Experimental Analysis of the Co-Deposition of Metal Cu and Nano-Sized SiC Particles with CTAB in Micro Via Filling

Micro via interconnection is the core of the three-dimensional (3D) packaging. The material property of the interconnection is the decisive factor of chip reliability. In this study, an innovative material modification method for micro via filling is proposed by adopting the co-deposition of metal copper (Cu) and SiC nanoparticles. Investigations focuse on defect-free filling of micro via with co-deposition method and the controllable nanoparticle amount in the nanocomposite. Cetyltrimethylammonium bromide (CTAB) is found having significant inhibition effect on Cu electrodeposition, and it is used as suppressor to avoid defects in micro via. By adjusting pH condition of the electrolyte, the absolute zeta potential of nanoparticles is increased, and agglomeration of nanoparticles is reduced. Experimental results indicate that the content of SiC nanoparticles incorporated in the nanocomposite is greatly enhanced by adding CTAB into the electrolyte, as the CTAB modified the zeta potential of these particles from negative into positive. Other factors affecting the content of SiC nanoparticle in the nanocomposite are investigated. Experimental results show that: 1) current density and duty cycle of pulse direct current (PDC) have great influence on the amount of nanoparticles in the nanocomposite; 2) ultrasound is an effective assistance facilitating the process of metal/nanoparticle co-deposition. (c) 2019 The Electrochemical Society.