Chamber top cover and CVD reaction apparatus

Abstract

A chamber top cover and a CVD reaction apparatus, relating to the technical field of semiconductor equipment. The chamber top cover is disposed on a reaction chamber of the CVD reaction apparatus, and comprises: a restriction ring, which is located above the reaction chamber, and extends along an axial direction of the reaction chamber; a gas supply portion, which is disposed at a top end of the restriction ring, and is used to inject a process gas into the reaction chamber; a top cover side wall, which surrounds an outer periphery of the restriction ring; a top cover plate, which is fixedly disposed at a top end of the top cover side wall, and surrounds an outer periphery of the gas supply portion, the restriction ring, the top cover side wall and the top cover plate together enclosing a top cover buffer chamber, through which a purge gas is injected into the reaction chamber; and a flow blocking plate, which is disposed at a bottom of the top cover buffer chamber, and surrounds an outer periphery of the restriction ring, a gap being provided between the flow blocking plate and the top cover side wall and restriction ring. The present invention can prevent alloy elements from precipitating from the chamber top cover, reduce corrosion of the chamber top cover, and reduce attachment of reaction by-products to the chamber top cover.

Description

A chamber top cover and CVD reaction device Technical Field

[0001] This invention relates to the field of semiconductor equipment technology, and in particular to a chamber top cover and a CVD reaction apparatus. Background Technology

[0002] Existing CVD (Chemical Vapor Deposition) reactors for epitaxial growth of single-crystal thin films (such as silicon carbide and gallium nitride films) have a reaction chamber with a top cover. A gas spray head is mounted on the top cover and injects process gases for film growth into the reaction chamber. A tray for supporting the substrate is located at the bottom of the reaction chamber, and a heater heats the substrate to meet the temperature conditions for film growth.

[0003] During silicon carbide epitaxial growth, the temperature inside the chamber is relatively high (typically around 1600℃). The chamber top cover is usually made of stainless steel, and chromium in stainless steel easily precipitates and deposits on the substrate at high temperatures, causing metal contamination. Furthermore, process gases or cleaning gases are often highly corrosive, corroding the chamber and leading to gas leaks. During the process, in addition to epitaxial film formation on the substrate, process gases also deposit on the surface of the chamber top cover or the chamber walls, forming reaction byproducts. When these byproduct particles fall onto the substrate, they cause surface defects. In such cases, the chamber top cover needs to be frequently opened for cleaning, a time-consuming, cumbersome process requiring specialized personnel, resulting in high maintenance costs and low production efficiency for the CVD reactor.

[0004] Disclosure of the invention

[0005] The purpose of this invention is to provide a chamber top cover and a CVD reaction apparatus that can reduce the temperature of the chamber top cover, prevent the precipitation of alloying elements from the top cover causing metal contamination, and significantly reduce the deposition of reaction byproducts on the top cover. Simultaneously, it can also reduce the risk of process gas leakage due to corrosion and deformation of the top cover by process gases, ensuring the safety of substrate processing.

[0006] To achieve the above objectives, the present invention provides a cavity top cover, which is disposed on the reaction chamber of a CVD reaction apparatus, comprising:

[0007] A confinement ring is located above the reaction chamber and extends along the axial direction of the reaction chamber;

[0008] A gas supply unit, which is located at the top of the limiting ring, is used to inject process gas into the reaction chamber;

[0009] a top cover side wall surrounding the outer periphery of the limiting ring;

[0010] a top cover cover plate fixedly arranged at the top end of the top cover side wall and surrounding the outer periphery of the gas supply part; the limiting ring, the top cover side wall and the top cover cover plate together form a top cover buffer cavity; the top cover buffer cavity is used for injecting purge gas into the reaction cavity at least;

[0011] a baffle plate arranged at the bottom of the top cover buffer cavity and surrounding the outer periphery of the limiting ring; the baffle plate has a gap with the top cover side wall and the limiting ring.

[0012] Optionally, the baffle plate has a first gap with the top cover side wall; the baffle plate has a second gap with the limiting ring, and the first gap is larger than the second gap.

[0013] Optionally, the top of the limiting ring has a flow uniformizing plate extending radially outward; the top or the inside of the flow uniformizing plate is provided with a flow uniformizing groove; the flow uniformizing groove is in gas communication with an external purge gas source and the top cover buffer cavity.

[0014] Optionally, the flow uniformizing plate is arranged integrally with the limiting ring.

[0015] Optionally, the cavity top cover further comprises a connecting rod for hanging the baffle plate on the flow uniformizing plate.

[0016] Optionally, the top cover cover plate is provided with a first cooling part; the limiting ring is provided with a second cooling part; the distance between the second cooling part and the inner wall of the limiting ring is smaller than the distance between the second cooling part and the outer wall of the limiting ring.

[0017] Optionally, the cavity top cover further comprises a protective cover configured to cover the inner wall and the bottom surface of the limiting ring.

[0018] Optionally, the bottom of the protective cover is hung on the bottom surface of the limiting ring.

[0019] Optionally, the protective cover has a gap with the limiting ring.

[0020] Optionally, the bottom surface of the gas supply part is provided with a partition plate having a plurality of through holes; the outer edge of the partition plate is overlapped on the top of the protective cover.

