Scribing machine and scribing method

Abstract

The application provides a scribing machine and a scribing method. The scribing machine comprises a scribing table, a rack, a lifting driving mechanism, a lifting seat, a scribing assembly and a thickness measuring camera. The scribing table is used for carrying a wafer to be scribed, and the wafer is attached to a blue film. The rack is arranged above the scribing table, and the lifting driving mechanism is arranged on the rack. The lifting seat is slidably installed on the rack and connected to a movable part of the lifting driving mechanism. The thickness measuring camera and the scribing assembly are arranged side by side on the lifting seat, and the lifting driving mechanism is used for driving the thickness measuring camera and the scribing assembly to lift. The thickness measuring camera is configured to measure the thickness of the wafer on the scribing table. The scribing assembly is configured to scribe the wafer based on the thickness of the wafer. The scribing machine provided by the application can implement automatic thickness measurement of the wafer on the scribing table, so that the scribing assembly can implement scribing operation on the wafer based on the thickness information of the wafer. The application reduces the scribing cost and improves the scribing efficiency.

Description

Technical Field

[0001] This application relates to the field of semiconductor device manufacturing, specifically a dicing machine and dicing method. Background Technology

[0002] The dicing process is a crucial step in the actual semiconductor device manufacturing process. It is performed using a dicing machine, which includes components such as a spindle, a cutter, and a dicing stage. The dicing process involves the spindle driving a high-speed rotating cutter downwards to contact the wafer on the dicing stage. The spindle then drives the cutter to move along a predetermined dicing path, closely adhering to the wafer, thereby dicing the wafer into several dies of predetermined size.

[0003] To ensure the dicing blade cuts through the wafer and prevents it from contacting the dicing stage's bearing surface and causing damage, the wafer thickness needs to be measured before dicing. Based on this measurement, the maximum cutting depth of the dicing blade on the wafer is determined. This ensures that the dicing blade cuts through the wafer without cutting through the blue film adhering to it. For example, when the blue film thickness is 0.1 mm, the maximum cutting depth can be set to the wafer thickness + 0.05 mm.

[0004] Existing dicing machines cannot perform automatic thickness measurement on wafers. Therefore, before dicing, wafers need to be measured using specialized thickness measurement equipment, which will inevitably increase dicing costs and reduce dicing efficiency. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the first aspect of this application provides a dicing machine, which adopts the following technical solution:

[0006] A dicing machine includes: a dicing table, a frame, a lifting drive mechanism, a lifting base, a dicing assembly, and a thickness measuring camera, wherein:

[0007] The dicing stage is used to hold the wafers to be diced, wherein the wafers are attached to the blue film;

[0008] The frame is set above the dicing table, and the lifting drive mechanism is set on the frame;

[0009] The lifting base is slidably mounted on the frame and connected to the moving parts of the lifting drive mechanism. The thickness measuring camera and the scribing assembly are arranged side by side on the lifting base. The lifting drive mechanism is used to drive the thickness measuring camera and the scribing assembly to move up and down.

[0010] The thickness measurement camera is configured to measure the thickness of a wafer located on a dicing stage;

[0011] The dicing assembly is configured to dice wafers based on wafer thickness.

[0012] The dicing machine provided in this application has a thickness measuring camera mounted on its lifting platform, which can move synchronously with the dicing assembly. Before the actual dicing process, the thickness measuring camera can automatically measure the thickness of the wafer on the dicing stage. This allows the dicing assembly to perform the dicing operation based on the wafer's thickness information. Compared to existing dicing methods that use dedicated thickness measuring equipment, the dicing machine of this application reduces dicing costs and improves dicing efficiency.

[0013] In some embodiments, the dicing stage is connected to the translation drive module, which is used to drive the dicing stage to translate; or, the frame is connected to the translation drive module, which is used to drive the frame to translate.

[0014] By driving the dicing stage to translate relative to the dicing assembly through the translation drive module, or by driving the dicing assembly to translate relative to the dicing stage through the translation drive module, the dicing assembly can be inserted into the wafer on the dicing stage and the wafer can be diced.

[0015] In some embodiments, the dicing stage has adsorption holes for adsorbing the blue film on its bearing surface, or the dicing stage has an annular groove on its periphery, and the dicing machine also includes an annular tension ring that tightens and fixes the periphery of the blue film in the groove.

[0016] Two methods for fixing the blue film are provided, both of which can ensure that the blue film is positioned on the bearing surface of the dicing stage, thereby achieving wafer positioning and preventing wafer displacement during the dicing process.

