The ATC Series Thin Film Deposition Systems can be configured for con-focal, direct, and off-axis deposition. Con-focal deposition with in-situ tilt sputter sources (AJA pioneered and developed this concept in 1991) can deliver uniformity of better than +/- 2% on substrates twice the diameter of the targets. Often +/- 1% or better is achievable. A typical deposition profile with SiO2 on a 6" diameter Si wafer is shown. Deposition rate is a function of sputter yield of the material, maximum allowable power density into the target (depends on heat transfer capability of target material), and type of power used (e.g. RF, DC, pulsed DC). Maximum deposition rates are achieved with materials such as Au - high sputter yield, excellent heat transfer material and can be sputtered with DC (most efficient). Slow deposition rates can be expected with materials such as Al2O3 - very low sputter yield, poor heat transfer material and must be sputtered with RF (1/2 the efficiency of DC). Typical rates are 0-18 Å/sec with Au, 0-9 Å/sec with Cu and 0-0.16 Å/sec with Al2O3 in a confocal configuration with 2" sources on a 100 mm diameter substrate. Off-axis deposition rates are typically 1-5 times lower than con-focal deposition rates depending on substrate size and system configuration. Direct deposition at short working distances (50-100 mm) can achieve rates as high as 300 Å/sec but con-focal geometry results in much better uniformity, the ability to co-deposit alloy films and the ability to grow better ultra-thin film multilayers since the substrate is always "in the plasma." The cost of the smaller targets employed in con-focal configurations can also significantly reduce operating cost. The ultimate system configuration offered will always depend on the application.
