A zeta potential measuring device and method applied to semiconductor material and process development

Abstract

This invention discloses a zeta potential measurement device and method for semiconductor material and process development, belonging to the field of surface electrochemical measurement and semiconductor material characterization technology. The device includes a sample rotation unit for fixing and rotating the sample to be tested; a liquid delivery unit including a working electrode, a pump, and a liquid container; the working electrode is connected to the liquid container via the pump to deliver the liquid to be tested to the surface of the sample to form a liquid layer; an electrode measurement unit including a reference electrode disposed around the sample to detect the current potential generated in the liquid layer due to sample rotation; and a signal processing unit connected to the electrode measurement unit to calculate the zeta potential of the sample surface based on the current potential. This invention achieves high signal-to-noise ratio measurement of single, irregular samples in complex semiconductor liquids, without requiring known Debye lengths, and with short liquid exposure time, significantly improving the adaptability, accuracy, and efficiency of the measurement.

Description

Technical Field

[0001] This invention relates to the field of surface electrochemical measurement and semiconductor material characterization technology, specifically to a zeta potential measurement device and method applied to semiconductor material and process development. Background Technology

[0002] Zeta potential is a characterization of solid-state... The zeta potential at the liquid interface is a key parameter reflecting the charged state of a material surface in a liquid environment. It is crucial for predicting particle dispersion stability, surface adsorption behavior, filtration efficiency, and the stability of colloidal systems. In semiconductor manufacturing processes, such as chemical mechanical polishing (CMP), photolithography, and wet etching, the properties of the special liquids used—including polishing slurries, photoresists, and etching solutions—are closely related to the zeta potential of the material surface, directly affecting process performance and product quality.

[0003] Currently, the mainstream methods for measuring zeta potential mainly include electrophoresis and spin electrophoresis. Electrophoresis (such as the Surpass series instruments) requires two identical samples with smooth surfaces to form a capillary channel. Liquid flow is driven by a pressure difference, and the genomic potential is detected to calculate the zeta potential. This method has stringent requirements on sample shape, size, and surface smoothness, and requires knowledge of the Debye length (electron cloud thickness) in the liquid, making it difficult to apply in practical semiconductor process liquids (such as organic solvents and polymer solutions). Spin electrophoresis immerses a single sample in a liquid and rotates it, calculating the zeta potential by detecting the genomic potential caused by rotation. However, this method produces a weak signal in low-conductivity liquids, requiring extremely high rotation speeds to obtain a detectable signal. Furthermore, prolonged contact between the liquid and air can easily lead to changes in physicochemical properties, affecting measurement accuracy.

[0004] In semiconductor material development and process optimization, various complex liquid systems are often involved, such as polishing slurries containing nanoparticles, organic solvents used in photoresists (such as PGMEA, n-butanol, etc.), and etching solutions containing polymers. Existing instruments cannot achieve accurate and stable zeta potential measurements in these systems, leading to a reliance on trial and error in process development, resulting in long cycles and high costs.

[0005] To address the aforementioned issues, there is an urgent need for a zeta potential measurement device and method applicable to semiconductor material and process development, which can solve the problems existing in traditional methods. Summary of the Invention

[0006] The purpose of this invention is to provide a zeta potential measurement device and method for semiconductor material and process development. It achieves high signal-to-noise ratio measurement of single, irregular samples in complex semiconductor liquids, without requiring known Debye lengths and with short liquid exposure time, significantly improving the adaptability, accuracy and efficiency of the measurement, and solving the pain point of the industry's long-term reliance on trial and error in development.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A zeta potential measurement device for semiconductor material and process development includes: a sample rotation unit, a liquid delivery unit, an electrode measurement unit, and a signal processing unit; The sample rotation unit is used to fix and rotate the sample to be tested; The liquid delivery unit includes a working electrode, a pump, and a liquid container. The working electrode is connected to the liquid container via the pump and is used to deliver the liquid to be tested to the surface of the sample to be tested to form a liquid layer. The electrode measurement unit includes a reference electrode, which is disposed on the periphery of the sample to be tested and is used to detect the current potential generated in the liquid layer due to the rotation of the sample. The electrode measurement unit is connected to the signal processing unit, which is used to calculate the zeta potential of the sample surface based on the current potential.

