Apparatus, method and epitaxial apparatus for calibrating the position of a silicon wafer relative to a susceptor

Abstract

Embodiments of the present application disclose a device, a method and an epitaxial apparatus for calibrating a position of a silicon wafer relative to a susceptor, wherein a first distance and a second distance between a periphery of the susceptor and a periphery of the silicon wafer on a first diameter of the susceptor and a third distance and a fourth distance on a second diameter of the susceptor perpendicular to the first diameter are measured, a first moving direction and a first moving distance for aligning the silicon wafer with a reference position in a direction of the second diameter by moving the silicon wafer in a direction of the first diameter are obtained based on the first distance and the second distance and a first reference distance and a second reference distance, a second moving direction and a second moving distance for aligning the silicon wafer with the reference position in a direction of the first diameter by moving the silicon wafer in a direction of the second diameter are obtained based on the third distance and the fourth distance and a third reference distance and a fourth reference distance, and the silicon wafer is moved according to the first moving direction and the first moving distance and the second moving direction and the second moving distance.

Description

Technical Field

[0001] This invention relates to the field of semiconductor silicon wafer manufacturing, and more particularly to an apparatus, method, and epitaxial device for calibrating the position of a silicon wafer relative to a substrate. Background Technology

[0002] The production of silicon wafers typically involves processes such as crystal pulling, shaping, polishing, cleaning, and epitaxy, in order to be used in memory chips, power devices, and other applications. With the rapid development of the integrated circuit industry, the requirements for epitaxial silicon wafers are becoming increasingly stringent, including aspects such as the thickness, flatness, resistivity, and surface particle contamination of the epitaxial layer.

[0003] In the epitaxial equipment, the transfer blades in the front-end module transport the silicon wafer from the loading port to the load-locking unit, where a vacuum is evacuated and nitrogen is backfilled. A transfer robot located in the transfer unit then transfers the silicon wafer from the load-locking unit into the process reaction chamber for epitaxial growth. After growth is complete, the resulting epitaxial silicon wafer returns along the same path.

[0004] Due to the difference in atomic density, heavily doped and lightly doped epitaxial wafers experience different degrees of stress deformation at their edges in the epitaxial furnace reaction chamber due to high temperatures. If the wafer's position on the substrate is not adjusted in time, or if the robotic arm incorrectly places the wafer into the process reaction chamber, it will adversely affect the thickness, flatness, and resistivity of the epitaxial layer. Furthermore, if the outer edge of the wafer comes into contact with the substrate, it can lead to the accumulation of contaminant particles at the edge of the epitaxial wafer after epitaxial growth, affecting the yield of the epitaxial wafer.

[0005] Therefore, calibrating the silicon wafer position relative to the epitaxial equipment base to ensure it is in the desired location is crucial. However, current silicon wafer position calibration methods rely on manual visual calibration while the equipment is shut down. This approach is inefficient, inaccurate, time-consuming, and disrupts normal production. Summary of the Invention

[0006] To address the aforementioned technical problems, embodiments of the present invention aim to provide an apparatus, method, and epitaxial device for calibrating the position of a silicon wafer relative to a substrate, which can achieve automated calibration of the silicon wafer in a simple and convenient manner, thereby improving production efficiency and calibration accuracy.

[0007] The technical solution of this invention is implemented as follows:

[0008] In a first aspect, embodiments of the present invention provide an apparatus for calibrating the position of a silicon wafer relative to a substrate, the apparatus comprising:

[0009] A measuring unit is used to measure a first distance and a second distance between the periphery of the base and the periphery of the silicon wafer on a first diameter of the base, and a third distance and a fourth distance on a second diameter of the base, wherein the first diameter and the second diameter are perpendicular to each other;

[0010] The first acquisition unit is configured to acquire a first moving direction and a first moving distance based on the first spacing and the second spacing, as well as a first reference spacing and a second reference spacing on the first diameter between the periphery of the base and the periphery of the silicon wafer when the silicon wafer is in a reference position relative to the base. The first moving direction and the first moving distance are used to align the silicon wafer with the reference position in the direction of the second diameter by moving it in the direction of the first diameter.

