Inspection device and inspection method

Abstract

To provide an inspection device and an inspection method capable of observing both of photoluminescence light and Raman scattering light by a simple configuration and advancing crystal evaluation.SOLUTION: An inspection device 1 includes: pulse light generation means 10 for generating pulse light 11 that has a longer wavelength than a wavelength of light corresponding to a bandgap of a sample 40 and performs multiphoton excitation of the sample 40; condensing means 20 including an objective lens 21, condenses the pulse light 11 by the objective lens 21 for the sample 40, and transmitting light 41 including photoluminescence light PL and Raman scattering light RS generated from the sample 40 by application of the pulse light 11 through the objective lens 21; first detection means 31 for detecting the photoluminescence light PL through the objective lens 21; and second detection means 32 for detecting the Raman scattering light RS through the objective lens 21.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an inspection apparatus and an inspection method. [Background technology]

[0002] A general photoluminescence measurement using photoluminescence light makes it possible to observe the polytype of a semiconductor wafer or internal defects caused by alteration of the crystal. However, with general photoluminescence measurement, it is difficult to observe stress distribution that does not involve alteration of the crystal, such as processing stress residue. Such stress residue may become the starting point for alteration or destruction of defects in subsequent epitaxial processes or thermal processes. For this reason, it is preferable to be able to evaluate the internal stress of the crystal.

[0003] For such evaluation, Raman spectroscopy using Raman scattered light is effective. Therefore, an inspection device that combines photoluminescence measurement with Raman spectroscopy is desired. However, when a general photoluminescence measurement is used as a base, band edge emission occurs at a wavelength very close to the excitation light. For this reason, when Raman spectroscopy is performed using the excitation light for photoluminescence measurement, there is a problem that the band edge emission covers up the Raman scattered light, which is a weak signal. Therefore, in order to combine Raman spectroscopy, it is necessary to take measures such as using a light source with a different wavelength from the light source for photoluminescence measurement. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2003-194718 A Summary of the Invention [Problem to be solved by the invention]

[0005] For example, Patent Document 1 discloses a method for detecting internal defects in a sample including a wide band gap semiconductor such as gallium nitride (GaN), in which a laser beam having a wavelength longer than the wavelength of light corresponding to the band gap is focused on the sample and photoluminescence light due to multiphoton excitation is detected. Patent Document 1 also discloses that the multiphoton excitation photoluminescence measurement is further combined with Raman spectrum measurement to detect internal lattice vibration. However, Patent Document 1 does not disclose that the excitation light used in the multiphoton excitation photoluminescence measurement and the excitation light used in the Raman spectrum measurement are the same wavelength, and does not disclose a specific configuration.

[0006] There is a demand for an inspection device and an inspection method that can detect both photoluminescence light and Raman scattered light with a simple configuration that uses a light source used in multiphoton excitation photoluminescence measurement, and that can enhance crystal evaluation.

[0007] The present disclosure has been made in consideration of such problems, and provides an inspection device and inspection method that have a simple configuration and are capable of observing both photoluminescence light and Raman scattered light, thereby enabling advanced crystal evaluation. [Means for solving the problem]

[0008] An inspection apparatus according to one aspect of this embodiment includes a pulsed light generating means for generating pulsed light having a wavelength longer than the wavelength of light corresponding to the band gap of a sample, the pulsed light causing multiphoton excitation of the sample, a focusing means including an objective lens for focusing the pulsed light onto the sample with the objective lens and transmitting light including photoluminescence light and Raman scattered light generated from the sample by irradiation with the pulsed light through the objective lens, a first detection means for detecting the photoluminescence light that has transmitted through the objective lens, and a second detection means for detecting the Raman scattered light that has transmitted through the objective lens.

[0009] In the above inspection apparatus, the sample may include a semiconductor wafer.

[0010] In the above inspection device, the focusing means may further include a half mirror arranged between the objective lens and the second detection means on the optical path of the pulsed light, the half mirror transmitting either the pulsed light or the Raman scattered light and reflecting the other, a first pinhole arranged between the half mirror and the pulsed light generation means, and a second pinhole arranged between the second detection means and the half mirror, and at least the second detection means may detect the Raman scattered light generated from a portion of the sample where the pulsed light is focused.

[0011] In the above inspection device, the half mirror may reflect the pulsed light and transmit the Raman scattered light and the photoluminescent light, or transmit the pulsed light and reflect the Raman scattered light and the photoluminescent light.

