A ceramic tray for processing of SiC ingots and a method of using the same

Abstract

The application belongs to the field of semiconductor material processing, and particularly relates to a ceramic tray for SiC crystal ingot processing and a use method thereof, and aims to solve the problems of easy edge collapse, poor compatibility, more processing excess material of thin crystal ingot and inconvenient information tracing in the prior art that the crystal ingot is directly adsorbed on a vacuum chuck. The ceramic tray comprises a tray body, the tray body is in a disc structure, the back surface of the tray body is a flat adsorption surface, and the front surface of the tray body is an adhesive area for carrying the SiC crystal ingot; a detachable positioning ring is arranged at the edge of the front surface of the tray body, and a digital number is screen-printed at the edge of the adhesive area; an asymmetric positioning groove is processed at the edge of the adsorption surface, and a two-dimensional code is etched at the center of the adsorption surface. The ceramic tray can realize compatibility of different specifications and sizes of crystal ingots, contactless processing of equipment, improvement of product process capability index (Cpk), reduction of SiC crystal ingot processing edge and corner material remaining amount, and improvement of thin crystal ingot processing performance and material utilization.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor material processing, specifically relating to a ceramic tray for SiC ingot processing and its usage method. Background Technology

[0002] In strategic emerging fields such as new energy vehicles, rail transportation, high-voltage power transmission and transformation, and satellite communications, third-generation semiconductor devices, with their high-temperature resistance, high power density, and radiation resistance, are driving rapid technological iteration. As a core supporting material, SiC substrates, with their high power density, low heat loss, and lattice matching advantages with gallium nitride, have become an ideal choice for high-power microwave RF devices and high-voltage power electronic devices. In SiC substrate processing, laser lift-off technology, as an emerging method, is gradually replacing traditional wire cutting to achieve efficient ingot slicing.

[0003] Currently, most mature laser lift-off equipment typically requires SiC ingots to be adsorbed and fixed onto a vacuum chuck for operation. However, due to minor unevenness on the bottom surface of the ingot itself or errors on the surface of the vacuum chuck, an angle may form between the ingot and the chuck. Under the action of adsorption force, local stress concentration occurs at the edge of the ingot, which can easily lead to "edge chipping" defects, resulting in material loss and reduced yield.

[0004] Furthermore, existing fixing methods typically act directly on the ingot, requiring different suction cups or clamps for ingots of different sizes, resulting in poor compatibility and low switching efficiency. Processing thinner ingots is particularly difficult, as the adsorption and fixation are unstable, and to ensure processing safety and prevent puncture, a significant amount of excess material is often required, reducing the effective utilization rate of the material. Simultaneously, in batch processing, accurate and rapid identification and traceability of the ingot's identity information are crucial for process control and quality management. Summary of the Invention

[0005] This invention addresses the problems in existing technologies where direct adsorption of ingots onto vacuum chucks easily leads to edge chipping, poor compatibility, excessive waste material during thin ingot processing, and inconvenient information traceability. It provides a ceramic tray for SiC ingot processing. This tray enables compatibility with ingots of different sizes, non-contact processing, improved product process capability index (Cpk), and reduced waste material from SiC ingot processing.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: a ceramic tray for SiC ingot processing, comprising a tray body, the tray body having a disc-shaped structure, a flat adsorption surface on its back side, and an adhesive area for supporting SiC ingots on its front side; a detachable positioning ring is provided on the edge of the front side of the tray body, and a number is laser-marked on the edge of the adhesive area; an asymmetric positioning groove is processed on the edge of the adsorption surface, and a QR code is etched at the center of the adsorption surface.

[0007] As a further limitation of the technical solution of the present invention, the tray body is made of white alumina ceramic.

[0008] As a further limitation of the technical solution of the present invention, the size of the bonding area is greater than 8 inches.

[0009] As a further limitation of the technical solution of the present invention, the positioning ring is a circular ring structure, which has three annular steps with different diameters inside, namely step one, step two and step three in sequence. The diameter of step one matches the tray body to ensure that the positioning ring and the tray body are coaxial; the diameter of step three matches the crystal ingot size to ensure that the crystal ingot and the positioning ring are coaxial.

