High power pulsed magnetron sputtering (HPPMS/HIPIMS) can generate materials with very low surface roughness and great adhesion. This is mostly caused by the strong pulsed plasma that generates a lot of metal ions.
Used in semiconductor manufacturing
Depositing coatings into high aspect ratio trenches is one of the trickiest issues with chip production. The connecting trenches continue to get deeper while also getting narrower as the dimensions get smaller. These connecting trenches are metalized after being coated with a diffusion barrier, such as titanium nitride, TiN. Due to the fact that PVD is a line-of-sight coating process and that aspect ratios in contemporary chip designs can reach 7:1, it is challenging to deposit these materials uniformly into the trench. The necessary coatings could once have been deposited by heat evaporation, but as chips got smaller and more effective, this method was rendered ineffective. The coating method now in use is called Ionised Physical Vapour Deposition (IPVD). By applying a voltage bias, sputtered material is ionised in IPVD before being guided into the trench. The trench can be filled pretty consistently using IPVD.
A secondary plasma source is typically needed for IPVD in order to ionise a sufficient amount of the sputtered material. Due of this, scaling up the process can be challenging. Diffusion barrier coatings and metallic features may be deposited using HPPMS in high aspect ratio connection trenches in a very scalable manner. This is due to the fact that any existing deposition system can have its ionisation rate increased by connecting an HPPMS power source to it.