Method for rapidly evaluating suspension property of polishing solution by utilizing absorbance of suspension layer

Abstract

The invention discloses a method for quickly evaluating the suspension property of a polishing solution by using the absorbance of a suspension layer, which comprises the following steps: preparing the polishing solution from polishing powder with a certain particle size span, and standing; in the standing time period of the polishing solution, part of the suspension solution located in the suspension layer of the polishing solution at different time points is taken out and correspondingly diluted; the absorbance of the diluted suspension solution is tested, the change relation between the absorbance of the suspension layer and the selection time is detected, the suspension property of the prepared polishing solution is evaluated according to the change relation, and the suspension property of the polishing solution is inversely proportional to the change rate of the change relation between the absorbance of the suspension layer and the selection time. Therefore, more accurate quantitative data can be provided, and data support is provided for production guidance, scientific research and industrial standard establishment.

Description

Technical Field

[0001] The present invention relates to the technical field of polishing fluids, and particularly to a method for rapidly evaluating the suspension property of a polishing fluid by using the absorbance of a suspension layer. Background Art

[0002] Current polishing fluids play a crucial role in industrial manufacturing and are widely used in fields such as semiconductors, optics, and metal processing. Their dispersibility directly affects the polishing effect, processing efficiency, and the quality of the final product. To ensure the performance of the polishing fluid, evaluating its dispersibility has become an important link in research and production. The traditional observation method is widely adopted because of its simplicity and feasibility. For example, in research such as "Research and Improvement on the Suspension and Dispersion Properties of CeO2 Polishing Fluids" and "Research on the Suspension and Redispersion Properties of Cerium Oxide Polishing Fluids", the observation method was used to analyze the dispersibility of the polishing fluid.

[0003] In the process of implementing the present invention, the inventors found that the observation method has at least the following technical problems in practical applications: 1. The subjectivity of the observation method is relatively strong. The experience and judgment of the evaluator will affect the observation results, resulting in inconsistent results among different experimenters. This subjectivity not only reduces the reliability of the experiment but also makes it difficult to compare the results in different laboratories or production environments.

[0004] 2. The observation method lacks quantitative data and mainly relies on visual inspection, unable to accurately reflect the concentration of particles in the polishing fluid. To a certain extent, this limits the comprehensive understanding and optimization of the performance of the polishing fluid.

[0005] 3. The observation method usually requires a long time for evaluation, especially when analyzing multiple samples, and the efficiency is relatively low. In a fast-paced industrial environment, this low efficiency may affect the production schedule and increase production costs. Environmental factors will also affect the observation results. For example, changes in conditions such as temperature, humidity, and light may cause fluctuations in the observation results, further affecting the repeatability and reliability of the experiment.

[0006] Therefore, there is an urgent need to establish a more scientific and efficient method for evaluating the dispersibility of polishing fluids to solve the problems of strong subjectivity, inability to comprehensively understand and optimize the performance of polishing fluids, long time, and low efficiency existing in the current observation method. Summary of the Invention

[0007] To solve the above technical problems, an embodiment of the present invention provides a method for rapidly evaluating the suspension property of a polishing fluid by using the absorbance of a suspension layer. The specific technical solution is as follows: To solve the above technical problems, the present invention is implemented as follows: A method for rapidly evaluating the suspension property of a polishing liquid by using the absorbance of the suspension layer is provided, which includes the following steps: preparing a polishing liquid with polishing powder having a certain particle size span and allowing it to stand; during the period when the polishing liquid stands, taking out partial suspension solutions from the suspension layer of the polishing liquid at different time points and diluting them correspondingly; testing the absorbance of the diluted suspension solutions, detecting the change relationship between the absorbance of the suspension layer and the selected time, and evaluating the suspension property of the prepared polishing liquid according to the change relationship, wherein the suspension property of the polishing liquid is inversely proportional to the change rate of the change relationship between the absorbance of the suspension layer and the selected time.

[0008] In one embodiment, the mass concentration range of the polishing powder in the prepared polishing liquid is 1% - 30%.

