Improved electro-mechanical performance of gold films on polyimide without adhesion layers

Pütz, Barbara; Schoeppner, Rachel L.; Глушко, Олександр; Bahr, David F.; Cordill, Megan J.

doi:10.1016/j.scriptamat.2015.02.005

Cited by 52 publications

(51 citation statements)

References 20 publications

(36 reference statements)

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“…A third film system consisting of a 50-nm Au film with a 10-nm Cr adhesion layer on PI was also deposited using the similar sputtering parameters but using 100-W DC power. This film system has been studied with other ex situ and in situ techniques and more information can be found in Putz et al (2015Putz et al ( , 2016. To demonstrate different adhesion theories, the 300-nm Au film with the 200-nm Cr overlayer was utilized as well as to two other gold systems.…”

Section: Methodsmentioning

confidence: 99%

“…This is an important concept for flexible electronic devices. The influence of brittle overlayers and adhesion layers has been studied for metal films with in situ XRD Marx et al, 2015b;Putz et al, 2015). However, further examination of how the brittle transparent conductors and encapsulation layers affect the metal conductors is necessary to determine how these brittle layers influence the electro-mechanical behavior of a flexible electronic device.…”

Section: Methodsmentioning

confidence: 99%

“…The unloaded resistance is the "real" value for a device after it has been unrolled, stretched, or bent into the application shape. It takes into account any grain growth, crack bridging, or viscoelastic recovery of the substrate Glushko et al, 2014;Putz et al, 2015). Using OLM or SEM, in situ methods provide information about the COS, crack spacing evolution, and even the buckling strain of brittle films.…”

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confidence: 99%

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Electro-Mechanical Testing of Conductive Materials Used in Flexible Electronics

2016

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The use of flexible electronics has increased in recent years. In order to have robust and long lasting flexible displays and sensors, the combined electro-mechanical behavior needs to be assessed. The most common method to determine electrical and mechanical behavior of conductive thin films used in flexible electronics is the fragmentation test or uniaxial tensile straining of the film and substrate. When performed in situ, fracture and deformation behavior can be determined. The use of in situ electrical resistance measurements can be informative about the crack onset strain of brittle layers, such as transparent conductors, or the stretchability of metal interconnects. The combination of in situ electrical measurements with in situ X-ray or confocal laser scanning microscopy can provide even more information about the failure mechanisms of the material systems. Lattice strains and stresses can be measured with X-rays, while cracking and buckle delaminations can be studied with confocal laser scanning microscopy. These new combinations of in situ methods will be discussed as well as methods to quantify interfacial properties of conductive thin films on polymer substrates. The combined techniques provide valuable correlated electrical and mechanical data needed to understand failure mechanisms in flexible devices.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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confidence: 99%

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Electro-Mechanical Testing of Conductive Materials Used in Flexible Electronics

2016

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“…The laminated Cu foil is usually 18-35 µm thick to sustain sufficient mechanical strength; however, this thickness issue may make CCL technology unsuitable for fine-pitched wearable and portable devices. An alternative method is to grow a thin metallic layer directly on the PI using sputtering [21][22][23] or electrochemical…”

Section: Introductionmentioning

confidence: 99%

Study of Surface Metallization of Polyimide Film and Interfacial Characterization

Lin

Chen

2017

Metals

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Nickel (Ni) metallization of polyimide (PI) was performed using a solution-based process including imide-ring opening reactions, the implanting of Ni ions, the reduction of catalytic Ni nanoparticles, and the electroless deposition of a Ni film. The start-up imide-ring opening reaction plays a crucial role in activating inert PI for subsequent Ni implanting and deposition. A basic treatment of potassium hydroxide (KOH) is commonly used in the imide-ring opening reaction where a poly(amic acid) (PAA) layer forms on the PI surface. In this study, we report that the KOH concentration significantly affects the implanting, reduction, and deposition behavior of Ni. A uniform Ni layer can be grown on a PI film with full coverage through electroless deposition with a KOH concentration of 0.5 M and higher. However, excessive imide-ring opening reactions caused by 5 M KOH treatment resulted in the formation of a thick PAA layer embedded with an uneven distribution of Ni nanoparticles. This composite layer (PAA + Ni) causes wastage of the Ni catalyst and degradation of peel strength of the Ni layer on PI.

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“…The cracking failure has been thoroughly addressed with several testing techniques, the most popular being tensile straining [5][6][7][8][9] and bending. These techniques work well for brittle films, [24][25][26] but require an extensive amount of straining for ductile films [27] or an overlayer to induce delamination at lower levels of strain. Techniques used to evaluate the adhesion of thin films to rigid substrates have advanced our understanding of adhesion and its mechanisms.…”

Section: Introductionmentioning

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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Improved electro-mechanical performance of gold films on polyimide without adhesion layers

Abstract: Graphical abstract

Cited by 52 publications

References 20 publications

Electro-Mechanical Testing of Conductive Materials Used in Flexible Electronics

Electro-Mechanical Testing of Conductive Materials Used in Flexible Electronics

Study of Surface Metallization of Polyimide Film and Interfacial Characterization

Thin Film Adhesion of Flexible Electronics Influenced by Interlayers

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