A multi-beam intelligent focusing laser stealth cutting device for wafer cutting

Abstract

The application relates to the technical field of wafer cutting, in particular to a multi-beam intelligent focusing laser invisible cutting device for wafer cutting. The device comprises a rack, a driving module fixedly arranged on the rack, a first driving part and a second driving part of the driving module, a limiting fixing module arranged on the first driving part, a limiting fixing frame of the limiting fixing module capable of supporting and limiting a wafer, a cutting module arranged on the second driving part, at least two laser generators capable of relatively sliding and adjusting of the cutting module and an adjusting unit capable of precisely adjusting the interval between the two laser generators, and a focusing module coaxially arranged at a laser output end of the laser generator. The device can not only realize high cutting efficiency, but also can self-adjust the cutting light beam and the cutting height according to the cutting requirement.

Description

Technical Field

[0001] This invention relates to the field of wafer dicing technology, specifically to a multi-beam intelligent focusing laser stealth dicing device for wafer dicing. Background Technology

[0002] As semiconductor wafers, sapphire crystals, silicon carbide wafers, and other brittle crystalline materials develop towards larger sizes and higher integration, the requirements for processing efficiency, modification precision, and cutting stability in traditional crystal dicing processes are constantly increasing. Existing wafer stealth dicing processes typically use laser focusing to form a modification layer inside the crystal, followed by a subsequent crack propagation process to achieve material separation. Because this processing method can reduce surface chipping and the heat-affected zone, it is widely used in the processing of semiconductor wafers and brittle crystalline materials.

[0003] In existing technologies, most laser stealth cutting equipment adopts a single laser head line-by-line scanning cutting method, using a single laser beam to sequentially modify the interior of the crystal along a preset cutting path. However, when cutting large-size wafers or large-format crystals, the single laser head needs to scan back and forth area by area, resulting in a long processing path and a significant increase in the overall cutting cycle, making it difficult to meet the requirements of high-efficiency continuous production. Especially when performing high-density cutting on high-hardness crystal materials, long-term continuous processing with a single laser beam can easily lead to local heat accumulation, thereby affecting the consistency of the modified layer and the cutting stability.

[0004] In addition, although some existing laser cutting equipment can improve the single-shot coverage by using beam expansion structures, the laser energy distribution after beam expansion is prone to dispersion or offset, resulting in inconsistent energy density between multiple cutting areas, which in turn affects the continuity of the modified layer inside the crystal. At the same time, most traditional beam expansion structures only achieve laser beam splitting and lack the ability to guide and control the expanded laser beam in a single column. This makes it easy for multiple laser beams to have problems such as optical path offset, focus misalignment and cutting trajectory error during transmission, reducing the accuracy of multi-beam synchronous cutting.

[0005] On the other hand, in the process of stealth crystal cutting, different thicknesses of crystals and different cutting depths usually correspond to different modified layer heights. However, the focusing structures in existing equipment mostly adopt fixed focal lengths or single-layer focusing methods, which make it difficult to adjust the laser modified layer height in real time according to changes in crystal thickness and internal cutting requirements. When the focal position does not match the preset modified layer height, it is easy to cause insufficient modified layer depth or over-focusing, resulting in uneven internal crack propagation, cutting section offset, and local breakage, which further affects the cutting yield. Especially when it is necessary to form a multi-layer modified zone in one process, the traditional single-focus cutting method usually requires multiple repeated scans, which not only has low processing efficiency, but also easily leads to the accumulation of thermal stress inside the crystal due to repeated processing. Summary of the Invention

[0006] To address the aforementioned issues, a multi-beam intelligent focusing laser stealth cutting device for wafer dicing is provided. This device not only enables multi-laser cutting but also provides single-column guidance and transmission of the expanded laser beam and dynamically adjusts the laser focus height according to the internal modification requirements of the crystal. This solves the technical problems of low efficiency in single-head laser cutting, insufficient stability of multi-beam laser guidance, and difficulty in achieving one-time forming and cutting of different modification layers in the prior art.