[0017] In some embodiments, the lifting drive mechanism includes a lead screw motor, a lead screw, and a nut. The lead screw motor is fixedly mounted on the frame, the lead screw is arranged vertically, the upper end of the lead screw is connected to the drive end of the lead screw motor via a coupling, the lower end of the lead screw is rotatably connected to the frame, the nut is screwed onto the lead screw, and the lifting seat is fixedly connected to the nut.

[0018] The lifting platform is driven by a lead screw module. Once the lifting platform is in position, it can be stably maintained at the current height without any unexpected lifting or lowering, thereby improving the thickness measurement accuracy of the thickness measuring camera and ensuring the dicing effect of the dicing component.

[0019] In some embodiments, the dicing assembly includes a connecting seat, a spindle, and a cutter, wherein the upper end of the connecting seat is connected to a mounting base, the spindle is mounted on the lower end of the connecting seat, the cutter is vertically mounted on the spindle, and the spindle is used to drive the cutter to rotate.

[0020] A simple dicing assembly is provided, which drives a cutter to rotate at high speed via a spindle to dice wafers.

[0021] In some embodiments, the dicing machine further includes a purging mechanism, which includes an air block and a blowing pipe, wherein: the air block is connected to the bottom of the camera, an air chamber is provided inside the air block, the air chamber is connected to an external compressed air source via an air connector mounted on the air block, and the blowing pipe is inserted into the air block and communicates with the air chamber; the blowing end of the blowing pipe faces the dicing stage.

[0022] During the dicing process, the purging mechanism can promptly blow away the material residue generated during the dicing process, further improving the dicing effect.

[0023] This application also provides a dicing method, which is performed by the dicing machine described in any of the above claims, the dicing method comprising:

[0024] The lifting drive mechanism drives the thickness measuring camera to rise and fall. During the lifting and falling process, the thickness measuring camera focuses on the scouring table to obtain the first focal length of the thickness measuring camera relative to the bearing surface of the scouring table.

[0025] Place the wafer onto the support surface of the dicing stage, and attach the wafer to the blue film;

[0026] The lifting drive mechanism drives the thickness measuring camera to rise and fall. During the lifting and falling process, the thickness measuring camera focuses on the wafer to obtain the second focal length of the thickness measuring camera relative to the upper surface of the wafer.

[0027] The thickness of the wafer is calculated based on the second focal length and the first focal length;

[0028] The lifting drive mechanism drives the dicing assembly to descend to the target height based on the wafer thickness, and controls the dicing assembly to dic the wafer.

[0029] The dicing method provided in this application can automatically measure the thickness of wafers on a dicing stage, thereby enabling the dicing assembly to perform dicing operations on the wafers based on the wafer thickness information, thus reducing dicing costs and improving dicing efficiency.

[0030] In some optional embodiments, a lifting drive mechanism drives the thickness measuring camera to move up and down. During the lifting and lowering process, the thickness measuring camera focuses on the scouring stage to obtain a first focal length of the thickness measuring camera relative to the bearing surface of the scouring stage, including:

[0031] The lifting drive mechanism drives the thickness measuring camera to step up or step down within the first focusing range according to the first step length. When stepping to each height, the thickness measuring camera takes a first image of the dicing table, obtains the clarity of the first image, and synchronously controls the thickness measuring camera to step to the next height.

[0032] The second focus range is determined based on the sharpness of the first image;

[0033] The lifting drive mechanism drives the thickness measuring camera to step up or step down within the second focusing range according to the second step length. When stepping to each height, the thickness measuring camera takes a second image of the dicing stage and obtains the clarity of the second image. Simultaneously, the thickness measuring camera is controlled to step to the next height. The first step length is greater than the second step length, and the first step length is an integer multiple of the second step length.

[0034] The first focal length is determined based on the sharpness of the second image.

[0035] First, use a longer first step length to perform coarse focusing within the first focusing range to find the second focusing range, which includes the optimal focusing position. Then, use a shorter second step length to perform fine focusing within the second focusing range to find the optimal focusing position of the thickness measuring camera relative to the grading stage, thereby obtaining the first focal length of the thickness measuring camera relative to the bearing surface of the grading stage.

[0036] In some optional embodiments, a lifting drive mechanism drives the thickness measuring camera to move up and down. During the lifting and lowering process, the thickness measuring camera focuses on the wafer to obtain a second focal length of the thickness measuring camera relative to the upper surface of the wafer, including:

[0037] The lifting drive mechanism drives the thickness measuring camera to step up or step down within the first focusing range according to the first step length. When stepping to each height, the thickness measuring camera takes a first image of the wafer and obtains the clarity of the first image, and simultaneously controls the thickness measuring camera to step to the next height.

