Experiment study of dynamic looping process for thermosonic wire bonding
Microelectronics Reliability xxx (2012) xxx–xxx
Contents lists available at SciVerse ScienceDirect
Microelectronics Reliability journal homepage: www.elsevier.com/locate/microrel
Experiment study of dynamic looping process for thermosonic wire bonding
Fuliang Wang ⇑, Yun Chen, Lei Han
State Key Laboratory of High Performance Complex Manufacturing, Changsha 410083, China
School of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China
a r t i c l e
i n f o
Article history:
Received 4 October 2011
Received in revised form 20 December 2011
Accepted 17 January 2012
Available online xxxx
a b s t r a c t
Looping is a complex dynamic process affected by many interacted factors, and is becoming more and more important in the state-of-the-art thermosonic wire bonding. To provide an insight view of loop mechanism, the looping process of standard loop was experimentally studied with a high resolution and high speed video camera. The capillary trace and loop profile evolution process were obtained from looping video with a digital image process program. A phenomenological description was used to understand the looping forming mechanism. The effect of capillary trace on loop profile was investigated, and the kinks forming mechanism were discussed. The spring back and kink up were detaily described. Experiment results show that loop profile was affected by kinks number, position on gold wire and deformation. Kinks were formed by reverse motion of capillary. From the geometry point of view, kink is the wire segment with the local maximum curvature. From the mechanical point of view, kink is the partly plastic deformed wire segment with elastic deformed core inside. This study may be useful for loop design in industry and for loop dynamic research in academic.
Published by Elsevier Ltd.
1. Introduction
Thermosonic wire bonding continues to be the major package technology as sustained performance upgrading in
Contents lists available at SciVerse ScienceDirect
Microelectronics Reliability journal homepage: www.elsevier.com/locate/microrel
Experiment study of dynamic looping process for thermosonic wire bonding
Fuliang Wang ⇑, Yun Chen, Lei Han
State Key Laboratory of High Performance Complex Manufacturing, Changsha 410083, China
School of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China
a r t i c l e
i n f o
Article history:
Received 4 October 2011
Received in revised form 20 December 2011
Accepted 17 January 2012
Available online xxxx
a b s t r a c t
Looping is a complex dynamic process affected by many interacted factors, and is becoming more and more important in the state-of-the-art thermosonic wire bonding. To provide an insight view of loop mechanism, the looping process of standard loop was experimentally studied with a high resolution and high speed video camera. The capillary trace and loop profile evolution process were obtained from looping video with a digital image process program. A phenomenological description was used to understand the looping forming mechanism. The effect of capillary trace on loop profile was investigated, and the kinks forming mechanism were discussed. The spring back and kink up were detaily described. Experiment results show that loop profile was affected by kinks number, position on gold wire and deformation. Kinks were formed by reverse motion of capillary. From the geometry point of view, kink is the wire segment with the local maximum curvature. From the mechanical point of view, kink is the partly plastic deformed wire segment with elastic deformed core inside. This study may be useful for loop design in industry and for loop dynamic research in academic.
Published by Elsevier Ltd.
1. Introduction
Thermosonic wire bonding continues to be the major package technology as sustained performance upgrading in
References: packaging technology conference (EPTC 2002) (Cat. No. 02EX566); 2002. p. Please cite this article in press as: Wang F et al. Experiment study of dynamic looping process for thermosonic wire bonding. Microelectron Reliab (2012), doi:10.1016/j.microrel.2012.01.014