Inspection device and inspection method

Abstract

To provide an inspection device and an inspection method capable of improving throughput of inspection.SOLUTION: An inspection device 1 includes: a polarization separation element 25 for separating first linearly polarized light whose vibration direction is a first direction in illumination light L1 including the first linearly polarized light, into second linearly polarized light and third linearly polarized light perpendicular to each other; an objective lens 15 for condensing the separated illumination light L2 on a sample SMP, and condensing reflected light R1 reflected by the sample SMP; an optical separation member HM2 for separating the reflected light R1 into reflected light R2 and reflected light R3; a polarized light separation member 22 for separating reflected light R4 including each polarization component; a polarized light separation member 23 for separating the reflected light R3 into reflected light R5 and reflected light R6; a light-receiving element 31 for receiving the reflected light R4; a light-receiving element 32 for receiving the reflected light R5; and a light-receiving element 33 for receiving the reflected light R6.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to an inspection device and an inspection method. [Background technology]

[0002] Compound semiconductors such as SiC and GaN, and piezoelectric crystal wafers such as LiNbO3 and LiTaO3 are manufactured in a bonded structure and a multi-layered structure. Inspection of wafers with such structures requires a technology to non-destructively and quickly inspect and evaluate crystal defects including scratches, foreign objects, voids, and uneven film thickness.

[0003] Common non-destructive methods include differential interference contrast for inspection of scratches on the nanometer order, bright field observation for inspection of foreign bodies and voids, and optical film thickness measurement methods (white light interference, reflectance spectroscopy, ellipsometry, etc.) for inspection of film thickness unevenness. However, when inspecting bonded wafers with films, the applicable inspection conditions differ depending on the method, so it is necessary to switch the inspection optical system. Therefore, it is difficult to simultaneously inspect and measure crystal defects, foreign bodies / voids, film thickness unevenness, etc. at high speed.

[0004] Fig. 1 is a diagram illustrating an example of a target defect in a bonded wafer, and Fig. 2 is a diagram illustrating an example of an inspection method and conditions for the target defect in a bonded wafer.

[0005] As shown in Figures 1 and 2, to inspect for crystal defects such as scratches, pits, and bumps, and for particles, a differential interference method using white light (broadband light) may be used. This makes it possible to suppress the contrast of internal interference that occurs within the film or laminated layer, and to inspect for crystal defects such as scratches and pits.

[0006] To inspect for voids, a bright-field observation method using white light may be used. If the light receiving element combines the light receiving signals of all wavelengths contained in the white light, the contrast of internal interference around the voids that occurs with monochromatic light (narrowband light) can be suppressed, and the voids can be inspected using the bright-field contrast of white light.

[0007] To inspect the wafer for unevenness in thickness, bright-field observation using monochromatic light may be used, which allows inspection of unevenness in thickness by contrast caused by interference within the film.

[0008] Fig. 3 is a diagram illustrating a target defect in a hetero epitaxial wafer, and Fig. 4 is a diagram illustrating an example of an inspection method and conditions for the target defect in a hetero epitaxial wafer.

[0009] As shown in Figures 3 and 4, in the case of hetero epitaxial wafers, the inspection method and example conditions vary depending on the object to be inspected, just as in the case of bonded wafers. To inspect hexagonal bumps, cracks, and slips, a differential interference method using white light (broadband light) may be used. To inspect particles and V-shaped V-pits, a bright-field observation method using white light may be used. In particular, when the substrate is a transparent body such as sapphire, it is also necessary to eliminate backside reflection.

[0010] As described above, it is not possible to detect many types of defects unless inspection wavelength bands and different optical principles are switched and combined.

[0011] Conventional methods for inspecting samples such as wafers include, for example, (1) reflectance spectroscopy, (2) differential interference contrast observation, (3) white light interference fringe scanning, (4) bright-field observation, and (5) confocal microscopy. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] JP 2001-021810 A [Patent Document 2] JP 2005-173580 A [Patent Document 3] JP 2011-118427 A [Patent Document 4] JP 2013-068738 A [Patent Document 5] JP 2014-235408 A [Patent Document 6] JP 2016-048400 A [Patent Document 7] JP 2013-217703 A Summary of the Invention [Problem to be solved by the invention]

[0013] Each of the above methods has its own problems.

[0014] (1) Reflectance spectroscopy The reflectance spectroscopy method measures the spectrum by splitting the reflected light from a sample illuminated with white light. The peak-valley method (PV method) is a method of analyzing film thickness by determining the wavelengths corresponding to the maximum and minimum reflectance from the spectrum. When using visible light, the PV method cannot be applied to film thicknesses less than the wavelength (approximately 0.5 μm) because the maximum and minimum spectrum patterns cannot be obtained. In addition, the spectrum can be theoretically calculated in the form of the wavelength dependence of absolute reflectance under conditions determined by the wavelength of light, film thickness, refractive index (n) and extinction coefficient (k) of the film and substrate. Therefore, the curve fit method determines the film thickness by parameter fitting the theoretical reflectance to the measurement data. In general, analysis can be applied from a few nm to a few μm, but a sufficient number of measurement wavelengths must be sampled for the film thickness.

[0015] A typical spectrometer cannot measure the spatial distribution of film thickness with high resolution, and only measures the average value of the area illuminated by the light. If there is a film thickness distribution (variation) within the illuminated area, the reflectance is averaged, making it impossible to obtain an accurate absolute reflectance. Furthermore, in general, imaging the absolute reflectance or film thickness distribution requires measurements at multiple points, which is not applicable to high-speed inspection.

[0016] (2) Differential interference observation method The differential interference contrast observation method (DIC) can add contrast to nano-order pits and scratches on the surface. In addition to an analyzer and polarizer, this method uses a Nomarski prism. The Nomarski prism splits the light used to observe the surface into "ordinary light" and "extraordinary light" (referred to here as such for convenience) into two lights (with polarization directions perpendicular to each other) separated in the sample surface direction by the shear amount. Therefore, by making these interfere with each other using an analyzer, it is possible to create a contrast corresponding to the phase difference between two points separated by the shear amount. This makes it possible to detect defects.

[0017] If the sample has a film structure or polarization characteristics, the contrast caused by these will complicate the differential interference contrast. This may prevent proper defect inspection. In addition, if there is a difference in reflectance of the sample itself or a material boundary, it will be difficult to distinguish this from the phase contrast caused by unevenness. Since only interference contrast and interference color can be observed, if you want to distinguish the original color and brightness of the sample, you need to remove the analyzer and polarizer from the light path. However, this bright-field image is a double image of "normal light" and "extraordinary light," so it cannot be used for inspection. To perform normal bright-field observation, the Nomarski prism must also be removed from the light path. Therefore, it is difficult to perform other observation methods at the same time.

[0018] (3) White light interference fringe scanning method The white light interference fringe scanning method can calculate the height by calculating the maximum intensity position of the white light interference fringe by Z-scanning the sample or objective lens. To measure the film thickness, it is necessary to separate and measure the interference intensity signals from the underlying substrate and the film surface. However, when the film thickness is 1 μm or less, it becomes difficult to separate these intensity signals. Furthermore, when a transparent film with low reflectivity exists on a substrate with high reflectivity, it is not possible to precisely measure the interference intensity from the transparent film, making film thickness measurement even more difficult. It is difficult to deal with multi-layer films, etc.

[0019] In optical interferometry, what is observed is interference color and interference contrast, so the original color and brightness of the sample cannot be determined as in bright-field observation. Also, white light interferometry cannot be achieved with monochromatic (narrow-band light).