[0038] The second focus range is determined based on the sharpness of the first image;

[0039] The lifting drive mechanism drives the thickness measuring camera to step up or step down within the second focusing range according to the second step length. When stepping to each height, the thickness measuring camera takes a second image of the wafer and obtains the clarity of the second image. Simultaneously, the thickness measuring camera is controlled to step to the next height. The first step length is greater than the second step length, and the first step length is an integer multiple of the second step length.

[0040] The second focal length is determined based on the sharpness of the second image.

[0041] First, coarse focusing is performed within the first focusing range using a longer first step length to find the second focusing range, which includes the optimal focusing position. Then, fine focusing is performed within the second focusing range using a shorter second step length to find the optimal focusing position of the thickness measuring camera relative to the wafer, thereby obtaining the second focal length of the thickness measuring camera relative to the upper surface of the wafer.

[0042] In some embodiments, the lifting drive mechanism drives the dicing assembly to descend to a target height based on the wafer thickness, controlling the dicing assembly to dic the wafer, including:

[0043] The maximum cutting depth of the cutter on the wafer is determined based on the wafer thickness, and the radius of the cutter and the length of the target groove are obtained.

[0044] Determine the initial feed rate and the mid-section slicing rate of the cutter, wherein the mid-section slicing rate is greater than the initial feed rate;

[0045] The feed stroke of the cutter is calculated based on the cutter radius and the maximum cutting depth;

[0046] Calculate the mid-section stroke of the cutter based on the target groove length and the feed stroke;

[0047] Acceleration is calculated based on the initial feed rate, the mid-section dicing speed, and the feed stroke.

[0048] Control the cutter to accelerate its entry into the wafer using an initial feed rate and acceleration;

[0049] Control the cutter to cut the wafer at the mid-section dicing speed until the cutter's dicing stroke reaches the mid-section stroke;

[0050] The cutter is controlled to cut the wafer by adjusting the mid-section dicing speed and acceleration.

[0051] Use a low-speed cutting motion at the start of the cutter's advance, then gradually accelerate to a high speed. Once the cutting force on the blade has stabilized, use a high-speed, uniform cutting motion. When exiting the cutter, gradually decelerate from the high speed back to the initial advance speed until the cutting is complete. This ensures both cutting efficiency and the quality of the cut slices, preventing edge chipping during the advance and exit. Attached Figure Description

[0052] Figure 1 This is a schematic diagram of the dicing machine in the embodiments of this application;

[0053] Figure 2 for Figure 1 A partial structural diagram of the dicing machine in China;

[0054] Figure 3 This is a schematic diagram of the dicing process of the cutter in the embodiment of the application.

[0055] Figures 1 to 3 Includes:

[0056] Dicing stage 1: Groove 11, tension ring 12;

[0057] Rack 2;

[0058] Lifting drive mechanism 3: lead screw motor 31, lead screw 32, nut 33;

[0059] Lifting seat 4;

[0060] Dicing assembly 5: Connector 51, spindle 52, cutter 53;

[0061] Thickness measuring camera 6;

[0062] Purging mechanism 7: air block 71, air inlet 72, air blowing pipe 73;

[0063] 100 wafers, 200 blue film. Detailed Implementation

[0064] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0065] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used 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. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0066] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0067] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0068] like Figures 1 to 2 As shown, the dicing machine in this embodiment includes a dicing table 1, a frame 2, a lifting drive mechanism 3, a lifting base 4, a dicing assembly 5, and a thickness measuring camera 6, wherein:

[0069] The dicing stage 1 is used to hold the wafer 100 to be diced, wherein the wafer 100 is attached to the blue film 200.

[0070] The frame 2 is positioned above the dicing table 1, and the lifting drive mechanism 3 is positioned on the frame 2.

[0071] The lifting base 4 is slidably mounted on the frame 1 and connected to the moving part of the lifting drive mechanism 3. The thickness measuring camera 6 and the scribing assembly 5 are arranged side by side on the lifting base 4. The lifting drive mechanism 4 is used to drive the thickness measuring camera 6 and the scribing assembly 5 to lift synchronously.

[0072] The thickness measurement camera 6 is configured to measure the thickness of a wafer located on the dicing stage 1.

[0073] The dicing assembly 5 is configured to dice wafer 100 based on the thickness of wafer 100.

[0074] The working process of the dicing machine in this embodiment of the application is as follows:

[0075] Before placing the wafer 100 to be diced onto the dicing stage 1, the thickness measuring camera 6 is first moved up and down by the lifting drive mechanism 3. During the moving process, the thickness measuring camera 6 focuses on the dicing stage 1 to determine the first focal length of the thickness measuring camera 6 relative to the dicing stage 1, i.e. Figure 2 The distance shown is between the lens of the thickness measuring camera 6 and the bearing surface B of the dicing stage 1.

