Chemical vapor deposition apparatus

Abstract

A chemical vapor deposition apparatus, comprising: a reaction chamber, including a chamber sidewall and a bottom wall; a susceptor located in the reaction chamber, the susceptor including a susceptor sidewall, the susceptor sidewall and the chamber sidewall including an exhaust region therebetween; characterized in that the apparatus further comprises: a flow restrictor ring located in the exhaust region around the susceptor sidewall, the flow restrictor ring bottom wall and the chamber bottom wall including a storage space therebetween; the flow restrictor ring sidewall or bottom wall including at least one opening for allowing gas flow to pass through the opening into the exhaust chamber; and at least one exhaust duct fixed between the exhaust chamber and the reaction chamber bottom wall or sidewall to support the exhaust chamber above the storage chamber.

Description

TECHNICAL FIELD

[0001] The present application relates to a chemical vapor deposition device, in particular to an exhaust system for MOCVD reactor. BACKGROUND

[0002] Metal organic chemical vapor deposition (MOCVD) is widely used in compound semiconductor deposition, such as gallium nitride (GaN) deposition, which can eventually generate a variety of epitaxial films for manufacturing LED devices, power semiconductor devices, laser devices. The main reaction gas is trimethyl gallium (TMG), which produces a large amount of particulate pollutants containing organic and inorganic metals in the reaction, which requires the optimization of the design of the exhaust system to achieve three goals: 1. Preventing the blockage of the exhaust passage by pollutants or other debris; 2. Ensuring the uniformity of the reaction gas flow distribution on the upper susceptor, 3. Preventing the backflow of particulate pollutants to the upper susceptor causing semiconductor device defects.

[0003] To this end, the patent CN106191809B submitted by the same applicant proposes a technical solution as shown in Figure 1 The technical solution includes a reaction cavity surrounded by a cavity side wall 100, a cavity bottom wall, and a cavity top cover. The inner top of the cavity includes a gas shower head 21 for gas inlet, and a liftable shielding cylinder 62 located around the gas shower head 21 in the cavity, wherein the shielding cylinder can be driven by a driving device 64, and a water cooling channel is usually provided in the shielding cylinder to cool the shielding cylinder 62. The bottom of the reaction cavity opposite to the gas shower head 21 is a susceptor 14 for supporting the substrate 15 to be processed. The heater 12 below the susceptor can also be provided with a rotating drive device 24 to support and drive the susceptor 14. The rotating drive device can be a cylindrical rotating shaft driving the center of the susceptor or a rotating cylinder driving the outer edge of the susceptor. The outer periphery of the susceptor 14 below is provided with a susceptor side wall 16 to isolate the heater 12 inside the susceptor side wall 16 from the exhaust system outside. The upper high-speed rotating (>1000rpm) susceptor makes the gas flow accelerated to flow to the shielding cylinder 62, and then refracts on the inner wall of the shielding cylinder 62 to flow downward at high speed into the lower exhaust system. The exhaust system includes a separation device 139 to separate the exhaust area between the susceptor side wall 16 and the cavity side wall 100 into a storage cavity and an exhaust cavity distributed in the inner and outer directions. The solid pollutants fall into the storage cavity to accumulate, and the reaction gas flows through the gas flow opening 137 into the exhaust cavity, and then through the exhaust pipe 138 and the downstream air pump 136 to be discharged from the reaction cavity.

[0004] The inventor has further found that the scheme can greatly improve the maintenance cycle of the reaction chamber, but also has defects: as the accumulation of contaminants in the storage chamber, when filled up to near the gas flow opening 137, the reaction gas flow 18, in addition to a part of the gas flow opening 137 into the exhaust chamber, a large part of the gas flow branch 19 will be reflected upward after impacting the upper surface of the contaminants, and the gas flow branch 19 will be reflected upward to the shielding cylinder and the base direction, and the flow rate of the gas flow branch 19 is large enough to push the contaminants to the upper substrate 15, so that the semiconductor devices on the substrate are defective, affecting the yield of the final semiconductor devices.

