Cutting method of silicon carbide wafer
By employing a multi-step method involving cutting, grinding, and laser ablation of silicon carbide wafers, the problems of low efficiency and warping in existing technologies have been solved, enabling efficient and high-quality silicon carbide wafer manufacturing.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-22
- Publication Date
- 2026-03-13
AI Technical Summary
Existing silicon carbide wafer dicing methods are inefficient and prone to warping, and the dicing process is complex, affecting the dicing quality.
A multi-step approach is employed, including ingot cutting, grinding, and laser lift-off. Wafer thinners and laser lift-off equipment are used in combination with diamond wire or smooth steel wire cutting to ensure wafer thickness consistency and avoid warping.
It improves the manufacturing efficiency and quality of silicon carbide wafers, reduces warpage, and enhances material utilization and equipment output efficiency.
Smart Images
Figure CN121650132A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of wafer technology, and in particular to a method for dicing silicon carbide wafers. Background Technology
[0002] Silicon carbide wafer dicing involves separating a silicon carbide ingot into multiple wafers using processes such as diamond wire cutting. However, existing silicon carbide wafer dicing methods require multiple steps and are complex, resulting in low dicing efficiency and poor quality of the diced silicon carbide wafers. Summary of the Invention
[0003] This application proposes a method for dicing silicon carbide wafers to improve dicing efficiency and ensure dicing quality.
[0004] To achieve the above objectives, this application discloses the following technical solutions:
[0005] A method for dicing a silicon carbide wafer, comprising:
[0006] S1: Cut the crystal rod to obtain multiple wafers of equal thickness to be ground;
[0007] S2: Grind the front and back sides of the wafer to be ground to obtain a polished wafer;
[0008] S3: The polished wafer is separated by laser cutting to obtain two target wafers.
[0009] In some technical solutions, the cutting method further includes:
[0010] The back side of the first target wafer is ground to obtain a ground target wafer, and the front side of the second target wafer is ground to obtain a ground target wafer; wherein the back side of the first target wafer and the front side of the second target wafer are opposite peeling surfaces.
[0011] In some technical solutions, step S4 includes: using the chuck of a wafer thinner to adsorb the front side of the first target wafer, and using the grinding wheel of the wafer thinner to grind the back side of the first target wafer to obtain a polished target wafer; using the chuck of a wafer thinner to adsorb the back side of the second target wafer, and using the grinding wheel of the wafer thinner to grind the front side of the first target wafer to obtain a polished target wafer.
[0012] In some technical solutions, the cutting method further includes:
[0013] Several silicon carbide crystals are bonded together to form the crystal rod.
[0014] In some technical solutions, step S3 includes: using a laser stripping device to cut and strip the polished wafer to obtain two target wafers;
[0015] Wherein, the laser focusing depth of the laser stripping device is H, and the thickness of the polishing wafer is 2H.
[0016] In some technical solutions, step S2 includes: using the grinding wheel of a wafer thinner to grind the front and back sides of the wafer to be ground to obtain a polished wafer.
[0017] In some technical solutions, step S1 includes: cutting the crystal rod, and then removing the cut crystal rod from the adhesive to obtain multiple wafers of equal thickness to be ground.
[0018] In some technical solutions, the diameter of the crystal rod is 2 inches, 3 inches, 4 inches, 6 inches, 8 inches, or 12 inches.
[0019] In some technical solutions, multiple cutting machines are used to cut the crystal rod;
[0020] The groove pitch of the grooved wheel of the multi-stage cutting machine can be 300μm-2000μm, and the diameter of the cutting line of the multi-stage cutting machine can be 20μm-200μm.
[0021] In some technical solutions, the cutting wire is diamond wire or smooth steel wire.
[0022] The above technical solution illustrates a method for cutting silicon carbide wafers. A crystal rod is cut to obtain a wafer to be ground. The surface of the wafer is then ground to obtain a polished wafer, thus preventing warping of the silicon carbide wafer. Finally, the polished wafer is laser-cut to remove the target wafer, ensuring rapid manufacturing of silicon carbide wafers. By following the first to third steps, silicon carbide wafers can be obtained quickly, significantly improving manufacturing efficiency. Attached Figure Description
[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort, and this application can be applied to other similar scenarios based on the provided drawings, all of which fall within the scope of protection of this invention. Unless obvious from the linguistic context or otherwise specified, the same reference numerals in the drawings represent the same structure or operation.
[0024] Figure 1A flowchart illustrating the silicon carbide wafer cutting method provided in this application embodiment;
[0025] Figure 2 This is a schematic diagram of a silicon carbide wafer cutting method provided in an embodiment of this application;
[0026] in:
[0027] 10 is a crystal rod; 20 is the wafer to be ground; 30 is the wafer to be ground; 40 is the target wafer; 50 is the target wafer to be ground; and 60 is a grinding wheel. Detailed Implementation
[0028] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are merely illustrative of the application and not intended to limit it. The described embodiments are only a part of the embodiments of the present application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without inventive effort are within the scope of protection of the present application.
[0029] Existing silicon carbide wafer dicing methods suffer from low dicing efficiency and wafer warping issues. Figure 1 and Figure 2 As shown, this application provides a method for cutting silicon carbide wafers.
