A polishing method for through silicon via products

Abstract

This invention relates to the field of polishing technology for through-silicon via (TSV) products, and more specifically, to a polishing method for TSV products, comprising the following steps: S1: Determining an electrorheological polishing machine, an elastic conductive element, an insulating support plate with a through cavity, and a workpiece to be polished; S2: Fixing the insulating support plate to the workpiece support platform of the electrorheological polishing machine; placing the elastic conductive element into the through cavity; ensuring that the outer surface of the elastic conductive element is coated with conductive grease; S3: Fixing the workpiece to be polished onto the insulating support plate; ensuring that the other end of the elastic conductive element abuts against a TSV, with the center line of the TSV coinciding with the rotation axis of the polishing electrode; S4: Reversing the electrorheological polishing fluid; S5: Connecting the polishing electrode to the positive terminal of a voltage source, and connecting the workpiece support platform to the negative terminal of the voltage source or grounding; then driving the polishing electrode to rotate; S6: Removing small metal dots from the surface of the workpiece to be polished. This invention can completely remove the metal layer without damaging the insulating layer and the TSV of the workpiece to be polished.

Description

Technical Field

[0001] This invention relates to the field of polishing technology for through-silicon via (TSV) products, and more specifically, to a polishing method for TSV products. Background Technology

[0002] Currently, a key development direction for high-end chips is the adoption of advanced packaging technologies to achieve three-dimensional chip manufacturing, thereby improving chip integration. Chip stacking technology is one of the important means to achieve three-dimensional chip manufacturing; however, the interconnection between chips presents a significant challenge during chip stacking.

[0003] TSV (Through Silicon Via) technology, also known as through-silicon via (TSV) technology, enables vertical electrical interconnection vias. Key steps in this process include creating TSVs, filling TSVs, and CMP (Chemical Mechanical Polishing) planarization. Creating TSVs involves fabricating holes that penetrate the wafer; filling TSVs involves using metals such as copper or tungsten to fill these holes; and CMP planarization uses chemical mechanical methods to polish away any remaining metal layer on the wafer surface after filling. This involves first chemically etching to soften the metal layer on the wafer surface, and then mechanically polishing to remove the softened metal layer. For example, a prior art chemical mechanical polishing pad and method are disclosed. The chemical mechanical polishing method involves applying a polishing slurry to the working surface of the polishing pad or the surface of the material being polished, bringing the working surface of the polishing pad into contact with the surface of the material being polished, and moving the polishing pad relative to the material being polished, performing chemical mechanical polishing on the material under low or ultra-low pressure.

[0004] Since wafer integrity directly affects chip performance, wafer polishing must minimize or eliminate damage. When removing the metal layer from the wafer surface, it is crucial to ensure that all excess metal is thoroughly removed to prevent it from affecting subsequent manufacturing steps and to avoid metal residue impacting chip operation. In the aforementioned prior art solutions, hard particles in the polishing slurry and abrasive particles from the polishing pad may cause scratches or dents in the wafer's insulating layer or the metal within the through-silicon vias (TSVs), negatively impacting product quality. Furthermore, excessively high or uneven corrosion rates in the polishing slurry can easily lead to insufficient metal layer removal and erosion of the wafer's insulating layer or the metal within the TSVs. Summary of the Invention

[0005] To address the problems of insufficient metal layer removal and damage to the surface of the workpiece's insulating layer or through-silicon vias that easily occur when polishing workpieces using existing technologies, this invention provides a polishing method for through-silicon via products, characterized by significantly reducing metal residue without damaging the workpiece's insulating layer and through-silicon vias.

[0006] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows:

[0007] A polishing method for through-silicon via (TSV) products includes the following steps:

[0008] S1: Determine the electrorheological polishing machine, the elastic conductive component, the insulating support plate with a through cavity, and the workpiece to be polished.

[0009] S2: Fix the insulating support plate to the workpiece support platform of the electrorheological polishing machine, then put the elastic conductive element into the through cavity, so that one end of the elastic conductive element is connected to the workpiece support platform of the electrorheological polishing machine; then pour conductive grease into the through cavity so that the outer surface of the elastic conductive element is covered with conductive grease.