[0020] (4) Bright-field observation method Bright-field observation can be performed with a general reflection-type optical microscope, and allows easy inspection of the original color and relative reflection intensity of the sample. However, since the resolution in the height direction is extremely poor, it is not possible to determine the uneven shape. When observing a film structure, the contrast observed varies depending on the combination of film thickness and wavelength. Therefore, by selecting the optimal single color, the optimal contrast change corresponding to the unevenness in film thickness can be obtained. When observing with white light, the contrast of each wavelength overlaps depending on the film structure, resulting in a complex color change pattern. Therefore, it is not easy to associate the contrast with the unevenness in film thickness.

[0021] (5) Confocal microscopy Height and film thickness measurements using a confocal microscope involve changing the distance between the objective lens and the sample by Z-scanning to detect the focal point. When the film thickness is less than a few microns, it is not possible to separate the reflected signals from the underlying substrate and the film surface, making film thickness measurement impossible. The signal separation limit depends heavily on the numerical aperture of the objective lens, so the film thickness measurement limit is significantly worse, at a few microns at high magnification and tens of microns at low magnification with a wide field of view. This means that nano-order irregularities cannot be inspected. When the film thickness is several tens of microns, the reflected light from the substrate and the film surface is separated, making it difficult for interference within the film to occur. On the other hand, when a transparent substrate is used, it is possible to separate the reflection from the back surface of the substrate from the inspection signal.

[0022] As described above, each of the above methods has its own problems.

[0023] In the prior art document, the device of Patent Document 1 uses a differential interference microscope and can calculate the phase difference and phase gradient from multiple wavelengths, but cannot simultaneously perform bright field observation. Also, it cannot avoid the problem of intra-film interference that occurs in film-attached bonded wafers, etc.

[0024] In addition, for example, in Patent Documents 2-6, the laser microscope and the differential interference microscope can switch between confocal laser observation and differential interference, and white non-confocal observation and differential interference by inserting and removing optical components, but cannot perform simultaneous observation. Bright field observation cannot be performed with a Nomarski prism attached.

[0025] Furthermore, for example, in Patent Document 7, in order to distinguish the contrast between large foreign bodies and nano-order crystal defects using a differential interference microscope, it is necessary to switch between bright field and dark field differential interference observation. In this case, there is a problem that the throughput of the inspection decreases. Therefore, by simultaneously detecting two mutually orthogonal differential interference contrasts (with inverted phases), two differential interference contrast images (DIC+ and DIC-) are obtained. By adding these, a bright field image with the interference terms canceled can be obtained. However, in the differential interference method, the light is separated in the direction of the measurement surface by the shear amount by the Nomarski prism, so there is a problem that the image becomes double or averaged depending on the relationship between the shear amount and the size of the inspection object.

[0026] Thus, when inspecting for crystal defects, foreign matter / voids, and film thickness unevenness, it is necessary to inspect each of them using a dedicated inspection device. Because of the cost of preparing multiple devices and the burden of setting up the bonded wafers that serve as samples, there is a demand for an inspection device and method that can simultaneously inspect for at least one of crystal defects, foreign matter / voids, and film thickness unevenness, and improve inspection throughput.

[0027] SUMMARY OF THE PRESENT EMBODIMENTS The present invention has been made in order to solve such problems, and an object of the present invention is to provide an inspection apparatus and an inspection method capable of improving the throughput of inspection. [Means for solving the problem]

[0028] An inspection apparatus according to one aspect of the present embodiment includes a polarization separation element that separates illumination light including a first linearly polarized light having a vibration direction in a first direction into a second linearly polarized light having a vibration direction perpendicular to each other, and a third linearly polarized light having a vibration direction perpendicular to each other, an objective lens that focuses the illumination light including the separated second linearly polarized light and the third linearly polarized light onto a sample and also focuses a first reflected light that is the illumination light reflected by the sample, and a polarization separation element that separates the first reflected light into a second reflected light including the second linearly polarized light and the third linearly polarized light, and a polarization separation element that separates the second linearly polarized light and the third linearly polarized light. The optical separation member separates the reflected light into a third reflected light including a third linearly polarized light, a first polarization separation member separates a fourth reflected light including each polarization component of the second linearly polarized light and the third linearly polarized light included in the second reflected light, the fourth reflected light including each polarization component of the second linearly polarized light and the third linearly polarized light included in the second reflected light, the vibration direction of which is perpendicular to the first direction, a second polarization separation member separates the third reflected light into a fifth reflected light including the second linearly polarized light and a sixth reflected light including the third linearly polarized light, a first light receiving element that receives the fourth reflected light, a second light receiving element that receives the fifth reflected light, and a third light receiving element that receives the sixth reflected light. With such a configuration, the throughput of the inspection can be improved.

[0029] In the above inspection device, the polarization separation element may include a Nomarski prism, and the polarization separation element may separate the first linearly polarized light into normal light in the second direction and abnormal light in the third direction, the vibration directions of which are perpendicular to each other; the optical separation member may include a half mirror, and the optical separation member may separate the first reflected light into the second reflected light including the normal light and the abnormal light and the third reflected light including the normal light and the abnormal light; the second polarization separation member may include a polarizing beam splitter, and the second polarization separation member may separate the third reflected light into the fifth reflected light including the abnormal light and the sixth reflected light including the normal light.

[0030] In the above-mentioned inspection device, the first polarization separation member may include a polarizing plate, and the first polarization separation member may separate the fourth reflected light, which includes each polarization component in the fourth direction in the normal light and the abnormal light contained in the second reflected light.

[0031] The above inspection device may further include a bandpass filter arranged between the second polarization separation member and the third light receiving element, and the third light receiving element may receive a seventh reflected light that is the sixth reflected light that passes through the bandpass filter.

[0032] The above inspection device may further include a bandpass filter arranged between the second polarization separation member and the second light receiving element, and the second light receiving element may receive an eighth reflected light that is the fifth reflected light that passes through the bandpass filter.

[0033] The above-mentioned inspection device may further include a bandpass filter disposed between the optical separation member and the second polarization separation member, and the second polarization separation member may separate an eighth reflected light, which is the third reflected light that passes through the bandpass filter, into the fifth reflected light and the sixth reflected light.

[0034] The above inspection device may further include a fourth light receiving element, wherein the first polarization separation member includes a polarizing beam splitter, and the first polarization separation member separates the normal light and the abnormal light contained in the second reflected light into the fourth reflected light including each polarization component in the fourth direction and a ninth reflected light including each polarization component in the first direction, and the fourth light receiving element may receive the ninth reflected light.

[0035] The above-mentioned inspection device may further include a bandpass filter arranged on an optical path until the illumination light is incident on the polarization separation element, and the polarization separation element may separate the illumination light that has passed through the bandpass filter.

[0036] In the above inspection apparatus, the illumination light may be white light including light of a continuous wavelength over a predetermined wavelength range.

[0037] In the above inspection apparatus, the illumination light may be monochromatic light having a peak at a predetermined central wavelength.

[0038] An inspection method according to one aspect of this embodiment includes the steps of: separating, by a polarization separation element, illumination light including a first linearly polarized light having a vibration direction in a first direction, the first linearly polarized light into a second linearly polarized light in a second direction and a third linearly polarized light in a third direction, the vibration directions of which are mutually perpendicular; focusing the illumination light including the separated second linearly polarized light and the third linearly polarized light on a sample by an objective lens, and focusing a first reflected light of the illumination light reflected by the sample by the objective lens; and separating the first reflected light into a second reflected light including the second linearly polarized light and the third linearly polarized light, and a third linearly polarized light including the second linearly polarized light and the third linearly polarized light. The method includes the steps of: separating the first reflected light including the second linearly polarized light and the third reflected light including the third linearly polarized light by an optical separation member; separating a fourth reflected light including each polarization component of a fourth direction whose vibration direction is perpendicular to the first direction in the second and third linearly polarized lights contained in the second reflected light by a first polarization separation member; separating the third reflected light into a fifth reflected light including the second linearly polarized light and a sixth reflected light including the third linearly polarized light by a second polarization separation member; and receiving the fourth reflected light by a first light receiving element, receiving the fifth reflected light by a second light receiving element, and receiving the sixth reflected light by a third light receiving element. With this configuration, the throughput of the inspection can be improved.

