Method for detecting metal and other impurities in clean dust-free cloth

Abstract

The invention relates to the technical field of impurity detection, in particular to a method for detecting metal and other impurities in clean dust-free cloth, which comprises the following steps: weighing the initial mass M0 of a corrosion-resistant container, putting the dust-free cloth to be detected into the container, and measuring the total mass M1; soaking liquid is added into the container, so that the dust-free cloth is completely immersed; the container is placed on a heating device for constant-temperature heating treatment, metal and other impurity elements in the dust-free cloth are released into the soaking solution, the dust-free cloth is taken out after treatment is finished, and a solution to be detected is obtained; carrying out element content detection on the solution to be detected, and synchronously carrying out a blank experiment to respectively obtain detection results C1 and C0; and calculating the content of each element in the dust-free cloth according to the detection result, the volume of the soaking liquid and the mass difference value. According to the method, the accuracy and repeatability of a detection result can be improved, so that the content of each element in the dust-free cloth can be accurately measured.

Description

Technical Field

[0001] This invention relates to the field of impurity detection technology, specifically to a method for detecting metals and other impurities in cleanroom cloths. Background Technology

[0002] With the rapid development of the semiconductor manufacturing industry, the electronic information industry, and the high-end equipment manufacturing sector, the requirements for the cleanliness of production environments are increasing. Cleanroom wipes, as a key consumable, are widely used in processes such as wafer surface cleaning and precision component wiping. Their cleanliness directly affects product yield and device reliability. Current technologies primarily focus on evaluating the performance of cleanroom wipes in terms of particle release, electrostatic properties, and corrosion resistance, and corresponding testing standards and evaluation systems have been established. However, the detection of metal and other elemental impurities in cleanroom wipes remains relatively weak.

[0003] In existing technologies, the detection of trace elements in materials typically employs a combination of acid extraction and instrumental analysis. For example, samples are soaked in a single acid system or a simple mixed acid system, followed by inductively coupled plasma atomic emission spectrometry (ICP-AES) to determine the element content in the solution. However, when applied to cleanroom fabric materials, these methods often suffer from problems such as insufficient element release, large fluctuations in detection results, and difficulty in effectively eliminating background interference due to the complex fiber structure and impurity distribution. This affects the accuracy and stability of the detection results, making it difficult to meet the requirements for trace contaminant control in high-cleanliness applications. Summary of the Invention

[0004] The technical objective of this invention is to provide a method for detecting metals and other impurities in cleanroom wipes, so as to achieve efficient release and accurate quantification of trace metals and other elements in cleanroom wipes.

[0005] To achieve the above-mentioned technical objectives, the present invention provides the following technical solution: The present invention provides a method for detecting metals and other impurities in cleanroom wipes, comprising the following steps: Weigh the initial mass M0 of the corrosion-resistant container, place the cleanroom cloth to be tested into the container and measure the total mass M1; add soaking solution to the container to completely submerge the cleanroom cloth; The container is placed on a heating device for constant temperature heating treatment, so that the metal and other impurity elements in the cleanroom cloth are released into the soaking solution. After the treatment is completed, the cleanroom cloth is taken out to obtain the solution to be tested. The elemental content of the test solution was determined, and a blank test was performed simultaneously to obtain the test results C1 and C0, respectively. Based on the test results, the volume of the soaking solution, and the mass difference, the content of each element in the cleanroom cloth is calculated.

[0006] Preferably, the soaking solution is a mixed acid solution prepared by mixing hydrofluoric acid, nitric acid and ultrapure water.

[0007] More preferably, the volume ratio of each component in the soaking solution is hydrofluoric acid: nitric acid: ultrapure water = 3:5:92.

[0008] Based on the above, more preferably, the hydrofluoric acid has a mass fraction of 48.8%-49.2%, and the nitric acid has a mass fraction of 69%-71%.

[0009] Preferably, the heat treatment temperature is 50-70°C and the heating time is 5-15 minutes.

