Cutting method of multi-wire saw for sapphire crystal rod and multi-wire saw

Abstract

The present invention provides a cutting method and multi-wire sawing machine for sapphire crystal ingots. The method comprises: securing a sapphire crystal ingot to an ingot fixture of the multi-wire sawing machine, aligning the end face of the sapphire crystal ingot to be cut parallel to the cutting direction of the cutting wires; moving the sapphire crystal ingot vertically toward the cutting wires, rotating a guide wheel wrapped with multiple cutting wires, and spraying a cooling medium onto the surface of the sapphire crystal ingot via a cooling device. The cooling medium comprises a water-based cutting fluid and an alkaline compound. The rotation of the guide wheel causes the cutting wires to reciprocate to cut the sapphire crystal ingot. The flow rate of the alkaline compound sprayed per unit volume at the first end of the sapphire crystal ingot is greater than the flow rate of the alkaline compound sprayed per unit volume at the second end. This cutting method and multi-wire sawing machine can reduce differences in wafer warpage caused by inconsistent cutting capabilities between the inlet and outlet wire ends.

Description

Technical Field

[0001] The present invention relates to the technical field of sapphire wafer manufacturing, and in particular to a cutting method and a multi-wire saw for a sapphire crystal rod. Background Art

[0002] As a high-precision device for processing brittle and hard materials, multi-wire saws utilize a high-speed reciprocating cutting wire, which draws abrasive material into the processing area (or the cutting wire itself becomes attached to the abrasive material), grinding the workpiece to achieve the desired cut. This cutting method utilizes abrasive grinding, a physical cold working method that does not affect the properties of the material being cut. Due to this characteristic, multi-wire saws are widely used for high-precision cutting of materials such as magnetic materials, sapphire, solar wafers, and crystal.

[0003] When using a multi-wire saw to cut sapphire ingots into sapphire wafers, existing cutting methods use wires at the inlet end of the machine that have a greater cutting capacity than the outlet end. This results in inconsistent warpage across multiple wafers cut from the same ingot, leading to significant morphological differences among the wafers and, consequently, low wafer yields. Therefore, reducing the warpage differences among wafers cut from the same ingot to improve the consistency of their morphology is a pressing technical issue. Summary of the Invention

[0004] In view of this, the present invention provides a cutting method and a multi-wire saw for a sapphire crystal rod to solve one or more problems existing in the prior art.

[0005] According to one aspect of the present invention, a cutting method for a multi-wire sawing machine for a sapphire crystal ingot is disclosed, the method comprising:

[0006] Fixing the sapphire crystal ingot on the crystal ingot fixing device of the multi-wire sawing machine, and making the end face of the sapphire crystal ingot to be cut parallel to the cutting direction of the cutting wire;

[0007] The sapphire crystal rod is moved vertically toward the cutting wires, a guide wheel wrapped with multiple cutting wires is rotated, and a cooling medium is sprayed onto the surface of the sapphire crystal rod through a cooling device. The components of the cooling medium include water-based cutting fluid and alkaline compounds. The rotation of the guide wheel causes the cutting wires to reciprocate to cut the sapphire crystal rod; wherein the flow rate of the alkaline compound sprayed per unit volume at the first end of the sapphire crystal rod is greater than the flow rate of the alkaline compound sprayed per unit volume at the second end of the sapphire crystal rod. The first end of the sapphire crystal rod is cut by the multiple cutting wires close to the wire entry end, and the second end of the sapphire is cut by the multiple cutting wires close to the wire exit end.

[0008] In some embodiments of the present invention, the alkaline compound is potassium hydroxide or sodium hydroxide; and / or

[0009] The cooling medium is formed by mixing the water-based cutting fluid and the alkaline compound.

[0010] In some embodiments of the present invention, when the alkaline compound is potassium hydroxide, the volume ratio of the water-based cutting fluid to potassium hydroxide in the cooling medium ranges from 10:1 to 20:1.

