Filling technique of through silicon via by co-depositing copper and SiC nano-particles

Through silicon via (TSV) filling with cupric ion is the core technology of the 3D-package industry, and the reliability of the copper filling for the micro via is the key to the interconnection. The coefficient of thermal expansion (CTE) of the copper column mismatches that of the silicon substrate. In order to decrease the CTE of the filled copper in the micro via, SiC nano-particles are used during the electrodeposition process of filling the micro via with copper. In this study, a special material modification method for through silicon via filling is proposed by co-depositing copper and SiC nano-particles. The cationic surfactant of fatty amine polyoxyethylene ethers (FAPEs) is used to modify the surface of SiC particles and the ultrasound is also adopted to improve the SiC nano-particles content in the micro via. Experimental results indicate that: 1) the pretreatments and concentration of SiC nano-particles are very important for co-deposition, 2) the duty cycle of pulse direct current (PDC) has great influence on the content of SiC nano-particles, 3) ultrasound can help SiC nano-particles suspend in electrolyte and the optimum power is 30 W.