ICP analysis device and method

Abstract

The invention provides an ICP (Inductively Coupled Plasma) analysis device and method, the ICP analysis device comprises a light receiving unit, and the light receiving unit comprises a grating and a detector; the adjusting module is used for adjusting the angle of the grating relative to the measuring light; measuring light penetrating through the prism is subjected to primary diffraction on the grating; the first-stage diffracted light is reflected for multiple times among the first reflector, the grating and the second reflector and diffracted for multiple times on the grating, and the last-stage diffracted light passes through the prism; and the digital micromirror is used for reflecting the last level of diffraction light penetrating through the prism to the detector. The method has the advantages of high detection capability and the like.

Description

Technical Field

[0001] The present invention relates to spectral technology, in particular to an ICP analysis device and method. Background Art

[0002] Traditional ICP UV spectrometers have two optical system structures: 1. Back-to-back dual grating design, by using two independently rotating gratings, the dual grating spectrometer can image two far-apart bands in adjacent areas, thereby greatly expanding the spectral coverage. At the same time, the system can provide higher spectral resolution because it allows finer spectral separation. The shortcomings of this system are: More complex optical design and adjustments are required to ensure precise alignment and synchronization of the two gratings. Involving more optical components and a more complex design, a dual-grating spectrometer may be more expensive, larger and heavier.

[0003] 2. Rowland circle ultraviolet spectrometer, which can provide high spectral resolution, covers a wide wavelength range from vacuum ultraviolet to visible light, and has a compact physical structure and high sensitivity. However, its structure is complex, its size is large and requires regular maintenance. At the same time, its manufacturing process is difficult and it is greatly affected by the environment.

[0004] Currently, there is no ICP ultraviolet spectrometer on the market that is small in size, high in resolution, and easy to install and maintain. In addition, the characteristic spectra of ultraviolet elements in most spectrometers are severely interfered, resulting in a significant reduction in detection capabilities and failure to meet detection needs. Summary of the invention

[0005] In order to solve the deficiencies in the above-mentioned prior art solutions, the present invention provides an ICP analysis device.

[0006] The objective of the present invention is achieved through the following technical solutions: An ICP analysis device includes a light receiving unit, wherein the light receiving unit includes a grating and a detector; the analysis unit also includes: An adjustment module, the adjustment module is used to adjust the angle of the grating relative to the measurement light; A prism, wherein the measuring light passing through the prism undergoes first-order diffraction on the grating; A first reflector and a second reflector, the first-order diffracted light is reflected multiple times between the first reflector, the grating and the second reflector, and is diffracted multiple times on the grating, and the last-order diffracted light passes through the prism; A digital micromirror is used to reflect the last-order diffraction light passing through the prism to the detector.

[0007] The present invention also aims to provide an ICP analysis method, which is achieved by the following technical solutions: An ICP analysis method comprises the following steps: (A1) The measuring light passes through a prism and then undergoes first-order diffraction on the grating; (A2) the first-order diffracted light is reflected multiple times between the first reflector, the grating, and the second reflector, and is diffracted multiple times on the grating, and the last-order diffracted light passes through the prism; (A3) The digital micromirror selects and sets the wavelength so that the last order diffraction light passing through the prism is reflected by the digital micromirror to the detector.

[0008] Compared with the prior art, the present invention has the following beneficial effects: 1. Improved response intensity in the ultraviolet region: The adjustment module is used to adjust the grating incident angle, collect the spectrum of a specific area while taking into account the spectral line coverage range, make full use of the advantages of the mid-step ruled grating, perform multiple dispersions while taking into account the spectral response sensitivity, and improve the spectral resolution to the fm level; 2. Simple structure and small size: Adding drive modules and reflectors in reasonable areas will not interfere with the existing cavity, thus avoiding the shortcomings of Rowland circle spectrometers, such as large size and difficulty in maintenance; 3. Reduce spectral interference and improve UV performance: The digital micromirror reflection angle is set for each characteristic spectral line to minimize spectral interference and increase UV intensity. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The disclosure of the present invention will become easier to understand with reference to the accompanying drawings. It is easy for those skilled in the art to understand that these drawings are only used to illustrate the technical solution of the present invention and are not intended to limit the scope of protection of the present invention. In the drawings: Figure 1 is a simplified structural diagram of an ICP analysis device according to the present invention; Figure 2-3 is a spectrum diagram output according to the present invention. DETAILED DESCRIPTION

