Wafer edge multi-pole magnetic field controllable magnetic shear thickening polishing device and method

Abstract

The present application relates to the field of precision and ultra-precision machining, and discloses a wafer edge multi-magnetic-pole magnetic field controllable magnetic shear thickening polishing device and method, which is particularly used for solving the problems of sharp corners, cutting, scratches, burrs and other defects on the wafer edge after chamfering. The device comprises a machine tool, a vacuum chuck, a magnetic field generating device and a medium circulating device. The wafer edge multi-magnetic-pole magnetic field controllable magnetic shear thickening polishing device can form a plurality of controllable coupling magnetic fields in the polishing area by changing the arrangement mode of the three groups of magnetic poles, and can realize polishing of wafer edges with different sizes and angle requirements in combination with high-performance magnetic shear thickening polishing medium.

Description

Technical Field

[0001] This invention relates to precision and ultra-precision machining technology, and in particular provides a device and method for controlling magnetic shearing and thickening polishing of wafer edges using a multi-pole magnetic field. Background Technology

[0002] Wafer edge chamfering and polishing is a key process step in semiconductor manufacturing, aiming to optimize the smoothness and quality of wafer edges, ensuring consistency and reliability in device manufacturing. It not only improves the appearance quality of the wafer but, more importantly, enhances manufacturing efficiency and reliability, laying a solid foundation for the final chip product. However, during wafer edge chamfering and polishing, issues such as edge damage, uneven chamfering, and residual contaminants often arise, potentially affecting wafer quality and the performance of the final device. Therefore, new methods for wafer edge chamfering and polishing are urgently needed. Currently, wafer edge chamfering and polishing methods mainly include mechanical polishing, chemical mechanical polishing, and magnetic field-assisted polishing. During mechanical polishing, stress concentration easily occurs between the polishing pad and the wafer edge, causing temperature rise in localized polishing areas and leading to thermal damage to the wafer edge surface. When using chemical mechanical polishing, chemical waste liquid is present at the wafer edge, requiring further cleaning and polluting the environment, which contradicts the principles of green manufacturing. Compared to mechanical polishing and chemical mechanical polishing, magnetic shear thickening polishing offers advantages such as strong controllability of the magnetic shear thickening polishing medium, high adaptability to processed objects, superior surface / subsurface quality, and stable material removal function, enabling efficient and high-quality polishing of wafer edge chamfers. Designing a magnetic shear thickening polishing device for wafer edges and proposing an efficient and high-quality wafer edge chamfering polishing method has significant theoretical and practical application value. Summary of the Invention

[0003] This invention provides a wafer edge controllable magnetic shearing thickening polishing device and method with multi-pole magnetic field. Based on the wafer polishing technical specifications, a controllable magnetic field generator with multi-pole magnetic field is designed. By adjusting the rotation angle of the three sets of magnetic fields in the magnetic field generator, the distribution of magnetic field lines and the magnetic field strength in the polishing area are adjusted, thereby changing the magnetic field coupling effect. Combined with a high-performance magnetic shearing thickening polishing medium, ultra-precision polishing of wafer edges of different sizes can be achieved.

[0004] The technical solution provided by the present invention for a wafer edge multi-pole magnetic field controllable magnetic shearing thickening polishing device is as follows: 1. The wafer edge magnetic shearing thickening polishing device includes a machine tool, a vacuum chuck, a magnetic field generating device, and a dielectric circulation device. The device includes a machine tool, a vacuum chuck, a magnetic field generating device, and a dielectric circulation device. The magnetic field generating device includes a lower magnetic pole motor, a long transmission shaft, a hollow gear shaft, a left magnetic pole, a lower magnetic pole, a right magnetic pole, a short transmission shaft, a right magnetic pole motor, a right magnetic pole, a lower magnetic pole, a left magnetic pole, a left magnetic pole motor, and a housing. The lower magnetic pole motor is connected to the lower magnetic pole via the long transmission shaft using a spline keyway. The left magnetic pole is installed in a groove inside the left magnetic pole. The right magnetic pole motor is connected to the right magnetic pole via the short transmission shaft using a spline keyway. The right magnetic pole is mounted in a groove inside the right magnetic pole wheel. The left magnetic pole wheel motor uses gears to mesh with the teeth of a hollow gear shaft, which is connected to the left magnetic pole wheel. The hollow gear shaft is fixed to a long rotating shaft by internal nested sliding bearings. The lower magnetic pole is mounted in a groove inside the lower magnetic pole wheel. The media circulation device is fixed in a hollow position below the lower magnetic pole wheel. The magnetic field generating device and the media circulation device are supported by a housing, which is fixedly connected to the machine tool's motion platform. The wafer is clamped onto the machine tool's spindle using a vacuum chuck. The media circulation device includes a nozzle, a circulation pipe, a polishing tank, a media pool, and a media circulation pump. The polishing tank is mounted on the housing, the media pool is mounted inside the housing, the media circulation pump is connected to the media pool at the top and to the circulation pipe at the side, and the nozzle is mounted at the end of the circulation pipe. The wafer is adsorbed onto a vacuum chuck mounted on the machine tool spindle.

