Semiconductor Quartz Glass for the Fab Environment
Every wafer that leaves a modern fab has passed through quartz glass. FGQuartz has spent twenty years making the tubes, boats, and vessels that support this journey. We manufacture from Lianyungang, China. Our semiconductor quartz glass components ship to fabs in over 40 countries.
Semiconductor Quartz Glass: Why It Matters in the Fab
Extreme Thermal Stability
Quartz resists H₂SO₄, HNO₃, HCl, and H₂O₂. It will not react with standard process gases. This keeps your process chemistry clean and controlled.
Chemical Inertness
Resistant to H₂SO₄, HNO₃, HCl, H₂O₂ · will not react with process gases
Contamination Control
High-purity fused silica introduces no metallic ions into the silicon lattice. This is the core reason fabs depend on semiconductor-grade quartz. Purity protects your yield.
Dimensional Precision
Quartz has near-zero thermal expansion. Your wafer boat slots stay consistent across thousands of furnace cycles. Geometry stays stable under extreme heat.
Optical Transparency
Clear-grade quartz transmits UV through infrared light. This enables in-situ pyrometry inside the furnace. It also supports UV-based processes directly.
Thermal Shock Resistance
Near-zero thermal expansion stops cracks from forming during fast temperature changes. Quartz survives rapid heat ramps that would break other glass types. This is why it outlasts alternatives in high-cycle production environments.
Est. 2005
Lianyungang, Jiangsu, China
Americas · Europe · Asia-Pacific
Full Custom CNC
Prototype to production volume
In-house R&D
Process & material engineering team
Semiconductor Quartz Glass Components
FGQuartz makes the complete range of front-end quartzware. Our products serve thermal, CVD, and wet-cleaning process modules. Standard sizes ship from stock. Custom components are made to drawing from the same Lianyungang facility.
Process & Diffusion Tubes
The process tube is the heart of every thermal furnace stack. FGQuartz makes tubes for both horizontal and vertical furnace configurations. Applications include oxidation, diffusion, annealing, and CVD.
Clear fused silica is available for pyrometry-enabled furnaces. Opaque grade is available for insulating liner duty. Tube ends come plain, flanged, or ground to sealing surfaces. All dimensions match major furnace platform standards.
Quartz Wafer Boats
A quartz wafer boat holds dozens of wafers in the furnace. It must keep precise slot positions across thousands of cycles. No warping. No particle generation. No slot-edge chipping.
FGQuartz boats are CNC-machined from solid quartz blocks. This gives better structural rigidity than rod-assembled designs. It also removes weld joints that can cause contamination. Flat-slot, V-groove, and U-groove profiles are available in all standard wafer sizes from 100 mm to 300 mm.
Gas Injectors & Injector Rings
Gas uniformity across the furnace load controls film thickness uniformity. FGQuartz injector tubes and rings are drilled with diamond tooling. We match hole patterns to your customer specification.
This gives precise control over the local gas flow profile. Our injectors are compatible with nitrogen, oxygen, HCl, TCA, SiH₄, and other standard process gases.
Quartz Tanks & Wet-Bench Vessels
Wet cleaning is the most chemically aggressive step in the fab. Quartz tanks must survive hot piranha, SC1, SC2, and HF-based cleaning sequences.
FGQuartz tanks are made by fusion welding. There are no adhesives. There are no gaskets. There are no metal fittings that could leach contamination. Overflow weirs, drain spigots, and heater housings are built directly into the quartz body.
Flanges, Endcaps & Liners
Furnace hardware is just as important as the process tube itself. FGQuartz makes flanges and endcap assemblies with polished sealing faces. These work with O-ring or knife-edge vacuum interfaces.
We also make opaque quartz liners for thermal insulation. All hardware is dimensionally matched to the process tube it accompanies. This ensures compatible thermal expansion during furnace cycling.
Custom CNC-Machined Semiconductor Quartzware
New tool generations often need quartzware that no catalogue supplies. FGQuartz runs a dedicated CNC machining centre with diamond and CBN tooling. We can turn, mill, drill, and grind fused silica into complex three-dimensional parts.
Customers send drawings in DXF, STEP, or IGES format. We also accept sample parts for reverse engineering. Prototype quantities down to a single piece are welcome.
Semiconductor Quartz Glass Across Every Front-End Process Module
Select a process module below. Each tab explains which quartz components are involved and why semiconductor quartz glass is the right material for that step.
Diffusion Furnaces & Tube Furnaces
Thermal diffusion is one of the oldest steps in semiconductor manufacturing. It is still widely used today. Boron, phosphorus, arsenic, and antimony are driven into the silicon crystal at high temperatures. This creates the doped regions that define transistor behaviour.