[0009] In one embodiment, the mass concentration range of the polishing powder in the prepared polishing liquid is preferably 10% - 20%.

[0010] In one embodiment, within 0 - 1 h after standing, the polishing liquid has an obvious suspension layer, and the volume ratio of the suspension layer to the total volume of the polishing liquid is 90 - 100%.

[0011] In one embodiment, the volume ratio of the suspension layer to the total volume of the polishing liquid is preferably 98 - 100%.

[0012] In one embodiment, the median particle size of the selected polishing powder is 0.1 - 9 microns.

[0013] In one embodiment, the median particle size of the selected polishing powder is preferably 0.6 - 2 microns.

[0014] In one embodiment, the taken-out suspension solution is located at the middle position of the suspension layer of the polishing liquid.

[0015] In one embodiment, the volume of the taken-out suspension solution is 1 - 5 ml, and it is diluted to make its concentration meet the test range of the instrument for detecting absorbance.

[0016] In one embodiment, when detecting the change relationship between the absorbance of the suspension layer and the selected time, the range of the selected time is 0 - 60 min, and the absorbance of the selected corresponding suspension solution is tested at different time points within the selected time range to establish a change relationship curve between the absorbance of the suspension layer and the selected time.

[0017] In the embodiments of the present invention, by establishing the relationship between the absorbance of the suspension layer of the configured polishing liquid during the standing process and the selected time, and evaluating the suspension property of the configured polishing liquid according to this relationship, thus, more accurate quantitative data can be provided to support data for guiding production, scientific research, and the establishment of industry standards. The evaluation method of the present invention can significantly shorten the evaluation time, improve the experimental efficiency, and has the advantages of being fast, accurate, and scientific. Compared with the current observation method, the instrumental analysis of the method of the present invention not only reduces human error, but also provides more consistent results under different conditions, ensuring the repeatability of the results. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings described herein are used to provide a further understanding of the present invention, and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings: Figure 1 is a flowchart of the steps of the method for rapidly evaluating the suspension property of a polishing liquid by using the absorbance of the suspension layer of the present invention; Figure 2 is a graph showing the relationship between the absorbance of the suspension layer and the selected time of Example 1 and Comparative Example 1 of the present invention; Figure 3 is a graph showing the relationship between the absorbance of the suspension layer and the selected time of Example 2 and Comparative Example 2 of the present invention; Figure 4 is a graph showing the relationship between the absorbance of the suspension layer and the selected time of Example 3 and Comparative Example 3 of the present invention; Figure 5 is a graph showing the relationship between the absorbance of the suspension layer and the selected time of Example 4 and Comparative Example 4 of the present invention; Figure 6 is a graph showing the suspension situation after standing for 60 minutes of Examples 1-4 and Comparative Examples 1-4 of the present invention; Figure 7 is a graph showing the suspension situation after standing for 48 hours of Examples 1-4 and Comparative Examples 1-4 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0020] Please refer to Figure 1, which is the step flow chart of the method for rapidly evaluating the suspension property of a polishing liquid by using the absorbance of a suspension layer according to the present invention; as shown in the figure, the method for rapidly evaluating the suspension property of a polishing liquid by using the absorbance of a suspension layer in this embodiment includes the following steps S1 to S3. First, in step S1, a polishing liquid is prepared: polishing powder with a certain particle size span is taken to prepare the polishing liquid and allowed to stand. The particle size span refers to the value of (D90 - D10) / D50, where D90 is the maximum particle size of the polishing powder, D10 is the minimum particle size of the polishing powder, D50 is the median particle size of the polishing powder, and the larger the value of the particle size span, the more obvious the removal effect of the large particles by this method. The median particle size D50 of the selected polishing powder is 0.1 to 9 μm, preferably 0.6 to 2 μm. The mass concentration range of the polishing powder in the prepared polishing liquid is 1% to 30%, preferably 10% to 20%.