[0005] Therefore, it is necessary to develop a new exhaust system to further improve the production efficiency and device yield of the MOCVD equipment. SUMMARY

[0006] The purpose of the present application is to provide a chemical vapor deposition device, comprising: a reaction chamber, including a chamber side wall and a bottom wall; a base located in the reaction chamber, the base includes a base side wall, and the base side wall and the chamber side wall include an exhaust area, the gas flow from above the base passes through the exhaust area and is discharged from the reaction chamber; characterized in that, the device further comprises: a constraint ring located in the exhaust area and surrounding the base side wall, the constraint ring includes a top plate, a side wall and a bottom wall, and the constraint ring bottom wall and the chamber bottom wall form a storage chamber; the constraint ring top plate extends downwardly, so that the contaminants above the constraint ring top plate can slide downwardly; the bottom space of the storage chamber is used for accumulating contaminants, and the top space is used for lateral diffusion of the gas flow, so that at least part of the gas flow flows laterally in the lateral diffusion space after passing through the constraint ring side wall. The present application can store a large amount of solid contaminants while preventing the return flow of contaminant particles to the upper substrate, greatly prolonging the maintenance cycle while improving the substrate processing quality.

[0007] The constraint ring can be hollow, and the side wall or the bottom wall includes at least one opening for allowing the gas flow to enter the constraint ring through the opening, and the inner side wall or the outer side wall of the hollow constraint ring is fixed to the base side wall or the chamber side wall. Further, the constraint ring can include an inner side wall and an outer side wall supporting two inclined downward top plates above. It can also include at least one exhaust duct connected between the constraint ring and the bottom wall or the side wall of the reaction chamber to discharge the gas in the constraint ring.

[0008] The radial width of the constraint ring is set such that the cross-sectional area of ​​the airflow passing over the constraint ring is greater than 1.5 times the cross-sectional area of ​​the airflow passing over the sidewall of the constraint ring, ensuring that the airflow velocity over the sidewall of the constraint ring is significantly greater than that of the airflow above. High-speed airflow channels exist between the inner sidewall of the constraint ring and the sidewall of the base, and / or between the outer sidewall of the constraint ring and the sidewall of the cavity; ideally, the cross-sectional area of ​​the airflow channel above the constraint ring is greater than or equal to twice the cross-sectional area of ​​the high-speed airflow channel, and less than ten times.

[0009] Above the exhaust area within the reaction chamber of this invention, a shielding cylinder surrounds the reaction space above the base, and a coolant channel is provided inside the shielding cylinder. The inner sidewall of the base includes a heater located below the base, and also includes a rotating shaft for connecting to the center of the base or a rotating cylinder for connecting to the outer edge of the base.

[0010] To prevent substrate fragments from getting stuck at the top of the constraint ring in this invention, the top plate of the constraint ring and the side wall of the constraint ring can move relative to each other. This relative movement includes the top plate of the constraint ring moving up and down or rotating in a circular motion. The top plate of the constraint ring, which can rotate in a circular motion, has protrusions extending in the vertical direction, allowing the size or position of the substrate fragments to be changed during the circular motion. Alternatively, the area on the inner side of the cavity side wall corresponding to the top plate of the constraint ring includes multiple arc-shaped recesses, each containing a baffle. The front of the baffle is conformal to the inner wall of the reaction cavity, and the back of the baffle includes a drive rod that allows the baffle to reciprocate towards the center of the reaction cavity.

[0011] The invention may further include a gas diffusion ring, the sidewall of which has an opening connecting to a lateral diffusion space in the storage cavity, allowing gas flow to exit the reaction cavity via the gas diffusion ring after passing through the lateral diffusion space. The gas diffusion ring is connected to the lower part of the cavity via at least one exhaust pipe. The diffusion ring is connected to the sidewall of the cavity or the sidewall of the base and is located below the constraint ring. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of an existing MOCVD reactor.

[0013] Figure 2 This is a schematic diagram of the first embodiment of the exhaust system of the present invention.

