General Features Magnetic Field: Scanning 0-600rpm (servo). Target Size:          - Circular 5 - 20 inch (50 - 500mm).        - Rectangular Any Size, wider than 125mm. Target Fix: Clamped: indirectly cooled, see below. Magnet Array: NdFeB (not in water). Magnetic Strength: 200 - 600 over the target surface. Operating Range: 1-8 x 10-3mbar (>0.1 Pa). Ultimate Pressure: 10-8mbar (10-6Pa). Water Couplings: Target length dependant Cooling Water: 1 litres/min/kW - 3 bar max. No de-ionised water needed. Power Type: DC, RF, DC pulse, AC MFR. Power Connection: N-type, HN, 7/16" or direct to cathode.

The Full Face Erosion (FFE) source in circular and rectangular form offers very high target use, 45% - 60% due to the scanning nature of the magnetic field. Consequently there are no re-deposit areas on the target surface which aids the reactive deposition of compounds and also defect reduction. But that tells only part of the story! Researchers at MMU and Liverpool Universities in the UK at the SVC08 in Chicago illustrated a number of other startling benefits (see download for full presentation):

Elimination of the Hysteresis effect in reactive sputtering

Researchers at MMU working with a double rectangular FFE source and have discovered that as the speed of the scanning is increased to 300 rpm the usual hysteresis effect disappears and there is a linear transition of reactive gas partial pressure with flow in the TiO2 system.  As the plasma scans the target remains in a metallic state, and reactive  rates are not reduced as there is no target poisoning.

Smoother films with faster plasma scanning

The image to the right illustrates the effect on the coating roughness for the same TiO2 layer with increasing speed of scanning. The faster the scanning the smoother the film properties. The FFE magnetrons use a servo motor to control the speed and hence any speed can be selected. The magnetic scanning is brought about via simple spinning motion through rotary bearings, hence the speed can be very high and there are no vibration or wear issues for the parts. All the movement and the drive systems are at atmospheric pressure, hence there are no moving air to vacuum seals.

Tuning film structure by plasma scanning speed adjustment  A further startling result is the effect of rotation speed on the crystal structure of the TiO2 layers. Static sputter plasma's produce typically rutile TiO2 films under standard conditions. As the speed of rotation is increased the film crystal structure is transformed into a Anatase form at 200 rpm - see downloadable presentation. This gives the ability to tailor the film crystal structure purely through the scanning speed.

The FFE is a unique and powerfully tool for the high efficiency deposition of sputtered layers. It is capable of overcoming many of the traditional difficulties experienced when performing high rate reactive deposition. At the same time it improves the ecconomics of the production process by allowing easy to control fast process and tailored film properties.