Pixel detector hybridization at low temperature with adhesives

Hybrid pixel detectors require reliable interconnect technologies tailored to specific pitch and die sizes. For ASIC and sensor R&D, compatibility with single-die assembly is considered essential, as chip development is typically carried out using Multi-Project Wafer (MPW) submissions. To address these requirements, innovative hybridization concepts have been developed within the CERN EP R&D program and the AIDAinnova collaboration, targeting pixel detector applications for future colliders. A single-die interconnection process based on Anisotropic Conductive Film (ACF) and Electroless Nickel Immersion Gold (ENIG) has been developed, replacing solder bumps with conductive particles embedded in adhesive films. Electrical connections are established through thermo-compression bonding. The hybridization process using ACF has been shown to achieve high interconnection yields and robust connections, particularly for applications requiring small pads and fine pitch (< 100 μm). Additionally, a low-temperature hybridization technique employing gold studs with adhesive paste is presented. This method has enabled 100% interconnection yield for large-pitch (≈1 mm) devices. These hybridization techniques offer promising solutions for the development of pixel detectors for future particle physics experiments.