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http://dx.doi.org/10.6117/kmeps.2019.26.2.0031

Development of Polymer Elastic Bump Formation Process and Bump Deformation Behavior Analysis for Flexible Semiconductor Package Assembly  

Lee, Jae Hak (Dept. of Ultra-Precision Machines and Systems, Advanced Manufacturing Systems Research Division Korea Institute of Machinery and Materials (KIMM))
Song, Jun-Yeob (Dept. of Ultra-Precision Machines and Systems, Advanced Manufacturing Systems Research Division Korea Institute of Machinery and Materials (KIMM))
Kim, Seung Man (Dept. of Ultra-Precision Machines and Systems, Advanced Manufacturing Systems Research Division Korea Institute of Machinery and Materials (KIMM))
Kim, Yong Jin (Dept. of Ultra-Precision Machines and Systems, Advanced Manufacturing Systems Research Division Korea Institute of Machinery and Materials (KIMM))
Park, Ah-Young (Dept. of Ultra-Precision Machines and Systems, Advanced Manufacturing Systems Research Division Korea Institute of Machinery and Materials (KIMM))
Publication Information
Journal of the Microelectronics and Packaging Society / v.26, no.2, 2019 , pp. 31-43 More about this Journal
Abstract
In this study, polymer elastic bumps were fabricated for the flexible electronic package flip chip bonding and the viscoelastic and viscoplastic behavior of the polymer elastic bumps according to the temperature and load were analyzed using FEM and experiments. The polymer elastic bump is easy to deform by the bonding load, and it is confirmed that the bump height flatness problem is easily compensated and the stress concentration on thin chip is reduced remarkably. We also develop a spiral cap type and spoke cap type polymer elastic bump of $200{\mu}m$ diameter to complement Au metal cap crack phenomenon caused by excessive deformation of polymer elastic bump. The proposed polymer elastic bumps could reduce stress of metal wiring during bump deformation compared to metal cap bump, which is completely covered with metal wiring because the metal wiring on these bumps is partially patterned and easily deformable pattern. The spoke cap bump shows the lowest stress concentration in the metal wiring while maintaining the low contact resistance because the contact area between bump and pad was wider than that of the spiral cap bump.
Keywords
flexible semiconductor package; polymer elastic bump; ultra thin chip; interconnection;
Citations & Related Records
Times Cited By KSCI : 2  (Citation Analysis)
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