Epitaxial growth base and epitaxial growth equipment with same

Abstract

The utility model discloses an epitaxial growth base and epitaxial growth equipment with the same, and relates to the technical field of semiconductors, and the epitaxial growth base comprises a bearing part and an edge part. The edge part is of an annular structure and surrounds the peripheral side of the bearing part, a containing groove is defined by the edge part and the bearing part on one side of the bearing part, the containing groove is used for containing a substrate, a plurality of grooves are formed in the peripheral wall of the edge part in the circumferential direction of the edge part at intervals, and the grooves are formed in the axial direction of the edge part. The grooves and the end faces of the two ends of the edge part are arranged at intervals. According to the epitaxial growth base, the flatness level of the substrate on the epitaxial layer can be improved.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductors, in particular to an epitaxial growth base and an epitaxial growth device having the same. Background Art

[0002] In the current manufacturing process of wafer original substrates, epitaxial growth is an important process in semiconductor manufacturing. This process is a method of growing a single crystal layer that meets the requirements on the substrate by controlling the flow rates of reaction gases and carrier gases under specific temperature and pressure conditions. Specific methods include vacuum epitaxy, vapor phase epitaxy, liquid phase epitaxy, etc.

[0003] For the epitaxial layer of a silicon wafer, its flatness parameter is an important parameter affecting the performance of the silicon wafer. For example, for 12-inch epitaxial products entering the stage of small line widths, small line widths require a higher flatness for the epitaxial wafer; while a lower flatness level of the epitaxial layer will affect the processing of subsequent wafer devices, easily cause device failures, and reduce the product yield.

[0004] Currently, the most widely used is chemical vapor deposition epitaxy. However, the crystal growth rates of silicon wafers (or epitaxial wafers) are different in different crystal orientations, which has a greater impact on the growth rate at the edge of the silicon wafer, such as at 120 mm - 150 mm, and will reduce the edge flatness ESFQR (Edge Site Front Ouadratic Rang) level. Summary of the Utility Model

[0005] The utility model aims to at least solve one of the technical problems existing in the prior art. For this purpose, the utility model provides an epitaxial growth base, and the epitaxial growth base can improve the flatness level of the substrate in the epitaxial layer.

[0006] The utility model also provides an epitaxial growth device having the above epitaxial growth base.

[0007] The epitaxial growth base according to the first aspect embodiment of the utility model includes: a bearing part; an edge part, the edge part is formed as an annular structure and is arranged around the outer peripheral side of the bearing part, and defines a receiving groove with the bearing part on one side of the bearing part for placing a substrate. A plurality of grooves are formed on the outer peripheral wall of the edge part and are spaced along the circumferential direction of the edge part. In the axial direction of the edge part, the grooves are respectively spaced from the two end faces of the edge part.

[0008] According to the epitaxial growth pedestal of the embodiment of the present utility model, by providing a groove on the outer peripheral wall of the edge portion, it is beneficial to increase the heat dissipation area of the epitaxial growth pedestal at the groove position, which is beneficial to reducing the temperature of the silicon wafer corresponding to the groove position. When the silicon wafer is placed in the receiving groove, the crystal orientation with a relatively fast epitaxial growth rate of the silicon wafer can be set corresponding to the groove, so as to reduce the temperature of the crystal orientation position of the silicon wafer corresponding to the groove, reduce the growth rate of the silicon wafer corresponding to the groove position, thereby reducing the difference in the growth rates of the silicon wafer in different crystal orientations, and then the flatness level of the edge of the silicon wafer can be improved, and the yield of the subsequent devices can be enhanced.

[0009] In some embodiments, from the central position of the groove in the circumferential direction towards both circumferential sides, the depth of the groove decreases.

[0010] In some embodiments, the outer peripheral contour of the edge portion is circular, and the bottom wall of the groove extends along a straight line.

[0011] In some embodiments, the thickness of the edge portion is greater than the thickness of the bearing portion. In the radial direction of the edge portion, the maximum depth of the groove is less than the radial width of the edge portion and greater than half of the radial width of the edge portion.

[0012] In some embodiments, the setting of the groove satisfies the condition: the radial width of the edge portion is w, the maximum depth of the groove is h, w≥36mm, 20mm≤h≤35mm.

[0013] In some embodiments, the thickness of the edge portion is t, and the minimum distance between the groove and the two end faces of the bearing portion is x, 4.5mm≤t≤8mm, 0.2mm≤x≤2mm.

[0014] In some embodiments, there are four grooves and they are arranged at equal intervals in the circumferential direction. In the cross-section of the edge portion, with the central axis of the edge portion as the center of the circle, the central angle corresponding to each groove is α, 50°≤α≤70°.

[0015] According to the epitaxial growth device of the second aspect embodiment of the present utility model, it includes a cooling structure and the epitaxial growth pedestal described in the above embodiment. The cooling structure is used to blow cooling gas towards a preset area, and the epitaxial growth pedestal is rotatably arranged so that the outer peripheral wall of the edge portion passes through the preset area.

