Chemical vapor deposition device

Abstract

A chemical vapor deposition device comprises: a reaction chamber comprising a chamber side wall and a bottom wall; the base is located in the reaction cavity, the base comprises a base side wall, and an exhaust area is arranged between the base side wall and the cavity side wall; the device is characterized in that the device further comprises a flow limiting ring located in the exhaust area and surrounding the side wall of the base, and a storage space exists between the bottom wall of the flow limiting ring and the bottom wall of the cavity; the side wall or the bottom wall of the flow limiting ring comprises at least one opening used for enabling airflow to enter the exhaust cavity through the opening. And the at least one exhaust pipeline is fixed between the exhaust cavity and the bottom wall or the side wall of the reaction cavity so as to support the exhaust cavity to be positioned above the storage cavity.

Description

Technical Field

[0001] The invention relates to a chemical vapor deposition device, in particular to an exhaust system for an MOCVD reactor. Background Art

[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 used to manufacture LED devices, power semiconductor devices, and laser devices. The main reaction gas is trimethylgallium (TMG), which will produce a large number of particulate pollutants containing organic matter and inorganic metals during the reaction. The exhaust system needs to be optimized to achieve three goals: 1. Prevent pollutants or other debris from blocking the exhaust channel; 2. Ensure the uniformity of the reaction gas flow distribution on the upper base; 3. Prevent particulate pollutants from flowing back to the upper base and causing semiconductor device defects.

[0003] For this purpose, the patent CN106191809B submitted by the same applicant proposes the following Figure 1 The technical solution shown. The technical solution includes a reaction chamber, which is surrounded by a chamber side wall 100, a chamber bottom wall, and a chamber top cover. The top of the chamber includes a gas shower head 21 for air intake, and a liftable shielding cylinder 62 located in the chamber and surrounding the gas shower head 21, 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 chamber opposite to the gas shower head 21 is a base 14 for supporting a substrate 15 to be processed. Below the base is a heater 12, and a rotating drive device 24 can be optionally provided to support and drive the base 14, which can be a cylindrical rotating shaft driving the center of the base or a rotating cylinder driving the outer edge of the base. A base side wall 16 is provided on the periphery below the base 14 to isolate the heater 12 on the inner side of the base side wall 16 from the exhaust system on the outside. The high-speed rotating (>1000rpm) base above accelerates the airflow and flows toward the shielding tube 62. After being refracted by the inner wall of the shielding tube 62, the airflow flows downward at high speed into the exhaust system below. The exhaust system includes an isolation device 139 that separates the exhaust area between the base side wall 16 and the cavity side wall 100 into a storage chamber and an exhaust chamber distributed in the inside-outside direction. Solid pollutants fall into the storage chamber and accumulate. After the reaction, the airflow enters the exhaust chamber through the airflow opening 137, and is then discharged from the reaction chamber through the exhaust pipe 138 and the downstream vacuum pump 136.

[0004] After further research by the inventors, it was found that although this solution can greatly improve the maintenance cycle of the reaction chamber, it also has defects: as the pollutants accumulate in the storage chamber and fill up to close to the air flow opening 137, in addition to a portion of the post-reaction air flow 18 entering the exhaust chamber through the air flow opening 137, a large portion of the air flow branch 19 will impact the upper surface of the pollutants and rebound through the inner wall of the reaction chamber to flow upward toward the shielding tube and the base. In addition, the high flow rate of the air flow branch 19 can push the pollutants to the upper substrate 15, causing defects in the semiconductor devices on the substrate, thereby affecting the yield of the final semiconductor devices.

