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Solutions SnPb Soldering: Are you exempt from the recent transition to lead free soldering? That doesn’t mean all your problems went away. More... Lead Free Soldering: Many have done it for years, but surprises abound. It is time to break completely with common, empirical expectations. More... Backward Compatibility: Components with lead free solder balls can still be soldered with eutectic SnPb paste, and often it seems to work. However, don’t do it unless you have to! More... Solder Pad Finishes: Lead free soldering tends to exacerbate familiar solder pad finish issues, as well as leading to ‘new’ ones. More... Printed Circuit Boards: Most damage caused in lead free assembly is not immediately obvious and is rarely tested for. More... PCB Design & Materials: Materials selection, design and tolerances may strongly affect assembly yields and the risk of damage. More... Testing of PCB structures and materials: Common tests only address a few of our major concerns, and some of them are inappropriate for lead free applications. More... Flip Chip: Eutectic SnPb solder assembly is well established, albeit often poorly understood. Switching to lead free soldering poses additional challenges. More... Reliability Testing: Common test protocols are far from always based on a mechanistic understanding, and it gets worse for lead free soldering. Thermal cycling of lead free soldering poses particular problems. More... Mechanical Testing: Mechanical testing is in principle easier to understand, but competing and interacting failure modes tend to complicate interpretation and generalization of results. More... Mobile Applications: The phenomena of concern are very different for cell phones, aerospace, medical implants, external defibrillators, and so on. Synergistic effects are often particularly critical, but not trivial to address. More... Failure Analysis: Failure may occur during assembly, handling, ICT, transport, storage and service, perhaps due to cumulative damage during several of these. Analysis and interpretation requires appropriately adapted practices and an in-depth understanding of the, often competing and interacting, mechanisms. More... Assembly: Assembly is rarely a problem, unless you care about cost or reliability. Ensuring high yields in high speed assembly with the least expensive materials, components and equipment without damaging anything may however drastically narrow your windows and require a lot of optimization, particularly with lead free solders. More... Design For Assembly: Optimizing assembly includes designing to minimize defects in placement or reflow. We have developed a series of specific design and process guidelines, as well as software for use in ‘what if’ studies to optimize designs. More... Stencil Printing: Solder paste printing is a well established assembly tool. Printing of underfills, thermal interface materials, die attach, etc. sometimes offers advantages over dispensing in terms of throughput and defect reduction. Design and process optimization based on a mechanistic understanding of particle-matrix ‘filtration’ and the flow into and out of apertures allows for higher yields and extension to finer pitches and dimensions. More... 0201 Assembly: Tombstoning, bridging, and solder balling defects depend on attachment pad and stencil design, solder paste selection, printing and component placement accuracy, and reflow. This may, however, be one of the few cases where the transition to lead free soldering makes things easier. More... Thermal Interface Assembly: Heat dissipation depends on materials properties, realistically maintainable bond line thickness, and process induced defects. Often, thermal interface materials with superior ‘bulk’ properties offer a clearly inferior performance and/or reliability in actual products. More... Conductive Adhesive Assembly & Reliability: Electrically and/or thermally conductive adhesives are sometimes used in applications with strict process limitations. Adhesives replacing solder joints are subject to very different reliability concerns. More... Repair: The balance of solder joint quality against the risk of damage to PCB or component limits the process windows, especially for lead free solders. Our process guides are based on extensive testing for hidden damage and reliability, while minimizing demands on operator skills. More... Component Underfilling: BGAs and CSPs are often underfilled to enhance robustness under mechanical loads, but there is also a growing need for underfilling to enhance, or at least not reduce, thermal cycling resistance. Often, the issues and trade-offs are much more complex than for conventional flip chip underfilling, especially with lead free solder. More... Die Cracking: Silicon is an extremely strong material. Die cracking under mechanical loading or thermal excursions is invariably associated with defects, and thus sensitive to back lapping and dicing procedures. Also critical are details of how the die is attached, and to what, as well as die thickness. More...
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