Wafer edge dynamic trimming method and wafer trimming device

Abstract

The invention provides a wafer edge dynamic trimming method and a wafer trimming device. The method comprises the following steps: placing a wafer on a carrying table; the height of the whole circle of the wafer is detected, and the offset L of the circle center of the wafer on the XY plane relative to the circle center of the carrying table is obtained; edge trimming is carried out, a cutter wheel makes contact with the edge angle of the annular step on the edge of the wafer so as to cut the edge angle into an arc-shaped notch, and it is avoided that colloid protruding points are accumulated on the edge of the annular step when the surface of the wafer is glued; the cutter wheel can move in the X direction and the Z direction, and the cutter wheel makes contact with the wafer at one end of the Y-direction diameter of the wafer; the feed amount of the cutter wheel is set by taking the circle center of the carrying table as a reference and is dynamically compensated based on the offset, the Z-direction compensation amount is a difference value between the whole circle height of the wafer and the circle center of the wafer, and the X-direction compensation amount is L * cos (a); the cutter wheel performs additional swing motion in the X direction to homogenize abrasion of the cutter wheel, and the additional swing range is smaller than the width of the cutter wheel. According to the technical scheme, wafer edge trimming is more uniform, and wafer edge breakage is reduced.

Description

Technical Field

[0001] This application relates to the field of semiconductor wafer processing technology, specifically to a method and apparatus for dynamic trimming of wafer edges. Background Technology

[0002] Backside thinning is the process of thinning the back side of a wafer. This process is mainly completed through three steps: rough grinding, fine grinding, and polishing. During thinning, the wafer edges are prone to chipping as the wafer becomes thinner. Edge trimming is typically used to create annular steps at the wafer edges to reduce chipping. However, after edge trimming, the annular steps are right-angled. During subsequent coating processes, due to surface tension at the edges, the coating solution thickens, forming coating adhesive bumps that remain after etching. These coating residues can cause wafer chipping and exposed copper in the next process, resulting in surface defects and metal contamination. Therefore, it is necessary to treat the adhesive bumps at the edges of the annular steps.

[0003] In addition, when trimming the edge of the wafer, the wafer cannot be perfectly aligned with the center of the stage, resulting in low trimming accuracy, uneven stress on the wafer edge, and easy stress concentration. Summary of the Invention

[0004] This application provides a method and apparatus for dynamic trimming of wafer edges to solve or alleviate at least some of the problems mentioned above.

[0005] According to one aspect of this application, a method for dynamic trimming of wafer edges is provided, characterized in that it includes: Place the wafer on the stage; Detect the height of the entire wafer circumference and obtain the offset L of the wafer center relative to the stage center on the XY plane; Edge trimming is performed by contacting the edge of the annular step on the wafer edge with the cutter wheel to cut it into an arc-shaped notch, so as to avoid the accumulation of adhesive bumps at the edge of the annular step when applying adhesive to the wafer surface; the cutter wheel can move along the X and Z directions and contacts the wafer at one end of the Y-direction diameter; The feed rate of the cutter wheel is set based on the center of the stage and dynamically compensated based on the offset. The X-axis compensation is L*cos(a), where a is the stage rotation angle. The cutter wheel has an additional oscillating motion in the X-axis to even out the wear of the cutter wheel. The additional oscillation range is smaller than the width of the cutter wheel.

[0006] Optionally, during edge trimming, the Z-axis compensation of the cutter wheel is the difference between the wafer's full circumference height and the center of the wafer's upper surface.

[0007] Optionally, during edge trimming, the stage and the cutter wheel are linked to compensate for the offset, and the Y-axis linkage compensation of the stage is L*sin(a).

[0008] Optionally, during edge trimming, the cutter wheel is fed in stages: Phase 1: The cutter wheel cuts into the wafer at the first feed ratio; Second stage: The cutter wheel cuts the wafer at the second feed ratio; Third stage: The cutter wheel cuts the wafer at the third feed ratio; The feed ratio is the ratio of the depth to the width of the edge of the annular step cut by the tool wheel. The first feed ratio is smaller than the second feed ratio to avoid damage to the wafer edge by the cutting impact force. The third feed ratio is smaller than the second feed ratio to smooth the edge between the upper surface of the wafer and the arc notch. The profile formed in the third stage covers the profile formed in the first two stages.

