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Lead-Free
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A Study of Lead-Free Wave Soldering
AIM Abstract: This brief study of lead-free wave soldering focuses upon copper dissolution and solder maintenance issues. Unfortunately, it is determined that waste and changeover costs can dramatically increase with lead-free wave soldering. 
A Comparison of Lead-Free AIM Abstract: Based on recent market developments, it appears that the choice of suitable lead-free alloys to replace Tin-Lead for electronics assembly is narrowing. Three candidates have emerged as potential standards for the industry. They are the Tin-Copper eutectic (Sn99.3/Cu0.7), the Tin-Silver eutectic (Sn96.5/Ag3.5), and CASTIN® (Sn96.2/Ag2.5/Cu0.8/Sb0.5). This paper details extensive testing covering several variables that was conducted in order to make objective comparisons between the three alloys.
A Comparison of Lead-Free AIM Abstract: Based on recent market developments, it appears that the choice of suitable lead-free alloys to replace Tin-Lead for electronics assembly is narrowing. Three candidates have emerged as potential standards for the industry. They are the Tin-Copper eutectic (Sn99.3/Cu0.7), the Tin-Silver eutectic (Sn96.5/Ag3.5), and CASTIN® (Sn96.2/Ag2.5/Cu0.8/Sb0.5). This paper details extensive testing covering several variables that was conducted in order to make objective comparisons between the three alloys.
Pb-Free Solder Joint Evaluation AIM Abstract: The goal of this study was to evaluate a totally Pb-free solder joint formed by using TI 4-layer Ni/Pd finish IC components, CASTIN Pb-free solder paste, and ENTEK® PLUS Organic Solderability Preservative (OSP) as the PWB surface finish. Mechanical tests performed included contact angle measurements and lead pull. Temperature cycle testing was performed to evaluate the package integrity after cycling through temperature extremes. The wetting balance test was used as a tool to determine the solder wetting time for the individual IC components.
A Study of Lead-Free Alloys AIM Abstract: With the ongoing concerns regarding environmental pollutants, lead at one time was heavily targeted in the electronics assembly arena. AIM reacted to these concerns by developing its patented lead-free alloy CASTIN®. This paper highlights the development process and application information for CASTIN®.
Lead-Free Wave Soldering Evaluation Update Circuits Assembly This article concentrates on one issue: the copper erosion of surface tracking on the printed board (PCB) in contact with the wave, when using lead-free solders. (added on 09-Feb-2003)
Materials and Process Considerations for Lead-Free Electronics Assembly AIM Abstract: With the WEEE Directive in Europe potentially outlawing lead from some electronic devices produced and imported in the EU by 2006 and foreign competition driving the implementation of lead-free electronics assembly around the world, additional questions regarding the integrity and reliability of various alloy compositions continue to arise. In short, the issue of which alloy(s) to select continues to loom. This paper shall take an in-depth view of Sn/Ag, Sn/Ag/Cu and Sn/Cu alloys and compare the reliability testing results and process considerations for these.
A Manufacturable Lead-Free Surface-Mount Process? Circuits Assembly NEMI demonstrates that lead-free manufacturing may be possible using existing production tools and equipment. (added on 03-Jan-2003)
Understanding Lead-Free Alloys AIM Abstract: One result of the push to find lead-free solder alternatives is that there are now many options available to the board assembler. Much development, patterning and research has gone into finding viable solutions for those who want to eliminate lead from their process. However, each of these alloys is different in significant ways and background information is necessary.
Are You Ready for Lead-Free Assembly? KIC
NEMI Report: A Single Lead-free Alloy Is Recommended SMT Magazine NEMI recommends a single lead-free alloy (Sn3.9/Ag0.6/Cu) to replace eutectic Sn/Pb solder for high-volume surface mount applications. This article explains why. (added on 26-Jan-2003)
No-Lead and Horizontal Hot Air Leveling AIM Abstract: A great deal of research has gone into the development of lead-free alloys for electronic soldering applications. However, less emphasis has been placed on finding viable lead-free alternatives for the hot air leveling (HAL) operation used during the fabrication of printed circuit boards. In order to investigate this and determine a possible alternative to tin-lead for the PC Fab operation, Teledyne Electronic Technologies, Halco (TET Halco), and AIM have collaborated on a hot air leveling evaluation of CASTIN®. All testing to date has shown CASTIN® capable as an alternative to the tin-lead alloys presently used during HAL.
Alloy Temperature Chart Kester Table with several types of alloys and their melting ranges
A Practical Guide to Achieving Lead-Free Electronics Assembly AIM Abstract: To successfully achieve lead-free electronics assembly, each participant in the manufacturing process, from purchasing to engineering to maintenance to Quality/Inspection, must have a solid understanding of the changes required of them. This pertains to considerations regarding design, components, PWBs, solder alloys, fluxes, printing, reflow, wave soldering, rework, cleaning, equipment wear & tear and inspection.