[0008] Furthermore, the working electrode has a hollow internal structure, and its end is connected to the liquid container through a pipeline and a pump, which is used to spray the liquid to be tested onto the surface of the sample to be tested.

[0009] Furthermore, the sample rotation unit is a rotating rod.

[0010] Furthermore, an open container is provided on the lower side of the sample rotation unit for collecting the test liquid that falls onto the sample.

[0011] Furthermore, the electrode measurement unit also includes a voltmeter, and both the working electrode and the reference electrode are connected to the voltmeter.

[0012] Furthermore, both the reference electrode and the working electrode are made of silver or silver chloride, and their length is greater than 3 cm. The diameter of the reference electrode is 1-5 mm, the diameter of the working electrode is 3-5 mm, the internal hollow structure of the working electrode is 1-2 mm, and an insulating layer with a thickness of 1-2 mm is provided on the outer side of both the reference electrode and the working electrode. 1-3 mm of silver or silver chloride material is exposed at both ends of the reference electrode and the working electrode.

[0013] Furthermore, the top of the working electrode is 1-10 mm away from the test surface of the sample, and the exposed end of the reference electrode is used to contact the test liquid splashed out from the test surface of the sample.

[0014] Furthermore, the flow rate of the liquid to be tested ejected from the working electrode is 1-10 ml / s, and the rotation speed of the rotating rod is 1000-5000 rpm.

[0015] This invention also provides a zeta potential measurement method applied to semiconductor material and process development, which is applied to the aforementioned zeta potential measurement device for semiconductor material and process development, comprising: The sample to be tested is fixed on the sample rotation unit; The liquid delivery unit and sample rotation unit are activated to spray liquid onto the rotating sample surface through the working electrode, forming a liquid layer. The electrostatic potential generated in the liquid layer is detected by an electrode measurement unit; The zeta potential of the sample surface is calculated based on the current potential signal.

[0016] In summary, the present invention has at least one of the following beneficial technical effects: 1. Single sample measurement: Only one test surface is required, and no paired samples are needed. This is suitable for semiconductor R&D scenarios where materials are scarce, reducing the difficulty and cost of sample preparation.

[0017] 2. Strong adaptability to sample morphology: It supports the measurement of irregular and uneven surfaces (such as filter membranes, coatings, etc.), which expands the application range of zeta potential measurement.

[0018] 3. No need to know the Debye length: It overcomes the limitation of existing electrophoresis methods that require prior knowledge of the Debye length in the liquid, and is suitable for complex liquid systems where the Debye length is unknown or difficult to calculate.

[0019] 4. Significantly improved signal strength: By confining the liquid within a thin layer ranging from micrometers to millimeters in thickness, the cross-sectional area of ​​the electron cloud movement is reduced and the resistance is increased. According to Ohm's law, the current potential signal is significantly enhanced, reducing the dependence on rotational speed and improving the signal-to-noise ratio and measurement accuracy.

[0020] 5. Short contact time between liquid and air: The liquid is in a closed pipeline during transportation and is only briefly exposed after being sprayed onto the sample surface. This is suitable for measuring special liquids that are sensitive to oxygen and moisture, and avoids errors caused by changes in liquid properties.

[0021] 6. The system is easy to clean and maintain: The device has a simple structure, few flow path components, and is easy to disassemble and clean. It supports continuous measurement of various liquids, which improves the efficiency of use.

[0022] 7. Widely applicable to semiconductor liquid systems: Stable measurements can be achieved in various semiconductor process liquids such as aqueous solutions containing nanoparticles, organic solvents, and polymer organic solutions, providing a reliable characterization method for process development.

