Semiconductor measurement device

Abstract

To provide a semiconductor measurement device capable of improving measurement accuracy.SOLUTION: A semiconductor measurement device 1 according to an embodiment includes: a laser light source 10 that generates a fundamental wave P1 with a first wavelength; an objective lens 26 that focuses the fundamental wave P1 onto a sample surface 41; a wavelength filter 27 that separates reflected light R1 obtained from reflection of the fundamental wave P1 by the sample 40 and signal light L2 being the signal light L2 which is generated when the fundamental wave P1 is radiated to the sample 40 and having a second wavelength different from the first wavelength; and a detection unit 30 that detects the signal light L2 separated by the wavelength filter 27. The detection unit 30 is arranged to detect the signal light L2 generated by the same fundamental wave P1 in two or more different emission directions from the sample 40.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to semiconductor metrology equipment. [Background technology]

[0002] In semiconductor device manufacturing, up until about 20 years ago, miniaturization of circuit patterns was the only axis of evolution, which not only improved driving speed and reduced power consumption, but also reduced costs. However, the technical difficulty of miniaturization has increased, and in recent years, the contribution of performance improvement through control of physical properties, such as the introduction of new materials such as high-K and low-K, and the intentional addition of strain to improve electron mobility, in addition to the three-dimensional structuring of devices, has been particularly high.

[0003] Due to these factors, high-precision, high-throughput physical property measurements are becoming essential for both process development in research and development and yield improvement in mass production. Examples include measurements of the amount and spatial distribution of dopants in ion implantation processes, the reactivation state after annealing, and the amount of internal strain in the selective epitaxial growth process of silicon germanium (SiGe).

[0004] However, it is difficult to evaluate these physical properties using physical measuring devices such as OCD (Optical Critical Dimension) and CD-SEM (Critical Dimension-Scanning Electron Microscope). Chemical measuring methods using X-ray fluorescence and mass spectrometry are acceptable in terms of accuracy, but have problems with throughput. In addition, chemical measuring methods are often destructive tests.

[0005] In contrast, another approach, electrical characteristic testing, is the testing of transistors with a MOS (Metal-Oxide-Silicon) structure, which is a basic component. This transistor testing involves electrically connecting a probe to evaluate electrical characteristics such as CV characteristics. This is a direct performance evaluation of semiconductor devices. Transistor testing such as LADA (Laser-Assisted Device Alteration) and OBIRCH (Optical Beam Induced Resistance CHange) uses light to not only confirm defects, but also identify the margin for defects and the location of high resistance within the device.

[0006] However, since all of the measurements are contact-type, these tests are only possible in the post-semiconductor manufacturing process where wiring layers and pads are formed. If these electrical characteristic evaluations could be confirmed in a non-contact manner in the pre-semiconductor manufacturing process, and the results could be used to accurately analyze the spread of the depletion layer and inversion region formed inside the semiconductor, then it would be possible to quickly feed back information to processes such as ion implantation and annealing, which would be extremely effective in shortening development periods and manufacturing cycle times. However, measurement technology that meets this need has not yet been established.

[0007] One of the potential non-contact electrical property measurement technologies is an inspection that utilizes second harmonic generation (SHG) due to the nonlinear optical properties of the object being measured. The nonlinear optical properties can be expressed, for example, as the product of the susceptibility and the electric field. The susceptibility is obtained from the intensity of the second harmonic. Furthermore, the band structure within the material can be obtained from each element of the susceptibility tensor.

[0008] Since most materials used as semiconductor substrates, such as silicon, have an inversion-symmetric crystal structure, second harmonics are not usually generated in the bulk state. However, Bloembergen et al. have theoretically investigated second harmonic generation due to the breaking of symmetry at the boundary surface of materials in Non-Patent Document 1. The second harmonic generation investigated in Non-Patent Document 1 has been quantitatively evaluated experimentally with the subsequent development of pulsed lasers.

[0009] In addition, Guidotti et al. experimentally evaluated the generation of second harmonics on a silicon surface having an inversion symmetric structure in Non-Patent Document 2. Patent Document 1 proposes a measurement method using second harmonics for the progress of a process in a semiconductor device. Patent Document 2 proposes a method for evaluating the presence of contaminants on a semiconductor substrate surface by observing second harmonics and sum frequencies generated under illumination with multiple wavelengths.

[0010] Patent Document 3 discloses a method for measuring the surface roughness at the interface between silicon and an oxide layer. It is described that by rotating a sample, the azimuth angle dependence of the intensity of the second harmonic can be measured and the distortion of the sample and the anisotropy of the crystal can be detected. In addition, as disclosed in Patent Document 4, the dynamic characteristics of the charge at the interface can be inferred by analyzing the time evolution of the intensity of the second harmonic. This is due to the fact that the intensity of the second harmonic depends on the interfacial electric field and that charge is generated near the interface by irradiation of the fundamental wave.

[0011] Furthermore, in Patent Document 5, which is an development of the technology in Patent Document 4, a method is proposed in which, in order to shorten the measurement time, ultraviolet light or the like is irradiated in addition to the fundamental wave to saturate the time evolution before measurement. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Japanese Patent Application Publication No. 04-340404 [Patent Document 2] U.S. Patent No. 6,788,405 [Patent Document 3] U.S. Pat. No. 5,557,409 [Patent Document 4] U.S. Patent No. 7,158,284 [Patent Document 5] US Patent Publication No. 2015 / 330908 [Patent Document 6] Patent Publication No. 2021-085698 [Non-patent literature]

[0013] [Non-Patent Document 1] BLOEMBERGEN, N. et. al., Light Waves at the Boundary of Nonlinear Media, Phys. Rev. 128, 606 (1962) [Non-Patent Document 2] Guidotti, D. et.al, Second harmonic generation in centro-symmetric semiconductors, Solid state communications 46.4 (1983): 337-340 Summary of the Invention [Problem to be solved by the invention]

[0014] As shown in these documents, in the measurement of second harmonics, observation of azimuth angle dependence and time evolution is cited as an effective analysis method. However, in order to obtain the azimuth angle dependence, it is necessary to rotate the sample, and the measurement takes a certain amount of time. Furthermore, since the intensity of the second harmonic evolves over time, the time evolution of the intensity of the second harmonic is superimposed on the azimuth angle dependence. By using the technology described in Patent Document 5, it is possible to saturate the time evolution in advance, but in that case it becomes difficult to observe the time evolution.

[0015] Despite the above problems, the related art does not disclose an effective means for separately acquiring the time evolution and the azimuth angle dependency. To solve this problem, a highly accurate method is required that can eliminate the influence of the time evolution by acquiring the azimuth angle dependency all at once and can measure the time evolution for each azimuth angle. A semiconductor measurement device that can improve the accuracy of such measurements is desired.

[0016] Other objects and novel features will become apparent from the description of this specification and the accompanying drawings.

[0017] The present disclosure has been made to solve such problems, and provides a semiconductor measuring device capable of improving measurement accuracy. [Means for solving the problem]

[0018] A semiconductor measurement device in one embodiment is a semiconductor measurement device that measures nonlinear light generated in a sample, and includes a laser light source that generates a fundamental wave having a first wavelength, an objective lens that focuses the fundamental wave on a sample surface, a wavelength filter that separates light reflected from the fundamental wave by the sample and signal light that is generated by irradiating the fundamental wave on the sample and has a second wavelength different from the first wavelength, and a detection unit that detects the signal light separated by the wavelength filter, wherein the detection unit is arranged to detect the signal light generated by the same fundamental wave in two or more different emission directions from the sample.

[0019] In the semiconductor measuring apparatus, the detection unit may include a detector that detects the intensity of the signal light on a pupil plane of the objective lens.

[0020] In the semiconductor measuring apparatus, the detector may be disposed at a conjugate position with respect to a pupil plane of the objective lens, and may have a plurality of light-sensitive surfaces.

[0021] In the semiconductor measuring device, the second wavelength may be half the first wavelength.

[0022] In the semiconductor measuring device, the laser light source may be a pulsed laser light source that generates the fundamental wave in a pulse form, and the pulse width of the fundamental wave may be 1 picosecond or less.

[0023] The semiconductor measuring device may further include a delay generator arranged on the optical path of the fundamental wave between the laser light source and the objective lens, and the delay generator may generate a time difference in the time it takes for one part of the fundamental wave to reach the sample relative to another part of the fundamental wave.

[0024] In the above-described semiconductor measuring device, the delay generator may include a transparent member having a distribution in thickness in an optical axis direction of the fundamental wave, and the time difference may be generated by a difference in optical path length of the fundamental wave transmitted through the transparent member.