[0014] Figure 3 This is a schematic diagram of the second embodiment of the exhaust system of the present invention.

[0015] Figure 4 This is a schematic diagram of the third embodiment of the exhaust system of the present invention.

[0016] Figure 5 This is a schematic diagram of the dimensions and area division of the third embodiment of the exhaust system of the present invention.

[0017] Figure 6 This is a schematic diagram of the structure and method of the exhaust system of the present invention for preventing substrate fragment blockage.

[0018] Figure 7 This is a schematic diagram of the second type of structure and method for preventing substrate fragment blockage in the exhaust system of the present invention.

[0019] Figure 8a This is a schematic diagram of the fourth embodiment of the exhaust system of the present invention.

[0020] Figure 8b This is a schematic diagram of the fifth embodiment of the exhaust system of the present invention.

[0021] Figure 9a , 9b This is a schematic diagram of the third type of anti-substrate fragment blockage structure of the exhaust system of the present invention. Detailed Implementation

[0022] The following is based on Figure 2 Figure 8 illustrates a preferred embodiment of the present invention.

[0023] like Figure 2 As shown, the present invention provides an MOCVD reactor, the overall structure of which is similar to... Figure 1The basic structure is the same as shown, with the main difference being the improvement in the exhaust system structure. The exhaust system includes a flow-limiting ring, the hollow interior of which forms an exhaust chamber 132. The exhaust chamber 132 is surrounded by a top plate 133a, exhaust chamber sidewalls 133b and 133c, and part of the base sidewall 16. An airflow opening 130 is provided on the exhaust chamber sidewall 133b, allowing the post-reaction airflow to flow laterally into the exhaust chamber 132 through the airflow opening 130. Simultaneously, contaminants falling from above can slide down the top plate 133a into the storage chamber 131 below the exhaust chamber 132. In this invention, the space below the exhaust chamber and above the bottom wall 110, from the base sidewall 16 to the inner wall of the reaction chamber, all constitute the storage chamber 131. Therefore, the same volume of solid contaminants can be distributed over a larger area, and the rate of contaminant accumulation and rise is slower than in existing technologies. Furthermore, before the pollutant accumulation height reaches the bottom wall 13c of the exhaust chamber, a transverse gas diffusion space is formed below the bottom wall 133c of the exhaust chamber. At this time, part of the post-reaction gas flow enters the gas flow opening 130 through path 18, while the remaining part is separated into two branch gas flows, 19a and 19b. Branch gas flow 19a will decelerate after multiple collisions with surrounding solids in the gas diffusion space and will not generate a high-speed upward gas flow. Branch gas flow 19b, after being diverted by 19a, has a significantly reduced flow rate and velocity, so it cannot push the pollutant particles to the height above the base 14. The exhaust chamber 132 forms an annular gas diffusion chamber. Multiple exhaust pipes 17' are set at multiple different azimuth angles, passing through the storage chamber 131 and supporting the exhaust chamber 132. Finally, the gas is extracted to the outside of the reaction chamber through the exhaust pipes. In the above embodiments, the exhaust chamber 132 shares the same inner sidewall and part of the base sidewall. Alternatively, the outer sidewall of the exhaust chamber can be shared with the sidewall of the cavity. Both are embodiments of the present invention. In these embodiments, it is not necessary to additionally provide an exhaust pipe 17' to support and fix the exhaust chamber 132. The exhaust pipe is directly provided on the outer sidewall shared with the exhaust chamber 132 and connected to the suction pump. Alternatively, an additional support structure can be provided, such as a support rod extending upward from the bottom wall of the cavity to support the exhaust chamber 132. The exhaust pipe 17 is only connected to the exhaust chamber as an airflow passage and does not need to provide stable support.

