An apparatus and method for suppressing white spots on the back of wafers during epitaxy.

Abstract

This application provides an apparatus and method for suppressing white spots on the back of a wafer during epitaxy. The apparatus for suppressing white spots on the back of a wafer during epitaxy is optimized. The apparatus includes a graphite disk, a cyclone tray, a support, and a gas supply device. The top of the graphite disk is used to place the substrate, and the graphite disk has through-holes. The cyclone tray is located at the bottom of the graphite disk. The support supports the graphite disk, creating an airflow space between the graphite disk and the cyclone tray, which is connected to the holes. The cyclone tray can rotate the graphite disk via the support. The gas supply device generates airflow into the airflow space, making the pressure on the lower surface of the substrate lower than the pressure on the upper surface, generating a Bernoulli effect. This ensures the substrate and the graphite disk are fully bonded, reducing the probability of epitaxial growth gas contacting the lower surface of the substrate. This solves the problem of white fogging on the back side caused by epitaxial gas entering the carbon surface of the substrate and participating in the reaction, thereby improving the yield of the epitaxial wafer.

Description

Technical Field

[0001] This application relates to the field of silicon carbide epitaxial growth technology, and in particular to an apparatus and method for suppressing white spots on the back of a wafer during epitaxy. Background Technology

[0002] Silicon carbide (SiC) is a third-generation semiconductor material that has found applications in smart grids, electric vehicles, rail transportation, switching power supplies, industrial motors, and home appliances, showing promising development prospects. Unlike traditional silicon power device fabrication processes, silicon carbide power devices cannot be directly fabricated on silicon carbide single-crystal materials. Instead, high-quality epitaxial materials must be grown on a conductive single-crystal substrate, and various devices are then manufactured on the epitaxial layer.

[0003] Currently, during the silicon carbide epitaxial growth process, issues such as white haze-like abnormalities on the substrate carbon surface, formation of other crystal types, and deterioration of epitaxial wafer flatness are prone to occur, leading to a decrease in epitaxial wafer yield. Summary of the Invention

[0004] The purpose of this application is to provide an apparatus and method for suppressing white spots on the back side of a wafer during epitaxy, thereby solving the problems of white haze abnormalities on the carbon surface of the substrate, as well as the formation of other crystal types and deterioration of the flatness of the epitaxial wafer. The specific technical solution is as follows:

[0005] An embodiment of the first aspect of this application provides an apparatus for suppressing white spots on the back of a wafer during epitaxy. The apparatus includes: 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 has through-holes, which are arranged along a first direction, the first direction being the height direction of the apparatus for suppressing white spots on the back of the wafer during epitaxy. The cyclone tray is disposed at the bottom of the graphite disk and is rotatable. The support member is disposed between the graphite disk and the cyclone tray to support the graphite disk, thereby forming an airflow space between the graphite disk and the cyclone tray. The airflow space is connected to the through-holes. The cyclone tray can drive the graphite disk to rotate through the support member. The gas supply device generates 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 includes a plurality of support columns, which are fixedly connected to the side of the graphite disk near the cyclone tray. The side of the cyclone tray near the graphite disk is provided with a plurality of slots, the positions of which correspond to the positions of the support columns. The 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 includes a plurality of support columns, which are fixedly connected to the side of the cyclone tray near the graphite disk. The side of the graphite disk near the cyclone tray is provided with a slot, the position of which corresponds to the position of the support column. The 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 the 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 conduit with its outlet aligned with the airflow space.

[0012] In some embodiments, the gas pipeline is provided with a flow regulating valve and a shut-off valve. The flow regulating valve is used to regulate the gas flow rate 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 epitaxy further includes a graphite ring disposed on the upper part of the graphite disk. The graphite ring has a receiving hole disposed along the first direction, and the substrate is disposed within the receiving hole. The graphite ring is used to restrict the circumferential movement of the substrate. The receiving hole of the graphite ring includes a first hole segment and a second hole segment, the diameter of the first hole segment being smaller than the diameter 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 within the second hole segment, while the substrate is placed within the first hole segment.

