Richard has worked in the electronics industry for more than 35 years primarily working in the development and implementation of solder materials and related chemistries on customer production lines.
Electrically Conductive Adhesives v Solder: Which solution?
Electrically Conductive Adhesives v Solder: Which solution? Reviewing the pro’s and con’s of solutions best suited for your application Electrically conductive adhesives and low melting alloy solders are not new but which is the best sustainable option for your products. This paper will look at the benefits and negatives for each chemistry (epoxies, silicones, acrylics, bis-maleimides) and looks at how this will impact your production process and the reliability of the product you produce. We will take you through the physical properties of each application and process steps needed for each to work and what can happen after it is produced. This could help you avoid some of the pitfalls you may encounter along the way in deciding which solution to use.
Advanced Technology Manager at ITWEAE. Responsible for soldering processes and new technology developments with over 30 years experience. Published over 50 technical papers and is an IPC-A-610 certified trainer.
Challenges of a low temperature solder in selective soldering process
Low temperature solders are becoming popular in surface mount technology. Lower melting alloys not only benefitted a reflow soldering process but may also be used in through hole technology. Selective soldering requires higher solder temperatures to get a good hole filling with small nozzles. There is a potential risk for fillet or pad lifting, melting of plastics, or even deactivation of flux systems when operation temperatures are high. This is a feasibility study of selective soldering using low temperature solders. In this project a SnBi based alloy with a large melting range is used for soldering THT components.
Mike has over 30 years experience in the electronics industry and specializes in the measurement and control of machine soldering processes.
Measuring and Controlling Machine Based Soldering Processes: The Impact of LTS
This presentation will concentrate on the impact that LTS has on the physical act of thermal profiling of reflow, wave and selective soldering processes. It will address the subtle differences that LTS introduces when compared to more conventional temperatures and suggest alternative methods of process control that can be adopted to ensure a “best practice” approach to ongoing measurements and reporting.
Dr. Ian Tevis is a Materials Chemist and has been the CTO and President of SAFI-Tech for 5 years. He is the inventor of four patented technologies and the inventor of using supercooled liquid metal microcapsules as interconnect materials.
Lower Temperature Soldering Without Changing Solder Alloy Composition Using Supercooled Liquid Metal
Lead-free solder metal alloys can be used to create full metal interconnects at dramatically lower processing temperatures with or without bismuth by using the new form factor of supercooled liquid metal microcapsules. The technology encapsulates known and established RoHS compliant solder alloys inside a nanofilm that keeps the metal in a metastable supercooled liquid state at ambient temperatures. The novel solder interconnect technology invented by SAFI-Tech avoids thermal damage to components and materials, or quality issues caused by coefficient of thermal expansion mismatch.
MacDermid Alpha Electronics Solutions
Alan Plant is a Regional Technical Manager – Europe for MacDermid Alpha Electronics Solutions. He has 38 years experience in the electronics industry both in manufacturing and materials supply. He has a degree in Metallurgy.
Using LTS for Soldering Through Hole Components
Feasibility of low temperature selective and wave soldering processes was evaluated. Soldering performance of newly developed Si-Bi based alloy having liquidus <150 °C was tested in both wave and selective soldering processes using organic acid based liquid fluxes. Multiple alloy performance attributes, including hole fill on 2.4 mm multi-layer PCBs, were evaluated. Additionally, testing and identification of multiple, currently available, flux chemistries was performed to ensure electrochemical reliability is maintained using lower processing temperatures. This paper covers testing results, conclusions and recommendations derived from the study.
Koki Solder America
Bio Jasbir Bath is a Support Advisory Engineer for Koki Solder America, Inc. He was a Corporate Lead Engineer with Solectron Corporation/Flex and a Technical Officer at ITRI (International Tin Research Institute/ Tin Technology) Ltd. in the U.K. He has been involved with the INEMI Board Assembly Roadmap for over 10 years. He holds BS and MS degrees in Materials Science from the University of Manchester/ UMIST in England, U.K. Jasbir is the editor of the Wiley book: Lead-free Soldering Process Development and Reliability and Springer Publications book: Lead-free Soldering. He is co-editor of 3 IEEE-Wiley books: Lead-free Electronics – iNEMI Projects Lead to Successful Manufacturing, Lead-free Solder Process Development and Mitigating Tin Whisker Risks – Theory and Practice. He has also co-authored the Lead-free Manufacturing chapter of the IEEE-Wiley book: Lead-free Electronics.
Development of Low-Melting Point Lead-free SnBiAg Solder Paste with Improved Surface Insulation Resistance Reliability at Low Reflow Soldering Temperatures.
