Laser cutting method and apparatus based on silicon carbide wafers

Abstract

The application discloses a kind of laser cutting method and equipment based on silicon carbide wafer, method includes S100: the silicon carbide wafer of back surface is placed to the transparent suction disc of laser table cutting platform with good cutting film, glue is evenly applied to the entire wafer back surface;S200: the silicon carbide wafer is placed to the transparent suction disc of laser table cutting platform and generates first cutting path;S300: first laser is focused on the metal layer on the back surface of silicon carbide wafer, along the first cutting path, the metal layer on the back surface of wafer is completely removed to form V groove;S400: the silicon carbide wafer is re-applied to film and generates second cutting path;S500: second laser is focused on the inside of silicon carbide wafer, along the second cutting path, laser modification cutting is carried out in each cutting path, and the separation of a chip is realized by using splitting knife to press on cutting path.The method of the application utilizes the cutting effect of different lasers, solves the phenomenon of back metal tearing and front edge collapse, and poor straightness in the current cutting means.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of semiconductor processing, and more particularly relates to a laser cutting method and device based on a silicon carbide wafer. BACKGROUND

[0002] A silicon carbide wafer, also known as a silicon carbide single wafer, is a sheet-shaped single crystal material obtained by cutting, grinding, and polishing a silicon carbide crystal along a specific crystal direction. Laser cutting is a method that uses a focused high-power density laser beam to irradiate a workpiece, causing the irradiated material to rapidly melt, vaporize, ablate, or reach ignition, while a high-speed airflow coaxial with the beam is used to blow away the molten material, thereby achieving cutting of the workpiece. Since multiple line cutting and laser stripping techniques are used to cut the silicon carbide wafer, the existing technology cuts the silicon carbide ingot into multiple silicon carbide columns by laser cutting, and then cuts the silicon carbide columns one by one. In the existing technology, when cutting the silicon carbide wafer, the silicon carbide ingot needs to be cut into multiple silicon carbide columns by laser cutting, which generates excess loss during the cutting into columns. Moreover, when cutting one by one, the bonding glass carrier plate and debonding need to be performed once each time, and high-temperature separation and subsequent cooling are required for separation, resulting in large loss during cutting of the silicon carbide wafer, small number of obtained cuttings, complex process, and high processing cost.

[0003] To solve the above problems, patent document CN115555732A discloses a silicon carbide wafer cutting method that converges parallel laser beams into a conical laser beam, uses the conical laser beam tip focal point to modify the cutting inside the silicon carbide wafer, and then splits it into silicon carbide wafer blocks by expanding the thin film on the outer surface of the silicon carbide wafer. However, this method still has two problems. First, the silicon carbide wafer mentioned in the patent should be a structureless silicon carbide wafer. Since the silicon carbide wafer has high thermal conductivity and hardness, it is actually impossible to achieve effective separation by using laser modification cutting and expanding the film. Mechanical external force must be used to separate it. Second, for silicon carbide wafers with metal layers on the back, this method cannot solve the problem of tearing and sticking of the metal layer after cutting. Therefore, the present application can effectively solve the above problems and achieve high-quality separation of the silicon carbide wafer.

[0004] Furthermore, patent document CN116038143A discloses a silicon carbide wafer dicing process. This process utilizes plasma cutting to form dicing channels on the wafer surface; laser invisibility dicing is performed on the bottom surface of the dicing channels, destroying the metal deposition on the bottom surface of the dicing channels and the wafer; the wafer is then bonded to a dicing mold frame, the blockage is cut off, and the carrier board is removed; the dicing channels are partially broken by film expansion and dicing, thus achieving wafer dicing. This patent, after forming the dicing channels through plasma cutting, results in a large surface roughness. When using laser invisibility dicing, the laser cannot be focused inside the wafer, therefore, effective invisibility dicing cannot be achieved. Additionally, this method alters the process of depositing metal coatings on the front-end surface. Summary of the Invention

[0005] To address the issues of back metal layer tearing, front edge chipping, and poor straightness after laser cutting of silicon carbide wafers, this invention provides a laser cutting method and equipment based on silicon carbide wafers. It employs ultraviolet lasers and infrared lasers to cut the back metal layer and front non-metal layer of the silicon carbide wafer, respectively. By utilizing the cutting effects of different lasers, it solves the problems of back metal layer tearing, front edge chipping, and poor straightness that occur in current cutting methods.

