Why Is Quartz So Important in the Semiconductor Supply Chain?

When people discuss the semiconductor supply chain, they focus on silicon wafers, EUV lithography machines, and chip design software. Yet behind every advanced node chip — from the 3 nm processors in AI accelerators to the power semiconductors in electric vehicles — sits a material that is rarely mentioned but is functionally irreplaceable: high-purity quartz.

Quartz (ultra-pure silicon dioxide, SiO₂) is the invisible backbone of semiconductor manufacturing. It holds the molten silicon from which every wafer is grown, lines the furnaces where transistors are formed, carries wafers through 1,000°C process steps, and shapes the ultraviolet light that prints circuit patterns at nanometer resolution. No other material can simultaneously meet the purity, thermal, chemical, and optical requirements of modern chip fabrication.

At JACAN, we process high-purity quartz for advanced industrial applications, and we see firsthand how the semiconductor industry’s demand for ever-purer, ever-more-precise quartz components drives the entire upstream mineral processing chain. Below is a detailed explanation of why quartz is indispensable.

1. The Unique Properties That Make Quartz Irreplaceable

Quartz’s importance stems from a combination of properties that no other engineering material can match simultaneously:

Ultra-High Purity

Semiconductor-grade quartz reaches 5N to 6N purity (99.999% to 99.9999% SiO₂), with total metallic impurities controlled to < 1–10 ppm and individual alkali metals (Na, K, Li) often below 0.5 ppm. For the most demanding DUV optics, synthetic fused silica achieves total metals < 1 ppm. This level of purity ensures that the quartz itself does not contaminate the silicon wafer or the process environment.

Extreme Thermal Stability

• Softening point: ~1,600°C+
• Continuous use temperature: 1,100–1,200°C (some grades up to 1,300°C)
• Thermal shock resistance: Excellent — quartz can be heated to 1,000°C and plunged into water without cracking.

This makes quartz the only practical material for furnace tubes and crucibles that must withstand the 800–1,500°C temperatures of silicon crystal growth, diffusion, oxidation, and CVD.

Near-Zero Thermal Expansion

Fused quartz has a coefficient of thermal expansion of ~5.5 × 10⁻⁷ /°C — roughly 1/20 that of ordinary glass and 1/10 that of alumina. This means:

• Dimensional stability at process temperatures is precise to sub-micron levels.
• Thermal cycling does not warp or crack large components.
• For lithography optics, this stability is essential for maintaining nanometer-scale imaging accuracy.

Chemical Inertness

Quartz resists virtually all acids (except hydrofluoric acid) and most bases at room temperature. It does not react with dopant gases (BCl₃, PH₃, AsH₃), CVD precursors, or etching chemistries — ensuring that the process chemistry inside a quartz reactor is exactly what the engineer intended, not modified by wall reactions.

Broad Optical Transparency

Unlike ordinary glass, which absorbs ultraviolet light, high-purity fused quartz transmits from the deep ultraviolet (160 nm) through the infrared (3,500 nm), with UV transmittance > 92% in optimized grades. This makes it the only viable material for DUV lithography optics at 248 nm and 193 nm.

Excellent Electrical Insulation

With resistivity around 1 × 10¹⁸ Ω·cm and high dielectric strength, quartz does not interfere with plasma processes or create parasitic electrical paths in sensitive equipment.

No alternative material matches this combination. Alumina (Al₂O₃) is thermally stable but risks aluminum contamination and has higher thermal expansion. Silicon carbide (SiC) is refractory but opaque and difficult to machine into large, complex shapes. Sapphire is transparent but prohibitively expensive and size-limited. Ordinary borosilicate glass cannot withstand the temperatures or purity requirements. Quartz is the only material that checks every box.

2. Application 1: Quartz Crucibles — The Birthplace of Every Silicon Wafer

The single most important use of quartz in semiconductors is the quartz crucible used in the Czochralski (CZ) process to grow single-crystal silicon ingots.

How It Works

In CZ growth:

1. Polycrystalline silicon (electronic-grade polysilicon, 11N+ purity) is loaded into a quartz crucible.
2. The crucible is heated to ~1,450°C in an argon atmosphere, melting the silicon.
3. A seed crystal is dipped into the melt and slowly pulled upward while rotating, growing a cylindrical single-crystal ingot up to 300–450 mm in diameter and 2–3 meters long.
4. The ingot is sliced into wafers, which become the substrate for every chip.

Why Quartz Is Essential

• The crucible must hold molten silicon at 1,450°C for 48–96 hours per ingot pull without deforming, reacting, or shedding particles.
• Its purity directly determines the ingot’s impurity content. Alkali metals (Na, K, Li) and transition metals (Fe, Cu, Cr) diffuse from the crucible wall into the molten silicon, degrading minority carrier lifetime and causing device defects.
• The inner surface of high-end crucibles is often lined with synthetic silica (total metals < 0.1 ppm) to minimize contamination at the melt interface.

