A pécvd chamber backplate

Abstract

The application discloses a PECVD chamber back plate, and relates to the technical field of semiconductor manufacturing equipment, which comprises a substrate, an upper surface of the substrate is provided with an air inlet hole; a plurality of air distribution mechanisms are rotatably arranged on a lower surface of the substrate and are distributed along the circumference of the substrate, the air distribution mechanisms have two air flow channel structures, namely an air outlet hole and an air outlet groove; and a driving mechanism is arranged on the substrate and used for driving the plurality of air distribution mechanisms to synchronously rotate so as to switch different air flow channel structures to a working position. The application integrates the two air flow channel structures on the same back plate through the rotatable air distribution mechanism. In the deposition stage, the micro-hole exhaust mode is switched to realize low-pressure laminar uniform air injection and guarantee the consistency of film thickness; in the cleaning stage, the wide-groove exhaust mode is switched to generate high-energy scouring airflow. The structural design can meet the different requirements of the deposition process and the cleaning process for the flow field on the same hardware.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing equipment technology, and more specifically to a PECVD chamber backplane. Background Technology

[0002] PECVD (Plasma Enhanced Chemical Vapor Deposition) technology is a core process in semiconductor, flat panel display, and photovoltaic manufacturing, primarily used to deposit various functional thin films such as silicon nitride and silicon oxide on substrate surfaces. The backing plate, a crucial component of the PECVD process chamber, is located between the gas inlet and the diffuser, playing a vital role in supporting the chamber structure, bearing electrode pressure, and precisely distributing process gases. In existing technologies, the backing plate is typically formed into airflow pathways through machining (such as gun drilling or angled hole machining) or nested channels. To improve the uniformity of gas distribution, existing technologies often employ gradient aperture designs or add a flow divider at the center of the backing plate, aiming to shorten the diffusion time of process gases from the central inlet to the four corners of the chamber, thereby improving film uniformity and reducing initial gas waste to some extent.

[0003] However, research and development and production practices show that current PECVD chamber backplates still face serious compatibility challenges in terms of flow field control. For example, the Korean patent with patent number 10-2025-0010693, entitled "Backplate and its Mounted Substrate Processing Device," etc. Figure 1 As shown, in this backplate structure, the gas injection holes (airflow channels) used in the deposition and cleaning stages are completely identical and have a fixed physical structure. However, in the actual process flow, the flow field requirements of the two stages are fundamentally different: in the deposition stage, to ensure a high degree of uniformity in the thickness of the nanoscale film, the gas flow is required to be sprayed vertically onto the substrate in a uniform laminar flow with stable pressure and low velocity; while in the plasma cleaning stage (usually using etching gas), the process goal is to quickly and thoroughly remove accumulated byproducts from the chamber edges, the back of the diffuser, and the dead corners of the support. This requires the gas flow to have extremely high velocity, strong kinetic energy scouring force, and a rotating flow field or large-angle jet vector capable of covering the edge areas. Since the existing backplate's pore structure cannot be dynamically adjusted, if the pore size is reduced to meet the deposition uniformity, it will lead to limited gas flow in the cleaning stage, inadequate scouring of edge dead zones, resulting in a significant increase in cleaning time and waste of expensive cleaning gas; conversely, if the flow field direction is changed to improve cleaning efficiency, it will disrupt the laminar flow stability of the deposition stage, leading to a decrease in film quality. Summary of the Invention

[0004] The purpose of this invention is to provide a PECVD chamber backplate that solves the problem of contradiction between the uniformity of laminar flow during the deposition stage and the strong scouring requirements during the cleaning stage caused by the fixed structure of existing backplates; it overcomes the cleaning dead zones and gas waste caused by the unadjustable flow field vector, and realizes adaptive switching and efficient matching of flow fields in different process stages.

[0005] The present invention solves the above-mentioned technical problems through the following technical solution: The present invention includes a substrate, wherein an air inlet hole is formed on the upper surface of the substrate;

[0006] Multiple air diversion mechanisms are rotatably disposed on the lower surface of the substrate and distributed along the circumference of the substrate. The air diversion mechanism has two airflow channel structures, namely, exhaust holes and exhaust grooves.

[0007] A drive mechanism, disposed on the substrate, is used to drive multiple air diversion mechanisms to rotate synchronously, thereby switching different airflow channel structures to the working position.

[0008] Preferably, the gas splitting mechanism includes:

[0009] The flow divider is rotatably and internally mounted on the lower surface of the substrate;

[0010] At least two sets of exhaust holes are provided on the side wall of the diversion tube. Each set of exhaust holes is distributed at intervals along the circumference of the diversion tube, and each set of exhaust holes has a different aperture specification to provide different airflow injection patterns during the deposition stage.