[0012] In the above-mentioned inspection apparatus, the focusing means may further include a dichroic mirror arranged between the half mirror and the first detection means and the second detection means, and the dichroic mirror may transmit either the photoluminescence light or the Raman scattered light and reflect the other.

[0013] In the above inspection device, the dichroic mirror may reflect or transmit light having a central wavelength of the pulsed light and a wavelength range of at most ±100 nm therearound, and guide the wavelength range to the second detection means.

[0014] In the above inspection device, the focusing means may further include a first filter arranged between the dichroic mirror and the first detection means, and the first filter may include at least one of a short-pass filter that transmits light with a short wavelength of 400 nm or less, a long-pass filter that transmits light with a wavelength longer than 700 nm, and a band-pass filter that transmits light with a wavelength greater than 400 nm and equal to or less than 700 nm, and the first detection means may detect the photoluminescence light that has transmitted through the first filter.

[0015] In the above inspection device, the focusing means may further include a second filter disposed between the dichroic mirror and the second detection means, the second filter may include a filter that blocks at least light of a central wavelength of the pulsed light, and the second detection means may detect the Raman scattered light that has transmitted through the second filter.

[0016] In the above inspection device, the second filter may include a filter that blocks light having a wavelength equal to or less than a central wavelength of the pulsed light or equal to or more than a central wavelength of the pulsed light.

[0017] In the above inspection device, the pulsed light may have a wavelength in the visible light region.

[0018] An inspection method according to one aspect of the present embodiment includes a pulsed light generating step of causing a pulsed light generating means to generate pulsed light having a wavelength longer than the wavelength of light corresponding to a band gap of a sample, the pulsed light causing multiphoton excitation of the sample; a focusing step of focusing the pulsed light on the sample with an objective lens and transmitting light including photoluminescence light and Raman scattered light generated from the sample by irradiation with the pulsed light through the objective lens; and a detection step of causing a first detection means to detect the photoluminescence light that has transmitted through the objective lens and a second detection means to detect the Raman scattered light that has transmitted through the objective lens. Equipped with.

[0019] In the above inspection method, the sample may include a semiconductor wafer.

[0020] In the above inspection method, in the focusing step, a half mirror arranged between the objective lens and the second detection means on the optical path of the pulsed light may transmit either the pulsed light or the Raman scattered light and reflect the other, and a first pinhole arranged between the half mirror and the pulsed light generation means, and a second pinhole arranged between the second detection means and the half mirror may detect the Raman scattered light generated from a portion of the sample where the pulsed light is focused, at least in the second detection means.

[0021] In the above inspection method, the half mirror may reflect the pulsed light and transmit the Raman scattered light and the photoluminescence light, or transmit the pulsed light and reflect the Raman scattered light and the photoluminescence light.

[0022] In the above inspection method, in the focusing step, a dichroic mirror disposed between the half mirror and the first detection means and the second detection means may transmit either the photoluminescence light or the Raman scattered light and reflect the other.

[0023] In the above inspection method, the dichroic mirror may reflect or transmit light having a central wavelength of the pulsed light and a surrounding wavelength range of at most ±100 nm, and guide the light having the wavelength range to the second detection means.

[0024] In the above inspection method, in the focusing step, the photoluminescence light that has passed through a first filter disposed between the dichroic mirror and the first detection means and including at least one of a short-pass filter that transmits light with a short wavelength of 400 nm or less, a long-pass filter that transmits light with a wavelength longer than 700 nm, and a band-pass filter that transmits light with a wavelength greater than 400 nm and equal to or less than 700 nm may be detected by the first detection means.

[0025] In the above inspection method, in the focusing step, a second filter may be disposed between the dichroic mirror and the second detection means, and the second detection means may detect the Raman scattered light that has passed through the second filter, the second filter including a filter that blocks at least light of a central wavelength of the pulsed light.

[0026] In the above inspection method, the second filter may further include a filter that blocks light having a wavelength equal to or less than a central wavelength of the pulsed light or equal to or more than a central wavelength of the pulsed light.

