- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Probing Self-associated Intermolecular H-bonding using low-frequency SERS coupled with mid-IR SERS and DFT Study: A case study of 2-MBA adsorbed on ZnO nanoparticles
摘要： In the present study, low-frequency SERS is reported for the first time to investigate the intermolecular interaction. The low-frequency SERS in THz region (>50 cm-1) and the mid-IR region is used to probe the H-bonding interaction in 2-mercaptobenzoic acid (2-MBA) molecules adsorbed on the surface of ZnO nanoparticles. The self-association due to H-bonding leads to dimer formation of 2-MBA through carboxylic acid groups. The characteristics Raman bands of 2-MBA dimer; H-bonded O-H stretching and out-of-plane O-H bending modes are observed. Subsequently, this dimer formation causes the evolution of two new low-frequency modes at 90 cm-1 (shear dimer in-plane bending) and 110 cm-1 (shear dimer stretching) of intermolecular H-bonding and blue-shift of the torsional mode of (–COOH) + (–SH). In the THz region (50-200 cm-1), vibrational modes are blue-shifted while in the mid-IR region, symmetric out-of-plane O-H bending is red-shifted. The present work shows that SERS can be used to study intermolecular H-bonding of molecules at very low concentration.
关键词： Intermolecular interaction,Low-frequency,SERS,H-bonding
更新于2025-09-11 14:15:04
-
Development and optimization of the laser-assisted bonding process for a flip chip package
摘要： In a ?ne pitch ?ip chip package, a laser-assisted bonding (LAB) technology has recently been developed to overcome several reliability and throughput issues in the conventional mass re?ow (MR) and thermal compression bonding technology. This study investigated the LAB process for a ?ip chip package with a copper (Cu) pillar bump using numerical heat transfer and thermo-mechanical analysis. During the LAB process, the temperature of the silicon die was uniform across the entire surface and increased to 280 (cid:3)C within a few seconds; this was high enough to melt the solder. The heat in the die was quickly conducted to the substrate through the Cu pillar bumps. Meanwhile, the substrate temperature was low and remained constant. Therefore, a stable solder interconnection was quickly achieved with minimal stress and thermal damage to the package. The substrate thickness, the number of Cu bumps, and the bonding stage temperature were found to be important factors affecting the heat transfer behavior of the package. The temperature of the die decreased when a thinner substrate, a higher number of Cu bumps, and a lower bonding stage temperature were used. If the temperature of the die was not suf?ciently high, insuf?cient heat was transferred to the solder to melt it, resulting in incomplete solder joint formation. Thermo-mechanical analysis also showed that the LAB process produced lower warpage and thermo-mechanical strain than the conventional MR process. These results indicated that a LAB process using a selective local heating method would be bene?cial in reducing thermo-mechanical stress and increasing throughput for the ?ne pitch ?ip chip packages.
关键词： Laser-assisted bonding,Copper pillar bump,Thermo-mechanical analysis,Flip chip package,Heat transfer
更新于2025-09-11 14:15:04
-
[IEEE 2019 IEEE 16th International Conference on Group IV Photonics (GFP) - Singapore, Singapore (2019.8.28-2019.8.30)] 2019 IEEE 16th International Conference on Group IV Photonics (GFP) - Dark Current Analysis of Vertical p-i-n Photodetectors on a Germanium-on-Insulator Platform
摘要： Dark current of vertical p-i-n photodetectors on a germanium-on-insulator platform was analyzed. The activation energy was found to be from 0.15 to 0.36 eV under reserve bias. The dark current generation was interpreted by Shockley-Read-Hall and trap-assisted-tunneling effects. This work provides the interpretation on germanium-on-insulator photodetectors and suggests the alternative to suppress the dark current generation for Si-based Ge photodetectors.
