TWI879315B - Device, method and epitaxial device for calibrating the position of a silicon wafer relative to a base - Google Patents

Abstract

The present invention discloses an apparatus, method and epitaxial equipment for calibrating the position of a silicon wafer relative to a base, wherein 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 perpendicular to the first diameter are measured, and a reference distance for moving the silicon wafer in the direction of the first diameter is obtained based on the first distance and the second distance and the first reference distance and the second reference distance. A first moving direction and a first moving distance aligned with a reference position in the direction of a second diameter are obtained based on a third spacing and a fourth spacing and the third reference spacing and a fourth reference spacing so as to enable the silicon wafer to move in the direction of the second diameter so as to be aligned with the reference position in the direction of the first diameter, and the silicon wafer is moved in accordance with the first moving direction and the first moving distance and the second moving direction and the second moving distance.

Description

Device, method and epitaxial device for calibrating the position of a silicon wafer relative to a base

Cross-references to related applications

This invention claims priority to Chinese Patent Application No. 202310197983.1 filed in China on March 3, 2023, the entire contents of which are incorporated herein by reference.

The present invention relates to the field of semiconductor silicon wafer production, and more particularly to a device, method and epitaxial equipment for calibrating the position of a silicon wafer relative to a base.

The production of silicon wafers usually requires processes such as crystal pulling, forming, polishing, cleaning, and epitaxy (also known as epitaxy) to be used as storage chips, power devices, etc. With the rapid development of the integrated circuit industry, the requirements for epitaxial silicon wafers are becoming higher and higher, such as the thickness, flatness, resistivity and surface particle contamination of the epitaxial layer.

In the epitaxial growth equipment, the transfer blades in the front-end module transfer the silicon wafer from the loading port to the load lock unit, which is evacuated and backfilled with nitrogen. The transfer robot in the transfer unit transfers the silicon wafer in the load lock unit into the process reaction chamber for epitaxial growth. After the growth is completed, the epitaxial silicon wafer is returned along the original route.

Since the atomic density of heavily doped epitaxial wafers and lightly doped epitaxial wafers is different, the stress deformation of the edge of the silicon wafer in the reaction chamber of the epitaxial furnace due to high temperature is different. If the position of the silicon wafer on the base cannot be adjusted in time or the position of the robot transferring the silicon wafer into the process reaction chamber is incorrect, it will have an adverse effect on the thickness, flatness and resistivity of the epitaxial layer. In addition, if the outer edge of the silicon wafer contacts the base, it will cause the edge of the epitaxial silicon wafer to gather contaminated particles after epitaxial growth, affecting the yield of the epitaxial silicon wafer.

Therefore, it is important to calibrate the position of the silicon wafer relative to the base of the epitaxial equipment so that the silicon wafer is at the desired position. However, in the current silicon wafer position calibration method, it is manually calibrated by visual inspection when the equipment is stopped, which is inefficient, has poor accuracy, is time-consuming, and affects normal production.

To solve the above technical problems, the embodiments of the present invention hope to provide a device, method and epitaxial equipment for calibrating the position of a silicon wafer relative to a base, which can realize automatic calibration of the silicon wafer in a simple and convenient manner, thereby improving production efficiency and calibration accuracy.

The technical solution of the present invention is achieved in this way:

In a first aspect, an embodiment of the present invention provides a device for calibrating the position of a silicon wafer relative to a base, the device comprising:

A measuring unit, the 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;

a first acquisition unit, the first acquisition unit being used to acquire a first moving direction and a first moving distance based on the first spacing and the second spacing and a first reference spacing and a 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 at a reference position relative to the base, wherein 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 in the direction of the first diameter;

a second acquisition unit, the second acquisition unit being used to acquire a second moving direction and a second moving distance based on the third spacing and the fourth spacing and the third reference spacing and the fourth reference spacing between the periphery of the base and the periphery of the silicon wafer on the second diameter when the silicon wafer is at the reference position relative to the base, wherein 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 in the direction of the second diameter;

A driving unit, wherein the driving unit is used to move the silicon chip according to the first moving direction and the first moving distance and to move the silicon chip according to the second moving direction and the second moving distance.

