Chapter 4 - Physical Sputtering and Sputter Deposition

Abstract

Sputtering and sputter deposition using inductive pulsed high voltage was the first vacuum coating process. For about 75 years (1852–1920s) high-voltage pulses from induction coils were the principal source of voltage for physical sputtering. In the 1930s magnetic confinement of plasmas to increase the plasma density at low pressures began to be used and this led to the development of the sputter-ion vacuum pump. In the 1960s the demands of the integrated circuit and semiconductor industries led to the use of sputtering for elemental (e.g., Ta), alloy (e.g., Al:1%Si:1%Cu), multilayer (e.g., Ti-Cu-Au), and compound (e.g., TaN) deposition. The advent of high-rate, wide magnetron sputtering sources in the 1970s allowed the coating of large-area substrates such as for low-e coatings on architectural window glass. The 1970s also saw the development of solid-state power supplies that allowed a variety of waveforms as well as arc detection and suppression. With the advent of magnetron sputtering, controlled reactive sputter deposition, and the use of controlled concurrent ion bombardment of the depositing material as a process parameter, sputter deposition rapidly developed after the mid-1970s. In the 2000s the advent of high power impulse magnetron sputtering, with its high ionization of the sputtered material expanded the applications of sputtering. Major advantages of the magnetron sputtering sources are that they can provide a long-lived, high-rate, elongated, low-temperature vaporization source. The lack of radiant heating allows the sputtering source to be positioned close to the substrate.