Scribing machine and scribing method

Abstract

The invention provides a scribing machine and a scribing method.The scribing machine comprises a scribing table, a rack, a lifting driving mechanism, a lifting base, a scribing assembly and a thickness measuring camera, the scribing table is used for bearing 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 installed on the rack in a lifting and sliding mode and connected to a movable part of the lifting driving mechanism, the thickness measuring camera and the scribing assembly are arranged on the lifting seat side by side, and the lifting driving mechanism is used for driving the thickness measuring camera and the scribing assembly to ascend and descend; the thickness measuring camera is configured to measure the thickness of the wafer on the scribing table; the dicing assembly is configured to dice the wafer based on a thickness of the wafer. The scribing machine provided by the invention can perform automatic thickness measurement operation on the wafer on the scribing table, so that the scribing assembly can perform scribing operation on the wafer based on the thickness information of the wafer. The scribing cost is reduced, and the scribing efficiency is improved.

Description

Technical Field

[0001] The present application relates to the field of semiconductor device production, and in particular to a dicing machine and a dicing method. Background Art

[0002] The dicing process is an important process in the actual production of semiconductor devices. The dicing process is implemented by a dicing machine, which includes components such as a spindle, a cutter, and a dicing table. The dicing process of the dicing machine is that the spindle drives the high-speed rotating cutter to descend and contact the wafer on the dicing table, and the spindle then drives the cutter to move close to the wafer along a predetermined dicing path, thereby cutting the wafer into a number of grains with predetermined sizes.

[0003] In order to ensure that the cutter can cut through the wafer and prevent the cutter from contacting the bearing surface of the dicing table and causing damage to the cutter, the thickness of the wafer needs to be measured before dicing, and on this basis, the maximum cutting depth of the cutter on the wafer is determined to ensure that the cutter does not cut through the blue film adhering to the wafer while cutting through the wafer. For example, when the thickness of the blue film is 0.1mm, the maximum cutting depth can be set to the thickness of the wafer + 0.05mm.

[0004] The existing dicing machine cannot perform automatic thickness measurement on the wafer, so before dicing, the wafer needs to be measured by a special thickness measuring device, which will inevitably increase the dicing cost and reduce the dicing efficiency. Summary of the invention

[0005] In order to solve the above technical problems, the first aspect of the present application provides a dicing machine, which adopts the following technical solution:

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

[0007] The dicing table is used to carry the wafer to be diced, wherein the wafer is attached to the blue film;

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

[0009] The lifting seat is installed on the frame in a lifting and sliding manner and is connected to the movable part of the lifting drive mechanism. The thickness measuring camera and the dicing assembly are arranged side by side on the lifting seat. The lifting drive mechanism is used to drive the thickness measuring camera and the dicing assembly to lift.

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

[0011] The dicing assembly is configured to scribe the wafer based on a thickness of the wafer.

[0012] The dicing machine provided by the present application has a thickness measuring camera on its lifting seat that can be raised and lowered synchronously with the dicing assembly. Before the formal dicing is carried out, the thickness measuring camera can automatically measure the thickness of the wafer on the dicing table. This enables the dicing assembly to perform the dicing operation on the wafer based on the thickness information of the wafer. Compared with the existing dicing method of using a special thickness measuring device to measure the thickness of the wafer, the dicing machine of the present application reduces the dicing cost and improves the dicing efficiency.

[0013] In some embodiments, the dicing table is connected to a translation driving module, and the translation driving module is used to drive the dicing table to translate; or, the frame is connected to the translation driving module, and the translation driving module is used to drive the frame to translate.

[0014] By driving the dicing table to translate relative to the dicing assembly through the translation drive module, or by driving the dicing assembly to translate relative to the dicing table through the shift drive module, the dicing assembly can be made to cut into the wafer on the dicing table and dicing the wafer.

