Particle deposition prevention shielding piece for coating equipment

Abstract

The invention discloses a particle deposition prevention shielding piece for coating equipment, which is arranged in a coating cavity and comprises an annular upper plate and an annular lower plate, and a labyrinth type airflow channel is formed between the upper plate and the lower plate through baffles which are staggered up and down and arranged at intervals; a gap of 0-2mm exists between the outer edge of the shielding piece and the inner wall of the film coating cavity, the cavity wall of the film coating cavity is grounded, and the gap is constructed into an electron depletion region mainly comprising positive charges; according to the utility model, particles entering by mistake are intercepted through the labyrinth type channel, particles escaping along the gap are blocked through the electron depletion region, the pollution frequency of the lower cavity can be greatly reduced, and thus the downtime and the maintenance cost of equipment are reduced; the labyrinth type airflow channel and the electron depletion area are both designed in a non-blocking mode, the labyrinth type airflow channel does not hinder normal conveying of reaction gas, the electron depletion area does not affect lifting of the wafer and the shielding piece, the anti-pollution function is achieved, meanwhile, the technological rhythm of existing coating equipment is completely adapted, and the main body structure of the equipment does not need to be changed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wafer coating equipment, and particularly relates to a particle deposition prevention shield for a coating equipment. BACKGROUND

[0002] In a plasma coating process, the shield is a key component for separating the reaction area from the lower cavity, and its core function is to block the particles (including plasma charged ions, metal particles, etc.) generated in the reaction process to avoid them from falling down and polluting the stage and the lower cavity components.

[0003] The shield used in the existing coating equipment is mostly a simple annular thin plate structure, which is only used for shielding the wafer edge. In order to place the shield, a hook-shaped structure is arranged on the inner wall of the reaction cavity, the inner wall of the hook-shaped structure is used for supporting the shield, and the groove bottom of the hook-shaped structure is provided with a gas inlet hole, and the reaction gas enters and exits the reaction area through the gas inlet hole. When working, the shield is lifted by the stage and the wafer, and is away from the hook-shaped structure, and the deposited particles can escape to the lower cavity through the gap between the two, resulting in a high pollution frequency of the lower cavity components, which needs to be frequently disassembled and cleaned, greatly increasing the maintenance cost and process interruption time of the equipment. SUMMARY

[0004] The present application aims at overcoming the deficiencies in the prior art, and provides a particle deposition prevention shield for a coating equipment.

[0005] The present application provides a particle deposition prevention shield for a coating equipment, which is arranged in a coating cavity and comprises an upper plate and a lower plate arranged in a ring shape, the upper plate is connected with the lower plate, and a closed space is formed between the upper plate and the lower plate; a baffle is arranged in the closed space and is staggered and arranged in an interval, the baffle can complicate the flow path of the gas in the closed space, and the closed space is constructed into a labyrinth type gas flow channel; there is a gap of 0-2mm between the outer edge of the shield and the inner wall of the coating cavity, the cavity wall of the coating cavity is grounded, and the gap is constructed into an electron depletion region mainly with positive charges; a gas inlet hole is arranged on the lower plate, and a gas outlet hole is arranged on the upper plate; when the coating equipment works, the stage carries the wafer to rise and lift the shield, the reaction gas enters the labyrinth type gas flow channel through the gas inlet hole, and then flows out of the gas outlet hole and enters the reaction area; the particles entering the labyrinth type gas flow channel through the gas outlet hole will finally be deposited in the labyrinth type gas flow channel due to the impact of the baffle caused by the tortuous channel; the particles entering the electron depletion region will be limited due to the strong electric field force and the charge separation characteristics, and finally lose activity or cannot break through the gap; the labyrinth type gas flow channel and the electron depletion region cooperate to limit the movement range of the particles and avoid their pollution to the stage or the lower cavity, thereby ensuring the stability of the coating process and the preparation yield of the film.

[0006] Further, the inner wall of the coating cavity is provided with a wall-hanging extending to the cavity center, the wall-hanging is used for supporting the shielding member; a plurality of elastic conductive members are arranged on the wall-hanging and are distributed equidistantly along the circumferential direction, when the shielding member is arranged on the wall-hanging, the elastic conductive members are compressed, electrically connected with the shielding member and the cavity wall of the coating cavity, so that the shielding member and the cavity wall are electrically connected in potential.

[0007] Further, the outer edge of the lower surface of the lower plate is provided with a groove, when the shielding member is arranged on the wall-hanging, the wall-hanging is inserted into the groove; in the labyrinth air flow channel, a step structure is arranged at the inner side region corresponding to the groove, the step structure extends in a ladder shape and forms at least one convex step to increase the tortuosity of the labyrinth air flow channel; the horizontal step surface of the step is opposite to the air outlet hole, and the distance between the horizontal step surface and the air outlet hole is smaller than the channel width of the main body section of the labyrinth air flow channel, so as to reduce the activity space of the mistaken particles and accelerate the kinetic energy consumption of the mistaken particles.

[0008] Further, the shielding member is made of titanium or titanium alloy; or the shielding member is made of aluminum alloy, and an electrically conductive coating is arranged at the indirect grounding connection position of the shielding member.

[0009] Further, the upper plate and the lower plate are detachably connected; the edge positions of the upper plate and the lower plate are provided with a corresponding positioning hole and a positioning pin; the upper surface of the lower plate is provided with an embedding groove, and the inner edge of the upper plate can be inserted into the embedding groove; a sealing ring is arranged between the upper plate and the lower plate to prevent the gas or particles from escaping from the connection position of the two plates; and an electrically conductive ring is further arranged between the upper plate and the lower plate to realize the electrical connection of the upper plate and the lower plate.

[0010] Further, the electrically conductive ring is an elastic metal spring made of beryllium copper alloy or silver-plated copper alloy; the cross-sectional shape of the electrically conductive ring is C-shaped, U-shaped or Ω-shaped; the lower surface of the upper plate and / or the upper surface of the lower plate is provided with an annular groove for accommodating the electrically conductive ring, and the electrically conductive ring is fixed in the annular groove by interference fit and is pressed between the upper plate and the lower plate; the electrically conductive ring can provide a continuous contact pressure by elastic deformation, so as to resist the surface oxidation, microscopic unevenness and thermal deformation of the plate, thereby maintaining the electrical connection between the upper plate and the lower plate.

[0011] Further, the baffle includes an upper baffle arranged on the lower surface of the upper plate and a lower baffle arranged on the upper surface of the lower plate, and the upper baffle and the lower baffle are both annular structures coaxial with the shielding member; the upper baffle and the lower baffle are staggered and distributed along the radial direction of the shielding member; the number of baffles is at least 3; the distance between any two adjacent baffles is 2-8 mm; in the closed space, the vertical distance between the upper baffle and the upper surface of the lower plate is H1, and the vertical distance between the lower baffle and the lower surface of the upper plate is H2, and the value range of H1 and H2 is both 0.5-2 mm, and H1 < H2.

[0012] Further, the inner wall of the labyrinth air flow channel is coated with a polytetrafluoroethylene anti-sticking coating, which can change the adhesion state of particles in the labyrinth air flow channel, and change the solid scale into loose accumulation; and / or, the bottom of the labyrinth air flow channel is provided with an arc-shaped groove, which is located on the downstream side of the baffle or the outer side of the air flow turning position, which can maximize the settling efficiency by using the low-speed area, and guide and concentrate the particles in the specified area.

[0013] Further, the inner edge of the shield is arranged in a stepped manner, including a first inclined surface formed by the inner edge of the upper plate, a second inclined surface formed by the inner edge of the lower plate, and a horizontal connecting surface formed by the upper surface of the lower plate between the first inclined surface and the second inclined surface; the second inclined surface can capture particles that are obliquely incident at a large angle and would otherwise be deposited in the edge region of the wafer; the first inclined surface and the horizontal connecting surface can tighten the opening exposed to the target material, and ensure that the central region of the wafer that needs to be coated is exposed to the particle flow; the end of the wafer abutting against the inner edge of the shield is provided with a circular arc chamfer with a radius of 0.5-1.5mm, which is used to reduce the contact area between the lower plate and the wafer, and avoid adhesion between the two.

[0014] Further, a plurality of gas outlet holes are arranged on the upper plate and are equally spaced in the circumferential direction, a plurality of gas inlet holes are arranged on the lower plate and are also equally spaced in the circumferential direction, the number of gas inlet holes is greater than the number of gas outlet holes, and the total flow area of the gas inlet holes is greater than the total flow area of the gas outlet holes, so as to establish a uniform and stable back pressure in the labyrinth air flow channel, ensure the uniformity of the reaction gas flow, and avoid disturbance of the plasma stability in the reaction region by high-speed airflow; and / or, the gas inlet holes are arranged in a trumpet shape, the hole diameter of the gas inlet holes becomes larger as they are farther away from the upper plate, and the expansion angle of the gas inlet holes is 45°-60°, so as to guide the reaction gas to uniformly enter the labyrinth air flow channel.