[0021] Optionally, along the direction from top to bottom, the inner diameter of the limiting ring gradually increases.

[0022] The application further provides a CVD reaction device having a reaction cavity, wherein the reaction cavity is provided with the cavity top cover as described in the application; the inner diameter of the top cover side wall is not less than the inner diameter of the reaction cavity side wall at the joint thereof.

[0023] The bottom of the reaction cavity is provided with a rotating cylinder capable of rotating around its central axis.

[0024] The top of the rotating cylinder is provided with a tray for carrying a substrate; the tray is arranged opposite to the gas supply part.

[0025] Optionally, the reaction cavity is further provided with an upper bushing and a lower bushing; the upper bushing is located above the lower bushing and is arranged around the inner sidewall of the reaction cavity; the lower bushing is arranged around the inner sidewall between the rotating cylinder and the reaction cavity.

[0026] Optionally, the CVD reaction device further comprises a reflecting ring located between the limiting ring and the upper bushing; the inner diameter of the reflecting ring is smaller than the inner diameter of the upper bushing.

[0027] Optionally, along the direction from top to bottom, the inner diameter of the reflecting ring gradually decreases, and the process gas flowing out of the top cover buffer cavity is guided by the inner wall of the reflecting ring.

[0028] Optionally, the CVD reaction device further comprises a mounting ring arranged around the outer periphery of the upper bushing and the reflecting ring and coupled to the inner sidewall of the reaction cavity.

[0029] Optionally, the CVD reaction device further comprises a side heater and a lower heater; the side heater is arranged between the upper bushing and the inner sidewall of the reaction cavity and is used for heating the process gas in the reaction cavity; the lower heater is arranged in the rotating cylinder and is used for heating the substrate.

[0030] Optionally, the CVD reaction device further comprises an upper heat insulation cylinder and a lower heat insulation cylinder; the upper heat insulation cylinder is located above the lower heat insulation cylinder and is arranged around the inner sidewall between the side heater and the reaction cavity; the lower heat insulation cylinder is arranged around the inner sidewall between the lower bushing and the reaction cavity.

[0031] Optionally, the bottom of the top cover sidewall is connected to the top of the reaction cavity sidewall; a sealing ring is arranged between the top cover sidewall and the reaction cavity sidewall.

[0032] Optionally, the reaction cavity is further provided with a heat absorption cylinder located above the tray and extending along the axial direction of the reaction cavity; the heat absorption rate of the heat absorption cylinder is greater than the heat absorption rate of the process gas.

[0033] Compared with the prior art, the present application has the following advantages:

[0034] 1) The chamber top cover of the present application has a top cover buffer cavity, under the pressure of the purge gas in the top cover buffer cavity, the corrosive process gas or cleaning gas is not easy to flow into the top cover buffer cavity, reducing the risk of process gas leakage caused by the corrosion deformation of the top cover cover plate and the top cover side wall, ensuring the safety of substrate processing.

[0035] The purge gas can also quickly carry away the heat in the top cover buffer cavity, so the temperature of the inner wall of the top cover buffer cavity is lower, which can prevent alloy elements from being precipitated and causing metal contamination to the substrate, and can also prevent process gas from being deposited on the inner wall of the top cover buffer cavity, avoiding particles from the deposit entering the reaction chamber to cause particle contamination to the substrate. The present application improves the utilization rate of process gas, greatly reduces the frequency of maintenance of the chamber top cover and the reaction chamber, reduces the cost of substrate processing and improves the production efficiency.

[0036] The flow resistance of the process gas entering the top cover buffer cavity is increased by the flow resistance plate, which can effectively reduce the flow of the process gas into the top cover buffer cavity even when the flow rate of the process gas is fast. The flow resistance plate can also block the heat in the reaction chamber from radiating into the top cover buffer cavity, which helps to reduce the temperature in the top cover buffer cavity. The flow resistance plate also prolongs the residence time of the purge gas in the top cover buffer cavity and improves the uniformity of the distribution of the purge gas in the top cover buffer cavity.

[0037] 2) The first gap between the flow resistance plate and the top cover side wall is larger than the second gap between the flow resistance plate and the limiting ring, more purge gas is easy to flow from the first gap to the outside of the reflection ring and the mounting ring, flow through the upper surface of the reflection ring and the mounting ring, and then flow into the reaction chamber from the inside of the reflection ring and the mounting ring. Since the purge gas can flow through the entire upper surface of the reflection ring and the entire upper surface of the mounting ring, the deposition of by-products on the upper surface of the reflection ring and the upper surface of the mounting ring is greatly reduced.

[0038] 3) The flow uniformity plate of the present application is located in the top cover buffer cavity and is far away from the reaction chamber, so that the flow uniformity plate has a lower temperature, effectively avoiding deformation and warping of the flow uniformity plate caused by long-term exposure to high temperature environment. The present application connects the flow resistance plate to the flow uniformity plate through a connecting rod, greatly reducing the heat transferred from the flow resistance plate to the flow uniformity plate. The top surface of the flow uniformity plate contacts the bottom surface of the top cover cover plate, which can quickly carry away the heat of the flow uniformity plate while cooling the top cover cover plate through the first cooling part inside the top cover cover plate. Further, the flow uniformity plate and the limiting ring can be integrated to improve the heat transfer between the flow uniformity plate and the limiting ring. The heat of the flow uniformity plate can also be quickly carried away while cooling the limiting ring through the second cooling part inside the limiting ring.

