Fig. 1. Interconnection mechanism of low temperature sintering of nanoparticles between chip and substrate under pressure-assisted conditions^[9]. (a) Structure and sintering assembly of nanoparticle soldering paste; (b) volatilization and decomposition of organic protective shells and solvents; (c) growth of sintering neck of metal nanoparticles at low-temperature and interconnection of metal nanoparticles with substrate

Fig. 2. Growth model of sintering neck with equal radius particles, and various types of material migration in the sintering neck during sintering process^[11]. (a) Growth model of sintering neck with equal radius particles; (b) various types of material migration in the sintering neck during sintering process

Fig. 3. Nano-micron mixed-particle structure of silver nanoparticles^[26]. (a) SEM image exhibiting the agglomeration of particles; (b) schematic of configuration of “frame” and “filler”

Fig. 4. Cross sections of sintered nano-paste joint^[17]. (a) DBC with untreated surface; (b) DBC with polished surface

Fig. 5. Factors influencing strength of joint, and fractures of sintered joints in vacuum and air^[31]. (a) Effects of sintering temperature and pressure on strength of joint; (b) effects of preheating temperature and atmosphere on strength of joint; (c) fracture of sintered joints in vacuum; (d) fracture of sintered joints in air

Fig. 6. Images of different proportions of silver-copper nano paste after water drop test^[31]

Fig. 7. Experimental results of high temperature maintenance experiments in partial literatures^[39]

Fig. 8. Cross section microtopographies of silver nano solder paste joint layer at 350 ℃ in air^[23]. (a) 200 h; (b) 400 h; (c) 800 h; (d) 1200 h

Fig. 9. Influence of structure evolution of porous junction layer on strength of sintered silver joint during HTS^[23]

Fig. 10. Cross sections of sintered joints of copper nanometer solder paste and silver nanometer solder paste after thermal cycle test^[30]. (a) Sintered joint of copper nanometer solder paste; (b) sintered joint of silver nanometer solder paste

Fig. 11. Failure modes of wire-bond packaging structures after power cycling test: bond-wire lift-off, metallization layer reconstruction, and fracture of solder bonding layer^[56]

Fig. 12. Stress distribution diagrams of electronic devices obtained by finite element simulation for power cycling test and thermal cycling test^[62]

Table 1. Process parameters and joint strength of silver nanoparticle soldering paste