[0007] To address the problems of existing technologies, this invention provides a multi-beam intelligent focusing laser stealth dicing device for wafer dicing, comprising: a frame; a drive module fixedly mounted on the frame, the drive module having a first drive component and a second drive component; a restraining module mounted on the first drive component, the restraining module having a restraining frame capable of supporting and limiting the wafer; and a dicing module mounted on the second drive component, the dicing module having at least two laser generators capable of relative sliding adjustment and an adjustment unit capable of precisely adjusting the distance between the two laser generators to achieve synchronous adaptation of different dicing spacings and dicing areas. A focusing module is coaxially mounted at the laser output end of the laser generator. The focusing module includes a beam expanding unit for expanding the laser beam, a guiding unit for guiding the expanded laser beam in a single column, and a focusing unit for independently adjusting the focal position of each single laser beam. The beam expanding unit expands the laser output from the laser generator into multiple laser beams. The guiding unit guides the expanded laser beams in a single column, ensuring they are arranged in a preset single column configuration. The focusing unit independently adjusts the focal position of different single laser beams according to the wafer thickness and the height of the modified layer.

[0008] Preferably, the adjustment unit is provided with a guide frame capable of guiding the two laser generators to move horizontally towards each other, a drive frame capable of driving the two laser generators to move towards each other, and a third drive component capable of synchronously transmitting the driving force to the laser generators; the third drive component is fixedly disposed on the top of the laser generator and is connected to the guide frame in a transmission manner.

[0009] Preferably, the drive frame is a V-shaped frame with a sliding groove inside for the third drive member to slide; the middle part of the drive frame is also provided with a limiting part protruding into the sliding groove, which is used to limit and block the third drive member after it slides to the middle part of the drive frame.

[0010] Preferably, the cutting module further includes a linear driver capable of self-adjusting the longitudinal cutting height of the laser generator; the adjustment unit is fixedly mounted on the first driving member via the linear driver; the adjustment unit is fixedly mounted vertically at the driving end of the linear driver.

[0011] Preferably, the focusing module further includes a straightening unit capable of collimating the expanded laser beam; the beam expanding unit, guiding unit, straightening unit and focusing unit are coaxially fixedly arranged at the laser emitting end of the laser generator in sequence.

[0012] Preferably, the guiding unit includes a guiding chamber, a blocking plate capable of blocking the laser, and a guiding hole that passes through the blocking plate to guide the laser in a single line; the blocking plate is detachably disposed in the guiding chamber; and the guiding hole passes through the blocking plate.

[0013] Preferably, the drive module further includes a first coordinate robot and a second coordinate robot capable of driving the first drive member and the second drive member to move in multiple directions respectively; the first drive member and the second drive member are respectively fixedly disposed on the drive ends of the first coordinate robot and the second coordinate robot.

[0014] Preferably, the retaining frame is an adsorption plate used to automatically hold the wafer to be cut.

[0015] The advantages of this invention compared to the prior art are: 1. This invention sets up two relatively adjustable laser generators and uses an adjustment unit to achieve synchronous cutting of the two laser generators. This enables synchronous quality modification cutting of two regions while ensuring wafer cutting accuracy. Compared with the traditional single laser head pass-by-pass processing method, it effectively shortens the overall cutting cycle of large wafers and improves wafer batch processing efficiency.

[0016] 2. This invention, through the coordinated operation of the beam expansion unit, the guiding unit, the straightening unit, and the focusing unit, can expand a single laser beam into multiple beams arranged in a row, and perform single-column guidance and independent focus adjustment on the expanded laser beam, so that multiple beams can act on different height regions inside the wafer, thereby achieving the effect of forming multiple modified layers in one cut, avoiding the problem of repeated focusing and layer processing required in traditional stealth cutting, and improving processing efficiency and modification consistency. Attached Figure Description

[0017] Figure 1 This is a 3D view of a multi-beam intelligent focusing laser stealth dicing device for wafer cutting.

[0018] Figure 2This is a partial structural side view of the drive module and the cutting module in a multi-beam intelligent focusing laser stealth cutting device for wafer dicing.

[0019] Figure 3 yes Figure 2 Sectional view at point AA.

[0020] Figure 4 This is a partial three-dimensional structure of the cutting module and focusing module in a multi-beam intelligent focusing laser stealth dicing device for wafer dicing. Figure 1 .

[0021] Figure 5 This is a partial three-dimensional structure of the cutting module and focusing module in a multi-beam intelligent focusing laser stealth dicing device for wafer dicing. Figure 2 .

