Virtual reference film generation method, oxygen concentration measurement method and readable storage medium

Abstract

The invention relates to the technical field of semiconductors, and provides a virtual reference sheet generation method, an oxygen concentration measurement method and a readable storage medium, and the virtual reference sheet generation method comprises the following steps: S1, measuring an infrared absorption spectrum curve of a physical reference sheet through a Fourier transform spectroscopic analysis method; s2, selecting a wave band corresponding to an absorption peak in the infrared absorption spectrum curve; and S3, re-fitting the infrared absorption spectrum curve to enable the curve peak value of the fitted infrared absorption spectrum curve corresponding to the wave band position to be smaller than the absorption peak, and taking the fitted infrared absorption spectrum curve as the infrared absorption spectrum curve of the virtual reference sheet. The virtual reference sheet can eliminate the influence of a small amount of oxygen in a physical reference sheet on the detection precision so as to improve the detection precision.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a virtual reference slice generation method, an oxygen concentration measurement method, and a readable storage medium. Background Art

[0002] The oxygen content of silicon is a critical metric required for acceptance, process monitoring, and research and development in the silicon material and device manufacturing industry. Currently, the industry primarily measures oxygen content in silicon wafers through Fourier Transform Infrared (FTIR) spectroscopy. FTIR technology is based on the absorption properties of infrared light. Different chemical bonds or functional groups absorb infrared light at different wavelengths. When infrared light strikes the surface of a silicon wafer, the chemical bonds within the wafer absorb specific wavelengths, forming absorption peaks. By analyzing the position and intensity of these absorption peaks, the chemical composition and structure of the silicon wafer surface can be determined.

[0003] The infrared absorption spectrum generated by infrared light hitting the surface of a silicon wafer includes the influence of the silicon lattice. Therefore, when analyzing the infrared absorption spectrum, the influence of the silicon lattice absorption must be subtracted first. A common approach currently used is to use an oxygen-free physical reference silicon wafer as a standard wafer. This infrared absorption spectrum of the wafer under test is then subtracted from the infrared absorption spectrum of the wafer under test to obtain the spectral absorption signal of the oxygen content. However, during the manufacturing process of the physical reference silicon wafer, it is difficult to ensure that the oxygen content is absolutely zero. When the physical reference silicon wafer itself contains a small amount of oxygen, the accuracy of the measurement of the low-oxygen silicon wafer is affected, resulting in lower measurement precision.

[0004] Based on this, a virtual reference slice generation method, an oxygen concentration measurement method and a readable storage medium are needed to replace the original physical reference slice with a virtual reference slice to improve the detection accuracy of the oxygen content of the silicon wafer. Summary of the Invention

[0005] The present invention provides a method for generating a virtual reference film, a method for measuring oxygen concentration, and a readable storage medium. The virtual reference film can eliminate the influence of a small amount of oxygen in a physical reference film on the detection accuracy. On the one hand, it can detect low concentrations of oxygen content, and on the other hand, it helps to improve the detection accuracy.

[0006] The virtual reference slice generation method comprises the following steps:

[0007] S1: Measure the infrared absorption spectrum of the physical reference film by Fourier transform spectroscopy;

[0008] S2: Select the wavelength band corresponding to the absorption peak in the infrared absorption spectrum curve;

[0009] S3: refitting the infrared absorption spectrum curve so that the peak value of the fitted infrared absorption spectrum curve corresponding to the wavelength band position is smaller than the absorption peak, and using the fitted infrared absorption spectrum curve as the infrared absorption spectrum curve of the virtual reference film.

[0010] Optionally, refitting the infrared absorption spectrum curve in step S3 includes the following steps:

[0011] S3-1: selecting a plurality of characteristic anchor points on the infrared absorption spectrum curve, wherein at least two of the characteristic anchor points are two end points of the band, and the remaining characteristic anchor points are located outside the band;

[0012] S3-2: Reconstruct the infrared absorption spectrum curve based on discrete points.

[0013] Optionally, in step S3-1, the remaining characteristic anchor points are arranged on both sides of the wavelength band along the coordinate direction of the wavelength.