[0021] Next, in S2, measurement liquids are taken from the polishing liquid at different time points: during the period when the polishing liquid is standing, different time points are selected to respectively take a part of the suspension solution from the suspension layer of the polishing liquid and dilute it correspondingly. The polishing liquid has an obvious suspension layer within 0 - 1 h of standing, and the volume ratio of its suspension layer to the total volume of the polishing liquid is 90% - 100%, preferably 98% - 100%. The taken suspension solution is located in the middle position of the suspension layer of the polishing liquid, and the volume of the taken suspension solution is 1 - 5 ml, and it is diluted to make its concentration meet the test range of the instrument for detecting absorbance.

[0022] Finally, in S3, the suspension property of the polishing liquid is evaluated: the absorbance of the diluted suspension solution is measured, the change relationship between the absorbance of the suspension layer and the selected time is detected, and the suspension property of the prepared polishing liquid is evaluated according to the change relationship. The range of the selected time is 0 - 60 min, and the absorbance of the selected corresponding suspension solution is measured at different time points within the selected time range to establish a change relationship curve between the absorbance of the suspension layer and the selected time. The suspension property of the polishing liquid is inversely proportional to the change rate of the change relationship between the absorbance of the suspension layer and the selected time, that is, the change rate is obtained according to the change relationship, and the smaller the change rate, the better its suspension property.

[0023] The method for rapidly evaluating the suspension property of a polishing liquid by using the absorbance of a suspension layer in this embodiment evaluates the suspension property of the prepared polishing liquid according to the change relationship between the absorbance of the suspension layer and the selected time during the standing process of the prepared polishing liquid. In this way, more accurate quantitative data can be provided, providing data support for guiding production, scientific research, and the establishment of industry standards. The evaluation method in this embodiment can significantly shorten the evaluation time, improve the experimental efficiency, and has the advantages of being fast, accurate, and scientific. Compared with the current observation method, the instrument analysis in this embodiment not only reduces human error but also provides more consistent results under different conditions, ensuring the repeatability of the results.

[0024] The beneficial effects of the method for rapidly evaluating the suspension property of a polishing liquid by using the absorbance of a suspension layer according to the present invention will be described below with specific embodiments.

[0025] Example 1 1. Prepare a polishing liquid with a mass concentration of 20% by formulating cerium oxide powder (D50 = 0.645 μm) according to a certain formula; 2. There is an obvious suspension layer within 0 - 1 h after the preparation of the polishing liquid, and the proportion of the suspension layer in the total volume is greater than 98%. At the time points of 0, 15, 30, 45, and 60 min, respectively, select 0.3 ml of liquid from the middle of the suspension layer of the two polishing liquids and dilute it with 10 ml of water; 3. Use a UV - visible spectrophotometer to measure the absorbance of the diluted liquid, and establish a curve of the change relationship between the absorbance of the suspension layer and the selected time. The specific values are shown in Table 1, and the change results are as Figure 1 shown.

[0026] Among them, in Comparative Example 1, 0.3 ml of acetic acid was added to change the suspension property of the polishing liquid. Both polishing liquids had an obvious suspension layer within 0 - 1 h after preparation, and the proportion of the suspension layer in the total volume was greater than 98%, and there was no obvious clarification layer or precipitation layer. At the time points of 0, 15, 30, 45, and 60 min, respectively, select 0.3 ml of liquid from the middle of the suspension layer of the two polishing liquids and dilute it with 10 ml of water, and then use a UV - visible spectrophotometer to measure the absorbance of the diluted liquid, and establish a curve of the change relationship between the absorbance of the suspension layer and the selected time. The specific values are shown in Table 1, and the change results are as Figure 2 shown.

[0027] Table 1: Control Example 1 The difference between this Control Example 1 and the above - mentioned Example 1 is that 0.3 ml of acetic acid was added during the preparation of the polishing liquid to change the suspension property of the polishing liquid. Other conditions are the same as those in Example 1. Therefore, the steps of this Control Example 1 refer to those shown in the above - mentioned Example 1 and will not be elaborated here.

