Liquid phase method silicon carbide single crystal slicing method and device

Abstract

The invention relates to the technical field of crystal slicing processing, and discloses a liquid phase method silicon carbide single crystal slicing method and device, and the method comprises the following steps: S1, determining the wafer cutting thickness H, and selecting the parameters of a diamond wire; s2, working parameters of the diamond wire are determined according to the wafer cutting thickness H and parameters of the diamond wire; and S3, carrying out single-piece slicing on the crystal in a surrounding type layer-by-layer progressive manner. According to the invention, the single crystal is sliced in a surrounding layer-by-layer progressive manner, so that the slicing yield is greatly improved, and meanwhile, the cutting speed can be improved by a one-time method, and the processing efficiency is improved; the tension controller and the wire diameter detector are matched with the PLC system to regulate and control the state of the diamond wire, so that the consistency of tension density is ensured, and finally higher cutting quality is ensured; meanwhile, the problems that the diamond wire is high in breakage rate, large in wire loss, weak in abrasion resistance and the like are solved.

Description

Technical Field

[0001] This invention relates to the field of crystal slicing technology, specifically to a liquid-phase silicon carbide single crystal slicing method and apparatus. Background Technology

[0002] Silicon carbide (SiC), as a core representative of third-generation semiconductor materials, has shown irreplaceable application value in fields such as power electronics, radio frequency devices, optoelectronics and high-temperature sensing due to its wide bandgap, high breakdown field strength, high thermal conductivity and excellent chemical stability.

[0003] Of all the processing steps from silicon carbide single crystal to substrate wafer, the slicing step is particularly important. Currently, the industry typically uses electroplated diamond wire to cut silicon carbide single crystals. For example... Figure 1 The diagram shows a simplified representation of existing technology. During the cutting process, the diamond wire maintains a constant feed rate, while the silicon carbide single crystal maintains a constant rotation speed for cutting. This technology was developed by the industry for silicon carbide single crystals prepared by the PVT method. Currently, the processing technology for silicon carbide single crystals prepared by the liquid phase method also references related technologies from the PVT method. However, there are significant differences in the physical properties and machinability of silicon carbide single crystals prepared by the two technologies. Therefore, the industry currently faces a series of problems that urgently need to be addressed: firstly, the slicing yield is low, with defects such as microcracks and even macrocracks in the wafers; secondly, there are problems such as high diamond wire breakage rate, large wire loss, and weak wear resistance; and thirdly, there are problems such as low cutting speed. To further promote the development of the industry, it is essential to develop a new slicing processing technology and device. Summary of the Invention

[0004] The purpose of this invention is to provide a liquid-phase silicon carbide single crystal slicing method and apparatus, which solves the problems of low slicing yield, microcracks or even macrocracks in the wafers, high diamond wire breakage rate, large wire loss and weak wear resistance in existing methods.

[0005] This invention is achieved through the following technical solution: a liquid-phase silicon carbide single crystal slicing method, comprising the following steps: Step S1: Determine the wafer cutting thickness H and select the parameters of the diamond wire itself; Step S2: Determine the working parameters of the diamond wire based on the wafer cutting thickness H and the parameters of the diamond wire itself; Step S3: Slice the crystal into single slices using a progressive, layer-by-layer method. Step S4: After the single wafer is sliced, the diamond wire moves along the crystal axis to cut the next wafer.

[0006] To better realize the present invention, in step S1, the diamond wire is tungsten wire diamond wire or carbon steel diamond wire, and its wire diameter is D. rThe real-time wire diameter has a cross-sectional area of... .

[0007] To better realize the present invention, further, in step S2, the initial distance between the diamond wire and the crystal is set to h0, and the crystal position at this time is taken as the initial position, denoted as the initial position L0; the feed amount S of the diamond wire per pass is set. f Precession velocity V f Feed displacement S and linear velocity V t The radius R of the crystal.

[0008] To better realize the present invention, the specific steps of the slicing in step S3, which involves a progressive layer-by-layer approach, are as follows: Step S31: A rotation period of 360° is considered as one rotation cycle, and the total number of cycles N is R / S. f and round up; Step S32: Using the initial position of the crystal as the reference sub-step, each 60° rotation of the reference sub-step is a new sub-step, and returning to the initial position after a 360° rotation is one cutting cycle C; Step S33: Use diamond wire to slice the crystal. Each time a cutting cycle is completed, the crystal will be cut deeper until the crystal is completely cut through to obtain a wafer.