[0025] In the above-described semiconductor measuring device, the delay generator may include a reflecting member having a distribution in height in the optical axis direction of the fundamental wave, and the time difference may be generated by a difference in optical path length of the fundamental wave reflected by the reflecting member.

[0026] In the above semiconductor measuring device, the detection unit may include a detector that detects the signal light generated by the fundamental wave having the time difference by dividing the signal light by the time difference.

[0027] In the above-mentioned semiconductor measuring device, the detection unit may include a detector having a plurality of light-sensitive surfaces, the number of the light-sensitive surfaces being the same as the number of the time differences generated by the delay generator, and each light-receiving surface may receive the signal light corresponding to the signal light of each time difference.

[0028] The semiconductor measurement device may further include a polarization controller arranged on the optical path of the fundamental wave between the laser light source and the objective lens, the polarization controller controlling the polarization state of the fundamental wave, and the detection unit may include a detector that detects the signal light and a polarization analyzer that analyzes the polarization state.

[0029] In the semiconductor measurement apparatus, the ellipsometer may generate interference fringes that reflect the polarization state of the signal light on the detector.

[0030] In the semiconductor measurement device, the polarization controller may generate a specific polarization state on a pupil plane of the objective lens.

[0031] In the above-mentioned semiconductor measurement device, the specific polarization state may include any one of radial polarization, azimuthal polarization, and a combination of radial polarization and azimuthal polarization.

[0032] The semiconductor measurement device may further include an annular light shaper arranged on the optical path of the fundamental wave between the laser light source and the objective lens, and the annular light shaper may shape the fundamental wave into an annular shape.

[0033] The semiconductor measuring device may further include a light splitting unit arranged on the optical path of the fundamental wave between the laser light source and the objective lens, and the light splitting unit may split the fundamental wave into two or more optical paths and adjust the optical path lengths of the split optical paths.

[0034] In the semiconductor measuring device, the light splitting unit may include a beam splitter that splits the fundamental wave into equal amplitude portions, and a mirror that reflects the fundamental wave.

[0035] In the above semiconductor measuring device, the detection unit may be a first detection unit, the wavelength filter may include a dichroic mirror, and the semiconductor measuring device may further include a second detection unit that detects the reflected light separated from the signal light by the dichroic mirror.

[0036] In the above semiconductor measuring device, the second detection unit may include a detector that detects intensity of the fundamental wave, and an ellipsometer that generates interference fringes on the detector that reflect the polarization state of the fundamental wave.

[0037] The semiconductor measurement device may further include a spatial phase modulator disposed on the optical path of the fundamental wave and between the laser light source and the objective lens.

[0038] In the semiconductor measuring apparatus, the optical axis of the objective lens may be perpendicular to the sample surface. Effect of the Invention

[0039] According to the present disclosure, it is possible to provide a semiconductor measuring device capable of improving measurement accuracy. [Brief description of the drawings]

[0040] [Figure 1] 1 is a configuration diagram illustrating a semiconductor measuring device according to an embodiment; [Diagram 2] 1A to 1C are diagrams showing two-dimensional images illustrating second harmonic components for each azimuth angle detected by a detector arranged at a conjugate position to the pupil plane of an objective lens in a semiconductor measuring device according to an embodiment overview. [Diagram 3] FIG. 1 is a flowchart illustrating a semiconductor measurement method using a semiconductor measurement device according to an embodiment. [Figure 4] 1 is a configuration diagram illustrating a semiconductor measuring device according to a first embodiment. [Diagram 5] 3 is a diagram illustrating a cross section perpendicular to the optical axis of a fundamental wave shaped by an annular optical shaper in the semiconductor measuring device according to the first embodiment. FIG. [Figure 6] 1 is a perspective view illustrating a delay generator having a distribution in thickness in the optical axis direction of a fundamental wave in the semiconductor measuring device according to the first embodiment. FIG. [Figure 7] 4 is a configuration diagram illustrating a semiconductor device according to another example of the first embodiment. FIG. [Figure 8] 13 is a diagram illustrating a time difference of a fundamental wave generated by a delay generator in a semiconductor measuring device according to another example of the first embodiment. FIG. [Figure 9] 1 is a configuration diagram illustrating a semiconductor measuring device according to a first embodiment. [Figure 10]4 is a flow chart illustrating a semiconductor measuring method using the semiconductor measuring device according to the first embodiment. [Figure 11] FIG. 1 is a configuration diagram showing a semiconductor measuring device according to a reference example. [Figure 12] FIG. 13 is a diagram showing the azimuth angle dependency detected by a detector in the semiconductor measuring device according to the reference example. [Figure 13] FIG. 13 is a diagram showing a configuration when the field of view is moved in the semiconductor measuring device according to the reference example. [Figure 14] 4 is a diagram illustrating an example of the configuration when the field of view is shifted in the semiconductor device according to the first embodiment. FIG. [Figure 15] FIG. 11 is a configuration diagram illustrating a semiconductor measuring device according to a second embodiment. [Figure 16] 11 is a perspective view illustrating a delay generator in the semiconductor measuring device according to the second embodiment. FIG. [Figure 17] FIG. 11 is a configuration diagram illustrating a semiconductor measuring device according to a third embodiment. [Figure 18] FIG. 13 is a configuration diagram illustrating a semiconductor measuring device according to a fourth embodiment. [Figure 19] FIG. 13 is a configuration diagram illustrating an example of a light splitting unit in a semiconductor measuring device according to a fourth embodiment. [Figure 20] 13 is a diagram illustrating an example of an intensity distribution at the position of the pupil plane of a fundamental wave split by a light splitting unit in the semiconductor measuring device according to the embodiment 4. FIG. [Figure 21] FIG. 13 is a configuration diagram illustrating a semiconductor measuring device according to a fifth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] For clarity of explanation, the following description and drawings are omitted and simplified as appropriate. In addition, in each drawing, the same elements are given the same reference numerals, and duplicate explanations are omitted as necessary. Some reference numerals and hatching are omitted so as not to make the drawings complicated.

[0042] (Overview of the embodiment) First, an overview of the embodiment will be described. The semiconductor measuring device of the present embodiment irradiates a sample such as a semiconductor device with laser light such as a pulse laser in order to measure contamination on the semiconductor surface and the amount of dopant and internal distortion inside the semiconductor, for example, in semiconductor device manufacturing. The semiconductor measuring device measures nonlinear light such as second harmonics generated in the sample near the semiconductor surface or boundary surface.

[0043] In a typical optical device, a method is used in which a sample having a laminated structure is irradiated with a fundamental wave with a controlled polarization direction, and the second harmonic at the interface of the laminated structure is detected. The intensity of the second harmonic depends on the angle (azimuth angle) between the crystal orientation and the fundamental wave. Therefore, information about the sample can be analyzed from this azimuth angle dependence.

[0044] The related technique of acquiring the azimuth angle dependence of the second harmonic by rotating the sample has a simple device configuration and inspection method. On the other hand, it takes a certain amount of time to rotate the sample. Furthermore, depending on the sample, the intensity of the second harmonic may evolve over time. Therefore, in the related technique, the intensity of the second harmonic may change during acquisition of the azimuth angle dependence.

[0045] Therefore, the semiconductor measurement device of this embodiment acquires the azimuth angle dependence of the second harmonic without rotating the sample. Specifically, the semiconductor measurement device measures the intensity distribution of the second harmonic collectively on the pupil plane of the objective lens.

[0046] Fig. 1 is a configuration diagram illustrating a semiconductor measuring device 1 according to an outline of an embodiment. From Fig. 1 onwards, a fundamental wave P1 is indicated by a dotted line, and a second harmonic wave P2 (signal light L2) is indicated by a solid line. As shown in Fig. 1, the semiconductor measuring device 1 of this embodiment includes an objective lens 26, a wavelength filter 27, and a detection unit 30. The semiconductor measuring device 1 may further include an optical member such as a beam splitter 25. In addition, the semiconductor measuring device 1 may further include a laser light source that generates laser light L1 including the fundamental wave P1.

[0047] The objective lens 26 focuses the laser light L1 including the fundamental wave P1 on the sample surface 41 of the sample 40. The fundamental wave P1 has a first wavelength. The fundamental wave P1 includes pulsed light. The laser light L1 including the fundamental wave P1 is simply referred to as the fundamental wave P1. The optical axis C of the objective lens 26 is disposed so as to be perpendicular to the sample surface 41 of the sample 40. As a result, the optical axis of the fundamental wave P1 is perpendicular to the sample surface 41. Note that perpendicular does not only mean strictly 90° but also means perpendicular within a range that includes unavoidable errors such as measurement errors.

