Silicon wafer thickness measuring device and thickness measuring method

Abstract

The invention relates to a silicon wafer thickness measuring device, which is used for measuring the thickness of a silicon wafer and comprises two contact probes which can be respectively contacted with two opposite surfaces of the silicon wafer and can respectively slide on the corresponding surfaces of the silicon wafer along the radial direction of the silicon wafer; the resistance sensing device is used for being electrically connected with the two contact type probes and obtaining the resistance value of the silicon wafer when the two contact type probes are in contact with the two opposite surfaces of the silicon wafer respectively; and the processing unit is used for obtaining the thickness of the silicon wafer according to the resistance value provided by the resistance sensing device. The invention further relates to a silicon wafer thickness measuring method. The two contact type probes are respectively contacted with two opposite surfaces of the silicon wafer to measure the thickness of the silicon wafer, and the two contact type probes slide on the surface of the silicon wafer along the radial direction of the silicon wafer when the thickness of the silicon wafer is measured, so that the contact area between the contact type probes and the silicon wafer is increased, the fluctuation of the measurement of the thickness of the silicon wafer is reduced, and the measurement accuracy of the thickness of the silicon wafer is improved. And the measurement precision of the thickness of the silicon wafer is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor product manufacturing, and in particular to a silicon wafer thickness measuring device and a thickness measuring method. Background Art

[0002] Figure 1 The schematic diagram of the principle of processing silicon wafers by a double disc grinder is shown below. When the double disc grinder processes silicon wafers, the silicon wafer 10 is impacted by the airflow of the left and right static pressure plates 1 in the grinding chamber and stands upright in the grinding chamber. The grinding wheels 2 connected to the left and right spindles of the equipment stand upright on both sides of the silicon wafer 10. The left and right grinding wheels 2 rotate and feed in the direction of the silicon wafer 10, thereby grinding and thinning the rotating silicon wafer 10 to a specified thickness. The rotation of the silicon wafer 10 in the grinding chamber is achieved by the motor driving the transmission device 3 to rotate and thus driving the silicon wafer 10 to rotate. When the double disc grinder grinds the silicon wafer 10, it is necessary to measure the thickness of the silicon wafer 10 while grinding the silicon wafer 10. The thickness of the silicon wafer 10 should not be affected while measuring the thickness. The accuracy of the thickness measurement is related to the quality of the silicon wafer.

[0003] The measurement track of the silicon wafer thickness measurement device currently used on the silicon wafer surface is a circle with the same center as the silicon wafer. The measurement track covers a small area of ​​the silicon wafer surface. This measurement method causes large fluctuations in the thickness of the silicon wafer processed by the double-disc grinder and cannot be well connected to the back-end process. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a silicon wafer thickness measurement device and a thickness measurement method to solve the problem of large fluctuation in silicon wafer thickness measurement.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted in the embodiment of the present invention is: a silicon wafer thickness measuring device, used to measure the thickness of a silicon wafer, comprising:

[0006] Two contact probes, capable of respectively contacting two opposite surfaces of the silicon wafer and respectively sliding on corresponding surfaces of the silicon wafer in a radial direction of the silicon wafer;

[0007] A resistance sensing device, used to be electrically connected to the two contact probes and to obtain the resistance value of the silicon wafer when the two contact probes are in contact with two opposite surfaces of the silicon wafer respectively;

[0008] The processing unit is used to obtain the thickness of the silicon wafer according to the resistance value provided by the resistance sensing device.

[0009] Optionally, it also includes a moving structure for controlling the two contact probes to slide along the radial direction of the silicon wafer on the corresponding surfaces of the silicon wafer during the process of grinding the silicon wafer by the double-sided grinding equipment.

[0010] Optionally, when the two contact probes are in contact with corresponding surfaces of the silicon wafer respectively, the contact probes are arranged perpendicular to the corresponding surfaces of the silicon wafer, and a line connecting the two contact probes is arranged perpendicular to the silicon wafer.