[0015] In some embodiments, adsorption holes for adsorbing the blue film are provided on the supporting surface of the dicing table, or an annular groove is provided on the peripheral side of the dicing table, and the dicing machine also includes an annular tension ring, which tightens the periphery of the blue film and fixes it in the groove.

[0016] Two methods of fixing the blue film are provided, both of which can determine the positioning of the blue film on the carrying surface of the dicing table, thereby achieving the positioning of the wafer and preventing the wafer from shifting during the dicing process.

[0017] In some embodiments, the lifting drive mechanism includes a screw motor, a screw and a nut, wherein the screw motor is fixedly mounted on a frame, the screw is arranged in a vertical direction, the upper end of the screw is connected to the driving end of the screw motor via a coupling, the lower end of the screw is rotatably connected to the frame, the nut is threaded on the screw, and the lifting seat is fixedly connected to the nut.

[0018] The lifting seat is driven by a screw rod module. After the lifting seat is lifted into place, it can stably maintain the current height without accidental lifting, thereby improving the thickness measurement accuracy of the thickness measuring camera and ensuring the dicing effect of the dicing assembly.

[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 the mounting seat, the spindle is installed at the lower end of the connecting seat, the cutter is vertically installed on the spindle, and the spindle is used to drive the cutter to rotate.

[0020] A dicing assembly with a simple structure is provided, which drives a cutting knife to rotate at high speed through a main shaft to implement dicing of a wafer.

[0021] In some embodiments, the dicing machine also 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 cavity is provided in the air block, the air cavity is connected to an external compressed air source via an air connector installed on the air block, the blowing pipe is plugged into the air block and connected to the air cavity; the blowing end of the blowing pipe faces the dicing table.

[0022] During the dicing process, the purge mechanism can promptly blow away the slag generated during the dicing process, further improving the dicing effect.

[0023] The present application also provides a dicing method, which is implemented by any of the dicing machines described above, and the dicing method comprises:

[0024] The lifting drive mechanism drives the thickness measuring camera to lift and lower, and the thickness measuring camera focuses on the scribing table during the lifting and lowering process to obtain a first focal length of the thickness measuring camera relative to the bearing surface of the scribing table;

[0025] Place the wafer on the carrying surface of the dicing table and attach the wafer to the blue film;

[0026] The lifting drive mechanism drives the thickness measuring camera to lift and lower, and the thickness measuring camera focuses on the wafer during the lifting and lowering process to obtain a second focal length of the thickness measuring camera relative to the upper surface of the wafer;

[0027] Calculating the thickness of the wafer based on the second focal length and the first focal length;

[0028] 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 scribe the wafer.

[0029] The dicing method provided in the present application can implement automatic thickness measurement of the wafer on the dicing table, so that the dicing component can perform dicing operations on the wafer based on the thickness information of the wafer, thereby reducing the dicing cost and improving the dicing efficiency.

[0030] In some optional embodiments, the lifting drive mechanism drives the thickness measuring camera to lift, and the thickness measuring camera focuses on the scribing table during the lifting process to obtain a first focal length of the thickness measuring camera relative to the bearing surface of the scribing table, 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, wherein when stepping to each height, the thickness measuring camera captures 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] determining a second focus range according to the clarity of the first image;

[0033] The lifting drive mechanism drives the thickness measuring camera to step up or step down within the second focus range according to the second step length, wherein when stepping to each height, the thickness measuring camera captures a second image of the dicing table and obtains the clarity of the second image, and synchronously controls the thickness measuring camera to step to the next height, wherein 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 according to the clarity of the second image.

[0035] First, a longer first step length is used to implement coarse focusing in the first focusing range to find the second focusing range including the optimal focusing position. Then a shorter second step length is used to implement fine focusing in the second focusing range to find the optimal focusing position of the thickness measuring camera relative to the dicing table, thereby obtaining a first focal length of the thickness measuring camera relative to the supporting surface of the dicing table.