[0015] The present application also provides a particle deposition prevention shield for a coating equipment, which is arranged in a coating chamber and includes an upper plate and a lower plate arranged in a ring shape, and a labyrinth air flow channel formed between the upper plate and the lower plate by baffles arranged in an upper-lower staggered and spaced manner; a gap of 0-2mm exists between the outer edge of the shield and the inner wall of the coating chamber, the chamber wall of the coating chamber is grounded, and the gap is configured as an electron depletion region mainly with positive charges; the particles that mistakenly enter are intercepted through the labyrinth channel, and the particles that escape along the gap are blocked by the electron depletion region, which can greatly reduce the pollution frequency of the lower cavity, thereby reducing the downtime and maintenance cost of the equipment; the labyrinth air flow channel and the electron depletion region are both non-blocking designs, the labyrinth channel does not hinder the normal delivery of the reaction gas, and the electron depletion region also does not affect the lifting of the wafer and the shield, which fully adapts to the process rhythm of the existing coating equipment without the need to modify the main structure of the equipment. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 A schematic diagram of the structure of a particle deposition shielding element for coating equipment provided in this application within the coating cavity; Figure 2 for Figure 1 The diagram shows a cross-sectional view of the anti-particle deposition mask used in a coating equipment within the coating chamber. Figure 3 for Figure 1 The diagram shows a cross-sectional view of the anti-particle deposition mask used in coating equipment. Figure 4 for Figure 3 The diagram shows a partial structural schematic of a particle deposition shielding component used in coating equipment. Figure 5 for Figure 3 The diagram shown is an exploded view of the structure of a particle deposition shielding component used in coating equipment. Detailed Implementation

[0017] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0018] This application provides a particle deposition shielding device for a coating equipment, disposed within a coating cavity 10. It includes an annular upper plate 1 and a lower plate 2, connected to form a closed space between them. The closed space contains staggered and spaced baffles 3, which complicate the gas flow path within the closed space, creating a labyrinthine airflow channel. A 0-2mm gap exists between the outer edge of the shielding device and the inner wall of the coating cavity 10. The cavity wall of the coating cavity 10 is grounded, creating an electron depletion region dominated by positive charges. The lower plate 2 has an air inlet 2a, and the upper plate 1 has an air outlet 1a. During operation of the coating equipment… The stage 20 carries the wafer upward and lifts the shield. The reaction gas enters the labyrinth-shaped airflow channel through the inlet 2a, then flows out through the outlet 1a and enters the reaction area. Particles entering the labyrinth-shaped airflow channel through the outlet 1a will collide with the baffle 3 due to the tortuous channel and eventually deplete their kinetic energy and settle in the labyrinth-shaped airflow channel. Particles entering the electron depletion region will eventually lose their activity or be unable to break through the gap due to the strong electric field force and the separation characteristics of the charge. The labyrinth-shaped airflow channel and the electron depletion region work together to limit the movement range of the particles and prevent them from contaminating the stage 20 or the cavity below, thereby ensuring the stability of the coating process and the yield of the thin film.

[0019] For details, please refer toFigure 1 and Figure 2 In the illustrated embodiment, the coating cavity 10 is a closed vacuum cavity, which is the core space of film deposition. The coating cavity 10 is divided into an upper cavity and a lower cavity (part of the coating cavity 10 is shown, not the complete cavity), the upper cavity is provided with a target material at the top, and the lower cavity is provided with a carrier 20 at the bottom; the shielding member is located between the target material and the carrier 20, and is generally suspended in the coating cavity 10 through a platform or sliding mechanism (such as a sliding rail, a sliding groove, etc.). The cavity wall of the coating cavity 10 is grounded to provide a stable zero potential reference and form an electric field loop required for plasma, thereby ensuring effective transmission of radio frequency energy and integrity of the current loop.

[0020] The carrier 20 is located below the shielding member and is a wafer carrying and lifting component, which can drive the wafer to move in the vertical direction. During operation, the carrier 20 carries the wafer to rise and lift the shielding member, so that the wafer enters the reaction area below the target material.

[0021] The target material is located above the shielding member and is a "particle source" (such as a vanadium target for vanadium oxide coating) for film deposition, which generates metal atoms to be deposited through plasma sputtering after being powered on.

[0022] In combination with reference to Figures 3 to 5 The shielding member is a ring structure and is located between the target material and the carrier 20, which is a key component for separating the reaction area and the lower cavity, and can prevent the deposited particles from continuing to escape downward.

[0023] In combination with reference to Figures 1 to 4 The shielding member is composed of an upper plate 1 and a lower plate 2 connected together, and there is a closed space between the upper plate 1 and the lower plate 2 for gas circulation. The closed space is provided with an upper baffle (fixed to the lower surface of the upper plate 1 and spaced from the upper surface of the lower plate 2) and a lower baffle (fixed to the upper surface of the lower plate 2 and spaced from the lower surface of the upper plate 1), both of which are ring structures coaxial with the shielding member and are arranged in a staggered and spaced manner along the radial direction of the shielding member, thereby constructing the closed space into a labyrinth-type channel with multiple bends.

[0024] In combination with reference to Figure 4 The lower plate 2 is provided with an air inlet hole 2a, and the upper plate 1 is provided with an air outlet hole 1a. The coating cavity 10 is provided with an air inlet, and the air inlet is connected to a reaction gas supply device outside; the air inlet is located below the shielding member. During the coating process, the reaction gas enters the lower cavity through the air inlet, then enters the labyrinth-type airflow channel inside the shielding member through the air inlet hole 2a, the gas entering the closed space cannot flow in a straight line and needs to flow along a tortuous path of "upward-rightward-downward-rightward-upward", and finally enters the reaction area through the air outlet hole 1a to participate in the ionization reaction.

[0025] When the particles (such as metal atoms, plasma) in the reaction region are deposited downward and pass through the outlet hole 1a into the labyrinth gas flow channel in the reverse direction, the tortuous path forces the particles to hit the baffle 3 multiple times, and each impact consumes the kinetic energy of the particles. After 2 to 4 impacts, the kinetic energy of the particles is completely consumed, and under the action of gravity, the particles fall to the bottom of the channel and cannot continue to move towards the inlet hole 2a, so they cannot enter the lower cavity.

[0026] In addition, the tortuous structure of the labyrinth gas flow channel can also slow down the gas flow speed and avoid the disturbance of high-speed gas flow to the plasma in the reaction region, thereby ensuring uniform gas distribution on the wafer surface and helping to improve the uniformity of the coating.

[0027] Continuing to refer to Figure 1 and Figure 2 The inner wall of the coating cavity 10 is provided with a hanging wall 11 extending to the center of the cavity, and the shielding member is arranged on the hanging wall 11 and supported by the hanging wall 11 and suspended above the carrier 20. An annular gap of 0-2mm is reserved between the outer edge of the shielding member and the inner wall of the coating cavity 10. The width of the gap is much smaller than the prior art (conventional >5mm), and the width of the gap is uniform along the circumferential direction (error ≤±0.1mm), which provides space for charge concentration.

[0028] Since the cavity wall of the coating cavity 10 is connected to the ground through a grounding terminal (usually arranged on the outer wall of the cavity), the potential of the cavity wall is 0; at the same time, the shielding member is indirectly grounded through the hanging wall 11 or the carrier 20, and the potential of the shielding member also tends to be 0.

[0029] After the gap is formed, the free electrons near the gap in the reaction region will move to the grounded shielding member or cavity wall due to their extremely small mass and fast speed, and will be quickly guided away through the grounding circuit; while the positive ions (such as argon ions, metal ions) cannot migrate synchronously due to their large mass and slow speed, and will be left in the gap, eventually forming an electron depletion region dominated by positive charges and lacking in electrons.

[0030] The role of the electron depletion region is to prevent particles from entering the lower cavity through the gap between the outer edge of the shielding member and the cavity wall. Specifically, for charged particles (electrons, positive ions), the electrons in them will be quickly guided away by the grounded surface and cannot accumulate in the gap; while the positive ions will be repelled by the "positive charge area" in the gap (the direction of the electric field force is opposite to the direction of the positive ion motion), and their kinetic energy will gradually decay, eventually being "pushed back" to the reaction region and unable to break through the gap. For neutral particles (such as un-ionized metal atoms), although they are not affected by the electric field force, the narrow gap of 0-2mm itself will increase the diffusion resistance of the neutral particles, and the labyrinth gas flow channel has already intercepted most of the neutral particles through sedimentation, so it is difficult for the remaining few neutral particles to pass through the gap and enter the lower cavity.

[0031] The electron depletion region is like an invisible wall that can completely cut off the path of particle leakage along the gap.

[0032] The labyrinth air flow channel and the electron depletion zone are set in cooperation. On the one hand, the particles that enter by mistake are intercepted by the labyrinth channel, and the particles that escape along the gap are blocked by the electron depletion zone, so that the double protection can greatly reduce the pollution frequency of the lower cavity, thereby reducing the downtime and maintenance cost of the equipment. On the other hand, the labyrinth channel can guide the uniform flow of the reaction gas, avoid the air flow disturbing the plasma, help to ensure the stability of the film coating process, and effectively improve the composition uniformity and yield of the film.

