Effects of Phenolic Resin Addition on the Electrical Conductivity and Mechanical Strength of Nano-Copper Paste Formed Cu-Cu Joints

• Published in: Journal of electronic materials 2017-11, Vol.46 (11), p.6388-6394
• Main Authors: Gao, Runhua, Shen, Jun, Xie, Fuxing, Zuo, Yang, Wu, Dong
• Format: Article
• Language: English
• Subjects: Bonded joints; Bonding strength; Characterization and Evaluation of Materials; Chemistry and Materials Science; Conductivity; Copper; Electrical resistivity; Electronics and Microelectronics; Instrumentation; Low pressure; Materials Science; Mechanical properties; Nanoparticles; Optical and Electronic Materials; Oxidation; Pastes; Resins; Shear strength; Solid State Physics
• ISSN: 0361-5235; 1543-186X
• DOI: 10.1007/s11664-017-5669-4

Cu-Cu joints bonded by nano-copper pastes with different amounts of phenolic resin were developed at a low temperature (240°C) and a low pressure (1 MPa). The shear strengths of the joints were measured and the bonding layers were observed by scanning electron microscopy. The electrical conductivity of the joints was tested by a parameter analyzer. The results indicated that 2% phenolic resin in the pastes doubled the shear strength of Cu-Cu joints compared to joints made with 0%, 5% and 8% phenolic, because it filled the voids and coated sintered Cu nanoparticles in the joints without affecting the electrical conductivity of the Cu-Cu joint. This was because 2% phenolic paste prevented Cu nanoparticles from oxidation. However, 8% phenolic resin led to an increase of electrical resistivity due to the insulating property of phenolic resin, and a decrease of shear strength due to the hindrance to sintering between the nanoparticles.