[0076] Subsequently, the wafer 100, adhered to the blue film 200, is placed on the dicing stage 1. Then, the thickness measuring camera 6 is first moved up and down via the lifting drive mechanism 3. During this movement, the thickness measuring camera 6 focuses on the wafer 100 to determine its second focal length relative to the wafer 100. Figure 2 The distance between the lens of the thickness measuring camera 6 and the upper surface A of the wafer 100 is shown.

[0077] from Figure 2 As can be seen, the difference between the first focal length and the second focal length is the thickness of wafer 100 and blue film 200. The thickness of blue film 200 is a known value, for example, the thickness of the blue film 200 used is 0.1mm. Therefore, the thickness of wafer 100 can be automatically calculated using the first focal length, the second focal length, and the thickness of blue film 200.

[0078] Optionally, the first focal length and the second focal length measured by the thickness measuring camera 6 can be obtained by a PLC connected to the thickness measuring camera 6. The PLC then calculates the thickness of the wafer 100 based on the first focal length, the second focal length and the thickness of the blue film 200.

[0079] Finally, the dicing assembly 5 dices the wafer 100 based on its thickness, ensuring that it cuts through the wafer 100 without touching the dicing stage 1.

[0080] As can be seen, the dicing machine provided in this application embodiment automatically measures the thickness of the wafer on the dicing stage using a thickness measuring camera before performing the actual dicing. This enables the dicing assembly to perform the dicing operation on the wafer based on the wafer's thickness information. Compared to existing dicing methods that use dedicated thickness measuring equipment to measure the wafer thickness, the dicing machine in this application embodiment reduces dicing costs and improves dicing efficiency.

[0081] In one alternative embodiment, the dicing stage 1 is connected to the translation drive module. When the dicing assembly 5 determines the maximum cutting depth based on the thickness of the wafer 100 and descends to the dicing height, the translation drive module drives the dicing stage 1 to translate toward the dicing assembly 5, so that the dicing assembly 5 cuts into the wafer 100 on the dicing stage 1 and completes the dicing of the wafer 100.

[0082] In another alternative embodiment, the frame 2 is connected to the translation drive module. When the dicing assembly 5 determines the maximum cutting depth based on the thickness of the wafer 100 and descends to the dicing height, the translation drive module drives the frame 2 to translate, thereby driving the dicing assembly 5 to cut into the wafer 100 on the dicing stage 1 and complete the dicing of the wafer 100.

[0083] like Figure 2 As shown, optionally, an annular groove 11 is provided on the periphery of the dicing stage 1. The dicing machine also includes an annular tension ring 12, which tightens and fixes the periphery of the blue film 200 within the groove 11. This ensures that the blue film 200 is positioned on the bearing surface of the dicing stage 1, thereby achieving the positioning of the wafer 100 adhered to the blue film 200 and preventing the wafer 100 from shifting during the dicing process. Alternatively, adsorption holes can be provided on the bearing surface of the dicing stage 1 to adsorb and position the blue film on the bearing surface of the dicing stage 1.

[0084] like Figure 1 As shown, optionally, the lifting drive mechanism 3 includes a lead screw motor 31, a lead screw 32, and a nut 33. The lead screw motor 31 is fixedly mounted on the frame 2. The lead screw 32 is arranged in a vertical direction. The upper end of the lead screw 32 is connected to the drive end of the lead screw motor 31 via a coupling. The lower end of the lead screw 32 is rotatably connected to the frame 2. The nut 33 is screwed onto the lead screw 32. The lifting seat 4 is fixedly connected to the nut 33.

[0085] The lead screw motor 31 drives the lead screw 32 to rotate, which in turn drives the nut 33 to rise and fall smoothly along the lead screw 32, ultimately causing the lifting seat 4 to rise and fall synchronously. The lifting seat 4 is driven to rise and fall using a lead screw module consisting of the lead screw motor 31, lead screw 32, and nut 33. Once the lifting seat is in position, it can be stably maintained at the current height, thus preventing accidental rises and falls, improving the thickness measurement accuracy of the thickness measuring camera 6, and preventing the scribing assembly 5 from shaking during scribing, thereby improving the scribing effect.

[0086] like Figure 1 As shown, optionally, the dicing assembly 5 includes a connecting seat 51, a spindle 52, and a cutter 53. The upper end of the connecting seat 51 is connected to the mounting seat 4, the spindle 52 is mounted on the lower end of the connecting seat 51, and the cutter 53 is vertically mounted on the spindle 52. The spindle 52 is used to drive the cutter 53 to rotate.

