• Title, Summary, Keyword: Polymeric substrate

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Athermalized Polymeric Arrayed-Waveguide Grating by Partial Detachment from a Si Substrate

  • Lee, Jong-Moo;Ahn, Joon-Tae;Park, Sun-Tak;Lee, Myung-Hyun
    • ETRI Journal
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    • v.26 no.3
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    • pp.281-284
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    • 2004
  • We demonstrate a new fabrication method for adjusting the temperature dependence of a polymeric arrayed-waveguide grating (AWG) on a Si substrate. A temperature-dependent wavelength shift of-0.1nm/$^{\circ}C$ in a polymeric AWG on a Si substrate is reduced of+0.1nm/$^{\circ}C$ by detaching part of the polymer film, including the grating channel region of the AWG, from the Si substrate while the other parts remain fixed on the substrate.

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Micro Pattern Forming on Polymeric Circular Tubes by Hydrostatic Pressing (폴리머 원형 튜브 대상 미세 패턴 정수압 성형)

  • Rhim, S.H.
    • Transactions of Materials Processing
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    • v.23 no.8
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    • pp.507-512
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    • 2014
  • The objective of the current investigation is to establish techniques in micro pattern forming operations of polymeric circular tubes by using hydrostatic pressing. This method was developed and successfully applied to the micro pattern forming on polymeric plates. The key idea of the new technique is to pressurize multiple vacuum-packed substrate-mold stacks above the glass transition temperature of the polymeric substrates. The new process is thought to be a promising micro-pattern fabrication technique for two reasons; first, (hydro-) isostatic pressing ensures a uniform micro-pattern replicating condition regardless of the substrate area and thickness. Second, multiple curved substrates can be patterned at the same time. With the prototype forming machine for the new process, micro prismatic array patterns, 25um in height and 90 degrees in apex angle, were successfully made on the PMMA circular tubes with diameters of 5~40mm. These results show that this process can be also used in the micro pattern forming process on curved plates such as circular tube.

Viscoelastic Analysis of an Interface Edge Crack in a Bonded Polymeric Film

  • Lee, Sang-Soon
    • Journal of the Semiconductor & Display Technology
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    • v.9 no.3
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    • pp.35-39
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    • 2010
  • Interfacial stress singularity induced in an analysis model consisting of the polymeric thin film and the elastic substrate has been investigated using the boundary element method. The interfacial singular stresses between the viscoelastic thin film and the elastic substrate subjected to a uniform moisture ingression are investigated for the case of a small interfacial edge crack. It is assumed that moisture effects are assumed to be analogous to thermal effects. Then, the overall stress intensity factor for the case of a small interfacial edge crack is computed. The numerical procedure does not permit calculation of the limiting case for which the edge crack length vanishes.

Measurement of Material Property of Thin Film and Prediction of Residual Stress using Laser Scanning Method (레이저 주사법을 이용한 박막 물성 측정 및 잔류응력 예측)

  • Lee, Sang-Soon
    • Journal of the Microelectronics and Packaging Society
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    • v.11 no.4
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    • pp.49-53
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    • 2004
  • Polymeric materials are widely used in the electronic industry as a common dielectric material or adhesive. The polymeric layer coated on Si substrate can be subjected to thermal stresses due to difference in thermal expansion coefficients. The mismatch in thermal properties between the polymeric layer and the substrate results in significant residual stresses. In this study, the thermal deformation is measured by a curvature measurement method using laser scanning, and the elastic modulus is calculated by an analytic model.

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Development of Polymeric Layer for Enhancing The Adhesion of Nano-devices Fabricated by The Nanotransfer Molding Method

  • Lee, Gi-Seok;Seong, Myeong-Mo
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.634-634
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    • 2013
  • Transfer molding methods have a problem that weak adhesion between nanostructures and substrates. It is important to make various nano scale applications, also the stability of nanostructure on substrate is related with device performance. We studied an effect of poly 4-vinylphenol (PVP) as the polymeric adhesion layer between organic nanowires and a Si substrate when the nanowires are transferred by liquid-bridge-mediated nanotransfer molding method (LB-nTM). Their structural stability was examined by optical microscopy, scanning electron microscopy as multiple transfer molding and washing process. Field-effect transistors were fabricated with organic semiconductor nanowires on a polymeric adhesion layer and their electrical properties showed no significant difference as the one without the adhesion layer. As a result, adhesion layer can be used in the washing process and making multi-layer nano-scale patterns.

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Stress Analysis in Polymeric Coating Layer Deposited on Rigid Substrate

  • Lee, Sang Soon
    • Corrosion Science and Technology
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    • v.14 no.4
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    • pp.161-165
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    • 2015
  • This paper presents an analysis of thermal stress induced along the interface between a polymeric coating layer and a steel substrate as a result of uniform temperature change. The epoxy layer is assumed to be a linear viscoelastic material and to be theromorheologically simple. The viscoelastic boundary element method is employed to investigate the behavior of interface stresses. The numerical results exhibit relaxation of interface stresses and large stress gradients, which are observed in the vicinity of the free surface. Since the exceedingly large stresses cannot be borne by the polymeric coating layer, local cracking or delamination can occur at the interface corner.