[0033] In addition, the labyrinth air flow channel and the electron depletion zone are both non-blocking designs. The labyrinth channel will not hinder the normal delivery of the reaction gas, and the electron depletion zone will not affect the lifting of the wafer and the shield, so that the anti-pollution function is realized while fully adapting to the process rhythm of the existing film coating equipment without changing the main structure of the equipment.

[0034] The anti-particle deposition shield for the film coating equipment provided in the present application is composed of a closed space between the annular upper plate 1 and the lower plate 2, and the upper and lower staggered baffles 3 inside the closed space, which forms a labyrinth air flow channel. The particles that enter by mistake through the gas outlet hole 1a are settled due to the tortuous channel, impact on the baffles 3, and depletion of kinetic energy, thereby preventing the particles from diffusing downward. Further, through the 0-2mm gap between the outer edge of the shield and the inner wall of the film coating cavity 10, combined with the electron depletion zone formed by the grounding of the cavity wall, the particles are restricted from breaking through the gap by means of strong electric field force and charge separation characteristics, thereby cutting off the path of the particles leaking along the gap. The two cooperate to limit the particles and prevent them from polluting the non-film coating area downward, thereby reducing the frequency of cleaning and maintenance of the equipment, reducing the maintenance cost and process interruption risk, and ensuring the uniform flow of the reaction gas, thereby ensuring the stability of the film coating process and the yield of the film.

[0035] In an embodiment, the inner wall of the film coating cavity 10 is provided with a hanging wall 11 extending to the center of the cavity. The hanging wall 11 is used to support the shield.

[0036] For details, please refer to Figure 1 and Figure 2 In the illustrated embodiment, the hanging wall 11 is an annular support platform protruding towards the center of the cavity around the inner side of the cavity wall, which is adapted to the annular shape of the shield and can provide a uniform support contact surface for the shield. When the carrier 20 is not carrying the wafer, the shield can be stably placed on this circle of hanging walls 11, thereby maintaining the state of being suspended at a specific position above the carrier 20. In this way, the structural and positional stability of the shield in the non-working state can be ensured, and the structural preparation for the subsequent lifting of the shield by the carrier 20 carrying the wafer to enter the working state is made, thereby ensuring the positional accuracy of the shield when switching between the working and non-working states.

[0037] Optionally, the hanging wall 11 is provided with a plurality of elastic conductive members, which are distributed equidistantly along the circumferential direction. When the cover is placed on the hanging wall, the elastic conductive members are compressed to electrically connect the cover and the cavity wall of the coating cavity 10, so that the cover and the cavity wall are electrically connected.

[0038] It should be explained that the electron depletion region still needs to be maintained after the coating is completed, because there are still particles that have not completely settled in the reaction area during the process of once coating, the carrier 20 descending, and the wafer transferring. If the cover cannot be immediately connected to the cavity wall of the coating cavity 10 to form an electrical equipotential connection and make the electron depletion region invalid after the cover leaves the wafer and the carrier 20, the residual particles are likely to leak into the lower cavity through the gap between the cover and the cavity wall.

[0039] The elastic conductive members (such as springs or elastic sheets made of conductive materials) are added to utilize the elastic deformation characteristics of the elastic conductive members to realize the electrical potential conduction in advance before the cover is completely lowered back to the hanging wall 11 with the carrier 20 descending, so as to ensure that the equipotential connection between the cover and the grounded cavity wall is not interrupted at all times (only when the cover and the cavity wall are kept at the same potential, can the electrons in the gap be quickly conducted away, and the positive ions can be effectively retained, thereby forming a stable strong electric field to constrain the particles and block the particles from leaking into the lower cavity through the gap), and thus the stable function of the electron depletion region is maintained throughout the process.

[0040] Specifically, during the coating process, the cover is lifted by the wafer and the carrier 20, the physical contact with the hanging wall 11 is broken, and the electrical connection is cut off. However, the lower plate 2 of the cover directly contacts the edge of the wafer or the carrier 20. Since the carrier 20 is grounded and the wafer is firmly adsorbed by the grounded carrier 20 (usually an electrostatic chuck), the cover can maintain a potential close to the ground potential through the direct path of “cover-carrier” or the indirect path of “cover-wafer-carrier”. This grounding path is sufficient to maintain the electric field in the narrow gap region and ensure the existence of the electron depletion region.

[0041] After the coating is completed, the carrier 20 is lowered, the cover falls without support, first contacts the elastic conductive members (at this time, the elastic conductive members are in an extended state and are located higher because they are not under pressure, and can even not be separated from the cover), and continuously compresses them, and finally falls back to the hanging wall 11. Since the elastic conductive members are connected to the cavity wall of the coating cavity 10 and are in a grounded state, the cover can establish a permanent path with low resistance and high reliability during the falling process, and realize equipotential connection with the grounded cavity wall in advance, thereby ensuring the continuity of the electron depletion region.

[0042] Optionally, the elastic conductive members are spring sheets (crescent-shaped) or finger springs made of beryllium copper. Beryllium copper has excellent electrical conductivity and elasticity, and can better meet the grounding requirements.

[0043] Optionally, the elastic conductive members are stainless steel spring sheets.

[0044] Optionally, the hanging wall 11 is provided with a plurality of elastic conductive members, which are distributed equidistantly along the circumferential direction, and any elastic conductive member is connected to the cavity wall of the film-coated cavity 10 through the metal woven belt. When the shade falls back to the hanging wall 11, the outer edge or back surface of the shade will be pressed on the elastic conductive member, and a plurality of uniform and reliable electrical connection points are formed by the weight of the shade and the elastic force of the elastic conductive member.

[0045] By using the elastic conductive member, on the one hand, the electrical connection can be realized in advance when the shade falls back, and on the other hand, the elastic design can compensate for thermal expansion and contraction and processing tolerance during equipment operation, so as to ensure the stable contact pressure of the shade and the cavity wall, thereby maintaining reliable electrical connection.

[0046] Optionally, the outer edge of the lower surface of the lower plate 2 is provided with a groove 2b, and when the shade is placed on the hanging wall 11, the hanging wall 11 is inserted into the groove 2b.

[0047] For details, please refer to Figures 1 to 4 In the illustrated embodiment, the groove 2b is provided on the outer edge of the lower surface of the lower plate 2, which is an annular structure extending along the circumferential direction of the lower plate 2, and the shape and size of the groove body are matched with the hanging wall 11, so that the hanging wall 11 can be accommodated.

[0048] When the shade is placed on the hanging wall 11, the hanging wall 11 is inserted into the groove 2b, and the cooperation of the two can position and fix the hanging position of the shade, which helps to ensure that the shade returns to the preset position above the carrier table 20 after lifting, so as to lay a foundation for the subsequent lifting of the carrier table 20 carrying the wafer, the accurate fitting of the shade with the wafer edge, the stability of the air flow path of the labyrinth air flow channel, and the uniformity of the gap between the outer edge of the shade and the cavity wall.

[0049] Optionally, a step structure 2c is provided in the labyrinth air flow channel corresponding to the inner side region of the groove 2b, and the step structure 2c extends in a stepped manner to form at least one raised step, so as to increase the tortuosity of the labyrinth air flow channel.

[0050] For details, please refer to Figure 3 and Figure 4 In the illustrated embodiment, the step structure 2c is arranged inside the labyrinth air flow channel and corresponds to the groove 2b (the position of the inwardly recessed groove 2b is protruded inside the labyrinth air flow channel to form a step structure 2c), and the whole is in a stepped shape extending along the circumferential direction of the shade. The profile of the step is matched with the inner wall of the labyrinth air flow channel, which can be naturally integrated into the overall structure of the channel, without hindering the basic flow of the reaction gas in the channel, and the stepped protruding form can change the path direction of the local channel.

[0051] The stepped structure 2c can increase the tortuosity of the labyrinth air flow channel. The stepped structure extends in a stepped manner and has a design with protruding steps. Based on the original tortuous path of the channel, the stepped structure further changes the trajectories of the air flow and the particles that have entered by mistake. The air flow needs to bypass the protruding steps to continue flowing to the air outlet hole 1a. The particles that have entered the closed space by mistake also need to collide with the steps and the baffles 3 more times, providing more opportunities for the consumption of the kinetic energy of the particles.

[0052] Optionally, the horizontal step surface of the step is directly opposite the air outlet hole 1a, and the distance between the horizontal step surface and the air outlet hole 1a is less than the channel width of the main body section of the labyrinth air flow channel, so as to reduce the activity space of the particles that have entered by mistake and accelerate the consumption of the kinetic energy of the particles.

[0053] For details, please refer to Figure 4 In the illustrated embodiment, the horizontal step surface of the step corresponding to the groove 2b is directly opposite the air outlet hole 1a, which serves to accurately intercept the particles that have entered the labyrinth air flow channel from the air outlet hole 1a. Specifically, if the particles in the reaction region enter the air outlet hole 1a, they can contact the step surface without going through complex diffusion, thereby causing most of the particles to quickly dissipate kinetic energy and creating a prerequisite for the subsequent consumption of kinetic energy and sedimentation of the particles.