[0011] Optionally, a rolling element is arranged at one end of the contact probe that contacts the silicon wafer.

[0012] Optionally, the rolling element includes a conductive ball.

[0013] Optionally, the mobile structure includes:

[0014] Two housings arranged opposite to each other;

[0015] A first driving part, located in the housing;

[0016] A transmission part, comprising two transmission rods respectively connected to the two contact probes, one end of the transmission rod being connected to the corresponding housing, and the other end of the transmission rod being provided with the contact probe;

[0017] Under the transmission action of the transmission part, the first driving part drives the contact probe to slide synchronously on the corresponding surface of the silicon wafer along the radial direction of the silicon wafer.

[0018] Optionally, the moving structure further includes a second driving unit located in the housing, and under the transmission action of the transmission unit, the second driving unit drives the contact probe to perform an opening and closing movement to contact the surface of the silicon wafer.

[0019] Optionally, the moving structure includes a speed regulating unit for controlling the sliding speed of the contact probe on the surface of the silicon wafer.

[0020] Optionally, a single stroke of the contact probe sliding on the surface of the silicon wafer along the radial direction of the silicon wafer is smaller than the radius of the silicon wafer, and the difference between a single stroke of the contact probe sliding on the surface of the silicon wafer along the radial direction of the silicon wafer and the radius of the silicon wafer is 5-10mm.

[0021] The embodiment of the present invention further provides a silicon wafer thickness measurement method, which is applied to the above-mentioned silicon wafer thickness measurement device, and the measurement method includes:

[0022] During the process of grinding the silicon wafer by the double-side grinding device, the two contact probes are controlled so that the two contact probes are respectively located on two opposite sides of the silicon wafer and respectively contact with corresponding surfaces of the silicon wafer;

[0023] Controlling two contact probes to move back and forth on the surface of the silicon wafer along the radial direction of the silicon wafer;

[0024] The resistance sensing device senses the resistance value of the silicon chip in real time;

[0025] The thickness of the silicon wafer is obtained according to the resistance value of the silicon wafer obtained in real time by the resistance sensing device.

[0026] The beneficial effects of the present invention are as follows: the silicon wafer thickness measuring device provided by the present invention comprises two contact probes, the two contact probes are respectively in contact with two opposite surfaces of a silicon wafer to measure the thickness of the silicon wafer, and when measuring the thickness of the silicon wafer, the two contact probes can slide on the surface of the silicon wafer along the radial direction of the silicon wafer, thereby increasing the contact area between the contact probe and the silicon wafer, reducing the fluctuation of the silicon wafer thickness measurement, and improving the measurement accuracy of the silicon wafer thickness. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of a double-sided grinding device is shown;

[0028] Figure 2 A schematic diagram showing the principle of silicon wafer thickness measurement in an embodiment of the present invention;

[0029] Figure 3 A schematic diagram showing a silicon wafer thickness measuring device in an embodiment of the present invention;

[0030] Figure 4 A schematic diagram showing a silicon wafer thickness measurement state in an embodiment of the present invention;

[0031] Figure 5 Schematic diagram showing the measurement trace on the silicon wafer. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0033] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure should be understood by people with ordinary skills in the field to which the present disclosure belongs. The "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, similar words such as "one", "one" or "the" do not indicate quantity restrictions, but indicate that there is at least one. Similar words such as "include" or "comprise" mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Similar words such as "connect" or "connected" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0034] The features such as "parallel", "perpendicular", and "same" used in the embodiments of the present disclosure include the features such as "parallel", "perpendicular", and "same" in a strict sense, as well as the cases where "approximately parallel", "approximately perpendicular", "approximately the same", etc. include certain tolerances, taking into account the tolerances associated with the measurement of specific quantities (e.g., the limitations of the measurement system), and represent the acceptable deviation range for a specific value determined by ordinary technicians in the field. For example, "approximately" can mean within one or more standard deviations, or within 3% or 5% of the value.