[0010] Figure 1-Figure 3The following description describes optional specific embodiments of the present invention to teach those skilled in the art how to implement and reproduce the present invention. In order to teach the technical solution of the present invention, some conventional aspects have been simplified or omitted. Those skilled in the art will understand that variations or replacements derived from these specific embodiments will be within the scope of the present invention. Those skilled in the art will understand that the following features can be combined in various ways to form multiple variations of the present invention. Thus, the present invention is not limited to the following optional specific embodiments, but is only limited by the claims and their equivalents.

[0011] Example 1.

[0012] An ICP analysis device according to an embodiment of the present invention includes a light receiving unit, such as Figure 1 As shown, the light receiving unit includes: The grating 22 and the ultraviolet detector 41 are the prior art in this field.

[0013] An adjustment module, such as a motor, is used to adjust the angle of the grating 22 relative to the measurement light; A prism 21, wherein the measuring light passing through the prism 21 undergoes first-order diffraction on the grating 22; The first reflector 15 and the second reflector 16, the first-order diffracted light is reflected multiple times between the first reflector 15, the grating 22 and the second reflector 16, and is diffracted multiple times on the grating 22, and the last-order diffracted light passes through the prism 21; The digital micromirror 31 is used for reflecting the last order diffraction light passing through the prism 21 to the ultraviolet detector 41 .

[0014] For better imaging, further, the light receiving unit further includes: The imaging mirror 14 is used to reflect and focus the last-order diffraction light passing through the prism 21 onto the digital micromirror 31 .

[0015] In order to prevent the influence of external stray light, further, the light receiving unit also includes: The slit 51 and the collimator 13 , the measuring light passes through the slit 51 , is collimated by the collimator 13 , and then is incident on the prism 21 .

[0016] In order to allow the measuring light to accurately pass through the slit 51, further, the light receiving unit further includes: A third reflecting mirror 11 and a fourth reflecting mirror 12, wherein the measuring light is reflected by the third reflecting mirror 11 and the fourth reflecting mirror 12 in sequence, and the reflected light passes through the slit 51; A driving module, wherein the driving module is used to adjust the angle of the fourth reflector 12 relative to the incident measurement light.

[0017] An ICP analysis method according to an embodiment of the present invention, that is, a working method of the analysis device according to this embodiment, comprises the following steps: (A1) The measuring light passes through the prism 21 and then undergoes first-order diffraction on the grating 22; (A2) The first-order diffracted light is reflected multiple times between the first reflector 15, the grating 22, and the second reflector 16, and is diffracted multiple times on the grating 22, and the last-order diffracted light passes through the prism 21; (A3) The digital micromirror 31 selects and sets a wavelength so that the last-order diffracted light passing through the prism 21 is reflected by the digital micromirror 31 to the detector 41 .

[0018] For better imaging, further, in step (A3), the last order diffraction light passing through the prism 21 is reflected by the imaging mirror 14 and focused on the digital micromirror 31 .

[0019] In order to eliminate the interference of external stray light, further, in step (A1), the measuring light passes through the slit 51 and is then collimated by the collimator 13 and incident on the prism 21 .

[0020] Example 2.

[0021] An application example of the ICP analysis device and method in Example 1 of the present invention.

[0022] In this application example, Figure 1 As shown, the third reflector 11 and the fourth reflector 12 are arranged in sequence, and the measuring light is reflected by the third reflector 11 and the fourth reflector 12 in sequence. The driving module adjusts the position of the fourth reflector 12 so that the reflected light on the fourth reflector 12 accurately passes through the slit 51 and enters the shell.

