An elevator ejection pin assembly and a plasma reaction apparatus

Abstract

The application provides a lift pin assembly used in a vacuum reaction chamber, the vacuum reaction chamber comprising a pedestal and an electrostatic chuck, each through hole on the pedestal and a corresponding through hole on the electrostatic chuck forming a vertical channel, the lift pin assembly comprising: a lift pin used for lifting a wafer through the corresponding channel to separate the wafer from the surface of the electrostatic chuck; a sleeve fixedly connected below the pedestal and corresponding to the position of the channel where the lift pin is located; a first flange arranged in the sleeve and in clearance fit with the sleeve, the bottom of the lift pin being fixedly connected with the first flange; the first flange being driven by a driving device to move up and down in the sleeve; and a plurality of conductive elastic devices elastically connected between the outer wall of the first flange and the inner wall of the sleeve to make the first flange and the sleeve have the same electric potential. The application also provides a plasma reaction device. The lift pin assembly of the application can prevent discharge and sparking in a radio frequency environment.

Description

Technical Field

[0001] This invention relates to the field of plasma etching technology, and more particularly to a lifting pin assembly and plasma reaction device for preventing discharge under high radio frequency power. Background Technology

[0002] Currently, processes such as plasma etching, physical vapor deposition, and chemical vapor deposition are commonly used for microfabrication of semiconductor components or wafers, for example, in the manufacture of flexible displays, flat panel displays, light-emitting diodes, and solar cells. Different steps in microfabrication may include plasma-assisted processes, which are typically performed within the vacuum reaction chamber of a plasma processing apparatus. To ensure the uniformity of the processed wafers, they must be placed horizontally to guarantee process uniformity. Additionally, the cleanliness of the vacuum reaction chamber must be maintained to prevent wafer contamination.

[0003] Traditional plasma processing equipment typically includes: a vacuum reaction chamber containing a base for supporting a wafer, and an electrostatic chuck on the base for placing the wafer to be processed. During plasma processing, the wafer is first placed on the electrostatic chuck, where oppositely polarized electrostatic charges are generated between the chuck and the wafer, creating an electrostatic attraction force. The wafer is held or fixed by the electrostatic attraction force of the chuck. A patterned microelectronic layer is formed on the wafer. Radio frequency energy is emitted into the vacuum reaction chamber through a radio frequency power transmitter to form a radio frequency electric field; then, various reactive gases (etching gases or deposition gases) are injected into the vacuum reaction chamber, and under the action of the radio frequency electric field, the injected reactive gases are excited into a plasma state above the wafer; finally, chemical reactions and / or physical interactions (such as etching, deposition, etc.) occur between the plasma and the wafer, forming various characteristic structures. Volatile reaction products formed during the chemical reaction detach from the surface of the etched material and are extracted from the vacuum reaction chamber by the vacuum system.

[0004] To meet process requirements, not only is strict control of the wafer handling process necessary, but also wafer loading and unclamping, which are critical steps in wafer processing. Both the base and the electrostatic chuck have several through-holes. Each through-hole on the base and its corresponding through-hole on the electrostatic chuck form a vertical channel. Some channels are used to accommodate vertically positioned lifting pins, which pass through their corresponding channels to contact the back of the wafer.

[0005] A lifting mechanism is usually fixedly connected below the ejector pin to enable its vertical movement. As the radio frequency voltage applied to the vacuum reaction chamber increases, ignition can easily occur within the lifting mechanism. Furthermore, since the upper and lower ends of the lifting mechanism are connected to the vacuum environment inside the reaction chamber and the external atmospheric environment, respectively, achieving absolute isolation between the vacuum environment and the atmospheric environment through the lifting mechanism is another crucial issue that needs to be considered. Summary of the Invention

[0006] The purpose of this invention is to provide a lifting pin assembly and a plasma reaction device. By setting several conductive elastic devices on the lifting pin assembly, the discharge arcing of the lifting pin assembly in the radio frequency field environment can be prevented. This reduces the friction generated during the up-and-down movement of the lifting pin assembly, effectively reduces the wear of the lifting pin assembly, and improves the wafer yield and the service life of the lifting pin assembly.

[0007] To achieve the above objectives, the present invention provides a lifting pin assembly for use in a vacuum reaction chamber. The vacuum reaction chamber includes a base, and an electrostatic chuck for placing a wafer is provided above the base. Both the base and the electrostatic chuck have several through holes. Each through hole on the base and the corresponding through hole on the electrostatic chuck form a vertical channel. The lifting pin assembly includes:

[0008] Lifting pins are used to lift the wafer through the corresponding channels to separate the wafer from the surface of the electrostatic chuck.

