Effectiveness of conformal coatings on a PBGA subjected to unbiased high humidity, high temperature tests

Zhang, Kang; Pecht, Michael

doi:10.1108/13565360010352136

Cited by 18 publications

(8 citation statements)

References 7 publications

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“…However, there are many other polymer materials that may be used as conformal coatings for medical applications. The major conformal coating types are acrylic, epoxy, silicone, urethane and parylene (Zhang and Pecht, 2000). In medical applications for example silicone rubber, polyurethane and parylene C are used as conformal coatings (Meyer et al, 2001;Ziaie et al, 1996).…”

Section: Resultsmentioning

confidence: 99%

Effects of conformal coating on anisotropically conductive adhesive joints; a medical perspective

Kokko

Harjunpää²,

Haltia³

et al. 2009

Soldering &Amp; Surface Mount Technology

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If you would like to write for this, or any other Emerald publication, then please use our Emerald for Authors service information about how to choose which publication to write for and submission guidelines are available for all. Please visit www.emeraldinsight.com/authors for more information. About Emerald www.emeraldinsight.comEmerald is a global publisher linking research and practice to the benefit of society. The company manages a portfolio of more than 290 journals and over 2,350 books and book series volumes, as well as providing an extensive range of online products and additional customer resources and services.Emerald is both COUNTER 4 and TRANSFER compliant. The organization is a partner of the Committee on Publication Ethics (COPE) and also works with Portico and the LOCKSS initiative for digital archive preservation. AbstractPurpose -The purpose of this paper is to study epoxy and parylene C-coated samples. These coatings are used to protect the electronic devices from harsh environments. The effect of these conformal coatings on electronics reliability is considered. Design/methodology/approach -Epoxy coating is applied using dip coating and parylene C is applied with the vapour deposition polymerisation method. Test chip used is joined using flip-chip technology and an anisotropically conductive adhesive. Reliability of the test samples is evaluated in a constant humidity test, where test conditions are 858C and 85%RH. The test lasts 4,000 h. Failure analysis is carried out by cross-sectioning failed samples and using scanning electron microscopy for closer analysis. Findings -The results show variation in the reliability of adhesive joints with different conformal coating materials. Failure analysis highlights explicit failure mechanisms. Adhesion testing is also carried out on the test samples after constant humidity testing. The results of these reliability tests indicate clearly that parylene C is a more reliable choice of conformal coating than epoxy. Originality/value -The paper shows the influence of certain conformal coatings on the reliability of adhesive flip-chip joints. In medical applications, reliability plays an important role.

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Section: Resultsmentioning

confidence: 99%

Effects of conformal coating on anisotropically conductive adhesive joints; a medical perspective

Kokko

Harjunpää²,

Haltia³

et al. 2009

Soldering &Amp; Surface Mount Technology

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“…Conformal coating (CC) is a thin transparent layer with thickness of tens to hundreds micrometers, which is usually made of synthetic resin or plastic, applied on top of printed circuit boards (PCBs) [1], [2]. It serves to protect PCBs from environmental, electrical, mechanical and chemical effects, such as moisture, dust, mechanical stress, thermal stress, corrosion, solvents, chemical vapors and so on.…”

Section: Introductionmentioning

confidence: 99%

“…of PCBs, especially in automotive, avionics and military electronics [1]. For example, CC has proven to be an effective way to mitigate tin whisker to prevent arcing and short circuits.…”

Section: Introductionmentioning

confidence: 99%

Nondestructive Measurement of Conformal Coating Thickness on Printed Circuit Board With Ultra-High Resolution Optical Coherence Tomography

Shao

Chen

et al. 2019

IEEE Access

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Conformal coating (CC) is widely used to protect printed circuit board from corrosion, mold growth, and electrical failures. To ensure effective protection, the thickness of the CC layer needs to be well controlled. However, to date, the coating thickness is usually measured in a destructive way under microscopes. In this paper, we proposed to use optical coherence tomography (OCT) to measure the CC thickness nondestructively. Specifically, to obtain a good accuracy in thickness measurement, we constructed a spectral domain OCT with the ultra-high axial resolution to image the CC layer in three dimensions and developed an image segmentation algorithm to detect the CC layer from the OCT images. Finally, we evaluated the effectiveness of the proposed method by comparing it with the conventional method, and the results demonstrate that the measurement by our method is consistent with that by the microscope. This also indicates that OCT with high axial resolution can potentially be used to measure the CC thickness accurately and nondestructively. INDEX TERMS Optical coherence tomography, conformal coating, thickness measurement, image segmentation.

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“…The maximum solder reflow temperature (up to maximum 260 C) can also negatively impact the usable floor life performance designated by the moisture sensitivity levels of the IC packages [8]- [10]. The common failure mechanisms of traditional large size plastic ball-grid array (PBGA) packages include popcorning, as well as delamination and cracks between solder mask/copper interface in the multiple layer substrates [13], [30]. In fact, one of the challenges with the move to lead and halogen-free IC packages is the degradation of moisture sensitivity level (MSL) performance for large size PBGAs [14].…”

mentioning

confidence: 99%

The Influence of Substrate Enhancement on Moisture Sensitivity Level (MSL) Performance for Green PBGA Packages

Lin¹,

Pecht

Das

et al. 2006

IEEE Trans. Comp. Packag. Technol.

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As the electronics industry migrates to the leadand halogen-free (green) packages, many of the materials used in plastic ball-grid array (PBGA) substrates, in particular the molding compounds and die attaches, will have to be improved. The moisture sensitivity level (MSL) performance of the large nongreen PBGA packages are typically reduced by at least one JEDEC/IPC level at the lead-free reflow temperature of 260 C. Common failure mechanisms of traditional large size PBGA packages include popcorning, as well as delamination and cracks between the solder mask/copper interface in the multiple layer substrates.In this paper, the interfacial adhesion of traditional and advanced substrate materials and processing technologies are presented based on reliability tests of various PBGA packages subject to moisture soaking followed by reflow soldering at 260 C. It was found that substrate failures with delamination at the solder mask/copper interface were dramatically improved by introducing advanced materials and processes for multiple-layer substrates. However, the partial or full delamination at the mold compound/solder mask interface could still be observed after lead-free reflow soldering. There is an urgent need to improve the adhesion between mold compound/solder mask in order to achieve high MSL performance of large size and green PBGA packages.Index Terms-Green electronics, lead free soldering, moisture sensitivity level (MSL), plastic ball-grid array (PBGA).

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Effectiveness of conformal coatings on a PBGA subjected to unbiased high humidity, high temperature tests

Cited by 18 publications

References 7 publications

Effects of conformal coating on anisotropically conductive adhesive joints; a medical perspective

Effects of conformal coating on anisotropically conductive adhesive joints; a medical perspective

Nondestructive Measurement of Conformal Coating Thickness on Printed Circuit Board With Ultra-High Resolution Optical Coherence Tomography

The Influence of Substrate Enhancement on Moisture Sensitivity Level (MSL) Performance for Green PBGA Packages

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