Influence of Hydrogen on Room-Temperature Grain Growth of Electrodeposited Cu Films

Abstract

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.

Existing States of Co-Deposited Hydrogen in Electrolessly Deposited Copper Films from EDTA Complex Bath

“…1 as a reference. 23 For the electrolessly deposited Cu film after 1 h, a pronounced desorption peak at 390 K, small desorption peaks at 500-700 K, and large desorption peaks at 900-1300 K were observed. On the other hand, for the electrodeposited Cu film, no peak was observed at around 390 K, and a pronounced desorption peak at 600 K and a shoulder peak at 710 K were observed.…”

“…For the electrodeposited Cu films with high hydrogen concentration, the grain growth and texture development proceeded concurrently with the hydrogen desorption attributed to the break-up of Vac-H clusters at room temperature. 22,23 However, such room-temperature grain growth with the hydrogen desorption was hardly observed in the electrolessly deposited Cu films. From these results, we attributed the desorption peak appearing at around 390 K (Fig.…”

“…Subsequently, we reported that the roomtemperature grain growth observed in the electrodeposited Cu films is mainly caused by the superabundant Vac-H clusters. 22,23 In this study, the existing states and amount of co-deposited hydrogen in the Cu films electrolessly deposited from an ethylenediaminetetraacetatic acid (EDTA) complex bath were analyzed using TDS.…”

“…Figure 1. Thermal desorption spectra of hydrogen from electrolessly deposited Cu films (EL-Cu) measured 1 h and 7 days after deposition.Heating rate was 5 K min −1 and holding temperature was 1300 K. The thermal desorption spectrum of hydrogen from electrodeposited Cu film (E-Cu) from an EDTA complex bath measured 1 h after deposition is shown as a reference 23. …”

Analysis of Existing States of Co-Deposited Hydrogen in Electrodeposited Pd Films

“…4) On the other hand, the lattice contraction was observed in Pd films with lower concentration of co-deposited hydrogen (x 0.4 © 10 ¹2 ) after hydrogen desorption. Such grain growth associated with the hydrogen desorption from the plating films at room temperature has also been observed in the electrodeposited Cu films with high hydrogen concentration, 5,6) and these diffusion phenomena are considered to be caused by the diffusion enhancement effect of hydrogeninduced superabundant vacancies (SAVs). 7) In this study, we have investigated the structural changes with hydrogen desorption for the electrodeposited Pd films with low hydrogen concentration in detail and analyzed the existing states of co-deposited hydrogen in Pd films.…”