Adhesion and Progressive Debonding of Polymer/Metal Interfaces: Effects of Temperature and Environment

Abstract

The interfacial fracture properties of a representative polymer/metal interface commonly found in microelectronic applications are examined. The double cantilever beam (DCB) configuration was used to investigate the effects of environmental variables on interfacial adhesion and progressive delamination under monotonic and cyclic fatigue loading conditions. The steady-state interfacial fracture energy, Gss, taken from the plateau of the R-curve, of a representative silica-filled Phenol-Novolac epoxy on a Nielectroplated Cu substrate showed little sensitivity to the presence of moisture. On the other hand, both the initiation interfacial fracture energy, Gi, and the entire progressive debond curve under fatigue loading were remarkably sensitive to moisture and temperature, respectively. Debonding is modeled in terms of interface structure, chemistry using chemical reaction rate theory, and relaxation process at the debond tip. The activation energy for stage I debond growth is found to be 140 kJ/mol and 63 kJ/mol for stage II for the current polymer/metal interface.

Effects of an adhesion promoter on the debond resistance of a metal-polymethylmethacrylate interface

“…Models based on reaction rate kinetics have been used to understand the effect of moisture activity and temperature on the debond growth-rate behavior. [12][13][14] To improve adhesion and enhance resistance to environmental degradation, techniques have emerged that use organosilane adhesion promoters to replace the weak secondary bonds (VDW) at the polymersubstrate interface with stronger covalent bonds. [15][16][17] Silane adhesion promoters are typically used as intermediate layers between inorganic substrates (e.g., glass or metal) and the polymer or adhesive layer.…”