Silicon wafer flatness adjusting system

Abstract

The invention provides a silicon wafer flatness adjusting system, and relates to the technical field of semiconductors, and the system comprises a silicon wafer conveying device which is used for receiving a first silicon wafer processed by a silicon wafer grinding device, and conveying the first silicon wafer to a silicon wafer storage device; the thickness measuring device is used for measuring the thickness value of the first silicon wafer in the process of conveying the first silicon wafer by the silicon wafer conveying device; and the control equipment is connected with the thickness measuring device, and the control equipment is used for generating flatness information of the first silicon wafer according to the thickness value of the first silicon wafer and adjusting the angle of a grinding wheel used for grinding the first silicon wafer in the silicon wafer grinding equipment according to the flatness information of the first silicon wafer. According to the invention, the flatness of the surface of the silicon wafer processed by the double-disc grinding machine can be obtained in time through the silicon wafer flatness adjusting system, and the angle of the grinding wheel is adjusted in time, so that the quality of the silicon wafer processed subsequently is ensured.

Description

Technical Field

[0001] The invention relates to the field of semiconductor technology, and in particular to a silicon wafer flatness adjustment system. Background Art

[0002] A double-disc grinder is a device specially used for thinning 12-inch silicon wafers. When the double-sided grinder is used to process the silicon wafer, the silicon wafer is placed in the grinding chamber of the grinder, and the two surfaces of the silicon wafer are simultaneously ground by the grinding wheel. However, the diameter of the grinding wheel in the existing double-disc grinder is generally smaller than the diameter of the silicon wafer. For example, the diameter of the grinding wheel used for grinding is about 16 mm, which is half the diameter of the silicon wafer. This results in the inability to effectively control the flatness of the silicon wafer surface after processing by the double-disc grinder, resulting in the problem of poor surface flatness of the silicon wafer.

[0003] In the prior art, it is impossible to detect the flatness of a silicon wafer ground by a double-disc grinder with poor flatness, and it is also impossible to adjust the double-disc grinder in time according to the flatness detection result. Summary of the invention

[0004] The embodiment of the present invention provides a silicon wafer flatness adjustment system to solve the problem in the prior art that the flatness of the silicon wafer surface processed by a double-disc grinder cannot be obtained and the double-disc grinder cannot be adjusted in time according to the flatness detection result.

[0005] To solve the above technical problems, the embodiments of the present invention provide the following technical solutions:

[0006] An embodiment of the present invention provides a silicon wafer flatness adjustment system, which is arranged between a silicon wafer grinding device and a silicon wafer storage device;

[0007] The silicon wafer flatness adjustment system comprises:

[0008] A silicon wafer conveying device, used for receiving the first silicon wafer processed by the silicon wafer grinding device, and conveying the first silicon wafer to the silicon wafer receiving device;

[0009] A thickness measuring device, the thickness measuring device is disposed between the silicon wafer grinding device and the silicon wafer receiving device, and the thickness measuring device is used to measure the thickness value of the first silicon wafer during the process of the first silicon wafer being conveyed by the silicon wafer conveying device;

[0010] A control device, wherein the control device is connected to the thickness measuring device, and the control device is used to generate flatness information of the first silicon wafer according to the thickness value of the first silicon wafer, and adjust the angle of the grinding wheel in the silicon wafer grinding device for grinding the first silicon wafer according to the flatness information of the first silicon wafer.

[0011] In some embodiments, the thickness measuring device is used to measure the thickness value of a first diameter on the first silicon wafer during the process of the silicon wafer conveying device conveying the first silicon wafer; the thickness value of the first diameter includes the thickness values ​​of the first silicon wafer at multiple measuring points of the first diameter, and the first diameter is any diameter on the first silicon wafer;

[0012] The control device is used to generate flatness information of the first silicon wafer according to the thickness value of the first diameter.

[0013] In some embodiments, the thickness measuring device comprises: two measuring probes arranged opposite to each other in a vertical direction;

[0014] One of the two measuring probes is in contact with the upper surface of the first silicon wafer, and the other of the two measuring probes is in contact with the lower surface of the first silicon wafer;

[0015] The two measuring probes are used to measure the thickness of the first silicon wafer by measuring the fluctuations of the measuring probes on the surface of the first silicon wafer during the process of the silicon wafer conveying device conveying the first silicon wafer.

[0016] In some embodiments, the measuring probe contacts the surface of the first silicon wafer via a sliding ball.

[0017] In some embodiments, the thickness measuring device further comprises: a resistive displacement sensor;

[0018] The resistive displacement sensor is connected to the two measuring probes respectively;

[0019] During the process of the silicon wafer conveying device conveying the first silicon wafer, the resistive displacement sensor is used to convert the fluctuations of the two measuring probes on the surface of the first silicon wafer into electrical signals, and the electrical signals are used to indicate the thickness value of the first silicon wafer.

[0020] In some embodiments, the resistive displacement sensor includes: a resistor, a slider, and two probe connecting rods;

[0021] The slider is capable of sliding on the resistor;

[0022] Each of the measuring probes is connected to the slider via a probe connecting rod;

[0023] During the process of the silicon wafer conveying device conveying the first silicon wafer, the ups and downs of the two measuring probes on the surface of the first silicon wafer drive the movement of the probe connecting rod, and the movement of the probe connecting rod drives the slider to slide on the resistor. The slider generates an electrical signal, and the electrical signal is used to indicate the thickness value of the first silicon wafer.

