Ambient Copper-Copper Thermocompression Bonding using Self Assembled Monolayers

2008 ◽  
Vol 1112 ◽  
Author(s):  
Xiaofang Ang ◽  
Jun Wei ◽  
Zhong Chen ◽  
Chee Cheong Wong
Keyword(s):  
Bonding Temperature ◽  
Three Dimensional ◽  
Copper Surface ◽  
Physical Contact ◽  
Ambient Conditions ◽  
Thermal Dependence ◽  
Self Assembled Monolayer ◽  
Assembled Monolayers ◽  
Thermocompression Bonding ◽  
Self Assembled

AbstractA typical copper-copper thermocompression bonding process is carried out in an ultrahigh vacuum (UHV) or inert environment at a bonding temperature >300°C. The ultraclean environment serves a single purpose – to maintain oxide-free copper surfaces, allowing intimate physical contact between copper atoms. This study investigates the temperature dependence of direct copper bonding from room temperature to 300°C under ambient condition. An anomalous thermal dependence of bond strength occurs between 80°C to 140°C where an increase in bonding temperature within this regime is in fact, detrimental to joint strength. This is interpreted as a thermal competition between oxidation and bond formation. This study also demonstrates that by simply coating the copper surface with a self assembled monolayer of 1-undecanethiol prior to bonding, Cu joints can be successfully formed at close to ambient temperature without a vacuum, yielding joint shear strengths on the order of 70MPa. The densely packed monolayer serves to passivate the copper surface against oxidation under ambient conditions. The ultrathin organic monolayer structure, as compared to a bulk oxide layer, could be easily displaced during the mechanical deformation at the bonding interface which accompanies thermocompression. This method could be an effective simple bonding solution for three-dimensional integrated chips.

Low Temperature Direct Metal Bonding by Self Assembled Monolayers

2007 ◽  
Vol 990 ◽  
Author(s):  
Xiaofang Ang ◽  
Li Cheong Chin ◽  
Guo Ge Zhang ◽  
Jun Wei ◽  
Zhong Chen ◽  
...  
Keyword(s):  
Low Temperature ◽  
Photoelectron Spectroscopy ◽  
Self Assembly ◽  
Surface Passivation ◽  
Bonding Temperature ◽  
Gold Surface ◽  
Self Assembled Monolayers ◽  
Assembled Monolayers ◽  
Thermocompression Bonding ◽  
Self Assembled

ABSTRACTElevated bonding temperature for interconnection deteriorates the reliability of both the device and the interconnect; hence the imperative for developing low temperature bonding methods. This study investigates the feasibility of using self-assembled monolayers (SAMs) to assist direct gold-gold bonding. This involves a simple molecular self-assembly process whereby a monolayer of alkyl chains with a sulfur end group is attached to the gold surface prior to thermocompression bonding. Using this method, we have achieved gold to gold bonding at a bonding temperature below 100°C, a significant reduction compared to the conventional bonding temperatures of above 150 °C. We attribute this temperature reduction to two properties of SAMs - (1) surface passivation of the Au surface that precludes adsorption of surface contaminants, and (2) The easy displacement of SAMs through thermal desorption just before bonding occurs. This SAMs-assisted bonding mechanism is supported by X-ray photoelectron spectroscopy (XPS) and surface plasmon resonance (SPR) results.

scholarly journals Inhibition Effect of Three-Dimensional (3D) Nanostructures on the Corrosion Resistance of 1-Dodecanethiol Self-Assembled Monolayer on Copper in NaCl Solution

Materials ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1225 ◽  
Author(s):  
Shuai Hu ◽  
Zhenyu Chen ◽  
Xingpeng Guo
Keyword(s):  
Corrosion Resistance ◽  
Three Dimensional ◽  
Copper Surface ◽  
Nacl Solution ◽  
Self Assembled Monolayer ◽  
Simple Method ◽  
Self Assembled ◽  
Bare Copper ◽  
3D Nanostructure ◽  
Anticorrosion Properties

A novel and simple method to improve the corrosion resistance of copper by constructing a three-dimensional (3D) 1-dodecanethiol self-assembled monolayer (SAM) in 3.5% NaCl solution is reported in this study. Several drops of 1% H3PO4 solution are thinly and uniformly distributed on copper surface to form a 3D nanostructure constituted by Cu3(PO4)2 nanoflowers. The anticorrosion properties of 1-dodecanethiol SAM on copper surface and on copper surface that is treated with H3PO4 solution were evaluated. Results demonstrated that 1-dodecanethiol SAM on bare copper surface exhibits good protection capacity, whereas a copper surface that is pretreated with H3PO4 solution can substantially enhance the corrosion resistance of 1-dodecanethiol SAM.

