Fused Silica / Quartz Substrates
High-purity fused silica and quartz glass wafer substrates for UV lithography, optics, MEMS, and photonics. Available in 100mm to 300mm diameters with exceptional UV transmission, near-zero thermal expansion, and surface roughness below 0.5nm RMS.
High-Purity Fused Silica & Quartz Glass Substrates
Fused silica and quartz glass are amorphous silicon dioxide (SiO₂) materials that combine exceptional optical transparency from the deep-ultraviolet (185nm) through the near-infrared (3,500nm) with near-zero thermal expansion (CTE 0.55 × 10⁻⁶/K), outstanding chemical resistance, and electrical insulation properties. These attributes make fused silica the substrate of choice for UV lithography photomasks, excimer laser optics, precision optical windows, and bio-MEMS devices where polymer or borosilicate alternatives cannot meet the required performance specifications.
The global fused silica wafer market has grown steadily, driven by the relentless scaling of semiconductor lithography to 193nm immersion and EUV wavelengths, the expansion of fiber optic communication networks, and the increasing use of microfluidic lab-on-chip devices in point-of-care diagnostics. At advanced photomask nodes (sub-7nm logic), fused silica substrates must maintain transmission uniformity within ±0.1% across the entire 152mm × 152mm mask blank area — a specification that demands extraordinary control of bulk homogeneity, bubble content, and birefringence.
At GINECHIP, we supply UV-grade (JGS1), IR-grade (JGS3), and synthetic fused silica wafer substrates across all standard diameters from 100mm to 300mm. Every lot includes a full Certificate of Analysis (CoA) documenting transmission spectra, surface roughness, TTV, bow, warp, particle counts, hydroxyl content, and trace impurity levels. Premium-grade substrates with surface roughness below 0.3nm RMS, photomask-grade birefringence (≤ 2 nm/cm), and custom thin-wafer dimensions (down to 100μm thickness) are available on request.
UV-Grade vs Standard vs Synthetic: Material Grade Comparison
Not all fused silica is created equal. The manufacturing route — flame hydrolysis of synthetic SiCl₄, electrothermal fusion of natural quartz, or plasma-assisted deposition — determines the material's optical absorption edge, hydroxyl content, metallic impurities, and laser damage threshold. Understanding these grades is critical for matching the substrate to the application.
UV-Grade (JGS1)
Flame-hydrolysis synthetic SiO₂ — highest UV throughput
Ultra-high transmission from deep-UV (185nm) through near-IR (2,500nm). Produced from high-purity synthetic precursor (SiCl₄) via flame hydrolysis, yielding negligible metallic impurities (< 1 ppm total) and OH content optimized for UV transparency. Essential for 193nm and 248nm photomask substrates, UV beam-splitters, and excimer laser optics.
IR-Grade (JGS3)
Electrothermal fusion from natural quartz — low OH for IR
Optimized for infrared transmission from 1μm to 3.5μm with minimal OH absorption bands. Produced from natural quartz powder via electrothermal fusion, resulting in low hydroxyl content (< 10 ppm) for excellent mid-IR performance. Cost-effective for IR windows, thermal imaging optics, and semiconductor process chambers.
Synthetic Fused Silica
Highest purity via direct SiCl₄ hydrolysis — DUV laser-grade
The purest commercially available fused silica — manufactured from synthetic silicon tetrachloride (SiCl₄) via direct or indirect flame hydrolysis. Total metallic impurities below 0.1 ppm, extremely low bulk absorption (＜ 0.1%/cm at 193nm), and exceptional laser damage threshold (＞ 20 J/cm² at 355nm, 10ns). The gold standard for deep-UV and excimer laser applications requiring near-zero absorption and highest durability.
Optical Properties & Transmission Characteristics
The defining advantage of fused silica over other glass substrates is its extraordinary broadband transmission. The table below summarizes key optical performance metrics across the wavelength range relevant for semiconductor, photonics, and precision optics applications.
Deep-UV (185–250nm)
Transmission > 90% at 185nm for UV-grade; > 99.7%/cm at 193nm for synthetic grade. Low solarization (＜ 0.5% transmission loss after 10⁶ pulses at 193nm, 10 mJ/cm²). Critical for ArF immersion lithography masks.
UV-Visible (250–800nm)
Near-flat transmission exceeding 92% throughout the visible spectrum. Refractive index homogeneity (Δn) ＜ 3 × 10⁻⁶ over 150mm diameter for photomask-grade material. Excellent for i-line (365nm) and broadband imaging.
Near-IR (800–3,500nm)
Minimal absorption bands in IR-grade material with OH content below 10 ppm. Transmission > 85% at 2.7μm water band; excellent for thermal imaging windows and fiber optic component carriers operating in the telecom O- through L-bands.
Processing Technologies for Fused Silica Wafers
Fused silica presents unique processing challenges compared to single-crystal silicon or borosilicate glasses. Its amorphous structure, high softening point (~1,600°C), and chemical inertness require specialized fabrication techniques to achieve the dimensional tolerances and surface quality demanded by photonics and semiconductor applications.
Chemical-Mechanical Polishing (CMP) employing colloidal silica slurry on polyurethane pads is the industry standard for achieving sub-nanometer surface roughness. Multi-step polishing sequences — coarse lapping → fine lapping → CMP rough polish → CMP fine polish — progressively reduce subsurface damage (SSD) while achieving the RMS ＜ 0.5nm finish required for photomask blanks and direct-bonded assemblies.