[0010] In addition, the present invention also provides a method for using the ceramic tray for SiC ingot processing, comprising the following steps: S1. Preheating and Waxing Place the ceramic tray on a heating plate and heat it to the melting temperature of the adhesive wax; apply a layer of molten adhesive wax evenly to the bonding area on the front of the tray; S2, Ingot Fixing Place the SiC ingot on the bonding area coated with adhesive wax, and press lightly to ensure that the bottom surface of the ingot is in full contact with the adhesive wax and to remove air bubbles. S3, cooling and solidification Stop heating and allow the adhesive wax to cool and solidify naturally, thereby firmly bonding and fixing the SiC ingot to the ceramic tray to form an integral "tray-ingot" composite. S4. Processing and Information Traceability The "tray-ingot" composite is transferred to the worktable of the laser lifter, so that the adsorption surface on the back of the ceramic tray is tightly attached to the vacuum suction cup of the equipment, and vacuum adsorption and fixation are initiated; before processing, information is associated and traced by identifying the digital number on the front of the tray or scanning the QR code on the back; then, the SiC ingot is processed. S5. Separation and Recycling After processing, the "tray-ingot" composite is heated to melt the adhesive wax, thereby removing the processed ingot and remaining material from the ceramic tray. The surface of the ceramic tray is cleaned with alcohol solvent to remove residual wax, and after drying, the ceramic tray can be reused.

[0011] Compared with the prior art, the present invention has the following beneficial effects: 1. Anti-chipping and contactless processing: By introducing a ceramic tray as an intermediate medium, the SiC ingot is placed on the tray, and the back of the tray is held in place by a vacuum chuck. This method achieves no direct contact between the ingot and the processing equipment, avoiding local stress concentration caused by the tilt angle between them, thus effectively solving the problem of "chipping" at the ingot edge and improving the processing yield.

[0012] 2. Multi-size compatibility: The tray design is compatible with a variety of mainstream SiC ingot sizes, which simplifies the tooling change process required for switching ingot specifications on the production line, and improves equipment utilization and production flexibility.

[0013] 3. Information Traceability: The clear, visible numerical code on the front of the tray facilitates quick identification and verification by operators. The QR code on the back can be linked to and entered with key information such as the batch number, serial number, and process parameters of the ingots. This information can be quickly read by a barcode scanner, ensuring traceability of the processing process and providing a foundation for stable process capability control.

[0014] 4. Improved processing performance and material utilization of thin ingots: For thin SiC ingots that are difficult to directly and stably adsorb and process, the tray of this invention increases the overall load-bearing thickness and rigidity, making vacuum adsorption more secure. This allows for a significant reduction in the safety margin reserved to prevent processing penetration when formulating processing procedures, thereby reducing the loss of individual wafers and improving the overall utilization rate of valuable SiC materials.

[0015] 5. Material advantages: Made of white ceramic material, it has advantages such as high hardness, high wear resistance, corrosion resistance, good insulation, and easy-to-ensure surface flatness. In addition, the white background is conducive to the clear presentation and recognition of numerical serial numbers and QR codes. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the front structure of the ceramic tray of the present invention.

[0017] Figure 2 This is a schematic diagram of the back structure of the ceramic tray of the present invention.

[0018] Figure 3 This is a schematic diagram of the "tray-crystal ingot" composite after bonding according to the present invention.

[0019] Figure 4 This is a cross-sectional schematic diagram of the ceramic tray of the present invention supporting the crystal ingot and placed on a vacuum suction cup in its usage state.

[0020] Figure 5 This is a schematic diagram of the positioning ring of the present invention.

[0021] Figure 6 This is a top view of the positioning ring of the present invention.

[0022] Figure 7 for Figure 6 AA sectional view.

[0023] Figure 8 This is a schematic diagram showing the connection and use of the SiC ingot, tray body, and positioning ring.

[0024] Figure 9 for Figure 8 AA sectional view.

