Sub-caliber electrochemical polishing device applying hollow infusion

Abstract

The utility model discloses a sub-aperture electrochemical polishing device applying hollow infusion, and belongs to the technical field of electrochemical mechanical polishing. The hollow polishing head comprises a hollow polishing head body and a conductive module, a liquid flow channel for electrolyte to flow is formed in the hollow polishing head body, the machining face of the hollow polishing head body is a plane, the plane is used for being attached to the surface of a workpiece, and a liquid outlet hole communicated with the liquid flow channel is formed in the side wall, close to the plane, of the hollow polishing head body. The conductive module is used for connecting the positive electrode and the negative electrode of a power source to the workpiece and the polishing head correspondingly. According to the method, the balance between the electrolysis rate and the mechanical removal rate can be well achieved, and hard and brittle materials difficult to remove are efficiently removed.

Description

Technical Field

[0001] This application relates to the technical field of electrochemical mechanical polishing, and particularly to a sub-aperture electrochemical polishing device using hollow liquid infusion. Background Art

[0002] In the semiconductor field, hard and brittle materials such as silicon carbide (SiC) are widely used in high-performance devices due to their large bandgap width; in the field of optical imaging, SiC has greater specific stiffness and thermal stability compared to materials such as quartz glass and beryllium metal. This enables silicon carbide mirrors to have smaller weights and better thermal stability under the same optical aperture and accuracy requirements.

[0003] However, the hardness of single-crystal SiC is very high, second only to diamond and cubic boron nitride in nature. In addition, due to its chemical inertness, single-crystal SiC hardly reacts with acid or alkali solutions. Compared with traditional metal chemical mechanical polishing, electrochemical mechanical polishing uses an external circuit to oxidize the material surface, thereby achieving low pressure, high controllability, and good material removal efficiency, and is expected to eliminate these problems.

[0004] At present, most domestic electrochemical experimental devices use full-aperture polishing. Compared with sub-aperture polishing, full-aperture polishing has lower efficiency and poorer accuracy, and is prone to edge effects.

[0005] Such as Figure 1 As shown, this polishing device places the liquid storage tank above the workpiece, making the processing area the opening area of the bottom surface of the liquid storage tank, rather than the entire surface, and it is impossible to achieve electrochemical polishing of the entire surface. As

[0006] Such as Figure 2 As shown, Patent CN202410286092.8 discloses an electrochemical mechanical polishing device and method, and the entire experiment is carried out immersed in the electrolyte. This method cannot control the balance between the polishing rate and the electrolysis reaction rate, which will affect the surface composition and surface accuracy. Utility Model Content

[0007] In order to better achieve the balance between the electrolysis rate and the mechanical removal rate and realize the efficient removal of hard and brittle materials that are difficult to remove, this application provides a sub-aperture electrochemical polishing device using hollow liquid infusion.

[0008] The sub-aperture electrochemical polishing device using hollow liquid infusion provided by this application adopts the following technical solutions:

[0009] A sub-caliber electrochemical polishing device using hollow infusion, comprising a hollow polishing head and a conductive module. A liquid flow channel for the electrolyte to flow through is provided inside the hollow polishing head. The processing surface of the hollow polishing head is a plane, which is used to fit with the surface of the workpiece. Liquid outlet holes communicating with the liquid flow channel are provided on the side wall of the hollow polishing head close to the plane. The conductive module is used to connect the positive and negative poles of the power supply to the workpiece and the polishing head respectively.

[0010] By adopting the above technical solution, the plane fits with the surface of the workpiece, enabling the electrolyte to reach the processing part in a timely manner. Under the energized state, an electrolytic reaction will occur on the surface of the workpiece, and chemical reactions will occur simultaneously at both poles. After the surface of the workpiece loses electrons, oxides with significantly reduced hardness are generated on the surface and passivation occurs and no longer reacts. At this time, the oxides are quickly removed by the rotation after the contact between the hollow polishing head and the surface of the workpiece, so as to obtain a smooth and clean surface. At the same time, in the field of electrochemical polishing, if a curved surface is used to polish the surface of the workpiece, the cross-section of the polished workpiece will present a W-shaped removal profile. However, the present application adopts a plane polishing method, which can effectively solve the problem of the W-shaped removal profile.