[0014] Optionally, the re-fitting of the infrared absorption spectrum curve in step S3 further includes the following steps:

[0015] S3-3: Set a goodness-of-fit threshold. If the goodness of fit of the reconstructed infrared absorption spectrum curve is less than the goodness-of-fit threshold, execute step S3-1.

[0016] Optionally, selecting a plurality of characteristic anchor points on the infrared absorption spectrum curve in step S3-1 includes the following steps:

[0017] A fitting segment is selected on the infrared absorption spectrum curve, where the fitting segment includes the waveband, and a plurality of characteristic anchor points are selected on the fitting segment, where at least two characteristic anchor points are two endpoints of the fitting segment.

[0018] Optionally, in step S3-3, if the goodness of fit is less than a goodness of fit threshold, when step S3-1 is re-executed, the position of the feature anchor point and / or the number of the feature anchor points are changed.

[0019] Optionally, the virtual reference slice generation method further includes step S4;

[0020] S4: The fitted infrared absorption spectrum curve is stored in the database and associated with the device number.

[0021] Optionally, before step S2, the infrared absorption spectrum curve is further smoothed.

[0022] The present invention also provides an oxygen concentration measurement method, comprising the following steps:

[0023] S1: Measure the infrared absorption spectrum curve of the test piece by Fourier transform spectroscopy;

[0024] S2: subtracting the infrared absorption spectrum curve of the virtual reference piece from the infrared absorption spectrum curve of the piece to be tested to obtain a final infrared absorption spectrum curve, wherein the infrared absorption spectrum curve of the virtual reference piece is obtained by the virtual reference piece generation method described above;

[0025] S3: Calculate the oxygen concentration of the test piece based on the final infrared absorption spectrum curve.

[0026] The present invention also provides a readable storage medium having a program stored thereon, and when the program is executed, the virtual reference slice generation method is executed.

[0027] In the virtual reference plate generation method of the present invention, the absorption peak of the infrared absorption spectrum curve corresponding to the virtual reference plate is reduced. This curve removes the influence of oxygen in the reference plate, resulting in a more pronounced absorption peak in the resulting differential spectrum curve. Even if the oxygen content of the test plate is relatively low, the measured differential spectrum curve still has a significant absorption peak. After using the infrared absorption spectrum curve of the virtual reference plate, the peak signal of the hypoxic sample is significantly strengthened, and the oxygen absorption signal is maximized, making the detection process more sensitive to infrared spectral absorption. This not only improves detection accuracy, but also allows the detection of low concentrations of oxygen in the test plate.

[0028] The use of this virtual reference plate optimizes the infrared absorption spectrum of the reference plate while ensuring accuracy, maximizing the oxygen signal extracted from the silicon wafer's infrared absorption spectrum and improving oxygen detection capabilities. Furthermore, the virtual reference plate replaces the physical reference plate, maximizing the oxygen signal through mathematical separation. This ensures high detection accuracy, improves detection efficiency, and reduces material costs. The use of the virtual reference plate is also compatible with existing FTIR equipment, eliminating the need for hardware modification. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a measurement curve diagram using a physical reference piece;

[0030] Figure 2 A virtual reference slice curve diagram according to an embodiment of the present invention;

[0031] Figure 3 A measurement curve diagram using a virtual reference sheet according to an embodiment of the present invention;

[0032] Figure 4 This is a measurement curve diagram of various oxygen concentrations when a physical reference sheet is used;

[0033] Figure 5 This is a measurement curve diagram of various oxygen concentrations when a virtual reference sheet is used;

[0034] Figure 6This is the oxygen concentration interval diagram measured by Fourier infrared spectrometer. DETAILED DESCRIPTION

[0035] The virtual reference slice generation method proposed in the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become more apparent from the following description. It should be noted that the accompanying drawings are highly simplified and not to exact scale, and are intended solely to facilitate and clearly illustrate the embodiments of the present invention.