[0010] Preferably, the element content is determined using inductively coupled plasma atomic emission spectrometry.

[0011] Preferably, the corrosion-resistant container is a PFA beaker.

[0012] The content of each element in the cleanroom cloth is calculated based on the test results, the volume V of the soaking liquid, and the mass difference. The content of each element is calculated according to the following formula: W=(C1-C0)×V / (M1-M0), where W is the element content in the cleanroom cloth; M1-M0 is the mass difference; and V is the volume of the soaking liquid.

[0013] The beneficial effects of this invention are as follows: 1. This invention involves immersing the cleanroom cloth in an immersion solution and heating it under constant temperature conditions. This accelerates the release of metals and other impurities from the fiber matrix into the liquid phase. Simultaneously, background signals are subtracted using a blank experiment, and quantitative calculations are performed based on the detection results, the volume of the immersion solution, and the mass difference. This enables accurate determination of trace element content in the cleanroom cloth, significantly improving the accuracy and repeatability of the detection results.

[0014] 2. This invention uses a mixed acid soaking solution prepared by hydrofluoric acid, nitric acid and ultrapure water in a volume ratio of 3:5:92. The hydrofluoric acid is used to destroy the inorganic residual structure in the fiber, and the nitric acid provides an oxidizing environment to promote the dissolution of metal elements. This allows impurity elements in different states to effectively enter the solution, thereby improving the sufficiency of element release and reducing detection deviations caused by incomplete extraction.

[0015] 3. This invention also improves the efficiency of element release and avoids excessive matrix decomposition by controlling the heating conditions within a reasonable range. Combined with the low background characteristics of the corrosion-resistant beaker and the high sensitivity of inductively coupled plasma spectroscopy, it effectively reduces external contamination and detection errors, thereby improving the stability of the detection process and the reliability of the results. Attached Figure Description

[0016] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] The above and other aspects of the invention will now be described by way of example only, with reference to the accompanying drawings, in which: Figure 1 This is a flowchart of the detection method according to an embodiment of the present invention. Detailed Implementation

[0018] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods. Example

[0019] Cleanroom wipes were selected as the test sample. The initial mass M0 of a clean, corrosion-resistant container was weighed. The wipes were placed into the container using a clean fixture, and the total mass M1 was measured. Immersion solution was then added to the container to completely submerge the wipes. The container was placed on a heating device for constant-temperature heating, causing metals and other impurities in the wipes to be released from the fiber matrix into the immersion solution under heating conditions. After the treatment, the wipes were removed, yielding the test solution. The elemental content of the test solution was analyzed, and a blank experiment was performed simultaneously, yielding the results C1 and C0. The content of each element in the wipes was calculated based on the volume of the immersion solution and the mass difference (M1-M0).

[0020] Through the above processing, under the combined action of the soaking solution and heating, the original metal and other impurity elements in the cleanroom cloth are fully introduced into the liquid phase system. The background signal is corrected by blank experiments, and then the mass difference and volume parameters are combined for conversion, thereby realizing the quantitative determination of the element content in the cleanroom cloth and improving the accuracy and stability of the detection results. Example

[0021] Based on Example 1, in this further embodiment, the soaking solution is a mixed acid solution prepared by mixing hydrofluoric acid, nitric acid, and ultrapure water, wherein the mass fraction of hydrofluoric acid is 48.8%–49.2%, the mass fraction of nitric acid is 69%–71%, and the volume ratio of each component is hydrofluoric acid:nitric acid:ulpure water = 3:5:92; as shown in Table 1 below, the content of each element is listed. A PFA beaker is selected as the corrosion-resistant container, and its initial mass M0 is weighed to be 24.12g. The cleaned and dried lint-free cloth is then placed in the container. The PFA cloth was placed in a PFA beaker, and the total mass M1 was measured to be 9.29 g. 100.00 mL of the soaking solution was added to completely submerge the cleanroom cloth. The PFA beaker was placed on a heating plate and heated at 50-70°C for 5-15 minutes. In this embodiment, the preferred condition is to heat at 60°C for 10 minutes to allow the metal and other impurity elements in the cleanroom cloth to be fully released into the solution under the synergistic effect of the mixed acid and the heating conditions. After the treatment, the cleanroom cloth was removed using a clean clamp to obtain the solution to be tested.