[0039] In the above inspection method, the polarization separation element may include a Nomarski prism, and the polarization separation element may separate the first linearly polarized light into ordinary light in a second direction and extraordinary light in a third direction, the vibration directions of which are perpendicular to each other; the optical separation member may include a half mirror, and the optical separation member may separate the first reflected light into a second reflected light including the ordinary light and the extraordinary light and a third reflected light including the ordinary light and the extraordinary light; the second polarization separation member may include a polarizing beam splitter, and the second polarization separation member may separate the third reflected light into a fifth reflected light including the extraordinary light and a sixth reflected light including the ordinary light.

[0040] In the above inspection method, the first polarization separation member may include a polarizing plate, and the first polarization separation member may separate the normal light and the abnormal light contained in the second reflected light into a fourth reflected light including each polarization component in the fourth direction.

[0041] In the above inspection method, in the receiving step, the third light receiving element may receive a seventh reflected light that has passed through a bandpass filter arranged between the second polarization separation member and the third light receiving element.

[0042] In the above inspection method, in the receiving step, the second light receiving element may receive an eighth reflected light that has passed through a bandpass filter arranged between the second polarization separation member and the second light receiving element.

[0043] In the above inspection method, in the step of separating using the second polarization separation member, the second polarization separation member may separate the eighth reflected light, which is the third reflected light that has passed through a bandpass filter arranged between the optical separation member and the second polarization separation member, into the fifth reflected light and the sixth reflected light.

[0044] In the above inspection method, the first polarization separation element may include a polarizing beam splitter, and the first polarization separation element may separate the normal light and the abnormal light contained in the second reflected light into a fourth reflected light including each polarization component in the fourth direction and a ninth reflected light including each polarization component in the first direction, and in the receiving step, the ninth reflected light may be received by a fourth light receiving element.

[0045] In the above inspection method, in the step of splitting using the polarization separation element, the illumination light may be split after passing through a bandpass filter arranged on the optical path before the illumination light is incident on the polarization separation element.

[0046] In the above inspection method, the illumination light may be white light including light of a continuous wavelength over a predetermined wavelength range.

[0047] In the above inspection method, the illumination light may be monochromatic light having a peak at a predetermined central wavelength. Effect of the Invention

[0048] According to the present invention, it is possible to provide an inspection apparatus and an inspection method capable of improving the throughput of inspection. [Brief description of the drawings]

[0049] [Figure 1] FIG. 1 is a diagram illustrating an example of a defect of interest in a bonded wafer. [Diagram 2] 1A and 1B are diagrams illustrating examples of inspection methods and conditions for a target defect in a bonded wafer. [Diagram 3] FIG. 1 is a diagram illustrating a defect of interest in a hetero epitaxial wafer. [Figure 4] 1A and 1B are diagrams illustrating an example of an inspection method and conditions for a target defect in a hetero epitaxial wafer. [Diagram 5] 1 is a configuration diagram illustrating an inspection device according to an embodiment; [Figure 6] 1A is a diagram illustrating an example of the vibration direction of polarized light when the optical axis of illumination light and reflected light is set in the Z-axis direction in the inspection device according to the embodiment. FIG. [Figure 7] FIG. 1 is a flow chart illustrating an inspection method according to an embodiment. [Figure 8] 1 is a configuration diagram illustrating an inspection device according to a first embodiment. [Figure 9] FIG. 11 is a configuration diagram illustrating an inspection device according to a second embodiment. [Figure 10] FIG. 11 is a configuration diagram illustrating an inspection device according to a third embodiment. [Figure 11] 13 is a diagram illustrating an example of the vibration direction of polarized light when the optical axes of illumination light and reflected light are set in the Z-axis direction in the inspection device according to the third embodiment. FIG. [Figure 12] FIG. 11 is a configuration diagram illustrating an inspection device according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0050] The specific configuration of this embodiment will be described below with reference to the drawings. The following description shows a preferred embodiment of the present invention, and the scope of the present invention is not limited to the following embodiment. In the following description, parts with the same reference numerals indicate substantially the same contents.

[0051] (Overview of the embodiment) First, an overview of the embodiment will be described. Fig. 5 is a configuration diagram illustrating an inspection device according to the embodiment. As shown in Fig. 5, the inspection device 100 includes a light source 10, lenses 11-14, an objective lens 15, a slit 16, polarization separation members 21-23, optical separation members HM1 and HM2, a mirror GM, a polarization separation element 25, and light receiving elements 31-33.

[0052] The light source 10 generates illumination light L1. The illumination light L1 includes, for example, broadband light with continuous wavelengths over a predetermined wavelength range. The illumination light L1 is, for example, white light. In this case, the light source 10 is a white light source. Note that, as described below, the light source 10 may include narrowband light having a peak at a predetermined central wavelength. The narrowband light is, for example, monochromatic light.

[0053] Illumination light L1 generated by light source 10 is incident on lens 11. Lens 11 collects illumination light L1 emitted from light source 10. Illumination light L1 collected by lens 11 passes through slit 16 formed in a slit plate. For example, illumination light L1 is focused at slit 16. Illumination light L1 that has passed through slit 16 is incident on polarization separation member 21. Polarization separation member 21 converts the incident illumination light L1 so that it contains linearly polarized light. Polarization separation member 21 is, for example, a polarizing plate. It should be noted that polarization separation member 21 may be a polarizing beam splitter.

[0054] 6 is a diagram illustrating the vibration direction of polarized light when the optical axis of illumination light and reflected light is set in the Z-axis direction in the inspection device 100 according to the embodiment. As shown in FIG. 6, when the optical axis of illumination light L1 is set in the Z-axis direction, the XY plane is perpendicular to the optical axis. That is, the X-axis direction and the Y-axis direction are perpendicular to the optical axis. Here, the vibration direction of the linearly polarized light transmitted through the polarization separation member 21 is set to the X-axis direction. Then, the polarization separation member 21 converts the illumination light L1 to include linearly polarized light whose vibration direction is in the X-axis direction.

[0055] Illumination light L1 including linearly polarized light whose vibration direction is in the X-axis direction is incident on the optical separation member HM1. The optical separation member HM1 does not have polarization characteristics, and separates the illumination light L1 by transmitting a part of the incident illumination light L1 and reflecting a part of it. The optical separation member HM1 is, for example, a half mirror. The illumination light L1 separated by the optical separation member HM1 is collected by the lens 12. For example, the illumination light L1 is converted into parallel light by the lens 12. The illumination light L1 collected by the lens 12 is reflected by the mirror GM. The mirror GM is, for example, a galvanic mirror. The illumination light L1 reflected by the mirror GM is incident on the polarization separation element 25 via the lens 13 and the lens 14. For example, the illumination light L1 is converted into parallel light by the lens 14 and incident on the polarization separation element 25.

[0056] The polarization separation element 25 includes, for example, a Nomarski prism. The polarization separation element 25 separates the linearly polarized light contained in the illumination light L1 into two linearly polarized lights whose vibration directions are perpendicular to each other. The two separated linearly polarized lights are called ordinary light and extraordinary light. Therefore, the illumination light L2 transmitted through the polarization separation element 25 includes ordinary light and extraordinary light. The polarization separation element 25 may include a prism other than a Nomarski prism.