[0011] Optionally, the electrochemical polishing device further comprises a workbench and a conductive block. The conductive block is installed on the top of the workbench, and the top surface of the conductive block abuts against the workpiece. The conductive module is electrically connected to the workpiece through the conductive block.

[0012] By adopting the above technical solution, the conductive block is fixed on the workbench and connected to the workpiece, so that power can be quickly supplied between the workpiece and the hollow polishing head when different workpieces are replaced, improving the polishing efficiency.

[0013] Optionally, the upper surface area of the conductive block is larger than the lower surface area of the workpiece.

[0014] By adopting the above technical solution, it can adapt to more workpieces of different sizes and improve its adaptability.

[0015] Optionally, an insulating washer is sleeved on the peripheral side of the workpiece, and the lower surface of the insulating washer covers the upper surface of the conductive block.

[0016] By adopting the above technical solution, it prevents the electrolyte from contacting the conductive block and reduces the occurrence of short-circuit phenomena.

[0017] Optionally, a plurality of liquid outlet holes are provided, and the number of the plurality of liquid outlet holes changes from dense to sparse in the direction from the center of the plane to the edge of the plane.

[0018] By adopting the above technical solution, the liquid flow rate at the center of the polishing surface is made relatively consistent with the liquid flow rate at the edge of the polishing surface, realizing uniform liquid outlet of the electrolyte.

[0019] Optionally, the hollow polishing head includes a rotating main shaft, a connecting shaft, and a planar polishing head that are connected in sequence. A temporary storage cavity is formed in the rotating main shaft, a connecting hole is formed in the connecting shaft, and a uniform flow cavity is formed in the planar polishing head. The temporary storage cavity, the connecting hole, and the uniform flow cavity are communicated in sequence, and a channel switch is arranged in the connecting hole.

[0020] By adopting the above technical solution, the temporary storage cavity stores the electrolyte. When electrolysis is required, the channel switch is controlled to control the electrolyte to flow out from the liquid outlet hole. The position setting of the channel switch can accelerate the liquid outlet speed of the electrolyte and improve the polishing control accuracy. The setting of the uniform flow cavity can improve the uniform distribution of the electrolyte and ensure the polishing effect.

[0021] Optionally, a liquid inlet hole is formed at the center of one end of the rotating main shaft away from the connecting shaft.

[0022] By adopting the above technical solution, a rotary joint can be installed at the liquid inlet hole to facilitate the supply of the electrolyte.

[0023] Optionally, a conductive slip ring is sleeved on the outer periphery of the hollow polishing head, and the conductive module is electrically connected to the hollow polishing head through the conductive slip ring.

[0024] By adopting the above technical solution, the normal rotation and normal conduction of the hollow polishing head are ensured.

[0025] Optionally, the electrochemical polishing device further includes a robotic arm, and the output end of the robotic arm is connected to the hollow polishing head.

[0026] By adopting the above technical solution, the position of the hollow polishing head can be accurately controlled by using the mechanical part, and the polishing effect is ensured.

[0027] Optionally, the electrochemical polishing device further includes a fixture, and the fixture clamps and fixes the workpiece along the circumferential side of the workpiece.

[0028] By adopting the above technical solution, the rapid installation or disassembly of the workpiece is realized, and the polishing efficiency is improved.

[0029] In summary, the present application includes at least one of the following beneficial technical effects:

[0030] 1. The electrochemical mechanical polishing device of the present application can well adapt to the change of the workpiece size. By using the principle of electrolysis first and then mechanical removal, the efficient removal of hard and brittle materials that are difficult to remove can be realized, and the balance between the electrolysis rate and the mechanical removal rate can be better achieved.

[0031] 2. By designing the hollow polishing head and the internal flow channel structure, the uniform supply of the electrolyte is realized, and the processing efficiency and accuracy of the electrochemical polishing device are improved.