[0048] Here, an XYZ Cartesian coordinate system is introduced for the convenience of explaining the semiconductor measuring device 1. The direction of the optical axis C of the objective lens 26 is defined as the Z-axis direction, and two directions perpendicular to the optical axis C of the objective lens 26 are defined as the X-axis direction and the Y-axis direction.

[0049] The wavelength filter 27 separates the reflected light R1, which is the fundamental wave P1 reflected by the sample 40, from the signal light L2, which is generated by irradiating the sample 40 with the fundamental wave P1. In other words, the wavelength filter 27 separates the signal light L2 from the reflected light R1. The signal light L2 has a second wavelength different from the first wavelength. The second wavelength is, for example, half of the first wavelength. Note that half does not mean strictly 1 / 2, but half within a range including unavoidable errors such as measurement errors. The signal light L2 includes pulsed light. The signal light L2 includes the second harmonic P2. The signal light L2 including the second harmonic P2 is simply called the second harmonic P2. The reflected light R1 includes the fundamental wave P1.

[0050] The detection unit 30 detects the second harmonic P2 separated from the fundamental wave P1 by the wavelength filter 27. The detection unit 30 is arranged to detect the second harmonic P2 generated by the same fundamental wave P1 in two or more different emission directions from the sample 40. Specifically, for example, the detection unit 30 may include a detector 31. In that case, the detector 31 is arranged at a conjugate position H2 of the pupil plane H1 of the objective lens 26. This allows the detector 31 to detect the second harmonic P2 generated by the same fundamental wave P1 in two or more different emission directions from the sample 40. The detector 31 detects the intensity of the second harmonic P2 at the pupil plane H1 of the objective lens 26.

[0051] The detection unit 30 may have an optical fiber in addition to or in combination with the detector 31. The detector 31 may be connected to one end of the optical fiber and detect the second harmonic P2 guided by the optical fiber. In this case, the other end of the optical fiber is disposed at a conjugate position H2 of the pupil plane H1 of the objective lens 26. Even with such a configuration, the detection unit 30 can detect the second harmonic P2 generated by the same fundamental wave P1 in two or more different emission directions from the sample 40.

[0052] 2 is a two-dimensional image illustrating components of the second harmonic P2 for each azimuth angle detected by the detector 31 arranged at the conjugate position H2 of the pupil plane H1 of the objective lens 26 in the semiconductor measuring device 1 according to the outline of the embodiment. In FIG. 2, the intensity distribution of the second harmonic P2 projected on the detector 31 is shown in gray scale. The fundamental wave P1 irradiating the sample 40 is shaped by a ring-shaped light shaper described later.

[0053] 2, the second harmonic P2 generated from the sample 40 exhibits a distribution that depends on the azimuth angle within the pupil plane H1 of the objective lens 26. The semiconductor measuring device 1 projects this azimuth angle distribution onto the detector 31, thereby making it possible to acquire information related to the azimuth angle dependency all at once.

[0054] Next, a semiconductor measurement method will be described. Fig. 3 is a flow chart illustrating a semiconductor measurement method using a semiconductor measurement device according to an embodiment. As shown in step S10 of Fig. 3, a fundamental wave P1 having a first wavelength is generated. For example, a laser light source 10 generates a fundamental wave P1 having a first wavelength.

[0055] Next, as shown in step S20, the fundamental wave P1 is focused on the sample surface 41. For example, the fundamental wave P1 is focused on the sample surface 41 by the objective lens 26. In step S20 in which the fundamental wave P1 is focused on the sample surface 41, the optical axis C of the objective lens 26 is perpendicular to the sample surface 41.

[0056] Next, as shown in step S30, the fundamental wave P1 reflected by the sample 40 and the second harmonic P2 generated from the sample 40 are separated by the wavelength filter 27. In step S30 of separating the fundamental wave P1 and the second harmonic P2, the second wavelength may be half the first wavelength.

[0057] Next, as shown in step S40, the detection unit 30 detects the second harmonic P2 separated by the wavelength filter 27. In step S40 of detecting the second harmonic P2, the detection unit 30 is arranged to detect the second harmonic P1 generated by the same fundamental wave P1 in two or more different emission directions from the sample 40.

[0058] Thus, according to the outline of this embodiment, the detection unit 30 is arranged to detect the second harmonic P2 generated by the same fundamental wave P1 in two or more different emission directions from the sample 40. Therefore, since the azimuth angle dependence of the second harmonic P2 is acquired all at once, the measurement accuracy can be improved without the influence of time development. In addition, since the azimuth angle dependence of the second harmonic P2 can be acquired without rotating the sample 40, the measurement throughput can be improved and the device configuration can be simplified. Furthermore, since the optical axis of the objective lens 26 is perpendicular to the sample surface 41, it is possible to perform measurement accompanied by a movement of the field of view by moving the sample 40. In addition, the time development can be measured in each direction at once.

[0059] (Embodiment 1) Next, a semiconductor measuring device according to the first embodiment will be described. The semiconductor measuring device according to the present embodiment includes an annular light shaper, a polarization controller, a delay generator, and the like, in comparison with the configuration of the semiconductor measuring device 1 described above. Fig. 4 is a configuration diagram illustrating the semiconductor measuring device 1a according to the first embodiment. As shown in Fig. 4, the semiconductor measuring device 1a includes a laser light source 10, an optical system 20, and a detection unit 30.

[0060] <Laser light source> The laser light source 10 generates a fundamental wave P1 having a first wavelength. For example, the laser light source 10 includes a pulsed laser light source that generates a pulsed fundamental wave P1. The pulse width of the fundamental wave P1 may be 1 picosecond or less. The fundamental wave P1 generated by the laser light source 10 is emitted from the laser light source 10 and guided to the optical system 20.

[0061] <Optical system> The optical system 20 generates nonlinear light by irradiating the fundamental wave P1 onto the sample 40. The nonlinear light includes, for example, the second harmonic P2. The nonlinear light including the second harmonic P2 is called signal light L2. As described above, the signal light L2 including the second harmonic P2 is simply called the second harmonic P2. The optical system 20 guides the generated second harmonic P2 to the detection unit 30. The optical system 20 also separates the reflected light R1, which is the fundamental wave P1 reflected by the sample 40, from the second harmonic P2 using a wavelength filter 27. Hereinafter, the optical members included in the optical system 20 will be described in detail.

[0062] The optical system 20 has a collimator 21, an annular light shaper 22, a polarization controller 23, a delay generator 24, a beam splitter 25, an objective lens 26, and a wavelength filter 27. The optical system 20 may further include optical members other than those described above, or some of the optical members described above may be omitted. For example, the delay generator 24 and the like may be omitted. The collimator 21, the annular light shaper 22, the polarization controller 23, the delay generator 24, and the beam splitter 25 are disposed on the optical path of the fundamental wave P1 between the laser light source 10 and the objective lens 26.

[0063] <Collimator> The collimator 21 converts the fundamental wave P1 output from the laser light source 10 into parallel light. The collimator 21 is, for example, a condenser lens. The fundamental wave P1 converted into parallel light enters the annular light shaper 22.

[0064] <Zonal light shaper> FIG. 5 is a diagram illustrating a cross section perpendicular to the optical axis of the fundamental wave P1 shaped by the annular light shaper 22 in the semiconductor measuring device 1a according to the first embodiment. In FIG. 5, the optical axis of the fundamental wave P1 is set in the X-axis direction. As shown in FIG. 5, the annular light shaper 22 shapes the fundamental wave P1 into an annular shape. The annular light shaper 22 may be an annular aperture having a light shielding portion 22a and a frame portion 22b, or may include a plurality of axicon lenses. The annular light shaper 22 adjusts the angle of incidence of the fundamental wave P1 incident on the sample 40 by shaping the fundamental wave P1 into an annular shape. Specifically, the angle of incidence is adjusted to be within a desired range by adjusting the inner and outer diameters of the annular fundamental wave P1 in the annular light shaper 22. For example, it is desirable to set the angle of incidence to about 45° to 60° at which the intensity of the second harmonic wave P2 is relatively high. Since the optimal angle of incidence differs depending on the sample 40, a mechanism capable of adjusting the angle of incidence is preferable. That is, the annular light shaper 22 may have a mechanism capable of adjusting the outer diameter of the light blocking portion 22a and the inner diameter of the frame portion 22b. The fundamental wave P1 shaped into an annular shape is incident on the polarization controller .

[0065] The polarization controller 23 includes, for example, a polarizer. The polarization controller 23 controls the polarization state of the fundamental wave P1. The polarization controller 23 may generate a specific polarization state on the pupil plane H1 of the objective lens 26. The polarization state includes linear polarization, circular polarization, radial polarization, and azimuthal polarization. The polarization state of the fundamental wave P1 may be linear polarization or circular polarization, but radial polarization or azimuthal polarization is preferable, as described below. The specific polarization state may be radial polarization, azimuthal polarization, or a combination of radial polarization and azimuthal polarization.

