Electrochemical mechanical thinning method and apparatus for large diameter semiconductor wafers

Abstract

To provide an electrochemical mechanical thinning processing method of a large diameter semiconductor wafer, for thinning the large diameter semiconductor wafer by modification of positive electrode oxidation and mechanical grinding, and provide a device.SOLUTION: In an electrochemical mechanical thinning processing device of a large diameter semiconductor wafer 7, comprising: a grinding tool system 1; a wafer fixing device 9; and a dressing device (a grinding dresser 11) of a grinding 3, the grinding tool system contains a grinding board 2 and the cup type grinding 3. The cup type grinding is fixed to the grinding board, and the grinding board is a negative electrode, and the semiconductor wafer is a positive electrode. In a thinning step, both of the negative electrode and the positive electrode are immersed into an electrolyte 5, and the semiconductor wafer modifies and softens a front surface by an action of an external magnetic field, and removes an oxidation layer and an intermediate generation material to be modified by the grinding, and thus, thinning processing of the semiconductor wafer is realized by a composite action of a plurality of energy fields such as electric, chemical, mechanical, and power fields.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to the technical field of semiconductor wafer processing, and more specifically to a thinning apparatus and processing method applicable to large-diameter semiconductor wafers of 4 inches or more, which can be applied to thinning semiconductor wafers with low damage and high efficiency. [Background technology]

[0002] With the development of electronic information technology, silicon (Si)-based semiconductor devices are gradually reaching their physical limits. Wide bandgap semiconductors, such as silicon carbide (SiC), gallium nitride (GaN) and diamond, can operate reliably in high temperature, high frequency and high power environments, and are essential materials for the manufacture of low-loss, high frequency and high energy power devices. In order to meet the requirements for the use of high performance power devices, the manufacture of wafers requires processes such as thinning, double-sided polishing and chemical mechanical polishing (CMP) after slicing, which finally results in an extremely smooth and damage-free surface. Among these processes, grinding thinning has the largest removal amount and has an important impact on the wafer thickness, dimensional accuracy, geometric tolerance, surface roughness and subsurface damage.

[0003] These wide band gap semiconductor materials are typical high hardness and brittleness materials, for example, silicon carbide has a hardness lower than that of diamond, and has extremely high chemical stability, and hardly reacts with strong acid or strong alkali, so that its processing is very difficult. At present, the thinning process of silicon carbide wafer is mainly performed by mechanical processing using diamond grinding wheel. However, the simple mechanical thinning process is inefficient and the grinding wheel wears a lot, so the processing cost is high, and the processing principle of using hardness difference inevitably introduces a deep damage layer on the surface of the workpiece, which deteriorates the electrical properties of the workpiece, and the subsequent polishing removal amount for removing the damage layer is also greatly increased. Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention aims to provide a method and apparatus for electrochemical mechanical thinning of large diameter semiconductor wafers, which reduces wear of the grinding wheel, reduces the damaged layer of the wafer, and significantly reduces the amount of subsequent polishing removal. [Means for solving the problem]

[0005] In order to achieve the above object, an electrochemical mechanical thinning apparatus for large diameter semiconductor wafers according to the present invention comprises a grinding tool system, the grinding tool system is attached to a lifting device, a wafer fixing device is provided below the grinding tool system, the grinding tool system includes a grinding base and a grinding wheel, the grinding wheel is fixed to a lower end of the grinding base, the grinding base is connected to a cathode conductive slip ring, and an anode conductive slip ring is attached to the wafer clamping device, and the anode conductive slip ring contacts the semiconductor wafer being thinned during thinning; The outer ring of the cathode conductive slip ring is connected to the negative pole of a power supply device, and the outer ring of the anode conductive slip ring is connected to the positive pole of the power supply device, and during the thinning process, the grinding base and the semiconductor wafer to be thinned are both in contact with an electrolyte.