[0011] In some embodiments of the present invention, the volume ratio of water-based cutting fluid to potassium hydroxide in the cooling medium is 20:1.

[0012] In some embodiments of the present invention, a ratio of a flow rate of the alkaline compound sprayed per unit volume at the first end of the sapphire crystal rod to a flow rate of the alkaline compound sprayed per unit volume at the second end of the sapphire crystal rod ranges from 4:1 to 3:2.

[0013] In some embodiments of the present invention, the flow rate of the alkaline compound sprayed per unit volume of the sapphire crystal rod gradually decreases from the first end to the second end.

[0014] According to another aspect of the present invention, a multi-wire saw for sapphire crystal rods is disclosed. The multi-wire saw adopts the cutting method of the multi-wire saw for sapphire crystal rods described in any of the above embodiments when cutting sapphire crystal rods.

[0015] In some embodiments of the present invention, the cooling device includes a plurality of nozzles spaced apart along the length direction of the crystal ingot.

[0016] In some embodiments of the present invention, a distance between any two adjacent nozzles near the second end of the sapphire crystal rod is 1.5 to 4 times a distance between any two adjacent nozzles near the first end of the sapphire crystal rod.

[0017] In some embodiments of the present invention, the distance between two adjacent nozzles gradually increases from the first end to the second end of the sapphire crystal rod.

[0018] The present invention discloses a cutting method and a multi-wire saw for a sapphire crystal rod. A cooling medium comprising a water-based cutting fluid and an alkaline compound is sprayed onto the sapphire crystal rod to soften the sapphire crystal rod, thereby facilitating multi-wire sawing of the sapphire crystal rod. In addition, the flow rate of the alkaline compound sprayed per unit volume at the first end of the sapphire crystal rod is greater than the flow rate of the alkaline compound sprayed per unit volume at the second end of the sapphire crystal rod. This results in a higher degree of softening of the sapphire crystal rod at the wire entry end than at the wire exit end, thereby reducing the warpage of the wafer at the wire entry end and minimizing the difference in warpage of each wafer caused by inconsistent cutting capabilities at the wire entry and wire exit ends, thereby maintaining substantially consistent morphologies of each wafer.

[0019] Additional advantages, objects, and features of the present invention will be set forth in part in the following description and will in part become apparent to those skilled in the art upon examination of the following or may be learned by practice of the present invention. The objects and other advantages of the present invention may be realized and attained by the structure particularly pointed out in the written description and claims thereof as well as in the accompanying drawings.

[0020] Those skilled in the art will understand that the purposes and advantages that can be achieved by the present invention are not limited to the above specific descriptions, and the above and other purposes that can be achieved by the present invention will be more clearly understood based on the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings described herein are intended to provide a further understanding of the present invention, constitute a part of this application, and do not constitute a limitation of the present invention. The components in the drawings are not drawn to scale, but are merely for the purpose of illustrating the principles of the present invention. To facilitate the illustration and description of certain portions of the present invention, corresponding portions in the drawings may be exaggerated, that is, may be larger than other components in an exemplary device actually manufactured according to the present invention. In the drawings:

[0022] Figure 1 The figure is a flow chart of a cutting method of a multi-wire saw for a sapphire crystal ingot according to an embodiment of the present invention.

[0023] Figure 2 FIG. 1 is a schematic diagram of a partial structure of a multi-wire saw according to an embodiment of the present invention.

[0024] Figure 3 This is a schematic structural diagram of a guide wheel wound with multiple cutting wires according to an embodiment of the present invention.

[0025] Figure 4FIG. 1 is a schematic diagram of the layout of nozzles of a multi-wire saw according to an embodiment of the present invention. DETAILED DESCRIPTION

[0026] To make the purpose, technical solutions and advantages of the embodiments of the present invention more clear, the embodiments of the present invention are further described in detail below with reference to the accompanying drawings. Here, the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0027] It should be noted here that, in order to avoid obscuring the present invention due to unnecessary details, the accompanying drawings only show structures and / or processing steps closely related to the solutions according to the present invention, while other details that are not closely related to the present invention are omitted.