[0027] In the above inspection method, the pulsed light may have a wavelength in the visible light region. Effect of the Invention

[0028] According to the present disclosure, it is possible to provide an inspection device and an inspection method that can detect both photoluminescence light and Raman scattered light with a simple configuration and can improve crystal evaluation. [Brief description of the drawings]

[0029] [Figure 1] 1 is a configuration diagram illustrating an inspection device according to a first embodiment. [Diagram 2] FIG. 2 is a flow chart illustrating an inspection method according to the first embodiment. [Diagram 3] FIG. 11 is a configuration diagram illustrating an inspection device according to a second embodiment. [Figure 4]FIG. 11 is a configuration diagram illustrating an inspection device according to a third embodiment. [Diagram 5] 11 is a graph illustrating the transmission characteristics of a dichroic mirror in the inspection device according to the third embodiment, where the horizontal axis indicates wavelength and the vertical axis indicates transmittance. [Figure 6] 11 is a graph illustrating filter characteristics in the inspection device according to the third embodiment, where the horizontal axis indicates wavelength and the vertical axis indicates transmittance. [Figure 7] 10 is a graph illustrating light detected by a first detection means and a second detection means in the inspection device according to the third embodiment, where the horizontal axis indicates wavelength and the vertical axis indicates transmittance. [Figure 8] 10 is a graph illustrating light detected by a first detection means and a second detection means in the inspection device according to the third embodiment, where the horizontal axis indicates wavelength and the vertical axis indicates transmittance. [Figure 9] 10 is a graph illustrating light detected by a first detection means and a second detection means in the inspection device according to the third embodiment, where the horizontal axis indicates wavelength and the vertical axis indicates transmittance. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. The following description shows a preferred embodiment of the present disclosure, and the scope of the present disclosure is not limited to the following embodiment. In the following description, parts with the same reference numerals indicate substantially the same contents.

[0031] (Embodiment 1) An inspection device and an inspection method according to the first embodiment will be described. FIG. 1 is a configuration diagram illustrating an inspection device 1 according to the first embodiment. As shown in FIG. 1, the inspection device 1 according to the present embodiment includes a pulsed light generating means 10, a focusing means 20, and a detection means 30. The inspection device 1 irradiates the sample 40 with pulsed light 11 having a wavelength longer than the wavelength of light corresponding to the band gap of the sample 40, such as a semiconductor wafer. As a result, the inspection device 1 observes the photoluminescence light PL and Raman scattering light RS due to multiphoton excitation caused by the pulsed light 11. In the figure, only the optical axes of the light such as the pulsed light 11, the photoluminescence light PL, and the Raman scattering light RS are shown in a schematic manner. The sample 40 includes, for example, a semiconductor wafer made of a semiconductor material. The semiconductor material may specifically include a wide band gap compound semiconductor such as silicon carbide (SiC) and GaN. However, the sample 40 is not limited to a semiconductor wafer as long as it includes a crystal having a band gap.

[0032] The pulsed light generating means 10 generates pulsed light 11 having a wavelength longer than the wavelength of light corresponding to the band gap of the sample 40. The pulsed light generating means 10 generates the pulsed light 11 that excites the sample 40 with multiphoton excitation.

[0033] In a typical photoluminescence measurement, the sample 40 is irradiated with light having energy greater than the band gap energy of the sample 40. This allows measurement of the photoluminescence light PL emitted when the sample 40 transitions from an excited state to a ground state.

[0034] On the other hand, in the case of photoluminescence measurement by multiphoton excitation, the sample 40 is irradiated with light having about 1 / 2 or 1 / 3 of the energy of the band gap of the sample 40. Then, photoluminescence light PL emitted when the sample 40 transitions from an excited state to a ground state by multiphotons such as two or three photons is measured. Thus, in the case of photoluminescence measurement by multiphoton excitation, pulsed light 11 having a longer wavelength than the wavelength of light corresponding to the band gap of the sample 40 is used. The pulsed light generating means 10 is preferably a femtosecond laser or the like capable of generating the pulsed light 11 with high output. Note that the pulsed light generating means 10 is not limited to a femtosecond laser.

[0035] The specifications of the pulsed light 11 may be, for example, infrared light having a central wavelength of 1040 nm and an output of 3 W or the like. In this case, photoluminescence light PL can be generated by three-photon excitation for a sample 40 such as SiC and GaN. The specifications of the pulsed light 11 may be, for example, visible light having a central wavelength of 520 nm and an output of 1 W or the like. In this case, photoluminescence light PL can be generated by two-photon excitation for a sample 40 such as SiC and GaN. In this way, the wavelength of the pulsed light 11 may include, for example, a wavelength in the infrared light region or a wavelength in the visible light region.

