• Transactions of Materials Processing
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• v.18 no.4
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• pp.342-346
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• 2009

Forming characteristics for the bundle extrusion of Cu-Ti bimetal wires are investigated, which can identify the process conditions for weak mechanical bonding at the contact surface during the direct extrusion of a Cu-Ti bimetal wire bundle. Bonding mechanism between Cu and Ti is assumed as a cold pressure welding. Then, the plastic deformation at the contact zone causes mechanical bonding and a new bonding criterion for pressure welding is developed as a function of the principal stretch ratio and normal pressure at the contact surface by analyzing micro local extrusion at the contact zone. The averaged deformation behavior of Cu-Ti bimetal wire is adopted as a constitutive behavior at a material point in the finite element analysis of Cu-Ti wire bundle extrusion. Various process conditions for bundle extrusions are examined. The deformation histories at the three points, near the surface, in the middle and near the center, in the cross section of a bundle are traced and the proposed new bonding criterion is applied to predict whether the mechanical bonding at the Cu-Ti contact surface happens. Finally, a process map for the direct extrusion of Cu-Ti bimetal wire bundle is proposed.

• Journal of Technologic Dentistry
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• v.33 no.1
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• pp.47-54
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• 2011

Purpose: To investigate shear bonding strength between dental zirconia ceramics with different surface treatment and metal bracket. Methods: Zirconia ceramics(LAVA, 3M ESPE, USA) were divided to 4 groups according to their surface treatment; no surface treatment(G1), sand blasting(G2), silane coating(G3), and sand blasting+silane coating(G4). Specimens were bonded to metal bracket using resin bond($Transbond^{TM}XT$, 3M Unitek, USA). Shear bond strength was measured using universal test machine(3366 INSTRON. U.S.A) with cross head speed of 1 mm/min. Microstructural investigation for fracture surface was performed after shear test. Results: Shear bonding strengths of single surface treatment groups (G2 and G3) were higher than no treatment group(G1). Combined Treatment Group (G4) showed the highest shear bond strength of 9.15MPa. Microstructural observation shows that higher shear bonding strength was obtained when debonding was occurred at metal bracket/resin interface rather than zirconia ceramic/resin interface. Conclusion: Surface treatment of zirconia is necessary to obtain higher bonding strength. Combined treatment can be more effective when surface the surfaces are kept clean and homogeneous.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1501_1502
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• 2009

Plasma treatment time was optimized to maximize the bonding strength between silicon and quartz. Bonding strength between the silicon and quartz is related to a surface energy which can be calculated by contact angle measurement. It was found that optimized time to get maximized surface energy was 15 sec. Silicon and quartz wafers were treated with $O_2$ plasma under different time splits and then bonded together. Bonding strength of the bonded wafers was measured by shear test. It was verified that the highest bonding strength was obtained when the silicon and quartz wafers were treated for 15 seconds. The maximum bonding strength exceeded the fracture strength of silicon.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.164-167
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• 2002

SiC direct bonding technology is very attractive for both SiCOI(SiC-on-insulator) electric devices and SiC-MEMS applications because of its application possibility in harsh environments. This paper presents on pre-bonding according to HF pre-treatment conditions in SiC wafer direct bonding using PECVD oxide. The characteristics of bonded sample were measured under different bonding conditions of HF concentration, and applied pressure. The 3C-SiC epitaxial films grown on Si(100) were characterized by AFM and XPS, respectively. The bonding strength was evaluated by tensile strength method. Components existed in the interlayer were analyzed by using FT-IR. The bond strength depends on the HF pre-treatment condition before pre-bonding (Min : 5.3 kgf/$\textrm{cm}^2$∼Max : 15.5 kgf/$\textrm{cm}^2$).

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.4
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• pp.275-280
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• 1999

The glass-to-glass electrostatic bonding process in vacuum environment was developed and the tubeless-packaged FED was fabricated based on the bonding process. The fabricated tubeless-packaged FED showed stable field emission characteristics and potential applicability to the FED tubeless packaging and vacuum in-line sealing.