[0028] It can be seen from Table 1 that the absorbances of Example 1 and Comparative Example 1 decreased from 3.896 and 3.913 to 3.816 and 3.704 respectively, and the change rates of the two were 2.05% and 5.34% respectively. It can also be clearly seen from Figure 2 that the curve change rate of Comparative Example 1 is more obvious. Therefore, it can be obtained by this method that the suspension property of the polishing liquid in Example 1 is better than that in Comparative Example 1.

[0029] From Figure 6It can be seen that within 1 hour after the two polishing liquids of Example 1 and Comparative Example 1 are prepared, there are obvious suspension layers, and the volume ratio of the suspension layer to the total volume is greater than 98%, without obvious clarification layers and sediment layers. Therefore, in this case, by using the observation method, it is impossible to quickly judge the suspension dispersibility of the two samples within 1 hour.

[0030] As can be seen from Figure 7 it, after the two polishing liquids of Example 1 and Comparative Example 1 are left standing for 48 hours, the clarification layer that appears in Example 1 is significantly smaller than that in Comparative Example 1. Therefore, the suspension property of Example 1 is better than that of Comparative Example 1. Therefore, according to this method, it is possible to quickly, accurately and scientifically evaluate the suspension dispersibility of the two samples within 1 hour.

[0031] Example 2 1. Prepare a polishing liquid with a mass concentration of 30% by formulating cerium oxide powder (D50 = 0.645 microns) according to a certain formula; 2. Within 0 - 1 hour after the polishing liquid is prepared, there is an obvious suspension layer, and the volume ratio of the suspension layer to the total volume is greater than 98%, without obvious clarification layers and sediment layers. At the time points of 0, 15, 30, 45, and 60 minutes, respectively, select 0.3 ml of liquid from the middle of the suspension layer of the two polishing liquids and dilute it with 10 ml of water; 3. Use a UV-visible spectrophotometer to measure the absorbance of the diluted liquid, and establish a curve of the change relationship between the absorbance of the suspension layer and the selected time. The specific values are shown in Table 1, and the change results are as Figure 3 shown.

[0032] Control Example 2 The difference between this Control Example 2 and the above Example 2 is that 0.3 ml of acetic acid is added during the preparation of the polishing liquid to change the suspension property of the polishing liquid. Other conditions are the same as those in Example 2. Therefore, the steps of this Control Example 2 are referred to those shown in the above Example 2 and will not be elaborated here.

[0033] As can be seen from Table 1, the absorbances of Example 2 and Control Example 2 decrease from 4.027 and 4.086 to 3.227 and 2.803 respectively, and the change rates of the two are 19.866% and 31.400% respectively. As can also be clearly seen from Figure 3 it, the curve change rate of Control Example 2 is more obvious. Therefore, it can be obtained by this method that the suspension property of the polishing liquid of Example 2 is better than that of Control Example 2.

[0034] As can be seen from Figure 6 it, within 1 hour after the two polishing liquids are prepared, there are obvious suspension layers, and the volume ratio of the suspension layer to the total volume is greater than 98%, without obvious clarification layers and sediment layers. Therefore, in this case, by using the observation method, it is impossible to quickly judge the suspension dispersibility of the two samples within 1 hour.

[0035] From Figure 7 It can be seen that after the two polishing liquids of Example 2 and Comparative Example 2 were left standing for 48 hours, the clear layer that appeared in Example 2 was significantly smaller than that in Comparative Example 2. Therefore, the suspension property of Example 2 is better than that of Comparative Example 2. Therefore, according to this method, the suspension dispersibility of two samples can be quickly, accurately and scientifically evaluated within 1 h.

[0036] Example 3 1. Prepare a polishing liquid with a mass concentration of 1% by formulating cerium oxide powder (D50 = 0.645 μm) according to a certain formula; 2. There is an obvious suspension layer within 0 - 1 h after the polishing liquid is prepared, and the proportion of the suspension layer in the total volume is greater than 98%, without obvious clear layer and precipitation layer. At the time nodes of 0, 15, 30, 45, and 60 min, select 0.3 ml of liquid from the middle of the suspension layer of the two polishing liquids and dilute it with 10 ml of water; 3. Use an ultraviolet-visible spectrophotometer to measure the absorbance of the diluted liquid, and establish a curve of the change relationship between the absorbance of the suspension layer and the selected time. The specific values are shown in Table 1, and the change results are as Figure 4 shown.

