Mechanical properties of nano-silver joints as die attach materials

This review traces the development of silver (Ag) as a die attach bonding material in the microelectronic packaging industry from its’ early days as micron-scale silver flakes to the recent nanoscale Ag paste and other derivatives. Basic materials properties include the composition of Ag pastes, the methods of producing Ag nanoparticles, and product applications will be presented. Key processing conditions will be discussed to elucidate different factors which influence the mechanical properties of nano-Ag joints, principally the tensile and shear strength as well as thermal fatigue properties. Success in implementing nano-scale Ag pastes could only have been possible by deriving a fundamental understanding developed in the field of processing and using ceramic and metallic nano-powders.

. This figure summarizes two main factors namely sintering time and bonding pressure influencing the shear strength of the nano-Ag joint. This work is carried out at sintering temperature of 275–285 °C. Higher sintering temperature is expected to increase the shear strength of the nano-Ag joint.Figure optionsDownload as PowerPoint slideHighlights
► This review traces the development of sintered nano-Ag joint as die attach material.
► It highlights application methods, compositions and synthesis of nano-Ag pastes.
► Key processing parameters to produce sound joints are also discussed here.
► Current development shows that nano-Ag joints can be formed reliably.
► However, knowledge gaps exist in areas such as fatigue and microstructural evolution.