Device and method for inhibiting white spots on back of wafer in epitaxial process

Abstract

The embodiment of the invention provides a device and method for inhibiting white spots on the back of a wafer in the epitaxy process, the device for inhibiting the white spots on the back of the wafer in the epitaxy process is optimized, the device comprises a graphite disc, a cyclone tray, a supporting piece and a gas supply device, the top of the graphite disc is used for placing a substrate, the graphite disc is provided with a through type air hole, and the cyclone tray is arranged in the through type air hole; the cyclone tray is arranged at the bottom of the graphite plate; the supporting piece is used for supporting the graphite disc, so that an airflow space is formed between the graphite disc and the cyclone tray, and the airflow space is communicated with the air hole; the cyclone tray can drive the graphite disc to rotate through the supporting piece; the gas supply device is used for generating gas flow into the gas flow space, so that the pressure intensity of the lower surface of the substrate is smaller than that of the upper surface, the Bernoulli effect is generated, the substrate is fully attached to the graphite disc, and therefore the probability that epitaxial growth gas makes contact with the lower surface of the substrate is reduced; the problem of back white mist abnormity caused by the fact that epitaxial gas enters the carbon surface of the substrate to participate in the reaction is solved, and the yield of the epitaxial wafer is further improved.

Description

Technical Field

[0001] The present application relates to the technical field of silicon carbide epitaxial growth, and in particular to a device and method for suppressing white spots on the back of a wafer during an epitaxial growth process. Background Art

[0002] Silicon carbide (SiC) is a third-generation semiconductor material that has been applied in the fields of smart grids, electric vehicles, rail transportation, switching power supplies, industrial motors, and household appliances, and has shown good development prospects. Unlike the traditional silicon power device manufacturing process, silicon carbide power devices cannot be directly manufactured on silicon carbide single crystal materials. It is necessary to grow high-quality epitaxial materials on the conductive single crystal substrate and manufacture various devices on the epitaxial layer.

[0003] At present, during the epitaxial growth process of silicon carbide, it is easy for the carbon surface of the substrate to produce white fog-like abnormalities, generate other crystal forms, and the flatness of the epitaxial wafer to deteriorate, which in turn leads to a decrease in the yield of the epitaxial wafer. Summary of the invention

[0004] The purpose of the embodiment of the present application is to provide a device and method for suppressing white spots on the back of the wafer during epitaxy, so as to solve the problem of white fog abnormality on the carbon surface of the substrate, the generation of other crystal forms, and the deterioration of the flatness of the epitaxial wafer. The specific technical solution is as follows:

[0005] An embodiment of the first aspect of the present application provides a device for suppressing white spots on the back of a wafer during an epitaxial process. The device for suppressing white spots on the back of a wafer during an epitaxial process comprises: a graphite disk, a cyclone tray, a support member and a gas supply device. The top of the graphite disk is used to place a substrate. The graphite disk is provided with a through-type air hole. The air hole is arranged along a first direction, and the first direction is the height direction of the device for suppressing white spots on the back of a wafer during an epitaxial process. The cyclone tray is arranged at the bottom of the graphite disk, and the cyclone tray can rotate. The support member is arranged between the graphite disk and the cyclone tray, and is used to support the graphite disk so that an airflow space is formed between the graphite disk and the cyclone tray, and the airflow space is connected to the air hole; and the cyclone tray can drive the graphite disk to rotate through the support member. The gas supply device is used to generate an airflow into the airflow space so that the pressure on the lower surface of the substrate is less than the pressure on the upper surface of the substrate.

[0006] In some embodiments, the support member includes a plurality of support columns, and the plurality of support columns are fixedly connected to a side of the graphite disk close to the cyclone tray. A plurality of slots are provided on a side of the cyclone tray close to the graphite disk, and positions of the slots correspond to positions of the support columns. An end of the support column away from the graphite disk is placed in the slot of the cyclone tray.

[0007] In some embodiments, the support member includes a plurality of support columns, and the plurality of support columns are fixedly connected to a side of the cyclone tray close to the graphite disk. A slot is provided on a side of the graphite disk close to the cyclone tray, and the position of the slot corresponds to the position of the support column. An end of the support column away from the cyclone tray is placed in the slot of the graphite disk.