[0016] According to the epitaxial growth device of the embodiments of the present utility model, by adopting the epitaxial growth base of the above embodiments, during the rotation of the epitaxial growth base, the cooling gas can exchange heat with the groove wall to take away more heat at the groove position, so as to reduce the temperature at the groove of the edge part, and further reduce the temperature at the edge of the substrate in the accommodation groove facing the groove in the outer circumference, so that the temperatures in different crystal orientations of the silicon wafer are different, so as to reduce the influence of the growth rates in different crystal orientations on the flatness, so as to achieve the purpose of improving the flatness level of the epitaxial layer.

[0017] In some embodiments, the cooling structure is configured such that: the blowing angle of the cooling structure is fixedly set or adjustable, and the blowing angle is between a first angle and a second angle. At the first angle, the cooling structure blows air flow along the direction tangent to the outer peripheral wall of the edge part. At the second angle, the cooling structure blows air flow towards the cylindrical surface where the deepest positions of the plurality of grooves are located; and / or, the blowing flow rate of the cooling structure is adjustable, and the blowing flow rate is within the range of 2 to 15 slm.

[0018] In some embodiments, from the central position of the groove in the circumferential direction towards both circumferential sides, the depth of the groove decreases. The blowing angle of the cooling structure is adjustable. The epitaxial growth device has a first mode and a second mode. In the first mode, the depth of the groove in the part of the edge part located within the preset area increases as the epitaxial growth base rotates, and the blowing angle deflects towards the second angle; in the second mode, the depth of the groove in the part of the edge part located within the preset area decreases as the epitaxial growth base rotates, and the blowing angle deflects towards the first angle.

[0019] The additional aspects and advantages of the present utility model will be partly given in the following description, partly will become obvious from the following description, or will be understood through the practice of the present utility model. Description of the Drawings

[0020] The above and / or additional aspects and advantages of the present utility model will become obvious and easy to understand from the description of the embodiments in conjunction with the following drawings, wherein:

[0021] Figure 1 is a schematic diagram of the crystal orientation of the silicon wafer;

[0022] Figure 2 is a schematic structural diagram of the epitaxial growth base according to the embodiments of the present utility model. The part with cross-hatching in the figure corresponds to the groove;

[0023] Figure 3 is Figure 2 a partial longitudinal sectional view of the epitaxial growth base of the illustrated embodiment;

[0024] Figure 4 is Figure 2 a schematic diagram of an epitaxial growth pedestal shown in Figure 2 containing a substrate, where the substrate is located at a preset position;

[0025] Figure 5 is a schematic structural diagram of a cooling structure of an epitaxial growth device according to an embodiment of the present invention with a blowing direction at a first angle;

[0026] Figure 6 is a schematic structural diagram of a cooling structure of an epitaxial growth device according to an embodiment of the present invention with a blowing direction at a second angle;

[0027] Figure 7 is Figure 2 a schematic diagram of the change in the groove depth corresponding to the angle of the epitaxial growth pedestal shown in Figure 2 , with the vertical being the ratio of the current position depth of the groove to the maximum depth of the groove;

[0028] Figure 8 is a schematic diagram of the thickness of a silicon wafer grown on an epitaxial growth pedestal without grooves in the prior art;

[0029] Figure 9 is a schematic diagram of the thickness of a silicon wafer grown on an epitaxial growth pedestal with grooves in an embodiment of the present application.

[0030] Reference numerals:

[0031] Epitaxial growth device 100,

[0032] Substrate 10, positioning notch 11,

[0033] Epitaxial growth pedestal 20, bearing part 21, edge part 22, groove 221, receiving groove 23,

[0034] Cooling structure 30. Detailed implementation manners

[0035] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present invention and should not be construed as limiting the present invention.

[0036] The following disclosure provides many different embodiments or examples for implementing different structures of the present utility model. To simplify the disclosure of the present utility model, components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present utility model. In addition, the present utility model may repeat reference numerals and / or letters in different examples. Such repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present utility model provides examples of various specific processes and materials, but those of ordinary skill in the art can realize the applicability of other processes and / or the use of other materials.

[0037] In the description of the embodiments of the present application, the term "and / or" is merely a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this article generally represents an "or" relationship between the associated objects before and after.

[0038] Next, with reference to the accompanying drawings, an epitaxial growth susceptor 20 and an epitaxial growth apparatus 100 according to an embodiment of the present utility model will be described.

[0039] It should be noted that the substrate 10 forms an epitaxial layer through epitaxial growth. During the epitaxial growth process of the substrate 10, the growth rate of the substrate 10 at different circumferential positions is affected by the crystal orientation of the substrate 10. That is to say, the crystal growth rates of the substrate 10 in different crystal orientations are different. For example, as Figure 1 shown, taking the substrate 10 as a silicon wafer as an example, the silicon wafer has <100> crystal orientations and <110> crystal orientations extending in the radial direction. A plurality of <100> crystal orientations and a plurality of <110> crystal orientations alternate one by one in the circumferential direction. Taking four <100> crystal orientations and four <110> crystal orientations as an example respectively, the four <110> crystal orientations correspond to four radial directions spaced 90° apart in the circumferential direction of the silicon wafer, and the four <100> crystal orientations correspond to another four radial directions spaced 90° apart in the circumferential direction of the silicon wafer. And the adjacent <110> crystal orientation and <100> crystal orientation are spaced 45° apart in the circumferential direction of the silicon wafer.

