Mechanisms of Blind-hole Cu Fillings and Self-annealing Behavior of Electroplating Cu

• Main Authors: Cheng-Hsien Yang, 楊政憲
• Other Authors: Cheng-En Ho
• Format: Others
• Language: en_US
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/c9wpd8

博士 === 元智大學 === 化學工程與材料科學學系 === 107 === Blind-hole (BH) metallization via Cu electrodeposition is a critical technology for printed circuit boards (PCBs) of high-density-interconnection (HDI) because it provides excellent thermal and electrical conductivity and efficient utilization of space. The as-deposited electroplating Cu generally possesses a nanocrystalline microstructure, which is unstable and undergoes a spontaneous grain growth at room temperature within a few hours, generally termed Cu self-annealing. Although numerous publications concerning the self-annealing behavior of electroplating Cu (surface Cu), there is still limited information regarding such a time-dependent phenomenon in the BH structure. In this study, the self-annealing behavior of electroplating Cu was characterized via an ohm meter, a field-emission scanning electron microscope (FE-SEM) in combination with electron backscatter diffraction (EBSD) analysis system, and a time of flight secondary ion mass spectrometer (TOF-SIMS). A strong correlation among electrical transition, Cu crystallographic transition, and impurity distribution was established. In this study, three examined case were investigated: 1. Self-annealing behavior of electroplating Cu in the blind-hole structure (Chapter 3-1); 2. Effect of brightener concentration on recrystallization process of electroplating Cu (Chapter 3-2); 3. Direct evidence of CEAC and CDA filling mechanisms in blind holes by Cu electroplating (Chapter 3-3). This information advances our understanding of the Cu self-annealing behavior in the BH structure and the mechanisms of BH Cu fillings. This would be helpful in development of the high-density interconnection (HDI) technology in PCB.