness of each layer in the substrate WF, the image data of the cross-section in the XY direction of the second layer LY2 of the substrate WF can be accurately generated by correcting the image data using the position information relating to the position (Z position) of the surface of the substrate WF and the position information relating to the interface between the first layer LY1 and the second layer LY2 of the substrate WF.

[0189] Furthermore, the image processing unit 387 can also generate image data of the cross-section in the XY direction of the third layer LY3 of the substrate WF, based on position information regarding the position (Z position) of the surface of the substrate WF, position information regarding the position (Z position) of the interface between the first layer LY1 and the second layer LY2 in the substrate WF, position information regarding the position (Z position) of the interface between the second layer LY2 and the third layer LY3 in the substrate WF, and a first light-receiving signal from the first detector 51, similar to the case of the second layer LY2 of the substrate WF. In this way, image data of the cross-section in the XY direction of at least one of the multiple layers of the substrate WF can be generated with high accuracy based on position information regarding the position of at least one interface among the multiple layers of the substrate WF and a first light-receiving signal from the first detector 51. Therefore, it becomes possible to improve the accuracy of inspection in defect inspection inside the substrate WF.

[0190] Furthermore, the first illumination optical system 330 has a deflection unit 32 that changes the direction of propagation of the first illumination light La to change the focusing position of the first illumination light La to a direction perpendicular to the optical axis AX of the objective optical system 15. The deflection unit 32 can also change the direction of propagation of the second illumination light Lb when the second illumination optical system 61 irradiates with the second illumination light Lb, thereby changing the irradiation area of ​​the second illumination light Lb to a direction perpendicular to the optical axis AX of the objective optical system 15. In this way, by sharing the deflection unit 32, the configuration of the second illumination optical system 61 (surface detection unit 355) can be simplified.

[0191] Furthermore, the information processing device 90 may be provided with a determination unit 96 that determines the presence or absence of defects inside the substrate WF based on image data of the inside of the substrate WF generated by the inspection optical device 310. As described above, since image data of the inside of the substrate WF can be generated with high accuracy, it becomes possible to improve the accuracy of inspection in defect inspection of the inside of the substrate WF. The determination unit 96 may also be provided in the optical device control unit 380 of the inspection optical device 310.

[0192] In the fourth embodiment described above, the setting information for the focusing position of the first irradiation light La may include a plurality of positions within the substrate WF where the optical axis position (Z position) of the objective optical system 15 is different. For example, the focusing position of the first irradiation light La may be set inside the second layer LY2 of the substrate WF and inside the third layer LY3 of the substrate WF. In this case, for a plurality of preset focusing positions of the first irradiation light La, the first irradiation optical system 330 irradiates with the first irradiation light La, the first light receiving unit 40 receives the light (detection light Ld) generated inside the substrate WF and outputs a first light receiving signal, and the image processing unit 387 generates image data of a plurality of cross-sections within the substrate WF where the optical axis position (Z position) of the objective optical system 15 is different. This makes it possible to acquire images of multiple cross-sections within the substrate WF where the objective optical system 15 is located at different positions in the optical axis direction (Z position), i.e., Z-stack images of the inside of the substrate WF.

[0193] In the fourth embodiment described above, the image processing unit 387 may, similar to the third embodiment, use a deconvolution method to reconstruct the image inside the substrate WF generated based on the first light-receiving signal from the first detector 51. In this case, the image processing unit 387 may perform deconvolution that takes into account the signal attenuation of the first light-receiving signal due to the aforementioned index mismatch aberration. The image processing unit 387 can use the substrate configuration information stored in the storage unit 385 to obtain an effective PSF (point image distribution function) that takes into account the index mismatch aberration, and by performing more appropriate deconvolution, it becomes possible to generate image data inside the substrate WF with improved resolution.

[0194] In the fourth embodiment described above, a movable mirror 335 is provided in the optical path between the dichroic mirror 331 and the deflection unit 32, but the embodiment is not limited to this. For example, instead of the movable mirror 335, a half-mirror may be provided in the optical path between the dichroic mirror 331 and the deflection unit 32 (the reflection position described above).