[0010] S3: Fix the workpiece to be polished on the insulating support plate, and then adjust the position of the polishing electrode of the electrorheological polishing machine so that its polishing range is sufficient to cover the metal layer on the workpiece, that is, the polishing electrode can polish all areas of the metal layer in one rotation; and make the other end of the elastic conductive element abut against at least one through-silicon via (TSV) of the workpiece to be polished, wherein the center line of one of the TSVs abutting against the elastic conductive element coincides with the rotation axis of the polishing electrode. The elastic conductive element has elasticity and conductivity, and can maintain abutment against the TSV of the workpiece to be polished. In order to form an electric field between the polishing electrode of the electrorheological polishing machine and the metal layer, the metal layer needs to be connected to the negative terminal of a voltage source or grounded. One preferred solution is to connect the TSV to the negative terminal of a voltage source or grounded. Since the metal layer is connected to the TSV, the metal layer can also be connected to the negative terminal of the voltage source or grounded. However, since the diameter of the TSV is very small, it is difficult to connect the TSV to the voltage source or grounded through wires. By utilizing an elastic conductive element and applying conductive grease to its outer surface, a highly stable electrical connection can be formed between the through-silicon via (TSV) and the workpiece support platform of the electrorheological polishing machine. When the workpiece support platform of the electrorheological polishing machine is connected to the negative terminal of a voltage source or grounded, the elastic conductive element, conductive grease, the TSV connected to the elastic conductive element, and the metal layer connected to the TSV are also connected to the negative terminal of the voltage source or grounded.

[0011] S4: Pour electrorheological polishing fluid onto the surface of the workpiece to be polished, filling the gap between the workpiece and the electrorheological polishing electrode. Electrorheological fluid is a smart material; it is a suspension composed of dielectric particles and insulating oil. Under the action of an electric field, the dielectric particles attract each other to form chains. The shear strength of the electrorheological fluid increases with the electric field strength (up to several hundred kPa), and this change process is very rapid (milliseconds) and continuously controllable. When the electric field is removed, the electrorheological fluid quickly returns to a fluid state. Adding abrasive particles, such as silica, alumina, or cerium oxide, to the electrorheological fluid yields an electrorheological polishing fluid, which can be used as a polishing pad in an electric field.

[0012] S5: Connect the polishing electrode of the current-ratio polishing machine to the positive terminal of the voltage source, and simultaneously connect the workpiece support platform to the negative terminal of the voltage source or ground, so that the metal layer of the workpiece to be polished is connected to the negative terminal of the voltage source or ground, thereby forming an electric field between the polishing electrode of the current-ratio polishing machine and the metal layer of the workpiece to be polished, so that the current-ratio polishing liquid between the polishing electrode of the current-ratio polishing machine and the metal layer forms a flexible polishing head; then drive the polishing electrode of the current-ratio polishing machine to rotate so that the flexible polishing head polishes the metal layer on the surface of the workpiece to be polished.

[0013] S6: Remove a small metal dot remaining on the surface of the workpiece to be polished.

[0014] It should be noted that the through-silicon vias described in this specification include both the through-silicon via structure and the metal filler inside the through-silicon via structure.

[0015] As the principle of electrorheological polishing (EMG) shows, the polishing efficiency of ERG strongly depends on the shear strength of the flexible polishing head formed by the ERG under an electric field. Only when the shear strength of the flexible polishing head is sufficiently high can the metal layer be removed. Based on the characteristic that ERG requires an external electric field, by changing the electric field distribution and controlling the removal rate of the ERG for both conductors and insulators, a high removal rate selectivity can be obtained. That is, a high polishing removal rate is achieved for conductors, while a very low (negligible) removal rate is achieved for insulating layers. Therefore, ERG can be used to selectively remove metal layers in through-silicon via (TSV) manufacturing processes without damaging the insulating layer or the TSV.

