Papers about solder reliability
by Mario Scalzo
Chinese version of Addressing the Challenge of Head-in-Pillow Defects in Electronics Assembly.
CHINESE LANGUAGE, halogen-free, head-in-pillow, pb-free, solder defects, solder paste, solder reliability, lead-free
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Posted on 11 Mar 2010
by Mario Scalzo
White Paper Video
Addressing the Challenge of Head-in-Pillow Defects in Electronics Assembly
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The head-in-pillow defect has become a relatively common failure mode in the industry since the implementation of
Pb-free technologies, generating much concern. A head-in-pillow defect is the incomplete wetting of the entire solder joint of a ball-grid array (BGA), chip-scale package (CSP), or even a package- on-package (PoP), and is characterized as a process anomaly, where the solder paste and BGA ball both reflow but do not coalesce. When looking at a cross- section, it actually looks like a head has pressed into a soft pillow. There are two main sources of head-in-pillow defects: poor wetting and printed writing board (PWB) or package warpage. Poor wetting can result from a variety of sources, such as solder ball oxidation, an inappropriate thermal reflow profile or poor fluxing action. This paper addresses the three sources or contributing issues (supply, process and material) of the head-in-pillow defects. It will thoroughly review these three issues and how they relate to result in head-in-pillow defects. In addition, a head-in-pillow elimination plan will be presented with real life examples to illustrate these solutions.
lead-free, solder reliability, solder paste, solder defects, pb-free, head-in-pillow, halogen-free
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Posted on 11 May 2009
by Dr. Ronald C. Lasky
Miniaturised electronics and the advent of
lead-free soldering have added new challenges to the SMT electronic assembly process, most notably in the arenas of stencil printing and reflow. Recent work on improving these assembly processes and advances in solder paste technology can help to minimise these process challenges.
halogen-free, solder paste, solder, solder reliability, flux, pb-free, lead-free
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Posted on 15 Mar 2009
by Karl Pfluke , Richard H. Short
The advent of Lead-Free Soldering presents many manufacturers with the need to Wave Solder using
Lead-Free Alloys . These alloys melt and are soldered at temperatures well above conventional SNPB processing temperatures. This creates several well-documented problems. This article offers a proven and practical alternative to the Lead-Free Wave Soldering Process.
lead-free, wave solder flux, pb-free, Rework, solder preforms, solder paste, solder reliability
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Posted on 1 Jan 2009
by Karl Pfluke , Richard H. Short
German version of Eliminate Lead-free Wave Soldering.
lead-free, wave solder flux, German language, pb-free, Rework, solder preforms, solder paste, solder reliability
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Posted on 1 Jan 2009
by Chris Anglin
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Establishing a Precision Stencil Printing Process for Miniaturized Electronics Assembly
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The advent of miniaturized electronics for mobile phones and other portable devices has required the assembly of smaller and smaller components. Currently 01005 passives and 0.3mm CSPs are some of the components that must be assembled to enable these portable electronic devices. It is widely accepted that about 65% of all end of the line defects occur in the stencil printing process. Given all of the above it is critical that a precision stencil printing process be developed to support miniaturized electronic assembly.
This paper will be a summary of a significant amount of experimental data and process optimization techniques that were employed to establish precision SMT printing process. Our results indicate that the industry standard stencil aperture aspect ratio requirement of > 0.66 is an excellent rule of thumb. However, by optimizing printer setup with vacuum support, foil-less clamps, squeegee edge guards etc and assuring cleanliness and squeegee and stencil quality, we have been able to obtain acceptable stencil printing results with area ratios of 0.5 with Type III solder pastes. The work that was performed to achieve these results will be discussed in detail in the paper.
halogen-free, solder paste, solder, solder reliability, flux, solder quality, stencil printing
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Posted on 11 May 2009