[0022] Figure 6 yes Figure 5 A magnified view of section B.

[0023] Figure 7 This is a three-dimensional view showing the partial structural hierarchy of the cutting module and focusing module in a multi-beam intelligent focusing laser stealth cutting device for wafer dicing.

[0024] Figure 8 This is an exploded perspective view of the focusing module in a multi-beam intelligent focusing laser stealth dicing device used for wafer cutting.

[0025] The numbers on the map are: 1. Rack; 2. Drive module; 21. First drive component; 22. Second drive component; 3. Fixture module; 31. Fixture frame; 4. Cutting module; 41. Laser generator; 42. Adjustment unit; 421. Guide frame; 422. Drive frame; 423. Third drive component; 424. Electric push rod; 425. Fixing frame; 426. Limiting part; 427. Slide groove; 43. Linear actuator; 5. Focusing module; 51. Beam expander unit; 52. Guide unit; 521. Guide chamber; 522. Barrier plate; 523. Guide hole; 53. Focusing unit; 54. Straightening unit. Detailed Implementation

[0026] To further understand the features, technical means, and specific objectives and functions achieved by the present invention, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

[0027] See Figures 1 to 8The following is illustrated: A multi-beam intelligent focusing laser stealth dicing device for wafer dicing includes a frame 1; a drive module 2, fixedly mounted on the frame 1, the drive module 2 having a first drive element 21 and a second drive element 22; a restraining module 3, mounted on the first drive element 21, the restraining module 3 having a restraining frame 31 capable of supporting and limiting the wafer; a dicing module 4, mounted on the second drive element 22, the dicing module 4 having at least two laser generators 41 capable of relative sliding adjustment and an adjustment unit 42 capable of precisely adjusting the distance between the two laser generators 41 to achieve synchronous adaptation of different dicing spacings and dicing areas; and a focusing module 5. The focusing module 5 is coaxially disposed at the laser output end of the laser generator 41. It includes a beam expanding unit 51 for expanding the laser beam, a guiding unit 52 for guiding the expanded laser beam in a single column, and a focusing unit 53 for independently adjusting the focal position of the single column laser beam. The beam expanding unit 51 can expand the laser output from the laser generator 41 into multiple laser beams. The guiding unit 52 is used to guide the expanded laser beams in a single column, so that the multiple laser beams are exported in a preset single column arrangement. The focusing unit 53 can independently adjust the focusing position of different single column laser beams according to the wafer thickness and the height of the modified layer.

[0028] When stealth dicing of a wafer is required, the wafer to be diced is first placed on the retaining frame 31, and the retaining frame 31 positions and retains the wafer to prevent the dicing accuracy from being affected by vibration, displacement, or uneven local stress during the dicing process. Then, the focusing module 5 is activated, so that the laser output from the laser generator 41 passes through beam expansion, single-row guidance, and focus adjustment processes in sequence. Among them, the laser beam expanded can form multiple parallel light paths, which are then guided by the guiding unit 52 to be led out in a preset arrangement. The focusing unit 53 independently adjusts the focusing depth of different beams, so that multiple laser focal points can be focused separately. Corresponding to different heights of the modified layer regions inside the wafer; after completing the optical path adjustment, the adjustment unit 42 is driven to operate, and the relative distance between the two laser generators 41 is precisely adjusted so that the laser cutting areas on both sides are adapted to the current wafer cutting width, cutting track spacing and modified area requirements; finally, the driving module 2 is driven to operate, the first driving element 21 drives the fixing module 3 to move along the preset direction, and the second driving element 22 synchronously drives the cutting module 4 to move along the corresponding cutting trajectory, so that the wafer and the multi-beam laser form a relative displacement, thereby synchronously forming multiple sets of modified layers of different heights inside the wafer, until the stealth cutting process of the wafer is completed.

[0029] By combining multi-beam synchronous cutting with multi-layer synchronous refining, the wafer cutting efficiency can be improved while ensuring the accuracy of refining layer formation and cutting stability.