[0009] Optionally, the total cutting depth of the cutter wheel is greater than the depth of the annular step and less than the total thickness of the wafer, so as to trim the outermost edge of the wafer.

[0010] Optionally, when the offset is greater than the offset threshold, the wafer is moved and repositioned on the stage using the robot arm of the wafer edge trimming device, and the step of obtaining the offset is repeated until the offset is less than the offset threshold before edge trimming is performed.

[0011] Optionally, the method further includes: after processing a preset number of wafers, using a test wafer to detect the current diameter of the cutting wheel to determine the wear amount of the cutting wheel, and adjusting the feed amount of the cutting wheel based on the wear amount; wherein, the length of the cut formed by the cutting wheel when cutting a preset depth on the test wafer is detected, and the current diameter of the cutting wheel is determined based on the preset depth and the length of the cut.

[0012] Optionally, the steps for determining the wafer center are as follows: pick four points on the edge of the wafer, and take three of these points to find the center of the wafer, resulting in four centers. Then, arbitrarily select three of these four centers to determine the wafer center.

[0013] According to another aspect of this application, a wafer edge trimming apparatus is provided for the aforementioned dynamic wafer edge trimming method, comprising: The stage can slide along the longitudinal track and is used to horizontally support the wafer and drive the wafer to rotate; The trimming assembly is mounted on the crossbeam by a moving assembly and moves laterally and vertically by the moving assembly. The trimming assembly includes a cutting wheel for cutting the edge of the wafer. Inspection facilities are used to inspect wafers before trimming.

[0014] According to another aspect of this application, a wafer edge trimming apparatus is provided for the aforementioned dynamic wafer edge trimming method, comprising: The detection module is used to detect the height of the wafer edge and the offset of the wafer center; The control module is used to control the movement of the cutter wheel and / or the stage based on the detection results of the detection module; The execution module, including the tool wheel and stage, is used to execute the instructions of the control module to perform dynamic trimming of the wafer edges.

[0015] According to the wafer edge dynamic trimming method and wafer trimming apparatus of this application, by setting the compensation amount of the cutting wheel based on the offset of the wafer center, the offset of the wafer relative to the stage in the X direction can be offset, making the trimming of the wafer edge by the cutting wheel closer to the desired trimming shape, and making the wafer more uniformly stressed during cutting, reducing edge damage and stress concentration, improving the edge trimming quality of the wafer, and thus improving the quality and yield of 3D stacked chips. The additional oscillation of the cutting wheel allows the abrasive grains on the cutting wheel to work intermittently, greatly improving the heat dissipation conditions of individual abrasive grains, avoiding local overheating, and the wear is evenly distributed across the axial width of the cutting wheel, significantly delaying the shape distortion of specific areas of the cutting wheel, so that the cutting wheel can maintain stable cutting performance and contour accuracy for a longer period of time. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings.

[0017] Figure 1 A side view diagram for wafer dicing; Figure 2 This is a side view of a wafer coated with colloid after edge trimming. Figure 3 A side view diagram for wafer angle trimming; Figure 4 A schematic diagram of a wafer trimming device; Figure 5 for Figure 4 A top view of the wafer trimming device in the middle; Figure 6 A flowchart illustrating a method for dynamic trimming of wafer edges according to one embodiment of this application is shown. Figure 7 This is a schematic diagram showing the overall offset of the wafer center relative to the stage center as the wafer rotates with the stage; Figure 8 Show Figure 7 Top view; Figure 9 A schematic diagram showing the contact state between the cutting wheel and the wafer is provided. Figure 10 This diagram illustrates the staged feeding of the cutter wheel. Figure 11 A schematic diagram showing a wafer trimming apparatus according to another embodiment of this application is shown; Figure 12 Show Figure 11 A schematic diagram of the wafer trimming device from another angle; Figure 13 Show Figure 11 A top view of the wafer trimming device. Detailed Implementation

[0018] To enable those skilled in the art to better understand the technical solutions in the embodiments of this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art should fall within the protection scope of the embodiments of this application.

