Room temperature sintering mechanism of Ag nanoparticle paste

Abstract

Recently, the authors have developed a novel room temperature wiring method with Ag nanoparticle paste. In the present work, the sintering mechanism of Ag nanoparticle paste was clarified through analysis of the adsorption stability and the removal of the dispersant from the Ag nanoparticles. The Ag nanoparticles in the paste are protected by dodecylamine as a dispersant. This paste possesses a substantially long shelf life. When a printed line of Ag nanoparticle paste is dipped in a methanol bath, the methanol dissolves the dispersant allowing it to be removed from the nanoparticles, effectively. Ag nanoparticles are sintered within a short period, although the sintering is not uniform. Some Ag nanoparticles grow quickly and form networks by sintering necking. The other nanoparticles remain on the nano-meter scale. Large Ag particles and Ag skeletons continue to grow by absorbing very small nanoparticles. In addition, the effect of ethanol and isopropanol as treatment agents is found.

Improved Low Temperature Sinter Bonding Using Silver Nanocube Superlattices

“…Silver has an array of properties that can be tuned or enhanced through the control of nanoscale size and morphology for a variety of applications. − The field of nanowelding exploits the different thermal behaviors of nanosized particles compared to bulk materials, , which enables the formation of conductive metallic junctions at low temperature. − This is of high interest for the fabrication of electronic devices on flexible substrates and for power semiconductor devices. , It remains a challenge to produce junctions with excellent mechanical, thermal, and electrical properties after sintering at temperatures below 200 °C. The sintering process of nanoparticles is highly dependent on their surface characteristics. ,,, Many groups have examined the effects of size and surface coating sinter bonding using spherical nanoparticles. − It is now well-established that small silver nanoparticles undergo a rearrangement at temperatures well below their bulk melting point ( T m = 962 °C).…”

Isotropic conductive adhesives in electronics

“…Ye et al (1999) observed apparently sintered contacts of ~50nm diameter between Ag nanoparticles in an iCA, and similar contacts have been observed between micron-scaled ICA particles (Li and Morris, unpublished data, 1994). Sintering is clearly the key to the lower ICA resistivities appearing in the literature, and may explain the results of Yang et al (2008) by a 'room temperature sintering' process (Wakuda et al, 2008) of enhanced surface diffusion following removal of the protective surface layer.…”

“…Contact resistance reliability problems (Li et al, 1995;Liu et al, 1996;Botter et al, 1998) are primarily due to galvanic corrosion between dissimilar metals at the interfaces (Lu et al, 1999a,b; in the presence of water, with the resulting oxide leading to micro-crack failure (Kim et al, 2008). The resistance drift can be reduced or slowed by the addition of corrosion inhibitors, oxygen scavengers, and/or sacrificial anode material to the polymer matrix Wong, 1999a, 2000e;Takezawa et al, 2002), and moisture can be minimized with anhydridecured epoxies (Lu and Wong, 2000d).…”

Low-temperature silver sintering by colloidal approach

“…Transposed to sintering, this model allows to significantly reduce the sintering temperature using nanometer size particles to enhance sintering properties at LT. The strategy is particularly studied in the current development of nanosilver inks at room temperature [5,6]. They have attracted considerable interest as one of the most promising Ag-based conductive materials.…”

“…Such pastes typically include a solvent, an organic stabilizer and silver particles. The impacts of the nanocrystal size and surface chemistry on the sintering properties have been extensively studied [5,6]. Nanosilver pastes can be sintered at lower temperature compared to bulk silver.…”