[0035] The measurement track of the silicon wafer thickness measurement device currently used on the silicon wafer surface is a circle with the same center as the silicon wafer. If the probe measurement method is adopted, the probe is fixed. Due to the rotation of the silicon wafer, the measurement track of the probe on the silicon wafer surface forms a circular track with the same center as the silicon wafer. The measurement track covers a small area of ​​the silicon wafer surface. This measurement method causes large fluctuations in the thickness of the silicon wafer processed by the double-disc grinder and cannot be well connected with the back-end process.

[0036] refer to Figure 2-Figure 5 In view of the above problems, this embodiment provides a silicon wafer thickness measuring device for measuring the thickness of the silicon wafer in real time during the double-sided grinding process. The silicon wafer thickness measuring device in this embodiment includes two contact probes 12, a resistance sensing device 13 and a processing unit 14.

[0037] The two contact probes 12 can respectively contact two opposite surfaces of the silicon wafer, and can respectively slide on the corresponding surfaces of the silicon wafer 10 along the radial direction of the silicon wafer 10;

[0038] The resistance sensing device 13 is used to be electrically connected to the two contact probes 12, and to obtain the resistance value of the silicon wafer 10 in real time when the two contact probes 12 are in contact with two opposite surfaces of the silicon wafer 10 respectively;

[0039] The processing unit 14 is used to obtain the thickness of the silicon wafer 10 according to the resistance value provided by the resistance sensing device 13 .

[0040] The silicon wafer 10 is a conductor, and the resistance of the silicon wafer 10 is different when the thickness is different. The silicon wafer 10 thickness measuring device provided by the present invention includes two contact probes 12, and the two contact probes 12 are in contact with two opposite surfaces of the silicon wafer 10 respectively, and the resistance value of the corresponding position of the silicon wafer 10 is obtained in real time through the resistance sensing device 13. The processing unit 14 obtains the thickness value of the silicon wafer 10 according to the resistance value sensed by the resistance sensing device 13, so as to measure the thickness of the silicon wafer 10 in real time. When measuring the thickness of the silicon wafer 10, the two contact probes 12 can slide on the surface of the silicon wafer 10 along the radial direction of the silicon wafer 10, and form a spiral measurement track on the surface of the silicon wafer 10 as the silicon wafer 10 rotates (refer to Figure 5 , Figure 5 The spiral line 100 in the figure is the measurement track of the contact probe 12 ), which increases the contact area between the contact probe 12 and the silicon wafer 10 , reduces the fluctuation of the thickness measurement of the silicon wafer 10 , and improves the measurement accuracy of the thickness of the silicon wafer 10 .

[0041] It should be noted that, as the contact probe 12 moves and the silicon wafer 10 rotates, the processing unit 14 acquires multiple resistance values ​​in real time, and processes the acquired resistance values ​​in real time to obtain the thickness measurement value of the silicon wafer 10 in real time. When the acquired thickness value of the silicon wafer 10 is a preset thickness, the double-sided grinding equipment can be controlled to stop grinding the silicon wafer 10.

[0042] In an exemplary embodiment, a plurality of resistance values ​​are obtained each time the silicon wafer 10 rotates one circle. The processing unit 14 can process the plurality of resistance values ​​obtained when the silicon wafer 10 rotates one circle to obtain the thickness value of the silicon wafer 10 after one circle of grinding. When the obtained thickness value of the silicon wafer 10 is a preset thickness, the double-sided grinding equipment can be controlled to stop grinding the silicon wafer 10.

