High Power Pulsed Magnetron (HPPMS)
High power pulsed magnetron sputtering (HPPMS/HIPIMS) has the ability to produce thin film coatings with excellent adhesion, density, and low surface roughness. This is primarily due to the intense pulsed plasma producing a high density of metal ions.
Used in semiconductor manufacturing
One of the most difficult problems of chip fabrication is trying to deposit coatings into high aspect ratio trenches. The dimensions continually get smaller and therefore interconnect trenches become narrower, but still remain relatively deep. These interconnect trenches are coated with a diffusion barrier such as titanium nitride, TiN and then metalized. Depositing these materials uniformly into the trench is difficult as PVD is a line of sight coating technique and in modern chip designs aspect ratios can be as high as 7:1. In the past thermal evaporation was able to deposit the required coatings but this technique became obsolete as chip designs became smaller and more efficient. At the moment a coating technique known as Ionized Physical Vapor Deposition (IPVD) is used. In IPVD sputtered material is ionized and then steered into the trench using a voltage bias. Using IPVD the trench can be filled quite uniformly.
Generally IPVD requires a secondary plasma source to ionize a high enough percentage of the sputtered material. This makes it a complex technique that can be difficult to scale up. HPPMS may provide a highly scalable means of depositing diffusion barrier coatings and metallic features in the high aspect ratio interconnect trenches. This is because a HPPMS power supply can be connected to any existing deposition system to increase the ionization rate.