[0054] It should be explained that the “main body section of the labyrinth air flow channel” refers to the basic tortuous channel section in the closed space formed by the upper and lower staggered baffles 3 that is not disturbed by the stepped structure 2c. The width of this section of the channel remains relatively uniform and is the main path for the flow of the reaction gas in the channel. For details, please refer to Figure 4 The relatively regular part of the channel profile between the baffles 3.

[0055] Making the distance between the horizontal step surface and the air outlet hole 1a less than the channel width of the main body section of the labyrinth air flow channel can further reduce the activity space of the particles that have entered by mistake. As can be easily understood, compared to the wider channel of the main body section, a narrower distance will cause the particles that have entered from the air outlet hole 1a to be blocked by the horizontal step surface in a very short distance. The movement path of the particles is compressed, the frequency of collision with the step surface or the baffles 3 increases, and the kinetic energy can be dissipated more quickly.

[0056] In an embodiment, the distance between the horizontal step surface and the air outlet hole 1a is strictly controlled within the range of 0.5-2 mm.

[0057] This distance design can greatly reduce the activity space of the particles that have entered the labyrinth air flow channel from the air outlet hole 1a. After entering from the air outlet hole 1a, the particles only need to move a short distance to contact the horizontal step surface and cannot diffuse in a large range in the channel, thereby further accelerating the dissipation of the kinetic energy of the particles.

[0058] At the same time, the spacing of 0.5-2mm neither hinders the normal diffusion of the reaction gas due to being too small, nor allows the particles to have enough space to change direction and avoid the step surface due to being too large, while ensuring the uniform flow of the reaction gas, and promoting the particle deposition.

[0059] Optionally, the shielding member is made of titanium or titanium alloy.

[0060] Titanium has excellent high-temperature resistance, can maintain its structural stability during the process of the coating film equipment (often accompanied by a high-temperature plasma environment), and is not prone to deformation due to high temperature, which helps to ensure that the gap between the shielding member and the coating cavity wall, as well as the size of the labyrinth air flow channel, always meet the design requirements, avoiding the influence of structural deformation on the particle prevention effect. At the same time, titanium has good electrical conductivity, which can ensure stable electrical connection between the shielding member and the cavity wall and the carrier 20, helping to form a uniform and effective electron depletion region. In addition, titanium also has excellent corrosion resistance, which can resist the erosion of reaction gas during the coating process, reduce material loss, and prolong the service life of the shielding member.

[0061] Titanium alloy further improves the mechanical strength and structural rigidity of the material on the basis of inheriting the core advantages of titanium such as high-temperature resistance, electrical conductivity, and corrosion resistance, making it more difficult for the shielding member to bend and deform during long-term use, and ensuring that the tortuosity of the labyrinth air flow channel and the uniformity of the gap are not destroyed. At the same time, the comprehensive performance of titanium alloy also makes the shielding member more durable when dealing with frequent process cycles, which can further reduce the replacement frequency of the shielding member.

[0062] Optionally, the shielding member is made of aluminum alloy, and the indirect grounding connection part of the shielding member is provided with a conductive coating.

[0063] The density of aluminum alloy is about 2.7g / cm 3 , which is lighter than titanium (about 4.51g / cm 3 ), which can minimize the weight of the shielding member, reduce the load when the carrier 20 lifts the shielding member, and facilitate the taking and placing of the shielding member and maintenance. At the same time, aluminum alloy has excellent electrical conductivity, which is better than titanium, and has a good foundation in ensuring smooth grounding path and maintaining stable electron depletion region, which can meet the demand for electrical conductivity of the shielding member.

[0064] However, the surface of aluminum alloy will naturally form an insulating layer of aluminum oxide, which can easily cause grounding failure.

[0065] The conductive coating refers to a coating for improving electrical conductivity provided at the indirect grounding connection part of the shielding member, mainly including a local nickel plating, gold plating coating, or a coating formed by a special conductive sealing process (such as a nickel salt sealing process).

[0066] The "indirect grounding connection part" of the shielding member refers to a key area for realizing the transmission of grounding current on the shielding member, including an area where the outer edge of the shielding member is in contact with the cavity wall of the coating cavity 10 (a part in contact with the hanging wall 11 when the hanging wall 11 is used), an area where the inner edge of the shielding member is in contact with the wafer or carrier 20, and a preset grounding connection point (a part for conductive connection with the hanging wall 11 or the like) on the shielding member.

[0067] By arranging a conductive coating at the key part of the indirect grounding, the barrier of the aluminum oxide insulating layer can be broken through, and a stable conductive path can be established between the shielding member and the hanging wall 11 or the carrier 20 through the coating, so as to always maintain the potential of the shielding member close to the ground and ensure the stable existence of the electron depletion zone.

[0068] Optionally, the upper plate 1 and the lower plate 2 are detachably connected.

[0069] After long-term use, a large number of particles will be deposited in the labyrinth-type airflow channel. The detachable design can facilitate the staff to detach the upper plate 1 and the lower plate 2, clean the inner wall of the channel, the baffle 3 and other parts, and avoid the blockage of the channel by the particles and the influence of the flow of the reaction gas and the deposition of the particles.

[0070] Meanwhile, if the shielding member is locally damaged, the detachable design does not require the replacement of the entire shielding member, but only the replacement of the damaged plate body, which can greatly reduce the use cost.

[0071] In addition, the upper plate 1, the lower plate 2, the baffle 3, the inlet and outlet holes and other structures can be precisely machined respectively during processing, and then assembled into a shape. Compared with the integral machining of the closed space and the internal structure, the precision of each component can be more easily ensured.

[0072] The present application does not limit the specific detachable connection form of the upper plate 1 and the lower plate 2.

[0073] In an embodiment, a corresponding bolt hole is uniformly arranged on the inner edge and / or the outer edge of the upper plate 1 and the lower plate 2 in the circumferential direction. After the upper plate 1 and the lower plate 2 are aligned, the bolts are inserted into the bolt holes and tightened, so as to realize the stable connection of the two plates. When disassembling, the bolts are only needed to be unscrewed, and then the upper plate 1 and the lower plate 2 can be separated.

[0074] In another embodiment, the inner edge and / or the outer edge of one of the upper plate 1 and the lower plate 2 is provided with a buckle, and the inner edge and / or the outer edge of the other is provided with a clasp. After the two are overlapped, the buckle is used to tighten the clasp, so as to fix the upper plate 1 and the lower plate 2. When disassembling, the buckle is loosened, and then the upper plate 1 and the lower plate 2 can be separated.

[0075] Optionally, the edge part of the upper plate 1 and the lower plate 2 is provided with a corresponding positioning hole and a positioning pin.

[0076] For details, please refer to Figure 5In the illustrated embodiment, the edge portion of the upper surface of the lower plate 2 is provided with at least two positioning holes, and the edge portion of the lower surface of the upper plate 1 is provided with at least two positioning pins, which correspond to the positioning holes one by one. The diameter of the positioning pin is accurately matched with the hole diameter of the positioning hole, and when assembled, the positioning pin can be exactly embedded in the positioning hole.

[0077] The positioning hole and the positioning pin can prevent the upper plate 1 and the lower plate 2 from being misaligned when assembled, ensure that the labyrinth air flow channel between the two has a designed shape, and maintain the preset labyrinth interception effect. In addition, after the cover is disassembled for cleaning or component maintenance each time, the accurate matching of the positioning hole and the positioning pin can quickly restore the assembled state of the upper plate 1 and the lower plate 2, and ensure that the geometric shape (such as the channel width and the tortuosity) of the labyrinth air flow channel is always consistent.

[0078] Optionally, the upper surface of the lower plate 2 is provided with a slot, and the inner edge of the upper plate 1 can be inserted into the slot.

[0079] For details, please refer to Figure 4 In the illustrated embodiment, in the left-right direction, the width of the upper plate 1 is smaller than the width of the lower plate 2, and the inner edge of the right side of the upper plate 1 is lapped on the top of the lower plate 2. The part of the lower plate 2 for contacting the inner edge of the right side of the upper plate 1 is provided with a slot. The inner edge of the upper plate 1 inserted into the slot can form a close connection with the inner wall of the slot, and this part will constitute one side wall of the labyrinth air flow channel.

[0080] Through the insertion and cooperation of the inner edge of the upper plate 1 and the slot, the sealing connection between the two plates can be strengthened, and the escape of reaction gas or mistakenly entered particles from the connection gap between the two plates can be avoided. In addition, the integrity and continuity of the labyrinth air flow channel can be maintained by means of this close cooperation, and the gap caused by the loose connection of the inner edges of the upper and lower plates can be prevented, so that the channel structure is not broken, and the movement track and sedimentation effect of the particles in the channel are not affected.

[0081] Optionally, a sealing ring is arranged between the upper plate 1 and the lower plate 2 to prevent gas or particles from escaping from the connection part of the two plates.