Dicing and edge grinding of fused silica requires diamond tooling optimized for brittle, amorphous materials. The absence of crystalline cleavage planes — while eliminating orientation-dependent chipping — demands precise feed-rate control and coolant delivery to prevent edge micro-cracking. Edge profiling to SEMI standards (round, bevel, or bullnose) is available with surface quality meeting S/D 40/20 per MIL-PRF-13830B.
Thin-wafer processing down to 100μm thickness is achieved through back-grinding followed by stress-relief etching in buffered HF solutions. Temporary bonding to carrier substrates (silicon or glass) enables safe handling of ultra-thin fused silica wafers through subsequent lithography, deposition, and etch steps in MEMS and microfluidics fabrication flows.
Photomask & Lithography Applications
Fused silica photomask blanks represent the single most demanding application for this material. At the 193nm ArF lithography node — which remains the workhorse for sub-7nm logic manufacturing through multi-patterning — the mask substrate must simultaneously deliver transmission > 99.7%/cm, birefringence ≤ 2nm/cm, thermal expansion below 550 ppb/K, and flatness (TIR) below 0.5μm over 152mm × 152mm. GINECHIP supplies photomask-grade fused silica substrates meeting these exacting specifications with full metrology documentation.
Beyond binary photomasks, fused silica substrates are also used for phase-shift masks (PSMs) — where precisely etched trenches in the quartz substrate induce a 180° phase shift to enhance image contrast — and for nanoimprint lithography (NIL) templates where the material's hardness and durability provide extended stamp lifetimes through thousands of imprint cycles.
Technical Specifications
| Parameter | Available Range / Values |
|---|---|
| Material Grade | UV-grade (JGS1), IR-grade (JGS3), Synthetic Fused Silica |
| Diameter | 100mm (4″), 150mm (6″), 200mm (8″), 300mm (12″) |
| Thickness | 200μm–1100μm, custom ±10μm tolerance |
| Surface Roughness | RMS < 0.5nm standard, < 0.3nm premium |
| TTV (Total Thickness Variation) | ≤ 3μm standard, ≤ 1μm premium |
| Bow / Warp | Bow ≤ 20μm, Warp ≤ 25μm |
| Transmission @ 185nm | > 90% UV-grade, > 85% standard |
| Refractive Index | n₅₈₉ = 1.4585 |
| CTE (Coefficient of Thermal Expansion) | 0.55 × 10⁻⁶/K (20–300°C), nearly zero thermal expansion |
| Dielectric Constant | 3.8 at 1 MHz |
| Softening Point | ~1,600°C (synthetic fused silica) |
| Density | 2.20 g/cm³ |
| Surface Quality | S/D 40/20 per MIL-PRF-13830B or better |
| Packaging | Class 100 cleanroom, interleaved, vacuum-sealed cassette or single-wafer shippers |
Applications & Market Segments
UV & DUV Photomasks
Fused silica is the substrate of choice for photomasks at 365nm (i-line), 248nm (KrF), and 193nm (ArF) lithography wavelengths. UV-grade material with transmission > 90% at the exposure wavelength ensures maximum throughput and minimal thermal lensing during high-dose exposures in stepper and scanner tools.
Excimer Laser Optics
Synthetic fused silica with ultra-low absorption at 193nm and 248nm serves as beam-delivery windows, homogenizer plates, and beam-splitter substrates in excimer laser systems for semiconductor annealing and LASIK medical devices. Laser damage thresholds exceeding 20 J/cm² (10ns, 355nm) ensure long service lifetimes.
Bio-MEMS & Microfluidics
Optically transparent, chemically inert, and biocompatible, fused silica wafers are micro-machined into lab-on-chip devices, micro-reactors, and electrophoresis chips. The material’s near-zero autofluorescence and UV transparency enable on-chip fluorescence detection and UV spectroscopy.
Fiber Optic Components
Fused silica substrates serve as alignment carriers, V-groove arrays, and planar lightwave circuit (PLC) platforms for fiber optic communication networks. The thermal expansion match between the substrate and optical fiber (both silica-based) minimizes thermally-induced alignment drift.
Capacitive MEMS Sensors
High electrical resistivity (> 10¹⁷ Ω·cm) and low dielectric constant make fused silica an excellent structural material for capacitive MEMS accelerometers, gyroscopes, and pressure sensors where parasitic capacitance and electrical leakage must be minimized.
Precision Optics & Windows
From telescope corrector plates to vacuum chamber viewports, fused silica combines near-zero thermal expansion with outstanding transmission uniformity. Custom coatings (AR, HR, beamsplitter) can be applied to meet specific spectral requirements from 185nm to 3,500nm.
Metrology & Quality Assurance
Every fused silica substrate lot undergoes a comprehensive multi-technique metrology protocol at ISO 9001:2015 certified facilities. Optical properties are measured from deep-UV through IR, surface and dimensional characteristics are verified by interferometry and AFM, and a full Certificate of Analysis (CoA) accompanies each shipment.
Need Fused Silica Substrates for Your Application?
Specify your grade (UV-grade / IR-grade / Synthetic), diameter, thickness, surface roughness requirements, and quantity — our substrate specialists will provide a detailed quotation with optical metrology data and lead time within 24 hours.