[0019] In the description of this application, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0020] In addition, in the description of this application, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, or internal connections between two components. They can be direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0021] like Figure 1 This is a schematic diagram of wafer edge trimming. The cutting wheel 61 forms a right-angled step-shaped cut at the edge of the wafer. During trimming, the wafer rotates around its axis, thus forming a ring-shaped step along the outer periphery of the wafer. In the manufacturing process of three-dimensional stacked chips, after the edge trimming process, such as... Figure 2 This requires a photoresist coating process, such as... Figure 2The image shows a colloidal coating in gray. Due to the surface tension of the colloid, the coating will accumulate and thicken at the edge of the wafer, creating colloidal bumps. These bumps will remain after subsequent etching processes. The residual colloid will cause wafer edge chipping, which will also lead to metal exposure, such as exposed copper. This will seriously affect the wafer processing quality, yield, and the performance of the formed three-dimensional stacked chip.

[0022] To remove these colloidal bumps, this application provides an angle trimming method, such as... Figure 3 As shown, the cutter wheel 61 contacts the corner of the annular step to cut the corner of the annular step into an arc-shaped notch and remove the adhesive protrusions accumulated at the corner during adhesive application. Figure 1 , Figure 3 The hollow arrow in the diagram indicates a schematic direction of rotation.

[0023] like Figure 4 A schematic diagram of a wafer trimming apparatus 100 according to this application is shown. The apparatus includes a frame, a crossbeam 10, two columns 20 supported at both ends of the crossbeam 10, and a longitudinal track 30 located below the crossbeam 10. For example, the crossbeam 10 extends along the X-axis, the longitudinal track 30 along the Y-axis, and the columns 20 along the Z-axis. The longitudinal track 30 can be mounted on a base 40, which is fixedly connected to the columns 20. A sliding platform 50 is provided on the longitudinal track 30. The upper surface of the platform 50 is parallel to the XY plane and is used to horizontally support the wafer. It is driven by a motor 51 below to rotate around its axis, causing the wafer to rotate with it; for example, a DD motor 51 (Direct Drive Motor). The wafer trimming apparatus 100 also includes a trimming assembly 60 suspended from the crossbeam 10, which can move laterally (X-axis) and vertically (Z-axis). The two trimming assemblies 60 include opposing cutter wheels 61, both of which have axes extending in the X direction. The cutter wheels 61 are driven by a main shaft 62 extending in the X direction to rotate about their axes. During angle trimming, combined with... Figure 4 and Figure 5 shown Figure 4 As can be seen from the top view, the stage 50 moves along the longitudinal track 30 to the longitudinal position of the wafer's Y-axis diameter (i.e., the diameter extending along the Y-axis) where the cutter wheel 61 is located. One of the two cutter wheels 61 moves in the X-axis to the wafer's Y-axis diameter, and then the cutter wheel 61 descends to contact the edge of the wafer's annular step and perform angle trimming.

[0024] For example Figure 4 The wafer trimming device also includes a detection mechanism 70 that is fixedly connected to the spindle 62 of the blade wheel 61 via a mounting base, for detecting the alignment of the wafer with the center of the stage 50 and the height of the wafer surface.

[0025] Normally, the alignment between the wafer center and the stage 50 center can be checked by a testing mechanism. If misalignment exists, the wafer is repositioned to adjust its position. However, since the wafer is vacuum-adhered and fixed by the stage 50's suction plate after being placed on it, releasing the suction and lifting the wafer again increases equipment energy consumption. On the other hand, after the wafer is lifted and repositioned by the robot arm that moves or transports the wafer, due to the robot arm's operational error, there will still be some misalignment between the wafer and the stage 50, and perfect alignment cannot be guaranteed. In addition, the wafer itself may have thickness differences, that is, after it is placed on the stage 50, the entire outer edge may have different heights. If the cutter wheel 61 always feeds with the same Z-axis feed amount, it will result in different Z-axis dimensions of the arc-shaped notch formed on the entire outer circumference of the wafer, increasing the stress unevenness at the wafer edge. Therefore, this application provides a method for dynamic trimming of wafer edges to compensate for the offset between the wafer and the stage 50 in the horizontal plane and the non-uniformity of the wafer's outer periphery in the Z direction by dynamically moving the cutter wheel 61 and / or the stage 50 during the processing. Figure 6 As shown in the flowchart, the dynamic trimming method for wafer edges can specifically include: S1: Place the wafer on stage 50; S2: Detect the height of the entire wafer circumference and obtain the offset L of the wafer center relative to the center of stage 50 on the XY plane; S3: Perform edge trimming. The outer peripheral surface of the cutter wheel 61 contacts the edge of the annular step of the wafer to cut it into an arc-shaped notch, so as to avoid the accumulation of adhesive bumps at the edge of the annular step when applying adhesive to the wafer surface. The cutter wheel 61 can move along the X and Z directions and the cutter wheel 61 contacts the wafer at one end of the Y diameter of the wafer. S4: The feed rate of the cutter wheel 61 is based on the center of the stage 50 and dynamically compensated based on the offset. The X-axis compensation is L*cos(a), where a is the rotation angle of the stage 50. The cutter wheel 61 adds an oscillating motion in the X-axis to even out the wear of the cutter wheel 61. The additional oscillation range is smaller than the width of the cutter wheel 61.

