Electrochemical discharge / magnetic field synergistic auxiliary grinding and polishing method for high-purity semiconductor material

Abstract

The application discloses a kind of high-purity semiconductor material electrochemical discharge / magnetic field synergistic auxiliary grinding and polishing method, specific method is: grinding block as cathode;Auxiliary electrode as anode;Grinding fluid in grinding block is formed around gas film due to electrochemical reaction, gas film is broken down under the action of strong electric field, and then electrochemical discharge and discharge spark are generated;Discharge spark acts its nearby workpiece, and the physical and chemical properties of the workpiece subsurface layer material are significantly reduced, which can be efficiently ground by grinding block and produce grinding dust;In order to ensure the effect of subsequent magnetorheological polishing, high-temperature grinding fluid in the processing tank enters the cooling tank for cooling, and then is injected into the processing tank by the liquid supply pump;Magnetic field generating device generates adjustable magnetic field in size and direction, and under the action of magnetic field, magnetic sensitive abrasive particles in grinding fluid will be directional aggregation around grinding block to form chain-like flexible polishing layer, so as to polish the workpiece in the same process.The application can realize efficient, high-precision and low-damage grinding and polishing of high-purity semiconductor materials.

Description

Technical Field

[0001] This invention relates to the field of semiconductor polishing, and in particular to a method for polishing high-purity semiconductor materials using electrochemical discharge / magnetic field synergistic assistance. Background Technology

[0002] High-purity semiconductor materials such as single-crystal silicon, single-crystal silicon carbide, and gallium nitride, with their excellent properties of high hardness, high melting point, low loss, and poor electrical conductivity, have become key substrates for the fabrication of core micro-parts such as micro-sensors, micro-optical components, and semiconductor chips in cutting-edge fields such as aerospace, defense, microelectronics, and optoelectronics. These parts have stringent requirements for nanometer-level roughness, submicron-level dimensional accuracy, and non-destructive processing of the processed surface. However, the processing characteristics of hard and brittle high-purity semiconductor materials present a technical challenge that makes it difficult to balance efficiency, accuracy, and processing quality, posing a great challenge to processing technology.

[0003] To achieve high-precision, high-efficiency, and low-damage processing of hard and brittle semiconductor materials, our team applied for patents CN114434221A ("An Electrochemical Discharge-Assisted Micro-Grinding Device for Micro Parts of Hard and Brittle Materials") and CN114406375A ("An Electrochemical Discharge-Enabled Micro-Grinding Method for Micro Parts of Silicon-Based Materials"). This device and method achieve electrochemical discharge-assisted micro-grinding, rather than a simple superposition of electrochemical discharge machining and mechanical grinding. The electrochemical discharge process does not depend on the workpiece's conductivity. Through electrochemical discharge, the physical and chemical coupling modification of the workpiece's subsurface material is achieved, transforming the hard and brittle subsurface into a modified layer with significantly reduced mechanical properties. This subsurface modification effectively increases the critical depth of cut for the transition from brittle to ductile removal of hard and brittle materials. The modified layer is then removed using a micro-grinding tool, significantly weakening the mechanical grinding force between the tool and the workpiece and greatly improving material removal efficiency. This allows for stable ductile removal of the material, significantly reducing or even eliminating defects such as chipping, pitting, and cracking on the ground surface and subsurface. However, this technical solution still has the following problems: First, since the core of this technology is grinding, the subsurface material of the workpiece is ultimately removed by the micro-grinding tool. This inevitably results in surface defects such as micro-protrusions, micro-burrs, and grinding marks left by the mechanical grinding process. This prevents the achievement of high-precision, low-damage machining of hard and brittle semiconductor materials, thus limiting the improvement in part performance and requiring further improvement. Second, the micro-grinding tool is small, limiting the effective area of ​​the part processed in a single operation. After processing each workpiece, it is necessary to remove the processed workpiece and then fix the next workpiece to be processed, resulting in significant time waste and preventing uninterrupted machining of hard and brittle semiconductor materials. This also requires further improvement. Third, this method uses integrated grinding and polishing composite processing, completed simultaneously in the same step, rather than a simple superposition of grinding and polishing processes. Given the above problems with existing processes, it is urgent to develop a new processing method to overcome the bottleneck of high-efficiency, high-precision, and low-damage machining technology for micro-parts made of hard and brittle materials. Summary of the Invention

