The High-Adhesion Die-Cleaning Tape with Dual-Functional Groups for Die to Wafer (D2W) Hybrid Bonding

Abstract

With the rapid development of artificial intelligence, high performance computing will break through Moore's law and move toward three-dimensional (3D) package integration of chips. Hybrid bonding has become a potential solution for advanced packaging, as the interconnect pitch shrinks to less than 1 μm. Die to wafer (D2W) hybrid bonding consists of chemical mechanical polishing (CMP), blading, plasma activation, prebonding, and annealing processes. The diced dies that are attached to tape will undergo several steps such as cleaning and activation; therefore, the tape should present a high adhesion and stability property. This paper innovatively studies the adhesion and stability of tapes in a variety of chemicals and theoretically reveals the influence of the composition and structure of the tape adhesive layer on performance. Two types of tapes (A and B) from different brands have been tested and their average peeling strength on the dies was measured; the results present that tape A remains stable no matter in the acidic or alkaline solution, even with megasonics applied for a long time. The adhesive layer of tape A is closely connected to the substrate layer, and the surface roughness of 1.1 nm is much smaller than that of tape B. Besides, the XPS analysis verifies that there are abundant carboxyl and ester groups on the surface of the tape A adhesive layer, which contributes to the outstanding adhesion of dies on the tape and stability performance in a variety of chemical environments. This research reveals the reasons for the adhesion and stability performance of the tape, which will provide a theoretical basis for the selection of die cleaning tape and support the development of the D2W hybrid bonding process and high-density packaging technology.