[0087] When the dicing stage 1 and the dicing assembly 5 move relative to each other, the high-speed rotating cutter 53 cuts into the wafer 100 and finally completes the dicing of the wafer 100.

[0088] Based on the same concept, this application provides a dicing method, which is implemented by the dicing machine provided in any of the above embodiments. The dicing method in the embodiments of this application includes the following steps:

[0089] S1. The lifting drive mechanism 3 drives the thickness measuring camera 6 to rise and fall. During the rising and falling process, the thickness measuring camera 6 focuses on the scouring table 1 to obtain the first focal length of the thickness measuring camera 6 relative to the bearing surface of the scouring table 1.

[0090] S2. Place wafer 100 on the dicing stage 1, wherein wafer 100 is attached to blue film 200.

[0091] S3, the lifting drive mechanism 3 drives the thickness measuring camera 6 to lift and lower. During the lifting and lowering process, the thickness measuring camera 6 focuses on the wafer 100 to obtain the second focal length of the thickness measuring camera 6 relative to the upper surface of the wafer 100.

[0092] S4. Calculate the thickness of the wafer based on the second focal length and the first focal length.

[0093] S5, the lifting drive mechanism 3 drives the dicing assembly 5 to descend to the target height based on the thickness of the wafer, and controls the dicing assembly to dice the wafer.

[0094] The dicing method in this application embodiment can automatically measure the thickness of the wafer on the dicing stage before dicing, thereby enabling the dicing component to perform dicing operations on the wafer based on the wafer thickness information, thus reducing dicing costs and improving dicing efficiency.

[0095] Optionally, the specific implementation process of step S1 is as follows:

[0096] S11. The lifting drive mechanism 3 drives the thickness measuring camera 6 to step up or step down within the first focusing range according to the first step length. When stepping to each height, the thickness measuring camera 6 takes a first image of the dicing stage 1, obtains the clarity of the first image, and synchronously controls the thickness measuring camera 6 to step to the next height.

[0097] The first focusing range can be the adjustable range of the thickness measuring camera 6. Of course, in order to narrow down the first focusing range, the approximate range of the optimal focusing position can also be determined based on experience, and this range can be used as the first focusing range.

[0098] For example, in one specific embodiment, the first focusing range has a vertical length of 60mm. The upper endpoint of the first focusing range can be used as the starting point of the stepping motion, and the lower endpoint as the ending point. The lifting drive mechanism 3 drives the thickness measuring camera 6 to descend step by step from the starting point to the ending point, with each step being 3mm longer. Alternatively, the lower endpoint of the first focusing range can be used as the starting point, and the upper endpoint as the ending point. The lifting drive mechanism 3 drives the thickness measuring camera 6 to rise step by step from the starting point to the ending point, with each step being 3mm longer.

[0099] Each time the lifting drive mechanism 3 drives the thickness measuring camera 6 to a certain height, the thickness measuring camera 6 takes a picture of the scouring table 1 to obtain a first image of the scouring table 1. After taking the picture, the thickness measuring camera 6 or the PLC connected to the thickness measuring camera 6 analyzes the first image to calculate its sharpness. At the same time, the lifting drive mechanism 3 drives the thickness measuring camera 6 to the next height. That is to say, the processing thread of the thickness measuring camera 6 acquiring the first image and calculating the sharpness of the first image runs in parallel with the processing thread of the lifting drive mechanism 3 driving the thickness measuring camera 6 to the next height, thereby shortening the focusing time. After completing the stepping, the thickness measuring camera 6 obtains 21 first images and obtains the sharpness data corresponding to the 21 first images.

[0100] S12. Determine the second focus range based on the sharpness of the first image.

[0101] Specifically, the height corresponding to the first image with maximum sharpness is taken as the center position of the second focus range. The two adjacent heights corresponding to the height of the first image with maximum sharpness are taken as the two endpoints of the second focus range.

[0102] Using the previous example, for instance, in 21 first images corresponding to 21 height points, the first image at the 10th height point has the highest sharpness. Therefore, the final determined second focus range is the range between the 9th and 11th height points. The vertical length of the second focus range is 6mm.

[0103] Of course, to improve focusing accuracy, the length of the first step can be shortened to obtain more first images, ultimately shortening the vertical length of the first focusing range.

[0104] S13. The lifting drive mechanism 3 drives the thickness measuring camera 6 to step up or step down within the second focusing range according to the second step length. When stepping to each height, the thickness measuring camera 6 takes a second image of the dicing stage 1 and obtains the clarity of the second image. Simultaneously, the thickness measuring camera 6 is controlled to step to the next height. The first step length is greater than the second step length, and the first step length is an integer multiple of the second step length.

