Effects of dopant, temperature, and strain rate on the mechanical properties of micrometer gold-bonding wire

Liu, D. S.; Chao, Yang

doi:10.1007/s11664-003-0187-y

Cited by 35 publications

(10 citation statements)

References 6 publications

(1 reference statement)

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“…Generally, alloying elements are added to Au bonding wires to increase wire stiffness [1][2][3] and to increase wire sweep resistance during the epoxy molding compound (EMC) molding process. More alloying elements are added for finer wires.…”

Section: Introductionmentioning

confidence: 99%

Effects of Cu and Pd addition on Au bonding wire/Al pad interfacial reactions and bond reliability

Gam

Kim

Cho³

et al. 2006

Journal of Elec Materi

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Finer pitch wire bonding technology has been needed since chips have more and finer pitch I/Os. However, finer Au wires are more prone to Au-Al bond reliability and wire sweeping problems when molded with epoxy molding compound. One of the solutions for solving these problems is to add special alloying elements to Au bonding wires. In this study, Cu and Pd were added to Au bonding wire as alloying elements. These alloyed Au bonding wires-Au-1 wt.% Cu wire and Au-1 wt.% Pd wire-were bonded on Al pads and then subsequently aged at 175°C and 200°C. Cu and Pd additions to Au bonding wire slowed down interfacial reactions and crack formation due to the formation of a Cu-rich layer and a Pd-rich layer at the interface. Wire pull testing (WPT) after thermal aging showed that Cu and Pd addition enhanced bond reliability, and Cu was more effective for improving bond reliability than Pd. In addition, comparison between the results of observation of interfacial reactions and WPT proved that crack formation was an important factor to evaluate bond reliability.

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Section: Introductionmentioning

confidence: 99%

Effects of Cu and Pd addition on Au bonding wire/Al pad interfacial reactions and bond reliability

Gam

Kim

Cho³

et al. 2006

Journal of Elec Materi

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“…To satisfy this requirement, gold wires for stud bumping have been developed by adding several doping or alloying elements, which can be classified as either solid solution dopants, such as Pd, Ag, Pt, and Cu, or interstitial dopants, such as Be, Ca, and rare earth elements. 1 Actually, the purposes of doping were to increase wire stiffness, tensile strength for high wire sweep resistance during epoxy molding compound molding process, [1][2][3][4][5]7 and recrystallization temperature for shorter heat-affected zone formation during the electro-flame off process. 6 However, since the electrical resistivity of doped-or alloyed-gold wires was higher than that of pure gold wire (4 N gold wire), many previous studies were performed to investigate the effects of doping elements on mechanical and electrical properties of gold wires.…”

Section: Introductionmentioning

confidence: 99%

Effects of Pd addition on Au stud bumps/Al pads interfacial reactions and bond reliability

Kim

Cho

Park

et al. 2004

Journal of Elec Materi

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The main purposes for developing low-alloyed Au bonding wires were to increase wire stiffness and to control the wire loop profile and heat-affected zone length. For these reasons, many alloying elements have been used for the various Au bonding wires. Although there have been many studies reported on wire strengthening mechanisms by adding alloying elements, few studies were performed on their effects on Au bonding wires and Al pad interfacial reactions. Palladium has been used as one of the important alloying elements of Au bonding wires. In this study, Au-1wt.%Pd wire was used to make Au stud bumps on Al pads, and effects of Pd on Au/Al interfacial reactions, at 150°C, 175°C, and 200°C for 0 to 1200 h thermal aging, were investigated. Crosssectional scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and electron probe microanalysis (EPMA) were performed to identify intermetallic compound (IMC) phases and Pd behavior at the Au/Al bonding interface. According to experimental results, the dominant IMC was Au 5 Al 2 , and a Pd-rich layer was at the Au wire and Au-Al IMC. Moreover, Au-Al interfacial reactions were significantly affected by the Pd-rich layer. Finally, bump shear tests were performed to investigate the effects of Pd-rich layers on Au wire bond reliability, and there were three different failure modes. Cracks, accompanied with IMC growth, formed above a Pd-rich layer. Furthermore, in longer aging times, fracture occurred along the crack, which propagated from the edges of a bonding interface to the center along a Pd-rich layer.

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“…However, the behavior of wire with respect to the ultrasonic effect is similar to that resulting from heat [17], and the constitutive relation of gold wire considering temperature was measured by Liu et al [18], as shown in Fig. 8.…”

Section: A Fe Model Of Bonding Interfacementioning

confidence: 95%

Ultrasonic Effects in the Thermosonic Flip Chip Bonding Process

Wang

Han

2013

IEEE Trans. Compon., Packag. Manufact. Technol.

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Thermosonic flip chip (TSFC) bonding is a developing area in array microelectronic interconnection technology, and ultrasonic vibration plays an important role in TSFC bonding. To understand the ultrasonic effects at the bonding interface, a lab bonder is constructed, TSFC bonding is realized, and some ultrasonic effects (plastic deformation of the bumps on the bond pads, atom diffusion, and increased dislocation density) are observed. A dynamic finite element model of TSFC bonding is developed to analyze the stress and strain distribution at the bonding interface. The results of our study show that ultrasonic vibration causes a large cycled stress of about 288 MPa at the bonding interface, which: 1) increases dislocation density, forms dislocation nets, and provides fast diffusion channels, and 2) increases the stress gradient, provides the driver force for atom diffusion, and increases the atom diffusion flux. The large cycled stress plays a key role in forming a 25-nm diffusion layer and a good bonding strength in 100 ms at the TSFC bonding interface.Index Terms-Bonding interface, finite element (FE) model simulation, thermosonic flip chip bonding (TSFC), ultrasonic effect, ultrasonic vibration.

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Effects of dopant, temperature, and strain rate on the mechanical properties of micrometer gold-bonding wire

Cited by 35 publications

References 6 publications

Effects of Cu and Pd addition on Au bonding wire/Al pad interfacial reactions and bond reliability

Effects of Cu and Pd addition on Au bonding wire/Al pad interfacial reactions and bond reliability

Effects of Pd addition on Au stud bumps/Al pads interfacial reactions and bond reliability

Ultrasonic Effects in the Thermosonic Flip Chip Bonding Process

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