[0005] Therefore, the industry needs to develop new exhaust systems to further improve the production efficiency and device yield of MOCVD equipment. Summary of the invention

[0006] The object of the present invention 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 including a base side wall, an exhaust area between the base side wall and the chamber side wall, and the airflow from the top of the base is discharged from the reaction chamber through the exhaust area; the device is characterized in that the device also includes: a confinement ring located in the exhaust area and surrounding the side wall of the base, the confinement ring including a top plate, a side wall and a bottom wall, and there is a storage chamber between the bottom wall of the confinement ring and the bottom wall of the chamber; the top plate of the confinement ring extends downwardly in an inclined manner so that the pollutants above the top plate of the confinement ring can slide down; the bottom space of the storage chamber is used to accumulate pollutants, and the top space is used for lateral diffusion of the airflow, so that after the airflow passes through the side wall of the confinement ring, at least part of the airflow flows laterally in the lateral diffusion space. The present invention can prevent pollutant particles from flowing back to the upper substrate while storing a large amount of solid pollutants, greatly extending the maintenance cycle while improving the substrate processing quality.

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

[0008] The radial width of the confinement ring is set so that the cross-sectional area of ​​the airflow passing through the top of the confinement ring is greater than 1.5 times the cross-sectional area of ​​the airflow passing through the side wall of the confinement ring, so as to ensure that the velocity of the airflow passing through the side wall of the confinement ring is significantly greater than the airflow above. A high-speed airflow channel exists between the inner side wall of the confinement ring and the side wall of the base and / or between the outer side wall of the confinement ring and the side wall of the cavity; optimally, the cross-sectional area of ​​the airflow channel above the confinement ring is greater than or equal to 2 times, and less than 10 times, the cross-sectional area of ​​the high-speed airflow channel.

[0009] The invention provides a shielding cylinder above the exhaust area in the reaction chamber, surrounding the reaction space above the base, wherein a cooling liquid channel is arranged in the shielding cylinder. The inner side of the side wall of the base includes a heater located below the base, and also includes a rotating cylinder for connecting to a rotating shaft at the center of the base or to the outer edge of the base.

[0010] In order to prevent substrate fragments from getting stuck on the top of the confinement ring of the present invention, the top plate of the confinement ring and the side wall of the confinement ring can move relative to each other, and the relative movement includes the top plate of the confinement ring being able to move up and down or the top plate of the confinement ring making a circular motion. The top plate of the confinement ring that can rotate in a circular motion is provided with a ridge extending in the up and down direction, so that the size or position of the substrate fragments can be changed when the top of the confinement ring makes a circular motion. Alternatively, the inner side surface of the side wall of the cavity and the area corresponding to the top plate of the confinement ring include a plurality of arc-shaped recessed portions, and the recessed portion includes a baffle, the front side of the baffle is conformal to the inner wall of the reaction chamber, and the back side of the baffle includes a driving rod so that the baffle can reciprocate toward the center of the reaction chamber.

[0011] The present invention may also include a gas diffusion ring, wherein the side wall of the gas diffusion ring includes an opening, and the opening is connected to the lateral diffusion space in the storage chamber, so that the gas flow passes through the lateral diffusion space and then exits the reaction chamber through the gas diffusion ring. The gas diffusion ring is connected to the bottom through at least one exhaust pipe. The diffusion ring is connected to the side wall of the chamber or the side wall of the base, and is located below the confinement ring. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the structure of a MOCVD reactor in the prior art.

[0013] Figure 2 Schematic diagram of the first embodiment of the exhaust system of the present invention.

[0014] Figure 3 Schematic diagram of the second embodiment of the exhaust system of the present invention.

[0015] Figure 4 Schematic diagram of the third embodiment of the exhaust system of the present invention.

[0016] Figure 5 It 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 It is a schematic diagram of a structure and method for preventing the exhaust system of the present invention from being blocked by substrate fragments.

[0018] Figure 7 It is a schematic diagram of the second structure and method of preventing the exhaust system from being blocked by substrate fragments according to the present invention.

[0019] Figure 8a Schematic diagram of a fourth embodiment of an exhaust system of the present invention.

[0020] Figure 8b Schematic diagram of the fifth embodiment of the exhaust system of the present invention.

