SiC epitaxial vertical reaction chamber structure

Abstract

The invention relates to the technical field of SiC epitaxy, and mainly relates to a SiC epitaxy vertical reaction chamber structure, comprising: a liner tube having a shape of a cylinder structure with two open ends, one end used for allowing process gas to enter, and the other end used for allowing process gas to flow out; the process pipe is of a sleeve structure with an opening in only one end, the liner pipe is sleeved with the opening downwards, and an interlayer allowing process gas to pass through is formed between the process pipe and the liner pipe; the wafer boat frame is arranged in the liner tube and is used for bearing multiple layers of wafers; the gas supply assembly is used for conveying process gas to the liner tube; and the heating assembly is arranged outside the process pipe and is used for heating the wafer boat rack. The wafer boat rack capable of bearing multiple layers of wafers is arranged in the liner tube, the gas supply assembly introduces the process gas into the liner tube, the heating assembly heats the liner tube, SiC epitaxy can be carried out on the multiple layers of wafers, and then the process gas smoothly flows out from an interlayer between the liner tube and the process tube. The structure can significantly improve the production efficiency of SiC epitaxy and reduce the epitaxy cost.

Description

Technical Field

[0001] The present application relates to the technical field of SiC epitaxy, and mainly to a SiC epitaxy vertical reaction chamber structure. Background Art

[0002] The SiC (silicon carbide) reaction growth chamber is the core component of the entire epitaxial furnace equipment. The uniformity, growth rate and defect density of SiC epitaxial growth are closely related to it. At present, the epitaxial furnace reaction chamber structures on the market are mainly divided into two types: horizontal and vertical. Figure 1 , Figure 1 This is a schematic diagram of the structure of an existing horizontal hot wall reaction chamber model, in which the reaction chamber structure is monolithic, the wafer is placed on a graphite base, and ultra-high temperature is achieved by induction heating. At the same time, the graphite parts around the reaction chamber are heated to form a hot wall to maintain the temperature in the reaction chamber and the uniformity of the temperature field in the substrate placement area; the growth source gas enters from one end and exits from the other end to achieve horizontal laminar flow, and the substrate is rotated at a low speed by air floating to offset the growth unevenness caused by the exhaustion of the reaction source along the way. The reaction chamber structure is relatively simple and can perform ultra-fast epitaxial growth. Figure 2 , Figure 2 This is a structural schematic diagram of an existing vertical hot wall reaction chamber model. The reaction chamber structure is also monolithic. The wafer is placed on a graphite base and uses zoned resistance heating. The bottom heating part acts on the wafer tray area, and the upper heating part acts on the upper and middle part of the reaction chamber wall. This temperature field design can achieve good temperature uniformity in the wafer area and achieve better growth uniformity control. In terms of flow field, the reactant gas source is sprayed vertically over a long distance combined with high-speed rotation of the wafer carrier to accelerate the growth rate and improve uniformity.

[0003] At present, these two epitaxial growth methods are only suitable for single-wafer growth. Some patents have been proposed at home and abroad to optimize the reaction chamber structure, but they can only be barely expanded to two or three or four wafers. The production efficiency is still restricted and cannot meet the current market's growing demand for cost control of SiC power devices. Therefore, it is necessary to develop a reactive structure that can simultaneously epitaxially grow multiple wafers to improve efficiency. Therefore, the existing technology needs to be improved and developed. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the purpose of the present application is to provide a SiC epitaxial vertical reaction chamber structure, aiming to solve the problem that the existing reactive structures are mostly monolithic, resulting in low epitaxial efficiency.

[0005] The technical solution of this application is as follows: The present application provides a SiC epitaxial vertical reaction chamber structure, which includes: The liner is a cylindrical structure with two ends open, one end for process gas to enter and the other end for process gas to flow out; The process pipe is in the shape of a sleeve structure with only one end open, and the opening is downwardly sleeved outside the liner, and a sandwich is formed between the process pipe and the liner for the process gas to pass through; A wafer boat, disposed in the liner tube, for carrying multiple layers of wafers; a gas supply assembly for delivering process gas to the liner; A heating component is arranged outside the process tube and is used for heating the wafer boat.

