Development of in-house plating and hybridisation technologies for hybrid pixel detectors

Future collider experiments place demands on hybrid pixel detectors, particularly in terms of interconnect reliability across a range of die sizes and fine-pitch geometries. In development workflows based on Multi-Project Wafer (MPW) submissions, support for single-die assembly is crucial. To address these challenges, new hybridization methods have been introduced through collaborative efforts at CERN and within the AIDAinnova framework. One such approach utilizes Anisotropic Conductive Film (ACF) combined with Electroless Nickel Immersion Gold (ENIG) surface treatment to form interconnections without conventional solder bumps. Instead, conductive microparticles embedded in an adhesive layer are compressed under heat and pressure to establish electrical contact. This technique has demonstrated excellent yield and mechanical stability, especially for pitches below 100 µm, making it a strong candidate for advanced detector integration in high-energy physics applications.