[0024] like Figure 3 The image shows a second embodiment of the MOCVD reactor of the present invention, whose structure is similar to... Figure 2The embodiments shown are basically the same, with the main difference being that the exhaust chamber 132 is located between the base sidewall 16 and the cavity sidewall 100, and is independently suspended above the storage cavity 131. The exhaust chamber 132 includes two top plates 134a extending radially inward and outward, two exhaust chamber sidewalls 134b located below each top plate 134a, each sidewall having an opening 130, and a bottom wall 134c. Alternatively, there may be only one exhaust chamber top plate, sloping downward in one direction (e.g., outward). This would result in different flow rates of air passing through the inner and outer sidewalls of the exhaust chamber, but it would still achieve the purpose of the invention. In this exhaust system structure, the main airflow enters the exhaust chamber 132 via the paths shown in 18a and 18b, while the remaining airflow diffuses along the paths shown in 19a1 and 19a2 in the lateral diffusion space below the bottom wall 134c, ultimately resulting in a significant reduction in velocity after the multiple airflows collide and mix. Because the airflow channels between the two exhaust chamber sidewalls 134b and the base sidewall 16 and reaction chamber wall 110 are narrow, large streams of air will not appear. Figure 2 The airflow along the sidewalls (16, 100) shown in Figure 19b is upward. This ultimately prevents the high-speed backflow of airflow to the upper base position, ensuring stable and reliable substrate growth quality.

[0025] like Figure 4 The image shows a third embodiment of the MOCVD reactor of the present invention, whose structure is similar to... Figure 2 The embodiments shown are basically the same, with the main difference being that the opening 130” of the exhaust chamber 132 is located on the bottom wall 134c of the exhaust chamber. In this case, besides the main airflows 18a and 18b bypassing the exhaust chamber 132 from the inner and outer sides respectively to reach the opening 130”, the remaining airflows will also diffuse laterally between the bottom wall 134c and the top surface of the pollutant accumulation layer, forming a counter-current effect, significantly reducing the airflow velocity, and ultimately preventing high-speed backflow to the upper base position. The exhaust pipe 17 can be located either below the exhaust chamber 132 or on the outer wall of the exhaust chamber 132, extending outwards through the side wall 100 of the chamber, ultimately allowing gas to exit the reaction chamber.

[0026] The openings (130, 130', 130") described in the various embodiments of the present invention can be multiple small holes arranged circumferentially, multiple arc-shaped air grooves, or annular air grooves. As long as the main airflow can be effectively passed through, the purpose of the present invention can be achieved. The opening gap width of the present invention is preferably less than 20 mm, and ideally less than 10 mm, to form an effective airflow constraint and avoid affecting the uniformity of airflow.

[0027] Figure 5Another variant embodiment of the present invention is shown, where the bottom wall of the exhaust region is not flat but a circular groove that is recessed downward in the center. Such a storage cavity can form a relatively large gas diffusion space directly below the opening at the bottom of the exhaust cavity while storing a large amount of solids. On the other hand, the size of the exhaust cavity and the distances between the side wall 134b of the exhaust cavity and the side wall 16 of the base and the side wall 100 of the cavity can be further optimized to improve the air flow distribution. The cross-section of the air flow channel above the exhaust cavity 132 is circular, and its cross-sectional area is proportional to the distance D0 between the side wall 16 of the base and the side wall 100 of the cavity. There is a distance D1b between the inner side wall of the exhaust cavity 132 and the side wall 16 of the base, and a distance D1a between the outer side wall of the exhaust cavity and the side wall 100 of the cavity, where D1a + D1b < D0 / 2, that is, the cross-sectional area of the air flow in the X region flowing above the exhaust cavity is more than twice the sum of the cross-sectional areas of the two air flow branches (Y regions) flowing through the side walls of the exhaust cavity below. Since the total amount of air flow through the X region and the Y region is the same, as the cross-section of the Y region becomes less than 1 / 2 of the upstream X region, the flow velocity in the Y region will increase to more than twice the upstream flow velocity. Then the air flow laterally diffuses in the region (Z) below the exhaust cavity and decelerates again to a speed close to that of the upstream X region, and finally reaches the opening 130” at the bottom of the exhaust cavity and is discharged from the exhaust cavity. The smaller the values of D1a and D1b, the greater the flow velocity in the Y region, and the smaller the eddy current velocity generated by the multiple collisions between the air flow and the internal hardware or solid pollutants in the lower Z region, so that the pollutant particles cannot diffuse upward through the high-speed air flow in the two Y regions on both sides. However, the values of D1a and D1b cannot be too small. For example, if D1a < D0 / 10, the air flow channel in the Y region is too small, which will cause the air flow at the junction of the upstream X region and the Y region to not pass through completely and quickly, resulting in serious air flow reflux, which is not conducive to the air flow distribution above the base. The cross-sectional area of the air flow channel in the X region needs to be more than 1.5 times the cross-sectional area of the air flow in the Y region to make the air flow velocity in the Y region large enough and the gas molecule density high enough, so that the gas rebounded and flowed back in the lower Z region cannot break through the high-density and high-velocity air curtain formed by the Y region, avoiding pollutant reflux. The relatively narrow Y region channel forms a constraint on the air flow, and the two turns of the air flow in the Z region and its upward entry into the exhaust cavity will also form an obvious resistance to the air flow. Therefore, the size of the original opening 130” needs to be less than 10 mm to meet the technical requirements of air flow constraint, which are shared by the above two characteristics. The opening size can be slightly larger than the original design, such as 10 - 25 mm. Such an opening size can further improve the exhaust efficiency of the exhaust cavity.

