What are silicon carbide ceramics?

In today’s booming semiconductor industry, semiconductor ceramic components have secured a vital position in semiconductor equipment due to their unique properties. Let’s delve into these critical components.

Ⅰ. What Materials Are Used in Semiconductor Ceramic Components?

(1) ‌Alumina Ceramics (Al₂O₃)‌

Alumina ceramics are the "workhorse" for manufacturing ceramic components. They exhibit excellent mechanical properties, ultra-high melting points and hardness, corrosion resistance, strong chemical stability, high resistivity, and superior electrical insulation. They are commonly used to fabricate polishing plates, vacuum chucks, ceramic arms, and similar parts.

(2) ‌Aluminum Nitride Ceramics (AlN)‌

Aluminum nitride ceramics feature high thermal conductivity, a thermal expansion coefficient matching that of silicon, and low dielectric constant and loss. With advantages such as high melting point, hardness, thermal conductivity, and insulation, they are primarily used in heat-dissipating substrates, ceramic nozzles, and electrostatic chucks.

(3) ‌Yttria Ceramics (Y₂O₃)‌

Yttria ceramics boast a high melting point, excellent chemical and photochemical stability, low phonon energy, high thermal conductivity, and good transparency. In the semiconductor industry, they are often combined with alumina ceramics—for example, yttria coatings are applied to alumina ceramics to produce ceramic windows.

(4) ‌Silicon Nitride Ceramics (Si₃N₄)‌

Silicon nitride ceramics are characterized by a high melting point, exceptional hardness, chemical stability, low thermal expansion coefficient, high thermal conductivity, and strong thermal shock resistance. They maintain outstanding impact resistance and strength below 1200°C, making them ideal for ceramic substrates, load-bearing hooks, positioning pins, and ceramic tubes.

(5) ‌Silicon Carbide Ceramics (SiC)‌

Silicon carbide ceramics, resembling diamond in properties, are lightweight, ultra-hard, and high-strength materials. With exceptional comprehensive performance, wear resistance, and corrosion resistance, they are widely used in valve seats, sliding bearings, burners, nozzles, and heat exchangers.

(6) ‌Zirconia Ceramics (ZrO₂)‌

Zirconia ceramics offer high mechanical strength, heat resistance, acid/alkali resistance, and excellent insulation. Based on zirconia content, they are categorized into:

● Precision ceramics‌ (content exceeding 99.9%, used for integrated circuit substrates and high-frequency insulating materials).

● Ordinary ceramics‌ (for general-purpose ceramic products).

Ⅱ. Structural Characteristics of Semiconductor Ceramic Components

(1) ‌Dense Ceramics‌

Dense ceramics are widely used in the semiconductor industry. They achieve densification by minimizing pores and are prepared via methods such as reaction sintering, pressureless sintering, liquid-phase sintering, hot pressing, and hot isostatic pressing.

(2) ‌Porous Ceramics‌

In contrast to dense ceramics, porous ceramics contain a controlled volume of voids. They are classified by pore size into microporous, mesoporous, and macroporous ceramics. With low bulk density, lightweight structure, large specific surface area, effective filtration/thermal insulation/acoustic damping properties, and stable chemical/physical performance, they are used to manufacture various components in semiconductor equipment.

Ⅲ. How are semiconductor ceramics formed?

There are various molding methods for ceramic products, and the commonly used molding methods for semiconductor ceramic parts are as follows:

Ⅳ. Semiconductor Ceramic Component Sintering Methods‌

1.‌Solid-State Sintering‌

Achieves densification through mass transport without liquid phases, suitable for high-purity ceramics‌.

2.‌Liquid-Phase Sintering‌

Utilizes transient liquid phases to enhance densification but risks grain boundary glass phases that degrade high-temperature performance‌.

3.‌Self-Propagating High-Temperature Synthesis (SHS)‌

Relies on exothermic reactions for rapid synthesis, particularly effective for non-stoichiometric compounds‌.

4.‌Microwave Sintering‌

Enables uniform heating and rapid processing, improving mechanical properties in submicron-scale ceramics‌.

5.‌Spark Plasma Sintering (SPS)‌

Combines pulsed electric currents and pressure for ultrafast densification, ideal for high-performance materials‌.

6.‌Flash Sintering‌

Applies electric fields to achieve low-temperature densification with suppressed grain growth‌.

7.‌Cold Sintering‌

Uses transient solvents and pressure for low-temperature consolidation, critical for temperature-sensitive materials‌.

8.‌Oscillatory Pressure Sintering‌

Enhances densification and interfacial strength through dynamic pressure, reducing residual porosity‌