The influence of co deposited hydrogen on the room temperature grain growth of electrodeposited Cu films was investigated. The films were prepared from ethylenediamine (EDA) complex and ethylenediaminetetraacetic acid (EDTA) complex baths and examined with respect to hydrogen concentration, the initial microstructure, residual stress and impurities. Thermal desorption spectroscopy revealed that extremely high concentrations of hydrogen was contained in the Cu films deposited from both the EDAand EDTA complex baths. The room temperature grain growth of these Cu films proceeded after deposition and concurrently with the gradual desorption of hydrogen. During the grain growth, the (111) oriented texture remained almost unchanged but the tensile stress decreased. Compared with the Cu films electrodeposited from other types of baths, temporal changes in crystal orientation and residual stress varied in the different baths, however grain growth proceeded with a decrease in hydrogen as previous. These results indicate that the primary cause of room temperature grain growth of electrodeposited Cu films is hydrogen induced superabundant vacancies.

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This study was conducted to investigate changes in hydrogen amounts in metal films obtained using electroless nickel/immersion gold (Ni-P/ Au) and electroless nickel/electroless palladium/immersion gold (Ni-P/Pd/Au and Ni-P/Pd-P/Au) surface finishes used for microelectronic solder joints. Thermal desorption spectroscopy revealed that the Ni-P films contained large amounts of diffusible hydrogen that desorbs at room temperature. During electroless deposition of Pd and Pd-P on Ni-P films, the greater part of the hydrogen in the Ni-P films desorbed. Although no hydrogen evolution accompanied immersion gold deposition, the hydrogen amounts in Ni-P/Au, Ni-P/Pd/Au, and Ni-P/Pd-P/Au films were much greater than in films without a Au layer. Moreover, at room temperature, they remained almost unchanged for one month after deposition, indicating that the thin Au layer (＜0.1 μm) prevents hydrogen desorption from the metal films. The high hydrogen concentration in Ni-P/Au films improved solder wettability.

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