[0023] 8. Flexible and adjustable measurement parameters: Key parameters such as rotation speed and flow rate can be adjusted within a wide range to adapt to different liquid properties and measurement needs, improving the applicability and operability of the device. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the device of the present invention; Figure 2 This is a schematic diagram of the electron cloud movement on the surface to be tested. Figure 3 This is a flowchart illustrating the method of the present invention.

[0025] Reference numerals: 1. Working electrode; 2. Pump; 3. Liquid container; 4. Rotating rod; 5. Sample to be tested; 6. Reference electrode. Detailed Implementation

[0026] 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.

[0027] like Figure 1 As shown, the present invention provides a zeta potential measurement device for semiconductor material and process development, comprising: a sample rotation unit, a liquid delivery unit, an electrode measurement unit, and a signal processing unit; The sample rotation unit is used to fix and rotate the sample to be tested 5; The liquid delivery unit includes a working electrode 1, a pump 2 and a liquid container 3. The working electrode 1 is connected to the liquid container 3 through the pump 2, and is used to deliver the liquid to be tested to the surface of the sample 5 to form a liquid layer. The electrode measurement unit includes a reference electrode 6, which is disposed on the periphery of the sample 5 to be tested and is used to detect the current potential generated in the liquid layer due to the rotation of the sample. The electrode measurement unit is connected to the signal processing unit, which is used to calculate the zeta potential of the sample surface based on the current potential.

[0028] The working electrode 1 has a hollow structure inside, and its end is connected to the liquid container 3 through a pipeline and pump 2, which is used to spray the liquid to be tested onto the surface of the sample 5 to be tested.

[0029] The sample rotation unit is a rotating rod 4.

[0030] An open container is provided on the lower side of the sample rotation unit to collect the test liquid falling from the sample 5.

[0031] The electrode measurement unit also includes a voltmeter, and both the working electrode 1 and the reference electrode 6 are connected to the voltmeter.

[0032] The working electrode needs to be explained. The working electrode has two functions: 1. Transporting liquids; 2. Measure the potential below the sample. The reference electrode is located to the side of the sample (Figure 2). The current potential is calculated by subtracting the potential of the reference electrode from the potential of the measuring electrode.

[0033] Both the reference electrode 6 and the working electrode 1 are made of silver or silver chloride, with a length greater than 3 cm. The diameter of the reference electrode 6 is 1-5 mm, and the diameter of the working electrode 1 is 3-5 mm. The internal hollow structure of the working electrode 1 is 1-2 mm thick. An insulating layer with a thickness of 1-2 mm is provided on the outer side of both the reference electrode 6 and the working electrode 1, and 1-3 mm of silver or silver chloride material is exposed at both ends of both electrodes. The insulating layer can be made of polytetrafluoroethylene (PTFE) or soluble polytetrafluoroethylene (PFA).

[0034] The sample rotation unit also includes a disk, which is located at the bottom of the rotating rod 4. The sample to be tested 5 is fixed to the bottom of the disk with glue, and the diameter of the sample to be tested 5 is 1-5 cm.

[0035] The top of the working electrode 1 is 1-10 mm away from the surface of the sample 5 to be tested. The exposed end of the reference electrode 6 needs to be located far away from the measurement surface, but the exposed end needs to be in contact with the liquid that is thrown out.

[0036] The working electrode 1 ejects the liquid to be tested at a flow rate of 1-10 ml / s, and the rotating rod 4 rotates at a speed of 1000-5000 rpm.

