Novel approach to collimated physical vapor deposition

In some applications of physical vapor deposition (PVD), it is desirable to have the atoms arriving at the substrate at angles close to the normal (collimation). Applications of collimated PVD include continuous coverage of high-aspect ratio vias, as used in multilevel integrated circuit metallization, or high resolution shadow masking as used in lift-off technology. Several approaches to collimation have been proposed in recent years: natural (or long throw) collimation, physical collimation, ion beam deposition, ionized PVD cathodic are deposition and hollow cathode collimation. In this article, we introduce a novel approach to collimation. According to simulations of target-to-substrate atom transport using the SIMBAD program this approach provides narrow angular distribution functions of the sputtered flux at the substrate surface. Furthermore, it is shown experimentally that this approach leads to a strongly improved degree of collimation when compared to the conventional methods based on either physical or natural collimation, through formation of abutted junction permanent: magnet stabilization and metallization layers as in applied magnetoresistive thin film recording heads, using a lift-off process. (C) 1999 American Vacuum Society. [S0734-2101(99)18304-0].