[0195] [Manufacturing method for circuit boards] Next, the manufacturing method of the substrate WF will be described. As shown in Figure 20, first, the substrate WF is prepared (step ST1). The GaN substrate WF is prepared using methods disclosed in, for example, the literature "Lung-Hsing Hsu et al., Development of GaN HEMTs Fabricated on Silicon, Silicon-on-Insulator, and Engineered Substrates and the Heterogeneous Integration, Micromachines, 2021, 12, 1159" and "Jiaqi He et al., Recent Advances in GaN-Based Power HEMT Devices, Advanced Electronic Materials, 2021, 7, 2001045".

[0196] Next, the substrate WF created in step ST1 is inspected (step ST2). At this time, one of the defect inspection devices from the first to fourth embodiments is used to inspect for defects inside the substrate WF. In addition, multiple types of defect inspection devices from the first to fourth embodiments may be used to inspect for defects inside the substrate WF. Thus, it is possible to inspect for defects inside the substrate WF using at least one defect inspection device from the first to fourth embodiments.

[0197] Then, feedback is provided regarding the inspection results of the substrate WF performed in step ST2 (step ST3). At this time, based on the inspection results of the substrate WF, for example, the manufacturing parameters used when creating the substrate WF in step ST1 may be changed. This method of manufacturing substrate WF makes it possible to improve the accuracy of inspections for defects inside the substrate WF.

[0198] In each of the embodiments described above, the stage moving unit 12 moves the stage 11 in the Z direction (in the direction of the optical axis of the objective optical system 15), thereby changing the relative position of the objective optical system 15 with respect to the substrate WF in the Z direction, but the system is not limited to this. For example, an optical system moving unit (not shown) that moves the objective optical system 15 in the Z direction may be provided. In this case, the stage moving unit 12 may not have the function of moving the stage 11 in the Z direction, and the optical system moving unit may move the objective optical system 15 in the Z direction, thereby changing the relative position of the objective optical system 15 with respect to the substrate WF in the Z direction. Alternatively, the stage moving unit 12 may move the stage 11 in the Z direction, and the optical system moving unit may move the objective optical system 15 in the Z direction, thereby changing the relative position of the objective optical system 15 with respect to the substrate WF in the Z direction. In this way, the system may be configured to move at least one of the focusing position of the first irradiated light La in the optical axis direction of the objective optical system 15 and the position of the substrate WF.

[0199] In each of the embodiments described above, the first light source unit 20 is provided in a manner that allows it to be attached to and replaced by the inspection optical device, but it is not limited to this, and may be provided separately from the inspection optical device.

[0200] In each of the embodiments described above, the second light-receiving unit 70 (second light-receiving optical system 71) receives the second illumination light Lb reflected from the surface of the substrate WF via the objective optical system 15, but it is not limited to this. For example, the second light-receiving unit may be provided near the objective optical system 15 so as to receive the second illumination light Lb reflected from the surface of the substrate WF without going through the objective optical system 15.

[0201] In each of the embodiments described above, a surface detection unit is provided in the inspection optical device of the defect inspection device. However, instead of this configuration, or in addition to this configuration, the surface detection unit may be provided in a device other than the defect inspection device. In this case, information regarding the surface shape (topography) of the substrate WF acquired by the surface detection unit outside the defect inspection device may be transmitted to the defect inspection device. For example, if the surface shape of the substrate WF is measured in advance while it is held in a substrate holder, and the substrate holder is then transported to the defect inspection device, information regarding the height distribution of the substrate WF in the Z direction with respect to a reference position on the substrate holder may be transmitted to the defect inspection device. In this case, by measuring the height in the Z direction of the reference position on the substrate holder in the defect inspection device, the height distribution of the substrate WF in the Z direction within the coordinate system of the defect inspection device can be obtained. Note that the reference position is not limited to the substrate holder, but may be set on the substrate WF.