[0016] In the above technical solution, the polishing process can be divided into three scenarios depending on the object below the polishing electrode. When the polishing electrode is located above the metal layer, since the polishing electrode is connected to the positive terminal of the voltage source and the metal layer is connected to the negative terminal of the voltage source or grounded, an electric field can be formed between the polishing electrode and the metal layer. The electrorheological polishing fluid between the polishing electrode and the metal layer can form a flexible polishing head. When the polishing electrode rotates, the flexible polishing head has a strong removal effect on the metal layer. When the polishing electrode is located above the insulating layer of the workpiece to be polished, since the insulating layer is not conductive, the electric field between the polishing electrode and the insulating layer is so weak as to be almost zero. The electrorheological polishing fluid between the polishing electrode and the insulating layer cannot form a flexible polishing head and cannot remove the insulating layer. When the metal layer material above a through-silicon via (TSV) that is not connected to an elastic conductive element has been polished clean, and the polishing electrode is located above the TSV, since the TSV is not connected to other areas of the metal layer, it is disconnected from the negative terminal or ground of the voltage source. Therefore, it cannot form a strong electric field with the polishing electrode, and the electrorheological polishing fluid between the polishing electrode and the TSV cannot form a flexible polishing head, thus failing to remove the TSV.

[0017] Understandably, during the polishing process, if all the remaining metal layer material on the surface of the workpiece can be connected to the negative terminal or ground of the voltage source, it can prevent the leaving of insufficiently polished metal layer material in certain areas, thus avoiding "metal islands." Since the removal rate of different areas of the metal layer is proportional to the linear velocity of the flexible polishing head, the removal rate is higher in areas of the metal layer far from the rotation axis of the polishing electrode and lower in areas closer to the rotation axis. Therefore, when all areas of the metal layer are connected to the negative terminal or ground of the voltage source, the metal layer will gradually shrink from the outside to the inside during polishing, eventually leaving a small metal dot located at the rotation axis of the polishing electrode. Because the centerline of one of the through-silicon vias that abut against the elastic conductive element coincides with the rotation axis of the polishing electrode, it can be ensured that the remaining metal layer material on the workpiece can always be connected to the negative terminal or ground of the voltage source. The aforementioned small metal dot is also located at the through-silicon via that abuts against the elastic conductive element. In summary, after polishing the workpiece using the above method, the metal layer on the surface of the workpiece can be completely removed, avoiding metal residue. Moreover, the above method will not damage the insulating layer and through-silicon vias of the workpiece during implementation.

[0018] Preferably, in step S1, the workpiece to be polished is a wafer; in step S3, after fixing the workpiece to be polished on the insulating support plate, the polishing electrode of the electrorheological polisher is adjusted so that its rotation axis coincides with the center line of the workpiece to be polished; at least one of the through-silicon vias connected to the elastic conductive element has its axis coincident with the center line of the workpiece to be polished. In the prior art, most workpieces to be polished are wafers. During the polishing process, the metal layer shrinks radially towards the center of the workpiece, eventually leaving a small dot at the center of the workpiece. The small dot remaining at the center of the workpiece is relatively easy to locate, which is beneficial to improving the removal efficiency of the small dot. Moreover, setting the rotation axis of the polishing electrode, the center line of the workpiece to be polished, and the axis of the through-silicon via abutting the elastic conductive element to coincide is beneficial to improving the polishing efficiency and polishing uniformity of the workpiece to be polished.

[0019] Preferably, in step S1, the insulating support plate is made of zirconia. Insulating support plates made of zirconia have good heat resistance; their dimensions remain essentially unchanged when the external temperature changes, preventing any shift in the position or orientation of the workpiece to be polished. Furthermore, they possess excellent wear resistance, high strength, high hardness, and good fracture toughness, providing stable and reliable support for the workpiece to be polished.

[0020] Preferably, in step S1, the elastic conductive element adopts a spring structure, and the length of the elastic conductive element in the initial state is greater than the height of the cavity. The spring structure has good elasticity, and its elastic deformation performance remains relatively stable after multiple compressions and recoverys, making it more reliable in use.

[0021] Preferably, in step S2, the workpiece to be polished is attached to the insulating support plate.

[0022] Preferably, in step S2, paraffin wax is used to adhere the workpiece to be polished to the insulating support plate. Paraffin wax has good adhesive strength, which can stably adhere the workpiece to be polished to the insulating support plate, avoiding vibration or positional displacement of the workpiece during the polishing process. Moreover, paraffin wax can act as a protective layer, preventing mutual friction between the workpiece and the insulating support plate. After polishing, the paraffin wax can be easily removed by methods such as soaking in hot water without damaging the workpiece.

[0023] Preferably, in step S3, the distance between the polishing electrode of the electrorheological polishing machine and the workpiece to be polished is between 0.1 mm and 1 mm.