[0006] Furthermore, the semiconductor wafer may be fixed to the wafer fixing device by a vacuum suction method or an adhesive method.

[0007] Furthermore, a notch may be provided in an upper portion of the wafer fixing device, a vacuum suction fixing plate may be provided in the notch, a through hole may be provided in a bottom portion of the notch, and the through hole may be connected to a vacuum pump by a tube and a swivel joint, and the vacuum suction fixing plate may be used to fix the semiconductor wafer being thinned.

[0008] Furthermore, the power supply device may be an electrochemical workstation, and the electrochemical workstation may have a counter electrode connected to the outer ring of the cathode conductive slip ring and a working electrode connected to the outer ring of the anode conductive slip ring.

[0009] Additionally, the wafer clamping device may be mounted within an electrolyte tank for holding the electrolyte.

[0010] Furthermore, a dressing device for dressing the grinding wheel may be provided below the grinding tool system, the dressing device may be provided within the electrolyte tank, a slide block may be fixed to a lower end of the electrolyte tank, and the slide block may be slidably connected to a slide rail attached to a bottom plate.

[0011] Furthermore, the outlet of the electrolyte tank may be connected to the input end of a peristaltic pump by piping, the output end of the peristaltic pump may be connected to the input end of an electrolyte filter by piping, and the output end of the electrolyte filter may be connected to the inlet of the electrolyte tank by piping.

[0012] Furthermore, a constant temperature water tank may be provided in a pipe between the output end of the electrolyte filter and the inlet of the electrolyte tank.

[0013] The electrochemical mechanical thinning method for large-diameter semiconductor wafers using the electrochemical mechanical thinning apparatus for large-diameter semiconductor wafers according to the present invention includes the steps of: Step S1 of cleaning and drying the semiconductor wafer; A step S2 of measuring a thickness H of the semiconductor wafer and determining a thinning removal amount Hh based on a target thickness h to be thinned; Step S3 of fixing the semiconductor wafer to the wafer fixing device; Step S4: moving the wafer fixture below the grinding tool system and moving the grinding tool system downward until the bottom of the grinding wheel contacts the surface of the semiconductor wafer; Step S5 of setting electrochemical reforming parameters by the power supply device; Step S6: setting a removal amount and a feed amount for the thinning process, and starting the driving motors of the grinding tool system and the wafer fixing device; Step S7 of starting the power supply device and applying a voltage / current; and step S8 of performing a thinning process, in which the semiconductor wafer is subjected to an anodizing reaction with an electrolyte due to the action of an electric field to produce an oxide on the surface of the semiconductor wafer, the oxide having a hardness lower than that of the base material of the semiconductor wafer, and the wafer is removed by relative movement between the grindstone and the semiconductor wafer until it is thinned to a target thickness h.

[0014] Furthermore, before step S5, a peristaltic pump is started to operate the electrolyte filter device, and if it is necessary to further control the temperature of the electrolyte, a thermostatic water bath may be operated to set the temperature. Effect of the Invention

[0015] Compared with the prior art, the present invention has at least the following beneficial technical effects:

[0016] 1) High thinning efficiency. The present invention can effectively modify and soften extremely hard semiconductor wafers by anodizing the semiconductor wafers during thinning, and also remove the wafer surface including the wafer surface base material, the oxidized modified layer, and intermediate products by using a grindstone. Since anodizing and mechanical grinding are performed simultaneously, the wafer can be efficiently thinned, and has the advantage of significantly reducing the surface roughness and damaged layer after thinning.

[0017] 2) Wear of the grinding wheel is small, reducing costs. The surface hardness of the wafer can be reduced through electrochemical modification, which can effectively reduce the grinding force of the grinding wheel and reduce the wear of the grinding wheel, thereby reducing the processing cost.

