ith the continuous development of GaN devices, optoelectronic devices, and semiconductor substrate applications, sapphire substrates are moving rapidly toward larger sizes, higher material utilization, and greater consistency. When yield remains comparable, larger sapphire crystals can improve material utilization and enhance the overall cost efficiency of downstream device manufacturing.

Today, the industry is gradually shifting from traditional small-size substrates to larger specifications such as 8-inch and 12-inch wafers. As a result, the processing capability for large-size sapphire substrates is becoming an important technical reserve for material manufacturers and substrate processing companies.

However, upgrading substrate size is not simply a matter of “making the crystal larger.” For 12-inch sapphire ingots, the high hardness, strong brittleness, and large dimensions of the material significantly increase the difficulty of stress control, damage control, and deformation control during cutting. From irregular ingots to standard substrate wafers, front-end processing must go through ingot cropping, cylindrical shaping, and multi-wire slicing. Each process directly affects final yield as well as the cost of subsequent grinding and polishing.

In the cropping stage, both cutting efficiency and blank integrity must be considered to avoid edge chipping and material waste. In the shaping stage, roundness, coaxiality, and edge quality must be controlled to establish a stable geometric reference for subsequent slicing. In the slicing stage, thickness consistency, TTV, warpage, and surface appearance are directly determined. For large-size specifications such as 12-inch sapphire, simply being able to cut the material is no longer enough. The real process challenge lies in achieving stable, accurate, low-damage, and highly consistent cutting over time.

Donghe Solution: Coordinated Loop Wire, Single Wire, and Multi-Wire Cutting for Front-End Processing

To address the challenge of balancing efficiency, precision, and consistency in 12-inch sapphire substrate processing, Donghe Technology provides a complete diamond wire cutting solution covering the core front-end processes. The solution follows the process route of “ingot cropping — cylindrical shaping — multi-wire slicing,” with loop wire cutting machines, reciprocating single wire cutting machines, and multi-wire cutting machines configured respectively to connect each processing stage.

Compared with a single-equipment processing model, Donghe Technology places greater emphasis on coordinated line integration. The loop wire cutting machine is used for efficient ingot cropping, improving the cutting efficiency of large-size ingots. The reciprocating single wire cutting machine is used for high-precision cylindrical shaping, establishing a stable geometric reference for subsequent slicing. The multi-wire cutting machine is used for batch wafer slicing, ensuring thickness consistency, surface quality, and processing stability.

Step 1: Ingot Cropping — Efficient Material Cutting with Loop Wire Cutting Machine

For 12-inch sapphire ingots, which are large in size, high in hardness, and difficult to cut, Donghe Technology adopts a horizontal loop diamond wire cutting machine for efficient cropping. This process is mainly used to remove defective head and tail sections of the ingot, complete ingot segmentation, and provide a stable blank foundation for subsequent shaping and slicing.

Compared with traditional reciprocating single wire cutting, loop wire cutting offers the advantages of larger wire diameter, higher wire speed, and higher cutting efficiency, making it more suitable for rapid cropping of large-size sapphire ingots. According to Donghe’s verified data, in the cropping of 12-inch sapphire ingots, the wire speed can reach 3,000 m/min, with a processing time of approximately 150 minutes. Compared with the approximately 400-minute processing time of the reciprocating single wire solution, this can significantly shorten the front-end processing cycle.

Step 2: Cylindrical Shaping — Establishing a High-Precision Reference with Reciprocating Single Wire Cutting

After ingot cropping, cylindrical shaping determines the geometric reference for subsequent multi-wire slicing. If the sapphire ingot has insufficient roundness or unstable coaxiality, it will not only increase the pressure of later grinding processes but also affect force uniformity and batch stability during slicing.

Donghe Technology’s reciprocating single diamond wire cutting machine features high-precision single wire cutting, large wire storage capacity, and fine tension control. It can achieve sapphire ingot skin removal, cylindrical cutting, roundness control, and continuous processing. In the shaping application of Φ370 × 150 mm sapphire ingots, Donghe’s reciprocating single wire solution can control roundness tolerance within 0.1 mm. At the same time, wire cost is significantly reduced compared with loop wire cutting, providing a more stable and more economical cylindrical ingot foundation for subsequent 12-inch multi-wire slicing.

Step 3: Multi-Wire Slicing — Stable Batch Processing for 12-Inch Substrates

The final value of 12-inch sapphire substrates largely depends on the multi-wire slicing process. This stage must not only ensure cutting efficiency but also control thickness consistency, TTV, warpage, surface quality, and batch yield.

Donghe Technology’s multi-wire cutting machine relies on a stable wire web system, high-speed wire processing capability, and continuous cutting performance to achieve highly consistent slicing of 12-inch sapphire ingots. According to Donghe’s verified data, the processing time for φ305 sapphire slicing is 18 hours, with a thickness tolerance of 1.25 +0.025 mm, a same-wafer TTV variation of 0.017 mm, and warpage of 40 μm. The wafer appearance meets requirements including no visible wire marks or uneven surface feel, no edge chipping, and no cracking. These results demonstrate the equipment’s stable processing capability in large-size sapphire slicing.

From Equipment Selection to Process Introduction, Supporting the Upgrade of 12-Inch Sapphire Cutting

Through the combined matching of equipment and process technology, Donghe Technology provides a systematic solution for 12-inch sapphire substrate processing, upgrading the process from “cuttable” to “stable, accurate, and efficient cutting.” From ingot cropping and cylindrical shaping to 12-inch multi-wire slicing, the loop wire cutting machine, reciprocating single wire cutting machine, and multi-wire cutting machine form a complete product portfolio, providing more efficient, stable, and industrialized front-end cutting support for large-size sapphire substrate processing.

For material manufacturers, substrate processing companies, and research institutions that are planning or expanding into 8-inch and 12-inch sapphire substrates, Donghe Technology can provide not only equipment selection support, but also trial cutting verification, process optimization, equipment customization, commissioning training, and continuous technical support based on each customer’s material characteristics, processing targets, and production line requirements.

From single-machine equipment to integrated line coordination, and from process verification to batch introduction, Donghe Technology is committed to working with more sapphire substrate enterprises to promote the processing upgrade of large-size hard and brittle materials, enabling 12-inch sapphire substrate cutting to become truly more achievable, more accurate, more stable, and more efficient.