Masakazu Uekita

Heat-stable aromatic polymer precursors as Langmuir-Blodgett film materials☆

Abstract New amphiphilic precursors of polyimide-isoindroquinazolinedione, polyamide-imide, polyimidazopyrrolone and polybenzoxadinone were synthesized. The monolayers of all the precursors on the water surface could be deposited onto various substrates by the Langmuir-Blodgett technique. Subsequent thermal treatment of the built-up films under a nitrogen stream successfully produced the corresponding polymer films, which show high heat stabilities over 300–500°C and good insulating properties.

Alignment of nematic liquid crystals by polyimide Langmuir-Blodgett films

Nematic liquid crystals with a high degree of alignment were prepared using polyimide (PI) Langmuir-Blodgett (LB) films. Polyimides with a linear primary structure are favorable for attaining highly oriented PI LB films. Furthermore, orientation of the PI LB films is essential in order to achieve well-aligned nematic liquid crystal molecules.

Effect Molecular Arrangement of Alignment Film for Liquid Crystals

We have studied the direction of liquid crystals on multilayer alignment films composed of Langmuir-Blodgett films deposited onto rubbed films. Depositing more than three layers of Langmuir-Blodgett film onto the rubbed films changed the direction of the liquid crystals. The arrangement of the surface molecules of the alignment film was found to determine the alignment of the liquid crystals, and the use of a molecular layer of 3 nm thickness resulted in the alignment of the liquid crystals.

Application of polyimide Langmuir-Blodgett films to deep UV resists

Abstract The preparation of Langmuir-Blodgett (LB) films based on a photosensitive polyimide precursor 2 and their application to deep UV resists have been studied. LB films fabricated from a mixed monolayer of polyimide precursor 2-octadecyl alcohol-benzoin ethylether (molar ratio, 3:3:1) were found to act as negative working resists with a resolution of 0.5 μm space and 1.0 μm line, a sensitivity of 100 mJ cm-2 and good plasma etching resistance. They are promising for application as KrF and ArF excimer laser resists corresponding to 16 and 64 Mbit dynamic random access memories.

Alignment of Nematic Liquid Crystal Using Polyimide Langmuir-Blodgett Films (II)

A new nonrubbed alignment film for nematic liquid crystals has been developed, which consists of a polyimide precursor Langmuir-Blodgett film with long alkyl groups. In addition, we have discovered that the pretilt angle of nematic liquid crystals can be controlled by changing the thermal treatment temperature of the polyimide precursor Langmuir-Blodgett films.

Low resistivity CdS(In) films prepared by spray pyrolysis

Abstract Low resistivity films of CdS doped with indium were prepared by spray pyrolysis. The resistivity was measured as a function of both the cadmium-to-sulfur molar ratio and the amount of hydroxylamine hydrochloride (NH 2 OH·HCl) added to the starting spray solution. The amount of indium was kept constant at 3 mol.%. For a Cd:S ratio of 1:0.9 the resistivity drops by about two orders of magnitude from 3400 to 16Ω cm as the NH 2 OH·HCl:Cd ratio is varied from 0 to 4. For Cd:S ratios of 1:1.2 and 1:1.5 the resistivity increases linearly for the same variation of NH 2 OH·HCl:Cd going from 1.5 to 8 Ω cm and from 0.68 to 6.8 Ω cm respectively. These results are discussed in terms of the Cd:S ratio in these systems.

Patterning of polyimide precursor Langmuir-Blodgett films and their application as deep UV resists

Abstract Polyimide precursor Langmuir-Blodgett (LB) films can be patterned by conventional photolithographic techniques utilizing deep UV light. The patterned polyimide precursor LB films can succesfully be converted to corresponding patterned polyimide films. Furthermore, these LB films are positive resists with a resolution of 0.4 μm and a sensitivity of around 3.5 J cm −2 . Patterned LB films with a thickness of only 80nm have good plasma etch resistance. This suggests that polyimide precursor LB films have potential for the fabrication of electronic devices with a feature size of less than half a micrometre, and might be a suitable resist for excimer laser lithography.