Continuous wide spectrum analysis device for semiconductor measurement
By setting up cascaded spectral dispersive and collecting sub-devices in a grating spectrometer and utilizing zero-order optical multiplexing technology, the problem of low efficiency in continuous broadband detection of traditional grating spectrometers is solved, and efficient continuous broadband data acquisition is achieved.
Patent Information
- Application Number
- CN202511275469.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-08
- Publication Date
- 2025-11-14
AI Technical Summary
Traditional grating spectrometers are unable to meet the high-precision detection requirements of a continuous wide spectrum from the ultraviolet band to the infrared band (190 nm to 2500 nm).
By setting up nth-order and n+1th-order beam splitting and collecting devices, where the nth-order grating and the n+1th-order grating are parallel to each other, the nth-order grating diffracts the incident light and reflects the undiffracted zero-order light onto the n+1th-order grating, thus realizing the multiplexing of the zero-order light, and the n+1th-order grating diffracts the zero-order light, ensuring that the first-order diffracted light in a continuous wide spectrum is collected.
It improves the data acquisition efficiency within a continuous wide spectrum and achieves high-precision continuous wide spectrum detection.
Smart Images
Figure CN120948376A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of semiconductor measurement technology, and more specifically, to a continuous broadband spectral analysis device for semiconductor measurement. Background Technology
[0002] Currently, semiconductor metrology refers to the precise measurement of the physical structure and chemical composition of wafers and chips during semiconductor manufacturing. Measuring the physical structure of wafers and chips requires measuring the thickness of semiconductor optical films and key optical dimensions. Spectral ellipsometry is a primary non-contact measurement method, and a spectral analysis device is the core component for implementing this technique. Typically, spectral analysis devices use instruments similar to grating spectrometers to achieve spectral dispersion.
[0003] Traditional grating spectrometers are unable to meet the high-precision detection requirements of a continuous wide spectrum from the ultraviolet band to the infrared band (190 nanometers (nm) to 2500 nm) when performing spectral dispersion. Summary of the Invention
[0004] To address the aforementioned problems, the purpose of this application is to provide a continuous broadband spectral analysis device for semiconductor measurement.
[0005] In a first aspect, embodiments of this application provide a continuous broadband spectral analysis apparatus for semiconductor measurement, comprising: an nth-stage spectroscopic and collecting sub-device and an (n+1)th-stage spectroscopic and collecting sub-device arranged therebetween; wherein n=1 and 2 or n=1;
[0006] The nth-stage beam splitting and collecting sub-device includes an nth grating, and the (n+1)th-stage beam splitting and collecting sub-device includes an (n+1)th grating; the nth grating and the (n+1)th grating are parallel to each other;
[0007] The nth grating diffracts the incident light based on the spectral band corresponding to its nth blaze wavelength, obtaining first-order diffracted light in the spectral band corresponding to the nth blaze wavelength. At the same time, the nth grating reflects the zeroth-order light that has not been diffracted onto the (n+1)th grating. The first-order diffracted light in the spectral band corresponding to the nth blaze wavelength is collected by the nth-order beam splitter and collector to which the nth grating belongs.
[0008] The (n+1)th grating diffracts the incident zeroth-order light based on the spectral band corresponding to its (n+1)th blaze wavelength, obtaining first-order diffracted light in the spectral band corresponding to the (n+1)th blaze wavelength. The first-order diffracted light in the spectral band corresponding to the (n+1)th blaze wavelength is collected by the (n+1)th-order beam splitter and collector to which the (n+1)th grating belongs. The nth blaze wavelength is shorter than the (n+1)th blaze wavelength, and the spectral band corresponding to the (n+1)th blaze wavelength is partially the same as the spectral band corresponding to the nth blaze wavelength.
