Wafer fixing device

Abstract

The utility model discloses a wafer fixing device, including electrostatic chuck, compression ring and deposition ring, the electrostatic chuck outside is provided with deposition ring, the electrostatic chuck is located the bottom of wafer, the compression ring is located the top of wafer, the inside diameter of deposition ring is greater than electrostatic chuck outside diameter, the outside diameter of deposition ring is greater than the outside diameter of wafer, the inside diameter of compression ring is less than the outside diameter of wafer, the bottom of electrostatic chuck is provided with heater and motor, the heater is driven under motor, makes the wafer that places on electrostatic chuck ascending movement and with compression ring contact through the screw rod drive mechanism, and the compression ring covers deposition ring completely. The wafer fixing device provided by the utility model can effectively improve and reduce the high warping degree wafer sputtering process difficulty, increase wafer utilization, reduce wafer sticking, back metal pollution and the problem of tip discharge.

Description

Technical Field

[0001] This utility model relates to a wafer fixing device, and more particularly to a wafer fixing device. Background Technology

[0002] In the field of thin film deposition technology, especially in metal sputtering technology, electrostatic chucks play a crucial role in wafer heating and fixation. Metal sputtering is a physical vapor deposition technique that uses an ion beam to bombard a metal target within a vacuum chamber, causing metal atoms to detach from the target surface and deposit onto the wafer to form a metal thin film.

[0003] Metal sputtering processes typically employ electrostatic chucks to hold wafers in place. These chucks apply static charges to the wafer surface, creating an electrostatic attraction between the wafer and the chuck, thus securing the wafer.

[0004] However, when using an electrostatic chuck for metal sputtering, the slightly smaller size of the chuck leads to metal contamination and tip discharge at the wafer edges and back. This can further complicate the sputtering process, especially with wafers exhibiting high warpage, due to the lower adhesion force. Therefore, improvements to existing wafer holding devices are necessary. Utility Model Content

[0005] The technical problem to be solved by this utility model is to provide a wafer fixing device that can effectively reduce the difficulty of high warpage wafer sputtering process, increase wafer utilization, and reduce problems such as wafer sticking, back metal contamination and tip discharge.

[0006] The technical solution adopted by this utility model to solve the above-mentioned technical problems is to provide a wafer fixing device, including an electrostatic chuck, a pressure ring, and a deposition ring. The deposition ring is disposed outside the electrostatic chuck. The electrostatic chuck is located at the bottom of the wafer, and the pressure ring is located above the wafer. The inner diameter of the deposition ring is larger than the outer diameter of the electrostatic chuck, and the outer diameter of the deposition ring is larger than the outer diameter of the wafer. The inner diameter of the pressure ring is smaller than the outer diameter of the wafer. A heater and a motor are disposed at the bottom of the electrostatic chuck. Driven by the motor, the heater causes the wafer placed on the electrostatic chuck to rise and move and contact the pressure ring through a lead screw transmission mechanism, and the pressure ring completely covers the deposition ring.

[0007] Furthermore, the inner surface of the pressure ring consists of a first inner annular surface, an inner conical surface, and a second inner annular surface from top to bottom. The diameter of the second inner annular surface is larger than the diameter of the first inner annular surface. The top of the wafer and the inner conical surface abut each other, and the second inner annular surface and the outer circumferential surface of the deposition ring are in contact.

[0008] Furthermore, the electrostatic chuck is located in the vacuum chamber, and a sealing flange is provided between the heater and the vacuum chamber.

[0009] Furthermore, the pressure ring is locked to the inner surface of the vacuum chamber by fixing screws.

[0010] Furthermore, the wafer has a diameter of 300 mm, the inner circle of the pressure ring has a maximum diameter of 299 mm, the deposition ring has a minimum outer diameter of 297 mm, and the electrostatic chuck has a maximum outer diameter of 297 mm.

[0011] Furthermore, the height of the deposition ring is 12.7 mm.

[0012] Furthermore, the pressure ring is made of stainless steel or aluminum.

[0013] Furthermore, the deposition ring is made of stainless steel.

[0014] Compared with the prior art, the present invention has the following advantages: The wafer fixing device provided by the present invention can not only fix the wafer by the electrostatic attraction of the electrostatic chuck, but also reduce the difficulty of metal sputtering process for high warp wafers by the gravity of the pressure ring, reduce the ineffective edge removal distance of the wafer, and increase the wafer utilization rate; at the same time, the deposition ring can reduce metal film contamination at the edge of the wafer and avoid tip discharge phenomenon. The improved structure can effectively improve the quality and stability of the metal film. Attached Figure Description

[0015] Figure 1 This is a schematic diagram illustrating abnormalities in the edge coating layer caused by wafer warping.

