This paper discusses the use of modelling techniques to predict the reliability of an anisotropic conductive film (ACF) flip chip in a humid environment. The purpose of this modelling work is to understand the role that moisture plays in the failure of ACF flip chips.
A 3D macro‐micro finite element modelling technique was used to determine the moisture diffusion and moisture‐induced stresses inside the ACF flip chip.
The results show that the ACF layer in the flip chip can be expected to be fully saturated with moisture after 3 h at 121°C, 100%RH, 2 atm test conditions. The swelling effect of the adhesive due to this moisture absorption causes predominately tensile stress at the interface between the adhesive and the metallization, which could cause a decrease in the contact area, and therefore an increase in the contact resistance.
This paper introduces a macro‐micro modelling technique which enables more detailed 3D modelling analysis of an ACF flip chip than previously.
