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

2016 ◽  
Vol 2016 (1) ◽  
pp. 000117-000122 ◽  
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.

Effect of Soldier Bump Size On Interfacial Reactions During Soldering Between PB–Free Solder and Cu and Cu Ni/Pd/Au Surface Finishes

2012 ◽  
Author(s):  
Nor Akmal Fadil ◽  
Ali Ourdjini ◽  
Azmah Hanim Mohamed Ariff ◽  
Siti Rabiatul Aisha Idris
Keyword(s):  
Intermetallic Compounds ◽  
Surface Finish ◽  
Isothermal Aging ◽  
Flip Chip ◽  
Electroless Nickel ◽  
Lead Free ◽  
Lead Free Solder ◽  
Under Bump Metallization ◽  
Surface Finishes ◽  
Free Solder

Teknologi flip chip memberikan ketumpatan I/O yang sangat tinggi dan mengambil kira prestasi elektrikal yang paling baik dalam penyambungan komponen elektronik. Oleh itu, kajian tentang sebatian antara logam dilaksanakan untuk mengkaji kesan saiz bebola pateri bagi beberapa penyudahan permukaan, iaitu Kuprum dan Nikel tanpa elektrod/Palladium tanpa elektrod/Emas rendaman (ENEPIG). Pelogaman di bawah pateri (UBM) Ni/Pd/Au bagi aplikasi flip chip digunakan dengan sangat meluas dalam pembungkusan elektronik. Analisis FESEM dilakukan untuk menganalisis morfologi dan komposisi bagi sebatian antara logam (IMC). IMC yang terbentuk antara pateri Sn–Pb dan tanpa Pb dengan penyudahan permukaan kuprum semasa proses pematrian logam secara umumnya adalah (Cu, Ni)6Sn5 dan Cu6Sn5 dan Cu6Sn5. Sementara IMC utama yang terbentuk antara pateri Sn–Pb dan tanpa Pb dengan penyudahan permukaan ENEPIG adalah (Ni, Cu)3Sn4 dan Ni3Sn4. Hasil daripada analisis morfologi menggunakan FESEM dengan EDX menyatakan penuaan sesuhu pada suhu 150°C menyebabkan penebalan dan pengasaran struktur IMC serta menjadikan bentuknya kepada lebih sfera. Tebal IMC bagi kedua–dua penyudahan yang dikaji adalah lebih tinggi bagi bebola patri yang lebih kecil. Daripada hasil kajian juga, didapati bahawa kadar pertumbuhan IMC adalah lebih tinggi apabila pematrian dilakukan atas penyudahan kuprum berbanding ENEPIG. Hasil kajian juga menunjukkan ketebalan IMC adalah berkadaran dengan masa penuaan sesuhu. Kata kunci: Flip chip; Kumprum dan Nikel tanpa elektrod; Palladium tanpa elektrod; Emas rendaman (ENEPIG); Pelogaman di bawah pateri (UMB) Ni/Pd/Au Flip chip technology provides the ultimate in high I/O–density and count with superior electrical performance for interconnecting electronic components. Therefore, the study of the intermetallic compounds was conducted to investigate the effect of solder bumps sizes on several surface finishes which are copper and Electroless Nickel/Electroless Palladium/Immersion Gold (ENEPIG) which is widely used in electronics packaging as under–bump metallization (UBM) for flip–chip application nowadays. In this research, field emission scanning electron microscopy (FE–SEM) analyses were conducted to analyze the morphology and composition of intermetallic compounds (IMCs) formed at the interface between the solder and UBM. The IMCs between Sn–Pb and lead–free solder with Cu surface finish during reflowing were mainly (Cu, Ni)6Sn5 dan Cu6Sn5. While the main IMCs formed between Sn–Pb and lead–free solder on ENEPIG surface finish are (Ni, Cu)3Sn4 and Ni3Sn4. The results from FESEM with energy dispersive x–ray (EDX) have revealed that isothermal aging at 150°C has caused the thickening and coarsening of IMCs as well as changing them into more spherical shape. The thickness of the intermetallic compounds in both finishes investigated ware found to be higher in solders with smaller bump size. From the experimental results, it also appears that the growth rate of IMCs is higher when soldering on copper compared to ENEPIG finish. Besides that, the results also showed that the thickness of intermetallic compounds was found to be proportional to isothermal aging duration. Key words: Electroless nickel; electroless palladium; immersion gold (ENEPIG); flip chip; Ni/Pd/Au Under–bump metallization (UMB)

