Method of inspecting a wafer and apparatus for performing the same

Abstract

According to the wafer inspection method, the intensity of incident light can be measured. The difference between the intensity of the incident light and the reference intensity of the reference incident light can be calculated. The incident light can be irradiated onto the wafer. The intensity of the reflected light reflected from the wafer can be measured. The intensity of the reflected light can be corrected based on the difference between the intensity of the incident light and the reference intensity of the reference incident light. Therefore, if a difference occurs between the intensity of the incident light and the reference intensity of the reference incident light, it can be confirmed that a variation has occurred in the intensity of the incident light. By correcting the intensity of the reflected light based on this difference, the reliability of wafer inspection can be significantly improved.

Description

Technology Field

[0001] The present invention relates to a wafer inspection method and an apparatus for performing the same. More specifically, the present invention relates to a method for inspecting a wafer using light and an apparatus for performing the same method. Background Technology

[0002] Generally, multiple wavelengths of light can be used to inspect wafers. For example, light can be irradiated onto a wafer, and the light reflected from the wafer can be detected. Since the detected light contains information about the wafer, the wafer can be inspected based on the detected light.

[0003] According to related technologies, light can be generated from lasers and plasma. Fluctuations may occur in the laser and / or plasma over time. Such fluctuations in the laser and / or plasma can cause variations in light intensity. Variations in light intensity can reduce the reliability of inspection results. Prior art literature

[65535] U.S. Patent Application Publication US2021 / 0082725 The problem to be solved

[0004] The present invention provides a wafer inspection method having improved inspection reliability.

[0005] In addition, the present invention also provides an apparatus for carrying out the above-described method. means of solving the problem

[0006] According to a wafer inspection method according to one aspect of the present invention, the intensity of incident light can be measured. The incident light can be irradiated onto a wafer. The intensity of reflected light reflected from the wafer can be measured. The intensity of the reflected light can be corrected based on the difference between the intensity of the incident light and the reference intensity of the reference incident light.

[0007] A wafer inspection device according to another aspect of the present invention may include a light source, a first measuring unit, a second measuring unit, and a correction unit. The light source may generate incident light for inspecting a wafer. The first measuring unit may measure the intensity of the incident light. The first measuring unit may determine the difference between the intensity of the incident light and the reference intensity of the reference incident light. The second measuring unit may measure the intensity of the reflected light reflected from the wafer. The correction unit may correct the intensity of the reflected light based on the difference between the intensity of the incident light and the reference intensity of the reference incident light. Effects of the invention

[0008] According to the present invention described above, if a difference occurs between the intensity of the incident light and the reference intensity of the reference incident light, it can be confirmed that a variation has occurred in the intensity of the incident light. By correcting the intensity of the reflected light based on this difference, the reliability of wafer inspection can be significantly improved. Brief explanation of the drawing

[0009] FIG. 1 is a block diagram showing a wafer inspection device according to one embodiment of the present invention. Figure 2 is a flowchart sequentially illustrating a method of inspecting a wafer using the device shown in Figure 1. FIG. 3 is a block diagram showing a wafer inspection device according to another embodiment of the present invention. Figure 4 is a flowchart sequentially illustrating a method of inspecting a wafer using the device shown in Figure 3. FIG. 5 is a block diagram showing a wafer inspection device according to another embodiment of the present invention. FIG. 6 is a flowchart sequentially illustrating a method of inspecting a wafer using the device illustrated in FIG. 5. Specific details for implementing the invention

[0010] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

[0011] FIG. 1 is a block diagram showing a wafer inspection device according to one embodiment of the present invention.

[0012] Referring to FIG. 1, a wafer inspection device (100) according to the present embodiment may include a light source (110), a polarization state generator (PSA) (120), a beam splitter (130), a first spectrometer (140), a first calibrator (142), a polarization state analyzer (150), a second spectrometer (160), a second calibrator (162), and a corrector (170).

[0013] A light source (110) can generate incident light (I0) for inspecting a wafer (W). The light source (110) may be positioned on the upper left side of the wafer (W), but may not be limited to a specific location. In this embodiment, the incident light (I0) may have multiple wavelengths.

[0014] A polarization state generating unit (120) may be positioned between a light source (110) and a wafer (W). The polarization state generating unit (120) may include a polarizer, a compensator, etc. The polarization state generating unit (120) may polarize the incident light (I0) to impart optical characteristics to the incident light (I0) that meet the wafer (W) inspection conditions.