[0036] In the present invention, "outer diameter" and "inner diameter" for circular structures correspond to the diameter size. For non-circular structures, the inner diameter refers to the diameter of its inscribed circle, and the outer diameter refers to the diameter of its circumscribed circle. "Axial direction" for a cylindrical rod body corresponds to the direction of its axis. For a non-cylindrical rod body, the axial direction corresponds to the length direction of the rod body.

[0037] As used in the present invention, the singular forms "a", "an", and "the" include plural referents. The term "or" is generally used to include "and / or", the term "several" is generally used to include "at least one", and the term "at least two" is generally used to include "two or more". In addition, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, features specified as "first", "second", and "third" may explicitly or implicitly include one or at least two of the features. In addition, as used in the present invention, "mounted", "connected", "connected", and one element "disposed" on another element should be understood broadly and generally only indicate that there is a connection, coupling, mating, or transmission relationship between the two elements, and the connection, coupling, mating, or transmission between the two elements can be direct or indirect through an intermediate element. It should not be understood to indicate or imply a spatial positional relationship between the two elements, that is, one element can be in any orientation such as inside, outside, above, below, or to the side of another element, unless the content clearly indicates otherwise. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In addition, directional terms such as above, below, up, down, upward, downward, left, right, etc. are used with respect to the exemplary embodiments as they are shown in the figures, with the upward or upper direction being toward the top of the corresponding figure and the downward or lower direction being toward the bottom of the corresponding figure.

[0038] Combine Figure 1 As shown, Figure 1 The horizontal axis is the wave number (which can also be converted to wavelength), the vertical axis is the infrared light absorption rate, and the curve represents the absorption rate when infrared light of different wavelengths is irradiated on the object being measured;

[0039] Figure 1 The black curve in the middle is the infrared absorption spectrum curve measured by the test piece, the red curve is the infrared absorption spectrum curve corresponding to the physical reference piece, which is used to refer to the infrared absorption spectrum curve of the silicon lattice absorption. The orange curve is the differential spectrum curve obtained by subtracting the red curve from the black curve. The orange curve is the infrared absorption spectrum curve after eliminating the influence of silicon lattice absorption from the black curve. Therefore, the orange curve can be used to calculate the oxygen content in the test piece.

[0040] Since it is difficult to ensure that the oxygen content of the physical reference film is absolutely zero. When the physical reference film itself contains a small amount of oxygen, the infrared absorption spectrum curve corresponding to the physical reference film ( Figure 1 The red curve in the figure will be distorted. Figure 1 As shown, the red curve has an absorption peak, which is caused by the oxygen content in the physical reference piece. Therefore, based on the infrared absorption spectrum curve corresponding to the physical reference piece ( Figure 1 The differential spectrum curve (orange curve) obtained by comparing the red curve in the figure will also be distorted, which will affect the accuracy of the measurement of low-oxygen silicon wafers and reduce the measurement precision. In addition, because the physical reference wafer itself contains oxygen, the actual oxygen content of general commercial physical reference wafers is usually greater than 1×10 15 atoms / cm 3 When testing silicon wafers with low oxygen concentration (e.g. oxygen content less than 5×10 16 atoms / cm 3 ) will result in significant errors. Existing methods cannot eliminate the interference of the reference plate's own oxygen peak, resulting in a limited detection limit. Therefore, when the oxygen content of the test plate drops below a certain level, it will be impossible to measure the oxygen content using the physical reference plate as a reference.

[0041] Based on this, this embodiment provides a method for generating a virtual reference slice, including the following steps:

[0042] S1: Determine the infrared absorption spectrum curve of the physical reference piece by Fourier transform spectroscopy; Figure 2 As shown, Figure 2 The horizontal axis represents the wave number (which can also be converted to wavelength), and the vertical axis represents the infrared light absorptivity. The black curve represents the infrared absorption spectrum curve when infrared light is irradiated on the physical reference film. This curve is the full-band absorption spectrum data. This curve includes the influence of the oxygen element in the physical reference film. Its absorption peak is the influence of the oxygen element on the absorptivity. At this time, the absorption peak is eliminated by the following steps to eliminate the influence of the oxygen element in the physical reference film on the infrared absorption spectrum curve;

[0043] S2: Select the band corresponding to the absorption peak in the infrared absorption spectrum curve. The band should contain the absorption peak. Figure 2The middle absorption peak corresponds to point A, and the two endpoints of the selected band are points B and C, and the band contains the absorption peak.