[0006] To achieve the above objectives, according to a first aspect of the present invention, a laser cutting method based on a silicon carbide wafer is provided, comprising:

[0007] S100: Place the silicon carbide wafer with the back side facing up and the cutting film attached on the adhesive coating and cleaning platform, then drop water-soluble adhesive on the center of the back side of the wafer, and use the rotating platform to evenly coat the entire back side of the wafer with adhesive.

[0008] S200: After the glue dries, place the silicon carbide wafer on the transparent chuck of the laser surface cutting platform. Use the first CCD vision imaging to identify and locate the cutting path on the front of the silicon carbide wafer and generate the first cutting path.

[0009] S300: The first laser is focused on the back metal layer of the silicon carbide wafer. Along the first cutting path, the repetition rate, power and platform scanning speed of the laser are adjusted to completely remove the back metal layer of the wafer and form a V-groove.

[0010] S400: After the cutting is completed, the silicon carbide wafer is placed on the adhesive cleaning platform. The water-soluble adhesive is rinsed off with pure water, and the silicon carbide wafer is re-coated to ensure that the front side is facing up. The silicon carbide wafer is then placed on the microporous ceramic chuck of the laser hidden cutting platform. The second CCD vision imaging is used to identify and locate the cutting track position on the front side of the silicon carbide wafer and generate the second cutting path.

[0011] S500: the second laser is focused inside the silicon carbide wafer, along the second cutting path, the process parameters such as the repetition frequency, power and platform scanning speed, cutting times of the laser are regulated, laser modification cutting is carried out in each cutting path, and the protective film is covered on the front surface of the cut silicon carbide wafer, the chip separation is realized by pressing the cleaver on the cutting path.

[0012] Further, the front surface of the silicon carbide wafer is a structure layer, and the inner part of the cutting path is covered with a metal layer.

[0013] Further, the back surface of the silicon carbide wafer is fully covered with a metal layer with a thickness less than or equal to 5μm.

[0014] Further, in step S100, the silicon carbide wafer is carried by the iron ring and attached to the cutting film.

[0015] Further, in step S100, the rotation speed of the glue washing platform is 100r / min-3000r / min.

[0016] Further, in step S100, the volume of the glue is determined according to the size of the silicon carbide wafer and the viscosity of the glue, and is 5ml-15ml.

[0017] Further, in step S300, the depth of the V groove is less than the thickness of the metal layer on the back surface of the silicon carbide wafer, and the width is less than the width of the cutting path.

[0018] Further, in step S300, the first laser is an ultraviolet laser with a wavelength of 355nm, and the power fluctuation range is less than 0.1W.

[0019] Further, in step S500, the second laser is an infrared laser with a wavelength of 1064nm, and the power fluctuation range is less than 0.01W.

[0020] Further, the cutting position deviation of the first laser and the second laser on the silicon carbide wafer is not more than ±5μm.

[0021] Further, in step S500, the width of the cutting path is not less than 20μm.

[0022] Further, the width of the blade of the cleaver is not higher than 20μm.

[0023] According to the second aspect of the present application, a laser cutting device based on a silicon carbide wafer is provided, comprising:

[0024] The film attaching and glue applying mechanism is used to place the silicon carbide wafer with the back surface upward and the cutting film attached on the glue washing platform, then drop water-soluble glue at the center of the wafer back surface, and evenly apply the glue on the entire wafer back surface by rotating the platform;

[0025] A first cutting path planning mechanism is configured to place the silicon carbide wafer on a transparent chuck of a laser surface cutting platform, identify and locate the front cutting path of the silicon carbide wafer by using a first CCD vision imaging, and generate a first cutting path.

[0026] A first cutting mechanism is configured to emit a first laser to focus on the back metal layer of the silicon carbide wafer, control the repetition frequency, power and platform scanning speed process parameters of the laser along the first cutting path, completely remove the back metal layer of the wafer, and form a V-shaped groove.