[0015] A beam splitter (130) may be positioned between a light source (110) and a polarization state generating unit (120). The beam splitter (130) may split the incident light (I0) into a first split light (I1) and a second split light (I2). The first split light (I1) may be irradiated onto a wafer (W) through the polarization state generating unit (120).

[0016] The second split light (I2) can be incident on the first spectrometer (140). The first spectrometer (140) can spectrally separate the second split light (I2) by wavelength. The first spectrometer (140) may include a first measuring unit (142). That is, the first measuring unit (142) may be built into the first spectrometer (140). The first measuring unit (142) may include an area sensor, but is not limited thereto.

[0017] The first measuring unit (142) can measure the wavelength-specific intensity of the second split light (I2). Since the second split light is split from the incident light (I0), the wavelength-specific intensity of the second split light (I2) measured by the first measuring unit (142) may correspond to the wavelength-specific intensity of the incident light (I0). Additionally, the first measuring unit (142) can measure the wavelength-specific intensity of the reference incident light. The reference incident light may have a wavelength-specific reference intensity set during the wafer (W) inspection process. The wavelength-specific intensity of the incident light (I0) measured by the first measuring unit (142) and the wavelength-specific reference intensity of the reference incident light may be transmitted to the correction unit (170).

[0018] The first split light (I1) split from the incident light (I0) will also have the same wavelength intensity as the second split light (I2). After the first split light (I1) is incident on the wafer (W), it can be reflected from the wafer (W) to form reflected light (R).

[0019] Reflected light (R) can be incident on a polarization state analysis unit (150). The polarization state analysis unit (150) may include a polarizer, a compensator, etc. The polarization state analysis unit (150) can analyze the reflected light (R). In particular, the polarization state analysis unit (150) can polarize the reflected light (R) to convert the reflected light (R) into a readable state.

[0020] The reflected light (R) that has passed through the polarization state analysis unit (150) can be incident on the second spectrometer (160). The second spectrometer (160) can spectrally analyze the reflected light (R) by wavelength. The second spectrometer (160) may include a second measurement unit (162). That is, the second measurement unit (162) may be built into the second spectrometer (160). The second measurement unit (162) may include an area sensor, but is not limited thereto.

[0021] The second measuring unit (162) can measure the wavelength-dependent intensity of the reflected light (R). The reflected light (R) reflected from the wafer (W) may contain information about the wafer (W), for example, information about the profile of a pattern formed on the wafer (W). Therefore, the wavelength-dependent intensity of the reflected light (R) may represent information about the wafer (W). For example, an image of the wafer (W) can be obtained from the wavelength-dependent intensity of the reflected light (R).

[0022] Additionally, the second measuring unit (162) can measure the wavelength-specific intensity of the reference reflected light. Since the reference reflected light is formed from the reference incident light incident on the wafer (W), the reference reflected light may have a wavelength-specific reference intensity set during the wafer (W) inspection process. The wavelength-specific intensity of the reflected light (R) measured by the second measuring unit (162) and the wavelength-specific reference intensity of the reference reflected light can be transmitted to the correction unit (170).

[0023] The correction unit (170) can correct the wavelength-specific intensity of the reflected light (R). For example, if the wavelength-specific intensity of the reflected light (R) is represented as an image, the correction unit (170) can correct the gray level on the image.

[0024] Specifically, the correction unit (170) can compare the wavelength-specific intensity of the incident light (I0) with the wavelength-specific reference intensity of the reference incident light. If no change occurs in the incident light (I0) over time, the wavelength-specific intensity of the incident light (I0) measured by the first measurement unit (142) will be the same as the wavelength-specific reference intensity of the reference incident light. On the other hand, if a change occurs in the incident light (I0) over time, the wavelength-specific intensity of the incident light (I0) measured by the first measurement unit (142) will be different from the wavelength-specific reference intensity of the reference incident light. This difference in intensity may appear as a change in the spectrum. The correction unit (170) can calculate the difference between the wavelength-specific intensity of the incident light (I0) and the wavelength-specific reference intensity of the reference incident light.