Practical Application and Analysis of Lead-Free Solder on Chip-On-Flip-Chip SiP for Hearing Aids

2017 ◽  
Vol 2017 (1) ◽  
pp. 000201-000207 ◽  
Author(s):  
Youngtak Lee ◽  
Doug Link
Keyword(s):  
Hearing Aids ◽  
Flip Chip ◽  
Failure Modes ◽  
Lead Free ◽  
Lead Free Solder ◽  
Solder Paste ◽  
Practical Application ◽  
Surface Mount ◽  
Free Solder ◽  
On Chip

Abstract Due to rapid growth of the microelectronics industry, packaged devices with small form factors, low costs, high power performance, and increased efficiency have become of high demand in the market. To realize the current market development trend, flip chip interconnection and System-in-Package (SiP) are some of the promising packaging solutions developed. However, a surprising amount of surface mount technology (SMT) defects are associated with the use of lead-free solder paste and methods by which the paste is applied. Two such defects are solder extrusion and tombstoning. Considerable amount of defects associated with solder overflow are found on chip-on-flip-chip (COFC) SiP in hearing aids. Through the use of design of experiments (DOE), lead-free solder defect causes on hearing aids application can be better understood and subsequently reduced or eliminated. This paper will examine the failure modes of solder extrusion and tombstoning that occurred when two different types of lead-free solders, Sn-Ag-Cu (SAC) and BiAgX were used within a SiP for attachment of surface mount devices (SMD) chip components for hearing aid applications. The practical application and analysis of lead-free solder for hearing aids will include the comprehensive failure analysis of the SMD components and compare the modeling and analysis of the two different solder types through the DOE process.

Comparative Modeling and Analysis of Lead-Free Solder Extrusion for the Design of Reliability

2016 ◽  
Vol 2016 (1) ◽  
pp. 000111-000116
Author(s):  
Youngtak Lee ◽  
Doug Link
Keyword(s):  
Design Of Experiments ◽  
Flip Chip ◽  
Failure Modes ◽  
Form Factors ◽  
Lead Free ◽  
Lead Free Solder ◽  
Solder Paste ◽  
Modeling And Analysis ◽  
Surface Mount ◽  
Free Solder

Abstract Due to rapid growth of the microelectronics industry, packaged devices with small form factors, low costs, high power performance, and increased efficiency have become of high demand in the market. To realize the current market development trend, flip chip interconnection and System-in-Package (SiP) are some of the promising packaging solutions developed. However, a surprising amount of surface mount technology (SMT) defects are associated with the use of lead-free solder paste and methods by which the paste is applied. Two such defects are solder extrusion and tombstoning. Through the use of design of experiments (DOE), lead-free solder defect causes can be better understood and subsequently reduced or eliminated. This paper will examine the failure modes of solder extrusion and tombstoning that occurred when two different types of lead-free solders, Sn-Ag-Cu (SAC) and BiAgX were used within a SiP for attachment of surface mount devices (SMD) chip components. The systematic investigation will include the comprehensive failure analysis of the SMD components and compare the modeling and analysis of the two different solder types utilizing the design of experiments methods.

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

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.

