Silicon wafer backside inspection device and backside inspection method

Abstract

The present invention discloses a silicon wafer back-inspection device and a back-inspection method, in which a spiral guide rail seat is provided with a first groove spirally arranged from the center to the edge, one end of a connecting rod is connected to the center of the spiral guide rail seat through a rotating shaft, and the other end of the connecting rod makes a circular motion around the center of the spiral guide rail seat, a slider is sleeved on the connecting rod, a first roller is provided on a side of the slider adjacent to the first groove, and a visual inspection device is arranged on a side away from the first groove, wherein the first roller is at least partially provided in the first groove; a driving device is connected to the rotating shaft and is used to drive the connecting rod to rotate so as to drive the first roller to move along the first groove and drive the slider to slide on the connecting rod, so that the moving trajectory of the visual inspection device is a spiral trajectory; a supporting platform is used to carry a silicon wafer to be tested, and the silicon wafer to be tested faces away from the field of view of the visual inspection device, thereby simplifying the structure of the spiral scanning device and ensuring the inspection accuracy at the same time.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of semiconductor technology, and in particular to a silicon wafer backside inspection device and a backside inspection method. Background Art

[0002] The backside inspection of silicon wafers has received more and more attention. At present, the existing scheme is to scan the backside of silicon wafers line by line (such as Figure 1 As shown), circle-by-circle step scanning (as shown Figure 2 as shown) or spiral scanning (as shown Figure 3 The existing scheme has the following problems: 1) Linear scanning covers a small area per line, and the reciprocating motion efficiency is low. Switching between lines will make the entire scanning process discontinuous, affecting efficiency; 2) The stepping scanning method is simpler than line scanning, but it still makes the scanning process discontinuous, affecting efficiency; 3) Spiral scanning can make the scanning process continuous and improve the efficiency of motion detection, but the existing methods are relatively complex to implement, requiring multi-axis coordination to achieve spiral motion, and requiring high coordination of the motion of each axis. Summary of the invention

[0003] The present invention provides a silicon wafer backside inspection device and a backside inspection method, which can simplify the structure of the spiral scanning device and ensure the inspection accuracy at the same time.

[0004] To achieve the above-mentioned purpose, the first embodiment of the present invention provides a silicon wafer back inspection device, including: a spiral guide seat, a connecting rod and a slider;

[0005] The spiral guide rail seat is provided with a first groove arranged spirally from the center to the edge, one end of the connecting rod is connected to the center of the spiral guide rail seat through a rotating shaft, and the other end of the connecting rod performs a circular motion around the center of the spiral guide rail seat, the slider is sleeved on the connecting rod, a first roller is provided on a side of the slider adjacent to the first groove, and a visual detection device is arranged on a side away from the first groove, and the first roller is at least partially provided in the first groove;

[0006] a driving device, the driving device being connected to the rotating shaft and used for driving the connecting rod to rotate, so as to drive the first roller to move along the first groove, and at the same time drive the slider to slide on the connecting rod, so that the moving track of the visual inspection device is a spiral track;

[0007] The carrying platform is used to carry the silicon wafer to be tested, and the silicon wafer to be tested faces the field of view direction of the visual inspection device.

[0008] According to one embodiment of the present invention, the silicon wafer back-inspection equipment also includes: a second roller, the second roller is connected to the other end of the connecting rod, the second roller rolls around the first rolling axis and contacts the outer wall of the spiral guide rail seat, the first rolling axis is arranged parallel to the central axis of the spiral guide rail seat, and the first rolling axis makes a circular motion with the center of the spiral guide rail seat as the center.

[0009] According to one embodiment of the present invention, the silicon wafer back inspection device further includes: a second roller, the second roller is connected to the other end of the connecting rod, the second roller rolls around a second rolling axis, and the second rolling axis is arranged along the radial direction of the trajectory of the other end of the connecting rod making a circular motion;

[0010] The outer edge of the spiral guide rail seat is provided with a circular second groove, and the second roller contacts the groove bottom of the second groove and rolls.

