CN114012917A - Preparation method of gallium oxide single crystal wafer - Google Patents

Preparation method of gallium oxide single crystal wafer Download PDF

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Publication number
CN114012917A
CN114012917A CN202111308106.4A CN202111308106A CN114012917A CN 114012917 A CN114012917 A CN 114012917A CN 202111308106 A CN202111308106 A CN 202111308106A CN 114012917 A CN114012917 A CN 114012917A
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single crystal
gallium oxide
oxide single
crystal wafer
cleavage
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不公告发明人
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Suzhou Liaoyuan Semiconductor Co ltd
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Suzhou Liaoyuan Semiconductor Co ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28D—WORKING STONE OR STONE-LIKE MATERIALS
    • B28D5/00—Fine working of gems, jewels, crystals, e.g. of semiconductor material; apparatus or devices therefor
    • B28D5/0005—Fine working of gems, jewels, crystals, e.g. of semiconductor material; apparatus or devices therefor by breaking, e.g. dicing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B29/00—Machines or devices for polishing surfaces on work by means of tools made of soft or flexible material with or without the application of solid or liquid polishing agents
    • B24B29/02—Machines or devices for polishing surfaces on work by means of tools made of soft or flexible material with or without the application of solid or liquid polishing agents designed for particular workpieces
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B37/00—Lapping machines or devices; Accessories
    • B24B37/04—Lapping machines or devices; Accessories designed for working plane surfaces
    • B24B37/042—Lapping machines or devices; Accessories designed for working plane surfaces operating processes therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28D—WORKING STONE OR STONE-LIKE MATERIALS
    • B28D5/00—Fine working of gems, jewels, crystals, e.g. of semiconductor material; apparatus or devices therefor
    • B28D5/04—Fine working of gems, jewels, crystals, e.g. of semiconductor material; apparatus or devices therefor by tools other than rotary type, e.g. reciprocating tools
    • B28D5/045—Fine working of gems, jewels, crystals, e.g. of semiconductor material; apparatus or devices therefor by tools other than rotary type, e.g. reciprocating tools by cutting with wires or closed-loop blades
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/34—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies not provided for in groups H01L21/0405, H01L21/0445, H01L21/06, H01L21/16 and H01L21/18 with or without impurities, e.g. doping materials
    • H01L21/46—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/428
    • H01L21/461—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/428 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
    • H01L21/463—Mechanical treatment, e.g. grinding, ultrasonic treatment

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  • Mechanical Engineering (AREA)
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  • Condensed Matter Physics & Semiconductors (AREA)
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  • Crystals, And After-Treatments Of Crystals (AREA)
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Abstract

The invention provides a preparation method of a gallium oxide single crystal wafer, which comprises the following steps: providing a gallium oxide single crystal block; cleaving the gallium oxide single crystal ingot to obtain a bulk cleaved structure, the cleaved structure including a cleaved surface and an initial thinning surface opposite to the cleaved surface; thinning the initial thinning surface by taking the cleavage surface as a reference, so that the thinning surface is formed on the initial thinning surface and is parallel to the cleavage surface; and after the thinning surface is formed, cutting the cleavage structure by taking the cleavage surface as a reference to obtain a gallium oxide single crystal wafer with a cutting surface, wherein the cutting surface is parallel to the cleavage surface. The preparation method utilizes the characteristic that the gallium oxide single crystal is easy to be cleaved along the (100) crystal face, obtains the (100) gallium oxide single crystal wafer with a smaller deflection angle on the premise of not needing to be oriented by X rays, has high repeatability, and is beneficial to industrial production.

Description

Preparation method of gallium oxide single crystal wafer
Technical Field
The invention relates to the technical field of wafer preparation, in particular to a preparation method of a gallium oxide single wafer.
Background
β-Ga2O3Single crystals are one of the hottest wide bandgap semiconductor materials currently under study. beta-Ga2O3The ultraviolet cut-off edge of the monocrystal can reach 260nm,the ultraviolet band has high transmittance, and can meet the requirements of the new generation of photoelectric materials on the short wavelength working range. Simultaneously, beta-Ga2O3The single crystal has large forbidden band width, high breakdown field strength, strong radiation resistance and good physical and chemical stability, and is very suitable for developing high-voltage-resistance and high-power semiconductor devices. At present beta-Ga2O3The mainstream process for preparing the single crystal is a die-guiding method, and during the process of processing the crystal prepared by the die-guiding method into the gallium oxide single crystal wafer with a determined crystal face, the cutting is required to be carried out after the X-ray orientation is carried out.