[0008] In some embodiments, the cross-sectional shape of the support column is adapted to the cross-sectional shape of the slot.

[0009] In some embodiments, the plurality of support columns are evenly distributed along the circumferential direction.

[0010] In some embodiments, there are multiple pores, and the multiple pores are radially distributed on the graphite disk.

[0011] In some embodiments, the gas supply device includes a gas pipeline, and a gas outlet end of the gas pipeline is aligned with the air flow space.

[0012] In some embodiments, a flow regulating valve and a shut-off valve are provided on the gas pipeline, wherein the flow regulating valve is used to regulate the gas flow in the gas pipeline, and the shut-off valve is used to control the on-off of the gas in the gas pipeline.

[0013] In some embodiments, the device for suppressing white spots on the back of the wafer during the epitaxial growth process also includes a graphite ring, which is arranged on the upper part of the graphite disk, and the graphite ring has a receiving hole arranged along the first direction, and the substrate is arranged in the receiving hole, and the graphite ring is used to limit the circumferential movement of the substrate; the receiving hole of the graphite ring includes a first hole segment and a second hole segment, and the aperture of the first hole segment is smaller than the aperture of the second hole segment; the graphite ring can overlap the upper surface of the graphite disk, and the top part of the graphite disk is located in the second hole segment, and the substrate is placed in the first hole segment.

[0014] An embodiment of the second aspect of the present application provides a method for suppressing white spots on the back of a wafer during epitaxial growth, comprising:

[0015] A high-speed airflow is introduced into the airflow space formed between the graphite disk with through-type air holes and the cyclone tray through a gas supply device, so that the pressure on the lower surface of the substrate is lower than the pressure on the upper surface of the substrate, thereby allowing the substrate to be adsorbed on the graphite disk.

[0016] Beneficial effects of the embodiments of the present application:

[0017] The device for suppressing white spots on the back of the wafer during the epitaxial growth process provided in the embodiment of the present application is provided with a support member so that a gap is left between the cyclone tray and the graphite disk to form an airflow space for gas to pass through, and the graphite disk is provided with a through-type air hole, and the airflow space is connected to the through-type air hole. The gas supply device is used to provide a high-speed airflow into the airflow space between the graphite disk and the cyclone tray, which can make the pressure on the lower surface of the substrate on the graphite disk less than the pressure on the upper surface of the substrate, produce a Bernoulli effect, and enable the substrate to be more firmly adsorbed on the graphite disk, so that the substrate and the graphite disk are fully fitted, thereby reducing the probability of the epitaxial growth gas contacting the carbon surface of the substrate, solving the problem of epitaxial-related gases entering the carbon surface of the substrate to react and produce white mist anomalies, and generating other crystal forms, optimizing the flatness of the epitaxial wafer, and thus improving the yield of the epitaxial wafer.

[0018] Of course, implementing any product or method of the present application does not necessarily require achieving all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application, and for ordinary technicians in this field, other embodiments can also be obtained based on these drawings.

[0020] Figure 1 An exploded perspective view of a device and a substrate for suppressing white spots on the back of a wafer during epitaxy provided in an embodiment of the present application;

[0021] Figure 2 for Figure 1 An exploded view of a device for suppressing white spots on the back side of a wafer during an epitaxial process;

[0022] Figure 3 for Figure 1 An isometric view of a device for suppressing white spots on the back of a wafer during an epitaxial process;

[0023] Figure 4 for Figure 1 An axial side view of a device and a substrate for suppressing white spots on the back of a wafer during an epitaxial process;

[0024] Figure 5 A perspective view of a device for suppressing white spots on the back of a wafer during epitaxy provided by an embodiment of the present application and a substrate after installation;

[0025] Figure 6 A detailed perspective view of the connection between a graphite ring and a graphite disk in a device for suppressing white spots on the back of a wafer during epitaxy provided in an embodiment of the present application;

[0026] Figure 7A schematic diagram of a device for suppressing white spots on the back of a wafer during epitaxy and simulation results in a growth chamber provided in an embodiment of the present application;

[0027] Figure 8 for Figure 7 The schematic diagram of the simulation results shown is an enlarged schematic diagram of the device for suppressing white spots on the back side of the wafer during the epitaxial growth process.

