A Study of the Copper Wire Ball Bonding Processes

1992 ◽  
Vol 260 ◽  
Author(s):  
Fang Hongyuan ◽  
Qian Yiyu ◽  
Jiang Yihong
Keyword(s):  
Copper Wire ◽  
New Technology ◽  
Gold Wire ◽  
Ultrasonic Power ◽  
Maximal Strength ◽  
Ball Bond ◽  
Gold Ball ◽  
Ball Bonding ◽  
Microelectronic Components ◽  
Improve Reliability

ABSTRACTCopper ball bonding is a new technology which is expected to replace the traditional gold ball bonding and paid attention in woled recently, the technology is very important to reduce cost and improve reliability of microelectronic components. In this paper, the copper wire ball bonding processes have been studied by means of the MW-EFO metal wire ball forming device and the JWYH-2 thermosonic ball bonder. The bond strength of the ball bond under varied ultrasonic power and bonding time have been tested. The tested results show that the maximal strength of copper ball bond can be over 20g, it has advantage over the gold wire ball bonding. In this paper, the deformation process of the copper ball bond has been analyzed and viewed by SME.

Optimal Gold-Ball Bonding Parameters Determined from Ball Shear and Wire Pull Tests

2011 ◽  
Vol 71-78 ◽  
pp. 1761-1764
Author(s):  
M. Y. Tsai ◽  
R. G. Liu
Keyword(s):  
Integrated Circuit ◽  
Gold Wire ◽  
Loop Length ◽  
Ball Bond ◽  
Wire Loop ◽  
Ball Shear ◽  
Bonding Parameters ◽  
Gold Ball ◽  
Ball Bonding

In microelectronic packaging, wire bonding is the preferred method used to form electrical interconnections between integrated circuit chips and a substrate. However, ball lift (i.e., when a ball bond becomes completely detached from the chip) and wire breaking are critical problems that degrade the quality of a wire bond. In this study we considered three parameters of gold-ball bonding—ball bond thickness (7–22μm), gold-wire loop height (180–300μm), and gold-wire loop length (1050–2100μm)—and tried to determine the most suitable bond parameters to realize high-quality gold-ball bonding. For this, we experimented with four different values for each parameter considered. Ball shear and wire pull strength between chip and bond pad were used as parameters to evaluate the quality of the gold-ball bond. Experimental results revealed that the ball shear and wire pull initially increase with an increase in the gold-ball thickness up to 12μm and then starts decreasing gradually with further increases in the gold-ball thickness. Further, ball shear and wire pull between chip and bond pad were found to decrease with increasing gold-wire loop height and loop length. For achieving good-quality gold-ball bonding, a gold-ball thickness of about 12μm, and assuming that the cost of the gold consumed is a major concern, a gold-wire loop height of 180μm and loop length of 1050μm are suggested.

Failure Analysis on Power Trench MOSFET Devices with Copper Wire Bonds

2011 ◽  
Author(s):  
Huixian Wu ◽  
Arthur Chiang ◽  
David Le ◽  
Win Pratchayakun
Keyword(s):  
Failure Analysis ◽  
Copper Wire ◽  
New Technology ◽  
Analytical Techniques ◽  
Wire Bonding ◽  
Bonding Process ◽  
Wire Bonds ◽  
Copper Wire Bonding ◽  
Wet Chemical ◽  
Microelectronic Components

Abstract With gold prices steadily going up in recent years, copper wire has gained popularity as a means to reduce cost of manufacturing microelectronic components. Performance tradeoff aside, there is an urgent need to thoroughly study the new technology to allay any fear of reliability compromise. Evaluation and optimization of copper wire bonding process is critical. In this paper, novel failure analysis and analytical techniques are applied to the evaluation of copper wire bonding process. Several FA/analytical techniques and FA procedures will be discussed in detail, including novel laser/chemical/plasma decapsulation, FIB, wet chemical etching, reactive ion etching (RIE), cross-section, CSAM, SEM, EDS, and a combination of these techniques. Two case studies will be given to demonstrate the use of these techniques in copper wire bonded devices.