Reworking Lead-free Solder in PCB Assembly SMT Magazine While lead-free solder rework is more difficult because of the lack of wetting and wickability, successful rework and assembly methods have been developed with lead-free solders for all types of components. (added on 24-Jun-2003)
Lead-Free Hands On Experience Circuits Assembly Short description of the lead-free challenges, with nice photo's of some of the defects that may occur. (added on 06-Jul-2003)
VOC-Free Liquid Flux Development Circuits Assembly How to achive minimum defects with VOC free fluxes when used for lead-free wave soldering. (added on 15-Jun-2003)
Leadfree.org IPC hosts the Get the Lead Out! Web site
A Study of Antimony AIM Abstract: The issue of the toxicity of antimony has arisen as the search for viable lead-free alloys continues. Confusion regarding the toxicity of antimony has developed as a result of legislation concerning antimony trioxide, as well as unfounded speculation concerning the element in an alloyed form. This paper details third party and governmental studies and legislation concerning antimony and its ''toxicity''. This data then is compared to that of the ''safe'' elements that comprise the majority of lead-free solders, including silver, copper, zinc, compounds of tin, as well as lead. This data indicates that antimony is no more ''toxic'', often is far less-stringently regulated, and is classified as less of a health threat than many of the other aforementioned elements.
Texas Instruments Lead-Free Solutions Texas Instruments Lots of information about leadfree soldering, with a special focus on TI's Nickel/Palladium finishes. (added on 03-Jul-2003)
Lead-Contamination in Lead-Free Electronics Assembly AIM Abstract: The question of what happens to a lead-free solder joint if it becomes contaminated with lead is important because during the transition to lead-free soldering it is very likely that tin/lead parts will still be used in a great deal of production. In other words, just because one implements a lead-free solder alloy does not mean that tin/lead coated components and boards will disappear immediately. In fact, exposure to lead from boards, components and repair operations could occur for years to come. This paper discusses the dynamics of lead contamination and provides real-world examples of failures caused by the lead contamination of lead-free solders.
Speeding Up the Conversion Period for Lead-Free Products Electronic Packaging & Production Description of the many important aspects that must be adressed when making the conversion to a lead-free manufacturing. (added on 27-May-2003)
Industry Experts voice differing opinions on Lead vs. Lead-free Electronics SMT Magazine An interesting view on the trend towards Lead-Free production (added on 26-Jan-2003)
ITRI/NPL DTI report on lead-free soldering After filling in a form you can download the ITRI/NPL DTI report on the current status of Pb-Free soldering
EU Directive 2002/95/EC on the Restriction of the use of certain Hazardous Substances in electrical and electronic equipment Final Version of the EC-directive that forbids the use of lead and certain brominated flame retardants in electronic equipment starting 1 July 2006 (added on 22-Apr-2003)
Implementing Lead Free Soldering – European Consortium Research Loctite This paper describes the essential findings from a major collaborative programme of work carried out in Europe with funding from the European Community via the BRITE EURAM programme.
Integrity of Solder Joints from Lead-free Solder Paste Heraeus Circuit Materials Description of several lead-free alloys, and results of creep deformation testing for some of these materials. (added on 18-Oct-2003)
Specialty Solders: A Study of Indium/Lead AIM Abstract: More complicated electronics will require the increased use of specialty solders. Specialty solders, such as indium alloys, offer advantages for gold soldering, step soldering and fatigue resistance.
Overview Report on a Lead Free Electronics Industry Cemco Comprehensive report by Cemco providing backgrounds on the leadfree trend, with a focus on leadfree HASL. (added on 09-Nov-2003)
A Need for Change Cicuits Assembly Article adressing the temperature requirements of processing lead-free solder alloys and the termination finishes used as alternatives to tin/lead. (added on 04-Oct-2003)
Managing Lead-Free Compatibility Circuits Assembly Article that discusses the many compatibility issues that should be considered for a smooth transition to lead-free soldering. (added on 16-Nov-2003)
NEMI Recommends Standard Test Methods to Assess Propensity for Tin Whisker Growth SMT Magazine Standard test methods for tin whiskers will help the industry move more quickly in evaluation and development of Sn-based Pb-free finishes. (added on 28-Nov-2003)
N2 Inerting for Reflow of Lead-free Solders Advanced Packaging Article about the effects of nitrogen on reflow soldering results in lead-free assembly. (added on 15-Nov-2003)
Thermal Performance of Lead-free Packages Advanced Packaging This article compares air-to-air thermal cyclic reliability and associated failure modes of second level interconnects in lead-free 1.27-mm-pitch 256 I/O ball grid array (BGA) devices by examining three leading lead-free alloys and comparing their performance to that of ordinary tin-lead eutectic solder. (added on 01-Jan-2004)
A Benchmark Process For the Lead-Free A Benchmark Process For the Lead-Free Assembly of Mixed Technology Assembly of Mixed Technology PCB’s Alpha Metals The intent of this paper is to provide the industry with a practical, and technically feasible, lead-free process that can be implemented or used as a baseline to compare other more complex systems.
