The difficulty is that the wafer surface is not perfectly flat, but may vary by several micrometres.

High-energy ions from the plasma attack the wafer surface and react with it.

The pattern is projected and shrunk by four or five times onto the wafer surface.

Only the susceptor is heated, so gases do not react before they reach the hot wafer surface.

The wafer is initially heated to a temperature sufficient to drive off any moisture that may be present on the wafer surface.

During the first stage of oxidation, the chemical reaction results from the direct contact between silicon and oxidants at the wafer surface.

Plasma stripping is more effective with water vapor to help lift the film of the wafer surface.

These requirements are specified for the wafer surface as sufficiently clean, flat and smooth.

White light interferometry is commonly used for detecting deformations of the wafer surface based on optical measurements.

All the cantilevers are made entirely out of silicon, using surface micromachining at the wafer surface.