[0044] S3: refitting the infrared absorption spectrum curve so that the peak value of the fitted infrared absorption spectrum curve corresponding to the wavelength band position is smaller than the absorption peak, and using the fitted infrared absorption spectrum curve as the infrared absorption spectrum curve of the virtual reference film.

[0045] Combine Figure 2 As shown, the refitted infrared absorption spectrum curve corresponds to the red curve 2. The curve corresponding to the band (between point B and point C) in the red curve becomes smooth. After refitting, the peak value of the interval between point B and point C is smaller than the absorption peak (point A). By refitting, the absorption peak is reduced, thereby reducing the influence of the oxygen element in the reference film on the infrared absorption spectrum curve; the refitted infrared absorption spectrum curve (red line) can be stored as the infrared absorption spectrum curve of the virtual reference film.

[0046] Combine Figure 3 As shown, Figure 3 The black curve in the middle is the infrared absorption spectrum curve measured by the test piece, the red curve is the infrared absorption spectrum curve corresponding to the virtual reference piece, and the orange curve is the differential spectrum curve obtained by subtracting the red curve from the black curve. The orange curve is the infrared absorption spectrum curve after eliminating the influence of silicon lattice absorption from the red curve. Therefore, the orange curve can be used to calculate the oxygen content in the test piece.

[0047] Figure 3 In the infrared absorption spectrum curve corresponding to the virtual reference film, the absorption peak becomes smaller and the curve removes the influence of oxygen elements. Figure 3 The differential spectrum curve (orange curve) obtained from the virtual reference sample exhibits a significant absorption peak, even when the oxygen content of the sample under test is low. Using the infrared absorption spectrum curve of the virtual reference sample significantly strengthens the peak signal of the hypoxic sample, maximizing the preservation of the oxygen absorption signal. This results in greater sensitivity to infrared absorption during the test process, improving detection accuracy while also enabling the detection of low oxygen concentrations in the sample under test.

[0048] Please continue to refer to Figure 4 and Figure 5 As shown, Figure 4 The graph below shows silicon wafer oxygen concentrations at 3 ppma, 5 ppma, 7 ppma, 10 ppma, 12 ppma, and 15 ppma, based on measurements from a physical reference wafer. PPMa represents oxygen concentration, representing the percentage of oxygen atoms per million atoms. For example, 10 ppma means 10 out of every million atoms are oxygen.

[0049] like Figure 4 As shown, the infrared absorption spectrum curve of the silicon wafer with each oxygen concentration is subtracted from the infrared absorption spectrum curve corresponding to the physical reference wafer ( Figure 4 The final infrared absorption spectrum curve (black curve on the right) was obtained Figure 4 For silicon wafers with higher oxygen concentrations (5ppma, 7ppma, 10ppma, 12ppma, and 15ppma), the final infrared absorption spectrum curve has a more distinct absorption peak. However, due to the influence of impurities in the physical reference wafer, the absorption peak of the final infrared absorption spectrum curve is not distinct for silicon wafers with lower oxygen concentrations (3ppma). Therefore, the detection accuracy is poor for silicon wafers with oxygen contents below 3ppma.

[0050] Figure 5 The graph in FIG. 3 shows the curve of the silicon wafer detected based on the virtual reference wafer when the oxygen concentration is 3 ppma, 5 ppma, 7 ppma, 10 ppma, 12 ppma, and 15 ppma.

