News Releases 2019Meiden developed groundbreaking technology for atomic layer deposition at room temperature
Meidensha Corporation (Meiden) has successfully established the world’s first technology1 for atomic-level film deposition that uses ozone-ethylene radical (OER) generation technology and a carrier gas for efficiently introducing precursors to create oxide layers at room temperature. The technology, called atomic layer deposition (ALD), has been developed jointly with the National Institute of Advanced Industrial Science and Technology. A related patent was submitted in February 2019.
ALD makes it possible to deposit layers on plastic films that are vulnerable to heat and mechanical stress. The deposited layers with less energy than conventional have extremely low water vapor permeability. The technology is expected to be applicable to broad range of areas, such as for encapsulating semiconductors and displays, and for surface conditioning of secondary battery components and auto parts.
The OER processing technology is proprietary to Meiden. This patented technology generates highly active hydroxyl (OH) radicals at room temperatures by reacting with high purity ozone gas– produced by our pure ozone generator – with ethylene gas. This technology makes it possible to reform, deposit films on and cleanse organic materials (non-metals). The success in higher density, room temperature ALD follows Meiden’s achievement of chemical vapor deposition2 (CVD) at room temperature in April 2018 using the OER processing technology.
During research and development, Meiden succeed in depositing a 40-nanometer-thick, single layer of aluminum oxide (AL₂O₃) with a high barrier property (6.5x10-5g/㎥/day)3 at room temperature. Meiden is currently working to improve the quality of both ALD and OER-CVD.
Meiden plans to develop and sell an OER processing device equipped with a pure ozone generator that would be capable of performing both CVD and ALD at room temperature using the latest technology.
1. According to a Meiden study
2. See press release from April 17, 2018.
3. The amount of moisture that permeates the film during 24 hours
《Conceptual diagram of OER-ALD process》
Film deposition occurs in a continuous cycle of ①＋②→①→③→① via carrier gas emission.
TMA: trimethyl aluminum gas, an oxide film precursor for making AL₂O₃ films. TMA is used mainly for ALD.
Merits of OER-ALD technology
– Reduced electric costs for film deposition because the process can be performed at room temperature, compared with conventional technologies that require substrate heating of 100℃ to 200℃.
– Film deposition can be performed on low-temperature materials without inflicting heat damage.
– Conventional ALD method required the vacuum evacuation of the chamber for every layer deposited for the separation of a precursor and an oxidizing source. The OER-ALD method complete gas shield between those gases by a proprietary shower head structure and a carrier gas flow, which shortens the time required for the vacuum evacuation.
– The OER technology uses a shower head for the gas flow that allows the user to choose between ALD or CVD by switching a controller. The thickness of layers deposited can be adjusted from a few nanometers to 1 micrometer.
– The OER technology can effectively radicalize precursor gas in the limited region around the processing substrate, which prevents unwanted deposition of byproducts at chamber wall.
《Conceptual drawings of conventional and new devices》
Conventional ALD method
OER-ALD method at room temperature (using the latest technology)
What is the pure ozone generator?
This device can continuously generate pure ozone gas (100% concentration). Meiden started developing the device in 2,000 and released it on the market in 2007. At present, semiconductor manufacturing equipment makers are the main buyers of the device, which can supply toxic and explosive ozone gas in a safe and stable manner.
Public Relations Division