An interconnection apparatus and a method of forming an interconnection apparatus. Contact structures are attached to or formed on a first substrate. The first substrate is attached to a second substrate, which is larger than the first substrate. Multiple such first substrates may be attached to the second substrate in order to create an array of contact structures. Each contact structure may be elongate and resilient and may comprise a core that is over coated with a material that imparts desired structural properties to the contact structure.