[0006] The present application arranges a wafer boat capable of carrying multiple layers of wafers in a liner tube, a gas supply assembly introduces process gas into the liner tube, and a heating assembly heats the liner tube to ensure the epitaxial temperature of the wafer boat therein, so that SiC epitaxy can be performed on the multiple layers of wafers, and the process gas after epitaxy flows out smoothly from the interlayer between the liner tube and the process tube.

[0007] Furthermore, the wafer boat comprises: The bottom plate is in the shape of a disc structure; The top plate is in the shape of a disc structure and is arranged above the bottom plate; A column, wherein a plurality of wafer placement grooves are evenly formed on the inner side of the column along the extension direction, the bottom end of the column is detachably connected to the bottom plate, and the top end of the column is detachably connected to the top plate; Through holes for process gas to pass through are provided in the middle of the bottom plate and the top plate.

[0008] Furthermore, the SiC epitaxial vertical reaction chamber structure also includes a rotating assembly for driving the wafer boat to rotate along the circumference of the base plate.

[0009] Furthermore, the wafer placement groove includes a placement surface for placing the wafer, a first inclined surface inclined downward is provided at one end of the placement surface close to the middle of the wafer, and a second inclined surface inclined upward is provided at one end of the placement surface away from the middle of the wafer, and the top end of the second inclined surface is used to abut against the bottom edge of the wafer.

[0010] Furthermore, the SiC epitaxial vertical reaction chamber structure further includes: The heat insulation layer is arranged below the wafer boat frame, and the heat insulation layer comprises a plurality of heat insulation sheets which are stacked at intervals, and a through hole for the process gas to pass through is opened in the middle of the heat insulation sheet.

[0011] Furthermore, the heating component comprises: A top heater, which is in the shape of a flat plate structure and is arranged on the top of the process tube; The middle heater, in a cylindrical structure, is sleeved outside the process tube and corresponds to the position of the wafer boat holder. The lower heater, in a cylindrical structure, is sleeved outside the process tube and is arranged below the middle heater.

[0012] Furthermore, the SiC epitaxial vertical reaction chamber structure further includes: The heat insulation layer is arranged outside the heating component and covers the side and top of the process tube.

[0013] Furthermore, the heat insulation layer includes: The upper heat insulation layer covers the top of the process tube and corresponds to the position of the top heater. The middle heat insulation layer, in a cylindrical structure, is sleeved outside the process tube and corresponds to the position of the middle heater. The lower heat insulation layer, in a cylindrical structure, is sleeved outside the process tube and corresponds to the position of the lower heater. The bottom heat insulation layer, in a cylindrical structure, is sleeved outside the process tube and covers the remaining part of the side of the process tube. Through holes for installing an infrared pyrometer are provided in the middle of the upper heat insulation layer and on the sides of the middle heat insulation layer and the lower heat insulation layer.

[0014] Furthermore, the height of each layer of the wafer placement groove is 4.75 mm, and the gap between the wafer placement grooves is 2.25 mm. The surface of the wafer boat holder is coated with a SiC coating with a thickness of 100 μm. The surfaces of the liner tube and the process tube are coated with a SiC coating with a thickness of 100 μm.

[0015] Furthermore, the height of each layer of the heat insulation sheet is 4 mm, and the thickness of the heat insulation sheet is 2 mm. The surface of the heat insulation sheet is coated with a SiC coating with a thickness of 100 μm.

[0016] Beneficial effects: In this application, a wafer boat holder capable of carrying multiple layers of wafers is placed in a cylindrical liner tube, and process gas is introduced into the liner tube through a gas supply component. After being heated by a heating component, epitaxial growth of SiC can be carried out on multiple layers of wafers. Moreover, the process gas after epitaxy can smoothly flow out from the interlayer between the liner tube and the process tube after reaching the top of the process tube through the liner tube, avoiding affecting the epitaxial process. Through the epitaxial vertical reaction structure provided in this application, it is beneficial to simultaneously epitaxially grow SiC on multiple layers of wafers, significantly improving production efficiency and reducing epitaxial costs. Description of the Drawings

[0017] Figure 1It is a schematic structural diagram of an existing horizontal hot-wall reaction chamber model.

