In-operando visualization of the dynamic microvia copper filling process for metal interconnection of integrated circuit

Metal Interconnection has been becoming the core technology in integrate circuit (IC) industry at post-Moore's law era from chip manufacturing through advanced 3D packaging to high density interconnection (HDI) of printed circuit boards (PCB), which is realized by electroplating copper (Cu) to fill the micro/nano-vias with various aspect ratio. However, the rational screening of Cu-electroplating additives remains challenges because there is no sufficient instrumental method for the real-time observation of the dynamic filling process. To this, we designed a visible electrolytic cell integrated with a microvia chip and recorded the dynamic microvia filling process in operando with a high-resolution video camera. The effects of suppressor, accelerator and leveler and the technique parameters were evaluated in a seeing-is-believing way, and were examined by the practical microvia filling experiments in PCB. This instrumental method, opens the “black box” of microvia filling process for metal interconnection, provides the most direct way for in-situ screening electroplating additives and will definitely facilitate the fundamental research and technical development of metal interconnection of IC manufacturing.