Die to Wafer Hybrid Bonding for Chiplet and Heterogeneous Integration: Die Size Effects Evaluation-Small Die Applications

The Direct Bond Interconnect (DBI (R)) Ultra technology, a die-to-wafer (D2W) and die-to-die (D2D) hybrid bonding, is a platform technology that offers a hermetically sealed solid Cu-Cu interconnect through room temperature bonding and low temperature anneal. DBI wafer to wafer (W2W) bonding has been in high volume production since 2015. Advancement in D2W hybrid bonding technology in recent years has enabled recent adoption the technology by Sony [1]. AMD [2] and Intel [3]. The DBI Ultra D2W technology offers die-on-tape processing with bonding speeds comparable to mass reflow flip chip assembly. The bonding takes place at room temperature in an ambient environment in a class 1000 cleanroom. A low temperature batch anneal following bonding creates a solid Cu-Cu connection with no solder and no underfill. The value of the DBI Ultra technology can be realized in diverse products ranging from very small die to reticle-size large die. Applications such as RF, sensors and microcontrollers are in the small die domain, while GPUs and FPGAs require bonding of very large die. Ultimate SoC disaggregation implementations may include D2W bonding of mid-large sized memory die (e.g. SRAM in V-Cache) as well as ultra-small die for analog functionalities. In this paper, we present the results of D2W bonding development in die size ranging from 0.4x0.4mm to 3.2x3.0mm The module build process includes dicing, die preparation on tape, and direct pick & place from a tape frame. The bonding quality is characterized with C-mode scanning acoustic microscopy (CSAM) and cross-section microscopy analysis.