Abstract
The effects of Ag nanoparticle (Ag NP) addition on interfacial reaction and mechanical properties of Sn–58Bi solder joints using ultra-fast laser soldering were investigated. Laser-assisted low-temperature bonding was used to solder Sn–58Bi based pastes, with different Ag NP contents, onto organic surface preservative-finished Cu pads of printed circuit boards. The solder joints after laser bonding were examined to determine the effects of Ag NPs on interfacial reactions and intermetallic compounds (IMCs) and high-temperature storage tests performed to investigate its effects on the long-term reliabilities of solder joints. Their mechanical properties were also assessed using shear tests. Although the bonding time of the laser process was shorter than that of a conventional reflow process, Cu–Sn IMCs, such as Cu6Sn5 and Cu3Sn, were well formed at the interface of the solder joint. The addition of Ag NPs also improved the mechanical properties of the solder joints by reducing brittle fracture and suppressing IMC growth. However, excessive addition of Ag NPs degraded the mechanical properties due to coarsened Ag3Sn IMCs. Thus, this research predicts that the laser bonding process can be applied to low-temperature bonding to reduce thermal damage and improve the mechanical properties of Sn–58Bi solders, whose microstructure and related mechanical properties can be improved by adding optimal amounts of Ag NPs.
Highlights
IntroductionElectronic devices have been used in microelectronic package technologies [1,2,3] with advanced capabilities, such as multi-functions, high densities of input/output, and high capacities
We investigated the interfacial reactions and mechanical properties of solder joints between Sn–58Bi solders, with and without the addition of 0 to 2.0 wt.% Ag nanoparticle (Ag NP), and organic surface preservative (OSP)-finished Cu, formed using a laser bonding method
Content, the growth of Cu–Sn intermetallic compounds (IMCs) was suppressed, and the activation energies for the formation of Cu–Sn IMCs increased, regardless of the high-temperature storage (HTS) temperature
Summary
Electronic devices have been used in microelectronic package technologies [1,2,3] with advanced capabilities, such as multi-functions, high densities of input/output, and high capacities. To achieve high performance and miniaturization, various packages are mounted on an electronic substrate. The mechanical properties of bonding joints between packages and printed circuit boards (PCBs) may degrade due to thermal damage and coefficient thermal expansion (CTE) mismatches in the coefficients of thermal expansion during multiple bonding processes. To solve these problems, local low-temperature bonding processes are required. The use of Pb was banned by the Restriction of Hazardous
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