[0009] To better realize the present invention, further, in step S33, the specific steps of slicing are as follows: Step S331: Start a cutting cycle C, with an initial value of 1 for C; Step S332: Using the reference sub-step as the first sub-step, when the diamond wire reaches the feed displacement S, the diamond wire moves S in the opposite direction of the feed. b The crystal rotates 60°. Step S333: After the crystal rotation is complete, the second sub-step begins. When the diamond wire reaches the feed displacement S, the diamond wire moves S in the opposite direction of the feed. b The crystal rotates 60°. Step S334: Repeat step S333 until the sixth sub-step is completed. When the diamond wire reaches the feed displacement S, the diamond wire moves S in the opposite direction of the feed. b The crystal rotates 60°, at which point the first cutting cycle ends, completing one circumferential cutting; Step S335: Repeat steps S331-S334 to complete the second, third...Nth cutting cycle, realizing progressive cutting until the wafer is cut from the crystal.

[0010] To better realize the present invention, the value of the feed displacement S is further determined according to the following criteria: when hour, ;in ; when and hour, ;in ; when and hour, .

[0011] To better realize the present invention, further, the reverse displacement S b The value of S is: when executing the first to the fifth substeps. b =S, when executing the sixth substep, S b The values ​​are determined based on the following: when hour, ;in ; when and hour, ;in ; when and hour, .

[0012] To better realize the present invention, further, in step S4, the diamond wire moves a distance S along the crystal axis. L =D r +k+H, where 10μm≤k≤150μm.

[0013] To better realize the present invention, tension density is further introduced during the slicing process. To measure the cutting state of the diamond wire. .

[0014] A liquid-phase silicon carbide single crystal slicing apparatus, comprising: Diamond wire, used for cutting crystals; Tension controller, used to control the running tension of diamond wire; Wire diameter detector, used to detect the real-time wire diameter of diamond wire; The cutting system is used to drive the diamond wire to perform the cutting action; The PLC system, connected to the tension controller, wire diameter detector, and cutting system, is used to collect data and regulate the operating status of the diamond wire.

[0015] Compared with the prior art, the present invention has the following advantages and beneficial effects: (1) The present invention uses a layer-by-layer method to slice crystals one slice at a time, which greatly improves the slicing yield. At the same time, the one-time method can improve the cutting speed and improve the processing efficiency. (2) This invention uses a tension controller, a wire diameter detector and a PLC system to regulate the state of diamond wire to ensure consistent tension density and ultimately ensure high cutting quality; at the same time, it improves the problems of high diamond wire breakage rate, large wire loss and weak wear resistance. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a partial structure of the slicing device.

[0017] Figure 2 This is a schematic diagram of the slicing device.

[0018] Figure 3 This is a schematic diagram of the diamond wire feed direction.

[0019] Figure 4 Schematic diagram of crystal slice state Figure 1 .

[0020] Figure 5 Schematic diagram of crystal slice state Figure 2 .

[0021] Figure 6 This is a schematic diagram of the control principle of a PLC system.

[0022] Among them: 10-PLC system; 201-diamond wire; 202-tension controller; 203-wire diameter detector; 204-cutting system; 30-crystal. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] Example 1: This embodiment provides a liquid-phase silicon carbide single-crystal slicing method, specifically as follows: Figures 1-5 As shown, it includes the following steps: Step S1: Determine the wafer cutting thickness H and select the parameters of the diamond wire 201. Step S2: Determine the working parameters of the diamond wire 201 based on the wafer cutting thickness H and the parameters of the diamond wire 201 itself; Step S3: Slice the crystal 30 into single slices using a progressive, layer-by-layer method. Step S4: After the single wafer is sliced, the diamond wire 201 moves along the crystal 30 axis to cut the next wafer.

[0026] Example 2: This embodiment further extends the above embodiment. In step S1, the diamond wire 201 is either tungsten wire diamond wire or carbon steel diamond wire. In this embodiment, tungsten wire diamond wire is preferred, and its initial wire diameter is D. r The real-time wire diameter has a cross-sectional area of... .