[0025] The markings in the image are as follows: 1-Tray body; 2-Number number; 3-Adhesive area; 4-Adsorption surface; 5-Positioning groove; 6-QR code; 7-SiC crystal ingot; 8-Vacuum suction cup; 9-Positioning ring; 91-Step 1; 92-Step 2; 93-Step 3. Detailed Implementation

[0026] The present invention will be further described below with reference to specific embodiments. Example 1

[0027] like Figure 1-3 As shown, a ceramic tray for SiC ingot processing includes a tray body 1, which is a disc-shaped structure made of high-strength white alumina ceramic. The back of the tray body 1 has a flat adsorption surface 4 for close contact with the surface of a vacuum suction cup. The front of the tray body 1 has an adhesive area 3 for supporting the SiC ingot. This area is designed as a flat region with a diameter slightly larger than an 8-inch ingot, and is surrounded by detachable positioning rings of different sizes, enabling rapid positioning and compatibility with ingots of different sizes. The edge of the adhesive area 3 is laser-marked with a numerical code 2 for rapid visual identification. An asymmetric positioning groove 5 is machined along the edge of the adsorption surface 4, and a QR code 6 is etched at the center of the adsorption surface 4, containing tray and ingot identification information.

[0028] Furthermore, such as Figure 5-7 As shown, the positioning ring 9 is a circular ring structure with three annular steps of different diameters inside: step one 91, step two 92, and step three 93. The diameter of step one 91 matches the size of the tray body 1, ensuring that the positioning ring and the tray body 1 are coaxial. The diameter of step three 93 matches the size of the ingot, ensuring that the ingot and the positioning ring are coaxial. This method ensures that the ingot is centered on the ceramic plate during bonding. Step two 92 is used to avoid the applied wax, preventing the positioning ring 9 from bonding to the tray body 1. During bonding, as... Figure 8-9 As shown, after placing the crystal ingot on the tray body 1, the positioning ring 9 is then placed on top to position the crystal ingot on the tray body 1. After the wax liquid cools, the positioning ring 9 is removed.

[0029] The positioning groove 5 serves two purposes: firstly, it coordinates with the processing equipment to ensure precise positioning and circumferential anti-rotation of the pallet, guaranteeing consistent pallet positioning throughout all stages; secondly, its asymmetrical shape prevents the pallet from fitting snugly against the equipment if incorrectly placed face down, thus providing physical error prevention. This ensures that the robotic arm can only place the pallet in the correct orientation during natural handling, fundamentally preventing processing accidents or ingot damage caused by incorrect orientation.

[0030] The bonding area 3 is designed to be compatible with bonding SiC ingots of different sizes, such as 4-inch, 6-inch and 8-inch, without replacing the tray, through an adaptable structure.

[0031] The ceramic tray body is 10mm thick. Through optimized design, when it carries a thin SiC ingot and is adsorbed onto the vacuum chuck, it can increase the overall rigidity and thickness of the assembly, making the vacuum adsorption more stable and reliable. This allows for a reduction in the amount of ingot residue reserved for safety during processing, thereby improving material utilization.

[0032] The working process and principle of the above-mentioned ceramic tray are as follows: First, perform the fixing operation: place the tray on the adjustable temperature heating plate and heat it to 60-80℃; apply solid adhesive wax to the bonding area 3 and let it melt into a uniform wax liquid when heated; place the SiC crystal ingot 7 stably on the wax liquid, apply slight pressure and adjust its position, and let it stand and cool to room temperature. The adhesive wax solidifies, firmly bonding the crystal ingot to the tray to form a composite.

[0033] Then, the processing operation is performed: the composite is transferred to the vacuum chuck 8 of the slicing machine, so that the adsorption surface 4 on the back of the tray is in contact with the chuck, and vacuum adsorption is initiated. At this time, the processing equipment processes the ingot 7, and the ingot has no direct contact with the vacuum chuck 8.