[0018] 3) There is no need to add strong acids, strong alkalis or strong oxidizing agents, making it green and environmentally friendly. During the processing, the electrons and holes inside the wafer are separated by the action of an external electric field, and the holes move to the wafer surface and the electrolyte interface, where the holes have strong oxidizing properties and react with the water molecules in the electrolyte to achieve anodizing modification. There is no need to add strong acids, strong alkalis or strong oxidizing agents, and green wafer manufacturing can be achieved.

[0019] 4) The structure of the processing device is simple, and the processing method is easy to implement. The processing parameters of this processing device are the grinding feed rate, the rotational speed of the grinding tool, the rotational speed of the wafer, the rotational speed of the dressing device, and the type and concentration of the electrolyte. In addition, the potential difference between the wafer and the counter electrode and the current density are all adjusted according to the actual processing conditions, thereby achieving the optimal processing effect.

[0020] In addition, in order to ensure the processing effect, the cup-shaped diamond grinding wheel needs to be dressed in a timely manner, and the dressing device is moved horizontally to the bottom of the grinding tool system to contact the upper surface of the dresser, and the grinding tool system and the dressing device are rotated to generate relative movement, thereby realizing the online dressing of the cup-shaped diamond grinding wheel.

[0021] This method uses the methods of mechanical thinning and electrochemical anodizing modification, with the grinding substrate as the cathode and the semiconductor wafer as the anode. During processing, both the cathode and the anode are immersed in electrolyte. Under the action of an external electric field, the semiconductor wafer undergoes an anodizing reaction with the electrolyte to modify and soften the surface, while simultaneously removing the oxide layer and intermediate products generated by the diamond grinding wheel, and the thinning process of the semiconductor wafer is realized through the combined action of multiple energy fields including electricity, chemicals, mechanics and force. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 is a schematic diagram of an electrochemical mechanical thinning apparatus for semiconductor wafers according to the present invention. [Diagram 2] FIG. 2 is a principle diagram of the electrochemical mechanical thinning method for semiconductor wafers according to the present invention. [Diagram 3] FIG. 3 is a three-dimensional view of an electrochemical mechanical thinning apparatus for semiconductor wafers according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] In order to make the objectives and technical solutions of the present invention clearer and easier to understand, the present invention will be described in more detail below with reference to the drawings and examples. However, the specific examples described herein are merely for the purpose of interpreting the present invention and are not intended to limit the present invention.

[0024] The electrochemical mechanical thinning processing apparatus for semiconductor wafers according to the present invention includes a grinding tool system 1, an electrolyte tank 4, a cathode conductive slip ring 6, a wafer fixing device 9, an anode conductive slip ring 10, a thermostatic water bath 12, an electrolyte filter 13, a peristaltic pump 14, an electrochemical workstation 15, an electric lift plate 21, a bottom plate 22, and a dressing device for dressing the grinding wheel 3. The dressing device is a dresser 11.

[0025] The grinding tool system 1 is fixed to an electric lift plate 21, and the feed amount during the thinning process of the semiconductor wafer can be adjusted.

[0026] The grinding tool system 1 includes a hollow grinding spindle, a grinding base 2, and a grinding wheel 3, the grinding hollow spindle passes through the grinding tool system and is rotatable by being driven by a first servo motor 20 via a belt and a pulley. The grinding wheel 3 is fixed to the lower end of the grinding base 2, and the diameter of the lower end surface of the grinding wheel 3 is larger than the diameter of the semiconductor wafer 7, the grinding base 2 serves as the cathode, and the processed semiconductor wafer 7 serves as the anode. During the processing, both the cathode and the anode are immersed in an electrolyte 5 such as NaCl, KCl, NaNO3, KNO3, or NaCO3.

[0027] The grinding base 2 is made of metal and fixed to the bottom of the grinding hollow spindle as a cathode plate, and is connected to the output shaft of the first servo motor 20 via the grinding hollow spindle by a pulley and a belt, a cathode conductive slip ring 6 is provided on the outside of the hollow spindle, and a wire is provided inside the hollow spindle, one end of which is connected to the grinding base 2 and the other end of which is connected to the inner ring of the cathode conductive slip ring 6. The outer ring of the cathode conductive slip ring 6 is connected by a wire to the counter electrode of the electrochemical workstation 15 or the negative electrode of a DC power source.