[0018] Figure 2 It is a schematic structural diagram of an existing vertical hot-wall reaction chamber model.

[0019] Figure 3 It is one of the schematic structural diagrams of the SiC epitaxial vertical reaction chamber structure of the present application.

[0020] Figure 4 It is the second schematic structural diagram of the SiC epitaxial vertical reaction chamber structure of the present application.

[0021] Figure 5 It is the third schematic structural diagram of the SiC epitaxial vertical reaction chamber structure of the present application.

[0022] Figure 6 It is a top view of the wafer boat rack of the SiC epitaxial vertical reaction chamber structure of the present application.

[0023] Figure 7 It is a schematic structural diagram of the wafer placement groove of the SiC epitaxial vertical reaction chamber structure of the present application.

[0024] Figure 8 It is a schematic structural diagram of the top heater of the SiC epitaxial vertical reaction chamber structure of the present application.

[0025] Figure 9 It is a schematic structural diagram of the middle heater of the SiC epitaxial vertical reaction chamber structure of the present application.

[0026] Figure 10 It is a schematic structural diagram of the lower heater of the SiC epitaxial vertical reaction chamber structure of the present application.

[0027] Label description: 100, liner tube; 200, process tube; 300, wafer boat rack; 310, bottom plate; 320, top plate; 330, column; 331, wafer placement groove; 332, placement surface; 333, first inclined surface; 334, second inclined surface; 400, heating assembly; 410, top heater; 420, middle heater; 430, lower heater; 500, heat insulation layer; 510, heat insulation sheet; 600, thermal insulation layer; 610, upper thermal insulation layer; 620, middle thermal insulation layer; 630, lower thermal insulation layer; 640, bottom thermal insulation layer. Detailed implementation manners

[0028] The present application provides a SiC epitaxial vertical reaction chamber structure. To make the purpose, technical solution and effects of the present application clearer and more definite, the present application is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0029] The technical solution of the present application is as follows: Referring to Figures 3 - 10 , the present application provides a SiC epitaxial vertical reaction chamber structure, which includes: A liner 100, having a cylindrical structure with both ends open, one end for allowing process gas to enter and the other end for allowing process gas to flow out; A process tube 200, having a sleeve structure with only one end open, the open end is sleeved outside the liner 100 downward, and a sandwich layer for allowing process gas to pass through is formed between the process tube 200 and the liner 100; A wafer boat rack 300, disposed inside the liner 100, for carrying multiple layers of wafers; A gas supply assembly (not shown in the figure), for delivering process gas to the liner 100; A heating assembly 400, disposed outside the process tube 200, for heating the wafer boat rack 300.

[0030] Referring to Figure 4 , in the present application, the wafer boat rack 300 capable of carrying multiple layers of wafers is placed inside the cylindrical liner 100, process gas is introduced into the liner 100 through the gas supply assembly, and SiC can be epitaxially grown on the multiple layers of wafers after being heated by the heating assembly 400. Moreover, the process gas after epitaxy can smoothly flow out from the sandwich layer between the liner 100 and the process tube 200 after reaching the top of the process tube 200 through the liner 100, avoiding affecting the epitaxial process. Through the epitaxial vertical reaction chamber structure provided by the present application, it is beneficial to simultaneously epitaxially grow SiC on multiple layers of wafers, significantly improving the production efficiency and reducing the epitaxial cost.

[0031] Among them, the liner 100 and the process tube 200 can be processed from semiconductor-grade graphite material, and the surface can be coated with a SiC coating, and the thickness of the SiC coating can be set to 100 μm. By coating with the SiC coating material, it can better increase the surface purity and density, and prevent metal diffusion contamination at high temperatures and particle contamination under high thermal shock.

