Direct Intense Pulsed Light Sintering of Inkjet-Printed Copper Oxide Layers within Six Milliseconds

Abstract

We demonstrate intense pulsed light (IPL) sintering of inkjet-printed CuO layers on a primer-coated porous PET substrate to convert the electrically insulating CuO into conductive Cu. With this approach, conductive layers are obtained in less than 1 s after the printing process. The IPL sintering was performed for high productivity with minimum duration and repetition of IPL irradiation to evaluate the effect of pulse number and energy output on the conductivity and morphology of the sintered Cu layers. Depending on the energy output, sheet resistances were measured as 0.355, 0.131, and 0.121 Ω·□(-1) by exposure energy of 5.48 (single pulse), 7.03 (double pulse), and 7.48 J·cm(-2) (triple pulse), respectively. In contrast, an excessive energy with relatively short pulse duration causes a delamination of the Cu layer. The lowest resistivity of about 55.4 nΩ·m (corresponds to about 30% conductivity of bulk Cu) was obtained by an IPL sintering process of 0.26 s after the printing, which was composed of 2 ms triple pulses with 10 Hz frequency.

Inkjet Fabrication of Copper Patterns for Flexible Electronics: Using Paper with Active Precoatings

“…This is consistent with previous observations by Kang et al 27 , who noted crack formation along the printing direction.…”

“…Other interesting studies were performed by Hwang et al 25 One of the most promising methods of Cu film fabrication is the IPL processing of CuO NPs. [27][28] CuO NPs are less reactive in dispersion than the CuNP counterpart, and stable water-based inks have been made commercially available. Further, CuO NP inks can be acquired commercially at much lower cost (currently 75$/kg in bulk quantities 29 ) than CuNP-or AgNP inks.…”

Pulsed light sintering of silver nanoparticles for large deformation of printed stretchable electronics

“…Beyond these intensity and duration levels, samples quickly degraded due to the over-sintering that causes circuit disconnection failure. These findings are in line with previous research with other materials [35], where the optimal parameters deliver enough energy to thoroughly sinter the particles without damaging the substrates or nanoinks for excessive expoa b c d e f Fig. 2 Sample preparation was as follows: a PDMS was mixed and poured into molds and allowed to cure; b Ag ink was printed onto the samples and allowed to cure; c the test circuits were then sintered using the IPL device; d a Cu tape was applied to the contact pads; e samples were over-coated by a layer of PDMS and allowed to cure; and f leaving the flexible test circuit embedded in the PDMS sample Table 2 IPL parameter sensitivity study on the Ag strips (2 mm × 30 mm).…”

Development of hybrid process for double-side flexible printed circuit boards using roll-to-roll gravure printing, via-hole printing, and electroless plating

“…7c. However, after Cu plating, the Cu particles cover the Ag flakes and fill the pores [30] between the Ag particles to afford good conductivity, as shown in Fig. 7d.…”

“…Such systems are called hybrid processes, and integration of the printing methods is necessary to maximize the efficiency of the products [27,28]. Furthermore, it is necessary to adopt the Cu plating process to improve the electrical performance of a FPCB in the presence of Ag material limitations [29,30].…”