[0036] In some optional embodiments, the lifting drive mechanism drives the thickness measuring camera to lift, and the thickness measuring camera focuses on the wafer during the lifting process 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, wherein when stepping to each height, the thickness measuring camera captures 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;

[0038] determining a second focus range according to the clarity of the first image;

[0039] The lifting drive mechanism drives the thickness measuring camera to step up or step down within the second focus range according to the second step length, wherein when stepping to each height, the thickness measuring camera captures a second image of the wafer and obtains the clarity of the second image, and synchronously controls the thickness measuring camera to step to the next height, wherein 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 according to the clarity of the second image.

[0041] First, a longer first step length is used to implement coarse focusing in the first focusing range to find the second focusing range including the optimal focusing position. Then a shorter second step length is used to implement fine focusing in the second focusing range 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 thickness of the wafer, and controls the dicing assembly to diced the wafer, including:

[0043] Determine the maximum cutting depth of the cutter on the wafer according to the thickness of the wafer, and obtain the radius of the cutter and the length of the target cutting groove;

[0044] Determine the initial feed speed of the cutter and the middle section scribing speed of the cutter, wherein the middle section scribing speed is greater than the initial feed speed;

[0045] Calculate the cutter's feed stroke based on the cutter radius and maximum cutting depth;

[0046] Calculate the middle stroke of the cutter based on the target grooving length and feed stroke;

[0047] Calculate the acceleration based on the initial feed speed, the mid-slice dicing speed and the feed stroke;

[0048] Control the cutter to cut into the wafer at an initial feed speed and acceleration;

[0049] Controlling the cutter to cut the wafer at the middle cutting speed until the cutting stroke of the cutter reaches the middle stroke;

[0050] The cutter is controlled to cut out the wafer at the mid-slicing speed and acceleration deceleration.

[0051] Use low speed for cutting at the beginning of cutting, then accelerate to high speed steadily, and use high speed and uniform speed for cutting after the force on the cutter is stable. When cutting, decelerate steadily from high speed to the initial cutting speed until the cutting is completed. In this way, the cutting efficiency can be ensured, and the quality of the slices can be taken into account, and the edge collapse can be prevented when the cutting is in and out. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a structural schematic diagram of a dicing machine in an embodiment of the present application;

[0053] Figure 2 for Figure 1 A schematic diagram of a partial structure of a dicing machine;

[0054] Figure 3 Schematic diagram of the dicing process of the cutting knife in the application embodiment.

[0055] Figures 1 to 3 Included:

[0056] Scribing table 1: groove 11, tension ring 12;

[0057] Rack 2;

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

[0059] Lifting seat 4;

[0060] Slicing assembly 5: connecting seat 51, spindle 52, cutter 53;

[0061] Thickness camera 6;

[0062] Purge mechanism 7: air block 71, air connection head 72, air blowing pipe 73;

[0063] Wafer 100 and blue film 200 . DETAILED DESCRIPTION

[0064] The technical solution of the present application will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0065] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0066] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

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

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

[0069] The dicing table 1 is used for carrying a wafer 100 to be diced, wherein the wafer 100 is attached to a blue film 200 .

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

[0071] The lifting seat 4 is installed on the frame 1 in a lifting and sliding manner and is connected to the movable part of the lifting drive mechanism 3. The thickness measuring camera 6 and the dicing assembly 5 are arranged side by side on the lifting seat 4. The lifting drive mechanism 4 is used to drive the thickness measuring camera 6 and the dicing assembly 5 to rise and fall synchronously.

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

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

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

[0075] Before placing the wafer 100 to be diced on the dicing table 1, first, the thickness measuring camera 6 is driven to rise and fall by the lifting drive mechanism 3. During the lifting process, the thickness measuring camera 6 performs a focusing operation on the dicing table 1 to determine the first focal length of the thickness measuring camera 6 relative to the dicing table 1, that is, Figure 2 As shown, the distance between the lens of the thickness measuring camera 6 and the supporting surface B of the dicing table 1 .