[0032] 3. The design of the conductive module and the workbench enables the workpiece to receive current stably and safely, ensuring the smooth progress of the electrochemical polishing process.

[0033] 4. The reasonable layout of multiple liquid outlet holes and the setting of insulating gaskets effectively avoid the edge effect and improve the processing quality. Description of the Drawings

[0034] Figure 1 It is a schematic structural diagram of one of the polishing methods in the related art.

[0035] Figure 2 It is a schematic structural diagram of another polishing method in the related art.

[0036] Figure 3 It is a groove-shaped removal morphology diagram formed after polishing with a curved polishing surface of the polishing head.

[0037] Figure 4 It is a W-shaped removal contour diagram formed after polishing with a curved polishing surface of the polishing head.

[0038] Figure 5 It is a schematic diagram of the overall structure of the embodiment of the present application.

[0039] Figure 6 It is a cross-sectional view of the hollow polishing head in the embodiment of the present application.

[0040] Figure 7 It is a schematic diagram of the distribution of the liquid outlet holes of the hollow polishing head in the embodiment of the present application.

[0041] Figure 8 It is a cross-sectional view mainly showing the insulating gasket in the embodiment of the present application.

[0042] Figure 9 It is a schematic diagram of the overall structure showing the robotic arm in the embodiment of the present application.

[0043] Description of the Reference Numerals:

[0044] 10. Workpiece; 20. Workbench; 30. Conductive block; 40. Fixture; 41. Clamping block; 411. Long strip hole; 42. Fastening bolt; 50. Hollow polishing head; 51. Rotating main shaft; 511. Temporary storage cavity; 512. Liquid inlet hole; 52. Connecting shaft; 521. Connecting hole; 53. Flat polishing head; 531. Uniform flow cavity; 532. Plane; 533. Liquid outlet hole; 60. Conductive slip ring; 70. Conductive module; 80. Insulating gasket; 90. Robotic arm. Detailed Embodiment

[0045] The following will further elaborate on the present application in conjunction with the attached Figure 3-9 drawings.

[0046] In the related art, when the polishing surface of the polishing head is designed as a curved surface, during the process of polishing the workpiece with the polishing head, a groove-shaped removal topography as shown in Figure 3 will be formed. When the groove-shaped removal topography is in cross-section, it will present a W-shaped removal profile as shown in Figure 4 . The W-shaped removal profile means that when the polishing head contacts the workpiece, the width of the contact area will change periodically, which may cause uneven polishing of the workpiece surface. And due to the non-uniformity of the contact area, the workpiece surface may be subjected to excessive polishing pressure in some areas, resulting in damage or scratches.

[0047] Therefore, the embodiment of the present application provides a sub-aperture electrochemical polishing device using hollow liquid infusion, which can effectively solve the above problems, and can better achieve the balance between the electrolysis rate and the mechanical removal rate, and achieve the efficient removal of difficult-to-remove hard and brittle materials.

[0048] As shown in Figure 5 , a sub-aperture electrochemical polishing device using hollow liquid infusion provided by the embodiment of the present application. The device mainly includes a workbench 20, a conductive block 30, a fixture 40, a hollow polishing head 50, a conductive slip ring 60, and a conductive module 70.

[0049] Among them, a groove is opened at the center of the top surface of the workbench 20, and the conductive block 30 is installed in the groove, and the top surface of the conductive block 30 is flush with the top surface of the workbench 20. Optionally, the conductive block 30 is a metal block.

[0050] The workpiece 10 is placed on the conductive block 30, and the upper surface area of the conductive block 30 is designed to be larger than the lower surface area of the workpiece 10 to ensure good electrical connection for workpieces 10 of various sizes.

[0051] The fixture 40 clamps and fixes the workpiece 10 placed on the conductive block 30. Specifically, the fixture 40 may include a clamping block 41 and a fastening bolt 42. The clamping block 41 is provided with a long strip hole 411 extending along the radial direction of the workbench 20, and the fastening bolt 42 is threadedly connected to the workbench 20 to fix the clamping block 41. The clamping block 41 abuts against the peripheral side of the workpiece 10 to realize the clamping and fixing of the workpiece 10.

