• Title, Summary, Keyword: Film Thickness

Search Result 3,680, Processing Time 0.048 seconds

In-Situ Electrical Resistance and Microstructure for Ultra-Thin Metal Film Coated by Magnetron Sputtering (마그네트론 스파터시 금속 극박막의 실시간 전기저항과 미세구조 변화)

  • Kwon, Na-Hyun;Kim, Hoi-Bong;Hwang, Bin;Bae, Dong-Su;Cho, Young-Rae
    • Korean Journal of Materials Research
    • /
    • v.21 no.3
    • /
    • pp.174-179
    • /
    • 2011
  • Ultra-thin aluminum (Al) and tin (Sn) films were grown by dc magnetron sputtering on a glass substrate. The electrical resistance R of films was measured in-situ method during the film growth. Also transmission electron microscopy (TEM) study was carried out to observe the microstructure of the films. In the ultra-thin film study, an exact determination of a coalescence thickness and a continuous film thickness is very important. Therefore, we tried to measure the minimum thickness for continuous film (dmin) by means of a graphical method using a number of different y-values as a function of film thickness. The raw date obtained in this study provides a graph of in-situ resistance of metal film as a function of film thickness. For the Al film, there occurs a maximum value in a graph of in-situ electrical resistance versus film thickness. Using the results in this study, we could define clearly the minimum thickness for continuous film where the position of minimum values in the graph when we put the value of Rd3 to y-axis and the film thickness to x-axis. The measured values for the minimum thickness for continuous film are 21 nm and 16 nm for sputtered Al and Sn films, respectively. The new method for defining the minimum thickness for continuous film in this study can be utilized in a basic data when we design an ultra-thin film for the metallization application in nano-scale devices.

The Influence of Engine Operating Conditions and Lubricants on Oil Film Thickness of Engine Connecting Rod Bearing (커넥팅로드 베어링의 유막두께에 미치는 기관 운전조건 및 윤활유의 영향)

  • Lee, D.H.;Chang, B.J.
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.2 no.5
    • /
    • pp.1-10
    • /
    • 1994
  • By applying of total electric capacitance method on engine connecting rod bearing during engine operating, the influence of engine operating conditions and lubricants on bearing oil film thickness was investigated. Minimum oil film thickness increases with kinematic viscosity, but as increasing of viscosity, the increasing ratio of film thickness is reduced. Also minimum oil film thickness increases with engine speed but there is a limit. Above this limit, film thickness decreases in opposition because of crankshaft inertia. As increasing of engine torque and oil temperature, munimum oil film thickness decreases linearly. For non-Newtonian oils, the correlation between $100{\circ}C$ kinematic viscosity and munimum oil film thickness is very poor.

  • PDF

Dynamic Elastohydrodynamic Film Thickness in Rocker-Arm Valve Train System (로커암 밸브 트레인의 동적 탄성유체윤활 유막 연구)

  • 장시열;이희락
    • Tribology and Lubricants
    • /
    • v.19 no.4
    • /
    • pp.195-202
    • /
    • 2003
  • Many computational researches have been performed about EHL film thickness in the contact between cam and follower in the engine valve train system. However, those computations do not explain the characteristics of dynamic film thickness which means squeeze film effect. Without the consideration of transient term in the Reynold's equation, the predicted film thickness from steady state condition has large difference from the actual film thickness. In this study, we have investigated the kinematic and dynamic simulations of rocker-arm valve train system. From the dynamic simulation, the applied load and the entraining velocity of the lubricant between cam and follower are obtained and with these values the dynamic film thickness is computed by Newton-Raphson method and compared with the steady state film thickness.

Dynamic Elastohydrodynamic Film Thickness in Rocker-Arm Valve Train System (로커암 밸브 트레인의 동적 탄성유체윤활 유막 연구)

  • 이희락;장시열
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
    • /
    • /
    • pp.397-405
    • /
    • 2000
  • Many computational researches have been performed about EHL film thickness in the contact between cam and follower. However, those computations do not explain the characteristics of dynamic film thickness which means squeeze film effect. Without the consideration of transient term in the Reynold's equation, the predicted film thickness has large difference from the actual film thickness. In this study, we have investigated the kinematic and dynamic simulations of rocker-arm valve train system. From the simulation, the applied load and the entraining velocity of the lubricant between cam and follower are obtained and with these values the dynamic film thickness is computed by Newton-Raphson method and compared with the steady state film thickness.

  • PDF

Fast Analysis of Film Thickness in Spectroscopic Reflectometry using Direct Phase Extraction

  • Kim, Kwangrak;Kwon, Soonyang;Pahk, Heui Jae
    • Current Optics and Photonics
    • /
    • v.1 no.1
    • /
    • pp.29-33
    • /
    • 2017
  • A method for analysis of thin film thickness in spectroscopic reflectometry is proposed. In spectroscopic reflectometry, there has been a trade-off between accuracy and computation speed using the conventional analysis algorithms. The trade-off originated from the nonlinearity of spectral reflectance with respect to film thickness. In this paper, the spectral phase is extracted from spectral reflectance, and the thickness of the film can be calculated by linear equations. By using the proposed method, film thickness can be measured very fast with high accuracy. The simulation result shows that the film thickness can be acquired with high accuracy. In the simulation, analysis error is lower than 0.01% in the thickness range from 100 nm to 4 um. The experiments also show good accuracy. Maximum error is under $40{\AA}$ in the thickness range $3,000-20,000{\AA}$. The experiments present that the proposed method is very fast. It takes only 2.6 s for volumetric thickness analysis of 640*480 pixels. The study suggests that the method can be a useful tool for the volumetric thickness measurement in display and semiconductor industries.

