Method for measuring content distribution of impurity elements in gradient depth of surface layer of quartz glass product

Abstract

The invention relates to the technical field of material detection, and particularly discloses a method for determining content distribution of impurity elements in gradient depth of a surface layer of a quartz glass product. The method comprises the following steps: (1) putting a sample into a corrosion-resistant container in a clean environment; (2) adding 5-20wt% of hydrofluoric acid solution for etching, and collecting an extraction solution; (3) evaporating a part of the extraction solution to dryness, and adding 1-3wt% of nitric acid to dissolve residues; (4) measuring the concentration of impurity elements; (5) diluting the leaching solution, and then measuring the concentration of the silicon element; (6) performing a blank experiment; (7) calculating the etching quality and depth according to a formula; and (8) calculating the content of impurity elements in combination with the etching quality. According to the method, layer-by-layer analysis of the surface layer of the quartz glass at different depths in a range from submicron to tens of microns is realized, and the enrichment layer or diffusion gradient of impurity elements can be clearly and intuitively revealed.

Description

Technical Field

[0001] This invention relates to the field of materials testing technology, and more specifically, to a method for determining the distribution of impurity element content within the gradient depth of the surface layer of quartz glass products. This method is applicable to the surface quality testing of high-purity quartz glass products (such as diffusion furnace tubes, quartz boats, bell jars, etc.) in the fields of semiconductors and photovoltaics. Background Technology

[0002] High-purity quartz glass, with its unique physicochemical properties such as high temperature resistance, excellent chemical stability, and low impurity content, has become a key basic material supporting the development of strategic emerging industries such as semiconductors and photovoltaics. Market demand remains strong, and its strategic importance continues to rise. In the semiconductor chip manufacturing process, core process components such as diffusion furnace tubes, quartz boats, and bell jars are all made of high-purity quartz glass, making it an indispensable consumable in the semiconductor industry.

[0003] Currently, advanced chip manufacturing processes place near-stringent demands on the surface quality and cleanliness of quartz glass products. Even trace amounts (ng / g level) of impurities or defects can significantly reduce chip yield. However, during the processing and manufacturing of quartz glass products (such as cutting, polishing, and cleaning), impurities are inevitably introduced, and these contaminants are concentrated at a certain depth below the surface. Therefore, accurately measuring the distribution of impurity element content at different depths below the surface is a core technical requirement for evaluating the cleaning effect and surface quality of quartz glass products, and a key basis for process optimization and semiconductor device failure analysis.

[0004] Currently, there are mature methods in the industry for detecting the overall impurity element content of quartz glass (such as direct digestion + ICP-OES method), but there are still significant technical bottlenecks in the quantitative detection of impurity element distribution within the surface gradient depth, and existing mainstream methods have obvious limitations: Secondary ion mass spectrometry (SIMS): Although it has the ability to perform in-depth analysis and has high depth resolution, the equipment purchase and maintenance costs are high, the cost of analyzing a single sample is high, and the professional requirements of the operators are extremely high. At the same time, it faces serious quantitative calibration problems. The ion beam can also disturb the true distribution of easily migrating elements such as Na during the analysis process, which makes it difficult to popularize in industrial quality control. Glow discharge mass spectrometry (GD-MS): It is mainly suitable for bulk phase analysis, but its sensitivity and accuracy for depth resolution of surface micro-regions are insufficient, and it cannot accurately capture the gradient distribution of impurity elements. Total internal reflection X-ray fluorescence (TXRF): The detection depth is extremely shallow, limited to only a few nanometers of the outermost layer. It cannot achieve complete analysis from the shallow surface to a depth of tens of micrometers, and it is difficult to cover the main distribution area of ​​impurities on the surface of quartz glass.

[0005] Therefore, there is an urgent need in this field for a simple, cost-effective, and reliable method for detecting impurity elements at the gradient depth of the quartz glass surface, in order to fill the gap in existing technology and meet the quality control needs of industrial production. Summary of the Invention

[0006] The main objective of this invention is to propose a determination method based on "chemical etching-dual-spectral detection-quantitative calculation" to achieve low-cost, high-precision, and wide-depth-range characterization of impurity element distribution.