[0009] The sleeve is fixedly connected below the base and corresponds to the channel position where the lifting pin is located.

[0010] The first flange is disposed inside the sleeve and is clearance-fitted with the sleeve. The bottom of the lifting pin is fixedly connected to the first flange. The first flange is driven to move up and down inside the sleeve by a driving device.

[0011] Several conductive elastic devices are elastically connected and disposed between the outer wall of the first flange and the inner wall of the sleeve to achieve equipotential between the first flange and the sleeve.

[0012] Optionally, the elastic device has an arcuate surface that protrudes toward the first flange and abuts against the outer wall of the first flange.

[0013] Optionally, the inner wall of the sleeve is provided with several mounting holes, each used to install a corresponding elastic device.

[0014] Optionally, the elastic device is an arc-shaped first spring; both ends of the first spring are disposed in the mounting hole and abut against the inner wall of the mounting hole; the arc-shaped surface in the middle of the first spring protrudes from the mounting hole and abuts against the outer wall of the first flange; when the first flange moves up and down, the first spring slides and connects to the first flange.

[0015] Optionally, the elastic device includes: an arc-shaped first spring and a ball bearing that matches the mounting hole;

[0016] The first spring is disposed in the mounting hole and remains in a deformed state; the arc-shaped surface of the first spring protrudes from the first flange, and the distance between the two ends of the first spring is greater than the distance between its two ends in its natural state.

[0017] The ball bearing is disposed in the mounting hole and located between the arc-shaped surface of the first spring and the outer wall of the first flange; the ball bearing is squeezed by the deformation restoring force of the first spring, so that the ball bearing extends out of the mounting hole and abuts against the outer wall of the first flange; when the first flange moves up and down, the ball bearing rolls and connects to the first flange.

[0018] Optionally, the elastic device further includes an arc-shaped second spring and a third spring; the second and third springs are disposed in the mounting hole, with the arc-shaped surface of the second spring convex downward and the arc-shaped surface of the third spring convex upward, and a ball is disposed between the second and third springs and abuts against the arc-shaped surfaces of the second and third springs.

[0019] Optionally, a second flange is also fixedly provided on the top end face of the sleeve; a mounting plate is provided below the base, and the top end of the sleeve and the second flange are both located inside the mounting plate.

[0020] Optionally, the lifting pin assembly further includes a bellows corresponding to the channel position; the top and bottom ends of the bellows are respectively fixedly connected to the bottom surface of the second flange and the top surface of the first flange; the bottom of the lifting pin is located inside the bellows.

[0021] Optionally, the plurality of conductive elastic devices are distributed uniformly or non-uniformly on both sides of the first flange.

[0022] Optionally, the first to third elastic springs may be made of either copper alloy or silver-copper alloy.

[0023] Optionally, the bellows, the first flange, and the second flange are made of stainless steel, and the sleeve is made of copper.

[0024] Optionally, the balls are made of stainless steel and have a conductive coating on their outer surface.

[0025] Optionally, the conductive coating may include either a graphene coating or an MXene coating.

[0026] Optionally, the top end of the lifting pin is provided with a disc-shaped structure, the diameter of which is larger than the diameter of the lifting pin but smaller than the diameter of the through hole.

[0027] Optionally, the drive device may include any one of a cylinder, a motor, or a hydraulic cylinder.

[0028] The present invention also provides a plasma reaction apparatus, which includes a vacuum reaction chamber containing a base. An electrostatic chuck for placing a wafer is provided above the base. Both the base and the electrostatic chuck have a plurality of through holes. Each through hole on the base and a corresponding through hole on the electrostatic chuck form a vertical channel. The plasma reaction apparatus includes:

[0029] Multiple lifting pin assemblies as described in this invention.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] 1) Several conductive springs are provided between the sleeve and the first flange of the lifting pin assembly of the present invention. The springs achieve good electrical contact between the sleeve and the first flange, so that the sleeve and the first flange always maintain the same potential. This prevents the sleeve and the first flange from generating a potential difference in the radio frequency field environment, which would cause discharge arcing or welding. This effectively reduces the generation of contaminants and ensures the stability of the electrostatic chuck, ensuring the yield of wafers and improving the service life of the lifting pin assembly.