[0066] The delay generator 24 will be described later. The fundamental wave P1, the polarization state of which has been controlled, enters the beam splitter 25.

[0067] <Beam splitter> The beam splitter 25 reflects a part of the incident fundamental wave P1 and transmits a part of it. The beam splitter 25 may be a dichroic mirror that reflects the fundamental wave P1 and transmits the second harmonic wave P2. By using a dichroic mirror, the fundamental wave P1 and the second harmonic wave P2 can be used with high energy efficiency. The fundamental wave P1 reflected by the beam splitter 25 is incident on the objective lens 26.

[0068] <Objective lens> The objective lens 26 focuses the fundamental wave P1 on the sample surface 41 of the sample 40. The sample surface 41 is, for example, the upper surface of the sample 40. The fundamental wave P1 guided to the objective lens 26 by the beam splitter 25 is focused on the sample 40. Reflected light R1 of the fundamental wave P1 and a second harmonic P2 are emitted from the sample 40 irradiated with the fundamental wave P1.

[0069] The fundamental wave P1 reflected by the sample 40 and the second harmonic P2 emitted from the sample 40 pass through the objective lens 26 and enter the beam splitter 25. The beam splitter 25 transmits the fundamental wave P1 and the second harmonic P2. If the beam splitter 25 is a dichroic mirror, the beam splitter 25 transmits the second harmonic P2. The fundamental wave P1 and the second harmonic P2 that have passed through the beam splitter 25 enter the wavelength filter 27.

[0070] <Wavelength filter> The wavelength filter 27 separates the reflected light R1 resulting from the fundamental wave P1 being reflected by the sample 40 from the signal light L2 including the second harmonic P2 generated by irradiating the sample 40 with the fundamental wave P1. Specifically, the wavelength filter 27 removes the fundamental wave P1 and guides the second harmonic P2 to the detection unit 30. The wavelength filter 27 may be an optical element such as a short-pass filter, a band-pass filter, or a dichroic mirror, and may be an optical element capable of separating optical paths according to wavelength. The second harmonic P2 transmitted through the wavelength filter 27 enters the detection unit 30.

[0071] <Detection unit> The detection unit 30 may further include an ellipsometer 32 in addition to the detector 31. The ellipsometer 32 analyzes the polarization state. Specifically, the ellipsometer 32 extracts a desired polarization state of the second harmonic wave P2. For example, the ellipsometer 32 generates interference fringes reflecting the polarization state of the second harmonic wave P2 on the detector 31. The detector 31 may detect the interference fringes of the second harmonic wave P2.

[0072] The detector 31 may have multiple light-sensitive surfaces. The number of light-sensitive surfaces may be the same as the number of time differences generated by the delay generator 24 described later. Each light-receiving surface receives a second harmonic P2 corresponding to the second harmonic P2 of each time difference. The detector 31 in the detection unit 30 may detect the second harmonic P2 generated by the fundamental wave P1 with a time difference by dividing it into parts for each time difference.

[0073] The polarization analyzer 32 may be realized simply by a linear polarizer, or by applying an ellipsometric analysis method in which a Nomarski prism and a linear polarizer are arranged. This is an application of the ellipsometry method disclosed in Patent Document 6. The second harmonic P2 in the desired polarization state is detected by the detection unit 30. Here, the detection unit 30 is configured to be able to obtain the azimuth angle dependence of the intensity of the second harmonic P2 at a sufficiently high speed. Two specific examples are given below.

[0074] One example is as follows. That is, the detection unit 30 includes a detector 31 having multiple light-sensitive surfaces, such as a CMOS sensor or a split PMT. In this case, the detection unit 30 has an optical configuration in which the intensity distribution of the second harmonic P2 on the pupil plane H1 of the objective lens 26 is projected onto each of the light-sensitive surfaces. Such an optical configuration can be realized by locating the light-sensitive surface of the detector 31 at a conjugate position H2 of the pupil plane H1, or by placing an end face of an optical fiber at the conjugate position H2 of the pupil plane H1 and introducing it to the detector 31.

[0075] Another example is as follows. That is, a method of separating the second harmonic P2 in time without separating it in space. For example, the detection unit 30 may provide an optical path difference for each position on the pupil plane H1 and detect the second harmonic P2 with a detector 31 having high time resolution, such as a streak camera. This allows the detection unit 30 to detect the intensity distribution on the pupil plane H1 by dividing it by time.

[0076] Consider the polarization state of the fundamental wave P1 on the sample 40. When the fundamental wave P1 is controlled to be linearly polarized by a polarizer, the light at each azimuth angle has a different angle between the incident plane and the polarization direction. This angle will be referred to as the polarization angle hereinafter. The second harmonic P2 also exhibits dependency on the polarization angle. For this reason, in order to facilitate data analysis, it is desirable that the polarization angle at each azimuth is equal. Therefore, it is desirable that the polarization controller 23 converts the fundamental wave P1 into radial polarization or azimuth polarization. The fundamental wave P1, which includes radial polarization and azimuth polarization, has the same polarization angle in any azimuth plane. This makes it possible to facilitate analysis of the second harmonic P2.

[0077] <Delay Generator> The optical system 20 may further include a delay generator 24. For example, the fundamental wave P1 output from the polarization controller 23 is incident on the delay generator 24. The fundamental wave P1 output from the delay generator 24 is incident on the beam splitter 25. FIG. 6 is a perspective view illustrating the delay generator 24 having a distribution in thickness in the optical axis direction in the semiconductor measuring device 1a according to the first embodiment. As shown in FIG. 6, the delay generator 24 includes a transparent member having a distribution in thickness in the optical axis direction of the fundamental wave P1. Having a distribution in thickness means that the delay generator 24 has two or more thicknesses that are different from each other depending on the part of the delay generator 24. The thickness of the delay generator 24 may change continuously or may change stepwise. By transmitting the fundamental wave P1 through a transparent member having a distribution in thickness, the timing of irradiating the sample 40 can be shifted. In this way, the delay generator 24 generates a time difference due to the difference in the optical path length of the fundamental wave P1 transmitted through the transparent member. In the figure, the delay generator 24 is divided into four parts with different optical path differences, but the number of divisions may be determined arbitrarily. In this case, the detector 31 may have four light-sensitive surfaces corresponding to the four parts of the delay generator 24.

[0078] Fig. 7 is a configuration diagram illustrating a semiconductor measuring apparatus 1b according to another example of embodiment 1. As shown in Fig. 7, in the optical system 20 of the semiconductor measuring apparatus 1b, the delay generator 24 may be disposed between the beam splitter 25 and the objective lens 26 instead of being disposed between the annular light shaper 22 and the beam splitter 25.

[0079] 8 is a diagram illustrating a time difference of the fundamental wave P1 generated by the delay generator 24 in the semiconductor measuring device 1b according to another example of the first embodiment. As shown in FIG. 8, the delay generator 24 includes a portion 241 and a portion 242 having different thicknesses in the optical axis direction, and the portion 241 has a smaller thickness in the optical axis direction than the portion 242. Therefore, the fundamental wave P1 transmitted through the portion 241 generates a time difference T1 in the timing of irradiating the sample 40 compared to the fundamental wave P1 transmitted through the portion 242. In this way, the timing of irradiating the sample 40 can be shifted by transmitting the fundamental wave P1 through a transparent member having a thickness distribution in the optical axis direction.

[0080] There are two problems that the delay generator 24 can solve. The first problem is the generation of a non-coaxial second harmonic P2. When the annular fundamental wave P1 is focused on the sample surface 41, the optical fields on the sample surface 41 may interfere with each other and be concentrated in one direction. In that case, even if the second harmonic P2 is detected for each azimuth angle, the intensity becomes constant, so that the desired distribution cannot be obtained. The second problem is the signal intensity. In general, the intensity of the second harmonic P2 is much smaller than that of the fundamental wave P1. For this reason, dispersing light on the pupil surface 26a is not preferable from the viewpoint of S / N. On the other hand, from the viewpoint of the damage threshold of the sample 40, there is a limit to the intensity of the fundamental wave P1 that can be irradiated with one pulse.

[0081] In order to solve the above problems, the fundamental wave P1 passes through the delay generator 24 before irradiating the sample 40. This makes it possible to generate a time difference for each azimuth angle with respect to the timing at which the fundamental wave P1 irradiates the sample 40. The delay generator 24 may be made of a material that has a thickness distribution in the azimuth angle direction as shown in FIG. 6, for example, and is transparent to the wavelength of the fundamental wave P1. This makes it necessary that the intensity at each azimuth angle component, rather than the total intensity of all the fundamental waves P1, does not exceed the damage threshold, and thus the restriction on the intensity of the fundamental wave P1 is relaxed.