[0005] The left and right magnetic poles are magnetized axially, with the N and S poles facing the polishing area and spaced apart. The lower magnetic pole is magnetized radially, with the N and S poles also facing the polishing area and spaced apart. When the three sets of magnetic poles rotate, they can create magnetic fields with different coupling effects: when all three sets of poles have their N poles facing the polishing area (NNN type), a weak magnetic field region is generated within the processing area, which is beneficial for the flow of the medium; when the left and right magnetic poles have their N poles facing the polishing area, and the lower magnetic pole has its S pole facing the polishing area (NSN type), a strong magnetic field region is formed within the polishing area, and the magnetic lines of force diverge from the center to both sides. This arrangement causes the magnetic abrasive to form magnetic chains along the magnetic lines of force, which is beneficial for polishing the wafer edges. When the two magnetic pole arrangements mentioned above appear alternately, an alternating magnetic field will be formed in the polishing area, and the polishing medium will still have a certain degree of fluidity. This magnetic pole arrangement is conducive to the continuous polishing process.

[0006] The gap between the right, lower, and left magnetic pole wheels can be adjusted according to the size of the polished wafer, the intensity of the polishing magnetic field, and the requirements for the distribution of magnetic lines of force.

[0007] The beneficial effects of this invention are as follows: 1. The wafer edge multi-pole magnetic field controllable magnetic shear thickening polishing device of this invention, by changing the magnetic field strength and magnetic line distribution in the polishing area, combined with a high-performance magnetic shear thickening polishing medium, can select different magnetic field arrangements and polishing methods to polish wafer edges of different sizes according to the technical requirements of wafer polishing, which is beneficial for polishing wafer edges of a specific size or with special polishing requirements. 2. The wafer edge multi-pole magnetic field controllable magnetic shear thickening polishing device of this invention improves the controllability of the magnetic field, effectively alleviates the problem of easy adhesion of the medium in the polishing area, improves the recyclability of the polishing medium in the polishing process, and improves the polishing efficiency. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of the overall structure of a wafer edge multi-pole magnetic field controllable magnetic shearing thickening polishing device according to the present invention.

[0009] Figure 2 This is a schematic diagram of the magnetic field generating device of a wafer edge multi-pole magnetic field controllable magnetic shearing thickening polishing device according to the present invention.

[0010] Figure 3 This is a schematic diagram of the dielectric circulation device structure of a wafer edge multi-pole magnetic field controllable magnetic shearing thickening polishing apparatus according to the present invention.

[0011] Figure 4 shows the magnetic field line distribution of a wafer edge multi-pole magnetic field controllable magnetic shearing thickening polishing device according to the present invention, with different magnetic pole orientations.