[0076] Subsequently, the wafer 100 adhered to the blue film 200 is placed on the dicing table 1. The thickness measuring camera 6 is then driven to rise and fall by the lifting drive mechanism 3. During the lifting process, the thickness measuring camera 6 performs a focusing operation on the wafer 100 to determine the second focal length of the thickness measuring camera 6 relative to the wafer 100, that is, Figure 2 As shown, the distance between the lens of the thickness measurement camera 6 and the upper surface A of the wafer 100 .

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

[0078] Optionally, the first focal length and the second focal length measured by the thickness measuring camera 6 can be obtained through a PLC connected to the signal of the thickness measuring camera 6 , and 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 scribes the wafer 100 based on the thickness of the wafer 100 , ensuring that the dicing assembly 5 does not touch the dicing stage 1 while dicing through the wafer 100 .

[0080] It can be seen that the dicing machine provided in the embodiment of the present application automatically measures the thickness of the wafer on the dicing table through a thickness measuring camera before the formal dicing is carried out. Thus, the dicing component can perform the dicing operation on the wafer based on the thickness information of the wafer. Compared with the existing dicing method of using a special thickness measuring device to measure the thickness of the wafer, the dicing machine in the embodiment of the present application reduces the dicing cost and improves the dicing efficiency.

[0081] In an optional embodiment, the dicing table 1 is connected to a 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 table 1 to translate toward the dicing assembly 5, so that the dicing assembly 5 cuts into the wafer 100 on the dicing table 1 and completes the dicing of the wafer 100.

[0082] In another optional embodiment, the frame 2 is connected to a 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 table 1 and complete the dicing of the wafer 100.

[0083] like Figure 2 As shown, optionally, an annular groove 11 is provided on the peripheral side of the dicing table 1. The dicing machine also includes an annular tension ring 12, which tightens and fixes the peripheral edge of the blue film 200 in the groove 11. In this way, it can be ensured that the blue film 200 is positioned on the bearing surface of the dicing table 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. Of course, adsorption holes can also be provided on the bearing surface of the dicing table 1, and the blue film is adsorbed and positioned on the bearing surface of the dicing table 1 by the adsorption holes.

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

[0085] The screw motor 31 drives the screw rod 32 to rotate, thereby driving the nut 33 to rise and fall smoothly along the screw rod 32, and finally driving the lifting seat 4 to rise and fall synchronously. The screw module composed of the screw motor 31, the screw rod 32 and the nut 33 is used to implement the lifting and lowering drive of the lifting seat 4. After the lifting and lowering of the lifting seat 4, it can be stably maintained at the current height, thereby preventing accidental lifting and lowering, thereby improving the thickness measurement accuracy of the thickness measuring camera 6, and preventing the scribing assembly 5 from shaking during the scribing process, thereby improving the scribing effect.

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

[0087] When the dicing table 1 and the dicing assembly 5 are relatively translated, 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 application concept, the present application provides a dicing method, which is implemented by a dicing machine provided by any of the above embodiments. The dicing method in the embodiment of the present application includes the following steps:

[0089] S1 . The lifting drive mechanism 3 drives the thickness measuring camera 6 to lift and lower. The thickness measuring camera 6 focuses on the dicing table 1 during the lifting and lowering process to obtain a first focal length of the thickness measuring camera 6 relative to the bearing surface of the dicing table 1 .

[0090] S2 , placing the wafer 100 on the table of the dicing table 1 , wherein the wafer 100 is attached to the blue film 200 .

[0091] S3 , the lifting drive mechanism 3 drives the thickness measuring camera 6 to lift and lower. The thickness measuring camera 6 focuses on the wafer 100 during the lifting and lowering process to obtain a 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 a target height based on the thickness of the wafer, and controls the dicing assembly to scribe the wafer.