However, beta-Ga prepared by die-casting2O3The thickness of the single crystal is generally less than 6mm, the single crystal has a larger off-angle of a crystal plane, and the off-angle of the crystal plane is generally more than 3 degrees; simultaneously, beta-Ga2O3The single crystal is monoclinic, which results in increased difficulty in crystal orientation. The above reasons make it difficult to obtain a gallium oxide single crystal wafer having a small off-angle.
Disclosure of Invention
Therefore, the technical problem to be solved by the present invention is to overcome the defect that the gallium oxide wafer with a smaller off-angle of crystal plane is not easy to obtain in the prior art, thereby providing a method for preparing a gallium oxide single wafer.
The invention provides a preparation method of a gallium oxide single crystal wafer, which comprises the following steps: providing a gallium oxide single crystal block; cleaving the gallium oxide single crystal ingot to obtain a bulk cleaved structure comprising a cleaved surface and an initial thinning surface opposite to the cleaved surface; thinning the initial thinning surface by taking the cleavage surface as a reference to form a thinning surface on the initial thinning surface, wherein the thinning surface is parallel to the cleavage surface; and after the thinning surface is formed, cutting the cleavage structure by taking the cleavage surface as a reference to obtain a gallium oxide single crystal wafer with a cutting surface, wherein the cutting surface is parallel to the cleavage surface.
Optionally, after cleaving the gallium oxide single crystal ingot, obtaining two cleavage structures; or, a cleavage structure and a cleavage sheet are obtained after cleaving the gallium oxide single crystal ingot.
Optionally, the step of thinning the initial thinning surface with the cleavage surface as a reference includes: fixing the cleavage structure on a thinning platform, wherein the cleavage surface faces the thinning platform; and thinning the initial thinning surface by using a thinning machine.
Optionally, a plurality of the cleavage structures are thinned together.
Optionally, the cleavage structure is cut by a wire cutting process.
Optionally, the step of cutting the cleavage structure by using a wire cutting process includes: fixing the cleavage structure on a cutting platform, wherein the cleavage surface is vertical to the cutting platform; and cutting the cleavage structure by the cutting line.
Optionally, a plurality of the cleavage structures are cut together.
Optionally, the parameters for cutting the cleavage structure by using the wire cutting process include: the diameter of the cutting line is 0.05mm-0.25mm, and the cutting speed of the cutting line is 0.05mm/min-0.6 mm/min.
Optionally, the off-angle of the crystal plane of the gallium oxide single crystal wafer is less than 0.5 °; the thickness of the gallium oxide single crystal wafer is 0.8mm-1 mm.
Optionally, the method for preparing the gallium oxide single crystal wafer further comprises: sequentially carrying out coarse grinding, fine grinding and polishing on the front side of the gallium oxide single crystal wafer; and/or performing coarse grinding, fine grinding and polishing on the back surface of the gallium oxide single crystal wafer in sequence.
Optionally, the roughness of the polished surface of the gallium oxide single crystal wafer is less than 0.5 nm.
Optionally, the parameters for performing rough grinding on the front surface and/or the back surface of the gallium oxide single crystal wafer include: the grain diameter of the abrasive is 8-10 μm, the rotation speed of the grinding disc is 15-25 r/min, and the abrasive comprises alumina grains.
Optionally, the thickness of the gallium oxide single crystal wafer removed by the coarse grinding treatment is 80 μm-130 μm.
Optionally, in the process of performing rough grinding on the gallium oxide single crystal wafer, a plurality of gallium oxide single crystal wafers with the same thickness are uniformly distributed around the center of the grinding disc.
Optionally, the parameters for finely grinding the gallium oxide single crystal wafer include: the grain diameter of the abrasive is 2-5 μm, the rotation speed of the grinding disc is 15-25 r/min, and the abrasive comprises alumina grains.
Optionally, the thickness of the gallium oxide single crystal wafer removed by the fine grinding treatment is 25 μm to 50 μm.
Optionally, in the process of finely grinding the gallium oxide single crystal wafer, a plurality of gallium oxide single crystal wafers with the same thickness are uniformly distributed around the center of the grinding disc.
Optionally, the step of polishing the gallium oxide single crystal wafer comprises: and performing rough polishing and fine polishing on the gallium oxide single crystal wafer in sequence.
Optionally, the polishing pad used for rough polishing is a polyurethane polishing pad, and the polishing pad used for fine polishing is a non-woven fabric polishing pad.
