A double-sided electroplating tooling suitable for spin plating

Abstract

The application provides a double-sided electroplating tool suitable for rotary sputtering, which comprises a lower ring body, an upper ring body and an upper cover connected in a matching mode, a conductive ring with a group of lower conductive comb teeth is arranged on the lower ring body, an upper conductive ring with a group of upper conductive comb teeth is arranged on the upper ring body, a group of supporting cylinders in contact with the upper cover are uniformly distributed on the upper ring body, a conductive column connected with the upper conductive ring is arranged in the supporting cylinder, a conductive disc is arranged in the upper cover, a group of conductive guide columns corresponding to the conductive column are uniformly distributed on the conductive disc, a conductive shaft extending out of the upper cover is arranged on the conductive disc, and a group of electroplating liquid exchange holes penetrating through the upper cover and the conductive disc are uniformly distributed on the upper cover. The application has the advantages of simple structure, convenient use, realization of double-sided electroplating of a wafer on the basis of a tilted rotary sputtering electroplating process cavity structure, small difference between double-sided electroplating rates, high uniformity, simple operation, strong applicability and the like.

Description

Technical Field

[0001] This invention relates to the field of electroplating tooling, specifically a double-sided electroplating tooling suitable for rotary spraying. Background Technology

[0002] In the field of integrated circuit manufacturing, with the rapid development of 3D stacking technology, especially the requirements for bump metal fabrication, TSV sidewall metal fabrication, and RDL fabrication processes, higher demands are placed on the uniformity and methods of electroplating processes. In silicon-based radio frequency circuits, metal fabrication is typically performed on the sidewalls of vias to form waveguide cavities. To ensure uniform metal thickness on the via sidewalls and reduce the number of electroplating processes, double-sided wafer plating is the optimal process solution.

[0003] Currently, due to the simple structure and ease of modification of rack plating equipment, double-sided wafer electroplating is mainly achieved on rack plating equipment. In rack plating, the plating cathode is located at the center of the process tank, and two anodes are evenly distributed on both sides of the cathode. Because of the cathode loading method in rack plating, the wafer cannot rotate. Therefore, the uniformity of the plated metal layer thickness is poor (7%–10%), which cannot meet the growing demand for double-sided wafer electroplating.

[0004] Existing tilting rotary spraying methods, due to the wafer's self-rotation capability, can significantly improve the uniformity of the electroplated metal layer thickness (≤5%). However, the tilting rotary spraying process has a narrow chamber space and a compact structure, and is mainly used for single-sided wafer electroplating. It presents several problems when used for double-sided electroplating.

[0005] First, in the tilted rotary spraying process chamber, the electroplating cathode needs to be connected to the wafer rotation drive device, making it impossible to add a second anode; second, in the tilted rotary spraying process chamber, there is a difference in the flow rate of the electroplating solution between the back and front areas of the wafer, resulting in an inconsistent electroplating main salt concentration gradient, making it difficult to achieve equal-rate electroplating on both sides of the wafer. Summary of the Invention

[0006] The present invention aims to overcome the shortcomings of the prior art by providing a double-sided electroplating fixture suitable for rotary spraying.

[0007] This application provides the following technical solution:

[0008] A double-sided electroplating fixture suitable for rotary spraying is characterized by: a lower ring body, an upper ring body, and an upper cover being coaxially connected from bottom to top by a set of insulating screws; a lower annular step and a lower annular groove are provided on the lower ring body; a lower conductive ring is installed in the lower annular groove; a set of lower conductive comb teeth are provided on the lower conductive ring; and a set of through holes corresponding to the lower conductive comb teeth are provided on the groove wall of the lower annular groove so that one end of the lower conductive comb teeth extends into the range of the lower annular step.

[0009] The upper ring body is provided with correspondingly distributed annular steps and an upper ring groove. An upper conductive ring is installed in the upper ring groove. A set of upper conductive comb teeth is provided on the upper conductive ring. A set of through holes corresponding to the upper conductive comb teeth is provided on the groove wall of the upper ring groove so that one end of the upper conductive comb teeth can extend into the range of the upper annular step. The upper and lower conductive comb teeth are correspondingly distributed. A conductive post with one end connected to the upper conductive ring is also evenly distributed on the upper ring body. A support cylinder with one end connected to the upper ring body is sleeved on the conductive post.

