Vortex Rotary Batch ALD by Lotus Applied Technology
Lotus Applied Technology’s Vortex ALD technology revolutionizes batch ALD processing. Instead of pulsing and purging precursors from a static substrate in a single chamber, the substrate is transported by rotation to the various precursor and purge zones of the reactor, eliminating the time required for precursor introduction, saturation, and purge with each ALD cycle. Further, Lotus’ patented Radical Enabled ALD process, incorporating Precursor “Separation” by Radical Deactivation technology, greatly simplifies zone separation in the reactor, and enables the use of a simple DC plasma for PEALD processing.
Operating under medium vacuum conditions of about 1 Torr pressure, the purge gas sweeps from the center of the reactor, where oxygen radicals are generated, to the sides, where precursors are introduced and pumping is applied. The annular region of the substrate platen which passes directly under the plasma electrode is the only surface inside the reactor that gets coated, as it is the only surface which is exposed to both the precursors and the plasma. No deposition occurs on the plasma electrodes or on any other surface above the plane of the substrates.
Unlike systems designed for deposition at atmospheric pressure, gas zone separation is easily maintained even with large openings between the center purge region and precursor regions. This allows processing of relatively thick and irregularly shaped substrates such as optical lenses, or implantable medical devices for example. It also enables scaling the process to conventional drum coating configurations, where very large batches of small parts may be coated at high speeds. The plasma process allows low temperature deposition of a wide variety of materials, including SiO2, TiO2, Ta2O5, ZnO, HfO2, ZrO2, at batch coating speeds over 5 Å/second, while preserving the unique high quality attributes of ALD coatings.
SiO2 Deposited using Vortex Rotary ALD
Lotus’ Vortex Rotary ALD offers many advantages, including:
- Batch deposition speeds of several angstroms per second – faster than many oxide sputtering processes
- Low particulate generation – no coating anywhere in the chamber except on the substrates and carrier surface
- Low materials costs – precursors are consumed only on the substrate track – exhausted precursor material may be captured and re-used
- Low temperature processing using simple DC plasma
- All the advantages of ALD coatings
- Extremely high conformality
- High film density with low film stress
- Pinhole-free coatings
- Outstanding uniformity and repeatability
- Great tolerance to variability of process conditions
To learn more about our Vortex Batch ALD technology, please read our White Paper: Vortex ALD by Lotus