Purity Requirements

• Mainstream semiconductor (≥ 28 nm): 5N (99.999%) natural quartz, total metals ≤ 10 ppm.
• Advanced nodes (≤ 14 nm / 7 nm / 5 nm): 5N+ to 6N, with synthetic silica inner layers.
• Photovoltaic (solar): 4N8 (99.998%) — lower purity, but still quartz.

Crucibles are consumables — each one is used for a single ingot pull and then discarded (or recycled). A 300 mm wafer fab pulling 24/7 consumes hundreds of crucibles per year. This makes quartz crucibles the largest single segment of the semiconductor quartz market.

3. Application 2: Furnace Tubes, Boats, and Wafer Carriers

After the wafer is sliced, it enters the fab, where quartz components dominate the high-temperature processing tools.

Diffusion and Oxidation Furnace Tubes

In horizontal and vertical furnaces, wafers are heated to 800–1,200°C to:

• Grow thermal SiO₂ (gate oxide, field oxide)
• Diffuse dopants (boron, phosphorus, arsenic) into the silicon
• Perform annealing steps

The entire batch of wafers (50–200 wafers per load) sits inside a quartz process tube — a cylinder 200–400 mm in diameter and 1–3 meters long. The tube must:

• Withstand repeated thermal cycling from room temperature to 1,100°C.
• Not contaminate wafers with metal ions.
• Allow uniform gas flow and temperature distribution.

Quartz Boats and Cantilevers

Inside the furnace tube, wafers are held in quartz boats (also called wafer carriers or baskets) — precision-machined structures with slots that hold each wafer vertically and evenly spaced. These boats are mounted on a quartz cantilever or paddle that inserts and withdraws the wafer batch from the hot zone.

Requirements are extreme:

• Slot positioning tolerance: ± 0.1 mm to ensure uniform heating and gas exposure.
• Surface finish: < 1 μm Ra to prevent particle generation.
• The boat must support 50–200 wafers (each ~100–200 g) at 1,100°C without sagging.

Why Quartz

At these temperatures, any other material — stainless steel, alumina, even silicon carbide — would either contaminate the wafers, outgas, or fail thermally. Quartz is the only material that combines the required purity, thermal stability, and machinability into these large, complex structures.

4. Application 3: CVD and Etch Chamber Components

Beyond furnaces, quartz is used extensively in chemical vapor deposition (CVD) and etching tools:

CVD Liners and Showerheads

• Quartz liners protect the chamber walls in LPCVD and PECVD reactors, preventing deposition on metal walls and enabling easy cleaning.
• Quartz showerheads distribute precursor gases uniformly across the wafer surface — a critical function for film thickness uniformity, which must be controlled to < 1% variation across a 300 mm wafer.

Etch Chamber Parts

In both wet and plasma etching:

• Quartz rings and electrodes confine the plasma and protect chamber hardware.
• Quartz’s resistance to fluorine-based plasmas (used in silicon etching) makes it durable, though it is slowly etched itself — making it a consumable that requires periodic replacement.

Rapid Thermal Processing (RTP)

In RTP tools, wafers are heated to 1,000–1,100°C in seconds using lamp heating. Quartz plates and windows transmit the infrared lamp energy to the wafer while maintaining the process atmosphere. Quartz’s IR transparency and thermal shock resistance are essential here.

5. Application 4: DUV Lithography Optics — The Purest Light

Perhaps the most technologically demanding use of quartz is in deep ultraviolet (DUV) photolithography — the process that prints circuit patterns onto wafers.

The Requirement

DUV scanners (using 248 nm KrF or 193 nm ArF excimer lasers) project the circuit pattern through a complex lens system onto the wafer. The optical elements in these systems — lenses, prisms, windows — must:

• Transmit DUV light with > 92% efficiency (ordinary glass absorbs DUV completely).
• Have zero internal defects (bubbles, inclusions, striae) that would scatter light and blur the image.
• Maintain dimensional stability under intense laser illumination and thermal cycling.
• Achieve surface figure accuracy of < 1 nm (sub-wavelength precision).

Why Synthetic Fused Silica

Only synthetic fused silica — produced by flame hydrolysis of high-purity SiCl₄ — meets these requirements. It achieves:

• 6N+ purity (99.9999%+ SiO₂)
• Total metallic impurities < 1 ppm
• OH content precisely controlled (low-OH for IR, high-OH for UV transmission)
• Ultra-low birefringence and homogeneity

A single DUV scanner contains 20–30 large optical elements, many made of synthetic fused silica. The cost of these optics is a significant fraction of the scanner’s $100+ million price tag. For EUV lithography (13.5 nm), the optics are multilayer-coated mirrors rather than transmissive lenses, but quartz still plays roles in illumination optics and metrology systems.

6. Other Critical Applications

Quartz Fiber Cloth (Q-Cloth)

Quartz fiber fabric is used as high-temperature insulation in semiconductor furnace equipment and as a reinforcement in composite materials for chamber components. It withstands continuous use at 1,000°C+ and has extremely low outgassing.