[0039] 4) The second cooling part is closer to the inner wall of the confinement ring than to the outer wall of the confinement ring, and has a better cooling effect on the inner wall of the confinement ring. Through heat transfer between the process gas and the inner wall of the confinement ring, the process gas in the gas inlet area (the space surrounded by the inner wall of the confinement ring) cannot reach the required temperature for the reaction, preventing the process gas from reacting prematurely in the gas inlet area.

[0040] 5) The protective cover of the present application covers the inner wall and the bottom surface of the confinement ring, which can isolate the heat radiated from the reaction chamber to the confinement ring, and also prevent the reaction byproducts from adhering to the confinement ring. The bottom of the protective cover is hung on the bottom surface of the confinement ring, which is easy to install and remove. The protective cover has a thermal deformation accommodation gap between the protective cover and the confinement ring, which can avoid the protective cover being broken by the thermal expansion of the confinement ring.

[0041] 6) The present application is provided with a baffle plate on the bottom surface of the gas supply part, which can isolate the heat radiated from the reaction chamber to the gas supply part, and also prevent the reaction byproducts from adhering to the gas supply part.

[0042] 7) In the present application, the inner diameter of the top cover side wall is not less than the inner diameter of the reaction chamber side wall at the connection between the two, which is separated from the gas inlet area by the top cover buffer cavity filled with purge gas, so that the sealing ring between the top cover side wall and the reaction chamber side wall can be away from the heat source, effectively prolonging the service life of the sealing ring and reducing the risk of process gas leakage caused by the failure of the sealing ring.

[0043] 8) After the purge gas flows out of the top cover buffer cavity and enters the reaction chamber, it flows downward along the inner side wall of the upper sleeve under the pressure of the process gas, without affecting the flow direction and distribution of the process gas, avoiding interference with the process gas. The smooth transition of the gas flow field in the entire reaction chamber is conducive to maintaining the growth conditions of the substrate and ensuring the controllability of the process in the reaction chamber.

[0044] The purge gas can fully diffuse into the gaps between the choke plate, the reflection ring, the mounting ring, the top of the upper sleeve and other components, avoiding the formation of uncontrollable dead zones in the gas flow field at these gaps, preventing the residual process gas of the previous process from remaining at these gaps, and causing the characteristics of the film grown on the substrate surface to not meet the requirements. By purging the gas, the process gas of the current process can also be prevented from stagnating in the above-mentioned gaps, ensuring that the volume fraction of each component of the process gas reaching the substrate surface meets the process requirements, and improving the yield of substrate processing.

[0045] 9) The reflection ring reflects the heat from the reaction chamber downward, further reducing the temperature in the top cover buffer cavity and the gas inlet area. From top to bottom, the inner diameter of the reflection ring gradually decreases, which helps to guide the purge gas flowing out of the top cover buffer cavity downward to the inner side wall of the upper sleeve.

[0046] 10) The temperature of the gas near the side heater is high, and the gas is easy to flow upwards; the temperature of the gas near the center of the reaction cavity is low, and the gas is easy to flow downwards, thus a gas vortex is easy to be generated above the substrate. In the present application, the radial temperature gradient inside the reaction cavity is reduced by the heat absorption cylinder, the generation of the vortex is avoided, the growth condition of the substrate is more stable, and thus the thickness and the uniformity of the doping of the film grown on the whole substrate are improved. The inner diameter of the heat absorption cylinder is larger than the diameter of the substrate, and the possible particle contaminants on the heat absorption cylinder can be avoided from falling onto the surface of the substrate, and the quality of the substrate is further improved.

[0047] BRIEF DESCRIPTION OF DRAWINGS

[0048] In order to more clearly illustrate the technical solutions of the present application, the drawings required to be used in the description will be briefly introduced as follows. Obviously, the drawings in the following description are one embodiment of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings:

[0049] Fig. 1 is a structural schematic diagram of a CVD reaction device in an embodiment of the present application.

[0050] Fig. 2 is a structural schematic diagram of a cavity top cover in an embodiment of the present application.

[0051] Best mode for carrying out the present application

[0052] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings of the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative effort belong to the scope of protection of the present application.

[0053] It should be understood that, when used in the specification and the appended claims, the term "comprising" indicates the existence of the described features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0054] It should also be understood that the terms used in the present application specification are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the present application specification and the appended claims, unless otherwise clearly indicated by the context, the singular forms "a", "an" and "the" are intended to include the plural forms as well.

[0055] It should also be further understood that the term "and / or" as used in the specification and in the claims, means any one of the associated listed items, or a combination of any of the associated listed items, and includes all possible combinations thereof.

[0056] As used in the specification and in the claims, the term "if' can be interpreted as meaning "when" or "once" or "in response to a determination" or "in response to detecting" depending on the context. In addition, in the description of the application, the terms "first", "second", "third", etc. are used only to distinguish descriptions, and cannot be understood as indicating or implying relative importance.