[0030] See Figures 5 to 7 As shown: The adjustment unit 42 is provided with a guide frame 421 that can guide the two laser generators 41 to move horizontally towards each other, a drive frame 422 that can drive the two laser generators 41 to move towards each other, and a third drive member 423 that can synchronously transmit the driving force to the laser generators 41; the third drive member 423 is fixedly disposed on the top of the laser generators 41 and is connected to the guide frame 421 in a transmission manner.

[0031] The adjustment unit 42 further includes an electric push rod 424 for precisely sliding the drive frame 422 in the longitudinal direction, and a fixing frame 425 for vertically mounting the electric push rod 424 on the guide frame 421. When it is necessary to adjust the distance between the two laser generators 41 according to different wafer sizes, dicing widths, or dicing area requirements, an external power supply is first connected to drive the electric push rod 424. During the extension and retraction process, the output shaft of the electric push rod 424 synchronously drives the drive frame 422 to slide longitudinally in a preset direction, and the driving force is stably transmitted to the corresponding laser generator 41 through the third drive component 423, so that... Two laser generators 41 can move closer or further apart synchronously in opposite directions. During adjustment, the two laser generators 41 always maintain the relative alignment of their corresponding optical path centerlines, thereby ensuring the spacing accuracy between the cutting areas. At the same time, since the two laser generators 41 can perform cutting operations synchronously, the overall processing time of a single wafer can be effectively shortened and the processing efficiency of large-size wafers can be improved while ensuring the consistency of the cutting path. The two laser generators 41 are respectively set on both sides of the drive frame 422 and form a sliding fit with the guide frame 421 through the third drive component 423 set on the top, so as to ensure the stable guiding effect of the laser generators 41 during the adjustment process.

[0032] See Figures 5 to 7 As shown: The drive frame 422 is specifically a V-shaped frame with a sliding groove 427 inside for the third drive member 423 to slide; the middle part of the drive frame 422 is also provided with a limiting part 426 protruding into the sliding groove 427, the limiting part 426 is used to limit and block the third drive member 423 after it slides to the middle part of the drive frame 422.

[0033] The V-shaped drive frame 422 ensures that the two laser generators 41 move synchronously along a symmetrical trajectory during relative sliding adjustment, thus preventing the center distance between the two laser generators 41 from shifting due to unilateral displacement errors. Specifically, when the third drive member 423 slides on the drive frame 422, the V-shaped structure provides synchronous guiding constraints for the two laser generators 41, ensuring they maintain symmetrical movement as they approach or move away, thereby guaranteeing the consistency of the spacing between the two cutting areas. Furthermore, the limiting part 426 located in the middle of the drive frame 422 blocks and limits the movement of the two third drive members 423 after they slide to the preset zero position, enabling the two laser generators 41 to achieve synchronous parallel positioning in the reset state. This provides a unified benchmark for subsequent cutting parameter calibration, focus correction, and cutting path initialization, preventing a decrease in cutting accuracy due to accumulated errors during long-term operation.

[0034] See Figure 2 As shown: The cutting module 4 further includes a linear driver 43 capable of self-adjusting the longitudinal cutting height of the laser generator 41; the adjustment unit 42 is fixedly mounted on the first driving member 21 via the linear driver 43; the adjustment unit 42 is fixedly mounted vertically on the driving end of the linear driver 43.

[0035] The linear actuator 43 allows for vertical height adjustment of the adjustment unit 42 and the laser generator 41, enabling precise adaptation of the relative distance between the laser output and the wafer to different wafer thicknesses, modification depths, and focusing requirements. When adjusting the laser focusing depth, simply driving the linear actuator 43 moves the adjustment unit 42 and the laser generator 41 synchronously in the vertical direction, thereby changing the spatial distance between the laser focus and the wafer and ensuring that the laser focus can stably act on the preset modification layer position inside the wafer. Simultaneously, since the adjustment unit 42 and the laser generator 41 adopt an integrated linkage lifting method, relative height errors between multiple laser beams can be avoided during the adjustment process, further ensuring the consistency of multi-beam cutting.

[0036] See Figure 3 As shown: The focusing module 5 also includes a straightening unit 54 capable of collimating the expanded laser beam; the beam expanding unit 51, the guiding unit 52, the straightening unit 54 and the focusing unit 53 are coaxially fixedly arranged at the laser emitting end of the laser generator 41.

