ADHESION STUDY OF NANO-PARTICLE SILVER TO ELECTRONICS PACKAGING MATERIALS
Authors: Sungchul Joo and Daniel F. Baldwin, Ph.D. Company: The George W. Woodruff School of Mechanical Engineering Georgia Institute of Technology Date Published: 10/4/2009
Abstract: To reduce electronics packaging lead time and potentially to reduce manufacturing cost, an innovative packaging process targeting rapid package prototyping (RPP) has been developed. The developed RPP process, which is based on a data-driven chip-first approach, provides electrical functionality as well as form factors for micro-systems packages. The key component of the RPP process is the nano-particle silver (NPS) interconnect. However, NPS has not yet been adequately proven for use in electronics packaging applications. Moreover, its adhesion to electronics packaging materials such as polyimide, benzocyclobutene (BCB), copper, and aluminum is found to be very weak. Thus, improving the adhesion strength of NPS will be the key issue for reliable package prototypes with NPS interconnects. In this paper, the mechanisms of NPS adhesion to organic and inorganic materials were identified as the first step to improve NPS adhesion. The adhesion of NPS to substrate materials was found to be attributed to van der Waals forces based on particle adhesion mechanisms. This finding will provide the initiative of developing an adhesion prediction model of NPS to electronics packaging materials in order to provide guidelines for improving the NPS adhesion strength to electronics packaging materials.
Key words: rapid package prototyping, nano-particle silver, adhesion, van der Waals forces