Chip Manufacturing · Topic 3 of 16
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Chip ManufacturingLesson 3 of 16
Wafer
Slicing and polishing the ingot into mirror-flat wafers.
What you’ll learn
- How wafers are made from ingots
- Why flatness matters
- Standard wafer sizes
Why it matters
The wafer is the canvas on which hundreds of chips are patterned at once.
Explanation
The ingot is sliced into thin discs with a wire saw, then lapped, etched, and polished to an atomically smooth, defect-free surface. Edges are rounded and the crystal orientation is marked.
Extreme flatness is required so that lithography can focus sharply across the whole wafer.
Visual explanation
Key terminology
- Wafer
- A thin polished disc of single-crystal silicon.
- CMP
- Chemical-mechanical polishing used for flatness (see later lesson).
- Flat/notch
- A marking that indicates crystal orientation.
Example
A 300 mm wafer can yield hundreds to thousands of dies depending on chip size.
Common mistakes
Watch out for:
- Underestimating flatness requirements — nanometre-scale variation matters for lithography.
Real-world application
Yield (good dies per wafer) is a central economic metric.
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Wafer
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Oxidation
Chip Manufacturing
Growing a high-quality silicon dioxide layer on the wafer.
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