[0028] It should be emphasized that the terms “include / comprises / has” when used herein refer to the existence of features, elements, steps or components, but do not exclude the existence or addition of one or more other features, elements, steps or components.

[0029] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the accompanying drawings, the same reference numerals represent the same or similar components, or the same or similar steps.

[0030] Figure 1 FIG. 1 is a flow chart of a cutting method of a multi-wire saw for a sapphire crystal rod according to an embodiment of the present invention. Figure 1 As shown, the cutting method of the multi-wire saw for sapphire crystal ingot includes at least steps S10 to S20.

[0031] Step S10: Fixing the sapphire crystal ingot on the crystal ingot fixing device of the multi-wire sawing machine, and making the end face of the sapphire crystal ingot to be cut parallel to the cutting direction of the cutting wire.

[0032] In this step, the cutting line refers to the multiple cutting lines on the multi-wire cutting machine used to wind around the guide wheel. When the multiple cutting lines cut the sapphire crystal rod into multiple sapphire wafers, the cutting direction of the cutting line can be regarded as the end face direction of the wafer, that is, the separation surface of any two adjacent sapphire wafers cut from the sapphire crystal rod can be regarded as the end face to be cut. Therefore, when the sapphire crystal rod is actually cut, the sapphire crystal rod generally moves toward the multiple cutting lines or the multiple cutting lines move toward the sapphire crystal rod. At this time, when the axis of the sapphire crystal rod is set horizontally, the cutting direction of the cutting line can be regarded as the vertical direction perpendicular to the horizontal direction.

[0033] Exemplarily, the crystal rod fixing device can be a swinging workbench, which can be specifically located directly above the cutting line. In this case, the sapphire crystal rod is placed on the swinging workbench as a workpiece, and the swinging workbench itself can swing so that the workpiece on the swinging workbench can better cooperate with the multiple cutting lines. The swinging workbench can further achieve lifting motion through a lifting mechanism. Under the lifting and swinging motions of the swinging workbench, the sapphire crystal rod cooperates with the multiple cutting lines to achieve cutting. The lifting mechanism can exemplarily include a lifting drive component and a lifting transmission mechanism. In this case, the lifting drive component is connected to the swinging workbench through the lifting transmission mechanism. The lifting transmission mechanism is a mechanism that can convert the rotational output of the lifting drive component into reciprocating linear motion, such as a screw-nut mechanism, a gear rack mechanism, etc. When the lifting transmission mechanism is a screw-nut mechanism, the screw can be connected to the output shaft of the lifting drive component, and the screw and the output shaft of the lifting drive component rotate synchronously. The nut is further fixedly connected to the swing worktable. When the screw rotates with the output shaft of the lifting drive component, the nut moves along the axial direction of the screw. The screw is specifically arranged vertically. Since the swing worktable is fixedly connected to the nut, the swing worktable achieves lifting motion under the drive of the lifting drive component. It should be understood that the specific structure and layout of the lifting mechanism and the swing worktable can be set according to the actual application scenario.

[0034] Step S20: The sapphire crystal ingot is moved vertically toward the cutting wires, a guide wheel wrapped with multiple cutting wires is rotated, and a cooling medium is sprayed onto the surface of the sapphire crystal ingot through a cooling device. The components of the cooling medium include water-based cutting fluid and alkaline compounds. The rotation of the guide wheel causes the cutting wires to reciprocate to cut the sapphire crystal ingot; wherein the flow rate of the alkaline compound sprayed per unit volume at the first end of the sapphire crystal ingot is greater than the flow rate of the alkaline compound sprayed per unit volume at the second end of the sapphire crystal ingot, the first end of the sapphire crystal ingot is cut by the multiple cutting wires close to the wire entry end, and the second end of the sapphire crystal ingot is cut by the multiple cutting wires close to the wire exit end.