[0105] Using the previous embodiment as an example, the second step length can be set to 1mm. The thickness measuring camera 6 is driven by the lifting drive mechanism 3 to step down or up within the second focusing range between the 9th and 11th height points. Ultimately, five second images corresponding to the five height points are obtained, and the sharpness of the five second images is also obtained accordingly.

[0106] Similarly, to improve focusing accuracy, the second step length can be shortened to obtain a larger number of second images.

[0107] S14. Determine the first focal length based on the sharpness of the second image.

[0108] The height corresponding to the second image with the highest sharpness is selected as the optimal focus position. The distance between this focus position and the bearing surface B of the scribe stage 1 is the first focal length.

[0109] As can be seen, the focusing process in step S1 first uses a longer first step length to perform coarse focusing within the first focusing range, finding a second focusing range that includes the optimal focusing position. Then, a shorter second step length is used to perform fine focusing within the second focusing range, finding the optimal focusing position of the thickness measuring camera relative to the scribe table, thereby obtaining the first focal length of the thickness measuring camera relative to the scribe table's bearing surface. In this way, the first focal length of the thickness measuring camera relative to the scribe table's bearing surface can be obtained quickly and accurately.

[0110] Optionally, the implementation process of step S3 is basically the same as that of step S1, and the implementation process is as follows:

[0111] S31. The lifting drive mechanism drives the thickness measuring camera to step up or step down within the first focusing range along the first step length. When stepping to each height, the thickness measuring camera takes a first image of the wafer and obtains the clarity of the first image, and synchronously controls the thickness measuring camera to step to the next height.

[0112] S32. Determine the second focus range based on the sharpness of the first image.

[0113] S33. The lifting drive mechanism drives the thickness measuring camera to step up or step down within the second focusing range along the second step length. When stepping to each height, the thickness measuring camera takes a second image of the wafer and obtains the clarity of the second image. Simultaneously, the thickness measuring camera is controlled to step to the next height. The first step length is greater than the second step length, and the first step length is an integer multiple of the second step length.

[0114] S34. Determine the second focal length based on the sharpness of the second image.

[0115] The more specific implementation details of steps S31-S34 above are similar to those of steps S11-S14 in the previous text, and will not be described in detail here for the sake of brevity.

[0116] Similarly, in the focusing process of step S3, firstly, a longer first step length is used to perform coarse focusing within the first focusing range to find a second focusing range that includes the optimal focusing position. Then, a shorter second step length is used to perform fine focusing within the second focusing range to find the optimal focusing position of the thickness measuring camera relative to the wafer, thereby obtaining the first focal length of the thickness measuring camera relative to the upper surface of the wafer. In this way, the second focal length of the thickness measuring camera relative to the upper surface of the wafer can be obtained quickly and accurately.

[0117] It should be noted here that the first focus range, first step length, and second step length used in the focusing process of step S3 can be the same as those in step S1, or they can be different from those in step S1.

[0118] As those skilled in the art know, the resistance experienced by the dicing blade during wafer dicing is not uniform. Specifically, the force on the dicing blade gradually increases during its entry into the wafer and gradually decreases during its exit from the wafer. However, the force on the dicing blade remains constant in the middle section of the wafer (i.e., the portion between the entry and exit sections). Existing dicing methods use a fixed dicing speed (i.e., the blade's translational speed relative to the wafer) throughout the entire dicing process, making it difficult to simultaneously achieve dicing efficiency and dicing quality. If the dicing speed is set too high, it can cause chipping of the wafer during the entry or exit process. If the dicing speed is set too low, the dicing efficiency will be too low.

[0119] Therefore, it's advisable to control the cutter to enter or exit the wafer at a lower speed, while performing mid-section dicing at a higher speed. During the feed, as the cutter continues to enter, the force on the cutter gradually increases, and the risk of wafer edge chipping gradually decreases. Therefore, it's possible to gradually increase the feed speed to achieve a higher mid-section dicing speed after the feed is complete. During the exit, as the cutter continues to exit, the force on the cutter gradually decreases, and the risk of wafer edge chipping gradually increases. Therefore, it's advisable to gradually decrease the feed speed.

[0120] Combined Figure 3 As shown, based on the above considerations, optionally, in this embodiment of the application, step S5 is implemented as follows:

[0121] S51. Determine the maximum cutting depth d of the cutter 53 on the wafer 100 based on the thickness of the wafer 100, and obtain the radius R of the cutter 53 and the length L of the target groove.