[0011] According to an embodiment of the present invention, the pitch of the first groove of the thread arrangement on the spiral guide rail seat is less than or equal to the field of view distance of the visual inspection device along the pitch direction.

[0012] According to one embodiment of the present invention, the visual detection device is a CCD camera or a CMOS camera.

[0013] To achieve the above-mentioned purpose, the second embodiment of the present invention further proposes a silicon wafer back inspection method, which is implemented based on the silicon wafer back inspection device as described above and includes the following steps:

[0014] Obtaining the trajectory curve equation of the center of the visual inspection device by data fitting;

[0015] Acquire any image collected by the visual inspection device;

[0016] Identify a first position of a defect in the image in a coordinate system of the visual inspection device;

[0017] According to the trajectory curve equation, obtaining a second position of the center of the visual detection device relative to the rotation center of the connecting rod;

[0018] Acquire a third position of the center of the supporting platform relative to the rotation center of the connecting rod;

[0019] Acquire a fourth position of the center of the silicon wafer to be tested relative to the center of the carrier platform;

[0020] The position of the defect relative to the center of the silicon wafer to be tested is obtained according to the first position, the second position, the third position and the fourth position.

[0021] According to one embodiment of the present invention, the trajectory curve equation satisfies the following formula:

[0022]

[0023] Wherein r represents the distance between the point on the trajectory curve and the line connecting the rotation center of the connecting rod, r0 represents the distance from the edge of the spiral guide seat to the rotation center of the connecting rod, θ represents the angle of rotation of the connecting rod, Δd represents the pitch of the first groove, c0, c1, c2 represent the error term coefficient, (x, y) represents the position coordinates of the point on the trajectory curve in the rectangular coordinate system, and the rectangular coordinate system is defined as: the rotation center of the connecting rod is the origin, the line connecting the starting point and the end point of the first groove is the X-axis, and the Y-axis is perpendicular to the X-axis, wherein the rotation center of the connecting rod coincides with the starting point of the first groove.

[0024] According to one embodiment of the present invention, the error term coefficients c0, c1, c2 satisfy:

[0025]

[0026] Among them, θ i represents the rotation angle of the connecting rod theoretically corresponding to the ith mark, (x i ,y i ) represents the actual position where the ith mark is aligned, and a plurality of the marks are evenly distributed on the reference silicon wafer.

[0027] According to one embodiment of the present invention, obtaining a third position of the center of the supporting platform relative to the rotation center of the connecting rod comprises:

[0028] The distance between the center of the support platform and the rotation center of the connecting rod is measured by a measuring instrument, and the third position of the center of the support platform relative to the rotation center of the connecting rod is obtained according to the distance.

[0029] According to an embodiment of the present invention, obtaining a fourth position of the center of the silicon wafer to be tested relative to the center of the carrier platform includes:

[0030] Acquire the outermost circle image of the silicon wafer to be tested;

[0031] Fitting the center of the circle according to the positions of more than three edge points on the outermost circle image;

[0032] Obtaining a deflection angle of a silicon wafer notch in the silicon wafer to be tested relative to a silicon wafer notch in a reference silicon wafer;

[0033] A fourth position of the center of the silicon wafer to be tested relative to the center of the supporting platform is obtained according to the fitting circle center and the deflection angle.

[0034] According to the silicon wafer back-inspection equipment and back-inspection method proposed in the embodiment of the present invention, the equipment includes: a spiral guide seat, a connecting rod and a slider; a first groove arranged spirally from the center to the edge is provided on the spiral guide seat, one end of the connecting rod is connected to the center of the spiral guide seat through a rotating shaft, and the other end of the connecting rod makes a circular motion around the center of the spiral guide seat, and the slider is sleeved on the connecting rod, and a first roller is provided on the side of the slider adjacent to the first groove, and a visual detection device is arranged on the side away from the first groove, and the first roller is at least partially provided in the first groove; a driving device, the driving device is connected to the rotating shaft, and is used to drive the connecting rod to rotate, so as to drive the first roller to move along the first groove, and at the same time drive the slider to slide on the connecting rod, so that the moving trajectory of the visual detection device is a spiral trajectory; a supporting platform, used to carry the silicon wafer to be tested, and the silicon wafer to be tested faces the field of view direction of the visual detection device, so that the detection accuracy can be guaranteed on the basis of simplifying the structure of the spiral scanning equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a scanning track in the prior art;