[0028] The present invention provides several embodiments in which an exhaust chamber, a lateral gas diffusion space, and a storage chamber are stacked sequentially. The gas diffusion chamber and the storage chamber have a large lateral width, which makes the accumulation height of deposited pollutants rise more slowly. The wide lateral gas diffusion space allows the branch airflows (19a, 19a1, 19a2) other than the main airflow to diffuse and collide with each other in the lateral diffusion space, ultimately reducing the speed of these airflows to a sufficiently low level so that these airflows cannot push the particulate pollutants in the lower storage chamber back to the height of the upper base.

[0029] The present invention also provides another embodiment, such as Figure 8a As shown, a flow-limiting ring 233 is provided at the upper part of the exhaust area. The outline of the flow-limiting ring 233 is the same as the external outline of the exhaust chamber described in the other embodiments above, and also includes an inclined top plate 233a, a vertical side wall 233b, and a bottom wall 233c. However, no openings for exhaust are provided on the side wall 233b or the bottom wall 233c. Instead, an opening is provided on the side wall 100 of the chamber below the flow-limiting ring, and a gas diffusion ring 25 is provided on the outside of the side wall 100 of the chamber. The gas diffusion ring 25 is connected to the suction pump through multiple exhaust pipes 17. In this exhaust structure, the airflow is restricted to a small cross-sectional area (spacing D1c) after passing through the large cross-sectional area (spacing D0) above the flow-limiting ring 233. Finally, after turning, the airflow diffuses through a lateral diffusion channel with a larger cross-sectional area (spacing D2) to the opening 230 located on the side wall of the chamber. Due to the significantly reduced cross-sectional area of ​​the airflow, the airflow is concentrated and forms a high-speed airflow between the sidewall 233b of the flow-limiting ring and the sidewall 16 of the base. This airflow then decelerates again in the lateral gas diffusion space below the flow-limiting ring, causing the contaminant particles falling from above to be deposited at the bottom of the storage cavity 131. Besides some of the laterally diffused airflow successfully passing through the opening 230 into the gas diffusion ring 25, some of the airflow impacts the cavity sidewall 100 around the opening 230 and then rebounds to form a vortex 19c. However, the velocity of the vortex 19c is significantly lower than the aforementioned high-speed airflow, so this reverse vortex 19c cannot pass through the dense and high-speed downward airflow to push the contaminants to the surface of the upper substrate. Therefore, the embodiment shown in Figure 8 also achieves the technical effect of allowing contaminants to accumulate in large quantities within the storage cavity, improving the cavity maintenance cycle, and preventing particulate matter from being returned to the upper substrate by the airflow, which is an embodiment of the present invention. Figure 8b The figure shown is another modified embodiment of the present invention, whose basic structure is the same as that of the present invention. Figure 8a The embodiments shown are the same, the main difference being that the gas diffusion ring 25' is disposed inside the cavity sidewall 100, and the exhaust pipe 17 is also disposed inside the cavity sidewall 100 accordingly. Figure 8bIn the illustrated embodiment, the downward airflow diffuses laterally after a bend, reaching the gas diffusion ring 25' a short distance. It then enters the airflow diffusion ring through the opening 230' on the gas diffusion ring 25', and is subsequently discharged from the cavity by the exhaust pipe 17 below. This embodiment still maintains the three different airflow cross-sectional area ratios, thus achieving the desired effect. Figure 8a The technical effects are basically the same as those of the embodiments shown. In addition to being disposed on the cavity sidewall 100 as described above, the flow-limiting ring of the present invention can also be disposed on the base sidewall 16, or it can include two opposing limiting ring parts, respectively disposed on the cavity sidewall 100 and the base sidewall 16, to jointly form an airflow constraint structure. This allows the airflow to be constrained to a channel with a narrow airflow cross-section, then turn below the constraint ring, and then diffuse laterally in the lateral diffusion space, finally reaching the airflow diffusion ring. The space below the lateral diffusion space is the space where pollutants accumulate.