[0051] like Figure 5 As shown, the infrared absorption spectrum curves of the silicon wafers with different oxygen concentrations are subtracted from the infrared absorption spectrum curves corresponding to the virtual reference wafer ( Figure 5 The final infrared absorption spectrum curve ( Figure 5 For silicon wafers with higher oxygen concentrations (5ppma, 7ppma, 10ppma, 12ppma, and 15ppma), the final infrared absorption spectrum curve has a more pronounced absorption peak, due to the influence of impurities in the virtual reference wafer. For silicon wafers with lower oxygen concentrations (3ppma), the final infrared absorption spectrum curve also has a more pronounced absorption peak. The peak signal of the low-oxygen silicon wafer is significantly stronger, and the oxygen absorption signal is maximized. Therefore, the virtual reference wafer can be used to detect silicon wafers with low oxygen concentrations.

[0052] like Figure 6 As shown, Figure 6 This is the oxygen concentration interval diagram measured by Fourier infrared spectrometer.

[0053] The horizontal axis represents the oxygen concentration detected by the physical reference piece, and the vertical axis represents the oxygen concentration detected by the virtual reference piece.

[0054] Figure 6 In the figure, the detection curve corresponds to the horizontal axis. When the oxygen concentration is as low as 3.28 ppma, the detection curve becomes vertical (see the box). Therefore, the lowest concentration that can be detected using the physical reference film is about 3.28 ppma.

[0055] Figure 6In the detection curve, the lowest oxygen concentration can be less than 2 ppma, corresponding to the vertical axis. Therefore, the lowest concentration that can be detected using the virtual reference film is even lower. Furthermore, the maximum oxygen concentration corresponding to the vertical axis of the detection curve is similar to the maximum oxygen concentration corresponding to the horizontal axis. Therefore, the virtual reference film still has the ability to detect higher oxygen concentrations as a physical reference film, verifying that the virtual reference film detection method is effective in cases with higher oxygen concentrations.

[0056] The use of this virtual reference plate optimizes the infrared absorption spectrum of the reference plate while ensuring accuracy, maximizing the oxygen signal extracted from the silicon wafer's infrared absorption spectrum and improving oxygen detection capabilities. Furthermore, the virtual reference plate replaces the physical reference plate, maximizing the oxygen signal through mathematical separation. This ensures high detection accuracy, improves detection efficiency, and reduces material costs. The use of the virtual reference plate is also compatible with existing FTIR equipment, eliminating the need for hardware modification.

[0057] Furthermore, the refitting of the infrared absorption spectrum curve in step S3 includes the following steps:

[0058] S3-1: Select a fitting segment on the infrared absorption spectrum curve, where the fitting segment includes the waveband.

[0059] like Figure 2 As shown, the two endpoints of the fitting segment are point D and point E. The fitting segment is the reconstructed object. The infrared absorption spectrum curve does not need to be re-fitted except for the fitting segment, and the original curve is retained.

[0060] Select multiple feature anchor points on the fitting segment, at least two feature anchor points are the two endpoints of the fitting segment ( Figure 2 Point D and point E in ), and at least two of the characteristic anchor points are the two endpoints of the band ( Figure 2 The remaining characteristic anchor points are located outside the band. The selection of these characteristic anchor points avoids the oxygen absorption peak in the curve, eliminating it from the fitted curve and, consequently, the influence of the oxygen content in the physical reference film. Furthermore, selecting the fitted segment for reconstruction allows for targeted reconstruction of local locations in the original infrared absorption spectrum curve. This not only eliminates the influence of the absorption peak, but also preserves the data in other sections of the original infrared absorption spectrum curve, ensuring overall data authenticity.

[0061] like Figure 2 As shown, the red points are all characteristic anchor points, point B and point C are the two endpoints of the band, and the remaining characteristic anchor points are located in the coordinate direction of the band along the wavelength ( Figure 2Points D and E are the endpoints of the fitting segment. This point selection method ensures that characteristic anchor points are evenly selected on the infrared absorption spectrum curve, so that the refitted curve can eliminate absorption peaks while ensuring a high degree of fit.

[0062] S3-2: Reconstruct the infrared absorption spectrum curve based on discrete points. For example, the infrared absorption spectrum curve can be reconstructed based on the B-Spline method. In addition, the discrete point reconstruction can also be done by other known algorithms, such as the least squares method, etc.