[0057] As shown in FIG. 6, the ordinary light is linearly polarized light that oscillates in the direction of +45[deg] with respect to the X-axis in the XY plane. The extraordinary light is linearly polarized light that oscillates in the direction of -45[deg] with respect to the X-axis in the XY plane. The arrangement of the polarization separation element 25 is set so as to obtain such a polarization arrangement. Thus, the polarization separation element 25 separates the linearly polarized light in the X-axis direction in the illumination light L1, which includes linearly polarized light whose oscillation direction is in the X-axis direction, into linearly polarized light in the +45[deg] direction and linearly polarized light in the -45[deg] direction, whose oscillation directions are mutually orthogonal. The ordinary light and the extraordinary light are shifted perpendicularly to the optical axis by the shear amount S in the -45[deg] direction. The ordinary light and the extraordinary light have a relative phase difference due to the unevenness of the parts separated by the shear amount S. The offset phase difference can be set arbitrarily by adjusting the polarization separation element 25, such as a Nomarski prism. The illumination light L2 transmitted through the polarization separation element 25 is incident on the objective lens 15.

[0058] The objective lens 15 focuses the illumination light L2, which includes the separated linearly polarized light in the +45[deg] direction and the linearly polarized light in the -45[deg] direction, on the sample SMP. As a result, the illumination light L2 illuminates the sample SMP. The sample SMP is, for example, but not limited to, a bonded wafer, a hetero epitaxial wafer, etc. The illumination light L2 is focused on the sample SMP. The illumination light L2 that illuminates the sample SMP is reflected by the sample SMP. The objective lens 15 focuses the reflected light R1 that is the illumination light L2 reflected by the sample SMP. The reflected light R1 passes through the polarization separation element 25 via the objective lens 15. The reflected light R1 that passes through the polarization separation element 25 can be considered to include two linearly polarized lights whose vibration directions are perpendicular to each other and have a phase difference. The amplitudes of the ordinary light and the extraordinary light at this time are Eo and Ee, respectively. The phases are also δo and δe, respectively. A wave of wave number K traveling along the optical axis Z can be written as follows, where K=2π / λ, λ is the central wavelength, and the time term is omitted.

[0059]

number

number

[0060] The reflected light R1 transmitted through the polarization separation element 25 is reflected by the mirror GM via the lenses 14 and 13. The reflected light R1 then passes through the optical separation member HM1 via the lens 12 and enters the optical separation member HM2. The optical separation member HM2 includes, for example, a half mirror. Like the optical separation member HM1, the optical separation member HM2 does not have polarization properties and separates the reflected light R1 by transmitting part of the incident reflected light R1 and reflecting part of it. Therefore, the optical separation member HM2 separates the reflected light R1 into reflected light R2 including ordinary light and extraordinary light, and reflected light R3 including ordinary light and extraordinary light.

[0061] The reflected light R2 separated by the optical separation member HM2 is incident on the polarization separation member 22. The polarization separation member 22 includes, for example, a polarizing plate. The polarization separation member 22 may be a polarizing beam splitter. The polarization separation member 22 guides the Y-axis polarization components of the ordinary light and the extraordinary light contained in the reflected light R2 to the light receiving element 31. That is, the polarization separation member 22 separates the reflected light R4 containing the Y-axis polarization components of the ordinary light and the extraordinary light contained in the reflected light R2, the vibration direction of which is perpendicular to the X-axis direction. When the polarization separation member 22 is a polarizing plate, the polarization separation member 22 transmits the polarization components of the ordinary light and the extraordinary light whose vibration direction is the Y-axis direction. The reflected light R4 separated by the polarization separation member 22 is incident on the light receiving element 31. The light receiving element 31 receives the reflected light R4. When the optical separation member HM2 is a half mirror, the intensity of the reflected light R2 is half that of the reflected light R1. Furthermore, when the polarization separation member 22 is a polarizing plate that transmits a polarized component with an angle of 45 [deg], the amplitude of the reflected light R4 is cos45 [deg] = 1 / √2. Therefore, the light receiving element 31 detects the differential interference intensity Idic+ shown below.

[0062]

number

[0063] On the other hand, the reflected light R3 separated by the optical separating member HM2, which has no polarization characteristics, also contains the ordinary light and the extraordinary light of the expressions (1) and (2). The reflected light R3 separated by the optical separating member HM2 is incident on the polarization separating member 23. The polarization separating member 23 includes, for example, a polarizing beam splitter.

[0064] 6, the polarization separation member 23 is installed so that the vibration direction of transmission and the vibration direction of reflection match the vibration direction of ordinary light (+45 [deg] direction) and the vibration direction of extraordinary light (-45 [deg] direction). Therefore, the polarization separation member 23 separates the reflected light R3 into reflected light R6 containing ordinary light and reflected light R5 containing extraordinary light. This allows the polarization separation member 23 to separate the ordinary light and extraordinary light into p-polarized light and s-polarized light.

[0065] The reflected light R5 is incident on the light receiving element 32. The light receiving element 32 receives the reflected light R5. The reflected light R6 is incident on the light receiving element 33. The light receiving element 33 receives the reflected light R6. As a result, the light receiving elements 32 and 33 detect the reflected light containing s-polarized light and the reflected light containing p-polarized light, respectively. The detection intensities of the light receiving elements 32 and 33 are expressed by the following equations (4) and (5).

[0066]

number

number

[0067] In the inspection device 100 of this embodiment, the light receiving element 31 detects the inspection result by the differential interference method using white light. Therefore, the light receiving element 31 can detect, for example, crystal defects. For example, when the sample SMP is a bonded wafer, the light receiving element 31 can inspect crystal defects such as scratches, pits, bumps, and particles. Also, when the sample SMP is a hetero epitaxial wafer, it can inspect hexagonal bumps, cracks, and slips.

[0068] The light receiving element 32 detects the inspection result by the bright field observation method using white light. Therefore, the light receiving element 32 can detect defects different from those of the light receiving element 31. For example, the light receiving element 32 can detect voids when the sample SMP is a bonded wafer. Also, for example, the light receiving element 32 can detect particles and V-shaped V-pits when the sample SMP is a hetero epitaxial wafer.

[0069] Next, the inspection method according to the present embodiment will be described with reference to Fig. 7, which is a flow chart illustrating the inspection method according to the embodiment.

[0070] As shown in step S11 of Fig. 7, the linearly polarized light of the illumination light L1 is split into two linearly polarized light beams whose vibration directions are mutually orthogonal. Specifically, for example, in the illumination light L1 containing linearly polarized light beams whose vibration direction is in the X-axis direction, the linearly polarized light beams in the X-axis direction are split by the polarization splitter 25 into linearly polarized light beams in the +45[deg] direction and linearly polarized light beams in the -45[deg] direction whose vibration directions are mutually orthogonal. For example, the polarization splitter 25 may include a Nomarski prism, and the polarization splitter may split the linearly polarized light beams in the X-axis direction into ordinary light beams in the +45[deg] direction and extraordinary light beams in the -45[deg] direction.

[0071] Next, as shown in step S12, the illumination light L2 including the two separated linearly polarized lights is focused on the sample SMP, and the reflected light R1 reflected by the illumination light L2 from the sample SMP is focused. Specifically, the illumination light L2 including the separated linearly polarized lights in the +45[deg] and -45[deg] directions is focused on the sample SMP by the objective lens 15, and the reflected light R1 reflected by the illumination light L2 from the sample SMP is focused on the objective lens 15.

[0072] Next, as shown in step S13, the reflected light R1 is separated without polarization characteristics. Specifically, the reflected light R1 is separated by an optical separation member HM2 into a reflected light R2 containing ordinary light and extraordinary light, and a reflected light R3 containing ordinary light and extraordinary light. For example, the optical separation member may include a half mirror.

[0073] Next, as shown in step S14, the two linearly polarized light components in the Y-axis direction are separated. Specifically, the reflected light R4 containing the Y-axis polarization components in the ordinary light and extraordinary light contained in the reflected light R2 is separated by the polarization separation member 22. The polarization separation member 22 may include a polarizing plate.