[0021] Figure 9a , 9b It is a schematic diagram of the structure of the third type of exhaust system of the present invention to prevent blockage by substrate fragments. DETAILED DESCRIPTION

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

[0023] like Figure 2 As shown, the present invention provides a MOCVD reactor, the overall structure of the reactor is Figure 1The exhaust system is basically the same as shown, and the main difference lies in the improvement of the exhaust system structure. The exhaust system includes a flow limiting ring, the interior of the flow limiting ring is hollow to form an exhaust chamber 132, and the exhaust chamber 132 is surrounded by a top plate 133a, an exhaust chamber side wall 133b, an exhaust chamber bottom wall 133c, and a part of the base side wall 16. An airflow opening 130 is provided on the exhaust chamber side wall 133b, so that the airflow after the reaction can flow into the exhaust chamber 132 laterally through the airflow opening 130, and at the same time, the pollutants falling from the top can slide through the top plate 133a to the storage chamber 131 below the exhaust chamber 132. In the present invention, the space below the exhaust chamber and above the chamber bottom wall 110, from the base side wall 16 to the inner wall of the reaction chamber, all constitute the storage chamber 131, so the same volume of solid pollutants can be distributed in a larger range, and the accumulation and rising speed of pollutants is slower than that of the prior art. In addition, before the pollutant accumulation height reaches the exhaust chamber bottom wall 13c, a horizontal gas diffusion space is formed below the exhaust chamber bottom wall 133c. At this time, part of the reacted gas flow enters the gas flow opening 130 through the path 18, and the rest is separated into two branch gas flows 19a and 19b, wherein the branch gas flow 19a will decelerate after colliding with the surrounding solids multiple times in the gas diffusion space, and will not generate a high-speed upward gas flow; since the branch gas flow 19b is diverted by 19a, the gas flow rate and flow rate are greatly reduced, so it is impossible to push the pollutant particles to the height above the base 14. The exhaust chamber 132 constitutes an annular gas diffusion chamber, and multiple exhaust pipes 17' are arranged at multiple different azimuth positions to pass through the storage chamber 131 and support the exhaust chamber 132, and finally the gas is extracted out of the reaction chamber through the exhaust pipe. In the above embodiments, the exhaust cavity 132 is shared with the inner side wall and part of the side wall of the base, and the outer side wall of the exhaust cavity can also be shared with the side wall of the cavity body, both of which belong to the embodiments of the present invention. Under these embodiments, there is no need to set up an additional exhaust pipe 17' to support and fix the exhaust cavity 132, and the exhaust pipe connected to the air pump is directly set on the outer side wall shared with the exhaust cavity 132. An additional support structure can also be set, such as a support rod extending upward from the bottom wall of the cavity to support the above-mentioned exhaust cavity 132, and the exhaust pipe 17 is only connected to the exhaust cavity as an airflow passage, and does not need to provide a stable support.

[0024] like Figure 3 The second embodiment of the MOCVD reactor of the present invention is shown. Figure 2The embodiments shown are basically the same, the main difference is that the exhaust chamber 132 is located between the base side wall 16 and the cavity side wall 100, and is independently suspended above the storage chamber 131. The exhaust chamber 132 includes two top plates 134a extending downwardly and obliquely toward the radial inner side and outer side, two exhaust chamber side walls 134b located below each top plate 134a, openings 130 are respectively provided on the two side walls, and a bottom wall 134c. The exhaust chamber top plate can also be only one piece, which is inclined downward in one direction (such as the outer side), but this result will cause the airflow to have different flow rates when passing through the inner side wall and the outer side wall of the exhaust chamber, but it can also achieve the purpose of the present invention. Under this exhaust system structure, the main airflow enters the exhaust chamber 132 through the path shown in 18a and 18b, and the remaining airflow will diffuse in the lateral diffusion space below the bottom wall 134c along the path shown in 19a1 and 19a2 in the figure, and finally the flow rate is greatly reduced after the multi-path airflow collides and mixes with each other. Since the air flow passages between the two exhaust chamber side walls 134b and the base side wall 16 and the reaction chamber wall 110 are narrow, large amounts of Figure 2 The upward airflow along the side wall (16, 100) shown in 19b can ultimately prevent the airflow from flowing back to the upper base at high speed, thereby ensuring the stable and reliable growth quality of the substrate.