In a second aspect, an embodiment of the present invention provides an epitaxial device, which includes the apparatus according to the first aspect.

In a third aspect, an embodiment of the present invention provides a method for calibrating the position of a silicon wafer relative to a base, the method comprising:

Measuring a first distance and a second distance between a periphery of the base and a 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;

Obtaining a first moving direction and a first moving distance based on the first spacing and the second spacing and a first reference spacing and a 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 at a reference position relative to the base, wherein 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 in the direction of the first diameter;

Obtaining a second moving direction and a second moving distance based on the third spacing and the fourth spacing and the third reference spacing and the fourth reference spacing between the periphery of the base and the periphery of the silicon wafer on the second diameter when the silicon wafer is at the reference position relative to the base, wherein 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 in the direction of the second diameter;

The silicon chip is moved in the first moving direction and the first moving distance and the silicon chip is moved in the second moving direction and the second moving distance.

The embodiments of the present invention provide a device, method and epitaxial equipment for calibrating the position of a silicon wafer relative to a base. The determination of the moving distance and moving direction of the silicon wafer and the realization of the movement are all completed in an automated manner, thereby improving production efficiency and calibration accuracy. In addition, the reference position of the silicon wafer is stipulated or defined in the form of four reference distances between the periphery of the base and the periphery of the silicon wafer on two mutually perpendicular diameters, thereby only needing to measure the corresponding four distances, and the moving distance and moving direction that can move the silicon wafer to the reference position can be determined by simple four arithmetic operations. In addition, the movement occurs in two directions orthogonal to each other and is not affected by the order of precedence, thereby simplifying the movement. Compared with, for example, determining a circle by three points, the use of complex trigonometric functions is avoided and the calculation process is greatly simplified, while compared with, for example, determining a circle by four or more points, the number of measurement steps is reduced and the calculation process is simplified.

The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention.

Referring to FIG. 1 , an embodiment of the present invention provides a device 10 for calibrating the position of a silicon wafer W relative to a base 20. The device 10 may include:

A measuring unit 100, the measuring unit 100 is used to measure a first distance L1 and a second distance L2 between a periphery 20E of the base 20 and a periphery WE of the silicon wafer W on a first diameter 20D1 of the base 20, and a third distance L3 and a fourth distance L4 on a second diameter 20D2 of the base 20, wherein the first diameter 20D1 and the second diameter 20D2 are perpendicular to each other;

The first acquisition unit 200 is used to acquire a first moving direction MD based on the first spacing L1 and the second spacing L2 and a first reference spacing SL1 and a 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 as shown by the dotted line in the example shown in FIG. 1 1 and a first moving distance ML1, 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. Specifically, in the example shown in FIG. 1, when the silicon wafer W moves in the direction of the second diameter 20D2, the difference between the second distance L2 and the first distance L1 is constant, so that The first moving distance ML1=(L2-L1)/2+(SL1-SL2)/2 is obtained. As for the first moving direction MD1, it must be in the direction of the first diameter 20D1. It only needs to be determined whether it is to the left or to the right. It can be intuitively seen from FIG. 1 that it is from left to right. In addition, although it is not shown in the figure, it can be understood by referring to FIG. 1. It is assumed that the silicon wafer W is located at the center of the base 20 in the direction of the first diameter 20D1. Between the reference position, the first moving distance ML1=(SL1-SL2)/2-(L1-L2)/2, and the first moving direction is from left to right. In addition, although not shown in the figure, it can be understood with reference to FIG. 1 that, assuming that the silicon wafer W is located on the right side 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;

