Assembly solution for large-area, ultra-thin, MEMS-based transducer array dies on driver chips has been investigated using dummy Si dies and substrates. The dummy dies have a thickness of 50 μm, a bonding area on the order of 100 mm2 populated with more than a thousand through-silicon vias connecting corresponding metal pads and redistribution layer (RDL) on both sides. The dummy substrates have conventional thickness as well as necessary RDL and pads for bonding and monitoring electrical resistance and stray capacitance of interconnects. Flip-chip interconnection technology based on anisotropic conductive film (ACF) was selected for bonding and characterization. Handling and ACF bonding of ultra-thin dies to rigid substrates were eased by means of glass carriers attached to the inactive side of the dies. Proper bonding parameters were identified, providing sufficiently low interconnect resistance with satisfactory yield. Stray capacitance of interconnects was found in acceptable range, though lower stray capacitance should be further pursued. The results from this work have demonstrated the feasibility of using ACF for assembling large-area, ultra-thin dies on rigid substrates.