Microstructure of eutectic 80Au/20Sn solder joint in laser diode package

Teo, Joseph Chee Ming; Ng, Fern Lan; Goi, L. S.; Sun, Yongzhen; Wang, Z.F.; Shi, Xu; Wei, Jun; Li, G.Y.

doi:10.1016/j.mee.2007.09.009

Cited by 27 publications

(6 citation statements)

References 30 publications

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“…A gold-tin alloy with composition close to the gold-rich eutectic point (melting at 280 o C), was used as the solder between the gold metal contacts on the laser and SOI. This provided a low thermal budget, mechanical strength and excellent Ohmic properties between the gold pads on either component [10].…”

Section: E Electrical Contactsmentioning

confidence: 99%

Tooling and procedures for hybrid integration of lasers by flip-chip technology

Mitchell

Schachler³

et al. 2020

2020 IEEE 8th Electronics System-Integration Technology Conference (ESTC)

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A method of achieving hybrid integration of laser bars on a silicon platform, using chip-flip bonding, is presented. A support structure etched into the substrate is used to provide vertical alignment to the plane utilizing a gimballed placement laser tool. In-plane accuracy is provided by bonder tolerances, with facet-to-facet alignment enabled by high magnification optics and the dimensions of the laser bar. Chip design features have increased allowed tolerances during fabrication of the support structure giving a route to higher yield in manufacture.

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Section: E Electrical Contactsmentioning

confidence: 99%

Tooling and procedures for hybrid integration of lasers by flip-chip technology

Mitchell

Schachler³

et al. 2020

2020 IEEE 8th Electronics System-Integration Technology Conference (ESTC)

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“…The gold-rich portion of the Au-Sn phase diagram is shown in Fig. 4 [18] . The IMC phases of interest in solder are β(Au 10 Sn), ζ'(Au 5 Sn) phase, ζ(Au 5 Sn)phase and δ(AuSn) phase.…”

Section: ↔ ↔ ↔ ↔mentioning

confidence: 99%

Effect of microstructure of Au80Sn20 solder on the thermal resistance TO56 packaged GaN-based laser diodes

Lin¹,

Li²,

Zhang³

et al. 2020

J. Semicond.

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Au80Sn20 alloy is a widely used solder for laser diode packaging. In this paper, the thermal resistance of GaN-based blue laser diodes packaged in TO56 cans were measured by the forward voltage method. The microstructures of Au80Sn20 solder were then investigated to understand the reason for the difference in thermal resistance. It was found that the microstructure with a higher content of Au-rich phase in the center of the solder and a lower content of (Au,Ni)Sn phase at the interface of the solder/heat sink resulted in lower thermal resistance. This is attributed to the lower thermal resistance of Au-rich phase and higher thermal resistance of (Au,Ni)Sn phase.

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“…The major requirements for HTLF solder pastes for power discrete applications (die-attach and clip-bond) include [2][3][4][5][6]: a remelting temperature higher than 260 C to maintain joint integrity while undergoing subsequent SMT reflows, a service temperature of 150 C or higher, a drop-in solution compatible with the current high-lead soldering and subsequent packaging processes, good thermal fatigue resistance, comparable or even superior electrical/thermal performance to high-lead solders, and relatively low cost. Efforts for seeking a drop-in solution with improved performance have been attempted for more than two decades.…”

Section: Introductionmentioning

confidence: 99%

A Drop-In High-Temperature Pb-Free Solder Paste That Outperforms High-Pb Pastes in Power Discrete Applications

Zhang,

Richmond,

Aserian

et al. 2023

Journal of Microelectronics and Electronic Packaging

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Sn-based high-temperature Pb-free (HTLF) solder pastes have been developed as a drop-in solution to replace high- Pb solder pastes in power discrete applications. The pastes were designed with Indium Corporation’s DurafuseVR technology, to combine the merits of two constituent powders. A SnSb-based Ag/ Cu-containing high-temperature powder, with a melting temperature above 320 degrees C, was designed to maintain high-temperature performance. A Sn-rich SnAgCu-Sb powder, with a melting temperature around 228 degrees C, was added to the paste to enhance wetting and improve joint ductility. In the design, the final joint will have the low-melting phase (the melting temperature >228 degrees C) in a controllable quantity embedded into the high-melting SnSb matrix. HTLF-1, one of the designs, maintained the bond shear strength up to 15 MPa, even around 290 degrees C. Another design, HTLF-2, has a similar bond shear strength as Pb92.5/Sn5/Ag2.5 around 290 degrees C, but exceeds substantially below 250 degrees C. The power discrete components had been built with both HTLF solder pastes for both die-attach and clip-bond through the traditional high-Pb process, which demonstrated the drop-in processing compatibility. The components survived three additional surface mounting (SMT) reflows (peak temperature upto 260 degrees C) and passed moisture sensitivity level 1 (MSL1). This confirmed that the maintained joint strength (comparable to or stronger than high-Pb), helped to keep the joint integrity within the encapsulated components in the following SMT process, even with the controlled quantity of the melting phases above 228 degrees C. Both HTLF solder pastes outperformed Pb92.5/Sn5/Ag2.5 in the resistance from drain to source when power is on (RDS(on)), even after 1,000 cycles of temperature cycling test (TCT) under 255/175 degrees C, which is attributed to the intrinsic lower electrical resistivity of Sn in both HTLF pastes. Microstructural observation had shown no corner cracks for both die-attach and clip-bond joints after TCT.

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Microstructure of eutectic 80Au/20Sn solder joint in laser diode package

Cited by 27 publications

References 30 publications

Tooling and procedures for hybrid integration of lasers by flip-chip technology

Tooling and procedures for hybrid integration of lasers by flip-chip technology

Effect of microstructure of Au80Sn20 solder on the thermal resistance TO56 packaged GaN-based laser diodes

A Drop-In High-Temperature Pb-Free Solder Paste That Outperforms High-Pb Pastes in Power Discrete Applications

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