TUTCRIS Research Portal

TY - JOUR

T1 - Corrosion testing of anisotropic conductive adhesive interconnections on FR4, liquid crystal polymer and polyimide substrates

AU - Parviainen, Anniina

AU - Kokko, Kati

AU - Frisk, Laura

PY - 2016/1/12

Y1 - 2016/1/12

N2 - Anisotropic conductive adhesive films (ACF) have been widely studied for numerous applications. However, their resistance to corrosion in highly corrosive environments has been studied only very little. This study investigated the reliability and behaviour of ACFs in corrosive salt spray environment. ACF was used to attach flip chip (FC) components on FR4, liquid crystal polymer (LCP) and polyimide (PI) substrates and the FC packages were subjected to a salt spray test lasting 3000 h. The FC packages had daisy chain structures which were measured continuously in real time during testing. After testing cross sections of the tested packages were examined using an optical microscope and a scanning electron microscope (SEM). Most components failed during the test and the results showed significant differences between the various substrate materials. The LCP substrate performed considerably better than the other substrates and the PI substrate proved to have the poorest reliability. Corrosion of the pads on the substrates as well as open joints was seen in all substrate materials. The corrosion behaviour as well as the differences between the substrates showed that the substrate structure and material are critical factors in corrosive environments and should be carefully considered. The reliability of the ACF FC package with the LCP substrate was found to be good, as the test was very severe and no failures occurred during the first 625 h of testing and only 20% failed during the first 1000 h.

AB - Anisotropic conductive adhesive films (ACF) have been widely studied for numerous applications. However, their resistance to corrosion in highly corrosive environments has been studied only very little. This study investigated the reliability and behaviour of ACFs in corrosive salt spray environment. ACF was used to attach flip chip (FC) components on FR4, liquid crystal polymer (LCP) and polyimide (PI) substrates and the FC packages were subjected to a salt spray test lasting 3000 h. The FC packages had daisy chain structures which were measured continuously in real time during testing. After testing cross sections of the tested packages were examined using an optical microscope and a scanning electron microscope (SEM). Most components failed during the test and the results showed significant differences between the various substrate materials. The LCP substrate performed considerably better than the other substrates and the PI substrate proved to have the poorest reliability. Corrosion of the pads on the substrates as well as open joints was seen in all substrate materials. The corrosion behaviour as well as the differences between the substrates showed that the substrate structure and material are critical factors in corrosive environments and should be carefully considered. The reliability of the ACF FC package with the LCP substrate was found to be good, as the test was very severe and no failures occurred during the first 625 h of testing and only 20% failed during the first 1000 h.

KW - Anisotropic conductive adhesive

KW - Flip chip

KW - Salt spray test

KW - Corrosion

KW - Polyimide

KW - Liquid crystal polymer

KW - FR4

UR - http://www.sciencedirect.com/science/article/pii/S0026271415302237

U2 - 10.1016/j.microrel.2015.11.008

DO - 10.1016/j.microrel.2015.11.008

M3 - Article

VL - 56

SP - 114

EP - 120

JO - Microelectronics Reliability

JF - Microelectronics Reliability

SN - 0026-2714

ER -