Papers about head-in-pillow
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
[Permanent Link to this Paper ]
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 Ed Briggs , Dr. Ronald C. Lasky
Chinese version of Best Practices Reflow Profiling for
Lead-Free SMT Assembly.
CHINESE LANGUAGE, graping, head-in-pillow, Voids, solder balling, solder beading, tombstoning, reflow profile, solder defects
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Posted on 22 Mar 2010
by Dr. Ronald C. Lasky , Ed Briggs
The combination of higher lead-free process temperatures, smaller print deposits, and temperature restraints on electrical components has created difficult challenges in optimizing the reflow process. Not only are the electronic components and the PWB at risk, but the ability to achieve a robust solder joint becomes difficult, especially if the PCB is thermally massive. In addition, the constant miniaturization of electronic components, hence smaller solder paste deposits, may require the use of smaller particle-sized powders. Both the small solder paste deposits and small particle size result in a large surface area-to-volume ratio that challenges the solder paste's flux to effectively perform its fluxing action. The possible resulting surface oxidation can lead to voiding, graping, head-in-pillow, and other defects. Smaller components are also more susceptible to tombstoning and defects related to solder paste slump.
This paper is a summary of best practices in optimizing the reflow process to meet these challenges of higher reflow temperatures, smaller print deposits, decreased powder particle size, and their affect on the reflow process. It also discusses trouble-shooting of the most common defects in lead-free reflow, such as tombstoning, solder beading/balling, residue discoloration, voiding, graping, and head in pillow.
solder defects, reflow profile, tombstoning, solder beading, solder balling, Voids, head-in-pillow, graping
[Permanent Link to this Paper ]
Posted on 1 Jun 2009
by Timothy Jensen , Dr. Ronald C. Lasky
Chinese version of Challenges of Implementing a
Halogen-Free PCB Assembly Process.
oxidation barrier, activator, pb-free, reflow, graping, head-in-pillow, halide-free, halogen-free, halogens, CHINESE LANGUAGE
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Posted on 22 Mar 2010
by Dr. Ronald C. Lasky , Timothy Jensen
The electronics industry continues to strive to provide more environmentally friendly products. This movement is partly due to legislation from various countries, partly due to public outcry from well publicized 3rd world recycling practices, and partly due to non-government organizations (NGOs) testing and publishing information on electronic devices regarding their content of various toxic materials. One set of materials targeted for reduction and eventual elimination are halogenated compounds. Halogens are found in plastics for cables and housings, board laminate materials, components, and soldering fluxes. Replacing these halogenated compounds can have a dramatic affect on the PCB
assembly process. In this paper those challenges will be discussed as well as techniques and practices that will help ensure high end of line yields and continued reliability.
oxidation barrier, activator, pb-free, reflow, graping, head-in-pillow, halide-free, halogen-free, halogens
[Permanent Link to this Paper ]
Posted on 4 Mar 2010
by Timothy Jensen
Chinese version of Head-In-Pillow: The Defect that Caught Us Napping.
head-in-pillow, CHINESE LANGUAGE
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Posted on 22 Mar 2010
by Timothy Jensen
Although the head-in-pillow defect is not totally new, the high frequency of occurrence is. This defect is a direct result of the convergence of product miniaturization and the transition to
Pb-free solders .
head-in-pillow
[Permanent Link to this Paper ]
Posted on 4 Mar 2010
by ICA
A Contract Equipment Manufacturer conducted an
independent “live”production line test of two solder
pastes and confirmed the age-old adage “You get what
you pay for.”Today’s electronics industry derives its
strength from global marketplace competitive pricing
but beyond price is the overall impact of quality and
production achieved by using technologically superior
products — even if they cost a little more.Solder paste,
an often-undervalued component necessary for elec-
tronics manufacturing,generated significant savings by
achieving higher yields, reducing solder paste scrap,
and eliminating nitrogen processing costs.
halogen-free solder paste, halide-free solder paste, halogen-free, halide-free, head, pillow, head-in-pillow, head in pillow defect, NC-SMQ92J
[Permanent Link to this Paper ]
Posted on 8 Mar 2010
by Jim Hisert , Brandon Judd
White Paper Video
Next Generation PoP Pastes for Electronics Assembly
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Package-on-package (PoP) technology allows two or more electronic components to be stacked vertically, which saves space and allows our portable gadgets to continue getting smaller year after year. A relatively new form of solder paste called "PoP Paste" has been developed specifically for this application.