[0028] A negative potential applied from the outside can reach the grinding base 2 by passing through the outer ring lead and inner ring lead of the cathode conductive slip ring 6 located above the grinding base 2, and a positive potential applied from the outside can pass through the outer ring lead and inner ring lead of the anode conductive slip ring 10 located below the wafer fixing device 9, connect to the vacuum suction fixing plate 8, and finally be conducted to the semiconductor wafer 7. A potential difference is formed by applying a negative potential to the grinding base 2 (cathode plate) and a positive potential to the semiconductor wafer 7.

[0029] The grinding wheel 3 is fixed to the lower end of the grinding base 2 and driven by a digital control system, so that the grinding wheel 3 comes into contact with the semiconductor wafer 7 to generate relative movement. The grinding wheel 3, which is a grinding tool, is preferably a cup-shaped diamond grinding wheel, but is not limited thereto. Grinding wheels with different properties and hardness, such as alumina and cerium oxide, may also be selected to remove the surface of the semiconductor wafer and achieve wafer thinning. The surface of the wafer includes the wafer surface substrate, the oxidation modification layer, and the intermediate product.

[0030] Two slide rails are fixed to the bottom plate 22, a slide block is slidably attached to the slide rails, an electrolyte tank 4 is fixed to the slide block, the upper parts of the wafer fixing device 9 and the dresser 11 are placed in the electrolyte tank 4, and during thinning, the surfaces of the grinding base 2 (cathode plate) and the semiconductor wafer 7 are both immersed in the electrolyte 5, the counter electrode of the electrochemical workstation 15 is connected to the outer ring of the conductive slip ring 6 by a wire, and the working electrode is connected to the outer ring of the conductive slip ring 10 by a wire, and the electrochemical workstation 15, the semiconductor wafer 7, the electrolyte 5, and the grinding base 2 (cathode plate) form an electric circuit.

[0031] The electrochemical workstation 15 may be replaced by a power supply, in which case the power supply has its negative pole connected to the outer ring of the conductive slip ring 6 and its positive pole connected to the outer ring of the conductive slip ring 10.

[0032] The electrolytic solution 5 may be supplied by flowing through a pipe, and it is sufficient that both the semiconductor wafer 7 and the grinding base 2 are in contact with the electrolytic solution.

[0033] An electrolyte 5 is stored in an electrolyte tank 4, and during the polishing process, the grinding base 2, diamond grinding wheel 3, and semiconductor wafer 7 are immersed in the electrolyte, and the electrolyte 5 serves as an anodizing medium and provides a liquid environment for thinning and grinding, and the relative movement between the grinding tool system 1 and the semiconductor wafer 7 allows impurities such as chips caused by polishing to move away from the surface of the semiconductor wafer 7 along with the flow of the electrolyte, preventing scratches on the wafer surface and ensuring the quality of the machined surface. A method of flowing and circulating the electrolyte at this point may be used.

[0034] A semiconductor wafer 7 is fixed to the upper surface of a wafer fixing device 9 by vacuum suction or adhesion, and is driven by a second servo motor, which is connected to the main shaft of the wafer fixing device by a pulley, and the semiconductor wafer 7 rotates in the axial direction together with the wafer fixing device 9. A grinding wheel 3 is fixed to a grinding base 2 (the grinding base in this invention is a metal material), and is driven to come into contact with the semiconductor wafer, generating relative movement.

[0035] When fixing is performed by vacuum suction, a notch is provided on the top of the wafer fixing device 9, the middle part of the notch is the vacuum suction fixing plate 8, and a circular through-hole is provided at the bottom of the notch, which is connected to a vacuum pump by a tube and a swivel joint. The semiconductor wafer 7 is placed on the upper end of the vacuum suction fixing plate 8, and when the vacuum pump is operated, the semiconductor wafer 7 can be fixed by vacuum suction.

