Patterning

Experimental resist patterns showing line uniformity and structure

Semiconductor manufacturing basically begins with lithography, which uses extremely narrow waves of light – in combination with sensitive chemicals called resists, and stencil-like devices know as photomasks – to create intricate patterns on a silicon wafer. Approximately one-third of the total cost of chip manufacturing involves lithography, or litho. As a result, litho must improve constantly in order to continue making chips faster, cheaper, and more powerful.

Current and future litho is taking several avenues to achieve finer and denser patterns. Some of the better known technologies include:

Immersion, using the well-known 193 nm wavelength with water or other fluids to take advantage of refraction and so create an even shorter, effective wavelength that can be used to inscribe chip patterns
Extreme ultraviolet lithography (EUV), which utilizes extremely short wavelengths (13.4 nm) of invisible light to create very narrow chip features
Charged-particle maskless, a relatively new version of litho that dispenses with masks and utilizes electrons, ions or other charged particles for patterning
Nanopatterning, an approach that uses the natural attractions and repulsions of matter to prompt molecules to form intricate patterns, similar to the way that water molecules are driven by weather conditions to form a snowflake.

Semiconductors

Patterning