[0009] In the solution provided by the first aspect of the present application embodiments, an nth-level spectral splitting and collecting sub-device and an (n+1)th-level spectral splitting and collecting sub-device are arranged sequentially. The nth-level spectral splitting and collecting sub-device includes an nth grating, and the (n+1)th-level spectral splitting and collecting sub-device includes an (n+1)th grating. The nth grating and the (n+1)th grating are parallel to each other. The nth grating diffracts the incident light based on the spectral band corresponding to its nth blaze wavelength to obtain first-order diffracted light in the spectral band corresponding to the nth blaze wavelength, and reflects the undiffracted zero-order light onto the (n+1)th grating for diffraction. Compared with the method in related technologies where grating spectrometers directly discard unused zero-order light after spectral splitting, this method cleverly reuses the undiffracted zero-order light. While obtaining a continuous broadband spectrum, it also ensures that the first-order diffracted light in the continuous broadband spectrum generated by the nth grating and the (n+1)th grating can be collected simultaneously, thereby improving the data acquisition efficiency in the continuous broadband spectrum.
[0010] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description
[0011] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0012] Figure 1 A schematic diagram of a continuous broadband spectral analysis device for semiconductor measurement when n=1 is shown in an embodiment of this application.
[0013] Figure 2 The following is an illustration of the formula expressing the relationship between the horizontal and vertical spacing between the first and second gratings in a continuous broadband analytical apparatus for semiconductor measurement when n=1, provided in an embodiment of this application. , and A schematic diagram.
[0014] Figure 3 This application illustrates a continuous broadband spectral analysis apparatus for semiconductor measurement using a grating, as provided in an embodiment of the present application.
[0015] Figure 4 This illustration shows a schematic diagram of the band range effect achieved by the continuous broadband spectral analysis device for semiconductor measurement using a grating provided in an embodiment of this application.
[0016] Figure 5 A schematic diagram of the structure of the continuous broadband spectral analysis device for semiconductor measurement when n=2, provided in an embodiment of this application, is shown.
[0017] Figure 6 This illustration shows a schematic diagram of the band range effect achieved by the continuous wide-spectrum analysis device for semiconductor measurement when n=2, as provided in the embodiments of this application.
[0018] Figure 7 A schematic diagram of the structure of a spectroscopic ellipsometer having the above-described continuous broadband spectral analysis apparatus for semiconductor measurement provided in an embodiment of this application is shown.
[0019] Icons: 100, slit; 102, collimating lens; 104, first grating; 106, first focusing lens; 108, first charge-coupled device (CCD); 110, second grating; 112, second focusing lens; 114, second CCD; 116, PD focusing lens; 118, photodiode; 300, first grating; 302, second grating; 500, third grating; 502, third focusing lens; 504, third CCD; 700, broadband light source; 702, incident polarizer; 704, wafer; 706, receiving polarization analyzer; 708, continuous broadband analysis device for semiconductor measurement. Detailed Implementation
[0020] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.
[0021] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.
[0022] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0023] Currently, semiconductor metrology refers to the precise measurement of the physical structure and chemical composition of wafers and chips during the semiconductor manufacturing process. Measuring the physical structure of wafers and chips requires measuring the thickness of semiconductor optical films and key dimensions. Spectral ellipsometry is a primary non-contact measurement method, and the spectral analysis device is the core component for realizing this technique. Typically, spectral analysis devices employ spectrometers similar to grating spectrometers to achieve spectral dispersion.
[0024] Traditional grating spectrometers are unable to meet the high-precision detection requirements of a continuous wide spectrum from the ultraviolet band to the infrared band (190 nanometers (nm) to 2500 nm) when performing spectral dispersion.
[0025] Based on this, the following embodiments of this application propose a continuous broadband analysis device for semiconductor measurement. It comprises an nth-stage spectrometer and a (n+1)th-stage spectrometer and collector, each consisting of an nth-stage grating and a (n+1)th-stage grating. The nth and (n+1)th gratings are parallel to each other. The nth grating diffracts the incident light based on its own spectral band corresponding to its nth blaze wavelength, obtaining first-order diffracted light in the spectral band corresponding to the nth blaze wavelength. The undiffracted zero-order light is reflected onto the (n+1)th grating for diffraction. This cleverly reuses the undiffracted zero-order light, ensuring that while obtaining a continuous broadband spectrum, the first-order diffracted light within the continuous broadband spectrum generated by the nth and (n+1)th gratings can be simultaneously collected, thus improving the data acquisition efficiency within the continuous broadband spectrum.
[0026] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and embodiments.
[0027] Example
[0028] The city has implemented a continuous broadband spectral analysis device for semiconductor measurement, comprising: an nth-stage spectrometer and a (n+1)th-stage spectrometer and a collector, wherein n=1 and 2 or n=1.