[0082] The irradiation timing to be shifted for each azimuth angle is about the pulse width to the repetition period of the pulse laser (1 picosecond to 100 nanoseconds), which is sufficiently short with respect to the exposure time of the detector 31 (> milliseconds) and the time evolution of the intensity of the second harmonic P2 (> several seconds). Therefore, this shift does not impair the batch acquisition. Also, if only the first objective needs to be achieved, it is sufficient to suppress interference on the sample 40 as long as the S / N is sufficient. Therefore, the shift in the irradiation timing may be about the pulse width. As a result, the delay generator 14 generates a time difference in which a part of the fundamental wave P1 reaches the sample 40 relative to the other part. The detector 31 may be arranged to detect the second harmonic P2 generated by the same fundamental wave P1 by separating them at different times in two or more different emission directions from the sample 40.

[0083] Furthermore, the detector 31 may have a light-sensitive surface corresponding to the division of the delay generator 24. In this case, one detector 31 does not necessarily have to have a plurality of light-sensitive surfaces, and a plurality of detectors 31 may be arranged. The detector 31 may be any photodetector such as a photodiode or a photomultiplier tube. Furthermore, the fundamental wave P1 may be focused for each division of the delay generator 24 by arranging a lens array in front of the detector 31. This also increases the amount of detection signals. Here, the number of divisions is arbitrarily set based on the desired azimuth-dependence period and S / N ratio. In addition, the light-shielding portion 22a and the frame portion 22b of the annular light shaper 22 may be designed according to this number of divisions. Specifically, a structure in which holes are arranged in an annular shape in the number of divisions may be used.

[0084] <Control system> FIG. 9 is a configuration diagram illustrating a semiconductor measuring device 1a according to the first embodiment. As shown in FIG. 9, the semiconductor measuring device 1a may be placed on an optical table 52 supported by a stand 50. An isolator 51 may be placed between the stand 50 and the optical table 52. The isolator 51 removes vibrations from the floor surface on which the stand 50 is placed. Any of the laser light source 10, the optical system 20, and the detection unit 30 may be fixed to a frame 53 provided on the optical table 52. The sample 40 is held by a holder 54 and placed on a stage 55. The stage 55 may be movable in the X-axis direction, the Y-axis direction, and the Z-axis direction, or may be rotatable about at least one of the X-axis direction, the Y-axis direction, and the Z-axis direction as a rotation axis.

[0085] The semiconductor measuring apparatus 1a may further include a control device 60, a stage controller 61, a signal processing unit 62, and a laser light source control unit 63. The control device 60 controls the operations of the stage controller 61, the signal processing unit 62, and the laser light source control unit 63. The control device 60 includes an information processing device such as a PC (Personal Computer) or a server.

[0086] The stage controller 61 controls the position of the stage 55. For example, the stage controller 61 changes the position of the stage 55 by moving or rotating the stage 55. In this way, the stage controller 61 controls the position of the sample 40 irradiated with the fundamental wave P1.

[0087] The signal processing unit 62 converts the intensity and distribution of the second harmonic P2 detected by the detection unit 30 into a signal. Then, the signal processing unit 62 may process the converted signal or may send the converted signal to the control device 60.

[0088] The laser light source control unit 63 controls the generation of the fundamental wave P1 by the laser light source 10. The laser light source control unit 63 controls at least one of the intensity, wavelength, and pulse width of the generated fundamental wave P1.

[0089] <Semiconductor measurement method> Next, a semiconductor measurement method will be described. Fig. 10 is a flow chart illustrating a semiconductor measurement method using the semiconductor measurement device according to the first embodiment. As shown in Fig. 10, compared to the semiconductor measurement method in the outline of the above-mentioned embodiment, the semiconductor measurement method of this embodiment may further include at least one of step S11 of shaping the fundamental wave P1 into an annular shape by the annular light shaper 22, step S12 of controlling the polarization state of the fundamental wave P1 by the polarization controller 23, and step S13 of generating a time difference by the delay generator 24 for a part of the fundamental wave P1 to reach the sample 40 relative to the other part.

[0090] 10, in step S10 of generating a fundamental wave P1, the control device 60 may control the laser light source control unit 63 to cause the laser light source 10 to generate a fundamental wave P1 having a first wavelength. In step S10, the laser light source 10 may include a pulsed laser light source that generates a pulsed fundamental wave P1, and the pulse width of the fundamental wave P1 may be 1 picosecond or less.

[0091] Next, as shown in step S11, the fundamental wave P1 is shaped into an annular shape by the annular light shaper 22.

[0092] Next, as shown in step S12, the polarization state of the fundamental wave P1 is controlled by the polarization controller 23. In step S12, the polarization controller 23 may generate a specific polarization state on the pupil plane H1 of the objective lens 26. The specific polarization distribution may include any of radial polarization, azimuthal polarization, and a combination of radial polarization and azimuthal polarization. In this case, in step S40 of detecting the second harmonic wave P2, the ellipsometer 32 may generate interference fringes reflecting the polarization state of the second harmonic wave P2 on the detector 31.

[0093] Next, as shown in step S13, the delay generator 24 generates a time difference between when a part of the fundamental wave P1 reaches the sample 40 relative to the other part. In step S13, the delay generator 24 may include a transparent member having a distribution in thickness in the optical axis direction of the fundamental wave P1, and may generate a time difference by a difference in the optical path length of the fundamental wave P1 transmitted through the transparent member. In this case, the detection unit 30 may include a detector 31 that detects the second harmonic P2 generated by the fundamental wave P2 having a time difference by dividing it by time difference. For example, the detection unit 30 may include a detector 31 having a plurality of photosensitive surfaces. The number of photosensitive surfaces is the same as the number of time differences generated by the delay generator 24, and each photoreceptive surface receives the second harmonic P2 so as to correspond to the second harmonic P2 of each time difference.

[0094] Next, as shown in step S20, for example, the control device 60 controls the stage controller 61 to cause the objective lens 26 to focus the fundamental wave P1 on the sample surface 41.

[0095] Next, as shown in step S30, for example, the control device 60 controls the optical system 20a to cause the wavelength filter 27 to separate the fundamental wave P1 and the second harmonic wave P2.

[0096] Next, in step S40 of detecting the second harmonic P2, the detection unit 30 may include a detector 31 that detects the intensity of the second harmonic P2 at a pupil plane H1 of the objective lens 26. The detector 31 is disposed at a conjugate position H2 of the pupil plane H1 of the objective lens 26, and may have a plurality of light-sensitive surfaces.

[0097] Next, before describing the effects of this embodiment, a reference example and problems in the reference example will be described. After that, the effects of this embodiment will be described in comparison with the reference example. Note that the semiconductor measuring device according to the reference example is also included in the technical concept of this embodiment.

[0098] FIG. 11 is a configuration diagram showing a semiconductor measuring device 101 according to a reference example. FIG. 12 is a diagram showing the azimuth angle dependency detected by the detector 31 in the semiconductor measuring device 101 according to the reference example. As shown in FIG. 11 and FIG. 12, the semiconductor measuring device 101 according to the reference example focuses the fundamental wave P1 on the sample 40 at an incident angle α tilted with respect to the sample surface 41 of the sample 40. Then, the semiconductor measuring device 101 detects the second harmonic P2 generated from the sample 40 at a reflection angle α tilted with respect to the sample surface 41. The semiconductor measuring device 101 rotates around a rotation axis W perpendicular to the sample surface 41 and repeats the detection of the second harmonic P2. In this way, the azimuth angle dependency as shown in FIG. 12 is obtained. The azimuth angle dependency is obtained by plotting the intensity of the second harmonic P2 at each azimuth angle in the radial direction.

[0099] In order to obtain the azimuth angle dependency, the semiconductor measuring device 101 of the reference example needs to rotate the sample 40 around the rotation axis W, and the measurement takes a certain amount of time. Furthermore, the intensity of the second harmonic P2 evolves over time. Therefore, the time evolution of the intensity of the second harmonic P2 is superimposed on the azimuth angle dependency.

[0100] Fig. 13 is a diagram showing the configuration when the field of view is moved in the semiconductor measuring device 101 according to the reference example. As shown in Fig. 13, generally, when the XY stage is moved to move the field of view, the rotation axis W moves together. In other words, the optical axis and the rotation axis W are always misaligned. To adjust this, a mechanism is required to move the rotation axis W independently of the field of view movement, for example, by attaching the XY stage closer to the sample 40 than the rotation stage, which places a large restriction on the device configuration.

[0101] Next, the effects of this embodiment will be described. FIG. 14 is a diagram illustrating the configuration of the semiconductor measuring device 1a according to the first embodiment when the field of view is moved. The semiconductor measuring device 1a of this embodiment can acquire the azimuth angle dependence all at once without rotating the sample 40. In addition, since a rotating mechanism for the sample 40 is not required, the configuration of the device can be simplified, the cost of the device can be reduced, and the ease of alignment and field of view movement can be realized. In addition, when the field of view is moved, since there is no rotation axis W, adjustment with the optical axis is not necessarily required. Therefore, the throughput of the measurement can be significantly improved.

[0102] Furthermore, the semiconductor measuring device 1a of this embodiment can obtain the azimuth angle dependency of the second harmonic P2 separately from the time evolution, thereby improving the accuracy of the azimuth angle dependency of the second harmonic P2.

[0103] The semiconductor measuring device 1a of this embodiment can measure the time evolution of the intensity of the second harmonic P2 in all desired directions by continuously irradiating the fundamental wave P1. For example, in a plane perpendicular to the optical axis of the second harmonic P2, the intensity of the second harmonic P2-1 at a position of φ=0° from a predetermined radial direction and the intensity of the second harmonic P2-2 at a position of φ=45° from a predetermined radial direction evolve over time. Usually, when measuring the time evolution of the intensity of the second harmonic P2, the position is limited to one direction. Therefore, if the angle is not one at which a desired signal can be obtained, there is a possibility that information will be missed. The semiconductor measuring device 1 of this embodiment can measure the time evolution of the second harmonic P2 from φ=0° to 360°, so there is little loss of information and it is advantageous in terms of acquiring the time evolution.

[0104] Although it also differs depending on the sample 40, the time evolution acquires changes over about several hundred seconds. Therefore, when detecting in multiple directions, the sample 40 is repeatedly measured at additional points. This requires several thousand seconds or more. However, the semiconductor measuring device 1 of this embodiment can acquire the time evolution in all directions at once, so it can be compressed to about several hundred seconds, the same as acquisition in one direction.

[0105] In addition, the semiconductor measuring device 1 of this embodiment can eliminate the need for adjustment of the rotation axis and optical axis of the sample 40 as described above. This has the advantages of not requiring an adjustment mechanism, improving the accuracy of the azimuth angle dependency, and making it very easy to move the field of view of the sample 40 by moving the stage. Considering that the rotation stage is generally installed closer to the sample 40 than the XY stage, it is considered that the rotation axis and optical axis may be misaligned due to the stage movement. Therefore, it is necessary to introduce eucentric control or to attach the XY stage closer to the sample 40 than the rotation stage. This is a major constraint on the device configuration. The semiconductor measuring device 1 of this embodiment releases such constraints and allows the field of view of the sample 40 to be moved freely.

[0106] (Embodiment 2) Next, a semiconductor measuring apparatus according to a second embodiment will be described. The semiconductor measuring apparatus according to this embodiment is different from the semiconductor measuring apparatus 1a according to the first embodiment in the configuration and position of the delay generator. FIG. 15 is a configuration diagram illustrating the semiconductor measuring apparatus according to the second embodiment. FIG. 16 is a perspective view illustrating the delay generator in the semiconductor measuring apparatus according to the second embodiment. As shown in FIGS. 15 and 16, in the semiconductor measuring apparatus 2 according to this embodiment, the optical system 20a has a delay generator 24a instead of the delay generator 24.

[0107] Unlike the delay generator 24 of the first embodiment, the delay generator 24a reflects the fundamental wave P1 without transmitting it, thereby causing a shift in the irradiation timing of the sample 40. For example, the delay generator 24a has a reflecting member divided into a plurality of portions B1 to B4, the reflecting surfaces of which have different positions D1 to D4 in the optical axis direction of the fundamental wave P1. The delay generator 24a is disposed on the +X-axis direction side of the beam splitter 25 in the optical system 20a. Therefore, the beam splitter 25 is disposed between the polarization controller 23 and the delay generator 24a.

[0108] The fundamental wave P1 emitted from the polarization controller 23 enters the beam splitter 25. The beam splitter 25 transmits a portion of the fundamental wave P1 incident from the -X-axis direction. The fundamental wave P1 transmitted through the beam splitter 25 is reflected by the delay generator 24a. The fundamental wave P1 reflected by the delay generator 24a enters the beam splitter 25 from the +X-axis direction. The beam splitter 25 reflects a portion of the fundamental wave P1 incident from the +X-axis direction and causes it to enter the objective lens 26. The fundamental wave P1 incident on the beam splitter 25 from the -X-axis direction and reflected by the beam splitter 25 is separated by the wavelength filter 27. The other optical paths are the same as those in the first embodiment.

[0109] In this way, the delay generator 24a includes a reflecting member having a distribution in height in the optical axis direction of the fundamental wave P1, and generates a time difference due to the difference in the optical path length of the fundamental wave P1 reflected by the reflecting member. Note that the delay generator 24a may be any means, such as a deformable mirror, that allows a part of the light reflected by the delay generator to have a different optical path length from the other parts. As a semiconductor measurement method, in step S13 for generating a time difference in the time it takes for a part of the fundamental wave P1 to reach the sample 40 compared to the other parts, the delay generator 24a generates a time difference due to the difference in the optical path length of the fundamental wave P1 reflected by the reflecting member.

[0110] The delay generator 24a requires a reflective member having a high reflectance with respect to the fundamental wave P1. Unlike the delay generator 24, the delay generator 24a does not pass through a refractive index medium of different thickness, and therefore reduces device error factors such as changes in pulse width due to the split wavefront. Other configurations and effects of the second embodiment are included in the description of the first embodiment.

[0111] (Embodiment 3) Next, a semiconductor measuring device according to the third embodiment will be described. The semiconductor measuring device according to the third embodiment is different from the semiconductor measuring device 1a according to the first embodiment in that a dichroic mirror is used for the wavelength filter 27. FIG. 17 is a configuration diagram illustrating a semiconductor measuring device according to the third embodiment. As shown in FIG. 17, in the semiconductor measuring device 3 according to the present embodiment, the optical system 20b uses a dichroic mirror for the wavelength filter 27b. The detection unit 30b further includes a detector 33 and a polarimeter 34 in addition to the detector 31 and the polarimeter 32. The detector 31 and the polarimeter 32 detect and analyze the second harmonic wave P1, respectively, as in the first and second embodiments. The detector 33 and the polarimeter 34 detect and analyze the fundamental wave P1 separated from the second harmonic wave P2 by the dichroic mirror. Specifically, the detector 33 detects the intensity of the fundamental wave P1. The polarimeter 34 generates an interference fringe reflecting the polarization state of the fundamental wave P1 on the detector 33.

[0112] The fundamental wave P1 and the second harmonic wave P2 transmitted through the beam splitter 25 are separated by the wavelength filter 27b. The wavelength filter 27b including a dichroic mirror, for example, reflects the fundamental wave P1 and transmits the second harmonic wave P2. Note that, if the detector 31 and the ellipsometer 32 are arranged to detect and analyze the second harmonic wave P1, and the detector 33 and the ellipsometer 34 are arranged to detect and analyze the fundamental wave P1, the wavelength filter 27b may reflect the second harmonic wave P2 and transmit the fundamental wave P1. The other optical paths are the same as those in the first embodiment.

[0113] In the semiconductor measurement method, in step S30 of separating the fundamental wave P1 and the second harmonic wave P2, the wavelength filter 27b includes a dichroic mirror. Then, in step S40 of detecting the second harmonic wave P2, the fundamental wave P1 separated from the second harmonic wave P2 by the dichroic mirror is detected.

[0114] According to this embodiment, since a dichroic mirror is used for the wavelength filter 27b, the fundamental wave P1 separated from the second harmonic wave P2 can also be detected by a separate detector 33. The detection result can be used to calibrate the intensity distribution of the second harmonic wave P2. In addition, the reflected light R1 from the sample 40 can be used for ellipsometric analysis or the like by the polarization analyzer 34 that detects the fundamental wave P1. Other configurations and effects of the third embodiment are included in the description of the first and second embodiments.

[0115] (Embodiment 4) Next, a semiconductor measuring device according to a fourth embodiment will be described. The semiconductor measuring device according to this embodiment uses a light splitting unit that performs amplitude division instead of the annular light shaper 22 and the delay generator 24, as compared with the semiconductor measuring device 1 according to the first embodiment. FIG. 18 is a configuration diagram illustrating a semiconductor measuring device 4 according to the fourth embodiment. As shown in FIG. 18, in the semiconductor measuring device 4 according to this embodiment, the optical system 20c has a light splitting unit 28 instead of the annular light shaper 22 and the delay generator 24. The light splitting unit 28 is disposed on the optical path of the fundamental wave P1 between the laser light source 10 and the objective lens 26. The light splitting unit 28 splits the fundamental wave P1 into two or more optical paths and adjusts the optical path lengths of the divided optical paths. A specific example will be described below.

[0116] Fig. 19 is a configuration diagram illustrating the light splitting unit 28 in the semiconductor measuring device 4 according to the fourth embodiment. As shown in Fig. 19, the light splitting unit 28 includes a beam splitter 71 and a mirror 72. In the figure, the light splitting unit 28 includes one beam splitter 71 and one mirror 72. However, the light splitting unit 28 may include a plurality of beam splitters 71 and a plurality of mirrors 72. The beam splitter 71 splits the fundamental wave P1 into equal amplitude parts. The mirror 72 reflects the fundamental wave P1.

[0117] The parallel light including the fundamental wave P1 emitted from the collimator 21 is split by the beam splitter 71. The beam splitter 71 transmits one of the split light beams and reflects the other. The fundamental wave P1-1 reflected by the beam splitter 71 is reflected again by the mirror 72. As a result, the fundamental wave P1-1 reflected by the mirror 72 and the fundamental wave P1-2 transmitted through the beam splitter 71 are made parallel.

[0118] Here, the optical path difference (OPD, Optical Pass Delay) between the fundamental wave P1-1 and the reflected light of the fundamental wave P1-2 can be controlled by the distance D between the beam splitter 71 and the mirror 72 and the thickness of the beam splitter 71. In this way, the split fundamental wave P1 replicates the parallel light. Therefore, it is possible to suppress the unevenness of the azimuth distribution of the light intensity. Furthermore, by providing multiple stages of the light splitting units 28, the number of splits can be doubled at a time. The final number of splits is determined by the desired period of azimuth angle dependency and S / N ratio.

[0119] 20 is a diagram illustrating an example of an intensity distribution at the position of the pupil plane 26a of the fundamental wave P1 split by the light splitting unit 28 in the semiconductor measuring device 4 according to the fourth embodiment. As shown in FIG. 20, the light splitting unit 28 splits the fundamental wave P1 emitted from the collimator 21 into a plurality of beam lights. However, in order to unify the angle of incidence on the sample 40, it is preferable that the split beam lights are arranged in an annular shape regardless of the number of splits. The semiconductor measuring method may further include a step of splitting the fundamental wave P1 into two or more optical paths by the light splitting unit 28 and adjusting the optical path lengths of the split optical paths.

[0120] According to this embodiment, the semiconductor measuring device 4 can adjust the optical path lengths of the split optical paths by the light splitting unit 28, and therefore can generate a time difference by the difference in the optical path length of the fundamental wave P1 without the delay generator 24. Also, the semiconductor measuring device 4 can shape the fundamental wave P1 into an annular shape without the annular light shaper 22. Other configurations and effects of the fourth embodiment are included in the descriptions of the first to third embodiments.

[0121] (Embodiment 5) Next, a semiconductor measuring apparatus according to a fifth embodiment will be described. The semiconductor measuring apparatus according to this embodiment is an example that does not use a delay generator 24, as compared with the semiconductor measuring apparatus 1 according to the first embodiment described above. FIG. 21 is a configuration diagram illustrating a semiconductor measuring apparatus 5 according to the fifth embodiment. As shown in FIG. 21, in the semiconductor measuring apparatus 5 according to this embodiment, the optical system 20d does not have a delay generator 24. When the delay generator 24 is not used, the fundamental wave P1 focused by the objective lens 26 may interfere on the sample surface 41.

[0122] In general, as in the above-mentioned reference example, when the fundamental wave P1 is incident from one direction, the optical electric field of the sample surface 41 has a component in a direction parallel to the sample surface 41. The optical electric field of the sample surface 41 cannot be made to be only in a direction perpendicular to the sample surface 41.

[0123] On the other hand, in the case where the semiconductor measuring device 5 of this embodiment does not have the delay generator 24, when radially polarized light is incident on the sample surface 41 from all azimuth angles, the optical electric field on the sample surface 41 is concentrated only in the direction perpendicular to the sample surface 41 due to interference. Therefore, in order to prevent the generation of an optical electric field perpendicular to the sample surface 41, azimuthally polarized light is made to be incident on the sample surface 41 from all azimuth angles. Generally, the second-order nonlinear optical constant takes the form of a tensor. Therefore, when there are multiple electric field directions on the sample surface 41, complex behavior is exhibited. Therefore, by concentrating the electric field direction in one direction, the number of tensor terms involved can be reduced, and the analysis of the second harmonic P2 can be facilitated.

[0124] As described above, the polarization direction of the fundamental wave P1 on the sample surface 41 is a very important factor in detecting the second harmonic wave P2. The polarization direction can be controlled using not only the polarization controller 23 such as a polarizer, but also the spatial phase modulator 29. The spatial phase modulator 29 is disposed on the optical path of the fundamental wave P1 between the laser light source 10 and the objective lens 26. Specifically, the fundamental wave P1 emitted from the annular light shaper 22 is reflected by the mirror 73 and then converted into polarized light by the polarization controller 23. The fundamental wave P1 converted into polarized light by the polarization controller 23 enters the spatial phase modulator 29. The spatial phase modulator 29 adjusts the spatial distribution of the fundamental wave P1, such as the polarization state of the fundamental wave P1. The fundamental wave P1 emitted from the spatial phase modulator 29 enters the beam splitter 25. The semiconductor measurement method further includes a step of controlling the polarization state of the fundamental wave P1 by the spatial phase modulator 29.

[0125] According to this embodiment, the semiconductor measuring device 5 can perform polarization control with even higher degree of freedom by using the spatial phase modulator 29. Other configurations and effects of the fifth embodiment are included in the descriptions of the first to fourth embodiments.

[0126] The present disclosure is not limited to the above-mentioned embodiments, and can be appropriately modified without departing from the spirit of the present disclosure. For example, the configurations of the first to fifth embodiments can be combined with each other. In addition, the following semiconductor measurement method is also within the scope of the technical idea of ​​the embodiments.

