For somewhat more than a decade, the intentional ionization of sputtered neutral atoms has been exploited to improve the directionality of sputter deposition. In addition to directional control, once a sputtered atom is ionized it is relatively easy to control its energy of deposition. Ionized sputtering is a subclass of the deposition technique commonly known as ionized physical vapor deposition (IPVD). The common characteristic of the many various IPVD techniques is that a neutral vapor, created by physical means including evaporation, sputtering, and ablation, is partially ionized using an intense secondary plasma. As the neutral vapor traverses this secondary discharge, the atoms are ionized by collisions with energetic electrons and metastable atoms. Due to the low ionization potential of most metals, the ionizing discharge need only have about 10@super 12@ electrons per cm@super 3@ with an electron temperature of ~ 2 eV. Atoms with high ionization potentials and small ionization cross sections, however, require significantly more intense secondary discharges. For this reason, reactive sputtering using IPVD may produce a high flux of oxygen or nitrogen atoms, but IPVD typically does not significantly ionize the reactive gas flow. Nonetheless, the depositing flux of metal may be as much as 80-90% ionized using IPVD. The physical mechanisms responsible for ionization will be briefly reviewed in the context of reactor design and process development. A primary user of IPVD is the semiconductor industry. The driving force for adopting IPVD was the need to deposit thin films into the high aspect ratio microstructures commonly found on modern integrated circuits. Conventional sputtering exhibits a cosine angular distribution of sputtered atoms that makes deposition of material into the bottom of deep submicron trenches and vias impossible. By simply applying a negative bias voltage to the wafer, however, ionized sputtered material can be accelerated perpendicular to the wafer surface such that the depositing flux provides adequate bottom coverage of microstructures. The common applications of IPVD include the deposition of copper seed layers used for the subsequent electroplating of copper interconnects, as well as the deposition of adhesion layers and barrier layers using reactively sputtered metal-nitrides. Examples of successful semiconductor processes that use IPVD will be discussed. Because many IPVD process tools require a complete sputtering system plus additional hardware for producing the secondary ionizing plasma, IPVD is a more complex and expensive process than conventional PVD. The secondary ionizing plasma may be produced by inductively coupled plasma, helicon resonators, or ECR plasma - all of which add cost and complexity. Recent advances, however, exploit single power source sputtering in which the secondary plasma is produced by the sputtering source. These simple techniques may allow for the broader use of IPVD in cost-sensitive applications.