[0011] The second acquisition unit is used to acquire a second moving direction and a second moving distance based on the third spacing and the fourth spacing, and the third and fourth reference spacings on the second diameter between the periphery of the base and the periphery of the silicon wafer when the silicon wafer is in the reference position relative to the base. The second moving direction and the second moving distance are used to align the silicon wafer with the reference position in the direction of the first diameter by moving it in the direction of the second diameter.

[0012] A driving unit is configured to move the silicon wafer in a first moving direction and a first moving distance, and to move the silicon wafer in a second moving direction and a second moving distance.

[0013] In a second aspect, embodiments of the present invention provide an epitaxial device, the epitaxial device including the apparatus according to the first aspect.

[0014] Thirdly, embodiments of the present invention provide a method for calibrating the position of a silicon wafer relative to a substrate, the method comprising:

[0015] Measure the first and second spacings between the periphery of the base and the periphery of the silicon wafer on a first diameter of the base, and the third and fourth spacings on a second diameter of the base, wherein the first diameter and the second diameter are perpendicular to each other;

[0016] A first moving direction and a first moving distance are obtained based on the first spacing and the second spacing, as well as the first reference spacing and the second reference spacing between the periphery of the base and the periphery of the silicon wafer on the first diameter when the silicon wafer is in a reference position relative to the base. The first moving direction and the first moving distance are used to align the silicon wafer with the reference position in the direction of the second diameter by moving it in the direction of the first diameter.

[0017] Based on the third and fourth spacings, and the third and fourth reference spacings on the second diameter between the periphery of the base and the periphery of the silicon wafer when the silicon wafer is in the reference position relative to the base, a second moving direction and a second moving distance are obtained, the second moving direction and the second moving distance being used to align the silicon wafer with the reference position in the direction of the first diameter by moving it in the direction of the second diameter;

[0018] The silicon wafer is moved in the first moving direction and the first moving distance, and the silicon wafer is moved in the second moving direction and the second moving distance.

[0019] This invention provides an apparatus, method, and epitaxial device for calibrating the position of a silicon wafer relative to a base. The determination of the silicon wafer's movement distance and direction, as well as the implementation of the movement, are all automated, thereby improving production efficiency and calibration accuracy. Furthermore, the reference position of the silicon wafer is defined or specified by four reference distances along two mutually perpendicular diameters between the periphery of the base and the periphery of the silicon wafer. This requires only measuring the corresponding four distances, and the movement distance and direction to move the silicon wafer to the reference position can be determined through simple arithmetic operations. Moreover, the movement occurs in two orthogonal directions and is unaffected by the order of movement, thus simplifying the process. Compared to determining a circle using, for example, three points, this avoids the use of complex trigonometric functions and greatly simplifies the calculation process. And compared to determining a circle using, for example, four or more points, this reduces measurement steps and simplifies the calculation process. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of an apparatus for calibrating the position of a silicon wafer relative to a base according to an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of a first acquisition unit and a second acquisition unit of an apparatus for calibrating the position of a silicon wafer relative to a base according to an embodiment of the present invention;

[0022] Figure 3A schematic diagram of a third acquisition unit of an apparatus for calibrating the position of a silicon wafer relative to a base, according to an embodiment of the present invention;

[0023] Figure 4 A schematic diagram of an update unit for an apparatus for calibrating the position of a silicon wafer relative to a base, according to an embodiment of the present invention;

[0024] Figure 5 This is a schematic diagram of four rangefinders in a measuring unit of an apparatus for calibrating the position of a silicon wafer relative to a base, according to an embodiment of the present invention.