[0025] like Figure 4 The third embodiment of the MOCVD reactor of the present invention is shown. Figure 2 The embodiments shown are basically the same, with the main difference being that the opening 130" of the exhaust chamber 132 is disposed on the bottom wall 134c of the exhaust chamber. At this time, in addition to the main airflows 18a and 18b bypassing the exhaust chamber 132 from the inside and outside 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 to form a counterattack, greatly reducing the airflow velocity, and ultimately preventing the airflow from flowing back to the upper base position at high speed. In addition to being disposed below the exhaust chamber 132, the exhaust duct 17 can also be disposed on the outer wall of the exhaust chamber 132, extending outward through the cavity side wall 100, and ultimately achieving gas discharge from the reaction chamber.

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

[0027] Figure 5Another variant embodiment of the present invention is shown, in which 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 bottom opening 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 bottom opening 130” 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, and the pollutants 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 quickly and completely, 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 that of the air flow cross-section 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 refluxed in the lower Z region cannot break through the high-density and high-speed air curtain formed by the Y region, avoiding the reflux of pollutants. The relatively narrow channel in the above-mentioned Y region forms a constraint on the air flow, and the air flow turning twice in the Z region and entering the exhaust cavity upward 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 multiple embodiments provided by the present invention realize that the exhaust chamber, the transverse gas diffusion space, and the storage chamber are stacked in sequence, wherein the gas diffusion chamber and the storage chamber have a large transverse width, so that the accumulation height of the deposited pollutants increases slowly, and the wider transverse gas diffusion space allows the remaining branch airflows (19a, 19a1, 19a2) except the main airflow to diffuse and impact each other in the transverse diffusion space, and finally reduce the speed of these airflows to a sufficiently low level so that these airflows cannot push the particulate pollutants in the storage chamber below to the height of the upper base.