[0016] Figure 2 This is a schematic diagram of the wafer fixing device of this utility model.

[0017] The diagram is marked as follows:

[0018] 1. Wafer 2. Electrostatic chuck 3. Deposition ring

[0019] 4. Curved coating layer; 5. Back coating layer; 6. Tip coating layer

[0020] 7. Tip discharge region; 8. Pressure ring; 9. Vacuum cavity.

[0021] 10 Heater 11 Sealing flange 12 Motor

[0022] 13 Coupling mechanism 14 Screw drive mechanism 15 Fixing screw Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0024] When using an electrostatic chuck for metal sputtering, the chuck's size is slightly smaller than the wafer size, leading to metal contamination and tip discharge at the wafer edges and back. This can increase the difficulty of the sputtering process, especially with wafers exhibiting high warpage due to low adhesion. Please refer to [link to details]. Figure 1 During the coating process of wafer 1, the thin film layer at the edge is an arc-shaped coating layer 4, and a back coating layer 5 is also deposited on the back of the wafer beyond the electrostatic chuck area. This situation is detrimental to subsequent processing because the maximum diameter of the electrostatic chuck 2 is 297mm, while wafer 1 is a standard wafer with a diameter of 300mm. This forces the subsequent processing of wafer 1 to remove a width of approximately 2mm from the edge, which is a significant loss for the chip. Simultaneously, during the coating process of wafer 1, because the outer diameter of the electrostatic chuck 2 is smaller than the diameter of wafer 1, a tip coating layer 6 is also deposited on part of the electrostatic chuck 2. When processing the second wafer, a discharge phenomenon occurs between wafer 1 and the tip coating layer 6, forming a tip discharge region 7.

[0025] To reduce the impact of high warpage wafers on the sputtering process, a pressure ring can be used to suppress wafer warpage; simultaneously, adding a deposition ring can prevent wafer tip discharge issues. Please refer to [link to relevant documentation]. Figure 2 The wafer fixing device provided by this utility model includes an electrostatic chuck 2, a deposition ring 3, and a pressure ring 8. The deposition ring 3 is disposed outside the electrostatic chuck 2. The electrostatic chuck 2 is located at the bottom of the wafer 1. The pressure ring 8 is located above the wafer 1 and is locked to the inner surface of the vacuum chamber 9 by fixing screws 15. The inner diameter of the deposition ring 3 is larger than the outer diameter of the electrostatic chuck 2, and the outer diameter of the deposition ring 3 is larger than the outer diameter of the wafer 2. The inner diameter of the pressure ring 8 is smaller than the outer diameter of the wafer 1. A heater 10 and a motor 12 are disposed at the bottom of the electrostatic chuck 2. The heater 10 is driven by the motor 12, and the wafer 1 placed on the electrostatic chuck 2 is moved upward and moves to contact the pressure ring 8 through a lead screw transmission mechanism 14. The pressure ring 8 completely covers the deposition ring 3 to avoid the formation of tip discharge.

[0026] This invention employs a wafer fixing device combining an electrostatic chuck 2, a deposition ring 3, and a pressure ring 8. During the wafer sputtering process, different parts of the wafer 1 surface are subjected to different ion beam bombardment intensities, affecting the uniformity of the metal film. However, the pressure ring 8 applies uniform gravity to the edge of the wafer 1, thereby limiting the warpage of the wafer 1 and reducing the difficulty of the high warpage wafer sputtering process to a certain extent.

[0027] Specifically, the pressure ring 8 is placed above the wafer 1, with a hollow area in the middle. The pressure ring 8 applies gravity to the wafer 1 to restrict its sliding, thereby suppressing wafer warping during the coating process. At the same time, a deposition ring 3 is added on the electrostatic chuck 2 to completely cover the wafer 1, preventing tip discharge.

[0028] In a preferred embodiment, the inner surface of the pressure ring 8 of this invention consists of a first inner annular surface, an inner conical surface, and a second inner annular surface, from top to bottom. The diameter of the second inner annular surface is larger than the diameter of the first inner annular surface. The wafer 1 abuts against the top of the inner conical surface, and the second inner annular surface fits against the outer circumferential surface of the deposition ring 3. This creates an angular gap between the pressure ring 8 and the wafer 1, which allows for better application of gravity to the wafer and reduces warpage during the process.

