Comparative study of ENEPIG and thin ENEPIG as surface finishes for SAC305 solder joints

Yoon, Jeong‐Won; Back, Jong-Hoon; Jung, Seung‐Boo

doi:10.1007/s10854-017-8426-9

Cited by 17 publications

(5 citation statements)

References 23 publications

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“…This section mainly discusses the morphology and evolution of IMC after reflow and aging with different surface finishes. As mentioned above, much literature [21][22][23]28] has studied the IMC composition of standard ENEPIG and OSP. In this section, the composition changes in IMC of different surface finish substrates are calculated by EDS analysis (TESCAN, Brno Czech Republic) and summarized in the cross-section of the IMC evolution process.…”

Section: The Growth Of Interface Imc During Agingmentioning

confidence: 99%

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Effect of Ni(P) Layer Thickness on Interface Reaction and Reliability of Ultrathin ENEPIG Surface Finish

Chi

Pan

et al. 2021

Materials

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Electroless Ni(P)/electroless Pd/immersion Au (ENEPIG) is a common surface finish in electronic packaging, while the Ni(P) layer increases the impedance of solder joints and leads to signal quality degradation in high-frequency circuits. Reducing the thickness of the Ni(P) layer can balance the high impedance and weldability. In this paper, the interfacial reaction process between ultrathin ENEPIG substrates with different Ni layer thicknesses (0.112 and 0.185 μm) and Sn–3.0Ag–0.5Cu (SAC305) solder during reflow and aging was studied. The bonding ability and reliability of solder joints with different surface finishes were evaluated based on solder ball shear test, drop test and temperature cycle test (TCT), and the failure mechanism was analyzed from the perspective of intermetallic compound (IMC) interface growth. The results showed that the Ni–Sn–P layer generated by ultrathin ENEPIG can inhibit the growth of brittle IMC so that the solder joints maintain high shear strength. Ultrathin ENEPIG with a Ni layer thickness of 0.185 μm had no failure cracks under thermal cycling and drop impact, which can meet actual reliability standards. Therefore, ultrathin ENEPIG has broad prospects and important significance in the field of high-frequency chip substrate design and manufacturing.

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Section: The Growth Of Interface Imc During Agingmentioning

confidence: 99%

“…A feasible method is to adjust the Ni layer thickness of ENEPIG surface finish to alleviate the above problems [22]. However, current research on the surface finish of ENEPIG is still mainly focused on the traditional ENEPIG of about 4~5 µm.…”

Section: Introductionmentioning

confidence: 99%

Effect of Ni(P) Layer Thickness on Interface Reaction and Reliability of Ultrathin ENEPIG Surface Finish

Chi

Pan

et al. 2021

Materials

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“…However, during the immersion gold plating process, ENIG corrodes the Ni (P) layer and causes cracks, which are called "black pad" phenomena [15,16]. Recently, a new solderable finish called ENEPIG finish has emerged [17,18]. A thin and dense electroless palladium layer is added between the Ni (P) layer and Au layer, which can prevent the oxidation reaction of Ni (P) and the "black pad" phenomenon thoroughly [19].…”

Section: Introductionmentioning

confidence: 99%

“…Studies on the behavior of IMC chemical reactions with ENIG and ENEPIG have been well documented. Yoon et al [18] found that needle-shaped (Cu, Ni) 6 Sn 5 IMC and P-rich Ni layer formation deteriorated the shear strengths of the ENEPIG joints. Tian et al [22] found that the shear strength of the SAC305/ENEPIG joints was consistently higher than that of the SAC305/ENIG joints due to the slightly slow growth rate of interfacial IMCs.…”

Section: Introductionmentioning

confidence: 99%

Interfacial Microstructure and Mechanical Reliability of Sn-58Bi/ENEPIG Solder Joints

et al. 2022

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The 42 wt.% Sn–58 wt.% Bi (Sn-58Bi) Ball Grid Array (BGA) solder balls were mounted to electroless nickel-electroless palladium-immersion gold (ENEPIG) pads by employing the reflow process profile. The effects of reflow cycles and aging time on the interfacial microstructure and growth behavior of intermetallic compounds, as well as the mechanical properties, were investigated. Pd-Au-Sn intermetallic compound (IMC) was formed at the Sn-58Bi/ENEPIG interface. With the increase in reflow cycles and aging time, the IMC grew gradually. After five reflow cycles, the shear strength of the Sn-58Bi/ENEPIG solder joints first decreased and then increased. After 500 h of aging duration under −40 °C, the shear strength of the Sn-58Bi/ENEPIG solder joints decreased by about 12.3%. The fracture mode transferred from ductile fracture to ductile and brittle mixed fracture owing to the fact that the fracture location transferred from the solder matrix to the IMC interface with the increase in reflow cycles and aging time.

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“…Hence, EM-induced failure has been widely researched. The failure mechanisms of solder joints induced by EM are extensively studied and many results have been obtained [ 14 , 15 , 16 , 17 ], and one of the most well-known results is that when the c -axis of β -Sn grains, which usually refers to the Sn grain orientation, is aligned or nearly aligned along the current direction, the Cu atoms diffuse quickly and the EM deterioration is more serious [ 18 , 19 ].…”

Section: Introductionmentioning

confidence: 99%

Crystallographic Characteristic Effect of Cu Substrate on Serrated Cathode Dissolution in Cu/Sn–3.0Ag–0.5Cu/Cu Solder Joints during Electromigration

Wu¹,

Ding

Qin

et al. 2021

Materials

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The crystallographic characteristic effect of Cu substrate on cathode dissolution behavior in line-type Cu/Sn–3.0Ag–0.5Cu (SAC305)/Cu solder joints during electromigration (EM) was investigated by scanning electron microscope (SEM), electron backscatter diffraction (EBSD), and first-principles calculations. The SEM and EBSD results show that the crystallographic characteristic of Cu substrate is crucial to cathode dissolution behavior under a direct current of 1.5 × 104 A/cm2 at 125 °C ± 2 °C. When the (001) plane of copper grain adjacent to the Cu3Sn/Cu interface is perpendicular or nearly perpendicular to the current direction, local cathode dissolution tips are easily formed, whereas the (111) plane remains mostly undissolved, which finally leads to the inhomogeneous cathode serrated dissolution in the substrate. The first-principles calculation results reveal that the different surface energies and energy barriers of the different crystallographic planes of Cu grains in the substrate are responsible for the local cathode dissolution tips. Adjusting the copper grain in a substrate to a crystal plane or direction that is difficult to dissolve during EM is a promising method for improving the reliability of solder joints in the future.

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Comparative study of ENEPIG and thin ENEPIG as surface finishes for SAC305 solder joints

Cited by 17 publications

References 23 publications

Effect of Ni(P) Layer Thickness on Interface Reaction and Reliability of Ultrathin ENEPIG Surface Finish

Effect of Ni(P) Layer Thickness on Interface Reaction and Reliability of Ultrathin ENEPIG Surface Finish

Interfacial Microstructure and Mechanical Reliability of Sn-58Bi/ENEPIG Solder Joints

Crystallographic Characteristic Effect of Cu Substrate on Serrated Cathode Dissolution in Cu/Sn–3.0Ag–0.5Cu/Cu Solder Joints during Electromigration

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