[0032] Among them, the process gas includes a carbon source gas, a silicon source gas, a doping gas, and a carrier gas. The carbon source gas can be ethylene (C2H4) with a purity of 6N, a pressure of 0.2 - 0.4 Mpa, and a maximum flow rate of 500 sccm; the silicon source gas can be trichlorosilane (SiHCl3) with a purity of 6N, a pressure of 0.2 Mpa, and a maximum flow rate of 500 sccm; the doping gas includes nitrogen (N2) with a purity of 6N, a pressure of 0.2 - 0.4 Mpa, and a maximum flow rate of 5 SLM; the carrier gas includes hydrogen (H2) and argon (Ar). The purity of hydrogen is 9N, the pressure is 0.2 - 0.4 Mpa, and the maximum flow rate is 110 SLM; the purity of argon is 5N, the pressure is 0.2 - 0.4 Mpa, and the maximum flow rate is 15 SLM. Specifically, by setting corresponding gas supply pipelines and a gas premixing chamber structure in the gas supply assembly, each gas component can be premixed to form the process gas, and then transported into the liner 100. Among them, the settings of the gas supply pipeline and the gas premixing chamber can refer to the prior art and will not be elaborated here.

[0033] Referring to Figure 5 and Figure 6 , in a specific embodiment of the present application, the wafer boat rack 300 includes: A bottom plate 310 with a disk structure; A top plate 320 with a disk structure, arranged above the bottom plate 310; Columns 330, on the inner side of the columns 330, a plurality of wafer placement grooves 331 are evenly formed along the extending direction. The bottom end of the columns 330 is detachably connected to the bottom plate 310, and the top end of the columns 330 is detachably connected to the top plate 320; Through holes for the process gas to pass through are provided in the middle of the bottom plate 310 and the top plate 320.

[0034] In the present application, by setting a plurality of wafer placement grooves 331, it is convenient to stack and air a plurality of wafers, which is beneficial to epitaxially grow SiC simultaneously. By providing through holes in the bottom plate 310 and the top plate 320, it is convenient for the process gas to enter and directly act on the wafers. According to the entering direction of the process gas, the process gas scatters after acting on the first layer of wafers and continues to flow to the subsequent wafers for epitaxy, which is beneficial to realizing the simultaneous epitaxial growth of SiC on multiple layers of wafers.

[0035] Among them, the orientation of the wafer placement grooves 331 can be set towards the middle of the wafers. A plurality of columns 330 can be provided, as long as it is ensured that the wafers can be placed and the wafers can be maintained stable, which is convenient for epitaxially growing uniform SiC on the wafers. Preferably, referring to Figure 5 and Figure 6, the number of the columns 330 of the present application is set to 3. Setting too many columns 330 will affect the gas flow effect. Setting 3 columns can ensure the stability of multiple layers of wafers and the flow of process gas at the same time. Among them, if 3 or more columns 330 are evenly distributed along the circumferential direction of the bottom plate 310, it will cause the limited size of the wafers that can be directly placed, or disassembly operations are required during placement. Specifically, after setting one column 330, the other two columns 330 can be symmetrically arranged with its orientation as the axis of symmetry, and the angle is greater than 90°, generally not greater than 100°, which is convenient for directly placing the wafers of corresponding sizes into the wafer placement grooves 331, and is also beneficial to maintaining the stability of the wafers during the subsequent epitaxial process.

[0036] Among them, the shape of the through hole provided in the middle of the bottom plate 310 and the top plate 320 is preferably circular. In this way, when the air flow enters the wafer boat rack 300, it is blocked by the wafers arranged first. The air flow with an overall circular cross-section is easy to spread to the circumferential direction of the wafers, improving the uniformity of the air flow flowing through the circumferential direction of the wafer boat rack 300, which is beneficial to improving the epitaxial uniformity of SiC.

[0037] Furthermore, the layer height of each layer of wafer placement grooves 331 can be set to 4.75 mm, and the gap between the wafer placement grooves 331 can be set to 2.25 mm. Among them, the wafer placement grooves 331 can be set to 10 - 50 layers according to the needs of the epitaxial quantity. The material of the wafer boat rack 300 can be processed from semiconductor-grade graphite material, and the surface can be coated with a SiC coating, and the thickness of the SiC coating can be set to 100 μm.