[0011] Preferably, an exhaust groove is also provided on the side wall of the diverter cylinder, and the exhaust groove extends along the axial direction of the diverter cylinder to provide high-throughput airflow injection during the cleaning stage.

[0012] Preferably, both ends of the diverter are connected and fixed with external pipes, and each end of the two external pipes is equipped with a pneumatic rotary joint.

[0013] The substrate has a first gas supply pipe communicating with the air inlet; the substrate has a first annular inner hole, the first annular inner hole is connected to a second gas supply pipe, the upper side of the first annular inner hole is connected to a first gas supply channel, and the upper side of the first gas supply channel is equipped with a first gas connector.

[0014] The first gas pipeline and the second gas pipeline are respectively connected to gas rotary joints located on the inner and outer sides.

[0015] Preferably, multiple flow dividers are fixed inside the exhaust trough to change the injection direction of the cleaning gas. The multiple flow dividers are distributed along the axial direction of the flow divider cylinder, and the flow divider located in the middle is perpendicular to the surface of the flow divider cylinder. The angle of inclination of the flow dividers relative to the normal of the flow divider cylinder gradually increases as they extend towards both ends.

[0016] Preferably, both of the outer pipes are equipped with one-way valves, and the opening direction of both one-way valves is towards the inner cavity of the diverter.

[0017] Preferably, the lower surface of the substrate is provided with a mounting groove adapted to the diverter cylinder, and chamfered grooves are provided on both sides of the lower edge of the mounting groove, and an expandable and contractible sealing elastic bladder is provided in the chamfered groove;

[0018] The sealing elastic bladder is connected to an external air pressure control source and is used to expand during the deposition stage to seal the gap between the diversion tube and the mounting groove, and to contract during the cleaning stage to release space.

[0019] Preferably, the sealing elastic bladder includes a transverse portion parallel to the bottom of the substrate, and an arc-shaped portion connected to the transverse portion near the side of the diversion cylinder;

[0020] A rigid partition is provided in the middle of the transverse section, which divides the two sides of the transverse section into a first flexible partition and a second flexible partition.

[0021] The surface of the arc-shaped part near the flow divider has a notch.

[0022] Preferably, the drive mechanism includes:

[0023] Gears fixed to the plurality of the gas splitting mechanisms;

[0024] A rack that meshes with the gear;

[0025] Wire ropes connecting adjacent racks;

[0026] A linear actuator fixed to the substrate, wherein the telescopic end of the linear actuator is fixedly connected to one of the steel wire ropes via a connecting vertical rod;

[0027] When the linear actuator extends or retracts, it drives multiple racks to move synchronously via the wire rope, thereby driving multiple distributor cylinders to rotate synchronously.

[0028] Preferably, a tapered hole is provided in the middle of the lower surface of the substrate. The tapered hole is coaxially arranged with the air inlet and is interconnected with it. The tapered hole has a longitudinal cross-sectional structure that is narrow at the top and wide at the bottom, which is used to guide the incoming airflow to depressurize along the tapered surface and diffuse in all directions.

[0029] This invention also proposes a flow field control method utilizing the backplate of a PECVD chamber, comprising the following steps:

[0030] S1: The control drive mechanism drives multiple gas splitting mechanisms to rotate synchronously to the working position of the deposition stage, so that the exhaust port of the gas splitting mechanism is in working condition.

[0031] S2: Introduce deposition gas into the air inlet, and discharge the deposition gas through the exhaust port into the process chamber to form the airflow field required for the deposition process;

[0032] S3: After the deposition process is completed, stop the introduction of deposition gas and control the drive mechanism to drive multiple gas splitting mechanisms to rotate synchronously to the working position of the cleaning stage, so that the exhaust groove of the gas splitting mechanism is in working state.

[0033] S4: Introduce cleaning gas into the gas splitting mechanism, so that the cleaning gas is discharged into the process chamber through the exhaust port, forming the airflow field required for the cleaning process;

[0034] S5: During the cleaning process, the control drive mechanism drives multiple air diversion mechanisms to swing back and forth within a preset angle range to dynamically adjust the spray direction of the cleaning gas.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0036] 1. This invention integrates two airflow channel structures on the same backplate by setting a rotatable gas splitting mechanism. During the deposition stage, it switches to a micropore exhaust mode to achieve low-pressure laminar uniform jetting, ensuring consistent film thickness; during the cleaning stage, it switches to a wide-groove exhaust mode to generate a high-energy scouring airflow. This structural design allows the different flow field requirements of the deposition and cleaning processes to be accommodated on the same hardware, completely solving the technical problem that traditional fixed-hole structures cannot achieve both simultaneously.