[0094] The dicing method in the embodiment of the present application can perform automatic thickness measurement of the wafer on the dicing table before dicing, so that the dicing component can perform dicing operations on the wafer based on the thickness information of the wafer, thereby reducing the dicing cost and improving the 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 down within the first focusing range according to the first step length, wherein when stepping to each height, the thickness measuring camera 6 takes a first image of the dicing table 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 focus range may be the range within which the thickness measuring camera 6 can be raised and lowered. Of course, in order to narrow the first focus range, the approximate range of the best focus position may also be determined based on experience, and the range may be used as the first focus range.

[0098] For example, in a specific embodiment, the length of the first focus range in the vertical direction is 60 mm. The upper end point of the first focus range can be used as the stepping starting point, and the lower end point of the first focus range can be used as the stepping end point. The lifting drive mechanism 3 drives the thickness measuring camera 6 to step down from the stepping starting point toward the stepping end point according to the first step length of 3 mm. Of course, the lower end point of the first focus range can also be used as the stepping starting point, and the upper end point of the first focus range can be used as the stepping end point. The lifting drive mechanism 3 drives the thickness measuring camera 6 to step up from the stepping starting point toward the stepping end point according to the first step length of 3 mm.

[0099] Each time the lifting drive mechanism 3 drives the thickness measuring camera 6 to step to a height, the thickness measuring camera 6 takes a picture of the scribing table to obtain a first image of the scribing table 1. After the picture is taken, the thickness measuring camera 6 or the PLC connected to the thickness measuring camera 6 analyzes the first image to calculate the clarity of the first image. At the same time, the lifting drive mechanism 3 drives the thickness measuring camera 6 to step to the next height. In other words, the processing thread of the thickness measuring camera 6 acquiring the first image and calculating the clarity of the first image runs in parallel with the processing thread of the lifting drive mechanism 3 driving the thickness measuring camera 6 to step to the next height, thereby shortening the focusing time. After the stepping is completed, the thickness measuring camera 6 obtains 21 first images and obtains the clarity data corresponding to the 21 first images.

[0100] S12: Determine a second focus range according to the clarity of the first image.

[0101] Specifically, the height corresponding to the first image with the maximum definition is used as the center position of the second focusing range, and two adjacent heights corresponding to the height of the first image with the maximum definition are used as two end points of the second focusing range.

[0102] Still taking the above embodiment as an example, for example, among the 21 first images corresponding to 21 height points, the first image at the 10th height point has the maximum clarity. Then the second focus range finally determined is the range between the 9th height point and the 11th height point. The length of the second focus range in the vertical direction is 6 mm.

[0103] Of course, in order to improve the focusing accuracy, more first images can be obtained by shortening the first step length, thereby ultimately shortening the length of the first focusing range in the vertical direction.

[0104] S13, the lifting drive mechanism 3 drives the thickness measuring camera 6 to step up or down within the second focusing range according to the second step length, wherein when stepping to each height, the thickness measuring camera 6 takes a second image of the dicing table 1, and obtains the clarity of the second image, and synchronously controls the thickness measuring camera 6 to step to the next height, wherein 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] Still taking the above embodiment as an example, the second step length can be set to 1 mm. The thickness measuring camera 6 is driven by the lifting drive mechanism 3 to step down or up in the second focus range between the 9th height point and the 11th height point. Finally, 5 second images corresponding to the 5 height points are obtained, and the clarity of the 5 second images is obtained accordingly.

[0106] Similarly, in order to improve the focusing accuracy, a greater number of second images can be obtained by shortening the second step length.

[0107] S14. Determine a first focal length according to the clarity of the second image.

[0108] The height corresponding to the second image with the maximum definition is selected as the best focus position. The distance between the focus position and the bearing surface B of the dicing table 1 is the first focal length.