The second acquisition unit 300 is used to acquire a second moving direction MD2 and a second moving distance ML2 based on the third distance L3 and the fourth distance L4 and a third reference distance SL3 and a fourth reference distance 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 the silicon wafer W in the direction of the second diameter 20D2. Specifically, in the example shown in FIG. 1 , similarly, since the difference between the third distance L3 and the fourth distance L4 is constant when the silicon wafer W moves in the direction of the first diameter 20D1, it can be concluded that the second moving direction MD2 and the second moving distance ML2 are aligned with the reference position in the direction of the first diameter 20D1. The moving distance ML2 = (L3-L4)/2 + (SL4-SL3)/2, and for the second moving direction MD2, it must be in the direction of the second diameter 20D2. It only needs to be determined whether it is upward or downward. It can be intuitively seen from FIG1 that it is from bottom to top. In addition, although it is not shown in the figure, it can be understood by referring to FIG1. It is assumed that the silicon wafer W is located between the center of the base 20 and the reference in the direction of the second diameter 20D2. The second moving distance ML2 = (SL4-SL3)/2-(L4-L3)/2, and the second moving direction is from bottom to top. In addition, although not shown in the figure, it can be understood with reference to FIG. 1 that, assuming that the silicon wafer W is located on the upper side of the reference position in the direction of the second diameter 20D2, the second moving distance ML2 = (SL4-SL3)/2+(L4-L3)/2, and the second moving direction is from top to bottom;

The driving unit 400 is used to move the silicon wafer W according to the first moving direction MD1 and the first moving distance ML1 and to move the silicon wafer W according to the second moving direction MD2 and the second moving distance ML2, thereby calibrating the silicon wafer W to the above-mentioned reference position.

In the present invention, the determination of the moving distance and moving direction of the silicon wafer W and the realization of the movement are all completed in an automated manner, thereby improving production efficiency and calibration accuracy. In addition, the reference position of the silicon wafer W is stipulated or defined in the form of four reference distances between the periphery 20E of the base 20 and the periphery WE of the silicon wafer W on two perpendicular diameters. Therefore, only the corresponding four distances need to be measured, and the moving distance and moving direction that can move the silicon wafer W to the reference position can be determined by simple four arithmetic operations. In addition, the movement occurs in two directions that are orthogonal to each other and is not affected by the order of precedence, thereby simplifying the movement. Compared with, for example, determining a circle by three points, the use of complex trigonometric functions is avoided and the calculation process is greatly simplified, while compared with, for example, determining a circle by four or more points, the number of measurement steps is reduced and the calculation process is simplified.

Typically, in a process such as epitaxial processing of a silicon wafer W, the silicon wafer W needs to be centered relative to the base 20, that is, in the reference position of the silicon wafer W, the silicon wafer W and the base 20 are concentric without any eccentricity. In this case, in an optional embodiment of the present invention, see FIG. 2 , in the reference position, that is, when the silicon wafer W is in the position indicated by the dotted line, the silicon wafer W and the base 20 can be concentric with each other, and,

The first acquisition unit 200 may include:

a first distance determination module 210, wherein the first distance determination module 210 is used to calculate a first difference between the first distance L1 and the second distance L2 and use half of the first difference as the first moving distance ML1;

The first direction determining module 220 is used to compare the first distance L1 and the second distance L2 and use the direction from the smaller distance of the first distance L1 and the second distance L2 to the larger distance of the first distance L1 and the second distance L2 as the first moving direction MD1. In FIG. 2 , the direction is from the smaller first distance L1 to the larger second distance L2, that is, from left to right.

The second acquisition unit 300 may include:

a second distance determination module 310, the second distance determination module 310 being used to calculate a second difference between the third distance L3 and the fourth distance L4 and to use half of the second difference as the second moving distance ML2;

The second direction determining module 320 is used to compare the third distance L3 and the fourth distance L4 and take the direction from the smaller distance between the third distance L3 and the fourth distance L4 to the larger distance between the third distance L3 and the fourth distance L4 as the second moving direction MD2.