[0037] 2. In cleaning mode, the exhaust duct is equipped with a diverter plate with an increasing tilt angle, which forcibly guides the originally vertically downward airflow into an outward-expanding fan-shaped jet. Combined with the reciprocating oscillation function of the diverter cylinder, highly reactive fluorine radicals can impact the chamber sidewalls, the back of the diffuser, and the dead corners of the support from multiple angles and phases, achieving comprehensive stripping of byproducts. Cleaning time is significantly shortened, cleaning gas consumption is reduced, and equipment maintenance downtime is effectively extended.

[0038] 3. In deposition mode, multiple sets of vent holes with different diameters are arranged in a ring array, allowing for the selection of the optimal vent diameter based on the process formulation. After pre-diffusing through conical orifices, the gas is evenly distributed to each distribution tube via radial first gas delivery channels, and then vertically ejected from a selected set of vent holes. The annular symmetrical gas distribution structure ensures a high degree of consistency in the radial airflow within the process chamber, enabling nanometer-level control of the film thickness uniformity on the substrate surface, significantly improving product yield.

[0039] 4. One-way valves are integrated into the external pipes at both ends of the distributor, and their opening direction is towards the inner cavity of the distributor, achieving physical isolation between the depositing gas and the cleaning gas. During the depositing stage, the depositing gas will not flow back into the cleaning pipeline, and during the cleaning stage, the highly corrosive nitrogen trifluoride will not flow back into the depositing gas path. The dynamic sealing design of the rotary joint, combined with the "in-only" characteristic of the one-way valve, effectively protects the upstream gas source system and extends the service life of precision components.

[0040] 5. Expandable and contractible sealing elastic bladders are installed on both sides of the mounting groove. During the deposition stage, the bladders inflate and expand, closely adhering to the surface of the distribution tube to shield non-working orifices, ensuring that gas is ejected only from the pre-set exhaust ports and maintaining laminar flow stability. During the cleaning stage, the bladders are evacuated and contracted, releasing the space below to expand the exhaust diffusion angle. The elastic bladders are made of perfluoroether rubber, maintaining excellent elasticity even in high-temperature and highly corrosive plasma environments, achieving a high degree of synergy between sealing protection and flow field optimization. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the existing backplate structure;

[0042] Figure 2 This is a three-dimensional structural diagram of the present invention from a top view.

[0043] Figure 3 This is a three-dimensional structural diagram from the bottom view during the cleaning stage of the present invention.

[0044] Figure 4 This is a three-dimensional structural diagram from the bottom view of the deposition stage of the present invention;

[0045] Figure 5 This is a schematic diagram of the structure of the multiple air diversion mechanisms and drive mechanisms of the present invention;

[0046] Figure 6 This is a three-dimensional structural schematic diagram of a single gas splitting mechanism of the present invention;

[0047] Figure 7 A cross-sectional three-dimensional structural diagram of a single gas splitting mechanism;

[0048] Figure 8 A cross-sectional view of a single air splitter along its axial direction;

[0049] Figure 9 A schematic cross-sectional view of a single gas splitting mechanism along its radial direction;

[0050] Figure 10 for Figure 9 Enlarged structural diagram at point A in the diagram;

[0051] Figure 11 This is a flowchart of the flow field control method of the present invention.

[0052] The numbers in the diagram represent:

[0053] 1-Baseboard; 21-Air inlet; 22-Conical hole; 23-First air supply pipe; 3-Air diversion mechanism; 31-Diverter cylinder; 32-Exhaust hole; 33-Exhaust groove; 34-Diverter plate; 35-External pipe; 36-Air rotary joint; 37-One-way valve; 41-First air connector; 42-First air supply channel; 43-First annular inner hole; 44-Second air supply pipe; 51-Rack; 52-Gear; 53-Wire rope; 54-Linear actuator; 55-Connecting vertical rod; 61-Second air connector; 62-Second annular inner hole; 63-Second air supply channel; 64-Third air supply channel; 65-First flexible partition; 66-Rigid partition; 67-Second flexible partition; 68-Arc-shaped part; 69-Notch groove. Detailed Implementation

[0054] The above-mentioned and other technical features and advantages of the present invention will be described in more detail below with reference to the accompanying drawings.

[0055] This embodiment provides a technical solution: a PECVD chamber backplate, such as... Figures 1-10 As shown, substrate 1 has an overall disk-shaped structure and is typically made of a metal material (such as aluminum alloy) with good thermal conductivity and corrosion resistance. The lower surface of substrate 1 extends downwards and protrudes from its central region, forming a raised portion. This raised portion not only enhances the mechanical strength of the central region but also provides the necessary thickness space for the opening of internal airflow channels. An air inlet 21 is provided at the center of the upper surface of substrate 1 (i.e., the geometric center position), and correspondingly, a tapered hole 22 is provided at the center of the lower surface of substrate 1.

