Wafer laser cutting machine and heterogeneous integrated wafer process parameter optimization method

Abstract

The invention provides a wafer laser cutting machine and a heterogeneous integrated wafer process parameter optimization method, and belongs to the technical field of laser cutting equipment.The wafer laser cutting machine comprises a cutting platform, an industrial personal computer and a laser device, the cutting platform is provided with a Y-direction linear motor, the Y-direction linear motor is provided with a clamp used for clamping a wafer, and the Y-direction linear motor is connected with the industrial personal computer; vertical columns are arranged on the two sides of the Y-direction linear motor, the vertical columns are arranged on the cutting platform, an X-direction linear motor is arranged on the vertical columns, a Z-direction linear motor is arranged on the X-direction linear motor, a laser cutting head is arranged on the Z-direction linear motor, and the laser cutting head is electrically connected with a laser device. A light source adopted by the laser cutting head is infrared light with the wavelength of 1080 nm, and the X-direction linear motor, the Y-direction linear motor and the Z-direction linear motor are electrically connected with the industrial personal computer. Compared with a traditional laser cutting machine, the wafer laser cutting machine has the advantage that the machining efficiency is improved on the basis of keeping high-precision machining.

Description

Technical Field

[0001] The present invention relates to the technical field of laser cutting equipment, and particularly relates to a wafer laser cutting machine and a method for optimizing process parameters of heterogeneous integrated wafers. Background Art

[0002] With the rapid development of industries such as intelligent manufacturing, automotive electronics, artificial intelligence, 5G communication, and the Internet of Things, as the core hardware of these industries, the market scale and technical level of integrated circuits are constantly improving. As a type of integrated circuit, chip manufacturing has also become one of the rapidly developing industries.

[0003] Wafer cutting is a key process in chip manufacturing, and its technical precision and efficiency directly affect the performance and cost of chips. With the rapid development of semiconductor devices towards miniaturization and high integration, traditional mechanical blade cutting technology is gradually facing bottlenecks: mechanical stress is likely to cause wafer chipping or microcracks, especially for ultra-thin wafers (thickness less than 100 μm) or hard and brittle materials (such as SiC), and the processing yield is relatively low. Compared with mechanical cutting, the core of laser cutting lies in using a high-energy laser beam to precisely cut semiconductor wafers (such as silicon, silicon carbide, gallium nitride, etc.) to achieve chip separation or structured processing. Laser cutting mainly uses ultraviolet (UV) or ultrafast pulsed lasers to remove materials through photothermal or photochemical effects. Short wavelengths (such as 355 nm ultraviolet laser) can achieve smaller focused spots (micrometer level), and ultra-short pulses (<10 ps) trigger non-linear absorption inside the material through extremely high peak power, significantly reducing the heat-affected zone (HAZ) and avoiding thermal stress damage. In addition, laser cutting technology avoids the influence of mechanical stress on the wafer through non-contact processing and high-precision energy control, reducing the generation of cracks and fragments.

[0004] However, the current development of laser cutting technology still needs to break through the following bottlenecks: 1. There is a contradiction between the processing precision and processing efficiency of wafers. High-precision cutting requires sacrificing the cutting speed; 2. The process parameters during heterogeneous integrated wafer processing need to be optimized. For this reason, we propose a wafer laser cutting machine and a method for optimizing process parameters of heterogeneous integrated wafers. Summary of the Invention

[0005] The present invention provides a wafer laser cutting machine and a method for optimizing process parameters of heterogeneous integrated wafers to solve the problems existing in the above background art.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention provides a wafer laser cutting machine, which includes a cutting platform, an industrial control computer, and a laser. A Y-direction linear motor is arranged on the cutting platform. A fixture for clamping a wafer is arranged on the Y-direction linear motor. Columns are arranged on both sides of the Y-direction linear motor. The columns are arranged on the cutting platform. An X-direction linear motor is arranged on the columns. A Z-direction linear motor is arranged on the X-direction linear motor. A laser cutting head is arranged on the Z-direction linear motor. The laser cutting head is electrically connected to the laser. The light source adopted by the laser cutting head is infrared light with a wavelength of 1080 nm. The X-direction linear motor, the Y-direction linear motor, and the Z-direction linear motor are all electrically connected to the industrial control computer.

[0008] Further, the fixture includes a cross beam, which is slidably arranged on a slide rail. The slide rail is arranged on a fixed seat. The fixed seat is arranged on the Y-direction linear motor.

[0009] Further, a plurality of grooves for fixing the wafer are arranged on the cross beam. Rubber gaskets are arranged at the edges of the grooves.

[0010] Further, the fixed seat includes a storage box. A groove box is arranged at the top of the storage box. The slide rail is arranged on the side of the groove box away from the storage box.

[0011] Further, a plurality of grooves are formed on the groove box. The grooves penetrate through the groove box and are connected to the inner cavity of the storage box. Stainless steel domes are arranged at the tops of some of the grooves. The diameter of the stainless steel domes is larger than the diameter of the grooves.

[0012] Further, the stroke of the X-direction linear motor is 0 - 300 mm, the positioning accuracy is ±0.003 mm, and the repeat positioning accuracy is ±0.001 mm. The stroke of the Y-direction linear motor is 0 - 300 mm, the positioning accuracy is ±0.003 mm, and the repeat positioning accuracy is ±0.001 mm. The stroke of the Z-direction linear motor is 0 - 300 mm, the positioning accuracy is ±0.02 mm, and the repeat positioning accuracy is ±0.01 mm.

[0013] The present invention also provides a method for optimizing process parameters of a heterogeneous integrated wafer. The method uses the above-mentioned wafer laser cutting machine and includes the following steps:

[0014] S1: Set the laser parameters of the laser, the motion parameters of the laser cutting head, and the motion parameters of the fixture according to the material characteristics of the heterogeneous integrated wafer; the laser parameters of the laser include wavelength, power, and pulse width, the motion parameters of the laser cutting head include cutting speed, cutting path, and focusing height, and the motion parameters of the fixture include moving speed;

[0015] S2: Design a multi-factor experiment to screen parameter combinations;

[0016] S3: Simulate the temperature field distribution, heat affected zone, and stress concentration area of the heterogeneous integrated wafer under different parameter combinations in step S2 through the simulation model;

[0017] S4: Perform trial cutting on the heterogeneous integrated wafer under different parameter combinations in step S2. If the trial cutting result does not meet the cutting quality evaluation index, then combine the trial cutting data and simulation data, and repeat steps S2 - S4 to optimize the parameters until the cutting quality evaluation index is satisfied; if the trial cutting result meets the cutting quality evaluation index, then perform formal cutting on the heterogeneous integrated wafer.

[0018] Further, in step S2, the Taguchi method and response surface method are used to design experiments to screen parameter combinations.

[0019] Further, in step S4, the cutting quality evaluation index includes surface quality, cutting efficiency, and heat affected zone. The surface quality includes chipping width and crack depth. The chipping width is less than 20 μm, the crack depth is less than 1 μm, the cutting efficiency is that the cutting time per unit length is less than 1 minute per wafer, and the range of the heat affected zone is less than 5 μm.

[0020] Compared with the prior art, the present invention has the following technical effects:

[0021] 1. In the present invention, this wafer laser cutting machine is provided with an X-axis linear motor, a Y-axis linear motor, and a Z-axis linear motor. The three linear motors of the X-axis linear motor, Y-axis linear motor, and Z-axis linear motor work independently of each other, which can reduce the failure rate and increase the service life. The industrial control computer controls the movement of the three linear motors in their respective directions. The industrial control computer adjusts the position of the laser cutting head by controlling the X-axis linear motor and the Z-axis linear motor, and the industrial control computer adjusts the position of the fixture by controlling the Y-axis linear motor. Through the cooperation of the X-axis linear motor, Y-axis linear motor, Z-axis linear motor, and industrial control computer, the positioning accuracy and cutting accuracy of the laser cutting head and the fixture can be quickly achieved, greatly improving the cutting efficiency of the wafer; in addition, the laser cutting head uses infrared light with a wavelength of 1080 nm to cut the wafer. Compared with traditional laser cutting machines, when cutting wafers of the same size, the time can be shortened from several minutes to within one minute, further improving the cutting efficiency.

