Improved Photolithography Techniques for Electronic Circuitry of the Future

Fabrication of nanometer scale patterns with polymer Langmuir-Blodgett films

Modern electronics demand constant improvements in power and speed. Consequently, the circuitry becomes increasingly complex with a trend to higher circuit density. In order to fabricate circuits at these higher densities, research efforts have focused on varieties of high-resolution lithography techniques. These techniques have included electron beam (EB), X-ray, and deep UV irradiation. A new approach is the use of ultra-thin films and new materials.

The Langmuir-Blodgett (LB) technique is very effective method used to prepare well-defined ultra-thin films with controlled thickness and orientation at a molecular level. Due to these properties, LB films are expected to result in ultra-high resolution photolithography.

In a paper published in AZojomo*, researchers Tiesheng Li, Masaya Mitsuishi and Tokuji Miyashita, from Zhengzhou University and Tohoku University, investigated the photolithographic properties of poly(N-tetradecylmethacryl-amide-co-t-butyl 4-vinylphenyl carbonate) [p(TDMA-tBVPC)] thin films prepared using the Langmuir-Blodgett (LB) technique.

They were able to create a stable monolayer copolymer that showed positive tone patterns after irradiation with deep UV light and development with an alkaline aqueous solution. The resolution of the etched pattern was 0.75 µm, which is the resolution limit of the photomask employed.

Results indicated that the films were suitable for use in lithographic processes in the future.

The article is available to view at

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