[0032] 2) The present invention has multiple mounting holes on the inner wall of the sleeve. A ball bearing and at least one spring are installed in the mounting holes. The spring squeezes the ball bearing, causing it to extend out of the mounting hole and abut against the outer wall of the first flange, ensuring good electrical connection between the ball bearing and the first flange, so that the sleeve and the first flange always maintain the same potential. The ball bearing rolls to connect the first flange, changing the surface contact between the first flange and the sleeve to a point contact between the first flange and the ball bearing. The sliding friction between the first flange and the sleeve is changed to the rolling friction between the first flange and the ball bearing, which significantly reduces the wear of the sleeve and the first flange. It effectively avoids the misalignment of the sleeve and the first flange caused by wear, which may cause the lifting pin to jam during the lifting process, and further improves the service life of the lifting pin assembly.

[0033] 3) This invention reduces the metal precipitates generated by the sleeve and the first flange during friction, and effectively isolates the vacuum environment and atmospheric environment in the reaction chamber through the bellows, preventing the metal precipitates from entering the reaction chamber, thereby effectively improving the wafer yield.

[0034] 4) This invention applies pressure to the ball bearing from multiple directions using multiple springs to prevent a loose connection between the ball bearing and the first flange, further ensuring the stability of the electrical connection between the ball bearing and the first flange, and effectively avoiding discharge arcing between the sleeve and the first flange in a radio frequency field environment.

[0035] 5) The present invention uses a ball bearing to connect the first flange, which greatly reduces the friction between the ball bearing and the first flange and avoids the sleeve and the first flange from being too tight. Therefore, the present invention can further reduce the clearance of the tolerance fit between the sleeve and the first flange, improve the concentricity between the first flange and the sleeve during the up and down movement, and avoid the lifting pin from getting stuck during the lifting process. Attached Figure Description

[0036] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description will be briefly introduced below. Obviously, the drawings described below are one embodiment of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort:

[0037] Figure 1 A schematic diagram of a plasma reaction device without using the lifting pin assembly of the present invention;

[0038] Figure 2 Schematic diagram of discharge and ignition for the ejector pin lifting mechanism;

[0039] Figure 3 This is a schematic diagram of the plasma reaction device of the present invention;

[0040] Figure 4 This is a schematic diagram of the lifting pin assembly of the present invention in Embodiment 1;

[0041] Figure 4A for Figure 4 A magnified view of a portion of the image;

[0042] Figure 5 This is a schematic diagram of the lifting pin assembly of the present invention in Embodiment 2;

[0043] Figure 6 This is a schematic diagram of the lifting pin assembly of the present invention in Embodiment 3;

[0044] Figure 6A for Figure 6 A magnified view of a portion of the image;

[0045] Figure 7 This is a schematic diagram of the lifting pin assembly of the present invention in Embodiment 4;

[0046] Figure 7A for Figure 7 A partially enlarged schematic diagram. Detailed Implementation

[0047] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] Figure 1 A plasma processing apparatus prior to using the lifting pin assembly of the present invention is shown. The plasma processing apparatus 1 shown has a reaction chamber 10, which is substantially cylindrical with substantially vertical sidewalls. The reaction chamber 10 has an upper electrode 11 and a lower electrode 13 arranged parallel to each other. Typically, the region between the upper electrode 11 and the lower electrode 13 is a processing region A, which generates high-frequency energy to ignite and sustain the plasma. The lower electrode 13 includes a base 131, on which is an electrostatic chuck 1311 for placing the wafer W to be processed. The electrostatic chuck 1311 has electrodes 1312 for generating electrostatic forces. A reactive gas is input into the reaction chamber 10 from a gas source 12. One or more radio frequency (RF) power supplies 14 can be applied individually to the lower electrode 13 or simultaneously to both the upper electrode 11 and the lower electrode 13 to deliver RF power to the lower electrode 13 or both the upper and lower electrodes 13, thereby generating a large electric field inside the reaction chamber 10. Most of the electric field is contained within the processing region A between the upper electrode 11 and the lower electrode 13. This electric field accelerates a small number of electrons present inside the reaction chamber 11, causing them to collide with the gas molecules of the input reactive gas. These collisions lead to the ionization of the reactive gas and the excitation of the plasma, thereby generating plasma within the reaction chamber 10. Neutral gas molecules of the reactive gas lose electrons when subjected to these strong electric fields, leaving behind positively charged ions. These positively charged ions are accelerated towards the lower electrode 13 and combine with the neutral material in the wafer W being processed, exciting wafer W processing, i.e., etching, deposition, etc. An exhaust region is provided at a suitable location in the plasma processing apparatus 1. The exhaust region is connected to an external exhaust device (e.g., a vacuum pump 15) to extract the used reactive gas and byproduct gas from the processing region A during the processing, establishing appropriate pressure within the processing region A through gas flow.