[0082] For details, please refer to Figure 4 In the illustrated embodiment, the outer edge connection position (left side) of the upper plate 1 and the lower plate 2 is provided with a first sealing ring, and the position where the inner edge of the upper plate 1 is connected with the slot of the lower plate 2 is provided with a second sealing ring. In order to facilitate the placement of the sealing ring, an annular sealing ring groove is further arranged between the upper plate and the lower plate, and the sealing ring is made of perfluoroether rubber or fluororubber. After being embedded in the sealing ring groove, when the upper plate 1 is closed on the lower plate 2, the sealing ring is pressed to form a tight sealing structure between the two plates, which can prevent gas and particles from escaping or mistakenly entering from the connection position of the upper and lower plates.

[0083] Optionally, a conductive ring is further arranged between the upper plate 1 and the lower plate 2 to realize the electrical connection of the upper plate 1 and the lower plate 2.

[0084] The conductive ring is arranged inside the sealing ring and is made of conductive material (such as copper alloy, silver-plated copper alloy, etc.). When the upper plate 1 is covered on the lower plate 2, the two will jointly compress the conductive ring and tightly adhere to it, thereby forming a stable connection structure between the upper and lower plates to realize electrical conduction.

[0085] The conductive ring can establish a low-resistance electrical path between the upper and lower plates, ensuring reliable electrical connection between the upper plate 1 and the lower plate 2. Even if the cover is disassembled and reassembled several times, the conductive ring can still maintain good electrical connection state due to its material properties (such as the excellent elasticity of beryllium copper alloy and the good conductivity of silver-plated copper alloy).

[0086] The present application does not limit the specific configuration of the conductive ring, as long as it can adhere to the upper and lower plates to achieve electrical connection.

[0087] In one embodiment, the conductive ring is made of beryllium copper alloy and has a ring structure with a C-shaped cross-section. The upper and lower plates are provided with a ring-shaped conductive ring mounting groove. After the upper and lower plates are covered, the conductive ring in the conductive ring mounting groove is compressed and elastically deformed. The deformed C-shaped conductive ring will tightly adhere to the upper plate 1 and the lower plate 2, and rely on the high conductivity and elastic recovery force of beryllium copper alloy to achieve low-resistance and durable electrical connection between the upper and lower plates.

[0088] In another embodiment, the conductive ring is made of silver-plated copper alloy and has a ring structure with a U-shaped cross-section. After the upper and lower plates are covered, the upper plate 1 will compress the top horizontal bar of the U-shaped conductive ring, causing the two side walls of the U-shaped conductive ring to slightly expand outward, further enhancing the tightness of its contact with the conductive ring mounting groove and the lower surface of the upper plate 1. The silver plating layer can effectively reduce the contact resistance, and the copper alloy can ensure the structural strength and basic conductivity, thereby realizing stable electrical connection between the upper and lower plates.

[0089] The complete set of design of positioning hole and positioning pin, embedding groove, sealing ring and conductive ring arranged in the detachable connection of the upper plate and the lower plate solves the problems of assembly misplacement (the cooperation of the positioning hole and the positioning pin can prevent the assembly misplacement of the upper plate and the lower plate, ensure that the internal structure is always accurately aligned and keeps the design state), sealing failure (the insertion of the inner edge of the upper plate 1 into the embedding groove of the lower plate 2, in cooperation with the sealing ring, can completely block the escape of gas or particles from the connection gap between the two plates), and conductive interruption (the conductive ring establishes a low-resistance and high-reliability electrical connection between the upper plate and the lower plate, which can still maintain stability even after multiple disassembly and assembly, ensures that the upper plate 1 and the lower plate 2 have the same potential, and thus the grounding potential of the whole shade is stable, ensuring the continuous effectiveness of the electron depletion zone), and ensures that the upper plate and the lower plate can completely restore the core structural function of the shade after assembly, that is, maintaining the design integrity and stability of the labyrinth air flow channel, ensuring the electrical connection reliability required for the grounding of the shade, and completely preventing gas or particles from leaking from the connection part.

[0090] In a specific embodiment, the conductive ring is an elastic metal spring made of beryllium copper alloy or silver-plated copper alloy; the cross-sectional shape of the conductive ring is C-shaped, U-shaped or Ω-shaped; the lower surface of the upper plate 1 and / or the upper surface of the lower plate 2 is provided with an annular groove for accommodating the conductive ring, and the conductive ring is fixed in the annular groove by interference fit and is pressed between the upper plate 1 and the lower plate 2; the conductive ring can provide continuous contact pressure by elastic deformation, so as to resist the surface oxidation, microscopic unevenness and thermal deformation of the plate, thereby maintaining the electrical path between the upper plate 1 and the lower plate 2.

[0091] Specifically, the conductive ring is made of beryllium copper alloy or silver-plated copper alloy, and the cross-sectional shape can be C-shaped, U-shaped or Ω-shaped. Meanwhile, an annular groove adapted to the conductive ring is provided on the lower surface of the upper plate 1 and / or the upper surface of the lower plate 2, which is used to accommodate the conductive ring, so as to ensure that the conductive ring can stably stay in the preset position and keep contact with the upper and lower plates.

[0092] More specifically, the conductive ring is fixed in the annular groove by interference fit, which can preliminarily fix the conductive ring in the annular groove and avoid displacement before assembly. When the upper plate 1 is covered on the lower plate 2, the conductive ring will be pressed between the upper plate 1 and the lower plate 2, causing slight elastic deformation of the elastic metal spring.

[0093] The elastic metal spring can provide a continuous contact pressure through elastic deformation. The continuous contact pressure can effectively resist surface oxidation, micro-unevenness, and thermal deformation due to temperature changes during operation of the plating device, which can occur in the contact surface of the upper plate and the lower plate during long-term use, to prevent these factors from causing a gap between the upper plate and the lower plate, increasing the contact resistance, or even interrupting the connection, so as to always maintain the electrical path between the upper plate 1 and the lower plate 2, and ensure that the entire shielding member has a long-term stable grounding potential, thereby providing the necessary electrical basis for the stable maintenance of the electron depletion region.

[0094] In an embodiment, the baffle 3 includes an upper baffle arranged on the lower surface of the upper plate 1 and a lower baffle arranged on the upper surface of the lower plate 2. Both the upper baffle and the lower baffle are annular structures coaxial with the shielding member. The upper baffle and the lower baffle are staggered and spaced along the radial direction of the shielding member. The number of baffles 3 is at least three. The distance between any two adjacent baffles 3 is 2-8 mm.

[0095] For details, please refer to Figure 3 and Figure 4 In the illustrated embodiment, the baffle 3 includes an upper baffle and a lower baffle. The upper baffle is fixedly arranged on the lower surface of the upper plate 1, and the lower baffle is fixedly arranged on the upper surface of the lower plate 2. Both the upper baffle and the lower baffle are annular structures coaxial with the overall annular structure of the shielding member, which is suitable for the circumferential shape of the shielding member.

[0096] Continuing to refer to Figure 3 and Figure 4 The upper baffle and the lower baffle are staggered and spaced along the radial direction of the shielding member (left-right direction in the figure). They are staggered and misaligned in the radial direction of the shielding member. At the same time, any two adjacent baffles 3 (i.e., an adjacent upper baffle and a lower baffle) maintain an orderly interval. The two types of baffles together build a tortuous structural basis for the labyrinth air flow channel in the closed space.

[0097] It should be explained that the number of baffles 3 is limited to at least three to ensure that a labyrinth air flow channel with sufficient tortuosity is formed in the closed space. If the number of baffles is less than three, the number of bends in the channel is too small, and the path is relatively simple. The particles that mistakenly enter from the air outlet hole 1a can pass through the channel after only a few collisions, which cannot sufficiently dissipate kinetic energy and cannot effectively achieve sedimentation interception. At least three baffles 3 are staggered and distributed to form multiple bends, allowing particles to repeatedly change direction in the channel, collide with the baffles 3, and gradually dissipate kinetic energy, and finally settle in the channel.

[0098] It also needs to be explained that the reason for limiting the "distance between any two adjacent baffles 3 to 2-8mm" is to ensure smooth flow of the reaction gas while taking into account the labyrinth-type airflow passage's interception effect on particles. If the distance is too small (<2mm), it will greatly increase the flow resistance of the airflow in the passage, affecting the uniform delivery and flow stability of the reaction gas, and even possibly causing the passage to be blocked. If the distance is too large (>8mm), the distance of the particle movement between adjacent baffles 3 is too long, and there is enough space to maintain kinetic energy or change the direction of movement to avoid impact, making it difficult to ensure the full consumption of kinetic energy. The 2-8mm distance range can not only let the reaction gas flow smoothly, but also ensure that particles are easy to collide and gradually consume kinetic energy when moving between adjacent baffles 3, achieving a balance between airflow flow and particle interception.

[0099] Optionally, in the closed space, the vertical distance between the upper baffle and the upper surface of the lower plate 2 is H1, and the vertical distance between the lower baffle and the lower surface of the upper plate 1 is H2, the value range of H1 and H2 is 0.5-2mm, and H1

[0100] The value range of H1 and H2 is 0.5-2mm, which is based on the trade-off between particle blocking efficiency and gas flow resistance, and is determined comprehensively in combination with actual process requirements, processing feasibility, and synergy with other structures of the shielding piece.