[0029] The present invention also provides another embodiment, such as Figure 8a As shown, a limiting ring 233 is provided at the upper part of the exhaust area. The contour of the limiting ring 233 is the same as the outer contour of the exhaust cavity described in the other embodiments above, and also includes an inclined top plate 233a, a vertical side wall 233b and a bottom wall 233c, but no opening for exhaust is provided on the side wall 233b or the bottom wall 233c. Instead, an opening is provided on the cavity side wall 100 below the limiting ring, and then a gas diffusion ring 25 is provided outside the cavity side wall 100. The gas diffusion ring 25 is connected to the air pump through a plurality of exhaust pipes 17. Under this exhaust structure, the airflow passing through the large cross-sectional area (spacing D0) above the limiting ring 233 is restricted to the airflow of the small cross-sectional area (spacing D1c), and finally the airflow turns and diffuses through the airflow lateral diffusion channel of the larger cross-sectional area (spacing D2) to the opening 230 located on the cavity side wall. Due to the great reduction in the cross-sectional area of ​​the airflow, the airflow will be concentrated between the limiting ring side wall 233b and the base side wall 16 to form a high-speed airflow, and finally decelerate again in the lateral gas diffusion space below the limiting ring, so that the pollutant particles falling from the top are deposited at the bottom of the storage cavity 131. In addition to part of the laterally diffused airflow being able to smoothly pass through the opening 230 to enter the gas diffusion ring 25, part of the airflow will hit the cavity side wall 100 around the opening 230, and then rebound to form a vortex 19c, but the flow rate of the vortex 19c is significantly lower than the aforementioned high-speed airflow, so the reverse vortex 19c cannot pass through the dense and high-speed downward airflow to push the pollutants to the surface of the upper substrate. Therefore, the embodiment shown in Figure 8 can also achieve a large amount of accumulation of pollutants in the storage cavity, improve the maintenance cycle of the cavity, and prevent the particles from being returned to the upper substrate by the airflow, which belongs to the embodiment of the present invention. Figure 8b Another variant embodiment of the present invention is shown, and its basic structure is similar to Figure 8a The embodiment shown is the same, the main difference is that the gas diffusion ring 25' is arranged inside the cavity side wall 100, and the exhaust pipe 17 is also correspondingly arranged inside the cavity side wall 100. Figure 8bIn the embodiment shown, the downward airflow diffuses laterally for a short distance after turning to reach the gas diffusion ring 25', enters the airflow diffusion ring through the opening 230' on the gas diffusion ring 25', and is then discharged from the cavity by the exhaust pipe 17 below. This embodiment can still maintain three different airflow cross-sectional area ratios, so it can obtain the same Figure 8a The technical effects of the embodiments shown are basically the same. In addition to being arranged on the cavity side wall 100 as mentioned above, the flow limiting ring of the present invention can also be arranged on the base side wall 16, or include two opposite limiting ring parts, which are arranged on the cavity side wall 100 and the base side wall 16 respectively, to form an airflow constraint structure together, so that after the airflow is constrained to a channel with a narrower airflow cross section, it turns below the constraint ring, and then diffuses laterally in the lateral diffusion space, and finally reaches the airflow diffusion ring, wherein the space below the lateral diffusion space is where pollutants accumulate.

[0030] The present invention is applied to Figure 1 The prior art MOCVD reaction chamber shown in the figure has certain technical problems. The substrate revolving at high speed on the base will be warped due to heat deformation and other reasons, and then thrown out of the base by centrifugal force. After hitting the shielding tube 62, multiple fragments are formed and fall into the exhaust area below. The size of the substrate is larger than the size of the airflow channel in the exhaust area. In addition to the fact that some substrates fall in the vertical direction and can directly pass through the narrow airflow channel and fall into the storage chamber 131 below, there is a high probability that the substrate fragments will be stuck laterally between the inclined top plate (133a, 134a) and the base side wall 16 or the cavity side wall 100. These stuck substrates will cause serious uneven airflow distribution and are difficult to remove. For this reason, the inventors have proposed further improvement schemes, such as Figure 6 The figure shows 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 lifted up separately, so that one end of the substrate fragment S is greatly raised until the fragment S is basically in a vertical state and then slides down to the storage chamber below. Figure 7 The figure shows a partial enlarged view of the exhaust area of ​​the present invention. A plurality of corresponding recessed parts are arranged in the area corresponding to the inclined top plate on the inner side of the cavity side wall 100. The recessed parts are connected to the inner surface of the cavity side wall 100 through two upper and lower transition steps 105. An arc-shaped baffle 101 is arranged in each recessed part. The baffle 101 is conformal with the inner surface of the cavity side wall to form a continuous airflow channel. When it is detected that the substrate fragment S is stuck between the baffle and the inclined top plate of the exhaust chamber during the reaction process, the driving rod 103 can be retreated a certain distance to make one end of the substrate fragment slide down, and finally the entire substrate fragment falls into the storage chamber below, or one end of the substrate fragment slides to the transition step 105 below, and then the baffle 101 can push the fragment into the reaction chamber when it returns to the initial position forward, so that the substrate fragment falls into the storage chamber below.

