Atomic layer deposition (ALD) is an ideal technique for fabricating thin layers requiring precision-controlled nanoscale film thickness. It is a type of chemical vapor deposition (CVD), wherein a film is built up through deposition of multiple ultra thin layers of atomic level controllability, with the thickness of the ultimate film being determined by the number of layers deposited.

For many decades, dry processing techniques, such as physical vapor deposition (PVD), have played a dominant role in integrated circuit metallization processes. During microelectronic device fabrication, films are often deposited on non-planar surfaces. The surface topography that wafers exhibit at various steps in the fabrication process arise from patterned features related to, for example, trenches andor vias.