[0024] In some embodiments, the flatness information of the first silicon wafer is used to indicate at least one of the following:

[0025] The difference between the thickness value of the central portion of the first silicon wafer and the thickness value of the edge portion of the first silicon wafer is less than a first preset value;

[0026] The thickness of the center portion of the first silicon wafer is greater than the thickness of the edge portion of the first silicon wafer, and the difference between the thickness of the center portion and the thickness of the edge portion is greater than a second preset value;

[0027] The thickness of the center portion of the first silicon wafer is smaller than the thickness of the edge portion of the first silicon wafer, and the difference between the thickness of the center portion and the thickness of the edge portion is greater than a third preset value.

[0028] In some embodiments, the silicon wafer grinding device includes a first grinding wheel and a second grinding wheel;

[0029] The first grinding wheel is used to grind the first surface of the first silicon wafer, and the second grinding wheel is used to grind the second surface of the first silicon wafer; the first surface and the second surface are two opposite surfaces of the first silicon wafer;

[0030] The diameter of the first grinding wheel is equal to the radius of the first silicon wafer, and the diameter of the second grinding wheel is equal to the radius of the first silicon wafer;

[0031] When the first grinding wheel grinds the first surface, the second diameter on the first grinding wheel covers the radius of the first surface; the second diameter is any diameter on the first grinding wheel;

[0032] When the second grinding wheel grinds the second surface, the third diameter on the second grinding wheel covers the radius of the second surface; the third diameter is any diameter on the second grinding wheel;

[0033] Wherein, the silicon wafer flatness adjustment system further comprises: a first driving device connected to the control device;

[0034] The first driving device is also connected to the first grinding wheel and the second grinding wheel respectively;

[0035] In a case where the thickness value of the center portion of the first silicon wafer is greater than the thickness value of the edge portion of the first silicon wafer, and the difference between the thickness value of the center portion and the thickness value of the edge portion is greater than a second preset value, the control device is used to send a first control signal to the first driving device, wherein the first control signal is used to instruct the first driving device to adjust the angles of the first grinding wheel and the second grinding wheel by reducing the distance between the first end of the second diameter and the first end of the third diameter, and increasing the distance between the second end of the second diameter and the second end of the third diameter;

[0036] In a case where the thickness value of the center portion of the first silicon wafer is smaller than the thickness value of the edge portion of the first silicon wafer, and the difference between the thickness value of the center portion and the thickness value of the edge portion is greater than a third preset value, the control device is used to send a second control signal to the first driving device, wherein the second control signal is used to instruct the first driving device to adjust the angles of the first grinding wheel and the second grinding wheel by increasing the distance between the first end of the second diameter and the first end of the third diameter, and decreasing the distance between the second end of the second diameter and the second end of the third diameter;

[0037] Wherein, the first end of the second diameter is an end of the second diameter covering the center of the first surface, and the first end of the third diameter is an end of the third diameter covering the center of the second surface;

[0038] The second end of the second diameter is the other end of the edge of the second diameter covering the first surface, and the second end of the third diameter is the other end of the edge of the third diameter covering the second surface.

[0039] In some embodiments, the silicon wafer conveying device includes: a second driving device and a conveyor belt connected to the second driving device;

[0040] The second driving device drives the conveyor belt to move between the silicon wafer grinding device and the silicon wafer storage device;

[0041] The conveyor belt contacts a first chord and a second chord on the lower surface of the first silicon wafer respectively, and the first silicon wafer is stationary relative to the conveyor belt due to the friction between the conveyor belt and the first chord and the friction between the conveyor belt and the second chord.

[0042] In some embodiments, the silicon wafer flatness adjustment system further includes: a cleaning chamber and an air knife;

[0043] Wherein, the cleaning chamber is located between the silicon wafer grinding equipment and the thickness measuring device, and the air knife is arranged between the cleaning chamber and the thickness measuring device;

[0044] The cleaning chamber is used for cleaning the first silicon wafer processed by the silicon wafer grinding equipment, and the air knife is used for drying the first silicon wafer after cleaning.

[0045] The embodiments of the present invention have the following beneficial effects:

[0046] A silicon wafer flatness adjustment system provided in an embodiment of the present invention is arranged between a silicon wafer grinding device (the silicon wafer grinding device can be a double-disc grinder) and a silicon wafer storage device. The silicon wafer flatness adjustment system receives a first silicon wafer processed by the silicon wafer grinding device through a silicon wafer conveying device, and transmits the first silicon wafer to the silicon wafer storage device. During the transmission of the first silicon wafer, a thickness value of the first silicon wafer is measured by a thickness measuring device, and the thickness measuring device sends the thickness value of the first silicon wafer to a control device. The control device generates flatness information of the first silicon wafer according to the thickness value of the first silicon wafer. According to the flatness information, the flatness of the processed first silicon wafer can be obtained in time. The control device can also adjust the angle of the grinding wheel used for grinding the first silicon wafer in the silicon wafer grinding device according to the flatness information of the first silicon wafer, so as to timely adjust the angle of the grinding wheel when the flatness of the silicon wafer does not meet the requirements, thereby ensuring the quality of the subsequently processed silicon wafers. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 A schematic diagram showing the structure of a silicon wafer flatness adjustment system provided by an embodiment of the present invention;

[0048] Figure 2 A schematic diagram showing a measurement of a thickness value of a first diameter measured by a thickness measuring device provided in an embodiment of the present invention;

[0049] Figure 3 A top view showing a thickness measuring device provided by an embodiment of the present invention;

[0050] Figure 4 One of the schematic diagrams of grinding wheel adjustment provided by an embodiment of the present invention is shown;

[0051] Figure 5 The second schematic diagram of the grinding wheel adjustment provided in the embodiment of the present invention is shown.