[0029] The nth-stage beam splitting and collecting sub-device includes an nth grating, and the (n+1)th-stage beam splitting and collecting sub-device includes an (n+1)th grating; the nth grating and the (n+1)th grating are parallel to each other.
[0030] The nth grating diffracts the incident light based on the spectral band corresponding to its nth blaze wavelength, obtaining first-order diffracted light in the spectral band corresponding to the nth blaze wavelength. At the same time, the nth grating reflects the zeroth-order light that has not been diffracted onto the (n+1)th grating. The first-order diffracted light in the spectral band corresponding to the nth blaze wavelength is collected by the nth-order beam splitter and collector to which the nth grating belongs.
[0031] The (n+1)th grating diffracts the incident zeroth-order light based on the spectral band corresponding to its (n+1)th blaze wavelength, obtaining first-order diffracted light in the spectral band corresponding to the (n+1)th blaze wavelength. The first-order diffracted light in the spectral band corresponding to the (n+1)th blaze wavelength is collected by the (n+1)th-order beam splitter and collector to which the (n+1)th grating belongs. The nth blaze wavelength is shorter than the (n+1)th blaze wavelength, and the spectral band corresponding to the (n+1)th blaze wavelength is partially the same as the spectral band corresponding to the nth blaze wavelength.
[0032] Specifically, in order to collect the first-order diffraction light generated by the nth grating or the (n+1)th grating, the nth-order beam splitting and collecting sub-device and the (n+1)th-order beam splitting and collecting sub-device further include a focusing mirror and a charge-coupled device, respectively.
[0033] The focusing lens converges the first-order diffracted light generated by the nth grating or the (n+1)th grating onto the corresponding charge-coupled device, and collects the first-order diffracted light through the charge-coupled device.
[0034] The focusing lens mentioned above can be, but is not limited to: a spherical mirror, a conical mirror, an aspherical mirror, a lens, or a lens group.
[0035] Specifically, the continuous broadband spectral analysis device for semiconductor measurement also includes a narrow slit and a collimating lens.
[0036] The incident light passes through the narrow slit and is incident on the collimating lens. After being collimated by the collimating lens, it is incident on the first grating of the first-stage beam splitter and collector in the nth-stage beam splitter and collector and the (n+1)th-stage beam splitter and collector.
[0037] Optionally, the nth grating and the (n+1)th grating can be truss gratings.
[0038] Optionally, in order to multiplex and transmit the zero-order light, the nth-order beam splitter and collector and the (n+1)th-order beam splitter and collector are in a series linear cascade structure.
[0039] The horizontal and vertical spacing between the nth grating and the (n+1)th grating satisfy the following formula 1:
[0040] (1)
[0041] Where L represents the horizontal spacing between the nth grating and the (n+1)th grating; h represents the vertical spacing between the nth grating and the (n+1)th grating; This represents the angle of incidence when the zeroth order light reflected from the nth grating is incident on the (n+1)th grating; This represents the diffraction angle of the nth grating.
[0042] Optionally, It is determined by the incident angle of the light rays incident on the nth grating and the blaze angle of the nth grating.
[0043] In the continuous broadband spectral analysis apparatus for semiconductor measurement proposed in this embodiment, the following formula 2 is used to obtain... :
[0044] (2)
[0045] in, This represents the angle of incidence of the light ray when it hits the nth grating; This represents the blaze angle of the nth grating.
[0046] The ratio of the zero-order light reflected from the nth grating to the (n+1)th grating to the incident light received by the nth grating is dynamically adjusted between 0.1 and 0.9. This effectively balances the overall spectral efficiency by rationally allocating the ratio of zero-order light to diffracted light.
[0047] Here, the incident light can be white light or zero-order light.
[0048] The continuous broadband spectral analysis apparatus for semiconductor measurement proposed in this application will be further described using the following Examples 1 to 3:
[0049] Example 1
[0050] When n=1, the continuous broadband analysis device for semiconductor measurement includes: a first-stage spectrometer and a second-stage spectrometer and a second-stage spectrometer and a second-stage spectrometer, thereby achieving two-stage spectrometer.