[0025] Additionally, the correction unit (170) can compare the wavelength-specific intensity of the measured reflected light (R) with the wavelength-specific reference intensity of the reference reflected light. If no change occurs in the incident light (I0) over time, the reflected light (R) will have the same characteristics as the reference reflected light. Therefore, the wavelength-specific intensity of the reflected light (R) measured by the second measurement unit (162) will be the same as the wavelength-specific reference intensity of the reference reflected light. On the other hand, if a change occurs in the incident light (I0) over time, the reflected light (R) will have characteristics different from those of the reference reflected light. Therefore, the wavelength-specific intensity of the reflected light (R) measured by the second measurement unit (162) will be different from the wavelength-specific reference intensity of the reference reflected light. The correction unit (170) can calculate the difference between the wavelength-specific intensity of the reflected light (R) and the wavelength-specific reference intensity of the reference reflected light.

[0026] The correction unit (170) can perform the following methods to correct the wavelength-specific intensity of the reflected light (R). The correction unit (170) can obtain the difference between the intensity of the incident light (I0) and the reference intensity of the reference incident light. The correction unit (170) can obtain the ratio of the intensity of the reflected light to the intensity of the incident light (I0). The correction unit (170) can obtain the difference between the wavelength-specific intensity of the reflected light (R) and the wavelength-specific reference intensity of the reference reflected light by multiplying the ratio by the difference between the intensity of the incident light (I0) and the reference intensity of the reference incident light. The correction unit (170) can correct the wavelength-specific intensity of the reflected light (R) by adding the difference between the intensity of the reflected light (R) and the reference intensity of the reference reflected light to the intensity of the reflected light (R).

[0027] Figure 2 is a flowchart sequentially illustrating a method of inspecting a wafer using the device shown in Figure 1.

[0028] Referring to FIGS. 1 and FIGS. 2, in step ST400, a light source (110) can generate reference incident light having a reference intensity (S0).

[0029] In step ST402, the beam splitter (130) can split the reference incident light into a first reference split light and a second reference split light. The first reference split light can be incident on the polarization state generating unit (120). The second reference split light can be incident on the first spectrometer (140).

[0030] In step ST404, the first spectrometer (140) can spectroscopically analyze the second reference split light. The first measuring unit (142) can measure the wavelength-specific reference intensity (X0) of the second reference split light. The measured wavelength-specific reference intensity (X0) of the second reference split light can be transmitted to the correction unit (170).

[0031] In step ST406, the polarization state generating unit (120) polarizes the first reference split light so that optical characteristics corresponding to the wafer (W) inspection conditions can be imparted to the first reference split light.

[0032] In step ST408, a first reference split light may be irradiated onto the wafer (W). The first reference split light may be reflected from the wafer (W) to form a reference reflected light. The reference reflected light may have a reference intensity (Y0).

[0033] In step ST410, the polarization state analysis unit (150) can analyze the reference reflected light.

[0034] In step ST412, the second spectrometer (160) can spectrally analyze the reference reflected light. The second measuring unit (162) can measure the wavelength-specific reference intensity (Y0) of the reference reflected light. The measured wavelength-specific reference intensity (Y0) of the reference reflected light can be transmitted to the correction unit (170).

[0035] After a predetermined amount of time has elapsed, the light source (110) may change. In this case, at step ST414, the light source (110) may generate incident light (I0). The incident light (I0) may have an intensity (S1) different from the reference intensity (S0) of the reference incident light.

[0036] In step ST416, a beam splitter (130) can split the incident light (I0) into a first split light (I1) and a second split light (I2). The first split light (I1) can be incident on a polarization state generating unit (120). The second split light (I2) can be incident on a first spectrometer (140).

[0037] In step ST418, the first spectrometer (140) can spectroscopically analyze the second split light (I2). The first measuring unit (142) can measure the wavelength-dependent intensity (X1) of the second split light (I2). The measured wavelength-dependent reference intensity (X1) of the second split light (I2) can be transmitted to the correction unit (170).

[0038] In step ST420, the polarization state generating unit (120) can polarize the first split light (I1) to impart optical characteristics to the first split light (I1) that correspond to the wafer (W) inspection conditions.

[0039] In step ST422, a first split light (I1) may be irradiated onto a wafer (W). The first split light (I1) may be reflected from the wafer (W) to form reflected light (R). The reflected light (R) may have a different intensity (Y1) from the wavelength-dependent reference intensity (Y0) of the reference reflected light.

[0040] In step ST424, the polarization state analysis unit (150) can analyze the reflected light (R).