[0027] A second cutting path planning mechanism is configured to place the silicon carbide wafer on a glue coating and cleaning platform, wash the water-soluble glue clean by using pure water, re-paste the film of the silicon carbide wafer to ensure that the front is upward, place the silicon carbide wafer on a microporous ceramic chuck of a laser hidden cutting platform, identify and locate the front cutting path of the silicon carbide wafer by using a second CCD vision imaging, and generate a second cutting path.

[0028] A second cutting mechanism is configured to emit a second laser to focus on the inside of the silicon carbide wafer, control the repetition frequency, power, platform scanning speed, cutting times and other process parameters of the laser along the second cutting path, perform laser modification cutting in each cutting path, cover the protective film on the front of the cut silicon carbide wafer, and realize the separation of each chip by pressing the cutting knife on the cutting path.

[0029] Further, the film pasting and glue coating mechanism includes a glue coating and cleaning platform chuck, an iron ring, a cutting film and a glue coating head.

[0030] The front cutting path of the silicon carbide wafer is downward, the back metal layer is upward, the cutting film is pasted through the iron ring, the silicon carbide wafer with the pasted film is adsorbed on the glue coating and cleaning platform chuck by negative pressure, the glue coating head is moved to the center of the silicon carbide wafer, the water-soluble glue is dropped, and then the glue coating and cleaning platform chuck is rotated to ensure that the glue is evenly coated on the surface of the silicon carbide wafer.

[0031] Further, the first cutting path planning mechanism includes a transparent chuck and a first CCD. The silicon carbide wafer is adsorbed on the transparent chuck by negative pressure, the position of the cutting path on the wafer is identified by the first CCD, and a first cutting path is generated.

[0032] Further, the first cutting mechanism includes a first laser and a laser surface cutting platform.

[0033] Further, the second cutting path planning mechanism includes a cleaning head, a microporous ceramic chuck, a second CCD and a laser hidden cutting platform.

[0034] Further, the second cutting mechanism comprises a second laser, a cleaver, a supporting platform and a protective film.

[0035] Overall, compared with the prior art, the above technical solutions conceived by the present application can achieve the following beneficial effects:

[0036] 1. The method of the present application uses ultraviolet laser and infrared laser to cut the metal layer on the back surface and the non-metal layer on the front surface of the silicon carbide wafer respectively, and solves the phenomena of tearing of the back metal layer and collapse of the front surface, and poor straightness in the current cutting methods by using the cutting effects of different lasers.

[0037] 2. The method of the present application focuses the first laser on the metal layer on the back surface of the silicon carbide wafer, forms a V groove along the first cutting path by adjusting the repetition frequency, power and platform scanning speed process parameters of the laser, and realizes the cutting of the metal layer on the back surface of the silicon carbide wafer.

[0038] 3. The method of the present application focuses the second laser on the inside of the silicon carbide wafer, adjusts the repetition frequency, power, platform scanning speed and cutting times of the laser along the second cutting path, performs laser modification cutting in each cutting path, covers a protective film on the front surface of the cut silicon carbide wafer, and realizes the cutting of the non-metal layer on the front surface of the silicon carbide wafer by pressing the cleaver on the cutting path.

[0039] 4. The device of the present application can improve the technical indicators such as collapse and straightness of the silicon carbide wafer after cutting, avoid the tearing phenomenon of the metal layer on the back surface, and improve the product yield. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 The figure is a flowchart of the laser cutting method of the embodiment of the present application based on the silicon carbide wafer.

[0041] Figure 2 The figure is a schematic diagram of the film sticking and glue coating mechanism in embodiment 1 of the present application.

[0042] Figure 3 The figure is a schematic diagram of the first cutting mechanism in embodiment 1 of the present application.

[0043] Figure 4 The figure is a schematic diagram of the second cutting mechanism in embodiment 1 of the present application.

[0044] Figure 5 The figure is a schematic diagram of the cutting process of the second cutting mechanism in embodiment 1 of the present application.

[0045] Figure 6 The figure is a schematic diagram of the second cutting mechanism in embodiment 2 of the present application.