[0036] Figure 2 It is another scanning track in the prior art;

[0037] Figure 3 It is another scanning trajectory in the prior art;

[0038] Figure 4 It is a structural schematic diagram of a silicon wafer backside inspection device proposed in an embodiment of the present invention;

[0039] Figure 5 It is a schematic diagram of the structure of a spiral guide rail seat in a silicon wafer back inspection device proposed in an embodiment of the present invention;

[0040] Figure 6 is a top view of a spiral guide rail seat in a silicon wafer backside inspection device provided in an embodiment of the present invention;

[0041] Figure 7 yes Figure 6 Cross-sectional view along AA direction;

[0042] Figure 8 It is a top view of a spiral guide rail seat in a silicon wafer back inspection device provided by one embodiment of the present invention;

[0043] Fig. 9 It is a schematic diagram of the pitch of the spiral guide rail seat in the silicon wafer back inspection device proposed in an embodiment of the present invention;

[0044] Fig.10 is a flow chart of a silicon wafer back inspection method proposed in an embodiment of the present invention;

[0045] Fig.11It is a coordinate schematic diagram of obtaining a trajectory curve equation in a silicon wafer back inspection method provided in an embodiment of the present invention;

[0046] Fig.12 1 is a schematic structural diagram of a reference silicon wafer in a silicon wafer back inspection method provided in an embodiment of the present invention;

[0047] Fig.13 Schematic diagram of the spiral scanning path planning of the silicon wafer back inspection method proposed in the embodiment of the present invention;

[0048] Fig.14 It is a schematic diagram of determining defect positions in a silicon wafer backside inspection method proposed in an embodiment of the present invention. DETAILED DESCRIPTION

[0049] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0050] Figure 4 Schematic diagram of the structure of the silicon wafer back inspection device proposed in the embodiment of the present invention. Figures 4 to 7 As shown, the silicon wafer back inspection device 100 includes: a spiral guide rail seat 101, a connecting rod 102, a slider 103, a driving device 104 and a carrier 105;

[0051] The spiral guide seat 101 is provided with a first groove 106 which is arranged spirally from the center to the edge, one end of the connecting rod 102 is connected to the center of the spiral guide seat 101 through a rotating shaft 111, and the other end of the connecting rod 102 makes a circular motion around the center of the spiral guide seat 101, and the slider 103 is sleeved on the connecting rod 102, and a first roller 107 is provided on the side of the slider 103 adjacent to the first groove 106, and a visual inspection device 108 is arranged on the side away from the first groove 106, and the first roller 107 is at least partially arranged in the first groove 106; the driving device 104 is connected to the rotating shaft 111, and is used to drive the connecting rod 102 to rotate, so as to drive the first roller 107 to move along the first groove 106, and at the same time drive the slider 103 to slide on the connecting rod 102, so that the moving trajectory of the visual inspection device 108 is a spiral trajectory; the supporting platform 105 is used to carry the silicon wafer 109 to be tested, and the silicon wafer 109 to be tested faces the field of view of the visual inspection device 108.

[0052] It should be noted that the driving device 104 may be a driving motor or other driving devices in the art that can realize the rotation of the connecting rod 102, and the present invention does not impose any specific limitation on this. The supporting platform 105 may be an inverted platform bracket (such as Figure 4As shown), the platform bracket has three bracket claws, and the edge endpoints of each bracket claw form a circle. The three bracket claws are used to grasp the edge of the silicon wafer 109 to be tested to fix the silicon wafer 109 to be tested. During the detection process, the supporting platform 105 remains stationary, and the center of the supporting platform 105 tries to coincide with the rotation center of the connecting rod 102.

