Wafer carrying device and wafer cleaning device using the same

Abstract

This invention provides a wafer carrier device and a wafer cleaning apparatus using the wafer carrier device. The wafer carrier device includes a carrier disk with a carrier surface divided into a central region and an edge region. The central region has a first vent, and the edge region has a second vent. An air cushion layer is provided between the wafer and the carrier surface, formed by gas being blown out through the first and second vents. The advantage of this invention is that, after using the wafer carrier device to carry the wafer for processing, no annular pattern defects will form on the wafer surface.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing, and more particularly to a wafer carrier device and a wafer cleaning device using the wafer carrier device. Background Technology

[0002] In the manufacturing process of semiconductor chips (such as DRAM chips), when atomic layer deposition (ALD) or chemical vapor deposition (CVD) methods are used to deposit film layers, film materials such as silicon oxide, silicon nitride, and polysilicon are deposited on the back side of the wafer. The material deposited on the back side of the wafer may split into layers or peel off during subsequent processes, resulting in defects. It can also affect defocusing and alignment in subsequent photolithography processes and emissivity in rapid annealing processes. Therefore, it is necessary to clean the back side of the wafer to remove the deposited film material.

[0003] Current methods for cleaning the back side of wafers involve applying a chemical solution to the back side to remove the film material deposited thereon. Specifically, Figure 1 This is a schematic diagram of cleaning the back side of a wafer in existing technology. Please refer to... Figure 1 A wafer 10 is placed on a carrier tray 11 with its back side facing up and its patterned front side facing down. Nitrogen gas (N2) is introduced under the wafer using Bernoulli's principle, forming an N2 protective layer 12 on the front side of the wafer 10 to protect the pattern. A chemical solution 13 is sprayed onto the back side of the wafer 10 from above. As the wafer 10 rotates with the carrier tray 11, the chemical solution 13 removes the film material from the back side of the wafer 10. Due to the presence of the N2 protective layer 12, the chemical solution 13 does not flow onto the front side of the wafer 10, thus preventing damage to the pattern on the front side.

[0004] The disadvantage of this method for cleaning the back side of the wafer is that when the temperature of the chemical solution 13 is high (>40°C) and the rotation speed of the carrier disk 11 is high (>1200 rpm), obvious annular pattern defects will be left on the front side of the wafer 10. Figure 2A For a schematic diagram of the front side of the wafer after cleaning, please refer to [link / reference]. Figure 2A A noticeable annular pattern defect 20 is present on the front side of wafer 10. The reason for this annular pattern defect 20 is that during prolonged cleaning, the high-temperature chemical solution causes the wafer 10 and the carrier disk 11 to expand due to heat. During the high-speed rotation of the carrier disk 11, the center of the wafer 10 slightly bends downwards, reducing the distance between the surfaces of the wafer 10 and the carrier disk 11, thus leaving a noticeable annular pattern defect 20 on the front side of the wafer 10. If the distance between the surfaces of the wafer 10 and the carrier disk 11 is too close, causing contact between the surfaces, please refer to [link to relevant documentation]. Figure 2BThe diagram shows the relative positions of the wafer 10 and the carrier disk 11. The wafer 10 will directly contact the protrusion of the carrier disk 11 (as shown by the arrow in the diagram) and produce a ring-shaped scratch. If the distance between the surfaces of the wafer 10 and the carrier disk 11 is relatively close, but the surfaces of the wafer 10 and the carrier disk 11 are not in contact, particles will accumulate on the wafer 10 due to electrostatic adsorption or process reasons, thus producing the ring-shaped dust.

[0005] For the reasons mentioned above, there is a need to provide a wafer carrier device and a wafer cleaning device using the wafer carrier device to overcome the above-mentioned defects. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a wafer carrier device and a wafer cleaning device using the wafer carrier device, which can avoid the formation of scratches on the wafer surface.

[0007] To address the aforementioned problems, the present invention provides a wafer carrier device comprising a carrier disk having a carrier surface divided into a central region and an edge region, wherein a first vent is provided in the central region and a second vent is provided in the edge region, and an air cushion layer is provided between the wafer and the carrier surface, the air cushion layer being formed by gas being blown out through the first vent and the second vent.

[0008] Furthermore, the angle between the centerline of the first vent and the bearing surface is 70° to 90°.

[0009] Furthermore, the number of the first pores is 8 to 16.

[0010] Furthermore, in the central region, the first pores are evenly distributed in a ring shape, and the center of the ring coincides with the center of the central region.