[0046] In all the drawings, the same reference signs represent the same technical features, specifically: 1 - glue coating and cleaning platform suction cup, 2 - iron ring, 3 - cutting film, 4 - silicon carbide wafer, 5 - water-soluble glue, 6 - cutting channel, 7 - glue coating head, 8 - cleaning head, 9 - transparent suction cup, 10 - first CCD, 11 - first laser, 12 - laser surface cutting platform, 13 - microporous ceramic suction cup, 14 - second laser, 15 - second CCD, 16 - laser hidden cutting platform, 17 - splitting knife, 18 - support platform, 19 - protective film. DETAILED DESCRIPTION

[0047] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application is further described in detail below with reference to the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0048] As shown in Figure 1 The present application provides a laser cutting method based on a silicon carbide wafer, which comprises the following steps: first, placing the silicon carbide wafer with the back surface facing up and the cutting film attached on the glue coating and cleaning platform, then dropping water-soluble glue at the center of the back surface of the wafer, and coating the entire back surface of the wafer with glue evenly by rotating the platform; after the glue is air-dried, placing the silicon carbide wafer on the transparent suction cup of the laser surface cutting platform, identifying and positioning the cutting channel position on the front surface of the silicon carbide wafer by using the first CCD visual imaging, and generating a cutting path; focusing the ultraviolet laser on the metal layer on the back surface of the silicon carbide wafer, adjusting the process parameters such as the repetition frequency, power and platform scanning speed of the ultraviolet laser along the preset cutting path, completely removing the metal layer on the back surface, and forming a V-shaped groove. After cutting is completed, placing the silicon carbide wafer on the glue coating and cleaning platform, washing the water-soluble glue with pure water, and reattaching the protective film to the silicon carbide wafer to ensure that the front surface faces up. Then, placing the silicon carbide wafer on the microporous ceramic suction cup of the laser hidden cutting platform, identifying and positioning the cutting channel position on the front surface of the silicon carbide wafer by using the second CCD visual imaging, and generating a cutting path, focusing the infrared laser on the inside of the silicon carbide wafer, adjusting the process parameters such as the repetition frequency, power, platform scanning speed and cutting times of the infrared laser along the preset cutting path, and performing laser modification cutting in each cutting channel. Finally, covering the protective film on the front surface of the cut silicon carbide wafer, and pressing the splitting knife on the cutting channel to separate the chips one by one. The method of the present application uses ultraviolet laser and infrared laser to cut the metal layer on the back surface and the non-metal layer on the front surface of the silicon carbide wafer respectively, and uses the cutting effects of different lasers to solve the problems of back metal tearing and front surface edge collapse and poor straightness in the current cutting methods.

[0049] In the embodiment of the present application, the front surface of the silicon carbide wafer is a structure layer, a small amount of metal covers the cutting path, the back surface is a full metal layer with a thickness of 5 μm or less, the film is attached to the cutting film, and the film is carried by the iron ring, the highest rotating speed of the glue coating and cleaning platform is 100 r / min-3000 r / min, the transparent suction cup is a quartz transparent suction cup, the first CCD is stably imaged through the suction cup and the glue film, the width of the cutting path of the structure surface of the silicon carbide device is not less than 20 μm, the first laser is an ultraviolet laser with a wavelength of 355 nm, and the power fluctuation range is less than 0.1 W, the second laser is an infrared laser with a wavelength of 1064 nm, and the power fluctuation range is less than 0.01 W, the width of the V groove cannot be greater than the width of the cutting path, and the depth cannot exceed the thickness of the metal, the cutting position deviation of the first laser and the second laser on the silicon carbide wafer is not more than ± 5 μm, the power stability of the infrared laser is high, the power fluctuation range is less than 0.01 W, and the width of the blade of the splitting knife is not higher than 20 μm. The method of the present application focuses the first laser on the metal layer on the back surface of the silicon carbide wafer, adjusts the repetition frequency, power and platform scanning speed process parameters along the first cutting path to form a V groove, and realizes the cutting of the metal layer on the back surface of the silicon carbide wafer. The second laser is focused on the inside of the silicon carbide wafer, the repetition frequency, power, platform scanning speed and cutting times of the laser are adjusted along the second cutting path, laser modification cutting is carried out in each cutting path, the protective film is covered on the front surface of the cut silicon carbide wafer, the splitting knife is pressed on the cutting path, and the cutting of the non-metal layer on the front surface of the silicon carbide wafer is realized.