[0053] It is understandable that one end of the connecting rod 102 with the rotating shaft 111 is located at the starting end of the first groove 106 and coincides with the center of the spiral guide seat 101. The spiral guide seat 101 is a disc, the first groove 106 is a spiral groove cut in the disc, and the first roller 107 rolls against the bottom of the spiral groove.

[0054] Based on this, the driving device 104 drives the rotating shaft 111 to drive the connecting rod 102 to rotate, so that the first roller 107 arranged on the side of the slider 103 on the connecting rod 102 adjacent to the first groove 106 rolls in the first groove 106 to drive the slider 103 to slide on the connecting rod 102, and then the moving trajectory of the visual inspection device 108 arranged on the side of the slider 103 away from the first groove 106 is a spiral trajectory, so that the spiral scanning faces the silicon wafer 109 to be tested that is arranged in the field of view direction of the visual inspection device 108. The silicon wafer inspection equipment 100 can drive the connecting rod 102 to rotate only by the rotating shaft 111 and the driving device 104 arranged at one end of the connecting rod 102, and combined with the spiral guide seat 101, the spiral scanning of the silicon wafer 109 to be tested by the visual inspection device 108 can be completed, that is, the single rotational motion is converted into a spiral motion through the spiral guide seat 101 and the slider 103, which reduces the complexity of the equipment, reduces the difficulty of realizing spiral scanning detection, and improves the detection efficiency.

[0055] According to one embodiment of the present invention, Figure 4 As shown, the silicon wafer back-inspection equipment 100 also includes: a second roller 110, the second roller 110 is connected to the other end of the connecting rod 102, the second roller 110 rolls around the first rolling axis 113 and contacts the outer wall of the spiral guide seat 101, the first rolling axis 113 is arranged parallel to the central axis of the spiral guide seat 101, and the first rolling axis 113 makes a circular motion with the center of the spiral guide seat 101 as the center.

[0056] In this embodiment, when one end of the connecting rod 102 rotates at the center of the spiral guide rail seat 101, the second roller 110 is provided at the other end of the connecting rod 102 to improve the stability of the connecting rod 102, and prevent the connecting rod 102 from shaking, which causes the visual inspection device 108 to collect inaccurate images of the silicon wafer 109 to be inspected, so that the second roller 110 is provided to help improve the accuracy of the inspection. The second roller 110 in this embodiment rolls against the outer wall of the spiral guide rail seat 101, and the friction between the outer wall of the spiral guide rail seat 101 and the second roller 110 can keep the connecting rod 102 stable. In addition, the structural design of the spiral guide rail seat 101 is simplified.

[0057] According to one embodiment of the present invention, Figure 8 As shown, the silicon wafer back inspection device 100 further includes: a second roller 110, the second roller 110 is connected to the other end of the connecting rod 102, the second roller 110 rolls around a second rolling axis, and the second rolling axis (not shown in the figure) is arranged along the radial direction of the trajectory of the other end of the connecting rod 102 making a circular motion;

[0058] A circular second groove 112 is provided on the outer edge of the spiral guide rail seat 101 , and the second roller 110 rolls in contact with the bottom of the second groove 112 .

[0059] Similarly, in this embodiment, when one end of the connecting rod 102 rotates at the center of the spiral guide seat 101, the second roller 110 is arranged at the other end of the connecting rod 102 to improve the stability of the connecting rod 102 and prevent the connecting rod 102 from shaking, which causes the visual inspection device 108 to capture inaccurate images of the silicon wafer 109 to be tested. The arrangement of the second roller 110 is thereby helpful in improving the accuracy of the inspection.

[0060] According to one embodiment of the present invention, Fig. 9 As shown, the pitch d1 of the first groove 106 of the thread arrangement on the spiral guide rail seat 101 is less than or equal to the field of view distance d2 of the visual detection device 108 along the pitch direction.

