A double laser cutting method of gallium oxide

Abstract

This application discloses a dual-laser cutting method for gallium oxide, belonging to the field of laser cutting. It includes: using a first laser capable of forming a first laser path with an average output power greater than 30W, a wavelength of 1020nm-1090nm, and a pulse width of less than 10ns to laser cut the workpiece; using a second laser capable of forming a second laser path with a wavelength of 310nm-380nm, a pulse width of less than 50ps, a peak pulse power greater than 200kW, and a repetition frequency greater than 100kHz to laser cut the workpiece; and performing a film expansion process on the workpiece after processing by the second laser to obtain a wafer; wherein the second laser cuts the workpiece after it has been cut by the first laser.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of laser cutting, in particular, a double laser cutting method of gallium oxide. BACKGROUND

[0002] As a new generation of semiconductor material, gallium oxide (β-Ga2O3) has the advantages of super-wide band gap, high breakdown electric field strength, high ultraviolet transmittance, stable physical and chemical properties, etc., and can be widely used in the fields of microelectronics, optoelectronics, power devices, etc. In the field of microelectronics, gallium oxide is used in the manufacture of high-frequency field effect transistors, surface acoustic wave filters and microwave switches due to its fast response to high-frequency electric field. In the field of optoelectronics, its band gap matches the visible light, and is suitable for LED lamps, thin-film solar panels and new-type photoelectric sensors. In the field of power devices, gallium oxide has a wide band gap (~4.8eV) and can work at higher voltage and power density;

[0003] Compared with silicon carbide, it has higher performance potential; however, the 100 crystal surface of β-Ga2O3 has strong cleavage and brittleness, so when cutting it, the crystal surface is prone to separation and cracking.

[0004] Patent document 202180080243.9 proposes a separation method of β-Ga2O3. Referring to the accompanying drawings Figure 2 The patent proposes using a gallium oxide substrate with a second crystal surface as the main surface, setting the direction parallel to the intersection line of the main surface and the first crystal surface as the X direction, performing mechanical scribing processing on the main surface by scribing tool tip along the cutting predetermined line parallel to the X direction, and performing laser scribing processing by scanning the laser beam along the cutting predetermined line parallel to the Y direction to modify the cutting predetermined line. The cutting predetermined line is disconnected along the X direction and the Y direction after the mechanical scribing processing and the laser scribing processing. The patent mainly uses the easy cleavage characteristics of the first crystal surface to obtain the cutting line by mechanical scribing and laser scribing. It has been verified that in addition to inducing longitudinal cracks in the first crystal surface, mechanical scribing also causes transverse cracks, so that crack propagation occurs during the disconnection process, resulting in the presence of edge collapse in the obtained wafer. This problem makes this method only applicable to smaller size β-Ga2O3, and the processing quality is low. SUMMARY

[0005] The summary part of the present application is used to introduce the concepts in a brief form, which will be described in detail in the specific embodiment part. The summary part of the present application is not intended to identify the key features or essential features of the claimed technical solution, nor is it intended to limit the scope of the claimed technical solution.

[0006] To solve the technical problems mentioned in the background section, some embodiments of the present application provide a double laser cutting method for gallium oxide, which is used for cutting a workpiece to be cut, and the workpiece to be cut has a first crystal surface, a second crystal surface and a third crystal surface connected to each other; the first crystal surface is a surface with strong cleavage and strong brittleness; the cutting method comprises: using a first laser capable of forming a first laser light path with an average output power greater than 30W, a wavelength of 1020nm-1090nm and a pulse width less than 10ns to cut the first crystal surface of the workpiece to be cut; using a second laser capable of forming a second laser light path with a wavelength of 310nm-380nm, a pulse width less than 50ps and a peak power of the pulse greater than 200kW and a repetition frequency greater than 100kHz to cut the second crystal surface or the third crystal surface of the workpiece to be cut; and the workpiece to be cut after being processed by the second laser is subjected to film expansion treatment to obtain a wafer body; wherein the second laser cuts the workpiece to be cut after being cut by the first laser.

[0007] Further, one end of the workpiece to be cut is provided with a heat conduction layer, and the other end is provided with a film expansion layer; the laser emitted by the first laser and the laser emitted by the second laser are both irradiated on the heat conduction layer.