Effect of Nickel Doping on Interfacial Reaction between Lead-Free Solder and Ni-P Substrate

2012 ◽  
Vol 488-489 ◽  
pp. 1375-1379 ◽  
Author(s):  
O. Saliza Azlina ◽  
A. Ourdjini ◽  
I. Siti Rabiatull Aisha
Keyword(s):  
Isothermal Aging ◽  
Environmental Concern ◽  
Aging Treatment ◽  
Electroless Nickel ◽  
Lead Free ◽  
Lead Free Solder ◽  
Reflow Soldering ◽  
Nickel Doping ◽  
Free Solder ◽  
Sac Solder

Due to environmental concern, lead-free solder are taking the place of eutectic Sn-Pb solder in electronic packaging industry. Among various lead free alloys, Sn–Ag–Cu (SAC) alloys are leading lead-free candidate solders for various applications because it is offered better properties. This study investigates the interfacial reactions during reflow soldering and isothermal aging between Sn-3.0Ag-0.5Cu (SAC305) and Sn-3.0Ag-0.5Cu-0.05Ni (SACN30505) on electroless nickel/ immersion palladium/immersion gold (ENEPIG) surface finish. The substrates were subjected to isothermal aging at 125°C for up to 2000 hours with solder size diameter of 500μm. The results indicated that after reflow soldering, (Cu, Ni)6Sn5 IMC is formed between solder and substrate while after aging treatment a new IMC was formed between (Cu, Ni)6Sn5 and substrate known as (Ni, Cu)3Sn4. Moreover, after soldering and isothermal aging, Ni-doped (SACN) solder represents a thicker IMC compared to SAC solder. Aging time of solder joints results in an increase of IMC’s thickness and changes their morphologies to become more spherical, dense and with larger grain size. In addition, the results also revealed that the thickness of intermetallics formed is proportional to the aging duration.

scholarly journals Effect of Isothermal Aging 2000 Hours on Intermetallics Formed between Ni-Pd-Au with Sn-4Ag-0.5Cu Solders

2013 ◽  
Vol 650 ◽  
pp. 194-199 ◽  
Author(s):  
M.A. Azmah Hanim ◽  
A. Ourdjini ◽  
I. Siti Rabiatul Aisha ◽  
O. Saliza Azlina
Keyword(s):  
Aging Time ◽  
Isothermal Aging ◽  
Growth Process ◽  
Electroless Nickel ◽  
Gold Surface ◽  
Lead Free ◽  
Lead Free Solder ◽  
Reflow Process ◽  
Dense Structure ◽  
Free Solder

The present study investigated the effect of isothermal aging up to 2000 hours on the intermetallics formed between Sn-4Ag-0.5Cu lead free solder on electroless nickel electroless palladium immersion gold surface finish (Ni-Pd-Au). For all parameters, aging have an effect of changing the intermetallic morphology to coarser and dense structure. The intermetallic compound formed for the interconnection of the lead free solder changes with increased aging time from (Cu,Ni)6Sn5 compound to (Ni,Cu)3Sn4. At the end of the 2000 hours aging time, it changes to Ni3Sn4. This is the effect of Cu element availability during the intermetallics growth process. Starting from as reflow process, (Pd, Ni)Sn4 intermetallics formed near the interface of the solder joint. The formation of the (Pd, Ni)Sn4 intermetallics act like a diffusion barrier to slow down the growth of interface intermetallics. Lastly, Au element was detected in the Pd-Sn based intermetallic after aging more than 1000 hours.

Effect of Different Aging Temperatures on Interfacial Reaction between SAC305 and ENEPIG Surface Finish

2011 ◽  
Vol 415-417 ◽  
pp. 1181-1185 ◽  
Author(s):  
Osman Saliza Azlina ◽  
Ali Ourdjini ◽  
Siti Rabiatull Aisha Idris ◽  
Mohd Ariff Azmah Hanim
Keyword(s):  
Isothermal Aging ◽  
Aging Treatment ◽  
Electroless Nickel ◽  
Lead Free ◽  
Green Product ◽  
Hazardous Substance ◽  
Lead Free Solder ◽  
Reflow Soldering ◽  
Packaging Industry ◽  
Free Solder