Copper to Copper Direct Bonding Assisted by Self-Assembled Monolayer

2010 ◽  
Author(s):  
D. F. Lim ◽  
X. F. Ang ◽  
J. Wei ◽  
C. M. Ng ◽  
C. S. Tan
Keyword(s):  
Contact Angle ◽  
Water Contact Angle ◽  
Bonding Temperature ◽  
Contact Angle Measurement ◽  
Copper Surface ◽  
Angle Measurement ◽  
Self Assembled Monolayer ◽  
Water Contact ◽  
Water Contact Angle Measurement ◽  
Self Assembled

In this article, a self-assembled monolayer (SAM) is applied onto the copper surface in an attempt to lower the required bonding temperature. Alkane-thiol with 6-carbon chain length is used and tested for bonding experiment. The adsorption of SAM is confirmed by the sharp rise of the water contact angle measurement and the reduced in the surface roughness. Next, the desorption of SAM is done at a high temperature anneal (<300°C) in an inert ambient and its properties are characterized by the water contact angle measurement and XPS. It is found that the water contact angle measurement decreases sharply close back to the contact angle of the pure blanket copper surface after annealing of SAM. The XPS results also show the ability of SAM in protecting Copper surface from oxidation. Finally, shear test is performed on Cu-Cu structures bonded at low temperature (250°C) in order to verify the SAM behavior in protecting the copper surface from oxidation and enhancement for bonding. The wafer pairs with and without SAM are intentionally exposed in clean room environment for few days. The bonded pieces are diced and subject to shear stress and results show that with SAM protection, shear strength is improved due to the enhancement in grain growth as a result of cleaner surface.

Copper Protection by SAM and Low Temperature Bonding for 3Dimentional Integration

2013 ◽  
Vol 716 ◽  
pp. 223-227
Author(s):  
Tamal Ghosh ◽  
Ashudeb Dutta ◽  
Shivgovind Singh
Keyword(s):  
Thermal Desorption ◽  
Bonding Temperature ◽  
Pure Copper ◽  
Research Work ◽  
Surface Oxidation ◽  
Copper Surface ◽  
Self Assembled Monolayer ◽  
Surface Protection ◽  
Thermocompression Bonding ◽  
Low Temperature Bonding

3Dimensional Integration can solve many challenges which are being faced by modern planer integration. The major bottleneck of 3D-Integration are contamination and Copper surface oxidation which is the cause of the requirement of high temperature while bonding. Reduction of this high bonding temperature is the key challenge of 3Dimensional Integration. In this research work we investigate and compare the Copper surface protection characteristic of Self-Assembled Monolayer (SAM) of Alkyl Thiol having different Carbon chains (C6,Hexanethiol and C12, Dodecanethiol). We also study the thermal desorption of these SAM layers. SAM can minimize the oxidation of the Copper which acts as a bonding medium. By thermal desorption the pure Copper surface is brought back and exposed. Finally Copper-Copper thermocompression bonding is performed in different conditions and compared.

Laser Polishing of Cold Work Steel AISI D2 for Dry Metal Forming Tools: Surface Homogenization, Refinement and Preparation for Self-Assembled Monolayers

2018 ◽  
Vol 767 ◽  
pp. 69-76 ◽  
Author(s):  
Ingo Ross ◽  
André Temmler ◽  
Moritz Küpper ◽  
Stephan Prünte ◽  
Marco Teller ◽  
...  
Keyword(s):  
Cold Extrusion ◽  
Self Assembled Monolayers ◽  
Homogeneous Distribution ◽  
Self Assembled Monolayer ◽  
Pulsed Laser Radiation ◽  
Laser Polishing ◽  
Assembled Monolayers ◽  
Aisi D2 ◽  
Self Assembled ◽  
Forming Tools

