Process optimization and reliability characterization of Ni-based Microinsert Interconnections for Flip Chip. Evaluation in Multichip Prototype

摘要

In many applications, the concept of taking two die from different technologies to create a complete system can be more cost effective than trying to integrate the two components together on the same substrate. There are economics of scale associated with this approach which enable volume production of such systems to be proposed for the future, particularly in areas where low cost and security is of paramount importance. This concept is very attractive for applications such as smart cards. These products can be thought of as a portable memory interface device which has a very sophisticated operating system that prevents the contents of the memory from being available to be changed by non qualified users. These cards are in common usage now in many applications such as Pay-TV and credit cards where any lapse in security could cause significant losses to the owner of the card or to the people supplying the service. The work to be presented in this paper describes results from test structures used to evaluate the electrical performance of a novel interconnection system for three-dimensional integration. Small spikes of Ni are formed at the point of interconnection between the two circuits by a combination of lithography and electrolytic plating. These micro-inserts can be placed at either a bond pad or at the termination of a rerouted interconnection and target dies are mounted by using a DATACON 220APM+ 'Pick & Place' tool. The dies are then finally attached by a collective thermocompression process. A multichip SIMCARD prototype based on Atmel components (NOR-Flash memory and microcontrollers) has been achieved by this way.