What is magnetron sputtering technology?
Magnetron sputtering is another form of PVD coating technology.
Magnetron sputtering is a plasma coating process whereby sputtering material is ejected due to bombardment of ions to the target surface. The vacuum chamber of the PVD coating machine is filled with an inert gas, such as argon. By applying a high voltage, a glow discharge is created, resulting in acceleration of ions to the target surface and a plasma coating. The argon-ions will eject sputtering materials from the target surface (sputtering), resulting in a sputtered coating layer on the products in front of the target.
Often an additional gas such as nitrogen or acetylene is used, which will react with the ejected material (reactive sputtering). A wide range of sputtered coatings is achievable with this PVD coating technique. Magnetron sputtering technology is very advantageous for decorative coatings (e.g. Ti, Cr, Zr and Carbon Nitrides), because of its smooth nature. The same advantage makes magnetron sputtering widely used for tribological coating in automotive markets (e.g. CrN, Cr2N and various combinations with DLC coating - Diamond Like Carbon coating).
Magnetron sputtering is somewhat different from general sputtering technology. The difference is that magnetron sputtering technology uses magnetic fields to keep the plasma in front of the target, intensifying the bombardment of ions. A highly dense plasma is the result of this PVD coating technology.
Magnetron sputtering technology is characterized by:
- A water-cooled target, so little radiation heat is generated
- Almost any metallic target material can be sputtered without decomposition
Non-conductive materials can be sputtered by using radio frequency (RF)
or medium frequency (MF) power
- Oxide coatings can be sputtered (reactive sputtering)
- Excellent layer uniformity
- Very smooth sputtered coatings (no droplets)
Cathodes (of up to 2 meter long) can be put in any position, therefore high
flexibility of sputtering equipment design
Magnetron sputtering technology has some disadvantages:
- Slow deposition speed compared to arc technology
Lower plasma density (~5%) compared to arc technology; adhesion of coatings is
lower and density of the sputtered layers may be lower
Magnetron sputtering technology has many forms, of which we will explain a few. These sputtering technologies are all available in Hauzer Flexicoat® equipment:
Unbalanced Magnetron Sputtering (UBM) is a PVD coating technology that uses extra magnetic coils to intensify the plasma close to the product. The result is a more dense sputtered coating. Because more energy is involved in unbalanced magnetron sputtering, the temperatures during process are higher
Closed Field Magnetron Sputtering uses magnetic fields in such a way that the plasma is caged in. Less target material is lost to the chamber walls and the plasma moves closer to the substrate. The result is a dense sputtered coating, while the walls of the vacuum chamber remain relatively clean
- Dual Magnetron Sputtering (DMS) is a PVD coating technology used to apply non-conductive coatings. An alternating current (AC) is used between the sputter cathodes, instead of a direct current (DC) between sputter cathode and wall. Thus it achieves a self-cleaning effect of the targets. Dual magnetron sputtering is used for deposition of e.g. oxide coating at high speed
HIPIMS is very suitable for etching and coating.
- High Power Impulse Magnetron Sputtering (HIPIMS) is a PVD coating technology which uses a high pulsed power source to increase the ionisation of sputtered material. The coating applied with HIPIMS technology achieves the advantages of both arc technology and magnetron sputtering. They create a dense sputtered layer with good adhesion, which is also extremely smooth.
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