The influence of additives on microstructure evolution of electrochemically deposited copper films

• Main Author: Gao, Jie
• Language: English
• Published: 2009
• Online Access: http://hdl.handle.net/2429/15192

This thesis presents an investigation of the effects of additives on kinetics of deposition and microstructure evolution of Cu films, which were electrochemically deposited (ECD) on Au substrates. The rate of bulk Cu deposition was quantified with cyclic voltammetry. The self-annealing of the as-deposited Cu films was recorded at room temperature with resistivity measurements. Furthermore, the grain size evolution during self-annealing was characterized by X-ray diffraction. The challenges associated with these measurements such as reproducibility tests, the effects of substrate quality, and the aging of chemicals is discussed in detail. A systematic error of resistivity measurements is reduced to 3% by correcting the resistivities value. Considering the sensitivity in the measurement of initial absolute resistivity, it is suggested to use the normalized resistivity for presenting the results. XRD technique is a good way for estimating the microstructure evolution during self-annealing. However, the use of resistivity techniques is recommended to investigate self-annealing kinetics. The additives, PEG and SPS play an important role in influencing the deposition rate and self-annealing rate, whereas, the effect in JGB also cannot be neglected especially its influence during underpotential deposition (UPD) stage and on the rate of self-annealing. A suitable selection of the type and the concentration in additives will be the key to control the kinetics of deposition and self-annealing in order to match the requirements of Cu interconnects.