[0043] When measuring the thickness of the silicon wafer 10, the contact probe 12 moves from the edge of the silicon wafer 10 to the center of the silicon wafer 10, and from the center of the silicon wafer 10 to the edge of the silicon wafer 10, and so on, along the radial direction of the silicon wafer 10. When obtaining the thickness of the silicon wafer 10, the processing unit 14 obtains a plurality of resistance values ​​in the process of the contact probe 12 moving from the edge of the silicon wafer 10 to the first position close to the center of the silicon wafer 10 (the position is the end point when the contact probe 12 moves from the edge of the silicon wafer 10 to the center of the silicon wafer 10), and obtains the thickness measurement value of the silicon wafer 10 according to the plurality of resistance values, and obtains a plurality of resistance values ​​in the process of moving from the first position to the edge of the silicon wafer 10 and moving to the edge of the silicon wafer 10, and obtains the thickness measurement value of the silicon wafer 10 according to the plurality of resistance values, and when the obtained thickness measurement value of the silicon wafer 10 is a preset value, the double-sided grinding device is controlled to provide grinding for the silicon wafer 10.

[0044] It should be noted that in order to obtain more resistance values ​​to improve the accuracy of measuring the thickness of the silicon wafer 10 , the speed of the contact probe 12 can be increased to increase the total stroke of the contact probe 12 and thereby increase the contact area between the contact probe 12 and the silicon wafer 10 .

[0045] In an exemplary embodiment, the silicon wafer 10 thickness measuring device further includes a moving structure 11 for controlling the two contact probes 12 to slide along the radial direction of the silicon wafer 10 on corresponding surfaces of the silicon wafer 10 during grinding of the silicon wafer 10 by a double-sided grinding device.

[0046] During the movement of the contact probe 12 , the contact probe 12 maintains contact with the silicon wafer 10 , so as to measure the thickness of the silicon wafer 10 .

[0047] It should be noted that the measurement of the thickness of the silicon wafer 10 by the silicon wafer 10 thickness measuring device provided in this embodiment is performed during the grinding process. In the double-sided grinding process, the diameter of the grinding wheel 2 is generally equal to the radius of the silicon wafer 10. In order to avoid affecting the grinding of the silicon wafer 10, in the radial direction of the silicon wafer 10, the shortest distance between the contact position of the two contact probes 12 and the silicon wafer 10 and the center of the silicon wafer 10 is 5-10 mm.

[0048] In an exemplary embodiment, when the two contact probes 12 are in contact with corresponding surfaces of the silicon wafer 10 respectively, the contact probes 12 are arranged perpendicular to the corresponding surfaces of the silicon wafer 10 , and a line connecting the two contact probes 12 is arranged perpendicular to the silicon wafer 10 .

[0049] In an exemplary embodiment, a rolling element is disposed at one end of the contact probe 12 that is in contact with the silicon wafer 10 .

[0050] The provision of the rolling element facilitates the contact probe 12 to slide on the surface of the silicon wafer 10 and prevents the contact probe 12 from damaging the surface of the silicon wafer 10 and causing scratches.

[0051] In an exemplary embodiment, since the silicon wafer 10 thickness measuring device provided in this embodiment measures the thickness of the silicon wafer 10 during the grinding process, that is, the thickness of the silicon wafer 10 changes, in order to ensure that the contact probe 12 always maintains contact with the surface of the silicon wafer 10 during the measurement process, the contact probe 12 includes a main body, the rolling element is arranged at one end of the main body, and a pressure sensor is arranged between the rolling element and the main body, and the position of the contact probe 12 is adjusted in real time according to the pressure value sensed by the pressure sensor.

[0052] Exemplarily, an elastic member may be disposed between the rolling member and the pressure sensor so that the rolling member has a moving space in the axial direction of the main body, so as to facilitate sensing of the pressure between the contact probe 12 and the silicon wafer 10 .

[0053] Exemplarily, the elastic member may be a spring.

[0054] In an exemplary embodiment, the rolling element includes a conductive ball, and may also be a conductive roller.

[0055] It should be noted that the rolling element is made of a conductive material that will not damage or contaminate the silicon wafer 10 .

[0056] In an exemplary embodiment, the mobile structure 11 includes two oppositely disposed shells 21 , a first driving part located in the shells 21 , a transmission part connected to the first driving part, and the contact probe 12 is disposed on the transmission part.

