Chemical vapor deposition device for semiconductor high-purity silicon carbide coating

Abstract

The invention relates to the technical field of chemical vapor deposition equipment, and discloses a chemical vapor deposition device for a semiconductor high-purity silicon carbide coating, the chemical vapor deposition device comprises a carrier plate movably arranged in a reaction box, the carrier plate is driven by a motor arranged in the reaction box to rotate, the outer edge of the carrier plate is fixedly provided with a plurality of slide glass devices which are distributed in a circumferential array mode, and the slide glass devices are arranged in the reaction box. The substrate carrying device comprises a base which is obliquely arranged, and the top of the base is provided with a containing groove used for containing a silicon carbide substrate. The inclined base is arranged on the carrier plate, so that a certain included angle is formed between the silicon carbide substrate on the base and the airflow direction, the airflow can be guided to sweep the surface of the silicon carbide substrate more smoothly, a tail shadow area is greatly weakened, and an airflow field is more uniform, so that the quality of a surface coating of the silicon carbide substrate is improved; and by means of the inclined angle, by-products on the surface of the substrate can be taken away by back airflow more quickly and are prevented from being adsorbed again or corroding the growth surface, and the effect of the silicon carbide coating is further improved.

Description

Technical Field

[0001] This application relates to the field of chemical vapor deposition equipment technology, and more particularly to a chemical vapor deposition apparatus for high-purity silicon carbide coatings for semiconductors. Background Technology

[0002] High-purity silicon carbide coatings mainly refer to high-purity, high-performance silicon carbide layers grown on specific substrates using chemical vapor deposition (CVD) technology, in order to prepare high-performance silicon carbide chips. CVD involves introducing a gaseous precursor containing silicon and carbon elements into a high-temperature, vacuum reaction chamber, where a chemical reaction occurs on the heated substrate surface, generating solid silicon carbide which is then deposited on the substrate to form a dense coating.

[0003] However, in existing chemical vapor deposition (CVD) equipment, both the carrier plate and the silicon carbide substrate are placed horizontally, with the substrate plane facing the airflow. The airflow "stagnates" at the leading edge of the substrate and then bypasses the edge. This creates a low-pressure vortex region (i.e., a "tail") directly behind the substrate, resulting in low reactant concentration and byproduct accumulation in this area, leading to slow deposition rates and poor quality. Summary of the Invention

[0004] This application proposes a chemical vapor deposition apparatus for high-purity silicon carbide coatings for semiconductors, which has the advantages of fast deposition rate and good quality. It solves the problem that existing chemical vapor deposition equipment is prone to low reactant concentration and by-product accumulation in some areas when the substrate is placed horizontally and facing the gas flow.

[0005] To achieve the above objectives, this application adopts the following technical solution: a chemical vapor deposition apparatus for high-purity silicon carbide coating for semiconductors, comprising an inlet pipe and an exhaust pipe communicating with the inner cavity of a reaction chamber, wherein the reaction gas enters through the inlet pipe and exits through the exhaust pipe, a heating element disposed within the reaction chamber, the heating element heating the inner cavity of the reaction chamber to a predetermined deposition temperature, and a carrier plate movably disposed within the reaction chamber, the carrier plate being driven to rotate by a motor disposed within the reaction chamber, wherein a plurality of circumferentially arrayed wafer carriers are fixedly mounted on the outer edge of the carrier plate, the wafer carriers comprising positioning sleeves fixedly mounted on the carrier plate, the positioning sleeves being inclined relative to the carrier plate, a rotating shaft being rotatably connected inside the wafer carriers, and the rotating shaft rotating relative to the carrier plate when the carrier plate rotates, a base being disposed at the top of the rotating shaft, and a placement groove for placing silicon carbide substrates being opened at the top of the base.

[0006] Furthermore, a mounting base is fixedly installed at the top of the rotating shaft, and the base is movably fitted onto the top of the mounting base. The base is fixed to the mounting base by bolts. Through the detachable design of the base relative to the mounting base, a base with a corresponding size placement groove is set for silicon carbide substrates of different sizes, so that when changing silicon carbide of different sizes for coating, the corresponding base can be replaced.

