Solder joints properties as function of multiple reflow Vapor Phase Soldering process

Abstract Both the number and the variants of ball grid array packages (BGAs) are tending to increase on network printed board assemblies with sizes ranging from a few millimeter die size wafer level packages with low ball count to large multidie system-in-package (SiP) BGAs with 60–70 mm side lengths and thousands of I/Os. One big challenge, especially for large BGAs, SiPs, and for thin fine-pitch BGA assemblies, is the dynamic warpage during the reflow soldering process. This warpage could lead to solder balls losing contact with the solder paste and its flux during parts of the soldering process, and this may result in solder joints with irregular shapes, indicating poor or no coalescence between the added solder and the BGA balls. This defect is called head-on-pillow (HoP) and is a failure type that is difficult to determine. In this study, x-ray inspection was used as a first step to find deliberately induced HoP defects, followed by prying off of the BGAs to verify real HoP defects and the fault detection correlation between the two methods. The result clearly shows that many of the solder joints classified as potential HoP defects in the x-ray analysis have no evidence at all of HoP after pry-off. This illustrates the difficulty of determining where to draw the line between pass and fail for HoP defects when using x-ray inspection.

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Effects of Vapor Phase Soldering on the Properties of Piezoceramic Materials

Additional Conferences (Device Packaging HiTEC HiTEN & CICMT) ◽

10.4071/cicmt-2012-tha24 ◽

2012 ◽

Vol 2012 (CICMT) ◽

pp. 000603-000605

Author(s):

Silke Bramlage ◽

Klaus-Jürgen Wolter

Keyword(s):

Heat Treatment ◽

Vapor Phase ◽

Lead Zirconate Titanate ◽

Piezoelectric Properties ◽

Lead Zirconate ◽

Type I ◽

Soldering Process ◽

Before And After ◽

Curie Temperatures ◽

Piezoelectric Charge

Eight different PZT (lead zirconate titanate) materials (Navy Type I and II) with Curie temperatures between 250 °C and 350 °C were subjected to a standard vapor phase soldering process with a peak temperature of 240 °C for three cycles. As indicators for the depolarization, the piezoelectric charge coefficient (d33) and the coupling coefficient (keff) were measured both before and after each heat treatment. Our studies demonstrate reductions in piezoelectric properties between 5% and 20%, depending on the Curie temperature of the corresponding material. The effects of the second and third cycle were minimal. The drop in performance, especially for materials with higher Curie temperatures, is moderate, and can be accounted for in the design of the device. Thus batch soldering processes become a viable alternative to selective soldering.

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Electromigration behavior of Cu/Sn–58Bi–1Ag/Cu solder joints by ultrasonic soldering process

Journal of Materials Science Materials in Electronics ◽

10.1007/s10854-020-03817-6 ◽

2020 ◽

Vol 31 (15) ◽

pp. 11997-12003

Author(s):

Shengfa Liu ◽

Zhangyang Liu ◽

Li Liu ◽

Tianjie Song ◽

Wei Liu ◽

...

Keyword(s):

Solder Joints ◽

Soldering Process ◽

Ultrasonic Soldering

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Thermo-mechanical challenges of reflowed lead-free solder joints in surface mount components: a review

Soldering & Surface Mount Technology ◽

10.1108/ssmt-10-2015-0032 ◽

2016 ◽

Vol 28 (2) ◽

pp. 41-62 ◽

Cited By ~ 22

Author(s):

Chun Sean Lau ◽

C.Y. Khor ◽

D. Soares ◽

J.C. Teixeira ◽

M.Z. Abdullah

Keyword(s):