[0074] Next, as shown in step S15, the reflected light R3 is separated into reflected light R6 containing ordinary light and reflected light R5 containing extraordinary light. Specifically, the polarization separation member 23 includes a polarizing beam splitter, and the reflected light R3 is separated by the polarization separation member 23 into reflected light R6 containing ordinary light and reflected light R5 containing extraordinary light.

[0075] Next, as shown in step S16, the reflected light R4 to R6 are received by the light receiving elements 31 to 33. Specifically, the reflected light R4 is received by the light receiving element 31, the reflected light R5 is received by the light receiving element 32, and the reflected light R6 is received by the light receiving element 33. In this manner, the inspection can be performed.

[0076] In this embodiment, while the differential interference method is available, it is possible to simultaneously perform differential interference observation and bright-field observation in one inspection without the need to attach and detach the polarization separation element 25 and the polarization separation members 22 and 23. Therefore, it is possible to significantly improve the throughput of inspecting the sample SMP.

[0077] (Embodiment 1) Next, an inspection device according to the first embodiment will be described. The inspection device according to the present embodiment simultaneously inspects for crystal defects such as pits and scratches, foreign bodies and voids, as well as unevenness in film thickness, by using a confocal optical system using, for example, a white light source. FIG. 8 is a configuration diagram illustrating an inspection device according to the first embodiment. As shown in FIG. 8, the inspection device 1 includes a light source 10, lenses 11-14, an objective lens 15, a slit 16, polarization separation members 21-23, optical separation members HM1 and HM2, a mirror GM, a polarization separation element 25, and light receiving elements 31-33, similar to the inspection device 100.

[0078] In this embodiment, for example, the polarization separation element 25 includes a Nomarski prism. The Nomarski prism separates linearly polarized light in the X-axis direction into ordinary light in the +45[deg] direction and extraordinary light in the -45[deg] direction, whose vibration directions are mutually orthogonal. The optical separation member HM2 includes a half mirror. The half mirror separates the reflected light R1 into reflected light R2 including ordinary light and extraordinary light, and reflected light R3 including ordinary light and extraordinary light.

[0079] The polarization separation member 22 includes a polarizing plate. The polarizing plate separates the ordinary light and the extraordinary light contained in the reflected light R2 into a reflected light R4 including each polarization component in the Y-axis direction. The light receiving element 31 detects a differential interference intensity Idic+ of the reflected light R4.

[0080] The polarization separation member 23 includes a polarization beam splitter. The polarization beam splitter separates the reflected light R3 into reflected light R6 containing ordinary light and reflected light R5 containing extraordinary light. The light receiving element 32 receives the reflected light R5 containing extraordinary light as s-polarized light.

[0081] The inspection device 1 further includes a bandpass filter BPF. The bandpass filter BPF is disposed between the polarization separation member 23 and the light receiving element 33. The reflected light R6, which includes normal light as p-polarized light separated by the polarization separation member 23, is incident on the bandpass filter BPF. The reflected light R6 incident on the bandpass filter BPF transmits monochromatic light having a narrow band wavelength limited to a predetermined wavelength range. The reflected light R7 transmitted through the bandpass filter BPF is, for example, monochromatic light having a peak at a predetermined central wavelength. The reflected light R7 includes, for example, monochromatic light of 546 [nm]. The light receiving element 33 receives the reflected light R7 that is the reflected light R6 transmitted through the bandpass filter BPF. Thus, the light receiving element 33 can detect the film thickness unevenness by detecting the reflected light R7 including the monochromatic light. As a result, the inspection device 1 of this embodiment can simultaneously inspect the film thickness unevenness in addition to crystal defects such as pits and scratches, foreign matter and voids, by one imaging.

[0082] 7, the inspection method of this embodiment receives reflected light R7 that has passed through a bandpass filter BPF arranged between the polarization separation member 23 and the light receiving element 33. Other configurations and operations are included in the description of the outline of the embodiment.

[0083] In this manner, in this embodiment, in the setting of the differential interference optical system, bright field observation and white or monochrome observation can be performed simultaneously without switching the optical system. In other words, it is possible to obtain multiple pieces of information with one image capture. Therefore, the inspection time can be significantly reduced, and the throughput of the inspection can be significantly improved.

[0084] (Embodiment 2) Next, an inspection device according to a second embodiment will be described. The inspection device according to this embodiment simultaneously inspects crystal defects such as pits and scratches, unevenness in film thickness, and the degree of polarization by a confocal optical system using a white light source. FIG. 9 is a configuration diagram illustrating an inspection device according to a second embodiment. As shown in FIG. 9, the inspection device 2 includes a light source 10, lenses 11-14, an objective lens 15, a slit 16, polarization separation members 21-23, optical separation members HM1 and HM2, a mirror GM, a polarization separation element 25, light receiving elements 31-33, and a bandpass filter BPF, similar to the inspection device 1.

[0085] In the inspection device 1 described above, the bandpass filter BPF is disposed between the polarization separation member 23 and the light receiving element 33, but in the inspection device 2 of this embodiment, the bandpass filter BPF is disposed between the optical separation member HM2 and the polarization separation member 23. Thus, the reflected light R3 split by the optical separation member HM2 is converted by the bandpass filter BPF into reflected light R8 containing monochromatic light. The polarization separation member 23 splits the reflected light R8, which is the reflected light R3 transmitted through the bandpass filter BPF, into reflected light R5 and reflected light R6. That is, the reflected light R8 converted into monochromatic light is split by the polarization separation member 23 into reflected light R6 containing ordinary light as p-polarized light and reflected light R5 containing extraordinary light as s-polarized light.

[0086] Instead of being disposed between the optical separation member HM2 and the polarization separation member 23, the bandpass filter BPF may be disposed between the polarization separation member 23 and the light receiving element 32, and between the polarization separation member 23 and the light receiving element 33. Thus, the light receiving element 32 may receive reflected light obtained by transmitting the reflected light R5 through the bandpass filter BPF, and the light receiving element 33 may receive reflected light R7 obtained by transmitting the reflected light R6 through the bandpass filter BPF. In this case, bandpass filters BPFs that transmit different wavelengths may be used. This makes it possible to apply the present invention to two-wavelength film thickness unevenness.

[0087] In this embodiment, it is difficult to suppress the intra-film interference occurring around the voids because it is difficult to observe in the bright field with broadband light. (However, if the inspection of the film thickness unevenness is not required, it is possible to select the void inspection without using the bandpass filter BPF.) In this embodiment, instead of inspecting the voids, information about the polarization characteristics of the film can be obtained. For example, here, the information about the polarization characteristics of the film is defined as the degree of polarization (α), which can be calculated as shown in equation (6) and can be visualized. In this embodiment, Is in the above-mentioned equation (4) and Ip in equation (5) are the intensities of the same wavelength.

[0088]

number

[0089] The inspection device 2 of this embodiment can simultaneously inspect crystal defects such as pits and scratches, unevenness in film thickness, and the degree of polarization (or, by removing the bandpass filter BPF, crystal defects such as pits and scratches, foreign matter / voids, and the degree of polarization) in one image capture. Deviations in the shear amounts of the detection intensity Is of the light receiving element 32 and the detection intensity Ip of the light receiving element 33 can be avoided by correcting them on the image.

[0090] The degree of polarization can be displayed as a grayscale image, for example, from 0 to 255, by appropriate scale conversion. Therefore, it can be used to separate the polarization information of the differential interference contrast due to the difference in domain direction of the optically anisotropic crystal and the unevenness.

[0091] 7, the inspection method of this embodiment separates reflected light R8, which is reflected light R3 transmitted through a bandpass filter BPF arranged between the optical separation member HM2 and the polarization separation member 23, into reflected light R5 and reflected light R6 by the polarization separation member 23. Other configurations and operations are included in the description of the outline of the embodiment and embodiment 1.