[0035] In this step, if you want to achieve linear movement of the sapphire crystal rod, you can drive the swing workbench to move up and down through the lifting mechanism. Figure 2 A partial structural diagram of a multi-wire cutting machine according to an embodiment of the present invention is shown in FIG. Figure 2Multiple cutting wires are wound around two guide wheels (left and right), which are parallel and spaced apart. The multiple cutting wires located between the two guide wheels cut the sapphire ingot, so the sapphire ingot is positioned directly above the multiple cutting wires between the two guide wheels. When cutting the sapphire ingot, the guide wheels with the multiple cutting wires rotate. This rotation causes the wire network composed of the multiple cutting wires to move back and forth on the guide wheels. When the reciprocating cutting wires contact the sapphire ingot, they cut the sapphire ingot.

[0036] As a high-precision cutting device for brittle and hard materials, the multi-wire saw is affected by many factors, including the machining accuracy of the mechanical components, electrical stability, and temperature. During the sapphire crystal rod cutting process, the grinding between the cutting wire and the workpiece generates a large amount of heat. If the heat is not removed in time, the sapphire crystal rod will deform due to thermal expansion and contraction. This deformation will reduce the cutting accuracy. Therefore, to alleviate this phenomenon, the sapphire crystal rod is cooled by a cooling device during the cutting process. In the prior art, the cooling method used for sapphire crystal rods is generally to spray water-based cutting fluid onto the sapphire crystal rod. The flowing water-based cutting fluid will remove a large amount of heat from the sapphire crystal rod, cooling the sapphire crystal rod during the cutting process.

[0037] In this step, the cooling medium sprayed onto the sapphire crystal rod in the present application comprises a water-based cutting fluid and an alkaline compound. The flow of the water-based cutting fluid can remove heat from the crystal rod, while the alkaline compound will soften the sapphire crystal rod to a certain extent, thereby facilitating the cutting of the sapphire crystal rod by the cutting wire. Furthermore, by controlling the amount of alkaline compound sprayed at different locations on the sapphire crystal rod, the degree of softening at different locations on the sapphire crystal rod varies. In this embodiment, the amount of alkaline compound sprayed at the first end of the sapphire crystal rod is greater than the amount of alkaline compound sprayed at the second end. In this case, the degree of softening at the first end is higher than that at the second end. The first end of the sapphire crystal rod refers to the portion cut by the cutting wire on the incoming wire side when it is cut, while the second end refers to the portion cut by the cutting wire on the outgoing wire side. In this embodiment, the sapphire crystal ingot is softened as a whole. Sapphire wafers cut from the softened crystal ingot have a correspondingly reduced warpage relative to sapphire wafers cut from the unsoftened crystal ingot. Furthermore, the softened sapphire crystal ingot has a higher cutting efficiency without increasing the cutting capacity of the cutting wire. Furthermore, the softening degree of the portion of the sapphire crystal ingot near the wire entry end is higher than that of the portion near the wire exit end. This compensates for the warpage difference between the wafers at the wire entry end and the wire exit end, which is caused by the stronger cutting capacity of the wire entry end. Consequently, after the softened sapphire crystal ingot is cut by multiple cutting wires wound around a guide wheel, the warpage difference between the wafers at the wire entry end and the wire exit end is greatly reduced, ensuring that the morphology of the wafers cut from both ends of the crystal ingot remains consistent, thereby improving the yield rate during the wafer processing process.

[0038] In one embodiment of the present invention, the cooling medium is formed by mixing the water-based cutting fluid and the alkaline compound. In this case, the cooling medium only contains the water-based cutting fluid and the alkaline compound. Limiting the cooling medium to a mixture of the water-based cutting fluid and the alkaline compound not only achieves a good softening effect, but also maintains a good cooling rate. It is understandable that the cooling medium being a mixture of the water-based cutting fluid and the alkaline compound is only a preferred example. In its application scenario, the cooling medium may also contain other substances in addition to the water-based cutting fluid and the alkaline compound.

