Fabrication of Poly(tetrafluoroethylene) Microparts by High-Energy X-ray-Induced Etching

Abstract

The development of thin-film electronic and magnetic properties with film sire are addressed in a study of Fe on Au(WI), up to 10 Fe layers thick and including the Au averlayer formed during normal growth conditions. Enhanced moments at the FeIAu interfa+e are observed. decaying to bulk over 3 Fe layers. and the weak F e A u inferaction is reflected i0 moments similar lo those of the Fe(W1) surface and in a very small asymmeuy i n the magnetic properties of the Fe film. Calculated hyperfine fields are found to exhibit a smng dependence upon film thickness and no simple relationship with the local spin moments. Densities of states and core-level shifts reflect changes in nearest-neighbour spsies and give a consistent p i c m of the interface bonding. The development of zone-centre states with film thickness is followed. and bulk-band overlap and interfacial bonding are found to influence h e disuibulion of quanhun well states sbongly.

Rapid X-ray Fabrication of Microstructured Polytetrafluoroethylene Substrates by Anisotropic, Pyrochemical Microetching

“…We developed a membrane-free, Ni-electroformed, stencil mask that was 200-m thick using conventional X-ray lithography using SU-8. [5,6,[14][15][16] The 400-m-thick PTFE sheets were exposed to X-ray with dose 120 A • s/mm through the Ni-electroformed stencil mask at 1.5GeV. Optical photographs of the microfluidic device that were irradiated and heated at 150, 200, 250, and 300 � are shown in Fig.…”

“…The conventional SR-ablation process requires heating, and differences in the linear coefficients of expansion for the exposure stage, Xray mask and PTFE can cause pattern distortion. In our previous studies, [5,6] the lateral structure has been distorted, and its positioning has been misaligned. Recently, anisotropic, pyrochemical etching has been investigated by Yamaguchi et al [7] The etching mechanism was related to the scission of PTFE main chains by X-ray irradiation with high photon energies ranging from 4 to 12 keV.…”

“…Recently, it has been determined that synchrotron radiation (SR) can facilitate micron-scale etching of PTFE at a very rapid rate. [2][3][4][5][6][7] Recently, several studies have reported on the microetching of PTFE substrates using SR irradiation. Zhang et al [2] have demonstrated the direct microetching of PTFE substrates with a high aspect ratio using an SR-induced ablation reaction.…”

“…Nagai et al [4] have reported that the photons with energies ~100 eV contributed to the efficient decomposition of PTFE through SRinduced reactions; fluorine absorbed the SR, resulting in ablation of the PTFE. Ukita et al [5] and Kido et al [6] have revealed that higher photon energies induced the scission of the PTFE main chain, C-C bond, enabling the ablation of the PTFE substrate without residual carbon dross. They have also observed that microetching conducted at higher X-ray photon energies was able to proceed without changing the stoichiometry of the PTFE.…”

“…They have also observed that microetching conducted at higher X-ray photon energies was able to proceed without changing the stoichiometry of the PTFE. [5,6] Thus, the etching of PTFE by SR has been qualitatively reported and can be used to produce microstructure for engineering applications such as filters and microfluidic devices.…”