- High Power Impulse Magnetron Sputtering
High Power Impulse Magnetron Sputtering (HIPIMS, also known as High Impact Power Magnetron Sputtering and High Power Pulsed Magnetron Sputtering, HPPMS) is a method for
physical vapor depositionof thin filmswhich is based on magnetron sputter deposition. HIPIMS utilises extremely high power densities of the order of kWcm-2 in short pulses (impulses) of tens of microseconds at low duty cycle(on/off time ratio) of < 10%.
HIPIMS is used for:
*adhesion enhancing pretreatment of the substrate prior to coating deposition (substrate etching)
*thin film deposition
The first patent on HIPIMS was filed by Vladimir Kouznetsov (priority date 9 Dec 1997), Kouznetsov US 6296742 B1.
HIPIMS Plasma Discharge
HIPIMS plasma is generated by a glow discharge where the discharge current density can reach up to 6 Acm-2, whilst the discharge voltage is maintained at several hundred volts.Citation
title=Influence of High Power Densities on the Composition of Pulsed Magnetron Plasmas
doi=10.1016/S0042-207X(01)00475-4 .] The discharge is homogeneously distributed across the surface of the cathode of the chamber.HIPIMS generates a high density plasma of the order of 1013 ions cm-3 containing high fractions of target metal ions.The ionisation degree of the metal varpour is a strong function of the peak current density of the discharge. At high current densities, sputtered ions with charge 2+ and higher - up to 4+ for Ti - can be generated. The appearance of target ions with charge states higher than 1+ is responsible for a potential secondary electron emission process that has a higher emission coefficient than the kinetic
secondary emissionfound in conventional glow discharges. The establishment of a potential secondary electron emission may enhance the current of the discharge.
HIPIMS is typically operated in short pulse (impulse) mode with a low
duty cyclein order to avoid overheating of the target and other system components. In every pulse the discharge goes through several stages:
*steady state, which may be reached if the metal plasma is dense enough to effectively dominate over the gas plasma
ubstrate pretreatement by HIPIMS
Substrate pretreatment in a plasma environment is required prior to deposition of thin films on mechanical components such as automotive parts, metal cutting tools and decorative fittings. The substrates are immersed in a plasma and biased to a high voltage of a few hundred volts. This causes high energy ion bombardment that sputters away any contamination. In cases when the plasma contains metal ions, they can be implanted into the substrate to a depth of a few nm. HIPIMS is used to generate a plasma with a high density and high proportion of metal ions. When looking at the film-substrate interface in cross-section, one can see a clean interface.
Epitaxyor atomic registry is typical between the crystal of a nitride film and the crystal of a metal substrate when HIPIMS is used for pretreatment. [Citation
title=Interface microstructure engineering by high power impulse magnetron sputtering for the enhancement of adhesion
journal=Journal of Applied Physics
pages= item 054301, 10 pp.
doi=10.1063/1.2697052 .] HIPIMS has been used for the pretreatment of steel substrates for the first time in February 2001 by A.P. Ehiasarian.Citation
title=High Power Pulsed Magnetron Sputtered CrNx Films
journal=Surface and Coatings Technology
Thin Film Deposition by HIPIMS
Thin films deposited by HIPIMS at discharge current density > 0.5 Acm-2 have a dense columnar structure with no voids. Copper films deposited by HIPIMS are able to fill high aspect ratio trenches [ Citation
title=A novel pulsed magnetron sputter technique utilizing very high target power densities
journal=Surface and Coatings Technology
HIPIMS has been used for the deposition of
transition metalnitride (CrN) thin films for the first time in February 2001 by A.P. Ehiasarian. The films had a dense microstructure, were free of large scale defects and had low sliding wearcoefficient.
HIPIMS has been successfully applied for the deposition of thin films in industry. SVS Vacuum Coating Technologies GmbH is the first company which integrated HIPIMS into its R&D, pilot and industrial production coating machines routinely.
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