[0028] Reference numerals:

[0029] Graphite plate 10; air hole 11; cyclone tray 20; air flow space 201; support member 30; support column 31; slot 32; gas supply device 40; gas pipeline 41; graphite ring 50; receiving hole 51; first hole section 511; second hole section 512; substrate 60; warm color system 71; transitional color system 72; cold color system 73;

[0030] The first direction X. DETAILED DESCRIPTION

[0031] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field based on the present application belong to the scope of protection of the present application.

[0032] During the current epitaxial growth of silicon carbide, the substrate is placed in a graphite disk of corresponding size, and epitaxial growth is carried out in a related environment. The fit between the substrate and the graphite disk is completely pressed by the weight of the substrate itself, and due to the difference in doping concentration between the substrate and the epitaxial wafer, as the epitaxial thickness increases, the surface shape will gradually become larger, and the fit gap between the wafer and the graphite disk will become larger, causing epitaxial-related gases to enter the carbon surface of the substrate, and the carbon surface of the substrate will produce white spots, white mist, and generate other crystal forms and other abnormalities. And as the surface shape becomes larger, the fit between the wafer and the graphite disk becomes worse, and the radial temperature field distribution becomes more uneven, resulting in further deterioration of the flatness of the epitaxial wafer. It should be noted that the substrate is the raw material for growth, and the substrate growth (after epitaxy) is called an epitaxial wafer, which can also be called a wafer. The back of the wafer is the carbon surface of the wafer, that is, Figure 1 The lower surface of the substrate 60.

[0033] The embodiment of the first aspect of the present application provides a device for suppressing white spots on the back of a wafer during epitaxy, such as Figure 1 and Figure 2As shown, the device for suppressing white spots on the back of the wafer during the epitaxial process includes: a graphite disk 10, a cyclone tray 20, a support 30 and a gas supply device 40, the top of the graphite disk 10 is used to place the substrate 60, the graphite disk 10 is provided with a through-type pore 11, the pore 11 is arranged along the first direction X, and the first direction X is the height direction of the device for suppressing white spots on the back of the wafer during the epitaxial process; the cyclone tray 20 is arranged at the bottom of the graphite disk 10, and the cyclone tray 20 can drive the graphite disk 10 to rotate; the support 30 is arranged between the graphite disk 10 and the cyclone tray 20, and is used to support the graphite disk 10, so that an airflow space 201 is formed between the graphite disk 10 and the cyclone tray 20, and the airflow space 201 is connected to the pore 11; and the cyclone tray 20 can drive the graphite disk 10 to rotate through the support 30; the gas supply device 40 is used to generate an airflow into the airflow space, so that the pressure on the lower surface of the substrate 60 is less than the pressure on the upper surface of the substrate 60.

[0034] The device for suppressing white spots on the back of the wafer during the epitaxial growth process provided in the embodiment of the present application is configured such that a gap is left between the cyclone tray 20 and the graphite disk 10 by setting a support member 30, thereby forming an air flow space 201 for gas to pass through, and the graphite disk 10 is provided with a through-type air hole 11, and the air flow space 201 is connected to the through-type air hole 11, that is, the substrate 60 is placed on the graphite disk 10, and since the graphite disk 10 is provided with the through-type air hole 11, the substrate 60 can be exposed through the through-type air hole 11. The gas supply device 40 is used to provide a high-speed airflow into the airflow space 201 between the graphite disk 10 and the cyclone tray 20. The force of the high-speed airflow can act on the substrate 60 through the through-type air holes 11. That is to say, under the action of the high-speed airflow, the pressure on the lower surface of the substrate 60 on the graphite disk 10 can be made smaller than the pressure on the upper surface of the substrate 60, thereby generating a Bernoulli effect, so that the substrate 60 can be more firmly adsorbed on the graphite disk 10, and the substrate 60 and the graphite disk 10 can be fully fitted, thereby reducing the probability of the epitaxial growth gas contacting the carbon surface of the substrate, solving the problem of the epitaxial-related gas entering the carbon surface of the substrate to react and produce white mist anomalies and generate other crystal forms, and can also optimize the flatness of the epitaxial wafer, thereby improving the yield of the epitaxial wafer.

