Three-step stripping device for gallium oxide

Abstract

The utility model discloses a three-step stripping device for gallium oxide, and belongs to the field of wafer stripping device design. Comprising a pre-cutting unit used for annularly cutting a separation surface on the circumference of a wafer; the laser processing unit emits low-power laser beams, and the laser beams are focused on a focusing plane in the wafer to form laser spots; the separation unit is used for reversely pulling the wafer parts on the two sides of the separation surface; and the moving unit is used for clamping the wafer and sequentially moving the wafer to the pre-cutting unit, the laser processing unit and the separating unit. The pre-cutting device has the beneficial effects that the pre-cutting unit is provided for annularly cutting the separation surface of the wafer, the wafer loss is reduced while the circumferential strength of the wafer is reduced, low-power laser emitted by the laser processing unit is focused on the focusing plane of the wafer for modification, the internal strength of the wafer is reduced while microcracks in the wafer are reduced, and the quality of the wafer is improved. And finally, the wafer can be easily separated into two parts by the separation unit.

Description

Technical Field

[0001] The present application relates to the field of wafer stripping device design, and in particular, to a three-step stripping device for gallium oxide. Background Art

[0002] As a new generation of semiconductor materials, gallium oxide (β-Ga2O3) has the advantages of ultra-wide bandgap, high breakdown electric field strength, high ultraviolet transmittance, and stable physical and chemical properties. It can be widely used in microelectronics, optoelectronics, power devices and other fields. In the field of microelectronics, gallium oxide is used in the manufacture of devices such as high-frequency field effect transistors, surface acoustic wave filters and microwave switches because it can quickly respond to high-frequency electric fields. In the field of optoelectronics, its band gap matches visible light and is suitable for devices such as LED lights, thin-film solar panels and new photoelectric sensors. In the field of power devices, gallium oxide has a wide bandgap characteristic (~4.8eV) and can operate at higher voltages and power densities, and has higher performance potential than silicon carbide.

[0003] At present, one way to cut gallium oxide wafers is to use a diamond wire saw, but this cutting method will cause great loss of gallium oxide. Another general method is to use an ultrashort pulse laser with a predetermined wavelength to irradiate the inside of the gallium oxide, so that the laser is focused at a position of a specific thickness from the surface to cause a two-photon absorption process. The high temperature generated by this process causes the gallium oxide to be thermally modified, thereby achieving the purpose of peeling the wafer. This cutting method will cause too many microcracks near the modified layer when the peak power of the laser is high, resulting in a prolonged subsequent polishing process and increased actual loss. If the peak power of the laser is too low, the upper and lower wafers of the modified layer will still be adhered, making separation difficult. Summary of the invention

[0004] The content of this application is used to introduce concepts in a brief form, which will be described in detail in the detailed implementation section below. The content of this application is not intended to identify the key features or essential features of the technical solution claimed for protection, nor is it intended to limit the scope of the technical solution claimed for protection.

[0005] In order to solve the technical problems mentioned in the above background technology section, some embodiments of the present application provide a three-step stripping device for gallium oxide, including: a pre-cutting unit, used to cut a separation surface on the circumference of a wafer; a laser processing unit, which emits a low-power laser beam, and the laser beam is focused on a focusing plane inside the wafer to form a laser spot; a separation unit, used to pull the wafer parts on both sides of the separation surface in reverse; and a moving unit, used to clamp the wafer and move the wafer to the pre-cutting unit, the laser processing unit and the separation unit in sequence.

[0006] Furthermore, it also includes: a control unit; the control unit is used to control and coordinate the operations of the pre-cutting unit, the laser processing unit, the separation unit and the moving unit.

[0007] Furthermore, the pre-cutting unit includes: a cutting wire and a power module; the cutting wire forms a line contact with the circumference of the wafer, and the power module is connected to the cutting wire and makes the cutting wire rub the circumference of the wafer around the axis of the wafer.

[0008] Furthermore, the power module includes: a power member and a traction line; two ends of the traction line are fixed to two ends of the cutting line in a one-to-one correspondence, the middle of the traction line is fixed to the output end of the power member, and the power member enables the traction line to pull the cutting line.

[0009] Furthermore, two cutting lines are provided, and each cutting line forms a line contact with half of the circumference of the wafer.

[0010] Furthermore, the laser processing unit includes: a laser, an optical scanning module and a focusing module; the laser emits a laser beam to the wafer; the optical scanning module is electrically connected to the laser, and the optical scanning module scans the focal plane of the wafer; the focusing module is placed on the opposite side of the laser, and is used to focus the laser beam into a laser spot on the focal plane.

[0011] Furthermore, the separation unit comprises: a coating module and a pulling module; the coating module covers the wafer parts on both sides of the separation surface with a group of films respectively, and the pulling module clamps the two groups of films and pulls the two groups of films in opposite directions.

[0012] Furthermore, the moving unit includes: a conveying module and a mechanical claw; the mechanical claw fixes the wafer, the mechanical claw is connected to the conveying module, and the conveying module enables the conveying mechanical claw to move to the pre-cutting unit, the laser processing unit and the separation unit in sequence.

