Surface Modification of Semiconductor Graphite Boats: Thermal Spraying of Yttria and Zirconia

In the semiconductor manufacturing process, graphite boats face severe challenges from high-temperature oxidation. This leads to reduced product yield and shortened equipment life. Thermal spraying technology provides a solution with yttria (Y₂O₃) and zirconia (ZrO₂) coatings, significantly enhancing the high-temperature resistance and anti-oxidation performance of graphite boats, offering durable and reliable protection for critical processes in the semiconductor industry.

Surface Modification Needs and Challenges for Graphite Boats

Graphite boats are widely used in high-temperature processing steps in semiconductor manufacturing, such as melting, annealing, and diffusion. In these applications, graphite materials face the following challenges:

• High-Temperature Oxidation: Although graphite has high thermal resistance, it oxidizes easily in oxidative atmospheres, leading to material loss.
• Chemical Corrosion: Chemical substances during semiconductor processing may erode the graphite surface, affecting its lifespan and process stability.
• Particle Contamination: The natural surface of graphite can release particles, contaminating semiconductor devices.

To address these challenges, surface modification has become a key solution. Ceramic coatings, particularly noted for their high-temperature resistance, chemical stability, and anti-oxidation properties, have gained attention as they provide better protection than traditional graphite materials.

Analysis of Ceramic Thermal Spraying Technology

Ceramic thermal spraying is a surface treatment technique that involves melting ceramic materials at high temperatures and spraying them onto the substrate surface. Its core principles include:

Process Principles:

Using plasma spraying technology, yttria or zirconia ceramic materials in powder form are heated to a molten state and sprayed onto the surface of graphite boats at high speed, forming a dense coating.

Key Process Points:

• Temperature Control: Ensuring the ceramic powders reach the melting temperature to create coatings with high adhesion and low porosity.
• Uniform Coating: Optimizing spraying parameters to achieve uniform coating thickness, improving surface wear resistance and lifespan.

Advantages Over Traditional Methods:

• Higher Temperature Resistance: Ceramic coatings have significantly better temperature resistance compared to untreated graphite materials.
• Reduced Particle Shedding: Ceramic coatings effectively reduce particle shedding, minimizing contamination risks.
• Extended Lifespan: Improved anti-oxidation performance and effective defense against chemical corrosion.

Performance Advantages of Y₂O₃ and ZrO₂ Ceramic Coatings

Different ceramic materials have their unique advantages, and selecting the right coating material is crucial for success. Yttria and zirconia demonstrate distinct benefits in semiconductor environments.

1. Yttria (Y₂O₃) Coating:

• Excellent Anti-Oxidation: Y₂O₃ effectively slows oxidation rates, extending the lifespan of graphite substrates.
• Chemical Stability: Its superior chemical inertness makes it resistant to corrosion in complex semiconductor processes.

2. Zirconia (ZrO₂) Coating:

• Outstanding High-Temperature Performance: With a melting point as high as 2700°C, zirconia ensures stability in extreme high-temperature environments.
• Good Mechanical Strength: Provides additional structural support to reduce damage from thermal shocks.

Both coatings significantly enhance the performance of graphite boats, offering effective protection for critical manufacturing processes.

Typical Application Fields of Thermal Spraying Ceramic Coatings

1. Semiconductor Industry

• Wafer Manufacturing and Chip Packaging: Providing high-temperature and anti-chemical corrosion protection.
• Diffusion Furnaces: Improving thermal treatment stability and extending equipment lifespan.

2. High-Temperature Industries

• Metallurgical Furnaces: Enhancing heat resistance and reducing oxidation effects.
• Ceramic Sintering and Glass Melting Furnaces: Offering structural protection during high-temperature operations.

3. Aerospace

• High-Temperature Component Protection and Repair: Ensuring performance stability in extreme environments.

4. Power Industry

• Protection of Boiler Heat-Absorbing Surfaces and Turbine Blades: Increasing component durability and reducing maintenance requirements.

In these applications, ceramic coating technology not only extends the lifespan of graphite boats but also enhances process reliability and product quality.

Sheng Lei New Materials specializes in the production and manufacturing of plasma spraying electrodes, with extensive experience. We provide high-quality materials, precise dimensions, and excellent performance for electrodes and nozzles used in thermal spraying applications, including those commonly used in ceramic spraying such as the SG-100 spray gun’s anodes and cathodes (e.g., 01083A-720, 03083-129, 02083-730, 01083A-112, 01083A-104, 03083-145, 03083-165, 03083-175). We also offer custom processing for special requirements.

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