Synthesis and Formation Mechanism of All-Organic Block Copolymer-Directed Templating of Laser-Induced Crystalline Silicon Nanostructures.

This report describes the generation of three-dimensional (3D) crystalline silicon continuous network nanostructures by coupling all-organic block copolymer self-assembly-directed resin templates with low-temperature silicon chemical vapor deposition and pulsed excimer laser annealing. Organic 3D mesoporous continuous-network resin templates were synthesized from the all-organic self-assembly of an ABC triblock terpolymer and resorcinol-formaldehyde resols. Nanosecond pulsed excimer laser irradiation induced the transient melt transformation of amorphous silicon precursors backfilled in the organic template into complementary 3D mesoporous crystalline silicon nanostructures with high pattern fidelity.

Lateral Temperature-Gradient Method for High-Throughput Characterization of Material Processing by Millisecond Laser Annealing.

A high-throughput method for characterizing the temperature dependence of material properties following microsecond to millisecond thermal annealing, exploiting the temperature gradients created by a lateral gradient laser spike anneal (lgLSA), is presented. Laser scans generate spatial thermal gradients of up to 5 °C/μm with peak temperatures ranging from ambient to in excess of 1400 °C, limited only by laser power and materials thermal limits. Discrete spatial property measurements across the temperature gradient are then equivalent to independent measurements after varying temperature anneals.

POROUS MATERIALS. Transient laser heating induced hierarchical porous structures from block copolymer-directed self-assembly.

Development of rapid processes combining hierarchical self-assembly with mesoscopic shape control has remained a challenge. This is particularly true for high-surface-area porous materials essential for applications including separation and detection, catalysis, and energy conversion and storage. We introduce a simple and rapid laser writing method compatible with semiconductor processing technology to control three-dimensionally continuous hierarchically porous polymer network structures and shapes.

Laser-induced sub-millisecond heating reveals distinct tertiary ester cleavage reaction pathways in a photolithographic resist polymer.

Acid-catalyzed, thermally activated ester cleavage reactions are critical for lithographic patterning processes used in the semiconductor industry. The rates of these high-temperature reactions within polymer thin films are difficult to characterize because of the thermal instability of many polymers and a lack of temperature-resolved measurement techniques. Here we introduce the use of transient laser irradiation to heat a methyladamantane-protected acrylate copolymer to 600 °C in less than a millisecond.

Kinetic rates of thermal transformations and diffusion in polymer systems measured during sub-millisecond laser-induced heating.

Probing chemical reaction kinetics in the near-solid state (small molecules and polymers) is extremely challenging because of the restricted mobility of reactant species, the absence of suitable analytical probes, and most critically the limited temperature stability of the materials. By limiting temperature exposure to extremely short time frames (sub-millisecond), temperatures in excess of 800 °C can be accessed extending kinetic rate measurements many orders of magnitude. Here we demonstrate measurements on a model system, exploiting the advantages of thin-films, laser heating, and chemically amplified resists as an exquisite probe of chemical kinetic rates.