[0049] Both the base 131 and the electrostatic chuck 1311 have several through holes. Each through hole on the base 131 and the corresponding through hole on the electrostatic chuck 1311 form a vertical channel. Some channels are used to accommodate vertically positioned lifting pins, which pass through the corresponding channels to contact the back side of the wafer. Before the process begins, a robotic arm outside the reaction chamber transfers the wafer W into the reaction chamber and places it on a lifting pin that rises from the electrostatic chuck 1311. During the process, the lifting pin descends, supported and adsorbed by the electrostatic chuck 1311. After the process is complete, the top of the lifting pin rises from the upper surface of the electrostatic chuck and lifts the wafer W, separating the wafer W from the electrostatic chuck 1311. At this point, the robotic arm outside the reaction chamber inserts between the wafer W and the electrostatic chuck 1311 to unload the wafer.

[0050] like Figure 2 As shown, a lifting mechanism 16 is typically fixedly connected below the lifting pin 161 to enable the vertical movement of the lifting pin 161. This lifting mechanism 16 includes a vertically fixed sleeve 162, a first flange 163 embedded within the sleeve 162 (the sleeve 162 is the stator, and the first flange 163 is the mover), and a bellows 164 connecting the sleeve 162 and the first flange 163. The sleeve 162 corresponds to the channel position, and the bottom of the lifting pin 161 is located within the sleeve 162 and fixedly connected to the first flange 163. By driving the first flange 163 to move up and down along the axial direction of the sleeve 162, the top of the lifting pin can be raised from the upper surface of the electrostatic chuck or retracted into the electrostatic chuck.

[0051] The radio frequency (RF) power applied to the base 131 generates an RF field within the vacuum reaction chamber, placing the ejector pin lifting mechanism 16 within this RF field. Both the sleeve 162 and the first flange 163 are made of metal; ideally, the sleeve 162 and the first flange 163 are concentric and not in contact. In the RF field environment, the sleeve 162 and the first flange 163 are equivalent to a large capacitor. After the RF signal propagates from the outer surface of the sleeve to the inner surface, it continues to propagate in two paths: the first path propagates upwards along the inner surface of the sleeve; the second path is capacitively coupled to the first flange 163 through the sleeve 162 and then propagates upwards along the bellows 164. Since the bellows 164 is equivalent to a large inductor, the impedance of the second path is greater than that of the first path, resulting in a potential difference between the sleeve 162 and the first flange 163.

[0052] Because the first flange 163 and the sleeve 162 have a clearance fit, when the first flange 163 slides inside the sleeve 162, it will have unstable short-term contact with the inner wall of the sleeve. At the contact point ( Figure 2The potential difference (shown by the dashed circle) drops instantaneously, making it prone to arcing at the contact point. This causes RF signal disturbances / fluctuations and generates particulate matter, increasing friction between the first flange 163 and the sleeve 162, eventually leading to jamming. Simultaneously, the localized high temperatures generated by arcing can cause the sleeve 162 to oxidize and discolor. In severe cases, the high temperature can weld the sleeve 162 to the first flange 163, greatly threatening the stability and safety of the electrostatic chuck 1311. Therefore, a solution is urgently needed to meet the demands of high RF power.

[0053] like Figure 2 As shown, the tolerance clearance d between the first flange 163 and the sleeve 162 is set between 0.015mm and 0.036mm. If the clearance d is too large, the first flange 163 will easily swing laterally within the sleeve 162, causing misalignment between the first flange 163 and the sleeve 162, resulting in jamming of the first flange 163 and wear on both the first flange 163 and the sleeve 162. In actual use, due to wear on the first flange 163 and the sleeve 162, the tolerance clearance d between the first flange 163 and the sleeve 162 may exceed 0.04mm. Therefore, the first flange 163 is more likely to swing laterally within the sleeve 162, making unstable short-term contact between the first flange 163 and the inner wall of the sleeve more likely. When the tolerance clearance d between the first flange 163 and the sleeve 162 is too small, the sliding friction between the first flange 163 and the sleeve 162 will increase, also causing jamming of the first flange 163 and wear on both the first flange 163 and the sleeve 162. Wear between the first flange 163 and the sleeve 162 can cause metal precipitation. How to reduce metal precipitation and prevent it from entering the reaction chamber is also a current problem.

