Method for determining concentration of each component in mixed acid liquor of hydrofluoric acid, ammonium fluoride and acetic acid
By combining potentiometric titration with fluoride ion electrode, the problems of real-time and accuracy in detecting the concentration of mixed acid components were solved, and the component concentration of mixed acid solutions of hydrofluoric acid, ammonium fluoride and acetic acid was determined, thereby improving the stability of the etching process and the consistency of semiconductor devices.
Patent Information
- Application Number
- CN202511009254.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-22
- Publication Date
- 2025-09-12
AI Technical Summary
Existing technologies make it difficult to accurately detect the concentrations of each component in a mixed etching solution of hydrofluoric acid, ammonium fluoride, and acetic acid in real time, resulting in unstable etching effects and affecting the consistency and yield of semiconductor devices.
The method of potentiometric titration combined with fluoride ion electrode was used to determine the first and second jump points of the mixed acid solution of hydrofluoric acid, ammonium fluoride and acetic acid, and the mass fraction of each component was calculated in combination with the alkali solution and the solvent.
It achieves accurate measurement of the concentration of each component of the mixed acid solution, simplifies the operation process, and improves the stability of the etching process and the consistency of semiconductor devices.
Smart Images
Figure CN120629469A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of solution concentration analysis, and more particularly to a method for measuring the concentration of each component of a mixed acid etching solution. Background Art
[0002] In the semiconductor manufacturing process, semiconductor material surface treatment technology is one of the core processes in the manufacture of microelectronics and optoelectronic devices, which directly determines the electrical performance, reliability and integration of the device.
[0003] In hydrofluoric acid ( )、Ammonium fluoride( ) and acetic acid ( In the etching buffer system, the concentration ratio of each component is a key factor affecting the etching rate, selectivity and surface morphology. For example, too high HF concentration may lead to too fast etching rate, causing excessive surface roughness or local depression; the concentration of ammonium fluoride directly affects the buffer value and fluoride ion activity, thereby regulating the anisotropy of etching; acetic acid suppresses the local aggregation of etching by-products by adjusting the solution viscosity and reaction kinetics, thereby improving uniformity. However, the existing technology for monitoring the concentration of such etching solutions mostly relies on offline sampling combined with chemical titration or spectral analysis, which has problems such as poor real-time performance, cumbersome operation, and susceptibility to environmental interference, making it difficult to meet the process stability requirements of high-precision semiconductor manufacturing. Especially in the batch production process, the etching solution component concentration changes dynamically due to continuous consumption and accumulation of by-products. If real-time detection and feedback adjustment cannot be carried out, it will cause fluctuations in the etching effect between batches, resulting in increased discreteness of device performance and even product scrapping.
[0004] In addition, traditional detection methods are not effective in complex mixed systems (e.g. / / Ternary systems are susceptible to cross-interference from multiple components, making rapid, highly selective, and sensitive detection difficult, a bottleneck hindering the yield improvement of advanced semiconductor processes. Therefore, developing a technology that can accurately and non-destructively measure the concentrations of each component in the etching buffer in real time is of great engineering value for optimizing the etching process window, ensuring device consistency, and reducing production costs. Summary of the Invention
[0005] The main purpose of the present invention is to provide a method for measuring the concentration of each component in a mixed acid solution of hydrofluoric acid, ammonium fluoride and acetic acid, so as to solve the technical problems mentioned in the background technology.
[0006] The present invention provides a method for determining the concentration of each component in a mixed acid solution of hydrofluoric acid, ammonium fluoride and acetic acid, the method comprising the following steps: Step 1: Weigh a certain amount of mixed acid solution and disperse it in a solvent. Use alkali solution as titrant and measure the cumulative volume of alkali solution consumed at the first jump point of the mixed acid solution by potentiometric titration. The cumulative volume of alkali consumed at the second jump point ,in, The first jump point corresponds to all Neutralization reaction; The second hop point corresponds to middle reaction; Step 2: Weigh a certain amount of mixed acid solution and disperse it in the solvent. Use alkali solution as titrant and titrate the solution to the concentration of When the temperature is 6-7, a fluoride ion electrode is then used to Continue titrating the titrant. The consumption is ; Step 3: According to the mass of the mixed acid and 、 、 , titrant concentration, calculate 、 and quality score.
[0007] In the above technical solution, further, the alkali solution in step 1 and step 2 is or solution.
[0008] In any of the above technical solutions, further, the solvent in step 1 and step 2 is a non-aqueous solvent or an aqueous solvent.
[0009] In any of the above technical solutions, further, when the solvent is a non-aqueous solvent, the alkali solution is solution.
[0010] In any of the above technical solutions, further, the non-aqueous solvent is methanol or ethanol.