[0023] The measuring light passing through the slit 51 is reflected by the reflective collimator 13, and the collimated measuring light passes through the prism 21. The transmitted light is incident on the echelle grating 22, and first-order diffraction occurs. The first-order diffracted light is reflected by the first reflector 15, and the reflected light is incident on the grating 22, and second-order diffraction occurs. The second-order diffracted light is reflected by the second reflector 16, and the reflected light is incident on the grating 22, and third-order diffraction occurs. The third-order diffracted light is reflected by the first reflector 15, and the reflected light is incident on the grating 22, and fourth-order diffraction occurs. The fourth-order diffracted light passes through the prism 21 again.

[0024] The fourth-order diffraction light is reflected by the imaging mirror 14 and focused on the digital micromirror 31 . The reflected light passes through other reflection mirrors and is incident on the ultraviolet detector 41 .

[0025] An ICP analysis method according to an embodiment of the present invention, that is, a working method of the analysis device according to this embodiment, comprises the following steps: (A1) The measuring light is reflected by the third reflector 11 and the fourth reflector 12 in sequence, and the driving module adjusts the position of the fourth reflector 12 so that the reflected light on the fourth reflector 12 accurately passes through the slit 51 and enters the housing.

[0026] The measuring light passing through the slit 51 is reflected by the reflective collimator 13 , and the collimated measuring light passes through the prism 21 . The transmitted light is incident on the echelle grating 22 , and first-order diffraction occurs.

[0027] (A2) The first-order diffracted light is reflected by the first reflector 15, and the reflected light is incident on the grating 22, and the second-order diffraction occurs. The second-order diffracted light is reflected by the second reflector 16, and the reflected light is incident on the grating 22, and the third-order diffraction occurs. The third-order diffracted light is reflected by the first reflector 15, and the reflected light is incident on the grating 22, and the fourth-order diffraction occurs. The fourth-order diffracted light passes through the prism 21.

[0028] (A3) The fourth-order diffraction light is reflected by the imaging mirror 14 and focused on the digital micromirror 31. The reflected light passes through other mirrors and is incident on the ultraviolet detector 41, thereby obtaining a spectrum, such as Figure 2-3 shown.

[0029] The fourth-order diffraction light passing through the prism satisfies: ;

[0030] .

[0031] L xt is the meridian length, Δφ xt is the meridian deviation, L st is the length of the sagittal line, Δφ st is the sagittal deviation; f is the optical path of the light beam between the imaging mirror 14 and the digital micromirror 31, θ n is the diffraction angle, λ is the wavelength, n=1,2…M, M is a positive integer, d is the grating constant, and m is the diffraction order. Using the f in the proposed optical design, f and the fourth diffraction angle θ n The product of is the optical path in the diffraction direction, but due to the existence of astigmatism, there is an error in the focus of the meridian sagittal plane, so the actual optical path needs to increase the deviation in the direction in each direction.

[0032] S is the actual area of ​​the spectrum, Δφ s1 Represents the error caused by spherical aberration, Δφ s2 represents the error caused by the refraction of the surface of the digital micromirror 31, Δφ s3Represents the error caused by adjacent spectra. The line distances on the meridian and sagittal are used to calculate the image plane receiving spectrum area on each surface, the obtained spectrum area is averaged, and it is summed with the error contributed by spherical aberration, refraction, and adjacent spectra to the spectrum area to obtain the actual area of ​​the spectrum surface.

[0033] u f is the uncertainty, u x represents the error of the spectral integration area in the meridian direction, u y represents the error of the spectral integrated area in the sagittal direction, x represents the optical path difference of the selected wavelength in the meridional direction, and y represents the optical path difference of the selected wavelength in the sagittal direction.

[0034] In the experiment, there will be differences between the measurement results and the true value due to various factors (such as instrument accuracy, environmental conditions, etc.). Since the calculation of the spectral area needs to be close to the true value, uncertainty limiting conditions are introduced, and the optical path on the meridian and sagittal axes is partially derived. When the uncertainty u f When the above conditions are met, the current calculated area is considered valid.