[0054] Example 1

[0055] This invention provides a lifting pin assembly 26, such as Figure 3 As shown, this is used in a vacuum reaction chamber, which includes a base 231. Above the base 231 is an electrostatic chuck 2311 for placing a wafer W. The electrostatic chuck 2311 contains electrodes 2312 for generating electrostatic force. Both the base 231 and the electrostatic chuck 2311 have several through holes, and each through hole on the base 231 and the corresponding through hole on the electrostatic chuck 2311 form a vertical channel.

[0056] like Figure 4 As shown, the lifting pin assembly 26 includes: a lifting pin 261, a sleeve 262, a first flange 263, several conductive first springs 266, a second flange 265, and a bellows 264.

[0057] The lifting pin 261 is used to lift the wafer W through the corresponding channel, thereby separating the wafer W from the surface of the electrostatic chuck; for example Figure 4As shown, optionally, the top end of the lifting pin 261 is provided with a disk-shaped structure 2611. The diameter of the disk-shaped structure 2611 is larger than the diameter of the lifting pin and smaller than the diameter of the through hole. The disk-shaped structure 2611 can achieve more stable support of the wafer W.

[0058] The sleeve 262 is fixedly connected to the bottom of the base and corresponds to the channel position where the lifting pin 261 is located;

[0059] The first flange 263 is disposed inside the sleeve 262 and is clearance-fitted with the sleeve 262. The bottom of the lifting pin 261 is fixedly connected to the first flange 263. The first flange 263 is driven to move up and down inside the sleeve 262 by a driving device. The driving device includes any one of a cylinder, a motor, and a hydraulic cylinder.

[0060] like Figure 3 As shown, a mounting plate 27 is provided below the base. To prevent leakage of reaction gas in the reaction chamber, several sealing rings 28 are provided between the mounting plate 27 and the inner wall of the reaction chamber. The second flange 265 is fixedly installed on the top end face of the sleeve, and both the second flange 265 and the top end of the sleeve are located inside the mounting plate 27. In this embodiment, an annular edge 2621 is provided on the outer periphery of the top end of the sleeve 262. The second flange 265, the edge 2621, and the mounting plate 27 are sequentially connected by bolts to achieve a fixed connection between the lifting pin assembly 26 and the mounting plate 27.

[0061] The bellows 264 corresponds to the channel position and is used to isolate the vacuum environment and atmospheric environment of the reaction chamber. Figure 4 In the diagram, point B represents the vacuum environment, and point C represents the atmospheric environment. The top and bottom ends of the bellows 264 are fixedly connected to the bottom surface of the second flange and the top surface of the first flange, respectively, and the bottom of the lifting pin 261 is located inside the bellows 264. The bellows 264 isolates the vacuum environment from the atmospheric environment, effectively preventing precipitates generated by friction from entering the reaction chamber.

[0062] In this embodiment, the bellows 264, the first flange 263, and the second flange 265 are made of stainless steel, and the sleeve 262 is made of copper.

[0063] The inner wall of the sleeve is provided with several mounting holes 267, each used to mount a corresponding first spring 266. In this embodiment, to ensure high conductivity and sufficient rigidity of the first spring 266, the material of the first spring 266 can be any of copper alloy or silver-copper alloy. The first spring 266 remains in a deformed state, with both ends of the first spring 266 positioned within the mounting holes 267 and abutting against the inner wall of the mounting holes. The arc-shaped surface in the middle of the first spring 266 protrudes from the mounting holes 267 and abuts against the outer wall of the first flange. The first spring 266 is elastically connected between the outer wall of the first flange and the inner wall of the sleeve, achieving equipotential between the first flange 263 and the sleeve 262. When the first flange 263 moves up and down, the first spring 266 slides to connect with the first flange 263. (See Figure 4.) Figure 4A As shown, to facilitate the installation of the first spring 266 and prevent it from detaching from the mounting hole 267, in this embodiment, the inner diameter d2 of the mounting hole 267 is larger than the opening diameter d1 of the mounting hole 267. In this embodiment, several first springs 266 are evenly distributed on both sides of the first flange.

