Intensive Plasmonic Flash Light Sintering of Copper Nanoinks Using a Band-Pass Light Filter for Highly Electrically Conductive Electrodes in Printed Electronics

Abstract

In this work, an intensive plasmonic flash light sintering technique was developed by using a band-pass light filter matching the plasmonic wavelength of the copper nanoparticles. The sintering characteristics, such as resistivity and microstructure, of the copper nanoink films were studied as a function of the range of the wavelength employed in the flash white light sintering. The flash white light irradiation conditions (e.g., wavelength range, irradiation energy, pulse number, on-time, and off-time) were optimized to obtain a high conductivity of the copper nanoink films without causing damage to the polyimide substrate. The wavelength range corresponding to the plasmonic wavelength of the copper nanoparticles could efficiently sinter the copper nanoink and enhance its conductivity. Ultimately, the sintered copper nanoink films under optimal light sintering conditions showed the lowest resistivity (6.97 μΩ·cm), which was only 4.1 times higher than that of bulk copper films (1.68 μΩ·cm).

Copper micro-electrode fabrication using laser printing and laser sintering processes for on-chip antennas on flexible integrated circuits

“…Upon laser irradiation, the copper oxide is reduced to copper and the nanoparticles are subsequently sintered during a short period of time (laser pulse duration is about 100 ns). The reduction of Cu 2 O to Cu has also been observed by Dharmadasa et al [47] and Hwang et al [21], who used intense pulse light to sinter Cu/Cu 2 O nanoinks.…”

“…Unfortunately, the majority of flexible substrates, which are thermoplastics like PEN or PET, have low glass transition and melting temperatures and consequently they can't be exposed to temperatures in the order of 200-300°C in a furnace. Thus, alternative methods of sintering had to be employed in order to fabricate conductive patterns, such as chemical [17] and photonic sintering [18][19][20][21][22][23][24][25][26][27][28][29][30].…”

“…Flash light sintering can cover a very large area of the printed substrate with a single pulse, offering no lateral selectivity and the resulting heat affected zone might be extended. Flash light sintering of copper nanoparticle inks has been studied thoroughly in the last decade [18][19][20][21][22][23], with the best resistivity value (5 µΩ•cm), achieved from H-S. Kim et al [23], in 2009. On the other hand, laser pulses are spatially confined in a small area, and the sintering process is performed by scanning the laser beam over the printed pattern.…”

Metallic Nanoparticle Inks for 3D Printing of Electronics

“…Hence, it can be • Melting point: 1234.93 K [26] • Excellent electrical conductivity, thermal conductivity, and oxidation stability [21,27,28] • Unique optical, plasmonic, and antibacterial properties [21,54] • Tunable optical, electrical, and chemical properties [55] • Exhibits surface plasmon resonance (SPR) effects [5,50] • Patch antennas [51] • 3D antennas [52] • RFID tags [53] • Thermal sintering [48,49,157] • Laser sintering [158] • Intense pulse light (IPL) sintering [57,58] • Infrared (IR) sintering [159] • Ultraviolet (UV) sintering [59] • Microwave sintering [160] • Plasma sintering [161] • Electrical sintering [162] • Sintering temperatures ranging from 100 to 300 °C [31,48,49,157] • 3 µΩ cm after 10 min of thermal sintering at 200 °C (UTDAgTE) [157] • 8 µΩ cm after 60 min of thermal sintering at 140 Although they are highly suitable for formulating highly conductive metallic nanoparticle inks, their melting temperatures are considerably high also.…”

Use of decomposable polymer-coated submicron Cu particles with effective additive for production of highly conductive Cu films at low sintering temperature

“…19 Laser processes, however, are complex, low throughput, and associated with considerable environmental challenges. 23 Other methods have been studied for low temperature sintering such as photonic sintering of copper particles by Oh et al 22 A low resistivity of 6-7 Â 10 À8 O m was achieved using photonic sintering at 2.5 kV for 1.5-2.0 ms. The substrate temperatures using such voltage were less than 110 1C.…”