[0031] The inclined top plate of the exhaust chamber may not be fixedly connected to the side wall and bottom wall of the exhaust chamber below, but may be supported by a sliding support device, and then the inclined top plate is rotated along the rotating axis 24 in the center of the reaction chamber by a driving device such as a gear. When substrate fragments are stuck between the exhaust chamber top plate 133a and the chamber side wall 100, the first end contacts the inclined top plate, and the second end contacts the base side wall 16 or the chamber side wall 100. When the inclined top plate continues to rotate, the substrate fragments will be driven by the friction force to move the first end in a circumferential direction, and finally the posture of the substrate fragments will change, so that when the plane of the substrate fragments is close to a vertical state, it can slide into the storage chamber below, and finally the purpose of preventing the substrate fragments from being stuck in the exhaust area is achieved. In order to prevent the posture of the substrate fragments from maintaining a balanced state and continuously sliding on the inclined top plate without rotating, grooves or ridges extending in the up-and-down directions may be provided on the upper surface of the inclined constraint ring top plate to form 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 cavity 133 in the embodiment shown in FIG. Figure 9b for Figure 9a A horizontal cross-section of the top plate 133a in the middle. The falling substrate fragments will be closely contacted by the inclined surface of the constraint ring top plate 133a and stuck in the initial position. When the inclined top plate 133a rotates, the convex ridge 139 adjacent to the contact point of the substrate fragments will slightly lift the substrate fragments upward, and no longer be in close contact with the inclined top plate. At the same time, the convex ridge can also force the first end of the substrate fragment to rotate with the inclined top plate. Both movements can make the substrate fragments break the original equilibrium posture. After multiple cycles, the posture of the substrate fragments is adjusted to a nearly vertical state, and finally the lateral friction force at both ends of the substrate fragments is insufficient to support the substrate fragments and fall vertically downward. In addition, the convex ridge may also directly crush the substrate fragments further, so that the substrate fragments break into smaller fragments and then slide into the storage chamber below. The use of the rotating inclined top plate proposed by the present invention does not affect the airflow distribution, so it can be continued during the process, and there is no need to wait until the process is finished to remedy it, so the process effect can be maintained for a long time. Stability.

[0032] The present invention provides a flow limiting ring located in the upper space of the exhaust area, which compresses 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, so that a high-speed and dense airflow is formed around the side wall of the flow limiting ring. After reaching the bottom of the flow limiting ring, the airflow diffuses in a larger lateral space, so that the airflow speed is reduced again, and reaches an opening set on the bottom wall of the flow limiting ring, the side wall of the cavity, or the side wall of the base. Then, it is converged by the hollow flow limiting ring downstream of the opening, the side wall of the cavity, or the gas diffusion ring on the side wall of the base, and then discharged from the cavity through the exhaust pipe. The hollow flow limiting ring that is connected to the outside world through the exhaust pipe constitutes an exhaust cavity, and can also be as Figure 8a , 8bThe current limiting ring shown is hollow but not connected to the outside and is only used as a current limiting ring. The above-mentioned different deformations all constitute deformation embodiments of the present invention.

[0033] The present invention can be used in the aforementioned MOCVD equipment, and can also be used in other chemical vapor deposition equipment that may generate a large amount of pollutants, such as PECVD for depositing SiO2 and SiN, or other thin film deposition processes that use a precursor gas (precursor) reactor containing organic groups. In such reactors, a large amount of pollutant deposition may be formed downstream of the reaction area, and the structural design of the present 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 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 combinations thereof.

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

[0036] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as limiting the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention. After reading the above content, it will be obvious for those skilled in the art to make various modifications and substitutions to the present invention. Therefore, the scope of protection of the present invention should be defined by the attached claims.

Claims

1. A chemical vapor deposition device, comprising: A reaction chamber, including chamber side walls and a bottom wall; A base is located in the reaction chamber, the base includes a base side wall, and an exhaust area is included between the base side wall and the chamber side wall, and the airflow from above the base passes through the exhaust area and is discharged from the reaction chamber; characterized in that the device also includes: A confinement ring is located in the exhaust area and surrounds the side wall of the base, the confinement ring comprises a top plate, a side wall and a bottom wall, and a storage cavity is provided between the bottom wall of the confinement ring and the bottom wall of the cavity; The top plate of the confinement ring extends downwardly in an inclined manner, so that pollutants above the top plate of the confinement ring can slide downward; The bottom space of the storage cavity is used for accumulating pollutants, and the top space is used for lateral diffusion of airflow, so that after the airflow passes through the side wall of the confinement ring, at least part of the airflow flows laterally in the lateral diffusion space.