Liquid lubrication guarantees high precision and surface quality of workpieces in industrial forming processes. In the case of aluminum cold extrusion, wear and cold welding due to direct contact of tool and workpiece are usually prevented by the extensive use of lubricants. Since the use of lubricants is economically and ecologically unfavorable, surface treatments of tools by, e.g. laser polishing and/or coatings are in the focus of current investigations to substitute these lubricants and establish so called “dry metal forming” processes. The material AISI D2, a ledeburitic 12% chromium steel which is known to have a significant amount of chromium carbide precipitations, is widely used in cold extrusion for forming tools. The large fraction of chromium carbide precipitations, however, hinder the formation of a dense self-assembled monolayer (SAM) that is necessary to avoid direct contact of reactive aluminum with surface oxides of the tool. Therefore, a homogeneous distribution of the chemical elements with a smaller fraction or no chromium carbides in the steel matrix, particularly in the tool surface, is aimed for. Using laser polishing, the surface layer is molten by continuous or pulsed laser radiation. Within the melt pool, the elementary distribution is homogenized as a result of thermal convection and diffusion processes, as well as a smoothed surface and a grain refinement are achieved. Consequently, the effects of the surface treatment by laser polishing on the area coverage of self-assembled monolayers are investigated. Thus, a combined surface treatment by laser polishing and functionalization with a dense self-assembled monolayer shall reduce overall adhesive wear. For this investigation, several specimens of conventional manufactured and powder metallurgical molten AISI D2 are laser polished using continuous or pulsed laser radiation or a combination of both. The resulting surfaces are investigated by microscopy and spectroscopic techniques to analyze the surface topography and the elemental distribution near to the surface. These results are compared to those of conventionally hand-polished specimens. Furthermore, the influence of the element homogenization and grain refinement on the area coverage of self-assembled monolayers is explored. First results show that laser polishing of AISI D2 is suitable to achieve a reduction of grain size and a more homogeneous distribution of chromium carbides within the surface layer.

Spectral and cyclic voltammetric characterization of self-assembled monolayers on gold of pyrene end-labeled oligonucleotide duplexes

1999 ◽  
Vol 77 (5-6) ◽  
pp. 1077-1084 ◽  
Author(s):  
R Scott Reese ◽  
Marye Anne Fox
Keyword(s):  
Gold Surface ◽  
Self Assembled Monolayers ◽  
Self Assembled Monolayer ◽  
Surface Emission ◽  
Assembled Monolayers ◽  
Oligonucleotide Duplex ◽  
Self Assembled ◽  
Duplex Formation

Self-assembled monolayers of sulfur-terminated oligonucleotide duplexes were formed on flat gold surfaces, either by exposure of a self-assembled monolayer bearing one oligonucleotide strand to the complementary strand or by preformation of a oligonucleotide duplex that was then deposited on a fresh gold surface. Virtually identical spectral behavior was observed whether the duplex was produced before deposition or by in situ complementary association. With a duplex bearing an appropriate pyrene end-label, the resulting thin film was photoresponsive. Surface emission measurements show no evidence for pyrene aggregation on the modified surfaces. The polarity of the photocurrent, reflecting photoinduced electron transfer initiated by photoexcitation of pyrene, is opposite that expected from the oligonucleotide-mediated reduction of the appended pyrene excited state.Key words: oligonucleotide, self-assembled monolayer, duplex formation, photoelectrochemistry, surface emission.

Self-Assembled Monolayers of 12-Mercaptododecylphosphonic Acid on Titania Particles; Application to the Extraction of Heavy Metals

2004 ◽  
Vol 847 ◽  
Author(s):  
Sébastien Anthérieu ◽  
Florence Brodard-Séverac ◽  
Gilles Guerrero ◽  
P. Hubert Mutin
Keyword(s):  
Heavy Metals ◽  
Chemical Analysis ◽  
Phosphonic Acid ◽  
Metal Extraction ◽  
Self Assembled Monolayers ◽  
Extraction Ability ◽  
Self Assembled Monolayer ◽  
Inorganic Hybrid ◽  
Assembled Monolayers ◽  
Self Assembled

ABSTRACTTitania particles (P25 DEGUSSA AG) were treated by a solution of 12-mercaptododecyl-phosphonic acid (MDPA) in toluene to obtain an organic-inorganic hybrid material with thiol functions at the surface. This material was characterized by chemical analysis, solid state 31P MAS NMR and FTIR spectroscopies, and XPS. Reaction of the phosphonic acid end of MDPA with the TiO2 surface led to the formation of a relatively dense and well-ordered self-assembled monolayer (SAM), with a density of about 3.9 SH functions per nm2. This material was tested for the extraction of mercury in water at pH 7, 9, and 11. Chemical analysis indicated no loss of SH functionality, even at pH 11. The best extraction results were obtained at pH 9 and 11, with a metal extraction ability between 85 and 90%.

Contact Angle Variation on a Copper Surface Treated With Self-Assembled Monolayer (SAM) of N-octadecyl Mercaptan

2011 ◽  
Vol 133 (8) ◽  
Author(s):  
Yulong Ji ◽  
Hsiu-hung Chen ◽  
Qingsong Yu ◽  
Xuehu Ma ◽  
H. B. Ma
Keyword(s):  
Contact Angle ◽  
Copper Surface ◽  
Self Assembled Monolayer ◽  
Angle Variation ◽  
Self Assembled
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