Overview
A wafer is a thin, circular slice of semiconductor crystal (usually silicon) that serves as the foundation for building microchips. Multiple chips are fabricated simultaneously on a single wafer before being cut into individual dies.
Characteristics
- Size: Modern wafers are typically 300mm (12 inches) in diameter, with 450mm being a future target.
- Purity: Must be extremely pure (99.9999999% or 'nine nines') to ensure reliable circuit operation.
- Orientation: The crystal lattice orientation affects the electrical properties of the devices built upon it.
Manufacturing Role
The number of chips per wafer (yield) is a critical factor in the cost and efficiency of semiconductor manufacturing.