[0037] Comparative Example 3 The difference between this Comparative Example 3 and the above Example 3 is that 0.3 ml of acetic acid is added during the preparation of the polishing liquid to change the suspension property of the polishing liquid. Other conditions are the same as those in Example 3. Therefore, the steps of this Comparative Example 3 are referred to those shown in the above Example 3 and will not be elaborated here.

[0038] It can be seen from Table 1 that the absorbances of Example 3 and Comparative Example 3 decreased from 0.369 and 0.306 to 0.317 and 0.239 respectively, and the change rates of the two were 14.092% and 21.895% respectively. From Figure 4 it can also be clearly seen that the curve change rate of Comparative Example 3 is more obvious. Therefore, it can be obtained by this method that the suspension property of the polishing liquid in Example 3 is better than that in Comparative Example 3.

[0039] From Figure 6 it can be seen that both polishing liquids have an obvious suspension layer within 1 h after being prepared, and the proportion of the suspension layer in the total volume is greater than 98%, without obvious clear layer and precipitation layer. Therefore, in this case, by using the observation method, it is impossible to quickly judge the suspension dispersibility of the two samples within 1 h.

[0040] From Figure 7It can be seen that after standing for 48 hours, the clear layer in Example 3 is significantly smaller than that in Comparative Example 3. Therefore, the suspension property of Example 3 is better than that of Comparative Example 3. Thus, according to this method, the suspension dispersibility of two samples can be quickly, accurately and scientifically evaluated within 1 hour.

[0041] Example 4 1. Prepare a polishing liquid with a mass concentration of 20% by formulating cerium oxide powder (D50 = 9.289 microns) according to a certain formula; 2. There is an obvious suspension layer within 0 - 1 hour after the polishing liquid is prepared. The proportion of the suspension layer in the total volume is greater than 98%, and there is no obvious clear layer or precipitation layer. At the time nodes of 0, 15, 30, 45, and 60 minutes, select 0.3 ml of liquid from the middle of the suspension layer of the two polishing liquids and dilute it with 10 ml of water; 3. Use an ultraviolet - visible spectrophotometer to measure the absorbance of the diluted liquid, and establish a curve of the change in the absorbance of the suspension layer versus the selected time. The specific values are shown in Table 1, and the change results are as Figure 5 shown.

[0042] Comparative Example 4 The difference between this Comparative Example 4 and the above Example 4 is that 0.3 ml of acetic acid is added during the preparation of the polishing liquid to change the suspension property of the polishing liquid. Other conditions are the same as those in Example 4. Therefore, the steps of this Comparative Example 4 refer to those shown in the above Example 4 and will not be elaborated here.

[0043] It can be seen from Table 1 that the absorbances of Example 4 and Comparative Example 4 decrease from 1.427 and 1.449 to 0.289 and 0.133 respectively, and the change rates of the two are 79.748% and 90.821% respectively. From Figure 5 it can also be clearly seen that the curve change rate of Comparative Example 4 is more obvious. Therefore, it can be concluded by this method that the suspension property of the polishing liquid in Example 3 is better than that in Comparative Example 3.

[0044] From Figure 6 it can be seen that both polishing liquids have an obvious suspension layer within 1 hour after being prepared. The proportion of the suspension layer in the total volume is greater than 98%, and there is no obvious clear layer or precipitation layer. Therefore, in this case, by using the observation method, it is impossible to quickly judge the suspension dispersibility of the two samples within 1 hour.

[0045] From Figure 7 it can be seen that after standing for 48 hours, the clear layer in Example 4 is significantly smaller than that in Comparative Example 4. Therefore, the suspension property of Example 4 is better than that of Comparative Example 4. Thus, according to this method, the suspension dispersibility of two samples can be quickly, accurately and scientifically evaluated within 1 hour.

