Dr. Jennie Hwang will deliver two Courses at SMTA International Exhibition & Conference on October 15, 2012, Orlando, Florida

Manufacturing PCB assemblies containing grid array packages in the co-existence of RoHS lead-free compliant and RoHS exempted industry sectors poses great challenges to both OEMs and EMSs. Much confusion has been generated. This course aims to clear the confusion and offer answers to industry-wide questions on solder-ball-array packages and assembly (BGA, CSP, WLP, and LGA) in manufacturing, as well as reliability. Questions to be answered include "Should reflow peak temperature be set to melt BGA solder balls?"

and

"What is the best practice for assembling lead-free components under the SnPb process?" The course provides working knowledge with focus on the challenges and solutions for Ball Grid Array (BGA) packages, fine pitch BGA and other BTC packages containing solder balls as interconnection technology. Using solder paste, six commonly occurring scenarios covering the backward and forward compatibility (backward compatibility: lead-free BGA using tin-lead solder paste; forward compatibility: lead-free BGA with lead-free solder paste) will be specified including the PCB assembly containing both lead-free BGA and tin-lead BGA. The desirable reflow process parameters will be specified. Real world production process parameters critical to the reliability and the impact of key process parameters will be presented. The course also discusses what constitutes the best practices enabling the manufacture of the ultimate reliability of PCB assemblies and the scientific rationale behind such practices.

The presentation will be concluded with the summary of relative ranking of the product reliability (solder joint reliability plus the PCB assembly integrity). Specific topics to be covered:
•         Array package (BGA, CSP, WLP, BTC) interconnection – challenges; Array solder interconnection technology – principles, best practices
•         Should the reflow profile set to specifically melt BGA solder balls?
•         Key process parameters for commonly occurring production scenarios and rationale
•         PCB assembly: BGA with SAC305 solder ball using SnPb(E) solder paste
•         PCB assembly: BGA with SnPb(E) solder ball using SAC305 solder paste
•         PCB assembly: BGA with SAC305 solder ball using SAC305msolder paste
•         PCB assembly: BGA with low-Ag SAC solder ball using SAC305 solder paste
•         PCB assembly: BGAs with SAC305 solder ball using low-Ag SAC solder paste
•         PCB assembly: BGAs with low-Ag SAC solder ball using low-Ag SAC solder paste
•         Solder joint reliability and PCB assembly integrity – principles, processes, failure prevention
•         "What constitutes the best practices that enable the ultimate reliability of PCB assemblies and the scientific rationale behind?"

T16: Preventing Production Defects and Failures

Introduction
Considering the new and anticipated developments in packaging and assembly, this course focuses on "how-to" prevent the issues and take remedial measures of the prevailing production defects through the understanding of potential causes. Top five current issues/defects addressed in this half-day course include PCB bare board issues, PCB Pad cratering, BGA head-on-Pillow defect, passive 01005 issues, copper dissolution and Pb-free thru-hole barrel filling problem. PCB thermal properties and halogen-free PCB laminates will be summarized. New developments in tin whisker and mitigating measures will also be outlined. Attendees are encouraged to bring their issues for discussion. Specific topics to be covered:
•         PCB – thermal properties for Pb-free assembly
•         PCB – Halogen-free laminates
•         PCB Pad cratering – causes, solutions
•         Head-on-pillow defect – causes, factors, remedies
•         Copper dissolution – impact on thru-hole solder joint reliability
•         Through-hole barrel filling – process, solder joint integrity
•         Tin whisker – new developments
•         Passive 01005 assembly – process, factors, best practice
•         Your issues

For info/registration:  https://www.smta.org/event_registration/smtai_register.cfm

TIN/TIN ALLOY NANOPARTICLE HAVING LOW MELTING TEMPERATURE AND METHOD FOR MANUFACTURING SAME

Disclosed are a nanoparticle having a size of 1-20nm prepared by electrolyzing a tin or a tin alloy, and a method for preparing same. The nanoparticle surface-melts in a temperature range of 80-130?. A solder ball having the nanoparticle can be sintered at or below 160?, and can thus, first, save 22% of energy by resolving the energy consumption of 74 kW for the conventionally used reflow processing device to an energy consumption of 50 kW by enabling the heating temperature to be lowered from 240? to 160? during reflow process. Second, deformation of a PCB board can be minimized by enabling the temperature for the reflow process to be lowered, and application areas for implementation materials having a low unit cost can be created by enabling the use of low cost polymer materials such as PET having low glass transition temperature. And third, the uniformity of a solder paste on a pad can be enhance when using a nanoparticle having a size of 10 nm or smaller, and in the case of a nano-solder ink, the limitations of micro-patterning can be overcome due to the small size of the particle (Figure 4).



WO2012096489  (A2)  -  TIN/TIN ALLOY NANOPARTICLE HAVING LOW MELTING TEMPERATURE AND METHOD FOR MANUFACTURING SAME
Inventor(s): KIM YOUNG SANG [KR] +
Applicant(s): ISP CO LTD [KR]; KIM YOUNG SANG [KR]; CHO KYUNG JIN [KR]; JANG SEOK PIL [KR]; LEE JONG HYUN [KR]; KIM HYUN SOO [KR] +
Classification:
- international: B22F1/00; B23K35/26; C25C5/02
- European:
Application number: WO2012KR00223 20120110 
Priority number(s): KR20110002482 20110110

Proportional hazards model for reliability analysis of solder joints under various drop-impact and vibration conditions

A new study on Mechanical Engineering is now available. According to news reporting out of Shanghai, People's Republic of China, by VerticalNews editors, researchers stated "This paper is devoted to the use of a proportional hazards model (PHM) for reliability analysis of solder joints through two case studies: a drop-impact test and a vibration test. The lifetime data collected under various load conditions can be integrated in establishing a PHM for reliability analysis of solder joints."