[0038] Refer to Figure 5 , specifically, the SiC epitaxial vertical reaction chamber structure of the present application can be placed on the base of the epitaxial furnace. A gas chamber can be provided in the base, and the gas chamber is provided with through holes communicating with the interlayer between the liner 100 and the process tube 200. The process gas after epitaxy can be discharged through the gas chamber.

[0039] Refer to Figure 4 ( Figure 4 The straight trajectory arrows in [ ] indicate the flow direction of the process gas at the two open ends of the liner 100, and the elliptical trajectory arrows indicate that the wafer boat rack 300 can rotate), in a specific embodiment of the present application, the SiC epitaxial vertical reaction chamber structure further includes a rotating assembly (not shown in the figure) for driving the wafer boat rack 300 to rotate along the circumferential direction of the bottom plate 310.

[0040] In this application, since the process gas will be blocked by the first layer of wafers and then spread out and act on the subsequent wafers after entering, when the rotation assembly drives the wafer boat holder 300 to rotate circumferentially along the bottom plate 310, the upright column 330 and the wafer placement groove 331 can guide and press part of the process gas flowing from bottom to top into the gap between adjacent subsequent wafers through rotation, improving the uniformity of the airflow effect. At the same time, in cooperation with the process gas continuously flowing circumferentially in the wafer boat holder 300, the flow effect of the gap between wafers can be ensured. Through the dynamic rotation of the wafer boat holder 300 in this application, the asymmetry of the thermal field and the flow field can be effectively reduced, the uniformity of epitaxy can be improved, which is beneficial to ensuring the uniformity of subsequent wafer epitaxial growth.

[0041] Among them, by setting corresponding dimensions, the distance between the outer contour of the wafer boat holder 300 and the inner wall of the liner 100 can be controlled at a small scale, reducing the tendency of the process gas to flow directly out from the gap between the upright column 330 and the liner 100, which is convenient for maintaining the airflow to enter from the through holes provided in the bottom plate 310, flow through the wafer boat holder 300 from bottom to top, act on the multiple layers of wafers carried, and then flow out from the through holes provided in the top plate 320, which is beneficial to ensuring the simultaneous epitaxy of multiple layers of wafers.

[0042] Among them, generally, the same rotation direction is maintained during the epitaxy process to avoid disturbing the flow of the process gas due to reverse rotation.

[0043] Specifically, the rotation assembly may include a circular flange, a motor, and a synchronous belt. The wafer boat holder 300 can be installed on the circular flange, and the circular flange is driven by the motor and the synchronous belt to drive the wafer boat holder 300 to rotate.

[0044] Refer to Figure 7 , in a specific embodiment of this application, the wafer placement groove 331 includes a placement surface 332 for placing the wafer. One end of the placement surface 332 close to the middle of the wafer is provided with a first inclined surface 333 inclined downward, and one end of the placement surface 332 far from the middle of the wafer is provided with a second inclined surface 334 inclined upward. The top end of the second inclined surface 334 is used to abut against the bottom edge of the wafer. Among them, the top surface of the wafer does not contact the wafer placement groove 331.

[0045] In this application, by abutting the top end of the second inclined surface 334 against the bottom edge of the wafer, the wafer can be lifted off the ground, ensuring the coverage of epitaxial SiC on the wafer. Moreover, there are gaps formed between the two sides of the lifted-off wafer and the wafer placement groove 331. Through the rotation of the wafer boat holder 300, the process gas flowing into the wafer can also smoothly pass through these gaps and perform epitaxy. By setting the first inclined surface 333, the flow trend of the process gas to the gaps can be maintained, improving the flow effect of the process gas. Through the setting of this application, even after stacking multiple layers of wafers in intervals, the epitaxy effect and epitaxy quality of multiple layers of wafers can be ensured.