Optionally, the parameters for polishing the gallium oxide single crystal wafer include: the rotating speed of the polishing disc is 20r/min-50r/min, and the polishing solution is silica sol polishing solution; the rough polishing time is 1.5-2.5 h, and the fine polishing time is 2-6 h.
Optionally, the thickness of the gallium oxide single crystal wafer removed by the polishing treatment is 15 μm-20 μm.
Optionally, the gallium oxide single crystal prepared by the mold-guiding method is prepared into the gallium oxide single crystal block by adopting a crystal cutting process.
The technical scheme of the invention has the following advantages:
1. according to the preparation method of the gallium oxide single crystal wafer, provided by the invention, the gallium oxide single crystal is easy to cleave along the (100) crystal face, and the gallium oxide single crystal block is cleaved to obtain a blocky cleavage structure with a cleavage plane, wherein the cleavage plane is the (100) crystal face; thinning the cleavage structure by taking the cleavage surface as a reference to obtain a thinned surface parallel to the cleavage surface, namely the thinned surface is also a (100) crystal surface; and cutting the cleavage structure, wherein the cutting surface is parallel to the cleavage surface, so that the (100) gallium oxide single crystal wafer with a smaller deflection angle is obtained. Namely, the preparation method utilizes the characteristic that the gallium oxide single crystal is easy to be cleaved along the (100) crystal face, obtains the (100) gallium oxide single crystal wafer with a smaller deflection angle on the premise of not needing to be oriented by X rays, has high repeatability, and is beneficial to industrial production.
2. According to the preparation method of the gallium oxide single crystal wafer, the thinning efficiency is effectively improved by thinning a plurality of cleavage structures together.
3. According to the preparation method of the gallium oxide single crystal wafer, the plurality of cleavage structures are cut together, more gallium oxide single crystal wafers can be obtained at one time, and the preparation efficiency of the gallium oxide single crystal wafer is improved.
4. According to the preparation method of the gallium oxide single crystal wafer, the front side and/or the back side of the gallium oxide single crystal wafer are subjected to coarse grinding, so that a surface damage layer generated in a cleavage process and/or a cutting process can be removed; by finely grinding the front surface and/or the back surface of the gallium oxide single crystal wafer, a surface damage layer generated in the coarse grinding process can be removed, and the flatness of the surface of the gallium oxide single crystal wafer is improved, so that subsequent polishing is facilitated; and polishing the front surface and/or the back surface of the gallium oxide single crystal wafer to further improve the surface flatness of the gallium oxide single crystal wafer so as to obtain the gallium oxide single crystal wafer with a high-quality surface, so that the gallium oxide single crystal wafer meets the requirement of subsequent epitaxial use.
5. According to the preparation method of the gallium oxide single crystal wafer, the polishing step comprises rough polishing and fine polishing which are sequentially carried out, the polishing efficiency of the rough polishing is higher than that of the fine polishing, the surface quality after the fine polishing is better than that after the rough polishing, the polishing quality is ensured and the polishing efficiency is improved through the rough polishing and the fine polishing.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
FIG. 1 is a process flow diagram of a method for preparing a single gallium oxide wafer according to an embodiment of the present invention;
FIG. 2 is a schematic view showing a crystal cut of a gallium oxide single crystal into a gallium oxide single crystal ingot according to an embodiment;
FIG. 3 is a schematic diagram of a dicing cleaved structure;
FIG. 4 is a schematic view of arrangement of a plurality of gallium oxide single crystal wafers on a grinding disc during coarse grinding and fine grinding;
description of reference numerals:
1-gallium oxide single crystals; 2-gallium oxide single crystal ingot; 3-cleaving the structure; 4-gallium oxide single crystal wafer; 5-cutting line; 6-grinding disk.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the description of the present invention, it should be noted that the terms "upper", "lower", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, which are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
Referring to fig. 1, the present embodiment provides a method for preparing a gallium oxide single crystal wafer, including:
s1, providing a gallium oxide single crystal block;
s2, cleaving the gallium oxide single crystal block to obtain a block-shaped cleaved structure, wherein the cleaved structure comprises a cleaved surface and an initial thinning surface opposite to the cleaved surface;
s3, thinning the initial thinning surface by taking the cleavage surface as a reference, so that the initial thinning surface forms a thinning surface, wherein the thinning surface is parallel to the cleavage surface;
and S4, after the thinning surface is formed, cutting the cleavage structure by taking the cleavage surface as a reference to obtain a gallium oxide single crystal wafer with a cutting surface, wherein the cutting surface is parallel to the cleavage surface.