[0035] like Figure 5 , Figure 7 and Figure 8 As shown, Figure 7 The embodiment of the present application provides a device for suppressing white spots on the back of the wafer during epitaxy and a schematic diagram of the simulation results in the growth chamber, that is, a device for suppressing white spots on the back of the wafer during epitaxy and a schematic diagram of the pressure distribution in the growth chamber; wherein, Figure 7 On the left is the corresponding color scheme for the standard pressure distribution; Figure 8 for Figure 7 The schematic diagram of the simulation result is shown in the enlarged schematic diagram of the device for suppressing white spots on the back of the wafer during the epitaxy process. Figure 3and Figure 5 Taking the air intake on the left side as an example, according to the simulation results, due to the air intake on the left side, the pressure on the left side of the device for suppressing white spots on the back of the wafer during epitaxy is greater than the pressure on the right side of the device for suppressing white spots on the back of the wafer during epitaxy; since the high-speed airflow acts on the airflow space 201, the pressure value of the upper surface of the substrate 60 on the graphite disk 10 is greater than the pressure value of the lower surface of the substrate 60, that is, in the simulation results, the pressure value of the upper surface of the substrate 60 is a warm color system 71, the middle position of the substrate 60 is a transitional color system 72, and the pressure value of the lower surface of the substrate 60 is a cold color system 73. Therefore, it can be seen from the simulation results that the Bernoulli effect can be generated, so that the substrate 60 can be more firmly adsorbed on the graphite disk 10, so that the substrate 60 and the graphite disk 10 are fully fitted, thereby reducing the probability of the epitaxial growth gas contacting the carbon surface of the substrate.

[0036] It should be noted that the warm color system 71 represents positive pressure, and the darker the color in the warm color system 71, the greater the pressure. For example, the pressure value at the red is greater than the pressure value at the yellow. The transition color system 72 represents a slight positive pressure, and the pressure is less than the pressure at the warm color system 71. The cold color system 73 represents negative pressure. The darker the cold color, the greater the negative pressure value. For example, the negative pressure at the dark blue is greater than the negative pressure at the light blue, that is, there is a negative pressure between the graphite disk 10 and the substrate 60, and the upper surface of the substrate 60 is a relatively large positive pressure, so that the substrate 60 can only be adsorbed on the graphite disk 10. In actual application, the direction in which the gas supply device 40 provides high-speed airflow to the airflow space 201 between the graphite disk 10 and the cyclone tray 20 can also be other directions such as the right side, and the present application does not limit the air intake direction.

[0037] The embodiments of the present application achieve unexpected technical effects using a simple structure, namely, solving the problem in the prior art that epitaxial-related gases react with the carbon surface of the substrate to produce white mist anomalies and generate other crystal forms. It can also optimize the flatness of the epitaxial wafer, thereby improving the yield of the epitaxial wafer, and has outstanding substantial characteristics and significant progress.

[0038] When the substrate 60 is placed horizontally on the graphite disk 10 , the air flow channel formed by the pores 11 is perpendicular to the substrate 60 , one end of the pores 11 is in contact with the lower surface of the substrate 60 , and the other end is exposed in the air flow space 201 .

[0039] It should be noted that the device for suppressing white spots on the back of the wafer during the epitaxial growth process is applied to the silicon carbide epitaxial growth environment. During the silicon carbide epitaxial growth process, the upper surface of the substrate 60, that is, the silicon surface of the substrate 60, is the growth surface of the epitaxial wafer, and the lower surface of the substrate 60 is the carbon surface. The carbon surface is in contact with the graphite disk 10 and does not participate in the epitaxial growth process.

[0040] It should be noted that the cyclone tray is a tray that is driven to rotate by pneumatic means, and the rotation of the cyclone tray 20 drives the graphite tray 10 to rotate. In addition, the cyclone tray 20 can also be replaced by other rotatable trays.