[0025] Figure 6 This is a schematic diagram of a method for calibrating the position of a silicon wafer relative to a base according to an embodiment of the present invention. Detailed Implementation

[0026] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0027] See Figure 1 This invention provides an apparatus 10 for calibrating the position of a silicon wafer W relative to a base 20, the apparatus 10 comprising:

[0028] Measurement unit 100 is used to measure the first distance L1 and the second distance L2 on the first diameter 20D1 of the base 20 and the second distance L3 and the fourth distance L4 on the second diameter 20D2 of the base 20 between the periphery 20E of the base 20 and the periphery WE of the silicon wafer W, wherein the first diameter 20D1 and the second diameter 20D2 are perpendicular to each other.

[0029] A first acquisition unit 200 is configured to acquire data based on the first spacing L1 and the second spacing L2, and when the silicon wafer W is positioned relative to the base 20 as follows: Figure 1 In the example shown by the dashed lines, at the reference position, the first reference distance SL1 and the second reference distance SL2 on the first diameter 20D1 between the periphery 20E of the base 20 and the periphery WE of the silicon wafer W obtain a first movement direction MD1 and a first movement distance ML1. The first movement direction MD1 and the first movement distance ML1 are used to align the silicon wafer W with the reference position in the direction of the second diameter 20D2 by moving in the direction of the first diameter 20D1. Specifically, in Figure 1In the example shown, since the difference between the second pitch L2 and the first pitch L1 remains constant when the silicon wafer W moves along the direction of the second diameter 20D2, the first moving distance ML1 can be derived as (L2-L1) / 2+(SL1-SL2) / 2. The first moving direction MD1 must be along the direction of the first diameter 20D1; it is only necessary to determine whether it is to the left or right. Figure 1 It can be visually seen that the direction is from left to right. Additionally, although not shown in the attached diagram, it can be referenced... Figure 1 Understandably, assuming the silicon wafer W is located between the center of the base 20 and the reference position in the direction of the first diameter 20D1, then the first moving distance ML1 = (SL1-SL2) / 2 - (L1-L2) / 2, and the first moving direction is from left to right. Additionally, although not shown in the accompanying drawings, reference... Figure 1 Understandably, assuming that the silicon wafer W is located to the right of the reference position in the direction of the first diameter 20D1, the first moving distance ML1 = (SL1-SL2) / 2 + (L1-L2) / 2, and the first moving direction is from right to left;

[0030] The second acquisition unit 300 is used to acquire a second moving direction MD2 and a second moving distance ML2 based on the third spacing L3 and the fourth spacing L4, and the third reference spacing SL3 and the fourth reference spacing SL4 between the periphery 20E of the base 20 and the periphery WE of the silicon wafer W on the second diameter 20D2 when the silicon wafer W is in the reference position relative to the base 20. The second moving direction MD2 and the second moving distance ML2 are used to align the silicon wafer W with the reference position in the direction of the first diameter 20D1 by moving in the direction of the second diameter 20D2. Specifically, in Figure 1 In the example shown, similarly, since the difference between the third spacing L3 and the fourth spacing L4 remains constant when the silicon wafer W moves along the direction of the first diameter 20D1, the second moving distance ML2 = (L3-L4) / 2 + (SL4-SL3) / 2 can be derived. The second moving direction MD2 must be along the direction of the second diameter 20D2; it is only necessary to determine whether it is upward or downward. Figure 1 It can be visually seen that it is from bottom to top. Additionally, although not shown in the attached diagram, it can be referenced... Figure 1 Understandably, assuming the silicon wafer W is located between the center of the base 20 and the reference position in the direction of the second diameter 20D2, then the second moving distance ML2 = (SL4-SL3) / 2 - (L4-L3) / 2, and the second moving direction is from bottom to top. Additionally, although not shown in the accompanying drawings, reference... Figure 1Understandably, assuming that the silicon wafer W is located above the reference position in the direction of the second diameter 20D2, then the second moving distance ML2 = (SL4-SL3) / 2 + (L4-L3) / 2, and the second moving direction is from top to bottom;

[0031] A driving unit 400 is configured to move the silicon wafer W along the first moving direction MD1 and the first moving distance ML1 and to move the silicon wafer W along the second moving direction MD2 and the second moving distance ML2, thereby calibrating the silicon wafer W to the aforementioned reference position.