The Process Optimization of the First Ball Bonding for Copper Wire

2012 ◽  
Vol 503-504 ◽  
pp. 905-908
Author(s):  
Wei Zhang ◽  
Kang Wang ◽  
Chun Qing Wang
Keyword(s):  
Electrical Property ◽  
Process Optimization ◽  
Contact Force ◽  
Copper Wire ◽  
Gold Wire ◽  
Economic Advantage ◽  
Input Energy ◽  
Metallization Layer ◽  
Copper Wire Bonding ◽  
Ball Bonding

Copper wire bonding has obtained prevalent owning to its economic advantage and superior electrical property. However, the replacement of gold wire with copper wire introduces hardness related issues as copper is much harder than gold. This article reports investigations of the process optimization of ball bonding for 1.8mil copper wire. The results showed that the suitable ranges of the three key parameters were: contact force was 100~120gf, bond time was 15~25ms, and bond power was 100~110dac. When the input energy was too low, it was hard to get effective bonding. However, excessive input energy would cause chip crater and serious extrusion of metallization layer.

A Comparison of the Metallurgical Behavior of Gold and Copper Wires in Ball Bonding

1991 ◽  
Vol 226 ◽  
Author(s):  
Tomohiro Uno ◽  
K. Tatsumi ◽  
K. Mizuno ◽  
O. Kitamura ◽  
Y. Ohno
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperature ◽  
Heat Affected Zone ◽  
Copper Wire ◽  
Gold Wire ◽  
Ball Bonding ◽  
Bonding Method

AbstractA comparison was made of gold and copper wires used in ball bonding in terms of their mechanical properties, bondability and the reliability of their bond interfaces in elevated temperature environments. The ball bondability of copper and gold was evaluated through clarification of the factors which govern ball deformability. Moreover a bonding method to suppress the generation of silicon cracks was proposed for ball bonding of copper wire. As to the reliability of the heat affected zone and the bond interfaces, copper wire was found to be superior to gold wire.

Shear Ram Height Investigation for Gold Wire Bond Shear Test

2012 ◽  
Vol 622-623 ◽  
pp. 1447-1450 ◽  
Author(s):  
Z. Sauli ◽  
V. Retnasamy ◽  
A.H.M. Shapri ◽  
S. Taniselass ◽  
T.S. Ong
Keyword(s):  
Shear Test ◽  
Element Model ◽  
Gold Wire ◽  
Equivalent Strain ◽  
Von Mises Stress ◽  
Stress And Strain ◽  
Strain Response ◽  
Ball Bond ◽  
Wire Bond ◽  
Gold Ball

This paper presents the simulation of gold wire bond shear test. The stress and strain response of the gold ball bond during wire bond shear was examined. The simulation was done using a A 3D non-linear finite element model. The effects of the shear ram height on the stress and strain response of the gold ball bond were investigated. The results of the simulation confirms that shear ram height has a significant effect on the von mises stress and equivalent strain response of the gold ball bond during wire bond shear test.

Effect of Voltage Pattern on Intensity of Electromagnetic Emission during Electric Flame-Off Process of Ball Bonding Machine

2011 ◽  
Vol 418-420 ◽  
pp. 2265-2271
Author(s):  
Sarunya Puapairoj ◽  
Chiranut Sa-Ngiamsak
Keyword(s):  
Electric Field ◽  
Electromagnetic Interference ◽  
Voltage Pulse ◽  
Electromagnetic Emission ◽  
Induced Voltage ◽  
Forming Process ◽  
Ball Bond ◽  
Gold Ball ◽  
Ball Bonding ◽  
Magnetic Recording Heads

Electromagnetic interference (EMI) can degrade device performance, particularly a sensitive device such as magnetic recording heads. A high applied voltage generates a high electric field in order to break the electrical air gap during a gold ball bonding process. This work, for the first time, investigates the influence of high voltage pattern of a gold ball bond machine on both electric field and magnetic field as an electromagnetic wave by monitoring an intensity of electromagnetic interference. The investigation was carried out by simulation of a live gold ball bond machine operation by using a finite integral technique. The simulation results reveal that the voltage pattern plays an important role in the intensity of electromagnetic radiation (EMR). In conclusion, an ideal voltage pulse of 2 kV and 4 kV generates the highest EMR detected by a monopole antenna. The induced voltage occuring at the antenna reflecting the intensity of EMI blasting was as high as 33.39 V and 71.36 V, respectively. Smoothening the voltage pattern by incrasing the rise time of voltage to 100 ns only, the induced voltage at the antenna was reduced down to 99.90% and 99.92% compairing with the case of an ideal voltage pulse for the peak EFO voltage of 2 kV and 4kV respectively. This concludes the importance of the voltage pattern during a free air ball forming process; hence lowering the risk of the highly sensitive deivce to be damaged by EMI blasting.