[0056] The inlet 21 is sealed to an external deposition gas source via a flange or gas line connector, used to introduce the process gas required for film formation. Depending on process requirements, this deposition gas can be one or more of ammonia, nitrogen, or nitrous oxide. The inlet 21 and the tapered hole 22 are coaxially arranged and vertically connected inside the substrate 1. The tapered hole 22 adopts a longitudinal cross-section design that is narrower at the top and wider at the bottom. This geometry facilitates the smooth decompression and diffusion of the high-pressure gas flow entering from the inlet 21 along the tapered surface during downward flow, thereby reducing local turbulence effects and laying the foundation for subsequent uniform flow distribution.

[0057] On the outer periphery of the protrusion on the lower surface of the substrate 1, there are multiple air diversion mechanisms 3 for adjusting the airflow injection state. All multiple air diversion mechanisms 3 adopt an embedded installation method, that is, a matching mounting groove is processed at a preset position on the lower surface of the substrate 1, so that the main body of the air diversion mechanism 3 is embedded in the substrate 1.

[0058] Each gas splitting mechanism 3 is equipped with a rotating support structure (such as a bearing or a rotary seal), enabling it to rotate axially relative to the substrate 1, thereby achieving switching between different flow field modes. In terms of spatial arrangement, multiple gas splitting mechanisms 3 are distributed in a ring array at equal angles, with the central axis of the conical hole 22 as the center. This ring array design ensures that the process gas flowing out from the central conical hole 22 can enter each gas splitting mechanism 3 in a radially symmetrical manner, thus forming a highly symmetrical and uniform airflow field within the process cavity below the entire substrate, effectively guaranteeing the consistency of the thin film deposition thickness on the substrate surface.

[0059] The air diversion mechanism 3 includes a diversion cylinder 31 rotatably mounted in the mounting groove, and the rotation of the diversion cylinder 31 is achieved by a drive mechanism. It should be noted that most of the diversion cylinder 31 is located inside the substrate 1, and a portion of its lower side protrudes from the lower surface of the substrate 1. Specifically, both ends of the diversion cylinder 31 are connected and fixed with external pipes 35, and the two external pipes 35 are rotatably connected to the substrate 1 through bearings.

[0060] The air inlet 21 serves as the main inlet for the deposited gas, and it is fluidly connected to the outer pipe 35 inside each gas distribution mechanism 3 via the first gas supply pipe 23 located inside the substrate 1. Specifically, the first gas supply pipe 23 is radially or branched inside the substrate 1, precisely guiding the deposited gas from the central region to each gas distribution mechanism 3 arranged in a ring array. The deposited gas sequentially passes through the air inlet 21 and the first gas supply pipe 23 into the internal space of the outer pipe 35, and finally converges in the inner cavity of the distribution cylinder 31, forming a pressure chamber to be injected.

[0061] At least two sets of exhaust holes 32 with different functions are provided on the circumferential sidewall of the flow divider 31. In order to achieve precise flow regulation, multiple sets of exhaust holes 32 are distributed at intervals along the radial (i.e., circumferential) direction of the flow divider 31 to ensure that the position of each set of holes can be switched independently during rotation. Within each set, multiple exhaust holes 32 are linearly arranged along the axial (length) direction of the flow divider 31 to ensure the spray coverage of gas along the axial length.

[0062] Significantly, the vent holes 32 in different groups have different pore size specifications. For example, the first group of vent holes 32 can be designed with micropores for low-flow, high-precision thin film growth stages; the second group of vent holes 32 can be designed with larger pore sizes for rapid deposition stages. This pore size gradient allows a single hardware structure to cover a variety of complex process formulations.

[0063] Driven by the drive mechanism, the flow divider 31 can rotate precisely around its own axis. Through this rotation, the operator or control system can selectively switch a set of exhaust ports 32 corresponding to the process requirements to the bottom of the flow divider 31, i.e., vertically facing the process chamber. At this time, the selected set of exhaust ports 32 is aligned with the opening on the lower surface of the substrate 1, while the other sets of exhaust ports 32 are physically blocked by the inner wall of the substrate 1, thereby achieving directional switching of the air path.

[0064] Under pressure, the deposition gas is ejected through the downward-facing exhaust ports 32 and enters the process chamber of the PECVD machine. Through this mechanical aperture switching method, the present invention can flexibly adapt to different requirements in the PECVD process regarding deposition gas injection rate, pressure, and diffusion distribution, achieving instantaneous optimization of the flow field environment without replacing the backplate.

