CN-122007677-A - Method and device for modifying hard and brittle material through pulse laser

CN122007677ACN 122007677 ACN122007677 ACN 122007677ACN-122007677-A

Abstract

The invention relates to a method and a device for modifying a hard and brittle material by pulse laser, comprising the following steps of S1, fixing a hard and brittle material crystal ingot on a three-dimensional moving platform, S2, focusing a laser focus at a height above the bottom of the crystal ingot 0 The laser is controlled to scan on the same plane to form continuous and uniform transverse modified layer inside the crystal ingot, S3, the crystal ingot is peeled off along the modified layer by applying external force, S4, the focus of the laser is moved upwards to a height Wherein , In order to obtain the thickness of the modified layer on the surface of the stripping surface according to the actual measurement after the interaction of the laser and the material in the previous stripping cycle, S5, repeating the scanning and stripping steps in the steps S2-S4 until the slicing of the ingot layer by layer is completed.

Inventors

WEN QIULING
LIU SA
HUANG HUI
WU MIN
HU ZHONGWEI
HUANG GUOQIN

Assignees

华侨大学

Dates

Publication Date: 20260512
Application Date: 20260228

Claims (6)

1. A method of modifying a hard brittle material by a pulsed laser comprising the steps of: S1, fixing a hard and brittle material ingot on a three-dimensional moving platform; s2, focusing the laser focus at a height above the bottom of the ingot 0 The laser is controlled to scan on the same plane, and a continuous and uniform transverse modified layer is formed inside the ingot; S3, peeling the ingot along the modified layer by applying an external force; S4, moving the focus of the laser upwards by a height Wherein , In order to obtain the thickness of the modified layer on the surface of the stripping surface according to the actual measurement after the interaction of the laser and the material in the previous stripping cycle, The thickness of the modified layer is the thickness of the laser slice Real-time measurement is carried out through an online optical coherence tomography module integrated in a processing light path; s5, repeating the scanning and stripping steps in the steps S2-S4 until the slicing of the ingot layer by layer is completed.
2. The method for modifying a hard brittle material by a pulsed laser according to claim 1, wherein the distance between the material to be processed and the laser focus is set by elevating and lowering the objective lens before processing, and the laser focus is set above the bottom of the material to be processed Where the said Is the distance between the laser focus and the bottom of the ingot, when the first laser modification is carried out Set to the wafer target lift-off thickness delta.
3. The method according to claim 1, wherein the laser focus is shaped into a flat focus in the transverse direction by means of an adaptive optics in S2, so that the material is modified in the transverse direction, and a continuous transverse modified layer is formed inside the material.
4. The method of claim 1, wherein the external force applied in S3 is any one of mechanical force, thermal stress, sonic energy, or electrochemical energy.
5. The method of claim 1, wherein the S1 hard brittle material is one of diamond, silicon carbide, silicon, glass, fused quartz, gallium nitride, gallium oxide, sapphire, aluminum nitride, yttrium aluminum garnet, spinel.
6. An apparatus for modifying a hard brittle material by pulse laser, characterized in that the method for modifying a hard brittle material by pulse laser according to any one of claims 1 to 5 is adopted, and comprises a computer system, a laser, a beam expander, an adaptive optical element, a reflecting mirror, a three-dimensional moving platform for fixing and moving an ingot of the hard brittle material, and an on-line optical coherence tomography module, wherein the computer system controls the movement of the laser and the three-dimensional moving platform, the laser emitted from the laser is subjected to beam shaping by the beam expander and the adaptive optical element and is focused in a laser transverse modification area in the ingot of the hard brittle material after being reflected by the reflecting mirror, and the on-line optical coherence tomography module can reconstruct a two-dimensional or three-dimensional microstructure profile of the inside of a sample in real time, and the computer system automatically recognizes and calculates the average thickness of a modified layer of a peeling surface by analyzing the profile.

Description

Method and device for modifying hard and brittle material through pulse laser Technical Field The invention belongs to the technical field of precision machining, and particularly relates to a laser slicing method for a hard and brittle material. Background In the prior art, laser is adopted to carry out internal modification slicing on a hard and brittle material ingot, the technology focuses a high-energy laser beam into the hard and brittle material, in the process, the physical and chemical changes induced by the laser change can change the material characteristics of a laser irradiation area, so that defects such as holes, cracks and the like are generated, a large-area transverse modification area is formed at a specific position in the material through continuous scanning of the laser, a foundation is laid for subsequent separation of wafers, and then separation of the material is realized by means of external force or other forms of energy. The whole process does not damage the crystal surface structure, has the advantages of high efficiency, high precision, small thermal damage and the like, and is particularly suitable for slicing the thin wafer made of the hard and brittle materials. In the prior art, ultra-fast laser is focused at a certain depth inside a hard brittle material to induce local modified layers or micro-cavities, and then stripping is completed along a preset path under the action of subsequent external force. However, the laser internal modification slicing methods proposed in these patents utilize laser to scan and modify the material layer by layer from top to bottom to strip, after each layer of scan and modify is completed, the wafer is separated along the modified layer by external force or other forms of energy, then the laser focus moves down, and the next modified layer is formed by continuous scanning, so that the process is circulated until the whole ingot is sliced. However, in this method, after the ingot is peeled once, a modified layer remains on the surface of the peeled ingot, and the peeled ingot has a high surface roughness, which hinders the transmission of subsequent laser light, and if the internal modification peeling is to be performed again, it is necessary to grind and remove the modified layer on the surface, and the modified layer on the surface is prevented from preventing the subsequent laser light from transmitting the ingot for internal modification, so that this method requires a subsequent grinding step, and increases the processing and time costs. Disclosure of Invention In order to solve the technical problems, the invention provides a method for modifying a hard and brittle material by pulse laser, which concretely adopts the following technical scheme that the method for modifying the hard and brittle material by the pulse laser comprises the following steps: S1, fixing a hard and brittle material ingot on a three-dimensional moving platform; s2, focusing the laser focus at a height above the bottom of the ingot The laser is controlled to scan on the same plane, and a continuous and uniform transverse modified layer is formed inside the ingot; S3, peeling the ingot along the modified layer by applying an external force; S4, moving the focus of the laser upwards by a height Wherein,In order to obtain the thickness of the modified layer on the surface of the stripping surface according to the actual measurement after the interaction of the laser and the material in the previous stripping cycle,The thickness d of the modified layer is obtained by real-time measurement through an on-line optical coherence tomography module (10) integrated in a processing light path for the thickness of the laser slice. The device integrates an on-line optical coherence tomography module, and can reconstruct a two-dimensional or three-dimensional microstructure section view of the interior of a sample in real time. By analyzing the sectional view, the computer system (1) can automatically identify and calculate the average thickness d of the peeling surface deterioration layer (such as micro-crack area and amorphization area), and the laser slice thickness delta is the preset target peeling thickness of the single wafer. S5, repeating the scanning and stripping steps in the steps S2-S4 until the slicing of the ingot layer by layer is completed. Preferably, the distance between the material to be processed and the laser focus is set by lifting the objective lens before processing, and the laser focus is arranged above the bottom of the material to be processedWhere the saidIs the distance between the laser focus and the bottom of the ingot, when the first laser modification is carried outSet to the target lift-off thickness of the wafer。 Preferably, in the step S2, the laser focus is shaped into a flat focus along the transverse direction by the adaptive optical element, so that the material is modified along the transverse direction, and finally a continuous transve