According to the preparation method of the gallium oxide single crystal wafer, the gallium oxide single crystal is easy to cleave along the (100) crystal face, and the gallium oxide single crystal block is cleaved to obtain a blocky cleavage structure with a cleavage plane, wherein the cleavage plane is the (100) crystal face; thinning the cleavage structure by taking the cleavage surface as a reference to obtain a thinned surface parallel to the cleavage surface, namely the thinned surface is also a (100) crystal surface; and cutting the cleavage structure, wherein the cutting surface is parallel to the cleavage surface, so that the (100) gallium oxide single crystal wafer with a smaller deflection angle is obtained. Namely, the preparation method utilizes the characteristic that the gallium oxide single crystal is easy to be cleaved along the (100) crystal face, obtains the (100) gallium oxide single crystal wafer with a smaller deflection angle on the premise of not needing to be oriented by X rays, has high repeatability, and is beneficial to industrial production.
It is understood that a large number of micron-sized large steps exist on the surface of the gallium oxide single crystal wafer prepared only by cleavage, the surface flatness of the single crystal wafer is extremely poor, and the surface warpage is large, so that the requirement of subsequent epitaxy cannot be met.
The method for preparing a gallium oxide single crystal wafer provided by the embodiment further comprises the following steps:
s5, performing coarse grinding on the front surface and/or the back surface of the gallium oxide single crystal wafer;
s6, finely grinding the front surface and/or the back surface of the gallium oxide single crystal wafer;
and S7, polishing the front surface and/or the back surface of the gallium oxide single crystal wafer.
According to the preparation method of the gallium oxide single crystal wafer, the surface damage layer generated in the cleavage process and/or the cutting process can be removed by performing coarse grinding on the front surface and/or the back surface of the gallium oxide single crystal wafer; by finely grinding the front surface and/or the back surface of the gallium oxide single crystal wafer, a surface damage layer generated in the coarse grinding process can be removed, and the flatness of the surface of the gallium oxide single crystal wafer is improved, so that subsequent polishing is facilitated; and polishing the front surface and/or the back surface of the gallium oxide single crystal wafer to further improve the surface flatness of the gallium oxide single crystal wafer so as to obtain the gallium oxide single crystal wafer with a high-quality surface, so that the gallium oxide single crystal wafer meets the requirement of subsequent epitaxial use.
The method for preparing the gallium oxide single crystal wafer provided by the present example is clearly and completely described below with reference to fig. 2 to 4.
In step S1, a gallium oxide single crystal ingot is provided.
Specifically, referring to fig. 2, a large-size sheet-shaped gallium oxide single crystal 1 prepared by a die-guiding method is prepared into a gallium oxide single crystal block 2 by using a crystal cutting process. The thickness of the gallium oxide single crystal 1 prepared by the die-guiding method is less than or equal to 6mm, the deflection angle is more than 3 degrees, and the gallium oxide single crystal 1 is beta-Ga2O3(100) A single crystal. The shape of the (100) crystal plane of gallium oxide single crystal block 2 includes, but is not limited to, a rectangle or a square. When the shape of the (100) plane of the gallium oxide single crystal block 2 is a square, the side length of the square includes, but is not limited to, 10mm, 15mm, or 20 mm.
In step S2, the gallium oxide single crystal ingot 2 is cleaved to obtain a bulk cleaved structure including a cleavage plane and an initial thinning plane opposite to the cleavage plane.
Specifically, the side face of the gallium oxide single crystal ingot 2, which is not the (100) crystal face, is hit by a sharp cutter.
When the knocking position is located at the edge of the side face of the gallium oxide single crystal block 2, a cleavage sheet is easy to fall off from the gallium oxide single crystal block 2, so that a cleavage structure with a cleavage plane and a cleavage sheet with the cleavage plane are obtained, the thickness of the cleavage structure is larger than that of the cleavage sheet, and the cleavage plane is a flat (100) crystal plane. Further, the thickness of the cleavage sheet is 200 μm to 800 μm. Illustratively, the thickness of the cleavage sheet may be 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, or 800 μm. It should be understood that when several gallium oxide single crystal blocks 2 are cleaved, the thickness of the cleaved structures may be different, since the tap positions are not easily consistent, and the difference between the thicknesses of the several cleaved structures is 0 μm-600 μm.
When the tapping position is close to the middle of the side face of the gallium oxide single crystal ingot 2, the gallium oxide single crystal ingot 2 is easily separated into two cleavage structures having cleavage planes. It is to be understood that the thickness of the cleavage structure is greater than 800 μm.