[0037] By sequentially and coaxially arranging a beam expanding unit 51, a guiding unit 52, a straightening unit 54, and a focusing unit 53, continuous optical path processing of the laser output from the laser generator 41 can be achieved. Specifically, the beam expanding unit 51 expands the original laser into a multi-beam arrangement to increase the coverage of a single cut; the guiding unit 52 directionally limits the expanded beams, ensuring that the multiple laser beams are stably output in a preset single-column manner; the straightening unit 54 corrects the direction of the expanded beams, maintaining parallel output of each laser beam and avoiding positional errors in the modified layer due to optical path offset; and the focusing unit 53 independently adjusts the focusing depth of different beams, allowing each beam to act on different height positions within the wafer, thereby achieving the effect of forming a multi-layer modified structure in a single cut.

[0038] The beam expanding unit 51 is preferably composed of existing mature Galilean beam expanding lens group, Keplerian beam expanding lens group, or cylindrical beam expanding lens group; the straightening unit 54 is preferably composed of existing mature collimating lens group, reflection correction lens group, cylindrical correction lens group, or DOE diffraction optical correction component; the focusing unit 53 is preferably composed of existing mature dynamic focusing lens group, motorized zoom lens group, liquid lens focusing component, or MEMS micro-adjustment focusing component. The aforementioned beam expanding unit 51, beam straightening unit 54, and focusing unit 53 are all existing mature optical structures. Their specific configuration is not limited to the above-mentioned structural types. As long as they can realize the functions of laser beam expanding, beam direction correction, and focus depth adjustment, they are sufficient. Through the coaxial cooperation between the above-mentioned multiple optical units, it is possible to realize the formation of synchronous modification layers in different height regions inside the wafer by multi-beam laser, thereby improving the wafer stealth dicing efficiency and multi-layer dicing accuracy.

[0039] See Figure 8 As shown: The guiding unit 52 is provided with a guiding chamber 521, a blocking plate 522 that can block the laser, and a guiding hole 523 that is opened through the blocking plate 522 to guide the laser to pass through in a single row; the blocking plate 522 is detachably disposed in the guiding chamber 521; the guiding hole 523 is opened through the blocking plate 522.

[0040] When the laser beam, after being expanded by the beam expander unit 51, irradiates the surface of the barrier plate 522 in a rectangular array, in order to ensure that the expanded laser beam can be stably output in a preset single-column manner, the barrier plate 522 set in the guide unit 52 and the guide hole 523 opened on the barrier plate 522 can physically block the excess beam, allowing only the corresponding single-column beam to pass through the guide hole 523 to continue transmission, thereby achieving directional restriction on the laser arrangement. Since the position of the guide hole 523 corresponds to the required cutting trajectory, it can ensure that the final output beam arrangement meets the single-column cutting requirements and avoid excess beams interfering with non-cutting areas. In addition, when it is necessary to perform large-area matrix synchronous cutting of the wafer, it is only necessary to remove or move the guide unit 52 to release the restriction of the expanded beam by the barrier plate 522, so that the expanded matrix beam can be exported as a whole, thereby realizing multi-area synchronous cutting processing.

[0041] See Figure 1 and Figure 2 As shown: The drive module 2 further includes a first coordinate robot and a second coordinate robot capable of driving the first drive member 21 and the second drive member 22 to move in multiple directions respectively; the first drive member 21 and the second drive member 22 are respectively fixedly disposed on the drive ends of the first coordinate robot and the second coordinate robot.

[0042] Both the first and second coordinate robots are existing motion control devices, used to drive the first drive component 21 and the second drive component 22 to perform multi-axis linkage movement according to a preset program. During the cutting process, the first coordinate robot can drive the restraint module 3 to move the wafer in a plane according to the preset cutting trajectory, while the second coordinate robot synchronously drives the cutting module 4 to adjust the corresponding position, so that the wafer and the laser cutting path form a precise relative motion, thereby realizing the automated continuous cutting of the wafer. At the same time, after the preset cutting data is input into the control system, the cutting speed, cutting trajectory, cutting spacing and cutting layer height can be automatically controlled, reducing the degree of manual intervention and improving the consistency of processing.

[0043] See Figure 1 As shown: The retaining frame 31 is specifically an adsorption plate, used to automatically hold the wafer to be cut.