[0052] Reference numerals:

[0053] 1: silicon wafer conveying device; 2: first silicon wafer; 3: thickness measuring device; 31: measuring probe; 32: sensor; 33: resistive displacement sensor; 331: resistor; 332: slider; 333: probe connecting rod; 4: first grinding wheel; 5: second grinding wheel; 6: cleaning chamber; 7: air knife. DETAILED DESCRIPTION

[0054] In order to make the technical problems, technical solutions and advantages to be solved by the embodiments of the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0055] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0056] In order to solve the problem in the prior art that the flatness of the silicon wafer surface processed by the double disc grinder cannot be obtained and the double disc grinder cannot be adjusted in time according to the flatness detection result, an embodiment of the present invention provides a silicon wafer flatness adjustment system.

[0057] like Figure 1 As shown, an embodiment of the present invention provides a silicon wafer flatness adjustment system, wherein the silicon wafer flatness adjustment system is arranged between a silicon wafer grinding device and a silicon wafer receiving device; the silicon wafer grinding device and the silicon wafer receiving device are arranged between Figure 1 Not shown in the figure.

[0058] The silicon wafer grinding device may be a double-disc grinder, a single-side grinder, etc. In this embodiment, the silicon wafer grinding device is a double-disc grinder as an example for description.

[0059] The silicon wafer storage device may be a silicon wafer storage box.

[0060] The silicon wafer flatness adjustment system comprises:

[0061] The silicon wafer conveying device 1 is used to receive the first silicon wafer 2 processed by the silicon wafer grinding equipment and convey the first silicon wafer 2 to the silicon wafer storage device, that is, the silicon wafer conveying device 1 is used to transfer the first silicon wafer, which can be any silicon wafer or the first N silicon wafers processed by the silicon wafer grinding equipment, where N is a positive integer.

[0062] The silicon wafer flatness adjustment system further includes:

[0063] A thickness measuring device 3 is provided between the silicon wafer grinding device and the silicon wafer storage device, and is used to measure the thickness value of the first silicon wafer 2 during the process of the first silicon wafer 2 being transported by the silicon wafer conveying device.

[0064] That is, after the silicon wafer grinding device processes the first silicon wafer 2, the thickness value of the first silicon wafer 2 is obtained in time during the process of being transferred to the silicon wafer storage device, so as to avoid the problem that only after a batch or a box of silicon wafers are ground, other separate measuring devices are needed to measure the thickness of the entire batch of silicon wafers. The thickness measuring device 3 of the embodiment of the present invention can obtain the thickness value of a single silicon wafer in time, and the thickness value can timely feedback the processing quality of the silicon wafer by the silicon wafer grinding device.

[0065] A control device, wherein the control device is connected to the thickness measuring device 3, and the control device is used to generate flatness information of the first silicon wafer 2 according to the thickness value of the first silicon wafer 2, and adjust the angle of the grinding wheel used for grinding the first silicon wafer 2 in the silicon wafer grinding device according to the flatness information of the first silicon wafer 2.

[0066] Specifically, after the thickness measuring device 3 measures the thickness value of the first silicon wafer 2, it sends the thickness value of the first silicon wafer 2 to the control device. The control device receives the thickness value of the first silicon wafer 2 and sorts the thickness value of the first silicon wafer 2 to obtain the thickness change trend of the first silicon wafer 2. The change trend indicates the flatness information of the first silicon wafer.

[0067] When it is determined based on the flatness information of the first silicon wafer that the processed first silicon wafer does not meet the requirements, such as protrusion in the middle or at the edge, the control device adjusts the angle of the grinding wheel in the silicon wafer grinding device based on the flatness information of the first silicon wafer, so as to achieve timely adjustment of the grinding wheel and ensure the quality of the subsequently processed silicon wafers.

[0068] In some embodiments, the thickness measuring device 3 is used to measure the thickness value of a first diameter on the first silicon wafer 2 during the process of the silicon wafer conveying device conveying the first silicon wafer 2; the thickness value of the first diameter includes the thickness values ​​of the first silicon wafer 2 at multiple measuring points of the first diameter, and the first diameter is any diameter on the first silicon wafer 2;

[0069] The control device is used to generate flatness information of the first silicon wafer 2 according to the thickness value of the first diameter.

[0070] In order to avoid affecting the transmission of the first silicon wafer 2 and to ensure complete feedback of the flatness information of the first silicon wafer 2, in this embodiment, a thickness measuring device 3 is used to measure the thickness value of the first silicon wafer 2 at multiple measurement points of the first diameter, and the flatness information of the entire first silicon wafer 2 is reflected according to the thickness value of the first diameter. While ensuring the transmission efficiency, the accuracy of the flatness information of the first silicon wafer 2 can also be guaranteed.

[0071] The thickness measuring device 3 measures the thickness value of the measuring point through a measuring probe.

[0072] It can be understood that during the process of the thickness measuring device 3 measuring the thickness of the first diameter of the first silicon wafer 2, after the thickness measuring device 3 detects the first silicon wafer 2, the measuring probe on the thickness measuring device 3 is first aligned with the edge of the silicon wafer, and the thickness value of a measuring point on the edge of the silicon wafer is measured. After that, the first silicon wafer is driven to move by the silicon wafer conveying device 1. During the movement, it is ensured that the measuring probe on the thickness measuring device 3 is aligned with a diameter of the first silicon wafer 2 (the diameter is the first diameter), and the thickness value at each measuring point of the first diameter is measured one by one.

[0073] Furthermore, the first silicon wafer 2 may be positioned in advance to ensure that the measuring probe on the thickness measuring device 3 is aligned with a diameter of the first silicon wafer 2 during the conveyance of the first silicon wafer 2 .