In electronic packaging industry, they are now driven technology to green product by replacing leaded-solder with lead-free solder in order to fulfill the European Restriction of Hazardous Substance (RoHS) compliance. Thus, Sn-Ag-Cu lead-free solder family is one of candidates can fulfill this requirement. This study investigates the interfacial reactions during reflow soldering and isothermal aging between Sn-3.0Ag-0.5Cu (SAC305) and electroless nickel/ immersion palladium/immersion gold (ENEPIG). Reliability of solder joint is also examined by performing solid state isothermal aging at 125°C and 150°C for up to 2000 hours. The results revealed that after reflow soldering, (Cu, Ni)6Sn5 IMC is formed between solder and substrate while after aging treatment another IMC was found between (Cu, Ni)6Sn5 and substrate known as (Ni, Cu)3Sn4. Aging time and temperature of solder joints results in an increase of IMC’s thickness and changes their morphologies to become more spherical, dense and with larger grain size. In addition, the results also revealed that the thickness of intermetallics formed is proportional to the aging duration and temperature.

Study of immersion silver and tin printed-circuit-board surface finishes in lead-free solder applications

2004 ◽  
Vol 33 (9) ◽  
pp. 977-990 ◽  
Author(s):  
Minna Arra ◽  
Dongkai Shangguan ◽  
Dongji Xie ◽  
Janne Sundelin ◽  
Toivo Lepistö ◽  
...  
Keyword(s):  
Printed Circuit Board ◽  
Circuit Board ◽  
Lead Free ◽  
Lead Free Solder ◽  
Printed Circuit ◽  
Surface Finishes ◽  
Board Surface ◽  
Free Solder ◽  
Immersion Silver

IMC Growth Mechanisms of SAC305 Lead-Free Solder on Different Surface Finishes and Their Effects on Solder Joint Reliability of FCBGA Packages

2009 ◽  
Vol 6 (2) ◽  
pp. 119-124 ◽  
Author(s):  
Sang Ha Kim ◽  
Hiroshi Tabuchi ◽  
Chika Kakegawa ◽  
Han Park
Keyword(s):  
Solder Joint ◽  
Isothermal Aging ◽  
Lead Free ◽  
Lead Free Solder ◽  
Solder Joint Reliability ◽  
Joint Reliability ◽  
Surface Finishes ◽  
Cu3sn Layer ◽  
Cu6sn5 Layer ◽  
Free Solder

Intermetallic compound (IMC) growth behavior of lead-free solder plays an important role in ball grid array (BGA) solder joint reliability for flip chip BGA (FCBGA) packaging applications. The growth mechanism of IMC is reported based on a diffusion model. Thermal treatment such as accelerated thermal cycling (ATC) and isothermal aging exposure also contribute to the growth rate and morphology of lead-free solder IMC. Among the lead-free solder alloys, Sn-3.0wt.%Ag-0.5wt.%Cu (SAC305) solder is a promising substitute for Sn-Pb because of its good mechanical properties and wettability with current surface finishes. After thermal exposure, BGA solder joint reliability is degraded due to IMC formation and growth. In this study, two different thermal treatments, ATC and isothermal aging, and two different pad surface finishes, solder on pad (SOP) and electroless Ni immersion gold (ENIG), are considered in terms of IMC growth rate and mechanical solder joint reliability. An SOP finished interface forms a thin ε-phase Cu3Sn layer and a scallop-like η-phase Cu6Sn5 layer. In contrast, the ENIG finished interface forms a thick (Cu,Ni)6Sn5 IMC layer and prevents overall IMC growth. Different surface finished test vehicles are evaluated in an ATC test in a 0°C to 100°C temperature range and the Ni diffusion layer shows a longer solder joint fatigue lifetime than the nondiffusion barrier interface based on the micro cross-section and dye penetration analysis results. In an isothermal aging test at 100°C and 150°C, the aging temperature and time are valid factors to decide mechanical shock reliability. Interfacial fractures are found in the 100°C aged test vehicle due to easier crack propagation at the interface between the thin Cu3Sn layer and the scallop-like Cu6Sn5 layer based on SEM microstructure analysis results. Finally, this investigation proposes how to improve solder joint reliability and prevent interfacial fracture for SAC305 lead-free application.

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