Product: Optically transparent, electrically insulating, ferromagnetic thin film layers synthesized through our processing technology.
The subsidiary minima in the XRD pattern is an indication of a very high crystalline quality of the film.
Also worth to note is the magnetization value. Ferrimagnetic YIG is less versatile and has significantly lower magnetization value. Even significantly higher magnetization values are achievable by appropriate synthesis. Coercive field values can be increased.
We do not do evolutionary changes to the existing state of practice but rethink the problem solving.
Validated features
- Excellent reproducibility (see [Note 1])
- Semiconductor industry compatible - the benefits of magnetic thin films and semiconductor processing can be exploited - thin film devices can be integrated directly on the chip (i.e. no surface mounting)
- Mass-production compatible processing technology - layers can be deposited using common, standard industrial technologies
- Electrical conductivity and magnetization can be tuned and precisely controlled - an advantage for device manufacturing
- Functional up to and including elevated temperatures
Patterning tool built at Oak Ridge National Laboratory and direct patterning successfully performed - demo video available
- Our materials enable mass production of electronic devices by room-temperature resettable direct-patterning (see [Note 2])
- The materials enable critically simplified patterning (see [Note 3]):
- There is no need for complex tools or pre-processing of the film. In current lithography technologies, the problems are related to the resist layer (photoresist, photoelectron resist, resin).
- There is no need for complex tools or pre-processing of the film. In current lithography technologies, the problems are related to the resist layer (photoresist, photoelectron resist, resin).
[Note 1] It should be emphasized that the technology is not based on the phase-change materials. We took a different approach from the beginning to avoid known problems. It is critical to choose an appropriate material design approach at the outset, as a poor choice will result in poor fabrication reproducibility, device scaling and time-dependent properties.
[Note 2] For comparison, our pattern technology is much simpler than direct writing via electron beam (EB) lithography, which is sometimes classified as a direct writing technology. However, EB lithography relies on the use of a resist layer that is scanned by an electron beam. As such, it suffers from the same problems as traditional photolithography, and a more appropriate term is mask-less patterning. Scanning is slow and throughput is low, making EB technology unsuitable for mass production. Unlike EB technology, our patterning technology is scalable and the patterned film can be reset.
[Note 3] Although nanoimprint lithography (NIL) is sometimes referred to as a revolutionary lithographic technology, it is a complex technique for simple device manufacturing. NIL shares the same fundamental problems as traditional UV-lithography due to the use of a resin layer, and also has problems that are specific to NIL. In NIL, the nanopattern mask (mold) is transferred to the coated resin on the wafer surface to form a desired pattern. The mask, typically manufactured by EB lithography, is in contact with the resin, leading to many reliability issues. The pattern formed is certainly not reversible, and typically NIL requires etching. A common argument in favor of NIL over traditional lithography is the lower manufacturing cost. Additional steps such as electrode material deposition or ion implantation are still required to create devices. Similarly to UV-lithography, the use of a resin layer not only increases the complexity and cost of the process, but is also the source of defects after mask transfer (e.g. proximity effects) and subsequent removal of the mask and residual resin layer. For complex circuit manufacturing, NIL is unnecessarily complex and error prone, there are better ways.
Right-hand side flowchart: Re-writable direct-writing technology - a feasible, technologically better and cost-effective alternative for the traditional route, shown on the left-hand side flowchart.
Without compromising the environment, the materials and processing technologies developed at RE provide a path to more efficient and significantly smaller electronics.
- No need for toxic chemicals, rare earths, iron, palladium, heavy metals or ultra-pure water
Compatibility with Integrated Circuit Manufacturing Technology
While it is the novel thin film layer(s) into which the devices are created (so our technology is not tied to any specific wafer materials), we have maintained compatibility with the major industrial materials.
