Technology

Plasma etching

We always strive to achieve high-quality, defect-free, and durable PVD coatings. That is why plasma etching is so important.

Plasma etching is a process used to remove surface material from a substrate using a plasma. The plasma is a highly ionized gas containing ions, electrons, and neutral atoms. A process gas (like argon) is introduced into the vacuum chamber, and a pulsed electric field is applied to generate the plasma. The ions bombard the substrate, effectively etching away the unwanted surface layer.

Plasma etching is crucial prior to PVD coating as it ensures that the substrate’s surface is clean and free of contaminants, enhancing the adhesion and quality of the coating. Mainly by removing thin surface layers of organic impurities and oxides, plasma etching provides a fresh surface that promotes better chemical bonding between the substrate and the coating material. Applied to plastics, plasma etching can also activate the surface by introducing functional groups, by using for example nitrogen or oxygen gas. Such reactive groups will chemically bind to the coating material.

It is also possible to utilize metal ions in etching, a process known as metal ion etching. This process promotes an even stronger chemical bonding between the substrate and the coating material through a mechanism where metal atoms are implanted into the outer surface layer of the substrate. It creates a microscopic gradient-like interface between the substrate and the coating, and this effect is beneficial for applications where properties like high corrosion resistance and wear resistance are desired. Some metals commonly used for metal ion etching are chromium and titanium.

Key features and benefits of plasma etching

Limitations

• Plasma etching is not a substitute for wet cleaning. It cannot remove grease, oils, fingerprints, tape residue, pen markings, etc.