[0202] In each of the embodiments described above, the substrate configuration information and the setting information for the focusing position of the first irradiation light La are input to the interface unit of the optical device control unit, but are not limited to this. For example, a user-operable input unit may be connected to the optical device control unit, and the substrate configuration information and the setting information for the focusing position of the first irradiation light La may be input to the input unit. The input unit may be configured using at least one of the following: a mouse, keyboard, touchpad, trackball, etc.

[0203] In the embodiments described above, a substrate used in the manufacture of power devices is given as an example of a substrate WF, but it is not limited to this. The substrate WF may be a substrate used in the manufacture of high-frequency devices, for example, a substrate on which a layer made of GaN is formed on a base substrate made of SiC. The substrate WF may be a substrate used in the manufacture of LEDs, for example, a substrate on which a layer made of GaN is formed on a base substrate made of sapphire. The substrate WF may be a substrate used in the manufacture of LDs (Laser Diodes), for example, a substrate on which a layer made of GaN is formed on a base substrate made of GaN. Furthermore, the substrate WF may have a layer made of SiC formed on a base substrate made of SiC. The substrate WF may be formed using gallium oxide (Ga2O3) or diamond.

[0204] At least some of the constituent elements of each embodiment described above can be appropriately combined with at least some other constituent elements of each embodiment described above. Some of the constituent elements of each embodiment described above may not be used.

[0205] The present invention is not limited to the embodiments described above, and can be modified as appropriate without contradicting the gist or idea of ​​the invention as can be read from the claims and the specification as a whole. Inspection optical devices, defect inspection devices, and substrate manufacturing methods that involve such modifications are also included in the technical scope of the present invention. [Explanation of Symbols]

[0206] 1. Defect Inspection Apparatus (First Embodiment) 10. Optical devices for inspection 11 Stage 15 Objective Optics 20 First light source unit 30 First illumination optical system 40 1st light receiving section 55 Surface detection unit 60 Second light source 61 Second irradiation optical system 70 2nd light receiving section 80 Optical device control unit 81 Interface section 85 Storage section 87 Image processing unit 88 Calculation unit 90 Information Processing Equipment 96 Judgment section 150 Surface detection deflection unit (second embodiment) 160 Surface detection deflection unit (modified version) 201 Defect Inspection Device (Third Embodiment) 210 Inspection Optical Devices 230 First irradiation optical system 255 Surface detection unit 280 Optical device control unit 281 Interface section 285 Storage section 287 Image processing unit 288 Calculation unit 301 Defect Inspection Device (Fourth Embodiment) 310 Inspection Optical Devices 330 First irradiation optical system 355 Surface detection unit (substrate interface position detection unit) 380 Optical device control unit 381 Interface section 385 Storage section 387 Image processing unit 388 Calculation unit WF board

Claims

1. In an inspection optical device used in a defect inspection device for inspecting defects in a circuit board, A first irradiation optical system that irradiates the substrate with a first irradiation light through an objective optical system, A first light receiving unit receives light generated inside the substrate by multiphoton excitation caused by the first irradiation light irradiated onto the substrate via the objective optical system and outputs a first light receiving signal, A processing unit that generates information about the inside of the substrate based on the first light-receiving signal from the first light-receiving unit, A second irradiation optical system that irradiates the substrate with a second irradiation light through the objective optical system, A second light receiving unit receives reflected light from the surface of the substrate irradiated with the second light and outputs a second light receiving signal, An inspection optical apparatus comprising a control unit that outputs a control signal to a moving unit that moves at least one of the focusing position of the first irradiated light in the optical axis direction and the position of the substrate, based on substrate configuration information relating to the configuration of the substrate and the second light receiving signal, to control the positional relationship between the focusing position of the first irradiated light in the optical axis direction and the position of the substrate in the optical axis direction.

2. The inspection optical apparatus according to claim 1, wherein the control unit outputs the control signal to the moving unit based on the substrate configuration information, the second light receiving signal, and setting information for the focusing position of the first irradiated light on the surface of the substrate in the optical axis direction.

3. The inspection optical apparatus according to claim 1, wherein the substrate configuration information includes information on a plurality of layers stacked in the thickness direction of the substrate.

4. The inspection optical apparatus according to claim 3, wherein the substrate configuration information includes information regarding the layer thickness of the plurality of layers in the thickness direction and the refractive index of the plurality of layers.

