Strain in electroless copper films monitored by X-ray diffraction during and after deposition and its dependence on bath chemistry

Brüning, Ralf; Muir, Bruce; McCalla, Eric; Lempereur, Émilie; Brüning, Frank; Etzkorn, Johannes

doi:10.1016/j.tsf.2011.02.016

Cited by 17 publications

(15 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The change in stress state after baking or long sit times is due to the metastable nature of the deposited Cu grains, which tend to coarsen into larger grains with time to eliminate grain boundaries and reduce overall interfacial energy of the system. This phenomenon of a compressive deposit relaxing to a tensile state has been reported previously for electroless and electroplated Cu films [2,3]. For a given plating current density, the electrolytic Cu plating solution impacted the magnitude and evolution of stress in the plated deposit.…”

Section: Cu Deposit Stress Resultssupporting

confidence: 76%

Improvement of substrate and package warpage by copper plating process optimization

Bchir

Jomaa

Kim

et al. 2014

2014 IEEE 64th Electronic Components and Technology Conference (ECTC)

View full text Add to dashboard Cite

High substrate warpage can lead to unacceptable yield loss during chip attach in assembly, and cause high yield fallout during package mount on the circuit board. For the first time, through this work, the electrolytic copper (Cu) plating process in substrate manufacturing was shown to contribute significantly to package warpage. For a 14x14mm package, reducing the Cu plating rate (within the manufacturing operating window) resulted in 21% package warpage reduction, while a change in Cu plating solution provided an additional 6% reduction (total 27% reduction). Hence the Cu plating process and solution must be carefully scrutinized to minimize package warpage, specifically for thin packages (<1mm) where Cu stresses become a large contributing factor.

show abstract

Section: Cu Deposit Stress Resultssupporting

confidence: 76%

Improvement of substrate and package warpage by copper plating process optimization

Bchir

Jomaa

Kim

et al. 2014

2014 IEEE 64th Electronic Components and Technology Conference (ECTC)

View full text Add to dashboard Cite

show abstract

“…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%

“…c o m / l o c a t e / m e e q ! and the direction normal to the film [5]. The sample was tilted by ψ about the χ-axis, located in the scattering plane and perpendicular to the scattering vector.…”

Section: Contents Lists Available At Sciencedirectmentioning

confidence: 99%

“…During plating films without nickel are in a compressive state that can cause blisters. 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].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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

Sharma

Brüning

Nguyen

et al. 2015

Microelectronic Engineering

Self Cite

View full text Add to dashboard Cite

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.

show abstract

“…The strain evolution of films was determined based on three types of electrolyte. Within the experimental ambiguity, the correlation among stress and strain for the Cu films approves with the properties of bulk polycrystalline Cu [61]. The coating of Cu on particles of B 4 C is required in order to synthesize metal-ceramic composites with improved sinterability and dispersability.…”

Section: Nanocharacteristics Of Electroless Coppermentioning

confidence: 95%

Electroless Deposition of Nanolayered Metallic Coatings

Sudagar¹,

Tamilarasan²,

Sanjith³

et al. 2017

Nanoscaled Films and Layers

View full text Add to dashboard Cite

Electroless metallic coating is referred as the deposition of a substrate material by the process of chemical or autocatalytic reduction of aqueous metal ions deposited to a substrate material without any external supply of power. Electroless nickel alloys are generally considered synonymous to the word "electroless coating" as ~90% of productions in industries are of this alloy coating. Rest of the electroless metallic coatings includes gold, copper, palladium, cobalt, silver, etc. These electroless metallic coatings (other than electroless nickel coatings) are also one of the vibrant areas in the field of materials properties and surface engineering research. From the year 2000 to till date, nearly 1000 SCI indexed research papers were published on this topic. However, no comprehensive studies about the recent progress on this topic were reported elsewhere so far. In this context, the present chapter aims to give a complete overview on various aspects of the rest of the electroless metallic nanocoatings/layer as a whole. More importance will be on the recent developments of the nanocharacteristics and future scopes.

show abstract

Strain in electroless copper films monitored by X-ray diffraction during and after deposition and its dependence on bath chemistry

Cited by 17 publications

References 13 publications

Improvement of substrate and package warpage by copper plating process optimization

Improvement of substrate and package warpage by copper plating process optimization

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

Electroless Deposition of Nanolayered Metallic Coatings

Contact Info

Product

Resources

About