[0074] The number of the measuring points can be preset, or can be determined according to the diameter (or size) of the first silicon wafer 2. The larger the diameter (or size) of the first silicon wafer 2, the more the number of measuring points, and the smaller the diameter (or size) of the first silicon wafer 2, the fewer the number of measuring points. Also, the distance between two adjacent measuring points can be preset. In order to ensure the accuracy of the flatness information of the first silicon wafer measured by thickness, the distance between the two measuring points can be as small as possible.

[0075] Furthermore, after the control device receives the thickness values ​​of multiple measurement points on the first diameter of the first silicon wafer 2, it can sort out the positions of different measurement points and the corresponding thickness values ​​to obtain the thickness value change trend from one end to the other end of the first diameter, and the change trend indicates the flatness information of the first silicon wafer.

[0076] Through the above structure, it is possible to obtain the flatness of the surface of the silicon wafer processed by the double-disc grinder through the silicon wafer flatness adjustment system.

[0077] Exemplarily, the control device generates a thickness variation curve of the first diameter according to the positions of different measurement points and the corresponding thickness values, and the flatness information of the first silicon wafer, that is, the flatness of the first silicon wafer after processing, can be obtained according to the thickness variation curve.

[0078] In the case where the first silicon wafer is the first N silicon wafers processed by the silicon wafer grinding equipment, after measuring the flatness of the first silicon wafer by the silicon wafer flatness adjustment system provided by the embodiment of the present invention, the flatness of the silicon wafer after the first silicon wafer is processed by the silicon wafer grinding equipment can be inferred, and after the control device adjusts the angle of the grinding wheel according to the flatness information, the flatness of the subsequently processed silicon wafers can be guaranteed to be qualified.

[0079] In some embodiments, the thickness measuring device 3 comprises: two measuring probes 31 arranged opposite to each other in the vertical direction;

[0080] One of the two measuring probes 31 is in contact with the upper surface of the first silicon wafer 2 , and the other of the two measuring probes 31 is in contact with the lower surface of the first silicon wafer 2 ;

[0081] The two measuring probes 31 are used to measure the thickness of the first silicon wafer 2 by measuring the fluctuations of the measuring probes 31 on the surface of the first silicon wafer 2 during the process of the silicon wafer conveying device 1 conveying the first silicon wafer 2 .

[0082] Optionally, by arranging two measuring probes 31 opposite to each other in the vertical direction, it can be ensured that the two measuring probes 31 measure the fluctuation of the surface of the first diameter of the first silicon wafer 2 , and the thickness value of the first diameter is obtained.

[0083] That is, the thickness value of the first diameter is obtained according to the fluctuation of the first diameter in the upper surface of the first silicon wafer 2 by the measuring probe 31 in contact with the upper surface of the first silicon wafer 2, and the fluctuation of the first diameter in the lower surface of the first silicon wafer 2 by the measuring probe 31 in contact with the lower surface of the first silicon wafer 2. Specifically, in this embodiment, the thickness value of each measuring point on the first diameter can be reflected by the distance value between the upper and lower surfaces of the first silicon wafer 2 corresponding to the measuring point.

[0084] The schematic diagram of measuring the thickness value of the first diameter by the thickness measuring device 3 is as follows: Figure 2 shown.

[0085] A sensor 32 can also be set in the thickness measuring device 3. The sensor 32 is used to sense the position of the first silicon wafer, for example, to sense whether the first silicon wafer 2 is close to the measuring probe 31 of the thickness measuring device 3, and whether the first silicon wafer 2 is in contact with the measuring probe 31. The sensor 32 can also move with the movement of the first silicon wafer 2, and then sense whether the first silicon wafer 2 is out of contact with the measuring probe 31 of the thickness measuring device 3, and whether the first silicon wafer 2 is away from the measuring probe 31.

[0086] Preferably, the measuring probe 31 contacts the surface of the first silicon wafer 2 through a sliding ball. That is, the measuring probe 31 contacts the first silicon wafer 2 slightly, and the end point of one contact end is a sliding ball, which can reduce the friction between the measuring probe and the surface of the first silicon wafer 2, reduce the resistance between the measuring probe and the surface of the first silicon wafer 2, and further reduce the impact on the transmission of the first silicon wafer 2.

[0087] For some examples, see Figure 3 , Figure 3 is a top view of the thickness measuring device 3, as shown in Figure 2 As shown, the thickness measuring device 3 further includes: a resistive displacement sensor 33;

[0088] The resistive displacement sensor 33 is connected to the two measuring probes 31 respectively;

[0089] During the process of the silicon wafer conveying device 1 conveying the first silicon wafer 2, the resistive displacement sensor 33 is used to convert the fluctuation changes of the two measuring probes 31 on the surface (or the first diameter) of the first silicon wafer 2 into an electrical signal, and the electrical signal is used to indicate the thickness value of the first silicon wafer 2 (or the first diameter) or different thickness values ​​can be calculated according to different values ​​of the electrical signal.

[0090] After obtaining the electrical signal indicating the thickness value of the first diameter on the first silicon wafer 2 through the resistive displacement sensor 33, the electrical signal is sent to the control device, and the control device obtains the flatness information of the first silicon wafer 2 based on the electrical signal, such as fitting the flatness curve of the first silicon wafer 2.

[0091] In this embodiment, the electrical signal obtained by the resistive displacement sensor 33 can not only obtain the flatness information of the first silicon wafer, but also be easily transmitted to the control device.

