Influence of Second Reflow on the Intermetallic Compound Growth with Different Surface Finish

The formation and growth of the intermetallic were frequently discussed since lead free solder took place replacing the lead solder. However, the effect of multiple reflow process on the intermetallic morphology that was subjected to aging still needs further investigation. Thus, this study aimed to investigate the effect of second reflow towards the intermetallic compound formation and growth. Two types of surface finishes were used such as Immersion Tin (ImSn) and Electroless Nickel Immersion Gold (ENIG). Both test boards were reflowed once with Sn-3Ag-0.5Cu at the temperature of 225 °C and soaking for 8 seconds. Then, they were reflowed again at the same temperature for 25 minutes prior to an isothermal aging process for 250, 500, 1000 and 2000 hours at the temperature of 150 °C. The ProgRes C3 IM7200 Optical Microscope and ImageJ were used for the microstructural study, which includes morphology and thickness. Results indicated that IMC thickness formed between solder and ImSn surface finish increased significantly with 1.28 µm incremental when exposed to the second reflow. Whereas the IMC thickness of ENIG surface finish was increased for up to 0.15 µm. In addition, ENIG showed higher activation energy as compared to ImSn.

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Effect of Blast Wave on Intermetallics Formation, Hardness and Reduced Modulus Properties of Solder Joints

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.307.31 ◽

2020 ◽

Vol 307 ◽

pp. 31-36

Author(s):

Nur Shafiqa Safee ◽

Wan Yusmawati Wan Yusoff ◽

Ariffin Ismail ◽

Norliza Ismail ◽

Maria Abu Bakar ◽

...

Keyword(s):

Surface Finish ◽

Test Performance ◽

Printed Circuit Board ◽

Microstructural Analysis ◽

Electroless Nickel ◽

Optical Microscope ◽

Circuit Board ◽

Reduced Modulus ◽

Free Solder ◽

Tin Silver Copper

Tin-Silver-Copper (SnAgCu) lead-free solder on Electroless Nickel Immersion Gold (ENiG) and Immersion Tin (ImSn) surface finish printed circuit board was subjected to blast test. A variation of intermetallic compounds (IMC) layer, hardness and reduced modulus of soldered sample exposed to blast test were intensively investigated using optical microscope and nanoindentation machine. Formation of IMCs due to reaction between solder and substrate during blast test provided deleterious effect of metallurgical bond strength and reliability on the solder joint. Microstructural analysis was evaluated via Infinite Focused Microscope (IFM). The findings of these studies indicate that best surface finished for blast test performance was not necessarily the best surface finish for optimum reliability. ENiG and ImSn surface finish can be advantage or a disadvantage depending on the application, package and reliability requirements. As a result, most component assemblers are using ENiG and ImSn in order to improve solderability as well as the wettability between solder and the substrate and to meet various package requirements.

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Reliability Analysis of Lead-Free Solder Joints with Solder Doping on Harsh Environment

International Symposium on Microelectronics ◽

10.4071/isom-2016-tp54 ◽

2016 ◽

Vol 2016 (1) ◽

pp. 000117-000122 ◽

Cited By ~ 8

Author(s):

Cong Zhao ◽

Thomas Sanders ◽

Zhou Hai ◽

Chaobo Shen ◽

John L. Evans

Keyword(s):

Surface Finish ◽

Isothermal Aging ◽

Electroless Nickel ◽

Lead Free ◽

Lead Free Solder ◽

Solder Paste ◽

Surface Mount ◽

Surface Finishes ◽

Free Solder ◽

Immersion Silver

Abstract This paper investigates the effect of long term isothermal aging and thermal cycling on the reliability of lead-free solder mixes with different solder compositions, PCB surface finishes, and isothermal aging conditions. A variety of surface mount components are considered, including ball grid arrays (BGAs), quad flat no-lead packages (QFNs) and 2512 Surface Mount Resistors (SMRs). 12 lead-free solder pastes are tested; for BGA packages these are reflowed with lead-free solder spheres of SAC105, SAC305 and matched doped solder spheres (“matched” solder paste and sphere composition). Three surface finishes are tested: Organic Solderability Preservative (OSP), Immersion Silver (ImAg), and Electroless Nickel Immersion Gold (ENIG). All test components are subjected to isothermal aging at 125°C for 0 or 12 months, followed by accelerated thermal cycle testing from −40°C to 125°C. Data from the first 1500 cycles is presented here, with a focus on the effect of surface finish on package reliability. Current results demonstrate that the choice of surface finish has a strong effect on reliability. However, different solder materials appear to show different reliability trends with respect to the surface finishes, and the reliability trends of BGA and SMR packages also diverge.

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Influence of Bi Addition on Wettability and Mechanical Properties of Sn-0.7Cu Solder Alloy

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.273.27 ◽

2018 ◽

Vol 273 ◽

pp. 27-33 ◽

Cited By ~ 3

Author(s):

Mohd Izrul Izwan Ramli ◽

M.S.S. Yusof ◽

Mohd Arif Anuar Mohd Salleh ◽

Rita Mohd Said ◽

Kazuhiro Nogita

Keyword(s):

Mechanical Properties ◽

Intermetallic Compound ◽

Lead Free Solder ◽

Compound Formation ◽

Alloying Additions ◽

Wetting Properties ◽

Intermetallic Compound Formation ◽

Interfacial Intermetallic Compound ◽

Free Solder ◽

Intermetallic Layers

The effect of bismuth (Bi) micro-alloying additions on wettability and mechanical properties of Sn-0.7Cu lead-free solder were explored. This paper also investigates the influences of various Bi percentages on the suppression of intermetallic compound formation. Scanning electron microscope (SEM) was used to observe the microstructure evolution of solder joint including the thickness of interfacial intermetallic layers. Overall, with the addition of Bi to Sn-0.7Cu solder, the size of primary Cu6Sn5become smaller and suppresses the thickness of interfacial intermetallic compound between solder and the Cu substrate. Microhardness value and wetting properties also increased with Bi addition which resulted in smaller size of β-Sn and Cu6Sn5.

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Intermetallic compound formation in Sn-Co-Cu, Sn-Ag-Cu and eutectic Sn-Cu solder joints on electroless Ni(P) immersion au surface finish after reflow soldering

Conference on High Density Microsystem Design and Packaging and Component Failure Analysis, 2006. HDP'06. ◽

10.1109/hdp.2006.1707608 ◽

2006 ◽

Author(s):

Peng Sun ◽

C. Andersson ◽

Xicheng Wei ◽

Zhaonian Cheng ◽

Dongkai Shangguan ◽

...

Keyword(s):

Intermetallic Compound ◽

Surface Finish ◽

Solder Joints ◽

Compound Formation ◽

Reflow Soldering ◽

Intermetallic Compound Formation ◽

Electroless Ni

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Enhancement on wettability and intermetallic compound formation with an addition of Al on Sn-0.7Cu lead-free solder fabricated via powder metallurgy method

10.1063/1.4958777 ◽

2016 ◽

Author(s):

Nisrin Adli ◽

Nurul Razliana Abdul Razak ◽

Norainiza Saud

Keyword(s):

Powder Metallurgy ◽

Intermetallic Compound ◽

Lead Free ◽

Powder Metallurgy Method ◽

Lead Free Solder ◽

Compound Formation ◽

Intermetallic Compound Formation ◽

Free Solder

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Effect of Immersion Coating Deposition Time on Solder Joint Properties

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1133.361 ◽

2016 ◽

Vol 1133 ◽

pp. 361-365

Author(s):

Zetty Akhtar Abd Malek ◽

Hardinna Wirda Kahar ◽

Siti Rabiatull Aisha Idris ◽

Mahadzir Ishak

Keyword(s):

Intermetallic Compound ◽

Solder Joint ◽

Cross Sections ◽

Surface Finish ◽

Deposition Time ◽

Industrial Area ◽

Optical Microscope ◽

Influential Factor ◽

Surface Finishes ◽

Immersion Plating

Surface finishes on copper pads have been known to be one of influential factor in the solder joint quality. This due to the difference in interfacial reaction and intermetallic compound formation on solder pad was strongly influence by the type of surface finishes. Deposition times during immersion plating process on copper pads are important as the thickness of coating will decide several properties of surface finish, such as wettability during soldering process. Thus, this study aims to investigate the effect of deposition time of immersion gold coating on wettability of the surface finish and how it affect the formation of intermetallic compounds on solder joint. In this works, deposition time of copper pads in immersion gold solution were varied from 3 minutes up to 15 minutes. The thickness of immersion gold layer that form on Cu pads were then measured using Scanning Electron Microscopy (SEM). As the main objective of this study is to study the effect of deposition time during immersion plating process towards solder joint, the pads were reflowed along with Sn-3.0Ag-0.5Cu solder in furnace under temperature 250 °C for 25 minutes. Then, the cross sections of the solder joints were examined using optical microscope in order to measure the wetting angle and thickness of intermetallic compound formed; which acceptable value in industrial area, should be below 40 ̊ and below 4μm as reflow respectively.

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