[0044] The retaining frame 31 is not limited to an adsorption disk structure. It can also adopt a vacuum adsorption structure, a mechanical clamping structure, or other limiting structures that can achieve stable fixation of the wafer according to actual processing needs, as long as it can form a stable retaining effect on the wafer during the cutting process. By setting the retaining frame 31, the cutting trajectory deviation caused by vibration, offset, or local force changes during high-speed cutting can be avoided, thereby ensuring the consistency between the laser modified layer and the preset cutting path.

[0045] This invention not only has high cutting efficiency, but also can automatically adjust the cutting beam and cutting height according to cutting requirements.

[0046] The above embodiments only illustrate one or more implementations of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the appended claims.

Claims

1. A multi-beam intelligent focusing laser stealth dicing device for wafer cutting, characterized in that, frame; A drive module is fixedly mounted on the frame, and the drive module is provided with a first drive component and a second drive component; A clamping module is disposed on the first driving component, and the clamping module is provided with a clamping frame capable of supporting and limiting the wafer. A cutting module is mounted on the second driving component. The cutting module is equipped with at least two laser generators that can be adjusted relative to each other and an adjustment unit that can precisely adjust the distance between the two laser generators to achieve synchronous adaptation of different cutting distances and cutting areas. The focusing module is coaxially mounted on the laser output end of the laser generator. The focusing module is equipped with a beam expanding unit that can expand the laser beam, a guiding unit for single-column limiting and guiding of the expanded laser beam, and a focusing unit for independently adjusting the focal position of a single-column laser beam. The beam expanding unit expands the laser output from the laser generator into multiple laser beams. The guiding unit limits and guides the expanded laser beams, so that they are exported in a preset single-column arrangement. The focusing unit can independently adjust the focusing position of different single-column laser beams according to the wafer thickness and the height of the modified layer.

2. The multi-beam intelligent focusing laser stealth dicing device for wafer dicing according to claim 1, characterized in that, The adjustment unit is provided with a guide frame that can guide the two laser generators to move horizontally towards each other, a drive frame that can drive the two laser generators to move towards each other, and a third drive component that can synchronously transmit the driving force to the laser generators. The third driving component is fixedly mounted on the top of the laser generator and is connected to the guide frame via a transmission connection.

3. The multi-beam intelligent focusing laser stealth dicing device for wafer dicing according to claim 2, characterized in that, The drive frame is specifically a V-shaped frame with a sliding groove inside for the third drive component to slide. The drive frame is also provided with a limiting part protruding into the slide groove in the middle, which is used to limit and block the third drive member after it slides to the middle of the drive frame.

4. The multi-beam intelligent focusing laser stealth dicing device for wafer dicing according to claim 1, characterized in that, The cutting module also includes a linear driver capable of self-adjusting the longitudinal cutting height of the laser generator; The adjustment unit is fixedly mounted on the first driving member via the linear driver; The adjustment unit is fixedly mounted vertically at the drive end of the linear actuator.

5. A multi-beam intelligent focusing laser stealth dicing device for wafer dicing according to claim 1, characterized in that, The focusing module also includes a straightening unit capable of collimating the expanded laser beam; The beam expander, guide, straightener, and focusing unit are sequentially and coaxially fixedly mounted on the laser emitting end of the laser generator.

6. The multi-beam intelligent focusing laser stealth dicing device for wafer dicing according to claim 5, characterized in that, The guiding unit is equipped with a guiding chamber, a blocking plate that can block the laser, and a guiding hole that is opened through the blocking plate to guide the laser to pass through in a single row. The barrier plate is detachably installed inside the guide compartment; The guide hole is formed through the barrier plate.

7. A multi-beam intelligent focusing laser stealth dicing device for wafer dicing according to claim 1, characterized in that, The drive module further includes a first coordinate robot and a second coordinate robot capable of driving the first drive component and the second drive component to move in multiple directions, respectively. The first driving component and the second driving component are respectively fixedly disposed on the driving end of the first coordinate robot and the second coordinate robot.

8. A multi-beam intelligent focusing laser stealth dicing device for wafer dicing according to claim 1, characterized in that, The clamping frame is specifically an adsorption plate used to automatically clamp the wafer to be cut.

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