Regarding the offset of the silicon wafer W relative to the base 20, sometimes, although the offset exists, if the offset is very small, it is not necessary to calibrate the silicon wafer W. In this regard, in an optional embodiment of the present invention, referring to FIG. 3 , the device 10 may further include:

The third acquisition unit 500 is used to acquire the actual offset of the silicon wafer W by using the first spacing L1, the second spacing L2, the third spacing L3 and the fourth spacing L4 and the first reference spacing SL1, the second reference spacing SL2, the third reference spacing SL3 and the fourth reference spacing SL4, so as to compare the actual offset with the allowable offset. In this way, when the actual offset is less than the allowable offset, the silicon wafer W does not need to be calibrated. More specifically, as shown in FIG. 3 , assuming that the silicon wafer W is offset to the right in the direction of the first diameter 20D1 relative to the base 20, in this case, the actual offset of the silicon wafer W can be obtained as (SL1-L1) or (L2-SL2) by using the first spacing L1, the first reference spacing SL1 or the second spacing L2, the second reference spacing SL2, and if the actual offset is less than the allowable offset, the position of the silicon wafer W does not need to be calibrated. In addition, although it is not shown in the figure, it can be understood that assuming that the silicon wafer W is offset to the right in the direction of the second diameter 20D2 relative to the base 20, in this case, the third spacing L3, the third reference spacing SL3 or the fourth spacing L4 can be used to obtain the actual offset of the silicon wafer W. , and the fourth reference distance SL4 can obtain the actual offset of the silicon wafer W as the difference between the third distance L3 and the third reference distance SL3 or the difference between the fourth distance L4 and the fourth reference distance SL4. In addition, although it is not shown in the figure, it can be understood that, assuming that the silicon wafer W has not only offset in the direction of the first diameter 20D1 but also offset in the direction of the second diameter 20D2 relative to the base 20, as shown in FIG. 1, in this case, the first distance L1, the second distance L2, the third distance L3 and the fourth distance L4 and the first reference distance SL1, the second reference distance SL2, the third reference distance SL3 and the fourth reference distance SL4 can be obtained as:

.

In addition, the allowable offset here means that when the silicon wafer W has this offset relative to the reference position, the aforementioned problems caused, such as the adverse effects on the thickness, flatness, and resistivity of the epitaxial layer, are within an acceptable range, and the allowable offset here can be determined based on a large amount of corresponding data such as the offset and product quality obtained in the actual production process.

Since, for example, the silicon wafer epitaxial device may produce changes such as displacement of components during long-term use, which may have adverse effects on the quality of the epitaxial layer of the silicon wafer W, it is necessary to adjust the reference position of the silicon wafer W relative to the base 20 to avoid the adverse effects caused by these changes. In this regard, in an optional embodiment of the present invention, referring to FIG4 , the device 10 may be applied to an epitaxial device for growing an epitaxial layer on the silicon wafer W to obtain an epitaxial silicon wafer, and the device 10 may further include an updating unit 600, which is used to update the reference position after obtaining 40 to 60 epitaxial silicon wafers, for example, from the solid line position shown in FIG4 to the dotted line position. Thus, the adverse effect caused by the reference position of the epitaxial equipment being no longer suitable for epitaxial processing due to long-term use can be avoided.

In an optional embodiment of the present invention, referring to Fig. 5, the measuring unit 100 may include four distance meters 110, and the four distance meters 110 are arranged to be opposite to 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 mentioned above can be determined in a more direct and accurate manner.

The embodiment of the present invention further provides an epitaxial device not shown in the drawings, which may include the apparatus 10 according to the embodiments of the present invention.

6 and in combination with FIG. 1 , the present invention also provides a method for calibrating the position of a silicon wafer W relative to a base 20, the method may include:

Step S601: measuring a first distance L1 and a second distance L2 between the periphery 20E of the base 20 and the periphery WE of the silicon wafer W on a first diameter 20D1 of the base 20, and a third distance L3 and a fourth distance L4 on a second diameter 20D2 of the base 20, wherein the first diameter 20D1 and the second diameter 20D2 are perpendicular to each other;

Step S602: Obtaining a first moving direction MD1 and a first moving distance ML1 based on the first distance L1 and the second distance L2 and a first reference distance SL1 and a second reference distance 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 at a reference position relative to the base 20, wherein 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;

Step S603: Obtaining a second moving direction MD2 and a second moving distance ML2 based on the third distance L3 and the fourth distance L4 and a third reference distance SL3 and a fourth reference distance 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 at the reference position relative to the base 20, wherein 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;

Step S604: Move the silicon wafer W according to the first moving direction MD1 and the first moving distance ML1 and move the silicon wafer W according to the second moving direction MD2 and the second moving distance ML2.