[0007] To address the aforementioned technical problems, this invention proposes a method for determining the distribution of impurity element content within the gradient depth of the surface layer of quartz glass products, comprising the following steps: (1) Sample preparation: Place the sample in a corrosion-resistant container in a clean environment; (2) Surface etching: Add a volume of [volume value missing] to the corrosion-resistant container. A 5-20 wt% hydrofluoric acid solution is used for etching for a set time, and then the extraction solution is collected. (3) Pretreatment of the extraction solution: Take a volume of The extraction solution was placed in a corrosion-resistant and high-temperature resistant beaker, evaporated to dryness at high temperature, and then cooled to room temperature; a volume of [unclear] was added to the beaker. A 1-3 wt% nitric acid solution is used to fully dissolve the evaporation residue; (4) Detection of impurity elements: Transfer the solution in the beaker to a clean container to obtain the solution to be tested for impurity elements, and determine the concentration of the target impurity element in the solution to be tested using an instrument; (5) Silicon element detection: Take a portion of the extraction solution, dilute it with ultrapure water by f times, and then determine the concentration of silicon element in the diluted solution using an instrument; (6) Blank experiment: Prepare blank samples without samples according to the operation of steps (1)-(5), and measure the concentration of silicon and the concentration of target impurity elements in the blank solution respectively; (7) Calculation of etching quality and depth: Based on the silicon concentration measured in steps (5) and (6), the etching quality of the quartz glass surface is calculated according to formula (1). Then calculate the etching depth according to formula (2). ; (8) Calculation of impurity element content: Based on the impurity element concentrations measured in steps (4) and (6), combined with the etching quality obtained in step (7) The content of the target impurity element at this depth is calculated according to formula (3). .

[0008] Wherein, formula (1): Formula (2): Formula (3): In formula (1-3): The etching mass of the quartz glass surface is expressed in grams. The concentration of silicon in the ICP-OES test solution is expressed in mg / L. The concentration of silicon in the ICP-OES blank solution is expressed in g / mol. This refers to the dilution factor; The volume is the total volume of the extraction solution, in mL. The value represents the relative molecular mass of silicon dioxide, expressed in g / mol. The value represents the relative atomic mass of silicon, expressed in g / mol. The etching depth on the surface of the quartz glass is expressed in μm. This is the density of quartz glass, expressed in g / cm³. The surface area of ​​quartz glass products is expressed in cm². The concentration of metallic element impurities in the surface layer of the quartz glass sample is expressed in ng / g. The volume concentration of each metal element in the solution to be tested by ICP-MS is given in μg / L. The volume concentration of each metal element in the ICP-MS blank solution is expressed in μg / L. The volume of the extraction solution to be evaporated to dryness is expressed in mL. The volume of the solution to be tested by ICP-MS is in mL.

[0009] Furthermore, the above technical solution also includes: (9) Gradient depth determination: Wash the quartz glass sample with ultrapure water, repeat steps (2)-(8) multiple times, obtain the impurity element content at different depth levels, and plot the impurity element content-depth distribution curve.

[0010] In any of the above technical solutions, further, in step (2), the etching time is 5-20 min.

[0011] In any of the above technical solutions, further, in step (3), the corrosion-resistant and high-temperature resistant beaker is a polytetrafluoroethylene beaker.

[0012] In any of the above technical solutions, further, in steps (4) and / or (6), the instrument is one of the following devices capable of testing the element content in aqueous solution: ICP-OES, ICP-MS, GFAAS, ICP-TOF-MS, etc.

[0013] In any of the above technical solutions, further, in step (4), the instrument is an ICP-MS.

[0014] In any of the above technical solutions, further, in step (6), the instrument is an ICP-OES.

[0015] In any of the above technical solutions, further, in step (4), the target impurity element includes, but is not limited to, one or more of Na, Mg, Al, K, Ca, Fe, and Cu.

[0016] In any of the above technical solutions, further, in step (9), the cumulative etching depth ranges from 0.2μm to 20μm.

[0017] Beneficial effects: Compared with existing technologies, This method uses ICP-OES to detect silicon content and calculates etching quality and depth in reverse, avoiding systematic errors caused by etching rate fluctuations and differences in sample surface roughness. It is more accurate and reliable than simply relying on theoretical etching rate to calculate depth. At the same time, the silicon substrate and trace impurities are detected separately (ICP-OES for silicon and ICP-MS for impurities), which effectively avoids the suppression and interference of the silicon substrate on the ICP-MS detection signal. The detection limit of impurity elements can reach the ng / g level, which is far superior to the detection accuracy of GD-MS.

