IMC-skeletons reinforced high-temperature interconnections through low-temperature TLP bonding and micron composite solders

The traditional nano-sintering or TLP techniques are generally expensive, time-consuming, and hence unsuitable for realizing practical mass production. Herein, we have developed an improved TLP process to rapidly produce IMC-skeleton structures across the bonding region by initiating a localized liquid-solid interaction among micron particles at traditional soldering temperatures. The developed IMC skeletons can reinforce solder alloys and provide remarkable mechanical stability and electrical capabilities at high temperatures. As a result, the IMC-skeleton strengthened interconnections exhibited higher thermal/electrical conductivity, lower hardness and almost doubled strength than traditional full-IMC joints, attaining 87.4 MPa and 30.2 MPa at room condition and 350 ℃. Meanwhile, the necessary heating time to form metallurgical bonds was shortened, one-fifth of nano-sintering and one-tenth of TLP bonding, and the material cost was significantly reduced. This proposed technique enabled the fast, low-cost manufacturing of electronics that can serve at temperatures as high as 200−350 ℃. Besides, the interfacial reactions among particles and the correlated phase evolution process were studied in this research. The formation mechanism of IMC skeletons was analyzed. The correlated influencing factors and their effect on the mechanical, thermal and electrical properties of joints were revealed, which may help the design and extensive uses of such techniques in various high-temperature/power applications.