[0037] In use, the working electrode 1 sprays the liquid to be tested onto the surface of the sample 5. Simultaneously, the sample rotation unit rotates the sample 5, creating a liquid coating on the surface. When the liquid moves to the periphery of the sample 5, it falls due to gravity into an open container for collection. Some of the liquid comes into contact with the reference electrode 6 during rotation. Within this liquid coating, a surface charge is still formed on the measured surface. Outside this surface charge, there is still an equal and opposite electron cloud, such as... Figure 1As shown, the boundary of the electron cloud can be seen. In this case, the electron cloud will move from the middle of the surface to the outer edge of the surface, thus forming a current potential. Both the reference electrode 6 and the working electrode 1 are connected to a voltmeter. The intensity of the current potential can be known by the difference between the values ​​measured by the working electrode and the reference electrode 6, and then the zeta potential of the surface can be derived.

[0038] The motion of the electron cloud on the measured surface using the method described in this invention is as follows: Figure 2 As shown, in this method, similar to ordinary rotational electrophoresis, the electron cloud moves from the center of the measured surface to its edge due to the rotation of the central axis, forming a current potential. However, unlike ordinary rotational electrophoresis, the object surface is not immersed in the liquid as a whole. Instead, the liquid is projected onto the surface through the working electrode 1, resulting in only a thin liquid layer (i.e., the edge of the liquid layer) on the object surface. The thickness of this liquid layer is on the micrometer to millimeter scale. Thus, the longitudinal movement of the electron cloud is confined within the liquid layer. The black dashed line represents the cross-section of the electron cloud's trajectory. By confining the liquid within a thin layer on the micrometer to millimeter scale, the cross-sectional area of ​​the electron cloud's movement is reduced, and the resistance is increased. According to Ohm's law, the current potential signal is significantly enhanced, reducing the dependence on rotational speed and improving the signal-to-noise ratio and measurement accuracy.

[0039] like Figure 3 As shown, the present invention also provides a zeta potential measurement method applied to semiconductor material and process development, which is applied to the above-mentioned zeta potential measurement device for semiconductor material and process development, including: The sample to be tested, 5, is fixed on the sample rotation unit; The liquid delivery unit and sample rotation unit are activated to spray liquid onto the rotating sample surface through the working electrode, forming a liquid layer. The electrostatic potential generated in the liquid layer is detected by an electrode measurement unit; The zeta potential of the sample surface is calculated based on the current potential signal.

[0040] This invention provides a specific embodiment for detecting the zeta potential of a glass slide in two commonly used semiconductor solvents: propylene glycol methyl ether acetate and n-butanol, the chemical structures of which are shown in Table 1. Table 1 Chemical structural formulas

[0041] The two solvents mentioned above are commonly used in the semiconductor field. However, due to their chemical properties, existing instruments cannot measure the zeta potential of an object in these two solvents. Nevertheless, knowing the accurate zeta potential of an object in these two solvents would greatly facilitate and enhance the development of semiconductor materials. Many similar solvents exist in the semiconductor field. The two solvents selected in this invention are typical representatives of such solvents, intended to demonstrate the advantages and practicality of this invention in the semiconductor field.

[0042] Examples of applications for measuring the zeta potential of an object in propylene glycol methyl ether acetate or n-butanol include, but are not limited to: 1. Measuring the zeta potential of silicon wafers in solvents can predict the degree of adsorption of impurities in semiconductor materials (such as photoresists) on the surface of silicon wafers; 2. Measuring the zeta potential of the filter membrane in the solvent can predict the efficiency of the filtration step during the purification process of semiconductor materials (such as photoresist).

[0043] 3. Measuring the zeta potential between polymers can predict their physical stability. Polymers with low physical stability tend to aggregate and then settle, causing semiconductor materials (such as photoresists) to deteriorate and lose their effectiveness.

[0044] In this test, a glass slide was used, and the measurement steps were performed using the instrument described in this invention: 1. Install a small glass slide (25 mm in diameter and 2 mm in thickness) on the rotating rod 4. The installation method is to drip melted white sugar onto the back of the glass slide, then press the glass slide onto the rotating rod 4 and allow the sugar to cool down automatically. After cooling to room temperature, the sugar solidifies. The solidified sugar is insoluble in the organic solvent being tested. In this way, the glass slide is firmly installed and will not fall off during the test. 2. When using each solvent for measurement, adjust the sample rotation speed to 3000 rpm and the solvent outlet flow rate to 50 ml / min. After the measurement starts, wait 30 seconds until the current potential signal stabilizes. 3. Convert the current potential signal into a zeta potential.