[0026] In a preferred embodiment, step S4 may include: the Z-axis compensation amount of the grinding wheel is the difference between the wafer's full circumference height and the center of the wafer's upper surface. Step S4 may also include: during edge trimming, the stage 50 and the tool wheel 61 are linked to compensate for the offset L, and the Y-axis linkage compensation amount of the stage 50 is L*sin(a).

[0027] like Figure 7This diagram illustrates the overall offset of the wafer's center (specifically, the center of the wafer's upper surface) relative to the center of stage 50 as the wafer rotates with stage 50. For simplicity, the annular step is not shown in the diagram. O1 represents the center of stage 50, O2 represents the center of the upper surface of the wafer (shown in blue), and after stage 50 rotates by an angle 'a', the blue wafer rotates to the position of the wafer shown in red. O3 represents the center of the upper surface of the red wafer. It can be understood that in the Z-axis, the wafer's center relative to the center of stage 50 does not change with the rotation of stage 50. Figure 8 Show Figure 7 The top view shows the projections of O2 and O3 onto the XY plane, respectively, and L is the offset between the wafer center and the stage 50 center on the horizontal plane. Taking the measurement with O2' on the X-axis as an example, when the stage 50 rotates by an angle 'a', the component of the offset L in the X-axis is L*cos(a), and the offset in the Y-axis is L*sin(a). Based on this, during the process of the stage 50 driving the wafer to rotate and the cutter wheel 61 feeding to trim the wafer angle, a dynamic compensation amount can be set for the cutter wheel 61 based on its basic feed amount. The basic feed amount of the cutter wheel 61 is based on the center of the stage 50 (i.e., the wafer center and the stage 50 center are precisely aligned by default, but there is actually a deviation) and is set based on the desired arc-shaped notch shape. The dynamic compensation amount is set based on the changes in the components of the offset in the X and Y directions. Figure 4 , Figure 5 In this implementation, the cutting wheel 61 can move along the X-direction, therefore an X-direction compensation amount L*cos(a) is set for it to counteract the offset of the wafer center relative to the center of the stage 50 in the X-direction. This makes the cutting wheel 61 trim the wafer edge closer to the desired trimming shape and makes the wafer more uniformly stressed during cutting, reducing edge damage and stress concentration. In addition, a Z-direction compensation amount is also set for the cutting wheel. The Z-direction compensation amount is the difference between the wafer's circumference height and the wafer center. The Z-direction compensation amount of the cutting wheel ensures that the cutting amount of the cutting wheel in the Z-direction is uniform along the wafer circumference, avoiding stress concentration at the wafer edge caused by uneven depth of the arc notch.

[0028] Furthermore, the stage 50 can be moved to form a dynamic linkage compensation with the cutter wheel 61. The stage 50 can move along the Y direction, and the Y-direction linkage compensation amount of the stage 50 is L*sin(a). Thus, through the dynamic linkage compensation of the cutter wheel 61 in the X direction and the stage 50 in the Y direction, the cutter wheel 61 can dynamically feed with the center of the wafer as the reference during the processing. The basic feed amount of the cutter wheel 61 can be accurately and uniformly delivered to the wafer, rather than having an offset between the center of the wafer and the center of the stage 50. This ensures that the wafer is subjected to consistent force and has a consistent cutting amount throughout the circumference. It ensures that when the wafer rotates to any circumferential angle, the cutter wheel 61 can cut an arc-shaped notch with consistent width and depth. This fundamentally avoids the coating liquid accumulation problem caused by uneven processing, reduces stress concentration at the wafer edge, reduces edge chipping, improves the edge trimming quality of the wafer, and thus improves the quality and yield of the 3D stacked chip.