[0039] Furthermore, the alkaline compound is potassium hydroxide or sodium hydroxide. Both potassium hydroxide and sodium hydroxide are strong bases that form an alkaline solution when dissolved in a water-based cutting fluid. In this embodiment, using a strong base as the alkaline compound can achieve a better softening effect on the sapphire crystal rod, thereby further reducing the difference in warpage between the wafer at the input and output ends. It should be understood that in addition to strong bases such as potassium hydroxide and sodium hydroxide, weak bases can also be used as the alkaline compound.

[0040] Specifically, when the cooling medium is a mixture of a water-based cutting fluid and an alkaline compound, and the alkaline compound is potassium hydroxide, the volume ratio of the water-based cutting fluid to the potassium hydroxide in the cooling medium ranges from 10:1 to 20:1. A cooling medium with a volume ratio of the water-based cutting fluid to the potassium hydroxide within the above range can effectively remove heat from the sapphire crystal ingot while softening it. Alternatively, the volume ratio of the water-based cutting fluid to the potassium hydroxide in the cooling medium is 20:1, and the cooling medium contains 5% KOH (potassium hydroxide). When the sapphire crystal ingot is cut using a multi-wire saw and the cooling medium containing 5% KOH is sprayed onto the surface of the sapphire crystal ingot, the entire sapphire crystal ingot is softened. The warpage of the wafer located on the wire entry side of the cut wafer is reduced to 20 to 25 μm, while the warpage of the wafer located on the wire entry side obtained by the conventional cutting method of spraying only the water-based cutting fluid onto the surface of the sapphire crystal ingot reaches 40 to 50 μm. As shown above, the warpage of wafers obtained by spraying a cooling medium containing 5% KOH onto the surface of the sapphire ingot during slicing is significantly lower than that of wafers obtained by simply spraying a water-based cutting fluid onto the surface of the sapphire ingot. Furthermore, this method not only reduces the warpage of wafers on the entry side to 20 to 25 μm, but also improves surface conformity by 20%.

[0041] The proportion of potassium hydroxide in the cooling medium affects the quality of the wafers obtained by cutting. If the potassium hydroxide content in the cooling medium is too low, the sapphire crystal rod will not achieve a good softening effect; if the potassium hydroxide content in the cooling medium is too high, it will affect the cooling rate of the sapphire crystal rod. Therefore, in this application, it is important to find a cooling medium with an appropriate potassium hydroxide ratio. Preferably, the volume ratio of water-based cutting fluid to potassium hydroxide in the cooling medium is 20:1. Alternatively, the volume ratio of water-based cutting fluid to potassium hydroxide in the cooling medium can be 10:1, that is, the cooling medium contains 10% KOH. Based on this cooling medium, after cutting sapphire crystal rods using the cutting method of the multi-wire saw of the present invention, it was found that the warpage of the cut sapphire wafer at the wire entry end can be reduced to 30μm to 35μm. Although this method reduces the warpage of the sapphire wafer at the wire entry end from 40 to 50μm to 30μm to 35μm, the technical effect it brings is far inferior to the technical effect achieved by using a cooling medium containing 5% KOH.

[0042] In addition to the above, the cooling medium can also be a mixture of water-based cutting fluid and sodium hydroxide, which is also a strong alkaline compound. For example, the volume ratio of water-based cutting fluid to sodium hydroxide in the cooling medium can also be 20:1. In this case, the cooling medium contains 5% NaOH. After cutting a sapphire crystal rod using the cutting method of the multi-wire sawing machine of the present invention based on this cooling medium, it was found that the warpage of the sapphire wafer located at the wire end after cutting was 30μm to 35μm. Similarly, although it improved the warpage of the sapphire wafer at the wire end to a certain extent, its effect was not ideal compared to the multi-wire sawing method using a cooling medium containing 5% KOH. In addition, in this application, the purpose of mixing the cooling medium with a water-based cutting fluid and an alkaline compound is to soften the crystal rod while ensuring that the crystal rod can achieve a higher cooling rate. Therefore, for the cooling medium composed of a mixture of water-based cutting fluid and sodium hydroxide, although the increase in the sodium hydroxide content increases the softening degree of the crystal rod, its cooling effect is greatly reduced, thereby also affecting the manufacturing accuracy of the wafer.