[0057] The embodiment provides a cavity top cover 10, as shown in FIG. 1, which is arranged on a reaction cavity 20 of a CVD reaction device 1 and covers the reaction cavity 20. The CVD reaction device 1 is used for epitaxial growth of a silicon carbide film on a substrate, and the temperature in the reaction cavity 20 during film growth is generally about 1600°C. As shown in FIG. 1, the reaction cavity 20 includes a reaction cavity side wall 201 and a bottom plate 202, and a gas-tight internal processing space is formed by the cavity top cover 10, the reaction cavity side wall 201 and the bottom plate 202. Although the reaction cavity 20 shown is cylindrical, it can also be other shapes, such as square, hexagonal, octagonal or any other appropriate shape.

[0058] The cavity top cover 10 is generally made of a metal material (for example, stainless steel), as shown in FIGS. 1 and 2, and includes a top cover side wall 101, a top cover cover plate 102, a limiting ring 103, a gas supply part 104 and a flow resistance plate 106.

[0059] As shown in FIGS. 1 and 2, the top cover side wall 101 is sealingly connected to the reaction cavity side wall 201, and the top cover cover plate 102 is fixedly arranged at the top end of the top cover side wall 101, and a first cooling part 121 is arranged in the top cover cover plate 102. In the embodiment, the top cover side wall 101 and the top cover cover plate 102 are integrally formed, which helps to improve the heat conduction between the top cover cover plate 102 and the top cover side wall 101, and the heat of the top cover side wall 101 can also be quickly conducted away when the top cover cover plate 102 is cooled by the first cooling part 121. The top cover cover plate 102 and the top cover side wall 101 are prevented from precipitating alloy elements (for example, chromium) under the heat radiation of the reaction cavity 20, which causes metal contamination to the substrate in the reaction cavity 20. In other embodiments, the top cover side wall 101 and the top cover cover plate 102 can also be a split structure.

[0060] As shown in FIG. 1 and FIG. 2, the limiting ring 103 is located between the top cover 102 and the reaction cavity 20, and extends along the axial direction of the reaction cavity 20. The gas supply part 104 is arranged at the top end of the limiting ring 103, and the top cover 102 surrounds the outer periphery of the gas supply part 104. The process gas for growing the thin film is injected into the reaction cavity 20 through the gas supply part 104. In the embodiment, the process gas can be ethylene (C2H4), propane (C3H8), trichlorosilane (SiHCL3), silane (SiH4), hydrogen (H2), nitrogen (N2), ammonia (NH3), etc.

[0061] The space surrounded by the inner wall of the limiting ring 103 serves as the gas inlet area 10a of the CVD reaction device 1, and the gas inlet area 10a and the inside of the reaction cavity 20 are in communication with each other. The inner diameter of the limiting ring 103 gradually increases along the direction from top to bottom, which is conducive to guiding the process gas to the edge area of the reaction cavity 20 and making the process gas uniformly distributed in the reaction cavity 20.

[0062] As shown in FIG. 1 and FIG. 2, the second cooling part 122 is arranged in the limiting ring 103. In the embodiment, the distance between the second cooling part 122 and the inner wall of the limiting ring is smaller than the distance between the second cooling part 122 and the outer wall of the limiting ring. The second cooling part 122 has a better cooling effect on the inner wall of the limiting ring 103, and through the heat transfer between the process gas and the inner wall of the limiting ring, the process gas in the gas inlet area 10a cannot reach the required temperature for reaction, thereby preventing the process gas from reacting in advance in the gas inlet area 10a.

[0063] The cavity top cover 10 further comprises a protective cover 113 (for example, made of quartz), which is configured to cover the inner wall and the bottom surface of the limiting ring 103. The protective cover 113 can isolate the heat radiated from the reaction cavity 20 to the limiting ring 103, and also prevent the reaction by-products from adhering to the inner wall and the bottom surface of the limiting ring 103. The bottom of the protective cover 113 can be hung on the bottom surface of the limiting ring 103 through the step screw 115 (which is only an example, and other connecting parts can also be used), and the protective cover 113 is easy to install and disassemble. The protective cover 113 and the limiting ring 103 (metal material) have a thermal deformation accommodation gap, which can avoid the limiting ring 103 from being broken by the thermal expansion.

[0064] In this embodiment, the bottom surface of the gas supply part 104 is provided with a baffle plate 114 (for example, made of quartz), and the outer edge of the baffle plate 114 is lapped on the top of the protective cover 113. When the baffle plate 114 needs to be cleaned or replaced, only the step screw 115 needs to be removed, and the limiting ring 103 does not need to be removed, so the installation and removal of the baffle plate 114 is easy to operate. The baffle plate 114 is provided with a plurality of through holes corresponding to the positions of a plurality of gas outlet holes (not shown in the figure) provided on the bottom surface of the gas supply part 104. The baffle plate 114 can isolate the heat radiated from the reaction chamber 20 to the gas supply part 104, and can also prevent the reaction by-products from adhering to the gas supply part 104.