[0040] The crystal orientation of the silicon wafer is an important factor affecting its epitaxial growth rate at different circumferential positions. When the environmental conditions at different circumferential positions of the silicon wafer are the same, the growth rate of the silicon wafer in the <110> crystal orientation is the largest, and the growth rate in the <100> crystal orientation is the smallest. The growth rate of the silicon wafer at different circumferential positions gradually decreases from the <110> crystal orientation to the <100> crystal orientation, resulting in inconsistent growth rates of the silicon wafer at different circumferential positions and affecting the local flatness and edge flatness of its epitaxial layer.

[0041] Among them, the principle of the influence of the crystal orientation of the silicon wafer on the epitaxial growth rate at different positions thereof is well known to those skilled in the art and will not be elaborated herein.

[0042] In this application, the type of the substrate 10 is not limited. For the convenience of description, hereinafter, the substrate 10 is taken as an example of a silicon wafer for description. In this application, the epitaxial growth method of the silicon wafer is not limited. For example, the epitaxial growth of the silicon wafer is completed by vapor phase epitaxial deposition.

[0043] As Figure 2 and Figure 3 As shown, the epitaxial growth base 20 includes a bearing portion 21 and an edge portion 22. The edge portion 22 is formed as an annular structure and is disposed around the outer peripheral side of the bearing portion 21. The edge portion 22 and the bearing portion 21 define a receiving groove 23 on one side of the bearing portion 21. The receiving groove 23 is used to place the substrate 10. The above-mentioned one side surface of the bearing portion 21 may define the bottom wall of the receiving groove 23, and the inner peripheral wall of the edge portion 22 may define the peripheral wall of the receiving groove 23.

[0044] Among them, a plurality of grooves 221 are formed on the outer peripheral wall of the edge portion 22 and are arranged at intervals in the circumferential direction of the edge portion 22. In the axial direction of the edge portion 22, the grooves 221 are respectively spaced from the two end faces of the edge portion 22, so that the grooves 221 do not penetrate through the axial two end faces of the edge portion 22.

[0045] It can be understood that the epitaxial growth rate of the silicon wafer is affected by temperature. Generally, at a higher temperature, the automatic migration speed of silicon atoms is accelerated, which increases the crystal growth rate, while a lower temperature will slow down the growth rate of the silicon wafer. In the related art, the temperatures at the edges of the silicon wafer are basically the same, but the growth rates at different crystal orientation positions of the silicon wafer are different. The crystal orientation positions with a faster growth rate are thicker, and the crystal orientation positions with a slower growth rate are thinner, resulting in a lower flatness level of the epitaxial layer.

[0046] Specifically, as Figure 4 shown, the substrate 10 is placed at a preset position of the epitaxial growth base 20. At the preset position, the <110> crystal orientation of the substrate 10 is radially aligned with the groove 221 along the radial direction of the edge portion 22, and the <100> crystal orientation of the substrate 10 is staggered with the groove 221 in the circumferential direction of the edge portion 22, so that the <100> crystal orientation is radially aligned with the interval between two adjacent grooves 221.

[0047] The epitaxial growth base 20 of the embodiment of the present application is beneficial to increasing the heat dissipation area of ​​the epitaxial growth base 20 at the position of the groove 221 by setting the groove 221 on the outer peripheral wall of the edge portion 22, which is beneficial to reducing the temperature of the silicon wafer at the position corresponding to the groove 221. When the silicon wafer is placed in the receiving groove 23, the crystal orientation of the silicon wafer with a faster epitaxial growth rate can be set corresponding to the groove 221, so as to reduce the temperature of the silicon wafer at the crystal orientation position corresponding to the groove 221, reduce the growth rate of the silicon wafer at the position corresponding to the groove 221, thereby reducing the difference in the growth rate of the silicon wafer in different crystal orientations, and then can improve the flatness level at the edge of the silicon wafer, improve the ESFQR level at the edge of the silicon wafer, and improve the yield of the back-end device.

[0048] For example, during the epitaxial growth of a silicon wafer, cooling gas is introduced into the epitaxial chamber so that the cooling gas can flow through or blow toward the groove 221. The cooling gas can have a larger contact area with the edge portion 22 at the position of the groove 221, so that the cooling gas can take away more heat at the position of the groove 221, thereby reducing the temperature of the edge portion 22 at the groove 221, and further reducing the temperature of the silicon wafer in the receiving groove 23 at the periphery toward the edge of the groove 221, so that the temperature of the silicon wafer in different crystal directions is different, thereby reducing the influence of the growth rates in different crystal directions on the flatness.