[0064] like Figure 4A As shown, when the first flange 263 swings, the pressure on the first spring 266 on one side of the first flange increases (the distance between the two ends of the first spring 266 on that side increases), while the pressure on the first spring 266 on the other side of the first flange decreases (the distance between the two ends of the first spring 266 on that side decreases). However, the first springs 266 on both sides of the first flange always maintain their deformed state and abut against the outer wall of the first flange (the first spring 266 will not have a loose connection with the first flange 263). Therefore, regardless of how the first flange 263 swings, the first flange 263, the first spring 266, and the sleeve 262 always maintain a good electrical connection. Even if the inner wall of the mounting hole and the outer wall of the first flange 263 are worn, resulting in an increased tolerance gap between the first flange 263 and the sleeve 262, the first spring 266 can still abut against the outer wall of the first flange by changing its deformed state, and the sleeve 262, the first spring 266, and the first flange 263 always maintain a good electrical connection. This good electrical connection ensures that the sleeve 262 and the first flange 263 are at the same potential, preventing discharge arcing.

[0065] Example 2

[0066] like Figure 5As shown, in this embodiment, a ball bearing 360 disposed within a mounting hole replaces the first spring in Embodiment 1. The ball bearing 360 is positioned between the sleeve 362 and the first flange 363, with its diameter matching the inner diameter of the mounting hole. The ball bearing 360 extends from the mounting hole and abuts against the outer wall of the first flange. During the up-and-down movement of the first flange 363, the ball bearing 360 rolls and connects to the outer wall of the first flange. To ensure high conductivity and sufficient rigidity of the ball bearing 360, in this embodiment, the ball bearing 360 is made of stainless steel, and its outer surface is coated with a conductive coating, which includes either a graphene coating or an MXene coating. MXene coatings, i.e., graphene-like 2D conductive materials, have high hardness. In this embodiment, the ball bearing 360 achieves electrical connection between the sleeve 362 and the first flange 363, ensuring that the sleeve 362 and the first flange 363 are at the same potential, thus preventing discharge and arcing.

[0067] The ball bearing 360 rolls to connect the first flange 363, which not only reduces friction and facilitates the lifting of the ejector pin, but also reduces wear on the sleeve 362 and the first flange 363, effectively prevents metal deposits generated by friction, and greatly improves the service life of the ejector pin assembly 36.

[0068] Example 3

[0069] In Embodiment 2, due to long-term use, the rolling of the ball bearing 360 will wear down the mounting hole, causing the hole diameter to increase. This results in uncontrollable electrical contact between the ball bearing 360 and the outer wall of the first flange (the ball bearing 360 cannot be guaranteed to extend out of the mounting hole). At this time, due to the oscillation of the first flange 363, short-term contact will still occur between the first flange 363 and the sleeve 362, causing electrical discharge and sparking. To solve this problem, as shown in Figure 6... Figure 6A As shown, in this embodiment, an arc-shaped first spring 466 and a ball bearing 460 matching the mounting hole 467 are provided in the mounting hole 467 of the lifting pin assembly 46.

[0070] like Figure 6 , Figure 6AAs shown in Figure 6A, the first spring plate 466 is disposed within the mounting hole 467 and remains deformed, with the arc-shaped surface of the first spring plate 466 protruding from the first flange 463. The ball bearing 460 is disposed between the arc-shaped surface of the first spring plate 466 and the outer wall of the first flange. The deformation restoring force of the first spring plate 466 compresses the ball bearing 460, causing it to partially extend out of the mounting hole 467 and abut against the outer wall of the first flange. As shown in Figure 6A, to prevent the ball bearing 460 from detaching from the mounting hole 467, in this embodiment, the inner diameter of the mounting hole is larger than the opening diameter of the mounting hole. When the first flange 463 moves up and down, the ball bearing 460 rolls and connects to the first flange 463. By engaging the first spring 466 with the ball bearing 460, the sliding friction between the sleeve 462 and the first flange 463 is changed to the rolling friction between the ball bearing 460 and the first flange 463. Simultaneously, the surface contact between the sleeve 462 and the first flange 463 is changed to a point contact between the ball bearing 460 and the first flange 463. This not only facilitates the lifting and lowering of the ejector pin 461 and reduces wear on the sleeve 462 and the first flange 463, but also eliminates concerns about the first flange 463 becoming stuck due to an excessively tight fit. Therefore, in this embodiment, the tolerance gap between the first flange 463 and the sleeve 462 can be less than 0.015mm, further improving the concentricity of the sleeve 462 and the first flange 463 and preventing the first flange 463 from getting stuck.