[0004] To overcome the shortcomings of existing processing methods, this invention provides a high-purity semiconductor material electrochemical discharge / magnetic field synergistic assisted polishing method. Its main features are: using electrochemical technology, the grinding block on a grinding wheel is used to electrochemically discharge and energize the area to be processed of the semiconductor material workpiece. This causes the subsurface material of the workpiece within the discharge area to transform into a modified layer with significantly reduced physical and mechanical properties under the coupled effect of physical and chemical modification. The modified layer is then rapidly and efficiently removed using the grinding block. Finally, magnetorheological technology is employed, where, under the action of a controllable magnetic field, magnetically sensitive abrasive particles in the grinding fluid will directionally aggregate around the grinding block to form a chain-like flexible polishing layer, thereby achieving polishing of the workpiece.

[0005] To achieve the above objectives, the technical solution adopted in this invention comprises the following steps: Step 1, electrochemical discharge: the grinding block serves as the cathode; the auxiliary electrode serves as the anode; the grinding block and the auxiliary electrode are immersed in the grinding fluid, forming a closed circuit; when the current from the pulsed DC power supply passes through the closed circuit, the H in the grinding fluid... + Electrons are generated from the cathode to produce hydrogen bubbles, which are distributed around the grinding block. Multiple hydrogen bubbles converge and merge to form a gas film; simultaneously, OH- in the grinding fluid... - Oxygen is generated by the loss of electrons at the anode. The auxiliary electrode is 10 to 100 times the size of the grinding block, which is insufficient to form an oxygen film. The gas film is broken down under the action of a strong electric field, resulting in electrochemical discharge and the generation of discharge sparks. Step two: Electrochemical discharge produces ablation and physical modification: The discharge spark directly melts or even vaporizes the surface material of the nearby workpiece. After the pulsed DC power supply is cut off, the melted or vaporized surface material of the workpiece is splashed out by the rapid cooling impact of the grinding fluid and forms ablation products. Ablation pits and recast layers are formed on the surface of the workpiece. Under the action of the discharge spark, the workpiece... The subsurface material is softened by high temperature to form a heat-affected layer, meaning the workpiece subsurface material is physically modified while the workpiece substrate remains unaffected. Electrochemical discharge produces chemical modification: simultaneously, the workpiece material temperature near the discharge spark rises, enabling it to react chemically with the grinding fluid and form chemical products, thus chemically modifying the workpiece subsurface material. Step three: High-efficiency mechanical grinding: the recast layer, the physically modified heat-affected layer, and the chemically modified chemical products are collectively referred to as the modified layer of the workpiece. Its physical and mechanical properties are significantly reduced, allowing it to be quickly and efficiently removed by the grinding block, producing grinding debris. The formation of this process can increase the critical depth of the brittle-plastic transition in hard and brittle materials, allowing the grinding block to act more concentratedly on the modified layer. This weakens the direct mechanical force between the grinding block and the workpiece, reducing chipping, pitting, breakage, and microcracks on the workpiece surface. Step four: Magnetorheological high-precision polishing: During the electrochemical discharge process, the temperature of the grinding fluid in the processing tank will rise significantly, severely reducing the effect of subsequent magnetorheological polishing. Therefore, a cooling tank is needed to cool the grinding fluid. The high-temperature grinding fluid in the processing tank enters the cooling tank through the outlet pipe for cooling. The supply pump delivers the cooled grinding fluid through... The liquid is injected into the processing tank through the inlet pipe; after the AC power supply powers the magnetic field generating device, an adjustable magnetic field of magnitude and direction is generated around the grinding block; under the action of the magnetic field, the magnetic abrasive particles in the grinding fluid will be oriented and aggregated around the grinding block to form a chain-like flexible polishing layer, thereby polishing the surface defects such as micro-protrusions, micro-burrs and grinding marks left by mechanical grinding of the workpiece in the same process, thus achieving high-efficiency, high-precision and low-damage grinding and polishing of hard and brittle material workpieces; Step 5: Repeat steps one to four, the grinding wheel rotates along the preset path on the surface of the workpiece, which can grind and polish the surface of the workpiece.

[0006] The mass fraction range of each component in the grinding fluid is as follows: iron powder 2.7%–4%, free diamond abrasive grains 6.7%–10%, starch 28.8%–35%, chemical additives 0.7%–2%, NaOH 6.4%–10%, and deionized water 50%–70%.

[0007] The pulse voltage of the pulsed DC power supply is in the range of 40 to 60 V, the pulse frequency is 500 to 1000 Hz, and the duty cycle is 50% to 60%.

