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The shrinking solder dimensions greatly impact the reliability of devices and increase entire failure modes. Limited solder volumes can be consumed completely and transformed into intermetallic compound (IMC) microbumps. Microvoids surface when microbumps are formed and may be attributed to a mismatch of the thermal expansion coefficient between the constituents. After thermal aging at 150 °C, the stress induced by the growth of IMCs relaxes and enhances propagation of the cracks along the middle of the bumps. The brittle nature of the IMC showed minimal resistance to cracks and incurred a failure mode. [ABSTRACT FROM AUTHOR]

Presents a study which performed single and multiple energy Fe[sup+] implants in n-type InGaAs. Secondary ion mass spectrometry depth profiles in Fe[sup+] implanted InGaAs before and after annealing; Photoreflectance spectra of unimplanted and implanted InGaAs; Discussion on the resistivity of iron-doped materials.

We report electromigration induced failure on lead-free micro bumps in three-dimensional integrated circuits samples with chip on chip configuration. Compared to flip chip solder joints, micro bumps of chip-on-chip samples exhibit better electromigration resistance and are able to withstand a higher current density. No exhibited electromigration-induced failure was observed when current density was below 2 × 104 A/cm2. A threshold current density to trigger electromigration in chip-on-chip samples was found to be 3.43 × 104 A/cm2. When current density was higher than 7.5 × 104 A/cm2 at an ambient temperature of 150 °C, no void propagation through whole bump opening was found; instead, electromigration induced voids were observed at the cathode side of Al trace. [ABSTRACT FROM AUTHOR]