[0065] As shown in FIGS. 1 and 2, the limiting ring 103, the top cover sidewall 101, and the top cover cover plate 102 jointly form a top cover buffer cavity 10b, and the purge gas is injected into the reaction chamber 20 through the top cover buffer cavity 10b. In this embodiment, the purge gas can be argon (Ar) or hydrogen (H2). Under the pressure of the purge gas in the top cover buffer cavity 10b, the process gas or cleaning gas with corrosive property is not easy to flow into the top cover buffer cavity 10b, thereby reducing the risk of process gas leakage caused by corrosion and deformation of the top cover cover plate 102 and the top cover sidewall 101, and ensuring the safety of substrate processing.

[0066] The purge gas can also quickly carry away the heat in the top cover buffer cavity 10b, so that the inner wall of the top cover buffer cavity 10b (including the inner surface of the top cover sidewall 101, the lower surface of the top cover cover plate 102, and the outer wall of the limiting ring 103) has a lower temperature, and alloy elements are not precipitated to cause metal contamination of the reaction chamber 20. At the same time, the process gas can also be prevented from depositing on the inner wall of the top cover buffer cavity 10b, so as to avoid the particles of the deposit entering the reaction chamber 20 to cause particle contamination. The present application improves the utilization rate of the process gas, greatly reduces the frequency of maintenance of the cavity top cover 10 and the reaction chamber 20, reduces the cost of substrate processing, and improves the production efficiency.

[0067] As shown in FIGS. 1 and 2, the top of the limiting ring 103 has a uniform flow plate 105 extending radially outward, and the purge gas is injected into the top cover buffer cavity 10b through the uniform flow plate 105. Since the uniform flow plate 105 is located in the top cover buffer cavity 10b and is far away from the reaction chamber 20, warping deformation and precipitation of alloy elements caused by long-time heat radiation of the reaction chamber 20 to the uniform flow plate 105 can be effectively avoided.

[0068] The top or inner portion of the flow uniformizing plate 105 is provided with a gas uniformizing groove 1051 in gas communication with an external purge gas source. The bottom of the flow uniformizing plate 105 is provided with a plurality of gas uniformizing holes 1052 in gas communication with the gas uniformizing groove 1051 and the top cover buffer cavity 10b, so that the purge gas flowing into the top cover buffer cavity 10b from the gas uniformizing groove 1051 is homogenized. As shown in FIGS. 1 and 2, in the present embodiment, the gas uniformizing groove 1051 is opened in the top of the flow uniformizing plate 105, and the top of the gas uniformizing groove 1051 is blocked by the bottom surface of the top cover cover plate 102. Since the top surface of the flow uniformizing plate 105 contacts the bottom surface of the top cover cover plate 102, the heat of the flow uniformizing plate 105 can be quickly conducted away through the first cooling portion 121 in the top cover cover plate 102.

[0069] In the present embodiment, the flow uniformizing plate 105 is integrally arranged with the limiting ring 103 to improve the heat transfer between the flow uniformizing plate 105 and the limiting ring 103. The second cooling portion 122 is arranged in the limiting ring 103, so that the limiting ring 103 is cooled and the heat of the flow uniformizing plate 105 can be quickly conducted away at the same time. Therefore, the surface of the flow uniformizing plate 105 cannot reach the temperature required for the reaction of the process gas, and the deposition of the process gas on the surface of the flow uniformizing plate 105 can be avoided.

[0070] As shown in FIGS. 1 and 2, the flow resistance plate 106 (for example, made of quartz) is arranged at the bottom in the top cover buffer cavity 10b and surrounds the outer periphery of the limiting ring 103. The purge gas flows into the reaction cavity 20 from the gap between the flow resistance plate 106, the top cover side wall 101 and the limiting ring 103. The flow resistance plate 106 prolongs the residence time of the purge gas in the top cover buffer cavity 10b, and improves the uniformity of the distribution of the purge gas in the top cover buffer cavity 10b. The flow resistance plate 106 increases the flow resistance of the process gas flowing into the top cover buffer cavity 10b, so that the flow rate of the process gas flowing into the top cover buffer cavity 10b can be effectively reduced even when the flow rate of the process gas is high. The flow resistance plate 106 can also block the heat radiation from the reaction cavity 20 to the top cover buffer cavity 10b, which helps to reduce the temperature in the top cover buffer cavity 10b.

[0071] As shown in FIGS. 1 and 2, in the present embodiment, the flow resistance plate 106 is hung on the flow uniformizing plate 105 by the connecting rod 116. The connecting rod 116 has a small contact area with the flow resistance plate 106 and the flow uniformizing plate 105, so that the heat transferred from the flow resistance plate 106 to the flow uniformizing plate 105 through the connecting rod 116 is also small and can be ignored.

[0072] The embodiment also provides a CVD reaction device 1, as shown in FIG. 1, which has a reaction cavity 20 including a cavity sidewall 201 and a bottom plate 202. The cavity 20 is provided with the cavity top cover 10 as described in the embodiment, and the inner diameter of the top cover sidewall 101 is not less than the inner diameter of the cavity sidewall 201 at the joint therebetween, so that the top cover sidewall 101 is away from the heat source and the temperature of the top cover sidewall 101 is reduced. In addition, the inner diameter of the top cover sidewall 101 is not less than the inner diameter of the cavity sidewall 201 at the joint therebetween, so that the space of the top cover buffer cavity 10b is increased and the purge gas is distributed more uniformly in the top cover buffer cavity 10b. Preferably, the inner diameter of the top cover sidewall 101 is equal to the inner diameter of the cavity sidewall 201 at the joint therebetween, so that the cavity top cover is not subjected to shear force and the mechanical stability is improved.