[0011] In any of the above technical solutions, further, the concentration of the alkali solution is 0.5-2 mol / L; The concentration is 0.1-0.5 mol / L.
[0012] In any of the above technical solutions, further, 、 and The quality score is calculated as follows: in, is the alkali concentration, for concentration, for Molar mass, for Molar mass, for Molar mass is the mass of the mixed acid solution in step 1, in g; is the mass of the mixed acid solution in step 2, in g, 、 、 The unit is ml.
[0013] Beneficial effects: Compared with the prior art, the method of the present invention can accurately determine the content of each component in an unconventional mixed acid system of hydrofluoric acid, ammonium fluoride and acetic acid. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0015] Figure 1 It is the titration curve figure of the first titration of Example; Figure 2 It is the titration curve diagram of the second titration of Example. DETAILED DESCRIPTION
[0016] Below, example embodiments according to the present application will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. It should be understood that the present application is not limited to the example embodiments described herein. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.
[0017] It should be noted that, as shown in this application and the claims, unless the context clearly indicates an exception, the words "a," "an," "an," and / or "the" do not refer to the singular and may include the plural. Generally speaking, the terms "comprise" and "include" only indicate the inclusion of the steps and elements specifically identified, and these steps and elements do not constitute an exclusive list. A method or apparatus may also include other steps or elements.
[0018] If the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), such directional indications are only used to explain the relative positional relationship, movement, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.
[0019] In the present invention, unless otherwise specified or limited, the terms "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can mean fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will be able to understand the specific meanings of the above terms in the present invention based on specific circumstances.
[0020] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the meaning of "and / or" appearing throughout the text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme in which A and B are satisfied at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.
[0021] Currently, no existing methods have been identified for measuring the content of each component in a mixture of hydrofluoric acid, ammonium fluoride, and acetic acid. This is because conventional titration methods often have difficulty distinguishing the identity of fluoride ions in hydrofluoric acid and ammonium fluoride. Therefore, the accuracy of the acid concentration measurement is of great importance. Based on this, this application proposes a method for accurately measuring the concentration of each component in the ternary mixed solution.
[0022] The present application proposes a method for determining the concentration of each component in a mixed acid solution of hydrofluoric acid, ammonium fluoride and acetic acid, the method comprising the following steps: Step 1: Weigh a certain amount of mixed acid solution and disperse it in a solvent. Use alkali solution as titrant and measure the cumulative volume of alkali solution consumed at the first jump point of the mixed acid solution by potentiometric titration. The cumulative volume of alkali consumed at the second jump point ,in, The first jump point corresponds to all Neutralization reaction; The second hop point corresponds to middle reaction; Step 2: Weigh a certain amount of mixed acid solution and disperse it in the solvent. Use alkali solution as titrant and titrate the solution to When the temperature is 6-7, a fluoride ion electrode is then used to Continue titrating the titrant. The consumption is ; Step 3: According to the mass of the mixed acid and 、 、 , titrant concentration, calculate 、 and quality score.
[0023] In step 1, there will be two obvious jump points, corresponding to the first jump point and the second jump point; when all the The first jump point (i.e. the first jump point) appears when the alkali solution is neutralized. As the alkali solution continues to be titrated, the solution system Gradually overdose, it will middle A reaction occurs, and a second jump point (i.e., the second jump point) appears.
[0024] In step 2, you can Titrate the total The molar amount of .
[0025] Optimized, the alkali solution in step 1 and step 2 is or solution.
[0026] Optimally, the solvent in step 1 and step 2 is a non-aqueous solvent or an aqueous solvent.
[0027] It should be noted that when the solvent is a non-aqueous solvent, the alkali solution is solution; when the solvent is aqueous, the alkali solution is or Any solution is acceptable. The solubility of the product produced by titration of the solution in non-aqueous solvents is low, which leads to the formation of precipitation that interferes with the test accuracy. The solution is best used for titration of aqueous solvents.
[0028] Optimized, non-aqueous solvents are methanol or ethanol.
[0029] Optimally, the concentration of alkali solution is 0.5-2 mol / L; The concentration is 0.1-0.5 mol / L.
[0030] The above method enables precise measurement of the mass fractions of the various components of the mixed acid solution. Furthermore, the method is simple to operate, requiring no pretreatment of the liquid being tested, and can determine the concentrations of the various components of the ternary mixed solution in a maximum of two titration steps.
[0031] about 、 and The quality score is calculated as follows: in, is the alkali concentration, for concentration, for Molar mass, for Molar mass, for Molar mass is the mass of the mixed acid solution in step 1, in g; is the mass of the mixed acid solution in step 2, in g, 、 、 The unit is ml.
[0032] The method of the present application is tested by the following examples.
[0033] Example 1: Configuration 9.5±0.1% , 19.5±0.5% and 20±0.5% The mixed solution was titrated.
