Wire Bonders' Speak

During the eutectic die attach process, the substrate is heated to a temperature just below the solders' eutectic temperature. During the bond cycle, an incremental thermal energy is supplied to the solder layer to promote the solder melting process. Liquefied solder then penetrates both bonding surfaces. An intermetallic bond develops, which is also known as wetting.

When different metals are combined into alloys, a range of melting temperatures is created with varying proportions of each metal used, such as AuSi @ 263' AuSn at 280'. Material phases - liquid, solid, plastic -and reaster structure are usually depicted in phase diagrams . These diagrams show a distinct mass ratio at which the solid state evolves into liquid state without passing the plastic state. This ratio determines the lowest possible melting temperature for the alloy, which is of great importance to the eutectic soldering process.