Technology suitable small quantity production

Term “bonding” include two different processes: diffusion bonding and electrostatic bonding. Diffusion bonding can be performed in solid and liquid state and is based on the diffusion of materials in each other that are assisted by uniform application of heat and pressure on the parts to be joined. The most widespread use of diffusion bonding in micro technology has been for die bonding of silicon chips on the gold plated substrates, using the gold-silicon eutectic. It can be used also for plane joining of ceramics to metals, e.g. copper to Al2O3 ceramic.

Electrostatic bonding (also called as anodic bonding) uses voltage instead of pressure and is applicated for glass/metal and glass/silicon joining. The component to be joined must be polished to a smooth flat finish and than heated to a temperature below the softening point of the materials. The applied voltage cause the ion drain from one material in the other, the bonding time ranges from few minutes to several hours. In order to avoid strain at the joints the materials to be joined should have a reasonable match of thermal expansion.