[0008] Further, the heat conduction layer is formed by one or more micro-nanoparticles of diamond, silver, copper, gold, aluminum nitride, silicon carbide, aluminum, graphite and zinc; and the film expansion layer is one of polyethylene film, polyimide film, polyamide film or fluorinated polymer film.

[0009] Further, the method further comprises: forming a light spot capable of moving along a first preset track on the workpiece to be cut by the first laser light path through a first driving member; and forming a light spot capable of moving along a second preset track on the workpiece to be cut by the second laser light path through a second driving member.

[0010] Further, the first driving member comprises a first optical scanning member and a first converging optical member; the first converging optical member is used to enable the first laser to form a light spot; and the first optical scanning member is used to enable the light spot to move along the first preset track.

[0011] Further, the upper end surface of the workpiece to be cut is defined as a first surface, the front end surface of the workpiece to be cut is defined as a second surface, the right end surface of the workpiece to be cut is defined as a third surface, and the lower end surface of the workpiece to be cut is defined as a fourth surface; the heat conduction layer is arranged on the first surface, and the film expansion layer is arranged on the fourth surface; and the first driving member causes the first laser light path to be incident on the upper end surface in a direction parallel to the front end surface.

[0012] Further, the method further comprises: expanding the first laser light path using a first beam expander, and expanding the second laser light path using a second beam expander.

[0013] Further, the method further comprises: placing the workpiece to be cut on a moving carrier, and moving the workpiece to be cut by the moving carrier.

[0014] Further, the method of setting the heat-conducting layer at one end of the workpiece to be cut comprises one or more of evaporation, melting sintering, electron beam evaporation, electroplating, and magnetron sputtering.

[0015] Further, the first laser light path has an average output power of 50 W, a wavelength of 1040 nm, and a pulse width less than 50 ns; and the second laser light path has a wavelength of 355 nm, a pulse width less than 20 ps, and a peak power of 500 kW.

[0016] The beneficial effects of the present application are as follows: a double laser cutting method is adopted, the first crystal surface is first laser-cut along the first crystal surface to form a crack extension layer, the second crystal surface or the third crystal surface is then laser-cut to obtain a wafer to be separated, and finally, the wafer is separated by a film expansion machine to obtain a gallium oxide wafer with excellent processing quality and few cutting defects. BRIEF DESCRIPTION OF DRAWINGS

[0017] The accompanying drawings, which form a part of this application, are included to provide a further understanding of the application and are incorporated in and constitute a part of this application. The drawings illustrate embodiments of the present application and, together with the description, serve to explain the principles of the present application.

[0018] In addition, throughout the drawings, same or similar reference numerals are used to denote same or similar elements. It should be understood that the drawings are schematic, and elements and elements are not necessarily drawn to scale.

[0019] In the drawings:

[0020] Figure 1 is a flow chart diagram according to the present application as a whole;

[0021] Figure 2 is a schematic diagram according to an embodiment of the present application as a whole;

[0022] Figure 3 is a structural schematic diagram of a part of the embodiment, mainly showing the structure of the workpiece to be cut;

[0023] Figure 4 is the structure of the workpiece to be cut, the heat-conducting layer, and the film expansion layer.

[0024] Reference numerals:

[0025] 1, first laser; 2, second laser; 3, first driving member; 4, second driving member; 5, first optical scanning element; 6, first optical focusing element; 7, first beam expander; 8, moving carrier; 9, heat conduction layer; 10, expanded film layer; 11, workpiece to be cut. DETAILED DESCRIPTION

[0026] Embodiments of the present disclosure will be described in more detail with reference to the drawings. Although certain embodiments of the present disclosure are shown in the drawings, it is understood that the present disclosure can be implemented in various forms and should not be interpreted as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure can be more thoroughly and completely understood. It should be understood that the drawings of the present disclosure are only for illustrative purposes and are not intended to limit the scope of protection of the present disclosure.

[0027] In addition, it should be further noted that only parts related to the present application are shown in the drawings for ease of description. The embodiments in the present disclosure and the features in the embodiments can be combined with each other without conflict.

