Quartz Wafer Boat

Quartz Wafer Boats

Wafer boats hold silicon wafers vertically during thermal processing in horizontal furnaces, or horizontally in vertical furnace designs. The boat’s dimensional accuracy controls wafer-to-wafer spacing, gas flow uniformity, and contamination levels throughout the batch process.

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Standard Specifications

Horizontal Boat (Standard Slot Configuration)

Wafer Size	Slots (Standard)	Slot Pitch	Overall Length	Height	Material
4” (100 mm)	25	4.76 mm	130 mm	130 mm	Grade 1
6” (150 mm)	25	6.35 mm	175 mm	180 mm	Grade 1
8” (200 mm)	25	7.62 mm	215 mm	230 mm	Grade 1/2
12” (300 mm)	25	9.52 mm	265 mm	335 mm	Grade 2

Custom slot counts and pitches can be reviewed based on wafer format, drawing, and handling requirements.

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Vertical Boat (for Vertical Furnaces)

Vertical boats use a tube-and-rod construction with precision-slotted rings at defined pitch.

Wafer Size	Standard Slots	Slot Pitch	Overall Height
8” (200 mm)	100	4.76 mm	520 mm
12” (300 mm)	100	7.62 mm	820 mm

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Slot Geometry

The slot geometry must accommodate wafer thickness variation and prevent sticking while maintaining a near-vertical seating angle for uniform gas exposure.

Feature	Standard	Tight-Tolerance
Slot width	Based on wafer thickness and clearance requirement	Reviewed for tighter clearance where required
Slot depth	Reviewed by wafer support requirement	Reviewed by wafer support requirement
Seating angle	Reviewed by handling and process requirement	Reviewed by handling and process requirement
Slot pitch	Reviewed by drawing	Reviewed by drawing
Slot parallelism	Reviewed by drawing	Reviewed by drawing

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Material Selection

• Grade 1 (Natural fused quartz): Commonly reviewed for general furnace processes where the material certificate and cost target fit the application
• Grade 2 (Synthetic fused silica): Reviewed for processes with tighter trace-metal requirements, depending on material source and order scope

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Accessories

Quartz wafer boats are typically used with:

• Quartz push rods — for loading/unloading boats from furnace tubes
• Quartz baffles — gas flow conditioning at boat ends
• Quartz cantilever paddles — for large-diameter wafer handling