Cu/Sn SLID wafer-level bonding optimization

Luu, Thi-Thuy; Duan, Ani; Wang, Kaiying; Aasmundtveit, Knut E.; Høivik, Nils

doi:10.1109/ectc.2013.6575775

Cited by 12 publications

(12 citation statements)

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“…During soldering, the Cu 3 Sn layer appeared at the Cu/ Cu 6 Sn 5 interface and kept growing through continuous consumption of the Cu 6 Sn 5 layers and the Sn solder (Kato et al, 1999;Li et al, 2011). According to the Cu-Sn binary phase diagram (Luu et al, 2013), we knew that no interfacial reaction would happen at 260°C after the total transformation of Sn into Cu 3 Sn. Therefore, for Cu/Sn structures with Sn thickness less than 3 mm, it was also anticipated that Sn could be consumed completely to form Cu 3 Sn at 260°C, 1 N and 300 min.…”

Section: Methodsmentioning

confidence: 99%

“…Comparatively, under the interconnected height less than dozens of micrometers, the IMCs account for a larger proportion in the interfacial region after soldering. Even, when the soldering time is extended, the solder can be consumed completely to form IMCs, leading to the formation of full IMCs joints (Chiu et al, 2014;Flötgen et al, 2014;Kato et al, 1999;Li and Chan, 2017;Li and Agyakwa, 2010;Li et al, 2011;Luu et al, 2013;Mo et al, 2015;Shao et al, 2016Shao et al, , 2017aShao et al, , 2017bTian et al, 2014a;Yao et al, 2017aYao et al, , 2017b. In other words, when the interconnected height is less than dozens of micrometers, the interfacial structure of joints can be transformed from substrates/IMCs/solder/IMCs/substrates to substrates/IMCs/substrates with the increase of soldering time.…”

Section: Introductionmentioning

confidence: 99%

“…Undoubtedly, it is very essential to conduct studies regarding the formation of full IMCs solder joints. Currently, relevant studies mainly focus on growth kinetics of IMCs layers during the formation of full IMCs joints (Li and Chan, 2017;Li and Agyakwa, 2010;Mo et al, 2015), soldering process and interfacial phase evolution for the formation of full IMCs joints (Chiu et al, 2014;Flötgen et al, 2014;Kato et al, 1999;Li et al, 2011;Luu et al, 2013;Shao et al, 2016;Yao et al, 2017aYao et al, , 2017b and reliabilities of full IMCs joints Shao et al, 2017aShao et al, , 2017bTian et al, 2014a). For the studies regarding interfacial phase evolution, these can be divided into two parts.…”

Section: Introductionmentioning

confidence: 99%

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Morphology transformation on Cu₃Sn grains during the formation of full Cu₃Sn solder joints in electronic packaging

Yao

Jin

et al. 2018

SSMT

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Purpose This paper aims to analyze the morphology transformation on the Cu3Sn grains during the formation of full Cu3Sn solder joints in electronic packaging. Design/methodology/approach Because of the infeasibility of analyzing the morphology transformation intuitively, a novel equivalent method is used. The morphology transformation on the Cu3Sn grains, during the formation of full Cu3Sn solder joints, is regarded as equivalent to the morphology transformation on the Cu3Sn grains derived from the Cu/Sn structures with different Sn thickness. Findings During soldering, the Cu3Sn grains first grew in the fine equiaxial shape in a ripening process until the critical size. Under the critical size, the Cu3Sn grains were changed from the equiaxial shape to the columnar shape. Moreover, the columnar Cu3Sn grains could be divided into different clusters with different growth directions. With the proceeding of soldering, the columnar Cu3Sn grains continued to grow in a feather of the width growing at a greater extent than the length. With the growth of the columnar Cu3Sn grains, adjacent Cu3Sn grains, within each cluster, merged with each other. Next, the merged columnar Cu3Sn grains, within each cluster, continued to merge with each other. Finally, the columnar Cu3Sn grains, within each cluster, merged into one coarse columnar Cu3Sn grain with the formation of full Cu3Sn solder joints. The detailed mechanism, for the very interesting morphology transformation, has been proposed. Originality/value Few researchers focused on the morphology transformation of interfacial phases during the formation of full intermetallic compounds joints. To bridge the research gap, the morphology transformation on the Cu3Sn grains during the formation of full Cu3Sn solder joints has been studied for the first time.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Morphology transformation on Cu₃Sn grains during the formation of full Cu₃Sn solder joints in electronic packaging

Yao

Jin

et al. 2018

SSMT

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“…The typical description of the metallurgical reaction during this soldering process is Solid-Liquid Interdiffusion (SLID) bonding [7][8] or Transient Liquid Phase (TLP) soldering [9][10]. As reported by references [11][12], the effect of process parameters (such as time, temperature, and pressure) on the microstructure of IMC joints can be significant which requires a further understanding as far as the reliability is concerned. And also, the minimum thickness of initial solder layer needed to form a pore-free joint has also been discussed in Bosco's paper [13], where at least 10µm of initial Sn layer was suggested.…”