[0051] In one embodiment, the first blaze wavelength of the first grating in the first-stage spectral splitting and collecting device is 550 nm, and the spectral band corresponding to the first blaze wavelength is 190 nm to 900 nm; the second blaze wavelength of the second grating in the second-stage spectral splitting and collecting device is 1700 nm, and the spectral band corresponding to the second blaze wavelength is 890 nm to 2500 nm.
[0052] See Figure 1 The diagram shows a continuous broadband spectral analysis device for semiconductor measurement when n=1. The continuous broadband spectral analysis device for semiconductor measurement when n=1 includes: a slit 100, a collimating lens 102, a first grating 104, a first focusing lens 106, a first charge-coupled device 108, a second grating 110, a second focusing lens 112, and a second charge-coupled device 114.
[0053] Slit 100 is used to control the incident path and range of light. The light is white light with a spectral range of 190 nm to 2500 nm.
[0054] The first grating 104 and the second grating 110 are parallel to each other.
[0055] Collimating lens 102 is used to convert diverging light into parallel light, which facilitates subsequent beam splitting operations.
[0056] The first grating 104 is used to split the light (i.e., diffract a portion of the light to obtain first-order diffracted light), so that the first-order diffracted light of different wavelengths propagates at different angles, and at the same time, it reflects the other part of the light that has not been diffracted, the zero-order light, to the second grating. The spectral range of the zero-order light is from 190nm to 2500nm.
[0057] First focusing mirror 106: focuses the first-order diffracted light obtained by the first grating 104 onto the first charge-coupled device 108.
[0058] The first charge-coupled device 108 is used to collect the first-order diffracted light obtained by the first grating 104.
[0059] The second grating 110 is used to split the zero-order light reflected by the first grating 104, thereby expanding the spectral range and enabling first-order diffracted light of different wavelengths to propagate at different angles.
[0060] The second focusing mirror 112 is used to focus the first-order diffracted light obtained by the second grating 110 onto the second charge-coupled device 114.
[0061] The second charge-coupled device 114 is used to collect the first-order diffracted light obtained by the second grating 110.
[0062] Optionally, the second grating 110 is used to reflect the undiffracted zero-order light to the PD focusing mirror 116 while splitting the light. The undiffracted zero-order light is converged by the PD focusing mirror 116 and then incident on the photodiode 118. The photodiode 118 is used to monitor the intensity fluctuation of the incident light. It can also be used for triangulation autofocus (real-time monitoring of the surface height of the detection surface, adjusting the distance between the slit and the collimating mirror by an electric displacement stage to ensure that the incident light is always collimated and focused on the detection surface).
[0063] The parameters of each optical element in the continuous broadband analysis device used for semiconductor measurement when n=1 are shown in Table 1:
[0064] Table 1
[0065] Optical elements / units Radius / millimeters (mm) Air gap / mm Eccentricity / mm Tilt / ° Slit 300 Collimating lens 600 250 7 First grating 32 61 22 First focusing lens 600 292.511 120 First charge-coupled device The spacing between the first grating and the second grating 320 Second grating 350 122 22 Second focusing lens 600 290 160 3 Second charge-coupled device
[0066] See Figure 2 The formula shown, when n=1, expresses the relationship between the horizontal and vertical spacing between the first and second gratings in a continuous broadband analytical apparatus used for semiconductor measurement. , and The schematic diagram shows that the relationship between the horizontal and vertical spacing between the first and second gratings can be obtained through Formula 1 above. The specific relationship is shown in Formula 1 above, and will not be repeated here.
[0067] In a continuous broadband analysis device for semiconductor measurement with n=1, the ratio of the zero-order light reflected from the first grating to the second grating to the incident light received by the first grating is shown in Table 2 below. The ratio of the zero-order light of the first grating is dynamically adjusted between 0.1 and 0.9 to achieve a uniform and balanced spectral efficiency for different ratios of ultraviolet, visible and infrared light.
[0068] Here, the incident light received by the first grating is white light.
[0069] Table 2
[0070] Spectrophotometer ratio 1 Spectrophotometer ratio 2 Spectrophotometer ratio 3 First grating (excluding the distribution ratio of diffracted light from the zeroth order) 0.1 0.5 0.9 The second grating (the distribution ratio of the zero-order light of the first grating) 0.9 0.5 0.1
[0071] Example 2
[0072] Optionally, the first grating can be replaced by a first grating and the second grating can be replaced by a second grating, so that the first grating is used in the first-stage beam splitting and collecting sub-device and the second grating is used in the second-stage beam splitting and collecting sub-device.