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

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

[0016] Beneficial effects of the embodiments in this application:

[0017] The device for suppressing white spots on the back of wafers during epitaxy provided in this application embodiment, by setting a support member, leaves a gap between the cyclone tray and the graphite disk to form an airflow space for gas passage, and the graphite disk is provided with through-holes, the airflow space being connected to the through-holes. A gas supply device is used to provide high-speed airflow into the airflow space between the graphite disk and the cyclone tray, enabling the pressure on the lower surface of the substrate on the graphite disk to be less than the pressure on the upper surface of the substrate, generating a Bernoulli effect. This allows the substrate to be more firmly adsorbed onto the graphite disk, achieving full adhesion between the substrate and the graphite disk, thereby reducing the probability of epitaxial growth gas contacting the carbon surface of the substrate. This solves the problems of white fog-like abnormalities and the formation of other crystal forms caused by the reaction of epitaxial gases with the carbon surface of the substrate, optimizes the flatness of the epitaxial wafer, and thus improves the yield of the epitaxial wafer.

[0018] Of course, implementing any product or method of this application does not necessarily require achieving all of the advantages described above at the same time. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application 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 some embodiments of this application. For those skilled in the art, other embodiments can be obtained based on these drawings.

[0020] Figure 1 An exploded perspective view of the apparatus and substrate for suppressing white spots on the back of a wafer during epitaxy, as provided in an embodiment of this application.

[0021] Figure 2 for Figure 1 An exploded view of the device for suppressing white spots on the back of the wafer during epitaxy.

[0022] Figure 3 for Figure 1 An axial view of the device shown for suppressing white spots on the back of the wafer during epitaxy;

[0023] Figure 4 for Figure 1 The device for suppressing white spots on the back of the wafer during epitaxy and the substrate are shown in an axial view.

[0024] Figure 5 A perspective view of the apparatus for suppressing white spots on the back of a wafer during epitaxy and the substrate after mounting, provided in an embodiment of this application.

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

[0026] Figure 7This is a schematic diagram of the device for suppressing white spots on the back of the wafer during epitaxy and the simulation results inside the growth chamber, provided in the embodiments of this application.

[0027] Figure 8 for Figure 7 The diagram shown is an enlarged view of the device used to suppress white spots on the back of the wafer during epitaxy, as illustrated in the simulation results diagram.

[0028] Figure label:

[0029] Graphite disk 10; vent 11; cyclone tray 20; airflow space 201; support 30; support column 31; slot 32; gas supply device 40; gas pipe 41; graphite ring 50; receiving hole 51; first hole section 511; second hole section 512; substrate 60; warm color scheme 71; transitional color scheme 72; cool color scheme 73;

[0030] First direction X. Detailed Implementation

[0031] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art based on this application are within the scope of protection of this application.

[0032] Currently, in the silicon carbide epitaxial growth process, the substrate is placed within a graphite disk of appropriate size, and epitaxial growth is carried out in a specific environment. The adhesion between the substrate and the graphite disk is entirely due to the substrate's own weight. However, due to the difference in doping concentration between the substrate and the epitaxial wafer, as the epitaxial thickness increases, the facet size gradually increases, and the adhesion gap between the wafer and the graphite disk widens. This allows epitaxial gases to enter the carbon surface of the substrate, resulting in anomalies such as white spots, white haze, and the formation of other crystal forms. Furthermore, as the facet size increases, the adhesion between the wafer and the graphite disk deteriorates, and the radial temperature field distribution becomes more uneven, further worsening the flatness of the epitaxial wafer. It should be noted that the substrate is the raw material for growth; substrate growth (after epitaxy) is called an epitaxial wafer, also known as a crystal wafer. The back side of the wafer is the carbon surface, which is... Figure 1 The lower surface of the middle substrate 60.