[0065] The outer pipe 35 on the outside of the gas splitting mechanism 3 is connected to an external cleaning gas source to transmit the cleaning gas into the gas splitting mechanism 3, and then splits it into the process chamber of the PECVD machine to clean the process chamber. The cleaning gas is nitrogen trifluoride. Specifically, a first annular inner hole 43 is formed inside the substrate 1. The first annular inner hole 43 is located outside the outer pipe 35. A first gas supply channel 42 is connected to the upper side of the first annular inner hole 43, and a first gas connector 41 is installed on the upper side of the first gas supply channel 42 to facilitate connection with the corresponding gas pipe. The first annular inner hole 43 and the outer pipe 35 on the outside of the gas splitting mechanism 3 are connected through a second gas supply pipe 44.

[0066] An exhaust groove 33 is provided on the flow divider 31, and the exhaust groove 33 is arranged along the axial direction of the flow divider 31 to form a long strip-shaped exhaust window to meet the high-throughput gas requirements of the cleaning stage. In order to disperse the cleaning gas as much as possible, multiple flow dividers 34 are fixed in the exhaust groove 33. Taking the axial center point of the flow divider 31 as the reference point, the flow divider 34 located in the middle is basically perpendicular to the surface of the cylinder, while the angle of inclination of the flow divider 34 relative to the normal of the flow divider 31 gradually increases as it extends towards both ends (i.e., further away from the reference point). This gradient inclination design forms a "fan-shaped expansion" guiding system, which allows the cleaning gas to be forced to change its vector direction when it is discharged through the exhaust groove 33, and diffuse to the periphery and corner areas of the process chamber to achieve all-round flushing.

[0067] To significantly enhance the control of the airflow vector by the manifold 34, this embodiment locally strengthens the structure of the manifold 31. Specifically, in the region where the exhaust groove 33 is formed, the wall thickness of the manifold 31 is increased compared to other regions (such as the region where the exhaust hole 32 is formed). By increasing the sidewall thickness, the radial depth of the exhaust groove 33 is extended, thereby providing a longer physical guide surface for the manifold 34.

[0068] A longer flow path effectively constrains the airflow trajectory before it leaves the distributor tube 31, reducing airflow dispersion and ensuring that high-speed fluorine radicals are precisely and powerfully directed towards the dead corners of the PECVD machine's process chamber and the outer edge of the diffuser. This coupled design of thickness and flow guidance effect (such as...) Figure 7 As shown in the figure, without increasing the overall size, it greatly improves cleaning efficiency and shortens maintenance downtime.

[0069] To ensure process purity and prevent cross-contamination between the chemically dissimilar deposit gases and cleaning gases within the pipeline, this device integrates one-way valves 37 inside both external connecting pipes 35. Specifically, the one-way valve 37 located in the inner external connecting pipe 35 (connected to the deposit gas path) opens towards the inner cavity of the distribution cylinder 31, allowing only deposit gas to enter the cylinder; similarly, the one-way valve 37 located in the outer external connecting pipe 35 (connected to the cleaning gas path) also allows only the cleaning gas to flow unidirectionally into the cylinder. This symmetrical one-way blocking design achieves the physical characteristic of "gas only entering, not exiting," effectively preventing deposit gas from reversing into the cleaning pipeline during the deposit stage, or highly corrosive nitrogen trifluoride gas from flowing back into the deposit gas path during the cleaning stage. This protects the safety of the upstream gas source system and extends the service life of precision gas path components.

[0070] Considering that the manifold 31 needs to rotate frequently under the action of the drive mechanism to switch process modes, this device adopts a dynamic sealing design at the outer end of the outer pipe 35. Specifically, each outer end of the outer pipe 35 is precisely fitted with a gas rotary joint 36. The first gas supply pipe 23 and the second gas supply pipe 44 extend to both sides of the manifold 31 respectively and are firmly connected to the static end of their respective gas rotary joints 36. The gas rotary joint 36 serves as a transition hub between the static pipeline and the dynamic rotating component. It is equipped with a sealed bearing and a high-temperature resistant sealing ring, which can maintain airtightness in a high vacuum environment while allowing the outer pipe 35 to rotate freely with the manifold 31 relative to the substrate 1.

[0071] Before the deposition process is executed, the system sends a command to the drive mechanism, which drives the flow dividers 31 in each gas flow divider 3 to rotate synchronously. Through precise angle control, a set of pre-set exhaust holes 32 that conform to the current thin film growth formula are rotated to the lowest position and aligned with the PECVD machine process chamber below.