[0010] A conductive disk is built inside the top cover. A set of conductive leads with one end extending out of the top cover are evenly distributed on the conductive disk. The conductive leads are distributed and matched with the conductive posts. A conductive shaft extending out of the top cover is also provided on the conductive disk. The extended end of the conductive shaft is threaded. A set of electroplating solution exchange holes penetrating the conductive disk are evenly distributed on the top cover.

[0011] The support cylinder and the upper ring are an integral structure, and the lower ring, upper ring, upper cover and support cylinder are made of insulating material.

[0012] Based on the above technical solutions, the following further technical solutions are also possible:

[0013] Upper and lower wafer clamping stages extend from both the lower and upper annular steps.

[0014] Both the lower conductive comb tooth and the upper conductive comb tooth have a 30° bend at one end.

[0015] The conductive disk is provided with a clearance hole that corresponds to the shape of the electroplating solution exchange hole and is enlarged proportionally, so that the clearance hole is covered by the top cover to prevent the conductive disk from being exposed.

[0016] The insulating material is PVDF.

[0017] The electroplating solution exchange holes are comma-shaped through holes, and the pointed tails of a group of electroplating solution exchange holes are skewed in the same direction and at the same angle.

[0018] The thickness of the upper conductive ring is less than the depth of the upper ring groove, and the thickness of the lower conductive ring is greater than the depth of the lower ring groove, so that a part of the lower conductive ring can be inserted into the upper ring groove, and the upper conductive ring and the lower conductive ring come into contact with each other to form a conductive connection between them.

[0019] Advantages of the invention:

[0020] This invention features a simple structure and ease of use. The insulated upper and lower rings possess extremely high mechanical strength, are not easily deformed, and can be used for wafers of various thicknesses. The metal conductive ring structure is simple, easy to replace, and convenient to use. The conductive comb teeth surround the metal conductive strip at equal intervals, providing better support for the wafer. The conductive comb teeth are tilted at a 30° upward ring-pressing wafer clamping structure, increasing the contact pressure between the comb teeth and the wafer and reducing contact resistance. When the tilted rotary spraying double-sided electroplating fixture rotates, the electroplating solution exchange holes can accelerate the flow of the electroplating solution, ensuring wetting of the through holes and maintaining the concentration of the main salt in the electroplating solution. The support cylinder has a certain height, which not only meets the flow of the electroplating solution but also further meets the diffusion of the main salt in the electroplating solution, better maintaining the main salt concentration gradient requirement of the electroplating solution. Based on the tilted rotary spraying electroplating process cavity structure, double-sided electroplating of wafers is realized, which has the advantages of small difference in double-sided electroplating rate, high uniformity, simple operation, and strong applicability. Attached Figure Description

[0021] Figure 1 This is an exploded structural diagram of the present invention;

[0022] Figure 2 A cross-sectional view of the lower ring body in this invention;

[0023] Figure 3 This is a cross-sectional view of the upper ring body in this invention;

[0024] Figure 4 This is a top view of the upper cover in this invention;

[0025] Figure 5 yes Figure 4 AA section view;

[0026] Figure 6 yes Figure 4 BB cross-sectional view. Detailed Implementation

[0027] like Figure 1-6 As shown, a double-sided electroplating fixture suitable for rotary spraying includes a lower ring 1, an upper ring 2, and an upper cover 3 made of the aforementioned insulating material PVDF. These three components are coaxially distributed and have a set of threaded holes a on them. The three components are connected sequentially from bottom to top by inserting corresponding screws (not shown in the figure) through the threaded holes a. These screws have insulating properties. The threaded holes a on the upper cover 3 are countersunk holes.

[0028] A lower annular step 1a is provided on the upper end face of the lower ring body 1, and a lower wafer clamping stage 1c extends from the step surface of the lower annular step 1a. The height of the lower wafer clamping stage 1c is less than the height of the annular step 1a.

[0029] A lower annular groove 1b is provided on one end face of the lower annular body 1 outside the lower annular step 1a. A set of through holes communicating with the annular step 1a are provided on the annular wall of the lower annular groove 1b. There are no through holes at the position of the lower wafer clamping stage 1c.