[0029] Furthermore, in the traditional trimming process, the cutter wheel 61 rotates in a fixed axial position, and only a small area of ​​the cutter wheel 61 rotates axially (such as...). Figure 9 The abrasive grains in the circumferential area (where the black dots are shown) continuously contact and rub against the wafer edge, generating concentrated grinding heat from the continuously participating abrasive grains. If this heat cannot be carried away by the coolant in time, it can lead to excessively high local temperatures on the cutting wheel, potentially causing thermal damage (microcracks) to the wafer edge or premature failure of the bonding agent on the cutting wheel surface. Furthermore, the continuous operation of the abrasive grains participating in the cutting process causes them to wear down and become dull quickly, while the abrasive grains in other axial areas of the cutting wheel hardly participate in the cutting process. This causes the cutting wheel 61 to quickly lose its original shape accuracy and reduce the edge trimming accuracy. Therefore, in step S4, the cutting wheel is oscillated in the X direction. This means that at one moment, the abrasive grains on the left side of the cutting wheel 61 may contact the wafer, and at the next moment, the cutting contact point moves to the middle of the cutting wheel 61, and at the next moment after that, the cutting contact point moves to the right side of the cutting wheel 61. In this way, individual abrasive grains no longer cut continuously but work intermittently. When the cutter wheel 61 moves axially, the abrasive grain can withdraw from the contact area and wait for the coolant to wash away the heat until the cutter wheel 61 swings back, at which point it contacts the workpiece again. This intermittent working mode greatly improves the heat dissipation conditions of individual abrasive grains, avoids local overheating, and distributes the wear evenly across the axial width of the cutter wheel. This significantly delays shape distortion in specific areas of the cutter wheel, allowing the cutter wheel to maintain stable cutting performance and contour accuracy for a longer period of time, thereby ensuring the edge trimming accuracy of the wafer.

[0030] In a further embodiment, since the edges of the annular step on the wafer are relatively fragile, directly using a large cutting amount during cutting may cause the wafer to chip or crack. Therefore, a staged feed method can be adopted. First stage: the cutter wheel 61 cuts into the wafer at a first feed ratio; second stage: the cutter wheel 61 cuts the wafer at a second feed ratio; third stage: the cutter wheel 61 cuts the wafer at a third feed ratio. Here, the feed ratio is the ratio of the depth to the width of the annular step's edge cut by the cutter wheel 61, where depth refers to the cutting dimension in the Z-axis and width refers to the cutting dimension in the Y-axis. Figure 10 The feed rates of the cutting wheel 61 in the first, second, and third stages are indicated by green, yellow, and red, respectively. The first feed rate is relatively small, allowing for a gentler cut into the corners of the wafer's annular step, avoiding damage to the wafer edges from cutting impact. The second feed rate is greater than the first, gradually increasing the feed amount after initial entry to accelerate cutting and improve processing efficiency. The third feed rate is smaller than the second, smoothing the edges between the wafer's upper surface and the arc-shaped notch, preventing the accumulation of colloid at the wafer's upper surface edges, reducing stress concentration at the edges, and avoiding scratches to other wafers during bonding caused by sharp corners on the upper surface edges. The contour formed in the third stage covers the contours formed in the first two stages. Specifically, in the third stage, the wafer rotates at least one revolution so that the cutting contour of the third stage covers the entire circumference of the wafer. Small Y-axis movements of the cutting wheel 61 during the segmented feed process can be achieved by adding a Y-axis moving track to the moving mechanism or by adding a Y-axis micro-motion mechanism between the spindle of the cutting wheel 61 and the moving mechanism.

[0031] By using a phased feeding method, an intelligent machining process is achieved, from gentle entry to efficient cutting and then to finishing and smoothing. This improves efficiency while ensuring the accuracy of the arc-shaped notch profile and the surface quality of the wafer.

[0032] In another embodiment, an offset determination step is included between steps S2 and S3. Specifically, when the offset exceeds an offset threshold, the wafer is moved and repositioned on the stage 50 using a robotic arm of the wafer edge trimming device. This process of obtaining the offset is repeated until the offset is less than the offset threshold, at which point edge trimming is performed. In other words, when the offset is large, dynamic trimming is not used to dynamically compensate for the offset; instead, the wafer is reset using a robotic arm until the offset falls within the offset threshold range. When the offset is small, the offset is compensated by moving the cutter wheel 61 or the stage 50.

