Measuring electro-mechanical properties of thin films on polymer substrates

Cordill, Megan J.; Глушко, Олександр; Kreith, Josef; Marx, Vera Maria; Kirchlechner, Christoph

doi:10.1016/j.mee.2014.08.002

Cited by 46 publications

(35 citation statements)

References 26 publications

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“…It has been shown that a Ta interlayer can greatly improve the adhesion of Au to PI. [44][45][46] In these cases, only necking was detected with no buckle delamination because the critical buckling stress was not met. The formation of long straight buckles perpendicular to the straining direction after unloading from a large applied tensile strain is of interest.…”

Section: Discussionmentioning

confidence: 99%

Thin Film Adhesion of Flexible Electronics Influenced by Interlayers

et al. 2016

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With the emergence of flexible electronics in the fields of medical sensors and foldable displays, there is a need to understand the interfacial behavior between active conducting elements and compliant polymer substrates, on which the devices are fabricated. Compression induced delamination is one technique that can be utilized to assess interfacial adhesion of flexible substrates that only uses the resulting buckle dimensions to quantitatively evaluate adhesion. It is found that spontaneous buckles formed in the Au film without the interlayer after deposition, while external loading is required to delaminate the Au film with the Ta adhesion layer indicating a higher adhesion energy.

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Section: Discussionmentioning

confidence: 99%

Thin Film Adhesion of Flexible Electronics Influenced by Interlayers

et al. 2016

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“…The combination of electrical and mechanical in-situ methods provides a better view on how the electrical behavior can be affected by the mechanical damage, especially of ductile films. These in-situ-squared (in-situ 2 ) methods [10] will soon become standardized testing methods for flexible electronics. In this contribution the basic failure mechanisms observed in metallizations on flexible substrates are overviewed for monotonic tensile, cyclic tensile, and cyclic bending tensile and compressive loading conditions.…”

Section: Introductionmentioning

confidence: 99%

33-2:Invited Paper: Evaluating Reliability of Flexible Electronic Materials with Combined Electro-Mechanical Testing Techniques

Cordill

Berger

Jörg

2016

SID Symposium Digest of Technical Papers

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Flexible electronics can have a long lifetime only if they are electrically and mechanically robust. When the device fails mechanically through the formation of the cracks or deformation, the electrical conductivity is influenced. Materials used in flexible electronics can be tested to determine their electro-mechanical behavior using tensile straining and bending methods. These methods are best employed with in-situ observation techniques. Different testing approaches will be described for brittle and ductile films on polymer substrates which are used to determine the reliability of flexible devices.

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“…In-situ measurements of the average film stress during electroless deposition were carried out for metal substrates and insulating substrates [10,11]. The mechanical state of Cu films on insulating substrates has to be considered carefully [12].…”

Section: Introductionmentioning

confidence: 99%

Properties of electroless Cu films optimized for horizontal plating as a function of deposit thickness

Sharma

Brüning

Nguyen

et al. 2015

Microelectronic Engineering

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The properties of electroless films produced from a bath designed for horizontal plating, the preferred technology for high production volumes in printed circuit board metallization, are reported. Film thickness, substrate type and electrolyte temperature were varied. Formation of a continuous layer of copper film is correlated with a change in the visual and spectroscopic appearance. Grain orientation is random in thin films and a 〈110〉 texture develops with increasing thickness. The plating solution contains Cu and Ni ions. Nickel co-deposits in copper films in the form of Ni hydroxide, and its concentration decreases from about 6% in the vicinity of the substrate to about 1% at the film surface. Film stress and strain were measured by substrate curvature and X-ray diffraction, respectively. Both stress and strain decrease as the film thickness increases. Stress remains tensile throughout during deposition and during relaxation, promoting film adhesion by preventing blisters. After deposition, stress relaxes first towards compressive and then towards tensile. The stress, the stress relaxation and the Ni concentration are high at the base of the film. We attribute this to the higher volume fraction of grain boundaries (smaller grain size) in this region.

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Measuring electro-mechanical properties of thin films on polymer substrates

Abstract: Graphical abstract

Cited by 46 publications

References 26 publications

Thin Film Adhesion of Flexible Electronics Influenced by Interlayers

Thin Film Adhesion of Flexible Electronics Influenced by Interlayers

33-2:Invited Paper: Evaluating Reliability of Flexible Electronic Materials with Combined Electro-Mechanical Testing Techniques

Properties of electroless Cu films optimized for horizontal plating as a function of deposit thickness

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