[0052] Referring to Figure 5 and Figure 6, specifically regarding the structure of the hollow polishing head 50, it is successively connected by a rotating main shaft 51, a connecting shaft 52, and a planar polishing head 53. The rotating main shaft 51, the connecting shaft 52, and the planar polishing head 53 can be integrally provided. A temporary storage cavity 511 is opened inside the rotating main shaft 51 for temporarily storing electrolyte. At the central position of the end of the rotating main shaft 51 far from the connecting shaft 52, a liquid inlet hole 512 is also opened. Through this liquid inlet hole 512, electrolyte can be conveniently injected. A connecting hole 521 is opened inside the connecting shaft 52, and a channel switch (not shown in the figure) is equipped in the connecting hole 521. By controlling this channel switch, the flow of electrolyte can be precisely controlled. A flow equalizing cavity 531 is opened inside the planar polishing head 53. The temporary storage cavity 511, the connecting hole 521, and the flow equalizing cavity 531 are successively connected to form a liquid flow path to ensure that the electrolyte can smoothly flow inside the hollow polishing head 50 into the flow equalizing cavity 531.

[0053] Meanwhile, the processing surface of the planar polishing head 53 is a plane 532, and this plane 532 is designed to closely fit the surface of the workpiece 10, so that the electrolyte can be evenly distributed on the processing surface, thereby solving the problem of the W-shaped removal profile. Among them, liquid outlet holes 533 communicating with the flow equalizing cavity 531 are opened on the side wall close to the processing plane 532.

[0054] Referring to Figure 5 and Figure 7 , the liquid outlet holes 533 are specifically designed to be multiple, and the number of these liquid outlet holes 533 changes from dense to sparse along the direction from the center of the plane 532 to the edge of the plane 532, so that the electrolyte can evenly and appropriately flow to each position on the surface of the workpiece 10.

[0055] Referring to Figure 5 , a conductive slip ring 60 is sleeved on the outer periphery of the rotating main shaft 51 and the rotating main shaft 51 can rotate relative to the conductive slip ring 60.

[0056] The conductive module 70 includes a power supply. The positive and negative poles of the power supply are respectively connected to the conductive block 30 and the conductive slip ring 60, thereby realizing the electrochemical polishing process.

[0057] Referring to Figure 8 , in order to prevent the electrolyte from directly contacting the conductive block 30 and causing a short circuit, an insulating washer 80 is also sleeved on the peripheral side of the workpiece 10. The insulating washer 80 can be bonded to the workpiece 10 through epoxy resin. The lower surface of the insulating washer 80 can cover the upper surface of the conductive block 30 except the surface in contact with the workpiece 10. Before sleeving the insulating washer 80, the workpiece 10 can also be pretreated, and an insulating and anti-corrosion treatment is carried out on the peripheral side of the workpiece 10 to further prevent the occurrence of short circuit phenomena.

[0058] Referring to Figure 9, In addition, the electrochemical polishing device provided by the embodiment of the present application is also equipped with a robotic arm 90. The output end of the robotic arm 90 is directly connected to the rotating main shaft 51. The precise adjustment of the position of the polishing head can be realized by using the robotic arm 90, and the polishing effect can be optimized.

[0059] The implementation principle of the embodiment of the present application is as follows: The positive electrode of the power supply conducts electricity to the conductive block 30 in the workbench 20 through a wire. The conductive block 30 contacts the workpiece 10 to conduct electricity to the workpiece 10. The negative electrode of the power supply conducts electricity to the hollow polishing head 50 through the conductive slip ring 60. During electrolysis, the electrolyte is controlled to flow out from the liquid outlet hole 533 of the hollow polishing head 50, so as to form a loop between the workpiece 10 and the hollow polishing head 50. In the energized state, an electrolytic reaction will occur on the surface of the workpiece 10, and chemical reactions will occur at both poles simultaneously. After the surface of the workpiece 10 loses electrons, oxides with significantly reduced hardness are generated on the surface and passivation occurs and no longer reacts. At this time, the oxides are quickly removed by the rotation after the contact between the hollow polishing head 50 and the surface of the workpiece 10, so as to obtain a smooth and clean surface.

