Copper/Epoxy Joints in Printed Circuit Boards: Manufacturing and Interfacial Failure Mechanisms

Nothdurft, Philipp; Rieß, Gisbert; Kern, Wolfgang

doi:10.3390/ma12030550

Cited by 37 publications

(14 citation statements)

References 102 publications

(127 reference statements)

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“…The deposit volume V p was calculated from the averaged d(r) data by numerical integration of the product, d(r) × 2πr over r, in the limits from r = 0 to an upper value r max , where d(r max ) was virtually zero. In certain regions, d may be in error by Weak adhesion strength of copper/epoxy joints, for example, in printed circuit boards, has been an issue for decades, see, for example, the review reported in Nothdurft et al [42]…”

Section: Instrumentationmentioning

confidence: 99%

Evidence of ionic film deposition from single‐filament dielectric barrier discharges in Ar–HMDSO mixtures

Bröcker

Perlick

Klages

2020

Plasma Processes & Polymers

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The short residence time of Ar-HMDSO (Ar-hexamethyldisiloxane) gas mixtures rapidly flowing across atmospheric-pressure, glow-type, single-filament dielectric barrier discharges is utilized to accomplish thin-film deposition via a purely ionic route. A comparison of thin-film volumes obtained from profilometry, on the one hand, and from the transferred charge, on the other hand, enables to evaluate the mass of the ions contributing to the film growth. For HMDSO fractions at the lower end of the studied range of molar fractions, 50 ppm, pentamethyldisiloxanyl cations (Me 3 SiOSiMe 2 + , PMDS +), generated from the monomer via Penning ionization by Ar(1s) species, are mainly responsible for film formation. For HMDSO fractions growing beyond 1,000 ppm, ionic oligomerization processes by reactions of PMDS + with HMDSO molecules result in a 2.5-fold increase of the average deposited ion mass.

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Section: Instrumentationmentioning

confidence: 99%

Evidence of ionic film deposition from single‐filament dielectric barrier discharges in Ar–HMDSO mixtures

Bröcker

Perlick

Klages

2020

Plasma Processes & Polymers

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“…48 Chemical information at the interfaces between the metal materials and coating/packaging polymers in FPCs and other microelectronics parts is critical in terms of adhesion, mechanical strength, and insulation, and there is a great need for this analysis. 49–52…”

Section: Introductionmentioning

confidence: 99%

Novel Method for High-Spatial-Resolution Chemical Analysis of Buried Polymer-Metal Interface: Atomic Force Microscopy-Infrared (AFM-IR) Spectroscopy with Low-Angle Microtomy

Baden

2021

Appl Spectrosc

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There is a great need for the analysis of the chemical composition, structure, functional groups and interactions at polymerâmetal interfaces in terms of adhesion, corrosion, and insulation. Although atomic-force-microscopy-based infrared spectroscopy (AFM-IR) can provides chemical analysis with nanoscale spatial resolution, it generally requires to thin a sample to be placed on a substrate that has low absorption of infrared light and high thermal conductivity, which is often difficult for samples that contain hard materials like metals. This study demonstrates that the combination of AFM-IR with low-angle microtomy (LAM) sample-preparation can analyze buried polymerâmetal interfaces with higher spatial resolution than that with the conventional sample-preparation of a thick vertical cross-section. In the LAM of a polymer layer on a metal substrate, the polymer layer is tapered to be thin in the vicinity of the interface, and thus, sample thinning is not required. An interface between an epoxyacrylate layer and copper wire in a flexible printed circuit cable was measured using this method. A carboxylate interphase layer with a thickness of ~130 nm was clearly visualized at the interface, and its spectrum was obtained without any signal contamination from the neighboring epoxyacrylate, which was difficult to achieve on a thick vertical cross-section. The combination of AFM-IR with LAM is a simple and useful method for high-spatial-resolution chemical analysis of buried polymerâmetal interfaces.

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“…The adhesion between epoxy resin and metals is of great relevance in diverse industry sectors, such as automotive, aerospace, energy, and electronics [ 1 , 2 , 3 ]. Particularly, the fabrication of metal/epoxy/metal joints and metal/epoxy coatings usually requires a previous treatment of the metal surface in order to achieve good adhesion strength.…”

Section: Introductionmentioning

confidence: 99%

“…The resulting improvement of the copper/epoxy adhesion strength has been attributed to the nucleation of acicular CuO crystals on top of the Cu 2 O layer [ 4 ]. However, the Cu/epoxy bonds prepared using this protocol present some drawbacks, such as their poor durability in acidic environments [ 1 , 4 ] due to corrosion of the oxide, causing delamination problems. The use of aggressive agents in chemical treatments may create a large volume of hazardous and contaminant wastes that can negatively affect natural environment and human health.…”

Section: Introductionmentioning

confidence: 99%

Improved Copper–Epoxy Adhesion by Laser Micro- and Nano-Structuring of Copper Surface for Thermal Applications

et al. 2021

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The objective of this work is the enhancement of metal-to-metal bonding to provide high thermal conductivity together with electrical insulation, to be used as heat sinks at room and cryogenic temperatures. High thermal conductive metal (copper) and epoxy resin (Stycast 2850FT) were used in this study, with the latter also providing the required electrical insulation. The copper surface was irradiated with laser to induce micro- and nano-patterned structures that result in an improvement of the adhesion between the epoxy and the copper. Thus, copper-to-copper bonding strength was characterized by means of mechanical tensile shear tests. The effect of the laser processing on the thermal conductivity properties of the Cu/epoxy/Cu joint at different temperatures, from 10 to 300 K, is also reported. Using adequate laser parameters, it is possible to obtain high bonding strength values limited by cohesive epoxy fracture, together with good thermal conductivity at ambient and cryogenic temperatures.

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Copper/Epoxy Joints in Printed Circuit Boards: Manufacturing and Interfacial Failure Mechanisms

Cited by 37 publications

References 102 publications

Evidence of ionic film deposition from single‐filament dielectric barrier discharges in Ar–HMDSO mixtures

Evidence of ionic film deposition from single‐filament dielectric barrier discharges in Ar–HMDSO mixtures

Novel Method for High-Spatial-Resolution Chemical Analysis of Buried Polymer-Metal Interface: Atomic Force Microscopy-Infrared (AFM-IR) Spectroscopy with Low-Angle Microtomy

Improved Copper–Epoxy Adhesion by Laser Micro- and Nano-Structuring of Copper Surface for Thermal Applications

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