[0063] S3-3: Set a goodness-of-fit threshold. If the goodness-of-fit of the reconstructed infrared absorption spectrum curve is less than the goodness-of-fit threshold, execute step S3-1. When re-executing step S3-1, the goodness of fit can be improved by changing the position and / or number of feature anchor points, for example, by increasing the number of feature anchor points.

[0064] In this embodiment, for example, the goodness-of-fit threshold is set to 0.9. When the goodness-of-fit R of the reconstructed infrared absorption spectrum curve is greater than or equal to 0.9, the reconstruction requirement is met and the reconstructed infrared absorption spectrum curve is used as the curve of the virtual reference slice. If the goodness-of-fit R is less than 0.9, it is necessary to optimize the location and / or number of anchor points and reconstruct the curve to adjust the goodness-of-fit.

[0065] Furthermore, the virtual reference slice generation method further includes step S4;

[0066] S4: The fitted infrared absorption spectrum curve is stored in the database and associated with the device number.

[0067] The fitted infrared absorption spectrum curve corresponds to a virtual reference plate, and each virtual reference plate is associated with a device number. Multiple virtual reference plates can be stored in the database to accommodate different specifications, usage scenarios, and measurement requirements, allowing for subsequent testing and recall.

[0068] Furthermore, step S2 includes the following steps:

[0069] Obtain an absorption peak in an infrared absorption spectrum curve, set a step length, and extend at least one step length from the absorption peak to both sides of the coordinate direction of the wavelength on the infrared absorption spectrum curve to obtain the two end points of the band.

[0070] Combine Figure 2 As shown, for example, the absorption peak (point A) corresponds to a horizontal coordinate wave number of 1100, and the step size can be determined to be 50. Then, at the absorption peak, move one step to the left along the horizontal coordinate to a wave number of 1050, and move one step to the right to a wave number of 1150. Therefore, the curve segment corresponding to the horizontal coordinate of 1050 to 1150 is taken as the band corresponding to the absorption peak.

[0071] Alternatively, you can use the step size to determine the fitting segment. Along the wavelength coordinate, the step size between the end points of the fitting segment and the absorption peak should be larger than the step size between the end points of the wavenumber and the absorption peak. For example, at the absorption peak, take two steps to the left along the abscissa to wavenumber 1000 and four steps to the right to wavenumber 1300. Therefore, the curve segment corresponding to abscissas 1000 to 1300 is used as the reconstructed fitting segment.

[0072] Furthermore, before step S2, the infrared absorption spectrum curve is smoothed. For example, the infrared absorption spectrum curve is smoothed using a mathematical model such as adjacent-averaging or Savizky-Golay to eliminate random fluctuations or noise in the data, making the curve more consistent with the actual trend and facilitating subsequent baseline reconstruction.

[0073] This embodiment also provides an oxygen concentration measurement method, including the following steps:

[0074] S1: Measure the infrared absorption spectrum curve of the test piece by Fourier transform spectroscopy;

[0075] S2: The infrared absorption spectrum curve of the test piece is subtracted from the infrared absorption spectrum curve of the virtual reference piece to obtain the final infrared absorption spectrum curve; Figure 3 As shown in the coordinate direction corresponding to the absorbance (ordinate), the infrared absorption spectrum curve of the virtual reference piece (red curve) is subtracted from the infrared absorption spectrum curve of the test piece (black curve) to obtain the final infrared absorption spectrum curve (orange curve). At this time, the final infrared absorption spectrum curve eliminates the influence of impurities in the physical reference piece.

[0076] S3: Calculate the oxygen concentration of the test piece based on the final infrared absorption spectrum curve. This calculation method belongs to the existing technology and will not be repeated here.

[0077] This embodiment further provides a readable storage medium having a program stored thereon. When the program is executed, the virtual reference slice generation method is executed.

