In order to introduce new bonding methods in the area of electronic packaging a theoretical
analysis was conducted, which should give substantial information about the potential of reactive
multilayer systems (rms) to create sufficient local heat for joining processes between silicon chips
and ceramic substrates. For this purpose, thermal CFD (computational fluid dynamics) simulations
have been carried out to simulate the temperature profile of the bonding zone during and after
the reaction of the rms. This thermal analysis considers two different configurations. The first
configuration consists of a silicon chip that is bonded to an LTCC-substrate (Low Temperature
Co-fired Ceramics) using a bonding layer that contains an rms and a solder preform. The reaction
propagation speed of the reactive multilayer was set to a value of 1 m/s, in order to partially melt a
solder preform underneath a silicon chip. The second configuration, which consists only of the LTCC substrate and the rms, was chosen to study the differences between the thermal outputs of the two
arrangements. The analysis of the CFD simulations was particularly focused on interpretations of the
temperature and liquid fraction contours. The CFD thermal simulation analysis conducted contains
a melting/solidification model which can track the molten/solid state of the solder in addition to
modelling the influence of latent heat. To provide information for the design of a test-substrate for
experimental investigations, the real behaviour of Pt-100 temperature probes on the LTCC-substrate
was simulated, in order to monitor an actual bonding in the experiment. All simulations were carried
out using the ANSYS Fluent software