[0072] Subsequently, the deposition gas supply source is activated, and the deposition gas is input through the inlet 21. As the deposition gas passes through the tapered orifice 22, its gradually expanding geometry allows for initial pressure reduction and flow stabilization, after which it is diverted into the first gas delivery pipe 23. The deposition gas ultimately collects within the diversion cylinder 31 of the multiple gas diversion mechanisms 3 and is ejected from a set of exhaust ports 32 facing the process chamber. Because the multiple gas diversion mechanisms 3 are arranged in a ring array, and each set of exhaust ports 32 is designed for flow equalization, the deposition gas can enter the process chamber in a highly uniform laminar flow state. Under the excitation of plasma energy, the gas undergoes chemical decomposition to generate reactive groups. These groups are adsorbed, migrated, and ultimately recombine on the substrate surface to form a uniformly thick and stable solid film or powder.

[0073] After the deposition process is completed, in order to remove the residue in the chamber, the drive mechanism is restarted, causing the diverter 31 to rotate at a preset angle, so that the exhaust groove 33, which has a large area opening, switches to the working position facing the process chamber. At this time, the original deposition gas path is locked by a one-way valve.

[0074] The cleaning gas supply source begins supplying gas, which sequentially enters the first annular inner hole 43 through the first gas connector 41 and the first gas delivery channel 42 for pressure equalization, and then flows into the distribution cylinder 31 through the second gas delivery pipe 44. When the high-pressure cleaning gas is discharged through the exhaust groove 33, multiple distribution plates 34 installed in the groove play a crucial guiding role. Utilizing the increasing tilt angle of the distribution plates 34 from the center to the edge, the originally vertically downward airflow is forcibly guided into an outwardly expanding oblique airflow. This controlled flow field direction not only covers the central area of ​​the substrate but also generates a strong centrifugal scouring effect, allowing highly reactive fluorine radicals to directly act on the sidewalls, edges, and dead-angle areas on the back of the diffuser of the process chamber. Through the dual action of physical bombardment and chemical etching, byproducts in the contaminated areas are efficiently removed, significantly improving the cleanliness of the chamber.

[0075] During the cleaning phase, the drive mechanism does not only rotate the diverter cylinder 31 to a fixed position, but can also drive the diverter cylinder 31 to perform step-by-step or continuous reciprocating oscillations within a certain angle range according to the preset cleaning program or real-time feedback. By fine-tuning the angle position of the diverter cylinder 31, the spatial orientation of the exhaust groove 33 and its internal flow divider plate 34 relative to the process chamber can be directly changed.

[0076] This dynamic adjustment mechanism makes the injection angle of the cleaning gas flow no longer fixed. For example, by driving the splitter tube 31 to rotate slightly, the cleaning gas can be changed from the initial lateral diffusion state to a "fixed-point scanning" state targeting specific dead-angle areas. This adjustable angle ensures that active particles such as fluorine radicals can impact the chamber walls and diffuser edges at multiple angles and in multiple phases, thereby more effectively destroying and stripping by-product deposits attached at different angles.

[0077] Through the dynamic switching between the two stages described above, this invention achieves complete decoupling of flow field characteristics within the same hardware system. The deposition stage utilizes the exhaust port 32 to achieve low-pressure, uniform laminar flow control, ensuring product yield. The cleaning stage utilizes the exhaust channel 33 and the flow divider 34 to achieve high-energy, wide-coverage swirling scouring, ensuring production efficiency. This design, which alters the exhaust geometry through a rotating mechanism, significantly optimizes gas utilization, reduces cleaning gas consumption, and effectively extends the continuous operating time of the machine.

[0078] The drive mechanism includes gears 52 fixed to the outer pipes 35 of multiple air splitting mechanisms 3, and racks 51 meshing with the upper side of the gears 52. Adjacent racks 51 are connected by steel wire ropes 53. It should be noted that mounting grooves are provided at corresponding positions on the base plate 1. Both racks 51 and gears 52 are located within these mounting grooves, and racks 51 are laterally slidably mounted within them. Connecting holes are provided between adjacent mounting grooves, and steel wire ropes 53 pass through these connecting holes and remain taut. Therefore, multiple racks 51 move with the same displacement. A linear actuator 54 (such as an electric push rod or cylinder) is fixed to the upper surface of the base plate 1. A connecting vertical rod 55 is fixed to the telescopic end of the linear actuator 54, and a groove connecting to the corresponding connecting hole is provided on the upper surface of the base plate 1. The connecting vertical rod 55 is fixedly connected to the corresponding steel wire rope 53. When the linear actuator 54 extends or retracts, multiple steel wire ropes 53 drive multiple racks 51 to move synchronously, thereby driving multiple distributors 31 to rotate synchronously by the same angle.

[0079] To ensure reliable airtightness of the vent 32 and vent groove 33 when idle and to prevent gas leakage from non-working areas, sealing elastic bladders are provided on both sides of the diverter 31. Specifically, chamfered grooves are provided on both sides of the lower edge of the mounting groove on the substrate 1, and the sealing elastic bladders are adapted to be installed in the chamfered grooves.

