High-speed Cu electrodeposition and its solderability

Lee, P.T.; Wu, Ying-Syuan; Lin, Ping-Chou; Chen, C.C.; Hsieh, W.Z.; Ho, Cheng–En

doi:10.1016/j.surfcoat.2016.11.016

Cited by 28 publications

(15 citation statements)

References 35 publications

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“…Ho's group have published a series of research papers on the effects of impurity residues [21,49,55,56]. They reported that the impurity residues (carbon, oxygen, chlorine, sulfur) combined with crystallographic defects caused the formation of pinholes on the surface of the Cu-plated film subjected to post-etching.…”

Section: Effects Of Impurity Residues On Electroplated Cu Layermentioning

confidence: 99%

“…The bottom-up Cu grain growth accompanying the grain boundary elimination forced the impurities to redistribute or out-diffuse to the film surface [55]. Ho et al [56] further studied the effect of plating current density on the high-speed electrodeposition of Cu for pillar construction. Significant amounts of impurities (especially Cl) were incorporated in a submicron-crystallized Cu-plated pillar with a high current density.…”

Section: Effects Of Impurity Residues On Electroplated Cu Layermentioning

confidence: 99%

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Impurity Effects in Electroplated-Copper Solder Joints

Lee

Chen

2018

Metals

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Copper (Cu) electroplating is a mature technology, and has been extensively applied in microelectronic industry. With the development of advanced microelectronic packaging, Cu electroplating encounters new challenges for atomic deposition on a non-planar substrate and to deliver good throwing power and uniform deposit properties in a high-aspect-ratio trench. The use of organic additives plays an important role in modulating the atomic deposition to achieve successful metallic coverage and filling, which strongly relies on the adsorptive and chemical interactions among additives on the surface of growing film. However, the adsorptive characteristic of organic additives inevitably results in an incorporation of additive-derived impurities in the electroplated Cu film. The incorporation of high-level impurities originating from the use of polyethylene glycol (PEG) and chlorine ions significantly affects the microstructural evolution of the electroplated Cu film, and the electroplated-Cu solder joints, leading to the formation of undesired voids at the joint interface. However, the addition of bis(3-sulfopropyl) disulfide (SPS) with a critical concentration suppresses the impurity incorporation and the void formation. In this article, relevant studies were reviewed, and the focus was placed on the effects of additive formula and plating parameters on the impurity incorporation in the electroplated Cu film, and the void formation in the solder joints.

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Section: Effects Of Impurity Residues On Electroplated Cu Layermentioning

confidence: 99%

Section: Effects Of Impurity Residues On Electroplated Cu Layermentioning

confidence: 99%

Impurity Effects in Electroplated-Copper Solder Joints

Lee

Chen

2018

Metals

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“…The mechanical behavior assessment of electronic assemblies and handheld devices, like cell phones and tablets, under shock and impact has become a major goal in the past few decades. Therefore, researchers all over the globe have conducted numerous experiments, numerical and analytical research studies to properly evaluate the reliability and fatigue life behavior of electronic packages when exposed to impact loadings (Xi et al , 2015; Gharaibeh et al , 2013; Kallolimath and Zhou, 2016; Ghaffarian, 2022; Gharaibeh and Pitarresi, 2022). Besides, because of the continuous demand for thinner and more reliable devices, land grid array (LGA) interconnects are becoming an appealing and much fashionable design choice over the conventional ball grid array (BGA) solder balls (Joshi et al , 2012; Kujala et al , 2002a).…”

Section: Introductionmentioning

confidence: 99%

“…A contradiction in such behavior is shown by Tee et al's (2003Tee et al's ( , 2006 finite element (FE) study, where the tin-lead solder stresses are decreased by 11% when the solder height is increased by 20%. In addition to solder dimensions, the copper pad finish and electroplating process have a significant effect on the mechanical response, that is, shear strength, of both lead-based and lead-free solder because of the formation of brittle intermetallic compound layers (IMCs) which further quicken the mechanical failure of the interconnects, especially when combined with aging processes (Lee et al, 2017;Ha et al, 2009;Yoo et al, 2009). Darveaux et al's (2015) experiments showed that the LGA reliability is approximately 1.5 times better than BGA in thermal cycling.…”