[0049] The aforementioned radially extending <100> Crystal orientation and <110> Taking the silicon wafer with the same crystal orientation as an example, when the temperature at the edge of the silicon wafer is basically the same, <110> The growth rate is the largest at the crystal direction, making <110> The thickness is the largest at the crystal direction, and <100> The growth rate is the smallest everywhere in the crystal direction, making <100> The thickness at the crystal direction is the smallest. The silicon wafer is placed in the epitaxial growth base 20 of the embodiment of the present application. <110> The crystal directions are respectively arranged radially opposite to the plurality of grooves 221 to reduce the epitaxial growth of the silicon wafer. <110> crystal orientation, thereby reducing <110> The growth rate of the crystal direction increases the silicon wafer <110> Crystal orientation and <100> The consistency of the crystal growth rate can improve the edge flatness of the epitaxial layer of the silicon wafer.

[0050] It can be seen that the epitaxial growth base 20 of the embodiment of the present application can selectively suppress the growth rate of a specified crystal phase during the epitaxial growth process, so that the silicon wafer can achieve a relatively consistent growth rate in different crystal directions under different temperature conditions, thereby improving the flatness level at the edge of the silicon wafer.

[0051] In some embodiments, Figure 2 and Figure 3 As shown, the depth of the groove 221 decreases from the center position of the groove 221 in the circumferential direction toward both sides of the circumferential direction.

[0052] It can be understood that when the temperature is the same at different circumferential positions of the silicon wafer, the growth rate of the silicon wafer at different circumferential positions gradually decreases from the <110> crystal orientation to the <100> crystal orientation.

[0053] Thus, the depths of the grooves 221 at different positions can correspond to the growth rates of different circumferential positions of the silicon wafer, so that the depth of the groove 221 can gradually decrease corresponding to the positions of the silicon wafer in the circumferential direction from the <110> crystal orientation to the <100> crystal orientation, facilitating the removal of different amounts of heat from different crystal orientations of the silicon wafer, that is, the cooling effect of the groove 221 gradually weakens from the central position towards both circumferential sides in the circumferential direction, making the cooling effect between the <110> crystal orientation and the <100> crystal orientations on both sides of the silicon wafer gradually weaken in the circumferential direction, thereby facilitating the better matching of the growth rate and temperature distribution of the silicon wafer between the <110> crystal orientation and the <100> crystal orientation in the circumferential direction, which is beneficial to further improving the flatness level of the epitaxial layer of the silicon wafer.

[0054] It can be understood that from the central position of the groove 221 in the circumferential direction towards both circumferential sides, the depth of the groove 221 can decrease linearly or non-linearly with the central angle; for example, taking the position where the notch 11 (i.e., notch) of the silicon wafer is located as 0°, and taking the center of the bearing part 21 as the origin, the depth of the groove 221 at the corresponding position and the polar angle at the corresponding position can be a linear relationship or a non-linear relationship.

[0055] Furthermore, as Figure 2 shown, the outer peripheral contour of the edge part 22 is circular, and the bottom wall of the groove 221 extends along a straight line, which is convenient for simplifying the structure of the groove 221 and facilitating processing.

[0056] In some embodiments, as Figure 3 shown, the thickness t of the edge part 22 is greater than the thickness t1 of the bearing part 21, which is convenient for the edge part 22 to limit the placement position of the silicon wafer in the receiving groove 23, and at the same time, it is convenient for the edge part 22 to have sufficient structural strength and reliability even when the groove 221 is provided. At the same time, in the radial direction of the edge part 22, the maximum depth of the groove 221 is less than the radial width of the edge part 22 and greater than half of the radial width of the edge part 22. If the radial width of the edge part 22 is w and the maximum depth of the groove 221 is h, then w / 2 < h < w. At this time, the groove 221 will not extend to the bearing part 21, so as to avoid overly weakening the epitaxial growth base 20 while meeting the requirement of improving the temperature distribution, and it is convenient to take into account the connection reliability between the edge part 22 and the bearing part 21. Exemplarily, h can be 0.6*w, 0.7*w, 0.8*w or 0.9*w, etc.

[0057] Further, the groove 221 is arranged to meet the conditions: w≥36 mm, 20 mm≤h≤35 mm. Thus, while facilitating the improvement of the temperature distribution, it is beneficial to carry and epitaxially grow silicon wafers of different sizes. Exemplarily, w can be 36 mm, 40 mm, 50 mm, or 60 mm, etc., and h can be 20 mm, 25 mm, 30 mm, or 35 mm, etc.

[0058] Optionally, for the epitaxial growth pedestal 20 with a diameter of 373.32 mm, the portion between a diameter of 301.12 mm and a diameter of 373.32 mm can be the edge portion 22.

[0059] In some embodiments, as Figure 3 shown, the thickness of the edge portion 22 is t, and the minimum distance between the groove 221 and the end faces at both ends of the bearing portion 21 is x, 4.5 mm≤t≤8 mm, 0.2 mm≤x≤2 mm. Exemplarily, t is 4.5 mm, 5 mm, 5.8 mm, 6 mm, 6.4 mm, 7 mm, 7.5 mm or 8 mm, etc.; x is 0.2 mm, 0.5 mm, 1 mm, 1.4 mm, or 2 mm, etc. Thus, the edge portion 22 has a suitable thickness to facilitate the setting of the groove 221, and at the same time, the position of the groove 221 can be well matched with the thickness of the edge portion 22, and the edge portion 22 is not easily weakened excessively due to the setting of the groove 221.

