Robust Cu–Cu Bonding with Multiscale Coralloid Nano-Cu₃Sn Paste for High-Power Electronics Packaging

Abstract

In this work, a multiscale coralloid nano-Cu3Sn composed of a bimodal structure (∼55 and ∼120 nm) has been successfully synthesized to meet low-cost and Pb-free packaging demands for high-power electronic application. Owing to the excellent oxidation resistance of the Cu3Sn intermetallic compounds (IMCs) and the protection of solvent poly­(ethylene glycol)-400 (PEG-400) at high temperature, the full-Cu3Sn joints sintered in air have a comparative shear strength with the joints acquired in vacuum when the sintering temperature is no more than 300 °C. The full-Cu3Sn joints acquired at 300 °C in air achieve a high bonding strength of 40.4 MPa, which is superior to those of traditional Sn-based solder joints (19 MPa) and full-Cu6Sn5 joints (17.7 MPa). The electrical resistivity of the sintered Cu3Sn films reaches 29.1 μΩ·cm in air. Cu3.02Sn0.98 is formed at the interface between the Cu substrate and sintered Cu3Sn layer, contributing to the exceptional bonding strength of the full-Cu3Sn joints. The bonding strength of the joints after high-temperature storage (HTS) tests reveals that the prepared full-Cu3Sn joints possess outstanding long-term thermal stability with a shear strength of 47.9 MPa after 800 h of storage at 250 °C. Our work breaks through the synthesis bottleneck of nano-Cu3Sn IMCs and provides the underlying insights needed to guide the design of highly stable full-IMC joints for high-temperature electronic packaging.

Nanoscale Ag-Decorated Hollow Porous CuO/SnO2 Heterojunctions for Isopropanol Detection

“…Figure S3 shows the SEM images of the coralloid Cu 3 Sn with smooth surfaces . After calcination, the surface of CuO/SnO 2 composites roughened with the original coralloid structure (Figure a).…”

“…All chemical reagents were purchased from Aladdin Shanghai Chemical Reagent Co., Ltd., and used without further purification. First, Cu 3 Sn was synthesized based on our previous work . For the CuO/SnO 2 HPs heterostructure, 1 g of Cu 3 Sn was calcined at 700 °C for 2 h in air.…”

“…Figure S3 shows the SEM images of the coralloid Cu 3 Sn with smooth surfaces. 28 After calcination, the surface of CuO/ SnO 2 composites roughened with the original coralloid structure (Figure 4a). After acid washing, some CuO was etched away from the CuO/SnO 2 , forming a porous structure in the etched places.…”

“…First, Cu 3 Sn was synthesized based on our previous work. 28 For the CuO/SnO 2 HPs heterostructure, 1 g of Cu 3 Sn was calcined at 700 °C for 2 h in air. Then, CuO/SnO 2 was added into 1.5 M HCl solution for different washing times to etch off CuO and prepare the porous CuO/SnO 2 heterostructure.…”

Synthesis of Citrate-Capped Sn Nanoparticles with Excellent Oxidation Resistance for High-Performance Electrically Conductive Adhesives

“…Metal nanoparticles are promising for manufacturing high-performance printable electronics for various applications. − Currently, metallic silver is the most widely used material, but cost-effective alternatives urgently need to be developed due to its relatively expensive cost. Tin (Sn) metal is a promising alternative to metallic silver due to its low cost, low melting point, and good chemical stability in bulk. − However, the route to obtain Sn nanoparticles and the electronic device based on them is still limited by the high intrinsic reactivity. − These nanoparticles are susceptible to re-oxidation in air, either after synthesis, during purification, or when the material is stored. − Therefore, developing tin nanoparticles with high antioxidation properties and excellent dispersibility is necessary to realize their potential fully.…”