[0030] S1: Cut the crystal rod 10 to obtain multiple wafers 20 of equal thickness to be ground.
[0031] S2: Grind the front and back sides of the wafer 20 to be ground to obtain the polished wafer 30; wherein the front and back sides of the wafer 20 to be ground are two opposite sides; wherein the grinding amount can be 0.5 μm.
[0032] S3: Two target wafers 40 are obtained by laser cutting and peeling off the polished wafer 30.
[0033] In this technical solution, the crystal ingot 10 is first cut to obtain the wafer to be polished 20. Then, the surface of the wafer to be polished 20 is polished to obtain the polished wafer 30 (i.e., the polished wafer) to avoid the problem of warping of the silicon carbide wafer. Finally, the polished wafer 30 is laser-cut and peeled to obtain the target wafer 40 to ensure the rapid manufacturing of silicon carbide wafers. By going through the first to third steps, silicon carbide wafers can be obtained quickly, which greatly improves the manufacturing efficiency of silicon carbide wafers.
[0034] To further avoid warping issues in silicon carbide wafers and improve wafer processing yield, such as Figure 2 As shown, the cutting method also includes:
[0035] The back side of the first target wafer 40 is ground to obtain the ground target wafer 50, and the front side of the second target wafer 40 is ground to obtain the ground target wafer 50; wherein the back side of the first target wafer 40 and the front side of the second target wafer 40 are opposite peeling surfaces; wherein the grinding amount can be 0.5 μm.
[0036] In the above technical solution, the front side of the first target wafer 40, which is the front side of the wafer 20 to be polished, has already been polished, and the back side of the second target wafer 40, which is the back side of the wafer 20 to be polished, has already been polished. In this technical solution, the back side of the first target wafer 40 and the front side of the second target wafer 40 are polished again to ensure the quality of the target wafer 40.
[0037] In order to quickly grind the target wafer 40 to obtain the ground target wafer 50, the front side of the first target wafer 40 is adsorbed by the chuck of the wafer thinner and the back side of the first target wafer 40 is ground by the grinding wheel 60 of the wafer thinner to obtain the ground target wafer 50; the back side of the second target wafer 40 is adsorbed by the chuck of the wafer thinner and the front side of the first target wafer 40 is ground by the grinding wheel 60 of the wafer thinner to obtain the ground target wafer 50.
[0038] In the above technical solution, a suction cup can be used to quickly adsorb the side of the target wafer 40 that does not need to be polished, thereby improving the polishing efficiency.
[0039] Of course, cutting methods also include:
[0040] Several silicon carbide crystals are bonded together to form a crystal rod 10.
[0041] In the above technical solution, several silicon carbide crystals are bonded together to form a crystal rod 10, which can make full use of small-sized or locally defect-free crystal blanks and greatly improve the material utilization rate.
[0042] In order to quickly obtain two target wafers 40, a laser stripping device is used to cut and strip the polished wafer 30 to obtain two target wafers 40.
[0043] The laser focusing depth of the laser stripping equipment is H, and the thickness of the polishing wafer 30 is 2H.
[0044] In the above technical solution, the polished wafer 30 can be quickly divided into two to obtain the target wafer 40.
[0045] To obtain the polished wafer 30, step S2 includes: polishing the front and back sides of the wafer 20 to be polished using the grinding wheel 60 of the wafer thinner, thereby obtaining the polished wafer 30. In this technical solution, if the front side of the wafer 20 to be polished is polished, the back side of the wafer 20 to be polished is adsorbed and fixed using the chuck of the wafer thinner; if the back side of the wafer 20 to be polished is polished, the front side of the wafer 20 to be polished is adsorbed and fixed using the chuck of the wafer thinner.
[0046] To ensure wafer quality, step S1 includes: cutting the crystal ingot 10, and then removing the cut crystal ingot 10 from the substrate to obtain multiple wafers 20 of equal thickness to be polished. In this technical solution, the core function of removing the substrate is to separate the wafers that are still attached to the carrier after cutting from the carrier, while ensuring the integrity and thickness consistency of the wafers to be polished.
[0047] In this technical solution, the diameter of the crystal rod 10 can be 2 inches, 3 inches, 4 inches, 6 inches, 8 inches or 12 inches, depending on the actual production needs.
[0048] In one technical solution, multiple cutting machines are used to cut the crystal rod 10;
[0049] The groove pitch of the grooved wheel of a multi-stage cutting machine can be 300μm-2000μm, and the diameter of the cutting line can be 20μm-200μm to ensure cutting quality.
[0050] To further ensure cutting quality, the cutting wire is made of diamond wire or smooth steel wire. Both the diamond wire and smooth steel wire are spiral-structured cutting wires.
[0051] In one technical solution, the laser stripping equipment is a laser cutting machine. The laser used in the laser cutting machine has a power range of 0.5W to 50W and a wavelength range of 532nm to 1064nm. The laser beam scanning spacing can range from 0.1mm to 0.6mm, and the scanning time ranges from 10min to 60min.