[0024] Preferably, in step S4, the electric field strength between the polishing electrode and the polishing electrode of the electrorheological polishing machine is between 1 kV / mm and 4 kV / mm.

[0025] Preferably, in step S6, hydrochloric acid is used to etch away a residual metal dot on the surface of the workpiece to be polished.

[0026] Preferably, in step S6, a grinding tool is used to grind away a residual metal dot on the surface of the workpiece to be polished.

[0027] The beneficial effects of this invention are as follows: By employing a specific connection method, the remaining metal layer on the surface of the workpiece to be polished is stably connected to the negative terminal or ground wire of the voltage source. This allows the electrorheological polishing slurry to form a flexible polishing head between the polishing electrode of the electrorheological polishing machine and the metal layer. By rotating the polishing electrode, the flexible polishing head can selectively polish the metal layer, which not only avoids the formation of metal islands but also prevents damage to the insulating layer and through-silicon vias of the workpiece to be polished. Finally, the small dots remaining on the surface of the workpiece after polishing are removed using hydrochloric acid or a polishing tool, which completely removes the metal layer on the surface of the workpiece, thus improving the quality and performance of through-silicon via products. Attached Figure Description

[0028] Figure 1 This is a flowchart of a polishing method for through-silicon via (TSV) products;

[0029] Figure 2This is a schematic diagram of the grounding method for the workpiece to be polished;

[0030] Figure 3 This is a schematic diagram of the polishing electrode of an electrorheological polishing machine, where the arrow points to the direction of rotation of the polishing electrode;

[0031] Figure 4 yes Figure 3 A top-down view diagram, where the arrows indicate the direction of rotation of the polishing electrode;

[0032] Figure 5 This is a diagram showing the change process of the metal layer on the workpiece during polishing.

[0033] Figure 6 This is a schematic diagram of the surface of the workpiece after polishing;

[0034] Figure 7 yes Figure 6 A magnified schematic diagram of part A in the middle;

[0035] Figure 8 yes Figure 7 A magnified schematic diagram of part B in the middle.

[0036] In the attached diagram: 1-polishing electrode; 2-elastic conductive component; 3-insulating support plate; 301-through cavity; 4-workpiece to be polished; 401-through silicon hole; 5-paraffin wax; 6-workpiece support platform; 7-metal layer. Detailed Implementation

[0037] The technical solution of the present invention will be further described in detail below through specific embodiments and in conjunction with the accompanying drawings:

[0038] Example 1

[0039] This embodiment is the first embodiment of a polishing method for through-silicon via (TSV) products, combined with... Figures 1 to 4 As shown, the method includes the following steps:

[0040] S1: Define the current-ratio polishing machine, the elastic conductive element 2, the insulating support plate 3 with a through cavity 301, and the workpiece 4 to be polished. In this embodiment, a wafer is used as the workpiece 4 to be polished. The substrate of the wafer is silicon with a thickness of 500 μm. The insulating layer above the substrate is silicon oxide with a thickness of 2 μm. The workpiece 4 to be polished has multiple silicon through-holes 401, with a diameter of 50 μm and a depth of 502 μm. The metal layer 7 is located above the insulating layer of the workpiece 4 to be polished. The width of the polishing electrode 1 of the current-ratio polishing machine is equal to the diameter of the workpiece 4 to be polished, and the vertical centerline of the polishing electrode 1 coincides with the axis of rotation. The elastic conductive element 2 adopts a spring structure.

[0041] S2: Fix the insulating support plate 3 onto the workpiece support platform 6 of the current-varying polishing machine, then put the elastic conductive element 2 into the through cavity 301, so that one end of the elastic conductive element 2 is connected to the workpiece support platform 6 of the current-varying polishing machine; then pour conductive grease into the through cavity 301 so that the outer surface of the elastic conductive element 2 is covered with conductive grease.