[0030] This invention is applied to, for example Figure 1 The existing MOCVD reaction chamber has certain technical problems. The substrate, rotating at high speed on the base, warps due to thermal deformation and other reasons, and is then flung off the base by centrifugal force. After impacting the shielding cylinder 62, it forms multiple fragments that fall into the lower exhaust area. Since the substrate size is larger than the airflow channel size in the exhaust area, besides some substrate fragments falling vertically and directly passing through the narrow airflow channel to the lower storage chamber 131, there is a high probability that substrate fragments will be laterally stuck between the inclined top plate (133a, 134a) and the base sidewall 16 or the chamber sidewall 100. These stuck substrate fragments cause severely uneven airflow distribution and are difficult to remove. Therefore, the inventors have proposed further improvements, such as... Figure 6 The diagram shown is a partial enlarged view of the exhaust area of ​​the present invention. At the end of each process cycle, the inclined top plate of the exhaust chamber 132 is individually lifted, causing one end of the substrate fragment S to rise significantly until the fragment S is basically vertical, after which it slides down into the storage chamber below. Figure 7 The diagram shows a partial enlarged view of the exhaust region of the present invention. Multiple corresponding recesses are provided on the inner side of the cavity sidewall 100, corresponding to the inclined top plate. These recesses are connected to the inner surface of the cavity sidewall 100 via two upper and lower transition steps 105. Each recess contains an arc-shaped baffle 101, which is conformal to the inner surface of the cavity sidewall, forming a continuous airflow channel. During the reaction process, if a substrate fragment S is detected stuck between the baffle and the inclined top plate of the exhaust chamber, the drive rod 103 can be moved backward a certain distance, causing one end of the substrate fragment to slide downwards. Ultimately, the entire substrate fragment falls into the lower storage chamber, or one end of the substrate fragment slides to the lower transition step 105. Then, when the baffle 101 returns to its initial position, it can push the fragment towards the reaction chamber, causing the substrate fragment to fall into the lower storage chamber.