[0022] 2. In the present invention, the crossbeam can move along the slide rail, enabling the fixture to clamp wafers of different sizes, so that the laser cutting head can cut wafers of different sizes. When the fixture clamps the wafer through the card slot, a rubber pad is provided at the edge of the card slot, which can increase the contact area between the fixture and the wafer, reduce stress concentration, and prevent damage to the wafer.

[0023] 3. In the present invention, a plurality of grooves are provided on the groove box. The grooves penetrate through the groove box and are connected to the inner cavity of the storage box. Stainless steel domes are provided on some of the grooves, and no stainless steel domes are provided on the remaining grooves. The stainless steel domes support the wafers to prevent them from falling. During cutting, the scrap fragments smaller than the diameter of the grooves fall into the storage box through the grooves for centralized processing.

[0024] 4. The method for optimizing the process parameters of heterogeneous integrated wafers provided by the present invention dynamically matches the laser parameters, motion parameters and material characteristics, realizes parameter linkage, and significantly improves the processing efficiency and consistency of heterogeneous integrated wafers. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The drawings described herein are used to provide a further understanding of the present application and form a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation of the present application. In the drawings:

[0026] Figure 1 is a schematic diagram of the overall structure of the wafer laser cutting machine according to an embodiment of the present invention Figure 1 ;

[0027] Figure 2 is a schematic diagram of the overall structure of the wafer laser cutting machine according to an embodiment of the present invention Figure 2 ;

[0028] Figure 3 is a schematic diagram of the structures of the industrial control computer and the laser according to an embodiment of the present invention;

[0029] Figure 4 is a schematic diagram of the structure of the cutting platform according to an embodiment of the present invention;

[0030] Figure 5 is a schematic diagram of the structure of the fixture according to an embodiment of the present invention;

[0031] Figure 6 is a schematic diagram of the structure of the groove box according to an embodiment of the present invention;

[0032] Figure 7 is a schematic diagram of the crossbeam picking up the wafer according to an embodiment of the present invention.

[0033] In the figure: 1. Cutting platform, 2. Column, 3. Laser cutting head, 4. Fixture, 41. Crossbeam, 42. Card slot, 5. Y-direction linear motor, 6. Z-direction linear motor, 7. X-direction linear motor, 8. Industrial control computer, 9. Laser, 10. Bolt, 11. Slide rail, 12. Fixed seat, 121. Storage box, 122. Groove box, 123. Groove, 124. Stainless steel dome, 13. Wafer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0035] In this article, terms such as "left, right, up, down, front, back" are established based on the positional relationship shown in the accompanying drawings. Depending on the different accompanying drawings, the corresponding positional relationship may also change accordingly. Therefore, it cannot be understood as an absolute limitation of the protection scope.

[0036] Please refer to Figures 1 to 7 , this embodiment provides a wafer laser cutting machine, including a cutting platform 1, an industrial control computer 8, and a laser 9. A Y-axis linear motor 5 is fixedly installed on the cutting platform 1. A fixture 4 is fixedly provided on the Y-axis linear motor 5. The fixture 4 is used to clamp the wafer 13 so that the laser cutting head 3 can cut the wafer 13. The slider on the Y-axis linear motor 5 can drive the fixture 4 to reciprocate along the Y-axis.

