Browsing by Author "Lai, Po-Ying"

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Effect of Pd distribution on Pd-plated Cu wire using different electronic flame off settings
(2017-03-01)
Cheng, Pi-Ying
;
Lai, Po-Ying
;
Ye, Zheng-Jie
;
Hsieh, Cheng-Li
;
Ye, Jiun-Ming
Pd-coated Cu wires show interesting properties such as good electrical conductivity, thermal conductivity, and reliability and are widely used in microelectronic packaging. However, during the formation of free air balls (FABs) and bonded balls via Pd-coated Cu wires, the electronic flame off (EFO) current setting affects Pd distribution in FABs and bonded balls. This study investigated the effect of different EFO current settings on Pd distribution during the formation of FABs and bonded balls, and also analyzed the influence of EFO current settings on FAB formation. Pd distribution in FABs and bonded balls, as well as the distribution of other elements, were observed. The corrosion on the surface of a bonded ball was observed through high temperature storage tests (HTSTs). The result revealed that there were different Pd distributions in the formation processed via different EFO current settings of FABs and bonded balls. Further, different EFO current settings also resulted in a different FAB shape. The result of HTST indicated that proportional Pd distribution could decelerate the corrosion of a bonded ball.
High temperature storage reliability of palladium coated copper wire in different EFO current settings
(2018-01-01)
Cheng, Pi-Ying
;
Lai, Po-Ying
;
Ye, Jiun-Ming
;
Chen, Tsung-Chia
;
Hsieh, Cheng-Li
In recent years, palladium-coated copper (PdCu) wire has been widely used in microelectronic packaging. The electronic flame off (EFO) current setting will affect the distribution of palladium (Pd) during the free air ball (FAB) formation of PdCu wire. This study investigates the influence of EFO current settings on Pd distribution in the FAB and the bonded ball. The distribution and concentration of Pd is observed by using an electron probe micro analyzer (EPMA). Mechanical tests are used to evaluate the bond strength of the first bond. A high temperature storage test (HTST) is performed on the packaged IC at 200 degrees C for 500 h and 1000 h. The results indicate that different EFO current settings cause either complete or partial Pd coverage on FABs, which directly affects the Pd distribution at the bonded ball interface. The wire pull and ball shear tests show the bond strength decrease under three EFO current settings after HTST. This confirms that although Pd can serve as a protective layer for the bonded ball against attack from halides from within the epoxy molding compound (EMC), incomplete Pd coating and formation of the alloy may actually aggravate the corrosion on bonded ball.