There has been a persistent demand for lead-free low-melting temperature solder paste for some time from the viewpoint of power consumption reduction and electrical reliability of an assembly as a whole. Several Sn-Bi based alloy products are available in the market. Conventional Sn-Bi solder pastes often contain large amounts of relatively strong activator to secure meltability and coagulation equivalent to that of Sn3Ag0.5Cu no-clean paste. However, if the solder paste is not sufficiently heated during low-temperature reflow, a part of the solvent could remain in the flux residue and soften it, thus becoming an insulation resistance reliability concern. Even if the solder paste is designed so that the solvent will evaporate easily for better insulation resistance, there is a trade-off as the solder paste may dry up too quickly, negatively affecting the paste printing, viscosity, and tackiness properties. A low temperature Sn0.4Ag57.6Bi no-clean solder paste was developed with a carefully selected flux activator that effectively starts to facilitate the reduction-oxidation reaction even during the pre-heat stage where the solder particles in the paste are still unmolten, thereby minimizing the amount of the added flux activator needed while securing excellent meltability, wettability and coagulation, as well as high insulation resistance of the flux residue. As well as improving the insulation resistance, it helps to achieve stability in continual printing applications and in holding and securing components in place during and after the component placement process. The resultant reflowed solder joints also have low voiding. Evaluations on the developed solder paste included intermittent and continuous paste printing, tack time, component tackiness, paste viscosity change over time during storage, reflow behavior on soldered chip components, voiding evaluations on BTC/QFN, power transistor and 6330R chip components and insulation resistance reliability with different reflow profiles with results reported.
PSU, Portland, OR, USA
Ephraim Suhir is on the faculty of the Portland State University, Portland, OR, USA, Technical University, Vienna, Austria and James Cook University, Queensland, Australia. He is also CEO of a Small Business Innovative Research (SBIR) ERS Co. in Los Altos, CA, USA, is Life Fellow of the IEEE, the ASME, the SPIE, and the IMAPS; Fellow of the APS, the IoP, UK, and the SPE; and Associate Fellow of the AIAA. Ephraim has authored 450+ publications, presented numerous keynote and invited talks worldwide, and received many professional awards, including 1996 Bell Labs DMTS Award, 2004 ASME Worcester Read Warner Medal (for laying the foundation of a new discipline “Structural Analysis of Electronic Systems”). His most recent awards are 2019 IEEE EPS Field award and 2019 IMAPS Lifetime Achievement.
Inhomogeneous bonding in low-temperature-soldering technologies
Significant stress relief in solder joints can be achieved not only by using low soldering temperatures, but also by employing inhomogeneous bonds, when, e.g., a high-melting-point and/or a high modulus solder is employed in the mid-portion of the assembly and a low-melting-point solder and/or a solder with a lower modulus, or even an epoxy, is employed at its peripheral portions. The incentive for the application of inhomogeneously soldered assemblies is due also to the attractive opportunity to use solders with high thermal conductivity in the assembly’s mid-portion, and employ stronger solders at the assembly’s relatively short peripheral portions. It has been shown particularly (E.Suhir, Avoiding Inelastic Strain in Solder Material of IC Devices, CRC Press, 2020) that significant stress reduction, of about 35%, can be achieved, if one requires that the interfacial shearing stresses at the ends of an inhomogeneously bonded assembly are equal to the stresses at the boundaries between the assembly’s long mid-portion, where high-modulus and/or high-melting-temperature solder is applied, and its short peripheral portions, where a low-modulus and/or a low-melting solder (or even an epoxy) is used. Such maxima could be even below the yield stress of the solder material. If this happens, the low-cycle fatigue condition will be avoided. Future work should be focused mostly on experimental investigations aimed on proving these findings.
Heraeus Materials Singapore Pte Ltd
Evonne Lim is currently a R&D Engineer working in Heraeus Singapore, where she is actively involved in bonding wire, sinter & solder material characteristic related research & paper publication. She received her Bachelor of Material Engineering degree from Sheffield Hallam University, UK in 2010. She has about 10years experience of electronic interconnect material, process & electroplating in semiconductor industry.
A Study on Interfacial Intermetallic Phases at Sn-Bi Solder Joint
The present study enumerates the morphology/type of intermetallic phases that form at the interface of Sn-Bi alloy when soldered to different plated surfaces Au, Ag, Cu, Sn, Pd. Bismuth doesn’t form any intermetallic phases, while Sn in the alloy would readily form Sn based intermetallic phases. Thus, in Sn-Bi alloy with high fraction of Bi content (40 to 58%) also lead to formation of Sn based intermetallic compounds at the interface, in the form of scallops/flakes/layers (single or multiple) for a thickness in the range from 0.2µm to 8µm. Crack initiation and propagation during thermal cycling and mechanical drop tests get influenced by these interface intermetallic layers. In addition, electrical resistivity, shear strength, corrosion resistance (lab based test), rate of growth of intermetallic phases on thermal ageing of the Sn-Bi solder joints are to be addressed.