[0092] In some embodiments, such as Figure 3 As shown, the resistive displacement sensor 33 includes: a resistor 331, a slider 332 and two probe connecting rods 333;

[0093] The slider 332 can slide on the resistor 331;

[0094] Each of the measuring probes 31 is connected to the slider 332 via a probe connecting rod 333;

[0095] During the process of the silicon wafer conveying device 1 conveying the first silicon wafer 2, the ups and downs of the two measuring probes 31 on the surface of the first silicon wafer 2 drive the movement of the probe connecting rod 333, and the movement of the probe connecting rod 333 drives the slider 332 to slide on the resistor 331. The slider 332 generates an electrical signal, and the electrical signal is used to indicate the thickness value of the first silicon wafer 2.

[0096] Specifically, when the sensor 32 senses that the first silicon wafer 2 is transported to the designated position, the measuring probe 31 is closed at this position and can contact the edge of the first silicon wafer 2. At this designated position, the measuring probe 31 is controlled to close until it contacts the edge of the first silicon wafer 2. Afterwards, as the first silicon wafer 2 moves, the measuring probe 31 drives the probe connecting rod 333 to rotate as the flatness of the silicon wafer changes. The rotation of the probe connecting rod 333 drives the slider 332 to slide on the resistor 331. Through this process, the resistive displacement sensor 33 converts the flatness change signal of the silicon wafer into an electrical signal, and finally the control device fits the electrical signal into a silicon wafer flatness curve.

[0097] In some embodiments, the flatness information of the first silicon wafer is used to indicate at least one of the following:

[0098] a. a difference between a thickness value at a center portion of the first silicon wafer and a thickness value at an edge portion of the first silicon wafer is less than a first preset value;

[0099] b. The thickness of the center portion of the first silicon wafer is greater than the thickness of the edge portion of the first silicon wafer, and the difference between the thickness of the center portion and the thickness of the edge portion is greater than a second preset value;

[0100] c. The thickness of the center portion of the first silicon wafer is smaller than the thickness of the edge portion of the first silicon wafer, and the difference between the thickness of the center portion and the thickness of the edge portion is greater than a third preset value.

[0101] In the above indication information a, the difference between the thickness value of the center of the first silicon wafer and the thickness value of the edge of the first silicon wafer can be obtained by first taking the average value of the thickness values ​​of the measuring points in the center of the first silicon wafer and taking the average value of the thickness values ​​of the measuring points in the edge of the first silicon wafer, and taking the difference between the two average values ​​as the difference between the thickness value of the center of the first silicon wafer and the thickness value of the edge of the first silicon wafer. Alternatively, the thickness values ​​of M measuring points in the center of the first silicon wafer and the thickness values ​​of M measuring points in the edge of the first silicon wafer can be taken, and the difference between the thickness value of a measuring point in the center of the first silicon wafer and the thickness value of a corresponding measuring point in the edge of the first silicon wafer can be obtained in sequence one by one. When the difference between the thickness values ​​corresponding to each measuring point in the M measuring points is less than the first preset value, it is considered that the difference between the thickness value of the center of the first silicon wafer and the thickness value of the edge of the first silicon wafer is less than the first preset value.

[0102] Furthermore, the indication information a can also be understood as that the difference between the thickness value at the center of the first silicon wafer and the thickness value at the edge of the first silicon wafer is small, and the silicon wafer processed by the silicon wafer grinding equipment has good flatness.

[0103] In the above indication information b, the difference between the thickness value of the center of the first silicon wafer and the thickness value of the edge of the first silicon wafer can be obtained by first taking the average value of the thickness values ​​of the measuring points in the center of the first silicon wafer and taking the average value of the thickness values ​​of the measuring points in the edge of the first silicon wafer, and taking the difference between the two average values ​​as the difference between the thickness value of the center of the first silicon wafer and the thickness value of the edge of the first silicon wafer. Alternatively, the thickness values ​​of M measuring points in the center of the first silicon wafer and the thickness values ​​of M measuring points in the edge of the first silicon wafer can be taken, and the difference between the thickness value of a measuring point in the center of the first silicon wafer and the thickness value of a measuring point in the corresponding edge can be obtained in sequence. When the thickness value of each measuring point in the center of the first silicon wafer is greater than the thickness value of a measuring point in the corresponding edge, and the difference is greater than the second preset value, it is considered that the thickness value of the center of the first silicon wafer is greater than the thickness value of the edge of the first silicon wafer, and the difference between the thickness value of the edge and the thickness value of the edge is greater than the second preset value.

[0104] And the above indication information b can also be understood as that the thickness value of the center part of the first silicon wafer is larger than the thickness value of the edge part of the first silicon wafer, and the flatness characteristic of the silicon wafer processed by the silicon wafer grinding equipment is that the middle is convex upward.

[0105] In the above indication information c, the difference between the thickness value of the center of the first silicon wafer and the thickness value of the edge of the first silicon wafer can be obtained by first taking the average value of the thickness values ​​of the measuring points in the center of the first silicon wafer and taking the average value of the thickness values ​​of the measuring points in the edge of the first silicon wafer, and taking the difference between the two average values ​​as the difference between the thickness value of the center of the first silicon wafer and the thickness value of the edge of the first silicon wafer. Alternatively, the thickness values ​​of M measuring points in the center of the first silicon wafer and the thickness values ​​of M measuring points in the edge of the first silicon wafer can be taken, and the difference between the thickness value of a measuring point in the center of the first silicon wafer and the thickness value of a measuring point in the corresponding edge can be obtained in sequence. When the thickness value of each measuring point in the center of the first silicon wafer is less than the thickness value of a measuring point in the corresponding edge, and the difference is greater than the second preset value, it is considered that the thickness value of the center of the first silicon wafer is less than the thickness value of the edge of the first silicon wafer, and the difference between the thickness value of the center of the first silicon wafer and the thickness value of the edge is greater than the third preset value.

