The Levitrack™ ALD system is based on the innovative concept of precursor separation in space, as opposed to time, in combination with the unique floating wafer and conductive heating technology used in the Levitor RTP products.
In the system, substrates float in a linear gas track and are heated to the required process temperature (below 300°C) within a matter of seconds. At process temperature, the substrates glide without contact through a series of ALD deposition cells. Each cell consists of two precursors, which are separated in space by a nitrogen purge (acting as inert gas curtains).
A sequence of precursor 1/nitrogen purge/precursor 2/nitrogen purge results in the deposition of 1 monolayer. The number of active ALD deposition cells depends on the required layer thickness.
The combination of a relatively large purge gas flow and a narrow gap between the substrate and the gas divider block ensures a very effective separation of the precursors, which is vital as mixing of precursors will result in CVD growth of particles.
The unique design of ALD deposition cells technology even allows for single-side ALD growth, as one side of the gas track can run with nitrogen. As each ALD deposition cell is optimized for a fast linear motion of the substrates, high throughput is guaranteed.
- High throughput, due to precursor separation in space
- No deposition of films on the wall of the track
- No deposition on the back side of the wafer
- No vacuum pumps (the entire track operates at 1 atmosphere)
- Low cost construction materials; with a deposition temperature < 300°C, the entire track can be constructed from aluminium
- Because of the narrow gap, heating of the wafer is fast