Interflux Electronics NV
Steven Teliszewski has 24+ years of experience in analyzing and solving problems in a wide variety of soldering applications and processes. This expertise is being shared on a regular basis for many years now on technical seminars and fora worldwide.
Practical experiences with a low melting point alloy in wave and selective soldering
The benefit in using a low melting point alloy obviously is situated in the potential to reduce working temperatures in the soldering processes. The thermal stress is reduced and hence also the risk on high temperature related defects and predamaged components. For wave and selective soldering some extra benefits can be obtained compared to Sn(Ag)Cu alloys, like easy through hole wetting on thermally heavy electronic units and also significantly faster soldering speeds. This presentation provides insight in these benefits by means of some practical examples from the field where a low melting point alloy was used for that purpose.
Claire Hotvedt is responsible for facilitating the transition of new solder paste products from developmental stages into fully launched solutions. She oversees product characterization and works closely with the RnD and sales teams.
Reducing Reflow Temperature and Retaining Material Properties with Mixed Powder Solder Technology
Low temperature solders (LTS) with reflow peak temperatures of 200℃ or below are valuable SMT process tools. However high indium and high bismuth containing materials have drawbacks in regards to temperature sensitivity and mechanical shock reliability. Novel mixed powder solder technology allows us to bring mid-temperature solder properties into the upper edge of the low-temperature space. Taking advantage of mixed-powder solder opportunities also requires a new understanding of the reflow process considerations using a plateau type profile.
SEHO Systems GmbH
Dr.-Ing. Andreas Reinhardt is director R&D and member of the management board at SEHO since 2014. After his studies in mechatronics he worked at the institute FAPS from 2006 to 2013, being responsible for the research group ‘electronics production’ since 2011.
BSA solder for wave soldering – requirements and energetic effect
Soldering processes represent a very important part of the energy consumption in the production of electronics. In this article, the essential consumers within soldering systems are explained. In order to achieve significant savings, wave soldering with low-melting solder (BSA) is presented in detail and the requirements for the product and system technology are discussed. The basis for this is a process comparison of BSA with Lot SN100C using test assemblies. The evaluation is carried out in relation to product quality (hole fill, component temperatures) and the savings potential in resource consumption.
Vinzenz has over 20 years experience as a material scientist Diploma in Materials Engineering / Master of Science ETH in Material Science Expert in surfaces and interfaces, process optimization, furnace construction, and general metallurgy/metallography as well as associated analysis methods.
Challenges in jetting and dispensing of low-temperature solder paste
Low-temperature solder paste is more and more widely used in industry so also jetting and dispensing of these solder paste are in the focus of development at Essemtec. The impact of the different metallurgical and chemical properties of the low-temperature solder paste on the jetting and dispensing process is shown. One example is that lower soaking and soldering temperature will lead to a different composition of solder paste with more volatile Ingredients. One result can be faster drying of the solder paste and a faster reduction of tackiness.
Hans-Jürgen began his career in 1989 at Philips Semiconductors as an engineer for the electrical characterization of transistors and diodes. He then moved into package development, focused on discrete semiconductors and specifically magnetic field sensors (ABS and angle) where he introduced several different package options. Since 2006 he has worked in the package competence group, addressing package roadmaps and working on recommendations for surface mount (SMT) assembly of semiconductor packages…
Low Temperature Soldering Application Study
Several components representing a wide range of external lead finish (plating) of semiconductor packages will be assembled on PCB using commercially available SnBiX solder known as low temperature solder (LTS) and standard SAC solder. The used components are leaded, leadless and chip scale packages (CSP) with flat pads and WLCSP with solder balls. Automatic solder printing and thermal profiling will be adapted and analyzed. Component tilting for 2 I/O devices, solder IMC phase formation as well as electrical and mechanical testing on board level will be done in comparison to SAC soldered components. Further investigations including temperature cycling and drop testing will be reported at a later point.
Vahid has over 14 years of experience in the Printed Electronics field, over 20 peer reviewed publications, several patent applications and has presented at numerous technical seminars and workshops. His current research interests involve printing functional electronic devices on inexpensive flexible substrates.
Circumventing the Thermal Challenges with Reflow Using High Powered Flash Lamps
High powered flash lamps are used to reflow solder in a nonequilibrium processing step, leading to wide range of substrate, materials and component selection. This technique enables the use of temperature sensitive substrates with conventional higher temperature solder alloys. This presentation introduces the novel soldering technique, discuss the advantages, provides an overview of the resulting solder joints and discusses the application space for this technology.