[0011] Furthermore, the bearing surface of the bearing disk has a groove, the central region corresponds to the groove, and the edge region corresponds to the outer region of the groove.

[0012] Furthermore, the edge region surrounds the central region, and in the edge region, the second pores are evenly distributed in a ring, with the center of the ring coinciding with the center of the central region.

[0013] Furthermore, the second pore is distributed in at least two annular layers.

[0014] Furthermore, the angle between the centerline of the second vent and the bearing surface is 30° to 60°.

[0015] Furthermore, the edge of the support disk is provided with a retaining ring that protrudes from the support surface, and the inner sidewall of the retaining ring has a gap with the edge of the wafer placed on the air cushion layer, the gap being 5 to 10 mm.

[0016] Furthermore, the edge of the carrier disk is provided with limiting posts, which limit the movement of the wafer placed on the air cushion layer in the horizontal and vertical directions.

[0017] Furthermore, the limiting post includes a column and a protrusion. The column limits the movement of the wafer in the horizontal direction, and the protrusion limits the movement of the wafer in the vertical direction.

[0018] The present invention also provides a wafer cleaning apparatus, which includes the wafer carrier device as described above.

[0019] The advantage of the wafer carrier device of the present invention is that a first air hole is provided in the central area of ​​the carrier surface of the wafer carrier device, and a second air hole is provided in the edge area. Gas is blown out through the first air hole and the second air hole to form an air cushion layer. The air cushion layer supports the wafer placed on the carrier surface, so that there is a gap between the wafer and the carrier surface, thereby avoiding direct contact or too close distance between the wafer and the carrier surface, and thus avoiding the formation of annular pattern defects on the front side of the wafer during process operations.

[0020] The advantage of the wafer cleaning apparatus of the present invention is that it does not form a ring-shaped pattern defect on the front side of the wafer after cleaning. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of cleaning the back side of a wafer in the prior art;

[0022] Figure 2A This is a schematic diagram of the front side of the wafer after cleaning.

[0023] Figure 2B This is a diagram showing the relative positions of the wafer and the carrier disk;

[0024] Figure 3 This is a schematic top view of the first specific embodiment of the wafer carrier device of the present invention;

[0025] Figure 4 It is along Figure 3 Schematic diagram of the cross section of line AA;

[0026] Figure 5 This is a schematic diagram of a wafer carrier device of the present invention carrying a wafer;

[0027] Figure 6 This is a schematic top view of another specific embodiment of the wafer carrier device of the present invention;

[0028] Figure 7 This is a schematic top view of another specific embodiment of the wafer carrier device of the present invention;

[0029] Figure 8 This is a schematic top view of the second specific embodiment of the wafer carrier device 3 of the present invention;

[0030] Figure 9 It is along Figure 8 Schematic diagram of the cross section of line AA;

[0031] Figure 10 This is a partial schematic diagram of the wafer edge during the cleaning of the back side of the wafer;

[0032] Figure 11 This is a schematic top view of the third specific embodiment of the wafer carrier device of the present invention;

[0033] Figure 12 It is along Figure 11 Schematic diagram of the cross section of line AA;

[0034] Figure 13 This is a schematic diagram of a specific embodiment of a wafer cleaning apparatus. Detailed Implementation

[0035] The following detailed description, with reference to the accompanying drawings, provides a specific embodiment of the wafer carrier device and the wafer cleaning device using the present invention.

[0036] The wafer carrier device of the present invention can be used to carry wafers during wafer cleaning, and also to carry wafers during other operations on the wafer surface. In the following detailed description of embodiments, the wafer carrier device is used as an example of carrying wafers during wafer cleaning.

[0037] Figure 3 This is a schematic top view of the first specific embodiment of the wafer carrier device 3 of the present invention. Figure 4 It is along Figure 3 A schematic diagram of the cross-section of line AA. Please refer to [link / reference]. Figure 3 and Figure 4 The wafer carrier device 3 includes a carrier disk 30, which has a carrier surface 30A. Figure 5 This is a schematic diagram of a wafer carrier device of the present invention carrying a wafer. Please refer to [link / reference]. Figure 5 The wafer 100 is placed on the support surface 30A. In order to clean the back side of the wafer 100, the wafer 100 can be placed face down on the support surface 30A of the support disk 30.