Solder Joints ◽

Simulation Modelling ◽

Lead Free ◽

Lead Free Solder ◽

Reflow Process ◽

Reflow Soldering ◽

Content Type ◽

Surface Mount ◽

Soldering Process ◽

Free Solder

Purpose The purpose of the present study was to review the thermo-mechanical challenges of reflowed lead-free solder joints in surface mount components (SMCs). The topics of the review include challenges in modelling of the reflow soldering process, optimization and the future challenges in the reflow soldering process. Besides, the numerical approach of lead-free solder reliability is also discussed. Design/methodology/approach Lead-free reflow soldering is one of the most significant processes in the development of surface mount technology, especially toward the miniaturization of the advanced SMCs package. The challenges lead to more complex thermal responses when the PCB assembly passes through the reflow oven. The virtual modelling tools facilitate the modelling and simulation of the lead-free reflow process, which provide more data and clear visualization on the particular process. Findings With the growing trend of computer power and software capability, the multidisciplinary simulation, such as the temperature and thermal stress of lead-free SMCs, under the influenced of a specific process atmosphere can be provided. A simulation modelling technique for the thermal response and flow field prediction of a reflow process is cost-effective and has greatly helped the engineer to eliminate guesswork. Besides, simulated-based optimization methods of the reflow process have gained popularity because of them being economical and have reduced time-consumption, and these provide more information compared to the experimental hardware. The advantages and disadvantages of the simulation modelling in the reflow soldering process are also briefly discussed. Practical implications This literature review provides the engineers and researchers with a profound understanding of the thermo-mechanical challenges of reflowed lead-free solder joints in SMCs and the challenges of simulation modelling in the reflow process. Originality/value The unique challenges in solder joint reliability, and direction of future research in reflow process were identified to clarify the solutions to solve lead-free reliability issues in the electronics manufacturing industry.

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Thermophysical Properties in Assembling Process at Macro and Micro Level

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1114.172 ◽

2015 ◽

Vol 1114 ◽

pp. 172-179 ◽

Cited By ~ 1

Author(s):

Mihai Branzei ◽

Ioan Plotog

Keyword(s):

Thermophysical Properties ◽

Structural Model ◽

Solder Joints ◽

Dielectric Substrate ◽

Mechanical And Thermal Properties ◽

Metallic Surfaces ◽

Electronic Components ◽

Soldering Process ◽

Micro Level ◽

Input Variables

The electronic modules are complex ensemble of electronic components having terminals (PIN) connected by solder joints on dedicated metallic surfaces (PAD) parts of conductive interconnection structure realized on rigid or flexible dielectric substrate having different core materials. The reliability of the electronic modules could be considered as expression of solder joints functionality (SJF) relating to working conditions and unique defined by their electrical, mechanical and thermal properties. These properties are in close connection with the solder joints microstructures, result of the soldering Process temperature gradient action over the trinomial solder alloy Paste, Pin and Pad. Consequently the solder joints quality can be correctly evaluated taking into consideration not only the severally intrinsic parameters of the trinomial elements Pin-Pad-Paste characterized by specific thermophysical properties (ThP), but also interrelate the complex reaction at the interface between them and interdependence with the soldering Process parameters.In the paper, will be analyzed the influencing factors of manufacturing processes, the most important assembling defects at macro and micro level, their causes relating to specific ThP and processes at interfaces Pin-solder joints-Pad, it will be identify the Key Process Input Variables (KPIV) and propose a structural model for assembling processes, 4P Soldering Model, as an useful tool in engineering of electronic product in order to assure the assumed goal for assembling stage.

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Mechanical reliability of solder joints in PCBs assembled in surface mount technology

Soldering & Surface Mount Technology ◽

10.1108/ssmt-10-2015-0037 ◽

2016 ◽

Vol 28 (1) ◽

pp. 18-26 ◽

Cited By ~ 4

Author(s):

Janusz Borecki ◽

Tomasz Serzysko

Keyword(s):

Mechanical Strength ◽

Shear Force ◽

Printed Circuit Boards ◽

Solder Joints ◽

Electronic Device ◽

Operating Conditions ◽

Content Type ◽

Operational Conditions ◽

Soldering Process ◽

The Individual

Purpose – The purpose of this paper is to determine the dependence of mechanical strength of solder joints on printed circuit boards from the soldering process parameters and operating conditions of the electronic device. Design/methodology/approach – The research was performed using the Taguchi method of planning of experiments. Evaluation of the quality of solder joints was made on the basis of microscopic observations, X-ray analysis and measurements of shear force of solder joints. Findings – The carried out research has shown the influence of the individual parameters of the soldering process on the mechanical strength of solder joints and the mechanism of damage of solder joints under the influence of shear force. Originality/value – The authors present results of their research using advanced techniques of experimental design and analysis of results. In this study, original approach was used to simulate the operational conditions of electronic devices including thermal imaging technology.

