Organic-Inorganic Composite Resists

Contrary to organic polymers, inorganic materials form products with very reduced, or no volatility when treated with an oxygen plasma. Therefore, their removal takes place via sputtering processes only. 

Another approach reported the use of fullerene Cgo films as e-beam resist. The irradiation of a Cgo film was found to reduce the dissolution rate in organic solvents. Furthermore, the inorganic films have higher dry etch resistance compared to conventional Novolac resists. 

Employing composites of organic and inorganic components represents a novel trend in the design of resists. In order to accommodate the fabrication of small features, at least one of the components needs to be structured on a nanoscale level. The bottleneck for preparing such nanocomposites lies in the tailoring of the surface and interfaces of the components, such that a homogeneous dispersion is obtained. 

Approaches involving nanocomposite resists benefit from higher softening temperatures and increased rigidity, thereby reducing the probability of pattern collapse. Furthermore, increased etch resistance is also warranted. 

The plasma etch rates of nanocomposites, consisting of PMMA resists, impregnated with Ceo fullerenes, were compared with those of commercially available resists. Fullerenes were found to be successful at improving the etch resistance under CF4 and CI2 reactive ion etch conditions. The basic idea of this concept is the reduction of free volume in the polymer resist film. This then results in improved mechanical and etch resistance. 

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Hou L., Menning M., Schmidt H., Improvement of photofatigue resistance of spirooxazine entrapped in organic-inorganic composite synthesized via sol-gel process, SPIE Proc. 2288, 328-339, (1994). 

All acidic proton conductors discussed so far in this review have relied on the presence of large amounts of water (A = 10—30) as a mobile phase for the conduction of protons. Current targets for automotive use of hydrogen/air fuel cells are 120 °C and 50% or lower relative humidity. Under these conditions, the conductivity of the membrane decreases due to low water uptake at 50% relative humidity and thus creates large resistive losses in the cell. To meet the needs of advanced fuel cell systems, membranes will have to function without large amounts of absorbed water. Organic—inorganic composites are one preferred approach. ... 

Reinforced polymers with inorganic fillers are known to show greater resistance to radiation than original polymers. Most of organic materials in fusion reactors must be designed to employ organic-matrix composites as it appears very doubtful that conventional polymers can withstand the severe radiation environment for a reasonably long operation time. 

The most important methods for preventing atmospheric corrosion are 1) to select a corrosion-resistant structural material, 2) to use a corrosion-resistant coating (metallic, inorganic, organic or composite), and 3) to close internal cavities in order to avoid access of humid air, or conversely, 4) to make sure that there is ample ventilation and drainage, and possibly 5) to supply oil, grease, or special substances such as tectyle to the cavities. 

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