Optionally, in conjunction with FIG. 2 , in the reference position, the silicon wafer W and the base 20 may be concentric with each other, and,

The step of obtaining the first moving direction MD1 and the first moving distance ML1 comprises:

Calculating a first difference between the first distance L1 and the second distance L2 and taking half of the first difference as the first moving distance ML1;

The first distance L1 and the second distance L2 are compared and the direction from the smaller distance between the first distance L1 and the second distance L2 to the larger distance between the first distance L1 and the second distance L2 is taken as the first moving direction MD1,

The step of obtaining the second moving direction MD2 and the second moving distance ML2 comprises:

Calculating a second difference between the third distance L3 and the fourth distance L4 and taking half of the second difference as the second moving distance ML2;

The third distance L3 and the fourth distance L4 are compared, and a direction from a position where the smaller distance between the third distance L3 and the fourth distance L4 is located toward a position where the larger distance between the third distance L3 and the fourth distance L4 is located is taken as the second moving direction MD2.

Optionally, in conjunction with FIG. 3 , the method may further include:

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 and the first reference spacing SL1, the second reference spacing SL2, the third reference spacing SL3 and the fourth reference spacing SL4, such as the actual offset (SL1-L1) or (L2-SL2) relative to the reference position shown by the dotted line in FIG. 3, for comparison with the allowable offset.

Optionally, in combination with Figure 4, the method can be applied to an epitaxial process of growing an epitaxial layer on the silicon wafer W to obtain an epitaxial silicon wafer, and the method can also include updating the reference position after every 40 to 60 epitaxial silicon wafers are obtained, for example, updating from the solid line position shown in Figure 4 to the dotted line position.

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

The above is only a specific implementation of the present invention, but the protection scope of the present invention is not limited thereto. Any technical personnel familiar with the technical field to which the present invention belongs can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the patent application.

10: device 100: measuring unit 110: rangefinder 20: base 20E: periphery 20D1: first diameter 20D2: second diameter 200: first acquisition unit 210: first distance determination module 220: first direction determination module 300: second acquisition unit 310: second distance determination module 320: second direction determination module 400: driving unit 500: third acquisition unit 600: updating unit L1: first distance L2: second distance L3: third distance L4: fourth distance MD1: first moving direction MD2: second moving direction ML1: first moving distance ML2: Second moving distance SL1: First reference distance SL2: Second reference distance SL3: Third reference distance SL4: Fourth reference distance W: Silicon wafer WE: Periphery

FIG1 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;

FIG2 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;

FIG3 is a schematic diagram of a third acquisition unit of the apparatus for calibrating the position of a silicon wafer relative to a base according to an embodiment of the present invention;

FIG4 is a schematic diagram of an updating unit of an apparatus for calibrating the position of a silicon wafer relative to a base according to an embodiment of the present invention;

FIG5 is a schematic diagram of four rangefinders of 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;

FIG6 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.

10: Device

100: Measurement unit

20: Base

20E: Periphery

20D1: First diameter

20D2: Second diameter

200: First acquisition unit

300: Second acquisition unit

400: Drive unit

L1: First spacing

L2: Second distance

L3: The third distance

L4: The fourth distance

MD1: First moving direction

MD2: Second moving direction

ML1: First moving distance

ML2: Second moving distance

SL1: First reference distance

SL2: Second standard spacing

SL3: The third standard spacing

SL4: Fourth standard spacing

W: Silicon wafer

WE: Zhouyuan

Claims (10)