[0007] Furthermore, a support plate is fixedly installed in the middle of the inner cavity of the reaction chamber. A gear ring is fixedly installed on the inner edge of the top of the support plate, and a helical gear is fixedly installed at the bottom of the gear ring. The helical gear meshes with the inner gear ring of the gear ring. When the motor drives the output shaft to rotate the carrier plate, the meshing action of the helical gear and the fixed gear ring causes the helical gear to rotate relative to the carrier plate. This causes the helical gear to drive the rotating shaft, mounting base, base, and silicon carbide substrate to rotate together relative to the helical gear, ensuring that every part of the silicon carbide substrate surface can uniformly experience different positions of the airflow. This averages out the deposition rate and properties of the entire substrate surface, thereby improving the uniformity of silicon carbide substrate deposition.

[0008] Furthermore, the base has a groove at its bottom that communicates with the interior of the rotating shaft. The base also has several through holes connecting the grooves and placement slots. A sliding plug is movably fitted inside the rotating shaft. A wire is fixedly connected to the side of the sliding plug away from the mounting base. The end of the wire away from the sliding plug extends outward from the helical gear and is fixedly connected to a gravity block. A spring is movably fitted outside the wire between the sliding plug and the helical gear. The spring force causes the sliding plug to tend to move closer to the mounting base, placing the silicon carbide substrate in the placement slot at the top of the base. During chemical vapor deposition, when the entire substrate carrier rotates with the carrier plate, the centrifugal force of the rotating gravity block pulls the wire puller and the slide plug away from the mounting base, overcoming the spring force. This creates a negative pressure suction inside the groove, which firmly adsorbs the silicon carbide substrate placed in the groove onto the base. This tilts the silicon carbide substrate and prevents it from falling off while it rotates with the carrier plate, the base, the mounting base, the rotating shaft, and the helical gear relative to the carrier plate. This eliminates the need for clamping mechanisms that would affect the deposition on the silicon carbide substrate surface.

[0009] Furthermore, a downwardly protruding annular isolation frame is fixedly installed on the inner edge of the bottom of the support plate, and an upwardly protruding annular support frame is fixedly installed on the middle of the top of the annular isolation frame. The carrier plate is rotatably connected to the top of the annular support frame through a plane bearing. The plane bearing is a high-temperature resistant bearing, which provides stable support for the carrier plate, enabling the carrier plate to rotate stably.

[0010] Furthermore, a linkage shaft is fixedly connected to the middle of the bottom end of the carrier plate. The middle of the linkage shaft is rotatably connected to the annular support frame via a bearing. A passive magnetic disk located inside the annular isolation frame is fixedly installed at the bottom end of the linkage shaft, and the passive magnetic disk is close to the bottom of the inner cavity of the annular isolation frame. A downwardly protruding positioning support frame is fixedly installed at the middle of the bottom end of the annular isolation frame. The motor is fixedly installed at the bottom of the positioning support frame. The output shaft of the motor extends into the interior of the positioning support frame and is fixedly installed with an active magnetic disk. The top of the active magnetic disk is close to but does not contact the bottom of the annular isolation frame. Magnetic blocks that attract each other are respectively provided on the opposite sides of the active and passive magnetic disks. When the motor drives the output shaft to rotate the active magnetic disk, the magnetic coupling between the active and passive magnetic disks can be used to drive the passive magnetic disk to rotate, thereby driving the linkage shaft and the carrier plate to rotate. This improves the sealing effect inside the reaction chamber and prevents leakage caused by easy wear of the sealing structure at the rotating part when the carrier plate is directly driven to rotate by the motor's output shaft.

