The development of ionized physical vapor deposition (IPVD) was mainly driven by the formation of metal and nitride thin films into deep, narrow trences and vias that are essential in modern microelectronics [1]. More recently, the control of the ion energy and direction of the deposition species has proved to be an important physical tool in the growth process of new materials and new structures. In a conventional dc magnetron sputtering discharge ions are abundantly available, but the ions are dominated by the ions of the inert sputtering gas and the ions of the sputtered material are rare. Over the past few years, various ionized sputtering techniques have appeared that show a high degree of ionization of the sputtered atoms, often in the range 50 - 90%. Here, the development and application of magnetron sputtering systems for ionized physical vapor deposition (IPVD) is reviewed [2]. The application of a secondary discharge to a magnetron sputtering discharge, either inductively coupled plasma source (ICP-MS) or a microwave amplified magnetron sputtering is currently widely used. High power impulse magnetron sputtering (HiPIMS) is a more recent sputtering technique that utilizes ionized physical vapor depositon (IPVD). High density plasma is created by applying a high power pulse to a planar magnetron discharge. Essential to these methods is the high electron density which results in a high degree of ionization of the deposition material. Other methods exist such as the self-sustained sputtering (SSS) magnetron discharge, and the hollow cathode magnetron (HCM) sputtering discharges. Examples of the use IPVD-techniques for growth of thin films of higher density, coatings with improved adhesion, improved coverage of complex shaped substrates, and increased reactivity with higher deposition rate in reactive processes are reviewed.
[1] J. A. Hopwood, The role of ionized physical deposition in integrated
circuit fabrication, in: J.A. Hopwood, Editor, Thin Films: Ionized
Physical Vapor Deposition, Academic Press, San Diego (2000), p. 1.
[2] U. Helmersson, M. Latteman, J. Bohlmark, A. P. Ehiasarian, and
J. T. Gudmundsson, Ionized Physical Vapor Deposition (IPVD):
A Review of Technology and Applications, Thin Solid Films 513 (2006) 1-24 |