The effect of nickel on the strain evolution in chemical copper films

Bamberg, Simon; Perry, Laura K.; Muir, Bruce; Abuzir, Alaaedeen; Brüning, Frank; Brüning, Ralf

doi:10.1016/j.tsf.2012.07.039

Cited by 15 publications

(17 citation statements)

References 19 publications

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“…7 intersect close to this point, the lattice constants of the (hypothetically) unstrained films remain approximately independent of sample thickness. This contrasts with previous work, where upon varying the Ni content in the bath, the lines intersect near sin 2 ψ = 2/3 [8].…”

Section: Strain Analysis With Xrdcontrasting

confidence: 99%

“…These unpublished data confirm the assumption in Ref. [8] that the Ni atoms segregate at GBs. More specifically, these maps show that nickel precipitates are located along the lines and points where several GBs meet.…”

Section: Microstucture Evolution and Compositionsupporting

confidence: 90%

“…We have observed this relaxation previously in nickel-free electroless Cu films, whereas in films with small amounts of co-plated nickel this relaxation process is partially or fully suppressed [5,8]. Clearly, although Ni has been co-deposited, in the present films the Cu atoms in the GBs have retained some of their mobility.…”

Section: Time Evolution Of Average Film Stresssupporting

confidence: 48%

“…Co-deposition of about 1% Ni in the Cu film prevents compressive stress during deposition [5]. Building upon a model for the stress evolution in pure metal films with high atomic mobility [6], we proposed segregation of the Ni in the grain boundaries (GBs) as the mechanism that suppresses Cu adatom diffusion into the GBs during deposition [7], thus avoiding the compressive regime that in Ni-free deposits can cause blisters during plating [8,9]. In-situ measurements of the average film stress during electroless deposition were carried out for metal substrates and insulating substrates [10,11].…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Strain Analysis With Xrdcontrasting

confidence: 99%

Section: Microstucture Evolution and Compositionsupporting

confidence: 90%

Section: Time Evolution Of Average Film Stresssupporting

confidence: 48%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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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“…18 Bamberg et al indicate that various polyelectrolytes provide better adhesion of electroless Cu to glass than trimethoxy or triethoxy aminopropyl silanes. 4,19 They also discuss optimization of strain in the electroless Cu deposit by manipulating the properties of the plating solution such as addition of Ni 2+ to enhance adhesion. 4,14,19,20 Shingubara et al found that Au nanoparticle catalysts achieved a much higher density of coverage than colloidal Pd/Sn on a SiO 2 surface modified with APTES.…”

mentioning

confidence: 99%

Hybrid Method for Metallization of Glass Interposers

Ogutu

Fey

Børgesen

et al. 2013

J. Electrochem. Soc.

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Glass has gained interest as a material for interposer technology due to its low/adjustable thermal expansion coefficient, low cost, good dimensional stability and availability in large panels compared to silicon substrates. However, the metallization of glass constitutes a major challenge owing to the notoriously poor adhesion between glass and metals. In this work, strategies for improving the adhesion to the glass surface and for providing at the same time continuous coating of through glass holes (TGHs) are explored. As result, a hybrid approach for glass metallization based on sputtering of a thin Ti-Cu layer and subsequent coating by electroless Ni deposition is introduced and developed. The proposed approach takes advantage of the good adhesion of very thin sputtered films on glass surfaces and combines this with the ability of electroless plating to bridge center regions of high aspect TGHs that are inaccessible to metallization by sputtering. Robust layers deposited by the hybrid method, shown to continuously coat the surface and TGHs, allow for further Cu elctrodeposition on the way to final circuitry. Approaches explored for seeding, coating and further metallization are described in detail. Results of cross-section analysis, optical microscopy, and SEM are also presented.

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Effects of Sodium Hydroxyethyl Sulfonate on Improving the Ductility of the Copper Films Deposited by Electroless Plating from High‐Speed Plating Baths

Wang

et al. 2018

ChemistrySelect

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The copper films that electroless plated from the formaldehyde-based solutions frequently suffer from the internal stress. The internal stress leads to a poor ductility of the plated films. To lower internal stress and improve ductility of copper films, sodium hydroxyethyl sulfonate was used as a surfactant to promote the detachment of hydrogen bubbles. The folding tests showed that the copper film deposited from the solution containing 3 mL L À1 25% sodium hydroxyethyl sulfonate (EHS) had the best ductility. The internal stresses of the copper films were measured using X-ray diffraction technique and the stress decreased from 100 MPa to 30 MPa as the EHS concentration increased from 0 to 3 mL L À1 . Sodium hydroxyethyl sulfonate had little influence on the film morphology and crystal size. High plating rates (> 8 mm h À1 ) were obtained from the solution containing sodium hydroxyethyl sulfonate.

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The effect of nickel on the strain evolution in chemical copper films

Cited by 15 publications

References 19 publications

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

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

Hybrid Method for Metallization of Glass Interposers

Effects of Sodium Hydroxyethyl Sulfonate on Improving the Ductility of the Copper Films Deposited by Electroless Plating from High‐Speed Plating Baths

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