[0037] Specifically, a column 2 is provided on each side of the Y-axis linear motor 5. The two columns 2 are fixedly arranged on the cutting platform 1. The column 2 is made of marble. An X-axis linear motor 7 is fixedly installed on the two columns 2. A Z-axis linear motor 6 is fixedly installed on the X-axis linear motor 7. The laser cutting head 3 is fixedly installed on the Z-axis linear motor 6 through a bolt 10. The slider on the X-axis linear motor 7 can drive the Z-axis linear motor 6 to reciprocate along the X-axis. The slider on the Z-axis linear motor 6 can drive the laser cutting head 3 to reciprocate along the Z-axis. The laser cutting head 3 is electrically connected to the laser 9. The type of collimation of the laser 9 is 100 mm, and the focusing is 125 mm. The laser 9 can emit infrared light with a wavelength of 1080 nm. In this embodiment, the light source adopted by the laser cutting head 3 is the infrared light with a wavelength of 1080 nm emitted by the laser 9. Compared with cutting with yellow-green light, using infrared light with a wavelength of 1080 nm can reach the best cutting threshold in a short time, and higher-efficiency cutting can be achieved by adjusting the pulse width of the laser 9. Compared with traditional laser cutting machines, when cutting wafers 13 of the same size, the time can be shortened from several minutes to less than one minute.

[0038] Specifically, the X-axis linear motor 7, the Y-axis linear motor 5, and the Z-axis linear motor 6 are all electrically connected to the industrial control computer 8. The X-axis linear motor 7, the Y-axis linear motor 5, and the Z-axis linear motor 6 work independently of each other. The industrial control computer 8 can control the X-axis linear motor 7, the Y-axis linear motor 5, and the Z-axis linear motor 6 to move along their respective directions. The industrial control computer 8 adjusts the position of the laser cutting head 3 by controlling the movements of the X-axis linear motor 7 and the Z-axis linear motor 6, and the industrial control computer 8 adjusts the position of the fixture 4 (i.e., the position of the wafer 13) by controlling the movement of the Y-axis linear motor 5. In this embodiment, the stroke of the X-axis linear motor 7 is 0 - 300 mm, the maximum stroke is 300 mm, the positioning accuracy is ±0.003 mm, and the repeat positioning accuracy is ±0.001 mm; the stroke of the Y-axis linear motor 5 is 0 - 300 mm, the maximum stroke is 300 mm, the positioning accuracy is ±0.003 mm, and the repeat positioning accuracy is ±0.001 mm; the stroke of the Z-axis linear motor 6 is 0 - 300 mm, the maximum stroke is 300 mm, the positioning accuracy is ±0.02 mm, and the repeat positioning accuracy is ±0.01 mm.

[0039] Specifically, this wafer laser cutting machine is provided with an X-axis linear motor 7, a Y-axis linear motor 5, and a Z-axis linear motor 6. The three linear motors work independently of each other, which can reduce the failure rate and increase the service life. The industrial control computer 8 controls the movements of the three linear motors in their respective directions. The industrial control computer 8 adjusts the position of the laser cutting head 3 by controlling the X-axis linear motor 7 and the Z-axis linear motor 6, and the industrial control computer 8 adjusts the position of the fixture 4 by controlling the Y-axis linear motor 5. Through the cooperation of the X-axis linear motor 7, the Y-axis linear motor 5, the Z-axis linear motor 6, and the industrial control computer 8, the positioning accuracy and cutting accuracy of the laser cutting head 3 and the fixture 4 can be quickly achieved, greatly improving the cutting efficiency of the wafer 13; in addition, the laser cutting head 3 uses infrared light with a wavelength of 1080 nm to cut the wafer 13. Compared with traditional laser cutting machines, when cutting wafers 13 of the same size, the time can be shortened from several minutes to less than one minute, further improving the cutting efficiency.