[0080] The sealing elastic bladder has an overall elongated triangular structure. Its structure includes a transverse portion parallel to the bottom of the substrate 1, and an arc-shaped portion 68 connected to the transverse portion near the diverter cylinder 31. A rigid partition 66 with a certain degree of rigidity is provided in the middle of the transverse portion. Due to the physical separation effect of the rigid partition 66, a first flexible partition 65 and a second flexible partition 67 are formed on both sides of the transverse portion, respectively. Furthermore, a notch 69 is formed on the surface of the arc-shaped portion 68 near the diverter cylinder 31. This notch 69 serves as a stress guide, allowing the arc-shaped portion 68 to fold in a controlled manner along the notch 69 when the sealing elastic bladder is compressed and contracted.

[0081] A second annular inner hole 62 is formed inside the substrate 1, serving as a pressure buffer and distribution center. Two second air supply channels 63 are connected to the upper side of the second annular inner hole 62, with second air connectors 61 correspondingly mounted on their tops. These two second air connectors 61 are connected to an air supply source and an air pump respectively via external pipelines. Third air supply channels 64 are symmetrically formed on both outer sides of the mounting groove, connecting the inner cavity of the sealing elastic bladder to the second annular inner hole 62, thereby achieving precise control over the expansion and contraction of the sealing elastic bladder.

[0082] During the deposition stage: Compressed air is injected into the sealing elastic bladder via an external air source through the second air connector 61, causing it to expand under pressure. The expanded sealing elastic bladder fills the gap at the edge of the mounting groove, achieving a tight seal between the diverter cylinder 31 and the mounting groove. At this time, the sidewall of the sealing elastic bladder is tightly attached to the cylinder surface, completely covering and sealing the unused exhaust holes 32 (non-working angle group) and exhaust groove 33, leaving only the exhaust holes 32 in the working position (the downward-facing group) exposed to the outside. This "compression" seal ensures that the deposited gas is discharged only from the predetermined holes, maintaining the purity and pressure stability of the laminar flow field.

[0083] To ensure reliability under the high temperature and highly corrosive plasma environment of PECVD, the sealing elastic bladder described in this invention is preferably made of perfluoroether rubber. This material maintains excellent physical elasticity even at high temperatures of 250°C-350°C and exhibits excellent chemical inertness to fluorine free radicals generated by nitrogen trifluoride plasma.

[0084] During the cleaning stage: Air is extracted from the sealed elastic bladder through the second air connector 61 using an air pump, creating an internal negative pressure. Under the mechanical action of the negative pressure drive and the rotation of the diverter 31, the sealed elastic bladder undergoes a predetermined contraction deformation: the lateral part flips upward to avoid the first flexible spacer 65 as the support point; the arc-shaped part 68 flexibly folds inward with the notch 69 as the base point; and the second flexible spacer 67 is directly squeezed by the outer wall of the rotating diverter 31.

[0085] The unique feature of this design is that, during the cleaning phase, the retracted sealing elastic bladder not only maintains a basic seal at the edge of the diverter 31 through the local compression of the second flexible spacer 67 and the arc-shaped portion 68, preventing cleaning gas from leaking into the substrate along the sidewall, but more importantly, the retracting and flipping action of the sealing elastic bladder releases the physical space below the mounting groove, thereby expanding the effective diffusion angle when the exhaust groove 33 exhausts gas. This, combined with the guiding effect of the diverter plate 34, further enhances the ability of cleaning gas to cover the dead corners at the edge of the process chamber, achieving a high degree of synergy between sealing protection and flow field optimization.

[0086] The above description is merely a preferred embodiment of the present invention and is illustrative rather than restrictive. Those skilled in the art will understand that many changes, modifications, and even equivalents can be made within the spirit and scope defined by the claims of the present invention, all of which will fall within the protection scope of the present invention.