[0101] Specifically, the lower limit is set to 0.5mm because this size can be stably achieved and the tolerance can be accurately controlled in mechanical processing, which is small enough to form an effective physical barrier for nano to sub-micron particles (such as sputtered metal atom / ion groups, which move in Brownian motion), making it easy for particles to collide with the passage wall and be captured, and can also use the high-speed airflow in the narrow passage to form a "sweeping" effect to prevent particles from settling on the side of the baffle 3, while leaving a safety margin for thermal expansion of the material during process heating to avoid contact and jamming or damage of the upper baffle and the lower plate 2, and the lower baffle and the upper plate 1 due to thermal deformation.

[0102] The upper limit is set to 2mm, on the one hand to maintain design logic consistency with the 0-2mm gap upper limit between the shielding piece outer edge and the coating chamber wall, and on the other hand to avoid the risk of particle escape due to excessive distance (when the distance exceeds 2mm, particles with high kinetic energy or strong directionality are easy to pass through the passage without sufficient collision), while balancing airflow resistance to avoid excessive pressure drop on the gas pump and sealing system, and reducing the parallelism of the upper and lower plates, reducing the processing difficulty of the baffle 3, improving the assembly fault tolerance, and better adapting to the gas flow state between viscous flow and molecular flow in the PVD vacuum environment, ensuring frequent collisions between particles, gas molecules, and passage walls.

[0103] H1 is set to be less than H2 in order to combine the movement trend of the deposited particles, further optimize the interception effect and air flow circulation. Since most of the particles that enter the labyrinth air flow channel are moving from top to bottom, H1, as the vertical distance between the upper baffle and the upper surface of the lower plate 2, is the first "threshold" for particles entering the channel. Smaller H1 can intercept most of the particles moving from top to bottom near the entrance with a more stringent gap, reducing the amount of particles that need to be processed subsequently from the source. While H2 is slightly larger, it can avoid the situation where the total resistance of the channel increases dramatically due to too small gaps, affecting the smooth flow of reaction gas. While ensuring high efficiency of particle interception, it also considers the stability of air flow circulation.

[0104] Optionally, the inner wall of the labyrinth air flow channel is coated with a polytetrafluoroethylene anti-adhesion coating, which can change the adhesion state of the particles in the labyrinth air flow channel, from hard scaling to loose accumulation.

[0105] The polytetrafluoroethylene anti-adhesion coating covers all the walls in the labyrinth air flow channel that may come into contact with the reaction gas and particles, ensuring that the coating forms a continuous and complete anti-adhesion layer without missing areas to cover the entire path of particle impact and sedimentation.

[0106] Relying on the extremely low surface energy characteristics of polytetrafluoroethylene, the adhesion state of particles in the channel can be changed. Specifically, after particles lose kinetic energy by hitting the baffle 3 in the channel, they will still settle down, but unlike on bare metal walls, they will not form hard scaling that is firmly combined with the substrate or previously deposited particles. Instead, they will stay in loose accumulation or physical storage at the bottom or corners of the channel. This change can ensure that particles are effectively trapped in the channel and do not follow the gas flow into the reaction area to contaminate the wafer. On the other hand, it can avoid hard scaling changing the channel geometry (such as narrowing the key gap), affecting the air flow field and the interception efficiency of particles. It can also greatly simplify the later maintenance and cleaning process (after disassembling the upper and lower plates, only a vacuum cleaner, high-pressure gas or a dust-free cloth is needed to easily remove the loose accumulated particles, while eliminating the risk of secondary particle contamination caused by hard scaling layer peeling due to thermal stress or vibration). Ultimately, it maintains the reliability of the shielding performance in the long term.

[0107] Optionally, the thickness of the polytetrafluoroethylene anti-adhesion coating is 10-20 μm.

[0108] Setting the thickness of the polytetrafluoroethylene anti-adhesion coating to 10-20 μm is the result of comprehensive consideration of anti-adhesion effect, adaptation to the structure of the labyrinth air flow channel, and consideration of process feasibility and long-term stability.

[0109] 10 μm is the lower limit for forming a continuous and complete anti-adhesion layer. Below this thickness, uneven spraying process may cause defects such as micropores and missing coating, resulting in loss of anti-adhesion properties in some areas of the channel wall, and particles may still form hard scaling in these areas.

[0110] The upper limit of 20 pm is to avoid the coating being too thick to reduce the effective cross-sectional area of the labyrinth gas flow channel, especially the critical narrow gap (such as H1, H2 of 0.5-2 mm) in the channel. If the coating is too thick, it will change the original geometry of the channel, affect the flow resistance and flow rate stability of the reaction gas, and even cause local blockage of the channel, interfering with the design effect of particle impact interception.

[0111] At the same time, this thickness range can adapt to the temperature fluctuations in the coating process. Although the thermal expansion coefficient of polytetrafluoroethylene is relatively high, the thickness of 10-20 pm can compensate for the thermal expansion difference between itself and the metal substrate (such as titanium alloy, aluminum alloy) through its own elastic deformation, avoiding stress-induced cracking or peeling of the coating due to temperature changes, and being able to withstand the kinetic energy of particle impact. It will not be easily damaged by particles due to being too thin, nor will it increase the risk of adhesion between the coating and the substrate due to being too thick.

[0112] In addition, 10-20 pm meets the process precision of conventional electrostatic spraying or suspension spraying, and can uniformly cover the inner wall and corners of the channel. The thickness tolerance is easy to control within a reasonable range, ensuring the overall consistency of the coating. During later maintenance, the smooth surface of the coating of this thickness allows loose particles to be easily removed by a vacuum cleaner or high-pressure airflow, without particles being embedded in deep pits due to the coating being too thick, making it difficult to clean. Ultimately, a balance is achieved between anti-sticking performance, structural adaptability, process implementation, and maintenance convenience, ensuring that the labyrinth gas flow channel can stably perform particle interception functions for a long time.

[0113] Optionally, the bottom of the labyrinth gas flow channel is provided with an arc-shaped groove, which is located on the downstream side of the baffle 3 or the outer side of the gas flow turning position, which can maximize the settling efficiency in the low-speed area and guide and concentrate particles in the designated area.

[0114] It needs to be explained that the labyrinth gas flow channel simultaneously performs the functions of gas inlet and outlet. The coating cavity 10 is provided with an air inlet and an air outlet, and the air outlet is connected to a negative pressure device for controlling the air pressure in the cavity. The air inlet and the air outlet are both arranged below the baffle. During the coating process, the newly input reaction gas enters the reaction area through the labyrinth gas flow channel, and at the same time, the unreacted gas and by-products can also leave the reaction area through the labyrinth gas flow channel and be removed by the negative pressure device.

[0115] The zigzag path and the spaced distribution of the baffles 3 of the labyrinth gas flow channel naturally form a spatial stratification. After the reaction gas enters from the air inlet hole 2a, it flows upward along the main path of the labyrinth gas flow channel and finally uniformly enters the reaction area through the air outlet hole 1a. The gas that does not participate in the reaction flows downward along the gap of the baffles 3 in the channel or in the area that is staggered with the air inlet path under the negative pressure action of the negative pressure device, and finally is discharged.

[0116] In this design, the upward driving force of the inlet gas and the downward suction force of the outlet gas form a clear pressure gradient, and the labyrinth structure also has a damping effect, which can make the two gas flows flow in layers in the channel without interfering with each other, ensuring uniform supply of reaction gas and efficient exhaust of waste gas. The tortuosity of the channel can also make the deposited particles collide and settle in the smooth environment of the two-way gas flow, and the particles will not be disturbed due to the different directions of the gas flow, so the channel can fully perform the functions of inlet and outlet gas.

[0117] It should also be explained that the downstream side of the baffle 3 refers to the area on the side where the particles continue to flow after colliding with the baffle 3 in the labyrinth gas flow channel, that is, the area behind the baffle 3 reached by the particles after colliding with the baffle 3 and the initial consumption of kinetic energy.

[0118] The outer side of the gas flow turning point refers to the area on the side away from the turning center along the turning track of the gas flow when the gas flow changes direction in the labyrinth gas flow channel, such as changing from horizontal to vertical or turning along the annular channel. It is also the outer space formed by the bending of the path when the gas flow turns.

[0119] The reason for placing the arc-shaped grooves at these two positions is that these two places are the areas where particles are most likely to lose kinetic energy and aggregate. After colliding with the baffle 3, the particles' kinetic energy is greatly reduced, and they are difficult to continue moving in the downstream side due to gravity. When the gas flow turns, the particles will maintain their original straight motion due to inertia, and will be thrown to the outer side of the turning, away from the main gas flow, and will fall into the arc-shaped grooves on the outer side. The placement of these two positions maximizes the capture efficiency of the arc-shaped grooves for particles.

