Flip Chip bonding of bare die on a flexible PET substrate with ablated copper

The use of low-cost materials such as PET, paper, and unpackaged bare dies has become critical for cost-effective mass production, as demand for flexible hybrid electronics has skyrocketed, particular-ly for internet of things (IoT), electronic skin, and wearable applications. The advantages of this de-sign include the sustainable use of resources, such as low-cost, readily accessible, and biologically degradable raw materials, and their suitability for printed electronics applications has been well re-searched. Mostly printed silver and sputtered silver has covered this market but has its own short-comings. Combining this with techniques such as flip chip bonding and subtractive laser ablation provides us with the opportunity of fast fabrication and smaller size which can cater for new applica-tions. In this study, we look at the flip chip bonding bare die to ablated copper on a PET substrate aided with anisotropic conductive paste. Furthermore, we investigate its reliability by performing bending tests.