[0046] Referring to Figures 3 - 5 , in a specific embodiment of the present application, the SiC epitaxial vertical reaction chamber structure further includes: A heat insulation layer 500, disposed below the wafer boat holder 300. The heat insulation layer 500 includes multiple heat insulation sheets 510 stacked at intervals. A through hole for process gas to pass through is formed in the middle of the heat insulation sheet 510.

[0047] In the epitaxial process of the present application, the temperature inside the epitaxial furnace needs to reach 1600 °C. However, since the furnace door of the epitaxial furnace is disposed below the process tube 200, a sealing ring is generally provided here to ensure the airtightness of the reaction chamber structure. By providing the heat insulation layer 500, the temperature at the furnace door is ensured not to be higher than 200 °C for protection.

[0048] Among them, the heat insulation layer 500 includes multiple heat insulation sheets 510 stacked at intervals. The heat insulation sheet 510 can be made of a carbon-carbon composite material, which has high temperature resistance and good heat insulation effect. The surface of the heat insulation sheet 510 can be coated with a SiC coating, and the thickness of the SiC coating can be set to 100 μm to avoid contaminating the wafer during the epitaxial process. The thickness of the heat insulation sheet 510 can be set to 2 mm, and the interval between adjacent two heat insulation sheets 510 can be set to 2 mm. After at least 40 layers of heat insulation sheets 510 are provided through experiments, the required heat insulation effect can be ensured.

[0049] Specifically, a through hole is also formed in the middle of the heat insulation sheet 510 for the process gas to pass through. At the same time, the process gas will be gradually preheated by the heat insulation layer 500 after entering, and the gas can reach a relatively uniform initial temperature when entering the area of the wafer boat holder 300, reducing the problem of uneven epitaxial growth caused by gas temperature differences and further ensuring the epitaxial quality.

[0050] Among them, after the heat insulation layer 500 is provided, the wafer boat holder 300 and the heat insulation sheet 510 can be installed on the same circular flange for rotation. The process gas flows from bottom to top into the liner 100, passes through the through holes in the middle of multiple heat insulation sheets 510, passes through the through holes in the bottom plate 310 and then reaches the wafer boat holder 300 to perform epitaxy on the wafer carried by it. After the process gas leaves the top plate 320 of the wafer boat holder 300, it rises to the top of the process tube 200. The top of the process tube 200 is closed, and the process gas reaching here will be discharged downward from the interlayer between the liner 100 and the process tube 200.

[0051] Referring to Figures 8 - 10 , in a specific embodiment of the present application, the heating assembly 400 includes: A top heater 410, having a flat plate structure, disposed on the top of the process tube 200; The middle heater 420, which is in a cylindrical structure, is sleeved outside the process tube 200 and corresponds to the position of the wafer boat rack 300. The lower heater 430, which is in a cylindrical structure, is sleeved outside the process tube 200 and is arranged below the middle heater 420.

[0052] In this application, the middle heater 420 is in a cylindrical structure and wraps around the outside of the process tube 200. As the main heater, it generates heat to heat the entire process tube 200. The length of the constant temperature zone is mainly determined by the middle heater 420, and the length can be set to be greater than the height of the wafer boat rack 300 to ensure that the wafer undergoes epitaxy within the constant temperature zone. The top heater 410 is in a flat plate structure and is installed on the top surface of the process tube 200, mainly serving an auxiliary heating function. The lower heater 430 is in a cylindrical structure with a shorter length and is installed below the middle heater 420, serving an auxiliary heating function.

[0053] Among them, the three temperature zones formed by different heaters can be respectively subjected to closed-loop temperature control. By adopting a cascaded control loop, the fast response and stability of the heating system can be effectively ensured. Each temperature zone is relatively independently controlled, and the upper and lower temperature zones can perform temperature compensation on the middle constant temperature zone to adjust the temperature uniformity of the constant temperature zone. The temperature settings of the three temperature zones can be kept consistent to ensure the same temperature in the entire constant temperature zone.