[0036] The vacuum suction fixing plate 8 is made of a conductive material and has conductivity. Under vacuum suction fixing conditions, the semiconductor wafer 7 is in close contact with the vacuum suction fixing plate 8 and is electrically conductive. The hollow shaft of the wafer fixing device 9 is provided with a conductive slip ring 10 on the outside and a wire on the inside. One end of the wire is connected to the vacuum suction fixing plate 8 and the other end is connected to the inner ring of the conductive slip ring 10. The outer ring of the conductive slip ring 10 is connected to the working electrode of the electrochemical workstation 15 or the positive pole of the DC power supply by a wire, thereby finally realizing the connection between the working electrode of the electrochemical workstation 15 and the semiconductor wafer 7.

[0037] Thermostatic water bath 12 is used to control the temperature of electrolyte 5, and is connected to the inlet of electrolyte tank 4 by one pipe and to the output end of electrolyte filter 13 by another pipe. The input end of electrolyte filter 13 is connected to the output end of peristaltic pump 14, and the input end of peristaltic pump 14 is connected to the outlet of electrolyte tank 4 by a pipe.

[0038] The electrolyte filter 13 filters out impurities such as chips generated during the thinning process. The peristaltic pump 14 filters the polishing residue in the electrolyte and circulates the electrolyte, preventing the polishing residue from scratching the wafer surface and enabling the electrolyte to be reused.

[0039] The peristaltic pump 14 provides power for the circulation of the electrolyte, and the circulation speed of the electrolyte can be adjusted.

[0040] The grinding wheel dresser 11 is located on the work table in the horizontal direction of the device and can move in the horizontal direction. When the grinding wheel dresser 11 rotates by driving the third servo motor and the screw drives the slide block to move the dresser 11 below the grinding tool system 1, relative movement occurs and the cup-shaped diamond grinding wheel 3 can be trimmed.

[0041] The grinding tool system 1 is located at the top of the thinning processing apparatus, and the wafer fixing device 9 and the dressing device 11 are installed in parallel at the bottom of the thinning processing apparatus and can move laterally, thereby enabling switching between wafer thinning processing and grinding tool dressing.

[0042] The semiconductor wafer 7 may be a silicon, silicon carbide, gallium nitride wafer, or the like.

[0043] The external electric field can be provided by one or more of an electrochemical workstation, a DC power supply, a potentiostat, a battery, and the like.

[0044] The method for electrochemical mechanical thinning of a semiconductor wafer using the above-mentioned semiconductor wafer electrochemical mechanical thinning processing apparatus specifically includes the following steps:

[0045] S1: The semiconductor wafer 7 is cleaned by a wet cleaning method to remove dust, impurities and oxides on the surface of the semiconductor wafer 7, and then dried with a nitrogen gun.

[0046] S2: The thickness H of the wafer is measured, and the amount of removal (Hh) of the thinning process is determined based on the target thickness h to be thinned.

[0047] S3: The semiconductor wafer 7 is fixed to the upper end of the wafer fixing device 9 by vacuum suction.

[0048] S4: The slide block on which the grinding wheel dresser 11 and the wafer fixing device 9 are positioned is moved to move the grinding wheel dresser 11 below the grinding tool system, and the electric lift plate 21 on which the grinding tool system 1 is positioned is driven to move it downward until the bottom of the grinding wheel 3 comes into close contact with the surface of the grinding wheel dresser 11 and reaches the dressing start position, and the dressing amount is set.

[0049] S5: The drive motors of the grinding tool system 1 and the dresser 11 are started, and the cup-shaped grinding wheel 3 is dressed based on the set dressing amount. After the dressing is completed, the drive motors are stopped, and the grinding tool system 1 is lifted upward by the electric lifting plate 21.

