• Journal of the Microelectronics and Packaging Society
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• v.28 no.2
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• pp.89-94
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• 2021

The mechanical reliability of flexible devices has become a major concern on their commercialization, where the importance of reliable bonding is highlighted. In terms of component materials' properties, it is important to consider thermal damage of polymer substrates that occupy large area of the flexible device. Therefore, room temperature bonding process is highly advantageous for implementing flexible device assemblies with mechanical reliability. Conventional epoxy resins for the bonding still require curing at high temperatures. Even after the curing procedure, the bonding joint loses flexibility and exhibits poor fatigue durability. To solve this problems, low-temperature and adhesive-free bonding are required. In this work, we develop a room temperature bonding process for polymer substrates using carbon nanotube heated by microwave irradiations. After depositing multiple-wall carbon nanotubes (MWNTs) on PET polymer substrates, they are heated locally with by microwave while the entire bonding specimen maintains room temperature and the heating induces mechanical entanglement of CNT-PET. The room temperature bonding was conducted for a PET/CNT/PET specimen at 600 watt of microwave power for 10 seconds. Thickness of the CNT bonding joint was very thin that it obtains flexibility as well. In order to evaluate the mechanical reliability of the joint specimen, we performed lap shear test, three-point bending test, and dynamic bending test, and confirmed excellent joint strength, flexibility, and bending durability from each test.

• Transactions of Materials Processing
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• v.13 no.7
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• pp.623-628
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• 2004

This paper is concerned with pressure welding, which has been known as a main bonding mechanism during the cold and warm forming such as clad extrusion or bundle extrusion/drawing. Bonding characteristics between the Cu and Al plates by pressure welding are investigated focusing on the weak bonding. Experiments are performed at the cold and warm temperatures ranging from the room temperature to $200^{\circ}C$. The important factors examined in this work are the welding pressure, pressure holding time, surface roughness, and temperature. A bonding map, which can identify the bonding criterion with a weak bonding strength of IMPa , is proposed in terms of welding pressure and surface roughness fur the cold and warm temperature ranges.

• Applied Science and Convergence Technology
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• v.26 no.3
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• pp.43-46
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• 2017

Aluminum-doped ZnO (AZO) thin films were deposited by atomic layer deposition (ALD) with respect to the Al doping concentrations. In order to explain the chemical stability and electrical properties of the AZO thin films after hydrogen peroxide ($H_2O_2$) solution immersion treatment at room temperature, we investigated correlations between the electrical resistivity and the electronic structure, such as chemical bonding state, conduction band, band edge state below conduction band, and band alignment. Al-doped at ~ 10 at % showed not only a dramatic improvement of the electrical resistivity but also excellent chemical stability, both of which are strongly associated with changes of chemical bonding states and band edge states below the conduction band.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.921-926
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• 1997

SOI(Silicon On lnsulator) technology is many advantages in the gabrication of MOS(Metal-Oxide Semiconductor) and CMOS(Complementary MOS) structures. These include high speed, lower dynamic power consumption,greater packing density, increased radiation tolearence et al. In smiple form of bonded SOL wafer manufacturing, creation of a bonded SOI structure involves oxidizing at least one of the mirror polished silicon surfaces, cleaning the oxidized surface and the surface of the layer to which it will be bonded,bringing the two cleanded surfaces together in close physical proximity, allowing the subsequent room temperature bonding to proceed to completion, and than following this room temperature joining with some form of heat treatment step,and device wafer is thinned to the target thickness. This paper has been performed to investigate the possibility of the bonded SOI wafer manufacturing Especially, we focused on the bonding quality and thinning method. Finally,we achieved the bonded SOI wafer that Si layer thickness is below 3 .mu. m and average roughness is below 5.angs.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.205-206
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• 2006

A ball-shape alumina arc-tube for low-wattage lamp was developed by the PIM process. An ultra high purity translucentgrade alumina powder was used. In injection molding process, a hot-runner type mold was developed. The translucent-grade alumina powder was extremely sensitive to contamination so that the injection molding condition and atmosphere control in the furnace should be taken care of with extreme caution. Contamination sources were pinpointed with EPMA. The arc-tube was molded in half and two halves were bonded in the middle by a new bonding technique at room temperature developed in this study.