5. The inspection optical apparatus according to claim 4, wherein the control unit outputs the control signal to the moving unit based on the substrate configuration information, the second light receiving signal, setting information for the focusing position of the first irradiated light on the surface of the substrate in the optical axis direction, and information for the opening angle of the first irradiated light from the objective optical system toward the substrate.

6. The inspection optical apparatus according to claim 5, wherein the control unit outputs a control signal capable of correcting an aberration represented by the following formula to the moving unit. [Math 1] However, Wi(kp): Aberrations occurring in each of the plurality of layers located between the focusing position of the first irradiated light and the surface of the substrate. λ: Wavelength of the first irradiation light di: Layer thickness of each layer located between the focusing position of the first irradiated light and the surface of the substrate. ni: Refractive index of each layer located between the focusing position of the first irradiated light and the surface of the substrate.

7. The inspection optical apparatus according to claim 1, wherein the control unit comprises an input unit into which the substrate configuration information is input, and a storage unit for storing the substrate configuration information input to the input unit.

8. The inspection optical apparatus according to claim 7, wherein the control unit comprises a calculation unit that calculates the control signal to be output to the moving unit using the substrate configuration information.

9. The inspection optical apparatus according to claim 1, wherein the first irradiation light irradiated from the objective optical system toward the substrate is pulsed light having a pulse width of less than 1 picosecond.

10. The inspection optical apparatus according to claim 1, wherein the first irradiation light generates multiphoton excitation inside the substrate.

11. The inspection optical apparatus according to claim 10, wherein the first light-receiving unit receives light generated by the multiphoton excitation inside the substrate.

12. The first irradiation optical system is supplied with the first irradiation light from the light source, The inspection optical apparatus according to claim 1, wherein the control unit controls the light source to irradiate the substrate with the first irradiation light when the focusing position of the first irradiation light in the optical axis direction of the objective optical system is inside the substrate.

13. In an inspection optical device used in a defect inspection device for inspecting defects in a circuit board, An illumination optical system that irradiates the substrate with light from a light source via an objective optical system, A light receiving unit receives light generated inside the substrate by multiphoton excitation caused by the irradiation light irradiated onto the substrate via the objective optical system and outputs a received light signal. A processing unit that generates information about the inside of the substrate based on the light-receiving signal from the light-receiving unit, An inspection optical apparatus comprising: a control unit that controls the light source to irradiate the substrate with the irradiation light when the focusing position of the irradiation light in the optical axis direction of the objective optical system is inside the substrate.

14. The inspection optical apparatus according to claim 13, wherein the control unit controls the light source to restrict the irradiation of the light directed toward the substrate when the focusing position of the irradiation light in the optical axis direction of the objective optical system is not inside the substrate.

15. In an inspection optical device used in a defect inspection device for inspecting defects in a circuit board, An illumination optical system that irradiates the substrate with light from a light source via an objective optical system, A light receiving unit receives light generated inside the substrate by multiphoton excitation caused by the irradiation light irradiated onto the substrate via the objective optical system and outputs a received light signal. A processing unit that generates information about the inside of the substrate based on the light-receiving signal from the light-receiving unit, An inspection optical apparatus comprising: a control unit that controls the light source to restrict the irradiation of the light source toward the substrate when the focusing position of the irradiation light in the optical axis direction of the objective optical system is not inside the substrate; and a control unit that controls the light source to restrict the irradiation of the light toward the substrate.

16. In an inspection optical device used in a defect inspection device for inspecting defects in a circuit board, An illumination optical system that irradiates light toward the substrate via an objective optical system, A light receiving unit receives light generated inside the substrate by multiphoton excitation caused by the irradiation light irradiated onto the substrate via the objective optical system and outputs a received light signal. An inspection optical apparatus comprising a processing unit that generates information about the interior of the substrate based on substrate topography information relating to the topography of the substrate and the light-receiving signal from the light-receiving unit.

