Optoelectronic packaging assemblies are provided that are useful for optical data, transfer In high performance computing applications, board to board in data centers, memory to CPU, switch/FPGA (field programmable gate array) for chip to chip interconnects, and memory extension. The packaging assemblies provide fine pitch flip chip interconnects and chip stacking assemblies with good thermo-mechanical reliability. Underfill dams and optical overhang regions and are provided for optical interconnection.