[0036] The focusing means 20 includes an objective lens 21. The focusing means 20 may include other optical members such as a half mirror 22 in addition to the objective lens 21. The focusing means 20 focuses the pulsed light 11 onto the sample 40 with the objective lens 21. The focusing means 20 also transmits light 41 generated from the sample 40 by irradiation with the pulsed light 11 through the objective lens 21. In this way, the focusing means 20 guides the light 41 generated from the sample 40 to the detection means 30. The light 41 generated from the sample 40 includes photoluminescence light PL and Raman scattered light RS. In the figure, the light 41 including the photoluminescence light PL and Raman scattered light RS is indicated as 41(PL, RS).

[0037] The detection means 30 includes a first detection means 31 and a second detection means 32. The first detection means 31 detects the photoluminescence light PL transmitted through the objective lens 21. The first detection means 31 includes a detector capable of detecting the photoluminescence light PL, such as a CCD (Charge Coupled Device) sensor, a TDI (Time Delay Integration) camera, or a PMT (Photomultiplier Tube). The second detection means 32 detects the Raman scattered light RS transmitted through the objective lens 21. The second detection means 32 includes a detector capable of detecting the Raman scattered light RS, such as a CCD or a PMT. The second detection means 32 may further include a spectrometer.

[0038] The first detection means 31 and the second detection means 32 in the detection means 30 may be configured as an integrated unit. For example, the detection means 30 may have the functions of the first detection means 31 and the second detection means 32, and may detect both the photoluminescence light PL and the Raman scattered light RS. Furthermore, the detection means 30 may detect the photoluminescence light PL and the Raman scattered light RS by switching between the first detection means 31 and the second detection means 32 using a switching means.

[0039] Fig. 2 is a flow chart illustrating an inspection method according to embodiment 1. As shown in Fig. 2, the inspection method of this embodiment includes a pulsed light generation step S11, a light collection step S12, and a detection step S13.

[0040] In the pulsed light generation step S11, first, the pulsed light 11 is generated to cause multiphoton excitation of the sample 40. For example, the pulsed light generating means 10 is caused to generate the pulsed light 11 having a wavelength longer than the wavelength of light corresponding to the band gap of the sample 40.

[0041] Next, in the focusing step S12, the pulsed light 11 is focused on the sample 40 by the objective lens 21. At the same time, light 41 generated from the sample 40 by irradiation with the pulsed light 11 is transmitted through the objective lens 21. The light 41 includes photoluminescence light PL and Raman scattered light RS.

[0042] Next, in a detection step S13, the photoluminescence light PL transmitted through the objective lens 21 is detected by the first detection means 31. Also, the Raman scattered light RS transmitted through the objective lens 21 is detected by the second detection means 32.

[0043] Next, the effects of this embodiment will be described. In this embodiment, the sample 40 is excited by multiphoton excitation by irradiating the sample 40 with pulsed light 11 having a wavelength longer than the wavelength of light corresponding to the band gap of the sample 40. This allows both the photoluminescence light PL and the Raman scattered light RS to be detected. The photoluminescence measurement can detect crystal defects in the sample 40. The Raman spectrum measurement can detect internal strain and stress in the sample 40. Therefore, this embodiment can detect not only crystal defects in the sample 40 but also multiple types of internal abnormalities including strain and stress.

[0044] In addition, in this embodiment, the photoluminescence light PL is observed by multiphoton excitation with long wavelength light, and thus simultaneous measurement with the Raman scattered light RS, which is difficult in general photoluminescence measurement using short wavelength light, is performed. This makes it possible to associate the Raman scattered light RS generated at the point where the photoluminescence light PL is generated. Therefore, with a simple configuration, it is possible to detect both the photoluminescence light PL and the Raman scattered light RS, and to improve the crystal evaluation.

[0045] Even if you try to detect the Raman scattered light RS simultaneously with the photoluminescence light PL by combining Raman spectrum measurement based on general photoluminescence measurement, the wavelength bands of the photoluminescence light PL and the Raman scattered light RS are almost the same, and the weaker Raman scattered light RS is buried, making it difficult to detect the Raman scattered light RS with effective resolution. Also, in compound semiconductors such as SiC, ultraviolet light is used as the excitation light for general photoluminescence measurement, so the range of the detector that detects the Raman scattered light RS against ultraviolet light is very narrow, making it very difficult to handle.