关键词： Ge-on-insulator,photodetector,activation energy,direct wafer bonding
更新于2025-09-11 14:15:04
-
Enhancement of molecular-level ordering of isoindigo based organic materials through deprotecting of cleavable carbamate groups with long alkyl chains
摘要： A new highly soluble isoindigo based organic material with both cleavable carbamate protecting groups bearing long alkyl chains and thiophene groups was successfully synthesized. The carbamate protecting groups were easily removed by solvent-vapor thermal annealing using a mixture of trifluoroacetic acid and chloroform. Deprotection of the NH functional groups in the isoindigo backbone in situ facilitated H-bonding that dramatically improved the strength of the intermolecular interactions. X-ray diffraction and high-voltage electron microscopy studies of the resulting organic material showed long-range ordered crystalline structure. High crystallinity due to enhanced π-π stacking and hydrogen bonding significantly improved the charge carrier mobility. The hole mobilities of isoindigo based organic material measured by SCLC method improved from 3.46 x 10^-6 cm^2 V^-1 s^-1 to 1.13 x 10^-3 cm^2 V^-1 s^-1 upon deprotection of the NH functional groups.
关键词： Isoindigo,Conjugated,Crystallinity,Hydrogen bonding,Protecting groups
更新于2025-09-11 14:15:04
-
Vacuum-UV of polyetheretherketone (PEEK) as a surface pre-treatment for structural adhesive bonding
摘要： Polyetheretherketone (PEEK) is known for its poor wettability and poor adhesive properties. Hence, for the creation of reliable high-strength structural adhesive bonded joints, surface treatment of PEEK is required. In this work high strength bondable PEEK surfaces were achieved through a vacuum-UV (VUV) treatment. Samples of amorphous and semi-crystalline PEEK films were exposed to different VUV radiation doses. Additionally oxygen low-pressure plasma (LPP) and untreated (as received) PEEK samples were investigated for comparison. Surfaces were characterized using x-ray photoelectron spectroscopy (XPS), contact angle measurements (CA), atomic force microscopy (AFM) and confocal laser scanning microscopy (CLSM). Tensile tests of the PEEK films were carried out, to investigate changes in the mechanical properties in the bulk of the PEEK films due to the VUV exposure. The adhesive bond strength of treated specimen was determined through two different test methods (tensile and shear). These strengths were compared to the created surface properties. A strong correlation between the contact angle and the creation of functional groups was observed. VUV radiation appears as a suitable pre-treatment method for PEEK, as adhesive bonds of high strength were achieved after 5 seconds. Additionally, the usage of a VUV excimer lamp is simple, cheap and easy for automation.
关键词： X-ray photoelectron spectroscopy,Vacuum-UV (VUV),contact angles,chemical surface functionalization,structural adhesive bonding,Polyetheretherketone (PEEK),atomic force microscopy
更新于2025-09-11 14:12:44
-
Room-Temperature Bonding of Wafers with Smooth Au Thin Films in Ambient Air Using a Surface-Activated Bonding Method
摘要： Wafers with smooth Au thin ?lms (rms surface roughness: < 0.5 nm, thickness: < 50 nm) were successfully bonded in ambient air at room temperature after an Ar radio frequency plasma activation process. The room temperature bonded glass wafers without any heat treatment showed a su?ciently high die-shear strength of 47–70 MPa. Transmission electron microscopy observations showed that direct bonding on the atomic scale was achieved. This surface-activated bonding method is expected to be a useful technique for future heterogeneous photonic integration.
关键词： Au-Au bonding,surface-activated bonding,room-temperature bonding,heterogeneous integration
更新于2025-09-10 09:29:36
-
Stability of diamond/Si bonding interface during device fabrication process
摘要： Diamond/Si bonding interface with an entire contact area and high thermal stability is achieved by surface activated bonding method. The fabrication of diamond field-effect transistors (FETs) on the diamond bonded to Si is demonstrated. The FET exhibits clear saturation and pinch-off characteristics. A 5 nm thick SixCx-1 layer was formed at the interface with annealing at 1000 °C. The layer was formed by the inter-diffusion of carbon and Si atoms near the bonding interface, which plays a role of residual stress relaxation between diamond and Si. These results suggest that diamond/Si heterostructures are applicable for combining diamond devices with Si LSI.
