Effect of decomposition and organic residues on resistivity of copper films fabricated via low-temperature sintering of complex particle mixed dispersions

Abstract

Mixtures of a copper complex and copper fine particles as copper-based metal-organic decomposition (MOD) dispersions have been demonstrated to be effective for low-temperature sintering of conductive copper film. However, the copper particle size effect on decomposition process of the dispersion during heating and the effect of organic residues on the resistivity have not been studied. In this study, the decomposition process of dispersions containing mixtures of a copper complex and copper particles with various sizes was studied. The effect of organic residues on the resistivity was also studied using thermogravimetric analysis. In addition, the choice of copper salts in the copper complex was also discussed. In this work, a low-resistivity sintered copper film (7 × 10−6 Ω·m) at a temperature as low as 100 °C was achieved without using any reductive gas.

Ambient Aqueous-Phase Synthesis of Copper Nanoparticles and Nanopastes with Low-Temperature Sintering and Ultra-High Bonding Abilities

“…Yonezawa et al . reported that a small amount of low-molecular-weight gelatin on a Cu 2 O layer on the surface of copper NPs prevented further oxidation of the copper NPs 36 . Based on our results, the NTA on the surface of the copper NPs also prevents oxidation of the copper NPs in the present study.

Figure 1Crystal structure analysis and morphological observation of copper NPs.

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“…Therefore, studies utilizing inexpensive copper as nanoinks for circuit-forming materials and bonding materials instead of silver nanoparticles have expanded 30–34 because the thermal conductivity of bulk copper is 398 W·m −1 ·K −1 . To date, various methods, such as hydrazine reduction 2,35,36 , polyol reduction 37–41 , thermal decomposition 42 , and electrochemical reduction 30 , have been proposed for the synthesis of copper nanoparticles (NPs) with low-temperature sintering ability. Despite extensive efforts by researchers, the above-mentioned methods require the use of polymers and surfactants to control the diameter of copper NPs and prevent aggregation in organic solvents.…”

Recent Development of Joining and Conductive Materials for Electronic Components

“…As for other methods, it has been reported that by sintering a mixture of copper particles and copper-based metal-organic decomposition ink, a highly conductive sintered copper film could be obtained at a sintering temperature of 100°C. 88,89)…”

Filtration-induced production of conductive/robust Cu films on cellulose paper by low-temperature sintering in air

“…H 2 or vaporized formic acid) or inert gas (e.g. N 2 ) to produce the conductive patterns because the air-thermal sintering process of Cu-based inks tends to oxidize the copper [12–32]. The development of air-sintered Cu-based inks compatible with quick and effective roll-to-roll processes in printable electronics would represent a substantial advancement.…”