[0061] That is to say, when the visual inspection device 108 spirally scans the silicon wafer 109 to be tested, the effective field of view of the visual inspection device 108 along the pitch direction must cover the pitch range, so that no position on the silicon wafer 109 to be tested will be missed. When the pitch d1 is equal to the field of view distance d2 of the visual inspection device 108 along the pitch direction, the visual inspection device 108 can just detect no position on the silicon wafer 109 to be tested, and the image acquisition of the silicon wafer 109 to be tested between adjacent pitches will not be repeated, reducing the difficulty of subsequent image processing.

[0062] According to one embodiment of the present invention, the visual detection device 108 is a CCD camera or a CMOS camera.

[0063] In the above-mentioned silicon wafer back inspection device 100, although the center of the support platform 105, the center of the silicon wafer to be tested 109, and the rotation center of the connecting rod 102 are made to coincide as much as possible, there will always be an offset between the above center points in actual operation, resulting in inaccurate detection by the visual inspection device 108 (the position of the defect will always be offset relative to the position of the center of the silicon wafer to be tested). Therefore, the embodiment of the present invention proposes a silicon wafer back inspection method to make corrections so that the detection result is more accurate (the position of the defect relative to the position of the center of the silicon wafer to be tested is the actual position of the defect on the silicon wafer to be tested). The silicon wafer back inspection method proposed in the embodiment of the present invention is described in detail below.

[0064] Fig.10 1 is a flow chart of a silicon wafer back inspection method proposed in an embodiment of the present invention. The method is implemented based on the silicon wafer back inspection device as described above. Fig.10 As shown, the method comprises the following steps:

[0065] S101, obtaining a trajectory curve equation of the center of the visual inspection device by data fitting;

[0066] According to one embodiment of the present invention, the trajectory curve equation satisfies the following formula:

[0067]

[0068] Among them, Fig.11 As shown, r represents the distance between the point on the trajectory curve and the line connecting the rotation center of the connecting rod, r0 represents the distance from the edge of the spiral guide seat to the rotation center of the connecting rod, θ represents the angle of rotation of the connecting rod, Δd represents the pitch of the first groove, c0, c1, c2 represent the error term coefficient, (x, y) represents the position coordinates of the point on the trajectory curve in the rectangular coordinate system, and the rectangular coordinate system is defined as: the rotation center of the connecting rod is the origin, the line connecting the starting point and the end point of the first groove is the X-axis, and the Y-axis is perpendicular to the X-axis, wherein the rotation center of the connecting rod coincides with the starting point of the first groove.

[0069] According to one embodiment of the present invention, the error term coefficients c0, c1, c2 satisfy:

[0070]

[0071] Among them, θ i represents the rotation angle of the connecting rod theoretically corresponding to the ith mark, (x i ,y i ) represents the actual position of the ith mark aligned, and multiple marks are evenly distributed on the reference silicon wafer.

[0072] It should be noted that if Fig.12As shown, the spiral trajectory curve equation is obtained by detecting the reference silicon wafer. First, multiple marks (such as the "+" mark in the figure) are marked on the reference silicon wafer. The multiple marks are evenly distributed on the reference silicon wafer. The positions of these marks marked in advance are marked relative to the center of the reference silicon wafer, that is, the rotation angle of the connecting rod corresponding to each mark on the reference silicon wafer can be marked. Among them, the multiple marks are at least three.

[0073] Next, after marking multiple marks, the reference silicon wafer is placed on the silicon wafer back-inspection equipment, and the positions of multiple actual points of the reference silicon wafer are spirally collected by the visual inspection device. The spiral trajectory curve equation can be fitted according to multiple sets of actual result data. Then, the error term coefficient can be calculated according to the actual result data and theoretical data of multiple marked points, so that the spiral trajectory curve equation finally obtained is the trajectory curve equation that carries the error between the actual spiral trajectory and the reference spiral trajectory. Therefore, since the center of the visual inspection device is the spiral trajectory, the spiral trajectory curve equation can be the trajectory curve equation of the center of the visual inspection device, and the center point of each image collected by the visual inspection device is on the trajectory.