[0031] The inclined top plate of the exhaust chamber is not fixedly connected to the lower exhaust chamber sidewall and bottom wall, but is supported by a sliding support device. A gear or other drive device rotates the inclined top plate along the rotation axis 24 at the center of the reaction chamber. When a substrate fragment is stuck between the exhaust chamber top plate 133a and the chamber sidewall 100, the first end contacts the inclined top plate, and the second end contacts the base sidewall 16 or the chamber sidewall 100. As the inclined top plate continues to rotate, the substrate fragment is driven by friction, causing the first end to move circumferentially. This changes the substrate fragment's orientation, allowing it to slide into the lower storage chamber when its plane is nearly vertical, thus preventing it from getting stuck in the exhaust area. To prevent the substrate fragment from maintaining a balanced posture and continuously sliding on the inclined top plate without rotation, grooves or protrusions extending vertically can be provided on the upper surface of the inclined constraint ring top plate, forming a low point below the surface and a high point protruding from the surface. Figure 9a For the present invention Figure 2 The schematic diagram of the structure of the top plate 133a of the exhaust chamber 133 in the embodiment shown is as follows: Figure 9b for Figure 9a A horizontal cross-section of the top plate 133a. The falling substrate fragment is tightly contacted by the inclined constraint ring top plate 133a and held in its initial position. As the inclined top plate 133a rotates, the protrusion 139 near the contact point with the substrate fragment slightly lifts the fragment upwards, preventing it from being in close contact with the inclined top plate. Simultaneously, the protrusion can force the first end of the substrate fragment to rotate with the inclined top plate. Both movements disrupt the original equilibrium posture of the substrate fragment. After multiple cycles, the posture of the substrate fragment is adjusted to a near-vertical state, ultimately rendering the lateral friction at both ends insufficient to support the fragment, causing it to fall vertically downwards. Furthermore, the protrusion may further crush the substrate fragment, causing it to break into smaller fragments that slide into the lower storage cavity. The rotating inclined top plate proposed in this invention does not affect the airflow distribution, so it can be continuously used during the process without needing to wait until the process ends for remedial action, thus maintaining long-term stable process performance.

[0032] This invention provides a flow-limiting ring located in the upper space of the exhaust region, compressing the cross-sectional area of ​​the airflow channel to less than half of the cross-sectional area of ​​the airflow above the flow-limiting ring. This creates a high-speed and dense airflow around the sidewall of the flow-limiting ring. Upon reaching the area below the flow-limiting ring, the airflow diffuses in a large lateral space, further reducing its velocity. The airflow then reaches an opening located on one of the following: the bottom wall of the flow-limiting ring, the sidewall of the cavity, or the sidewall of the base. The gas is then gathered by a gas diffusion ring downstream of the opening on the hollow flow-limiting ring, the sidewall of the cavity, or the sidewall of the base, and discharged from the cavity through an exhaust pipe. The hollow flow-limiting ring, connected to the outside via an exhaust pipe, constitutes the exhaust chamber. Alternatively, it can be... Figure 8a , 8bThe hollow current-limiting ring shown is not connected to the outside world and is used only as a current-limiting ring. The above-mentioned different modifications all constitute modified embodiments of the present invention.

[0033] This invention can be used in the aforementioned MOCVD equipment, as well as in other chemical vapor deposition equipment that generates a large amount of pollutants, such as PECVD or other thin film deposition processes that use precursor gas reactors containing organic groups. In such reactors, a large amount of pollutant deposits may be formed downstream of the reaction zone, and the structural design of this invention can also be used.