[0054] Among them, the materials of the top heater 410, the middle heater 420, and the lower heater 430 can be high-purity graphite resistors. The traditional furnace bodies often use Kanthal nickel-chromium alloy and iron-chromium aluminum alloy, and the maximum heating temperature is 1200 °C, which cannot meet the requirements of the SiC epitaxy process. The heaters made of tungsten and graphite materials can reach a high temperature of more than 2000 °C, but the tungsten metal heater may have the risk of metal contamination. In this application, by using high-purity graphite resistors for heating, the high-purity graphite resistors have a small resistance and can generate a high current at a low voltage, fully meeting the heating requirements of 1600 °C and above.

[0055] Refer to Figure 4 , in a specific embodiment of this application, the SiC epitaxial vertical reaction chamber structure further includes: The heat insulation layer 600 is arranged outside the heating assembly 400 and covers the side and top of the process tube 200.

[0056] In this application, by setting the heat insulation layer 600 and the heat insulation sheet 510, it can be ensured that the reaction chamber maintains a constant temperature for epitaxy.

[0057] Refer to Figure 4 , in a specific embodiment of this application, the heat insulation layer 600 includes: The upper thermal insulation layer 610 covers the top of the process tube 200 and corresponds to the position of the top heater 410; The middle thermal insulation layer 620 is in the shape of a cylindrical structure, sleeved outside the process tube 200 and corresponds to the position of the middle heater 420; The lower thermal insulation layer 630 is in the shape of a cylindrical structure, sleeved outside the process tube 200 and corresponds to the position of the lower heater 430; The bottom thermal insulation layer 640 is in the shape of a cylindrical structure, sleeved outside the process tube 200 and covers the remaining part of the side of the process tube 200; Among them, the upper thermal insulation layer 610, the middle thermal insulation layer 620, the lower thermal insulation layer 630 and the bottom thermal insulation layer 640 can be sequentially arranged from top to bottom according to the orientation of the process tube 200. The corresponding position of the upper thermal insulation layer 610 and the top heater 410 means that the installation position of the upper thermal insulation layer 610 is mainly adjacent to the top heater 410, and so on. The material of the thermal insulation layer 600 can be graphite carbon felt material. By setting the thermal insulation layer 600 in four parts, it is easy to install and disassemble and ensure that the temperature in the constant temperature zone is maintained.

[0058] Specifically, through holes for installing an infrared pyrometer are opened in the middle of the upper thermal insulation layer 610, on the side of the middle thermal insulation layer 620 and on the side of the lower thermal insulation layer 630. By installing an infrared pyrometer at the corresponding through holes of the thermal insulation layer 600, it can be used to detect the temperature of the entire reaction chamber, so as to timely control the corresponding heater.

[0059] This application sets a new type of SiC epitaxial vertical reaction chamber structure, uses graphite resistance heaters in the upper, middle and lower three zones for heating, and independently controls the zones. On the premise of meeting the temperature uniformity of 1600 °C for epitaxy, the traditional graphite tray is changed to a wafer boat rack 300 to carry multiple layers of wafers. The original single-chip or double-chip reaction chamber can be expanded to a reaction chamber with up to 50 wafers, significantly improving the production efficiency and significantly reducing the epitaxy cost. The gas inlet mode is to introduce gas upward from the middle of the liner 100 and then discharge it downward around the outside of the liner 100. Through certain guidance by the column 330 and in cooperation with the rotatable wafer boat rack 300, the uniformity of the gas flow field can be greatly improved, thereby greatly improving the uniformity of epitaxial growth.

[0060] It should be understood that the application of this application is not limited to the above examples. For those of ordinary skill in the art, improvements or transformations can be made according to the above description, and all such improvements and transformations should fall within the protection scope of this application.

Claims

1. A SiC epitaxial vertical reaction chamber structure, characterized in that, Comprising: A liner (100), having a cylindrical structure with both ends open, one end for allowing process gas to enter and the other end for allowing process gas to flow out; A process tube (200), having a sleeve structure with only one end open, the open end being sleeved downward outside the liner (100), and a sandwich layer for process gas to pass through is formed between the process tube (200) and the liner (100); A wafer boat rack (300), disposed inside the liner (100) for carrying multiple layers of wafers; A gas supply assembly for delivering process gas to the liner (100); A heating assembly (400), disposed outside the process tube (200) for heating the wafer boat rack (300).