[0060] It can be understood that axially, the minimum distance between the groove 221 and the end faces at both ends of the bearing portion 21 can be equal or unequal, and axially, the center of the groove 221 and the center of the bearing portion 21 can be arranged flush or offset.

[0061] In the embodiments of the present application, the longitudinal cross-sectional shape of the groove 221 is not limited, and the longitudinal cross-section passes through the central axis of the bearing portion 21. For example, the longitudinal cross-sectional shape of the groove 221 is one or more of a polygon, a semi-circle, and a semi-ellipse; in Figure 3 the example, the longitudinal cross-sectional shape of the groove 221 is triangular, which is convenient for processing.

[0062] In some embodiments, as Figure 2 shown, there are four grooves 221, and the four grooves 221 are arranged at equal intervals in the circumferential direction. In the cross-section of the edge portion 22, with the central axis of the edge portion 22 as the center of the circle, the central angle corresponding to each groove 221 is α, 50°≤α≤70°. Exemplarily, α can be 50°, 55°, 60°, 66°, or 70°, etc.

[0063] Since the temperature at different circumferential positions of the silicon wafer is consistent, the growth rate of the silicon wafer at different circumferential positions varies from <110> Crystal to <100> The crystal direction gradually decreases. Therefore, in the above scheme, the center angle α corresponding to the groove 221 is set to improve the self- <110> The temperature distribution within a certain range on both sides of the crystal direction position makes the temperature distribution consistent with the crystal direction distribution, which is convenient for further improving the consistency of the growth rates of different crystal directions. It is not easy for the cooling effect to be unclear due to the setting of the center angle α corresponding to the groove 221 being too small, nor is it easy for the cooling range to be too large and affect the overall growth rate due to the setting of the center angle α corresponding to the groove 221 being too large, thereby facilitating taking into account both the local cooling effect and the overall growth rate.

[0064] According to the epitaxial growth device 100 of the second embodiment of the utility model, Figure 5 and Figure 6 As shown, it includes a cooling structure 30 and the epitaxial growth base 20 of the above embodiment, the cooling structure 30 is used to blow cooling gas toward a preset area, and the epitaxial growth base 20 can be rotatably set so that the outer peripheral wall of the edge portion 22 passes through the preset area. The outer peripheral wall portion of the edge portion 22 passing through the preset area can be cooled by the cooling gas, and due to the setting of the groove 221, the cooling effect at the position where the groove 221 is set is better than the cooling effect at the position where the groove 221 is not set, thereby improving the consistency of the growth rates in different crystal directions.

[0065] The epitaxial growth device 100 of the embodiment of the present application adopts the epitaxial growth base 20 of the above embodiment. During the rotation of the epitaxial growth base 20, the cooling gas can exchange heat with the groove wall of the groove 221 to take away more heat at the position of the groove 221, so as to reduce the temperature of the edge portion 22 at the groove 221, and then reduce the temperature of the substrate 10 in the receiving groove 23 at the edge of the periphery toward the groove 221, so that the temperature of the silicon wafer in different crystal directions is different, so as to reduce the influence of the growth rate of different crystal directions on the flatness, so as to achieve the purpose of improving the flatness level of the epitaxial layer. It can be seen that the epitaxial growth device 100 of the embodiment of the present application is convenient for selectively suppressing the growth rate of a specified crystal direction, improving the consistency of the growth rate of different crystal directions, thereby improving the flatness level of the epitaxial layer of the substrate, and for the processing of back-end wafer devices, it can improve the product yield.

[0066] It can be understood that the epitaxial growth device may include a shell, which defines an epitaxial cavity, and the epitaxial growth base 20 is rotatably disposed in the epitaxial cavity. The cooling structure 30 may be disposed in the shell and used to blow cooling gas toward a preset area.

[0067] In some embodiments, Figure 5 and Figure 6As shown, the blowing angle of the cooling structure 30 is fixedly set or adjustable, and the blowing angle is between a first angle and a second angle. At the first angle (such as Figure 5 shown), the cooling structure 30 blows air along a direction tangent to the outer peripheral wall of the edge portion 22. At the second angle (such as Figure 6 shown), the cooling structure 30 blows air towards the cylindrical surface where the deepest position of the plurality of grooves 221 is located; and / or, the blowing flow rate of the cooling structure 30 is adjustable, and the blowing flow rate is within the range of 2 - 15 slm (volume flow unit, standard liters per minute).

