摘要
Ag-Cu bimetallic nanoalloy,integrating the advantages of reducing migration and cost of nano-Ag and alleviating oxidation of nano-Cu,is a prospective bonding material for power electronic packaging.The Ag-coated Cu nanoparticles(Cu@Ag NPs)paste can execute bonding with high quality at 250℃,and the achieved supersaturated Ag-Cu nanoalloy joint with ultrahigh shear strength(152 MPa)dramatically exceeds most nano-paste joints.The interstitial solid solutions with atomic-level metallurgical bonds at the interface dominantly promoted the shear strength.Besides,the numerous ultrafine nanograin,high proportion of low angle grain boundaries(7.44%)without deformation,and the Cu nanoprecipitates in the joint would improve subordinately.Furthermore,the high content(16.8%)of∑3 twin boundaries would contribute to the electrical and thermal conductivity.Thus,the multiple strengthening mechanisms with the solid solution,the second precipitated phase,and ultrafine nanograin can dramatically enhance shear strength and electro-thermal conductivity of joints for high-temperature device packaging.
基金
This work was financially supported by the National Natu-ral Science Foundation of China(No.NSFC 51775140)
A part of the work was also supported by the National Science and Technology Major Project(No.2017-VI-0009-0080)
the Guangdong Province key research and development program(No.2019B010935001)
the Shenzhen Science and Technology Plan(No.JCYJ20180507183511908)
Bureau of Industry and Information Technology of Shenzhen through the Innovation Chain and Industry Chain(No.201806071354163490).
