Conductive resists for nanofabrication on insulating substrates

Hasan, Farhan (2017). Conductive resists for nanofabrication on insulating substrates. University of Birmingham. Ph.D.

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Abstract

The purpose of this work is to support ongoing miniaturization of III-V microelectronic devices, which present a unique combination of economic and technical challenges. As miniaturization has proceeded photolithography has been able to meet required 20 nm feature sizes through the use of increasingly complex optical engineering techniques. However, this is not economically viable for low volume fabrication. The most promising low-volume technique here electron beam
lithography (EBL). However, on insulating substrates, (e.g. for III-V devices), charging during EBL leads to pattern distortion and resolution is limited. Whilst charge mitigation strategies exist, they introduce process complexity, and resolution limits.

A new approach using aconductive triphenylene electron beam resisthas been investigated. Triphenylenes form well-ordered hexagonal columnar discotic liquid crystals that show fast hole mobility (e.g. 10\(^-\)\(^3\) cm\(^2\)V\(^-\)\(^1\)s\(^-\)\(^1\)) along columns. The triphenylene based chemically amplified resist investigated here has a conductivity of ~10\(^-\)\(^6\) S/m at room temperature. It has demonstrated high sensitivity in EBL, requiring a patterning dose of ~14 μC/cm2on silicon and ~10 μC/cm\(^2\) on fused silica substrates at 50 keV exposure. The resist has demonstrated high-resolution patterning including 20 nm half pitch lines on silicon, and 55 nm isolated lines on glass at 30 keV exposure.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

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