[0060] The electrochemical polishing device of the present application can well adapt to the change of the size of the workpiece 10. By using the principle of first electrolyzing and then mechanically removing, the efficient removal of hard and brittle materials that are difficult to remove can be realized, and the balance between the electrolysis rate and the mechanical removal rate can be better achieved. And the robot is easy to operate and has a low cost.

[0061] The above are all the preferred embodiments of the present application, and the protection scope of the present application is not limited by this. Therefore, all equivalent changes made according to the structure, shape, and principle of the present application should be covered within the protection scope of the present application.

Claims

1. A sub-caliber electrochemical polishing device using hollow infusion, characterized in that: The invention comprises a hollow polishing head (50) and a conductive module (70), wherein a liquid flow channel for electrolyte circulation is provided inside the hollow polishing head (50), a processing surface of the hollow polishing head (50) is a plane (532), the plane (532) is used to fit with the surface of a workpiece (10), a liquid outlet (533) connected to the liquid flow channel is provided on a side wall of the hollow polishing head (50) close to the plane (532), and the conductive module (70) is used to connect the positive and negative electrodes of a power source to the workpiece (10) and the hollow polishing head (50), respectively.

2. A sub-caliber electrochemical polishing device using hollow infusion according to claim 1, characterized in that: The electrochemical polishing device further comprises a workbench (20) and a conductive block (30), wherein the conductive block (30) is mounted on the top of the workbench (20), the top surface of the conductive block (30) abuts against the workpiece (10), and the conductive module (70) is electrically connected to the workpiece (10) via the conductive block (30).

3. A sub-caliber electrochemical polishing device using hollow infusion according to claim 2, characterized in that: The upper surface area of ​​the conductive block (30) is larger than the lower surface area of ​​the workpiece (10).

4. A sub-caliber electrochemical polishing device using hollow infusion according to claim 3, characterized in that: An insulating gasket (80) is sleeved on the peripheral side of the workpiece (10), and the lower surface of the insulating gasket (80) covers the upper surface of the conductive block (30).

5. The sub-caliber electrochemical polishing device using hollow infusion according to claim 1, characterized in that: The liquid outlet holes (533) are arranged in a plurality, and the number of the plurality of liquid outlet holes (533) changes from dense to sparse along the direction from the center of the plane (532) to the edge of the plane (532).

6. A sub-caliber electrochemical polishing device using hollow infusion according to claim 1, characterized in that: The hollow polishing head (50) comprises a rotating main shaft (51), a connecting shaft (52) and a plane polishing head (53) which are connected in sequence; a temporary storage chamber (511) is provided in the rotating main shaft (51); a connecting hole (521) is provided in the connecting shaft (52); a flow balancing chamber (531) is provided in the plane polishing head (53); the temporary storage chamber (511), the connecting hole (521) and the flow balancing chamber (531) are connected in sequence; and a channel switch is provided in the connecting hole (521).

7. A sub-caliber electrochemical polishing device using hollow infusion according to claim 6, characterized in that: A liquid inlet hole (512) is provided at the centre of one end of the rotating main shaft (51) away from the connecting shaft (52).

8. A sub-caliber electrochemical polishing device using hollow infusion according to claim 1, characterized in that: A conductive slip ring (60) is sleeved on the outer periphery of the hollow polishing head (50), and the conductive module (70) is electrically connected to the hollow polishing head (50) via the conductive slip ring (60).

9. A sub-caliber electrochemical polishing device using hollow infusion according to claim 1, characterized in that: The electrochemical polishing device also includes a mechanical arm (90), wherein an output end of the mechanical arm (90) is connected to the hollow polishing head (50).

10. The sub-caliber electrochemical polishing device using hollow infusion according to claim 1, characterized in that: The electrochemical polishing device also includes a clamp (40), wherein the clamp (40) clamps and fixes the workpiece (10) along the circumferential edge of the workpiece (10).

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