[0033] Since the cutting wheel 61 will wear during the dressing process, it is necessary to monitor the wear of the cutting wheel 61 in real time or in stages. For example, after processing a preset number of wafers, the current diameter of the cutting wheel 61 can be detected using a test wafer to determine the amount of wear on the cutting wheel 61, and the feed rate of the cutting wheel 61 can be adjusted based on the amount of wear. Specifically, the length of the cut formed by the cutting wheel 61 when cutting a preset depth on the test wafer can be detected, and the current diameter of the cutting wheel 61 can be determined based on the preset depth and the length of the cut.

[0034] In a more specific implementation, the steps for determining the wafer center are as follows: pick four points on the edge of the wafer, and take three of these points to find the center of the wafer, thus obtaining four centers in total. Then, arbitrarily select three of these four centers to determine the wafer center.

[0035] In actual processing, due to Figure 4 The wafer trimming device shown includes only a longitudinal track 30 and a stage 50 that moves along the longitudinal track 30. This trimming device can only trim one wafer at a time, and the inspection and adjustment of the wafer on the stage can only be performed after the previous wafer has been trimmed and the stage 50 has been cleaned. This results in long idle time for the cutter wheel, significant energy waste, and low wafer processing efficiency. Furthermore, from equipment startup to shutdown (including inspection and adjustment processes), the spindle 62 rotates at high speed continuously to avoid frequent starts and stops of the spindle 62 and its connected cutter wheel 61. This leads to reduced stability of the trimming assembly 60, component wear, and energy waste. Additionally, the vibration of the trimming assembly 60 reduces the inspection accuracy of the connected inspection mechanism 70 during inspection. Therefore, as... Figure 11 This illustration shows a schematic diagram of a wafer trimming apparatus 100 according to another preferred embodiment of this application, which can also be used to perform the aforementioned dynamic wafer edge trimming method. The wafer trimming apparatus 100 includes: The frame includes a crossbeam 10 and two parallel longitudinal rails 30 below the crossbeam 10; Two stages 50 are respectively set on two longitudinal tracks 30 and can slide along the longitudinal tracks 30, used to carry the wafer and drive the wafer to rotate; Two trimming assemblies 60 are mounted on the crossbeam 10 via two movable components. The movable components may include a transverse slide 81 slidable along a transverse track 11 on the crossbeam 10 and a vertical slide 82 slidable along a vertical track on the transverse slide 81. The transverse movement (X-direction) of the transverse slide 81 and the vertical movement (Z-direction) of the vertical slide 82 enable the transverse and / or vertical movement of the trimming assembly 60 connected thereto, or the detection mechanism 70 described below. Each trimming assembly 60 may include a blade wheel 61 extending laterally along its axis. The blade wheel 61 is driven by a spindle 62 and rotates continuously during the operation of the wafer trimming apparatus 100.

[0036] The wafer trimming apparatus 100 is configured to perform two wafer trimming processes. During the trimming process, the stage 50 can move to align the X-axis diameter of the untrimmed wafer with the longitudinal position of the cutting wheel 61. Driven by the moving component, two trimming assemblies 60 move laterally along the crossbeam 10, causing the two cutting wheels 61 to move synchronously to both ends of the wafer's lateral diameter, cutting the wafer into annular notches with right-angled steps. Additionally, the stage 50 can move to align one end of the wafer's Y-axis diameter with the longitudinal position of the cutting wheel 61. One of the two trimming assemblies 60 moves laterally until its cutting wheel 61 is at both ends of the wafer's longitudinal diameter and synchronously contacts the corner of the right-angled step, cutting the corner into an arc-shaped notch and removing adhesive bumps accumulated at the corner during adhesive application. This reduces adhesive buildup at the wafer edge, preventing wafer chipping or metal exposure (such as exposed copper) in subsequent processes.