[0092] (Embodiment 3) Next, an inspection device according to a third embodiment will be described. The inspection device of this embodiment simultaneously inspects the film thickness unevenness, the degree of polarization, and the phase difference by a confocal optical system using a white light source. FIG. 10 is a configuration diagram illustrating an inspection device according to a third embodiment. As shown in FIG. 10, the inspection device 3 includes a light source 10, lenses 11 to 14, an objective lens 15, a slit 16, polarization separation members 21, 23, and 24, optical separation members HM1 and HM2, a mirror GM, a polarization separation element 25, light receiving elements 31 to 34, and a bandpass filter BPF. Thus, the inspection device 3 of this embodiment further includes a light receiving element 34. Also, a polarization separation member 24 is arranged instead of the polarization separation member 22.

[0093] In the inspection device 3 of this embodiment, the bandpass filter BPF is disposed on the optical path before the illumination light L1 enters the polarization separation element 25. For example, the bandpass filter BPF is disposed between the light source 10 and the optical separation member HM1, specifically, between the lens 11 and the slit 16. This converts the illumination light L1 into monochromatic light. Therefore, the illumination light L1 is monochromatic light having a peak at a predetermined central wavelength. Thus, the polarization separation element 25 separates the illumination light that has passed through the bandpass filter BPF. Note that instead of disposing the bandpass filter BPF, the light source 10 may be a monochromatic light source. If the phase difference can be substituted by the central wavelength of the broadband light, white light may be used without using the bandpass filter BPF of the illumination light L1, but in that case, it is difficult to inspect the film unevenness.

[0094] In the inspection device 3, a polarizing beam splitter is arranged as the polarization separation member 24. Fig. 11 is a diagram illustrating the vibration direction of polarized light when the optical axes of the illumination light and the reflected light are set in the Z-axis direction in the inspection device 3 according to the third embodiment.

[0095] As shown in FIG. 11, in the inspection device 3, the polarization beam splitter in the polarization separation member 24 is arranged so that the polarization direction of the polarization beam splitter faces the Y-axis direction and the X-axis direction. In this way, the polarization separation member 24 includes a polarization beam splitter, and the polarization beam splitter splits the ordinary light and the extraordinary light contained in the reflected light R2 into a reflected light R4 including each polarization component in the Y-axis direction and a reflected light R9 including each polarization component in the X-axis direction. The light receiving element 31 receives the reflected light R4 including linearly polarized light in the Y-axis direction. The light receiving element 34 receives the reflected light R9 including linearly polarized light in the X-axis direction. The light receiving element 31 detects the differential interference intensity Idic+. ​​The light receiving element 34 detects the differential interference intensity Idic-. The differential interference intensity Idic+ is expressed by equation (7) similar to equation (3). The differential interference intensity Idic- is expressed by equation (8) because it is interference with a phase shift of 180 degrees.

[0096]

number

number

[0097] By taking the difference between equations (7) and (8), the phase difference can be calculated as in equation (9). If we assume that the phase difference is a pseudo surface unevenness, the differential coefficient in the shear direction can be written as in equation (10). Therefore, by performing an integral calculation of this, it is possible to restore the pseudo unevenness of the defect. In the case of white light, the central wavelength is used for λ.

[0098]

number

number

[0099] The inspection device 3 of this embodiment uses light receiving elements 31 to 34. By using monochromatic illumination light transmitted through a band pass filter BPF or a light source that generates monochromatic illumination light, it is possible to simultaneously inspect the phase difference, film thickness unevenness, and degree of polarization.

[0100] In the inspection method of this embodiment, when the linearly polarized light of the illumination light is split into two linearly polarized lights whose vibration directions are orthogonal to each other in step S11 of FIG. 7, the monochromatic illumination light transmitted through the bandpass filter BPF is split. Also, when the polarization components in the Y-axis direction of the two linearly polarized lights are split in step S14 of FIG. 7, the polarization splitting member 24 splits the ordinary light and the extraordinary light contained in the reflected light R2 into reflected light R4 containing the polarization components in the Y-axis direction and reflected light R9 containing the polarization components in the X-axis direction. Then, the light receiving element 34 receives the reflected light R9. Other configurations and operations are included in the description of the outline of the embodiment and the first and second embodiments.

[0101] (Embodiment 4) Next, a description will be given of an inspection device according to embodiment 4. The inspection device of this embodiment simultaneously inspects crystal defects such as pits and scratches, phase difference, foreign matter and voids, and the degree of polarization by a confocal optical system using a white light source.

[0102] Fig. 12 is a configuration diagram illustrating an inspection device according to the fourth embodiment. As shown in Fig. 12, the inspection device 4 has a configuration in which the bandpass filter BPF is omitted from the inspection device 3 of the above-mentioned third embodiment. The other configurations and operations are the same as those of the third embodiment. The inspection device 4 of this embodiment uses the light receiving elements 31 to 34 and uses the illumination light L1 of white light, thereby being able to simultaneously inspect the film thickness unevenness, the degree of polarization, and the phase difference.

[0103] In the outline of the embodiment and in the first to fourth embodiments, the optical system for simultaneously inspecting multiple types of objects can be changed according to the desired information. For example, white light is used to suppress the interference contrast within the film. This allows "normal light" and "abnormal light" to be separated and received independently to avoid double images in bright-field observation by differential interference contrast. By setting these two bright-field images in advance as monochromatic light and white light, monochromatic light and white light, or white light and white light, they can be used for analysis of film unevenness, foreign body / void inspection, degree of polarization, and differential interference phase difference.

[0104] In the outline of the embodiment and the first to fourth embodiments, the following points are utilized for the purpose of simultaneously measuring unevenness in film thickness, foreign matter / voids, and crystal defects, and inspecting and evaluating with high throughput.

[0105] (1) When using a transparent substrate (sapphire, spinel, synthetic quartz, etc.), the back surface reflected light can be eliminated by using a confocal optical system. Therefore, the net surface reflected light can be accurately measured. Confocal optics and differential interference optics can coexist. If the influence of the substrate can be sufficiently ignored, a non-confocal optical system can also be used. Note that the confocal optical system can be a method other than the slit 16 method as long as it uses white light.

[0106] (2) Instead of splitting the reflected light as in conventional spectroscopic film thickness meters, the illumination light is monochromatic (narrowband light) and the reflection intensity of the sample SMP is measured. The measurement wavelength may be selectable so that it can be optimized depending on the sample SMP. This inspection is performed in a bright field (either Ip or Is). Ip and Is can be considered as linearly polarized light split into two by a polarization splitter element 25 such as a Nomarski prism, with the vibration directions perpendicular to each other. Therefore, they can be separated by a polarizing beam splitter PBS and detected by separate light receiving elements without including the phase difference generated by differential interference. The contrast of this bright field image is correlated with the film thickness (the wavelength and the optical constants of the sample SMP are fixed), making it possible to inspect for film unevenness. By measuring a sample with a known reflection spectrum, such as silicon or quartz glass, as a reference sample for absolute reflectance, the wavelength dependency of the optical system itself can be corrected by calculation.

[0107] (3) In order to inspect defects such as foreign bodies and voids, the above (2) would cause interference fringes around voids and transparent foreign bodies, hindering the inspection. Therefore, the bright field Is is changed to white light (broadband light). By adding up the interference fringes of various wavelengths generated by white light, the interference fringe contrast can be suppressed. In addition, the use of broadband light can also reduce coherence. At the same time, the interference contrast inside the film is also suppressed, making it easier to detect and distinguish foreign bodies and voids.

[0108] (4) Crystal defects are nano-order irregularities such as pits and scratches, and a differential interference optical system is required to inspect them. However, in bonded wafers with films, the interference contrast within the film is prominent, and the weakness of the crystal defects makes it difficult to detect the contrast. Therefore, by using white light (broadband light) as in (3), the interference contrast within the film can be suppressed, making it possible to stably inspect crystal defects.