17. In an inspection optical device used in a defect inspection device for inspecting defects in a circuit board, An illumination optical system that irradiates the substrate with a first irradiation light through an objective optical system, A light receiving unit receives light generated inside the substrate by multiphoton excitation caused by the first irradiation light irradiated onto the substrate via the objective optical system and outputs a received light signal, A processing unit that generates information about the inside of the substrate based on the light-receiving signal from the light-receiving unit, A substrate surface position detection unit irradiates the surface of the substrate with a second irradiation light and receives the second irradiation light reflected from the surface of the substrate to detect the position of the surface of the substrate in the direction of the optical axis of the objective optical system or in a direction parallel to the optical axis; The system includes a control unit that outputs a control signal to a moving unit that moves at least one of the focusing position of the first irradiated light and the position of the substrate in the optical axis direction, thereby controlling the positional relationship between the focusing position of the first irradiated light and the position of the substrate in the optical axis direction, The aforementioned inspection optical device is, The first irradiation light is irradiated onto a first region, which is a part of the substrate, and the light generated inside the substrate by the first irradiation light irradiated onto the first region of the substrate is received by the light receiving unit, thereby generating information about the inside of the first region as first information. The first irradiation light is irradiated onto a second region of the substrate that is different from the first region, and the light generated inside the substrate by the first irradiation light irradiated onto the second region of the substrate is received by the light receiving unit, thereby generating information about the inside of the second region as second information. The substrate surface position detection unit, during the first period in which the first irradiation light is irradiated onto the first region, irradiates the surface of the second region of the substrate with the second irradiation light and receives the second irradiation light reflected from the surface of the second region to detect the position of the surface of the second region in the direction of the optical axis of the objective optical system or in a direction parallel to the optical axis. The control unit generates a control signal that controls the positional relationship between the focusing position of the first irradiation light in the optical axis direction and the position of the substrate during a second period in which the first irradiation light is irradiated onto the second region, based on the detection result of the position of the surface of the second region.

18. When the irradiation optical system is designated as the first irradiation optical system, the received light signal as the first received light signal, and the light receiving unit as the first light receiving unit, The substrate surface position detection unit is A second irradiation optical system that irradiates the surface of the substrate with the second irradiation light via the objective optical system, The system includes a second light receiving unit that receives the second irradiation light reflected from the surface of the substrate and outputs a second light receiving signal corresponding to the position on the surface of the substrate, During the first period, the second irradiation optical system irradiates the surface of the second region of the substrate with the second irradiation light via the objective optical system, and the second light receiving unit receives the second irradiation light reflected from the surface of the second region and outputs a second light receiving signal corresponding to the position on the surface of the second region. The inspection optical apparatus according to claim 17, wherein the control unit generates the control signal for the second period based on the second light receiving signal corresponding to the position of the surface of the second region.

19. In an inspection optical device used in a defect inspection device for inspecting defects in a substrate having multiple layers stacked in the thickness direction, An illumination optical system that irradiates the substrate with a first irradiation light through an objective optical system, A light receiving unit receives light generated within at least one of the plurality of layers of the substrate by multiphoton excitation by the first irradiation light irradiated toward the substrate, via the objective optical system, and outputs a received light signal. A substrate interface position detection unit detects the position of the interface of the substrate in the direction of the optical axis of the objective optical system or in a direction parallel to the optical axis, by irradiating a second irradiation light onto at least one interface among the interfaces of the plurality of layers of the substrate and receiving the second irradiation light reflected from the interface, An inspection optical apparatus comprising a processing unit that generates information about the interior of at least one layer of the substrate based on positional information relating to the position of the interface of the substrate and the light-receiving signal from the light-receiving unit.

20. In a defect inspection device for inspecting defects in a circuit board, The inspection optical device comprises the one described in any one of claims 1 to 19, A defect inspection device that inspects defects in a substrate based on the information about the substrate's interior generated by the optical inspection device.

21. Creating a circuit board, A method for manufacturing a substrate, comprising inspecting the manufactured substrate using the defect inspection apparatus described in claim 20.

22. A method for manufacturing a substrate according to claim 21, comprising changing the manufacturing parameters when manufacturing the substrate based on the inspection results of the substrate.

Images