[0033] An embodiment of the first aspect of this 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 a wafer during epitaxy includes: a graphite disk 10, a cyclone tray 20, a support member 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 through-holes 11, which are arranged along a first direction X, which is the height direction of the device for suppressing white spots on the back of the wafer during epitaxy. The cyclone tray 20 is located at the bottom of the graphite disk 10 and can drive the graphite disk 10 to rotate. The support member 30 is located between the graphite disk 10 and the cyclone tray 20 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 is connected to the air hole 11. The cyclone tray 20 can drive the graphite disk 10 to rotate through the support member 30. The gas supply device 40 is used to generate 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 a wafer during epitaxy provided in this application embodiment provides a support member 30 so that a gap is left between the cyclone tray 20 and the graphite disk 10, forming an airflow space 201 for gas passage. The graphite disk 10 is provided with through-holes 11, and the airflow space 201 is connected to the through-holes 11. That is, when the substrate 60 is placed on the graphite disk 10, the substrate 60 can be exposed through the through-holes 11 because the graphite disk 10 is provided with through-holes 11. The gas supply device 40 provides 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-hole 11. That is, under the action of the high-speed airflow, the pressure on the lower surface of the substrate 60 on the graphite disk 10 is less than the pressure on the upper surface of the substrate 60, generating the Bernoulli effect. This allows the substrate 60 to be more firmly adsorbed on the graphite disk 10, achieving full adhesion between the substrate 60 and the graphite disk 10. This reduces the probability of epitaxial growth gas contacting the carbon surface of the substrate, solves the problem of white fog-like abnormalities and the formation of other crystal forms caused by the reaction of epitaxial gases with the carbon surface of the substrate. It 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 embodiments of this application provide a schematic diagram of the device for suppressing white spots on the back of the wafer during epitaxy and the simulation results within the growth cavity, which is also a schematic diagram of the device for suppressing white spots on the back of the wafer during epitaxy and the pressure distribution within the growth cavity; wherein... Figure 7 The left side shows the color scheme corresponding to the standard pressure distribution; Figure 8 for Figure 7 The diagram shown is an enlarged view of the device used to suppress white spots on the back of the wafer during epitaxy, as illustrated in the simulation results. Figure 3and Figure 5 Taking the left-side air intake as an example, according to the simulation results, due to the left-side air intake, 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. Because the high-speed airflow acts on the airflow space 201, the pressure value on the upper surface of the substrate 60 on the graphite disk 10 is greater than the pressure value on the lower surface of the substrate 60. That is to say, in the simulation results, the pressure value on the upper surface of the substrate 60 is a warm color 71, the middle position of the substrate 60 is a transitional color 72, and the pressure value on the lower surface of the substrate 60 is a cool color 73. Therefore, the simulation results show that the Bernoulli effect can be generated, which makes the substrate 60 more firmly adsorbed on the graphite disk 10, realizing the full adhesion between the substrate 60 and the graphite disk 10, thereby reducing the probability of epitaxial growth gas contacting the carbon surface of the substrate.

[0036] It should be noted that warm color 71 represents positive pressure, and the darker the color in warm color 71, the greater the pressure. For example, the pressure value at red is greater than that at yellow. Transitional color 72 represents slight positive pressure, which is less than the pressure at warm color 71. Cool color 73 represents negative pressure, and the darker the cool color, the greater the negative pressure. For example, the negative pressure at dark blue is greater than that at light blue. In other words, there is a negative pressure between the graphite disk 10 and the substrate 60, and a relatively large positive pressure on the upper surface of the substrate 60, which allows the substrate 60 to adhere only to the graphite disk 10. In practical applications, the gas supply device 40 can provide high-speed airflow into the airflow space 201 between the graphite disk 10 and the cyclone tray 20 in other directions, such as the right side. This application does not limit the air intake direction.

[0037] The embodiments of this application achieve unexpected technical effects with a simple structure. They solve the problems of white fog-like abnormalities caused by the reaction of epitaxial gases with the carbon surface of the substrate and the formation of other crystal forms in the prior art. They can also optimize the flatness of the epitaxial wafer, thereby improving the yield of the epitaxial wafer. They have outstanding substantive features and significant progress.

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

[0039] It should be noted that the device for suppressing white spots on the back of the wafer during epitaxy is applied in the silicon carbide epitaxial growth environment. During the silicon carbide epitaxial growth process, the upper surface of the substrate 60, which 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 pneumatically driven rotating tray; the rotation of the cyclone tray 20 drives the graphite disk 10 to rotate. Alternatively, other rotatable trays can be used instead of the cyclone tray 20.