[0045] The measurement results are as follows: 1. The zeta potential of glass in pure propylene glycol methyl ether acetate is -16mV.

[0046] 2. The zeta potential of glass in pure butanol is -110mV.

[0047] Embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0048] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0049] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0050] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0051] Contents not described in detail in this specification are prior art known to those skilled in the art. It is hereby indicated that the above description is intended to help those skilled in the art understand this invention, but does not limit the scope of protection of this invention. Any equivalent substitutions, modifications, improvements, or simplifications of the above descriptions that do not depart from the essential content of this invention fall within the scope of protection of this invention.

Claims

1. A zeta potential measurement device applied to semiconductor material and process development, characterized in that, include: Sample rotation unit, liquid delivery unit, electrode measurement unit, signal processing unit; The sample rotation unit is used to fix and rotate the sample to be tested; The liquid delivery unit includes a working electrode, a pump, and a liquid container. The working electrode is connected to the liquid container via the pump and is used to deliver the liquid to be tested to the surface of the sample to be tested to form a liquid layer. The electrode measurement unit includes a reference electrode, which is disposed on the periphery of the sample to be tested and is used to detect the current potential generated in the liquid layer due to the rotation of the sample. The electrode measurement unit is connected to the signal processing unit, which is used to calculate the zeta potential of the sample surface based on the current potential.

2. The zeta potential measuring device for semiconductor material and process development according to claim 1, characterized in that, The working electrode has a hollow internal structure, and its end is connected to the liquid container through a pipeline and a pump to spray the liquid to be tested onto the surface of the sample to be tested.

3. The zeta potential measuring device for semiconductor material and process development according to claim 1, characterized in that, The sample rotation unit is a rotating rod.

4. The zeta potential measuring device for semiconductor material and process development according to claim 1, characterized in that, An open container is provided on the lower side of the sample rotation unit to collect the test liquid that falls onto the sample.

5. The zeta potential measuring device for semiconductor material and process development according to claim 1, characterized in that, The electrode measurement unit also includes a voltmeter, and both the working electrode and the reference electrode are connected to the voltmeter.

6. The zeta potential measuring device for semiconductor material and process development according to claim 2, characterized in that, Both the reference electrode and the working electrode are made of silver or silver chloride, and their length is greater than 3 cm. The diameter of the reference electrode is 1-5 mm, and the diameter of the working electrode is 3-5 mm. The internal hollow structure of the working electrode is 1-2 mm thick. Both the reference electrode and the working electrode are provided with an insulating layer with a thickness of 1-2 mm on the outside, and 1-3 mm of silver or silver chloride material is exposed at both ends of the reference electrode and the working electrode.

7. The zeta potential measuring device for semiconductor material and process development according to claim 1, characterized in that, The top of the working electrode is 1-10 mm away from the test surface of the sample, and the exposed end of the reference electrode is used to contact the test liquid splashed out from the test surface of the sample.

8. The zeta potential measuring device for semiconductor material and process development according to claim 1, characterized in that, The working electrode ejects the liquid to be tested at a flow rate of 1-10 ml / s, and the rotating rod rotates at a speed of 1000-5000 rpm.

9. A method for measuring zeta potential applied to semiconductor material and process development, wherein the method is applied to the zeta potential measuring device for semiconductor material and process development as described in any one of claims 1-8, characterized in that, include: The sample to be tested is fixed on the sample rotation unit; The liquid delivery unit and sample rotation unit are activated to spray liquid onto the rotating sample surface through the working electrode, forming a liquid layer. The electrostatic potential generated in the liquid layer is detected by an electrode measurement unit; The zeta potential of the sample surface is calculated based on the current potential signal.

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