[0074] Since the center point of each image captured by the visual detection device is at the center of the field of view of the visual detection device, the position of any other point in the image relative to the position of the center of the field of view can be obtained. Since the position of the center of the field of view relative to the rotation center of the connecting rod can be obtained through the spiral trajectory curve equation, the position of any other point in the image relative to the position of the rotation center of the connecting rod can be obtained.

[0075] S102, obtaining any image collected by the visual detection device;

[0076] S103, identifying a first position of a defect in the image in a coordinate system of a visual inspection device;

[0077] S104, obtaining a second position of the center of the visual inspection device relative to the rotation center of the connecting rod according to the trajectory curve equation;

[0078] It should be noted that step S101 is obtained by detecting the reference silicon wafer. After step S102, the reference silicon wafer needs to be replaced with the silicon wafer to be tested. After replacing the silicon wafer to be tested, the photographing positions are planned in sequence according to the rotation angle (such as Fig.13 As shown in the figure, the planning principle is that the camera can evenly cover the entire silicon wafer while taking the least number of photos. The visual inspection device collects an image of a certain position on the silicon wafer to be tested, and can identify the defect in the image through the image recognition algorithm, and know the first position of the defect in the coordinate system of the visual inspection device, and according to the trajectory curve equation, the position of the defect relative to the rotation center of the connecting rod can be known, thereby transferring the defect position in the image to the coordinate system where the spiral guide seat is located.

[0079] S105, obtaining a third position of the center of the bearing platform relative to the rotation center of the connecting rod;

[0080] According to one embodiment of the present invention, obtaining a third position of the center of the support platform relative to the rotation center of the connecting rod includes:

[0081] The distance between the center of the bearing platform and the rotation center of the connecting rod is measured by a measuring instrument, and the third position of the center of the bearing platform relative to the rotation center of the connecting rod is obtained according to the distance.

[0082] Theoretically, the center of the support platform coincides with the rotation center of the connecting rod. However, due to equipment assembly problems, the center of the support platform and the rotation center of the connecting rod may not coincide, and correction is required.

[0083] When assembling the equipment, the distance between the center of the support platform and the rotation center of the connecting rod can be measured by a measuring instrument (such as a laser ruler or interferometer or other distance measuring tools), so that the position coordinates of the rotation center of the connecting rod can be transferred to the coordinate system of the support platform, and then the position of the defect can be transferred to the coordinate system of the support platform.

[0084] S106, obtaining a fourth position of the center of the silicon wafer to be tested relative to the center of the carrier platform;

[0085] According to one embodiment of the present invention, obtaining a fourth position of the center of the silicon wafer to be tested relative to the center of the carrier platform includes:

[0086] Acquire the outermost circle image of the silicon wafer to be tested;

[0087] Fit the center of the circle according to the positions of more than three edge points on the outermost circle image;

[0088] Obtaining a deflection angle of a silicon wafer notch in the silicon wafer to be tested relative to a silicon wafer notch in a reference silicon wafer;

[0089] A fourth position of the center of the silicon wafer to be measured relative to the center of the supporting platform is obtained according to the fitting circle center and the deflection angle.

[0090] It should be noted that the center of the silicon wafer to be tested should theoretically coincide with the center of the carrier platform, but since the silicon wafer to be tested may not be placed correctly each time, the center of the silicon wafer to be tested cannot coincide with the center of the carrier platform, and thus, correction is required. First, the fitting center of the silicon wafer to be tested is obtained, and then the distance between the fitting center and the center of the carrier platform is obtained. In addition, when placing the silicon wafer to be tested, it is also possible to have a deflection angle of the silicon wafer to be tested relative to the reference silicon wafer, so that the rotation angle of the positioning coordinate system on the silicon wafer to be tested relative to the positioning coordinate system of the reference silicon wafer is obtained through the deflection angle of the silicon wafer notch on the silicon wafer to be tested and the silicon wafer notch of the reference silicon wafer. Thus, based on the distance and deflection angle between the fitting center and the center of the carrier platform, the center position of the carrier platform can be transferred to the coordinate system of the silicon wafer to be tested, and then the position of the defect can be transferred to the coordinate system of the silicon wafer to be tested.