[0028] It should be noted that the terms "first", "second" and the like mentioned in the present disclosure are only used to distinguish different devices, modules or units, and are not intended to limit the order or interdependence of the functions performed by these devices, modules or units.

[0029] It should be noted that the adjectives "one", "multiple" mentioned in the present disclosure are illustrative and not restrictive, and those skilled in the art should understand that unless otherwise explicitly stated in the context, it should be understood as "one or more".

[0030] The present disclosure will be described in detail below with reference to the drawings and in conjunction with embodiments.

[0031] Reference Figures 1-4 ,

[0032] A double laser cutting method of gallium oxide, the cutting method is used for cutting a workpiece to be cut, the workpiece to be cut is formed with a first crystal surface, a second crystal surface and a third crystal surface connected with each other; the first crystal surface is a surface with strong cleavage and strong brittleness; the cutting method comprises: using a first laser capable of forming a first laser light path with an average output power greater than 30W, a wavelength of 1020nm-1090nm and a pulse width less than 10ns to laser cut the first crystal surface of the workpiece to be cut; using a second laser capable of forming a second laser light path with a wavelength of 310nm-380nm, a pulse width less than 50ps and a peak power of the pulse greater than 200kW and a repetition frequency greater than 100kHz to laser cut the second crystal surface or the third crystal surface of the workpiece to be cut. Referring to the drawings Figure 2The first crystal face is a (100) crystal face, the second crystal face is a (001) crystal face, and the third crystal face is a (010) crystal face.

[0033] The first laser of the first laser light path is used to perform laser cutting on a first crystal face of the workpiece to be cut, and the second laser of the second laser light path is used to perform laser cutting on a second crystal face of the workpiece to be cut. The workpiece to be cut processed by the second laser is subjected to film expansion treatment to obtain a wafer body. Specifically, the film expansion treatment is achieved by using a film expansion machine. The second laser is used to cut the workpiece to be cut processed by the first laser.

[0034] The first laser light path adopts nanosecond laser to form a crack extension layer on the workpiece to be cut. Since the first laser is provided with the advantage of high pulse energy, cleavage of the workpiece to be cut can be rapidly caused, and the phenomenon that the crack extends to other directions does not occur. The second laser light path adopts ultrafast laser to cause modification inside the gallium oxide to obtain a pre-separation interface. Since the ultrafast laser has the advantage of extremely small heat-affected zone, the crack in the easy cleavage direction does not occur.

[0035] Specifically, one end of the workpiece to be cut is provided with a heat conduction layer, and the other end is provided with a film expansion layer. The laser emitted by the first laser and the laser emitted by the second laser are both irradiated on the heat conduction layer. The heat conduction layer is formed by one or more micro-nanoparticles of diamond, silver, copper, gold, aluminum nitride, silicon carbide, aluminum, graphite and zinc. The film expansion layer is one of polyethylene film, polyimide film, polyamide film or fluorinated polymer film. By pre-covering the upper surface of the wafer with the heat conduction layer, the local heat generated by the laser is diffused in time, and the obvious thermal cracks on the surface of the workpiece to be cut are avoided.

[0036] Specifically, the method further comprises: forming a light spot capable of moving along a first preset track on the workpiece to be cut by the first laser light path through a first driving member; and forming a light spot capable of moving along a second preset track on the workpiece to be cut by the second laser light path through a second driving member. The first driving member comprises a first optical scanning member and a first converging optical member. The first converging optical member is used to form a light spot by the first laser. The first optical scanning member is used to move the light spot along the first preset track. The structure of the second driving member matches the structure of the first driving member.

[0037] Specifically, the upper end surface of the workpiece to be cut is defined as a first surface, the front end surface of the workpiece to be cut is defined as a second surface, the right end surface of the workpiece to be cut is defined as a third surface, and the lower end surface of the workpiece to be cut is defined as a fourth surface; the heat conduction layer is arranged on the first surface, and the film expansion layer is arranged on the fourth surface; the first driving member causes the first laser light path to be incident on the upper end surface in a direction parallel to the front end surface.