[0041] In step ST426, the second spectrometer (160) can spectrally analyze the reflected light (R). The second measuring unit (162) can measure the wavelength-dependent intensity (Y1) of the reflected light (R). The measured wavelength-dependent intensity (Y1) of the reflected light (R) can be transmitted to the correction unit (170).

[0042] In step ST428, the correction unit (170) can compare the wavelength-specific intensity (X1) of the second split light (I2) with the wavelength-specific reference intensity (X0) of the reference incident light to obtain the difference (ΔX) between the wavelength-specific intensity (X1) of the second split light (I2) and the wavelength-specific reference intensity (X0) of the reference incident light. Additionally, the correction unit (170) can compare the wavelength-specific intensity (Y1) of the measured reflected light (R) with the wavelength-specific reference intensity (Y0) of the reference reflected light to obtain the difference (ΔY) between the wavelength-specific intensity (Y1) of the reflected light (R) and the wavelength-specific reference intensity (Y0) of the reference reflected light.

[0043] Here, the following relationships can be established between the reference intensity of the reference incident light (S0), the wavelength-specific reference intensity of the second reference split light (X0), the reference intensity of the reference reflected light (Y0), the intensity of the incident light (I0) (S0), the wavelength-specific intensity of the second split light (I2) (X1), and the wavelength-specific intensity of the reflected light (R) (Y1).

[0044] X0 / S0 = X1 / S O (1+f1), f1 = ΔX / X0, ΔX = X1-X0

[0045] Y0 / S0= Y1 / S0(1+f2), f2 = ΔY / Y0, ΔY = Y1-Y0

[0046] ΔY = (Y0 / X0)ΔX, Y0= (X0 / X1)Y1, ΔY = (Y1 / X1)Δ X

[0047] Based on the above equations, the correction value (Yc) of the wavelength-specific intensity of the reflected light (R) can be obtained from the following equation.

[0048] Yc = Y1 + ΔY

[0049] That is, the correction unit (170) calculates the difference between the intensity (X1) of the incident light (I0) corresponding to the second reference split light and the reference intensity (X0) of the reference incident light, calculates the ratio of the intensity (Y1) of the reflected light (R) to the intensity (X1) of the incident light (I0), and then multiplies this ratio by the difference (ΔX) between the intensity (X1) of the incident light (I0) and the reference intensity (X0) of the reference incident light to obtain the difference (ΔY) between the wavelength-specific intensity (Y1) of the reflected light (R) and the wavelength-specific reference intensity (Y0) of the reference reflected light, and by adding this difference (ΔY) to the intensity (Y1) of the reflected light (R), the wavelength-specific intensity of the reflected light (R) can be corrected.

[0050] FIG. 3 is a block diagram showing a wafer inspection device according to another embodiment of the present invention.

[0051] Referring to FIG. 3, the wafer inspection device (200) according to the present embodiment may include a light source (210), a spectrometer (240), a polarization state generating unit (220), a beam splitter (230), a first measurement unit (242), a polarization state analysis unit (250), a second measurement unit (262), and a correction unit (270).

[0052] The light source (210) can generate incident light (I0) for inspecting the wafer (W). The light source (210) may be positioned on the upper left side of the wafer (W), but may not be limited to a specific location. In this embodiment, the incident light (I0) may have multiple wavelengths.

[0053] A spectrometer (240) can be placed between the light source (210) and the wafer (W). The spectrometer (240) can spectrally separate the incident light (I0) by wavelength.

[0054] The polarization state generating unit (220) may be positioned between the spectrometer (240) and the wafer (W). The polarization state generating unit (220) may include a polarizer, a compensator, etc. The polarization state generating unit (220) may polarize the incident light (I0) to impart optical characteristics to the incident light (I0) that meet the wafer (W) inspection conditions.

[0055] A beam splitter (230) may be positioned between a spectrometer (240) and a polarization state generator (220). The beam splitter (130) may split the spectrally split incident light (I0) into a first split light (I1) and a second split light (I2). The first split light (I1) may be irradiated onto a wafer (W) through the polarization state generator (220).

[0056] The second split light (I2) can be incident on the first measuring unit (242). The first measuring unit (242) can measure the wavelength-specific intensity of the second split light (I2). Additionally, the first measuring unit (242) can measure the wavelength-specific intensity of the reference incident light. The wavelength-specific intensity of the second split light (I2) and the wavelength-specific reference intensity of the reference incident light measured by the first measuring unit (242) can be transmitted to the correction unit (270).

