Quartz Wafer Quartz Wafers 2", 3", 4", 6", 8", 12" SiO₂
Semiconductor Optical
Introduction of Quartz Wafer
Quartz wafers are made from crystalline silicon dioxide (SiO₂). The
unique properties of quartz make it an essential material in
various high-tech industries.
Quartz wafers exhibit excellent characteristics such as high
thermal resistance, superior light transmission at specific
wavelengths, chemical inertness, and a low coefficient of thermal
expansion. These features make them highly suitable for
applications that require stability under extreme temperatures,
resistance to harsh chemicals, and transparency in specific
spectral ranges.
In industries such as semiconductor manufacturing, optics, and MEMS
(Micro-Electro-Mechanical Systems), quartz wafers are widely used
due to their ability to withstand high temperatures without
deformation or degradation. They serve as substrates for thin-film
deposition, microstructure etching, or the fabrication of precision
components that demand high dimensional accuracy and thermal
stability.
Manufacturing Principle of Quartz Wafer
Crystal Growth
Quartz boules are grown using natural or synthetic seed crystals
through hydrothermal or flame fusion (Verneuil) methods.
Ingot Slicing
Cylindrical ingots are sliced into wafers using diamond wire saws,
ensuring thickness uniformity and minimal kerf loss.
Lapping and Polishing
Wafers are lapped, etched, and then polished to achieve a
mirror-smooth finish with low surface roughness (Ra < 1 nm for
optical-grade wafers).
Cleaning & Inspection
Ultrasonic or RCA cleaning removes particulates and metallic
contaminants. Each wafer undergoes dimensional and surface flatness
inspection.
Quartz Wafer Specifications
| Quartz Type | 4 | 6 | 8 | 12 |
|---|
| Size | | | | |
| Diameter (inch) | 4 | 6 | 8 | 12 |
| Thickness (mm) | 0.05–2 | 0.25–5 | 0.3–5 | 0.4–5 |
| Diameter Tolerance (inch) | ±0.1 | ±0.1 | ±0.1 | ±0.1 |
| Thickness Tolerance (mm) | Customizable | Customizable | Customizable | Customizable |
| Optical Properties | | | | |
| Refractive Index @365 nm | 1.474698 | 1.474698 | 1.474698 | 1.474698 |
| Refractive Index @546.1 nm | 1.460243 | 1.460243 | 1.460243 | 1.460243 |
| Refractive Index @1014 nm | 1.450423 | 1.450423 | 1.450423 | 1.450423 |
| Internal Transmittance (1250–1650 nm) | >99.9% | >99.9% | >99.9% | >99.9% |
| Total Transmittance (1250–1650 nm) | >92% | >92% | >92% | >92% |
| Machining Quality | | | | |
| TTV (Total Thickness Variation, µm) | <3 | <3 | <3 | <3 |
| Flatness (µm) | ≤15 | ≤15 | ≤15 | ≤15 |
| Surface Roughness (nm) | ≤1 | ≤1 | ≤1 | ≤1 |
| Bow (µm) | <5 | <5 | <5 | <5 |
| Physical Properties | | | | |
| Density (g/cm³) | 2.20 | 2.20 | 2.20 | 2.20 |
| Young's Modulus (GPa) | 74.20 | 74.20 | 74.20 | 74.20 |
| Mohs Hardness | 6–7 | 6–7 | 6–7 | 6–7 |
| Shear Modulus (GPa) | 31.22 | 31.22 | 31.22 | 31.22 |
| Poisson's Ratio | 0.17 | 0.17 | 0.17 | 0.17 |
| Compressive Strength (GPa) | 1.13 | 1.13 | 1.13 | 1.13 |
| Tensile Strength (MPa) | 49 | 49 | 49 | 49 |
| Dielectric Constant (1 MHz) | 3.75 | 3.75 | 3.75 | 3.75 |
| Thermal Properties | | | | |
| Strain Point (10¹⁴.⁵ Pa·s) | 1000°C | 1000°C | 1000°C | 1000°C |
| Annealing Point (10¹³ Pa·s) | 1160°C | 1160°C | 1160°C | 1160°C |
| Softening Point (10⁷.⁶ Pa·s) | 1620°C | 1620°C | 1620°C | 1620°C |
Frequently asked questions about quartz wafers
1. What is a quartz wafer?
A quartz wafer is a thin, flat disc made from crystalline silicon
dioxide (SiO₂), typically manufactured in standard semiconductor
sizes (e.g., 2", 3", 4", 6", 8", or 12"). Known for its high
purity, thermal stability, and optical transparency, a quartz wafer
is used as a substrate or carrier in various high-precision
applications such as semiconductor fabrication, MEMS devices,
optical systems, and vacuum processes.
2. What is the difference between quartz and silica gel?
Quartz is a crystalline solid form of silicon dioxide (SiO₂), while
silica gel is an amorphous and porous form of SiO₂, commonly used
as a desiccant to absorb moisture.
Quartz is hard, transparent, and used in electronic, optical, and
industrial applications.
Silica gel appears as small beads or granules and is primarily used for
humidity control in packaging, electronics, and storage.
3. What are quartz crystals used for?
Quartz crystals are widely used in electronics and optics due to
their piezoelectric properties (they generate an electric charge
under mechanical stress). Common applications include:
Oscillators and frequency control (e.g., quartz watches, clocks, microcontrollers)
Optical components (e.g., lenses, waveplates, windows)
Resonators and filters in RF and communication devices
Sensors for pressure, acceleration, or force
Semiconductor fabrication as substrates or process windows
4. Why is quartz used in microchips?
Quartz is used in microchip-related applications because it offers:
Thermal stability during high-temperature processes like diffusion and annealing
Electrical insulation due to its dielectric properties
Chemical resistance to acids and solvents used in semiconductor fabrication
Dimensional precision and low thermal expansion for reliable lithography alignment
While quartz itself isn't used as the active semiconductor material
(like silicon), it plays a vital supporting role in the fabrication
environment—especially in furnaces, chambers, and photomask
substrates.
