In order to realize vertical integration for next generation electronics packaging, purely intermetallic bonding is a promising contender to replace solder. The thermal properties of these industrially important intermetallics are relatively unstudied and poorly understood. Due to their high melting temperatures intermetallic bonds provide stability through several reflows enabling vertical packaging. However, in vertical packaging the interconnects must carry a significant portion of the heat away from the chip. In an effort to better understand the thermal capability of fully intermetallic bonding Frequency Domain Frequency Domain Thermoreflectance mapping was used to determine thermal conductivity of the arc-melted Cu3Sn with respect to crystallographic orientation. This will be complemented by electron backscatter diffraction mapping of the crystal orientation.