This paper describes the utilization of non-destructive imaging using 3D x-ray microscopy for package development and failure analysis. Four case studies are discussed to explain our methodology and its impact on our advanced packaging development effort.

The μPILR interconnect is a copper pillar manufactured as a part of a substrate pad. In this paper, we discuss the electromigration (EM) performance of Pb-free μPILR interconnects in a multi-pair daisy chain within 150μm pitch flip-chip packages.

This paper presents preliminary results of a copper-based direct bond interconnect (DBIreg) 3D integration process that has been developed to leverage foundry standard copper dual damascene and Ziptronix bond technology to achieve scalable, very low Cost-of-Ownership, 3D interconnects with minimum foundry adoption barrier. 

Room temperature covalent bonds between bonded silicon oxide layers can be realized by forming surface and subsurface absorption layers followed by terminating outmost bonding surfaces with desired bonding groups prior to bonding.

For bonded pairs of silicon-oxide-covered wafers, the bonding energy at low temperatures is significantly enhanced by very slight etching of the silicon oxide surfaces in diluted HF aqueous solutions prior to room temperature contacting. The bonding energy is a factor of 10 higher than standard bonded pairs to about 2000 mJ/m2 after annealing at 100oC.

The bonding energy of bonded native-oxide-covered silicon wafers treated in the HNO₃ ∕ H₂O ∕ HF or the HNO₃ ∕ HF solution prior to room-temperature contact is significantly higher than bonded standard RCA1 cleaned wafer pairs after low-temperature annealing. The bonding energy reaches over 2000mJ ∕ m² after annealing at 100 °C. The very slight etching and fluorine in the chemically grown oxide are believed to be the main contributors to the enhanced bonding energy. Transmission-electron-microscopic images have shown that the chemically formed native oxide at bonding interface is embedded with many flake-like cavities. The cavities can absorb the by-products of the interfacial reactions that result in covalent bond formation at low temperatures allowing the strong bond to be retained.