[0008] The grinding wheel (3) has a rotational speed range of 1000 to 2000 r / min, the turntable (7) has a rotational speed range of 70 to 90 r / min, and the grinding wheel (3) has a feed speed range of 0.1 to 0.4 μm / s.

[0009] The magnetic field generating device produces a magnetic induction intensity of 10–150 mT.

[0010] The turntable and the grinding wheel rotate simultaneously and work together on the workpiece. After one workpiece is finished, the grinding wheel does not need to stop working, but continues to process the next workpiece to be processed on the turntable, thereby further improving the workpiece processing efficiency.

[0011] The following beneficial effects can be obtained by implementing the electrochemical discharge / magnetic field synergistic assisted polishing method for high-purity semiconductor materials described in this invention.

[0012] ① Achieve integrated grinding and polishing in the same process. Integrate electrochemical discharge and magnetic field synergistic polishing technology. Electrochemical discharge increases the critical depth of cut for the transition from brittle to ductile removal of hard and brittle materials. Consolidated diamond abrasives quickly and efficiently remove the modified layer. Magnetic field controls free diamond abrasives to form a chain-like flexible polishing layer, completing high-precision polishing. Defect removal and polishing are achieved in the same process, rather than simply superimposing multiple processes, achieving high efficiency, high precision, and low damage.

[0013] ② Flexible polishing with high precision and low damage. The chain-like flexible polishing layer formed by the magnetic particles in the grinding fluid under the action of a magnetic field is a flexible contact process that removes surface defects such as micro-protrusions, micro-burrs, and grinding marks left by mechanical grinding. It effectively polishes the surface defects of the workpiece in the same process, thereby realizing efficient, high-precision, and low-damage grinding and polishing of high-purity semiconductor materials.

[0014] ③ Temperature control ensures the overall performance of the polishing medium. Equipped with a grinding fluid circulation cooling system, the temperature of the grinding fluid in the processing tank is precisely controlled at 20-25℃, solving the problem of attenuation of magnetic sensitivity and conductivity caused by the temperature rise of the grinding fluid during electrochemical discharge, and ensuring the stability of the grinding fluid performance.

[0015] ④ The magnetic field is highly adjustable and adaptable. The magnetic field generator is powered by AC power and can flexibly adjust the magnitude and direction of the magnetic field, thereby changing the shape and hardness of the chain-like flexible polishing layer. It is suitable for hard and brittle semiconductor materials with different hardness, such as silicon-based and silicon carbide-based materials, as well as grinding and polishing processes with different surface precision requirements, thus improving the versatility and process adaptability of the device.

[0016] ⑤ Rapid chip removal. The magnetic field generator is powered by AC power and the magnitude and direction of the magnetic field can be flexibly adjusted. The magnetic particles in the grinding fluid form a chain-like flexible polishing layer under the action of the magnetic field. The polishing layer and the equipped grinding fluid circulation cooling system work together to accelerate the removal of grinding chips. Attached Figure Description

[0017] Figure 1 This is a schematic diagram illustrating the processing principle of an electrochemical discharge / magnetic field synergistic assisted polishing device for high-purity semiconductor materials.

[0018] Figure 2 This is a schematic diagram of an electrochemical discharge / magnetic field synergistic assisted polishing device for high-purity semiconductor materials according to the present invention. Figure 3 This is a three-dimensional assembly diagram of an electrochemical discharge / magnetic field synergistic assisted polishing device for high-purity semiconductor materials according to the present invention.

[0019] Figure 4 This is a structural diagram of the grinding wheel and rotary table of an electrochemical discharge / magnetic field synergistic assisted grinding and polishing device for high-purity semiconductor materials according to the present invention.

[0020] Figure 5 for Figure 2 A magnified view of a portion of the grinding wheel.

[0021] Figure reference numerals: 1. Grinding wheel spindle; 2. Spindle sleeve; 3. Grinding wheel; 3-1. Grinding wheel disc; 3-1-1. Brush; 3-1-2. Slip ring; 3-1-3. Wire; 3-2. Grinding block; 3-2-1. Adhesive; 3-2-2. Bonded diamond abrasive grains; 4. Magnetic field generating device; 5. Workpiece; 5-1. Workpiece substrate; 5-2. Surface material melting or even vaporization; 5-3. Ablation products; 5-4. Ablation pits; 5-5. Recast layer; 5-6 5-7. Heat-affected layer; 5-8. Chemical products; 5-9. Modified layer; 5-10. Grinding debris; 5-11. Surface defects; 6. Suction cup; 7. Turntable; 8. Pulsed DC power supply; 9. Auxiliary electrode; 10. Liquid inlet pipe; 11. Liquid supply pump; 12. Grinding fluid; 12-1. Iron powder; 12-2. Free diamond abrasive grains; 12-3. Starch; 12-4. Chain-like flexible polishing layer; 13. Cooling tank; 14. Liquid outlet pipe; 15. Machining tank; 16. AC power supply. Detailed Implementation

[0022] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific examples.