[0038] The bearing surface 30A is divided into a central region C and an edge region D. Figure 3 The edge region D is depicted using a shaded line. The radius of the central region C is less than two-thirds of the radius of the bearing surface 30A. In this specific embodiment, the edge region D surrounds the central region C, that is, the edge region D is positioned along the edge of the central region C, and the central region C and the edge region D together form the bearing surface 30A. For other specific embodiments of the present invention, please refer to... Figure 6 The edge region D is located at the edge of the bearing surface 30A, and the center region C is located at the center of the bearing surface 30A. There is a gap between the edge region D and the center region C. Figure 6 In the diagram, dashed lines are used to represent the boundary between the central region C and the edge region D.

[0039] A first vent 31 is provided in the central region C, and a second vent 32 is provided in the edge region D. In this specific embodiment, multiple first vents 31 are provided in the central region C, and multiple second vents 32 are provided in the edge region D. External gas is blown out through the first vents 31 and the second vents 32, and the gas flow direction is as follows: Figure 5 As indicated by the middle arrow. The external gas includes, but is not limited to, nitrogen.

[0040] An air cushion layer 33 is provided between the wafer 100 and the supporting surface 30A. The air cushion layer 33 is formed by external gas being blown out through the first air hole 31 and the second air hole 32. The air cushion layer 33 can support the wafer 100 placed on the supporting surface 30A, so that there is a gap between the wafer 100 and the supporting surface 30A. That is, when external gas is blown out through the first air hole 31 and the second air hole 32 to form the air cushion layer 33, the front side of the wafer 100 is not in direct contact with the supporting surface 30A. When the external gas flow rate is constant, the air cushion layer 33 can fix the wafer 100 in a set position.

[0041] When the wafer carrier holds the wafer 100 during wafer cleaning, and the chemical solution is sprayed from above the back side of the wafer 100, the air cushion layer 33 can act as a barrier layer to prevent the chemical solution from entering the front side of the wafer 100, thereby protecting the pattern on the front side of the wafer from being damaged.

[0042] After the wafer 100 and wafer carrier 3 are deformed, for example, after the wafer 100 and wafer carrier 3 are thermally expanded, in the central region C, due to the support of the gas blown out by the first vent 32 on the middle part of the wafer 100, the middle part of the wafer 100 will not sink downward. Therefore, the distance between the middle part of the wafer 100 and the carrier surface 30A will not decrease, thereby avoiding the situation where the front side of the wafer 100 directly contacts the carrier surface 30A, or avoiding the situation where particles accumulate on the front side of the wafer 100 due to the distance between the middle part of the wafer 100 and the carrier surface 30A being too close. Thus, no annular pattern defects will form on the front side of the wafer 100. If the flow rate of the external gas is increased, the center of the wafer 100 can protrude upwards, thereby further increasing the distance between the wafer 100 and the supporting surface 30A. This further prevents direct contact between the wafer 100 and the supporting surface 30A and the accumulation of particles on the wafer 100, thus ensuring that no annular pattern defects form on the front side of the wafer 100. The flow rate of the external gas can be between 100-200 L / min, allowing the air cushion layer 33 to provide good support for the wafer 100.

[0043] Furthermore, the first vents 31 are evenly distributed in a ring shape in the central region C, with the center of the ring coinciding with the center of the central region C; the second vents 32 are evenly distributed in a ring shape in the edge region D, with the center of the ring coinciding with the center of the central region C. This distribution provides uniform support for the wafer 100, preventing the wafer 100 from tilting. Preferably, the number of the first vents 31 is 8 to 16. This range of the number of first vents 31 allows external gas to provide better support for the center of the wafer 100, preventing the wafer 100 from contacting the bearing surface 30A, and also preventing the wafer 100 from being lifted too high and causing it to veer out of the wafer bearing device.

[0044] Preferably, the angle between the centerline of the first vent 31 and the bearing surface 30A is 70° to 90°. In this specific embodiment, the angle α between the centerline of the first vent 31 (as shown by the dotted line in the figure) and the bearing surface 30A is 90°, that is, the centerline of the first vent 31 is perpendicular to the bearing surface 30A, and external gas is blown out vertically from the first vent 31 to improve the support of the air cushion layer 33 for the wafer 100. In other specific embodiments of the present invention, the angle between the centerline of the first vent 31 and the bearing surface 30A can be 70° or 80°, etc., and external gas is blown out obliquely from the first vent 31.

