Silver pick up during tail formation in thermosonic wire bonding process

被引：4

作者：

Lee, J. ^{[1
]}

Mayer, M. ^{[1
]}

Zhou, Y. ^{[1
]}

Hong, S. J. ^{[2
]}

Moon, J. T. ^{[2
]}

机构：

[1] Univ Waterloo, Ctr Adv Mat Joining, Microjoining Lab, Waterloo, ON N2L 3G1, Canada

[2] MK Electron Co Ltd, Yongin, Gyeonggi Do, South Korea

来源：

MICROELECTRONICS RELIABILITY | 2011年 / 51卷 / 01期

基金：

加拿大自然科学与工程研究理事会;

关键词：

BALL;

D O I：

10.1016/j.microrel.2010.06.007

中图分类号：

TM [电工技术]; TN [电子技术、通信技术];

学科分类号：

0808 ; 0809 ;

摘要：

Cu ball bonding processes are significantly less robust than Au ball bonding processes. One reason for this are higher variations observed, e.g. in the free-air ball (FAB) formation process. There is a strong influence the tail bond process has on subsequent FAB formation. Tail tips and bond fractographs made with Cu and Au wires are investigated using scanning electron microscopy. Au and Cu wires pick up Ag material (Ag pick up) from the Ag metallization of Cu leadframe diepads during wire tail breaking. Ag pick up by Cu wire is more dominant than that by Au wire. Ultrasonic friction energy is necessary in order for Ag material pick up to occur. The impact force plays an important role for Ag pick up; less pick up is observed with a higher impact force. The hardness of the free-air ball (FAB) with Ag pick up is reduced by up to 4% compared to that of a FAB made from a tail broken at the neck of a ball bond and therefore having no Ag pick up. No significant change of FAB diameter is observed in these two cases. (C) 2010 Elsevier Ltd. All rights reserved.

引用

页码：38 / 42

页数：5

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