[0046] In contrast, in this embodiment, Raman spectrum measurement is combined with photoluminescence measurement using multiphoton excitation. In the photoluminescence measurement using multiphoton excitation, light with a wavelength in the visible light region to the infrared light region is used as excitation light. This solves the above problem.

[0047] Furthermore, since the pulsed light generating means 10 uses a laser light source having a high output necessary for multiphoton excitation, weak Raman scattered light RS can be detected with sufficient intensity and a good S / N ratio. This makes it possible to observe the Raman scattered light RS that allows evaluation of stress inside the crystal. For example, the amount of Stokes shift in Raman spectrum measurement may be expressed by shading, or a reference Stokes wavenumber may be determined and the intensity ratio at that wavenumber may be displayed. The stress inside the sample 40 can be detected by the intensity of the Stokes shift.

[0048] (Embodiment 2) Next, an inspection device according to a second embodiment will be described. In the inspection device of this embodiment, the focusing means 20 includes a confocal optical system. FIG. 3 is a configuration diagram illustrating an inspection device according to the second embodiment. As shown in FIG. 3, in the inspection device 2 of this embodiment, the focusing means 20 further includes a half mirror 22, a first pinhole 23, and a second pinhole 24 in addition to the objective lens 21. Note that the focusing means 20 may further include other optical members in addition to the above members.

[0049] The half mirror 22 is disposed between the objective lens 21 and the second detection means 32 on the optical path of the pulsed light 11. The half mirror 22 transmits either the pulsed light 11 or the Raman scattered light RS and reflects the other. For example, in the inspection device 2 shown in FIG. 3, the half mirror 22 reflects the pulsed light 11 and transmits the light 41 including the Raman scattered light RS. In this case, the half mirror 22 also transmits the light 41 including the photoluminescence light PL. Note that the positions of the pulsed light generation means 10 and the detection means 30 relative to the objective lens 21 may be interchanged so that the half mirror 22 transmits the pulsed light 11 and reflects the light 41 including the Raman scattered light RS. In this case, the half mirror 22 also reflects the light 41 including the photoluminescence light PL.

[0050] The first pinhole 23 is disposed between the half mirror 22 and the pulsed light generating means 10. The second pinhole 24 is disposed between the second detecting means 32 and the half mirror 22. The first pinhole 23 and the second pinhole 24 are disposed so as to form a confocal optical system. That is, at least the second detecting means 32 detects the Raman scattered light RS generated from a portion of the sample 40 where the pulsed light 11 is focused.

[0051] In the inspection method of the present embodiment, in the focusing step S12, the half mirror 22 arranged between the objective lens 21 and the second detection means 32 on the optical path of the pulsed light 11 transmits either the pulsed light 11 or the Raman scattered light RS and reflects the other. The first pinhole 23 arranged between the half mirror 22 and the pulsed light generation means 10, and the second pinhole 24 arranged between the second detection means 32 and the half mirror 22 cause at least the second detection means 32 to detect the Raman scattered light RS generated from the portion of the sample 40 where the pulsed light 11 is focused.

[0052] According to this embodiment, the focusing means 20 forms a confocal optical system. Therefore, the second detection means 32 detects the Raman scattered light RS generated from a portion of the sample 40 on which the pulsed light 11 is focused, and the intensity of the Raman scattered light RS can be increased. In addition, the first detection means 31 detects the photoluminescence light PL generated from a portion of the sample 40 on which the pulsed light 11 is focused. This allows the photoluminescence PL to be associated with the Raman scattered light RS with even higher accuracy, and the crystal evaluation of the sample 40 can be improved.

[0053] (Embodiment 3) Next, an inspection device and an inspection method according to a third embodiment will be described. The inspection device of this embodiment separates the photoluminescence light PL and the Raman scattered light RS by a dichroic mirror. FIG. 4 is a configuration diagram illustrating an inspection device according to the third embodiment. As shown in FIG. 4, the light collecting means 20 in the inspection device 3 of this embodiment further includes a dichroic mirror 25. The light collecting means 20 may further include a filter 27 and a filter 28. The light collecting means 20 may further include other optical members such as a mirror 26 in addition to the above optical members.

[0054] The dichroic mirror 25 is disposed between the half mirror 22 and the first and second detection means 31 and 32. The dichroic mirror 25 transmits either the photoluminescence light PL or the Raman scattered light RS and reflects the other.