[0022] Table 1. Content of each element The test solution was analyzed using inductively coupled plasma optical emission spectrometry (ICP-OES), and a blank experiment was performed simultaneously to obtain the test results C1 and C0. Based on the test results, the soaking liquid volume V, and the mass difference (M1-M0), the content of each element in the cleanroom cloth was calculated according to the formula W=(C1-C0)×V / (M1-M0). Through the above specific implementation method, the dissolution efficiency of impurity elements in different forms is improved by utilizing the effect of hydrofluoric acid on inorganic structures and the oxidation effect of nitric acid. At the same time, the low background characteristics of PFA beaker and the high sensitivity detection capability of ICP-OES reduce external contamination and detection errors, making the measured results more accurate and reliable.

[0023] The description herein is provided to enable those skilled in the art to implement or use the present disclosure. Various modifications to the present disclosure will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other variations without departing from the scope of the disclosure. Therefore, this disclosure is not limited to the examples and designs described herein, but should be given the broadest scope consistent with the principles and novel features disclosed herein.

[0024] Although one or more exemplary embodiments of this disclosure have been described with reference to the accompanying drawings, those skilled in the art will understand that various changes in form and detail may be made therein without departing from the spirit and scope of this disclosure as defined by the appended claims.

[0025] The foregoing description is merely illustrative of this disclosure, and modifications may be made to the invention in light of the above detailed description. The terminology used in the appended claims should not be construed as limiting the invention to the specific embodiments disclosed in the specification. Rather, the scope of the invention will be fully defined by the appended claims, which will be interpreted according to established principles of claim interpretation.

Claims

1. A method for detecting metals and other impurities in cleanroom wipes, characterized in that, Includes the following steps: Weigh the initial mass M0 of the corrosion-resistant container, place the cleanroom cloth to be tested into the container and measure the total mass M1; add soaking solution to the container to completely submerge the cleanroom cloth; The container is placed on a heating device for constant temperature heating treatment, so that the metal and other impurity elements in the cleanroom cloth are released into the soaking solution. After the treatment is completed, the cleanroom cloth is taken out to obtain the solution to be tested. The elemental content of the test solution was determined, and a blank test was performed simultaneously to obtain the test results C1 and C0, respectively. Based on the test results, the volume of the soaking solution, and the mass difference, the content of each element in the cleanroom cloth is calculated.

2. The detection method according to claim 1, characterized in that: The soaking solution is a mixed acid solution prepared by mixing hydrofluoric acid, nitric acid and ultrapure water.

3. The detection method according to claim 2, characterized in that: The volume ratio of each component in the soaking solution is hydrofluoric acid: nitric acid: ultrapure water = 3:5:

92.

4. The detection method according to claim 2 or 3, characterized in that: The hydrofluoric acid has a mass fraction of 48.8%-49.2%, and the nitric acid has a mass fraction of 69%-71%.

5. The detection method according to claim 1, characterized in that: The heat treatment temperature is 50-70℃, and the heating time is 5-15 minutes.

6. The detection method according to claim 1, characterized in that: The elemental content was determined using inductively coupled plasma atomic emission spectrometry.

7. The detection method according to claim 1, characterized in that: The corrosion-resistant container is a PFA beaker.

8. The detection method according to claim 1, characterized in that: The content of each element in the cleanroom cloth is calculated based on the test results, the volume V of the soaking liquid, and the mass difference. The content of each element is calculated according to the following formula: W=(C1-C0)×V / (M1-M0), where W is the element content in the cleanroom cloth; M1-M0 is the mass difference; and V is the volume of the soaking liquid.

Images