[0034] 1. Take 1.082g of mixed acid solution and disperse it in water. Electrode, 1 mol / L It is titrated as a titrant, and the titration curve is as follows Figure 1 As shown, at this time ml, ml, then according to formula (1) we can get: Formula (1) 2. Take 0.529g of mixed acid solution and disperse it in water. First use Electrode, 1 mol / L As titrant adjustment to 6 o'clock, then switch to the fluoride ion electrode and use 0.1 mol / L It is titrated as a titrant, and the titration curve is as follows Figure 2 As shown, at this time ml, according to formula (2) and formula (3), we can get: Formula (2) Formula (3) It should be noted that the use of mol / L, mol / L, Calculations are performed using mol / L.
[0035] about Using a concentration of 1 mol / L, A concentration of 0.1 mol / L was used.
[0036] It should be noted that high concentrations can provide enough ions, ensuring strong jump signal: quickly neutralizes ( and ),make The jump point detected by the electrode ( 、 ) is more significant, reducing errors; low concentration This may cause the titration curve to be flat and the jump point to be difficult to determine (especially for weak acids titration) so 1 mol / L was used Of course, titration can also be performed using alkali solutions of other concentrations, and is not limited to this concentration.
[0037] It should be noted that, on the one hand, and generate The reaction sensitivity of the precipitation is extremely high ( ), even at low concentrations (0.1 mol / L) can also clearly detect potential jumps. On the other hand, high concentrations This may cause local supersaturation precipitation, affecting the electrode response speed or blocking the liquid path. Of course, titration can also be performed using alkali solutions of other concentrations, and is not limited to this concentration.
[0038] The mass fractions of the various components of the acid solution measured by the above data and formula are The mass fraction is 9.58%, The mass fraction is 19.2%, The mass fraction of hydrofluoric acid is 20.12%, and the measured result is within the error range of the solution preparation. Therefore, this method can achieve the )、Ammonium fluoride( ) and acetic acid ( ) Measurement of this unconventional ternary system mixed solution.
[0039] While various embodiments of the present disclosure have been described above, the above descriptions are illustrative, non-exhaustive, and not intended to be limiting of 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 selected to best explain the principles of the embodiments, their practical applications, or improvements to existing technologies, or to enable others skilled in the art to understand the embodiments disclosed herein.
Claims
1. A method for determining the concentration of each component in a mixed acid solution of hydrofluoric acid, ammonium fluoride and acetic acid, characterized in that: The method comprises the following steps: Step 1: Weigh a certain amount of mixed acid solution and disperse it in a solvent. Use alkali solution as titrant and measure the cumulative volume of alkali solution consumed at the first jump point of the mixed acid solution by potentiometric titration. The cumulative volume of alkali consumed at the second jump point ,in, The first hop point corresponds to all Neutralization reaction; The second hop point corresponds to middle reaction; Step 2: Weigh a certain amount of mixed acid solution and disperse it in the solvent. Use alkali solution as titrant and titrate the solution to the concentration of When the temperature is 6-7, a fluoride ion electrode is then used to Continue titrating the titrant. The consumption is ; Step 3: According to the mass of the mixed acid and 、 、 , titrant concentration, calculate 、 and quality score.
2. The method for measuring the concentration of each component in a mixed acid solution of hydrofluoric acid, ammonium fluoride and acetic acid as claimed in claim 1, wherein: The alkali solution in step 1 and step 2 is or solution.
3. The method for measuring the concentration of each component in a mixed acid solution of hydrofluoric acid, ammonium fluoride and acetic acid as claimed in claim 2, wherein: The solvent in step 1 and step 2 is a non-aqueous solvent or an aqueous solvent.
4. The method for measuring the concentration of each component in a mixed acid solution of hydrofluoric acid, ammonium fluoride and acetic acid as claimed in claim 3, wherein: When the solvent is non-aqueous solvent, the alkali solution is solution.
5. The method for measuring the concentration of each component in a mixed acid solution of hydrofluoric acid, ammonium fluoride and acetic acid as claimed in claim 3, wherein: The non-aqueous solvent is methanol or ethanol.
6. The method for measuring the concentration of each component in a mixed acid solution of hydrofluoric acid, ammonium fluoride and acetic acid as claimed in claim 1, wherein: The concentration of the alkali solution is 0.5-2 mol / L; The concentration is 0.1-0.5 mol / L.
7. The method for measuring the concentration of each component in a mixed acid solution of hydrofluoric acid, ammonium fluoride and acetic acid according to any one of claims 1 to 6, wherein: 、 and The quality score is calculated as follows: in, is the alkali concentration, for concentration, for Molar mass, for Molar mass, for Molar mass is the mass of the mixed acid solution in step 1, in g; is the mass of the mixed acid solution in step 2, in g, 、 、 The unit is ml.