[0068] It can be understood that when the blowing angle of the cooling structure 30 is fixedly set, the blowing angle can be fixed at any angular position between the first angle and the second angle (including the first angle and the second angle), maintaining a constant blowing direction, which is convenient for reducing the requirements for the cooling structure 30 and facilitating implementation; when the blowing angle of the cooling structure 30 is adjustable, the blowing angle can be adjusted between the first angle and the second angle (including the first angle and the second angle). For example, the blowing angle can be adjusted in matching with the rotation of the epitaxial growth base 20. When the position of the groove 221 rotates to a preset area, the cooling structure 30 can be adjusted to blow at the second angle, and when the position without the groove 221 rotates to the preset area, the cooling structure 30 can be adjusted to blow at the first angle, so as to realize the adjustment of the cooling capacity, and different cooling effects can be achieved at different positions on the outer peripheral wall of the edge portion 22. The first cooling effect is achieved at the position of the groove 221, and the second cooling effect is achieved at the position without the groove 221. The first cooling effect is better than the second cooling effect, which is beneficial to improving the rational utilization of the cooling gas.

[0069] In addition, when the blowing flow rate of the cooling structure 30 is adjustable, the cooling capacity of the cooling structure 30 can also be adjusted, which is convenient for achieving different cooling effects at different positions on the outer peripheral wall of the edge portion 22; for example, when the position of the groove 221 rotates to a preset area, the cooling structure 30 can be adjusted to blow at the first flow rate, and when the position without the groove 221 rotates to a preset area, the cooling structure 30 can be adjusted to blow at the second flow rate. The first flow rate can be greater than the second flow rate, which can also improve the rational utilization of the cooling gas.

[0070] Of course, in other embodiments of the present application, the blowing flow rate of the cooling structure 30 can also be fixed and non - adjustable.

[0071] In some embodiments, such as Figure 5 and Figure 6 shown, from the central position of the groove 221 in the circumferential direction towards both circumferential sides, the depth of the groove 221 decreases, the blowing angle of the cooling structure 30 is adjustable, and the epitaxial growth device 100 has a first mode and a second mode.

[0072] In the first mode, as the epitaxial growth pedestal 20 rotates, the depth of the groove 221 of the portion of the edge portion 22 within the preset area increases, and the blowing angle deflects towards the second angle; in the second mode, as the epitaxial growth pedestal 20 rotates, the depth of the groove 221 of the portion of the edge portion 22 within the preset area decreases, and the blowing angle deflects towards the first angle.

[0073] For example, taking the silicon wafer with <100> crystal orientation and <110> crystal orientation described above as an example, when the silicon wafer is placed in the receiving groove 23, the <110> crystal orientation position is radially aligned with the groove 221. Then, in the first mode, since the depth of the groove 221 within the preset area increases, along with the rotation direction of the epitaxial growth pedestal 20, the <110> crystal orientation position corresponding to the groove 221 is about to rotate into the preset area. The <110> crystal orientation position requires a higher cooling efficiency, so the cooling effect required by the silicon wafer also increases as the epitaxial growth pedestal 20 rotates. And deflecting the blowing angle towards the second angle can increase the cooling effect of the cooling structure 30 on the epitaxial growth pedestal 20, making the changing trends of the cooling effect that the cooling structure 30 can achieve and the cooling effect required by the epitaxial growth pedestal 20 consistent; similarly, in the second mode, since the depth of the groove 221 within the preset area decreases, along with the rotation direction of the epitaxial growth pedestal 20, the <110> crystal orientation position corresponding to the groove 221 is about to leave the preset area or has already left the preset area, and the <100> crystal orientation position is about to rotate into the preset area. The <100> crystal orientation position requires a lower cooling efficiency or basically no cooling, so the cooling effect required by the silicon wafer also decreases as the epitaxial growth pedestal 20 rotates. And deflecting the blowing angle towards the first angle can decrease the cooling effect of the cooling structure 30 on the epitaxial growth pedestal 20, making the changing trends of the cooling effect that the cooling structure 30 can achieve and the cooling effect required by the epitaxial growth pedestal 20 consistent.

[0074] Thus, in both the first mode and the second mode, the changing trends of the cooling effect that the cooling structure 30 can achieve and the cooling effect required by the epitaxial growth pedestal 20 can be made consistent, facilitating the realization of corresponding and matching cooling effects for different crystal orientations, which is beneficial to further reducing the difference in the growth rates of the silicon wafer in different crystal orientations and further improving the flatness level at the edge of the silicon wafer.

[0075] Other components and operations of the epitaxial growth apparatus 100 according to the embodiments of the present invention are known to those of ordinary skill in the art and will not be described in detail here.

[0076] Next, refer to Figures 1 - 6 A specific embodiment is used to describe in detail the epitaxial growth apparatus 100 according to the embodiments of the present invention. It should be understood that the following description is only an exemplary illustration and not a specific limitation of the present invention.

[0077] like Figures 1 - 6 As shown, the epitaxial growth device 100 includes an epitaxial growth base 20 and a cooling structure 30. The cooling structure 30 is used to blow cooling gas toward a preset area. The epitaxial growth base 20 can be rotatably arranged so that the outer peripheral wall of the epitaxial growth base 20 passes through the preset area, so that the cooling gas blown out by the cooling structure 30 can exchange heat with the outer peripheral wall of the epitaxial growth base 20 to take away the heat of the epitaxial growth base 20 and the silicon wafer thereon.

