Custom fused silica wafer carriers · 2–12 inch and solar formats
Quartz Wafer Boats
A quartz wafer boat — also called a quartz boat or wafer carrier — is a high-purity fused silica carrier that holds semiconductor or solar wafers upright and evenly spaced inside a furnace tube during diffusion, oxidation, LPCVD, and annealing, without introducing metallic contamination.
FGQuartz manufactures horizontal wafer boats, vertical wafer boats (towers), solar cell boats, and laboratory sample boats from fused quartz with SiO₂ ≥ 99.99%, for 2–12 inch (50–300 mm) wafers and M10 / G12 solar formats. Slot count, pitch, angle, groove profile, boat length, and end-plate design follow the customer drawing, with diamond-machined slots and fire-polished contact edges to reduce particle generation and wafer edge damage. Custom manufacturing is available from a single prototype, with no minimum order quantity.
Quick answer
What is a quartz wafer boat used for? A quartz wafer boat holds semiconductor or solar wafers upright and evenly spaced during high-temperature furnace processes such as diffusion, oxidation, LPCVD, and annealing, without introducing metallic contamination.
Key takeaways
- FGQuartz boats support 2–12 inch (50–300 mm) semiconductor wafers and M10 / G12 solar formats, with custom slot counts such as 25, 50, 100, and 150+.
- Slot pitch sets wafer-to-wafer spacing; inaccurate pitch causes uneven gas flow or thermal exposure and affects process uniformity and yield.
- Fire polishing after CNC slotting seals micro-cracks and reduces particle shedding.
- Quartz boats are transparent and inert and rated to about 1200°C; SiC boats take higher temperatures but are opaque.
Written by the FGQuartz Engineering Team · Updated October 2026
On this page: Specifications · Horizontal or vertical · Quartz vs SiC · Boat types · Project examples · Applications · FAQ and quote
Lead time depends on size and drawing complexity; the quote confirms the schedule.
What quartz wafer boats are specified for
Product features
Quartz wafer boat specifications
Technical specifications
Values below are FGQuartz published ranges for fused silica boats. Slot geometry, tolerances, and structure are set from the drawing and confirmed in design-for-manufacture (DFM) review.
| Parameter | Specification |
|---|---|
| Material | High-purity fused quartz / fused silica (SiO₂ ≥ 99.99%). Clear or opaque when specified. |
| Wafer / substrate size | 2 in to 12 in (50–300 mm) semiconductor wafers, M10 / G12 solar formats, and custom substrates. |
| Slot count | Per drawing, for example 25, 50, 100, or 150+ slots, from small sample boats to full-load carriers. |
| Slot pitch and profile | Specified from the drawing (pitch, slot width, depth, angle, V-groove or flat-bottom profile) and confirmed in DFM review. |
| Boat length | Made to the furnace tube and load zone. Length follows the drawing. |
| Structure | Rod-and-end-plate welded boats, machined-from-tube boats, half-shell designs, and vertical tower assemblies. |
| Working temperature | Continuous to 1200°C, short-term to 1300°C. |
| Purity | SiO₂ ≥ 99.99%. Trace metals and OH vary by grade. |
| Surface finish | Fire-polished contact edges and slot entries, annealed after hot work. Sandblasted or ground surfaces on request. |
| Processing | Diamond cutting, CNC slotting, core drilling, oxy-hydrogen flame welding, fire polishing, annealing. |
| Customization | Build-to-print from DXF, STEP, IGES, or PDF. Single prototypes through production. No MOQ. |
Full thermal, mechanical, optical, and chemical tables: Technical Specifications. Load capacity and slot tolerance are set per drawing — they are not catalog numbers.
Horizontal or vertical: choosing the boat
Boat selection
The boat type is set by the furnace, not by preference. Horizontal boats slide into a horizontal tube and hold wafers standing on edge along the tube axis. Vertical boats (towers) stack wafers flat inside vertical furnaces and are supported on a pedestal or cap.
Wafer size drives the design. Larger wafers need deeper slots, stiffer rods, and tighter support spacing to avoid slip lines and bowing at temperature. Slot pitch accuracy matters because it sets the spacing between wafers, and with it gas flow and thermal exposure across the batch. Send the wafer diameter, thickness, and furnace tube ID so slot geometry and boat envelope can be matched. Boats load into quartz glass tubes; see also What is quartz glass?