[0091] S107, obtaining a position of the defect relative to the center of the silicon wafer to be tested according to the first position, the second position, the third position and the fourth position.

[0092] Specifically, if Fig.14 As shown, take pictures circle by circle along the planned path, use the image recognition algorithm to calculate the pixel position of the defect in the picture, and convert it to obtain the physical position Pospycs of the defect relative to the camera center O2.

[0093] The position V2 of the actual camera center relative to the rotation center O1 of the connecting rod is calculated based on the spiral trajectory curve equation from the rotation angle corresponding to the picture. The rotation center O1 of the connecting rod is stationary relative to the center O3 of the supporting platform, and the position relationship is V1. Therefore, the position of the defect relative to the supporting platform Pospycs+V1+V2 can be obtained.

[0094] By identifying the photo of the outermost circle of the silicon wafer, the center of the circle O4 is fitted from the positions of more than three edge points to obtain the offset error of the center O4 of the silicon wafer to be tested relative to the supporting platform. At the same time, the rotation angle of the Notch (silicon wafer notch) relative to the ideal wafer loading position (without error) is found to obtain the deviation error of the silicon wafer to be tested, thereby obtaining the relationship V0 of the silicon wafer to be tested relative to the supporting platform.

[0095] Then, the position relationship of the defect relative to the center O4 of the silicon wafer to be tested can be calculated, so as to achieve the purpose of online error correction and obtain the accurate position of the defect on the back side of the silicon wafer to be tested. The calculation formula is: Posgwcs=Pospycs+V0+V1+V2.

[0096] Therefore, by designing a spiral guide structure, the trajectory control of the spiral motion is guaranteed by pure mechanism motion relationship, reducing the difficulty of control. At the same time, in order to avoid errors introduced by mechanical equipment manufacturing and assembly, a combination of offline calibration and online correction is used to ensure detection accuracy, thus achieving the goal of high-precision spiral motion detection by controlling a single rotating axis.

[0097] In summary, according to the silicon wafer back-inspection equipment and back-inspection method proposed in the embodiments of the present invention, the equipment includes: a spiral guide seat, a connecting rod and a slider; a first groove arranged spirally from the center to the edge is provided on the spiral guide seat, one end of the connecting rod is connected to the center of the spiral guide seat through a rotating shaft, and the other end of the connecting rod makes a circular motion around the center of the spiral guide seat, and the slider is sleeved on the connecting rod, and a first roller is provided on the side of the slider adjacent to the first groove, and a visual inspection device is arranged on the side away from the first groove, and the first roller is at least partially provided in the first groove; a driving device, the driving device is connected to the rotating shaft, and is used to drive the connecting rod to rotate, so as to drive the first roller to move along the first groove, and at the same time drive the slider to slide on the connecting rod, so that the moving trajectory of the visual inspection device is a spiral trajectory; a supporting platform, used to carry the silicon wafer to be tested, and the silicon wafer to be tested is facing away from the field of view of the visual inspection device, so that the detection accuracy can be guaranteed on the basis of simplifying the structure of the spiral scanning equipment.

[0098] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A silicon wafer backside inspection device, characterized in that: include: spiral guide seat, connecting rod and slide block; The spiral guide rail seat is provided with a first groove arranged spirally from the center to the edge, one end of the connecting rod is connected to the center of the spiral guide rail seat through a rotating shaft, and the other end of the connecting rod performs a circular motion around the center of the spiral guide rail seat, the slider is sleeved on the connecting rod, a first roller is provided on a side of the slider adjacent to the first groove, and a visual detection device is arranged on a side away from the first groove, and the first roller is at least partially provided in the first groove; a driving device, the driving device being connected to the rotating shaft and used for driving the connecting rod to rotate, so as to drive the first roller to move along the first groove, and at the same time drive the slider to slide on the connecting rod, so that the moving track of the visual inspection device is a spiral track; The carrying platform is used to carry the silicon wafer to be tested, and the silicon wafer to be tested faces the field of view direction of the visual inspection device.