[0042] S3: Fix the workpiece 4 to be polished on the insulating support plate 3, and then adjust the position of the polishing electrode 1 of the electrorheological polisher so that its rotation axis coincides with the center line of the workpiece 7 to be polished; and make the other end of the elastic conductive element 2 abut against a through-silicon via 401 of the workpiece 4 to be polished, the center line of which coincides with the rotation axis of the polishing electrode 1. The elastic conductive element 2 has elasticity and conductivity, and can maintain contact with the through-silicon via 401 of the workpiece 4 to be polished. In order to form an electric field between the polishing electrode 1 of the electrorheological polisher and the metal layer 7, the metal layer 7 needs to be connected to the negative terminal of the voltage source or grounded. One preferred solution is to connect the through-silicon via 401 to the negative terminal of the voltage source or grounded. Since the metal layer 7 is connected to the through-silicon via 401, the metal layer 7 can also be connected to the negative terminal of the voltage source or grounded. However, since the diameter of the through-silicon via 401 is very small, it is difficult to connect the through-silicon via 401 to the voltage source or ground through a wire. By utilizing the elastic conductive element 2 and attaching conductive grease to its outer surface, the through-silicon via 401 can form a very stable electrical connection with the workpiece support platform 6 of the electrorheological polishing machine through the elastic conductive element 2 and the conductive grease. When the workpiece support platform 6 of the electrorheological polishing machine is connected to the negative terminal of the voltage source or grounded, the elastic conductive element 2, the conductive grease, the through-silicon via 401 connected to the elastic conductive element 2, and the metal layer 7 connected to the through-silicon via 401 are also connected to the negative terminal of the voltage source or grounded.

[0043] S4: Pour electrorheological polishing fluid onto the surface of the workpiece 4 to be polished, ensuring the fluid fills the gap between the workpiece 4 and the electrorheological polishing electrode 1. Electrorheological fluid is a smart material; it is a suspension composed of dielectric particles and insulating oil. Under the influence of an electric field, the dielectric particles attract each other and form chains. The shear strength of the electrorheological fluid increases with the electric field strength (up to several hundred kPa), and this change is very rapid (on the order of milliseconds) and continuously controllable. When the electric field is removed, the electrorheological fluid quickly returns to a fluid state. Adding abrasive particles, such as silica, alumina, or cerium oxide, to the electrorheological fluid yields an electrorheological polishing fluid, which can be used as a polishing pad in an electric field.

[0044] S5: Connect the polishing electrode 1 of the current-ratio polishing machine to the positive terminal of the voltage source, and simultaneously ground the workpiece support platform 6, so that the metal layer 7 of the workpiece 4 to be polished is connected to the ground wire. This creates an electric field between the polishing electrode 1 of the current-ratio polishing machine and the metal layer 7 of the workpiece 4, causing the current-ratio polishing fluid between the polishing electrode 1 and the metal layer 7 to form a flexible polishing head. Then, drive the polishing electrode 1 of the current-ratio polishing machine to rotate so that the flexible polishing head polishes the metal layer 7 on the surface of the workpiece 4. The change process of the metal layer 7 on the surface of the workpiece 4 is as follows: Figure 5 As shown.

[0045] S6: Remove the small metal dot remaining on the surface of the workpiece 4 to be polished.

[0046] It should be noted that the silicon vias 401 described in this specification are all metal fillers inside the silicon via 401 structure.

[0047] The working principle or workflow of this embodiment is as follows: In the above technical solution, the polishing process can be divided into three cases depending on the object below the polishing electrode 1. When the polishing electrode 1 is located above the metal layer 7, since the polishing electrode 1 is connected to the positive terminal of the voltage source and the metal layer 7 is connected to the negative terminal of the voltage source or grounded, an electric field can be formed between the polishing electrode 1 and the metal layer 7. The electrorheological polishing fluid between the polishing electrode 1 and the metal layer 7 can form a flexible polishing head. When the polishing electrode 1 rotates, the flexible polishing head has a strong removal effect on the metal layer 7. When the polishing electrode 1 is located above the insulating layer of the workpiece 4 to be polished, since the insulating layer cannot conduct electricity, the electric field between the polishing electrode 1 and the insulating layer is so weak as to be almost zero. The electrorheological polishing fluid between the polishing electrode 1 and the insulating layer cannot form a flexible polishing head and cannot remove the insulating layer. When the metal layer 7 material above a through-silicon via 401 that is not connected to the elastic conductive element 2 has been polished clean, and the polishing electrode 1 is located above the through-silicon via 401, since the through-silicon via 401 is not connected to other areas of the metal layer 7, the through-silicon via 401 is disconnected from the ground wire. Therefore, a strong electric field cannot be formed between the through-silicon via 401 and the polishing electrode 1. The electrorheological polishing fluid between the polishing electrode 1 and the through-silicon via 401 cannot form a flexible polishing head and cannot remove the through-silicon via 401.