[0043] In one embodiment, the ratio of the alkaline compound flow rate per unit volume sprayed at the first end of the sapphire crystal ingot to the alkaline compound flow rate per unit volume sprayed at the second end of the sapphire crystal ingot ranges from 4:1 to 3:2. In this embodiment, the alkaline compound flow rate per unit volume sprayed at the inlet end of the sapphire crystal ingot is 1.5 to 4 times the alkaline compound flow rate per unit volume sprayed at the outlet end of the sapphire crystal ingot, and the corresponding softening degree of the inlet end of the crystal ingot is 1.5 to 4 times the softening degree of the outlet end. Preferably, the alkaline compound flow rate per unit volume sprayed at the inlet end of the sapphire crystal ingot is twice the alkaline compound flow rate per unit volume sprayed at the outlet end of the sapphire crystal ingot, and the softening degree of the inlet end of the crystal ingot is twice the softening degree of the outlet end of the crystal ingot. Under this limitation, the warpage of the sapphire wafer corresponding to the inlet end can be reduced to 20 μm to 25 μm.

[0044] In the above embodiment, the softening degree of the sapphire crystal rod at the inlet end is higher than that at the outlet end. However, the softening degree of the portion of the crystal rod located between the inlet and outlet ends may also be located between the inlet and outlet ends. For example, the flow rate of the alkaline compound injected per unit volume of the sapphire crystal rod gradually decreases from the first end to the second end. In this case, the softening degree of the sapphire crystal rod gradually decreases from the inlet end to the outlet end, that is, the softening degree is highest at the inlet end and lowest at the outlet end. At this time, the sapphire crystal rod gradually softens as the cutting power of the cutting wire changes, which correspondingly compensates for the difference in warping of each wafer when different parts of the crystal rod are cut, thereby maintaining the consistent morphology of the wafers corresponding to different parts of the sapphire crystal rod, thereby improving the wafer processing yield.

[0045] Accordingly, the present invention also provides a multi-wire saw for sapphire crystal rods, which uses the cutting method of the multi-wire saw for sapphire crystal rods described in any of the above embodiments when cutting sapphire crystal rods. Figure 2 The multi-wire cutting machine at least includes a wire supply spool, a wire take-up spool, a swing workbench, two guide wheels, a cooling device, a wire net and a plurality of tension wheels; the wire net is wound on the guide wheel as a cutting wire. Figure 2 When the two guide wheels rotate counterclockwise, the cutting wire wound on the supply spool is gradually taken up by the take-up spool. If the two guide wheels rotate clockwise, the cutting wire wound on the take-up spool is gradually taken up by the supply spool. Thus, the cutting wire wound on the guide wheels realizes reciprocating motion, i.e., the cutting wire reciprocating wire saw cuts the sapphire crystal rod. The wire entry end is the guide wheel, the front end of the sapphire crystal rod ( Figure 2 The outlet end is the guide wheel and the rear end of the sapphire crystal rod. Figure 3 FIG. 1 is a structural diagram of a guide wheel of a multi-wire sawing machine according to an embodiment of the present invention. Figure 3 As shown, the cutting wire is wound around the left and right guide wheels with a certain groove pitch on the surface to form a wire mesh. The cutting wire located at the top of the guide wheel serves as the upper wire mesh, while the cutting wire located at the bottom of the guide wheel serves as the lower wire mesh. The cutting wires of the upper wire mesh are parallel to the end face of the guide wheel, while the cutting wires of the lower wire mesh are inclined to the end face of the guide wheel. When the sapphire crystal rod is cut, the upper wire mesh participates in the cutting of the sapphire crystal rod.