[0050] S6: Move the slide block on which the grinding wheel dresser 11 and the wafer fixing device 9 are located to move the wafer fixing device 9 below the grinding tool system 1 until the entire surface of the semiconductor wafer 7 to be processed is located within the orthogonal projection range of the grinding wheel 3, the specific position is adjusted according to the requirements for the eccentricity of the semiconductor wafer 7 and the grinding wheel 3, and drive the electric lifting plate 21 to move the grinding tool system 1 downward until the bottom of the cup-shaped diamond grinding wheel 3 is in close contact with the surface of the semiconductor wafer 7 and reaches the starting position of the thinning process.

[0051] S7: The peristaltic pump 14 is started, and the electrolyte filter 13 and the thermostatic water bath 12 are operated to perform circulation and filtration of the electrolyte and temperature control (temperature control is not required).

[0052] S8: Set electrochemical anodization modification parameters including voltage, current, time, etc., by the electrochemical workstation 15.

[0053] S9: The removal amount and feed amount for the thinning process are set, and the drive motors for the grinding tool system 1 and the wafer fixing device 9 are started.

[0054] S10 The electrochemical workstation 15 is started to apply voltage / current.

[0055] S11: A thinning process is performed, and the semiconductor wafer 7 undergoes an anodizing reaction with the electrolyte 5 due to the action of the electric field, producing an oxide on the surface of the semiconductor wafer 7 that is lower in hardness than the base material of the semiconductor wafer. Furthermore, the semiconductor wafer 7 is ground and removed to a predetermined position by the relative movement of the grindstone 3 and the semiconductor wafer 7, thereby thinning the wafer to a target thickness h.

[0056] S12 After the thinning is completed, the waste liquid is sucked, collected and discharged, the vacuum suction device is stopped, and the thinned wafer is taken out.

[0057] 2, the working principle of the present invention is that before processing, the surface of the semiconductor wafer 7 has deeper and larger damage 19 caused by wire cutting, which is modified by electrochemical anodization to generate a soft oxide layer 17, and then the oxide layer 17 is removed by diamond abrasive grains 16, thereby realizing the thinning processing of the semiconductor wafer and the removal of the damaged layer. Since the diamond grindstone is used in the thinning process, the hardness of the diamond abrasive grains is not only higher than the oxide layer, but also higher than the semiconductor wafer body, so that the diamond abrasive grains remove the damaged layer and the semiconductor wafer body at the same time, causing relatively shallow damage 18 on the surface of the semiconductor wafer, and these damages also react quickly with the electrolyte under the action of the electric field to generate oxide 17. [Explanation of symbols]

[0058] 1 Grinding Tool System 2 Grinding Base 3. Grindstone 4 Electrolyte Tank 5 Electrolyte 6 Cathodic conductive slip ring 7. Semiconductor Wafers 8 Vacuum suction fixing plate 9 Wafer holding device 10 Anode conductive slip ring 11 Grindstone dresser 12 Thermostatic water bath 13 Electrolyte filter 14 Peristaltic Pump 15 Electrochemical Workstation 16 Diamond abrasive grains 17 Oxide layer 18 Shallow Damage Layer 19 Deep Damage Layer 20 First servo motor 21 Electric lift plate 22 Bottom plate

Claims

1. The present invention relates to a grinding tool system (1), the grinding tool system (1) being attached to a lifting device, a wafer fixing device (9) being provided below the grinding tool system (1), the grinding tool system (1) including a grinding base (2) and a grinding wheel (3), the grinding wheel (3) being fixed to a lower end of the grinding base (2), The grinding base (2) is connected to a cathode conductive slip ring (6), an anode conductive slip ring (10) is attached to the wafer fixing device (9), and during thinning, the anode conductive slip ring (10) contacts the semiconductor wafer (7) being thinned; The outer ring of the cathode conductive slip ring (6) is connected to the negative pole of a power supply device, and the outer ring of the anode conductive slip ring (10) is connected to the positive pole of the power supply device, and during the thinning process, the grinding substrate (2) and the semiconductor wafer (7) to be thinned are both in contact with the electrolyte (5); The wafer fixing device (9) is mounted in an electrolyte tank (4) for storing the electrolyte (5), a dressing device for dressing the grinding wheel (3) is provided below the grinding tool system (1), the dressing device is provided within the electrolyte tank (4), a slide block is fixed to a lower end of the electrolyte tank (4), and the slide block is slidably connected to a slide rail attached to a bottom plate (22).