[0012] In the diagram: 1-1 Machine tool, 1-2 Vacuum chuck, 1-3 Magnetic field generating device, 1-4 Medium circulation device, 1-5 Wafer, 2-1 Lower magnetic wheel motor, 2-2 Long transmission shaft, 2-3 Hollow gear shaft, 2-4 Left magnetic wheel pole, 2-5 Lower magnetic wheel pole, 2-6 Right magnetic wheel pole, 2-7 Short transmission shaft, 2-8 Right magnetic wheel motor, 2-9 Right magnetic wheel, 2-10 Lower magnetic wheel, 2-11 Left magnetic wheel, 2-12 Left magnetic wheel motor, 2-13 Housing, 3-1 Polishing tank, 3-2 Medium pool, 3-3 Medium circulation pump, 3-4 Circulation pipe, 3-5 Nozzle. Detailed Implementation

[0013] Example 1:

[0014] (1) Install the vacuum chuck (1-2) on the machine tool spindle and evacuate the vacuum so that the 6-inch wafer (1-5) is adsorbed on the vacuum chuck (1-2);

[0015] (2) Adjust the gap between the right magnetic pole wheel (2-9), the lower magnetic pole wheel (2-10), and the left magnetic pole wheel (2-11) according to the size of the polished wafer, the intensity of the polishing magnetic field, and the distribution of magnetic lines of force;

[0016] (3) Start the machine tool (1-1), operate the control panel of the machine tool (1-1), move the spindle of the machine tool (1-1), and move the wafer (1-5) to the polishing area so that the distance between the edge of the wafer (1-5) and the polishing tank (3-1) is 1mm;

[0017] (4) Start the magnetic field generating device (1-3) and drive the motor to make the left magnetic pole wheel (2-11), right magnetic pole wheel (2-9) and lower magnetic pole wheel (2-10) rotate, so that the magnetic poles of the left magnetic pole wheel (2-4), right magnetic pole wheel (2-6) and lower magnetic pole wheel (2-5) become N poles facing the polishing area. At this time, a weak magnetic field area is formed in the polishing area.

[0018] (5) Pour the magnetic shear thickening medium into the medium tank (3-2), close the liquid inlet below the polishing tank (3-1), turn on the medium circulation pump (3-3), and the medium is sprayed out from the nozzle (3-5) through the circulation pipe (3-4). The medium enters the polishing tank (3-1). After the medium fills the polishing tank (3-1), turn off the medium circulation pump (3-3).

[0019] (6) Adjust the spindle speed of the machine tool (1-1) to 2000 rpm and drive the motor to rotate the left magnetic pole wheel (2-11), the right magnetic pole wheel (2-9), and the lower magnetic pole wheel (2-10). This will cause the magnetic poles (2-4) of the left magnetic pole wheel and the magnetic poles (2-6) of the right magnetic pole wheel to face the polishing area from the N pole, and the magnetic pole (2-5) of the lower magnetic pole wheel to face the polishing area from the S pole and remain stationary. The polishing area will be filled with a magnetic field, and the medium will accumulate and be distributed along the magnetic lines of force to form a magnetic brush. The polishing operation will then begin.

[0020] (7) The drive motor causes the lower magnetic wheel (2-10) to rotate, so that the N pole of the lower magnetic wheel (2-5) faces the polishing area, a zero magnetic field area is formed in the polishing area, the medium returns to liquid state and begins to flow, the liquid inlet below the polishing tank (3-1) is opened, and the medium flows into the medium pool (3-2);

[0021] (8) After all the medium has flowed into the medium tank (3-2), close the inlet at the bottom of the polishing tank (3-1), turn on the medium circulation pump (3-3) until the medium fills the polishing tank (3-1), adjust the orientation of the left magnetic wheel pole (2-4) and the right magnetic wheel pole (2-6) so that the N pole faces the polishing area, and the S pole of the lower magnetic wheel pole (2-5) faces the polishing area to complete one medium replacement;

[0022] (9) Repeat (4), (5), (6), and (7) to polish the edge of the 6-inch wafer.

[0023] Example 2:

[0024] (1) Install the vacuum chuck (1-2) on the machine tool spindle and evacuate the vacuum so that the 8-inch wafer (1-5) is adsorbed on the vacuum chuck (1-2);

[0025] (2) Adjust the gap between the right magnetic pole wheel (2-9), the lower magnetic pole wheel (2-10), and the left magnetic pole wheel (2-11) according to the size of the polished wafer, the intensity of the polishing magnetic field, and the distribution of magnetic lines of force;

[0026] (3) Start the machine tool (1-1), operate the control panel of the machine tool (1-1), move the spindle of the machine tool (1-1), and move the wafer (1-5) to the polishing area so that the distance between the edge of the wafer (1-5) and the polishing tank (3-1) is 1mm;

[0027] (4) Start the magnetic field generating device (1-3) and drive the motor to make the left magnetic pole wheel (2-11), right magnetic pole wheel (2-9) and lower magnetic pole wheel (2-10) rotate, so that the magnetic poles of the left magnetic pole wheel (2-4), right magnetic pole wheel (2-6) and lower magnetic pole wheel (2-5) become N poles facing the polishing area. At this time, a zero magnetic field area is formed in the polishing area.