A device for calibrating the position of a silicon wafer relative to a base, the device comprising: a measuring unit, the measuring unit being 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; a first acquisition unit, the first acquisition unit being used to acquire a first moving direction and a first moving distance based on the first distance and the second distance and a first reference distance and a second reference distance 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 being used to enable the silicon wafer to move in the first diameter by moving in the first diameter. The silicon wafer moves in the direction of the second diameter and aligns with the reference position in the direction of the second diameter; a second acquisition unit, 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 reference spacing and the fourth reference spacing between the periphery of the base and the periphery of the silicon wafer on the second diameter 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 make the silicon wafer align with the reference position in the direction of the first diameter by moving in the direction of the second diameter; a driving unit, the driving unit is used to make the silicon wafer move in the first moving direction and the first moving distance and make the silicon wafer move in the second moving direction and the second moving distance. The device as claimed in claim 1, wherein, in the reference position, the silicon chip and the base are concentric with each other, and the first acquisition unit includes: a first distance determination module, the first distance determination module is used to calculate the first difference between the first spacing and the second spacing and use half of the first difference as the first moving distance; a first direction determination module, the first direction determination module is used to compare the first spacing and the second spacing and move the smaller spacing of the first spacing and the second spacing toward the larger spacing of the first spacing and the second spacing. The second acquisition unit includes: a second distance determination module, the second distance determination module is used to calculate the second difference between the third distance and the fourth distance and use half of the second difference as the second moving distance; a second direction determination module, the second direction determination module is used to compare the third distance and the fourth distance and use the direction of the smaller distance between the third distance and the fourth distance toward the larger distance between the third distance and the fourth distance as the second moving direction. The device as claimed in claim 1 or 2, wherein the device further comprises: a third acquisition unit, the third acquisition unit being used to acquire the actual offset of the silicon wafer using the first spacing, the second spacing, the third spacing and the fourth spacing and the first reference spacing, the second reference spacing, the third reference spacing and the fourth reference spacing for comparison with the allowable offset. The device as claimed in claim 1 or 2, wherein the device is applied to an epitaxial device for growing an epitaxial layer on the silicon wafer to obtain an epitaxial silicon wafer, and the device further comprises an updating unit, which is used to update the reference position after every 40 to 60 sheets of the epitaxial silicon wafer are obtained. The device as claimed in claim 1 or 2, wherein the measuring unit comprises four rangefinders, and the four rangefinders are arranged to be opposite to each other in pairs on the first diameter and the second diameter. An epitaxial device, comprising a device as described in any one of claims 1 to 5. A method for calibrating the position of a silicon wafer relative to a base, the method comprising: measuring a first distance and a second distance between a periphery of the base and a 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; obtaining a first moving direction and a first moving distance based on the first distance and the second distance and the first reference distance and the second reference distance 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 being used to cause the silicon wafer to move in the first diameter by moving the silicon wafer in the first diameter. The second moving direction and the second moving distance are obtained based on the third spacing and the fourth spacing and the third and fourth spacings between the periphery of the base and the periphery of the silicon wafer on the second diameter when the silicon wafer is at the reference position relative to the base, and 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 in the direction of the second diameter; 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. A method as described in claim 7, wherein, in the reference position, the silicon wafer and the base are concentric with each other, and the obtaining of the first moving direction and the first moving distance comprises: calculating a first difference between the first spacing and the second spacing and taking half of the first difference as the first moving distance; comparing the first spacing and the second spacing and moving the smaller spacing of the first spacing and the second spacing toward the larger spacing of the first spacing and the second spacing; The direction of the position of the third spacing is taken as the first moving direction, and the obtaining of the second moving direction and the second moving distance includes: calculating the second difference between the third spacing and the fourth spacing and taking half of the second difference as the second moving distance; comparing the third spacing and the fourth spacing and taking the direction of the position of the smaller spacing of the third spacing and the fourth spacing toward the position of the larger spacing of the third spacing and the fourth spacing as the second moving direction. The method as claimed in claim 7 or 8, wherein the method further comprises: obtaining the actual offset of the silicon wafer using the first spacing, the second spacing, the third spacing and the fourth spacing and the first reference spacing, the second reference spacing, the third reference spacing and the fourth reference spacing to compare with the allowable offset. The method as claimed in claim 7 or 8, wherein the method is applied in an epitaxial process of growing an epitaxial layer on the silicon wafer to obtain an epitaxial silicon wafer, and the method further includes updating the reference position after every 40 to 60 sheets of the epitaxial silicon wafer are obtained.