[0045] Furthermore, the bearing surface 30A of the bearing disk 30 has a groove 301. The groove 301 is recessed towards the interior of the bearing disk 30. The arrangement of the first vent 31 in the central region C needs to ensure that the center of the wafer 100 does not contact the edge of the groove 301 when external gas is introduced. In this specific embodiment, the central region C corresponds to the groove 301, the edge region D corresponds to the outer region of the groove 301, the first vent 31 is disposed on the bottom surface of the groove 301, and the second vent 32 is disposed in the outer region of the groove 301. For other specific embodiments of the present invention, please refer to... Figure 7 The central region C covers the groove 301, and the first air hole 31 is disposed around the groove 301.

[0046] For further information, please refer to [link / reference]. Figure 3 , Figure 4 and Figure 5 The edge of the carrier disk 30 is provided with a limiting post 302, which limits the movement of the wafer 100 placed on the carrier surface 30A and the air cushion layer 33 in the horizontal and vertical directions, thereby preventing the wafer 100 from detaching from the wafer carrier device 3.

[0047] The limiting post 302 can limit the wafer 100 by rotating itself or moving relative to the bearing surface 30A.

[0048] For asymmetrically shaped positioning posts, when the wafer is not placed on the bearing surface 30A, one side of the positioning post serves as the inner side. In this case, the gap defined by the positioning post is relatively large, which facilitates wafer placement. When the wafer is placed on the bearing surface 30A, the positioning post rotates so that its other side serves as the inner side. In this case, the gap defined by the positioning post is relatively small, and it can contact the edge of the wafer, thereby limiting the horizontal and vertical movement of the wafer.

[0049] For the limiting post that can move relative to the bearing surface 30A, when the wafer is not placed on the bearing surface 30A, the limiting post 302 is located on the outermost side. In this case, the gap in the area defined by the limiting post is large, which makes it easier to place the wafer. When the wafer is placed on the bearing surface 30A, the limiting post 302 moves inward relative to the bearing surface 30A and can contact the edge of the wafer. In this case, the gap in the area defined by the limiting post is small, thereby limiting the movement of the wafer in the horizontal and vertical directions.

[0050] In this specific embodiment, the limiting post 302 includes a post 302A and a protrusion 302B connected to the post 302A. The protrusion 302B can be an integral structure with the post 302A, or it can be another component connected to the post 302A. In this specific embodiment, the protrusion 302B is an integral structure with the post 302A.

[0051] When the limiting post 302 limits the wafer 100, the pillar 302A contacts the side edge of the wafer 100, limiting the horizontal movement of the wafer 100, and the protrusion 302B is located above the back edge of the wafer 100, limiting the vertical movement of the wafer 100. In this specific embodiment, the limiting post 302 can be moved from the outside to the inside, thereby causing the pillar 302A to contact the side edge of the wafer 100, and the protrusion 302B to be located above the back edge of the wafer 100.

[0052] The present invention also provides a second embodiment of the wafer carrier device 3. The difference between the second embodiment and the first embodiment is that, in the edge region D, the second vent 32 is distributed in at least two layers of annular shape. Figure 8 This is a schematic top view of the second specific embodiment of the wafer carrier device 3 of the present invention. Figure 9 It is along Figure 8 Please refer to the cross-sectional diagram of line AA. Figure 8 and Figure 9 In the second specific embodiment, the second vent 32 is distributed in a two-layer annular shape, that is, in the edge region D, the second vent 32 is distributed as an inner annular layer 32A and an outer annular layer 32B. The second vent 32 is arranged in multiple annular layers, which can make the airflow of external gas introduced under the entire bearing surface 30A more uniform and stable, and reduce the shaking of the wafer 100 relative to the bearing disk 30.

[0053] Additionally, please see Figure 10 This is a partial schematic diagram of the wafer edge during cleaning of the back side of wafer 100. The second air hole 32 is arranged in a multi-layered annular pattern. External gas blown onto the front side of wafer 100 moves towards the edge of wafer 100, that is, the area of ​​the air cushion layer 33 increases. This increases the coverage area of ​​the air cushion layer 33 over the front edge of wafer 100. Therefore, when cleaning the back side of wafer 100, the cleaning area of ​​the chemical solution 300 on the front edge of the wafer is reduced, and the range of the film layer removed by the chemical solution 300 on the front edge of the wafer is reduced, thus improving the control accuracy of the range of the wafer edge removal area. Specifically, when the wafer carrier device of this invention is used to carry the wafer during wafer cleaning, the width of the wafer front edge removal area can be controlled within 0.3 mm.

