Interfacial mutations in the Al‐polyimide system

Abstract

Understanding the thermal stability of metal-polymer interfaces is essential for the reliability of innovative high-tech devices, including flexible electronics or satellite insulation. In this study, the interfacial stability of aluminum-polyimide (Al-PI) is investigated as a function of thermal cycling (±150°C) and thermal annealing treatments (150°C-300°C) with X-ray photoelectron spectroscopy measurements performed after peeling and cross-sectional transmission electron microscopy analysis. Small mutations in the interface chemistry and structure were detected and identified after annealing at 225°C for 140 hours, including the thickness increase of an amorphous interlayer between Al and PI of about 2 nm and a change in the failure mechanism during the peeling. Being able to trace subcritical mutations before they become fatal is essential to predict the reliability and lifetime of metal-polymer composites.

Microstructural Effects on the Interfacial Adhesion of Nanometer-Thick Cu Films on Glass Substrates: Implications for Microelectronic Devices

“… 17 , 18 However, for polymer substrate metal films also, bulk interfaces were found to change the interfacial structure significantly when the material system is exposed to elevated temperatures. 19 The glass–Cu system reveals adhesion values around 2 J/m 2 obtained by a double cantilever beam (DCB) test method. The fracture location of this materials system is the interface; a plastic zone size of around 0.31 μm accompanying the delamination has been found for Cu films with a thickness of around 100 μm.…”

“…A change in the interface chemistry due to interfacial reactions (e.g., interdiffusion of the materials) can lead to the degradation and aging of the interface properties because of the creation of bulk interfaces. A highly feared example in microelectronics is bulk copper silicides (e.g., Cu 3 Si), which form when Cu films are directly deposited on silicon. , However, for polymer substrate metal films also, bulk interfaces were found to change the interfacial structure significantly when the material system is exposed to elevated temperatures . The glass–Cu system reveals adhesion values around 2 J/m 2 obtained by a double cantilever beam (DCB) test method.…”

Materials Engineering for Flexible Metallic Thin Film Applications

“…What has been demonstrated with in-situ XRD, AFM, CLSM, and resistance measurements is brittle interlayers (D/B) and top layers (B/D) cause the ductile films to fail much sooner than if the brittle layer was not present. This behavior has implications not only for flexible electronics and sensors, but also for nanoscale multilayers [ 60 , 61 , 129 ] and thin films used in space applications [ 65 , 130 , 131 ].…”

High-Energy Electron-Irradiated Fluorinated Ethylene Polypropylene Copolymer Coatings on Al Substrates for Enhanced Metal Adhesion and Protection

“…For decades, metal–polymer composites have played an important role in a wide range of industrial fields, including microelectronics, medical equipment, automobiles, and aerospace. − Among commercial polymers, fluorocarbon polymers (FPs) have excellent nonadhesiveness and low friction, in addition to high heat and chemical resistances. − These properties make FPs an ideal coating material for metal sliding parts in various industrial products. However, their nonadhesiveness also makes it extremely difficult for them to adhere to or combine with metals, which has prevented their wider application.…”

“…The most effective approach for observing the chemical bonding state is X-ray photoelectron spectroscopy (XPS). , However, the analyzed volume is limited to several nanometers from the sample surface, and the interface is at a depth of several tens of micrometers. In some cases, analysis of the peeled surface is helpful. ,,, However, the nonuniformity of the peeled surface increases the difficulty of interpreting the experimental results. In addition, uniformly reducing the thickness of the FP coating or metal substrate to several nanometers is extremely difficult.…”