[0038] Specifically, the method further includes expanding the first laser light path using a first beam expander and expanding the second laser light path using a second beam expander. The method further includes placing the workpiece to be cut on a moving carrier, and the moving carrier moves the workpiece to be cut. The method of arranging the heat conduction layer at one end of the workpiece to be cut includes one or more of evaporation, melting sintering, electron beam evaporation, electroplating, and magnetron sputtering.

[0039] The above description is merely some of the preferred embodiments of the present disclosure and a description of the principles of the technology used. Those skilled in the art should understand that the scope of the application involved in the embodiments of the present disclosure is not limited to the technical solutions formed by the specific combinations of the above technical features, and should also cover other technical solutions formed by any combinations of the above technical features or equivalent features without departing from the above inventive concept. For example, the above features are replaced with the technical features disclosed in the embodiments of the present disclosure (but not limited to) having similar functions to form technical solutions.

Claims

1. A dual-laser cutting method for gallium oxide, the cutting method being used to cut a workpiece, wherein a first crystal plane, a second crystal plane, and a third crystal plane are formed on the workpiece; the first crystal plane is a surface with strong cleavage and brittleness; characterized in that, The cutting method includes: using a first laser capable of forming a first laser optical path with an average output power greater than 30W, a wavelength of 1020nm-1090nm and a pulse width of less than 10ns to perform laser cutting on the first crystal plane of the workpiece to be cut. A second laser capable of forming a second laser optical path with a wavelength of 310nm-380nm, a pulse width of less than 50ps, a peak power of more than 200kW, and a repetition frequency of more than 100kHz is used to laser cut the second or third crystal plane of the workpiece to be cut. The workpiece to be cut after being processed by the second laser undergoes a film expansion process to obtain a wafer. The second laser cuts the workpiece to be cut after it has been cut by the first laser; a heat-conducting layer is provided at one end of the workpiece to be cut, and an expansion film layer is provided at the other end. Both the laser emitted by the first laser and the laser emitted by the second laser irradiate the thermally conductive layer; the thermally conductive layer is formed of one or more micro / nano particles of diamond, silver, copper, gold, aluminum nitride, silicon carbide, aluminum, graphite and zinc. The expanded film layer is one of polyethylene film, polyimide film, polyamide film, or fluorinated polymer film.

2. The dual laser cutting method for gallium oxide according to claim 1, characterized in that: The method further includes: using a first driving component to form a light spot on the workpiece to be cut that can move along a first preset trajectory on the first laser light path; The second driving component causes the second laser beam path to form a spot on the workpiece to be cut that can move along a second preset trajectory.

3. The dual laser cutting method for gallium oxide according to claim 2, characterized in that: The first driving element includes a first optical scanning element and a first focusing optical element; The first focusing optics enables the first laser to form a light spot; the first optical scanning element enables the light spot to move along the first preset trajectory.

4. The dual laser cutting method for gallium oxide according to claim 3, characterized in that: The upper end face of the workpiece to be cut is defined as the first face, the front end face of the workpiece to be cut is defined as the second face, the right end face of the workpiece to be cut is defined as the third face, and the lower end face of the workpiece to be cut is defined as the fourth face. The thermally conductive layer is disposed on the first surface, and the film-expanding layer is disposed on the fourth surface; The first driving member causes the first laser beam to be incident on the upper end surface in a direction parallel to the front end surface.

5. The dual laser cutting method for gallium oxide according to claim 4, characterized in that: The method further includes: using a first beam expander to expand the first laser beam path, and using a second beam expander to expand the second laser beam path.

6. The dual laser cutting method for gallium oxide according to claim 5, characterized in that: The method further includes placing the workpiece to be cut on a movable carrier, the movable carrier driving the workpiece to be cut to move.

7. The dual laser cutting method for gallium oxide according to claim 6, characterized in that: Methods for setting a heat-conducting layer at one end of the workpiece to be cut include one or more of the following: evaporation, melt sintering, electron beam evaporation, electroplating, and magnetron sputtering.

8. The dual laser cutting method for gallium oxide according to claim 7, characterized in that: The average output power of the first laser optical path is 50W, the wavelength is 1040nm, and the pulse width is less than 50ns. The second laser path has a wavelength of 355nm, a pulse width of less than 20ps, and a peak pulse power of 500kW.

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