Fine Pitch (≤ 10μm) Die to Wafer Cu-Cu TCB on Organic Polymer Build Up Films

The ever-evolving landscape of semiconductor technologies demands innovative solutions to enhance integration, performance, and miniaturization. To meet these evolving needs, this paper explores the compelling necessity for advanced substrates that blur the conventional boundaries between integrated circuits (ICs) and packaging. A potential strategy in achieving this paradigm shift involves the incorporation of inorganic dielectric layers (SiO2 and Si3N4) commonly used in CMOS BEOL on top of organic composite polymer layers (ABF GL-102) used in package substrate fabrication for fine pitch routing and assembly on silicon core substrates. This paper assesses the inherent limitations in existing technologies and underscores the transformative advantages offered by the integration of CMOS inorganic and organic polymer wiring layers. In addition, it provides a comprehensive examination of the properties, fabrication techniques, and integration methodologies of both methods for wiring layer formation.In this work, a double layer deposition of SiO2 (dielectric layer) and Si3N4 (polish stop) on top of a blanket ABF film has been achieved through a low temperature ICPCVD process at 90°C with satisfactory adhesion and a surface roughness of < 30nm. In addition, we demonstrate for the first time, ≤ 10 μm pitch solderless Cu-Cu die to substrate assembly on an organic build up film. An average shear force of 65.76N (more than 2x MIL-SPEC for a 6 mm
²
die) was achieved. This work demonstrates the potential of hybrid wiring layers to revolutionize the fine pitch routing and assembly processes in the intersection of ICs and packaging.