[0050] Embodiment 1

[0051] In one embodiment of the present application, a laser cutting method based on a silicon carbide wafer is provided, and the basic principle of the device is as shown in Figures 2-5 The device includes a glue coating and cleaning platform suction cup (1), an iron ring (2), a cutting film (3), a silicon carbide wafer (4), water-soluble glue (5), a cutting path (6), a glue coating head (7), a cleaning head (8), a transparent suction cup (9), a first CCD (10), a first laser (11), a laser surface cutting platform (12), a microporous ceramic suction cup (13), a second laser (14), a second CCD (15), a laser hidden cutting platform (16), a splitting knife (17), a supporting platform (18), and a protective film (19).

[0052] The silicon carbide wafer (4) is placed with the front side cutting channel (6) facing down and the back metal layer facing up, the cutting film (3) is attached to the silicon carbide wafer (4), the silicon carbide wafer (4) with the attached cutting film (3) is adsorbed on the glue coating and cleaning platform suction disc (1) by negative pressure, the glue coating head (7) is moved to the center of the silicon carbide wafer (4), the water-soluble glue (5) is dropped, and then the glue coating and cleaning platform suction disc (1) is rotated to ensure that the glue is evenly coated on the surface of the silicon carbide wafer. The silicon carbide wafer (4) coated with the water-soluble glue (5) is adsorbed on the transparent suction disc (9) by negative pressure, the position of the cutting channel (6) on the wafer is identified by the first CCD (10), a cutting path is generated, the first laser (11) of the laser surface cutting platform (12) is focused on the back metal layer of the wafer, the wafer adsorbed by the transparent suction disc (9) is driven to move back and forth by the laser surface cutting platform (12), the back metal layer of the wafer is removed, and a V-shaped groove is formed. The silicon carbide wafer after laser surface cutting is placed on the glue coating and cleaning platform suction disc (1), the suction disc is rotated and the cleaning head (8) is moved, and the water-soluble glue is washed away by the sprayed water mist; the cleaned silicon carbide wafer (4) is reattached with the cutting film, ensuring that the front side cutting channel (6) faces up and the back metal layer faces down; the silicon carbide wafer (4) with the attached cutting film (3) is adsorbed on the microporous ceramic suction disc (13) of the laser hidden cutting platform (16) by negative pressure, the position of the cutting channel (6) of the wafer is identified by the second CCD (15), a cutting path is generated, the second laser (14) of the laser hidden cutting platform (16) is focused on the inside of the wafer, the wafer adsorbed by the microporous ceramic suction disc (13) is driven to move back and forth by the laser hidden cutting platform (16), and a modified layer is formed in the wafer; the surface of the silicon carbide wafer (4) after laser surface cutting and laser hidden cutting is covered with a protective film (19), and is placed on a support platform (18); the cleaving knife (17) is moved to align with the position of the cutting channel (6), the cleaving knife is pressed down to split the wafer, and the separation of the silicon carbide wafer (4) is realized.

[0053] Further, the front side of the silicon carbide wafer 4 is a structure layer, a small amount of metal covers the cutting channel, and the back side is a full metal layer with a thickness of 5 μm or less;

[0054] Further, the glue coating head 7 drops glue with a capacity of 5 ml, 10 ml, 15 ml, etc. according to the size of the wafer and the viscosity of the glue;

[0055] Further, the rotation speed of the glue coating and cleaning platform can be first low speed 100 r / min and then high speed 2000 r / min, and the glue is air dried, and the highest rotation speed of the platform is 3000 r / min;

[0056] Further, the transparent suction disc is a quartz transparent suction disc, and the first CCD forms stable imaging through the suction disc and the glue film;

[0057] Further, the depth of the V-shaped groove should be less than the thickness of the metal layer on the back of the silicon carbide wafer 4, and the width should be less than the width of the cutting path 6.

[0058] Further, the first laser 11 is an ultraviolet laser with a wavelength of 355 nm, and the power fluctuation range is less than 0.1 W.

[0059] Further, the water mist sprayed by the cleaning head 8 is composed of compressed air and pure water.