[0057] The resistance sensing device 13 and the processing unit 14 are both disposed in the housing 21 . Of course, the resistance sensing device 13 and the processing unit 14 may also be disposed outside the housing 21 .

[0058] The first driving unit may be a driving motor.

[0059] The transmission part includes two transmission rods 22 respectively connected to the two contact probes 12 , one end of the transmission rod 22 is connected to the corresponding housing 21 , and the contact probe 12 is arranged at the other end of the transmission rod 22 .

[0060] The two transmission rods 22 and the two shells 21 are arranged in a one-to-one correspondence, one end of the shell 21 extends outward to form a connecting portion, a first mounting hole is arranged on the connecting portion, and a second mounting hole is arranged at one end of the transmission rod 22, the first mounting hole and the second mounting hole cooperate to allow a bolt 23 to pass through, so as to fix the transmission rod 22 to the shell 21.

[0061] Under the transmission action of the transmission part, the first driving part drives the contact probe 12 to slide synchronously on the corresponding surface of the silicon wafer 10 along the radial direction of the silicon wafer 10 .

[0062] In order to improve the accuracy of measuring the thickness of the silicon wafer 10, the contact probe 12 is arranged perpendicular to the silicon wafer 10, and the line connecting the two contact probes 12 is perpendicular to the silicon wafer 10, that is, the line connecting the contact points of the two contact probes 12 with the corresponding surfaces of the silicon wafer 10 is arranged perpendicular to the silicon wafer 10.

[0063] It should be noted that the first driving unit drives the contact probes 12 to slide synchronously on the corresponding surface of the silicon wafer 10 along the radial direction of the silicon wafer 10. During the sliding process, the two contact probes 12 always keep in contact with the silicon wafer 10.

[0064] It should be noted that the connection position relationship between the transmission rod 22, the housing 21, and the first driving unit is not limited to the above. In some embodiments, the first driving unit is disposed in the housing 21 to realize the movement control of the contact probe 12. The first driving unit can be a cylinder, and one end of the transmission rod 22 is inserted into the interior of the housing 21 to be connected to the cylinder.

[0065] For example, the maximum moving stroke of the contact probe 12 in the first direction (i.e., the direction from the edge of the silicon wafer 10 to the center of the silicon wafer 10) can be limited by the length of the transmission rod 22. In order to avoid affecting the grinding of the silicon wafer 10, the contact probe 12 moves from the edge of the silicon wafer 10 to the center of the silicon wafer 10 and then stops at the first position. In the radial direction of the silicon wafer 10, the distance from the edge of the silicon wafer 10 to the first position (reference Figure 4 The A position in Figure 4 The dotted arrow in the figure is the sliding direction of the contact probe on the silicon wafer) is less than the radius of the silicon wafer 10. Under the control of the cylinder, the transmission rod 22 moves to a position close to the center of the silicon wafer 10. When the moving distance of the transmission rod 22 is at the maximum movable distance, the contact probe 12 moves to the first position.

[0066] In an exemplary embodiment, the limit of the moving position of the contact probe 12 can also be limited by the moving time.

[0067] In an exemplary embodiment, under the driving action of the first driving unit, the contact probe 12 can move uniformly along the radial direction of the silicon wafer 10 at a preset speed, or can accelerate along the radial direction of the silicon wafer 10 at a preset acceleration.

[0068] In an exemplary embodiment, the moving structure 11 further includes a second driving unit located in the housing 21 . Under the transmission action of the transmission unit, the second driving unit drives the contact probe 12 to perform an opening and closing movement to contact the surface of the silicon wafer 10 .

[0069] In some embodiments, the first driving unit is disposed outside the shell 21, and the first driving unit and the shell 21 are connected via a transmission component. The first driving unit controls the two shells 21 to move toward or away from each other, so as to control the two transmission rods 22 to move toward or away from each other, thereby making the two contact probes 12 contact the corresponding surfaces of the silicon wafer 10 respectively, or making the two contact probes 12 stay away from the corresponding surfaces of the silicon wafer 10 respectively.