[0048] Understandably, during the polishing process, if all the remaining metal layer 7 material on the surface of the workpiece 4 to be polished can be connected to the ground wire, it can prevent the leaving of insufficiently polished metal layer 7 material in certain areas, thus avoiding "metal islands". Since the removal rate of different areas of the metal layer 7 is proportional to the linear velocity of the flexible polishing head, the removal rate of the area of ​​the metal layer 7 far from the rotation axis of the polishing electrode 1 is larger, and the removal rate of the area close to the rotation axis of the polishing electrode 1 is smaller. Therefore, when all areas of the metal layer 7 are grounded, the metal layer 7 will gradually shrink from the outside to the inside during polishing, finally leaving a small metal dot. This small dot is located at the silicon via 401 that abuts against the elastic conductive element 2. Since the center line of the silicon via 401 that abuts against the elastic conductive element 2 coincides with the rotation axis of the polishing electrode 1, it can be ensured that the remaining metal layer 7 material of the workpiece 4 to be polished can always be connected to the ground wire. In summary, after polishing the workpiece 4 using the above method, the metal layer 7 on the surface of the workpiece 4 can be completely removed, avoiding metal residue. Moreover, the above method will not damage the insulating layer and silicon via 401 of the workpiece 4 during implementation.

[0049] Verification of the effect of this embodiment: as follows Figure 6 As shown, only a small metal dot remains on the surface of the workpiece 4 after polishing. Figure 7 and Figure 8 As shown, the surface of the insulating layer of the workpiece 4 to be polished and the silicon through-holes are free from scratches or dents.

[0050] The beneficial effects of this embodiment are as follows: By using a specific connection method to form a stable connection between the remaining metal layer on the surface of the workpiece to be polished and the negative terminal or ground wire of the voltage source, the electrorheological polishing fluid can form a flexible polishing head between the polishing electrode of the electrorheological polishing machine and the metal layer. By rotating the polishing electrode, the flexible polishing head can selectively polish the metal layer, which not only avoids the formation of metal islands, but also avoids damage to the insulating layer and through-silicon vias of the workpiece to be polished. Finally, the small dots remaining on the surface of the workpiece to be polished after polishing are removed by using hydrochloric acid or a polishing tool, which can completely remove the metal layer on the surface of the workpiece to be polished, which is beneficial to improving the quality and performance of through-silicon via products.

[0051] Example 2

[0052] This embodiment is a second embodiment of a polishing method for through-silicon via (TSV) products. This embodiment further supplements steps S1 to S4 based on embodiment 1. Combined with... Figures 2 to 4As shown, in step S1, the insulating support plate 3 is made of zirconium oxide. The insulating support plate 3 made of zirconium oxide has good heat resistance; its dimensions remain essentially unchanged when the external temperature changes, preventing any change in the position or orientation of the workpiece 4 to be polished. Furthermore, it possesses excellent wear resistance, high strength, high hardness, and good fracture toughness, providing stable and reliable support for the workpiece 4 to be polished.

[0053] Furthermore, in step S2, paraffin wax 5 is used to adhere the workpiece 4 to be polished onto the insulating support plate 3. Paraffin wax 5 has good adhesive strength, which can stably adhere the workpiece 4 to the insulating support plate 3, preventing vibration or positional displacement of the workpiece 4 during the polishing process. Moreover, paraffin wax 5 can act as a protective layer, preventing mutual friction between the workpiece 4 and the insulating support plate 3. After polishing, the paraffin wax 5 can be easily removed by methods such as soaking in hot water without damaging the workpiece 4.

[0054] Furthermore, in step S3, the distance between the polishing electrode 1 of the electrorheological polishing machine and the workpiece 4 to be polished is between 0.1 mm and 1 mm.

[0055] Furthermore, in step S4, the electric field strength between the polishing electrode 1 and the polishing electrode 1 of the electrorheological polishing machine is between 1 kV / mm and 4 kV / mm.

[0056] Other features, working principles, and beneficial effects of this embodiment are the same as those of Embodiment 1.