Section: Introductionmentioning

confidence: 99%

Microstructural and mechanical analysis on Cu–Sn intermetallic micro-joints under isothermal condition

Chen

et al. 2015

Intermetallics

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Citation: MO, L. et al., 2015 Meanwhile, some equiaxial ultra-fine grains accompanied with the Kirkendall voids, were found only in adjacent to the electroplated copper. In addition, a specific type of micropillar with the size ~5μm×5μm×12μm fabricated by focus ion beam (FIB) was used to carry out the mechanical testing by Nano-indentation, which confirmed that this type of joint is mechanically robust, regardless of its porous Cu 3 Sn IMC interconnection.

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“…To obtain a uniform growth of the IMC layers, a short holding time slightly below the melting temperature is typically used [12]. This ensures a thin IMC layer formed at the material interfaces while all materials are solid.…”

Section: Bonding Profilesmentioning

confidence: 99%

Intermetallic Bonding for High-Temperature Microelectronics and Microsystems: Solid-Liquid Interdiffusion Bonding

Aasmundtveit¹,

Luu²,

Nguyen³

et al. 2018

Intermetallic Compounds - Formation and Applications

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Solid-liquid interdiffusion (SLID) bonding for microelectronics and microsystems is a bonding technique relying on intermetallics. The high-melting temperature of intermetallics allows for system operation at far higher temperatures than what solder-bonded systems can do, while still using similar process temperatures as in common solder processes. Additional benefits of SLID bonding are possibilities of fine-pitch bonding, as well as thin-layer metallurgical bonding. Our group has worked on a number of SLID metal systems. We have optimized wafer-level Cu-Sn SLID bonding to become an industrially feasible process, and we have verified the reliability of Au-Sn SLID bonding in a thermally mismatched system, as well as determined the actual phases present in an Au-Sn SLID bond. We have demonstrated SLID bonding for very high temperatures (Ni-Sn, having intermetallics with melting points up to 1280°C), as well as SLID with low process temperatures (Au-In, processed at 180°C, and Au-In-Bi, processed at 90-115°C). We have verified experimentally the high-temperature stability for our systems, with quantified strength at temperatures up to 300°C for three of the systems: Cu-Sn, Au-Sn and Au-In.Keywords: microelectronics/microsystem assembly, bonding technology, harsh environments, wafer processing, reliability, transient liquid phase © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Motivation for SLID The challenge of die attach and interconnectionFor all electronic systems, the attachment of components to substrates and their electrical connection is a crucial part of the system. Traditionally, the processes for attachment and interconnection have been considered more a craft than a science. The historical focus of electronics and microtechnology has been on the design, manufacturing and testing of components, circuits and devices, rather than on the system integration and the processes needed for actually building the system. The 'electronic revolution' has given ever-increasing performance of devices at ever-decreasing prices for more than half a century. Initial milestones were the invention of the transistor (1947) and the integrated circuit (IC) (1958). The driving factor has been a continuous decrease in size (of components and on features of components) and cost, made possible through batch processing of silicon wafers. Single-crystal silicon is a very well-defined material with extremely well-characterized properties, allowing process technology that yields extremely small features (10 nm by 2017, with a further decrease expected). Miniaturization of components and the use of large Si wafers give a huge number of components manufactured in every batch, lowering the cost. Furthermore, miniaturization allows an increase in operating frequency (or a decrease...

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Cu/Sn SLID wafer-level bonding optimization

Cited by 12 publications

References 12 publications

Morphology transformation on Cu₃Sn grains during the formation of full Cu₃Sn solder joints in electronic packaging

Morphology transformation on Cu₃Sn grains during the formation of full Cu₃Sn solder joints in electronic packaging

Microstructural and mechanical analysis on Cu–Sn intermetallic micro-joints under isothermal condition

Intermetallic Bonding for High-Temperature Microelectronics and Microsystems: Solid-Liquid Interdiffusion Bonding

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Cu/Sn SLID wafer-level bonding optimization

Cited by 12 publications

References 12 publications

Morphology transformation on Cu3Sn grains during the formation of full Cu3Sn solder joints in electronic packaging

Morphology transformation on Cu3Sn grains during the formation of full Cu3Sn solder joints in electronic packaging

Microstructural and mechanical analysis on Cu–Sn intermetallic micro-joints under isothermal condition

Intermetallic Bonding for High-Temperature Microelectronics and Microsystems: Solid-Liquid Interdiffusion Bonding

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Morphology transformation on Cu₃Sn grains during the formation of full Cu₃Sn solder joints in electronic packaging

Morphology transformation on Cu₃Sn grains during the formation of full Cu₃Sn solder joints in electronic packaging