[0078] The epitaxial growth base 20 is a graphite part and includes a bearing portion 21 and an edge portion 22. The edge portion 22 is formed into an annular structure and is arranged around the outer peripheral side of the bearing portion 21, and defines a receiving groove 23 with the bearing portion 21 on one side of the bearing portion 21. Four grooves 221 are formed on the outer peripheral wall of the edge portion 22 and are equally spaced along the circumference of the edge portion 22. In the axial direction of the edge portion 22, the grooves 221 are spaced from the end surfaces of the edge portion 22 at both ends. In the cross section of the edge portion 22, with the central axis of the edge portion 22 as the center of the circle, the central angle corresponding to each groove 221 is α, 50°≤α≤70°, and the cross section of the edge portion 22 is perpendicular to the central axis of the edge portion 22. Among them, the outer peripheral contour of the edge portion 22 is circular, the bottom wall of the groove 221 extends along a straight line, and the longitudinal cross-sectional shape of the groove 221 is a triangle, and the vertex of the triangle is flush with the center of the edge portion 22 in the axial direction (of course, the vertex of the triangle can also be set away from the center of the edge portion 22 in the axial direction); in the radial direction of the edge portion 22, the maximum depth h of the groove 221 is less than the radial width w of the edge portion 22 and greater than half of the radial width w of the edge portion 22, w≥36mm, 20mm≤h≤35mm; the thickness of the edge portion 22 is t, and the minimum spacing between the end faces of the groove 221 and the bearing portion 21 is x, 4.5mm≤t≤8mm, 0.2mm≤x≤2mm.

[0079] Accordingly, the silicon wafer has a radially extending <100> Crystal orientation and <110> Crystal direction, four <100> Crystal direction and four <110> The crystal directions alternate along the circumference, four <100> The crystal directions are equally spaced along the circumference, and the four <110> The crystal directions are also equally spaced along the circumference, and adjacent <100> Crystal orientation and <110> The circumferential spacing between the crystal directions is 45°; the silicon wafer is placed in the receiving groove 23, four <110> The crystal direction is arranged radially opposite to the four grooves 221 one by one, for example Figure 1 The silicon wafer shown can be placed directly on the Figure 2In the accommodating groove 23 shown, with the position corresponding to the notch 11 being 0°, the four <110> crystal orientations are respectively located at 0°, 90°, 180°, and 270°, and the four <100> crystal orientations are respectively located at 45°, 135°, 225°, and 315°. Then the four <110> crystal orientations respectively correspond to the positions of the maximum depths of the four grooves 221. When the <110> crystal orientation rotates to the preset area, the contact area between the cooling gas and the edge portion 22 is the largest. Compared with other positions, the cooling structure 30 can take away the most heat.

[0080] The cooling structure 30 is configured as follows: 1. The blowing angle of the cooling structure 30 is fixedly set and the blowing angle is between the first angle and the second angle; or 2. The blowing angle of the cooling structure 30 is adjustable and the blowing angle is between the first angle and the second angle. The epitaxial growth device 100 has a first mode and a second mode. In the first mode, the depth of the groove 221 of the part of the edge portion 22 located within the preset area increases as the epitaxial growth base rotates, and the blowing angle deflects towards the second angle. In the second mode, the depth of the groove 221 of the part of the edge portion 22 located within the preset area decreases as the epitaxial growth base 20 rotates, and the blowing angle deflects towards the first angle. Among them, at the first angle, the cooling structure 30 blows air along the direction tangent to the outer peripheral wall of the edge portion 22, and the blowing angle is 0°; at the second angle, the cooling structure 30 blows air towards the cylindrical surface where the deepest positions of the multiple grooves 221 are located, and the blowing angle is 5° (of course, the blowing angle at this time can be specifically set according to the relative position between the cooling structure 30 and the epitaxial growth base 20).

[0081] Figure 8 It is a schematic diagram of the thickness of the silicon wafer grown on the epitaxial growth base without grooves in the prior art; Figure 9 It is a schematic diagram of the thickness of the silicon wafer grown on the epitaxial growth base 20 provided with the grooves 221 in the embodiment of the present application. It can be clearly seen that the flatness level of the silicon wafer in the improved solution of the embodiment of the present application is improved. Further, taking the epitaxial growth base 20 with a diameter of 373.32 mm as an object, the part between a diameter of 301.12 mm and a diameter of 373.32 mm is the edge portion 22, and in cooperation with the cooling structure 30, multiple experimental schemes are designed. Before multiple experimental schemes, a suitable epitaxial substrate is selected and the previous values are basically the same. The epitaxial growth device 100 provided in the embodiment of the present application is used for epitaxial growth, and the flatness of the epitaxial wafer is measured on the same machine table to obtain the results shown in Table 1.