[0060] Further, the width of the cutting path of the silicon carbide device structure surface is not less than 20 μm.

[0061] Further, the cutting position deviation of the first laser 11 and the second laser 14 on the silicon carbide wafer 4 should not exceed ±5 μm.

[0062] Further, the second red laser 14 has a wavelength of 1064 nm, and the power fluctuation range is less than 0.01 W.

[0063] Further, the position of the support platform 18 should be on both sides of the position of the cleaver 17.

[0064] Further, the width of the blade of the cleaver 17 should not be higher than 20 μm.

[0065] Embodiment 2

[0066] In another embodiment of the present application, a laser cutting method based on a silicon carbide wafer is provided, and the device is as shown in Figure 6 The device includes a glue-coated cleaning platform suction cup (1), an iron ring (2), a cutting film (3), a silicon carbide wafer (4), water-soluble glue (5), a cutting path (6), a glue-coated head (7), a cleaning head (8), a transparent suction cup (9), a first CCD (10), a first laser (11), a laser surface cutting platform (12), a microporous ceramic suction cup (13), a second laser (14), a second CCD (15), a laser hidden cutting platform (16), a cleaver (17), a support platform (18), and a protective film (19).

[0067] The silicon carbide wafer (4) is placed with the front side cutting channel (6) facing down and the back metal layer facing up, the cutting film (3) is attached to the silicon carbide wafer (4) with the iron ring (2), the silicon carbide wafer (4) with the attached film is adsorbed on the glue coating and cleaning platform suction disc (1) by negative pressure, the glue coating head (7) is moved to the center of the silicon carbide wafer (4), the water-soluble glue (5) is dropped, and then the glue coating and cleaning platform suction disc (1) is rotated to ensure that the glue is evenly coated on the surface of the silicon carbide wafer. The silicon carbide wafer (4) coated with water-soluble glue (5) is adsorbed on the transparent suction disc (9) by negative pressure, the position of the cutting channel (6) on the wafer is identified by the first CCD (10), the cutting path is generated, the first laser (11) of the laser surface cutting platform (12) is focused on the back metal layer of the wafer, the wafer adsorbed by the transparent suction disc (9) is driven by the laser surface cutting platform (12) to move back and forth, and the back metal layer of the wafer is removed to form a V-shaped groove. The silicon carbide wafer after laser surface cutting is placed on the glue coating and cleaning platform suction disc (1), the suction disc is rotated and the cleaning head (8) is moved, and the water-soluble glue is washed away by the sprayed water mist; the cleaned silicon carbide wafer (4) is reattached with the film to ensure that the front side cutting channel (6) faces up and the back metal layer faces down; the silicon carbide wafer (4) with the attached cutting film (3) is adsorbed on the microporous ceramic suction disc (13) of the laser hidden cutting platform (16) by negative pressure, the position of the cutting channel (6) of the wafer is identified by the second CCD (15), the cutting path is generated, the second laser (14) of the laser hidden cutting platform (16) is focused on the inside of the wafer, the wafer adsorbed by the microporous ceramic suction disc (13) is driven by the laser hidden cutting platform (16) to move back and forth, and a modified layer is formed in the wafer; the silicon carbide wafer (4) after laser surface cutting and laser hidden cutting is reattached with the film to ensure that the front side cutting channel (6) faces down and the back metal layer faces up, and a protective film (19) is covered on the surface of the wafer, and then the wafer is placed on the supporting platform (18); the splitting knife (17) is moved to align with the position of the cutting channel (6), the splitting knife is pressed down to split the wafer, and the separation of the silicon carbide wafer (4) is realized.

[0068] Further, the front side of the silicon carbide wafer 4 is a structure layer, a small amount of metal covers the cutting channel, and the back side is a full metal layer with a thickness of 5 μm or less;

[0069] Further, the glue capacity dropped by the glue coating head 7 can be selected as 5 ml, 10 ml, 15 ml, etc. according to the size of the wafer and the viscosity of the glue;

[0070] Further, the rotation speed of the glue coating and cleaning platform can be first low speed 100 r / min and then high speed 2000 r / min, and the glue is air dried, and the highest rotation speed of the platform is 3000 r / min;

[0071] Further, the transparent suction disc is a quartz transparent suction disc, and the first CCD forms stable imaging through the suction disc and the film;

[0072] Further, the depth of the V groove should be less than the thickness of the back metal layer of the silicon carbide wafer 4, and the width should be less than the width of the cutting path 6.