• Journal of the Korean institute of surface engineering
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• v.56 no.3
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• pp.180-184
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• 2023

Scholars have proposed wafer-level bonding and three-dimensional (3D) stacked integrated circuit (IC) and have investigated Cu-Cu bonding to overcome the limitation of Moore's law. However, information about quantitative Cu-Cu direct-bonding conditions, such as temperature, pressure, and interfacial adhesion energy, is scant. This study determines the optimal temperature and pressure for Cu-Cu bonding by varying the bonding temperature to 100, 150, 200, 250, and 350 ℃ and pressure to 2,303 and 3,087 N/cm². Various conditions and methods for surface treatment were performed to prevent oxidation of the surface of the sample and remove organic compounds in Cu direct bonding as variables of temperature and pressure. EDX experiments were conducted to confirm chemical information on the bonding characteristics between the substrate and Cu to confirm the bonding mechanism between the substrate and Cu. In addition, after the combination with the change of temperature and pressure variables, UTM measurement was performed to investigate the bond force between the substrate and Cu, and it was confirmed that the bond force increased proportionally as the temperature and pressure increased.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.609-615
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• 2001

This study proposes analysis and evaluation method of time series ultrasonic signal using attractor analysis for fusion joint part of polyethylene piping. Quantitatively characteristics of fusion joint part is analysed features extracted from time series. Trajectory changes in the attractor indicated a substantial difference in fractal characteristics. These differences in characteristics of fusion joint part enables the evaluation of unique characteristics of fusion joint part. In quantitative fractal feature extraction, feature values of 4.291 in the case of debonding and 3.694 in the case of bonding were proposed on the basis of fractal dimensions. In quantitative quadrant feature extraction, 1,306 point in the case of bonding(one quadrant) and 1,209 point(one quadrant) in the case of debonding were proposed on the basis of fractal dimensions. Proposed attractor feature extraction can be used for integrity evaluation of polyethylene piping material which is in case of bonding or debonding.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.2
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• pp.106-111
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• 2007

In this research work attempts were made to study the bonding of thermo-plastics with adhesives using solar radiation. In order to study the curing behaviour necessary experiments were conducted under varying conditions of temperature, exposure time and power of solar energy. The cured samples were then studied under the optical microscope before subjecting to tensile testing in order to study their mechanical properties of thermo-plastics. The fracture surfaces were further studied under the Scanning Electron Microscopy(SEM) in order to research the microstructural changes that are taken place during curing. In order to measure the performance of solar energy cured joints the parameters such as; bond strength, surface morphology, the microstructual changes, variation in properties of adhesives bonded joints are compared to that of specimen cured at ambient conditions and specimen cured using microwave techniques.

• Journal of Welding and Joining
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• v.20 no.4
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• pp.498-504
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• 2002

Fluxless flip chip bonding process using plasma treatment instead of flux was investigated. The effect of plasma process parameters on tin-oxide etching characteristics were estimated with Auger depth profile analysis. The die shear test was performed to evaluate the adhesion strength of the flip chip bonded after plasma treatment. The thickness of oxide layer on tin surface was reduced after Ar+H2 plasma treatment. The addition of H2 improved the oxide etching characteristics by plasma. The die shear strength of the plasma-treated Sn-Pb solder flip chip was higher than that of non-treated one but lower than that of fluxed one. The difference of the strength between plasma-treated specimen and non-treated one increased with increase in bonding temperature. The plasma-treated flip chip fractured at solder/TSM interface at low bonding temperature while the fracture occurred at solder/UBM interface at higher bonding temperature.

• Journal of Powder Materials
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• v.28 no.1
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• pp.1-6
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• 2021

Accurate and effective powder compaction analyses are performed for brittle materials such as graphite, utilized as a solid lubricant, by using the discrete element method (DEM). The reliability of the DEM analysis is confirmed by comparing the results of graphite powder compaction analyses using the DEM particle bonding contact model and particle non-bonding contact model with those from the powder compaction experiment under the same conditions. To improve the characteristics, the parameters influencing the compaction properties of the metal-graphite mixtures are explored. The compressibility increases as the size distribution of the graphite powder increases, where the shape of the graphite particles is uniform. The improved compaction characteristics of the metal-graphite (bonding model) mixtures are further verified by the stress transmission and compressive force distribution between the top and bottom punches. It is confirmed that the application of graphite (bonding model) powders resulted in improved stress transmission and compressive force distribution of 24% and 85%, respectively.