Chemo-rheological characteristics of a self-assembling anisotropic conductive adhesive system containing a low-melting point solder

• Published in: Microelectronic engineering Vol. 87; no. 10; pp. 1968 - 1972
• Main Authors: Baek, Ji-Won, Jang, Keon-Soo, Eom, Yong-Sung, Moon, Jong-Tae, Kim, Jong-Min, Nam, Jae-Do
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.10.2010; Elsevier
• Subjects: Adhesives; Anisotropic conductive adhesive; Anisotropy; Applied sciences; Brazing. Soldering; Chemical reactions; Chemo-rheology; Condensed matter: structure, mechanical and thermal properties; Conversion; Cross-disciplinary physics: materials science; rheology; Design. Technologies. Operation analysis. Testing; Differential scanning calorimetry; Electronics; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; Glass transitions; Integrated circuits; Joining, thermal cutting: metallurgical aspects; Low-melting point solder; Materials science; Metals. Metallurgy; Methods of nanofabrication; Optimization; Physics; Reductant; Self assembly; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Solders; Specific phase transitions; Anisotropic conductive adhesive; Chemo-rheology; Reductant; Low-melting point solder; Differential scanning calorimetry; Powders; Transition temperature; Wetting; Rheology; Chemical reactions; Self-assembled layers; Melting points; Interconnections; Integrated circuits; Glass transition; Solder; Integrated circuit bonding; Self-assembly; Wettability; Electronic packaging; Thermal analysis; Polymers; Soldered joints; Rheometer
• ISSN: 0167-9317; 1873-5568
• DOI: 10.1016/j.mee.2009.12.020

To achieve the excellent wettability of a solder in an anisotropic conductive adhesive (ACA) in micro-packaging technology, not only the removal of the oxidized layer of the solder but also the chemo-rheological phenomena of the thermally induced self assembly of low-melting temperature solder powders were investigated for ACA applications. Both the optimum kind and amount of reductant were determined in this study to remove the oxidized layer formed on the solder surface in ambient environment. The solder wetting test was performed to observe the chemical and rheological compatibility between the solder, polymer matrix, and reductant. The thermal analysis was done using differential scanning calorimetry (DSC) analysis and rheometer test. Several chemical reactions by the reductant were proposed, and the mechanisms were postulated. It is believed that the reductant reacts with the oxidized layer, amine, and epoxide group, respectively. The relation between conversion and glass transition temperature of the polymer matrix was also obtained from DSC.