[0073] Further, the first laser 11 is an ultraviolet laser with a wavelength of 355 nm, and the power fluctuation range is less than 0.1 W.

[0074] Further, the water mist sprayed by the cleaning head 8 is a two-fluid composed of compressed air and pure water.

[0075] Further, the width of the cutting path of the silicon carbide device structure surface is not less than 20 μm.

[0076] Further, the cutting position deviation of the first laser 11 and the second laser 14 on the silicon carbide wafer 4 cannot exceed ±5 μm.

[0077] Further, the second laser 14 is a red laser with a wavelength of 1064 nm, and the power fluctuation range is less than 0.01 W.

[0078] Further, the position of the support platform 18 needs to be on both sides of the pressing position of the cleaver 17.

[0079] Further, the width of the blade of the cleaver 17 is not higher than 20 μm.

[0080] The device of the present application can improve the technical indicators such as edge collapse and straightness of the silicon carbide wafer after cutting, avoid the tearing phenomenon of the back metal layer, and improve the product yield.

[0081] Those skilled in the art can easily understand that the above description is only a preferred embodiment of the present application, and is not used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method of laser cutting based on a silicon carbide wafer, characterized by, Comprising: S100: a film pasting and gluing mechanism, which comprises a gluing and cleaning platform suction disc, an iron ring, a cutting film, and a gluing head, the film pasting and gluing mechanism places the silicon carbide wafer with the back upward and the cutting film pasted on it on the gluing and cleaning platform, then drops water-soluble glue at the center of the back of the wafer, and rotates the platform to evenly coat the entire back of the wafer with the glue; S200: after the glue is dried, the silicon carbide wafer is placed on a transparent suction disc of a laser surface cutting platform, a first CCD visual imaging is used to identify and locate the position of the front cutting path of the silicon carbide wafer, and a first cutting path is generated; S300: the first laser is an ultraviolet laser, the first laser is focused on the metal layer on the back of the silicon carbide wafer, along the first cutting path, the frequency, power and platform scanning speed process parameters of the laser are controlled, the metal layer on the back of the wafer is completely removed, and a V groove is formed; S400: after cutting is completed, the silicon carbide wafer is placed on the gluing and cleaning platform, pure water is used to wash the water-soluble glue clean, and the silicon carbide wafer is pasted with a film again to ensure that the front is upward, the silicon carbide wafer is placed on a microporous ceramic suction disc of a laser hidden cutting platform, a second CCD visual imaging is used to identify and locate the position of the front cutting path of the silicon carbide wafer, and a second cutting path is generated; S500: the second laser is an infrared laser, the second laser is focused inside the silicon carbide wafer, along the second cutting path, the frequency, power and platform scanning speed, cutting times process parameters of the laser are controlled, laser modification cutting is performed in each cutting path, and a protective film is covered on the front of the cut silicon carbide wafer, a splitting knife is pressed on the cutting path to realize the separation of each chip.

2. The method of claim 1, wherein the silicon carbide wafer is a 4H-SiC wafer. The front of the silicon carbide wafer is a structure layer, and a part of the region in the cutting path is covered with a metal layer.

3. The method of claim 2, wherein the laser cutting is performed by a laser beam having a wavelength of 355 nm. The back of the silicon carbide wafer is a full metal layer with a thickness less than or equal to 5µm.

4. The method of laser cutting of a silicon carbide wafer according to any one of claims 1 to 3, wherein In step S100, the silicon carbide wafer is carried by the iron ring and pasted on the cutting film.

5. The method of claim 4, wherein the laser cutting is performed by a laser beam having a wavelength of 355 nm. In step S100, the rotating speed of the gluing and cleaning platform is 100r / min-3000r / min.

6. The method of claim 5, wherein the laser cutting is performed by a laser beam having a wavelength of 355 nm. In step S100, the capacity of the glue is determined according to the size of the silicon carbide wafer and the viscosity of the glue, which is 5ml-15ml.