关键词： surface activated bonding,diamond/Si bonding,heterostructures,thermal stability,field-effect transistors
更新于2025-09-10 09:29:36
-
Bonding-Based Wafer-Level Vacuum Packaging Using Atomic Hydrogen Pre-Treated Cu Bonding Frames
摘要： A novel surface activation technology for Cu-Cu bonding-based wafer-level vacuum packaging using hot-wire-generated atomic hydrogen treatment was developed. Vacuum sealing temperature at 300 ?C was achieved by atomic hydrogen pre-treatment for Cu native oxide reduction, while 350 ?C was needed by the conventional wet chemical oxide reduction procedure. A remote-type hot-wire tool was employed to minimize substrate overheating by thermal emission from the hot-wire. The maximum substrate temperature during the pre-treatment is lower than the temperature of Cu nano-grain re-crystallization, which enhances Cu atomic diffusion during the bonding process. Even after 24 h wafer storage in atmospheric conditions after atomic hydrogen irradiation, low-temperature vacuum sealing was achieved because surface hydrogen species grown by the atomic hydrogen treatment suppressed re-oxidation. Vacuum sealing yield, pressure in the sealed cavity and bonding shear strength by atomic hydrogen pre-treated Cu-Cu bonding are 90%, 5 kPa and 100 MPa, respectively, which are equivalent to conventional Cu-Cu bonding at higher temperature. Leak rate of the bonded device is less than 10?14 Pa m3 s?1 order, which is applicable for practical use. The developed technology can contribute to low-temperature hermetic packaging.
关键词： Cu thermos-compression bonding,atomic hydrogen,wafer-level vacuum packaging,nano-grain,wafer bonding,hot wire
更新于2025-09-10 09:29:36
-
[Methods in Molecular Biology] Microfluidic Electrophoresis Volume 1906 (Methods and Protocols) || Fabrication of Glass Microfluidic Devices
摘要： This chapter provides step-by-step procedures for the fabrication of glass-based micro?uidic devices. These procedures include device design, photomask generation, photolithography, channel etching, and high-temperature bonding.
关键词： Glass bonding,Micro?uidics,Photolithography,Etching,Channel manifold
更新于2025-09-10 09:29:36
-
Solubility and H-bonding of poly(vinylidene fluoride) copolymers in carbonyl liquids: Experiment and molecular simulation
摘要： H-bond formation among fluoropolymers and carbonyl solvents was studied by microcalorimetry and quantum chemistry simulation. Typically, fluorine atoms in organic molecules depress their ability to molecular interactions with solvents. Meanwhile, it is not the case if fluoropolymer is dissolved in carbonyl solvent. Among other organic solvents carbonyl-containing liquids are characterized by very large exothermic effects of dissolution of vinylidene fluoride copolymers which are typical for the systems with electron-donor-acceptor complexes. The enthalpy of mixing in the entire concentration range was determined for P(VDF-co-HFP) and P(VDF-co-CTFE) solutions in ethyl acetate and Flory-Huggins parameter was evaluated. It was ?1.31, which means very strong interaction among solvent and vinylidene fluoride monomer units. This interaction was modeled by quantum chemistry semi-empirical AM1, PM3, PM5 and density functional B88-PW91, B88-LYP, D-VWN calculations for the complexes between acetone or ethyl acetate and vinylidene fluoride tetramer. The heat of formation of the complex from its components was found around ?18 kJ/mol. The binding site of the complex was a macrocyclic structure which comprised H-bonds between carbonyl and methylene hydrogens of vinylidene fluoride backbone, and weaker H-bonds between fluorine atoms and methyl hydrogen. The analysis of molecular orbitals of the complex reveals extended electron delocalization across the binding center.
关键词： Calorimetry,H-bonding,Computer modeling,Solubility of vinylidene fluoride copolymers
更新于2025-09-10 09:29:36