[0028] (5) Pour the magnetic shear thickening medium into the medium tank (3-2), open the liquid inlet below the polishing tank (3-1), turn on the medium circulation pump (3-3), the medium is sprayed out from the nozzle (3-5) through the circulation pipe (3-4), and the medium enters the polishing tank (3-1). Adjust the flow rate of the medium circulation pump (3-3) to 30ml / s;

[0029] (6) Adjust the spindle speed of the machine tool (1-1) to 2000 rpm and drive the motor to make the left magnetic pole wheel (2-11), right magnetic pole wheel (2-9), and lower magnetic pole wheel (2-10) rotate continuously. The magnetic pole arrangement is set to alternate between NNN type and NSN type. The medium still has a certain fluidity. While polishing, the medium slowly flows into the medium pool (3-2). After being pumped into the circulation pipe (3-4) by the medium circulation pump (3-3), it is sprayed into the polishing tank (3-1) again by the nozzle (3-5). The medium completes the circulation process and realizes the continuous polishing of the edge of the 8-inch wafer.

[0030] The specific embodiments described above are merely illustrative or explanatory of the principles of the present invention and do not constitute a limitation on the scope of protection of the present invention. Therefore, any modifications, alterations, equivalent substitutions, equivalent structures, and equivalent process changes made to the present invention without departing from the principles and scope of protection described herein should be covered within the scope of protection of the present invention.

Claims

1. A wafer edge multi-pole magnetic field controllable magnetic shearing thickening polishing device, characterized in that: The device includes a machine tool (1-1), a vacuum chuck (1-2), a magnetic field generating device (1-3), and a medium circulation device (1-4). The magnetic field generating device (1-3) includes a lower magnetic pole wheel motor (2-1), a long transmission shaft (2-2), a hollow gear shaft (2-3), a left magnetic pole wheel (2-4), a lower magnetic pole wheel (2-5), a right magnetic pole wheel (2-6), a short transmission shaft (2-7), a right magnetic pole wheel motor (2-8), and a right magnetic pole wheel. (2-9), lower magnetic pole wheel (2-10), left magnetic pole wheel (2-11), left magnetic pole wheel motor (2-12), housing (2-13). The lower magnetic pole wheel motor (2-1) is connected to the lower magnetic pole wheel (2-10) via a long drive shaft (2-2) using a spline keyway. The left magnetic pole (2-4) is installed in a groove inside the left magnetic pole wheel (2-11). The right magnetic pole wheel motor (2-8) is connected to the lower magnetic pole wheel (2-10) via a short drive shaft (2-7) using a spline keyway. The groove fits and connects with the right magnetic pole wheel (2-9). The magnetic pole (2-6) of the right magnetic pole wheel is installed in the groove inside the right magnetic pole wheel (2-9). The left magnetic pole wheel motor (2-12) uses gears to mesh with the teeth of the hollow gear shaft (2-3). The hollow gear shaft (2-3) is connected to the left magnetic pole wheel (2-10). The hollow gear shaft (2-3) is fixed on the long rotating shaft (2-2) by means of internal nested sliding bearings. The lower magnetic pole wheel (2-6) has a magnetic pole (2-6) that is connected to the right magnetic pole wheel (2-9). -5) Installed in the groove inside the lower magnetic pole wheel (2-10), the medium circulation device (1-4) is fixed in the hollow position below the lower magnetic pole wheel (2-10), the magnetic field generating device (1-3) and the medium circulation device (1-4) are supported by the outer shell (2-13), and the outer shell (2-13) is fixedly connected to the motion platform of the machine tool (1-1), and the wafer (1-5) is clamped on the spindle of the machine tool (1-1) by the vacuum chuck (1-2).