[0041] In actual application, epitaxial growth of silicon carbide is often carried out in a growth chamber (not shown), the graphite disk 10, the cyclone tray 20, and the support 30 are placed inside the growth chamber, and the gas supply device 40 can be arranged on the side wall of the growth chamber. When the gas supply device 40 is a gas pipeline 41, a through hole can be provided on the side wall of the growth chamber, and the gas pipeline 41 extends into the growth chamber through the through hole, and the gas outlet is aligned with the gap between the graphite disk 10 and the cyclone tray 20. The device for suppressing white spots on the back of the wafer during epitaxy often also includes a growth gas supply device (not shown), which is used to provide growth gas to the upper surface of the substrate 60. According to the Bernoulli effect, the greater the flow rate of the fluid, the smaller the pressure. The flow rate of the high-speed airflow provided by the gas supply device 40 to the airflow space 201 is greater than the growth gas flow rate above the substrate 60, so the pressure on the lower surface of the substrate 60 is less than the pressure on the upper surface of the substrate 60. Figure 1 The arrow pointing from the right side of the gas supply device 40 is the direction of the high-speed gas flow. In the embodiment of the present application, there is no restriction on the flow rate of the high-speed gas flow. The flow rate of the high-speed gas flow provided by the gas supply device is greater than the flow rate of the growth gas above the substrate 60, so that the pressure on the lower surface of the substrate 60 can be less than the pressure on the upper surface of the substrate 60, thereby achieving that the substrate 60 is tightly adsorbed on the graphite disk.

[0042] In some embodiments of the present application, Figures 1 to 4 As shown, the support member 30 includes a plurality of support columns 31, and the plurality of support columns 31 are fixedly connected to the side of the graphite disk 10 close to the cyclone tray 20. The side of the cyclone tray 20 close to the graphite disk 10 is provided with a plurality of slots 32, and the positions of the slots 32 correspond to the positions of the support columns 31. The end of the support column 31 away from the graphite disk 10 is placed in the slot 32 of the cyclone tray 20.

[0043] In the embodiment of the present application, since the support column 31 is connected to the graphite disk 10, the graphite disk 10 is connected to the cyclone tray 20 through the support column 31, and the support column 31 supports the graphite disk 10, so that an airflow space for high-speed airflow to pass through is formed between the graphite disk 10 and the cyclone tray 20. Since the slot 32 is provided on the cyclone tray 20, the end of the support column 31 away from the graphite disk 10 can be placed in the slot 32, and the outer wall of the support column 31 is against the inner wall of the slot 32, so that the cyclone tray 20 drives the graphite disk 10 to rotate through the support member 30.

[0044] In some embodiments of the present application, the support member 30 includes a plurality of support columns 31, and the plurality of support columns 31 are fixedly connected to the side of the cyclone tray 20 close to the graphite disk 10. A slot 32 is provided on the side of the graphite disk 10 close to the cyclone tray 20. The position of the slot 32 corresponds to the position of the support column 31. The end of the support column 31 away from the cyclone tray 20 is placed in the slot 32 of the graphite disk 10.

[0045] In the embodiment of the present application, since the support column 31 is connected to the cyclone tray 20, the graphite disk 10 is connected to the cyclone tray 20 through the support column 31, and the support column 31 supports the graphite disk 10, so that an airflow space for high-speed airflow to pass through is formed between the graphite disk 10 and the cyclone tray 20. Since the slot 32 is provided on the graphite disk 10, the end of the support column 31 away from the cyclone tray 20 can be placed in the slot 32, and the outer wall of the support column 31 is against the inner wall of the slot 32, so that the cyclone tray 20 drives the graphite disk 10 to rotate through the support member 30.

[0046] The support column 31 can be a cylinder or a polygonal column, and the corresponding shape of the slot 32 can be a circle or a polygon. The number of the support columns 31 can also be two, four, five, etc. This application does not limit the number and shape of the support columns 31.

[0047] In some embodiments of the present application, Figures 1 to 4 As shown, the cross-sectional shape of the support column 31 is adapted to the cross-sectional shape of the slot 32. For example, the support column 31 is a cylinder, and the slot 32 is a circular slot 32. Since the support column 31 is circular, the slot 32 is also a corresponding circular slot 32. Therefore, in the process of placing the support column 31 in the slot 32, there is no requirement for the assembly direction, which can reduce the assembly time.