[0027] In step S2, the initial distance between the diamond wire 201 and the crystal 30 is set to h0, and the current position of the crystal 30 is taken as the initial position, denoted as initial position L0; the diamond wire feed direction is made parallel to a specific crystal orientation of the crystal, such as... Figure 3 shown , Wait, set the feed rate S of diamond wire 201 per pass. f (0 < S) f ≤5mm), advance speed V f (0 < V) f ≤0.5mm / min), feed displacement S and linear velocity V t (10m / s < V) t (≤30m / s), the radius R of the crystal.

[0028] The value of the feed displacement S is determined based on: when hour, ;in ; when and hour, ;in ; when and hour, .

[0029] The specific steps of the layer-by-layer slicing in step S3 are as follows: Step S31: Rotate crystal 30 by 360° as one rotation cycle (rotation speed 0 < V) r ≤100rpm), total number of cycles N is R / S f and round up; Step S32: Taking the initial position of crystal 30 as the reference sub-step, each 60° rotation of the reference sub-step is a new sub-step, and returning to the initial position after a 360° rotation is a cutting cycle C; Since the cutting is performed on a hexagonal silicon carbide crystal, it can be known from the hexagonal silicon carbide crystal structure that each 60° rotation is equivalent to the hexagonal crystal structure. Step S33: Use diamond wire 201 to slice crystal 30. After each slicing cycle, crystal 30 will be sliced ​​deeper until crystal 30 is completely cut through to obtain wafer.

[0030] In step S33, the specific steps for slicing are as follows: Step S331: Start a cutting cycle C, with an initial value of 1 for C; Step S332: Using the reference sub-step as the first sub-step, when the diamond wire 201 reaches the feed displacement S, the diamond wire 201 moves S in the opposite direction of the feed. b The displacement is S b =S, Movement speed 0 < V b ≤10m / s, then the crystal rotates 30° by 60°; After step S333, when the crystal 30 has finished rotating, the second sub-step begins. When the diamond wire 201 reaches the feed displacement S, the diamond wire 201 moves S in the opposite direction of the feed. b The displacement is S b =S, Movement speed 0 < V b ≤10m / s, then the crystal rotates 30° by 60°; Step S334: Repeat step S333 until the sixth sub-step is completed. When the diamond wire 201 reaches the feed displacement S, the diamond wire 201 moves S in the opposite direction of the feed. b The crystal rotates 60°, at which point the first cutting cycle ends, completing one circumferential cutting; when the sixth sub-step is completed, S... b A specific judgment is needed, based on the following: when hour, ;in ; when and hour, ;in ; when and hour, .

[0031] Step S335: Repeat steps S331-S334 to complete the second (C=2), third (C=3)...Nth (C=N) cutting cycle, realizing layer-by-layer progressive cutting until the wafer is cut away from the crystal 30.

[0032] In step S4, the diamond wire 201 moves a distance S along the axial direction of the crystal 30. L =D r +k+H, where 10μm≤k≤150μm.

[0033] The other parts of this embodiment are the same as those in the above embodiments, and will not be described again.

[0034] Example 3: This embodiment further extends the above embodiment by introducing tension density during the slicing process. To measure the cutting state of diamond wire 201, .

[0035] like Figure 6 As shown, real-time data is obtained through the tension controller 202 and the wire diameter detector 203. The value will be real-time. Values ​​and presets The values ​​are compared, and then the diameter of the diamond wire 201 is further determined to cooperate with the PLC system 10 to adjust the tension density based on tension data and wire diameter data. The process involves adjusting the relevant parameters of the cutting system 204 to ensure consistent tension density and ultimately guarantee high cutting quality.

[0036] The other parts of this embodiment are the same as those in the above embodiments, and will not be described again.

[0037] Example 4: This embodiment provides a liquid-phase silicon carbide single crystal slicing apparatus, specifically as follows: Figure 1 , Figure 2 As shown, it includes: Diamond wire 201, used for cutting crystal 30; Tension controller 202 is used to control the running tension of diamond wire 201; The wire diameter detector 203 can be a laser scanning diameter meter or a CCD projection diameter meter, used to detect the real-time wire diameter of the diamond wire 201; The cutting system 204 is used to drive the diamond wire 201 to perform cutting operations; it includes driving the diamond wire 201 to rotate and feed. The PLC system 10 is connected to the tension controller 202, wire diameter detector 203, and cutting system 204, and is used to collect data and regulate the operating status of the diamond wire 201.