[0018] This method enables layer-by-layer analysis of the surface of quartz glass at different depths ranging from submicron to tens of micron, and can clearly and intuitively reveal the enrichment layer or diffusion gradient of impurity elements. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a curve showing the content-depth distribution of impurity elements on the surface of quartz glass, as measured in Example 1 of this invention. Figure 2 This is a curve showing the content-depth distribution of impurity elements on the surface of quartz glass, as measured in Example 2 of this invention. Figure 3 This is a curve showing the content-depth distribution of impurity elements on the surface of quartz glass, as measured in Example 3 of this invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0022] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0023] To make the above-mentioned objectives, features and advantages of this aspect more apparent and understandable, specific embodiments of this aspect are described in detail below.

[0024] A method for determining the distribution of impurity element content within a gradient depth on the surface of a quartz glass product, characterized by comprising the following steps: (1) Sample preparation: Place the sample in a corrosion-resistant container in a clean environment; (2) Surface etching: Add a volume of [volume value missing] to the corrosion-resistant container. A 5-20 wt% hydrofluoric acid solution is used for etching for a set time, and then the extraction solution is collected. (3) Pretreatment of the extraction solution: Take a volume of The extraction solution was placed in a corrosion-resistant and high-temperature resistant beaker, evaporated to dryness at high temperature, and then cooled to room temperature; a volume of [unclear] was added to the beaker. A 1-3 wt% nitric acid solution is used to fully dissolve the evaporation residue; (4) Detection of impurity elements: Transfer the solution in the beaker to a clean container to obtain the solution to be tested for impurity elements, and determine the concentration of the target impurity element in the solution to be tested using an instrument; (5) Silicon element detection: Take a portion of the extraction solution, dilute it with ultrapure water by f times, and then determine the concentration of silicon element in the diluted solution using an instrument; (6) Blank experiment: Prepare blank samples without samples according to the operation of steps (1)-(5), and measure the concentration of silicon and the concentration of target impurity elements in the blank solution respectively; (7) Calculation of etching quality and depth: Based on the silicon concentration measured in steps (5) and (6), the etching quality of the quartz glass surface is calculated according to formula (1). Then calculate the etching depth according to formula (2). ; (8) Calculation of impurity element content: Based on the impurity element concentrations measured in steps (4) and (6), combined with the etching quality obtained in step (7) The content of the target impurity element at this depth is calculated according to formula (3). .

[0025] (9) Gradient depth determination: Wash the quartz glass sample with ultrapure water, repeat steps (2)-(8) multiple times, obtain the impurity element content at different depth levels, and plot the impurity element content-depth distribution curve.

[0026] Wherein, formula (1): Formula (2): Formula (3): In formula (1-3): The etching mass of the quartz glass surface is expressed in grams. The concentration of silicon in the ICP-OES test solution is expressed in mg / L. The concentration of silicon in the ICP-OES blank solution is expressed in g / mol. This refers to the dilution factor; The volume is the total volume of the extraction solution, in mL. The value represents the relative molecular mass of silicon dioxide, expressed in g / mol. The value represents the relative atomic mass of silicon, expressed in g / mol. The etching depth on the surface of the quartz glass is expressed in μm. This is the density of quartz glass, expressed in g / cm³. The surface area of ​​quartz glass products is expressed in cm². The concentration of metallic element impurities in the surface layer of the quartz glass sample is expressed in ng / g. The volume concentration of each metal element in the solution to be tested by ICP-MS is given in μg / L. The volume concentration of each metal element in the ICP-MS blank solution is expressed in μg / L. The volume of the extraction solution to be evaporated to dryness is expressed in mL. The volume of the solution to be tested by ICP-MS is in mL.

[0027] Furthermore, the above technical solution also includes: In step (2), the etching time is 5-20 min.

[0028] In step (3), the corrosion-resistant and high-temperature resistant beaker is a polytetrafluoroethylene beaker.

[0029] In steps (4) and / or (6), the instrument is one of the following devices capable of testing the elemental content in aqueous solution: ICP-OES, ICP-MS, GFAAS, ICP-TOF-MS, etc. Preferably, in step (4), the instrument is ICP-MS; and in step (6), the instrument is ICP-OES.

[0030] In step (4), the target impurity element includes, but is not limited to, one or more of Na, Mg, Al, K, Ca, Fe, and Cu.

[0031] To make the above-mentioned objectives, features and advantages of this method more apparent and understandable, the following examples and comparative examples will be used to describe in detail the method for manufacturing a high-temperature resistant coating on a quartz glass surface with high infrared reflectivity.

