Anisotropic conductive materials (ACF) are film-type conductive adhesives allowing electrical and mechanical connection. They are used in applications like display production, printable flexible electronics, thermal interface materials. One of the consortium members, CondAlign AS, has developed a process that uses electric fields to align and distribute particles in polymer films. This allows production of ACFs with added functionality and reduced cost compared to other technologies (figure 1). Today, quality inspection of the fabricated sample is only performed offline and is time consuming. There was a need for developing both offline and online characterization tool in order to achieve automatic and continuous production of CondAlign s ACF.
The project aims at developing a novel, automatic roll-to-roll (R2R) process, with increased production efficiency, for continuous production of anisotropic conductive films (ACF) for electronics and biomedical applications.
SINTEF contributes with developing tools to characterize, understand better and help in optimizing the fabrication process:
- This includes development of a novel contact methods for measuring the local conductivity of ACF film (figure 2).
- Characterization of physical properties at the nanometre level by mean of SEM (figure 3).
- Optical imaging to study the spatial organization of the particles before and after alignment and to inspect inline the quality of the fabrication process (figure 4).
Figure 2: Electrical characterization of ACF samples by four points probe method.
Figure 3: SEM images of the cross section of an ACF film showing a conductive chain.
Figure 4: Spatial organization of particles before (left picture) and after (right picture) alignment as observed in microscopy.