sputteretching

Sputter etching is a physical process used in semiconductor fabrication and materials science to remove material from a surface. It utilizes a plasma, typically an argon plasma, to bombard the target surface with energetic ions. When these ions strike the surface, they transfer their kinetic energy to the surface atoms, causing them to be ejected or "sputtered" away. This removal process is non-directional, meaning material is etched from all exposed surfaces.

The sputter etching process is typically carried out in a vacuum chamber. The chamber is filled with a low-pressure inert gas, such as argon. A radio frequency (RF) or DC power supply is then used to create a plasma from the gas. The substrate to be etched is placed on a powered electrode, which becomes negatively biased. This negative bias attracts the positively charged ions from the plasma, accelerating them towards the substrate surface. The rate of etching is influenced by factors such as the ion energy, ion flux, and the material's sputter yield.

Sputter etching is often employed for cleaning surfaces, removing thin films, and in processes where a precise etch profile is not critical. It is a relatively simple and effective method for material removal. However, due to its non-directional nature, it can lead to undercutting of features when used for patterning. This limitation is often overcome by using photoresist masks to define areas to be etched. In some applications, sputter etching is combined with chemical etching in a process called reactive ion etching (RIE) to achieve more selective and anisotropic etching.