7. The method of laser cutting of silicon carbide wafers according to any one of claims 1-3, wherein, In step S300, the depth of the V groove should be less than the thickness of the metal layer on the back of the silicon carbide wafer, and the width should be less than the width of the cutting path.

8. The method of claim 7, wherein the laser cutting is performed by a laser beam having a wavelength of 355 nm. In step S300, the first laser is an ultraviolet laser with a wavelength of 355nm, and the power fluctuation range is less than 0.1W.

9. The method of claim 8, wherein the laser cutting is performed by a laser beam having a wavelength of 355 nm. In step S500, the second laser is an infrared laser with a wavelength of 1064nm, and the power fluctuation range is less than 0.01W.

10. The method of claim 9, wherein the laser cutting is performed by a laser beam having a wavelength of 355 nm. The cutting position deviation of the first laser and the second laser on the silicon carbide wafer is not more than ±5µm.

11. A method of laser cutting of silicon carbide wafers according to any one of claims 1-3, wherein, In step S500, the width of the cutting path is not less than 20µm.

12. The method of claim 11, wherein the laser cutting is performed by a laser beam having a wavelength of 355 nm. The width of the blade of the splitting knife is not higher than 20µm.

13. A laser cutting apparatus based on a silicon carbide wafer, characterized by Comprising: The film pasting and glue applying mechanism comprises a glue applying and cleaning platform suction disc (1), an iron ring (2), a cutting film (3) and a glue applying head (7), which is used for placing the silicon carbide wafer with the back upward and the cutting film pasted on the glue applying and cleaning platform, then dropping water-soluble glue at the center of the back of the wafer, and rotating the platform to uniformly apply the glue to the entire back of the wafer; The first cutting path planning mechanism is used for placing the silicon carbide wafer on a transparent suction disc of a laser surface cutting platform, identifying and positioning the cutting path position on the front of the silicon carbide wafer by using a first CCD visual imaging, and generating a first cutting path. The first cutting mechanism is used for emitting first laser to focus on the metal layer on the back of the silicon carbide wafer, the first laser is ultraviolet laser, along the first cutting path, the frequency, power and platform scanning speed process parameters of the laser are controlled, the metal layer on the back of the wafer is completely removed, and a V groove is formed. The second cutting path planning mechanism is used for placing the silicon carbide wafer on the glue applying and cleaning platform, washing the water-soluble glue clean by using pure water, and pasting the film on the silicon carbide wafer again, ensuring that the front is upward, placing the silicon carbide wafer on a micro-porous ceramic suction disc of a laser hidden cutting platform, identifying and positioning the cutting path position on the front of the silicon carbide wafer by using a second CCD visual imaging, and generating a second cutting path. The second cutting mechanism is used for emitting second laser to focus on the inside of the silicon carbide wafer, the second laser is infrared laser, along the second cutting path, the frequency, power and platform scanning speed, cutting times process parameters of the laser are controlled, laser modification cutting is performed in each cutting path, and the protective film is covered on the front of the cut silicon carbide wafer, the splitting knife is pressed on the cutting path to realize the separation of each chip.

14. The silicon carbide wafer-based laser cutting apparatus of claim 13, wherein, The first cutting path planning mechanism comprises a transparent suction disc (9) and a first CCD (10), the silicon carbide wafer (4) is adsorbed on the transparent suction disc (9) by negative pressure, the position of the cutting path (6) on the wafer is identified by the first CCD (10), and a first cutting path is generated.

15. A silicon carbide wafer-based laser cutting apparatus as defined in claim 14, wherein, The first cutting mechanism comprises a first laser (11) and a laser surface cutting platform (12).

16. A silicon carbide wafer-based laser cutting apparatus as defined in claim 15, wherein, The second cutting path planning mechanism comprises a cleaning head (8), a micro-porous ceramic suction disc (13), a second CCD (15) and a laser hidden cutting platform (16).

17. A silicon carbide wafer-based laser cutting apparatus as defined in claim 16, wherein, The second cutting mechanism comprises a second laser (14), a splitting knife (17), a supporting platform (18) and a protective film (19).

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