[0032] Example 1: This embodiment describes the process and effect of using low-concentration hydrofluoric acid etching to determine the distribution of impurity elements in the shallow layer (0.23μm-1.15μm), which is suitable for evaluating the surface cleaning effect of quartz glass products.

[0033] The process is as follows: (1) Sample preparation: Select a quartz glass boat for semiconductor diffusion process, cut it into 50mm×50mm×3mm test pieces (number B1), clean it with ultrapure water by ultrasonic cleaning and then dry it; open the packaging in a Class 100 clean room and put it into a pre-cleaned container.

[0034] (2) Surface etching: Add 20 mL of 5 wt% dilute hydrofluoric acid solution to the container and etch for 5 min. Keep the container still during the etching process to avoid disturbing the solution and affecting the etching uniformity. After etching, collect the extraction solution completely into a clean reagent bottle.

[0035] (3) Pretreatment of extraction solution: Take 5 mL of extraction solution and place it in a polytetrafluoroethylene beaker. Evaporate to dryness at high temperature on a heating platform. After cooling to room temperature, add 15 mL of 1 wt% nitric acid solution to completely dissolve the evaporation residue.

[0036] (4) Detection of impurity elements: The dissolved solution is transferred to a clean bottle and the concentration of impurity elements such as Na, Mg, Al, K, Ca, Fe, and Cu is determined by ICP-MS.

[0037] (5) Silicon element detection: Take 1 mL of the extraction solution into a clean bottle, then add 19 mL of ultrapure water to dilute it, shake well, and then use ICP-OES to detect the concentration of silicon element in the diluted solution.

[0038] (6) Blank experiment: Perform a blank experiment without samples according to the steps (1)-(5), that is, use only 20mL 5wt% hydrofluoric acid, 5mL extraction solution (blank), 15mL 1wt% nitric acid and other reagents, without adding quartz glass test pieces, and measure the concentration of silicon and each impurity element in the blank solution.

[0039] (7) Calculation: Substitute the silicon concentration detected by ICP-OES into formula (1) to calculate the etching mass m; combined with the density of quartz glass (2.2 g / cm³), the etching mass m is calculated. 3 ) and sample surface area (25cm²) 2 The etching depth D is calculated using formula (2); then the concentration of impurity elements detected by ICP-MS is substituted into formula (3) to calculate the content of each impurity element at that depth.

[0040] (8) Gradient depth measurement: The etched sample was ultrasonically cleaned with ultrapure water and dried to remove residual acid and impurities on the surface. The above steps (2)-(7) were repeated 4 times to obtain detection data for 5 depth levels.

[0041] Test results and effects: The impurity element content at each depth level is shown in the table below. Figure 1 As shown: Performance Analysis: This embodiment achieved gradient depth detection of the shallow surface layer from 0.23μm to 1.15μm using 5wt% low-concentration dilute hydrofluoric acid etching, with a depth resolution of 0.01μm. The detection results showed that impurities such as Na, Mg, K, Ca, and Fe had the highest content in the outermost layer (0.23μm), decreasing rapidly with increasing depth and then stabilizing, consistent with the contamination pattern of "surface adsorption impurities" during quartz glass processing. Specifically, the Na content in the outermost layer reached 175.9 ng / g, decreasing to 15.5 ng / g at a depth of 0.93μm after cleaning. This indicates that the cleaning process effectively removes shallow surface impurities, and these results provide a precise basis for optimizing cleaning time and reagent concentration.

[0042] Example 2: This embodiment describes the process and effect of using medium-concentration hydrofluoric acid etching to determine the distribution of impurity element content in the middle layer depth (0.59μm-3.03μm), which is suitable for analyzing the diffusion gradient of impurity elements.

[0043] The process is as follows: (1) Sample preparation: Select a quartz glass boat sample (number B2) of the same specifications as in Example 1, clean and dry it, and place it in a clean container in a Class 100 clean room.

[0044] (2) Surface etching: Add 20 mL of 10 wt% dilute hydrofluoric acid solution to the container, etch for 10 min, and collect the extract solution.

[0045] (3) Pretreatment of extraction solution: Take 5 mL of extraction solution and place it in a polytetrafluoroethylene beaker. Evaporate to dryness at high temperature. After cooling, add 15 mL of 2 wt% nitric acid solution to fully dissolve the residue.

[0046] (4) Detection of impurity elements: The concentrations of impurity elements such as Na, Mg, Al, K, Ca, Fe, and Cu were determined by ICP-MS.