[0032] In this invention, the determination of the moving distance and direction of the silicon wafer W, as well as the realization of the movement, are all completed automatically, thereby improving production efficiency and calibration accuracy. Furthermore, the reference position of the silicon wafer W is defined or specified by four reference distances on two mutually perpendicular diameters between the periphery 20E of the base 20 and the periphery WE of the silicon wafer W. This means that only the corresponding four distances need to be measured, and the moving distance and direction that allow the silicon wafer W to move to the reference position can be determined through simple arithmetic operations. Moreover, the movement occurs in two mutually orthogonal directions and is not affected by the order of movement, thus simplifying the process. Compared to determining a circle using, for example, three points, this avoids the use of complex trigonometric functions and greatly simplifies the calculation process. And compared to determining a circle using, for example, four or more points, this reduces the number of measurement steps and simplifies the calculation process.

[0033] Typically, in processes such as epitaxial growth of silicon wafer W, it is necessary to center silicon wafer W relative to the substrate 20. That is, in the reference position of silicon wafer W, silicon wafer W and substrate 20 are concentric without any eccentricity. In this case, in a preferred embodiment of the present invention, see... Figure 2 In the reference position, that is, when the silicon wafer W is in the position shown by the dashed line, the silicon wafer W and the base 20 can be concentric with each other, and,

[0034] The first acquisition unit 200 may include:

[0035] The first distance determination module 210 is used to calculate a first difference between the first spacing L1 and the second spacing L2 and take half of the first difference as the first moving distance ML1.

[0036] The first direction determination module 220 is used to compare the first spacing L1 and the second spacing L2, and take the direction from the position of the smaller spacing L1 to the position of the larger spacing L2 as the first moving direction MD1. Figure 2 In the middle, that is, the direction from the smaller first spacing L1 to the larger second spacing L2, that is, from left to right.

[0037] The second acquisition unit 300 may include:

[0038] The second distance determination module 310 is used to calculate the second difference between the third spacing L3 and the fourth spacing L4 and take half of the second difference as the second moving distance ML2.

[0039] The second direction determination module 320 is used to compare the third spacing L3 and the fourth spacing L4 and take the direction from the position of the smaller spacing of the third spacing L3 and the fourth spacing L4 toward the position of the larger spacing of the third spacing L3 and the fourth spacing L4 as the second moving direction MD2.

[0040] Regarding the offset of silicon wafer W relative to substrate 20, sometimes, even though the offset exists, if the offset is very small, it is not necessary to calibrate silicon wafer W. In this regard, in a preferred embodiment of the present invention, see... Figure 3 The device 10 may further include:

[0041] The third acquisition unit 500 is used to acquire the actual offset of the silicon wafer W using the first spacing L1, the second spacing L2, the third spacing L3, and the fourth spacing L4, as well as the first reference spacing SL1, the second reference spacing SL2, the third reference spacing SL3, and the fourth reference spacing SL4, and compare it with the allowable offset. Thus, if the actual offset is less than the allowable offset, the silicon wafer W does not need to be calibrated. More specifically, as in... Figure 3As shown in the figures, assuming the silicon wafer W is offset to the right in the direction of the first diameter 20D1 relative to the base 20, the actual offset of the silicon wafer W can be obtained as (SL1-L1) or (L2-SL2) using the first pitch L1 and the first reference pitch SL1, or using the second pitch L2 and the second reference pitch SL2. If this actual offset is less than the allowable offset, the position of the silicon wafer W does not need to be calibrated. Furthermore, although not shown in the figures, it is understood that assuming the silicon wafer W is offset in the direction of the second diameter 20D2 relative to the base 20, the actual offset of the silicon wafer W can be obtained as the difference between the third pitch L3 and the third reference pitch SL3, or the difference between the fourth pitch L4 and the fourth reference pitch SL4, using the third pitch L3 and the third reference pitch SL3, or using the fourth pitch L4 and the fourth reference pitch SL4. Additionally, although not shown in the figures, it is understood that assuming the silicon wafer W is offset not only in the direction of the first diameter 20D1 but also in the direction of the second diameter 20D2 relative to the base 20, as shown in the figures... Figure 1 As shown, in this case, the actual offset of the silicon wafer can be obtained using the first spacing L1, the second spacing L2, the third spacing L3, and the fourth spacing L4, as well as the first reference spacing SL1, the second reference spacing SL2, the third reference spacing SL3, and the fourth reference spacing SL4: Furthermore, the permissible offset here refers to the fact that when the silicon wafer W is offset relative to the reference position, the aforementioned problems, such as the adverse effects on epitaxial layer thickness, flatness, and resistivity, are within an acceptable range. Moreover, the permissible offset here can be determined based on a large amount of data obtained in the actual production process, such as the correspondence between offset and product quality.

[0042] Because, for example, during long-term use, silicon wafer epitaxial equipment may experience component displacement, which can adversely affect the quality of the epitaxial layer of silicon wafer W, it is necessary to adjust the reference position of silicon wafer W relative to the substrate 20 to avoid the adverse effects caused by these changes. In a preferred embodiment of the present invention, see... Figure 4 The apparatus 10 can be applied in an epitaxial device for growing an epitaxial layer on the silicon wafer W to obtain an epitaxial silicon wafer, and the apparatus 10 may further include an update unit 600, which is used to update the reference position after every 40 to 60 epitaxial silicon wafers are obtained, for example from Figure 4 The solid line position shown is updated to the dashed line position. This avoids the adverse effects caused by the reference position of the epitaxial device becoming unsuitable for epitaxial processing due to long-term use.

[0043] In a preferred embodiment of the present invention, see [link to previous document]. Figure 5The measuring unit 100 may include four rangefinders 110, which are arranged in pairs facing each other on the first diameter 20D1 and the second diameter 20D2. In this way, the first distance L1, the second distance L2, the third distance L3, and the fourth distance L4 can be determined in a more direct and accurate manner.

[0044] This invention also provides an epitaxial device (not shown in the accompanying drawings), which may include the apparatus 10 described in various embodiments of the invention.

[0045] See Figure 6 and combined Figure 1 The present invention also provides a method for calibrating the position of a silicon wafer W relative to a base 20, the method comprising:

[0046] S601: Measure the first distance L1 and the second distance L2 on the first diameter 20D1 of the base 20 and the third distance L3 and the fourth distance L4 on the second diameter 20D2 of the base 20 between the periphery 20E of the base 20 and the periphery WE of the silicon wafer W, wherein the first diameter 20D1 and the second diameter 20D2 are perpendicular to each other.

[0047] S602: Based on the first spacing L1 and the second spacing L2, and the first reference spacing SL1 and the second reference spacing SL2 between the periphery 20E of the base 20 and the periphery WE of the silicon wafer W on the first diameter 20D1 when the silicon wafer W is in a reference position relative to the base 20, a first moving direction MD1 and a first moving distance ML1 are obtained. The first moving direction MD1 and the first moving distance ML1 are used to align the silicon wafer W with the reference position in the direction of the second diameter 20D2 by moving in the direction of the first diameter 20D1.

