Jeffrey R. Lancaster

Nonradiative Deactivation of Singlet Oxygen (1O2) by Cubane and Its Derivatives

The bimolecular quenching rate constants of singlet oxygen ((1)O2) by cubane and cubane derivatives were determined and found to be in the order of 10(3)-10(4) M(-1) s(-1). These values represent larger values than expected for aliphatic alkanes as a model for C-H vibrational deactivation. This result is explained by the occurrence of two different deactivation mechanisms: energy transfer to cubane C-H vibrational modes and the formation of a charge-transfer complex between (1)O2 and cubane ((1)O2(*-)...cubane(*+)).

1H NMR study of hydrogen abstraction in model compound mimics of polymers.

Small molecules representing common synthetic polymers were subjected to photochemically induced hydrogen abstraction by benzophenone. Reactions were monitored using 1H NMR to query the factors that influence preferential abstraction of protons in unique chemical environments. Differences in bond dissociation energies do not fully explain the observed hydrogen abstraction preferences. To that end, we identify contributions to abstraction from prereactive complexation, radical stability, steric effects and charge transfer effects. Using representative small molecule model compounds in lieu of polymeric materials is a novel approach to understanding photochemical reaction in polymers; however, it cannot probe the contributions of macromolecular effects—e.g. polymer rigidity or side chain and backbone mobility—to preferential hydrogen abstraction.

Electroless Deposition of Nickel on Photografted Polymeric Microscale Patterns

This report demonstrates the electroless deposition of Ni onto micropatterns of poly (acrylic acid) (PAA) photografted to phthalimide-terminated self-assembled monolayers (SAMs). PAA is spin-coated onto phthalimide SAMs and covered with a photomask. UV irradiation selectively binds PAA to exposed regions of the surface, allowing PAA on unexposed regions to be rinsed off. A Pd catalyst is then selectively adsorbed to regions of the surface where PAA is bound. The adsorbed catalyst selectively initiates Ni plating upon immersion of the substrate into a Ni(SO4 ) bath.

Adiabatic ring opening in tethered naphthalene and anthracene cycloadducts

The cycloadducts of tethered naphthalene and anthracene derivatives undergo photochemical ring opening to an electronically excited product with adiabatic yields up to 90%.

Fundamental study of optical threshold layer approach towards double exposure lithography

193 immersion lithography has reached its maximal achievable resolution. There are mainly two lithographic strategies that will enable continued increase in resolution. Those are being pursued in parallel. The first is extreme ultraviolet (EUV) lithography and the second is double patterning (exposure) lithography. EUV lithography is counted on to be available in 2013 time frame for 22 nm node. Unfortunately, this technology has suffered several delays due to fundamental problems with source power, mask infrastructure, metrology and overall reliability. The implementation of EUV lithography in the next five years is unlikely due to economic factors. Double patterning lithography (DPL) is a technology that has been implemented by the industry and has already shown the proof of concept for the 22nm node. This technique while expensive is the only current path forward for scaling with no fundamental showstoppers for the 32nm and 22nm nodes. Double exposure lithography (DEL) is being proposed as a cost mitigating approach to advanced lithography. Compared to DPL, DEL offers advantages in overlay and process time, thus reducing the cost-of-ownership (CoO). However, DEL requires new materials that have a non-linear photoresponse. So far, several approaches were proposed for double exposure lithography, from which Optical Threshold Layer (OTL) was found to give the best lithography performance according to the results of the simulation. This paper details the principle of the OTL approach. A photochromic polymer was designed and synthesized. The feasibility of the material for application of DEL was explored by a series of evaluations.

Looking back on Lindau

The Nobel Laureate Meetings held on the German island of Lindau bring together some of the worlds brightest young minds with those individuals who have reached a pinnacle of scientific achievement. The impact of this unique event on all the delegates — especially the young researchers — is far-reaching.