[0011] Furthermore, an annular cover located outside the carrier plate is fixedly installed on the top of the support plate. A gap is reserved between the inner side of the annular cover and the outer side of the carrier plate for the flow of reactive gas, so that the reactive gas can flow out through the gap and thus flow evenly to the outside along the surface of the carrier plate. An annular cylinder is provided on the outer side of the annular cover, and heating elements distributed vertically are provided on the inner side of the annular cylinder. The heating elements heat the inner cavity of the annular cover so that the inner side of the annular cover reaches the preset deposition temperature.

[0012] Furthermore, the angle between the inclined surface of the base and the plane of the carrier plate does not exceed 30 degrees. By setting the base at an angle with the airflow direction, the airflow can be guided to sweep more smoothly across the surface of the silicon carbide substrate, greatly reducing the tail shadow area and making the airflow field more uniform, thereby improving the quality of the coating on the surface of the silicon carbide substrate. In addition, the inclined angle causes the airflow to generate a tangential velocity on the substrate surface, which helps to "sweep away" the consumed reactive gases and replenish new reactants in time. Byproducts produced by the chemical reaction (such as HCl) can also be carried away from the substrate surface more quickly by this tangential airflow, preventing them from being re-adsorbed or causing corrosion to the growth surface, thereby obtaining a higher quality epitaxial layer, which further improves the effect of the coating on the surface of the silicon carbide substrate, while preventing the problem of excessively large inclined angles affecting the quality of chemical vapor deposition.

[0013] The beneficial effects of this invention are as follows: 1. The chemical vapor deposition apparatus for high-purity silicon carbide coating of semiconductors provided in this application, by setting an inclined base on the carrier plate, so that the silicon carbide substrate on the base is at a certain angle to the airflow direction, can guide the airflow to sweep more smoothly across the surface of the silicon carbide substrate, greatly reduce the tail shadow area, make the airflow field more uniform, thereby improving the quality of the coating on the surface of the silicon carbide substrate. In addition, the inclined angle causes the airflow to generate a tangential velocity on the substrate surface, which helps to "sweep away" the consumed reaction gas and replenish the new reactants in time. The by-products produced by the chemical reaction can also be carried away from the substrate surface more quickly by this tangential airflow, preventing them from being re-adsorbed or causing corrosion to the growth surface, thereby obtaining a higher quality epitaxial layer, and further improving the effect of the coating on the surface of the silicon carbide substrate.

[0014] 2. The chemical vapor deposition apparatus for high-purity silicon carbide coating of semiconductor provided in this application has a structural design that ensures that every part of the silicon carbide substrate surface can uniformly experience different positions of the airflow while rotating with the carrier plate, thereby averaging the deposition rate and properties of the entire substrate surface and improving the uniformity of silicon carbide substrate deposition. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort: Figure 1 This is a cross-sectional structural diagram of the reaction chamber of the present invention; Figure 2 for Figure 1 The front view; Figure 3 for Figure 1 Schematic diagram of the intermediate wafer carrier device; Figure 4 This is a cross-sectional structural diagram of the slide carrier device in Embodiment 2 of the present invention.