2. The wafer edge multi-pole magnetic field controllable magnetic shearing thickening polishing device according to claim 1, characterized in that: By changing the configuration of the magnetic poles in the right magnetic pole wheel (2-9), lower magnetic pole wheel (2-10), and left magnetic pole wheel (2-11) of the magnetic field generating device (1-3), the rotation angles of the left magnetic pole wheel (2-11), right magnetic pole wheel (2-9), and lower magnetic pole wheel (2-10) are adjusted respectively, thereby adjusting the distribution of magnetic field lines and the magnetic field strength in the polishing area, changing the magnetic field coupling effect in the polishing area, and magnetizing the magnetic poles (2-4) of the left magnetic pole wheel and the magnetic poles (2-6) of the right magnetic pole wheel. All directions are axial. The magnetization direction of the lower magnetic wheel pole (2-5) is radial. The left magnetic wheel (2-11) is equipped with the left magnetic wheel pole (2-4) with alternating N and S poles. The right magnetic wheel (2-9) is equipped with the right magnetic wheel pole (2-6) with alternating S and N poles. The lower magnetic wheel (2-10) is equipped with the lower magnetic wheel pole (2-5) with alternating S and N poles. The left magnetic wheel (2-1) is adjusted... 1) Adjust the rotation angle of the right magnetic wheel (2-9) and the lower magnetic wheel (2-10) so that the N poles of the left magnetic wheel (2-4) and the right magnetic wheel (2-6) face the polishing area, and the S pole of the lower magnetic wheel (2-5) faces the polishing area. This generates mutually attracting magnetic lines of force within the polishing area, forming a strong magnetic field region; or adjust the rotation angle of the left magnetic wheel (2-11), the right magnetic wheel (2-9), and the lower magnetic wheel (2-10) so that the left magnetic wheel (2-4)... The N poles of the right magnetic wheel (2-6) and the lower magnetic wheel (2-5) face the polishing area, generating mutually repulsive magnetic lines of force within the polishing area, forming a weak magnetic field region; or the continuous rotation of the left magnetic wheel (2-11), the right magnetic wheel (2-9), and the lower magnetic wheel (2-10) is controlled, and the N and S poles of the left magnetic wheel (2-4), the right magnetic wheel (2-6), and the lower magnetic wheel (2-5) alternately face the polishing area, generating an alternating distribution of magnetic lines of force within the polishing area.

3. The wafer edge multi-pole magnetic field controllable magnetic shearing thickening polishing device according to claim 1, characterized in that: The gap between the right magnetic pole wheel (2-9), the lower magnetic pole wheel (2-10), and the left magnetic pole wheel (2-11) can be adjusted according to the size of the polished wafer, the intensity of the polishing magnetic field, and the requirements for the distribution of magnetic lines of force.

4. The polishing method of the wafer edge multi-pole magnetic field controllable magnetic shearing thickening polishing device according to claim 1, characterized in that: The method includes the following steps: (1) The wafers to be processed (1-5) of different sizes are clamped on the spindle of the machine tool (1-1) by a vacuum chuck (1-2); (2) Determine the configuration of the magnetic poles in the right magnetic pole wheel (2-9), the lower magnetic pole wheel (2-10), and the left magnetic pole wheel (2-11), and load the corresponding magnetic poles; (3) Start the machine tool (1-1), move the wafer (1-5) to the polishing area, adjust the position of the edge of the wafer (1-5), and select the appropriate speed according to the polishing technical specifications of the wafer (1-5); (4) Adjust the rotation angle of the left magnetic wheel (2-11), the right magnetic wheel (2-9) and the lower magnetic wheel (2-10) to generate a weak magnetic field in the polishing area, and transport the polishing medium to the polishing area through the medium circulation device (1-4); (5) Adjust the rotation angles of the left magnetic wheel (2-11), right magnetic wheel (2-9) and lower magnetic wheel (2-10) to generate the required polishing magnetic field in the polishing area and perform polishing. (6) Adjust the rotation angle of the left magnetic wheel (2-11), right magnetic wheel (2-9) and lower magnetic wheel (2-10) to generate a weak magnetic field in the polishing area and open the media circulation device (1-4) to circulate and replace the polishing media; (7) Repeat steps (5) and (6) to achieve efficient and high-quality polishing of the edges of wafers (1-5).

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