[0106] And the above indication information c can also be understood as that the thickness value of the center part of the first silicon wafer is larger than the thickness value of the edge part of the first silicon wafer, and the flatness characteristic of the silicon wafer processed by the silicon wafer grinding equipment is that it is concave in the middle.

[0107] In this embodiment, M is a positive integer, and the first preset value, the second preset value, and the third preset value may be equal or unequal, and their specific values ​​may be set according to requirements.

[0108] In some embodiments, the silicon wafer grinding device includes a first grinding wheel and a second grinding wheel;

[0109] The first grinding wheel is used to grind the first surface of the first silicon wafer, and the second grinding wheel is used to grind the second surface of the first silicon wafer; the first surface and the second surface are two opposite surfaces of the first silicon wafer;

[0110] The silicon wafer grinding device may be a device for grinding vertical silicon wafers or a device for grinding horizontal silicon wafers.

[0111] In the case where the silicon wafer grinding apparatus is an apparatus for grinding a horizontal silicon wafer, one of the first surface and the second surface is an upper surface, and the other is a lower surface.

[0112] The diameter of the first grinding wheel is equal to the radius of the first silicon wafer, and the diameter of the second grinding wheel is equal to the radius of the first silicon wafer;

[0113] When the first grinding wheel grinds the first surface, the second diameter on the first grinding wheel covers the radius of the first surface; the second diameter is any diameter on the first grinding wheel;

[0114] When the second grinding wheel grinds the second surface, the third diameter on the second grinding wheel covers the radius of the second surface; the third diameter is any diameter on the second grinding wheel.

[0115] That is, when grinding the silicon wafer with a grinding wheel, for each surface of the silicon wafer, after the corresponding grinding wheel covers any radius of its surface, the silicon wafer is controlled to rotate relative to the grinding wheel to achieve grinding of the silicon wafer surface.

[0116] Wherein, the silicon wafer flatness adjustment system further comprises: a first driving device connected to the control device;

[0117] The first driving device is also connected to the first grinding wheel and the second grinding wheel respectively;

[0118] When the thickness value of the center part of the first silicon wafer is greater than the thickness value of the edge part of the first silicon wafer, and the difference between the thickness value of the center part and the thickness value of the edge part is greater than a second preset value, the control device is used to send a first control signal to the first driving device, and the first control signal is used to instruct the first driving device to adjust the angle of the first grinding wheel and the second grinding wheel by reducing the distance between the first end of the second diameter and the first end of the third diameter, and increasing the distance between the second end of the second diameter and the second end of the third diameter; wherein the first end of the second diameter is an end of the second diameter covering the center of the first surface, and the first end of the third diameter is an end of the third diameter covering the center of the second surface; the second end of the second diameter is the other end of the second diameter covering the edge of the first surface, and the second end of the third diameter is the other end of the third diameter covering the edge of the second surface.

[0119] Take the silicon wafer grinding equipment as an example, which is a device for grinding vertical silicon wafers. Figure 4 As shown, when it is determined according to the flatness information of the first silicon wafer that the middle of the first silicon wafer processed by the silicon wafer grinding equipment is convex upward, the distance between the first grinding wheel 4 and the second grinding wheel 5 on both sides of the center of the silicon wafer is reduced, and the distance between the first grinding wheel 4 and the second grinding wheel 5 on both sides of the edge of the silicon wafer is increased, and the direction is adjusted as shown in FIG. Figure 4 As shown by the arrow in the figure, the flatness of the processed silicon wafer is adjusted.

[0120] When the thickness value of the center part of the first silicon wafer is smaller than the thickness value of the edge part of the first silicon wafer, and the difference between the thickness value of the center part and the thickness value of the edge part is greater than a third preset value, the control device is used to send a second control signal to the first driving device, and the second control signal is used to instruct the first driving device to adjust the angles of the first grinding wheel and the second grinding wheel by increasing the distance between the first end of the second diameter and the first end of the third diameter, and reducing the distance between the second end of the second diameter and the second end of the third diameter; wherein the first end of the second diameter is an end of the second diameter covering the center of the first surface, and the first end of the third diameter is an end of the third diameter covering the center of the second surface; the second end of the second diameter is the other end of the second diameter covering the edge of the first surface, and the second end of the third diameter is the other end of the third diameter covering the edge of the second surface.

[0121] Take the silicon wafer grinding equipment as an example, which is a device for grinding vertical silicon wafers. Figure 5As shown, when it is determined according to the flatness information of the first silicon wafer that the middle of the first silicon wafer processed by the silicon wafer grinding equipment is concave downward, the distance between the first grinding wheel 4 and the second grinding wheel 5 on both sides of the center of the silicon wafer is increased, and the distance between the first grinding wheel 4 and the second grinding wheel 5 on both sides of the edge of the silicon wafer is reduced, and the direction is adjusted as shown in FIG. Figure 5 As shown by the arrow in the figure, the flatness of the processed silicon wafer is adjusted.

[0122] When the difference between the thickness value of the center part of the first silicon wafer and the thickness value of the edge part of the first silicon wafer is less than the first preset value, it indicates that the distance between the first end of the second diameter and the first end of the third diameter, and the distance between the second end of the second diameter and the second end of the third diameter are appropriate, which can ensure a more appropriate grinding amount without the need for a grinding wheel angle.

[0123] It should be noted that in the control device, adjustment rules (or adjustment big data) are pre-stored. The adjustment rules (or adjustment big data) include adjustment direction and adjustment amount, which are obtained and stored by the control device based on historical data and adjustment experience.