[0109] It can be seen that in the focusing process of step S1, firstly, a longer first step length is used to implement coarse focusing in the first focusing range to find the second focusing range including the best focusing position, and then a shorter second step length is used to implement fine focusing in the second focusing range to find the best focusing position of the thickness measuring camera relative to the scribing table, thereby obtaining the first focal length of the thickness measuring camera relative to the bearing surface of the scribing table. In this way, the first focal length of the thickness measuring camera relative to the bearing surface of the scribing table can be quickly and accurately acquired.

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

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

[0112] S32: Determine a second focus range according to the clarity of the first image.

[0113] S33, the lifting drive mechanism drives the thickness measuring camera to step up or down along the second step length within the second focusing range, wherein when stepping to each height, the thickness measuring camera captures a second image of the wafer, obtains the clarity of the second image, and synchronously controls the thickness measuring camera to step to the next height, wherein 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 a second focal length according to the clarity of the second image.

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

[0116] Similarly, in the focusing process of step S3, firstly, a longer first step length is used to implement coarse focusing in the first focusing range to find the second focusing range including the best focusing position, and then a shorter second step length is used to implement fine focusing in the second focusing range to find the best 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 quickly and accurately acquired.

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

[0118] As known to those skilled in the art, the resistances encountered by the cutter during the wafer dicing process are not the same. Specifically, the force applied to the cutter gradually increases during the process of cutting into the wafer. The force applied to the cutter gradually increases and decreases during the process of cutting out the wafer. However, the force applied to the cutter in the middle section of the wafer dicing (i.e., the section between the feed section and the exit section) remains unchanged. In the existing dicing method, the cutter uses a fixed dicing speed (i.e., the translational speed of the cutter relative to the wafer) during the entire dicing process. It is difficult to take into account both dicing efficiency and dicing quality at the same time. For example, if the dicing speed is set too high, it will cause chipping of the wafer during the feed or exit process. If the dicing speed is set too low, the dicing efficiency will be too low.

[0119] Therefore, it is possible to consider controlling the cutter to cut into or out of the wafer at a lower speed, and to implement the cutting of the middle section of the wafer at a higher speed. During the cutting process, as the cutter continues to cut in, the force on the cutter gradually increases, and the risk of wafer edge collapse gradually decreases. Therefore, it is possible to consider gradually increasing the cutting speed, so that after the cutting is completed, the speed of the cutter increases to a higher middle section cutting speed. During the cutting process, as the cutter continues to cut out, the force on the cutter gradually decreases, and the risk of wafer edge collapse gradually increases. Therefore, it is possible to consider gradually reducing the cutting speed.

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

[0121] S51 , determining the maximum cutting depth d of the wafer 100 by the cutter 53 according to the thickness of the wafer 100 , and obtaining the radius R of the cutter 53 and the target cutting groove length L.

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

[0123] S52, determining an initial feed speed V0 of the cutter 53 and a middle-segment scribing speed V of the cutter 53, wherein the middle-segment scribing speed V is greater than the initial feed speed V0.

[0124] The initial feed speed V0 and the middle dicing speed V are set according to the material and dicing requirements of the wafer 100 , and are generally empirical values ​​or obtained through experiments.

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

[0126] In addition, if Figure 3 As shown, at half of the feed stroke S, S / 2, the difference between the radius R of the cutter 53 and the maximum cutting depth d satisfies the Pythagorean theorem, that is: (S / 2) 2 =R 2 -(Rd) 2 , so we can get, S = 2√2Rd-d 2 .

[0127] S54, based on the target groove length L and the feed stroke S, calculate the middle stroke S1 of the cutter.

[0128] The middle stroke S1 = the length of the target groove L - the infeed stroke S - the outfeed stroke. Since the outfeed stroke is equal to the infeed stroke S, S1 = L-2S.

[0129] S55, calculate the acceleration a based on the initial feed speed V0, the middle dicing speed V and the feed stroke S.

[0130] Optionally, the acceleration a is set to a constant value, that is, the process of cutting in is a uniform acceleration process, and the process of cutting out is a uniform deceleration process. Then the acceleration a=(V 2 -V0 2 ) / 2S.