Claims

1. A PECVD chamber backplate, characterized in that, include: A substrate (1) has an air inlet (21) on its upper surface; multiple air diversion mechanisms (3) are rotatably disposed on the lower surface of the substrate (1) and distributed along the circumference of the substrate (1). The air diversion mechanism (3) has two airflow channel structures. The air inlet (21) is connected to the multiple air diversion mechanisms (3) to realize gas transmission; a driving mechanism is disposed on the substrate (1) and is used to drive the multiple air diversion mechanisms (3) to rotate synchronously to switch different airflow channel structures to the working position. The gas splitting mechanism (3) includes: a splitting cylinder (31), which is rotatably and internally mounted on the lower surface of the substrate (1); At least two sets of exhaust holes (32) are provided on the side wall of the diversion tube (31). Each set of exhaust holes (32) is distributed circumferentially along the diversion tube (31). Each set of exhaust holes (32) has a different aperture specification to provide different airflow injection patterns during the deposition stage. The side wall of the diverter (31) is also provided with an exhaust groove (33), which extends along the axial direction of the diverter (31) and is used to provide high-throughput airflow injection during the cleaning stage. Both ends of the diverter tube (31) are connected and fixed with external pipes (35), and the ends of the two external pipes (35) are equipped with air rotary joints (36); the interior of the base plate (1) is provided with a first air supply pipe (23) connected to the air inlet (21); the interior of the base plate (1) is provided with a first annular inner hole (43), the first annular inner hole (43) is connected with a second air supply pipe (44), the upper side of the first annular inner hole (43) is connected with a first air supply channel (42), and the upper side of the first air supply channel (42) is equipped with a first air connector (41); the first air supply pipe (23) and the second air supply pipe (44) are respectively connected to the air rotary joints (36) located on the inner and outer sides.

2. The PECVD chamber backplate as described in claim 1, characterized in that, Multiple flow dividers (34) are fixed inside the exhaust trough (33) to change the injection direction of the cleaning gas. The multiple flow dividers (34) are distributed along the axial direction of the flow divider (31), and the flow divider (34) located in the middle is perpendicular to the surface of the flow divider (31). The angle of inclination of the flow dividers (34) relative to the normal of the flow divider (31) gradually increases as they extend towards both ends.

3. The PECVD chamber backplate as described in claim 1, characterized in that, Both of the external pipes (35) are equipped with one-way valves (37), and the opening direction of both one-way valves (37) is towards the inner cavity of the diverter (31).

4. The PECVD chamber backplate as described in claim 1, characterized in that, The lower surface of the substrate (1) is provided with an installation groove adapted to the diversion cylinder (31). Chamfered grooves are provided on both sides of the lower edge of the installation groove. An expandable and contractible sealing elastic bladder is provided in the chamfered groove. The sealing elastic bladder is connected to an external air pressure control source and is used to expand during the deposition stage to seal the gap between the diversion cylinder (31) and the installation groove, and to contract during the cleaning stage to release space.

5. The PECVD chamber backplate as described in claim 4, characterized in that, The sealing elastic bladder includes a transverse portion parallel to the bottom of the substrate (1) and an arc-shaped portion (68) connected to the transverse portion near the side of the diverter cylinder (31); a rigid partition (66) is provided in the middle of the transverse portion, which divides the two sides of the transverse portion into a first flexible partition (65) and a second flexible partition (67); a notch (69) is provided on the surface of the arc-shaped portion (68) near the side of the diverter cylinder (31).

6. The PECVD chamber backplate as described in claim 1, characterized in that, The drive mechanism includes: Gears (52) fixed on multiple air splitting mechanisms (3); A rack (51) meshes with the gear (52); Wire rope (53) connecting adjacent racks (51); A linear actuator (54) is fixed on the substrate (1), and the telescopic end of the linear actuator (54) is fixedly connected to one of the steel wire ropes (53) through a connecting rod (55). When the linear actuator (54) extends or retracts, it drives multiple racks (51) to move synchronously through the wire rope (53), thereby driving multiple air diversion mechanisms (3) to rotate synchronously.

7. The PECVD chamber backplate as described in claim 1, characterized in that, A tapered hole (22) is provided in the middle of the lower surface of the substrate (1). The tapered hole (22) is coaxially arranged with the air inlet (21) and is interconnected. The tapered hole (22) has a longitudinal cross-section structure that is narrow at the top and wide at the bottom, which is used to guide the incoming airflow to depressurize along the tapered surface and diffuse to the surroundings.

8. A method for flow field control using the PECVD chamber backplate as described in any one of claims 1-7, characterized in that, Includes the following steps: S1: The control drive mechanism drives multiple gas splitting mechanisms to rotate synchronously to the working position of the deposition stage, so that the exhaust port of the gas splitting mechanism is in working condition. S2: Introduce deposition gas into the air inlet, and discharge the deposition gas through the exhaust port into the process chamber to form the airflow field required for the deposition process; S3: After the deposition process is completed, stop the introduction of deposition gas and control the drive mechanism to drive multiple gas splitting mechanisms to rotate synchronously to the working position of the cleaning stage, so that the exhaust groove of the gas splitting mechanism is in working state. S4: Introduce cleaning gas into the gas splitting mechanism, so that the cleaning gas is discharged into the process chamber through the exhaust port, forming the airflow field required for the cleaning process; S5: During the cleaning process, the control drive mechanism drives multiple air diversion mechanisms to swing back and forth within a preset angle range to dynamically adjust the spray direction of the cleaning gas.

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