scholarly journals Effect of Combined Hydrophilic Activation on Interface Characteristics of Si/Si Wafer Direct Bonding

Processes ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1599
Author(s):  
Dongling Li ◽  
Xiaohan Cui ◽  
Mao Du ◽  
Ying Zhou ◽  
Fenfen Lan

Wafer direct bonding is an attractive approach to manufacture future micro-electro-mechanical system (MEMS) and microelectronic and optoelectronic devices. In this paper, a combined hydrophilic activated Si/Si wafer direct bonding process based on wet chemical activation and O2 plasma activation is explored. Additionally, the effect on bonding interface characteristics is comprehensively investigated. The mechanism is proposed to better understand the nature of hydrophilic bonding. The water molecule management is controlled by O2 plasma activation process. According to the contact angle measurement and FTIR spectrum analysis, it can be concluded that water molecules play an important role in the type and density of chemical bonds at the bonding interface, which influence both bonding strength and voids’ characteristics. When annealed at 350 °C, a high bonding strength of more than 18.58 MPa is obtained by tensile pulling test. Cross sectional SEM and TEM images show a defect-free and tightly bonded interface with an amorphous SiOx layer of 3.58 nm. This amorphous SiOx layer will induce an additional energy state, resulting in a lager resistance. These results can facilitate a better understanding of low-temperature hydrophilicity wafer direct bonding and provide possible guidance for achieving good performance of homogenous and heterogenous wafer direct bonding.

Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1575
Author(s):  
Wenting Zhang ◽  
Caorui Zhang ◽  
Junmin Wu ◽  
Fei Yang ◽  
Yunlai An ◽  
...  

SiC direct bonding using O2 plasma activation is investigated in this work. SiC substrate and n− SiC epitaxy growth layer are activated with an optimized duration of 60s and power of the oxygen ion beam source at 20 W. After O2 plasma activation, both the SiC substrate and n− SiC epitaxy growth layer present a sufficient hydrophilic surface for bonding. The two 4-inch wafers are prebonded at room temperature followed by an annealing process in an atmospheric N2 ambient for 3 h at 300 °C. The scanning results obtained by C-mode scanning acoustic microscopy (C-SAM) shows a high bonding uniformity. The bonding strength of 1473 mJ/m2 is achieved. The bonding mechanisms are investigated through interface analysis by transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDX). Oxygen is found between the two interfaces, which indicates Si–O and C–O are formed at the bonding interface. However, a C-rich area is also detected at the bonding interface, which reveals the formation of C-C bonds in the activated SiC surface layer. These results show the potential of low cost and efficient surface activation method for SiC direct bonding for ultrahigh-voltage devices applications.


Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2951
Author(s):  
Mirosław Kwiatkowski ◽  
Jarosław Serafin ◽  
Andy M. Booth ◽  
Beata Michalkiewicz

This paper presents the results of a computer analysis of the effect of activation process temperature on the development of the microporous structure of activated carbon derived from the leaves of common polypody (Polypodium vulgare) via chemical activation with phosphoric acid (H3PO4) at activation temperatures of 700, 800, and 900 °C. An unconventional approach to porous structure analysis, using the new numerical clustering-based adsorption analysis (LBET) method together with the implemented unique gas state equation, was used in this study. The LBET method is based on unique mathematical models that take into account, in addition to surface heterogeneity, the possibility of molecule clusters branching and the geometric and energy limitations of adsorbate cluster formation. It enabled us to determine a set of parameters comprehensively and reliably describing the porous structure of carbon material on the basis of the determined adsorption isotherm. Porous structure analyses using the LBET method were based on nitrogen (N2), carbon dioxide (CO2), and methane (CH4) adsorption isotherms determined for individual activated carbon. The analyses carried out showed the highest CO2 adsorption capacity for activated carbon obtained was at an activation temperature of 900 °C, a value only slightly higher than that obtained for activated carbon prepared at 700 °C, but the values of geometrical parameters determined for these activated carbons showed significant differences. The results of the analyses obtained with the LBET method were also compared with the results of iodine number analysis and the results obtained with the Brunauer–Emmett–Teller (BET), Dubinin–Radushkevich (DR), and quenched solid density functional theory (QSDFT) methods, demonstrating their complementarity.


Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 237 ◽  
Author(s):  
Yanni Wei ◽  
Hui Li ◽  
Fu Sun ◽  
Juntao Zou

The Cu/Al composites conductive head is widely used in hydrometallurgy as the core component of cathode plate. Its conductive properties directly affect the power consumption, and the bonding strength and corrosion resistance determine the conductive head service life. The Cu/Al conductive head prepared by explosion welding, cold pressure welding, and solid-liquid casting methods were investigated in this paper. The interface microstructure and compositions were examined by scanning electron microscope and X-ray energy dispersive spectrometry. The bonding strength, interface conductivity, and the corrosion resistance of three types of joints were characterized. The Cu/Al bonding interface produced by explosive welding presented a wavy-like morphology with typical defects and many of brittle compounds. A micro-interlocking effect was caused by the sawtooth structures on the cold pressure welding interface, and there was no typical metallurgical reaction on the interface. The Cu/Al bonding interface prepared by solid-liquid casting consisted mainly of an Al-Cu eutectic microstructure (Al2Cu+Al) and partial white slag inclusion. The thickness of the interface transition layer was about 200–250 µm, with defects such as holes, cracks, and unwelded areas. The conductivity, interfacial bonding strength, and corrosion resistance of the conductive head prepared by explosive welding were superior to the other two.


2019 ◽  
Vol 19 (2) ◽  
pp. 155-161 ◽  
Author(s):  
Kwan Hong Min ◽  
Sungjin Choi ◽  
Myeong Sang Jeong ◽  
Min Gu Kang ◽  
Sungeun Park ◽  
...  

Author(s):  
Nawwarah Mokti ◽  
Azry Borhan ◽  
Siti Nur Azella Zaine ◽  
Hayyiratul Fatimah Mohd Zaid

The use of an activating agent in chemical activation of activated carbon (AC) production is very important as it will help to open the pore structure of AC as adsorbents and could enhance its performance for adsorption capacity. In this study, a pyridinium-based ionic liquid (IL), 1-butylpyridinium bis(trifluoromethylsulfonyl) imide, [C4Py][Tf2N] has been synthesized by using anion exchange reaction and was characterized using few analyses such as 1H-NMR, 13C-NMR and FTIR. Low-cost AC was synthesized by chemical activation process in which rubber seed shell (RSS) and ionic liquid [C4Py][Tf2N] were employed as the precursor and activating agent, respectively. AC has been prepared with different IL concentration (1% and 10%) at 500°C and 800°C for 2 hours. Sample AC2 shows the highest SBET and VT which are 392.8927 m2/g and 0.2059 cm3/g respectively. The surface morphology of synthesized AC can be clearly seen through FESEM analysis. A high concentration of IL in sample AC10 contributed to blockage of pores by the IL. On the other hand, the performance of synthesized AC for CO2 adsorption capacity also studied by using static volumetric technique at 1 bar and 25°C. Sample AC2 contributed the highest CO2 uptakes which is 50.783 cm3/g. This current work shows that the use of low concentration IL as an activating agent has the potential to produce porous AC, which offers low-cost, green technology as well as promising application towards CO2 capture.


2020 ◽  
Vol 107 ◽  
pp. 113589 ◽  
Author(s):  
Toshiyuki Tabata ◽  
Loic Sanchez ◽  
Vincent Larrey ◽  
Frank Fournel ◽  
Hubert Moriceau

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1377 ◽  
Author(s):  
Ruoke Ma ◽  
Xianxian Qin ◽  
Zhigao Liu ◽  
Yunlin Fu

Activated carbon fiber was prepared from liquefied wood by chemical activation with ZnCl2 (Z-LWACF) at different impregnation ratios, with a particular focus on its adsorption property, kinetic and isotherm. The characterization and properties of Z-LWACFs were investigated by nitrogen adsorption/desorption, X-ray photoelectron spectroscopy (XPS), methylene blue (MB) and iodine adsorption. Two activation process methods were employed to prepare Z-LWACF and contrasted with others fibers. The results showed that the Z-LWACF obtained by one-step ZnCl2 activation present higher yields and specific surface area than others fibers. Besides, the change of MB adsorption value at different impregnation ratios was consistent with pore structure distribution above 1.5 nm pore size, indicating that larger micropores (1.5 to 2 nm) and mesopores played a major role in the MB adsorption by Z-LWACF. The kinetics of MB adsorption process was found to follow the pseudo-second-order kinetic model and the adsorption rate was controlled by chemisorption. It was also found that MB adsroption by Z-LWACF belonged to monolayer adsorption and Z-LWACF was easy to adsorb MB.


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