What Are the Small Holes in a CFC Top Plate Used For?

Written by Lucy Zhang@Semicera.

In advanced semiconductor manufacturing processes for LED epitaxy, GaN power devices, and SiC single-crystal growth, the uniformity of high-temperature thermal fields, dimensional stability, and cleanliness directly determine wafer yield and batch consistency. As the core top component of thermal systems, traditional isostatic graphite top plates are prone to issues such as warping deformation, powder shedding, carbon precipitation, and thermal gradient deviation under prolonged exposure to high temperatures, vacuum conditions, and thermal cycling cycles—leading to uneven epitaxial thickness, wafer contamination, and frequent equipment downtime for maintenance.

In contrast, C/C composite (CFC) top plates have completely replaced conventional graphite counterparts due to their superior properties: ultra-low thermal expansion, resistance to high-temperature creep, exceptional cleanliness, and outstanding thermal shock stability, making them the standard upgrade component for MOCVD epitaxial furnaces, SiC-PVT crystal growth furnaces, and high-temperature annealing furnaces. This article elaborates on the core manufacturing technologies for high-end semiconductor-grade CFC top plates from four perspectives: material design, fabrication processes, precision control, and operational compatibility.

In industries such as semiconductors, photovoltaics, silicon carbide crystal growth, and high-temperature sintering, CFC (Carbon Fiber Composite) top plates are critical thermal field components. Many customers often wonder why these plates contain multiple holes of different sizes.

In fact, these holes are not merely machining features; they are an essential part of thermal field engineering.

Improving Temperature Uniformity

In high-temperature processes, temperature uniformity directly affects product quality.

For example:

• Crystal quality in SiC crystal growth
• Density consistency in sintered products
• Film uniformity in semiconductor processing

By adjusting hole diameters and their distribution, engineers can regulate local thermal radiation intensity. Larger holes increase local heat dissipation, while smaller holes help retain heat.

Therefore, hole patterns serve as an effective method of temperature field control.

Relieving Thermal Stress

CFC top plates often operate in environments ranging from 1600°C to over 2500°C. During repeated heating and cooling cycles, materials undergo thermal expansion and contraction.

If the structure is completely solid, thermal stress can continuously accumulate.

This may result in:

• Warping
• Micro-cracks
• Premature failure

Properly designed holes reduce stress concentration and improve structural stability.

Optimizing Gas Flow Distribution

Many high-temperature processes require continuous gas flow.

Examples include:

• Argon (Ar)
• Nitrogen (N₂)
• Hydrogen (H₂)
• Process gases

The holes help distribute gases more evenly throughout the thermal field. This minimizes stagnant zones and improves process stability.

Reducing Overall Weight

Large CFC top plates often feature substantial dimensions and thickness. Strategically placed holes reduce material usage while maintaining mechanical strength.

Benefits include:

• Lower weight
• Reduced cost
• Easier installation and maintenance

Why Are the Hole Sizes Different?

Many customers notice that hole diameters vary across different areas of the plate. This is because temperature distribution within a thermal field is inherently non-uniform. Engineers utilize Thermal Simulation, FEA, and CFD to determine the optimal hole size and positioning.

As a result, every hole location serves a specific engineering purpose. The holes in a CFC top plate are far more than simple machining features.

They play important roles in:

1. Thermal field optimization
2. Thermal stress relief
3. Gas flow management
4. Structural lightweighting

A well-designed hole pattern can provide better temperature uniformity, longer service life, and more stable process performance.

For high-temperature thermal field systems, a CFC top plate is not merely a structural component but a key engineering product that reflects advanced thermal field design capabilities.

Semicera’s CFC Top Plate

Semicera quasi-3D C/C composite features high carbon fiber content, manufactured by hot pressing and resin densification process with shorter production cycle.

Advantages:

1. The quasi-three-dimensional high-carbon fiber skeleton combined with hot-press impregnation technology ensures high molding efficiency and short delivery cycles;

2. its low density paired with ultra-high tensile and flexural strength achieves lightweight design while maintaining structural stability;

3. its mechanical properties comprehensively surpass those of isostatic graphite, featuring excellent creep resistance and thermal shock resistance, making it ideal for high-performance high-temperature consumables such as semiconductor thermal field CFC top plates, support discs, and insulation components. 

Choose Semicera

Semicera has been deeply engaged in the high-end thermal field materials of semiconductors for many years, focusing on high-precision manufacturing scenarios such as third-generation semiconductors, high-end LED epitaxy, and SiC single crystal growth. It is a professional supplier. Unlike ordinary processing manufacturers, Semicera is not limited to precision machining. It also masters core underlying technologies such as CFC material structure customization, CVI densification process, PPB-level high-purity purification, and coating modification.

According to different equipment working conditions, process temperatures, and mechanical requirements, it can customize high-matching CFC top plate products specifically Avoid mass production problems such as thermal deformation, powder dropping and impurity contamination from the source of materials.

Relying on a complete quality control system and GDMS full-batch inspection standards, Semicera strictly controls the density, flatness, thermal stability and cleanliness of each CFC top plate. The batch consistency is excellent and it can be adapted to many mainstream semiconductor devices.

With stable product performance, an extremely long service life, and an ultimate yield empowerment capability, Semicera has become a long-term reliable supply chain partner for many leading semiconductor and optoelectronic enterprises at home and abroad. It helps customers reduce costs and increase efficiency and enhance the core competitiveness of their products with advanced material technology.