[0040] Specifically, the fixture 4 includes two cross beams 41 arranged opposite to each other. The two cross beams 41 are slidably arranged on the slide rail 11. The slide rail 11 is a high-precision linear guide rail with a coating on its surface to prevent wear. The slide rail 11 is fixedly arranged at the edge of the top of the groove box 122 of the fixed seat 12, and the setting direction (i.e., the length direction of the slide rail 11) is the X-axis direction. The cross beam 41 can freely slide back and forth on the slide rail 11. By moving the cross beam 41, the size of the fixed area of the wafer 13 can be adjusted to adapt to wafers 13 of different sizes, such as 4 inches, 6 inches, 8 inches, etc. In this way, the fixture 4 can clamp wafers 13 of different sizes, and the laser cutting head 3 can thus cut wafers 13 of different sizes.

[0041] Specifically, there are two driving methods for the cross beam 41 to move on the slide rail 11, one is manual and the other is electric. In the manual method, the staff needs to add a slide rail locking mechanism, and a common slide rail locking mechanism can be used, which will not be elaborated here in detail. During operation, the staff loosens the slide rail locking mechanism and manually pushes the cross beam 41 to the target position and then locks it again. In the electric method, the cross beam 41 is driven to move on the slide rail 11 by a stepper motor or a servo motor, and then controlled by the industrial control computer 8 to achieve automatic adjustment, and the corresponding driving structure can be conventional, which will not be elaborated here in detail.

[0042] Specifically, a number of card slots 42 are fixedly installed on the opposite sides of the two cross beams 41. The card slots 42 are evenly arranged and are used to fix the wafer 13. A rubber gasket is also provided at the edge of the card slot 42. When the fixture 4 clamps the wafer 13, the rubber gasket can increase the contact area between the fixture 4 and the wafer 13, reduce stress concentration, avoid microcracks or breakage of the wafer 13 due to external forces during the cutting process, and prevent unnecessary damage and destruction of the wafer 13.

[0043] Specifically, the fixed seat 12 is fixedly arranged on the Y-direction linear motor 5. The fixed seat 12 includes a storage box 121 with an open top. A groove box 122 is fixedly provided at the top of the storage box 121. A number of grooves 123 are opened on the groove box 122. The grooves 123 penetrate through the groove box 122 and are connected to the inner cavity of the storage box 121. Stainless steel domes 124 are provided at the tops of some of the grooves 123, that is, an appropriate amount of stainless steel domes 124 are placed on the grooves 123 below the cutting position of the wafer 13. The diameter of the stainless steel dome 124 is larger than the diameter of the groove 123. The stainless steel dome 124 can support the wafer 13. When the cutting of the wafer 13 is completed, the cutting area and the edge of the wafer 13 are separated, and the stainless steel dome 124 supports the wafer 13 to prevent the wafer 13 from falling and breaking. During the entire cutting process of the wafer 13, after each cutting is completed, the large corner pieces larger than the diameter of the groove 123 will fall on the top of the groove box 122, and these large corner pieces need to be manually cleaned; the small corner pieces smaller than the diameter of the groove 123 will fall into the storage box 121 through the grooves 123 without the stainless steel domes 124 for centralized processing.

[0044] Specifically, each component of this wafer laser cutting machine is detachably installed, especially the storage box 121 is detachably installed. When the storage box 121 has been used for a period of time, the staff removes the storage box 121, which is convenient for cleaning the storage box 121.

[0045] This embodiment also provides a method for optimizing the process parameters of a heterogeneous integrated wafer. Taking the Si / GaN heterogeneous integrated wafer as an example, this method uses the wafer laser cutting machine described above and includes the following steps:

[0046] S1: According to the material characteristics of the Si / GaN heterogeneous integrated wafer, set the laser parameters of the laser 9, the motion parameters of the laser cutting head 3, and the motion parameters of the fixture 4 on the industrial control computer 8. The laser parameters of the laser 9 include wavelength, power, and pulse width. The motion parameters of the laser cutting head 3 include cutting speed, cutting path, and focusing height. The motion parameters of the fixture 4 include moving speed.

[0047] S2: Use the Taguchi method to design a multi-factor orthogonal experiment to screen the key parameter combinations, and then perform fine optimization using the response surface method.