[0041] In practical applications, silicon carbide epitaxial growth is often carried out in a growth chamber (not shown). The graphite disk 10, cyclone tray 20, and support 30 are placed inside the growth chamber, and the gas supply device 40 can be located on the side wall of the growth chamber. When the gas supply device 40 is a gas pipe 41, a through hole can be provided on the side wall of the growth chamber, through which the gas pipe 41 extends into the growth chamber, and the gas outlet is aligned with the gap between the graphite disk 10 and the cyclone tray 20. Devices for suppressing white spots on the back of the wafer during epitaxy often also include a growth gas supply device (not shown), which is used to supply growth gas to the upper surface of the substrate 60. According to the Bernoulli effect, the higher the flow velocity of the fluid, the lower the pressure. The flow velocity of the high-speed gas flow provided by the gas supply device 40 into the gas flow space 201 is greater than the flow velocity of the growth gas 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 to the right of the gas supply device 40 indicates the direction of the high-speed airflow. In this embodiment, the flow rate of the high-speed airflow is not limited. If the flow rate of the high-speed airflow provided by the gas supply device is greater than the flow rate of the growth gas above the substrate 60, 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 enabling the substrate 60 to be tightly adsorbed on the graphite disk.

[0042] In some embodiments of this application, such as Figures 1 to 4 As shown, the support member 30 includes multiple support columns 31, which are fixedly connected to the side of the graphite disk 10 near the cyclone tray 20. The side of the cyclone tray 20 near the graphite disk 10 is provided with multiple slots 32, the positions of which 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 this embodiment, since the support column 31 is connected to the graphite disk 10, the graphite disk 10 is connected to the cyclone tray 20 via the support column 31, and the support column 31 supports the graphite disk 10, thereby forming an airflow space between the graphite disk 10 and the cyclone tray 20 for high-speed airflow to pass through. 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 side wall of the support column 31 abuts against the inner side wall of the slot 32, so that the cyclone tray 20 drives the graphite disk 10 to rotate via the support member 30.

[0044] In some embodiments of this application, the support member 30 includes a plurality of support columns 31, which are fixedly connected to the side of the cyclone tray 20 near the graphite disk 10. The side of the graphite disk 10 near the cyclone tray 20 is provided with a slot 32, the position of the slot 32 corresponding to the position of the support column 31, and 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 this embodiment, since the support column 31 is connected to the cyclone tray 20, the graphite disk 10 is connected to the cyclone tray 20 via the support column 31, and the support column 31 supports the graphite disk 10, so that an airflow space is formed between the graphite disk 10 and the cyclone tray 20 for high-speed airflow to pass through. 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 side wall of the support column 31 abuts against the inner side wall of the slot 32, so that the cyclone tray 20 drives the graphite disk 10 to rotate via the support member 30.

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

[0047] In some embodiments of this application, such as Figures 1 to 4 As shown, the cross-sectional shape of the support column 31 matches the cross-sectional shape of the slot 32. For example, the support column 31 is cylindrical, and the slot 32 is circular. Since the support column 31 is circular and the slot 32 is also circular, there are no requirements for the assembly direction when placing the support column 31 into the slot 32, which can reduce assembly time.

[0048] In some embodiments of this application, multiple support columns 31 are evenly distributed along the circumferential direction. Because the multiple support columns 31 are evenly distributed along the circumferential direction of the graphite disk 10, the graphite disk 10 and the cyclone tray 20 are subjected to more uniform and stable forces, thereby improving the stability of the device during operation and ensuring that the graphite disk 10 is stably supported above the cyclone tray 20. For example, the number of support columns 31 can be three, and the projection of the three support columns 31 onto the graphite disk 10 forms an equilateral triangle.