[0073] The first and second gratings each include a rotatable grating structure and three diffraction grating units disposed on the grating structure.
[0074] In one embodiment, the spectral ranges corresponding to the three diffraction grating units disposed on the first tower grating are 190nm to 600nm, 680nm to 1500nm, and 1650nm to 2150nm, respectively.
[0075] The three diffraction grating units set on the second tower grating correspond to the spectral ranges of 270nm to 650nm, 900nm to 1650nm, and 2000nm to 2600nm, respectively.
[0076] See Figure 3 The continuous broadband analysis apparatus for semiconductor measurement using a grating shown includes: a slit 100, a collimating lens 102, a first grating 300, a first focusing lens 106, a first charge-coupled device 108, a second grating 302, a second focusing lens 112, and a second charge-coupled device 114.
[0077] The function of the first grating 300 is similar to that of the first grating 104 in Example 1, and will not be repeated here.
[0078] The function of the second grating 302 is similar to that of the second grating 110 in Example 1, and will not be repeated here.
[0079] See Figure 4 The diagram illustrates the effect of a continuous broadband spectral analyzer for semiconductor measurement using a grating to achieve a wide spectral range. By using a grating for semiconductor measurement, this continuous broadband spectral analyzer can perform spectral dispersion and zero-order optical multiplexing, achieving, for example... Figure 4 The effect shown is within the band range, but it is not limited to this combination of band ranges. It can be dynamically adjusted. Each tower wheel carries three gratings, which can realize three wavelength bandwidth combinations and switch freely.
[0080] Example 3
[0081] When n=2, the continuous broadband analysis device for semiconductor measurement includes: a first-stage spectrometer, a second-stage spectrometer, and a third-stage spectrometer arranged accordingly, thereby achieving three-stage spectrometer.
[0082] In one embodiment, the first blaze wavelength of the first grating in the first-stage spectral splitting and collecting sub-device is 400 nm, and the spectral band corresponding to the first blaze wavelength is 190 nm to 600 nm; the second blaze wavelength of the second grating in the second-stage spectral splitting and collecting sub-device is 650 nm, and the spectral band corresponding to the second blaze wavelength is 400 nm to 900 nm; the third blaze wavelength of the third grating in the third-stage spectral splitting and collecting sub-device is 1250 nm, and the spectral band corresponding to the second blaze wavelength is 860 nm to 900 nm.
[0083] See Figure 5 The schematic diagram shown is of a continuous broadband spectral analysis device for semiconductor measurement when n=2. Based on the continuous broadband spectral analysis device for semiconductor measurement when n=1 shown in Example 1, the continuous broadband spectral analysis device for semiconductor measurement when n=2, in addition to the optical elements such as slit 100, collimating lens 102, first grating 104, first focusing lens 106, first charge-coupled device 108, second grating 110, second focusing lens 112, and second charge-coupled device 114, also includes: third grating 500, third focusing lens 502, and third charge-coupled device 504.
[0084] The third grating 500 is parallel to the first grating 104 and the second grating 110, respectively.
[0085] The third grating 500 is used to split the zero-order light reflected by the second grating 110, thereby expanding the spectral range and enabling first-order diffracted light of different wavelengths to propagate at different angles.
[0086] The third focusing mirror 502 is used to focus the first-order diffracted light obtained by the third grating 500 onto the third charge-coupled device 504.
[0087] The third charge-coupled device 504 is used to collect the first-order diffracted light obtained by the third grating 502.
[0088] The parameters of each optical element in the continuous broadband analysis device used for semiconductor measurement when n=2 are shown in Table 3:
[0089] Table 3
[0090] Optical elements / units Radius / millimeters (mm) Air gap / mm Eccentricity / mm Tilt / ° Slit 300 Collimating lens 600 250 7 First grating 32 61 22 First focusing lens 600 292.511 120 First charge-coupled device The spacing between the first grating and the second grating 320 Second grating 350 122 22 Second focusing lens 600 290 160 3 Second charge-coupled device The spacing between the second and third gratings 320 Third grating 177 22 Third focusing lens 600 269.25 110 25 Third charge-coupled device
[0091] The relationship between the horizontal and vertical spacing of the first grating 104 and the second grating 110 is consistent with the relationship between the horizontal and vertical spacing of the first grating 104 and the second grating 110 in Example 1 above. The relationship between the horizontal and vertical spacing of the third grating 500 and the second grating 110 can also be determined using Formula 1 above, and will not be elaborated further here.