[0048] S3: For the Si / GaN heterogeneous integrated wafer, use simulation software to perform hierarchical modeling, and simulate the temperature field distribution, heat affected zone (HAZ), and stress concentration area of the heterogeneous integrated wafer under different parameter combinations in step S2 through the simulation model to exclude high-risk parameter combinations, that is, parameter combinations that do not meet the cutting quality evaluation indicators.

[0049] S4: Perform trial cutting on the heterogeneous integrated wafers under different parameter combinations in step S2, analyze the cutting appearance and composition changes through SEM / EDS, then count the yield (yield greater than 99%), and record the defect types (such as chipping, microcracks, and interlayer delamination). If the trial cutting results do not meet the cutting quality evaluation indicators, combine the trial cutting data and simulation data, and repeat steps S2 - S4 to optimize the parameters until the cutting quality evaluation indicators are met, and then perform formal cutting on the Si / GaN heterogeneous integrated wafer; if the trial cutting results meet the cutting quality evaluation indicators, perform formal cutting on the heterogeneous integrated wafer.

[0050] Specifically, the cutting quality evaluation indicators include surface quality, cutting efficiency, and heat affected zone. The surface quality includes chipping width and crack depth. The chipping width is less than 20 μm, the crack depth is less than 1 μm, the cutting efficiency is that the cutting time per unit length is less than 1 minute per wafer, and the range of the heat affected zone is less than 5 μm.

[0051] Specifically, in this embodiment, for the process parameters optimized for the Si / GaN heterogeneous integrated wafer, a hierarchical parameter strategy is adopted for cutting the Si layer and the GaN layer. For the Si layer, high power (40 W), low speed (5 mm / s), and deep focus (the Z-axis linear motor 6 drives the laser cutting head 3 to move downward) are used for cutting; for the GaN layer, low power (25 W), high speed (10 mm / s), and shallow focus (the Z-axis linear motor 6 drives the laser cutting head 3 to move upward) are used for cutting. Also, 1080 nm infrared laser is used, combined with picosecond-level pulses (<10 ps) and intermittent emission strategy to ensure that the material dissipates heat sufficiently during the pulse interval, and the heat-affected zone (HAZ) is controlled within 3 μm (the traditional nanosecond laser HAZ > 10 μm). Furthermore, in the heterogeneous interface region (Si / GaN junction), gradient power or speed reduction cutting is adopted to avoid delamination caused by stress concentration.

[0052] Specifically, the mapping relationship between the material characteristics and process parameters of the wafer 13 established during the optimization process of the process parameter optimization method for this heterogeneous integrated wafer can be used to establish a material-process database on this basis. When cutting a new type of heterogeneous integrated wafer (such as gallium oxide), the database can recommend initial values based on similar material parameters, and this wafer laser cutting machine supports one-key calling, thus shortening the R & D cycle.

[0053] Specifically, this process parameter optimization method dynamically matches the laser parameters, motion parameters, and material characteristics, and realizes real-time collaborative adjustment and parameter linkage through the industrial control computer 8, significantly improving the processing efficiency and consistency of the heterogeneous integrated wafer.

[0054] The above embodiments only illustrate the basic principles and characteristics of the present invention, but are not limited by the above embodiments. It should be understood that for those of ordinary skill in the art, various changes and modifications can be made to the present invention without departing from the spirit and scope of the present invention, and these changes and modifications all fall within the scope of the present invention claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A wafer laser cutting machine, characterized in that: The invention comprises a cutting platform (1), an industrial computer (8) and a laser (9), wherein a Y-direction linear motor (5) is arranged on the cutting platform (1), a fixture (4) for clamping a wafer (13) is arranged on the Y-direction linear motor (5), columns (2) are arranged on both sides of the Y-direction linear motor (5), the columns (2) are arranged on the cutting platform (1), an X-direction linear motor (7) is arranged on the columns (2), a Z-direction linear motor (6) is arranged on the X-direction linear motor (7), a laser cutting head (3) is arranged on the Z-direction linear motor (6), the laser cutting head (3) is electrically connected to the laser (9), the light source used by the laser cutting head (3) is infrared light with a wavelength of 1080 nm, and the X-direction linear motor (7), the Y-direction linear motor (5) and the Z-direction linear motor (6) are all electrically connected to the industrial computer (8).

