Plasma etching

It involves a high-speed stream of glow discharge (plasma) of an appropriate gas mixture being shot (in pulses) at a sample.

The plasma source, known as etch species, can be either charged (ions) or neutral (atoms and radicals).

Three different processes can occur because of this collisions:[2][3] Different species are present in the plasma such as electrons, ions, radicals, and neutral particles.

One way to form a plasma is by using RF excitation by a power source of 13.56 MHz, a frequency allocated for this application in the ISM bands.

The main factors that influence the plasma process:[2][3][5] The reaction of the products depend on the likelihood of dissimilar atoms, photons, or radicals reacting to form chemical compounds.

Plasma etching has been reported to reduce the surface roughness from hundreds of nanometers to as much lower as 3 nm for metals.

A silicon wafer is placed in the plasma etcher, and the air is evacuated from the process chamber using a system of vacuum pumps.

Then a process gas is introduced at low pressure, and is excited into a plasma through dielectric breakdown.

Small features can be etched into the surface of the semiconducting material in order to be more efficient or enhance certain properties when used in electronic devices.

[3] For example, plasma etching can be used to create deep trenches on the surface of silicon for uses in microelectromechanical systems.

This application suggests that plasma etching also has the potential to play a major role in the production of microelectronics.

[5] Hydrogen plasma etching also tends to leave a clean and chemically balanced surface, which is ideal for a number of applications.

When used in conjunction with photolithography, silicon dioxide can be selectively applied or removed to trace paths for circuits.