[0046] In summary, the present invention provides a method for separating the polishing liquid into upper and lower layers by establishing the relationship between the absorbance of the suspension layer in the static polishing liquid after configuration and the selected time, and selecting a suitable time point according to the change relationship. The upper layer of the polishing liquid is retained, and the lower layer of the polishing liquid is removed. In this way, the large-particle powder in the polishing liquid is removed by removing the lower separated liquid of the polishing liquid, making the particle size in the polishing liquid more concentrated, improving the stability of the polishing liquid and optimizing the polishing effect. The method of the present invention has the advantages of being fast, scientific, low-cost and high-efficiency.

[0047] It should be noted that in this article, the term "including", "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of additional identical elements in the process, method, article or device including that element.

[0048] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the above specific embodiments. The above specific embodiments are merely illustrative and not restrictive. Under the inspiration of the present invention, those of ordinary skill in the art can also make many forms without departing from the purpose of the present invention and the scope protected by the claims, and all of them belong to the protection scope of the present invention.

Claims

1. A method for quickly evaluating the suspension property of a polishing liquid by using the absorbance of a suspension layer, characterized in that: The following steps are involved: Take polishing powder with a certain particle size span to prepare polishing liquid and let it stand; During the period of time when the polishing liquid is left to stand, taking out parts of the suspension solution from the suspension layer of the polishing liquid at different time points, and diluting them accordingly; The absorbance of the diluted suspension solution is tested, and the relationship between the absorbance of the suspension layer and the selection time is detected. The suspension property of the configured polishing liquid is evaluated based on the change relationship, wherein the suspension property of the polishing liquid is inversely proportional to the rate of change of the relationship between the absorbance of the suspension layer and the selection time.

2. The method for rapidly evaluating the suspension property of a polishing liquid by using the absorbance of a suspension layer according to claim 1, characterized in that: The mass concentration range of the polishing powder in the configured polishing liquid is 1% to 30%.

3. The method for rapidly evaluating the suspension property of a polishing liquid by using the absorbance of a suspension layer according to claim 1 or 2, characterized in that: The mass concentration range of the polishing powder in the configured polishing liquid is preferably 10% to 20%.

4. The method for rapidly evaluating the suspension property of a polishing liquid by using the absorbance of a suspension layer according to claim 1, characterized in that: The polishing liquid has an obvious suspension layer within 0-1h of standing, and the suspension layer accounts for 90-100% of the total volume of the polishing liquid.

5. The method for rapidly evaluating the suspension property of a polishing liquid by using the absorbance of a suspension layer according to claim 4, characterized in that: The suspension layer preferably accounts for 98-100% of the total volume of the polishing liquid.

6. The method for rapidly evaluating the suspension property of a polishing liquid by using the absorbance of a suspension layer according to claim 1, characterized in that: The median particle size of the selected polishing powder is 0.1 to 9 microns.

7. The method for rapidly evaluating the suspension property of a polishing liquid by using the absorbance of a suspension layer according to claim 1 or 6, characterized in that: The median particle size of the selected polishing powder is preferably 0.6 to 2 microns.

8. The method for rapidly evaluating the suspension property of a polishing liquid by using the absorbance of a suspension layer according to claim 1, characterized in that: The taken-out suspension solution is located in the middle of the suspension layer of the polishing liquid.

9. The method for rapidly evaluating the suspension property of a polishing liquid by using the absorbance of a suspension layer according to claim 1, characterized in that: The volume of the suspended solution taken out is 1-5 ml, and it is diluted so that its concentration meets the test range of the absorbance detection instrument.

10. The method for rapidly evaluating the suspension property of a polishing liquid by using the absorbance of a suspension layer according to claim 1, characterized in that: When detecting the relationship between the absorbance of the suspension layer and the selected time, the selected time range is 0~60min, and the absorbance of the selected corresponding suspension solution is tested at different time points within the selected time range to establish a curve of the relationship between the absorbance of the suspension layer and the selected time.

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