[0046] Furthermore, the cooling device includes multiple nozzles spaced apart along the length of the ingot. A cooling medium comprising a water-based cutting fluid and an alkaline compound is sprayed from the multiple nozzles onto the surface of the sapphire ingot, thereby softening the ingot. To ensure that the flow rate of the alkaline compound sprayed per unit volume at the first end of the sapphire ingot is greater than the flow rate of the alkaline compound sprayed per unit volume at the second end of the sapphire ingot, the spacing between any two adjacent nozzles near the second end of the sapphire ingot is 1.5 to 4 times the spacing between any two adjacent nozzles near the first end of the sapphire ingot. In other words, the nozzles at the outlet end are more sparsely spaced than those at the inlet end. As will be appreciated, the more sparse the nozzles, the less alkaline compound flow rate per unit volume of the sapphire ingot is received, and the corresponding portion of the sapphire ingot is softened less. Figure 4This is a schematic diagram of the nozzle layout of one embodiment of the invention, wherein the left end of the nozzle tube 111 corresponds to the inlet end, and the right end of the nozzle tube 111 corresponds to the outlet end. The nozzle tube 111 has multiple nozzles 112, and there is a spacing between any two nozzles 112. The spacing between the nozzles 112 on the inlet side of the nozzle tube 111 is 30 mm, while the spacing between the nozzles 112 on the outlet side is 60 mm. In this case, the spacing between the nozzles 112 on the outlet side is twice the spacing between the nozzles 112 on the inlet side. In addition to the above, the spacing between adjacent nozzles 112 on the nozzle tube 111 can also gradually increase from the first end to the second end of the sapphire crystal rod; for example, the spacing between the nozzles 112 on the nozzle tube 111 gradually increases from 30 mm to 60 mm from the inlet end to the outlet end. It should be understood that the length of the nozzle tube 111 and the spacing between the nozzles 112 listed above can be replaced according to the actual application scenario, as long as the flow rate of the cooling medium at the input end is greater than the flow rate of the cooling medium at the output end, so as to better soften the crystal rod at the input end and accelerate the heat dissipation of the crystal rod at the input end.

[0047] Through the above embodiments, it can be found that the cutting method and the multi-wire sawing machine for sapphire crystal rod disclosed in the present invention add 5% KOH to the cooling medium to make KOH react with the crystal rod ((Al2O3+2OH - =2AlO2 - +H2O)) to soften the crystal rod, which is beneficial for multi-wire cutting of the sapphire crystal rod; in addition, the flow rate of the alkaline compound sprayed per unit volume at the first end of the sapphire crystal rod is greater than the flow rate of the alkaline compound sprayed per unit volume at the second end of the sapphire crystal rod, so that the softening degree of the sapphire crystal rod at the inlet end is higher than that at the outlet end, thereby reducing the warpage of the wafer cut at the inlet end, thereby reducing the difference in warpage of each wafer caused by the inconsistent cutting capacity of the inlet and outlet ends, and ensuring that the morphology of each wafer remains basically consistent.

[0048] Those skilled in the art will appreciate that the various exemplary components, systems, and methods described in conjunction with the embodiments disclosed herein can be implemented in hardware, software, or a combination of both. Whether hardware or software is used depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of the present invention. When implemented in hardware, it may be, for example, an electronic circuit, an application-specific integrated circuit (ASIC), appropriate firmware, a plug-in, a function card, etc. When implemented in software, the elements of the present invention are programs or code segments used to perform the required tasks. The program or code segment may be stored in a machine-readable medium or transmitted over a transmission medium or communication link via a data signal carried in a carrier wave. "Machine-readable medium" may include any medium capable of storing or transmitting information. Examples of machine-readable media include electronic circuits, semiconductor memory devices, ROM, flash memory, erasable ROM (EROM), floppy disks, CD-ROMs, optical disks, hard disks, fiber optic media, radio frequency (RF) links, etc. The code segments may be downloaded via a computer network such as the Internet or an intranet.