[0013] The beneficial effects of this application are:

[0014] The pre-cutting unit cuts the separation surface of the wafer in a circular manner, reducing the circumferential strength of the wafer while reducing the loss of the wafer. The low-power laser emitted by the laser processing unit focuses on the focal plane of the wafer to modify it, reducing the internal strength of the wafer while reducing the micro cracks inside the wafer. Finally, the separation unit can easily separate the wafer into two parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The drawings constituting a part of this application are used to provide a further understanding of this application, so that other features, purposes and advantages of this application become more obvious. The illustrative embodiment drawings and their descriptions of this application are used to explain this application and do not constitute an improper limitation on this application.

[0016] In addition, throughout the drawings, the same or similar reference numerals represent the same or similar elements. It should be understood that the drawings are schematic and that the components and elements are not necessarily drawn to scale.

[0017] In the attached picture:

[0018] Figure 1 It is an overall schematic diagram according to an embodiment of the present application.

[0019] Reference numerals:

[0020] 1. Pre-cutting unit; 11. Power part; 12. Pulling line; 13. Cutting line; 2. Laser processing unit; 21. Laser; 22. Optical scanning module; 23. Focusing module; 31. Laminating module; 311. Laminating controller; 312. Clamping tool; 313. Laminator; 32. Pulling module; 321; Pulling controller; 322. Pulling claw; 4. Moving unit; 41. Conveying module; 42. Mechanical claw; 5. Control unit. DETAILED DESCRIPTION

[0021] Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although certain embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be construed as being limited to the embodiments set forth herein. On the contrary, these embodiments are provided to provide a more thorough and complete understanding of the present disclosure. It should be understood that the drawings and embodiments of the present disclosure are only for exemplary purposes and are not intended to limit the scope of protection of the present disclosure.

[0022] It should also be noted that, for ease of description, only the parts related to the invention are shown in the drawings. In the absence of conflict, the embodiments and features in the embodiments of the present disclosure can be combined with each other.

[0023] It should be noted that the concepts such as "first" and "second" mentioned in the present disclosure are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units.

[0024] It should be noted that the modifications of "one" and "plurality" mentioned in the present disclosure are illustrative rather than restrictive, and those skilled in the art should understand that unless otherwise clearly indicated in the context, it should be understood as "one or more".

[0025] The present disclosure will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0026] Reference Figure 1 ,

[0027] A three-step stripping device for gallium oxide comprises: a pre-cutting unit 1, a laser processing unit 2, a separation unit and a moving unit 4. The pre-cutting unit 1 is a wire cutting machine, which is used to cut a shallow annular separation surface on the circumference of a wafer, and the specific depth is 2% to 5% of the diameter of the wafer, so as to reduce the overall strength of the circumference of the wafer, thereby reducing the power required for the subsequent laser processing unit 2 to emit a laser. The laser processing unit 2 emits a low-power laser beam. In this embodiment, the laser beam is a pulse beam with a wavelength of 310nm to 380nm, a pulse width of less than 50ps, a peak power of the pulse between 50kW and 500kW, and a repetition frequency of more than 100kHz. The laser beam is focused on a focal plane inside the wafer, so that the gallium oxide near the focal plane is thermally modified, so that microcracks are generated inside the wafer to reduce the strength. The separation unit is used to pull the wafer parts on both sides of the separation surface in the opposite direction. Since the circumference of the wafer is cut by the pre-cutting unit 1 and the inside is modified by the laser processing unit 2, the overall strength of the wafer near the separation surface and the focusing plane is reduced, so that the separation unit can easily split the wafer into two. The moving unit 4 is used to clamp the wafer and move the wafer to the pre-cutting unit 1, the laser processing unit 2 and the separation unit in sequence to process the wafer.

[0028] Specifically, it also includes: a control unit 5 . The control unit 5 is an existing PLC control system, which is used to control and coordinate the operations of the pre-cutting unit 1 , the laser processing unit 2 , the separation unit and the moving unit 4 .

[0029] Specifically, the pre-cutting unit 1 includes: a cutting wire 13 and a power module. The cutting wire 13 is a diamond wire, and the cutting wire 13 forms a line contact around the circumference of the wafer. The power module is connected to the cutting wire 13, and the cutting wire 13 rubs the circumference of the wafer at a high speed around the axis of the wafer, thereby cutting a ring-shaped separation surface on the circumference of the wafer.

[0030] Specifically, the power module includes: a power member 11 and a traction line 12. The two ends of the traction line 12 are fixedly wound with the two ends of the cutting line 13 in a one-to-one correspondence. The power member 11 is a motor, and the middle part of the traction line 12 is fixedly wound with the output end of the power member 11. The output end of the power member rotates at a high speed so that the traction line 12 pulls the cutting line 13 to cut.

[0031] Specifically, two cutting lines 13 are provided. Each cutting line 13 forms a line contact with half of the circumference of the wafer, and the two cutting lines 13 are arranged on both sides of the wafer opposite to each other. The two cutting lines 13 cut the wafer synchronously to improve the pre-cutting efficiency.