Preferably, the tapping position is located at the edge of the side face of the gallium oxide single crystal ingot 2, so that the gallium oxide single crystal ingot 2 can realize the orientation of the gallium oxide wafer only by losing less than 1mm of thickness (i.e., the thickness of the cleavage sheet), and the yield of the gallium oxide single crystal wafer can be improved.
It should be understood that the thickness of the cleavage structure described in the present embodiment refers to the dimension of the cleavage structure in the direction perpendicular to the cleavage plane.
In step S3, the initial thinning surface is thinned with the cleavage surface as a reference, so that the initial thinning surface forms a thinning surface, and the thinning surface is parallel to the cleavage surface.
Specifically, the step of thinning the initial thinning surface with the cleavage surface as a reference includes: fixing the cleavage structure on a thinning platform, wherein the cleavage surface faces the thinning platform; and thinning the initial thinning surface by using a thinning machine. The thinning platform includes, but is not limited to, a circular glass disk.
As a preferred embodiment, a plurality of the cleavage structures may be thinned together to effectively improve the thinning efficiency. And after the thinning is finished, the thicknesses of the cleavage structures are the same.
In step S4, referring to fig. 3, after the thinning surface is formed, the cleavage structure 3 is cut with the cleavage surface as a reference to obtain a gallium oxide single crystal wafer having a cut surface parallel to the cleavage surface.
Specifically, referring to fig. 3, the cleavage structure 3 is cut by a wire cutting process. The step of cutting the cleavage structure 3 by using a wire cutting process includes: fixing the cleavage structure 3 on a cutting platform, wherein the cleavage plane is perpendicular to the cutting platform; the cleavage structure 3 is cut by a cutting line 5, and a cut surface is formed by running the cutting line 5 in the cleavage structure 3. And a group of cutting surfaces can be obtained by one-time operation of the cutting line 5 in the cleavage structure 3, and a plurality of gallium oxide single crystal wafers can be obtained by multiple times of operation of the cutting line 5 along the [001] crystal direction of the cleavage structure 3. The direction of extension of the cutting lines 5 is parallel to the [010] crystal direction of the cleavage structure 3.
Further, the cutting line 5 includes, but is not limited to, a diamond wire, the diameter of the cutting line 5 is 0.05mm to 0.25mm, and the cutting rate of the cutting line 5 is 0.05mm/min to 0.6 mm/min. Illustratively, the diameter of the cutting line 5 may be 0.05mm, 0.1mm, 0.15mm, 0.2mm or 0.25mm, and the cutting rate of the cutting line 5 may be 0.05mm/min, 0.1mm/min, 0.15mm/min, 0.2mm/min, 0.25mm/min, 0.3mm/min, 0.35mm/min, 0.4mm/min, 0.45mm/min, 0.5mm/min, 0.55mm/min or 0.6 mm/min. By limiting the diameter of the cutting line 5 to the above-mentioned value, on the one hand, the strength of the cutting line 5 is ensured so that the cutting line 5 can smoothly perform cutting operation, and on the other hand, cutting loss can be controlled. By limiting the cutting rate of the cutting line 5 to the above values, it is advantageous to ensure the cutting effect of the cleaving structure 3.
Furthermore, the thickness of the gallium oxide single crystal wafer obtained by cutting is 0.8mm-1 mm. Illustratively, the thickness of the gallium oxide single crystal wafer may be 0.8mm, 0.9mm, or 1 mm. The gallium oxide single crystal wafer is easy to crack in the cutting process when the thickness of the gallium oxide single crystal wafer is too small, and the number of the slices is small when the thickness of the gallium oxide single crystal wafer is too large. By limiting the thickness of the gallium oxide single crystal wafer to the above value, the number of slices can be ensured on the basis of ensuring the yield of the gallium oxide single crystal wafer, and specifically, 5 gallium oxide single crystal wafers can be cut out from the gallium oxide single crystal block 2 with the thickness of 6mm at most.
It should be understood that the thickness of the gallium oxide single crystal wafer described in the present embodiment refers to the dimension of the gallium oxide single crystal wafer in the direction perpendicular to the (100) crystal plane.