[0038] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A liquid-phase method for slicing silicon carbide single crystals, characterized in that, Includes the following steps: Step S1: Determine the wafer cutting thickness H and select the parameters of the diamond wire (201); Step S2: Determine the working parameters of the diamond wire (201) based on the wafer cutting thickness H and the parameters of the diamond wire (201). Step S3: Slice the crystal (30) into single slices using a layer-by-layer approach. Step S4: After the single wafer is sliced, the diamond wire (201) moves along the crystal (30) axis to cut the next wafer.

2. The liquid-phase silicon carbide single-crystal slicing method according to claim 1, characterized in that: In step S1, the diamond wire (201) is either tungsten wire diamond wire or carbon steel diamond wire, and its diameter is D. r The real-time wire diameter has a cross-sectional area of... .

3. The liquid-phase silicon carbide single-crystal slicing method according to claim 2, characterized in that, In step S2, the initial distance between the diamond wire (201) and the crystal (30) is set to h0, and the position of the crystal (30) at this time is taken as the initial position, denoted as the initial position L0; the feed amount S of the diamond wire (201) is set for each step. f Precession velocity V f Feed displacement S and linear velocity V t The radius R of the crystal.

4. The liquid-phase silicon carbide single-crystal slicing method according to claim 3, characterized in that, The specific steps of the layer-by-layer slicing in step S3 are as follows: Step S31: Rotate the crystal (30) 360° as one rotation cycle, and the total number of cycles N is R / S f and round up; Step S32: Take the initial position of the crystal (30) as the reference sub-step, rotate the reference sub-step by 60° for each new sub-step, and return to the initial position after rotating 360° for one cutting cycle C; Step S33: Use diamond wire (201) to slice the crystal (30). After each cutting cycle, the crystal (30) will be cut deeper until the crystal (30) is completely cut through to obtain a wafer.

5. The liquid-phase silicon carbide single-crystal slicing method according to claim 4, characterized in that, In step S33, the specific steps for slicing are as follows: Step S331: Start a cutting cycle C, with an initial value of 1 for C; Step S332: Using the reference sub-step as the first sub-step, when the diamond wire (201) reaches the feed displacement S, the diamond wire (201) moves S in the opposite direction of the feed. b The crystal (30) is rotated 60°; Step S333: After the crystal (30) has rotated, the second sub-step begins. When the diamond wire (201) reaches the feed displacement S, the diamond wire (201) moves S in the opposite direction of the feed. b The crystal (30) is rotated 60°; Step S334: Repeat step S333 until the sixth sub-step is completed. When the diamond wire (201) reaches the feed displacement S, the diamond wire (201) moves S in the opposite direction of the feed. b The crystal (30) rotates 60°, at which point the first cutting cycle ends, completing one circumferential cutting; Step S335: Repeat steps S331-S334 to complete the second, third...Nth cutting cycle, realizing progressive cutting until the wafer is cut away from the crystal (30).

6. The liquid-phase silicon carbide single-crystal slicing method according to claim 5, characterized in that, The value of the feed displacement S is determined based on the following: when hour, ;in ; when and hour, ;in ; when and hour, .

7. The liquid-phase silicon carbide single-crystal slicing method according to claim 5, characterized in that, The opposite displacement S b The value of S is: when executing the first to the fifth substeps. b =S, when executing the sixth substep, S b The values ​​are determined based on the following: when hour, ;in ; when and hour, ;in ; when and hour, .

8. The liquid-phase silicon carbide single-crystal slicing method according to claim 2, characterized in that, In step S4, the diamond wire (201) moves a distance S along the axial direction of the crystal (30). L =D r +k+H, where 10μm≤k≤150μm.

9. The liquid-phase silicon carbide single-crystal slicing method according to claim 2, characterized in that, Introducing tension density during slicing To measure the cutting state of the diamond wire (201), .

10. A liquid-phase silicon carbide single crystal slicing apparatus, used to perform the method according to any one of claims 1-9, characterized in that, include: Diamond wire (201) is used to cut crystals (30); Tension controller (202) is used to control the running tension of diamond wire (201); A wire diameter detector (203) is used to detect the real-time wire diameter of the diamond wire (201); A cutting system (204) is used to drive the diamond wire (201) to perform a cutting action; The PLC system (10) is connected to the tension controller (202), wire diameter detector (203), and cutting system (204) to collect data and regulate the operating status of the diamond wire (201).

Images