[0032] Specifically, the laser processing unit 2 includes: a laser 21, an optical scanning module 22 and a focusing module 23. The laser 21 emits a laser beam to the wafer. The optical scanning module 22 is an existing line laser scanner, and the optical scanning module 22 is electrically connected to the laser 21. The optical scanning module 22 scans the focal plane inside the wafer to form a scanning track, and the control system then controls the laser 21 to emit a laser beam, and the laser beam follows the scanning track to irradiate the focal plane. The focusing module 23 is a set of existing mirror groups, and the focusing module 23 is placed on the opposite side of the laser 21, and is used to focus the laser beam into a laser spot on the focal plane. The gallium oxide at the irradiation position of the laser spot heats up and is modified, thereby generating microcracks inside the wafer.

[0033] Specifically, the separation unit includes: a coating module 31 and a pulling module 32. The coating module 31 is an existing wafer coating machine integrated with a coating controller 311, a clamping fixture 312 and a laminator 313. The coating controller 311 controls the clamping fixture 312 to fix the wafer transported by the mobile unit 4, and the coating controller 311 controls the laminator 313 to cover the wafer parts on both sides of the separation surface with a group of films. The pulling module 32 is an existing technical product integrated with a pulling controller 321 and a pulling claw 322. The pulling claw 322 clamps two groups of films, and the pulling controller 321 controls the pulling claw 322 to pull the two groups of films in opposite directions. Since the wafer is relatively fragile near the separation surface and the focusing plane, the two groups of films can easily drive the two parts of the wafer to be divided into two along the separation surface and the focusing plane.

[0034] Specifically, the mobile unit 4 includes: a conveying module 41 and a mechanical claw 42. The mechanical claw 42 is used to clamp the wafer, and the mechanical claw 42 is connected to the conveying module 41. The conveying module 41 adopts an electromagnetic track, and the mechanical claw 42 is fixed to the moving part on the electromagnetic track. The conveying module 41 enables the conveying mechanical claw 42 to move to the pre-cutting unit 1, the laser processing unit 2 and the separation unit in sequence.

[0035] The above descriptions are only some preferred embodiments of the present disclosure and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the embodiments of the present disclosure is not limited to the technical solutions formed by a specific combination of the above-mentioned technical features, but should also cover other technical solutions formed by any combination of the above-mentioned technical features or their equivalent features without departing from the above-mentioned inventive concept. For example, the above-mentioned features are replaced with the technical features with similar functions disclosed in the embodiments of the present disclosure (but not limited to) and the technical solutions formed.

Claims

1. A three-step stripping device for gallium oxide, characterized in that: include: A pre-cutting unit, used for cutting a separation surface around the circumference of the wafer; The laser processing unit emits a low-power laser beam, which is focused on a focusing plane inside the wafer to form a laser spot; A separation unit, used for pulling the wafer portions on both sides of the separation surface in opposite directions; The moving unit is used for clamping the wafer and moving the wafer to the pre-cutting unit, the laser processing unit and the separation unit in sequence.

2. The three-step stripping device for gallium oxide according to claim 1, characterized in that: It also includes: a control unit; the control unit is used to control and coordinate the operations of the pre-cutting unit, the laser processing unit, the separation unit and the moving unit.

3. A three-step stripping device for gallium oxide according to claim 1 or 2, characterized in that: The pre-cutting unit comprises: a cutting line and a power module; the cutting line forms a line contact with the circumference of the wafer, and the power module is connected to the cutting line and makes the cutting line rub the circumference of the wafer around the axis of the wafer.

4. The three-step stripping device for gallium oxide according to claim 3, characterized in that: The power module includes: a power piece and a traction line; two ends of the traction line are fixed to two ends of the cutting line in a one-to-one correspondence, the middle part of the traction line is fixed to the output end of the power piece, and the power piece enables the traction line to pull the cutting line.

5. The three-step stripping device for gallium oxide according to claim 4, characterized in that: Two cutting lines are provided, and each of the cutting lines forms a line contact with half of the circumference of the wafer.

6. A three-step stripping device for gallium oxide according to claim 4 or 5, characterized in that: The laser processing unit includes: a laser, an optical scanning module and a focusing module; the laser emits a laser beam to a wafer; the optical scanning module is electrically connected to the laser, and the optical scanning module scans a focal plane of the wafer; the focusing module is placed on the opposite side of the laser, and is used to focus the laser beam into a laser spot on the focal plane.

7. The three-step stripping device for gallium oxide according to claim 6, characterized in that: The separation unit comprises: a coating module and a pulling module; the coating module covers the wafer parts on both sides of the separation surface with a group of films respectively, and the pulling module clamps the two groups of films and pulls the two groups of films in opposite directions.

8. The three-step stripping device for gallium oxide according to claim 7, characterized in that: The moving unit includes: a conveying module and a mechanical claw; the mechanical claw fixes the wafer, the mechanical claw is connected to the conveying module, and the conveying module enables the conveying mechanical claw to move to the pre-cutting unit, the laser processing unit and the separation unit in sequence.

Images