[0016] In the diagram: 1. Reaction chamber; 2. Support plate; 3. Annular isolation frame; 4. Annular support frame; 5. Carrier plate; 6. Linkage shaft; 7. Passive magnetic disk; 8. Positioning support frame; 9. Motor; 10. Active magnetic disk; 11. Carrier device; 111. Positioning sleeve; 112. Rotating shaft; 113. Mounting base; 114. Base; 1141. Groove; 1142. Through hole; 115. Helical gear; 116. Sliding plug; 117. Wire drawing; 118. Gravity block; 119. Spring; 12. Gear ring; 13. Air inlet pipe; 14. Annular cover; 15. Annular cylinder; 16. Heating element; 17. Exhaust pipe. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Example 1, as Figures 1-2 A chemical vapor deposition apparatus for high-purity silicon carbide coating in semiconductors includes a reaction chamber 1. A support plate 2 is fixedly disposed in the middle of the inner cavity of the reaction chamber 1. A downwardly protruding annular isolation frame 3 is fixedly installed on the inner edge of the bottom of the support plate 2. An upwardly protruding annular support frame 4 is fixedly installed in the middle of the top of the annular isolation frame 3. A carrier plate 5 is mounted on the top of the annular support frame 4 via a planar bearing (the planar bearing is a high-temperature resistant bearing, such as a ceramic bearing made of silicon nitride, zirconium oxide, etc., and all bearings subsequently installed in the reaction chamber 1 are high-temperature resistant bearings). A linkage shaft 6 is fixedly connected to the middle of the bottom end of the carrier plate 5. The middle of the linkage shaft 6 is rotatably connected to the annular support frame 4 via a bearing. A support frame located on the annular isolation frame is fixedly installed at the bottom end of the linkage shaft 6. The passive magnetic disk 7 inside the ring-shaped isolation frame 3 is located near the bottom of the inner cavity of the ring-shaped isolation frame 3. A downwardly protruding positioning support frame 8 is fixedly installed in the middle of the bottom end of the ring-shaped isolation frame 3. A motor 9 is fixedly installed at the bottom of the positioning support frame 8. The output shaft of the motor 9 extends into the interior of the positioning support frame 8 and is fixedly installed with an active magnetic disk 10. The top of the active magnetic disk 10 is close to the bottom of the ring-shaped isolation frame 3 but does not contact it. Magnetic blocks that attract each other are respectively provided on the opposite side of the active magnetic disk 10 and the passive magnetic disk 7. When the motor 9 drives the output shaft to rotate the active magnetic disk 10, the magnetic coupling between the active magnetic disk 10 and the passive magnetic disk 7 can be used to drive the passive magnetic disk 7 to rotate, thereby driving the linkage shaft 6 and the carrier plate 5 to rotate.

[0019] Several circumferentially arrayed slide carriers 11 are fixedly disposed on the outer edge of the top of the carrier plate 5. Please refer to [reference needed]. Figures 1-3The slide carrier device 11 includes a positioning sleeve 111 fixedly mounted on a carrier plate 5. The positioning sleeve 111 is inclined relative to the carrier plate 5. A rotating shaft 112 is rotatably connected inside the positioning sleeve 111 via a bearing. A mounting base 113 is fixedly mounted on the top of the rotating shaft 112. A base 114 is fitted onto the top of the mounting base 113. The angle between the inclined surface of the base 114 and the plane of the carrier plate 5 does not exceed 30 degrees. The base 114 is fixed to the mounting base 113 by bolts. A placement groove is provided on the top of the base 114. Through the detachable design of the base 114, a placement groove is provided. The base 114 is provided with placement slots of different sizes so that the corresponding base 114 can be installed according to the size of the semiconductor silicon carbide substrate. A helical gear 115 is fixedly installed at the bottom end of the rotating shaft 112, and a gear ring 12 is fixedly installed on the inner edge of the top of the support plate 2. The helical gear 115 meshes with the inner gear ring of the gear ring 12. When the motor 9 drives the carrier plate 5 to rotate, the carrier device 11 rotates with the carrier plate 5. By utilizing the meshing action of the helical gear 115 and the gear ring 12, the helical gear 115 drives the rotating shaft 112, the mounting base 113 and the base 114 to rotate relative to the carrier plate 5.

[0020] An air inlet pipe 13 is provided at the middle of the top of the reaction chamber 1. One end of the air inlet pipe 13 extends into the interior of the reaction chamber 1, and the bottom end of the air inlet pipe 13 is located above the base 114. The other end of the air inlet pipe 13 is connected to the gas supply equipment so that the reaction gas can be introduced through the air inlet pipe 13 when performing chemical vapor deposition on the semiconductor silicon carbide substrate. An annular cover 14 located outside the carrier plate 5 is fixedly installed on the top of the support plate 2. A gap for the reaction gas to flow is reserved between the inner side of the annular cover 14 and the outer side of the carrier plate 5. An annular cylinder 15 is provided on the outer side of the annular cover 14. Heating elements 16 distributed vertically are provided on the inner side of the annular cylinder 15. The inner cavity of the annular cover 14 is heated by the heating elements 16. The front of the reaction chamber 1 is provided with a slot and a sealing door structure (not shown in the figure) located between the two heating elements 16 so that the silicon carbide substrate can be placed on the base 114 or removed from the base 114.