[0048] In some embodiments of the present application, a plurality of support columns 31 are evenly distributed along the circumferential direction. Since a plurality of support columns 31 are evenly distributed along the circumferential direction of the graphite disk 10, the graphite disk 10 and the cyclone tray 20 can be subjected to more uniform and stable forces, thereby improving the stability of the device during operation, and enabling the graphite disk 10 to be stably supported above the cyclone tray 20. For example, the number of support columns 31 may be three, and the projection lines of the three support columns 31 on the graphite disk 10 form an equilateral triangle.

[0049] In some embodiments of the present application, Figure 3 As shown, there are multiple pores 11 , and the multiple pores 11 are radially distributed on the graphite disk 10 .

[0050] In the embodiment of the present application, the number of the pores 11 is multiple, such as Figure 3As shown, multiple pores 11 are arranged in parallel and spaced apart to form pore rows, and multiple pore rows are arranged crosswise, so that multiple pores 11 are distributed radially outward from the center of the graphite disk 10. The pores 11 near the center of the graphite disk 10 are denser, so that the Bernoulli effect fully acts on the center of the substrate 60 on the graphite disk 10. Through the above arrangement, the uniformity of the distribution of the pores 11 can be improved, so that the Bernoulli effect can better act on the substrate 60, and the substrate 60 can be more closely attached to the graphite disk 10.

[0051] In some other embodiments, the plurality of pores 11 may also be distributed in a matrix array, and the present application does not limit the distribution of the pores 11 .

[0052] In some embodiments of the present application, the gas supply device 40 includes a gas pipeline 41 , and a gas outlet end of the gas pipeline 41 is aligned with the air flow space 201 .

[0053] In the present application embodiment, Figures 1 to 3 As shown, the gas pipeline 41 is a planar gas pipeline, and the width of the gas pipeline 41 can be equal to the distance between the two farthest gas holes 11 on the graphite disk 10. The gas outlet end of the planar gas pipeline is aligned with the gas flow space 201, and a high-speed gas flow is provided in the gas flow space 201. The pressure on the lower surface of the substrate 60 is lower than the pressure on the upper surface through the Bernoulli effect, so that the substrate 60 is firmly attached to the upper surface of the graphite disk 10.

[0054] In other embodiments, the gas supply device 40 may further include a plurality of gas pipelines 41, which are arranged in parallel, and the gas outlet ends of the plurality of gas pipelines 41 are aligned with the airflow space 201, providing a high-speed airflow in the airflow space, and making the pressure on the lower surface of the substrate 60 less than the pressure on the upper surface through the Bernoulli effect, thereby making the substrate 60 firmly attached to the upper surface of the graphite disk 10.

[0055] It should be noted that the gas outlet end of the gas pipeline 41 is the end close to the gas flow space 201. Figure 1 In the figure, the gas outlet end of the gas pipeline 41 is the right end. The material of the gas pipeline 41 can be high temperature resistant quartz, or a graphite piece of the same material as the growth chamber.

[0056] In some embodiments of the present application, a flow regulating valve (not shown) and a shut-off valve (not shown) are provided on the gas pipeline 41. The flow regulating valve is used to regulate the gas flow in the gas pipeline 41, and the shut-off valve is used to control the on and off of the gas in the gas pipeline 41.

[0057] In the embodiment of the present application, the flow regulating valve is used to adjust the gas flow in the gas pipeline 41, and then adjust the flow rate of the gas, and can be adjusted according to the quality of different substrates 60 or the flow rate of different growth gases above the substrate 60, so that the device for suppressing white spots on the back of the wafer during the epitaxial growth process provided in the embodiment of the present application is more universal.

[0058] In some embodiments of the present application, Figure 1 and Figure 6 As shown, the device for suppressing white spots on the back of the wafer during the epitaxial growth process also includes a graphite ring 50, which is arranged on the upper part of the graphite disk 10, and the graphite ring 50 has a receiving hole 51 arranged along the first direction X. The substrate 60 is arranged in the receiving hole 51, and the graphite ring 50 is used to limit the circumferential movement of the substrate 60.