The quartz process tube holds this chemistry. Its purity is non-negotiable. Any metallic impurities that leach from the tube wall will ruin the device. Gate oxide growth by thermal oxidation demands even higher tube cleanliness.
FGQuartz diffusion tubes are available for 150 mm, 200 mm, and 300 mm wafer batches. Matching endcap and flange hardware ships in the same quartz grade. This ensures compatible thermal behaviour during furnace cycling.
Chemical Vapour Deposition Furnaces
CVD processes deposit thin films onto wafer surfaces. These include polysilicon, silicon nitride, silicon dioxide, and tungsten. The films form when reactive gas breaks down at high temperatures.
Low-pressure CVD (LPCVD) runs at sub-atmospheric pressures. This improves film uniformity across the wafer batch.
The gas injector is the most geometry-sensitive component in an LPCVD system. The reactive gas is consumed as it flows through the tube. A simple end-feed design gives thick films at the inlet and thin films at the exhaust. Injector tubes with precisely positioned holes compensate for this effect.
FGQuartz makes injector tubes and rings to your specified hole pattern. This pattern is typically derived from CFD modelling of the specific tool.
Annealing & Thermal Treatment
Ion implantation damages the silicon crystal. It also leaves most dopant atoms in the wrong positions. Annealing fixes this. It heals crystal damage and activates the dopant electrically.
Rapid thermal annealing achieves this in seconds. Furnace annealing takes longer but processes larger batches.
In furnace annealing, opaque quartz liners improve temperature uniformity along the tube length. This gives better wafer-to-wafer thermal consistency.
For RTP systems, a quartz window sits between the lamp array and the wafer. It transmits intense near-infrared radiation to the silicon surface. The optical quality of this window directly affects temperature uniformity across the wafer.
Wet Chemical Cleaning
Wet cleaning happens at multiple points in the wafer flow. It removes particles, metallic contaminants, and surface films. The RCA clean sequence uses hydrogen peroxide with ammonia or HCl at elevated temperatures. Piranha strips heavy organics. HF removes native oxide.
Quartz tanks are the standard vessel for all of these chemistries. Fused silica resists every chemistry in this list except HF. For HF cleaning, we use specially selected quartz grades with minimal surface micro-defects.
All FGQuartz wet-bench tanks are fusion-welded from flat quartz plate. There are no adhesive joints. There are no metal fittings inside the chemical zone. This removes the contamination risks common in gasketed or epoxy-bonded assemblies.
Silicon Epitaxial Growth
Epitaxial silicon grows a single-crystal silicon layer on the wafer surface. The dopant profile in this layer is precisely controlled. This process demands an extremely clean thermal environment.
In barrel-type epitaxial reactors, a large quartz bell jar encloses the susceptor and wafer stack. The bell jar must be transparent to near-infrared radiation. This allows the lamp array to heat the susceptor through the jar while the jar itself stays relatively cool.
In-situ HCl etching periodically cleans the reactor walls. The quartz bell jar must survive this treatment without generating particles. FGQuartz supplies bell jars, liner tubes, and auxiliary quartz hardware for both atmospheric and reduced-pressure epitaxial reactors.
Gate Oxide Growth & Dielectric Processes
Gate oxide growth is one of the most demanding processes in the fab. A thin silicon dioxide layer forms the gate dielectric in every transistor. Its quality determines transistor switching speed and leakage current.
The quartz tube furnace is the standard tool for growing this layer. The purity of the process tube is critical at this step. Any trace sodium or iron from the tube wall degrades the oxide quality directly. This reduces device performance and wafer yield.
FGQuartz supplies high-purity semiconductor quartz tubes for gate dielectric growth. We match existing tube specifications or develop new dimensions for your tool. Endcaps and gas handling hardware are available in the same quartz grade.
Understanding Semiconductor Quartz Glass in the Fab
Choosing the right quartz component goes beyond dimensions alone. Grade selection, surface preparation, and handling all affect cleanroom results.
Clear vs. Opaque Quartz: Choosing the Right Grade
Clear and opaque quartz are both made from silicon dioxide. However, they behave very differently. Opaque quartz contains microscopic voids. These voids scatter and absorb light instead of transmitting it.
Use clear quartz when light transmission matters. Examples include process tubes observed by pyrometry, UV lamp envelopes, and RTP windows.
Use opaque quartz when thermal insulation matters. Examples include furnace liners, baffles, and spacers. Mixing the grades incorrectly causes heat leakage. It also creates temperature non-uniformity across the wafer batch.
Low-OH vs. Standard-OH Quartz: The Hydroxyl Question
Hydroxyl (OH) groups inside the quartz glass network affect its optical behaviour. They are most important in two wavelength regions.