[0073] In FIG. 1, the bottom of the top cover sidewall 101 has a top cover edge 1011 extending radially outward, which increases the contact area between the top cover sidewall 101 and the cavity sidewall 201 and helps to reduce the leakage of process gas from the top cover sidewall 101 and the cavity sidewall 201. A plurality of sealing rings 205 are arranged between the bottom surface of the top cover edge 1011 and the top surface of the cavity sidewall 201. As shown in FIG. 1, the position of the sealing rings 205 is separated from the gas inlet area 10a by the top cover buffer cavity 10b filled with purge gas, and the sealing rings 205 can be away from the heat source in the reaction cavity 20. The service life of the sealing rings 205 is effectively prolonged, and the risk of process gas leakage caused by failure of the sealing rings 205 is reduced. The inside of the cavity sidewall 201 is provided with a third cooling part 270, which can cool the cavity sidewall 201 and also guide away the heat of the sealing rings 205, further reducing the risk of failure of the sealing rings 205.

[0074] The bottom of the reaction cavity 20 is provided with a rotating cylinder 211, and the top of the rotating cylinder 211 is provided with a tray 212 for carrying a substrate. In the process, the process gas injected by the gas supply part 104 will be partially mixed in the process of diffusing downward, but it cannot be guaranteed that the process gas will be fully mixed when reaching the surface of the substrate. Therefore, the rotating cylinder 211 is driven to rotate at a high speed around its central axis, and the tray 212 is driven to rotate at a high speed under the action of friction between the rotating cylinder 211 and the tray 212. In this way, different types of process gas reaching the surface of the substrate are fully mixed under the driving of the high-speed rotating tray 212, so that a thin film of the required material is grown on the surface of the substrate.

[0075] As shown in FIG. 1, the inner part of the rotating cylinder 211 is further provided with a lower heater 213 for radiating heat energy to the tray 212, and the tray 212 further transfers the heat energy provided by the lower heater 213 to the substrate W, so that the temperature of the substrate surface meets the process requirements. A reflection plate 214 is arranged below the lower heater 213, and the heat radiated downward by the lower heater 213 is reflected to the tray 212 through the reflection plate 214, thereby improving the heat energy utilization rate of the lower heater 213. A heat preservation layer 215 is further arranged below the reflection plate 214, for preventing the heat of the lower heater 213 from being transmitted downward, further reducing the heat loss of the lower heater 213, and avoiding the temperature of the bottom plate 202 being too high.

[0076] The bottom plate 202 is provided with an exhaust port 203, which is in gas communication with an external exhaust device (for example, a vacuum pump, not shown in the figure). The exhaust device provides gas flow power, and the exhaust port 203 is used to exhaust the exhaust gas generated by the reaction and the part of the reaction gas which has not participated in the reaction to the outside of the reaction chamber 20.

[0077] As shown in FIG. 1, the reaction chamber 20 is further provided with an upper liner 221 and a lower liner 222 for protecting the inner side wall of the reaction chamber 20 from being contaminated. The upper liner 221 and the lower liner 222 can be made of graphite. As shown in FIG. 1, the upper liner 221 is arranged above the lower liner 222 and surrounds the inner side wall of the reaction chamber 20. The lower liner 222 is arranged between the rotating cylinder 211 and the inner side wall of the reaction chamber 20. The lower liner 222 can move between a process position and a substrate loading and unloading position. When the substrate is loaded and unloaded, the lower liner 222 is located at the substrate loading and unloading position, the robot passes through the loading and unloading port (not shown in the figure) located in the side wall 201 of the reaction chamber and the upper edge of the lower liner 222 to load and unload the substrate and / or the tray 212 below the substrate. After the loading and unloading is completed, the robot moves out, and the lower liner 222 moves upward to the process position to shield the loading and unloading port, so as to ensure the uniformity of the circumferential temperature of the substrate.

[0078] In the embodiment, the reaction chamber 20 is further provided with a mounting ring 240 (for example, made of graphite), which is arranged around the outer periphery of the upper liner 221 and coupled to the inner side wall of the reaction chamber 20. As shown in FIG. 1, the inner side wall of the reaction chamber 20 is provided with a plurality of bosses 271 along the circumferential direction of the reaction chamber 20, and the mounting ring 240 is supported by the plurality of bosses 271. The top of the upper liner 221 extends radially outward to form an extension, and the extension is loaded on the mounting ring 240.

[0079] As shown in FIG. 1, a reflective ring 230 (e.g., graphite material) is disposed between the confinement ring 103 and the upper liner 221, and the inner diameter of the reflective ring 230 is smaller than the inner diameter of the upper liner 221. The reflective ring 230 reflects the heat from the reaction cavity 20 downward, further reducing the temperature of the top cover buffer cavity 10b and the confinement ring 103. The reflective ring 230 also increases the flow resistance of the process gas entering the top cover buffer cavity 10b, effectively reducing the flow of the process gas into the top cover buffer cavity 10b even when the flow rate of the process gas is high.

