**1. Introduction**

Greene, J. E. [1] reported that the sputter deposition, described in the early 1800s, had already controlled the optical-coating industry by 1880. In 1891, radio frequency (rf) glow discharges were recorded. The term "magnetron" first appeared in literature in 1921, and the first magnetron sputtering experiments were reported in the late 1930s. In the early 1960s, capacitively-coupled rf sputtering devices were conceived and modeled. The first reactive sputtering kinetic models appeared in the 1960s. Parallel-plate magnetron was described in 1962. In 1975, a patent was submitted that led to pulsed dc and mid- frequency-ac sputtering. In the early 1980s, rotatable magnetrons were introduced. During the 1990s, two new types of magnetron sputtering emerged, both with the purpose of effectively ionizing sputter-ejected metal atoms. In 1992, tunable "unbalanced" magnetron sputtering was invented [1]. Historical flowchart is represented by **Figure 1**.