[0035] In order to prevent stray light from entering the digital micromirror 31 and causing flipping and sampling of erroneous spectra, the following conditions must be met at the same time: , , Where N is the number of micromirrors that need to be reversed, Ω is the stereoscopic angle of the photosensitive surface receiver of the digital micromirror 31, and I max Indicates the coordinate position of the maximum value of the characteristic spectral line signal intensity received on the photosensitive surface, I min Indicates the coordinate position of the minimum value point of the characteristic spectrum line signal intensity received on the photosensitive surface. By using the product of the actual spectrum area and the receiver solid angle, the default receiving area side length is x, and the inversion quantity is obtained to correctly reflect the target spectrum line and filter out the non-target spectrum line.

[0036] Value is the set threshold, (I max -I min ) / 2 is the average value of the intensity difference, Res is the spectral resolution. When N≥Value, the irradiation dispersion spectrum is considered to be the effective spectrum.

[0037] , .

[0038] A is the detected beam energy, B is the modulation coefficient, φ H (m) and φ V (n) represents the phase in the horizontal and vertical directions, i represents the phase shift sequence, and M represents the maximum value of the sequence. i (m) and Vi (n) Spectral modulation images in the horizontal and vertical directions.

[0039] ; .

[0040] I i (x,y) represents the target spectral intensity, and The average intensity of the spectrum and the intensity after modulation, φ(x,y) represents the expected phase average, γ i Indicates the wavelength phase shift. The detected spectral intensity is subjected to intensity fitting and phase shift correction according to the above formula to obtain the target spectrum.

[0041] The parameters of this embodiment are as follows.

[0042] Initial calculation parameter values

[0043] Repeat experiment at 180nm resolution

[0044] Initial calculation parameter values

[0045] Repeat experiment at P177nm resolution

[0046] It can be seen from the above data that by using the above-mentioned restrictions to correct the errors of the spectrum in the meridian and sagittal planes, the final spectral spot area is close to the actual value to the greatest extent, while improving the spectral resolution and ensuring the accuracy of the resolution.

Claims

1. An ICP analysis device, comprising a light receiving unit, wherein the light receiving unit comprises a grating and a detector; characterized in that: The analysis unit also includes: An adjustment module, the adjustment module is used to adjust the angle of the grating relative to the measurement light; A prism, wherein the measuring light passing through the prism undergoes first-order diffraction on the grating; A first reflector and a second reflector, the first-order diffracted light is reflected multiple times between the first reflector, the grating and the second reflector, and is diffracted multiple times on the grating, and the last-order diffracted light passes through the prism; A digital micromirror is used to reflect the last-order diffraction light passing through the prism to the detector.

2. The ICP analysis device according to claim 1, characterized in that: The light receiving unit further includes: An imaging mirror is used to reflect and focus the last-order diffracted light passing through the prism onto the digital micromirror.

3. The ICP analysis device according to claim 1, characterized in that: The light receiving unit further includes: A slit and a collimator, the measuring light passes through the slit, is collimated by the collimator, and then is incident on the prism.

4. The ICP analysis device according to claim 1, characterized in that: The light receiving unit further includes: a third reflecting mirror and a fourth reflecting mirror, wherein the measuring light is reflected by the third reflecting mirror and the fourth reflecting mirror in sequence, and the reflected light passes through the slit; A driving module is used to adjust the angle of the fourth reflector relative to the incident measurement light.

5. The ICP analysis device according to claim 1, characterized in that: The grating is an echelle grating, and the detector is an ultraviolet detector.

6. An ICP analysis method comprising the following steps: (A1) The measuring light passes through a prism and then undergoes first-order diffraction on the grating; (A2) the first-order diffracted light is reflected multiple times between the first reflector, the grating, and the second reflector, and is diffracted multiple times on the grating, and the last-order diffracted light passes through the prism; (A3) The digital micromirror selects and sets the wavelength so that the last order diffraction light passing through the prism is reflected by the digital micromirror to the detector.

7. The ICP analysis method according to claim 6, characterized in that In step (A3), the last order diffraction light passing through the prism is reflected by the imaging mirror and focused on the digital micromirror.

8. The ICP analysis method according to claim 6, characterized in that In step (A1), the measuring light passes through the slit and is then collimated by the collimator lens and incident on the prism.

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