Section: Introductionmentioning

confidence: 99%

Drop and impact reliability investigation of BGA and LGA interconnects

Gharaibeh

Pitarresi

2023

SSMT

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Purpose Because of growing demand for slim, thin and cheap handheld devices, reduced-volume solder interconnects like land grid array (LGA) are becoming attractive and popular choices over the traditional ball grid array (BGA) packages. This study aims to investigate the mechanical shock and impact reliability of various solder alloys and BGA/LGA interconnect configurations. Design/methodology/approach Therefore, this paper uses drop testing experiments and numerical finite element simulations to evaluate and compare the reliability performance of both LGA and BGA components when exposed to drop and impact loadings. Additionally, three common solder alloys, including 63Sn37Pb, SAC305 and Innolot, are discussed. Findings The results of this study showed that electronic packages’ drop and impact reliability is strongly driven by the solder configuration and the alloy type. Particularly, the combination of stiff solder alloy and shorter joint, LGA’s assembled with SAC305, results in highly improved drop reliability. Moreover, the BGA packages’ performance can be considerably enhanced by using ductile and compliant solder alloys, that is, 63Sn37Pb. Finally, this paper discussed the failure mode of the various solder configurations and used simulation results to explain the crack and failure situations. Originality/value In literature, there is a lack of published work on the drop and impact reliability evaluation and comparison of LGA and BGA solders. This paper provides quantitative analysis on the reliability of lead-based and lead-free solders when assembled with LGA and BGA interconnects.

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“…A literature review revealed that the Cu microstructure (e.g., grain size, grain boundary, and crystallographic orientation) [4][5][6][7] and the impurity contents in the Cu platings [6][7][8] both can vary with j, which significantly influence the growth of intermetallic compounds (IMCs) and the formation of voids at the joint interface, [7][8][9] thus governing the packaging reliability of the Cu circuits. Lee et al 7 investigated the effects of j on the Cu pillar microstructure and the soldering reaction (liquid-solid reaction) between the Cu pillars and a 96.5 wt% Sn-3 wt% Ag-0.5 wt% Cu (termed Sn-3Ag-0.5Cu) alloy. They found that the Cu grains could significantly decrease from the microscale to a submicron scale as j was increased from 2 A/dm 2 to 10 A/dm 2 .…”

mentioning

confidence: 99%

High-Speed Cu Electrodeposition and Reliability of Cu Pillar Bumps in High-Temperature Storage

Lee

et al. 2018

J. Electrochem. Soc.

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This study was conducted to investigate the microstructure, impurity distribution, and mechanical reliability of copper pillar bumps (CPBs) by means of scanning electron microscopy in conjunction with an electron backscatter diffraction analysis system, transmission electron microscopy, time-of-flight secondary ion mass spectrometry, and high-speed ball shear (HSBS) testing. After soldering reaction and subsequent isothermal annealing at 180 • C, a typical Cu 6 Sn 5 /Cu 3 Sn dual layer formed at the solder/Cu pillar interface when the pillars were electrodeposited using a low j (2 A/cm 2 ). Interestingly, an abnormal, interwoven lamellar structure consisting of Cu 6 Sn 5 , Cu 3 Sn, and Cu 10 Sn 3 phases accompanying numerous voids and impurities (including Cl and CN) could be obtained in the high j case, particularly for j = 10 A/cm 2 . The propagation of this abnormal microstructure and voids at the interface seriously deteriorated the shear resistance of CPBs in HSBS testing. These investigations revealed that j is an important factor of the CPB microstructure and might greatly affect its mechanical reliability after high-temperature storage. Based on the crystallographic and chemical analysis, we proposed a unified argument associated with the formation mechanism of the undesired joint microstructure to explain this rather unusual phenomenon.

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High-speed Cu electrodeposition and its solderability

Cited by 28 publications

References 35 publications

Impurity Effects in Electroplated-Copper Solder Joints

Impurity Effects in Electroplated-Copper Solder Joints

Drop and impact reliability investigation of BGA and LGA interconnects

High-Speed Cu Electrodeposition and Reliability of Cu Pillar Bumps in High-Temperature Storage

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