Aryltriazene photopolymer thin films as sacrificial release layers for laser-assisted forward transfer systems: study of photoablative decomposition and transfer behavior

Abstract

Thin films of a tailor-made photodecomposible aryltriazene polymer were applied in a modified laserinduced forward transfer (LIFT) process as sacrificial release layers. The photopolymer film acts as an intermediate energy-absorbing dynamic release layer (DRL) that decomposes efficiently into small volatile fragments upon UV laser irradiation. A fast-expanding pressure jet is generated which is used to propel an overlying transfer material from the source target onto a receiver. This DRL-assisted laser direct-write process allows the precise deposition of intact material pixels with micrometer resolution and by single laser pulses. Triazene-based photopolymer DRL donor systems were studied to derive optimum conditions for film thickness and laser fluences necessary for a defined transfer process at the emission wavelength of a XeCl excimer laser (308 nm). Photoablation, surface detachment, delamination and transfer behavior of aryltriazene polymer films with a thickness from 25 nm to ∼400 nm were investigated in order to improve the process control parameters for the fabrication of functional thin-film devices of microdeposited heat-and UV-sensitive materials.

Improved laser-induced forward transfer of organic semiconductor thin films by reducing the environmental pressure and controlling the substrate–substrate gap width

“…From front-side-ablation studies, it is known that around 80 mJ/cm 2 is required to fully ablate 190 nm TP [28,29]. This means that the triazene may not be completely decomposed until a fluence of up to 80 mJ/cm 2 , and possibly even above it.…”

“…The circular patterns appear to be located in the same places of the pixel, irrespective of the sample and pressure. Without additional research it is hard to interpret these patterns, but similar oscillatory patterns have been observed in front-side ablation of triazene before [27,28].…”

Laser-induced transfer of nanoparticles for gas-phase analysis

“…An alternative method for transferring nanoparticles into vacuum is matrix-assisted pulsed laser evaporation (MAPLE), which is based on the use of a highly absorbing, easily vaporized matrix (usually a polymer) that serves as a solvent for the analyte particles and, being vaporized, carries the analyte toward a detector [5,6]. Another laserbased method, laser-induced forward transfer (LIFT), is a noncontact, single-step, direct-write technique which employs pulsed laser radiation penetrating a transparent substrate to heat and vaporize a donor film deposited on it [7][8][9][10][11]. The transferred material is either spread on the film [9] or introduced into a matrix [10,11].…”

Laser direct write printing of sensitive and robust light emitting organic molecules

“…Common realizations of LDW printing consist of direct matrix absorption ͑DMA͒, 6-8 thin metal film absorptive ͑MFA͒ layer, [9][10][11][12] and thin or thick polymer film absorptive ͑PFA͒ layer. [13][14][15] The DMA approach employs volatile and laser-absorbing solvents that decompose under pulsed illumination, resulting in volatile by-products that eject the remaining ink from the sacrificial substrate. 16 It is argued that the nonabsorbing solute is unaffected by the laser process, thus permitting the deposition of inorganic and organic materials.…”

“…This allows vaporization and subsequent material transfer at low incident fluences. 13,14,20,21 In contrast, thick film polyimide absorbing layer transfers exploit the photophysical and mechanical properties of the film by keeping it intact during the entire transfer process. 15 The polymer undergoes rapid plastic deformation thereby imparting momentum to the overlaying ink layer.…”