Typical properties of fused silica
Typical values for high-purity fused silica. Optical transmission and OH content vary by grade.
| Continuous service | 1200°C |
| Short-term maximum | 1300°C |
| Softening point | ≈ 1680°C |
| Annealing point | ≈ 1215°C |
| Strain point | ≈ 1120°C |
| Thermal expansion (20–300°C) | 5.5 × 10⁻⁷ /°C |
| Thermal conductivity (20°C) | ≈ 1.4 W/(m·K) |
| Density | ≈ 2.2 g/cm³ |
Chemical note: excellent resistance to HCl, HNO₃, H₂SO₄, aqua regia, and organic solvents. Attacked by HF, hot concentrated phosphoric acid, and hot strong alkalis.
Quartz boat vs SiC boat
Comparison
Both carry wafers through high-temperature furnace steps. The choice turns on temperature, visibility, and contamination risk.
| Point | Quartz boat | SiC boat (solid or coated) |
|---|---|---|
| Temperature | Rated to about 1200°C continuous. | Higher temperatures. |
| Visibility | Transparent; allows visual process monitoring. | Opaque. |
| Chemical behavior | Chemically inert. | Solid SiC is robust; coated versions carry contamination risk if the coating degrades. |
| Best for | Standard diffusion, oxidation, LPCVD, and anneal steps within quartz temperature limits. | Steps that exceed quartz temperature limits. |
General comparison for orientation; confirm against your process temperature and cleanliness requirements.
Boat types we fabricate
Customization
FGQuartz does not publish a fixed boat SKU list. Each boat is made to your wafer size, load, and furnace, from a single prototype to production, with no minimum order quantity. Non-boat custom parts are on the custom quartz glass page.
| Boat type | Typical use | What is fabricated |
|---|---|---|
| Horizontal wafer boats | Horizontal diffusion, oxidation, and anneal furnaces | Rod-and-end-plate boats with CNC-slotted rails for 2–12 in wafers. |
| Vertical wafer boats (towers) | Vertical LPCVD and batch furnaces | Multi-rod towers with slotted supports, base rings, and top plates. |
| Solar cell boats | POCl₃ diffusion and PV thermal steps | Large-format boats for M10 / G12 and other square cells, with wide slots and stable spacing. |
| Half-shell and machined-from-tube boats | Compact loads and specific furnace tubes | Half-shell designs and boats machined from tube stock, to drawing. |
| Sample and combustion boats | Laboratory heating, ashing, and combustion analysis | Open trough boats in standard or custom lengths with fire-polished edges. |
| Custom carriers | Non-standard substrates, masks, and fixtures | Build-to-print carriers, trays, and holders from CAD or a qualified sample, with custom slot pitch, angle, and groove profile. |
Slots are diamond-machined and fire-polished, then the boat is annealed as one part.
Representative wafer boat builds
Project examples
Three typical custom boat projects, described by the requirement, the build route, and what is checked against the drawing. Customer names and confidential drawing data are withheld.
01 · Diffusion furnace
Horizontal wafer boat
Requirement. A boat that holds a batch of wafers at a fixed pitch inside a horizontal diffusion tube.
How it is built. Rods cut and CNC-slotted to the specified pitch, welded to end plates, slot entries fire-polished, annealed as one part.
Checked against the drawing. Slot pitch, slot depth, boat length, and squareness.
02 · Vertical furnace
Vertical wafer tower
Requirement. A stacked carrier for a vertical LPCVD or batch furnace.
How it is built. Multi-rod tower with slotted supports, base ring, and top plate welded and annealed.
Checked against the drawing. Support spacing, overall height, and ring dimensions.
03 · Solar
Large-format cell boat
Requirement. A carrier for square solar cells in POCl₃ diffusion with stable spacing.
How it is built. Wide slots CNC-machined on welded rails sized to the cell format, fire-polished and annealed.
Checked against the drawing. Slot width and pitch, boat length, and rail alignment.
Machined, welded, and annealed under one ISO 9001 system
Manufacturing and quality
FGQuartz operates a 15,000 m² facility in Lianyungang covering CNC diamond machining, oxy-hydrogen flame welding, fire polishing, and annealing, so slotting, assembly, and stress relief happen in one plant. Learn more about FGQuartz.
Handling and cleaning: clean with an acid bath or alcohol wipe before high-temperature use. Alkali salts and fingerprints catalyze devitrification above roughly 1150°C, so regular cleaning and checks for devitrification help control particles in service. Load and unload wafers with a paddle or tweezers, never by forcing wafers into slots.
Quartz wafer boat applications
Applications
Why specify FGQuartz
Manufacturer
Procurement questions
FAQ