[0122] For example, the thickness of the blue film 200 is 0.1 mm, and the maximum cutting depth d = the thickness of wafer 100 + 0.05 mm. The radius R of the cutter 53 and the length L of the target groove are fixed values ​​obtained through measurement.

[0123] S52. Determine the initial feed speed V0 of the cutter 53 and the mid-section slicing speed V of the cutter 53, wherein the mid-section slicing speed V is greater than the initial feed speed V0.

[0124] The initial feed rate V0 and the mid-section dicing rate V are set according to the material of the wafer 100 and the dicing requirements. They are generally empirical values ​​or obtained through experiments.

[0125] S53. The feed stroke S of the cutter is calculated based on the radius R and maximum cutting depth d of the cutter 53.

[0126] In addition, such as Figure 3 As shown, the difference between the radius R of the cutting tool 53 and the maximum cutting depth d at half the feed stroke S (S / 2) satisfies the Pythagorean theorem, i.e.: (S / 2) 2 =R 2 -(Rd) 2 Therefore, we can obtain S = 2√2Rd - d 2 .

[0127] S54. Based on the length L of the target groove and the feed stroke S, calculate the mid-section stroke S1 of the cutter.

[0128] The mid-section stroke S1 = the length of the target groove L - the feed stroke S - the exit stroke. Since the exit stroke is equal to the feed stroke S, therefore, S1 = L - 2S.

[0129] S55. Calculate acceleration a based on initial feed rate V0, mid-section dicing speed V, and feed stroke S.

[0130] Optionally, the acceleration 'a' can be set to a constant value, meaning the feed process is uniformly accelerated and the withdrawal process is uniformly decelerated. Then, the acceleration 'a' = (V... 2 -V0 2 ) / 2S.

[0131] S56. Control the cutter 53 to accelerate into the wafer 100 at the initial feed speed V0 and acceleration a.

[0132] S57. Control the cutter 53 to cut the wafer 100 at the mid-section dicing speed V until the dicing stroke of the cutter 53 reaches the mid-section stroke S1.

[0133] S58, control the cutter 53 to decelerate and cut out the wafer 100 at the mid-section dicing speed V and acceleration a.

[0134] Since the speed change during the exit phase is exactly opposite to that during the feed phase in step S55, the speed of the cutter 53 after leaving the wafer 100 drops to the initial feed speed V0.

[0135] As can be seen, in the dicing process of step S5, a low-speed dicing is used at the beginning of the cutting, then the speed is gradually increased to high speed. After the cutting blade 53 is under stable force, a high-speed uniform dicing is used. When exiting the blade, the speed is gradually reduced from high speed to the initial cutting speed until the dicing is completed. In this way, both dicing efficiency and dicing quality can be ensured, and edge chipping is prevented during the cutting and exiting processes.

[0136] In other embodiments, without considering both dicing efficiency and dicing quality, the cutter 53 can be controlled to dice the wafer 100 at a constant speed.

[0137] Optionally, before controlling the cutter 53 in step S56 to accelerate into the wafer 100 at an initial feed speed V0 and acceleration a, step S5 further includes:

[0138] Determine the reserved dicing stroke S0, and control the cutter 53 to move towards the wafer 100 at an initial feed speed V0 at a constant speed of reserved dicing stroke S0, so that the cutter 53 contacts the wafer 100.

[0139] By setting a reserved dicing stroke S0, the impact damage to the cutter 53 caused by the cutter 53 falling directly onto the wafer 100 can be avoided. In addition, the blue film 200 supporting the wafer 100 can also be cut.

[0140] Similarly, optionally, after the cutter 53 in step S58 decelerates and cuts out the wafer 100 at the mid-section dicing speed V and acceleration a, step S5 further includes: controlling the cutter 53 to move away from the wafer 100 at the initial feed speed V0 and move the reserved dicing stroke S0.

[0141] The foregoing has provided a sufficiently detailed and specific description of this application. Those skilled in the art should understand that the descriptions in the embodiments are merely exemplary, and all changes made without departing from the true spirit and scope of this application should fall within the protection scope of this application. The scope of protection claimed in this application is defined by the claims, and not by the above descriptions in the embodiments.