[0049] It should also be noted that the exemplary embodiments described herein describe methods or systems based on a series of steps or devices. However, the present invention is not limited to the order of the steps described above. In other words, the steps may be performed in the order described in the embodiments, or in a different order, or several steps may be performed simultaneously.

[0050] In the present invention, features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, and / or combined with or replace features of other embodiments.

[0051] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A cutting method for a multi-wire saw for a sapphire crystal rod, characterized in that: The cutting method comprises: Fixing the sapphire crystal ingot on the crystal ingot fixing device of the multi-wire sawing machine, and making the end face of the sapphire crystal ingot to be cut parallel to the cutting direction of the cutting wire; The sapphire ingot is moved vertically toward the cutting wires, a guide wheel wrapped with multiple cutting wires is rotated, and a cooling medium is sprayed onto the surface of the sapphire ingot via a cooling device. The cooling medium comprises a water-based cutting fluid and an alkaline compound. The rotation of the guide wheel causes the cutting wires to reciprocate to cut the sapphire ingot. The flow rate of the alkaline compound sprayed per unit volume at the first end of the sapphire ingot is greater than the flow rate of the alkaline compound sprayed per unit volume at the second end of the sapphire ingot. The first end of the sapphire ingot is cut by the multiple cutting wires near the wire entry end, and the second end of the sapphire ingot is cut by the multiple cutting wires near the wire exit end. The cooling medium is a mixture of the water-based cutting fluid and the alkaline compound. Among them, the cutting line located at the top of the guide wheel serves as the upper wire mesh, and the cutting line located at the bottom of the guide wheel serves as the lower wire mesh. The cutting lines of the upper wire mesh are parallel to the end face of the guide wheel, while the cutting lines of the lower wire mesh are inclined to the end face of the guide wheel.

2. The cutting method of the multi-wire saw for sapphire crystal ingot according to claim 1, characterized in that: The alkaline compound is potassium hydroxide or sodium hydroxide.

3. The cutting method of the multi-wire saw for sapphire crystal ingot according to claim 2, characterized in that: When the alkaline compound is potassium hydroxide, the volume ratio of the water-based cutting fluid to potassium hydroxide in the cooling medium is in a range of 10:1 to 20:

1.

4. The cutting method of the multi-wire saw for sapphire crystal ingot according to claim 3, characterized in that: The volume ratio of the water-based cutting fluid to potassium hydroxide in the cooling medium is 20:

1.

5. The cutting method of the multi-wire saw for sapphire crystal ingot according to claim 1, characterized in that: The ratio of the flow rate of the alkaline compound sprayed per unit volume at the first end of the sapphire crystal rod to the flow rate of the alkaline compound sprayed per unit volume at the second end of the sapphire crystal rod ranges from 4:1 to 3:

2.

6. The cutting method of the multi-wire saw for sapphire crystal ingot according to claim 1, characterized in that: The flow rate of the alkaline compound sprayed per unit volume of the sapphire crystal rod gradually decreases from the first end to the second end.

7. A multi-wire saw for sapphire crystal rods, characterized in that: The multi-wire sawing machine adopts the cutting method for a multi-wire sawing machine for a sapphire crystal ingot according to any one of claims 1 to 6 when cutting the sapphire crystal ingot.

8. The multi-wire saw for sapphire crystal ingot according to claim 7, characterized in that: The cooling device includes a plurality of nozzles arranged at intervals along the length direction of the crystal rod.

9. The multi-wire saw for sapphire ingot according to claim 8, characterized in that: The distance between any two adjacent nozzles near the second end of the sapphire crystal rod is 1.5 to 4 times the distance between any two adjacent nozzles near the first end of the sapphire crystal rod.

10. The multi-wire saw for sapphire ingot according to claim 8, characterized in that: The distance between two adjacent nozzles gradually increases from the first end to the second end of the sapphire crystal rod.

Images