[0055] Fig. 5 is a graph illustrating the transmission characteristics of the dichroic mirror 25 in the inspection device 3 according to the third embodiment, where the horizontal axis indicates wavelength and the vertical axis indicates transmittance. As shown in Fig. 5, the dichroic mirror 25 reflects or transmits a wavelength range near the central wavelength of the pulsed light 11, and guides light 41 in the wavelength range to the second detection means 32. The light 41 in the wavelength range includes the pulsed light 11 as well as Raman scattered light RS. The wavelength range is, for example, ±100 nm of the central wavelength of the pulsed light 11. Alternatively, the wavelength range may be, for example, ±50 nm of the central wavelength of the pulsed light 11.

[0056] 4, the dichroic mirror 25 reflects light 41 in a wavelength range including the Raman scattered light RS and transmits the other light 41 including the photoluminescence light PL. The light 41 in a wavelength range including the Raman scattered light RS reflected by the dichroic mirror 25 transmits through the second pinhole 24. The second pinhole 24 is disposed between the dichroic mirror 25 and the second detection means 32. The light 41 transmitted through the second pinhole 24 is reflected by the mirror 26 and enters the filter 28. The filter 28 is disposed between the dichroic mirror 25 and the second detection means 32.

[0057] FIG. 6 is a graph illustrating the characteristics of the filter 28 in the inspection device 3 according to the third embodiment, where the horizontal axis indicates wavelength and the vertical axis indicates transmittance. As shown in FIG. 6, the filter 28 includes a filter that blocks at least light of the central wavelength of the pulsed light 11 for extracting the Raman shift. The filter 28 may include, for example, an edge filter. Specifically, the filter 28 includes a filter that blocks light equal to or less than the central wavelength of the pulsed light 11 or equal to or more than the central wavelength of the pulsed light 11. It is preferable that the second detection means 32 detects the Stokes scattering, which has a high intensity, among the Raman scattered light RS. For this reason, the filter 28 is preferably a filter with long-pass characteristics that blocks light equal to or less than the central wavelength of the pulsed light 11 and transmits light 41 with a wavelength longer than the central wavelength. In this way, the second detection means 32 detects the Raman scattered light RS that has passed through the filter 28. It is preferable that the filter 28 has a switching means for switching between a plurality of filters. The switching means switches the filter according to the wavelength of the Raman scattered light RS to be observed.

[0058] As shown in FIG. 4, light 41 including photoluminescence light PL transmitted through the dichroic mirror 25 enters the filter 27. The filter 27 is disposed between the dichroic mirror 25 and the first detection means 31. The filter 27 includes at least one of a short-pass filter that transmits light with a short wavelength of 400 nm or less, a long-pass filter that transmits light with a wavelength longer than 700 nm, and a band-pass filter that transmits light with a wavelength greater than 400 nm and equal to or less than 700 nm. The filter 27 may have a switching means for switching between a plurality of filters. The switching means switches the filter according to the wavelength of the photoluminescence light PL to be observed.

[0059] 7 to 9 are graphs illustrating wavelength bands of light 41 detected by the first detection means 31 and the second detection means 32 in the inspection device 3 according to the third embodiment, where the horizontal axis indicates wavelength and the vertical axis indicates transmittance, which indicates the intensity of light 41 detected by the first detection means 31 and the second detection means 32. As shown in Fig. 7, the first detection means 31 may detect light 41 transmitted through a short-pass filter that transmits light of a short wavelength of 400 nm or less. In this case, band edge emission of SiC or the like can be observed.

[0060] 8, the first detection means 31 may detect light 41 transmitted through a long-pass filter that transmits light with wavelengths longer than 700 nm. In this case, photoluminescence light PL from basal plane dislocations (BPDs), known as killer defects, present in semiconductor materials such as SIC can be observed.

[0061] 9, the first detection means 31 may detect light 41 transmitted through a bandpass filter that transmits light greater than 400 nm and equal to or less than 700 nm. In this case, photoluminescence light PL such as impurity emission, defect level emission, and stacking fault emission of a wide bandgap semiconductor such as SiC can be observed. In this way, the first detection means 31 detects the photoluminescence light PL transmitted through the filter 27.

[0062] In the inspection method of the present embodiment, in the light collecting step S20, either the photoluminescence light PL or the Raman scattered light RS is transmitted and the other is reflected by the dichroic mirror 25. Furthermore, the photoluminescence light PL transmitted through the filter 27 is detected by the first detection means 31. Furthermore, the Raman scattered light RS transmitted through the filter 28 is detected by the second detection means 32.