[0071] Even if long-term use causes wear on the mounting hole 467 caused by the ball bearing 460, the deformation restoring force of the first spring 466 can still ensure that the ball bearing 460 abuts against the outer wall of the first flange. The ball bearing 460 and the first flange 463 will not have a loose connection. While reducing friction, the first spring 466 and the ball bearing ensure good electrical contact between the sleeve 462 and the first flange 463, preventing electrical discharge and sparking.

[0072] Example 4

[0073] like Figure 7 , Figure 7A As shown, to further ensure the stability of the rolling connection between the ball bearing 560 and the first flange 563, in this embodiment, in addition to the first spring 566 and the ball bearing 560, a second spring 568 and a third spring 569 are also provided in the mounting hole 567 of the lifting pin assembly 56. The arc-shaped surface of the second spring 568 protrudes downward, and the arc-shaped surface of the third spring 569 protrudes upward. The ball bearing is disposed between the second spring 568 and the third spring 569 and abuts against the arc-shaped surfaces of the second spring 568 and the third spring 569.

[0074] To ensure high conductivity and sufficient rigidity of the second reed 568 and the third reed 569, the materials of the second reed 568 and the third reed 569 can be either copper alloy or silver-copper alloy.

[0075] like Figure 3 As shown, the present invention also provides a plasma reaction device 2, which includes a vacuum reaction chamber 20, a base 231 inside the vacuum reaction chamber, and an electrostatic chuck 2311 for placing a wafer W above the base 231. Both the base 231 and the electrostatic chuck 2311 are provided with a plurality of through holes, and each through hole on the base 231 and the corresponding through hole on the electrostatic chuck 2311 form a vertical channel. The plasma reaction device 2 includes:

[0076] At least three lifting pin assemblies 26 as described in this invention.

[0077] In an embodiment of the present invention, the first flange of each lifting pin assembly is synchronously driven by a driving device, so that the lifting pins of each lifting pin assembly are always kept on the same plane, stably supporting the wafer W.

[0078] The lifting pin assembly of this invention incorporates several conductive elastic devices between the sleeve and the first flange. These elastic devices maintain constant electrical contact with both the sleeve and the first flange, ensuring that the sleeve and the first flange remain at the same potential. This prevents potential differences between the sleeve and the first flange in a radio frequency field environment, which could lead to arcing or welding failure. This effectively reduces contaminant generation, ensures the stability of the electrostatic chuck operation, and improves the service life of the lifting pin assembly. The elastic device can be a single spring or a combination of at least one spring and a ball bearing.

[0079] This invention utilizes a spring and ball bearing to ensure stable rolling connection between the ball bearing and the first flange, guaranteeing good electrical contact between the sleeve and the first flange. This ensures that the sleeve and the first flange maintain equal potential in a radio frequency (RF) field, effectively preventing arcing between them. Furthermore, the rolling ball bearing connection transforms the surface contact between the first flange and the sleeve into a point contact between the first flange and the ball bearing. The sliding friction between the first flange and the sleeve is replaced by rolling friction between the first flange and the ball bearing. This effectively prevents misalignment caused by wear between the sleeve and the first flange, which could lead to jamming of the lifting pin during lifting. It also reduces metal deposits caused by friction, ensuring the yield of wafer W and further improving the lifespan of the lifting pin assembly.

[0080] By using a spring and a ball joint, this invention can further reduce the clearance of the tolerance fit between the sleeve and the first flange, improve the concentricity of the first flange and the sleeve during the up and down movement, and prevent the lifting pin from getting stuck during the lifting process.

[0081] This invention effectively isolates the vacuum environment and atmospheric environment within the reaction chamber through a corrugated pipe, preventing contaminants generated by electrical discharge and sparking, as well as metal precipitates generated by friction, from entering the reaction chamber, thus ensuring the yield of wafer W.

