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.

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.

Enabling Cu Pillar Flip Chip Assembly with Water Soluble Lead-free Solder Paste

2019 ◽  
Author(s):  
B. Senthil Kumar ◽  
Bayaras Abito Danila ◽  
Chong Mei Hoe Joanne ◽  
Zhang Rui Fen ◽  
Santosh Kumar Rath ◽  
...  
Keyword(s):  
Flip Chip ◽  
Water Soluble ◽  
Lead Free ◽  
Lead Free Solder ◽  
Solder Paste ◽  
Cu Pillar ◽  
Flip Chip Assembly ◽  
Free Solder

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.

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.

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