[0047] (5) Silicon element detection: Take 1 mL of the extraction solution, dilute it 20 times with ultrapure water, and then detect the silicon element concentration by ICP-OES.

[0048] (6) Blank experiment: Perform the blank experiment according to the same steps to obtain blank concentration data.

[0049] (7) Calculation: The etching depth and impurity element content are calculated using formulas (1), (2) and (3).

[0050] (8) Gradient depth measurement: After cleaning the sample, repeat the above steps 4 times to obtain detection data of 5 depth levels.

[0051] Test results and effects: The impurity element content at each depth level is shown in the table below. Figure 2 As shown: Results Analysis: This embodiment achieved gradient detection at a mid-layer depth of 0.59μm-3.03μm through etching with 10wt% medium-concentration dilute hydrofluoric acid. This depth range covers the diffusion area of ​​surface impurities in quartz glass. The results show that Al content is highest within this depth range and decreases slowly with increasing depth (from 4544.2 ng / g to 2456.7 ng / g), possibly related to trace Al impurities in the quartz glass raw material or high-temperature diffusion during processing. The contents of other impurity elements (such as Na, K, and Ca) gradually stabilize with increasing depth, indicating that these impurities are mainly concentrated within the surface layer of 1.8μm. These detection results can provide key data for process improvement, such as optimizing temperature control parameters during processing to reduce the diffusion depth of impurities, particularly regarding Al diffusion. They can also provide a basis for product quality grading, such as requiring an Al content of less than 3000 ng / g at a mid-layer depth (2μm) as a standard for high-end products.

[0052] Example 3: This embodiment describes the process and effect of using high-concentration hydrofluoric acid etching to determine the distribution of impurity elements in the deeper surface layer (4.11μm-20.34μm), which is suitable for evaluating the deep cleanliness of quartz glass products.

[0053] The process is as follows: (1) Sample preparation: Select a quartz glass boat sample (number B3) of the same specifications as in Example 1, clean and dry it, and place it in a clean container in a Class 100 clean room.

[0054] (2) Surface etching: Add 20 mL of 20 wt% dilute hydrofluoric acid solution to the container, etch for 20 min, and collect the extract solution.

[0055] (3) Pretreatment of extraction solution: Take 5 mL of extraction solution and place it in a polytetrafluoroethylene beaker and evaporate it to dryness at high temperature; after cooling, add 15 mL of 3 wt% dilute nitric acid solution to fully dissolve the residue.

[0056] (4) Detection of impurity elements: The concentrations of impurity elements such as Na, Mg, Al, K, Ca, Fe, and Cu were determined by ICP-MS.

[0057] (5) Silicon element detection: Take 1 mL of the extraction solution, dilute it 20 times with ultrapure water, and then detect the silicon element concentration by ICP-OES.

[0058] (6) Blank experiment: Perform the blank experiment according to the same steps to obtain blank concentration data.

[0059] (7) Calculation: The etching depth and impurity element content are calculated using formulas (1), (2) and (3).

[0060] (8) Gradient depth measurement: After cleaning the sample, repeat the above steps 4 times to obtain detection data of 5 depth levels.

[0061] Test results and effects: The impurity element content at each depth level is shown in the table below. Figure 3 As shown: Results Analysis: This embodiment achieved gradient detection of a relatively deep surface layer from 4.11μm to 20.34μm through etching with 20wt% high-concentration dilute hydrofluoric acid, covering the main distribution area of ​​surface impurities in quartz glass. The results showed that a relatively high content of impurity elements (such as Na: 323.6 ng / g, Al: 12161.3 ng / g) still existed at a depth of 4.11μm, gradually stabilizing with increasing depth, indicating that some impurities had diffused to a deeper surface layer during processing. The content of Al element remained high throughout the entire detection depth range, and it may be an intrinsic impurity of quartz glass. Its stable concentration (approximately 7000 ng / g) can be used as a characteristic indicator of this batch of quartz glass raw materials. These detection results can provide a basis for quality screening of high-requirement quartz glass products. For example, quartz boats used in high-end chip manufacturing require an Al element content of less than 7500 ng / g and a Na element content of less than 20 ng / g at a depth of 20μm. This method can quickly screen out qualified products.

[0062] The various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for determining the distribution of impurity element content within a gradient depth of the surface layer of a quartz glass product, characterized in that, Includes the following steps: (1) Sample preparation: Place the sample in a corrosion-resistant container in a clean environment; (2) Surface etching: Add a volume of [volume value missing] to the corrosion-resistant container. A 5-20 wt% hydrofluoric acid solution is used for etching for a set time, and then the extraction solution is collected. (3) Pretreatment of the extraction solution: Take a volume of The extraction solution was placed in a corrosion-resistant and high-temperature resistant beaker, evaporated to dryness at high temperature, and then cooled to room temperature; a volume of [unclear] was added to the beaker. A 1-3 wt% nitric acid solution is used to fully dissolve the evaporation residue; (4) Detection of impurity elements: Transfer the solution in the beaker to a clean container to obtain the solution to be tested for impurity elements, and determine the concentration of the target impurity element in the solution to be tested using an instrument; (5) Silicon element detection: Take a portion of the extraction solution, dilute it with ultrapure water by f times, and then determine the concentration of silicon element in the diluted solution using an instrument; (6) Blank experiment: Prepare blank samples without samples according to the operation of steps (1)-(5), and measure the concentration of silicon and the concentration of target impurity elements in the blank solution respectively; (7) Calculation of etching quality and depth: Based on the silicon concentration measured in steps (5) and (6), the etching quality of the quartz glass surface is calculated according to formula (1). Then calculate the etching depth according to formula (2). ; (8) Calculation of impurity element content: Based on the impurity element concentrations measured in steps (4) and (6), combined with the etching quality obtained in step (7) The content of the target impurity element at this depth is calculated according to formula (3). ; Wherein, formula (1): Formula (2): Formula (3): In formula (1-3): The etching mass of the quartz glass surface is expressed in grams. The concentration of silicon in the ICP-OES test solution is expressed in mg / L. The concentration of silicon in the ICP-OES blank solution is expressed in g / mol. This refers to the dilution factor; The volume is the total volume of the extraction solution, in mL. The value represents the relative molecular mass of silicon dioxide, expressed in g / mol. The value represents the relative atomic mass of silicon, expressed in g / mol. The etching depth on the surface of the quartz glass is expressed in μm. This is the density of quartz glass, expressed in g / cm³. The surface area of ​​quartz glass products is expressed in cm². The concentration of metallic element impurities in the surface layer of the quartz glass sample is expressed in ng / g. The volume concentration of each metal element in the solution to be tested by ICP-MS is given in μg / L. The volume concentration of each metal element in the ICP-MS blank solution is expressed in μg / L. The volume of the extraction solution to be evaporated to dryness is expressed in mL. The volume of the solution to be tested by ICP-MS is in mL.

2. The method for determining the distribution of impurity element content within the gradient depth of the surface layer of a quartz glass product as described in claim 1, characterized in that, Also includes: (9) Gradient depth determination: Wash the quartz glass sample with ultrapure water, repeat steps (2)-(8) multiple times, obtain the impurity element content at different depth levels, and plot the impurity element content-depth distribution curve.

3. The method for determining the distribution of impurity element content within the gradient depth of the surface layer of a quartz glass product as described in claim 1, characterized in that, In step (2), the etching time is 5-20 min.

4. The method for determining the distribution of impurity element content within the gradient depth of the surface layer of a quartz glass product as described in claim 1, characterized in that, In step (3), the corrosion-resistant and high-temperature resistant beaker is a polytetrafluoroethylene beaker.

5. The method for determining the distribution of impurity element content within the gradient depth of the surface layer of a quartz glass product as described in claim 1, characterized in that, In steps (4) and / or (6), the instrument is one of the following devices capable of testing the element content in aqueous solution: ICP-OES, ICP-MS, GFAAS, ICP-TOF-MS, etc.

6. The method for determining the distribution of impurity element content within the gradient depth of the surface layer of a quartz glass product as described in claim 5, characterized in that, In step (4), the instrument is ICP-MS.

7. The method for determining the distribution of impurity element content within the gradient depth of the surface layer of a quartz glass product as described in claim 5, characterized in that, In step (6), the instrument is an ICP-OES.

8. The method for determining the distribution of impurity element content within the gradient depth of the surface layer of a quartz glass product as described in claim 1, characterized in that, In step (4), the target impurity element includes, but is not limited to, one or more of Na, Mg, Al, K, Ca, Fe, and Cu.

9. The method for determining the distribution of impurity element content within the gradient depth of the surface layer of a quartz glass product as described in claim 2, characterized in that, In step (9), the cumulative etching depth ranges from 0.2 μm to 20 μm.

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