標題: Effect of polyimide baking on bump resistance in flip-chip solder joints
作者: Cheng, Hsi-Kuei
Feng, Shien-Ping
Lai, Yi-Jen
Liu, Kuo-Chio
Wang, Ying-Lang
Liu, Tzeng-Feng
Chen, Chih-Ming
材料科學與工程學系
照明與能源光電研究所
Department of Materials Science and Engineering
Institute of Lighting and Energy Photonics
公開日期: 1-Mar-2014
摘要: The effect of polyimide (PI) thermal process on the bump resistance of flip-chip solder joint is investigated for 28 nm technology device with aggressive extreme low-k (ELK) dielectric film scheme and lead-free solder. Kelvin structure is designed in the bump array to measure the resistance of single solder bump. An additional low-temperature pre-baking before standard PI curing increases the bump resistance from 9.3 m Omega to 225 m Omega. The bump resistance increment is well explained by a PI outgassing model established based on the results of Gas Chromatography-Mass Spectrophotometer (GC-MS) analysis. The PI outgassing substances re-deposit on the Al bump pad, increasing the resistance of interface between under-bump metallurgy (UBM) and underneath Al pad. The resistance of interface is twenty-times higher than pure solder bump, which dominates the measured value of bump resistance. Low-temperature plasma etching prior to UBM deposition is proposed to retard the PI outgassing, and it effectively reduces the bump resistance from 225 m Omega to 10.8 m Omega. (C) 2013 Published by Elsevier Ltd.
URI: http://dx.doi.org/10.1016/j.microrel.2013.11.006
http://hdl.handle.net/11536/24302
ISSN: 0026-2714
DOI: 10.1016/j.microrel.2013.11.006
期刊: MICROELECTRONICS RELIABILITY
Volume: 54
Issue: 3
起始頁: 629
結束頁: 632
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