[0030] A sheet-like, elastic lower conductive ring 4 made of conductive metal is provided. A set of lower conductive comb teeth 4a extends inward from the inner ring surface of the lower conductive ring 4. The lower conductive comb teeth 4a correspond to the through hole so that one end of the lower conductive comb teeth 4a passes through the through hole and extends into the range of the lower annular step 1a. Each end of the lower conductive comb teeth 4a is provided with an upwardly bent angle of 30°.

[0031] The thickness of the lower conductive ring 4 is greater than the depth of the lower ring groove 1b, so that after the lower conductive ring 4 is installed in the ring groove 1b, a portion of its upper end extends out of the ring groove 1b.

[0032] An upper annular step 2a is coaxially distributed on the lower end face of the upper annular body 2. An upper wafer clamping stage (not shown in the figure) extends from the step surface of the upper annular step 2a, corresponding to the lower wafer clamping stage 1c. The height of the upper wafer clamping stage is less than the height of the upper annular step 2a. The upper and lower wafer clamping stages have the same shape so as to clamp the wafers placed between the upper and lower annular bodies.

[0033] An upper annular groove 2b is provided on one end face of the upper annular body 2 outside the upper annular step 2a. A set of through holes communicating with the upper annular step 2a are provided on the annular wall of the upper annular groove 2b. There are no through holes at the upper wafer clamping stage.

[0034] A flexible, sheet-like upper conductive ring 5 made of conductive metal is provided. A set of upper conductive comb teeth 5a extends inward from the inner ring surface of the upper conductive ring 5, corresponding to a through hole. One end of each upper conductive comb tooth 5a passes through the through hole and extends into the area of ​​the upper annular step 2a. Each end of the upper conductive comb tooth 5a has a downwardly bent angle of 30°. The bent angles of the upper and lower conductive comb teeth provide contact pressure to the wafer from both above and below, increasing the contact pressure between the comb teeth and the wafer, thereby reducing contact resistance.

[0035] The thickness of the upper conductive ring 5 is less than the depth of the upper ring groove 2b, so that when the lower ring body 1 and the upper ring body 2 are closed together, the upper end of the lower conductive ring 4 can be inserted into the upper ring groove 2b, thereby realizing the conductive connection between the upper and lower conductive rings 5 ​​and 4.

[0036] A set of conductive posts 5c extending upward from the upper end face of the upper conductive ring 5 extends from the upper ring body 2. A support cylinder 2c connected at one end to the upper ring body 2 is provided on the conductive post 5c. The support cylinder 2c is made of the same material as the upper ring body 2 and is an integral structure with the upper ring body 2. The bottom of the upper ring groove 2b has holes corresponding to the conductive posts 5c.

[0037] A circular top cover 3 is provided, and a conductive disk 6 is built into the top cover 3. A set of conductive leads 6a with one end protruding from the top cover 3 are evenly distributed on the lower surface of the conductive disk 6. The conductive leads 6a are correspondingly distributed and matched with the conductive leads 5c. An insulating ring platform 3b integrally formed with the top cover 3 is also provided on the outer circumference of the conductive leads 6a protruding from the top cover 3.

[0038] A conductive shaft 6b extending from the top cover is provided at the center of the upper surface of the conductive disk 6. A thread 6c is provided at the extended end of the conductive shaft 6b so as to achieve threaded connection with the existing conductive structure of the electroplating equipment, thereby realizing the power connection between the tilting rotation spraying double-sided electroplating fixture and the electroplating equipment.

[0039] A set of electroplating solution exchange holes 7, penetrating the conductive disk 6, are evenly distributed on the upper cover 3. The electroplating solution exchange holes 7 are comma-shaped through holes, and the pointed tails of the set of electroplating solution exchange holes 7 are all skewed in the same direction and angle. A set of clearance holes 6d, corresponding to the shape of the electroplating solution exchange holes 7 and enlarged proportionally, are evenly distributed on the conductive disk 6 so that the clearance holes 6d are covered by the upper cover 3, preventing the conductive disk 6 from being exposed through the clearance holes 6d. Because the electroplating solution exchange holes 7 are comma-shaped, when the device rotates, the electroplating solution passing through the electroplating solution exchange holes 7 can have an acceleration effect, and the electroplating solution can provide a certain liquid flow pressure to the wafer placed between the upper and lower rings from above.