[0082] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A lifting pin assembly for use in a vacuum reaction chamber, the vacuum reaction chamber including a base, an electrostatic chuck for placing a wafer being disposed above the base, both the base and the electrostatic chuck having a plurality of through holes, each through hole on the base and the corresponding through hole on the electrostatic chuck forming a vertical channel, characterized in that, The lifting pin assembly includes: Lifting pins are used to lift the wafer through the corresponding channels to separate the wafer from the surface of the electrostatic chuck. The sleeve is fixedly connected below the base and corresponds to the channel position where the lifting pin is located. The first flange is disposed inside the sleeve and is clearance-fitted with the sleeve. The bottom of the lifting pin is fixedly connected to the first flange. The first flange is driven to move up and down inside the sleeve by a driving device. Several conductive elastic devices are distributed on both sides of the first flange; the elastic devices are elastically connected between the outer wall of the first flange and the inner wall of the sleeve to achieve equipotential between the first flange and the sleeve; when the first flange moves up and down, the elastic devices are slidably or rollingly connected to the first flange.

2. The lifting pin assembly as described in claim 1, characterized in that, The elastic device has an arcuate surface that protrudes toward the first flange and abuts against the outer wall of the first flange.

3. The lifting pin assembly as described in claim 1, characterized in that, The inner wall of the sleeve is provided with several mounting holes, each used to install a corresponding elastic device.

4. The lifting pin assembly as described in claim 3, characterized in that, The elastic device is an arc-shaped first spring; both ends of the first spring are disposed in the mounting hole and abut against the inner wall of the mounting hole; the arc-shaped surface in the middle of the first spring protrudes from the mounting hole and abuts against the outer wall of the first flange; when the first flange moves up and down, the first spring slides and connects to the first flange.

5. The lifting pin assembly as described in claim 3, characterized in that, The elastic device includes: an arc-shaped first spring and a ball bearing that matches the mounting hole; The first spring is disposed in the mounting hole and remains in a deformed state; the arc-shaped surface of the first spring protrudes from the first flange; The ball bearing is disposed in the mounting hole and located between the arc-shaped surface of the first spring and the outer wall of the first flange; the ball bearing is squeezed by the deformation restoring force of the first spring, so that the ball bearing extends out of the mounting hole and abuts against the outer wall of the first flange; when the first flange moves up and down, the ball bearing rolls and connects to the first flange.

6. The lifting pin assembly as described in claim 5, characterized in that, The elastic device further includes an arc-shaped second spring and a third spring; the second and third springs are disposed in the mounting hole, with the arc-shaped surface of the second spring convex downward and the arc-shaped surface of the third spring convex upward, and a ball is disposed between the second and third springs and abuts against the arc-shaped surfaces of the second and third springs.

7. The lifting pin assembly as described in claim 1, characterized in that, A second flange is also fixedly provided on the top end face of the sleeve; a mounting plate is provided below the base, and the top end of the sleeve and the second flange are both located inside the mounting plate.

8. The lifting pin assembly as described in claim 7, characterized in that, It also includes a bellows corresponding to the channel position; the top and bottom ends of the bellows are fixedly connected to the bottom surface of the second flange and the top surface of the first flange, respectively; the bottom of the lifting pin is located inside the bellows.

9. The lifting pin assembly as described in claim 1, characterized in that, The plurality of conductive elastic devices are uniformly or non-uniformly distributed on both sides of the first flange.

10. The lifting pin assembly as described in claim 6, characterized in that, The first to third elastic springs are made of either copper alloy or silver-copper alloy.

11. The lifting pin assembly as described in claim 8, characterized in that, The bellows, first flange, and second flange are made of stainless steel, while the sleeve is made of copper.

12. The lifting pin assembly as described in claim 5, characterized in that, The ball bearings are made of stainless steel and have a conductive coating on their outer surface.

13. The lifting pin assembly as described in claim 12, characterized in that, The conductive coating includes either a graphene coating or an MXene coating.

14. The lifting pin assembly as described in claim 1, characterized in that, The top of the lifting pin is provided with a disc-shaped structure, the diameter of which is larger than the diameter of the lifting pin but smaller than the diameter of the through hole.

15. The lifting pin assembly as described in claim 1, characterized in that, The drive device includes any one of a cylinder, a motor, or a hydraulic cylinder.

16. A plasma reaction apparatus, comprising a vacuum reaction chamber, the vacuum reaction chamber containing a base, an electrostatic chuck for placing a wafer being disposed above the base, both the base and the electrostatic chuck having a plurality of through holes, each through hole on the base forming a vertical channel with a corresponding through hole on the electrostatic chuck, characterized in that, The plasma reaction device includes: Multiple lifting pin assemblies as described in any one of claims 1 to 15.

Images