[0048] S603: Based on the third spacing L3 and the fourth spacing L4, and the third reference spacing SL3 and the fourth reference spacing SL4 between the periphery 20E of the base 20 and the periphery WE of the silicon wafer W on the second diameter 20D2 when the silicon wafer W is in the reference position relative to the base 20, a second moving direction MD2 and a second moving distance ML2 are obtained. The second moving direction MD2 and the second moving distance ML2 are used to align the silicon wafer W with the reference position in the direction of the first diameter 20D1 by moving in the direction of the second diameter 20D2.

[0049] S604: Move the silicon wafer W in the first moving direction MD1 and the first moving distance ML1, and move the silicon wafer W in the second moving direction MD2 and the second moving distance ML2.

[0050] Preferably, combined with Figure 2 In the aforementioned reference position, the silicon wafer W can be concentric with the base 20, and,

[0051] The acquisition of the first moving direction MD1 and the first moving distance ML1 includes:

[0052] Calculate the first difference between the first spacing L1 and the second spacing L2, and take half of the first difference as the first moving distance ML1;

[0053] The first spacing L1 and the second spacing L2 are compared, and the direction from the smaller spacing L1 to the larger spacing L2 is taken as the first moving direction MD1.

[0054] The acquisition of the second movement direction MD2 and the second movement distance ML2 includes:

[0055] Calculate the second difference between the third spacing L3 and the fourth spacing L4, and take half of the second difference as the second moving distance ML2;

[0056] The third spacing L3 and the fourth spacing L4 are compared, and the direction from the smaller spacing of the third spacing L3 and the fourth spacing L4 toward the larger spacing of the third spacing L3 and the fourth spacing L4 is taken as the second moving direction MD2.

[0057] Preferably, combined with Figure 3 The method may further include:

[0058] The actual offset of the silicon wafer W is obtained using the first spacing L1, the second spacing L2, the third spacing L3, and the fourth spacing L4, as well as the first reference spacing SL1, the second reference spacing SL2, the third reference spacing SL3, and the fourth reference spacing SL4. Figure 3 The actual offset (SL1-L1) or (L2-SL2) relative to the reference position shown by the dashed line is shown in the figure for comparison with the allowable offset.

[0059] Preferably, combined with Figure 4The method can be applied to an epitaxial process in which an epitaxial layer is grown on the silicon wafer W to obtain an epitaxial silicon wafer, and the method may further include updating the reference position after every 40 to 60 of the epitaxial silicon wafers are obtained, for example from Figure 4 The solid line position shown is updated to the dashed line position.

[0060] It should be noted that the technical solutions described in the embodiments of the present invention can be combined arbitrarily without conflict.

[0061] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An apparatus for calibrating the position of a silicon wafer relative to a substrate, characterized in that, The apparatus is used in an epitaxial device for growing an epitaxial layer on the silicon wafer to obtain an epitaxial silicon wafer, the apparatus comprising: A measuring unit is used to measure a first distance and a second distance between the periphery of the base and the periphery of the silicon wafer on a first diameter of the base, and a third distance and a fourth distance on a second diameter of the base, wherein the first diameter and the second diameter are perpendicular to each other; The first acquisition unit is configured to acquire a first moving direction and a first moving distance based on the first spacing and the second spacing, as well as a first reference spacing and a second reference spacing on the first diameter between the periphery of the base and the periphery of the silicon wafer when the silicon wafer is in a reference position relative to the base. The first moving direction and the first moving distance are used to align the silicon wafer with the reference position in the direction of the second diameter by moving it in the direction of the first diameter. The second acquisition unit is used to acquire a second moving direction and a second moving distance based on the third spacing and the fourth spacing, and the third and fourth reference spacings on the second diameter between the periphery of the base and the periphery of the silicon wafer when the silicon wafer is in the reference position relative to the base. The second moving direction and the second moving distance are used to align the silicon wafer with the reference position in the direction of the first diameter by moving it in the direction of the second diameter. A driving unit, configured to move the silicon wafer along a first moving direction and a first moving distance, and to move the silicon wafer along a second moving direction and a second moving distance, thereby calibrating the silicon wafer to the reference position; and An update unit is provided for updating the reference position after every 40 to 60 of the epitaxial silicon wafers are obtained.

