Transfer by direct photo etching of poly(vinylidene flouride) using X-rays

Abstract

A direct pattern transfer method has been developed by photo etching poly(vinylidene fluoride) (PVDF) using X rays (1-16 keV) from a synchrotron storage ring. The ability to pattern thin film of PVDF, a piezoelectric, pyroelectric and ferroelectric polymer, has potential applications in the areas of MEMS, nonlinear optics, and nonvolatile ferroelectric random access memory technology. Without the use of any reactive chemical gas, a maximum etched depth in excess of 9 m is achieved. The etched depth for a given photon energy approaches saturation with respect to exposure time. An in situ mass spectrometry revealed the evolution of hydrogen, fluorine, and hydrogen fluoride species. The etched regions turned dark in color indicating a possible increase in the fraction of carbon atoms. The X-ray transmittance of photo etched PVDF approached that of a pure carbon as the exposure time is increased. Upon etching the root mean-square surface roughness of the etched portion increased by more than a factor of two. The rate of etching increased at elevated sample temperatures. [446]

Electronic structure and polymerization of a self-assembled monolayer with multiple arene rings

“…The white light beam provides broadband soft x-ray radiation ͑20-160 eV͒ centered around 70 eV, and where the integrated power is approximately 0.1 W at 100 mA of the ring current. [46][47][48] We find that nearly complete cross linking occurs by an exposure of 50 to 54 mC/ cm 2 of 50 eV electrons, or 500-600 mAmin of synchrotron white light. 19 The electron exposure threshold is consistent with an optimal dose of 40-45 mC/ cm 2 of 10 eV electrons found in previous studies.…”

Recent Developments in Polymer MEMS

“…These candidates include conductive polymers, [94,95] REVIEW www.advmat.de electroactive polymers [96] such as polypyrrole, [97][98][99] photopatternable gelatin, [100] shrinkable polystyrene film, [101] shape memory polymers, [102] and piezoelectric polymers such as polyvinylidene fluoride (PVDF). [103,104] Future work will require close collaboration between experts in the following three areas: device, microfabrication, and materials.…”

Laser-plasma extreme ultraviolet and soft X-ray sources based on a double stream gas puff target: interaction of the radiation pulses with matter

“…In case of the poly− mer irradiated with the low fluence the peak corresponding to binding energy 290.9 eV strongly decreased. It means that irradiation of PVDF with the low fluence results in carbon enrichment in the near−surface layer, similarly as in case of X−ray irradiation [33,34].…”

“…Micro− or even nanopatterning of PVDF is highly desirable for applica− tions in multifunctional and integrated devices. Many works have been performed on surface processing of PVDF using ion beams [31,32] synchrotron X−ray [33,34] and UV laser radiation [35,36]. Irradiation of PVDF with these sources resulted a in strong modification of the mo− lecular structure in a near−surface layer of the polymer leading to an increase of the ablation threshold.…”