[0109] (1) to (4) are examples of optical systems for simultaneously measuring film unevenness, foreign bodies / voids, and pits / scratches. (2) The inspection items can be changed between the case where bright field observation (Is and Ip) is performed at the same wavelength (2a) and the case where different single wavelengths are used (2b). Furthermore, when a polarizing beam splitter PBS is used as the analyzer of the differential interference optical system, the differential interference contrast (DIC+) and the differential interference contrast (DIC-) with a phase inversion of 180[deg] can be measured by the respective light receiving elements 31 and 34. Since the difference between these two differential interference contrasts includes a phase change, it is possible to quantify only the phase difference component by calculating it together with the result of (2a) when measured at the same wavelength.

[0110] (5) When Ip and Is are inspected at the same wavelength, the polarization directions are perpendicular to each other, so the ratio of these (Ip-Is) / (Ip+Is) can be used to easily inspect the relative orientation of crystal domains. Film unevenness and the film's polarization characteristics (distortion) can also be inspected simultaneously. Since differential interference contrast in principle includes the effect of polarization, the extent of this effect can be confirmed.

[0111] (6) When Ip and Is are inspected at two different wavelengths, the dynamic range of the film thickness for film unevenness inspection can be expanded, or a non-transparent metal electrode on the wafer can be identified.

[0112] (7) By measuring DIC+, DIC-, Ip, and Is at the same wavelength, the differential interference phase difference δ can be quantified. If the offset of the phase difference caused by the Nomarski prism is set in advance, it can be calculated as an absolute value. cosδ=((DIC+)-(DIC-)) / 2√(Ip·Is)

[0113] If the film thickness is sufficiently uniform, the phase difference δ corresponds to the gradient, and therefore it is possible to restore the uneven shape of the defect by integration.

[0114] Although the embodiments of the present invention have been described above, the present invention includes appropriate modifications that do not impair the objects and advantages thereof, and is not limited to the above-mentioned embodiments. For example, depending on the position in the optical path where the bandpass filter BPF is installed, the items that can be simultaneously inspected may be combinations other than those of the embodiments 1 to 4. Also, combinations of the configurations of the embodiments 1 to 4 are included in the scope of the technical ideas of the embodiments. [Explanation of symbols]

[0115] 1, 2, 3, 4, 100 Inspection equipment 10 light source 11, 12, 13, 14 Lenses 15 Objective Lens 16 Slit 21, 22, 23, 24 Polarization separation member 25 Polarization separation element 31, 32, 33, 34 Photodetector BPF Bandpass Filter GM Mirror HM1, HM2 Optical isolation members L1, L2 illumination light R1, R2, R3, R4, R5, R6, R7, R8, R9 Reflected light SMP sample

Claims

1. a polarization splitter that splits, in illumination light including a first linearly polarized light having a vibration direction in a first direction, the first linearly polarized light into a second linearly polarized light having a vibration direction in a second direction and a third linearly polarized light having a vibration direction in a third direction, the vibration directions of the second linearly polarized light being mutually orthogonal; an objective lens that focuses the illumination light including the separated second linearly polarized light and the third linearly polarized light on a sample and also focuses a first reflected light of the illumination light reflected by the sample; an optical separation member that separates the first reflected light into a second reflected light including the second linearly polarized light and the third linearly polarized light and a third reflected light including the second linearly polarized light and the third linearly polarized light; a first polarization separation member that separates a fourth reflected light including polarization components of the second linearly polarized light and the third linearly polarized light included in the second reflected light, the polarization components having a fourth direction in which the vibration direction is perpendicular to the first direction; a second polarization separation member that separates the third reflected light into a fifth reflected light including the second linearly polarized light and a sixth reflected light including the third linearly polarized light; a first light receiving element that receives the fourth reflected light; a second light receiving element that receives the fifth reflected light; a third light receiving element that receives the sixth reflected light; a bandpass filter disposed between the second polarization separation member and the third light receiving element; Equipped with the third light receiving element receives a seventh reflected light obtained by transmitting the sixth reflected light through the band pass filter; Inspection equipment.

2. Further comprising a bandpass filter disposed between the second polarization separation member and the second light receiving element, the second light receiving element receives an eighth reflected light obtained by transmitting the fifth reflected light through the band pass filter; 2. The inspection device according to claim 1.

3. a polarization splitter that splits, in illumination light including a first linearly polarized light having a vibration direction in a first direction, the first linearly polarized light into a second linearly polarized light having a vibration direction in a second direction and a third linearly polarized light having a vibration direction in a third direction, the vibration directions of the second linearly polarized light being mutually orthogonal; an objective lens that focuses the illumination light including the separated second linearly polarized light and the third linearly polarized light on a sample and also focuses a first reflected light of the illumination light reflected by the sample; an optical separation member that separates the first reflected light into a second reflected light including the second linearly polarized light and the third linearly polarized light and a third reflected light including the second linearly polarized light and the third linearly polarized light; a first polarization separation member that separates a fourth reflected light including polarization components of the second linearly polarized light and the third linearly polarized light included in the second reflected light, the polarization components having a fourth direction in which the vibration direction is perpendicular to the first direction; a second polarization separation member that separates the third reflected light into a fifth reflected light including the second linearly polarized light and a sixth reflected light including the third linearly polarized light; a first light receiving element that receives the fourth reflected light; a second light receiving element that receives the fifth reflected light; a third light receiving element that receives the sixth reflected light; a bandpass filter disposed between the optical separation member and the second polarization separation member; Equipped with the second polarization separation member separates an eighth reflected light, which is the third reflected light transmitted through the band pass filter, into the fifth reflected light and the sixth reflected light; Inspection equipment.

4. the polarization separation element includes a Nomarski prism; the polarization separation element separates the first linearly polarized light into ordinary light in the second direction and extraordinary light in the third direction, the vibration directions of which are orthogonal to each other; the optical separation member includes a half mirror, the optical separation member separates the first reflected light into the second reflected light including the ordinary light and the extraordinary light, and the third reflected light including the ordinary light and the extraordinary light, the second polarization separation member includes a polarization beam splitter; the second polarization separation member separates the third reflected light into the fifth reflected light including the extraordinary light and the sixth reflected light including the ordinary light; The inspection device according to any one of claims 1 to 3.

5. the first polarization separation member includes a polarizing plate, the first polarization separation member separates the fourth reflected light including each polarization component in the fourth direction from the ordinary light and the extraordinary light included in the second reflected light, 5. The inspection apparatus according to claim 4.

6. The illumination light is white light including light of a continuous wavelength over a predetermined wavelength range. The inspection device according to any one of claims 1 to 5.

7. a polarization splitter that splits, in illumination light including a first linearly polarized light having a vibration direction in a first direction, the first linearly polarized light into a second linearly polarized light having a vibration direction in a second direction and a third linearly polarized light having a vibration direction in a third direction, the vibration directions of the second linearly polarized light being mutually orthogonal; an objective lens that focuses the illumination light including the separated second linearly polarized light and the third linearly polarized light on a sample and also focuses a first reflected light of the illumination light reflected by the sample; an optical separation member that separates the first reflected light into a second reflected light including the second linearly polarized light and the third linearly polarized light, and a third reflected light including the second linearly polarized light and the third linearly polarized light; a first polarization separation member that separates a fourth reflected light including polarization components of the second linearly polarized light and the third linearly polarized light included in the second reflected light, the polarization components having a fourth direction in which the vibration direction is perpendicular to the first direction; a second polarization separation member that separates the third reflected light into a fifth reflected light including the second linearly polarized light and a sixth reflected light including the third linearly polarized light; a first light receiving element that receives the fourth reflected light; a second light receiving element that receives the fifth reflected light; a third light receiving element that receives the sixth reflected light; Equipped with The illumination light is white light including light of a continuous wavelength over a predetermined wavelength range. Inspection equipment.