Claims

1. A dicing method, characterized in that, The dicing method is implemented by a dicing machine, which includes a dicing stage, a frame, a lifting drive mechanism, a lifting base, a dicing assembly, and a thickness measuring camera. The dicing stage carries the wafer to be diced, and the wafer is attached to a blue film. The frame is positioned above the dicing stage, and the lifting drive mechanism is mounted on the frame. The lifting base is slidably mounted on the frame and connected to a movable part of the lifting drive mechanism. The thickness measuring camera and the dicing assembly are arranged side-by-side on the lifting base, and the lifting drive mechanism drives the thickness measuring camera and the dicing assembly to move up and down. The thickness measuring camera is configured to measure the thickness of the wafer located on the dicing stage. The dicing assembly is configured to dice the wafer based on its thickness. The slicing method includes: A lifting drive mechanism drives the thickness measuring camera to move up and down. During the lifting process, the thickness measuring camera focuses on the scouring table to obtain a first focal length of the thickness measuring camera relative to the bearing surface of the scouring table, including: The lifting drive mechanism drives the thickness measuring camera to step up or step down within the first focusing range according to the first step length. When stepping to each height, the thickness measuring camera takes a first image of the dicing table and obtains the clarity of the first image, and simultaneously controls the thickness measuring camera to step to the next height. The second focus range is determined based on the sharpness of the first image; The lifting drive mechanism drives the thickness measuring camera to step up or step down within the second focusing range according to the second step length. When stepping to each height, the thickness measuring camera takes a second image of the dicing stage and obtains the clarity of the second image. Simultaneously, the thickness measuring camera is controlled to step to the next height. The first step length is greater than the second step length, and the first step length is an integer multiple of the second step length. The first focal length is determined based on the sharpness of the second image; The wafer is placed on the support surface of the dicing stage, and the wafer is attached to the blue film; A lifting drive mechanism drives the thickness measuring camera to move up and down. During the lifting process, the thickness measuring camera focuses on the wafer to obtain a second focal length of the thickness measuring camera relative to the upper surface of the wafer, including: The lifting drive mechanism drives the thickness measuring camera to step up or step down within the first focusing range according to the first step length. When stepping to each height, the thickness measuring camera takes a first image of the wafer and obtains the clarity of the first image, and simultaneously controls the thickness measuring camera to step to the next height. The second focus range is determined based on the sharpness of the first image; The lifting drive mechanism drives the thickness measuring camera to step up or step down within the second focusing range according to the second step length. When stepping to each height, the thickness measuring camera takes a second image of the wafer and obtains the clarity of the second image. Simultaneously, the thickness measuring camera is controlled to step to the next height. The first step length is greater than the second step length, and the first step length is an integer multiple of the second step length. The second focal length is determined based on the sharpness of the second image; The thickness of the wafer is calculated based on the second focal length and the first focal length; The lifting drive mechanism drives the dicing assembly to descend to a target height based on the thickness of the wafer, and controls the dicing assembly to dice the wafer, including: The maximum cutting depth d of the cutter on the wafer is determined based on the thickness of the wafer, and the radius R of the cutter and the length L of the target groove are obtained. Determine the initial feed speed V0 of the cutter and the mid-section slicing speed V of the cutter, wherein the mid-section slicing speed V is greater than the initial feed speed V0; Using the formula S=2 Calculate the feed stroke S of the cutter; The mid-section stroke S1 of the cutter is calculated using the formula S1=L-2S; Through the formula a=(V 2 -V0 2 Calculate the acceleration a using the formula ) / 2S; The cutter is controlled to accelerate into the wafer at the initial feed speed V0 and the acceleration a; The cutter is controlled to cut the wafer at the mid-section dicing speed V until the cutting stroke of the cutter reaches the mid-section stroke S1; The cutter is controlled to decelerate and cut the wafer at a mid-section dicing speed V and an acceleration a.

2. The dicing method as described in claim 1, characterized in that, The lifting drive mechanism includes a lead screw motor, a lead screw, and a nut. The lead screw motor is fixedly mounted on the frame. The lead screw is arranged vertically. The upper end of the lead screw is connected to the drive end of the lead screw motor via a coupling. The lower end of the lead screw is rotatably connected to the frame. The nut is screwed onto the lead screw. The lifting seat is fixedly connected to the nut.

3. The dicing method as described in claim 1, characterized in that, The dicing assembly includes a connecting seat, a main shaft, and a cutter. The upper end of the connecting seat is connected to the lifting seat, the main shaft is mounted on the lower end of the connecting seat, and the cutter is vertically mounted on the main shaft. The main shaft is used to drive the cutter to rotate.

4. The dicing method as described in claim 1, characterized in that, The dicing machine further includes a purging mechanism, which comprises an air block and an air blowing pipe, wherein: The air block is connected to the bottom of the thickness measuring camera. An air chamber is provided inside the air block. The air chamber is connected to an external compressed air source via an air inlet installed on the air block. The air blowing pipe is inserted into the air block and communicates with the air chamber. The blowing end of the air blowing pipe faces the dicing stage.

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