[0082] Table 1

[0083]

[0084] In Table 1, in the solution where the blowing angle is "active", the blowing angle of the cooling structure 30 is adjustable, and the blowing angle is between the first angle and the second angle, so that the epitaxial growth device 100 has a first mode and a second mode; more specifically, when the four <110> crystal orientations, namely the 0°, 90°, 180°, and 270° positions, rotate to the preset area, the blowing angle is 5° for all of them, and when the four <100> crystal orientations, namely the 45°, 135°, 225°, and 315° positions, rotate to the preset area, the blowing angle is 0°, and the blowing angle of the cooling structure 30 swings between 0° and 5° as the epitaxial growth base 20 rotates.

[0085] It can be clearly seen from Table 1 that for Solution 2-9 of the embodiments of the present application, compared with Solution 1 of the comparative embodiment, the ESFQR MAX level of the silicon wafers has been improved, and especially Solution 10 can significantly improve the process capability. It can be seen that the epitaxial growth device 100 of the embodiments of the present application can optimize the temperature distribution and gas flow distribution in the edge region of the silicon wafer during epitaxial growth, reduce the influence of temperature and gas flow fields on the flatness of the edge of the silicon wafer, and improve the process capability.

[0086] In addition, it should be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable way without contradiction. To avoid unnecessary repetition, the present application does not separately describe various possible combination methods. In addition, any combination can be made between various different embodiments of the present application, as long as it does not violate the idea of the present application, it should also be regarded as the content disclosed by the present application.

[0087] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "width", "thickness", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present utility model. In addition, the features defined as "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present utility model, unless otherwise specified, the meaning of "plurality" is two or more.

[0088] In the description of the present utility model, it should be noted that, unless otherwise clearly specified and defined, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.

[0089] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present utility model. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0090] Although the embodiments of the present utility model have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and purposes of the present utility model, and the scope of the present utility model is defined by the claims and their equivalents.

Claims

1. An epitaxial growth base, characterized in that: include: load-bearing part; The edge portion is formed into an annular structure and is arranged around the outer peripheral side of the bearing portion, and defines a receiving groove with the bearing portion on one side of the bearing portion, and the receiving groove is used to place the substrate. A plurality of grooves arranged at intervals along the circumference of the edge portion are formed on the outer peripheral wall of the edge portion, and in the axial direction of the edge portion, the grooves are respectively spaced apart from the end faces of the edge portion at both ends.

2. The epitaxial growth base according to claim 1, characterized in that: The depth of the groove decreases from the center position of the groove in the circumferential direction toward both sides in the circumferential direction.

3. The epitaxial growth base according to claim 2, characterized in that: The outer peripheral contour of the edge portion is circular, and the bottom wall of the groove extends along a straight line.

4. The epitaxial growth base according to claim 1, characterized in that: The thickness of the edge portion is greater than the thickness of the bearing portion. In the radial direction of the edge portion, the maximum depth of the groove is less than the radial width of the edge portion and greater than half of the radial width of the edge portion.

5. The epitaxial growth base according to claim 4, characterized in that: The setting of the groove meets the following conditions: the radial width of the edge portion is w, the maximum depth of the groove is h, w≥36mm, 20mm≤h≤35mm.

6. The epitaxial growth base according to claim 1, characterized in that: The thickness of the edge portion is t, the minimum distance between the groove and the end surfaces of both ends of the bearing portion is x, 4.5mm≤t≤8mm, 0.2mm≤x≤2mm.

7. The epitaxial growth base according to any one of claims 1 to 6, characterized in that: There are four grooves which are arranged at equal intervals along the circumferential direction. On the cross section of the edge portion, with the central axis of the edge portion as the center of the circle, the central angle corresponding to each groove is α, and 50°≤α≤70°.

8. An epitaxial growth device, characterized in that: include: A cooling structure and an epitaxial growth base according to any one of claims 1 to 7, wherein the cooling structure is used to blow cooling gas toward a preset area, and the epitaxial growth base can be rotatably arranged so that the outer peripheral wall of the edge portion passes through the preset area.

9. The epitaxial growth device according to claim 8, characterized in that: The cooling structure is configured as follows: The blowing angle of the cooling structure is fixed or adjustable, and the blowing angle is between a first angle and a second angle, at the first angle, the cooling structure blows airflow in a direction tangential to the outer peripheral wall of the edge portion, and at the second angle, the cooling structure blows airflow toward a cylindrical surface where the deepest positions of the plurality of grooves are located; and / or, The blowing flow rate of the cooling structure is adjustable, and the blowing flow rate is within the range of 2 to 15 slm.

10. The epitaxial growth device according to claim 9, characterized in that: The depth of the groove decreases from the center position of the groove in the circumferential direction toward the two sides in the circumferential direction, the blowing angle of the cooling structure is adjustable, and the epitaxial growth device has a first mode and a second mode. In the first mode, the depth of the groove of the edge portion located in the preset area increases as the epitaxial growth base rotates, and the blowing angle deflects toward the second angle; In the second mode, the depth of the groove of the edge portion located in the preset area decreases as the epitaxial growth base rotates, and the blowing angle deflects toward the first angle.

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