A radio frequency dielectric sputtering system with non-grounded electrodes

An improved r.f. dielectric sputtering system is reported in which sputtering from grounded metal components is avoided by using two insulated lead-ins connecting the r.f. power supply to two metal electrodes backing the dielectric target. One form of the system described consists of a dielectric disk backed by a central disk and an annular electrode. A magnetic field is used to increase the ionization probability and confine the plasma produced by the r.f. electric field; a separate ionizing source is not used. Results are given for the deposition rate of silica sputtered in argon as a function of r.f. power input and for the film thickness distribution over the work area. Using a silica disk of 20·3 cm diameter with a substrate-to-target distance of 3·2 cm, films could be deposited at a rate of 700 Å min −1 in commercial argon at 4 mtorr pressure. Film thickness uniformity to better than ±5% could be obtained over an area of 200 cm 2 .