[0037] like Figures 11-13 As shown, the inspection mechanism 70 and the two trimming components 60 of the wafer trimming apparatus 100 are arranged relatively independently. The inspection mechanism 70 is located on the upstream side of the crossbeam 10, and the two trimming components 60 are located on the downstream side of the crossbeam 10. After the wafer on the stage 50 completes inspection in the inspection area on the upstream side of the crossbeam, it moves with the stage 50 to the cutting area on the downstream side of the crossbeam 10 for trimming. The inspection area and the cutting area are as follows: Figure 13 The dashed boxes on both sides of the beam are shown. In this article, upstream and downstream refer to the workflow or wafer transport path. Typically, the wafer undergoes inspection before trimming; therefore, the inspection unit 70 is located upstream (i.e.,...). Figure 13 Viewed from above the crossbeam 10), the trimming component 60 is located downstream (i.e., above the crossbeam 10). Figure 13 (View from below the crossbeam 10). The wafer trimming device 100 allows wafers on one stage 50 to be trimmed downstream of the crossbeam 10, while wafers on another stage 50 are inspected upstream of the crossbeam 10. Both the trimming assembly 60 and the inspection mechanism 70 can slide across two longitudinal tracks 30 to alternately trim and inspect wafers on the two stages 50. The alternating trimming mentioned here includes one or both of the following processes: wafer dicing with dual trimming assemblies 60 to form annular steps and angle trimming with a single trimming assembly 60 to form an arc-shaped notch.

[0038] Specifically, such as Figure 12The inspection mechanism 70 may include a center detector 74 mounted to the crossbeam 10 via another movable component. The center detector 74 is configured to pick up four points on the edge of the wafer, and select three of these points to determine the center. This process is repeated four times to obtain four centers in total. The center obtained by selecting three of the four centers is then determined as the wafer center. Preferably, if one of the four centers deviates from the position of the other three centers by more than a threshold, that center is discarded, or the inspection is repeated. Then, the wafer trimming device 100 adjusts the position of the wafer so that the wafer center is aligned with the center of the calibrated stage 50, thereby ensuring precise alignment between the wafer and the stage 50, which rotate concentrically. Specifically, the center detector 74 may be a vision detector with a high-magnification lens.

[0039] The inspection mechanism 70 may also include a thickness detector 75 mounted to the crossbeam 10 via another movable component. The thickness detector 75 is configured to detect the height of a plurality of height measurement points on the upper surface of the wafer. These height measurement points are circumferentially evenly distributed along the outer edge of the upper surface of the wafer. The depth of cutter wheel 61 is adjusted based on the height of the height measurement points, thereby ensuring that the annular cut or arc-shaped notch has uniform dimensions throughout the entire circumference of the wafer. The thickness detector 75 may be a point laser rangefinder, which determines the height of the height measurement points on the wafer surface by emitting a laser beam into the wafer and receiving the returned laser beam.

[0040] Additionally, the inspection mechanism 70 may also include a cutter wheel detector 76, configured to detect the length of the kerf formed when the cutter wheel 61 cuts a preset depth on the test wafer, and determine the diameter of the cutter wheel 61 based on the geometric relationship between the preset depth, the length of the kerf, and the diameter of the cutter wheel. Furthermore, the feed rate of the cutter wheel 61 is determined based on the diameter of the cutter wheel 61, where the geometric relationship is: the square of the cutter wheel radius = the square of (cutter wheel radius - preset depth) + the square of (kerf / 2). Further, the wafer trimming device 100 is also configured to detect the current diameter of the cutter wheel 61 using the test wafer after processing a preset number of wafers, to monitor the wear of the cutter wheel 61 in a timely manner, and then adjust the feed rate of the cutter wheel 61 based on the wear. Specifically, the cutter wheel detector 76 may be a vision detector with a low-magnification lens.

[0041] Therefore, according to the wafer trimming apparatus of this application, by independently setting the inspection mechanism 70 and the trimming assembly 60, the impact of vibration caused by the high-speed rotation of the spindle 62 and the cutter wheel 61 of the trimming assembly 60 on the inspection accuracy of the inspection mechanism 70 can be reduced, thereby improving the inspection accuracy and reliability of the inspection mechanism 70. Furthermore, the separate setting of inspection and trimming can effectively reduce the splashing of cooling water and processing debris onto the inspection mechanism 70 during the trimming process, preventing a decrease in the accuracy of the inspection mechanism 70 or damage to its components. In addition, inspection and trimming can be carried out simultaneously. By simply adding a longitudinal track 30 and a stage 50, two parallel work lines can be realized, greatly improving the wafer processing efficiency, i.e., WPH. For manufacturers or customers with requirements on equipment floor space, this can greatly improve the processing efficiency per unit floor space, reduce wafer manufacturing costs, and improve the utilization rate of site resources.

[0042] According to another aspect of this application, a wafer trimming apparatus is also provided for performing a dynamic wafer edge trimming method, comprising: The detection module is used to detect the height of the wafer edge and the offset of the wafer center; The control module is used to control the movement of the cutter wheel and / or the stage based on the detection results of the detection module; The execution module, including the tool wheel and stage, is used to execute the instructions of the control module to perform dynamic trimming of the wafer edges.

