29 Jan 2024 Gluing
Belongs to the material joining processes. In contrast to soldering or sintering, there is no diffusion zone between the joining material (adhesive) and the joining partners. The connection is based on adhesive forces on the surface, which are generated by polymers. These include hydrogen bonds and Van der Waals forces. Both types of bond provide weak bonding forces. Good wetting is therefore important in order to maximize surface adhesion. Roughening the surface can also help, as this increases the surface area.
In electronics, bonding is only used for non-critical components. The thermal conductivity is orders of magnitude lower compared to solder or sintered materials. Although fillers can be used, this does not change the weak bonding forces of the connection. A major advantage of adhesive bonding is that the joint can be cured not only thermally, but also with UV light, in air or with high humidity.
Hybrid sinter pastes are an interesting group of adhesives for electronics. Here, a pressureless sintering paste is mixed with an epoxy resin. This allows the advantages of bonding and sintering to be combined. These include diffusion-bound joints due to the silver as well as protection against environmental influences due to the epoxy, as the pores of the sintered compound are filled.