High-OH (wet) quartz transmits UV light more effectively. Choose it for deep-UV lithography, excimer laser optics, and UV sterilisation applications.
Low-OH (dry) quartz is the better choice for LPCVD and high-temperature furnace work. Residual moisture from high-OH quartz can affect film chemistry. It can also introduce unwanted oxygen contamination into the process ambient. Specifying the wrong grade leads to subtle but measurable film property shifts across the batch.
Quartz Tube Lifecycle and When to Replace
Quartz process tubes do not last forever. Repeated thermal cycling builds up stress over time. Exposure to HCl, dopant vapours, and deposition gases gradually changes the inner surface chemistry.
Devitrification is the most important failure mode to watch for. It is a crystallisation process that produces a milky, opaque layer on clear quartz. It happens when tubes are held at high temperatures for extended periods. Alkali contamination makes it much worse.
Devitrified quartz is structurally weaker and generates particles. Check tubes regularly for surface milkiness, cracking at flange joints, and slot-edge chipping. Replace proactively. Never wait for failure in a production environment.
Pre-Use Cleaning and Qualification Protocols
New quartz components must be cleaned before entering a production furnace. They also need thermal pre-conditioning.
The standard protocol has three steps. First, clean with acid. Then rinse with DI water and dry completely. Finally, pre-bake in a dedicated qualification furnace. This removes surface contamination from manufacturing and machining. It also allows the quartz to outgas adsorbed water before it contacts product wafers.
FGQuartz can supply components pre-cleaned to incoming inspection standards. This reduces the lab work required at your site.
Natural vs. Synthetic Fused Silica for Semiconductor Applications
Fused silica is produced by two different routes. Natural fused silica comes from melting high-purity natural quartz crystals. Careful raw material selection achieves very low metallic impurity levels.
Synthetic fused silica is produced by flame hydrolysis or CVD of silicon precursors such as SiCl₄. This achieves the highest purity levels available. However, it carries a significant price premium.
For most semiconductor furnace quartzware, natural high-purity fused silica is the right choice. It gives the required contamination performance at a much more competitive price. FGQuartz advises on grade selection based on your process node and contamination budget.
Handling and Storage Best Practices
Quartz glass components are fragile, and contamination from bare-hand contact — sodium and potassium from skin oils — can persist through cleaning and reintroduce contamination during high-temperature processing. All quartz components should be handled with clean nitrile or latex gloves in a cleanroom or clean-bench environment. Storage should be in sealed polyethylene bags away from HF vapour, humidity, and vibration. Tubes should be stored horizontally on padded supports to prevent long-term sag under their own weight. FGQuartz packages all outgoing components in cleanroom-grade materials and includes handling guidance with each shipment.
Frequently Asked Questions
Common questions from procurement engineers, process engineers, and equipment manufacturers working with semiconductor quartz glass.
Clear fused silica transmits visible, UV, and infrared light. It is used for process tubes where in-situ pyrometry reads through the tube wall, for RTP windows, and for UV lamp envelopes. Opaque quartz contains microscopic closed voids that scatter and absorb light, giving it much lower thermal emissivity. It behaves as a thermal insulator and is used for furnace liners, baffles, and spacers where heat shielding is required. Choosing the wrong grade leads to unexpected temperature non-uniformity: a clear tube where an opaque liner is needed allows heat to escape to the furnace body; an opaque tube where optical access is needed blocks the pyrometer signal entirely.
Yes. FGQuartz accepts drawings in DXF, STEP, or IGES formats. For customers who do not have drawings — for example, when replicating a worn-out legacy component whose original drawings are unavailable — the sample part is measured on a coordinate measuring machine and a new production drawing is created in-house. Prototype quantities down to a single piece are accommodated. Once the prototype is approved, production quantities follow the same machining programme with no additional qualification lead time.
FGQuartz manufactures the complete range of front-end quartzware: process tubes and diffusion tubes in both horizontal and vertical configurations; wafer boats and carriers for 100 mm through 300 mm wafer generations; gas injectors and injector rings for LPCVD and CVD furnaces; flanges, endcaps, and push rods; furnace liners in clear and opaque grades; quartz tanks and wet-bench vessels; thermocouple protection tubes; and fully custom CNC-machined parts produced to customer drawings or reverse-engineered from sample components.
Quartz glass combines properties that no other common material matches simultaneously: extreme thermal stability, near-zero thermal expansion to survive repeated furnace cycles without cracking, near-total chemical inertness against the acids and process gases used in wafer processing, and inherent high purity that prevents metallic contamination of the silicon lattice. Alumina and silicon carbide match some of these individually but not all together at the cost point that fused silica delivers. Borosilicate glass covers a fraction of the temperature range. Quartz glass is the only practical choice for front-end furnace environments above approximately 800 °C.