[0080] In the embodiment, as shown in FIG. 1, the inner diameter of the reflective ring 230 gradually decreases in the direction from top to bottom. The inner wall of the reflective ring 230 guides the process gas flowing out of the top cover buffer cavity 10b, and directs the purge gas downward to the inner side wall of the upper liner 221. Under the pressure of the process gas, the purge gas flows downward along the inner side wall of the upper liner 221 without affecting the flow direction and distribution of the process gas, avoiding interference with the process gas. The smooth transition of the flow field in the entire reaction cavity 20 is conducive to maintaining stable growth conditions for the substrate, ensuring controllable processes in the reaction cavity 20. On the other hand, the purge gas separates the upper liner 221 and the lower liner 222 from the process gas, preventing the process gas from diffusing to the inner surfaces of the upper liner 221 and the lower liner 222, and reducing the deposition of reaction byproducts on the inner surfaces of the upper liner 221 and the lower liner 222.

[0081] As shown in FIG. 1, in the preferred embodiment, the baffle plate 106 has a first gap with the top cover side wall 101, and a second gap with the confinement ring 103. The first gap is larger than the second gap, and the purge gas in the top cover buffer cavity 10b is more likely to flow from the first gap to the outside of the reflective ring 230 and the mounting ring 240, flow through the upper surfaces of the reflective ring 230 and the mounting ring 240, and then flow into the reaction cavity 20 from the inside of the reflective ring 230 and the mounting ring 240. Since the purge gas can flow through the entire upper surface of the reflective ring 230 and the entire upper surface of the mounting ring 240, the deposition of byproducts on the reflective ring 230 and the mounting ring 240 is greatly reduced.

[0082] In order to grow high-quality thin films, it is necessary to accurately control the types of components in the process gas and the volume fraction of each component. Once the gas of a certain component in the current process is retained in a certain space (also referred to as a dead zone where the flow field is uncontrollable) in the reaction cavity 20, such as a gap, cavity, or gap between components in the reaction cavity 20, or the process gas of the previous process remaining in the above-mentioned dead zone reaches the substrate surface together with the injected process gas, the properties of the thin film grown on the substrate surface will not meet the requirements, affecting the yield of substrate processing.

[0083] The purge gas flowing out of the top cover buffer cavity 10b is more likely to flow into the gaps between the choke ring, the reflector ring 230, the mounting ring 240, the upper liner 221 and other components compared with the process gas, preventing the formation of dead zones in the reaction cavity 20 where the flow field of the process gas is uncontrollable, avoiding the process gas remaining in the dead zones, and causing the process to be uncontrollable. The purge gas forms an air curtain when flowing downward along the inner surface of the liner, preventing the process gas from diffusing into the space between the liner and the side wall 201 of the reaction cavity. Thus, the purge gas can also confine the process gas in the space surrounded by the liner (including the upper liner 221 and the lower liner 222), effectively ensuring that the volume fraction of each component reaching the substrate surface meets the process requirements, improving the utilization rate of the process gas, and ensuring the yield of substrate processing.

[0084] As shown in FIG. 1, the CVD reaction device 1 further includes a side heater 260, an upper heat insulation cylinder 251 and a lower heat insulation cylinder 252. The side heater 260 is arranged between the upper liner 221 and the inner side wall of the reaction cavity 20, and is used to heat the process gas in the reaction cavity 20.

[0085] The upper heat insulation cylinder 251 is located above the lower heat insulation cylinder 252, and the upper heat insulation cylinder 251 is arranged around the side heater 260 and the inner side wall of the reaction cavity 20, and the lower heat insulation cylinder 252 is arranged around the lower liner 222 and the inner side wall of the reaction cavity 20. By the upper heat insulation cylinder 251 and the lower heat insulation cylinder 252, the heat of the side heater 260 can be effectively limited inside the reaction cavity 20, reducing the heat loss in the reaction cavity 20 while ensuring the safety of the equipment. In the embodiment, the upper heat insulation cylinder 251 and the lower heat insulation cylinder 252 are made of graphite.

[0086] In the reaction cavity 20, the gas temperature near the side heater 260 is high, and the gas is easy to flow upward; the gas temperature near the center of the reaction cavity is low, and the gas is easy to flow downward, so it is easy to produce gas vortex above the substrate. In the embodiment, as shown in FIG. 1, the reaction cavity 20 further comprises a heat absorption cylinder 280, which is located above the tray and extends along the axial direction of the reaction cavity 20. The heat absorption rate of the heat absorption cylinder 280 is greater than the heat absorption rate of the process gas, which is used to absorb the heat emitted by the lower heater 213 and the side heater 260, and emit the absorbed heat to the central region of the reaction cavity 20 to heat the reaction gas located in the central region of the reaction cavity 20.

[0087] The heat absorption cylinder 280 reduces the radial temperature gradient inside the reaction cavity 20, avoids the generation of vortex, and makes the growth conditions of the substrate more uniform, thereby improving the thickness and uniformity of the film growth on the entire substrate. In a preferred embodiment, the inner diameter of the heat absorption cylinder 280 is greater than the diameter of the substrate, which can avoid the falling of possible particle contaminants on the heat absorption cylinder 280 to the surface of the substrate, further improving the quality of the substrate.