[0023] like Figure 2 As shown, a high-purity semiconductor material electrochemical discharge / magnetic field synergistic assisted polishing method includes the following steps.

[0024] Step 1, Electrochemical Discharge: The grinding block (3-2) serves as the cathode; the auxiliary electrode (9) serves as the anode; the grinding block (3-2) and the auxiliary electrode (9) are immersed in the grinding fluid (12) to form a closed circuit; the grinding fluid (12) is composed of 3.5% iron powder (12-1), 8.5% free diamond abrasive grains (12-2), 29% starch (12-3), 1% chemical additives, 6.5% NaOH and 51.5% deionized water by mass fraction, and has conductivity; the pulse voltage range of the pulse DC power supply is 50 V, the pulse frequency is 800 Hz and the duty cycle is 50%; when the current of the pulse DC power supply (8) passes through the closed circuit, the H in the grinding fluid (12) + Electrons are generated from the cathode to produce hydrogen bubbles, which are distributed around the grinding block (3-2). Multiple hydrogen bubbles converge and merge to form a gas film (18); at the same time, OH in the grinding fluid (12) - Oxygen is generated by losing electrons at the anode. The size of the auxiliary electrode (9) is 30 times that of the grinding block (3-2), which is insufficient to form an oxygen film. The gas film (18) is broken down under the action of a strong electric field, which leads to electrochemical discharge and generates discharge sparks (17).

[0025] Step 2: Electrochemical discharge generates ablation and physical modification: The discharge spark (17) directly melts or even vaporizes the surface material of the workpiece (5) in its vicinity (5-2). After the pulsed DC power supply (8) is de-energized, the surface material of the melted or vaporized workpiece (5) is splashed out by the grinding fluid (12) and forms ablation products (5-3). Ablation pits (5-4) and recast layers (5-5) are formed on the surface of the workpiece (5). Under the action of the discharge spark (17), the subsurface material of the workpiece (5) is softened by high temperature to form a heat-affected layer (5-6), that is, the subsurface material of the workpiece (5) is physically modified, and the workpiece substrate (5-1) is not affected. Electrochemical discharge generates chemical modification: At the same time, the material temperature of the workpiece (5) near the discharge spark (17) increases, and it can react chemically with the grinding fluid (12) to form chemical products (5-7), that is, the subsurface material of the workpiece (5) is chemically modified.

[0026] Step 3, Mechanical high-efficiency grinding: The recast layer (5-5), the physically modified heat-affected layer (5-6), and the chemically modified chemical product (5-7) are collectively referred to as the modified layer (5-8) of the workpiece (5). Its physical and mechanical properties are significantly reduced, and it can be quickly and efficiently ground away by the grinding block (3-2) to produce grinding debris (5-9). The formation of the modified layer (5-8) can increase the critical depth of the brittle-plastic transition of hard and brittle materials. The grinding block (3-2) acts more concentratedly on the modified layer (5-8), thereby weakening the direct mechanical force between the grinding block (3-2) and the workpiece (5) and reducing the chipping, pitting, breakage and microcracks on the surface of the workpiece (5).

[0027] Step 4, Magnetorheological High-Precision Polishing: During the electrochemical discharge process, the temperature of the grinding fluid (12) in the processing tank (15) will rise significantly, which will seriously reduce the effect of subsequent magnetorheological polishing. Therefore, a cooling tank (13) is needed to cool the grinding fluid (12). The high-temperature grinding fluid (12) in the processing tank (15) enters the cooling tank (13) through the outlet pipe (14) for cooling. The liquid supply pump (11) injects the cooled grinding fluid (12) into the processing tank (15) through the inlet pipe (10). After the AC power supply (16) supplies power to the magnetic field generating device (4), the intensity of the magnetic induction generated by the magnetic field generating device is 150. mT can generate a magnetic field with adjustable size and direction around the grinding block (3-2); under the action of the magnetic field, the magnetic sensitive abrasive particles in the grinding fluid (12) will be oriented to gather around the grinding block (3-2) to form a chain-like flexible polishing layer (12-4), thereby polishing the surface defects (5-10) such as micro-protrusions, micro-burrs and grinding marks left by mechanical grinding of the workpiece (5) in the same process, thereby achieving high-efficiency, high-precision and low-damage grinding and polishing of hard and brittle material workpiece (5); the grinding wheel speed range is 1500 r / min, the turntable speed range is 70 r / min, the grinding wheel feed speed range is 0.2 μm / s; the turntable (7) and the grinding wheel (3) rotate at the same time and act together on the workpiece (5). After a workpiece (5) is processed, the grinding wheel (3) does not need to stop working, but continuously processes the next workpiece (5) to be processed on the turntable (7), thereby further improving the workpiece processing efficiency.