[0043] The above embodiments are only used to illustrate the embodiments of this application, and are not intended to limit the embodiments of this application. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the embodiments of this application. Therefore, all equivalent technical solutions also fall within the scope of the embodiments of this application, and the patent protection scope of the embodiments of this application should be defined by the claims.

Claims

1. A method for dynamic trimming of wafer edges, characterized in that, include: Place the wafer on the stage; Detect the height of the entire wafer circumference and obtain the offset L of the wafer center relative to the stage center on the XY plane; Edge trimming is performed by contacting the edges of the annular steps at the wafer edge with the cutting wheel to cut them into arc-shaped notches, in order to avoid the accumulation of adhesive bumps at the edges of the annular steps when applying adhesive to the wafer surface. The cutter wheel can move along the X and Z directions and contacts the wafer at one end of the wafer's Y-direction diameter; The feed rate of the cutter wheel is set based on the center of the stage and dynamically compensated based on the offset. The X-axis compensation is L*cos(a), where a is the stage rotation angle. The cutter wheel has an additional oscillating motion in the X-axis to even out the wear of the cutter wheel. The additional oscillation range is smaller than the width of the cutter wheel.

2. The wafer edge dynamic trimming method as described in claim 1, characterized in that, During edge trimming, the Z-axis compensation of the cutter wheel is the difference between the wafer's full circumference height and the height of the center of the wafer's upper surface.

3. The wafer edge dynamic trimming method as described in claim 1, characterized in that, During edge trimming, the stage and the cutter wheel work together to compensate for the offset. The Y-axis linkage compensation of the stage is L*sin(a).

4. The wafer edge dynamic trimming method as described in claim 1, characterized in that, During edge trimming, the cutter wheel is fed in stages: Phase 1: The cutter wheel cuts into the wafer at the first feed ratio; Second stage: The cutter wheel cuts the wafer at the second feed ratio; Third stage: The cutter wheel cuts the wafer at the third feed ratio; The feed ratio is the ratio of the depth to the width of the edge of the annular step cut by the tool wheel. The first feed ratio is smaller than the second feed ratio to avoid damage to the wafer edge by the cutting impact force. The third feed ratio is smaller than the second feed ratio to smooth the edge between the upper surface of the wafer and the arc notch. The profile formed in the third stage covers the profile formed in the first two stages.

5. The wafer edge dynamic trimming method as described in claim 1, characterized in that, When the offset is greater than the offset threshold, the robot arm of the wafer edge trimming device moves the wafer and repositions it on the stage, and repeats the step of obtaining the offset until the offset is less than the offset threshold, after which edge trimming is performed.

6. The wafer edge dynamic trimming method as described in claim 1, characterized in that, The method further includes: after processing a preset number of wafers, using a test wafer to detect the current diameter of the cutter wheel to determine the wear amount of the cutter wheel, and adjusting the feed rate of the cutter wheel based on the wear amount; The test involves detecting the length of the cut formed when the cutting wheel cuts a preset depth on the test wafer, and determining the current diameter of the cutting wheel based on the preset depth and the length of the cut.

7. The wafer edge dynamic trimming method as described in claim 1, characterized in that, The steps for determining the wafer center are as follows: pick four points on the edge of the wafer, and take three of these points to find the center of the wafer, resulting in four centers. Then, randomly select three of these four centers to determine the wafer center.

8. A wafer edge trimming apparatus for performing the wafer edge dynamic trimming method as described in any one of claims 1-8, comprising: The stage can slide along the longitudinal track and is used to horizontally support the wafer and drive the wafer to rotate; The trimming assembly is mounted on the crossbeam by a moving assembly and moves laterally and vertically by the moving assembly. The trimming assembly includes a cutting wheel for cutting the edge of the wafer. Inspection facilities are used to inspect wafers before trimming.

9. A wafer edge trimming apparatus for performing the wafer edge dynamic trimming method as described in any one of claims 1-8, comprising: The detection module is used to detect the height of the wafer edge and the offset of the wafer center; The control module is used to control the movement of the cutter wheel and / or the stage based on the detection results of the detection module; The execution module, including the tool wheel and stage, is used to execute the instructions of the control module to perform dynamic trimming of the wafer edges.

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