In modern semiconductor manufacturing, material science plays a role as critical as the equipment itself. Among all functional materials, high-purity quartz (SiO₂) stands out as an indispensable backbone across nearly every stage of chip fabrication—from single-crystal silicon growth to advanced wafer processing. Thanks to its exceptional purity, high thermal resistance, chemical inertness, and optical transparency, quartz components are essential for maintaining the ultra-clean and highly controlled environments required in semiconductor fabs.
1. Fundamental Properties of Quartz and Process Compatibility
The widespread use of quartz in semiconductor equipment is rooted in its unique physical and chemical characteristics:
- Ultra-high purity (4N8 and above): Metallic impurities can be controlled down to ppm or even ppb levels
- Excellent thermal stability: Melting point above 1700°C, with long-term operation exceeding 1100–1200°C
- Low coefficient of thermal expansion: Minimizes thermal stress and deformation
- Outstanding chemical resistance: Stable against most acids and gases except hydrofluoric acid (HF)
- High optical transparency: განსაკუთრებით effective in ultraviolet (UV) wavelengths
These properties allow quartz to function not only as a structural material but also as an integral part of the process environment itself.
2. Silicon Crystal Growth: The Foundational Role of Quartz Crucibles
In the Czochralski (CZ) process, quartz crucibles are indispensable consumables used to melt polysilicon and grow single-crystal silicon ingots.
Key Technical Requirements:
| Parameter | Typical Specification |
|---|---|
| Purity | ≥ 99.998% (4N8) |
| Operating Temperature | 1400–1600°C |
| Oxygen Control | Critical for defect engineering |
| Dimensional Stability | Prevents deformation during growth |
Quartz crucibles influence oxygen incorporation into the silicon melt, which directly affects crystal defects and electrical properties. Therefore, both raw material quality and manufacturing processes (e.g., arc melting, rotational forming) are tightly controlled.
3. High-Temperature Processing: Quartz Tubes and Boats
Quartz components are extensively used in diffusion, oxidation, and chemical vapor deposition (CVD) processes.
3.1 Quartz Tubes
Quartz tubes serve as high-temperature reaction chambers:
- Continuous operation above 1100°C
- Extremely low metal contamination (≤1 ppm)
- High resistance to thermal shock and deformation
3.2 Quartz Boats
Quartz boats are used to carry multiple wafers during batch processing:
- Compatible with 4-inch to 12-inch wafers
- Available in vertical and horizontal configurations
- Require high mechanical strength and ultra-low particle generation
Together, these components form the backbone of thermal processing systems in wafer fabs, directly impacting yield and process uniformity.
4. Etching and Deposition: Quartz Structural Components
In plasma etching and thin-film deposition processes (such as PVD, CVD, and ALD), quartz parts act as critical structural and protective elements.
Typical Quartz Components:
- Quartz rings and focus rings: Maintain plasma uniformity and protect chamber walls
- Flansche aus Quarz: Ensure vacuum sealing and system integrity
- Quartz injectors: Precisely deliver process gases or liquids
These components must withstand plasma exposure, reactive gases, and high-energy ion bombardment, while maintaining dimensional precision and cleanliness.
5. Cleaning Processes: Quartz Tanks and Carriers
Wet cleaning is a vital step in semiconductor fabrication, involving chemicals such as HF, H₂SO₄, and NH₄OH.
Quartz Applications in Cleaning:
- Quartz cleaning tanks: مقاومة strong acids and high temperatures
- Quartz baskets (carriers): Hold wafers during chemical cleaning
- Quartz liquid collection bottles: Collect and store residual chemicals without contamination
Quartz ensures that no additional impurities are introduced during cleaning, which is critical for advanced nodes where contamination control is extremely stringent.
6. Advanced Applications: Quartz Bell Jars and Photolithography
6.1 Quartz Bell Jars
Quartz bell jars are widely used in:
- Polysilicon production reactors
- Epitaxial growth systems
They provide a controlled reaction environment and enable uniform thermal radiation transmission, which is essential for process stability and film uniformity.
6.2 Photolithography and Optical Components
Quartz is also used in optical applications due to its high UV transparency:
- Quartz photomasks: Serve as “master templates” for pattern transfer
- Quartz windows: Enable precise UV exposure in lithography systems
These components are essential for achieving high-resolution patterning in advanced semiconductor nodes.
7. Process Monitoring: Quartz Crystal Sensors
In thin-film deposition processes, quartz crystal microbalance (QCM) sensors are used to monitor film thickness in real time. These sensors rely on the frequency change of a vibrating quartz crystal to measure mass deposition with high precision, ensuring uniformity and process control.
8. 2026 Trends: Higher Purity, Larger Sizes, and Localization
As semiconductor technology continues to evolve, quartz components are facing increasingly stringent requirements:
8.1 Higher Purity Standards
Advanced nodes demand impurity levels below ppb, pushing the development of synthetic quartz over natural quartz.
8.2 Larger Dimensions
With the transition toward larger wafers (300 mm and beyond), quartz components must scale accordingly while maintaining structural integrity.
8.3 Enhanced Durability
Longer equipment lifecycles and harsher process conditions require improved resistance to plasma erosion and thermal cycling.
8.4 Localization and Supply Chain Security
Driven by global supply chain dynamics, domestic manufacturing of high-end quartz components is becoming a strategic priority, particularly in emerging semiconductor markets.
Schlussfolgerung
Quartz components are far more than auxiliary materials in semiconductor manufacturing—they are foundational enablers of process stability, purity, and precision. From crystal growth and thermal processing to etching, cleaning, and photolithography, quartz plays a critical role at every stage.
As the semiconductor industry advances into more demanding technological nodes in 2026 and beyond, the requirements for quartz materials—in purity, performance, and precision—will continue to rise. This not only presents technical challenges but also creates opportunities for innovation and localization in the global semiconductor supply chain.