2. The SiC epitaxial vertical reaction chamber structure according to claim 1, wherein, The wafer boat rack (300) includes: A bottom plate (310), having a disc structure; A top plate (320), having a disc structure, disposed above the bottom plate (310); A column (330), on the inner side of which a plurality of wafer placement grooves (331) are uniformly formed along the extending direction, the bottom end of the column (330) is detachably connected to the bottom plate (310), and the top end of the column (330) is detachably connected to the top plate (320); Through holes for process gas to pass through are formed in the middle of the bottom plate (310) and the top plate (320).

3. The SiC epitaxial vertical reaction chamber structure according to claim 2, characterized in that, The SiC epitaxial vertical reaction chamber structure further includes a rotation assembly for driving the wafer boat rack (300) to rotate circumferentially along the bottom plate (310).

4. The SiC epitaxial vertical reaction chamber structure according to claim 2, characterized in that, The wafer placement groove (331) includes a placement surface (332) for placing a wafer, a first inclined surface (333) inclined downward is provided at one end of the placement surface (332) close to the middle of the wafer, a second inclined surface (334) inclined upward is provided at one end of the placement surface (332) away from the middle of the wafer, and the top end of the second inclined surface (334) is used to abut against the bottom edge of the wafer.

5. The SiC epitaxial vertical reaction chamber structure according to claim 1, characterized in that, The SiC epitaxial vertical reaction chamber structure further includes: A heat insulation layer (500), disposed below the wafer boat rack (300), the heat insulation layer (500) includes a plurality of heat insulation sheets (510) stacked at intervals, and through holes for process gas to pass through are formed in the middle of the heat insulation sheets (510).

6. The SiC epitaxial vertical reaction chamber structure according to claim 1, wherein, The heating assembly (400) includes: A top heater (410), having a flat plate structure, disposed at the top of the process tube (200); A middle heater (420), having a cylindrical structure, sleeved outside the process tube (200), corresponding to the position of the wafer boat rack (300); A lower heater (430), having a cylindrical structure, sleeved outside the process tube (200), disposed below the middle heater (420).

7. The SiC epitaxial vertical reaction chamber structure according to claim 6, wherein The SiC epitaxial vertical reaction chamber structure further includes: A heat preservation layer (600), disposed outside the heating assembly (400), covering the side and top of the process tube (200).

8. The SiC epitaxial vertical reaction chamber structure according to claim 7, characterized in that, The heat preservation layer (600) includes: An upper heat preservation layer (610), covering the top of the process tube (200), corresponding to the position of the top heater (410); The middle heat insulation layer (620) is in the shape of a cylindrical structure, sleeved outside the process pipe (200), and corresponding to the position of the middle heater (420); The lower heat insulation layer (630) is in the shape of a cylindrical structure, sleeved outside the process pipe (200), and corresponding to the position of the lower heater (430); The bottom heat insulation layer (640) is in the shape of a cylindrical structure, sleeved outside the process pipe (200), and covering the remaining part of the side surface of the process pipe (200); Through holes for installing an infrared pyrometer are provided in the middle of the upper heat insulation layer (610), the side surfaces of the middle heat insulation layer (620) and the lower heat insulation layer (630).

9. The SiC epitaxial vertical reaction chamber structure according to claim 2, wherein The layer height of each wafer placement groove (331) is 4.75 mm, and the gap between the wafer placement grooves (331) is 2.25 mm; The surface of the wafer boat frame (300) is coated with a SiC coating with a thickness of 100 μm; The surfaces of the liner (100) and the process pipe (200) are coated with a SiC coating with a thickness of 100 μm.

10. The SiC epitaxial vertical reaction chamber structure according to claim 5, characterized in that, The layer height of each heat insulation sheet (510) is 4 mm, and the thickness of the heat insulation sheet (510) is 2 mm; The surface of the heat insulation sheet (510) is coated with a SiC coating with a thickness of 100 μm.

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