On the mechanism of popcorn blistering in copper clad laminates.
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| Title: | On the mechanism of popcorn blistering in copper clad laminates. |
|---|---|
| Authors: | Kyeong-Won Seol, J.1, Chang-Hee Choi, J.2, Sangyum Kim, J.2, Seong Ho Son, J.3, Lee, Jong K.4 jkl103@mtu.edu |
| Source: | Journal of Adhesion Science & Technology. 10/1/2003, Vol. 17 Issue 10, p1331. 19p. |
| Subjects: | Laminated materials, Copper, Printed circuits, Thermal stresses, Energy dissipation |
| Abstract: | Printed circuit boards are subject to increasingly hostile environment, for example, to a higher reflow temperature with the new lead-free solders. Consequently, thermal stability of copper clad laminates, a major component in printed circuit boards, is a critical issue in electronic packaging industries. In order to understand thermal degradation behavior, popcorn blister tests were performed at high temperatures for three different brands of copper clads laminated with FR-4 epoxy-saturated glass fabrics. Regardless of the brand, all the specimens became defective with blisters at about 250 °C. Detailed examination of fracture morphology with a scanning electron and an optical interferometric microscope revealed that popcorn blisters started not at the interface between copper foil and epoxy resin but at the interface between epoxy resin and glass yarns inside the FR-4 fabric. Sizing agent, an organic lubricant used for glass fibers, is suspected for the initial breakdown of the interface between glass yarns and epoxy resin. As epoxy resin degraded through decomposition of amino-alcohol portion or some other reaction, the gas products then diffused to the yarn-resin interface area. When the temperature reached about 250 °C, the pressure of such gas pockets became strong enough to rupture the laminate under both tension and shear stresses or to advance the fracture through the epoxy via cleavage fracture. Fracture patterns displayed both river and hackle markings, typical characteristics of epoxy fracture. The river markings seemed to indicate cleavage fracture of the epoxy (mode I) which was in close contact with glass yarns. The hackle markings, on the other hand, suggested rupturing of epoxy under both tension and shear stresses (modes I and II), which were most likely caused by a change in the maximum principal tensile stress direction due to interlocked copper nodules. [ABSTRACT FROM AUTHOR] |
| Copyright of Journal of Adhesion Science & Technology is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
| FullText | Links: – Type: pdflink Text: Availability: 0 |
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| Header | DbId: egs DbLabel: Engineering Source An: 10921119 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: On the mechanism of popcorn blistering in copper clad laminates. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Kyeong-Won+Seol%2C+J%2E%22">Kyeong-Won Seol, J.</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Chang-Hee+Choi%2C+J%2E%22">Chang-Hee Choi, J.</searchLink><relatesTo>2</relatesTo><br /><searchLink fieldCode="AR" term="%22Sangyum+Kim%2C+J%2E%22">Sangyum Kim, J.</searchLink><relatesTo>2</relatesTo><br /><searchLink fieldCode="AR" term="%22Seong+Ho+Son%2C+J%2E%22">Seong Ho Son, J.</searchLink><relatesTo>3</relatesTo><br /><searchLink fieldCode="AR" term="%22Lee%2C+Jong+K%2E%22">Lee, Jong K.</searchLink><relatesTo>4</relatesTo><i> jkl103@mtu.edu</i> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Journal+of+Adhesion+Science+%26+Technology%22">Journal of Adhesion Science & Technology</searchLink>. 10/1/2003, Vol. 17 Issue 10, p1331. 19p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Laminated+materials%22">Laminated materials</searchLink><br /><searchLink fieldCode="DE" term="%22Copper%22">Copper</searchLink><br /><searchLink fieldCode="DE" term="%22Printed+circuits%22">Printed circuits</searchLink><br /><searchLink fieldCode="DE" term="%22Thermal+stresses%22">Thermal stresses</searchLink><br /><searchLink fieldCode="DE" term="%22Energy+dissipation%22">Energy dissipation</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Printed circuit boards are subject to increasingly hostile environment, for example, to a higher reflow temperature with the new lead-free solders. Consequently, thermal stability of copper clad laminates, a major component in printed circuit boards, is a critical issue in electronic packaging industries. In order to understand thermal degradation behavior, popcorn blister tests were performed at high temperatures for three different brands of copper clads laminated with FR-4 epoxy-saturated glass fabrics. Regardless of the brand, all the specimens became defective with blisters at about 250 °C. Detailed examination of fracture morphology with a scanning electron and an optical interferometric microscope revealed that popcorn blisters started not at the interface between copper foil and epoxy resin but at the interface between epoxy resin and glass yarns inside the FR-4 fabric. Sizing agent, an organic lubricant used for glass fibers, is suspected for the initial breakdown of the interface between glass yarns and epoxy resin. As epoxy resin degraded through decomposition of amino-alcohol portion or some other reaction, the gas products then diffused to the yarn-resin interface area. When the temperature reached about 250 °C, the pressure of such gas pockets became strong enough to rupture the laminate under both tension and shear stresses or to advance the fracture through the epoxy via cleavage fracture. Fracture patterns displayed both river and hackle markings, typical characteristics of epoxy fracture. The river markings seemed to indicate cleavage fracture of the epoxy (mode I) which was in close contact with glass yarns. The hackle markings, on the other hand, suggested rupturing of epoxy under both tension and shear stresses (modes I and II), which were most likely caused by a change in the maximum principal tensile stress direction due to interlocked copper nodules. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Journal of Adhesion Science & Technology is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1163/156856103769172779 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 19 StartPage: 1331 Subjects: – SubjectFull: Laminated materials Type: general – SubjectFull: Copper Type: general – SubjectFull: Printed circuits Type: general – SubjectFull: Thermal stresses Type: general – SubjectFull: Energy dissipation Type: general Titles: – TitleFull: On the mechanism of popcorn blistering in copper clad laminates. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Kyeong-Won Seol, J. – PersonEntity: Name: NameFull: Chang-Hee Choi, J. – PersonEntity: Name: NameFull: Sangyum Kim, J. – PersonEntity: Name: NameFull: Seong Ho Son, J. – PersonEntity: Name: NameFull: Lee, Jong K. IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 10 Text: 10/1/2003 Type: published Y: 2003 Identifiers: – Type: issn-print Value: 01694243 Numbering: – Type: volume Value: 17 – Type: issue Value: 10 Titles: – TitleFull: Journal of Adhesion Science & Technology Type: main |
| ResultId | 1 |