[0021] The bottom of the annular isolation frame 3 is connected to two exhaust pipes 17 on both sides. The two exhaust pipes 17 are connected to the gas outlet pipe through a three-way pipe. One end of the gas outlet pipe is connected to a negative pressure pump. The negative pressure pump is used to evacuate the inside of the reaction chamber 1 and to discharge the reaction gas during the vapor deposition of the silicon carbide substrate coating.

[0022] In use, the silicon carbide substrate to be coated is first placed in the placement slot at the top of the base 114. Then, the inside of the reaction chamber 1 is evacuated, and the inner chamber of the annular cover 14 is heated by the heating element 16 to heat the silicon carbide substrate placed on the annular cover 14 to the predetermined deposition temperature. Then, the reaction gas is introduced through the gas inlet pipe 13, and the flow rate of each gas is precisely controlled. At the same time, the motor 9 is started to drive the output shaft to rotate the active magnetic disk 10. The magnetic coupling between the active magnetic disk 10 and the passive magnetic disk 7 drives the linkage shaft 6, the carrier plate 5 and the substrate carrier device 11 to rotate together. At the same time, the inclined plate in the substrate carrier device 11 rotates. The meshing action of gear 115 and gear ring 12 causes helical gear 115 to drive rotating shaft 112, mounting base 113, base 114 and silicon carbide substrate to rotate relative to carrier plate 5. Utilizing the inclined setting of base 114, the silicon carbide substrate placed on it rotates, allowing the reaction gas to act evenly on the surface of silicon carbide substrate and react chemically with the surface of silicon carbide substrate. Ultimately, solid silicon carbide is produced and bonded to the structure of substrate crystals, realizing chemical vapor deposition. The gas after reaction flows through the gap between the outer side of carrier plate 5 and the inner side of annular cover 14 into the interior of annular isolation frame 3, and then flows out from two exhaust pipes 17.

[0023] Example 2, as Figure 4 Based on Embodiment 1, the bottom of the base 114 has a groove 1141 communicating with the interior of the rotating shaft 112. The base 114 has several through holes 1142 communicating with the grooves 1141 and the placement slots. A sliding plug 116 is movably fitted inside the rotating shaft 112. A wire 117 is fixedly connected to the side of the sliding plug 116 away from the mounting base 113. The end of the wire 117 away from the sliding plug 116 extends outward from the helical gear 115 and is fixedly connected to a gravity block 118. A spring 119 is movably fitted outside the wire 117 between the sliding plug 116 and the helical gear 115. The elastic force of the spring 119 causes the sliding plug 116 to tend to move towards the end closer to the mounting base 113. When the silicon carbide substrate in the top placement groove is subjected to chemical vapor deposition, the entire substrate carrier device 11 rotates together with the carrier plate 5. The centrifugal force of the rotating gravity block 118 pulls the wire 117 and the slide plug 116 to overcome the elastic force of the spring 119 and move away from the mounting base 113. This generates a negative pressure suction inside the groove 1141, thereby firmly adsorbing the silicon carbide substrate in the placement groove onto the base 114. This allows the silicon carbide substrate to be tilted and, while rotating with the carrier plate 5, also rotates with the base 114, mounting base 113, rotating shaft 112, and helical gear 115 relative to the carrier plate 5, preventing the substrate from falling off. This eliminates the need for a clamping mechanism that would affect the deposition on the surface of the silicon carbide substrate.