[0059] In the embodiment of the present application, since the graphite ring 50 is arranged on the upper part of the graphite disk 10 and the substrate 60 is arranged in the receiving hole 51 of the graphite disk 10, the inner side wall of the graphite ring 50 can circumferentially restrict the substrate 60 to prevent the substrate 60 from detaching from the graphite disk 10 during rotation, thereby improving the safety and reliability of the device for suppressing white spots on the back of the wafer during the epitaxial process.

[0060] In some embodiments of the present application, Figure 1 and Figure 6 As shown, the accommodating hole 51 of the graphite ring 50 includes a first hole segment 511 and a second hole segment 512, and the aperture of the first hole segment 511 is smaller than the aperture of the second hole segment 512; the graphite ring 50 can overlap the upper surface of the graphite disk 10, and the top part of the graphite disk 10 is located in the second hole segment 512, and the substrate 60 is placed in the first hole segment 511.

[0061] In the embodiment of the present application, the second hole section 512 is disposed on a side of the first hole section 511 close to the cyclone tray 20, that is, the second hole section 512 is located at the lower part of the first hole section 511. Figure 6 As shown, since the aperture of the first hole segment 511 is smaller than the aperture of the second hole segment 512, the longitudinal section of the graphite ring 50 is stepped, and the lower surface of the first step overlaps the upper surface of the graphite disk 10, so as to realize the connection between the graphite ring 50 and the graphite disk 10. The substrate 60 is arranged in the first hole segment 511, and the inner wall of the first hole segment 511 realizes the circumferential restriction of the substrate 60. In other words, through the above arrangement, the structure of the graphite ring 50 is cleverly used so that the graphite ring 50 can realize both the connection with the graphite disk 10 and the circumferential restriction of the substrate 60. In addition, the structure of the graphite ring 50 is simple, easy to manufacture, and can reduce the manufacturing cost.

[0062] An embodiment of the second aspect of the present application provides a method for suppressing white spots on the back of a wafer during epitaxial growth, comprising:

[0063] A high-speed airflow is introduced into the airflow space 201 formed between the graphite disk 10 having the through-type air holes 11 and the cyclone tray 20 through the gas supply device 40, so that the pressure on the lower surface of the substrate 60 is lower than the pressure on the upper surface of the substrate 60, thereby allowing the substrate 60 to be adsorbed on the graphite disk 10.

[0064] In the embodiment of the present application, a support frame 30 is provided between the graphite disk 10 and the cyclone tray 20. By setting the support member 30, a gap is left between the cyclone tray 20 and the graphite disk 10 to form an air flow space 201 for gas to pass through, and the graphite disk 10 is provided with a through-type pore 11, and the air flow space 201 is connected to the through-type pore 11. That is to say, the substrate 60 is placed on the graphite disk 10, and since the graphite disk 10 is provided with the through-type pore 11, the substrate 60 can be exposed through the through-type pore 11. The gas supply device 40 is used to provide a high-speed airflow into the airflow space 201 between the graphite disk 10 and the cyclone tray 20. The force of the high-speed airflow can act on the substrate 60 through the through-type air holes 11. That is to say, under the action of the high-speed airflow, the pressure on the lower surface of the substrate 60 on the graphite disk 10 can be made smaller than the pressure on the upper surface of the substrate 60, thereby generating a Bernoulli effect, so that the substrate 60 can be more firmly adsorbed on the graphite disk 10, and the substrate 60 and the graphite disk 10 can be fully fitted, thereby reducing the probability of the epitaxial growth gas contacting the carbon surface of the substrate, solving the problem of the epitaxial-related gas entering the carbon surface of the substrate to react and produce white mist anomalies and generate other crystal forms, and can also optimize the flatness of the epitaxial wafer, thereby improving the yield of the epitaxial wafer.

[0065] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0066] The above description is only a preferred embodiment of the present application and is not intended to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application are included in the protection scope of the present application.