[0040] The upper cover 3 can be a two-piece structure, with the conductive disk 6 embedded inside by interlocking, and then connected by adhesive or heat fusion. Alternatively, the upper cover 3 can be injection molded as a single piece to embed the conductive disk 6 inside.

Claims

1. A double-sided electroplating fixture suitable for rotary spraying, characterized in that: It includes a lower ring body (1), an upper ring body (2) and an upper cover (3) connected coaxially together by a set of insulating screws. The lower ring body (1) is provided with a lower annular step (1a) and a lower annular groove (1b). A lower conductive ring (4) is installed in the lower annular groove (1b). A set of lower conductive comb teeth (4a) is provided on the lower conductive ring (4). A set of through holes corresponding to the lower conductive comb teeth (4a) is provided on the groove wall of the lower annular groove (1b) so that one end of the lower conductive comb teeth (4a) extends into the range of the lower annular step (1a). An annular step (2a) and an upper annular groove (2b) are provided on the upper ring body (2). An upper conductive ring (5) is installed in the upper annular groove (2b). A set of upper conductive comb teeth (5a) is provided on the upper conductive ring (5). A set of through holes corresponding to the upper conductive comb teeth (5a) are provided on the groove wall of the upper annular groove (2b) so that one end of the upper conductive comb teeth (5a) extends into the range of the upper annular step (2a). The upper and lower conductive comb teeth (5a, 4a) are distributed accordingly. A conductive post (5c) with one end connected to the upper conductive ring is also evenly distributed on the upper ring body (2). A support cylinder (2c) with one end connected to the upper ring body (2) is sleeved on the conductive post (5c). The upper cover (3) contains a conductive disk (6), and a set of conductive leads (6a) with one end extending out of the upper cover (3) are evenly distributed on the conductive disk (6). The conductive leads (6a) and the conductive leads (5c) are correspondingly distributed and matched. The conductive disk (6) is also provided with a conductive shaft (6b) extending out of the upper cover. The extended end of the conductive shaft (6b) is provided with a thread (6c). A set of electroplating solution exchange holes (7) penetrating the conductive disk (6) are evenly distributed on the upper cover (3). The support cylinder (2c) and the upper ring (2) are an integral structure. The lower ring (1), the upper ring (2), the upper cover (3) and the support cylinder (2c) are made of insulating material.

2. The double-sided electroplating fixture suitable for rotary spraying as described in claim 1, characterized in that: Upper and lower wafer clamping stages (2c, 1c) extend from both the lower annular step (1a) and the upper annular step (2a).

3. A double-sided electroplating fixture suitable for rotary spraying as described in claim 1, characterized in that: Both the lower conductive comb tooth (4a) and the upper conductive comb tooth (5a) have a 30° bend at one end.

4. A double-sided electroplating fixture suitable for rotary spraying as described in claim 1, characterized in that: The conductive disk (6) is provided with a clearance hole (6d) that corresponds to the shape of the electroplating solution exchange hole (7) and is enlarged proportionally, so that the clearance hole (6d) is covered by the top cover (3) to prevent the conductive disk (6) from being exposed.

5. A double-sided electroplating fixture suitable for rotary spraying as described in claim 1, characterized in that: The insulating material is PVDF.

6. A double-sided electroplating fixture suitable for rotary spraying as described in claim 1, characterized in that: The electroplating solution exchange hole (7) is comma-shaped through hole, and the pointed tails of a group of electroplating solution exchange holes (7) have the same skew direction and angle.

7. A double-sided electroplating fixture suitable for rotary spraying as described in claim 1, characterized in that: The thickness of the upper conductive ring (5) is less than the depth of the upper ring groove (2b), and the thickness of the lower conductive ring (4) is greater than the depth of the lower ring groove (1b), so that a part of the lower conductive ring (4) can be inserted into the upper ring groove (2b), so that the upper conductive ring (5) and the lower conductive ring (4) come into contact with each other to form a conductive connection between them.

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