[0052] In one technical solution, the wafer thinning machine grinds silicon carbide wafers using a grinding wheel 60. The feed rate of the wafer thinning machine can range from 0.1 to 0.6 μm / s, the rotation speed of the grinding wheel 60 can range from 1000 rpm to 3000 rpm, and the mesh size of the grinding wheel 60 can range from 800 mesh to 60000 mesh.
[0053] In a specific technical solution, the target thickness of the grinding target wafer 50 is T μm, the wafer thickness for laser cutting is set to d μm (d > T), and the thickness of the wafer 20 to be ground after multi-wire cutting is (2d + m) μm (0 < m < d, where m is the amount of material removed by grinding and polishing before laser cutting of the multi-wire slice). Based on the preset multi-wire slice thickness (2d + m) μm, a main roller with a suitable groove pitch, a steel wire of a suitable diameter, and cutting fluid are selected. The main roller is installed on the multi-wire cutting machine, and after the wire mesh is wound and laid out, the silicon carbide crystal rod is placed... Multi-wire cutting is performed on a prepared multi-wire dicing machine. After cutting, the cut crystal is removed from the multi-wire dicing machine, debonded and unloaded. The silicon carbide multi-wire slices are cleaned to remove wafers with inconsistent thicknesses at the beginning and end, resulting in a wafer 20 with uniform thickness of (2d+m) μm to be ground. The wafer 20 to be ground is then ground to obtain a grinding wafer 30. The grinding wafer 30 is then separated using laser cutting to obtain two target wafers 40. These are then thinned to obtain two grinding target wafers 50 with a thickness of T μm.
[0054] In this technical solution, multi-wire cutting uses smaller diameter steel wires to cut thicker wafers. The thicker wafers themselves have better rigidity and are less affected by the cutting mechanical action, thermal stress, and fluctuations in the steel wire. This effectively avoids warping problems caused by multi-wire cutting of thin wafers. Multiple wafers of uniform thickness can be obtained in one cut. Laser cutting produces wafers with less warping, but only one wafer is processed at a time, resulting in low equipment output efficiency. By laser cutting a multi-wire wafer of a certain thickness, it can be divided into two, resulting in two laser wafers at the same time, which greatly improves the output efficiency of the laser cutting equipment (doubles the efficiency).
[0055] In the above context, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.
[0056] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. "And / or" in this article is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone.
[0057] It should be noted that, for ease of description, only the parts relevant to the application are shown in the accompanying drawings. Unless otherwise specified, the embodiments and features described in this application can be combined with each other.
[0058] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed, and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. The scope of this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described application concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.
Claims
1. A method for dicing silicon carbide wafers, characterized in that, include: S1: Cut the crystal rod (10) to obtain multiple wafers (20) of equal thickness to be ground. S2: Grind the front and back sides of the wafer to be ground (20) to obtain a polished wafer (30). S3: The polished wafer (30) is laser-cut and peeled to obtain two target wafers (40).
2. The cutting method as described in claim 1, characterized in that, The cutting method further includes: The back side of the first target wafer (40) is ground to obtain a ground target wafer (50), and the front side of the second target wafer (40) is ground to obtain a ground target wafer (50); wherein the back side of the first target wafer (40) and the front side of the second target wafer (40) are opposite peeling surfaces.
3. The cutting method as described in claim 2, characterized in that, Step S4 includes: using the chuck of the wafer thinner to pick up the front side of the first target wafer (40), and using the grinding wheel (60) of the wafer thinner to grind the back side of the first target wafer (40) to obtain a ground target wafer (50); using the chuck of the wafer thinner to pick up the back side of the second target wafer (40), and using the grinding wheel (60) of the wafer thinner to grind the front side of the first target wafer (40) to obtain a ground target wafer (50).
4. The cutting method as described in claim 1, characterized in that, The cutting method further includes: Several silicon carbide crystals are bonded together to form the crystal rod (10).
5. The cutting method as described in claim 1, characterized in that, The S3 step includes: using a laser stripping device to cut and strip the polished wafer (30) to obtain two target wafers (40); Wherein, the laser focusing depth of the laser stripping device is H, and the thickness of the polishing wafer (30) is 2H.
6. The cutting method as described in claim 1, characterized in that, The S2 step includes: using the grinding wheel (60) of the wafer thinner to grind the front and back sides of the wafer to be ground (20) to obtain the ground wafer (30).
7. The cutting method as described in claim 1, characterized in that, The S1 step includes: cutting the crystal rod (10), and then removing the cut crystal rod (10) from the adhesive to obtain multiple wafers (20) of equal thickness to be ground.
8. The cutting method as described in claim 1, characterized in that, The diameter of the crystal rod (10) is 2 inches, 3 inches, 4 inches, 6 inches, 8 inches or 12 inches.
9. The cutting method as described in claim 1, characterized in that, The crystal rod (10) was cut using a multi-stage cutting machine; The groove pitch of the grooved wheel of the multi-stage cutting machine can be 300μm-2000μm, and the diameter of the cutting line of the multi-stage cutting machine can be 20μm-200μm.
10. The cutting method as described in claim 9, characterized in that, The cutting wire is a diamond wire or a smooth steel wire.