Interconnections based on Bi-coated SnAg solder balls

• Published in: IEEE transactions on advanced packaging Vol. 24; no. 4; pp. 515 - 520
• Main Authors: Korhonen, T.-M., Vuorinen, V., Kivilahti, J.K.
• Format: Journal Article
• Language: English
• Published: Piscataway, NY IEEE 01.11.2001; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Bismuth; Bonding; Chemicals; Coatings; Electronic equipment and fabrication. Passive components, printed wiring boards, connectics; Electronics; Eutectic temperature; Eutectics; Exact sciences and technology; Heating; Interfaces; Melting points; Melts; Metallization; Microelectronic fabrication (materials and surfaces technology); Microstructure; Precipitates; Precipitation; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Shape; Soldering; Solders; Temperature distribution; Waveform; Tin compound; Metallizing; Liquid phase; Interface structure; Microelectronic fabrication; Thermodynamic model; Electronic packaging; Bismuth; Bonding; Low temperature; Thermal characteristic; Scanning electron microscopy; Eutectic alloy; Solidification; Experimental result; Solder bump; Interconnection; Chemical coating; Soldered joint; Lead free soldering; Silver compound; Numerical simulation; Microstructure; Melting point

To decrease the bonding temperature required for eutectic SnAg solder, SnAg solder bumps were chemically coated with a pure Bi layer. During heating, a low melting eutectic forms between the Bi coating and the SnAg, enabling bonding at temperatures below the melting points of either pure Bi or SnAg...