2. The chemical vapor deposition apparatus according to claim 1, characterized in that: The confinement ring is hollow, and the side wall or the bottom wall includes at least one opening for allowing the airflow to pass through the opening and enter the confinement ring.

3. The chemical vapor deposition apparatus according to claim 2, characterized in that: The inner side wall or the outer side wall of the confinement ring is fixed to the base side wall or the cavity side wall.

4. The chemical vapor deposition apparatus according to claim 2, characterized in that: The restraining ring comprises an inner side wall and an outer side wall which respectively support two top plates inclined downward.

5. The chemical vapor deposition apparatus according to claim 2, characterized in that: The invention also comprises at least one exhaust pipe connected between the confinement ring and the bottom wall or the side wall of the reaction chamber to exhaust the gas in the confinement ring.

6. The chemical vapor deposition apparatus according to claim 1, characterized in that: The radial width of the confinement ring is set so that the cross-sectional area of ​​the airflow passing through the top of the confinement ring is larger than 1.5 times the cross-sectional area of ​​the airflow passing through the side wall of the confinement ring.

7. The chemical vapor deposition apparatus according to claim 1, characterized in that: Above the exhaust area in the reaction chamber, there is a shielding tube surrounding the reaction space above the base, and a cooling liquid channel is arranged in the shielding tube.

8. The chemical vapor deposition apparatus according to claim 1, characterized in that: The inner side of the side wall of the base includes a heater located below the base, and also includes a rotating shaft connected to the center of the base or a rotating cylinder connected to the outer edge of the base.

9. The chemical vapor deposition apparatus according to claim 1, characterized in that: The top plate of the constraint ring and the side wall of the constraint ring can move relative to each other, and the relative movement includes the top plate of the constraint ring moving up and down or the top plate of the constraint ring moving in a circle.

10. The chemical vapor deposition apparatus according to claim 9, characterized in that: The top plate of the confinement ring is provided with ridges extending in the up-down direction, so that the size or position of the substrate fragments can be changed when the top of the confinement ring moves in a circle.

11. The chemical vapor deposition apparatus according to claim 1, wherein: The inner side surface of the chamber side wall and the area corresponding to the confinement ring top plate include a plurality of arc-shaped recessed portions, each of which includes a baffle, the front side of the baffle is conformal to the inner wall of the reaction chamber, and the back side of the baffle includes a driving rod so that the baffle can reciprocate toward the center of the reaction chamber.

12. The chemical vapor deposition apparatus according to claim 1, wherein: There is a high-speed airflow channel between the inner wall of the confinement ring and the side wall of the base and / or between the outer wall of the confinement ring and the side wall of the cavity; the cross-sectional area of ​​the airflow channel above the confinement ring is greater than or equal to 2 times, and less than 10 times, the cross-sectional area of ​​the high-speed airflow channel.

13. The chemical vapor deposition apparatus according to claim 1, wherein: It also includes a gas diffusion ring, and a side wall of the gas diffusion ring includes an opening, and the opening is connected to the lateral diffusion space in the storage cavity, so that the gas flow passes through the lateral diffusion space and then is discharged from the reaction cavity through the gas diffusion ring.

14. The chemical vapor deposition apparatus according to claim 13, characterized in that: The gas diffusion ring is connected to the bottom through at least one exhaust pipe.

15. The chemical vapor deposition apparatus according to claim 13, characterized in that: The diffusion ring is connected to the cavity sidewall or the susceptor sidewall and is located below the confinement ring.

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