[0057] After the first split light (I1) is incident on the wafer (W), it may be reflected from the wafer (W) to form reflected light (R). The reflected light (R) may be incident on the polarization state analysis unit (250). The polarization state analysis unit (250) may include a polarizer, a compensator, etc. The polarization state analysis unit (250) may analyze the reflected light (R). For example, the polarization state analysis unit (250) may polarize the reflected light (R) to convert the reflected light (R) into a readable state.

[0058] The reflected light (R) that has passed through the polarization state analysis unit (250) can be incident on the second measurement unit (262). The second measurement unit (262) can measure the wavelength-dependent intensity of the reflected light (R). The reflected light (R) reflected from the wafer (W) may contain information about the wafer (W), for example, information about the profile of the pattern formed on the wafer (W). Therefore, the wavelength-dependent intensity of the reflected light (R) can represent information about the wafer (W). For example, an image of the wafer (W) can be obtained from the wavelength-dependent intensity of the reflected light (R).

[0059] Additionally, the second measuring unit (262) can measure the wavelength-specific intensity of the reference reflected light. Since the reference reflected light is reflected from the wafer (W) into which the reference incident light is incident, the reference reflected light may have a wavelength-specific reference intensity set during the wafer (W) inspection process. The wavelength-specific intensity of the reflected light (R) measured by the second measuring unit (262) and the wavelength-specific reference intensity of the reference reflected light can be transmitted to the correction unit (270).

[0060] The correction unit (270) can correct the wavelength-specific intensity of the reflected light (R). The correction function of the correction unit (270) may be substantially the same as the function of the correction unit (170) shown in FIG. 1. Therefore, the repetition of the correction function of the correction unit (270) may be omitted.

[0061] Figure 4 is a flowchart sequentially illustrating a method of inspecting a wafer using the device shown in Figure 3.

[0062] Referring to FIGS. 3 and FIGS. 4, in step ST500, a light source (210) can generate reference incident light having a reference intensity.

[0063] In step ST502, the spectrometer (240) can spectroscopically analyze the reference incident light.

[0064] In step ST504, the beam splitter (230) can split the spectrally split reference incident light into a first reference split light and a second reference split light. The first reference split light can be incident on the polarization state generating unit (220). The second reference split light can be incident on the first measurement unit (242).

[0065] In step ST506, the first measuring unit (242) can measure the wavelength-specific reference intensity of the second reference split light. The measured wavelength-specific reference intensity of the second reference split light can be transmitted to the correction unit (270).

[0066] In step ST508, the polarization state generating unit (220) polarizes the first reference split light so that optical characteristics corresponding to the wafer (W) inspection conditions can be imparted to the first reference split light.

[0067] In step ST510, a first reference split light may be irradiated onto the wafer (W). The first reference split light may be reflected from the wafer (W) to form a reference reflected light. The reference reflected light may have a reference intensity.

[0068] In step ST512, the polarization state analysis unit (250) can analyze the reference reflected light.

[0069] In step ST514, the second measuring unit (262) can measure the reference intensity of the reference reflected light by wavelength. The measured reference intensity of the reference reflected light by wavelength can be transmitted to the correction unit (270).

[0070] After a predetermined amount of time has elapsed, the light source (210) may change. In this case, in step ST516, the light source (210) may generate incident light (I0). The incident light (I0) may have an intensity different from the reference intensity of the reference incident light.

[0071] In step ST518, the spectrometer (240) can spectroscopically analyze the incident light (I0).

[0072] In step ST520, a beam splitter (230) can split the spectrally split incident light (I0) into a first split light (I1) and a second split light (I2). The first split light (I1) can be incident on a polarization state generating unit (220). The second split light (I2) can be incident on a first measurement unit (242).

[0073] In step ST522, the first measuring unit (242) can measure the wavelength-dependent intensity of the second split light (I2). The measured wavelength-dependent intensity of the second split light (I2) can be transmitted to the correction unit (270).

[0074] In step ST524, the polarization state generating unit (220) can polarize the first split light (I1) to impart optical characteristics to the first split light (I1) that correspond to the wafer (W) inspection conditions.

