Effect of Thickness of Pd Plating Layer on Shear Strength of Lead-Free Solder Ball Joint With Electroless Ni/Pd/Au Plated Electrode

2011 ◽  
Author(s):  
Takahiro Kano ◽  
Ikuo Shohji ◽  
Tetsuyuki Tsuchida ◽  
Toshikazu Ookubo
Keyword(s):  
Reaction Layer ◽  
Shear Force ◽  
Solder Ball ◽  
Lead Free ◽  
Joint Interface ◽  
Lead Free Solder ◽  
Solder Balls ◽  
Free Solder ◽  
Ball Joints ◽  
Electroless Ni

An electroless Ni/Pd/Au plated electrode is expected to be used as an electrode material for lead-free solder to improve joint reliability. The aim of this study is to investigate the effect of the thickness of the Pd layer on joint properties of the lead-free solder joint with the electroless Ni/Pd/Au plated electrode. Solder ball joints were fabricated with Sn-3Ag-0.5Cu (mass%) lead-free solder balls and electroless Ni/Pd/Au and Ni/Au plated electrodes. Ball shear force and microstructure of the joint were investigated. The (Cu,Ni)6Sn5 reaction layer formed in the joint interface in all specimens. The thickness of the reaction layer decreased with increasing the thickness of the Pd layer. In the joint with a Pd layer 0.36 μm thick, the remained Pd layer was observed in the joint interface. In the joint, impact shear force decreased compared with that of the joint without the remained Pd layer. On the contrary, when the thickness of the Pd layer was less than 0.36 μm, the Pd layer was not remained in the joint interface and impact shear force improved. Impact shear force of the joint with the electroless Ni/Pd/Au plated electrode was higher than that with the electroless Ni/Au one.

Effect of Electrode Material on Joint Strength of Soldered Joints With Sn-Bi and Sn-Bi-Sb Lead-Free Solder Balls

2013 ◽  
Author(s):  
Akihiro Hirata ◽  
Ikuo Shohji ◽  
Tetsuyuki Tsuchida ◽  
Toshikazu Ookubo
Keyword(s):  
Shear Force ◽  
Lead Free ◽  
Joint Interface ◽  
Intermetallic Compound Layer ◽  
Lead Free Solder ◽  
Ball Shear ◽  
Joint Properties ◽  
Solder Balls ◽  
Plating Solution ◽  
Free Solder

The aim of this study is to investigate the joint properties of Sn-58mass%Bi and Sn-57mass%Bi-0.5mass%Sb low-melting lead-free solder balls on the electroless Ni/Au and Ni/Pd/Au plated Cu electrodes fabricated with a lead-free plating solution. Compared with the conventional Ni plating solution containing lead, the soldered joints with Ni/Au and Ni/Pd/Au electrodes fabricated with the lead-free plating solution showed comparable joint properties. In the joints with Ni/Pd/Au electrodes, ball shear force increased when the Pd layer is dissolved into solder by multi reflows. In both joints with Ni/Au and Ni/Pd/Au electrodes, a part of the Ni layer was dissolved into solder and thus the (Ni,Cu)3Sn4 intermetallic compound layer formed at the joint interface. Ball shear force decreased upon aging due to the growth of the (Ni,Cu)3Sn4 layer at the joint interface.

Comparison of Impact Properties of Sn-9Zn and Sn-3Ag-0.5Cu Lead-Free Solder Ball Joints

2008 ◽  
Vol 385-387 ◽  
pp. 429-432 ◽  
Author(s):  
Ikuo Shohji ◽  
Satoshi Shimoyama ◽  
Hisao Ishikawa ◽  
Masao Kojima
Keyword(s):  
Solder Ball ◽  
Impact Force ◽  
Lead Free ◽  
Joint Interface ◽  
Impact Properties ◽  
Joint Fracture ◽  
Free Solder ◽  
Ball Joints ◽  
Electroless Ni ◽  
The Impact

Impact properties of solder ball joints with Sn-9mass%Zn and Sn-3mass%Ag- 0.5mass%Cu lead-free solders were investigated under aging at 423 K. In the case of the joints with Cu electrodes, both Sn-9Zn and Sn-3Ag-0.5Cu joints have similar impact forces before aging. For the Sn-3Ag-0.5Cu joint, fracture occurred in an intermetallic compound (IMC) layer formed in a joint interface regardless of aging, and thus the impact force was stable upon aging at 423 K for 500 h. For the Sn-9Zn joint, fracture mode changed from solder fracture to other fracture upon aging and thus this change led a decrease in the impact force. In the Sn-9Zn joint with an electroless Ni/Au plated electrode, fracture occurred in the solder regardless of aging, and thus impact properties improved compared with the joint using the Cu electrode. The impact properties are superior to those of the Sn-3Ag-0.5Cu joints with the Cu and the electroless Ni/Au electrodes.