Further, with reference to fig. 3, a plurality of the cleavage structures 3 may be cut together, so that a plurality of single gallium oxide wafers can be obtained at one time, and the preparation efficiency of the single gallium oxide wafers is improved. Specifically, a plurality of the cleavage structures 3 are fixed on a cutting platform, and cleavage surfaces of the cleavage structures 3 are parallel to each other and perpendicular to the cutting platform. In a preferred embodiment, referring to fig. 3, the cleavage structures 3 have the same thickness and are sequentially arranged along the first direction to form a cleavage structure group, and the cleavage surfaces of the cleavage structures 3 in the same cleavage structure group are located in a plane, so that when the cutting line 5 runs, the cleavage structures 3 in the cleavage structure group can be cut simultaneously. Furthermore, a plurality of cleavage structure groups can be arranged on the cutting platform, and adjacent cleavage structure groups are arranged in parallel at intervals, so that a cleavage structure array is formed.
In step S5, the front and/or back of the single-crystal gallium oxide wafer is subjected to rough grinding.
Specifically, referring to fig. 4, rough grinding is performed by placing the front and/or back surface of the gallium oxide single crystal wafer 4 on an abrasive disk 6, the surface of which is coated with an abrasive. The parameters for rough grinding the front and/or back of the gallium oxide single-crystal wafer 4 include: the grain size of the abrasive is 8-10 μm, the rotating speed of the grinding disc 6 is 15-25 r/min, the thickness of the gallium oxide single crystal wafer 4 removed by the coarse grinding treatment is 80-130 μm, and the abrasive includes but is not limited to alumina grains. Illustratively, the grain size of the abrasive can be 8 μm, 9 μm or 10 μm, the rotation speed of the grinding disc 6 can be 15r/min, 16r/min, 17r/min, 18r/min, 19r/min, 20r/min, 21r/min, 22r/min, 23r/min, 24r/min or 25r/min, and the thickness of the gallium oxide single crystal wafer 4 removed by the coarse grinding treatment can be 80 μm, 90 μm, 100 μm, 110 μm, 120 μm or 130 μm.
As a preferred embodiment, as shown in fig. 4, during the coarse grinding of the gallium oxide single crystal wafer 4, a plurality of gallium oxide single crystal wafers 4 with the same thickness may be uniformly arranged around the center of the grinding disc 6, so as to not only improve the coarse grinding efficiency, but also ensure the specific same coarse grinding effect of the plurality of gallium oxide single crystal wafers 4, and ensure the uniformity of the coarse grinding effect.
It should be understood that a part of the gallium oxide single crystal wafer 4 has a cleavage plane and a cutting plane which are oppositely arranged, the front surface of the gallium oxide single crystal wafer 4 is one of the cleavage plane and the cutting plane, and the other is the back surface of the gallium oxide single crystal wafer 4; part of the gallium oxide single crystal wafer 4 is provided with a thinning surface and a cutting surface which are oppositely arranged, the front surface of the gallium oxide single crystal wafer 4 is one of the thinning surface and the cutting surface, and the other is the back surface of the gallium oxide single crystal wafer 4; the partial gallium oxide single crystal wafer 4 has two cutting surfaces which are oppositely arranged, and the two cutting surfaces are the front surface and the back surface of the gallium oxide single crystal wafer 4 respectively.
In step S6, the front and/or back of the single-crystal gallium oxide wafer is finely ground.
Specifically, referring to fig. 4, fine grinding is performed by placing the surface of the gallium oxide single crystal wafer 4 subjected to the rough grinding process on a grinding plate 6, the surface of which is coated with an abrasive. The parameters for finely grinding the gallium oxide single crystal wafer 4 include: the grain size of the abrasive is 2-5 μm, the rotating speed of the grinding disc 6 is 15-25 r/min, the thickness of the gallium oxide single crystal plate 4 removed by the fine grinding treatment is 25-50 μm, and the abrasive comprises but is not limited to alumina grains. Illustratively, the grain size of the abrasive can be 2 μm, 3 μm, 4 μm or 5 μm, the rotation speed of the grinding disc 6 can be 15r/min, 16r/min, 17r/min, 18r/min, 19r/min, 20r/min, 21r/min, 22r/min, 23r/min, 24r/min or 25r/min, and the thickness of the gallium oxide single crystal plate 4 removed by the fine grinding treatment can be 25 μm, 30 μm, 35 μm, 40 μm, 45 μm or 50 μm.
As a preferred embodiment, as shown in fig. 4, in the process of fine grinding the gallium oxide single crystal wafer 4, a plurality of gallium oxide single crystal wafers 4 with the same thickness may be uniformly arranged around the center of the grinding disc 6, so as to not only improve the fine grinding efficiency, but also ensure the specific same fine grinding effect of the plurality of gallium oxide single crystal wafers 4, and ensure the uniformity of the fine grinding effect.
In step S7, the front surface and/or the back surface of the gallium oxide single crystal wafer 4 is polished.
Specifically, the surface of the gallium oxide single crystal wafer 4 subjected to the fine grinding treatment is polished. The step of polishing the gallium oxide single crystal wafer 4 includes: and performing rough polishing and fine polishing on the gallium oxide single crystal wafer 4 in sequence. The polishing efficiency of rough polishing is higher than that of fine polishing, the surface quality after fine polishing is better than that after rough polishing, and the polishing quality is ensured and the polishing efficiency is improved by firstly rough polishing and then fine polishing. .
Further, the polishing pad adopted by rough polishing is a polyurethane polishing pad, and the time of rough polishing is 1.5h-2.5 h; the polishing pad adopted by the fine polishing is a non-woven fabric polishing pad, and the fine polishing time is 2-6 h; in the polishing process, the rotating speed of the polishing disc is 20r/min-50r/min, the polishing solution is silica sol polishing solution, and the pH value of the polishing solution is 4-5; the thickness of the gallium oxide single crystal wafer 4 removed by the polishing treatment is 15-20 μm. Illustratively, the time of the rough polishing can be 1.5h, 2h or 2.5h, the time of the fine polishing can be 2h, 3h, 4h, 5h or 6h, the rotation speed of a polishing disc can be 20r/min, 30r/min, 40r/min or 50r/min, and the thickness of the gallium oxide single crystal wafer 4 removed by the polishing treatment can be 15 μm, 16 μm, 17 μm, 18 μm, 19 μm or 20 μm. It is understood that the weakly acidic silica sol polishing solution can reduce the chemical corrosion of the polishing solution to the gallium oxide single crystal wafer, avoid the gallium oxide single crystal wafer from being partially over-corroded, and is beneficial to obtaining the single crystal wafer with good surface quality.
It is to be understood that a single-sided polishing sheet can be obtained by roughly grinding the front and/or back surface of the gallium oxide single crystal wafer 4, and successively finely grinding and polishing the roughly ground surface; the front side and the back side of the gallium oxide single crystal wafer 4 are respectively and sequentially subjected to coarse grinding, fine grinding and polishing, so that a double-sided polished wafer can be obtained.
By the preparation method of the gallium oxide single crystal wafer provided by the embodiment, the gallium oxide single crystal wafer 4 with the thickness of 0.8mm-1mm, the roughness of less than 0.5nm and the crystal plane deflection angle of less than 0.5 degrees can be obtained.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.

Claims (10)

1. A method for preparing a gallium oxide single crystal wafer is characterized by comprising the following steps:
providing a gallium oxide single crystal block;
cleaving the gallium oxide single crystal ingot to obtain a bulk cleaved structure comprising a cleaved surface and an initial thinning surface opposite to the cleaved surface;
thinning the initial thinning surface by taking the cleavage surface as a reference to form a thinning surface on the initial thinning surface, wherein the thinning surface is parallel to the cleavage surface;
and after the thinning surface is formed, cutting the cleavage structure by taking the cleavage surface as a reference to obtain a gallium oxide single crystal wafer with a cutting surface, wherein the cutting surface is parallel to the cleavage surface.
2. The method for preparing a gallium oxide single crystal wafer according to claim 1, wherein two cleavage structures are obtained after cleaving the gallium oxide single crystal ingot; or, a cleavage structure and a cleavage sheet are obtained after cleaving the gallium oxide single crystal ingot.
3. The method for producing a single crystal wafer of gallium oxide according to claim 1 or 2, wherein the step of thinning the initial thinning plane with respect to the cleavage plane comprises:
fixing the cleavage structure on a thinning platform, wherein the cleavage surface faces the thinning platform;
thinning the initial thinning surface by using a thinning machine;
preferably, a plurality of the cleavage structures are thinned together.
4. The method for producing a gallium oxide single crystal wafer according to claim 1 or 2, wherein the cleavage structure is cut by a wire cutting process;
preferably, the step of cutting the cleavage structure by using a wire cutting process includes: fixing the cleavage structure on a cutting platform, wherein the cleavage surface is vertical to the cutting platform; cutting the cleavage structure by a cutting line;
preferably, a plurality of the cleavage structures are cut together;
preferably, the parameters for cutting the cleavage structure by the wire cutting process include: the diameter of the cutting line is 0.05mm-0.25mm, and the cutting speed of the cutting line is 0.05mm/min-0.6 mm/min.