- Validated compatibility with wide band gap semiconductors Gallium Nitride (GaN), Aluminum Nitride (AlN), Silicon Carbide (SiC) and Silicon (Si) allows magnetic thin films to be combined with today's semiconductor technologies
- High thermal conductivity wafers, sapphire (Al2O3) and piezoelectric substrates (lithium niobate, LiNbO3, lithium tantalate, LiTaO3 and a-quartz, SiO2) are validated platforms for our material
- Compatibility with the piezoelectric materials enables effective use of magnetic films in MEMS-devices
- Magnetic films are suitable for microwave devices, magnetic field sensors and magneto-optic applications. Low-permeability conductors can also be fabricated
Miniaturization
Our material is the key to a proven disruptive technology for patterning devices on wafers. Although the films can be patterned by standard lithographic techniques, they enable a disruptive, validated direct-patterning technology.
- Laser processing, including UV-lasers, can be used
- Absorption of as-grown films is strong at wavelengths λ < 300nm. The minimum line width (W) is determined by λ, numerical aperture NA of the optics and k (a manufacturing dependent factor, ≥ 0.25):
W = k λ / NA
- Short λ implies high resolution, and strong ultraviolet light absorption means the films are suitable for efficient patterning
The processing technology enables very fast and cost-effective patterning — such as electrodes, resistors, capacitors, waveguides, isolators, circulators, phase shifters, delay lines — on a film. Both high- and -low permeability materials can be produced.
No expensive lithographic equipment, photoresists, etching, toxic chemicals
The lithographic equipment industry is dominated by a few gigantic corporations. Traditional R&D&I is an option available only to large corporations (semiconductor foundries and a handful of governmental sites requiring significant funding). Monopolization and high production costs are associated with geopolitical risks. Moreover, R&D&I and manufacturing through the traditional route is a slow, irreversible process.
Our patterning process does not require:
- Photoresists, Developers, Etching, Fluorine Gas (commonly used to remove the oxide film from areas that are not covered by the photoresist layer)
- Materials added
- Ion implantation
- We are creating conductive and insulating regions in an easier way than ever before
Today's lithography chemistry is complex and expensive: changes in wavelength require corresponding changes in the entire manufacturing chain - instrumentation, photoresists, etching, ...
In contrast, direct patterning allows for a much simpler process and therefore drastically reduces energy consumption. This means an order of magnitude cost savings in manufacturing — centralized foundry production means long lead times, huge costs, and customer prioritization.
EMI protection
Protective layers against electromagnetic Interference (EMI) can be easily fabricated in-situ on circuits using high-permeability materials.
- Shielding structures can consist of single or multiple layers with adjustable conduction, permeability and magnetization levels
- Lattice matched, low-surface-roughness oxide layers can be grown on top of the EMI-shielding structures, allowing additional devices to be patterned on top of the stack
- Layers can be grown in a preferred crystallographic orientation by a suitable fabrication process
- The directly written conductors are embedded by the nature of the process, significantly reducing EMI
Fast and feasible manufacturing of integrated devices without geopolitical issues and export restrictions
Those affected by the chip shortage benefit from re-writable (reusable) platforms. Examples include automotive and Monolithic Microwave Integrated Circuit (MMIC) manufacturers.
- Thin film devices: Frequency filters required by 5G and beyond technologies, isolators, circulators, resistors, inductors, delay lines and phase shifters can be manufactured and tested in-situ much faster and at dramatically lower costs.
We offer a long-term solution by providing the technology for distributed manufacturing enabling chip design and production to be done locally — in stark contrast to the gigantic foundries that currently monopolizing chip production. As the Covid-pandemic has shown, monopolies prioritize customers and are difficult to work with.
Chip shortage hits the industry and reveals the caveats of centralized foundry production
Defying Rock's law
According to Rock's law (also known as Moore's second law), the cost of a semiconductor fab doubles every four years.
In contrast, we provide affordable and versatile thin-film platform for simple, very low-cost manufacturing for high-volume production and prototyping of micro- and nano-scale devices.
We do this through technologically advantageous thin-film materials that can be patterned without the need for photoresists, developers, etching and associated expensive instrumentation.