Our news journalists obtained a quote from the research by the authors from Shanghai Jiao-Tong University, "PHM has the capability of evaluating the influence of load conditions (e. g. drop height, power spectrum density in random vibration) on the life span of solder joints. Using this capability, this paper focuses on the implementation of PHM for estimating the reliability characteristics (MTTF and probability density function (p.d.f.) of failure) of solder joints whose load conditions are not contained in the training dataset of the PHM. In comparison with the naive use of lifetime data by simply ignoring the effect of load conditions, the two case studies verify the effectiveness of PHM in providing consistent reasonable estimation of the reliability characteristics of solder joints."

According to the news editors, the researchers concluded: "The perspectives and the procedures of the use of PHM in this paper are generic and can be directly adopted for other systems/products."

For more information on this research see: Proportional hazards model for reliability analysis of solder joints under various drop-impact and vibration conditions. Proceedings of the Institution of Mechanical Engineers Part O-Journal of Risk and Reliability, 2012;226(O2):194-202. Proceedings of the Institution of Mechanical Engineers Part O-Journal of Risk and Reliability can be contacted at: Sage Publications Ltd, 1 Olivers Yard, 55 City Road, London EC1Y 1SP, England.

Hydrochloric Acid; Investigators at INSTM Detail Research in Hydrochloric Acid

2012 JUL 25 (VerticalNews) -- By a News Reporter-Staff News Editor at Electronics Newsweekly -- Investigators publish new report on Hydrochloric Acid. According to news reporting originating from Genoa, Italy, by VerticalNews correspondents, researchers stated "The corrosion behaviour of the Sn94.5Ag3.8Cu1.5 (SAC) eutectic alloy was investigated in 0.1M NaCl solution by potentiodynamic polarization and impedance spectroscopy measurements and compared with that of the conventional Sn73.9Pb23.1 eutectic solder employed for a long time in the packaging of microelectronic components and devices. Scanning electron microscopy (SEM) and electron probe microanalysis (EPMA) were used to characterize the SAC eutectic alloy prior to and after the electrochemical tests."

Our news editors obtained a quote from the research by the authors from INSTM, "The electrochemical results indicated that the SnAgCu eutectic alloy exhibits better corrosion behaviour than the SnPb eutectic solder in NaCl solution. The presence of a corrosion products layer constituted by tin oxy-chloride was detected at the surface of both alloys investigated after the electrochemical tests."

According to the news editors, the researchers concluded: "The better corrosion behaviour of SAC eutectic alloy compared to SnPb eutectic solder is ascribed to the formation of a more compact surface film of corrosion products with improved protective properties owing to the presence of copper and silver, as revealed by EPMA."

For more information on this research see: Electrochemical corrosion behaviour of Sn-Ag-Cu (SAC) eutectic alloy in a chloride containing environment. Materials and Corrosion-Werkstoffe Und Korrosion, 2012;63(6):492-496. Materials and Corrosion-Werkstoffe Und Korrosion can be contacted at: Wiley-V C H Verlag Gmbh, Boschstrasse 12, D-69469 Weinheim, Germany.

The news editors report that additional information may be obtained by contacting F. Rosalbino, Natl Consortium Mat Sci & Technol INSTM, Genoa Res Unit, Genoa, Italy.


Electronics Newsweekly

ELECWK

964

English

© Copyright 2012 Electronics Newsweekly via VerticalNews.com

LOW SILVER SOLDER ALLOY AND SOLDER PASTE COMPOSITION

A low silver solder alloy of the present invention comprises 0.05-2.0% by mass of silver; 1.0% by mass or less of copper; 3.0% by mass or less of antimony; 2.0% by mass or less of bismuth; 4.0% by mass or less of indium; 0.2% by mass or less of nickel; 0.1% by mass or less of germanium; 0.5% by mass or less of cobalt (provided that none of the copper, the antimony, the bismuth, the indium, the nickel, the germanium, and the cobalt is 0% by mass); and the residue is tin. According to the present invention, the long-term reliable low silver solder alloy is provided, wherein the low silver solder alloy permits the cost reduction by decreasing the Ag content, and has the excellent stretch, melting point, and strength, and also has the high fatigue resistance (thermal fatigue resistance).

Page bookmark	US2012175020  (A1)  -  LOW SILVER SOLDER ALLOY AND SOLDER PASTE COMPOSITION
Inventor(s):	IMAMURA YOJI [JP]; IKEDA KAZUKI [JP]; PIAO JIN YU [JP]; TAKEMOTO TADASHI [JP] +
Applicant(s):	HARIMA CHEMICALS INC [JP] +
Classification:	- international: B23K35/24; C22C13/02 - European:
Application number:	US201113376563 20110512
Priority number(s):	JP20100242916 20101029; WO2011JP60983 20110512
Also published as:	EP2468450  (A1)   JP4787384  (B1)   WO2012056753  (A1)   CN102574251  (A)

5 Key Success Factors for Medical Electronics PCBs

It comes as no big surprise that the market demand for smaller, more compact, handheld medical electronics products is dramatically escalating. The burden is on both the OEM and its contract manufacturer (CM) or EMS Provider to work in close cooperation to expertly deliver the five success factors for medical electronics PCBs. Plus, stringent compliance with ISO 13485:2003 assures the OEM critical requirements are met. This paper gives you the necessary insight into those five success factors and the critical PCB areas the medical electronics Standard covers.

5 Key Success Factors for Medical Electronics PCBs: