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.

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.

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.

Study on the Mechanical Bend Fatigue of Micro-Joining Soldered Joint with Lead-Free Solder

2007 ◽  
Vol 353-358 ◽  
pp. 2573-2576 ◽  
Author(s):  
Fang Juan Qi ◽  
Li Xing Huo ◽  
Ya Ping Ding ◽  
Zhan Lai Ding
Keyword(s):  
Solder Joint ◽  
Failure Modes ◽  
Lead Free ◽  
Joint Interface ◽  
Similar Data ◽  
Lead Free Solder ◽  
Fatigue Reliability ◽  
Free Solder ◽  
Halogen Free ◽  
Soldered Joint

In recent years, several electronics manufacturers have been working toward introducing lead-free solder and halogen-free print circuit boards (PCBs) into their products. The key drivers for the change in materials have been the impending environmental legislations, particularly in Europe and Japan as well as the market appeal of ‘green’ products. The reliability of the new materials is an important determinant of the pace of adoption. Fairly extensive mechanical fatigue reliability data is also available for micro-joining soldered joint such as Ball Grid Array (BGA) with tin-lead solder. However, similar data is not available for BGAs assembled with lead-free solder. Mechanical reliability is a critical indicator for phone and BGA survival during repeated keypress, and to some extent during drop. In this paper, the mechanical bend fatigue of BGAs with tin-lead and lead-free solders on halogen-free substrates are examined respectively. A tin-silver-copper alloy was used as lead-free solder due to its increasing acceptance, and the results were compared to those from samples assembled with Sn63Pb37 solder. The reliability was examined at both low cycle and high cycle fatigue. Results show that the mechanical bend fatigue reliability of BGA assemblies with lead-free solder is higher than that of BGA assembly with tin-lead solder. Cross section and failure analysis indicated two distinct failure modes - solder joint and PCB failure. A 3-D parametric finite element model was developed to correlate the local PCB strains and solder joint plastic strains with the fatigue life of the assembly. The intermetallic compoumd (IMC) of micro-joining joint interface was analysised in the future in order to study on the effect of IMC on the reliability.

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.

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.

scholarly journals Evaluation of Thin Copper Wire and Lead-Free Solder Joint Strength by Pullout Tests and Wire Surface Observation

Crystals ◽  
2017 ◽  
Vol 7 (8) ◽  
pp. 255 ◽  
Author(s):  
Naoya Tada ◽  
Takuhiro Tanaka ◽  
Takeshi Uemori ◽  
Toshiya Nakata
Keyword(s):  
Solder Joint ◽  
Joint Strength ◽  
Copper Wire ◽  
Lead Free ◽  
Lead Free Solder ◽  
Wire Surface ◽  
Surface Observation ◽  
Pullout Tests ◽  
Free Solder
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