[0057] Example 3

[0058] This embodiment is a third embodiment of a polishing method for through-silicon via (TSV) products. This embodiment further supplements step S6 based on embodiment 1. In step S6, hydrochloric acid is used to etch away a residual metal dot on the surface of the workpiece 4 to be polished, or a grinding tool is used to grind away the residual metal dot on the surface of the workpiece 4 to be polished.

[0059] Other features, working principles, and beneficial effects of this embodiment are the same as those of Embodiment 2.

[0060] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will recognize that other variations or modifications can be made based on the above description, and it is neither necessary nor possible to exhaustively describe all possible implementations here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A polishing method for through-silicon via (TSV) products, characterized in that, Includes the following steps: S1: Determine the electrorheological polishing machine, the elastic conductive part (2), the insulating support plate (3) with a through cavity (301) and the workpiece to be polished (4); S2: Fix the insulating support plate (3) onto the workpiece support platform (6) of the electrorheological polishing machine, then place the elastic conductive element (2) into the through cavity (301) so that one end of the elastic conductive element (2) is connected to the workpiece support platform (6) of the electrorheological polishing machine; then pour conductive grease into the through cavity (301) and make the outer surface of the elastic conductive element (2) covered with conductive grease. S3: Fix the workpiece (4) to be polished on the insulating support plate (3), and then adjust the position of the polishing electrode (1) of the electrorheological polishing machine so that its polishing range is sufficient to cover the metal layer (7) on the workpiece (4) to be polished, and make the other end of the elastic conductive element (2) abut against at least one silicon through hole (401) of the workpiece (4) to be polished; among the silicon through holes (401) abutting against the elastic conductive element (2), the center line of one of them coincides with the rotation axis of the polishing electrode (1); S4: Pour electrorheological polishing liquid onto the surface of the workpiece (4) to be polished, so that the electrorheological polishing liquid fills the gap between the workpiece (4) to be polished and the electrorheological polishing electrode (1); S5: Connect the polishing electrode (1) of the current-varying polishing machine to the positive terminal of the voltage source, and connect the workpiece support platform (6) to the negative terminal of the voltage source or ground, and then drive the polishing electrode (1) of the current-varying polishing machine to rotate. S6: Remove a metal dot remaining on the surface of the workpiece (4) to be polished.

2. The polishing method for a through-silicon via (TSV) product according to claim 1, characterized in that, In step S1, the workpiece (4) to be polished is a wafer; in step S3, after the workpiece (4) to be polished is fixed on the insulating support plate (3), the polishing electrode (1) of the electrorheological polishing machine is adjusted so that its rotation axis coincides with the center line of the workpiece (4); at least one of the silicon through-holes (401) connected to the elastic conductive element (2) has its axis coincide with the center line of the workpiece (4).

3. The polishing method for a through-silicon via (TSV) product according to claim 1, characterized in that, In step S1, the insulating support plate (3) adopts a zirconium oxide structure.

4. The polishing method for a through-silicon via (TSV) product according to claim 1, characterized in that, In step S1, the elastic conductive element (2) adopts a spring structure, and the length of the elastic conductive element (2) in the initial state is greater than the height of the through cavity (301).

5. The polishing method for a through-silicon via (TSV) product according to claim 1, characterized in that, In step S2, the workpiece (4) to be polished is bonded to the insulating support plate (3).

6. The polishing method for a through-silicon via (TSV) product according to claim 5, characterized in that, In step S2, the workpiece (4) to be polished is bonded to the insulating support plate (3) using paraffin wax.

7. The polishing method for a through-silicon via (TSV) product according to claim 1, characterized in that, In step S3, the distance between the polishing electrode (1) of the electrorheological polishing machine and the workpiece (4) to be polished is between 0.1 mm and 1 mm.

8. The polishing method for a through-silicon via (TSV) product according to claim 1, characterized in that, In step S4, the electric field strength between the polishing electrode (1) and the polishing electrode (1) of the electrorheological polishing machine is between 1kV / mm and 4kV / mm.

9. A polishing method for a through-silicon via (TSV) product according to any one of claims 1 to 8, characterized in that, In step S6, hydrochloric acid is used to etch away a metal dot remaining on the surface of the workpiece (4) to be polished.

10. A polishing method for a through-silicon via (TSV) product according to any one of claims 1 to 8, characterized in that, In step S6, a grinding tool is used to grind away a metal dot remaining on the surface of the workpiece (4) to be polished.

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