[0070] It should be noted that when the first driving unit controls the two housings 21 to move toward or away from each other, so as to control the two transmission rods 22 to move toward or away from each other, and further controls the two contact probes 12 to move toward or away from each other, the movement direction of the two contact probes 12 is perpendicular to the silicon wafer 10. The two contact probes 12 may move synchronously, or one of the two contact probes 12 may move.

[0071] In an exemplary embodiment, the moving structure 11 includes a speed regulating unit for controlling the sliding speed of the contact probe 12 on the surface of the silicon wafer 10 .

[0072] The adjustment portion may include a differential motor.

[0073] It should be noted that, during the grinding process of the silicon wafer 10, the more thickness values ​​of the silicon wafer 10 obtained, the higher the accuracy of the thickness measurement of the silicon wafer 10, and the grinding time of the silicon wafer 10 is also limited. In this regard, the moving speed of the contact probe 12 in the radial direction of the silicon wafer 10 can be adjusted according to the grinding time of the silicon wafer 10.

[0074] In some embodiments, when the silicon wafer 10 is ground once, the contact probe 12 moves back and forth at least once in the radial direction of the silicon wafer 10 , but the present invention is not limited thereto.

[0075] In an exemplary embodiment, a single stroke of the contact probe 12 sliding on the surface of the silicon wafer 10 along the radial direction of the silicon wafer 10 is smaller than the radius of the silicon wafer 10, and a difference between a single stroke of the contact probe 12 sliding on the surface of the silicon wafer 10 along the radial direction of the silicon wafer 10 and the radius of the silicon wafer 10 is 5-10 mm. This prevents the measurement of the thickness of the silicon wafer 10 from affecting the grinding of the silicon wafer 10.

[0076] It should be noted that the contact probe 12 slides on the surface of the silicon wafer 10 along the radial direction of the silicon wafer 10, and the contact probe 12 moves back and forth between a first preset position and a second preset position (the first preset position is set close to the edge of the silicon wafer 10, the second preset position is set close to the center of the silicon wafer 10, and the line connecting the first preset position and the second preset position is parallel to the radial direction of the silicon wafer 10). The stroke of the contact probe 12 moving from the first preset position to the second preset position, or the stroke of the contact probe 12 moving from the second preset position to the first preset position is a single stroke.

[0077] The embodiment of the present invention further provides a method for measuring the thickness of a silicon wafer 10, which is applied to the above-mentioned silicon wafer thickness measuring device. The measuring method includes:

[0078] During the process of grinding the silicon wafer 10 by the double-sided grinding device, the two contact probes 12 are controlled so that the two contact probes 12 are respectively located on opposite sides of the silicon wafer and respectively contact with corresponding surfaces of the silicon wafer 10;

[0079] Controlling the two contact probes 12 to move back and forth on the surface of the silicon wafer 10 along the radial direction of the silicon wafer 10;

[0080] The resistance sensing device 13 senses the resistance value of the silicon chip 10 in real time;

[0081] The thickness of the silicon wafer 10 is obtained according to the resistance value of the silicon wafer 10 obtained in real time by the resistance sensing device 13 .

[0082] It should be noted that the measurement of the thickness of the silicon wafer 10 is performed during the grinding process of the silicon wafer 10. When the thickness value of the silicon wafer 10 obtained by the processing unit 14 is a preset thickness value, the double-sided grinding equipment can be controlled to stop grinding the silicon wafer 10. At this time, the measurement of the thickness of the silicon wafer 10 is stopped after the grinding of the silicon wafer 10 is completed.

[0083] There are a few points to note:

[0084] (1) The drawings of the embodiments of the present disclosure only relate to the structures related to the embodiments of the present disclosure, and other structures may refer to the general design.