[0028] Step 5: Repeat steps 1 to 4. The grinding wheel (3) rotates along the preset path on the surface of the workpiece (5) to polish the surface of the workpiece (5).

[0029] The specific descriptions of the above examples are only used to illustrate the present invention more clearly and are not intended to limit the scope of the present invention. Any equivalent substitutions, modifications, etc., made within the scope of the disclosure of the present invention are included within the protection scope of the present invention.

Claims

1. A high-purity semiconductor material electrochemical discharge / magnetic field synergistic assisted polishing method, wherein the electrochemical discharge / magnetic field synergistic assisted polishing device required by the method comprises: a grinding wheel spindle (1), a spindle sleeve (2), a grinding wheel (3), a magnetic field generator (4), a workpiece (5), a suction cup (6), a turntable (7), a pulsed DC power supply (8), an auxiliary electrode (9), a liquid inlet pipe (10), a liquid supply pump (11), a grinding fluid (12), a cooling tank (13), and a liquid outlet pipe. (14) Machining tank (15) AC power supply (16); The grinding block (3-2) is composed of an electroplated layer (3-2-1) and bonded diamond abrasive grains (3-2-2). The grinding block (3-2) is connected to the wire (3-1-3), which is connected to the slip ring (3-1-2). The slip ring (3-1-2) is matched with the brush (3-1-1). The brush (3-1-1) is connected to the negative terminal of the pulse DC power supply (8), so that the grinding block (3-2) is in the electric field. In the chemical discharge process, it forms the cathode; the auxiliary electrode (9) is made of inert conductive graphite material and is connected to the positive terminal of the pulsed DC power supply (8), forming the anode in the electrochemical discharge process; the grinding block (3-2) and the auxiliary electrode (9) are immersed in the grinding fluid (12) to form a closed circuit, and the size of the auxiliary electrode (9) is 10 to 100 times that of the grinding block (3-2); the workpiece (5) is a hard and brittle semiconductor material, and its surface needs to be polished with high quality, high efficiency and low damage; the grinding fluid (12) is composed of iron powder (12-1), free diamond abrasive grains (12-2), starch (12-3), chemical additives, NaOH and deionized water, and has conductivity; the grinding fluid (12) enters the cooling tank (13) through the outlet pipe (14), and the cooled grinding fluid (12) is injected into the processing tank (15) through the inlet pipe (10); the AC power supply (16) supplies power to the magnetic field generating device (4) to generate a magnetic field around the grinding block (3-2); Its features are: The processing procedure is as follows: Step 1, Electrochemical Discharge: The grinding block (3-2) serves as the cathode; the auxiliary electrode (9) serves as the anode; the grinding block (3-2) and the auxiliary electrode (9) are immersed in the grinding fluid (12), forming a closed circuit; when the current from the pulsed DC power supply (8) passes through the closed circuit, the H in the grinding fluid (12) + Electrons are generated from the cathode to produce hydrogen bubbles, which are distributed around the grinding block (3-2). Multiple hydrogen bubbles converge and merge to form a gas film (18); at the same time, OH in the grinding fluid (12) - Oxygen is generated by losing electrons at the anode. The size of the auxiliary electrode (9) is 10 to 100 times that of the grinding block (3-2), which is insufficient to form an oxygen film. The gas film (18) is broken down under the action of a strong electric field, which leads to electrochemical discharge and generates discharge sparks (17). Step 2: Electrochemical discharge generates ablation and physical modification: The discharge spark (17) directly melts or even vaporizes the surface material of the nearby workpiece (5) (5-2). After the pulsed DC power supply (8) is cut off, the melted or vaporized surface material of the workpiece (5) is splashed out by the grinding fluid (12) and forms ablation products (5-3). Ablation pits (5-4) and recast layer (5-5) are formed on the surface of the workpiece (5). Under the action of the discharge spark (17), the subsurface material of the workpiece (5) is softened by high temperature to form a heat-affected layer (5-6). That is, the subsurface material of the workpiece (5) is physically modified, and the workpiece substrate (5-1) is not affected. Electrochemical discharge produces chemical modification: At the same time, the material temperature of the workpiece (5) near the discharge spark (17) increases, which can react chemically with the grinding fluid (12) and form chemical products (5-7), that is, the subsurface material of the workpiece (5) is chemically modified. Step 3, Mechanical high-efficiency grinding: The recast layer (5-5), the physically modified heat-affected layer (5-6), and the chemically modified chemical product (5-7) are collectively referred to as the modified layer (5-8) of the workpiece (5). Its physical and mechanical properties are significantly reduced, and it can be quickly and efficiently ground away by the grinding block (3-2) to produce grinding debris (5-9). The formation of the modified layer (5-8) can increase the critical depth of the brittle-plastic transition of hard and brittle materials. The grinding block (3-2) acts more concentratedly on the modified layer (5-8), thereby weakening the direct mechanical force between the grinding block (3-2) and the workpiece (5) and reducing the chipping, pitting, breakage and microcracks on the surface of the workpiece (5). Step 4, Magnetorheological High-Precision Polishing: During the electrochemical discharge process, the temperature of the grinding fluid (12) in the processing tank (15) will rise significantly, which will severely reduce the effect of subsequent magnetorheological polishing. Therefore, a cooling tank (13) is needed to cool the grinding fluid (12). The high-temperature grinding fluid (12) in the processing tank (15) enters the cooling tank (13) through the outlet pipe (14) for cooling. The liquid supply pump (11) injects the cooled grinding fluid (12) into the processing tank (15) through the inlet pipe (10). After the current power supply (16) supplies power to the magnetic field generating device (4), an adjustable magnetic field of magnitude and direction can be generated around the grinding block (3-2). Under the action of the magnetic field, the magnetic sensitive abrasive particles in the grinding fluid (12) will be oriented and aggregated around the grinding block (3-2) to form a chain-like flexible polishing layer (12-4), thereby polishing the surface defects (5-10) such as micro-protrusions, micro-burrs and grinding marks left by mechanical grinding of the workpiece (5) in the same process, thereby achieving high-efficiency, high-precision and low-damage grinding and polishing of the hard and brittle material workpiece (5). Step 5: Repeat steps 1 to 4. The grinding wheel (3) rotates along the preset path on the surface of the workpiece (5) to polish the surface of the workpiece (5).