2. The silicon wafer backside inspection equipment according to claim 1, characterized in that: Also includes: A second roller, the second roller is connected to the other end of the connecting rod, the second roller rolls around the first rolling axis and contacts the outer wall of the spiral guide rail seat, the first rolling axis is arranged parallel to the central axis of the spiral guide rail seat, and the first rolling axis makes a circular motion with the center of the spiral guide rail seat as the center.

3. The silicon wafer back inspection equipment according to claim 1, characterized in that: Also includes: a second roller, the second roller being connected to the other end of the connecting rod, the second roller rolling around a second rolling axis, the second rolling axis being arranged along the radial direction of a trajectory of the other end of the connecting rod making a circular motion; The outer edge of the spiral guide rail seat is provided with a circular second groove, and the second roller contacts the groove bottom of the second groove and rolls.

4. The silicon wafer backside inspection equipment according to claim 1, characterized in that: The pitch of the first groove of the thread arrangement on the spiral guide rail seat is less than or equal to the field of view distance of the visual detection device along the pitch direction.

5. The silicon wafer backside inspection equipment according to claim 1, characterized in that: The visual detection device is a CCD camera or a CMOS camera.

6. A silicon wafer back inspection method, characterized in that: The silicon wafer back inspection device according to any one of claims 1 to 5 is implemented, comprising the following steps: Obtaining the trajectory curve equation of the center of the visual inspection device by data fitting; Acquire any image collected by the visual inspection device; Identifying a first position of a defect in the image in a coordinate system of the visual inspection device; According to the trajectory curve equation, obtaining a second position of the center of the visual detection device relative to the rotation center of the connecting rod; Acquire a third position of the center of the supporting platform relative to the rotation center of the connecting rod; Acquire a fourth position of the center of the silicon wafer to be tested relative to the center of the carrier platform; The position of the defect relative to the center of the silicon wafer to be tested is obtained according to the first position, the second position, the third position and the fourth position.

7. The silicon wafer back inspection method according to claim 6, characterized in that: The trajectory curve equation satisfies the following formula: Wherein r represents the distance between the point on the trajectory curve and the line connecting the rotation center of the connecting rod, r0 represents the distance from the edge of the spiral guide seat to the rotation center of the connecting rod, θ represents the angle of rotation of the connecting rod, Δd represents the pitch of the first groove, c0, c1, c2 represent the error term coefficient, (x, y) represents the position coordinates of the point on the trajectory curve in the rectangular coordinate system, and the rectangular coordinate system is defined as: the rotation center of the connecting rod is the origin, the line connecting the starting point and the end point of the first groove is the X-axis, the Y-axis is perpendicular to the X-axis, and the rotation center of the connecting rod coincides with the starting point of the first groove.

8. The silicon wafer back inspection method according to claim 7, characterized in that: The error term coefficients c0, c1, c2 satisfy: Among them, θ i represents the rotation angle of the connecting rod theoretically corresponding to the ith mark, (x i ,y i ) represents the actual position where the ith mark is aligned, and a plurality of the marks are evenly distributed on the reference silicon wafer.

9. The silicon wafer back inspection method according to claim 6, characterized in that: The obtaining of a third position of the center of the support platform relative to the rotation center of the connecting rod comprises: The distance between the center of the support platform and the rotation center of the connecting rod is measured by a measuring instrument, and the third position of the center of the support platform relative to the rotation center of the connecting rod is obtained according to the distance.

10. The silicon wafer backside inspection method according to claim 6, characterized in that: The step of obtaining a fourth position of the center of the silicon wafer to be tested relative to the center of the carrier platform comprises: Acquire the outermost circle image of the silicon wafer to be tested; Fitting the center of the circle according to the positions of more than three edge points on the outermost circle image; Obtaining a deflection angle of a silicon wafer notch in the silicon wafer to be tested relative to a silicon wafer notch in a reference silicon wafer; A fourth position of the center of the silicon wafer to be tested relative to the center of the supporting platform is obtained according to the fitting circle center and the deflection angle.

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