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An Investigation of the Lead-Free Surface Mount Soldering Process: Solder Joint Evaluation and Process Optimisation

Electronic and Photonic Packaging, Electrical Systems Design and Photonics, and Nanotechnology ◽

10.1115/imece2004-60491 ◽

2004 ◽

Author(s):

Claire Ryan ◽

Jeff M. Punch ◽

Bryan Rodgers ◽

Greg Heaslip ◽

Shane O’Neill ◽

...

Keyword(s):

Screen Printing ◽

Solder Joints ◽

Lead Free ◽

Lead Free Solder ◽

Solder Paste ◽

Surface Mount ◽

Snagcu Solder ◽

Soldering Process ◽

Free Process ◽

Free Solder

A European Union ban on lead in most electrical and electronic equipment will be imposed as of July 1st 2006. The ban, along with market pressures, means that manufacturers must transfer from a tin-lead soldering process to a lead-free process. In this paper the implications on the surface mount (SMT) soldering process are presented. A set of experiments was conducted to investigate the screen-printing and reflow steps of the SMT process using a tin-silver-copper (95.5Sn3.8Ag0.7Cu) solder and a baseline of standard tin-lead (63Sn37Pb). 10×10 arrays of micro Ball Grid Array (micro-BGA) components mounted on 8-layer FR4 printed wiring boards (PWBs) were used. The screen-printing experiment addressed the deposition of the solder paste on the board. The parameters used in the investigation were print speed, squeegee pressure, snap-off distance, separation speed and cleaning interval, with the responses being measurements of paste height and volume. Optimum screen-printer settings were determined which give adequate paste volume and height and a good print definition. The reflow experiment investigated the following parameters of the temperature profile: preheat, soak, peak and cool down temperatures, and conveyor speed. The resulting solder joints were evaluated using cross-section analysis and x-ray techniques in order to determine the presence of defects. A mechanical fatigue test was also carried out in order to compare the strength of the solder joints. The overall quality of the lead-free solder joints was determined from these tests and compared to that of tin-lead. The outcome is a set of manufacturing guidelines for transferring to lead-free solder including optimum screen-printer and reflow oven settings for use with an SnAgCu solder.

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Solder joint quality evaluation based on heating factor

Circuit World ◽

10.1108/cw-10-2017-0059 ◽

2018 ◽

Vol 44 (1) ◽

pp. 37-44 ◽

Cited By ~ 21

Author(s):

Petr Veselý ◽

Eva Horynová ◽

Jiří Starý ◽

David Bušek ◽

Karel Dušek ◽

...

Keyword(s):

Shear Strength ◽

Solder Alloy ◽

Isothermal Aging ◽

Solder Joints ◽

Strength Increase ◽

Technological Parameters ◽

Content Type ◽

Soldering Process ◽

Before And After ◽

Joint Quality

Purpose The purpose of this paper is to increase the reliability of manufactured electronics and to reveal reliability significant factors. The experiments were focused especially on the influence of the reflow oven parameters presented by a heating factor. Design/methodology/approach The shear strength of the surface mount device (SMD) resistors and their joint resistance were analyzed. The resistors were assembled with two Sn/Ag/Cu-based and one Bi-based solder pastes, and the analysis was done for several values of the heating factor and before and after isothermal aging. The measurement of thickness of intermetallic compounds was conducted on the micro-sections of the solder joints. Findings The shear strength of solder joints based on the Sn/Ag/Cu-based solder alloy started to decline after the heating factor reached the value of 500 s · K, whereas the shear strength of the solder alloy based on the Bi alloy (in the measured range) always increased with an increase in the heating factor. Also, the Bi-based solder joints showed shear strength increase after isothermal aging in contrast to Sn/Ag/Cu-based solder joints, which showed shear strength decrease. Originality/value The interpretation of the results of such a comprehensive measurement leads to a better understanding of the mutual relation between reliability and other technological parameters such as solder alloy type, surface finish and parameters of the soldering process.

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