Opaque Quartz Perforated Sheets: High-Reflectivity Thermal Radiation Shielding Materials for Semiconductor-Mia

Project Overview

• Client: Korean photovoltaic equipment component manufacturer

• Product: Opaque quartz perforated sheets (for thermal radiation shielding in PECVD furnaces)

• Supplier: Lianyungang Shengfan Quartz Products Co., Ltd.

• Material: High-purity opaque (milky/opalescent) quartz

• Key Properties: Infrared reflectance ≥ 85%, thermal conductivity ≤ 1.4 W/m·℃

• Application: Thermal insulation liners for graphite susceptors in photovoltaic PECVD tube furnaces, thermal radiation shielding layers for diffusion furnaces, protective liners for high-temperature heat-treatment chambers

• Core Processes: Diamond wire saw cutting, CNC precision carving, double-sided lapping, burr-free edge finishing, precision perforation

Client's Original Pain Points

1. Insufficient Thermal Shielding with Transparent Quartz

The client previously used clear transparent quartz plates as radiation shields in their PECVD tube furnaces. Transparent quartz allows substantial infrared transmission, resulting in excessive heat reaching the furnace outer walls. This caused accelerated aging of peripheral O-rings, sensors, and water-cooling lines, requiring maintenance shutdowns every 4–6 weeks—significantly increasing downtime costs.

2. Spliced Structure Leading to Heat Leakage and Mechanical Failure

The former supplier could only produce small-sized opaque quartz plates (maximum 300×200 mm), requiring multiple pieces to be spliced together for large furnace shielding areas. At operating temperatures around 400°C, thermal radiation leakage through splice gaps reached unacceptable levels. Furthermore, inconsistent thermal expansion between spliced sections caused fixture loosening and plate displacement, compromising shielding effectiveness and occasionally resulting in plate fracture.

3. Insufficient Perforation Accuracy Causing Installation Difficulties

Each shielding plate required multiple positioning holes and airflow channels. The previous supplier's conventional drilling methods produced hole-position deviations exceeding ±0.1 mm, with rough hole walls prone to chipping. This forced the client to manually rework each shipment—a time-consuming process that consumed approximately 30 minutes per plate—significantly delaying furnace assembly schedules.

Our Targeted Solutions & Advantages

1. Premium Opaque Quartz Material with Superior Thermal Reflection

We selected high-purity opaque quartz blanks featuring uniformly distributed microbubbles (diameter 10–100 μm, content ≥ 20%), achieving infrared reflectance ≥ 85% across the 2.5–16 μm wavelength range. Thermal conductivity of only 1.4 W/m·℃ substantially outperforms transparent quartz (1.6–1.8 W/m·℃), effectively blocking radiant heat transfer to the furnace outer wall. The material's inherently low thermal expansion coefficient (5.4×10⁻⁷/℃) ensures excellent thermal shock resistance, preventing fracture or delamination during repeated thermal cycling.

2. Large-Format One-Piece Forming Eliminating Splice Gaps

Leveraging our large-format CNC machining centers, we can produce one-piece opaque quartz plates up to 800×600 mm, completely eliminating splice gaps and the associated thermal leakage issues. For the client's various furnace models, we offer full-series one-piece solutions ranging from 200×200 mm to 650×450 mm, ensuring seamless integration with existing equipment designs.

3. Precision Perforation Ensuring Accurate Installation

Utilizing CNC drilling centers equipped with diamond-coated drill bits, we consistently achieve:

• Hole diameter tolerance: ±0.02 mm

• Hole-position accuracy: ±0.03 mm

• Hole wall roughness after polishing: Ra ≤ 0.4 μm

• Burr-free and chip-free hole edges

This precision eliminates the need for manual rework, enabling immediate installation upon receipt.

Cooperation Results & Client Feedback

1. Significant Thermal Shielding Improvement

After three months of continuous operation in PECVD tube furnaces, the opaque quartz perforated sheets achieved a temperature reduction of approximately 45°C at the furnace outer wall surface compared to the previous transparent quartz solution. Peripheral component service life (O-rings, sensors, cooling lines) extended from 4–6 weeks to over 6 months, reducing maintenance frequency by 75%.

2. Assembly Efficiency Dramatically Improved

The one-piece forming design eliminated splicing procedures, while high-precision hole positioning enabled plug-and-play installation. Furnace assembly time per unit was reduced from approximately 2 hours to 45 minutes—a 62% reduction—allowing the client to accelerate production ramp-up schedules.

3. Product Lifespan Exceeded Expectations

Under continuous 400°C operating conditions, the first batch of 800 pieces has maintained service for more than 12 months without fracture, deformation, or surface delamination—achieving a lifespan four times longer than the previous supplier's products.