Quartz Windows and Viewports

Every process chamber needs a window for optical pyrometry (temperature measurement), endpoint detection, or visual inspection. Quartz windows transmit the required wavelengths while maintaining vacuum/pressure integrity.

Quartz Flanges, Fittings, and Custom Parts

From gas distribution manifolds to probe tubes to wafer handling end-effectors, quartz is machined into thousands of custom components that fill specific niches in semiconductor tools where purity and chemical resistance are non-negotiable.

7. The Purity Escalation: Why Each Node Demands More

The semiconductor industry’s progress follows Moore’s Law, and quartz purity requirements escalate alongside it:

Each additional “nine” of purity requires exponentially more processing — more aggressive acid leaching, more careful ore selection, cleaner handling environments, and synthetic rather than natural raw materials. The cost rises accordingly, but fabs have no choice: a single trace metal contaminant can cause a killer defect that ruins an entire wafer’s worth of $10,000 chips.

8. Supply Chain Vulnerability: Why Quartz Is a Strategic Material

The semiconductor industry’s dependence on quartz creates a significant supply chain risk:

Resource Concentration

High-purity natural quartz sand suitable for semiconductor use is found in only a handful of deposits worldwide. The most famous is the Spruce Pine district in North Carolina, USA, which has historically supplied the majority of the world’s semiconductor-grade quartz. Other deposits in Australia, Norway, Canada, and China are being developed, but meeting the strictest 5N+ specifications remains challenging.

Processing Bottleneck

Even with good ore, achieving 5N+ purity requires specialized processing: high-intensity magnetic separation, froth flotation, hot acid leaching (HF, HCl), thermal shock processing, and contamination-free grinding and classification. Only a limited number of companies globally can produce semiconductor-grade quartz sand at scale.

Synthetic Quartz Cost

Synthetic fused silica (for DUV optics and crucible inner layers) is produced by flame hydrolysis of SiCl₄, an energy-intensive process that costs 2–5× more than natural quartz per kilogram. As purity demands rise, the share of synthetic quartz in the supply mix increases, driving up costs.

Geopolitical Risk

Because high-purity quartz is concentrated in a few countries and processed by an even smaller number of companies, it is considered a critical mineral by governments in the US, EU, Japan, and China. Export restrictions, trade disputes, or supply disruptions could directly impact global semiconductor manufacturing capacity.

9. Market Scale and Growth

• The global semiconductor quartz materials market was approximately $4.9 billion in 2026 and is growing rapidly, driven by AI chip demand and advanced node expansion.
• Microelectronics accounts for ~35% of the high-purity quartz sand market (the largest single segment).
• The broader semiconductor market is projected at $975.5 billion in 2026 (WSTS), growing 26% year-over-year — every dollar of chip revenue requires quartz in the manufacturing chain.
• AI accelerators (GPUs, TPUs) are manufactured at the most advanced nodes (3–5 nm), which demand the highest-purity quartz components, amplifying both volume and value per unit.

10. The JACAN Perspective

At JACAN, our role in this supply chain is at the upstream processing stage:

• High-purity quartz grinding and classification: We process crystalline quartz into precision-sized powders and sands using all-ceramic media and linings, ensuring that no metallic contamination is introduced during size reduction — a critical requirement for semiconductor-grade material.
• Contamination-free processing: Our systems are designed for materials where even ppm-level iron pickup is unacceptable, using alumina, zirconia, or high-purity quartz contact surfaces throughout.
• Precise particle size control: For quartz sand used in crucible manufacturing and fused silica production, consistent PSD (D50, D97, top size) directly affects melting behavior, bubble formation, and final product homogeneity.
• Quality verification: Every batch is tested for particle size, impurity content (ICP-MS), and moisture before release.

As the semiconductor industry continues its drive toward smaller nodes and higher purity, the upstream processing of quartz — the step that turns raw mineral into a material pure enough to hold molten silicon or transmit DUV light — becomes ever more critical.

Quartz is indispensable in the semiconductor supply chain because it is the only material that simultaneously delivers:

1. 5N–6N purity to avoid contaminating silicon wafers.
2. 1,600°C thermal stability for crystal growth and high-temperature processing.
3. Near-zero thermal expansion for dimensional precision at process temperatures.
4. Chemical inertness to survive aggressive process chemistries.
5. DUV optical transparency for lithography.
6. Machinability into large, complex, precision components.

From the crucible that grows the silicon ingot, to the furnace tube that forms the transistors, to the lenses that print the circuit pattern, to the hundreds of small components in every process tool — quartz is present at nearly every step of chip manufacturing. It is a consumable, a structural material, an optical material, and a process enabler, all in one.

Without high-purity quartz, modern semiconductor manufacturing as we know it would not be possible. And as chips become smaller, faster, and more ubiquitous — especially in the AI era — the demand for ever-purer, ever-more-precise quartz will only intensify.