• Proceedings of the Korean Vacuum Society Conference
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• 2009.02a
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• pp.72.2-72.2
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• 2009

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.4
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• pp.395-403
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• 2012

This is direct bonding many of the metal bumps between FPCB and HPCB substrate. By using an ultrasonic horn mounted on an ultrasonic bonding machine, it is possible to bond gold pads onto the FPCB and HPCB at room temperature without an adhesive like ACA or NCA and high heat and solder. This ultrasonic bonding technology minimizes damage to the material. The process conditions evaluated for obtaining a greater bonding strength than 0.6 kgf, which is commercially required, were 40 kHz of frequency; 0.6MPa of bonding pressure; and 0.5, 1.0, 1.5, and 2.0 s of bonding time. The peel off test was performed for evaluating bonding strength, which was found to be more than 0.80 kgf.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.5
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• pp.365-371
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• 2003

We prepared silicon on insulator(SOI) wafer pairs of Si/1800${\AA}$ -SiO$_2$ ∥ 1800${\AA}$ -SiO$_2$/Si using water direct bonding method. Wafer pairs bonded at room-temperature were annealed by a normal furnace system or a fast linear annealing(FLA) equipment, and the micro-structure of bonding interfaces for each annealing method was investigated. Upper wafer of bonded pairs was polished to be 50 $\mu\textrm{m}$ by chemical mechanical polishing(CMP) process to confirm the real application. Defects and bonding area of bonded water pairs were observed by optical images. Electrical and mechanical properties were characterized by measuring leakage current for sweeping to 120 V, and by observing the change of wafer curvature with annealing process, respectively. FLA process was superior to normal furnace process in aspects of bonding area, I-V property, and stress generation.

• Journal of Powder Materials
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• v.24 no.3
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• pp.248-253
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• 2017

In this study, we investigate the effect of the diffusion barrier and substrate temperature on the length of carbon nanotubes. For synthesizing vertically aligned carbon nanotubes, thermal chemical vapor deposition is used and a substrate with a catalytic layer and a buffer layer is prepared using an e-beam evaporator. The length of the carbon nanotubes synthesized on the catalytic layer/diffusion barrier on the silicon substrate is longer than that without a diffusion barrier because the diffusion barrier prevents generation of silicon carbide from the diffusion of carbon atoms into the silicon substrate. The deposition temperature of the catalyst and alumina are varied from room temperature to $150^{\circ}C$, $200^{\circ}C$, and $250^{\circ}C$. On increasing the substrate temperature on depositing the buffer layer on the silicon substrate, shorter carbon nanotubes are obtained owing to the increased bonding force between the buffer layer and silicon substrate. The reason why different lengths of carbon nanotubes are obtained is that the higher bonding force between the buffer layer and the substrate layer prevents uniformity of catalytic islands for synthesizing carbon nanotubes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.4756-4762
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• 2014

Damaged wind turbine blades are repaired conventionally using a hand lay-up method with epoxy, where the bonding strength is not high. Epoxy has poor curing characteristics at low temperatures. The infusion method with polyester was proposed. Infusion method is believed to distribute resin uniformly. Polyester is used because it hardens better than epoxy at low temperatures. At room temperature, the proposed method increased the bonding strength by 77.7% compared to the conventional method. Using the proposed method at 15 and $5^{\circ}C$, the bonding strength increased compared to the conventional method. This paper proposes a new method for repairing wind turbine blades, even at temperatures where the conventional method cannot be used because epoxy resin does not harden. The bonding strength of the proposed method at low temperatures is higher than that of the conventional method at room temperature.