[0034] By scanning QR code 6 with a scanner, all process information of the crystal ingot can be retrieved, enabling full-process monitoring. After processing, the tray can be separated from the crystal ingot (or remaining material) by heating and melting the adhesive wax. The tray can be cleaned and reused. Example 2

[0035] A method of using a ceramic tray for SiC ingot processing includes the following steps: S1. Preheating and Waxing Place the ceramic tray on a heating plate and heat it to the melting temperature of the adhesive wax; apply a layer of molten adhesive wax evenly to the bonding area 3 on the front of the tray; S2, Ingot Fixing Place the SiC ingot on the bonding area 3 coated with adhesive wax, and press lightly to ensure that the bottom surface of the ingot is in full contact with the adhesive wax and to remove air bubbles. S3, cooling and solidification Stop heating and allow the adhesive wax to cool and solidify naturally, thereby firmly bonding and fixing the SiC ingot to the ceramic tray to form an integral "tray-ingot" composite. S4. Processing and Information Traceability The "tray-ingot" composite is transferred to the worktable of the laser lifter, so that the adsorption surface 4 on the back of the ceramic tray is tightly attached to the vacuum suction cup of the equipment, and vacuum adsorption is started for fixation. Before processing, information is associated and traced by identifying the digital number 2 on the front of the tray or scanning the QR code 6 on the back. Subsequently, the SiC ingot is processed. S5. Separation and Recycling After processing, the "tray-ingot" composite is heated to melt the adhesive wax, thereby removing the processed ingot and remaining material from the ceramic tray. The surface of the ceramic tray is cleaned with alcohol solvent to remove residual wax, and after drying, the ceramic tray can be reused.

Claims

1. A ceramic tray for processing SiC ingots, characterized in that, The tray body (1) is a disc-shaped structure with a flat adsorption surface (4) on its back and an adhesive area (3) on its front for supporting SiC ingots. A detachable positioning ring (9) is provided on the edge of the front of the tray body (1), and a number (2) is laser-marked on the edge of the adhesive area (3). An asymmetric positioning groove (5) is processed on the edge of the adsorption surface (4), and a QR code (6) is etched at the center of the adsorption surface (4).

2. A ceramic tray for SiC ingot processing according to claim 1, characterized in that, The tray body (1) is made of white alumina ceramic.

3. A ceramic tray for SiC ingot processing according to claim 1, characterized in that, The adhesive area (3) is larger than 8 inches.

4. A ceramic tray for SiC ingot processing according to claim 1, characterized in that, The positioning ring (9) is a circular ring structure with three ring-shaped steps of different diameters inside, namely step one (91), step two (92), and step three (93). The diameter of step one (91) matches the size of the tray body 1 to ensure that the positioning ring is coaxial with the tray body 1; the diameter of step three (93) matches the size of the crystal ingot to ensure that the crystal ingot is coaxial with the positioning ring.

5. A method of using a ceramic tray for SiC ingot processing according to any one of claims 1-4, characterized in that, Includes the following steps: S1. Preheating and Waxing Place the ceramic tray on a heating plate and heat it to the melting temperature of the adhesive wax; apply a layer of molten adhesive wax evenly to the bonding area (3) on the front of the tray; S2, Ingot Fixing Place the SiC ingot on the bonding area (3) coated with adhesive wax, and press lightly to ensure that the bottom surface of the ingot is in full contact with the adhesive wax and to remove air bubbles; S3, cooling and solidification Stop heating and allow the adhesive wax to cool and solidify naturally, thereby firmly bonding and fixing the SiC ingot to the ceramic tray to form an integral "tray-ingot" composite. S4. Processing and Information Traceability The "tray-ingot" composite is transferred to the worktable of the laser stripping equipment, so that the adsorption surface (4) on the back of the ceramic tray is tightly attached to the vacuum suction cup of the equipment, and vacuum adsorption is started for fixation; before processing, information is associated and traced by identifying the digital number (2) on the front of the tray or scanning the QR code (6) on the back; then, the SiC ingot is processed. S5. Separation and Recycling After processing, the "tray-ingot" composite is heated to melt the adhesive wax, thereby removing the processed ingot and remaining material from the ceramic tray. The surface of the ceramic tray is cleaned with alcohol solvent to remove residual wax, and after drying, the ceramic tray can be reused.

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