[0054] Preferably, in this second specific embodiment, the center line of the second vent 32 located in the outer annular layer 32B (e.g., Figure 9 The angle β between the air cushion layer 33 (shown by the dashed line) and the bearing surface 30A is 30° to 60°, which can further increase the coverage area of ​​the air cushion layer 33 on the front side of the wafer, thereby better protecting the front side of the wafer and preventing its pattern from being removed by the chemical solution. Preferably, the number of second pores 32 of the outer annular layer 32B is 20 to 40, so as to further increase the coverage area of ​​the air cushion layer 33 on the front side of the wafer.

[0055] To further prevent external liquids (e.g., chemical solutions) from entering the front side of the wafer from the edge, the present invention provides a retaining ring protruding from the bearing surface 30A at the edge of the bearing disk 30. Figure 11 This is a schematic top view of the third specific embodiment of the wafer carrier device 3 of the present invention. Figure 12 It is along Figure 11 Please refer to the cross-sectional diagram of line AA. Figure 11 and Figure 12 The difference between the third and first embodiments lies in that a retaining ring 34 protruding from the bearing surface 30A is provided at the edge of the bearing disk 30, and the retaining ring 34 surrounds the edge of the bearing disk 30. A gap exists between the inner wall of the retaining ring 34 and the edge of the wafer 100 placed on the air cushion layer 33. This gap prevents the retaining ring 34 from contacting the wafer 100, facilitating the placement of the wafer 100 on the air cushion layer 33. When external liquid is sprayed from the back of the wafer 100, the retaining ring 34 can block the external liquid, greatly reducing the volume of external liquid entering the gap between the retaining ring 34 and the edge of the wafer. This makes it difficult for external liquid to contact the front of the wafer, thereby improving the protection of the front of the wafer and further reducing the area of ​​the edge removal region on the front of the wafer.

[0056] Preferably, the gap between the inner wall of the retaining ring 34 and the edge of the wafer 100 is in the range of 5 to 10 mm. When the size of the gap is within this range, the volume of external liquid entering the front side of the wafer can be reduced without affecting the placement of the wafer 100.

[0057] The present invention also provides a wafer cleaning apparatus that uses the above-described wafer carrier device to carry the wafer. Figure 13 This is a schematic diagram of a specific embodiment of the wafer cleaning apparatus. Please refer to [link / reference]. Figure 13The wafer cleaning apparatus includes a wafer carrier 3 and a chemical solution spraying device 4 as described above. The chemical solution spraying device 4 is positioned above the wafer carrier 3, on which the wafer is placed. When cleaning is required, the chemical solution spraying device 4 sprays a chemical solution, which acts on the back side of the wafer to remove the film material on the back side. After cleaning the wafer, this wafer cleaning apparatus can prevent the leaving of annular pattern defects on the front side of the wafer.

[0058] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A wafer carrier device, characterized in that, The device includes a carrier disk having a carrier surface divided into a central region and an edge region. The central region is provided with a first vent, and the edge region is provided with a second vent. An air cushion layer is provided between the wafer and the carrier surface, and the air cushion layer is formed by blowing gas through the first vent and the second vent. Wherein, the angle between the centerline of the first air hole and the bearing surface is 70°~90°; the bearing surface of the bearing plate has a groove, the central region corresponds to the groove, and the edge region corresponds to the outer region of the groove; the angle between the centerline of the second air hole and the bearing surface is 30°~60°.

2. The wafer carrier device according to claim 1, characterized in that, The number of the first pores is 8 to 16.

3. The wafer carrier device according to claim 1, characterized in that, In the central region, the first pores are evenly distributed in a ring, and the center of the ring coincides with the center of the central region.

4. The wafer carrier device according to claim 1, characterized in that, The edge region surrounds the central region, and in the edge region, the second pores are evenly distributed in a ring, with the center of the ring coinciding with the center of the central region.

5. The wafer carrier device according to claim 4, characterized in that, The second pore is distributed in at least two annular layers.

6. The wafer carrier device according to claim 1, characterized in that, The edge of the support disk is provided with a retaining ring that protrudes from the support surface. The inner sidewall of the retaining ring has a gap with the edge of the wafer placed on the air cushion layer, and the gap ranges from 5 to 10 mm.

7. The wafer carrier device according to claim 1, characterized in that, The edge of the carrier disk is provided with a limiting post, which limits the movement of the wafer placed on the air cushion layer in the horizontal and vertical directions.

8. The wafer carrier device according to claim 7, characterized in that, The limiting post includes a column and a protrusion. The column limits the movement of the wafer in the horizontal direction, and the protrusion limits the movement of the wafer in the vertical direction.

9. A wafer cleaning apparatus, characterized in that, Includes the wafer carrier device as described in any one of claims 1 to 8.

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