[0034] It should be understood that, when used in this specification and the appended claims, the term "comprising" indicates the presence of the described feature, integral, step, operation, element and / or component, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0035] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the application. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0036] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of the present invention. After reading the above content, various modifications and substitutions to the present invention will be obvious to those skilled in the art. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A chemical vapor deposition apparatus comprising: a reaction chamber comprising a chamber sidewall and a chamber bottom wall; a susceptor positioned within the reaction chamber, the susceptor comprising a susceptor sidewall, the susceptor sidewall and the chamber sidewall comprising an exhaust region therebetween through which gas flow from above the susceptor is exhausted from the reaction chamber; and characterized by: a confinement ring positioned above the exhaust region and surrounding the susceptor sidewall, the confinement ring comprising a top wall, a sidewall, and a bottom wall, the confinement ring bottom wall and the chamber bottom wall comprising a storage cavity therebetween; the confinement ring top wall extending downwardly at an angle such that contaminants above the confinement ring top wall can slide downwardly; the storage cavity comprising a lower portion for accumulating contaminants and an upper portion for lateral diffusion of gas flow such that at least a portion of the gas flow laterally flows in the lateral diffusion space after passing through the confinement ring sidewall; the confinement ring comprising a high velocity gas flow channel between the confinement ring inner sidewall and the susceptor sidewall and / or between the confinement ring outer sidewall and the chamber sidewall; the gas flow channel above the confinement ring having a cross-sectional area that is greater than or equal to 2 times and less than 10 times the cross-sectional area of the high velocity gas flow channel; and the gas flow channel in the upper portion of the storage cavity below the confinement ring bottom wall for lateral diffusion of gas flow having a cross-sectional area that is greater than the cross-sectional area of the high velocity gas flow channel such that the gas flow in the lateral diffusion space is drawn away at a flow rate that is less than the flow rate of the gas flow in the high velocity gas flow channel. the confinement ring is hollow and the sidewall or the bottom wall comprises at least one opening for allowing gas flow to enter the confinement ring through the opening; the confinement ring inner sidewall or the confinement ring outer sidewall is fixed to the susceptor sidewall or the chamber sidewall; the confinement ring comprises an inner sidewall and an outer sidewall that support two top walls above the confinement ring, respectively, the two top walls extending downwardly at an angle; at least one exhaust duct is connected between the confinement ring and the chamber bottom wall or the chamber sidewall for exhausting gas from the confinement ring; the radial width of the confinement ring is configured such that the cross-sectional area of the gas flow above the confinement ring is greater than 1.5 times the cross-sectional area of the gas flow through the confinement ring sidewall; a shield cylinder is positioned above the exhaust region in the reaction chamber and surrounds the reaction space above the susceptor, the shield cylinder comprising a cooling liquid channel therein; the susceptor sidewall comprises a heater positioned below the susceptor; and the susceptor comprises a rotating shaft connected to the center of the susceptor or a rotating cylinder connected to the outer edge of the susceptor; the confinement ring top wall is movable relative to the confinement ring sidewall, the relative movement comprising up-and-down movement of the confinement ring top wall or circumferential movement of the confinement ring top wall; the confinement ring top wall comprises a protrusion extending in the up-and-down direction, the protrusion being configured to change the size or position of a substrate fragment when the confinement ring top wall is circumferentially moved; the chamber sidewall comprises a plurality of arc-shaped recesses in the area corresponding to the confinement ring top wall, each of the arc-shaped recesses comprising a baffle, the front surface of the baffle being conformal to the inner wall of the reaction chamber, and the back surface of the baffle comprising a driving rod such that the baffle can reciprocate toward the center of the reaction chamber; and a gas diffusion ring is positioned below the confinement ring, the gas diffusion ring comprising an opening in the sidewall thereof, the opening being connected to the lateral diffusion space in the storage cavity such that the gas flow passes through the lateral diffusion space and is exhausted from the reaction chamber through the gas diffusion ring. ​ ​ ​ ​ ​ ​ ​ 2. The chemical vapor deposition apparatus according to claim 1, wherein ​ 3. The chemical vapor deposition apparatus according to claim 2, wherein ​ 4. The chemical vapor deposition apparatus according to claim 2, wherein ​ 5. The chemical vapor deposition apparatus of claim 2, wherein ​ 6. The chemical vapor deposition apparatus of claim 1, wherein ​ 7. The chemical vapor deposition apparatus of claim 1 wherein, ​ 8. The chemical vapor deposition apparatus of claim 1 wherein, ​ 9. The chemical vapor deposition apparatus of claim 1 wherein, ​ 10. The chemical vapor deposition apparatus of claim 9, wherein ​ 11. The chemical vapor deposition apparatus of claim 1 wherein, ​ 12. The chemical vapor deposition apparatus of claim 1 wherein, ​ 13. The chemical vapor deposition apparatus of claim 12, wherein ​ 14. The chemical vapor deposition apparatus of claim 12, wherein The diffusion ring is connected to the side wall of the cavity or the base side wall and is located below the confinement ring.

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