There are fundamental differences between PoP pastes and the traditional solder pastes, which are designed for printing applications. This paper will highlight the differences between these solder pastes and talk about the characteristics needed by PoP pastes to increase transfer efficiency, eliminate head-in-pillow defects, and provide excellent solder wetting. If these three criteria are met, solder joint reliability will follow.
head-in-pillow, Dipping Flux, Dipping Paste, package on package, PoP Solder Paste, BGA
[Permanent Link to this Paper ]
Posted on 15 Oct 2009
by Dr. Ning-Cheng Lee , Dr. Arnab Dasgupta, Dr. Runsheng Mao, Dr. Yan Liu
Electronic industry has been driven toward lead-free by RoHS (Restriction of Hazardous Substances Directive) which is in force since 2006. Recently REACH (Registration, Evaluation and Authorization of Chemicals) further drives the industry toward halogen-free. As a result, solder pastes for PCB assembly are required or desired to be both lead-free and halogen-free. Lead-free solder alloys in general wet poorer than tin-lead due to the higher surface tension of the former alloys. In the mean time, halogen-free fluxes typically also wet poorer than the more powerful halogen-containing fluxes. Consequently, the lead-free and halogen-free solder paste products that emerged inevitably suffer from a considerably inferior soldering performance than that of conventional halogen-containing tin-lead solder pastes. The deficiencies include poor wetting, solder balling, voiding, graping, head-in-pillow, etc. This gap is particularly significant for fine-pitch applications where the impact of oxidation is more profound. Furthermore, the higher soldering temperature of the higher melting lead-free alloys also aggravates the challenge of in-circuit test for no- clean processes, mainly due to the difficulty for probe to penetrate through the toughened flux residue. Although use of inert reflow atmosphere may alleviate some of the problems, the higher cost of it is prohibitive for most of the manufacturing firms. In this work, a halogen-free lead-free no-clean solder paste system, Indium8.9HF series, has been developed. It exhibits superior oxidation tolerance, thus assures superior resistance against graping, head-in-pillow, solder balling, voiding, and poor wetting for miniaturized electronic applications. In spite of the immense challenge in material science, this system also shows outstanding probe testability, in addition to its very good printability, non- slump, SIR, and ECM performance. The superior performance of this Indium8.9HF system effectively sealed the gap caused by lead-free and halogen-free requirements.
lead-free, halogen-free, no-clean, solder, solder paste, miniaturization, graping, head-in-pillow, voiding, solder balling, probe testability, ICT, oxidation
[Permanent Link to this Paper ]
Posted on 1 Jan 2009
by Amanda Hartnett , Dr. Ronald C. Lasky , Timothy Jensen
Chinese version of Soldering Challenges in a Halogen-Free PCB Assembly Process
halogen-free, halide-free, solder, soldering, graping, flux, head-in-pillow, hole-fill, CHINESE LANGUAGE
[Permanent Link to this Paper ]
Posted on 13 May 2011
by Timothy Jensen , Dr. Ronald C. Lasky , Amanda Hartnett
Flame retardants have played an important role in the safety of many products. It is safe to say that thousands of lives have been saved by flame retardants. Flame retardants are used in products as varied as children's pajamas to electronics assemblies. Some of the more successful flame retardants are halogenated compounds. Halogenated materials are found in polyvinyl chloride (PVC), brominated flame retardants (BFRs), chlorinated flame retardants (CFRs), as well as in fluxes used in the electronics assembly industry. Product does not contain any halogenated compounds. However, that is not exactly how the term is used for soldering fluxes. A flux that is classified as
halide-free by the IPC/J-STD-004 is actually only free of ionic halides.
hole-fill, head-in-pillow, flux, graping, soldering, solder, halide-free, halogen-free
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Posted on 10 Mar 2010
by Dr. Ning-Cheng Lee , Dr. Yan Liu, Pamela Fiacco
Head-in-pillow (HIP) is ailing the electronic industry when assembling BGAs or CSPs onto PCBs. It is caused by warpage of components or boards at reflow process, and is aggravated by oxidation. Methods for assessing the potential for occurrence of HIP are highly desired by the industry. Besides using BGA rework station followed by tedious dye and pry treatment, two other simpler methods are introduced in this work, Tiny Dot Paste method and Ball Onto Paste method. The Tiny Dot Paste method is stressed on the assessment of oxidation barrier capability of solder paste, while Ball Onto Paste method assesses combined capability of oxidation resistance and excessive fluxing capacity. Both methods are quick, easy, and close simulation, with the latter being better in real process simulation. Prevention of HIP can be accomplished by (1) designing packages without warpage, (2) printing more paste, (3) dipping solder paste or flux, (4) using inert reflow atmosphere, (5) reducing reflow temperature, (6) placing heat shield on BGA or CSP, (7) avoiding using water soluble solder paste for BGA bumped with no-clean process, (8) using solder bumps or solder powder with oxidation resistant alloy, (9) using fluxes with high oxidation barrier capability and high fluxing capacity. Among all options listed above, using solder paste with high oxidation barrier capability and high fluxing capacity is considered the most easily implemented approaches.
head-in-pillow, solder, soldering, reflow, SMT, solder paste, BGA, CSP
[Permanent Link to this Paper ]
Posted on 24 Jan 2011