2. The apparatus according to claim 1, characterized in that, In the reference position, the silicon wafer and the base are concentric with each other, and The first acquisition unit includes: A first distance determination module is used to calculate a first difference between the first spacing and the second spacing and take half of the first difference as the first moving distance. A first direction determination module is used to compare the first spacing and the second spacing and take the direction from the position of the smaller spacing to the position of the larger spacing as the first moving direction. The second acquisition unit includes: The second distance determination module is used to calculate a second difference between the third spacing and the fourth spacing and take half of the second difference as the second moving distance. The second direction determination module is used to compare the third spacing and the fourth spacing and take the direction from the position of the smaller spacing to the position of the larger spacing as the second moving direction.

3. The apparatus according to claim 1 or 2, characterized in that, The device further includes: The third acquisition unit is used to acquire the actual offset of the silicon wafer using the first spacing, the second spacing, the third spacing and the fourth spacing, as well as the first reference spacing, the second reference spacing, the third reference spacing and the fourth reference spacing, and to compare it with the allowable offset.

4. The apparatus according to claim 1 or 2, characterized in that, The measuring unit includes four rangefinders, which are arranged in pairs facing each other on the first diameter and the second diameter.

5. An epitaxial device, characterized in that, The epitaxial device includes the apparatus according to any one of claims 1 to 4.

6. A method for calibrating the position of a silicon wafer relative to a substrate, characterized in that, The method is applied in the epitaxial process of growing an epitaxial layer on the silicon wafer to obtain an epitaxial silicon wafer, and the method includes: Measure a first and a second distance between the periphery of the base and the periphery of the silicon wafer on a first diameter of the base, and a third and a fourth distance on a second diameter of the base, wherein the first diameter and the second diameter are perpendicular to each other; A first moving direction and a first moving distance are obtained based on the first spacing and the second spacing, as well as the first reference spacing and the second reference spacing between the periphery of the base and the periphery of the silicon wafer on the first diameter when the silicon wafer is in a reference position relative to the base. The first moving direction and the first moving distance are used to align the silicon wafer with the reference position in the direction of the second diameter by moving it in the direction of the first diameter. Based on the third and fourth spacings, and the third and fourth reference spacings on the second diameter between the periphery of the base and the periphery of the silicon wafer when the silicon wafer is in the reference position relative to the base, a second moving direction and a second moving distance are obtained, the second moving direction and the second moving distance being used to align the silicon wafer with the reference position in the direction of the first diameter by moving it in the direction of the second diameter; The silicon wafer is moved along the first moving direction and the first moving distance, and then moved along the second moving direction and the second moving distance, thereby calibrating the silicon wafer to the reference position; and The reference position is updated after every 40 to 60 of the epitaxial silicon wafers are obtained.

7. The method according to claim 6, characterized in that, In the reference position, the silicon wafer and the base are concentric with each other, and The process of obtaining the first moving direction and the first moving distance includes: Calculate the first difference between the first spacing and the second spacing, and take half of the first difference as the first moving distance; The first spacing and the second spacing are compared, and the direction from the position of the smaller spacing to the position of the larger spacing is taken as the first moving direction. The process of obtaining the second moving direction and the second moving distance includes: Calculate the second difference between the third spacing and the fourth spacing, and take half of the second difference as the second moving distance; The third spacing and the fourth spacing are compared, and the direction from the smaller spacing to the larger spacing is taken as the second moving direction.

8. The method according to claim 6 or 7, characterized in that, The method further includes: The actual offset of the silicon wafer is obtained using the first spacing, the second spacing, the third spacing, and the fourth spacing, as well as the first reference spacing, the second reference spacing, the third reference spacing, and the fourth reference spacing, and compared with the allowable offset.

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