[0088] The above merely illustrates the specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any skilled person in the art can easily think of various equivalent modifications or replacements within the technical range disclosed by the present application, and these modifications or replacements shall be covered within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A cavity top cover, which is arranged on a reaction cavity of a CVD reaction device, characterized in that, The application relates to a chamber top cover for a reaction chamber. The chamber top cover comprises: a limiting ring located above the reaction chamber and extending along the axial direction of the reaction chamber; a gas supply part provided at the top end of the limiting ring and used for injecting process gas into the reaction chamber; a top cover side wall surrounding the outer periphery of the limiting ring; a top cover cover plate fixedly arranged at the top end of the top cover side wall and surrounding the outer periphery of the gas supply part; the limiting ring, the top cover side wall and the top cover cover plate jointly form a top cover buffer cavity; and a purge gas is injected into the reaction chamber through the top cover buffer cavity; 2. The chamber lid of claim 1, wherein, a baffle plate provided at the bottom of the top cover buffer cavity and surrounding the outer periphery of the limiting ring; the baffle plate has a gap with the top cover side wall and the limiting ring.

3. The cavity lid of claim 1, wherein The baffle plate has a first gap with the top cover side wall and a second gap with the limiting ring, and the first gap is larger than the second gap.

4. The chamber lid of claim 3, wherein, The top of the limiting ring is provided with a flow uniformizing plate extending radially outward, and the top or inner portion of the flow uniformizing plate is provided with a flow uniformizing groove in gas connection with an external purge gas source and the top cover buffer cavity.

5. The cavity top cover of claim 3, wherein, The flow uniformizing plate is integrally arranged with the limiting ring.

6. The cavity lid of claim 3, wherein The baffle plate is hung on the flow uniformizing plate through a connecting rod.

7. The cavity lid of claim 1, wherein The top cover cover plate is provided with a first cooling part, and the limiting ring is provided with a second cooling part; the distance between the second cooling part and the inner wall of the limiting ring is smaller than the distance between the second cooling part and the outer wall of the limiting ring.

8. The chamber lid of claim 7, wherein, A protective cover is further arranged to cover the inner wall and bottom surface of the limiting ring.

9. The cavity lid of claim 7, wherein, The bottom of the protective cover is hung on the bottom surface of the limiting ring.

10. The chamber lid of claim 7, wherein, The protective cover has a gap with the limiting ring.

11. The chamber lid of claim 1 wherein, The bottom surface of the gas supply part is provided with a partition plate having a plurality of through holes; and the outer edge of the partition plate is overlapped on the top of the protective cover.

12. A CVD reactor having a reaction chamber, characterized by, The inner diameter of the limiting ring gradually increases along the direction from top to bottom. The reaction chamber is provided with the chamber top cover as claimed in any one of claims 1 to 11; the inner diameter of the top cover side wall is not smaller than the inner diameter of the reaction chamber side wall at the joint between the two. The bottom of the reaction chamber is provided with a rotating cylinder capable of rotating around the central axis thereof.

13. The CVD reaction apparatus according to claim 12, wherein The top of the rotating cylinder is provided with a tray for carrying a substrate; and the tray is arranged opposite to the gas supply part.

14. The CVD reaction apparatus according to claim 13, wherein The reaction chamber is further provided with an upper bushing and a lower bushing; the upper bushing is located above the lower bushing and surrounds the inner side wall of the reaction chamber; and the lower bushing is arranged between the rotating cylinder and the inner side wall of the reaction chamber.

15. The CVD reaction apparatus according to claim 14, wherein A reflecting ring is further arranged between the limiting ring and the upper bushing; and the inner diameter of the reflecting ring is smaller than the inner diameter of the upper bushing.

16. The CVD reaction apparatus according to claim 14, wherein The inner diameter of the reflecting ring gradually decreases along the direction from top to bottom, and the inner wall of the reflecting ring guides the process gas flowing out of the top cover buffer cavity. A mounting ring is further arranged around the outer periphery of the upper bushing and the reflecting ring and coupled to the inner side wall of the reaction chamber.

17. The CVD reactor of claim 13, wherein The side heater is arranged between the upper liner and the inner sidewall of the reaction cavity for heating the process gas in the reaction cavity; the lower heater is arranged in the rotary cylinder for heating the substrate.

18. The CVD reaction apparatus according to claim 17, wherein The upper heat insulation cylinder is arranged above the lower heat insulation cylinder and surrounds the space between the side heater and the inner sidewall of the reaction cavity; the lower heat insulation cylinder surrounds the space between the lower liner and the inner sidewall of the reaction cavity.

19. The CVD reactor of claim 12, wherein, The bottom of the top cover sidewall is connected with the top of the reaction cavity sidewall; a sealing ring is arranged between the top cover sidewall and the reaction cavity sidewall.

20. The CVD reaction apparatus according to claim 12, wherein A heat absorption cylinder is further arranged in the reaction cavity, which is arranged above the tray and extends along the axial direction of the reaction cavity; the heat absorption rate of the heat absorption cylinder is greater than the heat absorption rate of the process gas.

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