An Evaluation of Gold and Copper Wire Bonds on Shear and Pull Testing

2005 ◽  
Vol 128 (3) ◽  
pp. 192-201 ◽  
Author(s):  
S. Murali ◽  
N. Srikanth ◽  
Charles J. Vath
Keyword(s):  
Void Nucleation ◽  
Copper Wire ◽  
Intermetallic Layer ◽  
Bonding Layer ◽  
Ball Bond ◽  
Wire Bonds ◽  
Aluminum Metallization ◽  
Gold Ball ◽  
Ball Bonds ◽  
Pull Testing

In microelectronic packaging technology wire bonding is a common interconnect technique. The quality and reliability of wire bonds are generally evaluated by ball shear and stitch pull testing. From the load versus time and load versus tool tip displacement plots of the shear test, three regions can be observed. Region I primarily exhibits elastic-plastic deformation occur, while crack nucleate in region II which propagates in region III which finally ends in a catastrophic failure. Fractographs reveal in the case of gold ball bonds shows fracture occurs in Al bond pad metallization close to Au-Al intermetallics. In Cu ball bonds of 1, 2, and 4ml wire sizes also Al bond pad metallization cracks but penetrate deeper into the pad which indirectly shows that the bonding layer is stronger than that of gold ball bonds. Optical microscopic observation of the sheared copper bond surfaces reveal sticking of Al which provides qualitative information of the area of the bond between the ball bond and the bond pad. In thermally aged gold ball bonds, the gold above the intermetallic layer fractures. The energy required to fracture a gold or copper ball bond of 1ml wire size is around 370J∕m2, while an aged gold ball bond consumes about 520J∕m2. Void nucleation and coalescence mechanism of ductile fracture takes place in the ball and stitch bonds, however, silicon particles may be the preferential void nucleation sites in bond pad aluminum metallization failures. To understand the second bond strength, a stitch pull test was conducted and the results showed the neck of the stitched wire cracks thus leaving behind a tail bond on the lead finger.

A friction based approach for modeling wire bonding

2013 ◽  
Vol 2013 (1) ◽  
pp. 000208-000212 ◽  
Author(s):  
Simon Althoff ◽  
Jan Neuhaus ◽  
Tobias Hemsel ◽  
Walter Sextro
Keyword(s):  
Contact Area ◽  
Copper Wire ◽  
Point Contact ◽  
Welding Process ◽  
Friction Model ◽  
Ultrasonic Power ◽  
Physical Effects ◽  
Wedge Bonding ◽  
Work Done ◽  
Do So

A model approach for wedge/wedge bonding copper wire is presented. The connection between wire and substrate is based on a variety of physical effects, but the dominant one is the friction based welding while applying ultrasound. Consequently, a friction model was used to investigate the welding process. This model is built up universal and can be used to describe the formation of micro welds in the time variant contact area between wire and substrate. Aim of the model is to identify the interactions between touchdown, bond normal force, ultrasonic power and bonding time. To do so, the contact area is discretized into partial areas where a Point Contact Model is applied. Based on this approach it is possible to simulate micro and macro slip inside the contact area between wire and substrate. The work done by friction force is a main criterion to define occurring micro joints which influence the subsequent welding.

High Temperature Storage Reliability of Bond Resistance of Palladium-Coated Copper Ball Bonds

2017 ◽  
Vol 2017 (1) ◽  
pp. 000432-000437 ◽  
Author(s):  
Michael David Hook ◽  
Michael Mayer ◽  
Stevan Hunter
Keyword(s):  
High Temperature ◽  
Ball Bond ◽  
Wire Bonds ◽  
High Temperature Storage ◽  
Ball Bonding ◽  
Ball Bonds ◽  
Bond Pads ◽  
Wire Resistance ◽  
Temperature Storage

Abstract Reliability of wire bonds made with palladium-coated copper (PCC) wire of 25 μm diameter is studied by measuring the wire bond resistance increase over time in high temperature storage at 225 °C. Ball bonds are made on two bond pad thicknesses and tested with and without mold compound encapsulation. Bond pads are aluminum copper (Al-0.5%Cu), 800 nm and 3000 nm thick. The wirebonding pattern is arranged to facilitate 4-wire resistance measurements of 12 bond pairs in each 28-pin ceramic test package. The ball bonding recipe is optimized to minimize splash on 3000 nm Al-0.5%Cu with shear strength at least 120 MPa. Ball bond diameter is 61 μm and height is 14 μm. Measurements include bond shear test data and in-situ resistance before and during high temperature storage. Bonds on 3000 nm pads are found to be significantly more reliable than bonds on 800 nm pads within 140 h of aging.

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