Y. Nakajima
K. Obata
M. Machida
J. Koch
O. Suttmann
M. Terakawa

Fabrication of silver/PDMS composite microstructures by using femtosecond laser

International Symposium on Laser Precision Microfabrication (LPM)
5.-8. Juni
Toyama
2017
Type: Konferenzbeitrag
Abstract
Femtosecond laser direct writing by multiphoton absorption enables precise fabrication of three-dimensional micro/nano structures. The fabrication method of femtosecond laser direct writing can be categorized to those based on photoreduction of metal ions [1] or on photopolymerization [2]. Recently, fabrication of metal/polymer composite structures using simultaneous induction of photoreduction and photopolymerization has been reported for applications in flexible electronics and MEMS, in which flexible polymeric matrix containing metal can exhibit electrical conductivity and plasmonic optical properties [3-5]. In this study, we attempted the fabrication of a polydimethylsiloxane (PDMS)/metal composite micro structure by the simultaneous induction of photoreduction and photopolymerization. Femtosecond laser pulses at 522 nm wavelength were irradiated onto a mixture of photocurable PDMS and silver benzoate in hexane (20 mg/ml) deposited on a cover glass. The laser pulses were focused with an objective lens (NA = 0.4). Fabricated structures were observed with an optical microscope after removal of the unsolidified portion. Figure 1 shows optical microscope images of a structure fabricated with laser scanning. The laser power and the scanning speed were 80 mW and 3 mm/s, respectively. A line structure with a line width of {\~}20 μm was formed along the scanning direction (Fig. 1 (a)). As shown in Fig. 1(b), a magnified image of the dashed square in Fig. 1(a), translucent and turbid structures were distributed randomly inside the line structure. Elemental analyses of the fabricated structure will be also presented.