8. the polarization separation element includes a Nomarski prism; the polarization separation element separates the first linearly polarized light into ordinary light in the second direction and extraordinary light in the third direction, the vibration directions of which are orthogonal to each other; the optical separation member includes a half mirror, the optical separation member separates the first reflected light into the second reflected light including the ordinary light and the extraordinary light, and the third reflected light including the ordinary light and the extraordinary light, the second polarization separation member includes a polarization beam splitter; the second polarization separation member separates the third reflected light into the fifth reflected light including the extraordinary light and the sixth reflected light including the ordinary light; 8. The inspection apparatus according to claim 7.

9. the first polarization separation member includes a polarizing plate, The first polarization separation member separates the fourth reflected light including each polarization component in the fourth direction from the ordinary light and the extraordinary light included in the second reflected light.

9. The inspection apparatus according to claim 8.

10. Further comprising a fourth light receiving element, the first polarization separation member includes a polarization beam splitter; the first polarization separation member separates the ordinary light and the extraordinary light included in the second reflected light into the fourth reflected light including the polarization components in the fourth direction and a ninth reflected light including the polarization components in the first direction, The fourth light receiving element receives the ninth reflected light.

9. The inspection apparatus according to claim 8.

11. A step of separating, in illumination light including a first linearly polarized light having a vibration direction in a first direction, the first linearly polarized light into a second linearly polarized light having a vibration direction in a second direction and a third linearly polarized light having a vibration direction in a third direction, the vibration directions of the second linearly polarized light being mutually orthogonal to each other, by a polarization separation element; a step of collecting the illumination light including the separated second linearly polarized light and the third linearly polarized light on a sample by an objective lens, and collecting a first reflected light of the illumination light reflected by the sample by the objective lens; Separating the first reflected light into a second reflected light including the second linearly polarized light and the third linearly polarized light and a third reflected light including the second linearly polarized light and the third linearly polarized light by an optical separation member; A step of separating, by a first polarization separation member, a fourth reflected light including polarization components of the second linearly polarized light and the third linearly polarized light included in the second reflected light, the polarization components having a fourth direction whose vibration direction is perpendicular to the first direction; splitting the third reflected light by a second polarization splitting member into a fifth reflected light including the second linearly polarized light and a sixth reflected light including the third linearly polarized light; receiving the fourth reflected light by a first light receiving element, receiving the fifth reflected light by a second light receiving element, and receiving the sixth reflected light by a third light receiving element; Equipped with In the step of receiving light, causing the third light receiving element to receive seventh reflected light transmitted through a band pass filter disposed between the second polarization separating member and the third light receiving element; Testing method.

12. In the step of receiving light, causing the second light receiving element to receive the eighth reflected light transmitted through a band pass filter disposed between the second polarization separating member and the second light receiving element; The inspection method according to claim 11.

13. A step of separating, in illumination light including a first linearly polarized light having a vibration direction in a first direction, the first linearly polarized light into a second linearly polarized light having a vibration direction in a second direction and a third linearly polarized light having a vibration direction in a third direction, the vibration directions of the second linearly polarized light being mutually orthogonal to each other, by a polarization separation element; a step of collecting the illumination light including the separated second linearly polarized light and the third linearly polarized light on a sample by an objective lens, and collecting a first reflected light of the illumination light reflected by the sample by the objective lens; Separating the first reflected light into a second reflected light including the second linearly polarized light and the third linearly polarized light and a third reflected light including the second linearly polarized light and the third linearly polarized light by an optical separation member; A step of separating, by a first polarization separation member, a fourth reflected light including polarization components of the second linearly polarized light and the third linearly polarized light included in the second reflected light, the polarization components having a fourth direction whose vibration direction is perpendicular to the first direction; splitting the third reflected light by a second polarization splitting member into a fifth reflected light including the second linearly polarized light and a sixth reflected light including the third linearly polarized light; receiving the fourth reflected light by a first light receiving element, receiving the fifth reflected light by a second light receiving element, and receiving the sixth reflected light by a third light receiving element; Equipped with In the step of separating the light beams by the second polarization separating member, The second polarization separation member separates an eighth reflected light, which is the third reflected light transmitted through a bandpass filter disposed between the optical separation member and the second polarization separation member, into the fifth reflected light and the sixth reflected light. Testing method.

14. The polarization separation element includes a Nomarski prism, The first linearly polarized light is separated by the polarization separation element into ordinary light in a second direction and extraordinary light in a third direction, the vibration directions of which are orthogonal to each other; The optical separation member includes a half mirror, The first reflected light is separated by the optical separation member into a second reflected light including the ordinary light and the extraordinary light, and a third reflected light including the ordinary light and the extraordinary light; The second polarization separation member includes a polarization beam splitter; The third reflected light is separated by the second polarization separation member into a fifth reflected light including the extraordinary light and a sixth reflected light including the ordinary light. The inspection method according to any one of claims 11 to 13.

15. The first polarization separation member includes a polarizing plate, a fourth reflected light including each polarization component in the fourth direction is separated from the ordinary light and the extraordinary light included in the second reflected light by the first polarization separation member; The inspection method according to claim 14.

16. The illumination light is white light including light of a continuous wavelength over a predetermined wavelength range. The inspection method according to any one of claims 11 to 15.

17. A step of separating, in illumination light including a first linearly polarized light having a vibration direction in a first direction, the first linearly polarized light into a second linearly polarized light having a vibration direction in a second direction and a third linearly polarized light having a vibration direction in a third direction, the vibration directions of the second linearly polarized light being mutually orthogonal to each other, by a polarization separation element; a step of collecting the illumination light including the separated second linearly polarized light and the third linearly polarized light on a sample by an objective lens, and collecting a first reflected light of the illumination light reflected by the sample by the objective lens; Separating the first reflected light into a second reflected light including the second linearly polarized light and the third linearly polarized light and a third reflected light including the second linearly polarized light and the third linearly polarized light by an optical separation member; A step of separating, by a first polarization separation member, a fourth reflected light including polarization components of the second linearly polarized light and the third linearly polarized light included in the second reflected light, the polarization components having a fourth direction whose vibration direction is perpendicular to the first direction; splitting the third reflected light by a second polarization splitting member into a fifth reflected light including the second linearly polarized light and a sixth reflected light including the third linearly polarized light; receiving the fourth reflected light by a first light receiving element, receiving the fifth reflected light by a second light receiving element, and receiving the sixth reflected light by a third light receiving element; Equipped with The illumination light is white light including light of a continuous wavelength over a predetermined wavelength range. Testing method.

18. The polarization separation element includes a Nomarski prism, The first linearly polarized light is separated by the polarization separation element into ordinary light in a second direction and extraordinary light in a third direction, the vibration directions of which are orthogonal to each other; The optical separation member includes a half mirror, The first reflected light is separated by the optical separation member into a second reflected light including the ordinary light and the extraordinary light, and a third reflected light including the ordinary light and the extraordinary light; The second polarization separation member includes a polarization beam splitter; The third reflected light is separated by the second polarization separation member into a fifth reflected light including the extraordinary light and a sixth reflected light including the ordinary light. The inspection method according to claim 17.

19. The first polarization separation member includes a polarizing plate, a fourth reflected light including each polarization component in the fourth direction is separated from the ordinary light and the extraordinary light included in the second reflected light by the first polarization separation member; The inspection method according to claim 18.

20. The first polarization separation member includes a polarization beam splitter; the first polarization separation member separates the ordinary light and the extraordinary light contained in the second reflected light into a fourth reflected light including the polarization components in the fourth direction and a ninth reflected light including the polarization components in the first direction; In the step of receiving light, causing a fourth light receiving element to receive the ninth reflected light; The inspection method according to claim 18.

Images