[0029] As a preferred embodiment, the deposition ring 3 of this invention has a minimum inner diameter of 297 mm, a deposition ring height of 12.7 mm, and a maximum inner diameter of 299 mm for the pressure ring 8. This ensures that after the sputtering process, the back side of the wafer 1 is free from tip discharge and metal contamination, and the outer edge cut-off width of the wafer is reduced from 2 mm to 0.5 mm, greatly increasing the wafer surface utilization rate.

[0030] Under the action of the motor 12, the bottom heater 10 of this invention raises the wafer 1 placed on the electrostatic chuck 2 to contact the pressure ring 8 through the lead screw transmission mechanism 14. During the wafer metal sputtering process, stress warping occurs. The pressure ring 8 applies pressure evenly to the edge of the wafer to limit the wafer stress warping and reduce the difficulty of metal sputtering for some high warping wafers.

[0031] To improve the strength and manufacturing stability of the components, the pressure ring 8 is made of high-strength materials, such as stainless steel or aluminum. These materials effectively prevent mechanical deformation of the components.

[0032] This invention effectively improves current challenges in wafer sputtering processes through the synergistic effect of an electrostatic chuck, deposition ring, and clamping ring; its specific advantages are as follows:

[0033] ① Reduce the difficulty of metal sputtering process for high warp wafers: The wafer fixing device of this utility model adds the function of pressure ring 8. The electrostatic chuck 2 applies static charge to the surface of wafer 1 to fix wafer 1. Pressure ring 8 applies gravity evenly around wafer 1 to restrict wafer warping, thereby reducing the difficulty of metal sputtering process for high warp wafers.

[0034] ② Reduce metal contamination at wafer edges and on the back side: This invention effectively reduces the arc-shaped metal thin film layer at the wafer edge and the thin film layer that may appear on the back side, reducing adverse effects on subsequent processing.

[0035] ③ Avoid wafer tip discharge: This invention can greatly reduce the occurrence of tip coating layers on the chuck and avoid tip discharge between the thin film layer and the wafer.

[0036] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications and improvements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. A wafer fixing device, characterized in that, The device includes an electrostatic chuck (2) and a pressure ring (8). A deposition ring (3) is provided outside the electrostatic chuck (2). The electrostatic chuck (2) is located at the bottom of the wafer (1). The pressure ring (8) is located above the wafer (1). The inner diameter of the deposition ring (3) is larger than the outer diameter of the electrostatic chuck (2). The outer diameter of the deposition ring (3) is larger than the outer diameter of the wafer (1). The inner diameter of the pressure ring (8) is smaller than the outer diameter of the wafer (1). A heater (10) and a motor (12) are provided at the bottom of the electrostatic chuck (2). The heater (10) is driven by the motor (12) and the wafer (1) placed on the electrostatic chuck (2) is moved upward and in contact with the pressure ring (8) through a screw transmission mechanism (14). The pressure ring (8) completely covers the deposition ring (3).

2. The wafer fixing device as described in claim 1, characterized in that, The inner surface of the pressure ring (8) consists of a first inner ring surface, an inner conical surface, and a second inner ring surface from top to bottom. The diameter of the second inner ring surface is larger than the diameter of the first inner ring surface. The top of the wafer (1) and the inner conical surface abut each other, and the second inner ring surface and the outer circumferential surface of the deposition ring (3) are in contact.

3. The wafer fixing device as described in claim 1, characterized in that, The electrostatic chuck (2) is located in the vacuum chamber (9), and a sealing flange (11) is provided between the heater (10) and the vacuum chamber (9).

4. The wafer fixing device as described in claim 3, characterized in that, The pressure ring (8) is locked to the inner surface of the vacuum chamber (9) by a fixing screw (15).

5. The wafer fixing device as described in claim 1, characterized in that, The wafer (1) has a diameter of 300 mm, the inner circle of the pressure ring (8) has a maximum diameter of 299 mm, the deposition ring (3) has a minimum outer diameter of 297 mm, and the electrostatic chuck (2) has a maximum outer diameter of 297 mm.

6. The wafer fixing device as described in claim 1, characterized in that, The height of the deposition ring (3) is 12.7 mm.

7. The wafer fixing device as described in claim 1, characterized in that, The pressure ring (8) is made of stainless steel or aluminum.

8. The wafer fixing device as described in claim 1, characterized in that, The deposition ring (3) is made of stainless steel.

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