Effect of Cooling Rate on Intermetallic Compounds Formation in Sn-Ag-Cu-In Solder

2018 ◽  
Vol 941 ◽  
pp. 2075-2080
Author(s):  
Kenji Miki ◽  
Tatsuya Kobayashi ◽  
Ikuo Shohji ◽  
Yusuke Nakata
Keyword(s):  
Solder Joint ◽  
Cooling Rate ◽  
Shear Force ◽  
Bonding Temperature ◽  
Lead Free ◽  
Joint Interface ◽  
Lead Free Solder ◽  
Vacuum Atmosphere ◽  
Free Solder ◽  
Large Formation

The effect of the cooling rate in bonding on IMCs formation and their morphology in the solder joint with Sn-3.0Ag-0.7Cu-5.0In (mass%) lead-free solder was investigated. As the substrate, the Cu plate and the Cu plate with electroplated Ni were prepared. Bonding was conducted in the vacuum atmosphere, and bonding temperature and time were 300°C and 10 minutes, respectively. The cooling rates in the bonding were changed from 0.02°C/s to 0.2°C/s. In both Cu/Cu and Cu/Ni joints, scallop-shaped IMCs form at the joint interfaces regardless of the cooling rate. In the Cu/Cu joint, Cu6(Sn,In)5 and Cu3(Sn,In) layers form at the joint interface. In the Cu/Ni joint, (Cu,Ni)6(Sn,In)5 and (Cu,Ni)3(Sn,In) layers form at the joint interface with Cu and the (Cu,Ni)6(Sn,In)5 layer forms at the joint interface with Ni. Die shear force of the Cu/Ni joints are a little larger than those of the Cu/Cu joints. Fracture occurs in the boundary between the scallop-shaped layer or the granular IMC layer and the layered IMC in both joints. The cooling rate from the peak temperature to solidification is an important factor to decide the shape of formed IMC. When the cooling rate is high and supercooling becomes large, formation of pillar-shaped IMCs occurs easily.

Influence of Content of Ni and Ag on Microstructure and Joint Strength of Lead-Free Solder Joint with Sn-Ag-Cu-Ni-Ge

2007 ◽  
Vol 353-358 ◽  
pp. 2033-2036 ◽  
Author(s):  
Ikuo Shohji ◽  
Satoshi Tsunoda ◽  
Hirohiko Watanabe ◽  
Tatsuhiko Asai
Keyword(s):  
Reaction Layer ◽  
Joint Strength ◽  
Heat Exposure ◽  
Layer Growth ◽  
Lead Free ◽  
Joint Interface ◽  
Lead Free Solder ◽  
Free Solder ◽  
Kinetics Of ◽  
Soldered Joint

An influence of content of Ni and Ag in a Sn-Ag-Cu-Ni-Ge lead-free solder has been investigated on microstructure and joint strength of the soldered joint under heat exposure conditions. The growth kinetics of the reaction layer formed at the joint interface has been investigated, and the apparent activation energy of the reaction layer growth has been also examined. Moreover, the soldered joints with Sn-Ag and Sn-Ag-Cu solders were prepared and were compared with the joints with the Sn-Ag-Cu-Ni-Ge solders.

Thermal Shock and Drop Test Behaviour of Area Array Packages in Forward and Backward Compatible Assemblies

2009 ◽  
Author(s):  
Bankeem V. Chheda ◽  
Sathishkumar Sakthivelan ◽  
S. Manian Ramkumar ◽  
Reza Ghaffarian
Keyword(s):  
Solder Ball ◽  
Lead Free ◽  
Lead Free Solder ◽  
Mechanical Shock ◽  
Lead Frame ◽  
Shock Test ◽  
Area Array ◽  
Snpb Solder ◽  
Solder Balls ◽  
Free Solder

With lead-free implementation it is important to examine the behaviour of the solder joint at the component level and at the board level. Assembly related issues along with component reliability are the main focus of this experimental research. This experimental study aims to evaluate the mechanical integrity of solder joints comprising of both lead-free and SnPb alloys. Lead-free and SnPb solder pastes were used to assemble the components. This will allow us to check the forward and the backward compatibility of the solder alloys. The test vehicle considered for this study contained a variety of components such as ultra chip scale package (UCSP192), package on package (PoP), plastic ball grid array (PBGA-676 & 1156), very thin chip array BGA (CVBGA432), thin small outline package (TSOP-40 & 48), dual row micro-lead frame (DRMLF), micro-lead frame (MLF-36 & 72), and chip resistors (0201, 0402, 0603). The scope of this paper is limited to the performance evaluation for area array packages only. Solder ball alloy for the area array packages included SAC 305, SAC405, SAC105, SnAg and SnPb. Three different PCB surface finishes, electroless nickel immersion gold (ENIG), SnPb hot air solder level (HASL), and immersion silver (ImAg) were used. Different solder ball alloys and surface finish combinations provided good comparison data for investigating the assembly performance. The PCB assemblies were subjected to mechanical shock test in the as-soldered condition and also after 200 and 500 thermal shock cycles at −55 to 125°C. For the mechanical shock test, the assemblies were subjected to 30 drops from a height of 3 ft, generating an average G force of 485N. After each drop the components were checked for the continuity of the total daisy chain. The number of drops for the first failure was used in analyzing the performance of the components for various combinations. Since each component had many independent daisy chains, the failure of the individual daisy chains was later used in determining the location of the failure and how it progressed. Two sets of test vehicles were assembled. One set comprised of components with lead-free solder balls of different composition (SAC305, SAC405, SAC105, SnAg) and the other set comprised of components with lead-free solder balls and SnPb solder balls (SAC305, SAC405, SnPb). This mix of alloy composition provided adequate data for comparison. It was critical to optimize the process in order to enable the melting of the mix of alloys. The area array package performance was evaluated when assembled with lead-free and SnPb solder paste. Some of the assemblies were cross-sectioned after the tests and the microstructure of the solder joint was analyzed to study the possible cause for assembly failure.

Effect of Added Elements on Microstructures and Joint Strength of Lead-Free Sn-Based Solder Joint Dispersed IMC Pillar

2016 ◽  
Vol 879 ◽  
pp. 2216-2221 ◽  
Author(s):  
Yawara Hayashi ◽  
Ikuo Shohji ◽  
Yusuke Nakata ◽  
Tomihito Hashimoto
Keyword(s):  
Solder Joint ◽  
Shear Force ◽  
Joint Strength ◽  
High Reliability ◽  
Bonding Time ◽  
Lead Free ◽  
Joint Interface ◽  
Lead Free Solder ◽  
Uniform Dispersion ◽  
Free Solder

To create a high reliability solder joint using IMCs dispersed in the joint, the joints with four types of lead-free solder were investigated. The joint with Sn-3.0Ag-0.7Cu-5.0In (mass%) has high die shear force compared to other joints investigated, and the joint with the Ni-electroplated Cu bonded at 300 oC for 30 min showed the maximum die shear force due to formation of a large number of fine IMCs. In the joint with Sn-0.7Cu-0.05Ni (mass%), uniform dispersion of a large number of IMCs was achieved, although the die shear force of the joint is lower than that of the joint with Sn-3.0Ag-0.7Cu-5.0In. In the joint with Sn-5.0Sb (mass%), a solder area was remained in the center of the joint although a large number of columnar IMCs form at the joint interface. The die shear force of the joint with Sn-5.0Sb increased with increasing the bonding time due to formation and growth of IMCs. In the joint with Sn-3.0Ag-0.5Cu (mass%), IMCs formed at the joint interface and did not disperse in the entire joint.

The micro-impact fracture behavior of lead-free solder ball joints

2008 ◽  
Vol 23 (4) ◽  
pp. 1057-1063 ◽  
Author(s):  
Y.L. Huang ◽  
K.L. Lin ◽  
D.S. Liu
Keyword(s):  
Solder Joint ◽  
Fracture Energy ◽  
Fracture Behavior ◽  
Solder Ball ◽  
Impact Fracture ◽  
Lead Free ◽  
Lead Free Solder ◽  
Impact Fracture Behavior ◽  
Free Solder ◽  
Ball Joints

The present study investigated the micro-impact fracture behavior of various lead-free solder joints, including Sn–1Ag–0.1Cu–0.02Ni–0.05In, Sn–1.2Ag–0.5Cu–0.05Ni, and Sn–1Ag–0.5Cu. The fracture that occurs within the solder joint corresponds to a higher impact fracture energy (1.35 mJ), while the fracture at the interface between the solder joint and intermetallic compound acquires a smaller impact energy (0.82 mJ). Two types of fracture mechanisms were proposed based on observations of the fracture morphology and the impact curve for the solder ball joints. The longer deflection distance, referring to better elongation, exists for the mechanism corresponding to the higher fracture energy.

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