A diffusional model for transient liquid phase bonding

Transient Liquid Phase (TLP) bonding for the Au/Sn/Au system is discussed in terms of a numerical diffusional model. Results suggest that the bonding process is sensitive to metal thicknesses, the heating rate, and the age of the sample prior to bonding. Simulations for rapidly heating a fresh sample show multiple peaks in the liquid depth vs time curve, each corresponding to a different solid phase composition. These peaks disappear sequentially as either the heating rate is decreased, or the sample age is increased. Results of this study have practical implications regarding the application of TLP bonding in manufacturing.