5. The method for producing a gallium oxide single crystal wafer according to claim 1 or 2, wherein the off-plane angle of the gallium oxide single crystal wafer is less than 0.5 °; the thickness of the gallium oxide single crystal wafer is 0.8mm-1 mm.
6. The method for producing a gallium oxide single crystal wafer according to claim 1 or 2, further comprising: sequentially carrying out coarse grinding, fine grinding and polishing on the front side of the gallium oxide single crystal wafer; and/or, carrying out coarse grinding, fine grinding and polishing on the back surface of the gallium oxide single crystal wafer in sequence;
preferably, the roughness of the surface of the gallium oxide single crystal wafer after polishing is less than 0.5 nm.
7. The method for preparing the gallium oxide single crystal wafer according to claim 6, wherein the parameters for rough grinding of the front and/or back surface of the gallium oxide single crystal wafer include: the grain diameter of the abrasive is 8-10 μm, the rotating speed of the grinding disc is 15-25 r/min, and the abrasive comprises alumina grains;
preferably, the thickness of the gallium oxide single crystal wafer removed by the coarse grinding treatment is 80-130 μm;
preferably, during the coarse grinding of the gallium oxide single crystal wafer, a plurality of gallium oxide single crystal wafers with the same thickness are uniformly distributed around the center of the grinding disc.
8. The method for preparing a gallium oxide single crystal wafer according to claim 6, wherein the parameters for finely grinding the gallium oxide single crystal wafer include: the grain diameter of the abrasive is 2-5 μm, the rotating speed of the grinding disc is 15-25 r/min, and the abrasive comprises alumina grains;
preferably, the thickness of the gallium oxide single crystal wafer removed by the fine grinding treatment is 25-50 μm;
preferably, during the fine grinding process of the gallium oxide single crystal wafer, a plurality of gallium oxide single crystal wafers with the same thickness are uniformly distributed around the center of the grinding disc.
9. The method for preparing a gallium oxide single crystal wafer according to claim 6, wherein the step of polishing the gallium oxide single crystal wafer comprises: carrying out rough polishing and fine polishing on the gallium oxide single crystal wafer in sequence;
preferably, the polishing pad used for rough polishing is a polyurethane polishing pad, and the polishing pad used for fine polishing is a non-woven fabric polishing pad;
preferably, the parameters for polishing the gallium oxide single crystal wafer comprise: the rotating speed of the polishing disc is 20r/min-50r/min, and the polishing solution is silica sol polishing solution; the rough polishing time is 1.5-2.5 h, and the fine polishing time is 2-6 h;
preferably, the thickness of the gallium oxide single crystal wafer removed by the polishing treatment is 15 μm-20 μm.
10. The method for producing a gallium oxide single crystal wafer according to claim 1 or 2, wherein the gallium oxide single crystal mass is produced from a gallium oxide single crystal produced by a die-guided method by a crystal cutting process.
CN202111308106.4A 2021-11-05 2021-11-05 Preparation method of gallium oxide single crystal wafer Pending CN114012917A (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009091212A (en) * 2007-10-10 2009-04-30 Nippon Light Metal Co Ltd Gallium oxide single crystal substrate and its manufacture method
WO2013054917A1 (en) * 2011-10-13 2013-04-18 株式会社タムラ製作所 Semiconductor element and manufacturing method thereof
CN110265346A (en) * 2019-05-31 2019-09-20 浙江荷清柔性电子技术有限公司 The processing method of wafer
CN111546136A (en) * 2020-04-30 2020-08-18 济南晶正电子科技有限公司 Method for polishing end face of wafer without cleavage face
CN112665943A (en) * 2020-12-31 2021-04-16 山东大学 Method for rapidly detecting subsurface damage of gallium oxide crystal

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009091212A (en) * 2007-10-10 2009-04-30 Nippon Light Metal Co Ltd Gallium oxide single crystal substrate and its manufacture method
WO2013054917A1 (en) * 2011-10-13 2013-04-18 株式会社タムラ製作所 Semiconductor element and manufacturing method thereof
CN110265346A (en) * 2019-05-31 2019-09-20 浙江荷清柔性电子技术有限公司 The processing method of wafer
CN111546136A (en) * 2020-04-30 2020-08-18 济南晶正电子科技有限公司 Method for polishing end face of wafer without cleavage face
CN112665943A (en) * 2020-12-31 2021-04-16 山东大学 Method for rapidly detecting subsurface damage of gallium oxide crystal

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