Global Trends in Lead-free Soldering, part 2 Advanced Packaging Part II of this lead-free series includes PCBs, SMT assembly processes, solder joint reliability, transition issues and substitutes. (added on 29-Feb-2004)
Lead-free soldering Electronic Production Electronics Production Magazine does not exist anymore, but their extremely usefull online-encyclopedia is still available from SMTinfo.net. This part gives an introduction to lead-free soldering..
Taking the Pain Out of Lead-Free Reflow Assembly Magazine Article about reflow profiling for lead-free assembly, advocating automated reflow management systems to achieve the required level of process control. (added on 16-Jan-2004)
Lead-free Implementation: No Need for Higher Temperature SMT Magazine Popular belief is that lead-free assembly means higher soldering temperatures. Dr. Jennie Hwang explains why this is incorrect. (added on 16-Jan-2004)
Global Trends in Lead-free Soldering Advanced Packaging Part 1 of a 2-part series on Lead-Free by John H. Lau, discussing regulations, soldering products and components. (added on 14-Feb-2004)
The Green Production Task Circuits Assembly Changing to “green” manufacturing is an imposing task and will require company teamwork across all involved departments. Article by Brian Sloth Bentzen of www.smtinfocus.com (added on 29-Feb-2004)
A Beginner’s Guide to Lead-Free Production Circuits Assembly A reviews of some of the practical issues involved with lead-free production. (added on 11-Apr-2004)
Step 3: Solder Materials SMT Magazine This article by Jennie S. Hwang focuses on the critical aspects of lead-free solder joint material, as well as production processes. (added on 11-Jan-2004)
Getting the Lead Out of Hot Air Soldering CircuiTree Magazine Article about leadfree alloys for Hot Air Solder Leveling (added on 03-Oct-2004)
Lead-free manufacturing Effects on press-fit connections Tyco Electronics This paper reports about concrete evaluations of different lead-free plated press-fit zones, in a combination with different lead-free board finishes. (added on 13-Jun-2004)
Lead-Free Soldering: DOE Study to understand its affect on Electronic Assembly Defluxing Leadfreemagazine.com The purpose of the study described in this paper was to evaluate how the use of nitrogen versus non-nitrogen reflow atmospheres affect the cleanability of flux residue from RMA, synthetic and water-soluble surface mount solder paste residues. (added on 13-Jun-2004)
Investigating Voids Circuits Assembly Investigations in the amount of voiding for various conductor finishes.It is concluded that the void profile of tin, silver and HASL is much smaller than for ENIG, possibly making these pad finishes more suitable for lead-free assembly. (added on 27-Jun-2004)
Lead-Free BGA Assembly Assembly Magazine Could a flip-chip ball-grid array (FCBGA) with 780 I/O be successfully assembled with lead-free solder at a peak reflow temperature below 260 C? How would lead-free solder affect joint reliability? How would it affect rework? A study was conducted to find out. (added on 07-Aug-2004)
The Next Generation of Solders for Electronics Chip Scale Review Overview of Leadfree Solder Alloys (added on 11-Sep-2004)
Lead-Free Hand Soldering of PTH Parts Circuits Assembly Bob Willis explains how to solder PTH parts with leadfree solder. (added on 11-Sep-2004)
What Can Go Wrong with Lead-free Soldering SMT Magazine Summary of things that can go wrong with leadfree soldering. (added on 11-Sep-2004)
Lead-free and Lead Contamination SMT Magazine Short article about lead contamination of leadfree solder. (added on 07-Nov-2004)
The Relationship between Reflow Soldering Processes and Power Consumption SMT Magazine Report about a study that focused on optimization of the reflow process to meet material specifications and still produce a quality solder interconnect. The study also characterized the power required to achieve the optimized process. (added on 07-Nov-2004)
Cause of Tin Whiskers Remains Elusive Advanced Packaging Although the rootcause of tin whiskers are still unknown, the knowledge about the phenomenon is growing. This article provides a short overview. (added on 11-Dec-2004)
Reliable Lead-free Wave and SMT Processes Advanced Packaging This article informs the reader about the many aspects to think of when implementing a lead-free wave soldering process. (added on 11-Dec-2004)
Assessing Solder Joint Reliability in Pb-Free Assemblies Circuits Assembly Research finds that bulk alloy properties are not a meaningful predictor of reliability. (added on 18-Dec-2004)
Transitioning to Lead-Free Assemblies Printed Circuit Design and Manufacture Convergence on a single lead-free alloy means studying compatibility (backward and forward), and materials and process development. (added on 06-Mar-2005)
01005s and Lead-Free Solder Assembly Magazine Tiny 01005s are challenging for any electronics assembly process, but they’re even more so if that process is lead-free. (added on 14-May-2006)
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© 2004 Daan Terstegge - All rights reserved. |