[0092] In a continuous broadband analysis device used for semiconductor measurement when n=2, the ratio of the zero-order light reflected from the first grating to the second grating to the incident light received by the first grating, and the ratio of the zero-order light reflected from the second grating to the third grating to the incident light received by the second grating are shown in Table 4 below. The ratio of the zero-order light of the first grating to the second grating is dynamically adjusted between 0.1 and 0.9 to achieve a uniform and balanced spectral efficiency for different ratios of ultraviolet, visible, and infrared light.
[0093] Here, the incident light received by the first grating is white light. The incident light received by the second grating is zero-order light.
[0094] Table 4
[0095] Spectrophotometer ratio 1 Spectrophotometer ratio 2 Spectrophotometer ratio 3 First grating (excluding the distribution ratio of diffracted light from the zeroth order) 0.1 0.5 0.8 Second grating (excluding the distribution ratio of diffracted light from the zeroth order) 0.3 0.25 0.1 The third grating (the distribution ratio of the zero-order light of the second grating) 0.6 0.25 0.1
[0096] See Figure 6 The diagram shows the effect of a continuous broadband analyzer for semiconductor measurement when n=2, demonstrating the desired spectral range. This analyzer performs third-order beam splitting and zero-order multiplexing of the incident light, enabling the following: Figure 6 The effect shown is within the range of bands, but it is not limited to this combination of bands and can be dynamically adjusted.
[0097] Thus far, the continuous broadband spectral analysis apparatus for semiconductor measurement proposed in this application has been described in detail through Examples 1 to 3 above.
[0098] The continuous broadband analytical device for semiconductor measurement proposed in this application, based on a cascaded structure of zero-order optical multiplexing, enables simultaneous high signal-to-noise ratio acquisition across a continuous broadband spectrum. Furthermore, by rationally allocating the ratio of zero-order light to diffracted light, the overall spectral efficiency is effectively balanced. Its innovation lies in cleverly utilizing the zero-order light separated by a grating, cascading it to the next grating for continued use, and employing gratings with different line pairs to adapt to different wavelength ranges, thereby effectively expanding the spectral range.
[0099] Further, see Figure 7 The schematic diagram shown is of a spectroscopic ellipsometer having the above-mentioned continuous wide-spectrum analysis device for semiconductor measurement. The continuous wide-spectrum analysis device for semiconductor measurement proposed in this application is applied to the spectroscopic ellipsometer for measuring semiconductor film thickness and optical critical dimension OCD.
[0100] like Figure 7 As shown, the spectral ellipsometer proposed in this embodiment includes: a broadband light source 700 emitting white light covering deep ultraviolet to visible to near infrared; an incident polarization device 702 converging the incident white light to form a focused beam incident on the surface of a wafer 704; and a receiving polarization detector 706 used to receive the white light after it has passed through the wafer surface.
[0101] The incident polarizing device 702 includes a polarizer and a focusing lens. The polarizer is used to form light with a specific polarization state. The receiving polarization measuring device 706 includes a polarizer and a receiving lens. The polarizer is used to modulate the light beam into white light with a specific polarization state and to incident the modulated light beam into the continuous broadband spectrum analysis device 708 for semiconductor measurement.
[0102] In summary, this embodiment proposes a continuous broadband spectrum analysis device for semiconductor measurement. It comprises an nth-stage and an (n+1)th-stage spectrometer and a collection device, each consisting of an nth-stage and an (n+1)th-stage grating. The nth and (n+1)th gratings are parallel to each other. The nth grating diffracts the incident light based on its own spectral band corresponding to its nth blaze wavelength, obtaining first-order diffracted light in that band. The undiffracted zero-order light is reflected onto the (n+1)th grating for further diffraction. Compared to related technologies where grating spectrometers discard unused zero-order light after spectral dispersion, this device cleverly reuses the undiffracted zero-order light. While obtaining a continuous broadband spectrum, it also ensures that the first-order diffracted light within the continuous broadband spectrum generated by the nth and (n+1)th gratings can be simultaneously collected, thus improving the data acquisition efficiency within the continuous broadband spectrum.
[0103] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. A continuous broadband spectral analysis device for semiconductor measurement, characterized in that, include: The nth-stage spectral splitting and collecting sub-devices and the (n+1)th-stage spectral splitting and collecting sub-devices are configured accordingly; where n=1 and 2 or n=1; The nth-stage beam splitting and collecting sub-device includes an nth grating, and the (n+1)th-stage beam splitting and collecting sub-device includes an (n+1)th grating; the nth grating and the (n+1)th grating are parallel to each other; The nth grating diffracts the incident light based on the spectral band corresponding to its nth blaze wavelength, obtaining first-order diffracted light in the spectral band corresponding to the nth blaze wavelength. At the same time, the nth grating reflects the zeroth-order light that has not been diffracted onto the (n+1)th grating. The first-order diffracted light in the spectral band corresponding to the nth blaze wavelength is collected by the nth-order beam splitter and collector to which the nth grating belongs. The (n+1)th grating diffracts the incident zeroth-order light based on the spectral band corresponding to its (n+1)th blaze wavelength, obtaining first-order diffracted light in the spectral band corresponding to the (n+1)th blaze wavelength. The first-order diffracted light in the spectral band corresponding to the (n+1)th blaze wavelength is collected by the (n+1)th-order beam splitter and collector to which the (n+1)th grating belongs. The nth blaze wavelength is shorter than the (n+1)th blaze wavelength, and the spectral band corresponding to the (n+1)th blaze wavelength is partially the same as the spectral band corresponding to the nth blaze wavelength.
2. The continuous broadband spectral analysis apparatus for semiconductor measurement according to claim 1, characterized in that, The horizontal and vertical spacing between the nth grating and the (n+1)th grating satisfy the following formula: ； Where L represents the horizontal spacing between the nth grating and the (n+1)th grating; h represents the vertical spacing between the nth grating and the (n+1)th grating; This represents the angle of incidence when the zeroth order light reflected from the nth grating is incident on the (n+1)th grating; This represents the diffraction angle of the nth grating.
3. The continuous broadband spectral analysis apparatus for semiconductor measurement according to claim 2, characterized in that, It is determined by the incident angle of the light rays incident on the nth grating and the blaze angle of the nth grating.
4. The continuous broadband spectral analysis apparatus for semiconductor measurement according to claim 3, characterized in that, The following formula is used to obtain... : ； in, This represents the angle of incidence of the light ray when it hits the nth grating; This represents the blaze angle of the nth grating.
5. The continuous broadband spectral analysis apparatus for semiconductor measurement according to claim 1, characterized in that, The ratio of the zero-order light reflected from the nth grating to the (n+1)th grating to the incident light received by the nth grating is dynamically adjusted between 0.1 and 0.
9.
6. The continuous broadband spectral analysis apparatus for semiconductor measurement according to claim 1, characterized in that, The nth-level beam splitting and collecting sub-device and the (n+1)th-level beam splitting and collecting sub-device further include: a focusing mirror and a charge-coupled device; The focusing lens converges the first-order diffracted light generated by the nth grating or the (n+1)th grating onto the corresponding charge-coupled device, and collects the first-order diffracted light through the charge-coupled device.
7. The continuous broadband spectral analysis apparatus for semiconductor measurement according to claim 1, characterized in that, Also includes: Narrow slits and collimating lenses; The incident light passes through the narrow slit and is incident on the collimating lens. After being collimated by the collimating lens, it is incident on the first grating of the first-stage beam splitter and collector in the nth-stage beam splitter and collector and the (n+1)th-stage beam splitter and collector.
8. The continuous broadband spectral analysis apparatus for semiconductor measurement according to claim 1, characterized in that, The nth grating and the (n+1)th grating can be truss gratings.
9. The continuous broadband spectral analysis apparatus for semiconductor measurement according to claim 1, characterized in that, The nth-stage beam splitting and collecting sub-device and the (n+1)th-stage beam splitting and collecting sub-device are in a series linear cascade structure.