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

[0132] S57 , controlling the cutter 53 to cut the wafer 100 at the middle-stage cutting speed V until the cutting stroke of the cutter 53 reaches the middle-stage stroke S1 .

[0133] S58 , controlling the cutter 53 to decelerate and cut out the wafer 100 at the middle scribing speed V and the acceleration a.

[0134] Since the speed changes in the knife-exiting stage and the knife-feeding stage of step S55 are just opposite, the speed of the cutter 53 after leaving the wafer 100 just drops to the initial knife-feeding speed V0.

[0135] It can be seen that in the dicing process of step S5, a low speed is used at the beginning of the cutting, and then it is steadily accelerated to a high speed, and a high and uniform speed is used for cutting after the force of the cutter 53 is stabilized. When the cutter is removed, the high speed is steadily decelerated to the initial cutting speed until the cutting is completed, so that the cutting efficiency can be ensured, and the quality of the dicing can be taken into account, and the edge collapse caused by the cutting and the removal of the cutter can be prevented.

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

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

[0138] A reserved dicing stroke S0 is determined, and the cutter 53 is controlled to move toward the wafer 100 at a uniform speed at an initial feed speed V0 for the reserved dicing stroke S0 , so that the cutter 53 contacts the wafer 100 .

[0139] By setting the reserved dicing stroke S0 , it is possible to prevent the cutter 53 from directly going down onto the wafer 100 and causing impact damage to the cutter 53 . In addition, the blue film 200 supporting the wafer 100 can also be diced.

[0140] Similarly, optionally, after controlling the cutter 53 in step S58 to decelerate and cut out the wafer 100 at the middle dicing speed V and the acceleration a, step S5 further includes: controlling the cutter 53 to move away from the wafer 100 at the initial feed speed V0 to reserve a dicing stroke S0.

[0141] The present application is described in sufficient detail above with certain particularity. It should be understood by those skilled in the art that the description in the embodiments is merely exemplary, and all changes made without departing from the true spirit and scope of the present application should fall within the scope of protection of the present application. The scope of protection claimed in the present application is defined by the claims, rather than by the above description in the embodiments.

Claims

1. A dicing machine, characterized in that: The dicing machine comprises a dicing table, a frame, a lifting drive mechanism, a lifting seat, a dicing assembly and a thickness measuring camera, wherein: The dicing table is used to carry the wafer to be diced, wherein the wafer is attached to the blue film; The frame is arranged above the dicing table, and the lifting drive mechanism is arranged on the frame; The lifting seat is installed on the frame in a lifting and sliding manner and is connected to the movable part of the lifting drive mechanism. The thickness measuring camera and the dicing assembly are arranged side by side on the lifting seat. The lifting drive mechanism is used to drive the thickness measuring camera and the dicing assembly to lift and lower. The thickness measuring camera is configured to measure the thickness of the wafer located on the dicing table; The dicing assembly is configured to scribe the wafer based on a thickness of the wafer.

2. The dicing machine according to claim 1, characterized in that: The scribing table is connected to a translation driving module, and the translation driving module is used to drive the scribing table to translate; or, The frame is connected to a translation driving module, and the translation driving module is used to drive the frame to translate.

3. The dicing machine according to claim 1, characterized in that: The carrying surface of the dicing table is provided with adsorption holes for adsorbing the blue film, or; An annular groove is arranged on the peripheral side of the dicing table, and the dicing machine further comprises an annular tension ring, which tightens and fixes the peripheral edge of the blue film in the groove.

4. The dicing machine according to claim 1, characterized in that: The lifting drive mechanism includes a screw motor, a screw and a nut, wherein the screw motor is fixedly mounted on the frame, the screw is arranged in a vertical direction, the upper end of the screw is connected to the driving end of the screw motor via a coupling, the lower end of the screw is rotatably connected to the frame, the nut is screwed on the screw, and the lifting seat is fixedly connected to the nut.

