The simple definition of glancing angle deposition is deposition under an angle during rotation. It is mainly used in evaporation processes, but sometimes also in sputtering processes. In glancing angle deposition (GLAD) a substrate is tilted to a glancing angle during deposition of the target material. Thereby, an oblique deposition geometry is created on the surface of the substrate. Generally, during thin film formation, the impinging atoms condense on the surface, spontaneously forming atomic nuclei. Ballistic (line-of-sight) shadowing prevents the incoming atoms from impinging on the regions behind the nuclei, resulting in the formation of oriented columns that are tilted towards the target source. It is possible to control the column growth direction by manipulating the rotation and tilt angle of the substrate during deposition. The combination of shadowing and rotation of the substrate enables the evolving film to serve as its own mask, which can be actively controlled during the process to direct the growing columns into a preferred geometry. Several geometries can be obtained, including zigzag, helical, vertical, and hollow-core structures.
An industrial concept for glancing angle deposition on 200mm wafers has been developed and manufactured based on our Flextura PVD platform, which you can read more about here. High volume production with GLAD processes has been realised on our Flextura Cluster platform, with the know-how and expertise from the Polyteknik AS team.