[0024] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A chemical vapor deposition apparatus for high-purity silicon carbide coating for semiconductors, comprising an inlet pipe and an outlet pipe communicating with the inner cavity of a reaction chamber, wherein reaction gas enters through the inlet pipe and exits through the outlet pipe, and a heating element disposed within the reaction chamber heats the inner cavity of the reaction chamber to a predetermined deposition temperature, characterized in that, It also includes a carrier plate that is movably installed inside the reaction chamber, and the carrier plate is driven to rotate by a motor installed inside the reaction chamber. Several circumferentially arrayed wafer carriers are fixedly installed on the outer edge of the carrier plate. Each wafer carrier includes a positioning sleeve fixedly installed on the carrier plate. The positioning sleeve is inclined relative to the carrier plate. A rotating shaft is rotatably connected inside the wafer carrier, and the rotating shaft also rotates relative to the carrier plate when the carrier plate rotates. A base is provided at the top of the rotating shaft, and a placement groove for placing silicon carbide substrates is opened on the top of the base.

2. The chemical vapor deposition apparatus for high-purity silicon carbide coating for semiconductors according to claim 1, characterized in that, A mounting base is fixedly installed at the top of the rotating shaft, and the base is movably fitted onto the top of the mounting base, and the base is fixed to the mounting base by bolts.

3. The chemical vapor deposition apparatus for high-purity silicon carbide coating for semiconductors according to claim 2, characterized in that, A support plate is fixedly installed in the middle of the inner cavity of the reaction chamber. A gear ring is fixedly installed on the inner edge of the top of the support plate. A helical gear is fixedly installed at the bottom of the gear ring. The helical gear meshes with the inner gear ring of the gear ring.

4. The chemical vapor deposition apparatus for high-purity silicon carbide coating for semiconductors according to claim 3, characterized in that, The base has a groove at its bottom that communicates with the interior of the rotating shaft. The base has several through holes that connect the grooves and the placement slots. A sliding plug is movably fitted inside the rotating shaft. A wire is fixedly connected to the side of the sliding plug away from the mounting base. The end of the wire away from the sliding plug extends out of the helical gear and is fixedly connected to a gravity block. A spring is movably fitted on the outside of the wire between the sliding plug and the helical gear.

5. The chemical vapor deposition apparatus for high-purity silicon carbide coating for semiconductors according to claim 3, characterized in that, A downwardly protruding annular isolation frame is fixedly installed on the inner edge of the bottom of the support plate, and an upwardly protruding annular support frame is fixedly installed on the middle of the top of the annular isolation frame. The carrier plate and the top of the annular support frame are rotatably connected by a planar bearing.

6. The chemical vapor deposition apparatus for high-purity silicon carbide coating for semiconductors according to claim 5, characterized in that, A linkage shaft is fixedly connected to the middle of the bottom end of the carrier plate. The middle of the linkage shaft is rotatably connected to the annular support frame via a bearing. A passive magnetic disk located inside the annular isolation frame is fixedly installed at the bottom end of the linkage shaft, and the passive magnetic disk is close to the bottom of the inner cavity of the annular isolation frame. A downwardly protruding positioning support frame is fixedly installed at the middle of the bottom end of the annular isolation frame. The motor is fixedly installed at the bottom of the positioning support frame. The output shaft of the motor extends into the interior of the positioning support frame and is fixedly installed with an active magnetic disk. The top of the active magnetic disk is close to but does not contact the bottom of the annular isolation frame. Magnetic blocks that attract each other are respectively provided on the opposite sides of the active magnetic disk and the passive magnetic disk.

7. The chemical vapor deposition apparatus for high-purity silicon carbide coating for semiconductors according to claim 3, characterized in that, The top of the support plate is fixedly installed with an annular cover located outside the carrier plate. An annular cylinder is provided outside the annular cover, and heating elements are arranged vertically on the inner side of the annular cylinder.

8. The chemical vapor deposition apparatus for high-purity silicon carbide coating for semiconductors according to claim 1, characterized in that, The angle between the inclined surface of the base and the plane of the carrier plate does not exceed thirty degrees.

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