Adhesion and Reliability of Anisotropic Conductive Films (ACFs) Joints on Organic Solderability Preservatives (OSPs) Metal Surface Finish

Abstract

The effect of final metal finishes of Cu electrodes on the adhesion and reliability of anisotropic conductive film (ACF) joints was investigated. Two different metal surface finishes, electroless Ni/immersion Au (ENIG) and organic solderability preservatives (OSPs) coated on Cu, were selected in this study for ACF bonding. The adhesion strength of ACF/OSP joints was higher than that of ACF/bare Cu and ACF/ENIG joints. The fracture sites of the ACF/bare Cu and ACF/ENIG joints were ACF/metal interfaces, while those of ACF/OSP joints were inside the ACF. Transmission electron microscope (TEM) and Fourier-transform infrared (FT-IR) analyses showed that the OSP coating layer on the Cu electrodes reacted with the epoxy resin of the ACFs but still remained at the bonding interface. According to the in-depth X-ray photoelectron spectroscopy (XPS) analysis, additional C-N bonds formed after the OSP-epoxy reaction and the outermost nitrogen of the OSP layer participated in curing of the epoxy resin of the ACF. Therefore, the OSP layer acted as an adhesion promoter to ACFs. Furthermore, this role of the OSP layer enhanced the reliability of the ACF/OSP joints under high temperature and humid environments, as compared to the ACF/ENIG joints.

Assembly of Surface-Mounted Devices on Flexible Substrates by Isotropic Conductive Adhesive and Solder and Lifetime Characterization

“…In the bending test, the final surface finish on the substrate has the greatest effect on the number of cycles to failure. The advantage of the investigated surfaces is the low manufacturing cost compared to coatings such as ENIG [24,25].…”

Ising Model for Conductive Percolation in Electrically Conductive Adhesives by Considering Random Arrangement of Conducting Particles

“…The properties of composites of particles dispersed in continuum media have been reported by many authors several decades, covering numerous composites, such as conductive particles dispersed in insulating adhesives (electrically conductive adhesives) for microelectronic applications (Mikrajuddin et al, 2000;Yim et al, 2008;Lin and Chen, 2008;Li et al, 2008;Lin and Chiu, 2008;Morris and Lee, 2008;Zenner et al, 2008;Inoue et al, 2008;2009;Inoue and Suganuma, 2007;2009;Kim and Paik, 2008;Mundlein et al, 2002;Li et al, 1993;Tongxiang et al, 2008;Lee et al, 2005;Sander et al, 2002;, insulating particles dispersed in Ionic adhesive for use in solid batteries or fuel cells (Mikrajuddin et al, 2000;1999), colloidal systems (Lu et al, 2006;, pharmaceutical tablets (Stromme et al, 2003) and other composites such as fibers in concrete (Newman, 2002) and fly ash-concrete (Mohan et al, 2012). One interesting phenomenon exhibited by these composites is the occurrence of percolation threshold, a quantity which divides two strongly different states, such as conductive and insulating states (Mikrajuddin et al, 2000;1999), magnetic and nonmagnetic states (Thorpe, 1978), crystal and amorphous states, Surprisingly, in recent progress, the percolation phenomena are also applied to other fields, in the past of which likely did not show any relation with material composites such as communication systems such as the internet and other Peer-To-Peer networks (PastorSatorras and Vespignani, 2007), dynamics of epidemic spreading (Anderson and May, 1992;Meyers, 2007), HIV infection to AIDS (Kamp and Bornholdt, 2002), social networks …”

Flexible organic thin film transistors with self-assembled benzimidazole-copper complex as gate insulator

“…The manufacturing processing of the SABCC gate insulator is very similar to the organic solderability preservative ͑OSP͒ film processing, a well developed technique in the field of surface finish. 16 The fabrication features of SABCC gate insulator are self-assembling, water-based processing and selectivity of deposition ͑only on Cu͒.…”

“…[17][18][19] In the OSP technique, the most prominent BIMH compound is 2-substituted BIMH that it is of considerable interest due to the excellent heat resistance for reflow soldering. 16 In our work, 2-heptyl BIMH, i. e. BIMH with ͑CH 2 ͒ 6 CH 3 at the two-position, is used to form SABCC gate insulators on Cu electrodes. The chemical structure of 2-heptyl BIMH is shown in Fig.…”