Active disassembly and reversible interconnection

Current joining technology especially used for electronic products, such as soldering, wire bonding, thermo-compression bonding, adhesive bonding, are not used to be designed for dismantling, even though rework or repair is indispensable in practical applications. In this paper, the concept of active disassembly and reversible interconnection is critically reviewed by considering the bonding and debonding mechanism of the materials interfaces. Disassembly process is characterized both by disassembly energy and disassembly entropy. Active disassembly is defined as such disassembly operations using an active mechanism which is built-in to the assembly macroscopically or microscopically, or even in the material itself to reduce the necessary energy and/or entropy for disassembly. The reversible interconnection is a concept for interconnection method which enables the products to be assembled and disassembled reversibly. Active assembly can be used for realizing a reversible interconnection. Several new attempts to develop a method for reversible interconnection are presented. The bonded interface is weakened by segregation of alloying elements, or by hydridation of hydrogen storage alloy used as bonding intermediate which becomes very brittle or pulverized by absorbing hydrogen. Also, selectivity of disassembly can be achieved by using temperature dependence of the phenomena of hydrogen absorption. Examples are shown to demonstrate how the concept is applied to electronic products or dismantling PWB assemblies