5. The dicing machine according to claim 1, wherein: The dicing assembly includes a connecting seat, a main shaft and a cutter, wherein the upper end of the connecting seat is connected to the mounting seat, the main shaft is installed at the lower end of the connecting seat, the cutter is vertically installed on the main shaft, and the main shaft is used to drive the cutter to rotate.

6. The dicing machine according to claim 1, wherein: The dicing machine further comprises a purge mechanism, which comprises an air block and an air blow pipe, wherein: The gas block is connected to the bottom of the camera, an air cavity is provided in the gas block, the air cavity is connected to an external compressed air source via an air connector installed on the gas block, and the air blowing pipe is plugged into the gas block and communicated with the air cavity; The blowing end of the blowing pipe faces the dicing table.

7. A dicing method, characterized in that: The dicing method is implemented by the dicing machine according to any one of claims 1 to 6, and the dicing method comprises: The lifting drive mechanism drives the thickness measuring camera to lift and lower, and the thickness measuring camera focuses on the scribing table during the lifting and lowering process to obtain a first focal length of the thickness measuring camera relative to the bearing surface of the scribing table; Placing a wafer on the carrying surface of the dicing table, wherein the wafer is attached to the blue film; The lifting drive mechanism drives the thickness measuring camera to lift and lower, and the thickness measuring camera focuses on the wafer during the lifting and lowering process to obtain a second focal length of the thickness measuring camera relative to the upper surface of the wafer; Calculating the thickness of the wafer 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 scribe the wafer.

8. The dicing method according to claim 7, wherein: It is characterized in that The lifting drive mechanism drives the thickness measuring camera to lift, and the thickness measuring camera focuses on the scribing table during the lifting process to obtain a first focal length of the thickness measuring camera relative to the bearing surface of the scribing table, including: The lifting drive mechanism drives the thickness measuring camera to step up or step down within the first focus range according to the first step length, wherein when stepping to each height, the thickness measuring camera captures 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; determining a second focus range according to the clarity of the first image; The lifting drive mechanism drives the thickness measuring camera to step up or step down within the second focus range according to the second step length, wherein when stepping to each height, the thickness measuring camera captures a second image of the dicing table, obtains the clarity of the second image, and synchronously controls the thickness measuring camera to step to the next height, wherein 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 according to the clarity of the second image.

9. The dicing method according to claim 7, wherein: It is characterized in that The lifting drive mechanism drives the thickness measuring camera to lift and lower, and the thickness measuring camera focuses on the wafer during the lifting and lowering process 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, wherein when stepping to each height, the thickness measuring camera captures a first image of the wafer, obtains the clarity of the first image, and synchronously controls the thickness measuring camera to step to the next height; determining a second focus range according to the clarity 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, wherein when stepping to each height, the thickness measuring camera captures a second image of the wafer and obtains the clarity of the second image, and synchronously controls the thickness measuring camera to step to the next height, wherein 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 according to the clarity of the second image.

10. The dicing method according to claim 7, wherein: The dicing method is implemented by the dicing machine in claim 5, wherein 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 dicing the wafer, including: Determine the maximum cutting depth of the wafer by the cutter according to the thickness of the wafer, and obtain the radius of the cutter and the length of the target cutting groove; Determining an initial feed speed of the cutter and a middle-segment scribing speed of the cutter, wherein the middle-segment scribing speed is greater than the initial feed speed; Calculating the feed stroke of the cutter based on the cutter radius and the maximum cutting depth; Calculating the middle stroke of the cutter based on the target groove length and the feed stroke; Calculating acceleration based on the initial feed speed, the middle scribing speed and the feed stroke; Controlling the cutter to cut into the wafer at the initial feed speed and the acceleration; Controlling the cutter to cut the wafer at the middle-stage cutting speed until the cutting stroke of the cutter reaches the middle-stage stroke; The cutting blade is controlled to cut out the wafer at a mid-slicing speed and the acceleration deceleration.

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