[0078] The readable storage medium can adopt any combination of one or more computer-readable media. The readable medium can be a computer-readable signal medium or a computer-readable storage medium. The computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared or semiconductor system, device or component, or any combination thereof. A non-exhaustive list of more specific examples of computer-readable storage media includes: an electrical connection with one or more wires, a portable computer hard disk, a hard disk, a random access memory RAM, a read-only memory ROM, an erasable programmable read-only memory EPROM or flash memory, an optical fiber, a portable compact disk read-only memory CD-ROM, an optical storage device, a magnetic storage device, or any suitable combination thereof. In this article, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by an instruction execution system, device or device or used in combination with it.

[0079] A computer-readable signal medium may include a data signal propagated in baseband or as part of a carrier wave, which carries computer-readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A computer-readable signal medium may also be any computer-readable medium other than a computer-readable storage medium that can transmit, propagate, or transport a program for use by or in conjunction with an instruction execution system, apparatus, or device.

[0080] The above description is only a description of the preferred embodiments of the present invention and is not intended to limit the scope of the present invention. Any changes and modifications made by ordinary technicians in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.

Claims

1. A method for generating a virtual reference slice, characterized in that: The following steps are involved: S1: Measure the infrared absorption spectrum of the physical reference film by Fourier transform spectroscopy; S2: Select the wavelength band corresponding to the absorption peak in the infrared absorption spectrum curve; S3: refitting the infrared absorption spectrum curve so that the peak value of the fitted infrared absorption spectrum curve corresponding to the wavelength band position is smaller than the absorption peak, and using the fitted infrared absorption spectrum curve as the infrared absorption spectrum curve of the virtual reference film.

2. The method for generating a virtual reference slice according to claim 1, wherein: Refitting the infrared absorption spectrum curve in step S3 includes the following steps: S3-1: selecting a plurality of characteristic anchor points on the infrared absorption spectrum curve, wherein at least two of the characteristic anchor points are two end points of the band, and the remaining characteristic anchor points are located outside the band; S3-2: Reconstruct the infrared absorption spectrum curve based on discrete points.

3. The method for generating a virtual reference slice according to claim 2, wherein: In step S3-1, the remaining characteristic anchor points are arranged on both sides of the wavelength band along the coordinate direction of the wavelength.

4. The method for generating a virtual reference slice according to claim 2, wherein: The refitting of the infrared absorption spectrum curve in step S3 further includes the following steps: S3-3: Set a goodness-of-fit threshold. If the goodness of fit of the reconstructed infrared absorption spectrum curve is less than the goodness-of-fit threshold, execute step S3-1.

5. The method for generating a virtual reference slice according to claim 2, wherein: Selecting multiple characteristic anchor points on the infrared absorption spectrum curve in step S3-1 includes the following steps: A fitting segment is selected on the infrared absorption spectrum curve, where the fitting segment includes the waveband, and a plurality of characteristic anchor points are selected on the fitting segment, where at least two characteristic anchor points are two endpoints of the fitting segment.

6. The method for generating a virtual reference slice according to claim 4, wherein: In step S3-3, if the goodness of fit is less than the goodness of fit threshold, step S3-1 is re-executed, and the position of the feature anchor points and / or the number of the feature anchor points are changed.

7. The method for generating a virtual reference slice according to claim 1, wherein: The virtual reference slice generation method further includes step S4; S4: The fitted infrared absorption spectrum curve is stored in the database and associated with the device number.

8. The method for generating a virtual reference slice according to claim 1, wherein: Before step S2, the following steps are also included: Smoothing of infrared absorption spectrum curve.

9. A method for measuring oxygen concentration, characterized in that: The following steps are involved: S1: Measure the infrared absorption spectrum curve of the test piece by Fourier transform spectroscopy; S2: subtracting the infrared absorption spectrum curve of the virtual reference film from the infrared absorption spectrum curve of the film to be tested to obtain a final infrared absorption spectrum curve, wherein the infrared absorption spectrum curve of the virtual reference film is obtained by the virtual reference film generation method according to any one of claims 1 to 8; S3: Calculate the oxygen concentration of the test piece based on the final infrared absorption spectrum curve.

10. A readable storage medium having a program stored thereon, characterized in that: When the program is executed, the virtual reference slice generating method is performed.

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