[0063] According to this embodiment, the optical path of the photoluminescent light PL detected by the first detection means 31 and the optical path of the Raman scattered light RS detected by the second detection means 32 can be separated by the dichroic mirror 25. Therefore, it is not necessary to configure the optical path of the Raman scattered light RS using a confocal optical system and the optical path of the photoluminescent light PL using a confocal optical system.

[0064] In photoluminescence measurement of multiphoton excitation, the photoluminescence light PL is highly likely to be generated from a portion where the pulsed light 11 is focused, i.e., a portion where the photon density is high. Therefore, the first detection means 31 detects the photoluminescence PL generated from such a portion where the pulsed light 11 is focused. Therefore, even if the first detection means 31 does not have a confocal optical system such as the second pinhole 24, it can substantially detect the photoluminescence light PL generated from the portion where the pulsed light 11 is focused.

[0065] On the other hand, in this embodiment, the second detection means 32 detects the Raman scattered light RS generated from the portion focused by the pulsed light 11 by using a confocal optical system. This makes it possible to associate the photoluminescence PL with the Raman scattered light RS with high accuracy, thereby improving the crystal evaluation of the sample 40.

[0066] In this embodiment, the optical path of the photoluminescent light PL does not need to be configured as a confocal optical system, making it possible to reduce the number of optical members.

[0067] Since the optical path of the photoluminescence light PL and the optical path of the Raman scattering light RS can be separated, different filters 27 and 28 corresponding to the detection targets can be arranged on each optical path. Therefore, it is possible to detect desired wavelength ranges for each of the photoluminescence light PL and the Raman scattering light RS.

[0068] It is desirable that the size of the first pinhole 23 and the second pinhole 24 can be changed. By changing the size of the first pinhole 23 and the second pinhole 24, the size of the portion of the sample 40 where the pulsed light 11 is focused can be changed. Therefore, the size of the observation range of the sample 40 can be changed. For example, by changing the size of the first pinhole 23 and the second pinhole 24 in correspondence with the observation range depending on the occurrence probability of the photoluminescence light PL due to multiphoton excitation, the photoluminescence PL and the Raman scattering light RS can be associated with each other with higher accuracy. In addition, although it has been described that the optical path of the photoluminescence light PL is not configured by a confocal optical system, the optical path of the photoluminescence light PL may also be configured by a confocal optical system like the optical path of the Raman scattering light RS.

[0069] Although the embodiments of the present disclosure have been described above, the present disclosure includes appropriate modifications that do not impair the objects and advantages thereof, and is not limited to the above-mentioned embodiments. In addition, combinations of the configurations of the first to third embodiments are also within the scope of the technical idea of ​​the present disclosure. [Explanation of symbols]

[0070] 1, 2, 3 Inspection equipment 10. Pulsed light generating means 11 Pulsed Light 20 Light collecting means 21 Objective Lens 22 Half Mirror 23 First pinhole 24 2nd pinhole 25 Dichroic mirror 26. Mirror 27 Filters 28 Filters 30 Detection Method 31 First detection means 32 Second detection means 40 Samples 41 light PL photoluminescence light RS Raman scattering light

Claims

1. a pulsed light generating means for generating pulsed light having a wavelength longer than the wavelength of light corresponding to the band gap of the sample, the pulsed light causing multiphoton excitation of the sample; a focusing means including an objective lens, which focuses the pulsed light on the sample with the objective lens, and transmits light including photoluminescence light and Raman scattered light generated from the sample by irradiation with the pulsed light through the objective lens; a first detection means for detecting the photoluminescence light transmitted through the objective lens; a second detection means for detecting the Raman scattered light transmitted through the objective lens; An inspection device equipped with

2. The sample comprises a semiconductor wafer.

2. The inspection device according to claim 1.

3. The light collecting means is a half mirror disposed between the objective lens and the second detection means on an optical path of the pulsed light, the half mirror transmitting one of the pulsed light and the Raman scattered light and reflecting the other; a first pinhole disposed between the half mirror and the pulsed light generating means; a second pinhole disposed between the second detection means and the half mirror; Further comprising: At least the second detection means detects the Raman scattered light generated from a portion of the sample where the pulsed light is focused.