[0075] In step ST526, a first split light (I1) may be irradiated onto a wafer (W). The first split light (I1) may be reflected from the wafer (W) to form reflected light (R). The reflected light (R) may have a different intensity from the wavelength-specific reference intensity of the reference reflected light.

[0076] In step ST528, the polarization state analysis unit (250) can analyze the reflected light (R).

[0077] In step ST530, the second measuring unit (262) can measure the wavelength-dependent intensity of the reflected light (R). The measured wavelength-dependent intensity of the reflected light (R) can be transmitted to the correction unit (270).

[0078] In step ST532, the correction unit (270) can correct the wavelength-specific intensity of the reflected light (R) using the wavelength-specific reference intensity of the second reference split light, the wavelength-specific reference intensity of the reference reflected light, the wavelength-specific intensity of the second split light (I2), and the wavelength-specific intensity of the reflected light (R). Since the correction operation of the correction unit (270) is substantially the same as the correction operation of the correction unit (170) described in FIG. 2, a repeated explanation of the correction operation of the correction unit (270) may be omitted.

[0079] FIG. 5 is a block diagram showing a wafer inspection device according to another embodiment of the present invention.

[0080] Referring to FIG. 5, the wafer inspection device (300) according to the present embodiment may include a light source (310), a polarization state generating unit (320), a beam splitter (330), a first measuring unit (342), a polarization state analysis unit (350), a second measuring unit (362), and a correction unit (370).

[0081] The light source (310) can generate incident light (I0') for inspecting the wafer (W). The light source (310) may be positioned on the upper left side of the wafer (W), but may not be limited to a specific location. In this embodiment, the incident light (I0') may have a single wavelength. Therefore, the wafer inspection device (300) of this embodiment may not include a spectrometer for spectrally analyzing the incident light (I0').

[0082] A polarization state generating unit (320) may be positioned between a light source (310) and a wafer (W). The polarization state generating unit (320) may include a polarizer, a compensator, etc. The polarization state generating unit (320) may polarize the incident light (I0') to impart optical characteristics to the incident light (I0') that meet the wafer (W) inspection conditions.

[0083] A beam splitter (330) may be positioned between a light source (310) and a polarization state generating unit (320). The beam splitter (330) may split incident light (I0') into a first split light (I1') and a second split light (I2'). The first split light (I1') may be irradiated onto a wafer (W) through the polarization state generating unit (320).

[0084] The second split light (I2') can be incident on the first measuring unit (342). The first measuring unit (342) can measure the intensity of the second split light (I2'). Additionally, the first measuring unit (342) can measure the intensity of the reference incident light. The intensity of the second split light (I2') and the reference intensity of the reference incident light measured by the first measuring unit (342) can be transmitted to the correction unit (370).

[0085] After the first split light (I1') is incident on the wafer (W), it may be reflected from the wafer (W) to form reflected light (R'). The reflected light (R') may be incident on the polarization state analysis unit (350). The polarization state analysis unit (350) may include a polarizer, a compensator, etc. The polarization state analysis unit (350) may analyze the reflected light (R').

[0086] The reflected light (R') that has passed through the polarization state analysis unit (350) can be incident on the second measurement unit (362). The second measurement unit (362) can measure the intensity of the reflected light (R'). The reflected light (R') reflected from the wafer (W) may contain information about the wafer (W), for example, information about the profile of the pattern formed on the wafer (W). Therefore, the intensity of the reflected light (R') may represent information about the wafer (W). For example, an image of the wafer (W) can be obtained from the intensity of the reflected light (R').

[0087] Additionally, the second measuring unit (362) can measure the intensity of the reference reflected light. Since the reference reflected light is reflected from the wafer (W) into which the reference incident light is incident, the reference reflected light may have a reference intensity set during the wafer (W) inspection process. The intensity of the reflected light (R') measured by the second measuring unit (362) and the reference intensity of the reference reflected light can be transmitted to the correction unit (370).

[0088] The correction unit (370) can correct the intensity of the reflected light (R'). The correction function of the correction unit (370) may be substantially the same as the function of the correction unit (170) shown in FIG. 1. Therefore, a repeated description of the correction function of the correction unit (370) may be omitted.

[0089] FIG. 6 is a flowchart sequentially illustrating a method of inspecting a wafer using the device illustrated in FIG. 5.

[0090] Referring to FIGS. 5 and FIGS. 6, in step ST600, a light source (310) can generate reference incident light having a reference intensity. The reference incident light may have a single wavelength.

