A novel multiscale silver paste for die bonding on bare copper by low-temperature pressure-free sintering in air
| Autor: | Lei Wang, Yunhui Mei, Xin Li, Guo-Quan Lu, Li Jie |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
010302 applied physics
Copper oxide Materials science Mechanical Engineering Thermal resistance Surface force Metallurgy chemistry.chemical_element Nanoparticle Sintering 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Copper chemistry.chemical_compound chemistry Mechanics of Materials Plating 0103 physical sciences Nano lcsh:TA401-492 lcsh:Materials of engineering and construction. Mechanics of materials General Materials Science Composite material 0210 nano-technology |
| Zdroj: | Materials & Design, Vol 140, Iss, Pp 64-72 (2018) |
| ISSN: | 0264-1275 |
| Popis: | Nanosilver sintering is expected to overcome the limitation of relatively high production cost and become widely available for the die bonding of power electronics. A potential application of nanosilver sintering is bare copper bonding, where replacing substrates with auxiliary silver or other plating that can damage bonding would be advantageous. Here, we introduce a novel multiscale silver paste containing both nanoparticles (20–100 nm) and microparticles (1–5 μm) for the bonding of high-power chips on a bare copper substrate by pressure-free sintering in air. The energy potential difference generated in the surface force field was critical in the formation of sintering necks between the nano and microparticles, which, together with other microparticles, formed the high-density sintered structure. Despite the development of a copper oxide film, the interfacial bonding was comparable to or higher than the sintering force due to the high surface energy of porous sintered structure and easy diffusion of nanoparticles occurred. A processing temperature of 265 °C was considered optimal for bare copper joint (shear strength: 53 MPa, transient thermal impedance: 0.132 °C/W) considering the trade-off between achieving excellent mechanical and thermal properties while minimizing oxidation. Keywords: Silver nanoparticles, Silver microparticles, Bare copper, Air sintering, Pressure-free bonding |
| Databáze: | OpenAIRE |
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