An Evaluation of the Hamrock and Dowson's EHL Film Thickness Formulas (Hamrock과 Dowson의 EHL 유막두께식에 대한 평가)

  • 박태조
    • Tribology and Lubricants
    • /
    • v.12 no.3
    • /
    • pp.115-122
    • /
    • 1996
  • In this paper, a finite difference method and the Newton-Raphson method are used to evaluate the Hamrock and Dowson's EHL film thickness formulas in elliptical contact problems. The minimum and central film thicknesses are compared with the Hamrock and Dowson's numerical results for various dimensionless parameters and with their film thickness formulas. The results of present analysis are more accurate and physically reasonable. The minimum film thickness formula is similar with the Hamrock and Dowson's results, however, the central film thickness formula shows large differences. Therefore, the Hamrock and Dowson's central film thickness formula should be replaced by following equation. $H_{c} = 4.88U^{0.68}G^{0.44}W^{0.096}(1-0.58e^{-0.60k})$ More accurate film thickness formula for general elliptical contact problems can be expected using present numerical methods and further research should be required.

Effects of Processing Conditions on Thickness Distribution for a Laminated Film during Vacuum-Assisted Thermoforming (열진공성형 공형조건이 적층필름의 두께분포에 미치는 영향)

  • Yoo, Y.G.;Lee, H.S.
    • Transactions of Materials Processing
    • /
    • v.20 no.3
    • /
    • pp.250-256
    • /
    • 2011
  • Vacuum-assisted thermoforming is one of the critical steps for the successful application of film insert molding(FIM) to parts of complex shapes. If the thickness distribution of the formed film is non-uniform, cracking, deformation, warping, and wrinkling can easily occur at the injection molding stage. In this study, the effects of processing parameters, which include the film heating time, plug depth, plug speed and vacuum delay time, on film thickness distribution were investigated. It was found that the film thickness at the part sidewall decreases with increasing the film heating time and plug depth, but the thickness at the bottom was found to exhibit the opposite behavior. The film thickness of the sidewall was observed to increase at higher plug speed and vacuum delay time of 0 ~ 0.3sec.

Oil Film Thickness Measurement of Engine Bearing and Cam/tappet Contact in an Automotive Engine

  • Choi, Jae-Kwon;Min, Byung-Soon;Han, Dong-Chul
    • Tribology and Lubricants
    • /
    • v.11 no.5
    • /
    • pp.71-77
    • /
    • 1995
  • The capacitance technique was used to measure the minimum oil film thickness in engine bearing and the central oil film thickness between cam and tappet. This method is based on the measurement of total capacitance of oil film. For the measurement of the oil film thickness between cam and tappet, two surfaces were assumed to be flat and parallel within the Hertzian region and all the measured capacitance originated from this region. Shear rates from the measured minimum oil film thickness are over 10$^{6}$ sec$^{-1}$ in the greater part in both two cases. The minimum oil film thickness in engine bearing is larger than the surface roughness. Between cam and tappet it is mostly smaller than the surface roughness. In spite of the awkward restriction of the reliability of measured oil film thickness, it was known that the capacitance technique makes it possible to measure the oil film thickness in elastohydrodynamic and mixed lubrication regimes as well as in hydrodynamic regime. Therefore, it is also possible to classify the lubrication regimes based on the oil film thickness.

Thickness and Surface Measurement of Transparent Thin-Film Layers using White Light Scanning Interferometry Combined with Reflectometry

  • Jo, Taeyong;Kim, KwangRak;Kim, SeongRyong;Pahk, HeuiJae
    • Journal of the Optical Society of Korea
    • /
    • v.18 no.3
    • /
    • pp.236-243
    • /
    • 2014
  • Surface profiling and film thickness measurement play an important role for inspection. White light interferometry is widely used for engineering surfaces profiling, but its applications are limited primarily to opaque surfaces with relatively simple optical reflection behavior. The conventional bucket algorithm had given inaccurate surface profiles because of the phase error that occurs when a thin-film exists on the top of the surface. Recently, reflectometry and white light scanning interferometry were combined to measure the film thickness and surface profile. These techniques, however, have found that many local minima exist, so it is necessary to make proper initial guesses to reach the global minimum quickly. In this paper we propose combing reflectometry and white light scanning interferometry to measure the thin-film thickness and surface profile. The key idea is to divide the measurement into two states; reflectometry mode and interferometry mode to obtain the thickness and profile separately. Interferogram modeling, which considers transparent thin-film, was proposed to determine parameters such as height and thickness. With the proposed method, the ambiguity in determining the thickness and the surface has been eliminated. Standard thickness specimens were measured using the proposed method. Multi-layered film measurement results were compared with AFM measurement results. The comparison showed that surface profile and thin-film thickness can be measured successfully through the proposed method.

A Study on the Circumferential Groove Effects on the Minimum Oil Film Thickness in Engine Bearings

  • Cho, Myung-Rae;Shin, Hung-Ju;Han, Dong-Chul
    • Journal of Mechanical Science and Technology
    • /
    • v.14 no.7
    • /
    • pp.737-743
    • /
    • 2000
  • This paper presents the effects of circumferential groove on the minimum oil film thickness in engine bearings. The fluid film pressures are calculated by using the infinitely short bearing theory for the convenience of analysis. Journal locus analysis is performed by using the mobility method. A comparison of minimum oil film thickness of grooved and ungrooved bearing is presented. It is found that circumferential $360^{\circ}$ groove only reduces the absolute magnitude of the oil film thickness, but $180^{\circ}$ half groove affects the shape of film thickness curve and position of minimum oil film thickness.

  • PDF