[0091] In step ST602, the beam splitter (330) can split the reference incident light into a first reference split light and a second reference split light. The first reference split light can be incident on the polarization state generating unit (320). The second reference split light can be incident on the first measurement unit (342).

[0092] In step ST604, the first measuring unit (342) can measure the reference intensity of the second reference split light. The measured reference intensity of the second reference split light can be transmitted to the correction unit (370).

[0093] In step ST606, the polarization state generating unit (320) polarizes the first reference split light so that optical characteristics corresponding to the wafer (W) inspection conditions can be imparted to the first reference split light.

[0094] In step ST608, a first reference split light may be irradiated onto the wafer (W). The first reference split light may be reflected from the wafer (W) to form a reference reflected light. The reference reflected light may have a reference intensity.

[0095] In step ST610, the polarization state analysis unit (350) can analyze the reference reflected light.

[0096] In step ST612, the second measuring unit (362) can measure the reference intensity of the reference reflected light. The measured reference intensity of the reference reflected light can be transmitted to the correction unit (370).

[0097] After a predetermined amount of time has elapsed, the light source (310) may be changed. In this case, at step ST614, the light source (310) may generate incident light (I0') having a single wavelength. The incident light (I0') may have an intensity different from the reference intensity of the reference incident light.

[0098] In step ST616, a beam splitter (330) can split the incident light (I0') into a first split light (I1') and a second split light (I2'). The first split light (I1') can be incident on a polarization state generating unit (320). The second split light (I2') can be incident on a first measuring unit (342).

[0099] In step ST618, the first measuring unit (342) can measure the intensity of the second split light (I2'). The measured intensity of the second split light (I2') can be transmitted to the correction unit (370).

[0100] In step ST620, the polarization state generating unit (320) can polarize the first split light (I1') to impart optical characteristics to the first split light (I1') that meet the wafer (W) inspection conditions.

[0101] In step ST622, a first split light (I1') may be irradiated onto a wafer (W). The first split light (I1') may be reflected from the wafer (W) to form reflected light (R'). The reflected light (R') may have an intensity different from the reference intensity of the reference reflected light.

[0102] In step ST624, the polarization state analysis unit (350) can analyze the reflected light (R').

[0103] In step ST626, the second measuring unit (362) can measure the intensity of the reflected light (R'). The measured intensity of the reflected light (R') can be transmitted to the correction unit (370).

[0104] In step ST628, the correction unit (370) can correct the intensity of the reflected light (R') using the reference intensity of the second reference split light, the reference intensity of the reference reflected light, the intensity of the second split light (I2'), and the intensity of the reflected light (R'). Since the correction operation of the correction unit (370) is substantially the same as the correction operation of the correction unit (170) described in FIG. 2, a repeated explanation of the correction operation of the correction unit (370) may be omitted.

[0105] According to the embodiments described above, if a difference occurs between the intensity of the incident light and the reference intensity of the reference incident light, it can be confirmed that a variation has occurred in the intensity of the incident light. By correcting the intensity of the reflected light based on this difference, the reliability of wafer inspection can be significantly improved.

[0106] As described above, although the present invention has been explained with reference to preferred embodiments, those skilled in the art will understand that various modifications and changes can be made to the invention without departing from the spirit of the invention as set forth in the following claims. Explanation of the symbols

[0107] 110 ; Light source 120 ; Polarization state generator 130 ; Beam splitter 140 ; ​​First spectrometer 142 ; 1st measurement unit 150 ; Polarization state analysis unit 160 ; 2nd spectrometer 162 ; 2nd measuring unit 170 ; Correction section 210 ; Light source 220 ; Polarization state generator 230 ; Beam splitter 240 ; Spectrometer 242 ; First measuring unit 250 ; Polarization state analysis unit 262 ; Second measurement unit 270 ; Correction section 310 ; Light source 320 ; Polarization state generator 330 ; Beam splitter 342 ; 1st Measurement Unit 350 ; Polarization State Analysis Unit 362 ; 2nd measuring unit 370 ; Correction unit

