Robust Ag-Cu Sintering Bonding at 160 °C via Combining Ag2O Microparticle Paste and Pt-Catalyzed Formic Acid Vapor

Abstract

With the assistance of Pt-catalyzed formic acid vapor, robust Ag-Cu bonding was realized at an ultra-low temperature of 160 °C under 3 MPa for 30 min via the sintering of Ag nanoparticles in situ generated from Ag2O microparticles. The Cu oxide layer at the interface after bonding can be eliminated, which improves the bond strength and electrical conductivity of the joint. A metallic bond contact between the sintered Ag and the Cu substrate is obtained without interfacial solid solution and intermetallic phases, and the shear strength is comparable to previous bonding at a higher temperature. The bonding mechanisms were figured out by comparing the bonding with and without the Pt-catalyzed formic acid vapor. This ultra-low temperature Ag-Cu bonding method may create more flexibilities in the structure design and material selection for power device integration.

Polymer Conductive Paste Formulation by Modified Ag2O Particles

“…Recent studies have shown that silver oxide (Ag2O) particles can be reduced to Ag nanoparticles using specific solvents at low sintering temperatures. The addition of Ag2O particles to the Ag paste enhances the electrical conductivity and flexibility of the layers, as the Ag2O particles act as a bridge among Ag flakes [8], [9], [10]. Exploring the existing literature reveals the availability of a silver oxide-based paste that appears to be a low-cost, self-reducing paste for creating conductive layers printed by stencil printing and sintered by a hot plate [11].…”

A Novel Preparation of Ag Agglomerates Paste with Unique Sintering Behavior at Low Temperature

“…In our previous study, Ag 2 O paste has been used for the Ag-Cu bonding at low temperatures [23]. By reducing the copper oxide layer, Pt-catalyzed formic acid vapor can improve the adhesive properties between the sintered layer and the Cu substrates by highly reactive hydrogen radicals.…”