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

[0050] In this embodiment of the application, the number of pores 11 is multiple, such as... Figure 3As shown, multiple pores 11 are arranged side-by-side at intervals to form pore rows, and these pore rows are intersected, causing the pores 11 to radiate outward from the center of the graphite disk 10. Furthermore, the pores 11 closer to the center of the graphite disk 10 are more densely packed, allowing the Bernoulli effect to fully act on the center of the substrate 60 on the graphite disk 10. This arrangement improves the uniformity of the pore distribution, enabling the Bernoulli effect to act better on the substrate 60, resulting in a tighter fit between the substrate 60 and the graphite disk 10.

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

[0052] In some embodiments of this application, the gas supply device 40 includes a gas conduit 41, the outlet of which is aligned with the airflow space 201.

[0053] In the embodiments of this application, such as Figures 1 to 3 As shown, the gas pipe 41 is a planar gas pipe, and the width of the gas pipe 41 can be equal to the distance between the two farthest gas holes 11 on the graphite disk 10. The outlet end of the planar gas pipe is aligned with the airflow space 201, providing a high-speed airflow to the airflow space 201. Through the Bernoulli effect, the pressure on the lower surface of the substrate 60 is less than the pressure on the upper surface, thereby making the substrate 60 firmly attached to the upper surface of the graphite disk 10.

[0054] In other embodiments, the gas supply device 40 may also include multiple gas pipes 41 arranged in parallel, with the outlet ends of the multiple gas pipes 41 aligned with the airflow space 201 to provide high-speed airflow to the airflow space. Through the Bernoulli effect, the pressure on the lower surface of the substrate 60 is less than the pressure on the upper surface, thereby making the substrate 60 firmly attached to the upper surface of the graphite disk 10.

[0055] It should be noted that the outlet end of the gas pipe 41 is the end closest to the airflow space 201. Figure 1 In the middle, the gas outlet of gas pipe 41 is on the right. The material of gas pipe 41 can be high-temperature resistant quartz or graphite of the same material as the growth chamber.

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

[0057] In this embodiment, the flow regulating valve is used to regulate the gas flow rate in the gas pipeline 41, thereby regulating the gas flow rate. This allows for adjustment based on the different qualities of the substrate 60 or the different flow rates of the growth gas above the substrate 60, making the device for suppressing white spots on the back of the wafer during epitaxy provided in this embodiment more universal.

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

[0059] In this embodiment, since the graphite ring 50 is disposed on the upper part of the graphite disk 10 and the substrate 60 is disposed in the receiving hole 51 of the graphite disk 10, the inner sidewall of the graphite ring 50 can circumferentially restrict the substrate 60, preventing 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 epitaxy.

[0060] In some embodiments of this application, such as Figure 1 and Figure 6 As shown, the receiving hole 51 of the graphite ring 50 includes a first hole segment 511 and a second hole segment 512. The diameter of the first hole segment 511 is smaller than the diameter 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, while the substrate 60 is placed in the first hole segment 511.

[0061] In this embodiment, the second hole segment 512 is located on the side of the first hole segment 511 near the cyclone tray 20, that is, the second hole segment 512 is located below the first hole segment 511. Figure 6 As shown, because the diameter of the first aperture segment 511 is smaller than that of the second aperture segment 512, the longitudinal section of the graphite ring 50 is stepped. The lower surface of the first step overlaps the upper surface of the graphite disk 10, thus connecting the graphite ring 50 and the graphite disk 10. The substrate 60 is disposed within the first aperture segment 511, and the inner wall of the first aperture segment 511 provides circumferential confinement to the substrate 60. In other words, through the above arrangement, the structure of the graphite ring 50 cleverly enables it to both connect to the graphite disk 10 and provide circumferential confinement to the substrate 60. Furthermore, the graphite ring 50 has a simple structure, is easy to manufacture, and can reduce manufacturing costs.

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

[0063] A high-speed airflow is introduced into the airflow space 201 formed between the graphite disk 10 with through-hole vent 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 less than the pressure on the upper surface of the substrate 60, thereby causing the substrate 60 to be adsorbed onto the graphite disk 10.