[0120] In addition, due to the deviation of the arc-shaped grooves from the main gas flow path of the labyrinth gas flow channel, the flow channel environment causes the gas flow to diffuse or be blocked, so the gas flow rate inside the arc-shaped grooves is much lower than that in the main flow area, which provides an ideal low-speed environment for the settlement of particles, avoiding the particles being re-voluted by the gas flow, and guiding and concentrating the particles dispersed in the channel to these designated areas, avoiding the particles randomly scattered at the bottom of the channel. The converging structure of the edge of the arc-shaped groove can further block the settled particles from leaving the groove, helping the particles to stay in the designated area stably and not disturbing the normal gas flow path and particle interception function of the labyrinth gas flow channel.

[0121] In an embodiment, the inner edge of the cover is arranged in a stepped shape, including a first inclined surface 1b formed by the inner edge of the upper plate 1, a second inclined surface 2d formed by the inner edge of the lower plate 2, and a horizontal connecting surface 2e formed by the upper surface of the lower plate 2 between the first inclined surface 1b and the second inclined surface 2d. The second inclined surface 2d can capture particles that are incident at a large angle and would otherwise be deposited in the edge region of the wafer. The first inclined surface 1b and the horizontal connecting surface 2e can tighten the opening exposed to the target material, ensuring that the center area of the wafer that needs to be coated is exposed to the particle flow.

[0122] Specifically refer to Figure 4 In the illustrated embodiment, the stepped inner edge of the shield is composed of three mutually connected structures, the first part is the first inclined surface 1b integrally formed on the inner edge of the upper plate 1, the second part is the second inclined surface 2d integrally formed on the inner edge of the lower plate 2, and the third part is the horizontal connecting surface 2e formed by extending the upper surface of the lower plate 2 between the first inclined surface 1b and the second inclined surface 2d, which together form a stepped structure gradually transitioning from the shield to the wafer, from top to bottom.

[0123] Among them, the second inclined surface 2d can accurately capture particles with large-angle oblique incidence, which may otherwise be deposited on the edge area of the wafer, and by capturing it can avoid unnecessary film formation on the edge and back of the wafer, which is crucial for the smooth development of subsequent photolithography and etching processes and the stability of chip performance.

[0124] The first inclined surface 1b and the horizontal connecting surface 2e cooperate with each other to tighten the opening exposed below the target material, accurately define a stable "deposition window", and ensure that the center area of the wafer that needs to be coated is exposed to the particle flow in the deposition window, while creating a wider "shadow area" for the edge of the wafer, further eliminating ineffective deposition.

[0125] At the same time, the stepped inner edge of the shield serves as the last hurdle for the reaction gas flowing out of the labyrinth-type gas flow channel through the gas outlet hole 1a into the deposition window. The gradually expanding inclined surface shape allows the gas to turn and diffuse more smoothly above the wafer, thereby avoiding the formation of vortexes near the edge of the wafer (vortexes can cause uneven film thickness and may roll up the deposited particles, causing secondary contamination).

[0126] Further, by fine-tuning the angle of the inclined surface, the flow rate and distribution of the gas on the wafer surface can be adjusted, promoting the uniformity of film deposition.

[0127] In addition, compared to thick vertical inner walls, the inclined surface structure can significantly reduce the weight of the shield while ensuring sufficient structural strength, meeting the design goal of lightweight, easy to be lifted, and not easily crushing the wafer. The geometry can further enhance the heat deformation resistance of the shield, ensuring the structural stability of the shield in long-term use and ensuring that the stepped shape and function of the inner edge of the shield are not easily damaged by temperature changes.

[0128] Optionally, the inner edge of the shield for abutting against the end of the wafer is provided with a circular arc chamfer, and the radius of the circular arc chamfer is 0.5-1.5mm, which is used to reduce the contact area between the lower plate 2 and the wafer, and avoid sticking.

[0129] Specifically refer to Figure 4In the illustrated embodiment, the inner edge of the lower plate 2 used to abut against the end of the wafer (i.e. the lower right corner of the lower plate 2) is rounded, and the chamfer is in the form of a smooth and continuous circular arc with a radius strictly controlled within the range of 0.5-1.5 mm. This can make the shielding member used to abut against the end of the wafer transition from the originally possible sharp edge or right angle to a rounded arc structure, so as to ensure the formation of a smooth contact interface when in contact with the wafer, rather than a rigid sharp contact.

[0130] The circular arc chamfer can reduce the contact area between the lower plate 2 and the wafer, and even enable the shielding member to shield the edge of the wafer without contacting the wafer. In this way, even if a small number of deposited particles adhere to the area close to each other, it is difficult to form a force sufficient to cause adhesion between the two, so as to effectively avoid the adhesion between the shielding member and the wafer after the process is completed, and ensure that the shielding member can be separated from the wafer after the film is completed.

[0131] The stepped inner edge of the shielding member cooperates with the circular arc chamfer to precisely control the deposition area of the particles, ensure the smoothness of the process operation and the safety of the structure of the wafer. The stepped inner edge can capture particles that are incident at a large angle through the second slope 2d, so as to avoid the deposition of the particles in the edge area of the wafer to form an invalid film. Meanwhile, the first slope 1b and the horizontal connecting surface 2e together tighten the opening of the deposition window to strictly limit the deposition range, so as to ensure that the central area of the wafer that needs to be coated is precisely exposed to the particle flow to achieve precise coating and edge protection. The circular arc chamfer provided at the end of the wafer used to abut against the wafer can effectively avoid the adhesion between the lower plate 2 and the wafer due to the deposition of particles by reducing the contact area between the two, which helps to separate the shielding member from the wafer. Meanwhile, the smooth circular arc shape can also avoid scratching the edge of the wafer by the sharp end, which helps to ensure the integrity of the structure of the wafer. The two cooperate to precisely control the deposition of particles through the stepped inner edge, and solve the adhesion and damage problems at the contact position through the circular arc chamfer, so that the shielding member can play the role of precise coating assistance while taking into account the convenience of process operation and the safety of the wafer.

[0132] Optionally, a plurality of gas outlet holes 1a are provided on the upper plate 1, and the plurality of gas outlet holes 1a are equally spaced in the circumferential direction. A plurality of gas inlet holes 2a are provided on the lower plate 2, and the plurality of gas inlet holes 2a are also equally spaced in the circumferential direction. The number of the gas inlet holes 2a is greater than the number of the gas outlet holes 1a, and the total flow area of the gas inlet holes 2a is greater than the total flow area of the gas outlet holes 1a, so as to establish a uniform and stable back pressure in the labyrinth-type airflow channel, ensure the uniformity of the flow of the reaction gas, and avoid the disturbance of the high-speed airflow to the stability of the plasma in the reaction area.

[0133] The reason for limiting the number of the air inlet holes 2a to be more than the number of the air outlet holes 1a and the total flow area of the air inlet holes 2a to be larger than the total flow area of the air outlet holes 1a is to achieve the optimization of the air flow path structure, the uniform distribution of the gas, the establishment of the stable back pressure and the intensification of the particle deposition at the same time.

[0134] Specifically, more air inlet holes 2a can allow the reaction gas to have a more dispersed inlet when entering the labyrinth air flow channel, reduce the initial flow distance of the gas in the channel, make it quickly and uniformly fill the entire annular channel, and have a lower flow rate of each air inlet hole 2a under the same total flow, which can avoid the vortex of high-speed gas in the channel and the rolling up of the already deposited particles.

[0135] And the smaller total flow area of the air outlet holes 1a forms a "bottleneck" for the gas to flow out, which can establish a uniform and stable back pressure inside the labyrinth air flow channel, which can drive the gas to flow out uniformly from each air outlet hole 1a, avoid the gas from flowing out from part of the air outlet holes 1a, cause the uneven gas flow above the wafer, and reduce the flow rate of the gas entering the reaction area to prevent the high-speed gas from impacting the wafer surface or disturbing the plasma.

[0136] In addition, this structure can also cooperate with the tortuous path of the labyrinth air flow channel to prolong the residence time of the gas in the channel, reduce the drag force of the gas on the particles, and allow the particles to have more opportunities to collide with the baffles 3 and deposit under the action of gravity.

[0137] Optionally, the air inlet holes 2a are arranged in a trumpet shape, the hole diameter of the air inlet holes 2a is larger away from the upper plate 1, and the expansion angle of the air inlet holes 2a is 45°-60°, so as to guide the reaction gas to enter the labyrinth air flow channel uniformly.

[0138] The air inlet holes 2a are arranged in a trumpet shape so that the reaction gas can obtain a more gentle and more divergent flow path when entering the labyrinth air flow channel from the outside of the shielding member, avoiding the gas from directly impacting the inside of the channel in a concentrated columnar flow, thereby guiding the gas to uniformly diffuse to all directions at the initial stage of entering the channel, reducing the local flow rate difference or vortex caused by the concentrated gas flow, and ensuring that the gas can quickly and uniformly fill the entire labyrinth air flow channel.

