Comparison of Curvature and X-Ray Methods for Measuring of Residual Stresses in Hard PVD Coatings

Kõo, Jakub; Gregor, Andre; Ryabchikov, A. I.; Sergejev, Fjodor; Traksmaa, Rainer; Kulu, Priit

doi:10.4028/www.scientific.net/msf.681.455

Cited by 9 publications

(13 citation statements)

References 10 publications

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“…For chemical vapor deposition, physical vapor deposition, and sputtering the film stress found by these two methods usually agrees. [9][10][11] In the present case, significant differences can be observed in the more complex electroless deposition process.…”

mentioning

confidence: 83%

Stress and Strain Evolution in Electroless Copper Films Evaluated with X-ray Diffraction and Substrate Curvature

Sharma

Brüning

Brown

et al. 2013

J. Electrochem. Soc.

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The scope of electroless copper plating technology is evolving to applications with smaller structures and smoother substrates, where adhesion of the copper film can be hard to achieve. The extent to which different factors, such as film stress and hydrogen evolution, contribute to delamination and blister formation on smooth organic substrates is a topic of active discussion. Stress and strain evolution is reported here for a nickel-and formaldehyde-free formulation for a range of plating bath temperatures. X-ray diffraction, with the sin 2 ψ method, was used to monitor the strain within the copper crystallites during and after their growth. Substrate bending measurements were used to detect the average stress of the film. This technique indicates a 60 nm wide zone of tensile stress at the interface between substrate and film. During and immediately following deposition, the average substrate stress is more compressive than implied by the strain of the Cu crystallites. After deposition, the additional compressive stress seen by substrate bending relaxes until it matches the Cu crystallite strain. Furthermore, the thermal substrate contraction effect upon termination of plating is considered, since it may influence the film adhesion.Electroless copper films, widely used in the printed circuit board industry, are currently being optimized for providing interconnects for future generations in integrated circuit (IC) substrates. For such applications, the industry is moving toward specifying limits for stress in electroless copper deposits. Nickel is frequently added to electroless copper baths because it controls the film stress 1 and because it reduces hydrogen evolution during deposition. 2,3 However, co-deposited nickel reduces the conductivity of the copper deposits, which may be a problem in high-end applications that require confined current paths during the subsequent galvanic copper plating. Further, nickel as an additive and formaldehyde as the reducing agent are incompatible with the desire to employ green chemistry processes wherever possible. In order to produce highly reliable films within these constraints, one has to monitor the factors that are known to limit film adhesion, the film stress 4 and co-deposited hydrogen. 2 Hydrogen, co-deposited at typical pressures of 70 MPa in grain boundaries, 5 reduces the film ductility and adhesion. 2,6-8Here we present X-ray diffraction and substrate curvature measurements that are sensitive to the strain of the copper crystallites and the average stress of the copper film, respectively. These measurements were carried out during and after film deposition from a bath formaldehyde-free and nickel-free at different temperatures. For chemical vapor deposition, physical vapor deposition, and sputtering the film stress found by these two methods usually agrees. 9-11 In the present case, significant differences can be observed in the more complex electroless deposition process. ExperimentalThe Cu films were produced from an electroless nickel-free bath containing 3 g/...

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mentioning

confidence: 83%

Stress and Strain Evolution in Electroless Copper Films Evaluated with X-ray Diffraction and Substrate Curvature

Sharma

Brüning

Brown

et al. 2013

J. Electrochem. Soc.

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“…The obtained mean residual stresses in the coatings were calculated from the deflection of the plate, where the equation is based on Stoney's formula to account for biaxial stresses [5,6].…”

Section: Experimental Methodsmentioning

confidence: 99%

Hydroxyapatite/Polyvinyl Alcohol Composite <i>In Situ</i> Synthesis for Hydrogel Formation<sup></sup>

Vojevodova

Loča

2016

KEM

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It is well known that polyvinyl alcohol hydrogel-based (PVA-H) biomaterials are promising materials for damaged articular cartilage replacement, but their application for bone tissue engineering is restricted due to insufficient mechanical properties. Thus, to meet the demands of the bone substitute material, PVA-H are reinforced with hydroxyapatite (HAp) crystals. The current research is focused on the preparation of nanosized hydroxyapatite/polyvinyl alcohol (n-HAp/PVA) composite material that mimics the microstructure and mechanical properties of natural bone tissue. The aim of this work is to determine the impact of various technological parameters of n-HAp/PVA composite in situ synthesis on the chemical purity of final product. Obtained results confirmed that the main inorganic phase of the composite material is HAp with an average crystallite size of 20.39 nm, however β-tricalcium phosphate (β-TCP) and CaO phases are also present. Obtained results showed that it is possible to decrease the amount of potentially harmful by-products, e.g. CaO in the composite material from 1.57wt% to 0.32wt% by increasing the homogenization speed of starting suspension from 400 rpm up to 7000 rpm, though the main influence on the obtained products chemical purity has 5wt% polyvinyl alcohol aqueous solution. Based on the results, it is concluded that the combination of starting suspension stirring temperature, homogenization speed and homogenization time of 23°C, 7000 rpm and 2 min, respectively, allows to obtain nanocomposite with the lowest amount of impurities (HAp: 98.08wt%; β-TCP: 1.60wt%; CaO: 0.32wt%).

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“…Plates (Fig. 1b) are only deposited from one side and should be placed gripped with a claw in the fixing device made of carbon steel [3]. Depending on the deflection of the plate, modified Stoney's formula will account for biaxial stresses [6].…”

Section: Evaluation Of Residual Stresses In the Coatingmentioning

confidence: 99%

“…One batch of vertically fixed plates was prepared by depositing a unilateral coating on the front surface and the other batch of plates, by depositing it on the back surface. Thus a considerable amount of the vapoured target material was deposited on the fixing device as well [3]. On the other hand, using the tubular substrate, most of the coating was deposited on the outer surface of the tube (a small part of the coating was deposited on the nozzle) it is possible to estimate the values of residual stresses in coatings on cylindrical surfaces (e.g.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Residual Stresses in PVD Coatings by means of Tubular Substrate Length Variation

Peetsalu

Kübarsepp

Mikli

et al. 2018

Materials Research Proceedings

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Comparison of Curvature and X-Ray Methods for Measuring of Residual Stresses in Hard PVD Coatings

Cited by 9 publications

References 10 publications

Stress and Strain Evolution in Electroless Copper Films Evaluated with X-ray Diffraction and Substrate Curvature

Stress and Strain Evolution in Electroless Copper Films Evaluated with X-ray Diffraction and Substrate Curvature

Hydroxyapatite/Polyvinyl Alcohol Composite <i>In Situ</i> Synthesis for Hydrogel Formation<sup></sup>

Evaluation of Residual Stresses in PVD Coatings by means of Tubular Substrate Length Variation

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