[0124] After the above adjustments, the flatness of the silicon wafer processed by the silicon wafer grinding equipment is optimal, including the total thickness deviation (Total Thickness Variation, TTV), global back surface-referenced ideal plane / range (Global Backsurface-referenced Ideal plane / Range, GBIR), thickness, distortion (WARP), and warpage (BOW) are all in the best state.

[0125] When adjusting the distance between the grinding wheels, the center of the grinding wheel is used as the axis. By changing the vertical inclination of the grinding wheel when processing the silicon wafer, the grinding angle of the grinding wheel is adjusted to control the flatness of the silicon wafer.

[0126] In some embodiments, the silicon wafer conveying device 1 includes: a second driving device and a conveyor belt connected to the second driving device;

[0127] The second driving device drives the conveyor belt to move between the silicon wafer grinding device and the silicon wafer receiving device;

[0128] The conveyor belt contacts a first chord and a second chord on the lower surface of the first silicon wafer respectively, and the first silicon wafer is stationary relative to the conveyor belt due to the friction between the conveyor belt and the first chord and the friction between the conveyor belt and the second chord.

[0129] Wherein, both the first chord and the second chord are different from the first diameter.

[0130] That is, in this embodiment, the first silicon wafer is transported by two conveyor belts, which reduces the contact between the silicon wafer conveying device 1 and the first silicon wafer, avoids interference with the thickness measuring device 3, and affects the thickness measuring device 3 in measuring the thickness value of the first diameter.

[0131] Among them, the friction force between the conveyor belt and the first chord and the friction force between the conveyor belt and the second chord are much greater than the resistance (or friction force) between the measuring probe 31 and the surface of the first silicon wafer 2, which can ensure the stable transmission of the first silicon wafer 2, so that the measurement of the first silicon wafer 2 by the measuring probe 31 does not affect the transmission of the first silicon wafer 2.

[0132] Further, the first chord and the second chord are located on both sides of the first diameter, and the first chord and the second chord are symmetrical with respect to the first diameter.

[0133] That is, the two conveyor belts are in contact with the two chords symmetrical with the first diameter respectively, so as to ensure the stability of the first silicon wafer 2 during the transportation of the first silicon wafer.

[0134] In some embodiments, Figure 1 As shown, the silicon wafer flatness adjustment system further includes: a cleaning chamber 6 and an air knife 7;

[0135] The cleaning chamber 6 is located between the silicon wafer grinding equipment and the thickness measuring device 3, and the air knife 7 is arranged between the cleaning chamber 6 and the thickness measuring device 3;

[0136] The cleaning chamber 6 is used to clean the first silicon wafer 2 after being processed by the silicon wafer grinding equipment, and the air knife 7 is used to blow dry the first silicon wafer 2 after cleaning.

[0137] After the silicon wafer grinding device processes the first silicon wafer 2, a cleaning liquid is sprayed onto the first silicon wafer through the cleaning chamber 6 to clean the silicon wafer and ensure the cleanliness of the silicon wafer surface. Then, the water stains on the silicon wafer surface are blown away by the air knife 7 to avoid affecting the subsequent thickness measurement.

[0138] The blowing force of the wind knife 7 on the first silicon wafer 2 is smaller than the friction between the conveyor belt and the surface of the first silicon wafer, thereby preventing the first silicon wafer from being blown away.

[0139] The silicon wafer flatness adjustment system provided by the embodiment of the present invention also has the following advantages: when processing a whole box of silicon wafers, a few silicon wafers are first processed by silicon wafer grinding equipment, and then the silicon wafers are tested for flatness by the silicon wafer flatness adjustment system provided by the embodiment of the present invention. After the flatness information of the silicon wafers is obtained, the distance between the grinding wheels is adjusted according to the flatness information of the silicon wafers to ensure the flatness of the subsequently processed silicon wafers, avoid product quality loss caused by delayed adjustment, improve the stability of equipment production, improve the degree of automation of equipment, reduce the utilization loss caused by manual downtime adjustment, and improve the effect of silicon wafer flatness.

[0140] A comparison between the flatness parameters of silicon wafers produced before the angle and distance of the grinding wheel were improved by the above method (before improvement) and the flatness parameters of silicon wafers produced after the angle and distance of the grinding wheel were improved by the above method (before improvement) is shown in Table 1 below.

[0141] Table 1

[0142]

[0143] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A silicon wafer flatness adjustment system, characterized in that: Installed between the silicon wafer grinding equipment and the silicon wafer storage device; The silicon wafer flatness adjustment system comprises: A silicon wafer conveying device, used for receiving the first silicon wafer processed by the silicon wafer grinding device, and conveying the first silicon wafer to the silicon wafer receiving device; A thickness measuring device, the thickness measuring device is disposed between the silicon wafer grinding device and the silicon wafer receiving device, and the thickness measuring device is used to measure the thickness value of the first silicon wafer during the process of the first silicon wafer being conveyed by the silicon wafer conveying device; A control device, wherein the control device is connected to the thickness measuring device, and the control device is used to generate flatness information of the first silicon wafer according to the thickness value of the first silicon wafer, and adjust the angle of the grinding wheel in the silicon wafer grinding device for grinding the first silicon wafer according to the flatness information of the first silicon wafer.

2. The silicon wafer flatness adjustment system according to claim 1, characterized in that: The thickness measuring device is used to measure the thickness value of a first diameter on the first silicon wafer during the process of the silicon wafer conveying device conveying the first silicon wafer; the thickness value of the first diameter includes the thickness values ​​of the first silicon wafer at multiple measuring points of the first diameter, and the first diameter is any diameter on the first silicon wafer; The control device is used to generate flatness information of the first silicon wafer according to the thickness value of the first diameter.