[0139] The reason why the expansion angle of the air inlet hole 2a is limited to 45°-60° is that this angle range can uniformly diffuse the guided airflow, avoid airflow turbulence, and take into account the processing feasibility. Specifically, if the expansion angle is less than 45°, the degree of divergence of the horn mouth is insufficient, the guiding effect of the airflow is limited, and the gas may still enter the channel in a relatively concentrated form, making it difficult to achieve uniform diffusion, and even a local high-speed flow may be generated due to the excessive constraint of the hole wall on the airflow. If the expansion angle is greater than 60°, the degree of divergence of the horn mouth is too large, which on the one hand increases the processing difficulty of the air inlet hole (especially the forming precision of the hole wall in the thickness direction of the lower plate), and on the other hand, the excessively wide hole port is easy to cause the airflow to form backflow or disordered diffusion in the hole, thereby disturbing the stability of the airflow entering the channel, and even the particles settled at the bottom of the channel may be rolled up, affecting the particle interception effect of the labyrinth type airflow channel. The expansion angle of 45°-60° can effectively guide the airflow to diffuse gently in all directions, ensure the uniformity of the gas entering, and avoid processing difficulties and airflow turbulence problems, ensuring that the air inlet hole can stably play a role in guiding the gas to enter the labyrinth type airflow channel uniformly.

[0140] The above embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it cannot be understood as limiting the scope of the patent application. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the scope of protection of the present application. Therefore, the scope of protection of the patent of the present application should be subject to the appended claims.

Claims

1. A particle deposition shield for a coating apparatus, disposed within a coating chamber (10), characterized in that, The application relates to a particle deposition prevention shield for a coating equipment, which comprises an upper plate (1) and a lower plate (2) arranged in a ring shape, the upper plate (1) is connected with the lower plate (2), and a closed space is formed between the upper plate (1) and the lower plate (2). A plurality of baffles (3) are arranged in the closed space in an upper-lower staggered and interval arrangement mode, the baffles (3) can complicate the flow path of gas in the closed space, and the closed space is constructed into a labyrinth type gas flow channel. A gap with a size of 0-2mm exists between the outer edge of the shield and the inner wall of the coating cavity (10), the cavity wall of the coating cavity (10) is grounded, and the gap is constructed into an electron depletion zone mainly with positive charges. An air inlet hole (2a) is arranged on the lower plate (2), and an air outlet hole (1a) is arranged on the upper plate (1). When the coating equipment works, the carrier (20) carries the wafer upwards and lifts the shield, the reaction gas enters the labyrinth type gas flow channel through the air inlet hole (2a) and then flows out from the air outlet hole (1a) and enters the reaction area. The particles entering the labyrinth type gas flow channel through the air outlet hole (1a) will finally lose kinetic energy and sink in the labyrinth type gas flow channel due to the impact of the baffles (3) caused by the channel tortuosity. The particles entering the electron depletion zone will be limited due to the strong electric field force and the charge separation characteristics, and finally lose activity or cannot break through the gap. The labyrinth type gas flow channel and the electron depletion zone cooperate to limit the movement range of the particles and avoid the pollution of the carrier (20) or the lower cavity, so that the stability of the coating process and the preparation yield of the film are ensured.

2. The particle deposition shield for a coating apparatus of claim 1, wherein, The inner wall of the coating cavity (10) is provided with a hanging wall (11) extending to the center of the cavity, and the hanging wall (11) is used for supporting the shield. A plurality of elastic conductive members are arranged on the hanging wall (11) and are distributed in the circumferential direction at equal intervals, the elastic conductive members are compressed and electrically connect the shield and the cavity wall of the coating cavity (10) when the shield is arranged on the hanging wall, and the shield and the cavity wall are electrically connected in an equipotential mode.

3. The particle deposition shield for a coating apparatus of claim 2, wherein, The outer edge of the lower surface of the lower plate (2) is provided with a groove (2b), and the hanging wall (11) is inserted into the groove (2b) when the shield is arranged on the hanging wall (11). A step structure (2c) is arranged in the inner side region corresponding to the groove (2b) in the labyrinth type gas flow channel, the step structure (2c) extends in a ladder shape and forms at least one convex step to increase the tortuosity of the labyrinth type gas flow channel. The horizontal step surface of the step faces the air outlet hole (1a), and the spacing between the horizontal step surface and the air outlet hole (1a) is smaller than the channel width of the main body section of the labyrinth type gas flow channel, so as to reduce the activity space of the mistaken particles and accelerate the kinetic energy depletion of the mistaken particles.

4. The particle deposition prevention shield for the coating equipment according to claim 1, wherein the shield is made of titanium or titanium alloy. Alternatively, the shield is made of aluminum alloy, and an electrically conductive coating is arranged on the indirect grounding connection part of the shield.

5. The particle deposition shield for a coating apparatus as set forth in claim 1 or 4, wherein The upper plate (1) and the lower plate (2) are detachably connected. The edge part of the upper plate (1) and the lower plate (2) is provided with a corresponding positioning hole and positioning pin; The upper surface of the lower plate (2) is provided with an embedded groove, and the inner edge of the upper plate (1) can be inserted into the embedded groove; A sealing ring is arranged between the upper plate (1) and the lower plate (2) to prevent gas or particles from escaping from the connecting part of the two; A conductive ring is further arranged between the upper plate (1) and the lower plate (2) to realize the electrical connection of the upper plate (1) and the lower plate (2).

6. The particle deposition shield for a coating apparatus of claim 5, wherein, The conductive ring is an elastic metal spring made of beryllium copper alloy or silver plated copper alloy; The cross-sectional shape of the conductive ring is C-shaped, U-shaped or Ω-shaped; The lower surface of the upper plate (1) and / or the upper surface of the lower plate (2) is provided with an annular groove for accommodating the conductive ring, and the conductive ring is fixed in the annular groove by interference fit and is pressed between the upper plate (1) and the lower plate (2); The conductive ring can provide continuous contact pressure by elastic deformation to resist the surface oxidation, microscopic unevenness and thermal deformation of the plate, thereby maintaining the electrical connection between the upper plate (1) and the lower plate (2).

7. The particle deposition shield for a coating apparatus of claim 1, wherein, The baffle (3) includes an upper baffle arranged on the lower surface of the upper plate (1) and a lower baffle arranged on the upper surface of the lower plate (2), and the upper baffle and the lower baffle are both annular structures coaxial with the shield; The upper baffle and the lower baffle are staggered and spaced along the radial direction of the shield; The number of baffles (3) is at least 3; The distance between any two adjacent baffles (3) is 2-8mm; In the closed space, the vertical distance between the upper baffle and the upper surface of the lower plate (2) is H1, and the vertical distance between the lower baffle and the lower surface of the upper plate (1) is H2, the value range of H1 and H2 is 0.5-2mm, and H1 < H2.

8. The particle deposition shield for a coating apparatus of claim 1, wherein, The inner wall of the labyrinth type gas flow channel is coated with a polytetrafluoroethylene anti-sticking coating, which can change the adhesion state of particles in the labyrinth type gas flow channel, from hard fouling to loose accumulation; And / or, the bottom of the labyrinth type gas flow channel is provided with an arc-shaped groove, which is located on the downstream side of the baffle (3) or the outer side of the gas flow turning place, which can maximize the settling efficiency in the low-speed area and guide and concentrate the particles in the specified area.

9. The particle deposition shield for a coating apparatus of claim 1, wherein, The inner edge of the shield is arranged in a stepped shape, including a first inclined surface (1b) formed by the inner edge of the upper plate (1), a second inclined surface (2d) formed by the inner edge of the lower plate (2), and a horizontal connecting surface (2e) formed by the upper surface of the lower plate (2) between the first inclined surface (1b) and the second inclined surface (2d); The second inclined surface (2d) can capture particles that are originally likely to be deposited in the edge area of the wafer due to large-angle oblique incidence; The first inclined surface (1b) and the horizontal connecting surface (2e) can tighten the opening exposed to the target material, and ensure that the center area of the wafer that needs to be coated is exposed to the particle flow; The inner edge of the cover is provided with a circular arc chamfer for abutting against the end of the wafer, the radius of the circular arc chamfer is 0.5-1.5 mm, for reducing the contact area between the lower plate (2) and the wafer, avoiding the adhesion of the two.

10. The particle deposition shield for a coating apparatus of claim 1, wherein, The upper plate (1) is provided with a plurality of air outlet holes (1a), a plurality of the air outlet holes (1a) are equally spaced along the circumferential direction, the lower plate (2) is provided with a plurality of air inlet holes (2a), a plurality of the air inlet holes (2a) are also equally spaced along the circumferential direction, the number of the air inlet holes (2a) is more than the number of the air outlet holes (1a), and the total flow area of the air inlet holes (2a) is greater than the total flow area of the air outlet holes (1a), so as to establish a uniform and stable back pressure in the labyrinth type air flow channel, ensure the uniformity of the reaction gas flow, and avoid the disturbance of the high-speed gas flow to the plasma stability of the reaction area. And / or, the air inlet holes (2a) are provided in a horn shape, the larger the hole diameter of the air inlet holes (2a) is, the farther away from the upper plate (1), and the expansion angle of the air inlet holes (2a) is 45°-60°, so as to guide the reaction gas to enter the labyrinth type air flow channel uniformly.

Images