[0064] In this embodiment, a support frame 30 is provided between the graphite disk 10 and the cyclone tray 20. By providing the support frame 30, a gap is left between the cyclone tray 20 and the graphite disk 10, forming an airflow space 201 for gas to pass through. The graphite disk 10 is provided with a through-hole 11, and the airflow space 201 is connected to the through-hole 11. That is to say, the substrate 60 is placed on the graphite disk 10, and since the graphite disk 10 is provided with a through-hole 11, the substrate 60 can be exposed through the through-hole 11. The gas supply device 40 provides 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-hole 11. That is, under the action of the high-speed airflow, the pressure on the lower surface of the substrate 60 on the graphite disk 10 is less than the pressure on the upper surface of the substrate 60, generating the Bernoulli effect. This allows the substrate 60 to be more firmly adsorbed on the graphite disk 10, achieving full adhesion between the substrate 60 and the graphite disk 10. This reduces the probability of epitaxial growth gas contacting the carbon surface of the substrate, solves the problem of white fog-like abnormalities and the formation of other crystal forms caused by the reaction of epitaxial gases with the carbon surface of the substrate. It 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 document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0066] The above description is merely a preferred embodiment of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application are included within the scope of protection of this 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) is provided with a substrate (60) on top. The graphite disk (10) is provided with through-holes (11). The holes (11) are arranged along a first direction (X). The first direction (X) is the height direction of the device for suppressing white spots on the back of the wafer during epitaxy. Cyclone tray (20), the cyclone tray (20) is disposed at the bottom of the graphite disk (10), and the cyclone tray (20) is rotatable; A support member (30) is disposed between the graphite disk (10) and the cyclone tray (20) 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 connected to 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) is used to generate airflow into the airflow space (201) 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).

2. The apparatus for suppressing white spots on the back of a wafer during epitaxy according to claim 1, characterized in that, The support member (30) includes multiple support columns (31), which are fixedly connected to the side of the graphite disk (10) near the cyclone tray (20). The side of the cyclone tray (20) near the graphite disk (10) is provided with multiple slots (32), the position of the slots (32) corresponds to the position of the support columns (31), and the 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 apparatus for suppressing white spots on the back of a wafer during epitaxy according to claim 1, characterized in that, The support member (30) includes a plurality of support columns (31), which are fixedly connected to the side of the cyclone tray (20) near the graphite disk (10). The side of the graphite disk (10) near the cyclone tray (20) is provided with a slot (32), the position of the slot (32) corresponds to the position of the support column (31), and the 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 apparatus for suppressing white spots on the back of a wafer during epitaxy 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 slot (32).

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

6. The apparatus for suppressing white spots on the back of a wafer during epitaxy according to claim 1, characterized in that, The number of pores (11) is multiple, and the multiple pores (11) are radially distributed on the graphite disk (10).

7. The apparatus for suppressing white spots on the back of a wafer during epitaxy according to claim 1, characterized in that, The gas supply device (40) includes a gas pipe (41) with the outlet end of the gas pipe (41) aligned with the airflow space (201).

8. The apparatus for suppressing white spots on the back of a wafer during epitaxy according to claim 7, characterized in that, The gas pipeline (41) is equipped with a flow regulating valve and a shut-off valve. The flow regulating valve is used to regulate the gas flow rate in the gas pipeline (41), and the shut-off valve is used to control the on / off of the gas in the gas pipeline (41).

9. The apparatus for suppressing white spots on the back of a wafer during epitaxy according to any one of claims 6-8, characterized in that, The device for suppressing white spots on the back of the wafer during epitaxy further includes a graphite ring (50), which is disposed on the upper part of the graphite disk (10). The graphite ring (50) has a receiving hole (51) disposed along the first direction (X). The substrate (60) is disposed in the receiving hole (51). The graphite ring (50) is used to restrict the circumferential movement of the substrate (60). The receiving hole (51) of the graphite ring (50) includes a first hole segment (511) and a second hole segment (512). The diameter of the first hole segment (511) is smaller than the diameter 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).

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 the airflow space (201) formed between the graphite disk (10) with through-hole (11) and the cyclone tray (20) by the gas supply device (40), 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), thereby causing the substrate (60) to be adsorbed onto the graphite disk (10).

Images