3. The inspection device according to claim 1 or 2.

4. the half mirror reflects the pulsed light and transmits the Raman scattered light and the photoluminescence light, or transmits the pulsed light and reflects the Raman scattered light and the photoluminescence light; 4. The inspection device according to claim 3.

5. the light collecting means further includes a dichroic mirror disposed between the half mirror and the first detection means and the second detection means; the dichroic mirror transmits either the photoluminescence light or the Raman scattered light and reflects the other.

5. The inspection apparatus according to claim 4.

6. the dichroic mirror reflects or transmits light having a central wavelength of the pulsed light and a wavelength range of at least ±100 nm therearound, and guides the light having the wavelength range to the second detection means.

6. The inspection apparatus according to claim 5.

7. the focusing means further includes a first filter disposed between the dichroic mirror and the first detection means, the first filter includes at least one of a short-pass filter that transmits light having a short wavelength of 400 nm or less, a long-pass filter that transmits light having a wavelength longer than 700 nm, and a band-pass filter that transmits light having a wavelength greater than 400 nm and equal to or less than 700 nm; The first detection means detects the photoluminescence light transmitted through the first filter.

6. The inspection apparatus according to claim 5.

8. the focusing means further includes a second filter disposed between the dichroic mirror and the second detection means, the second filter includes a filter that blocks at least light having a central wavelength of the pulsed light, The second detection means detects the Raman scattered light transmitted through the second filter.

6. The inspection apparatus according to claim 5.

9. The second filter includes a filter that blocks light having a wavelength equal to or less than a central wavelength of the pulsed light or equal to or more than a central wavelength of the pulsed light.

9. The inspection apparatus according to claim 8.

10. The wavelength of the pulsed light includes a wavelength in the visible light region.

3. The inspection device according to claim 1 or 2.

11. a pulsed light generating step of causing a pulsed light generating means to generate pulsed light having a wavelength longer than the wavelength of light corresponding to the band gap of the sample, the pulsed light causing multiphoton excitation of the sample; a focusing step of focusing the pulsed light on the sample with an objective lens and transmitting light including photoluminescence light and Raman scattered light generated from the sample by irradiation with the pulsed light through the objective lens; a detection step of causing a first detection means to detect the photoluminescence light transmitted through the objective lens and causing a second detection means to detect the Raman scattered light transmitted through the objective lens; An inspection method comprising:

12. The sample comprises a semiconductor wafer. The inspection method according to claim 11.

13. In the collecting step, a half mirror disposed between the objective lens and the second detection means on the optical path of the pulsed light transmits either the pulsed light or the Raman scattered light and reflects the other light; a first pinhole disposed between the half mirror and the pulsed light generating means, and a second pinhole disposed between the second detecting means and the half mirror, causing at least the second detecting means to detect the Raman scattered light generated from a portion of the sample where the pulsed light is focused; The inspection method according to claim 11 or 12.

14. the half mirror reflects the pulsed light and transmits the Raman scattered light and the photoluminescence light, or transmits the pulsed light and reflects the Raman scattered light and the photoluminescence light; The inspection method according to claim 13.

15. In the collecting step, a dichroic mirror disposed between the half mirror and the first and second detection means transmits either the photoluminescence light or the Raman scattered light and reflects the other. The inspection method according to claim 14.

16. the dichroic mirror reflects or transmits light having a central wavelength of the pulsed light and a wavelength range of at least ±100 nm therearound, and guides the light having the wavelength range to the second detection means. The inspection method according to claim 15.

17. In the collecting step, a first filter is disposed between the dichroic mirror and the first detection means, the first filter including at least one of a short-pass filter that transmits light with a short wavelength of 400 nm or less, a long-pass filter that transmits light with a wavelength longer than 700 nm, and a band-pass filter that transmits light with a wavelength greater than 400 nm and less than 700 nm, and the photoluminescence light transmitted through the first filter is detected by the first detection means; The inspection method according to claim 15.

18. In the collecting step, a second filter disposed between the dichroic mirror and the second detection means, the second detection means detecting the Raman scattered light transmitted through the second filter including a filter that blocks at least light having a central wavelength of the pulsed light; The inspection method according to claim 15.

19. The second filter further includes a filter that blocks light having a wavelength equal to or less than a central wavelength of the pulsed light or equal to or more than a central wavelength of the pulsed light. The inspection method according to claim 18.

20. The wavelength of the pulsed light includes a wavelength in the visible light region. The inspection method according to claim 11 or 12.

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