3. The silicon wafer flatness adjustment system according to claim 1, characterized in that: The thickness measuring device comprises: two measuring probes arranged opposite to each other in the vertical direction; One of the two measuring probes is in contact with the upper surface of the first silicon wafer, and the other of the two measuring probes is in contact with the lower surface of the first silicon wafer; The two measuring probes are used to measure the thickness of the first silicon wafer by measuring the fluctuations of the measuring probes on the surface of the first silicon wafer during the process of the silicon wafer conveying device conveying the first silicon wafer.

4. The silicon wafer flatness adjustment system according to claim 3, characterized in that: The measuring probe contacts the surface of the first silicon wafer via a sliding ball.

5. The silicon wafer flatness adjustment system according to claim 3, characterized in that: The thickness measuring device further comprises: a resistive displacement sensor; The resistive displacement sensor is connected to the two measuring probes respectively; During the process of the silicon wafer conveying device conveying the first silicon wafer, the resistive displacement sensor is used to convert the fluctuations of the two measuring probes on the surface of the first silicon wafer into electrical signals, and the electrical signals are used to indicate the thickness value of the first silicon wafer.

6. The silicon wafer flatness adjustment system according to claim 5, characterized in that: The resistive displacement sensor comprises: a resistor, a slider and two probe connecting rods; The slider is capable of sliding on the resistor; Each of the measuring probes is connected to the slider via a probe connecting rod; During the process of the silicon wafer conveying device conveying the first silicon wafer, the ups and downs of the two measuring probes on the surface of the first silicon wafer drive the movement of the probe connecting rod, and the movement of the probe connecting rod drives the slider to slide on the resistor. The slider generates an electrical signal, and the electrical signal is used to indicate the thickness value of the first silicon wafer.

7. The silicon wafer flatness adjustment system according to claim 1, characterized in that: The flatness information of the first silicon wafer is used to indicate at least one of the following: The difference between the thickness value of the central portion of the first silicon wafer and the thickness value of the edge portion of the first silicon wafer is less than a first preset value; The thickness of the center portion of the first silicon wafer is greater than the thickness of the edge portion of the first silicon wafer, and the difference between the thickness of the center portion and the thickness of the edge portion is greater than a second preset value; The thickness of the center portion of the first silicon wafer is smaller than the thickness of the edge portion of the first silicon wafer, and the difference between the thickness of the center portion and the thickness of the edge portion is greater than a third preset value.

8. The silicon wafer flatness adjustment system according to claim 7, characterized in that: The silicon wafer grinding equipment comprises a first grinding wheel and a second grinding wheel; The first grinding wheel is used to grind the first surface of the first silicon wafer, and the second grinding wheel is used to grind the second surface of the first silicon wafer; the first surface and the second surface are two opposite surfaces of the first silicon wafer; The diameter of the first grinding wheel is equal to the radius of the first silicon wafer, and the diameter of the second grinding wheel is equal to the radius of the first silicon wafer; When the first grinding wheel grinds the first surface, the second diameter on the first grinding wheel covers the radius of the first surface; the second diameter is any diameter on the first grinding wheel; When the second grinding wheel grinds the second surface, the third diameter on the second grinding wheel covers the radius of the second surface; the third diameter is any diameter on the second grinding wheel; Wherein, the silicon wafer flatness adjustment system further comprises: a first driving device connected to the control device; The first driving device is also connected to the first grinding wheel and the second grinding wheel respectively; In a case where the thickness value of the center portion of the first silicon wafer is greater than the thickness value of the edge portion of the first silicon wafer, and the difference between the thickness value of the center portion and the thickness value of the edge portion is greater than a second preset value, the control device is used to send a first control signal to the first driving device, wherein the first control signal is used to instruct the first driving device to adjust the angles of the first grinding wheel and the second grinding wheel by reducing the distance between the first end of the second diameter and the first end of the third diameter, and increasing the distance between the second end of the second diameter and the second end of the third diameter; In a case where the thickness value of the center portion of the first silicon wafer is smaller than the thickness value of the edge portion of the first silicon wafer, and the difference between the thickness value of the center portion and the thickness value of the edge portion is greater than a third preset value, the control device is used to send a second control signal to the first driving device, wherein the second control signal is used to instruct the first driving device to adjust the angles of the first grinding wheel and the second grinding wheel by increasing the distance between the first end of the second diameter and the first end of the third diameter, and decreasing the distance between the second end of the second diameter and the second end of the third diameter; Wherein, the first end of the second diameter is an end of the second diameter covering the center of the first surface, and the first end of the third diameter is an end of the third diameter covering the center of the second surface; The second end of the second diameter is the other end of the edge of the second diameter covering the first surface, and the second end of the third diameter is the other end of the edge of the third diameter covering the second surface.

9. The silicon wafer flatness adjustment system according to claim 1, characterized in that: The silicon wafer conveying device comprises: a second driving device and a conveying belt connected to the second driving device; The second driving device drives the conveyor belt to move between the silicon wafer grinding device and the silicon wafer storage device; The conveyor belt contacts a first chord and a second chord on the lower surface of the first silicon wafer respectively, and the first silicon wafer is stationary relative to the conveyor belt due to the friction between the conveyor belt and the first chord and the friction between the conveyor belt and the second chord.

10. The silicon wafer flatness adjustment system according to claim 1, characterized in that: Also includes: Cleaning chamber and air knife; Wherein, the cleaning chamber is located between the silicon wafer grinding equipment and the thickness measuring device, and the air knife is arranged between the cleaning chamber and the thickness measuring device; The cleaning chamber is used for cleaning the first silicon wafer processed by the silicon wafer grinding equipment, and the air knife is used for drying the first silicon wafer after cleaning.

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