Thermal reliability of fine pitch Cu-Cu bonding with self assembled monolayer (SAM) passivation for Wafer-on-Wafer 3D-Stacking

2011 ◽  
Author(s):  
L. Peng ◽  
H. Y. Li ◽  
D. F. Lim ◽  
S. Gao ◽  
C. S. Tan
Keyword(s):  
Thermal Reliability ◽  
Self Assembled Monolayer ◽  
Fine Pitch ◽  
Self Assembled ◽  
Cu Bonding ◽  
3D Stacking

Characterisation of Cu/Cu bonding using self-assembled monolayer

2018 ◽  
Vol 30 (2) ◽  
pp. 106-111 ◽  
Author(s):  
Maria Lykova ◽  
Iuliana Panchenko ◽  
Ulrich Künzelmann ◽  
Johanna Reif ◽  
Marion Geidel ◽  
...  
Keyword(s):  
Shear Strength ◽  
Sulphuric Acid ◽  
Self Assembled Monolayer ◽  
Bonding Quality ◽  
Content Type ◽  
Cu Interconnects ◽  
First Case ◽  
Strength Tests ◽  
Self Assembled ◽  
Cu Bonding

Purpose Cu/Cu diffusion bonding is characterised by high electrical and thermal conductivity, as well as the mechanical strength of the interconnects. But despite a number of advantages, Cu oxidises readily upon exposure to air. To break through the adsorbed oxide-layer high temperature and pressure, long bonding time and inert gas atmosphere are required during the bonding process. This paper aims to present the implementation of an organic self-assembled monolayer (SAM) as a temporary protective coating that inhibits Cu oxidation. Design/methodology/approach Information concerning elemental composition of the Cu surface has been yielded by X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared (FTIR) spectroscopy. Two types of substrates (electroplated and sputtered Cu) are prepared for thermocompression bonding in two different ways. In the first case, Cu is cleaned with dilute sulphuric acid to remove native copper oxide. In the second case, passivation with SAM followed the cleaning step with dilute sulphuric acid. Shear strength, fracture surface, microstructure of the received Cu/Cu interconnects are investigated after the bonding procedure. Findings The XPS method revealed that SAM can retard Cu from oxidation on air for at least 12 h. SAM passivation on the substrates with sputtered Cu appears to have better quality than on the electroplated ones. This derives from the results of the shear strength tests and scanning electron microscopy (SEM) imaging of Cu/Cu interconnects cross sections. SAM passivation improved the bonding quality of the interconnects with sputtered Cu in comparison to the cleaned samples without passivation. Originality/value The Cu/Cu bonding procedure was optimised by a novel preparation method using SAMs which enables storage and bonding of Si-dies with Cu microbumps at air conditions while remaining a good-quality interconnect. The passivation revealed to be advantageous for the smooth surfaces. SEM and shear strength tests showed improved bonding quality for the passivated bottom dies with sputtered Cu in comparison to the samples without SAM.

Self-Assembled Fluid Phase Floating Membranes with Tuneable Water Interlayers

2019 ◽  
Author(s):  
Luke Clifton ◽  
Nicoló Paracini ◽  
Arwel V. Hughes ◽  
Jeremy H. Lakey ◽  
Nina-Juliane Seinke ◽  
...  
Keyword(s):  
Fluid Phase ◽  
Interlayer Thickness ◽  
Supported Bilayers ◽  
Self Assembled Monolayer ◽  
High Coverage ◽  
Nano Technology ◽  
Surface Distance ◽  
Potential Applications ◽  
Self Assembled ◽  
Coated Surfaces

<p>We present a reliable method for the fabrication of fluid phase unsaturated bilayers which are readily self-assembled on charged self-assembled monolayer (SAM) surfaces producing high coverage floating supported bilayers where the membrane to surface distance could be controlled with nanometer precision. Vesicle fusion was used to deposit the bilayers onto anionic SAM coated surfaces. Upon assembly the bilayer to SAM solution interlayer thickness was 7-10 Å with evidence suggesting that this layer was present due to SAM hydration repulsion of the bilayer from the surface. This distance could be increased using low concentrations of salts which caused the interlayer thickness to enlarge to ~33 Å. Reducing the salt concentration resulted in a return to a shorter bilayer to surface distance. These accessible and controllable membrane models are well suited to a range of potential applications in biophysical studies, bio-sensors and Nano-technology.</p><br>

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