Characteristics of ITO/polymeric Films with Change of Oxygen Partial Pressure (산소분압의 변화에 따른 ITO/polymeric 박막의 특성)

  • 신성호;김현후
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.8
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    • pp.846-851
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    • 2004
  • Transparent conducting indium tin oxide (TC-ITO) thin films on polymeric substrates have been deposited by a dc reactive magnetron sputtering without heat treatments. The polymeric substrates are acryl (AC), poly carbornate (PC), and polyethlene terephthalate (PET) as well as soda lime glass is also used to compare with the polymeric substrates. Sputtering parameters are an important factor for high quality of TC-ITO thin films prepared on polymeric substrates. Furthermore, the material, electrical and optical properties of as-deposited ITO films are dominated by the ratio of oxygen partial pressure. As the experimental results, the surface roughness of ITO films becomes rough as the oxygen partial pressure increases. The electrical resistivity of as-deposited ITO films decreases initially, and then increases with the increase of oxygen partial pressure. The optical transmittance at visible wavelength for all polymeric substrates is above 82 %.

Mechanisms of Platelet Adhesion on Elastic Polymer Surfaces: Protein Adsorption and Residence Effects

  • Insup Noh;Lee, Jin-Hui
    • Macromolecular Research
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    • v.9 no.4
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    • pp.197-205
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    • 2001
  • Platelet adhesion onto elastic polymeric biomaterials was tested in vitro by perfusing human whole blood at a shear rate of 100 sec$\^$-1/ for possible verification of mechanisms of initial platelet adhesion perfusion of blood on the polymeric substrates was performed after treatments either with or without pre-adsorption of 1% blood plasma, and either with or without residence of the protein-preadsorbed substrate in phosphate buffered solution. The surfaces employed were elastic polymers such as poly(ether urethane urea), poly(ether urethane), silicone urethane copolymer, silicone rubber and poly(ether urethane) with the anti-calcifying agent hydroxyethane bisphosphate. Each polymer surface treated was exposed in vitro to the dynamic, heparinized whole blood perfused for upto 6 min and the surface area of platelets initially adhered was measured by employing in situ epifluorescence video microscopy. The blood perfusion was performed on the surfaces treated at the following three different conditions: directly on the bare surfaces, after protein pre-adsorption and after residence in buffer for 3 days of the surfaces protein pre-adsorbed for 2 h. The effects of blood plasma pre-adsorption on the initial platelet adhesion was surface-dependent. The amount of the adsorbed fibrinogen and the surface coverage area of the adhered platelets were dependent on the surface conditions whether substrates were bare surfaces or protein pre-adsorbed ones. To test an effect of possible morphological (re)orientations of the adsorbed proteins on the initial platelet adhesion, the polymeric substrate pre-adsorbed with 1% blood plasma was immersed in phosphate buffered solution for 3 days and then exposed to physiological blood perfusion. The surface area of the platelets adhered on these surfaces was significantly different from that of the surfaces treated with protein pre-adsorption only. These results indicated that platelet adhesion was dependent on the surface property itself and pre-treatment conditions such as blood perfusion without any pre-adsorption of proteins, and blood perfusion either after protein pre-adsorption or after subsequent substrate residence in buffer of the substrate pre-adsorbed with proteins. Understanding of these results may guide for better designs of blood-contacting materials based on protein behaviors.

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Large-area Uniform Deposition of Amorphous Hydrogenated Carbon Films using a Plasma CVD Method (플라즈마 CVD 법을 이용한 대면적 균일한 비정질 탄소 막 증착)

  • Yun, Sang-Min;Yang, Sung-Chae
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.22 no.5
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    • pp.411-414
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    • 2009
  • It has been investigated for the film uniformity and deposition rate of a-C:H films on glass substrate and polymeric materials in the presence of the modulated crossed magnetic field. We used Plasma CVD, i.e, using a crossed electromagnetic field, for uniform depositing thin film. The optimum discharge condition has been discussed for the gas pressure, the magnetic flux density and the distance between substrate and electrodes, As a result, it is found that the optimum discharge conditions are $CH_4$ concentration $CH_4$=10 %, modulated magnetic flux density B=48 Gauss, pressure P=100 mTorr, discharge power supply voltage V=l kV under these experimental conditions. By using these experimental condition, it is possible to prepare the most uniform film extends over about 160 mm of the film width. In this study, we deposited a-C:H thin film on glass substrate, and have a plan that using this condition, study depositing a-C:H thin film on polymeric substrate in next studies.