[0085] (2) For the sake of clarity, in the drawings used to describe the embodiments of the present disclosure, the thickness of layers or regions is exaggerated or reduced, that is, these drawings are not drawn according to the actual scale. It is understood that when an element such as a layer, film, region or substrate is referred to as being "on" or "under" another element, the element may be "directly" "on" or "under" the other element or there may be intermediate elements.

[0086] (3) In the absence of conflict, the embodiments of the present disclosure and the features therein may be combined with each other to obtain new embodiments.

[0087] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A silicon wafer thickness measuring device for measuring the thickness of a silicon wafer, characterized in that: include: Two contact probes, capable of respectively contacting two opposite surfaces of the silicon wafer and respectively sliding on corresponding surfaces of the silicon wafer in a radial direction of the silicon wafer; A resistance sensing device, used to be electrically connected to the two contact probes and to obtain the resistance value of the silicon wafer when the two contact probes are in contact with two opposite surfaces of the silicon wafer respectively; The processing unit is used to obtain the thickness of the silicon wafer according to the resistance value provided by the resistance sensing device.

2. The silicon wafer thickness measuring device according to claim 1, characterized in that: It also includes a moving structure for controlling the two contact probes to slide along the radial direction of the silicon wafer on the corresponding surface of the silicon wafer during the process of grinding the silicon wafer by the double-sided grinding equipment.

3. The silicon wafer thickness measuring device according to claim 1, characterized in that: When the two contact probes are in contact with corresponding surfaces of the silicon wafer respectively, the contact probes are arranged perpendicular to the corresponding surfaces of the silicon wafer, and the connecting line of the two contact probes is arranged perpendicular to the silicon wafer.

4. The silicon wafer thickness measuring device according to claim 1, characterized in that: The contact probe is used to set a rolling piece at one end in contact with the silicon wafer.

5. The silicon wafer thickness measuring device according to claim 4, characterized in that: The rolling element includes a conductive ball.

6. The silicon wafer thickness measuring device according to claim 2, characterized in that: The mobile structure comprises: Two housings arranged opposite to each other; A first driving part, located in the housing; A transmission part, comprising two transmission rods respectively connected to the two contact probes, one end of the transmission rod being connected to the corresponding housing, and the other end of the transmission rod being provided with the contact probe; Under the transmission action of the transmission part, the first driving part drives the contact probe to slide synchronously on the corresponding surface of the silicon wafer along the radial direction of the silicon wafer.

7. The silicon wafer thickness measuring device according to claim 6, characterized in that: The moving structure further comprises a second driving part located in the housing. Under the transmission action of the transmission part, the second driving part drives the contact probe to perform an opening and closing movement so as to contact the surface of the silicon wafer.

8. The silicon wafer thickness measuring device according to claim 6, characterized in that: The moving structure comprises a speed regulating part for controlling the sliding speed of the contact probe on the surface of the silicon wafer.

9. The silicon wafer thickness measuring device according to claim 1, characterized in that: A single sliding stroke of the contact probe on the surface of the silicon wafer along the radial direction of the silicon wafer is smaller than the radius of the silicon wafer, and the difference between a single sliding stroke of the contact probe on the surface of the silicon wafer along the radial direction of the silicon wafer and the radius of the silicon wafer is 5-10 mm.

10. A method for measuring silicon wafer thickness, characterized in that: The silicon wafer thickness measuring device according to any one of claims 1 to 9, wherein the measuring method comprises: During the process of grinding the silicon wafer by the double-side grinding device, the two contact probes are controlled so that the two contact probes are respectively located on two opposite sides of the silicon wafer and respectively contact with corresponding surfaces of the silicon wafer; Controlling two contact probes to move back and forth on the surface of the silicon wafer along the radial direction of the silicon wafer; The resistance sensing device senses the resistance value of the silicon chip in real time; The thickness of the silicon wafer is obtained according to the resistance value of the silicon wafer obtained in real time by the resistance sensing device.

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