Claims

Claim 1 A wafer inspection method comprising: generating a reference incident light having multiple wavelengths; dividing the reference incident light into a first reference split light and a second reference split light; measuring the wavelength-specific reference intensity of the second reference split light; irradiating the first reference split light onto a wafer to form a reference reflected light; measuring the wavelength-specific reference intensity of the reference reflected light; measuring the wavelength-specific intensity of the incident light having multiple wavelengths; irradiating the incident light onto a wafer; measuring the wavelength-specific intensity of the reflected light reflected from the wafer; and correcting the wavelength-specific intensity of the reflected light based on the difference between the wavelength-specific intensity of the incident light and the wavelength-specific reference intensity of the second reference split light, wherein the incident light corresponds to light generated from a light source that has changed after a predetermined time has elapsed since the reference incident light was generated. Claim 2 delete Claim 3 A wafer inspection method according to claim 1, wherein measuring the wavelength-dependent intensity of the incident light comprises dividing a portion of the incident light; spectrally separating the divided incident light by wavelength; and measuring the wavelength-dependent intensity of the spectrally separated incident light, and measuring the wavelength-dependent intensity of the reflected light comprises spectrally separating the reflected light by wavelength; and measuring the wavelength-dependent intensity of the spectrally separated reflected light. Claim 4 A wafer inspection method according to claim 1, wherein measuring the wavelength-dependent intensity of the incident light comprises spectrally splitting the incident light by wavelength; splitting a portion of the spectrally split incident light; and measuring the wavelength-dependent intensity of the split incident light, and measuring the wavelength-dependent intensity of the reflected light comprises irradiating the split incident light onto the wafer; and measuring the wavelength-dependent intensity of the reflected light reflected from the wafer. Claim 5 A wafer inspection method according to claim 1, wherein correcting the intensity of the reflected light comprises calculating the difference between the wavelength-specific intensity of the reflected light and the wavelength-specific reference intensity of the reference reflected light; and summing the difference between the wavelength-specific intensity of the reflected light and the wavelength-specific reference intensity of the reference reflected light to the wavelength-specific intensity of the reflected light, and calculating the difference between the wavelength-specific intensity of the reflected light and the wavelength-specific reference intensity of the reference reflected light comprises calculating the difference between the wavelength-specific intensity of the incident light and the wavelength-specific reference intensity of the second reference split light; calculating the ratio of the wavelength-specific intensity of the reflected light to the wavelength-specific intensity of the incident light; and multiplying the ratio by the difference between the wavelength-specific intensity of the incident light and the wavelength-specific reference intensity of the reference incident light. Claim 6 A wafer inspection device comprising: a light source that generates incident light having multiple wavelengths and reference incident light having multiple wavelengths for inspecting a wafer; a beam splitter disposed between the light source and the wafer, which splits the incident light into a first incident light and a second incident light, and splits the reference incident light into a first reference incident light and a second reference incident light; a first measuring unit that measures the wavelength-specific intensity of the second incident light and the wavelength-specific intensity of the second reference incident light; a second measuring unit that measures the wavelength-specific intensity of the reflected light reflected from the wafer by the first incident light and the wavelength-specific intensity of the reference reflected light reflected from the wafer by the first reference incident light; and a correction unit that corrects the wavelength-specific intensity of the reflected light based on the difference between the intensity of the incident light and the reference intensity of the reference incident light, wherein the incident light corresponds to light generated from a light source that has changed after a predetermined time has elapsed since the reference incident light was generated. Claim 7 delete Claim 8 A wafer inspection device according to claim 6, further comprising: a first spectrometer having a built-in first measuring unit that spectrally separates the second incident light and the second reference incident light split by the beam splitter according to wavelength; and a second spectrometer having a built-in second measuring unit that spectrally separates the reflected light and the reference reflected light according to wavelength. Claim 9 A wafer inspection device according to claim 6, further comprising a spectrometer disposed between the light source and the wafer to spectrally separate the incident light and the reference incident light by wavelength, wherein the beam splitter disposed between the spectrometer and the wafer to split the spectrally separated incident light and the spectrally separated reference incident light and introduce them to the first measurement unit. Claim 10 A wafer inspection device according to claim 6, wherein the correction unit calculates the difference between the intensity of the incident light and the reference intensity of the reference incident light, calculates the ratio of the intensity of the reflected light to the intensity of the incident light, multiplies the ratio by the difference between the intensity of the incident light and the reference intensity of the reference incident light to calculate the difference between the intensity of the reflected light and the reference intensity of the reference reflected light, and sums the difference between the intensity of the reflected light and the reference intensity of the reference reflected light to the intensity of the reflected light.

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