2. The electrochemical discharge / magnetic field synergistic assisted polishing method for high-purity semiconductor materials according to claim 1, characterized in that: The mass fraction range of each component in the grinding fluid (12) is as follows: iron powder (12-1) 2.7%–4%, free diamond abrasive (12-2) 6.7%–10%, starch (12-3) 28.8%–35%, chemical additives 0.7%–2%, NaOH 6.4%–10%, and deionized water 50%–70%.

3. The electrochemical discharge / magnetic field synergistic assisted polishing method for high-purity semiconductor materials according to claim 1, characterized in that... The pulse voltage of the pulse DC power supply (8) is 40 to 60 V, the pulse frequency is 500 to 1000 Hz, and the duty cycle is 50% to 60%.

4. The electrochemical discharge / magnetic field synergistic assisted polishing method for high-purity semiconductor materials according to claim 1, characterized in that... The grinding wheel (3) has a rotational speed range of 1000 to 2000 r / min, the turntable (7) has a rotational speed range of 70 to 90 r / min, and the grinding wheel (3) has a feed speed range of 0.1 to 0.4 μm / s.

5. The electrochemical discharge / magnetic field synergistic assisted polishing method for high-purity semiconductor materials according to claim 1, characterized in that: The magnetic field generating device (4) generates a magnetic field with an intensity of 10 to 150 mT.

6. The electrochemical discharge / magnetic field synergistic assisted polishing method for high-purity semiconductor materials according to claim 1, characterized in that: The turntable (7) and the grinding wheel (3) rotate simultaneously and work together on the workpiece (5). After a workpiece (5) is processed, the grinding wheel (3) does not need to stop working, but continues to process the next workpiece (5) to be processed on the turntable (7) without interruption, thereby further improving the workpiece processing efficiency.

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