2. The wafer laser cutting machine according to claim 1, characterized in that: The clamp (4) comprises a crossbeam (41), the crossbeam (41) is slidably arranged on a slide rail (11), the slide rail (11) is arranged on a fixed seat (12), and the fixed seat (12) is arranged on a Y-axis linear motor (5).

3. The wafer laser cutting machine according to claim 2, characterized in that: The crossbeam (41) is provided with a plurality of slots (42) for fixing the wafer (13), and rubber gaskets are provided at the edges of the slots (42).

4. The wafer laser cutting machine according to claim 2, characterized in that: The fixing seat (12) comprises a storage box (121), a groove box (122) is provided at the top end of the storage box (121), and the slide rail (11) is arranged on a side of the groove box (122) away from the storage box (121).

5. The wafer laser cutting machine according to claim 4, characterized in that: The groove box (122) is provided with a plurality of grooves (123), the grooves (123) penetrate the groove box (122) and are connected with the inner cavity of the storage box (121), and the tops of some of the grooves (123) are provided with stainless steel domes (124), and the diameter of the stainless steel domes (124) is greater than the diameter of the grooves (123).

6. The wafer laser cutting machine according to claim 1, characterized in that: The stroke of the X-axis linear motor (7) is 0-300 mm, the positioning accuracy is ±0.003 mm, and the repeat positioning accuracy is ±0.001 mm. The stroke of the Y-axis linear motor (5) is 0-300 mm, the positioning accuracy is ±0.003 mm, and the repeat positioning accuracy is ±0.001 mm. The stroke of the Z-axis linear motor (6) is 0-300 mm, the positioning accuracy is ±0.02 mm, and the repeat positioning accuracy is ±0.01 mm.

7. A method for optimizing process parameters of heterogeneous integrated wafers, the method using a wafer laser cutting machine as described in any one of claims 1 to 6, characterized in that: The following steps are involved: S1: setting the laser parameters of the laser (9), the motion parameters of the laser cutting head (3) and the motion parameters of the fixture (4) according to the material properties of the heterogeneous integrated wafer; the laser parameters of the laser (9) include wavelength, power and pulse width, the motion parameters of the laser cutting head (3) include cutting speed, cutting path and focusing height, and the motion parameters of the fixture (4) include moving speed; S2: Design multi-factor experiments to screen parameter combinations; S3: simulating the temperature field distribution, heat affected zone and stress concentration area of ​​the heterogeneous integrated wafer under different parameter combinations in step S2 through a simulation model; S4: Perform trial cutting on the heterogeneous integrated wafer under different parameter combinations in step S2. If the trial cutting result does not meet the cutting quality evaluation index, combine the trial cutting data and simulation data, repeat steps S2-S4 to optimize the parameters until the cutting quality evaluation index is met; if the trial cutting result meets the cutting quality evaluation index, formally cut the heterogeneous integrated wafer.

8. The heterogeneous integrated wafer process parameter optimization method according to claim 7, characterized in that: In step S2, Taguchi method and response surface methodology are used to design experiments to screen parameter combinations.

9. The heterogeneous integrated wafer process parameter optimization method according to claim 7, characterized in that: In step S4, the cutting quality evaluation indexes include surface quality, cutting efficiency and heat-affected zone. The surface quality includes chipping width and crack depth. The chipping width is less than 20 μm, the crack depth is less than 1 μm, the cutting efficiency is the cutting time per unit length is less than 1 minute / piece, and the range of the heat-affected zone is less than 5 μm.

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