2. 2. The electrochemical mechanical thinning apparatus for large diameter semiconductor wafers according to claim 1, wherein the semiconductor wafer (7) is fixed to the wafer fixing device (9) by vacuum suction or adhesive.

3. 3. The electrochemical mechanical thinning apparatus for large-diameter semiconductor wafers according to claim 2, characterized in that a notch is provided in the upper part of the wafer fixing device (9), a vacuum suction fixing plate (8) is provided in the notch, a through hole is opened in the bottom of the notch, the through hole is connected to a vacuum pump by a tube and a swivel joint, and the vacuum suction fixing plate (8) is for setting the semiconductor wafer (7) to be thinned.

4. 2. The apparatus for electrochemical mechanical thinning of large diameter semiconductor wafers according to claim 1, wherein the power supply device is an electrochemical workstation (15), the electrochemical workstation (15) having a counter electrode connected to the outer ring of the cathode conductive slip ring (6) and a working electrode connected to the outer ring of the anode conductive slip ring (10).

5. 2. The electrochemical mechanical thinning apparatus for large-diameter semiconductor wafers according to claim 1, wherein an outlet of the electrolyte tank (4) is connected to an input end of a peristaltic pump (14) by piping, an output end of the peristaltic pump (14) is connected to an input end of an electrolyte filter (13) by piping, and an output end of the electrolyte filter (13) is connected to an inlet of the electrolyte tank (4) by piping.

6. 6. The electrochemical mechanical thinning apparatus for large-diameter semiconductor wafers according to claim 5, further comprising a thermostatic water tank (12) provided in a piping between an output end of the electrolyte filter (13) and an inlet of the electrolyte tank (4).

7. 2. A method for electrochemical mechanical thinning of a large-diameter semiconductor wafer by the electrochemical mechanical thinning apparatus of claim 1, comprising: A step S1 of cleaning and drying the semiconductor wafer (7); A step S2 of measuring a thickness H of the semiconductor wafer (7) and determining a thinning removal amount H-h based on a target thinning thickness h; A step S3 of fixing the semiconductor wafer (7) to the wafer fixing device (9); Step S4: moving the wafer fixing device (9) below the grinding tool system (1) and moving the grinding tool system (1) downward until the bottom of the grinding wheel (3) is in close contact with the surface of the semiconductor wafer (7); Step S5 of setting electrochemical anodic oxidation modification parameters by the power supply device; Step S6: setting the removal amount and feed amount of the thinning process and starting the drive motors of the grinding tool system (1) and the wafer fixing device (9); Step S7 of starting up the power supply device to apply a voltage / current; and step S8 of performing thinning processing on a large-diameter semiconductor wafer, and anodizing the semiconductor wafer (7) with an electrolyte by the action of an electric field to generate an oxide having a hardness lower than that of a base material of the semiconductor wafer on the surface of the semiconductor wafer, and removing the semiconductor wafer (7) until it is thinned to a target thickness h by relative movement between the grindstone (3) and the semiconductor wafer (7).

8. 8. The method for electrochemical mechanical thinning of large-diameter semiconductor wafers according to claim 7, further comprising the steps of: starting a peristaltic pump (14) and operating an electrolyte filter device (13) before step S5; and, if it is necessary to control the temperature of the electrolyte, operating a thermostatic water bath (12) to set the temperature.

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