Claims

1. A device for suppressing white spots on the back of a wafer during epitaxy, characterized in that: include: A graphite disk (10), the top of which is used to place a substrate (60), the graphite disk (10) being provided with through-type pores (11), the pores (11) being arranged along a first direction (X), the first direction (X) being the height direction of the device for suppressing white spots on the back of a wafer during epitaxy; A cyclone tray (20), the cyclone tray (20) being arranged at the bottom of the graphite tray (10), and the cyclone tray (20) being rotatable; a support member (30), the support member (30) being disposed between the graphite disk (10) and the cyclone tray (20), and being used to support the graphite disk (10), so that an airflow space (201) is formed between the graphite disk (10) and the cyclone tray (20), the airflow space (201) being in communication with the air hole (11); and the cyclone tray (20) can drive the graphite disk (10) to rotate through the support member (30); A gas supply device (40), the gas supply device (40) being used to generate an airflow into the airflow space (201) so that the pressure on the lower surface of the substrate (60) is lower than the pressure on the upper surface of the substrate (60).

2. The device for suppressing white spots on the back of a wafer during epitaxial growth according to claim 1, characterized in that: The support member (30) comprises a plurality of support columns (31), wherein the plurality of support columns (31) are fixedly connected to a side of the graphite disk (10) close to the cyclone tray (20), and a plurality of slots (32) are provided on a side of the cyclone tray (20) close to the graphite disk (10), wherein positions of the slots (32) correspond to positions of the support columns (31), and an end of the support column (31) away from the graphite disk (10) is placed in the slot (32) of the cyclone tray (20).

3. The device for suppressing white spots on the back of a wafer during epitaxial growth according to claim 1, characterized in that: The support member (30) comprises a plurality of support columns (31), wherein the plurality of support columns (31) are fixedly connected to a side of the cyclone tray (20) close to the graphite disk (10), and a slot (32) is provided on a side of the graphite disk (10) close to the cyclone tray (20), wherein the position of the slot (32) corresponds to the position of the support column (31), and an end of the support column (31) away from the cyclone tray (20) is placed in the slot (32) of the graphite disk (10).

4. The device for suppressing white spots on the back of a wafer during epitaxial growth according to claim 2 or 3, characterized in that: The cross-sectional shape of the support column (31) is adapted to the cross-sectional shape of the clamping groove (32).

5. The device for suppressing white spots on the back of a wafer during epitaxial growth according to claim 2 or 3, characterized in that: The plurality of support columns (31) are evenly distributed along the circumferential direction.

6. The device for suppressing white spots on the back of a wafer during epitaxial growth according to claim 1, characterized in that: The number of the pores (11) is multiple, and the multiple pores (11) are distributed in a radial manner on the graphite disk (10).

7. The device for suppressing white spots on the back of a wafer during epitaxial growth according to claim 1, characterized in that: The gas supply device (40) comprises a gas pipeline (41), and a gas outlet end of the gas pipeline (41) is aligned with the gas flow space (201).

8. The device for suppressing white spots on the back of a wafer during epitaxial growth according to claim 7, characterized in that: The gas pipeline (41) is provided with a flow regulating valve and a shutoff valve, wherein the flow regulating valve is used to regulate the gas flow in the gas pipeline (41), and the shutoff valve is used to control the on-off of the gas in the gas pipeline (41).

9. The device for suppressing white spots on the back of a wafer during epitaxial growth according to any one of claims 6 to 8, characterized in that: The device for suppressing white spots on the back of a wafer during epitaxy further comprises a graphite ring (50), the graphite ring (50) being arranged on the upper part of the graphite disk (10), the graphite ring (50) having a receiving hole (51) arranged along the first direction (X), the substrate (60) being arranged in the receiving hole (51), the graphite ring (50) being used to limit the circumferential movement of the substrate (60); the receiving hole (51) of the graphite ring (50) comprising a first hole segment (511) and a second hole segment (512), the aperture of the first hole segment (511) being smaller than the aperture of the second hole segment (512); The graphite ring (50) can overlap the upper surface of the graphite disk (10), and the top portion of the graphite disk (10) is located in the second hole section (512), and the substrate (60) is placed in the first hole section (511).

10. A method for suppressing white spots on the back of a wafer during epitaxy, characterized in that: include: A high-speed airflow is introduced into an airflow space (201) formed between a graphite disk (10) having through-type air holes (11) and a cyclone tray (20) through a gas supply device (40), so that the pressure on the lower surface of the substrate (60) is lower than the pressure on the upper surface of the substrate (60), thereby allowing the substrate (60) to be adsorbed on the graphite disk (10).

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