Tuning surface microtopography for optimum thermocompression bonding performance: structure, process parameters, and mechanisms on microfluidic chips

The widespread application of microfluidic chips in biomedicine, life sciences, and food safety has generated industrialization demands, making it necessary to address key challenges in production costs and scalability. This work proposes the fabrication of an innovative microstructure in microfluidic chips to enhance thermocompression bonding performance. Through simulation, the stress mitigation effect of the energy-gathering rib (ER) and the resulting microchannel deformation are analyzed. This analysis subsequently feeds a redesign of the initial reference microchannel structure, acting as a guide. Experimental validation follows to confirm the enhancement of bonding performance by the ER. Results demonstrate that compared to the initial microchannel, the new design increases bonding strength by 123 % and reduces microchannel deformation by 6–8.46 %. Further analysis reveals that bonding strength increases by 160 % in the pressure range of 0.6–1.56 MPa. Additionally, this work advances the general understanding of the bonding strength formation mechanism by clearly elucidating the evolutionary behavior of interfacial morphology at the bonded interface. The generated knowledge accelerates the commercialization of microfluidic chips by directly improving the economic efficiency and sustainability of the fabrication process.