[0127] (Appendix 1) A semiconductor measurement method using a semiconductor measurement device that measures nonlinear light generated in a sample, comprising: a laser light source that generates a fundamental wave having a first wavelength; an objective lens that focuses the fundamental wave on a sample surface; a wavelength filter for separating a reflected light of the fundamental wave reflected by the sample from a signal light generated by irradiating the fundamental wave on the sample, the signal light having a second wavelength different from the first wavelength; a detection unit for detecting the signal light separated by the wavelength filter; Equipped with The detection unit is arranged to detect the signal light generated by the same fundamental wave in two or more different emission directions from the sample, generating the fundamental wave by the laser light source; focusing the fundamental wave on a sample surface by the objective lens; separating the reflected light from the signal light by the wavelength filter; detecting the signal light by the detection unit; A semiconductor measurement method comprising: (Appendix 2) In the step of detecting the signal light, the detection unit includes a detector that detects an intensity of the signal light at a pupil plane of the objective lens; 2. The semiconductor metrology method of claim 1. (Appendix 3) In the step of detecting the signal light, The detector comprises: Located at a conjugate position of the pupil plane of the objective lens, having a plurality of light-sensitive surfaces; 3. The semiconductor metrology method of claim 2. (Appendix 4) In the step of separating the reflected light from the signal light, The second wavelength is half the first wavelength. 2. The semiconductor metrology method of claim 1. (Appendix 5) In the step of generating a fundamental wave, the laser light source includes a pulsed laser light source that generates the fundamental wave in a pulse form, The pulse width of the fundamental wave is 1 picosecond or less. 2. The semiconductor metrology method of claim 1. (Appendix 6) the semiconductor measurement device further includes a delay generator disposed on an optical path of the fundamental wave between the laser light source and the objective lens, The method further comprises the step of generating a time difference by the delay generator at which a part of the fundamental wave reaches the sample relative to another part of the fundamental wave. 2. The semiconductor metrology method of claim 1. (Appendix 7) In the step of generating a time difference in which a part of the fundamental wave reaches the sample relative to another part of the fundamental wave, The delay generator comprises: a transparent member having a thickness distribution in the optical axis direction of the fundamental wave, The time difference is generated by a difference in optical path length of the fundamental wave transmitted through the transmitting member. 7. The semiconductor measurement method according to claim 6. (Appendix 8) In the step of generating a time difference in which a part of the fundamental wave reaches the sample relative to another part of the fundamental wave, The delay generator comprises: a reflecting member having a distribution in height in the optical axis direction of the fundamental wave, generating the time difference by a difference in optical path length of the fundamental wave reflected by the reflecting member; 7. The semiconductor measurement method according to claim 6. (Appendix 9) In the step of detecting the signal light, the detection unit includes a detector that detects the signal light generated by the fundamental wave having the time difference by dividing the signal light by the time difference, 7. The semiconductor measurement method according to claim 6. (Appendix 10) In the step of detecting the signal light, the detection unit includes a detector having a plurality of light-sensitive surfaces; the number of said photosensitive surfaces is equal to the number of said time differences generated by said delay generator; each light receiving surface receives the signal light corresponding to the signal light of each time difference; 7. The semiconductor measurement method according to claim 6. (Appendix 11) the semiconductor measurement device further includes a polarization controller disposed on an optical path of the fundamental wave between the laser light source and the objective lens, The polarization controller further includes controlling the polarization state of the fundamental wave. In the step of detecting the signal light, The detection unit includes: a detector for detecting the signal light; an ellipsometer for analyzing the polarization state; having 2. The semiconductor metrology method of claim 1. (Appendix 12) In the step of detecting the signal light, the ellipsometer generates interference fringes on the detector that reflect the polarization state of the signal light; 12. The semiconductor metrology method of claim 11. (Appendix 13) In the step of controlling the polarization state of the fundamental wave, The polarization controller generates a specific polarization state on a pupil plane of the objective lens. 12. The semiconductor metrology method of claim 11. (Appendix 14) In the step of controlling the polarization state of the fundamental wave, The specific polarization distribution includes any of radial polarization, azimuthal polarization, and a combination of radial polarization and azimuthal polarization. 14. The semiconductor metrology method of claim 13. (Appendix 15) the semiconductor measuring device further includes a light splitting unit disposed on an optical path of the fundamental wave between the laser light source and the objective lens, The optical splitting unit further comprises a step of splitting the fundamental wave into two or more optical paths and adjusting the optical path lengths of the split optical paths. 2. The semiconductor metrology method of claim 1. (Appendix 16) In the step of adjusting the optical path length of the divided optical path, The optical splitting unit includes: a beam splitter that splits the fundamental wave into equal amplitude parts; A mirror that reflects the fundamental wave; Including, 16. The semiconductor metrology method of claim 15. (Appendix 17) In the step of separating the reflected light from the signal light, the wavelength filter includes a dichroic mirror; In the step of detecting the signal light, the detection unit is a first detection unit, Further comprising a second detection unit that detects the reflected light separated from the signal light by the dichroic mirror. 2. The semiconductor metrology method of claim 1. (Appendix 18) In the step of detecting the signal light, The second detection unit is A detector for detecting the intensity of the fundamental wave; an ellipsometer that generates interference fringes on the detector that reflect the polarization state of the fundamental wave; having 18. The semiconductor metrology method of claim 17. (Appendix 19) the semiconductor measurement device further includes a spatial phase modulator disposed on an optical path of the fundamental wave between the laser light source and the objective lens, Further comprising controlling the polarization state of the fundamental wave by the spatial phase modulator. 2. The semiconductor metrology method of claim 1. (Appendix 20) In the step of focusing the fundamental wave on a sample surface, The optical axis of the objective lens is perpendicular to the sample surface. 2. The semiconductor metrology method of claim 1. [Explanation of symbols]

[0128] 1, 1a, 1b, 2, 3, 4, 5, 101 Semiconductor measuring device 10 Laser light source 20, 20a, 20b, 20c, 20d optics 21 Collimator 22 Annular Light Shaper 22a Light shielding part 22b Frame 23 Polarization Controller 24, 24a Delay Generator 25 Beam splitter 26 Objective Lens 27, 27b Wavelength filters 28 Optical splitter unit 29 Spatial Phase Modulator 30, 30b Detection unit 31, 33 Detector 32, 34 Ellipsometer 40 Samples 41 Sample surface 50 Mount 51 Isolator 52 Optical surface plate 53 Frames 54 Holder 55 Stages 60 Control device 61 Stage Controller 62 Signal Processing Section 63 Laser light source control unit 71 Beam splitter 72, 73 Mirror 241, 242 parts B1, B2, B3, B4 part C optical axis D1, D2, D3, D4 position H1 Pupil plane H2 conjugate position L1 Laser light L2 signal light P1 fundamental wave P2 second harmonic R1 Reflected light

Claims

1. In a semiconductor measurement device for measuring nonlinear light generated in a sample, a laser light source that generates a fundamental wave having a first wavelength; an objective lens that focuses the fundamental wave on a sample surface; a wavelength filter for separating reflected light of the fundamental wave reflected by the sample from signal light generated by irradiating the fundamental wave on the sample, the signal light having a second wavelength different from the first wavelength; a detection unit for detecting the signal light separated by the wavelength filter; Equipped with The detection unit is arranged to detect the signal light generated by the same fundamental wave in two or more different emission directions from the sample. Semiconductor measuring equipment.

2. the detection unit includes a detector that detects an intensity of the signal light at a pupil plane of the objective lens; The semiconductor measurement device according to claim 1 .

3. The detector comprises: Located at a conjugate position of the pupil plane of the objective lens, having a plurality of light-sensitive surfaces; The semiconductor measuring device according to claim 2 .

4. The second wavelength is half the first wavelength. The semiconductor measurement device according to claim 1 .

5. the laser light source includes a pulsed laser light source that generates the fundamental wave in a pulse form, The pulse width of the fundamental wave is 1 picosecond or less. The semiconductor measurement device according to claim 1 .

6. a delay generator disposed on an optical path of the fundamental wave between the laser light source and the objective lens; The delay generator generates a time difference for one part of the fundamental wave to reach the sample relative to another part of the fundamental wave. The semiconductor measurement device according to claim 1 .

7. The delay generator comprises: a transparent member having a thickness distribution in the optical axis direction of the fundamental wave, The time difference is generated by a difference in optical path length of the fundamental wave transmitted through the transmitting member. The semiconductor measuring device according to claim 6 .

8. The delay generator comprises: a reflecting member having a distribution in height in the optical axis direction of the fundamental wave, generating the time difference by a difference in optical path length of the fundamental wave reflected by the reflecting member; The semiconductor measuring device according to claim 6 .

9. the detection unit includes a detector that detects the signal light generated by the fundamental wave having the time difference by dividing the signal light by the time difference, The semiconductor measuring device according to claim 6 .

10. the detection unit includes a detector having a plurality of light-sensitive surfaces; the number of said photosensitive surfaces is equal to the number of said time differences generated by said delay generator; each light receiving surface receives the signal light corresponding to the signal light of each time difference; The semiconductor measuring device according to claim 6 .

11. a polarization controller disposed on an optical path of the fundamental wave between the laser light source and the objective lens; The polarization controller controls the polarization state of the fundamental wave, The detection unit includes: A detector for detecting the signal light; an ellipsometer for analyzing the polarization state; having The semiconductor measurement device according to claim 1 .

12. the ellipsometer generates interference fringes on the detector that reflect the polarization state of the signal light; The semiconductor measurement device according to claim 11.

13. The polarization controller generates a specific polarization state on a pupil plane of the objective lens. The semiconductor measurement device according to claim 11.

14. The specific polarization state includes any of radial polarization, azimuthal polarization, and a combination of radial polarization and azimuthal polarization. The semiconductor measurement device according to claim 13.

15. further comprising an annular light shaper disposed on an optical path of the fundamental wave between the laser light source and the objective lens; The annular light shaper shapes the fundamental wave into an annular shape. The semiconductor measurement device according to claim 1 .

16. a light splitting unit disposed on an optical path of the fundamental wave between the laser light source and the objective lens; The optical splitting unit includes: Splitting the fundamental wave into two or more optical paths; adjusting the optical path length of the divided optical path; The semiconductor measurement device according to claim 1 .

17. The optical splitting unit includes: a beam splitter that splits the fundamental wave into equal amplitude parts; A mirror that reflects the fundamental wave; Including, The semiconductor measurement device according to claim 16.

18. the detection unit is a first detection unit, the wavelength filter includes a dichroic mirror; Further comprising a second detection unit that detects the reflected light separated from the signal light by the dichroic mirror. The semiconductor measurement device according to claim 1 .

19. The second detection unit is A detector for detecting the intensity of the fundamental wave; an ellipsometer that generates interference fringes on the detector that reflect the polarization state of the fundamental wave; having The semiconductor measurement device according to claim 18.

20. Further comprising a spatial phase modulator disposed on an optical path of the fundamental wave between the laser light source and the objective lens. The semiconductor measurement device according to claim 1 .

21. The optical axis of the objective lens is perpendicular to the sample surface. The semiconductor measurement device according to claim 1 .

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