• Title/Summary/Keyword: Laser cleaning

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The Evaluation of the atomic composition and the surface roughness of Titanium Implants following Various Laser treatment with air-powder abrasive (레이저 처리후 임프란트 표면 변화에 관한 연구)

  • Kim, Tae-Jung;Lim, Sung-Bin;Chung, Chin-Hyung
    • Journal of Periodontal and Implant Science
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    • v.32 no.3
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    • pp.615-630
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    • 2002
  • Various long-term studies have shown that titanium implants as abutments for different types of prostheses have become a predictable adjunct in the treatment of partially or fully edentulous patients. The continuous exposure of dental implants to the oral cavity with all its possible contaminants creates a problem. A lack of attachment, together with or caused by bacterial insult, may lead to peri-implantitis and eventual implant failure. Removal of plaque and calculus deposits from dental titanium implants with procedures and instruments originally made for cleaning natural teeth or roots may cause major alterations of the delicate titanium oxide layer. Therefore, the ultimate goal of a cleaning procedure should be to remove the contaminants and restore the elemental composition of the surface oxide without changing the surface topography and harming the surrounding tissues. Among many chemical and mechanical procedure, air-powder abrasive have been known to be most effective for cleaning and detoxification of implant surface. Most of published studies show that the dental laser may be useful in the treatment of pen-implantitis. $CO_2$ laser and Soft Diode laser were reported to kill bacteria of implant surface. The purpose of this study was to obtain clinical guide by application these laser to implant surface by means of Non-contact Surface profilometer and X-ray photoelectron spectroscopy(XPS) with respect to surface roughness and atomic composition. Experimental rough pure titanium cylinder models were fabricated. All of them was air-powder abraded for 1 minute and they were named control group. And then, the $CO_2$ laser treatment under dry, hydrogen peroxide and wet condition or the Soft Diode laser treatment under Toluidine blue O solution condition was performed on the each of the control models. The results were as follows: 1. Mean Surface roughness(Ra) of all experimental group was decreased than that of control group. But it wasn't statistically significant. 2. XPS analysis showed that in the all experimental group, titanium level were decreased, when compared with control group. 3. XPS analysis showed that the level of oxygen in the experimental group 1, 3($CO_2$ laser treatment under dry and wet condition) and 4(Soft Diode laser was used under toluidine blue O solution) were decreased, when compared with control group. 4. XPS analysis showed that the atomic composition of experimental group 2($CO_2$ laser treatment under hydrogen peroxide) was to be closest to that of control group than the other experimental group. From the result of this study, this may be concluded. Following air-powder abrasive treatment, the $CO_2$ laser in safe d-pulse mode and the Soft Diode laser used with photosensitizer would not change rough titanium surface roughness. Especially, $CO_2$ laser treatment under hydrogen peroxide gave the best results from elemental points of view, and can be used safely to treat peri-implantitis.

Improvement of the Electrical Characteristics of a Polysilicon TFT Using Buffered Oxide Etch Cleaning (Buffered Oxide Etch 세정에 의한 다결정 실리콘 TFT의 전기적 특성 개선)

  • 남영묵;배성찬;최시영
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.41 no.8
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    • pp.31-36
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    • 2004
  • we developed a technique to manufacture more reliable polycrystalline silicon TFT-LCDs using UV cleaning and buffered oxide etch(BOE) cleaning which remove the native oxide of the silicon surface before laser annealing. To investigate the effects of pre-treatments on the surface roughness of polycrystalline silicon, we measured atomic force microscopy(AFM). Also the electrical characteristics of polysilicon TFTs, breakdown characteristic and switching Performance, were tested for various pre-treatment conditions and several locations in large glass substrate.

Wafer cleaning efficiency by Laser Shock Wave (레이저충격파를 이용한 웨이퍼 세정)

  • Kang Y. J.;Lee S. H.;Park J. G.;Lee J. M.;Kim T. H.
    • Proceedings of the International Microelectronics And Packaging Society Conference
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    • 2003.11a
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    • pp.256-259
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    • 2003
  • To develop cleaning process various particles should be deposited on wafer surfaces to measure particle removal efficiencies. The purpose of the article in to evaluate, removal efficient)r of silica and alumina particles from wafer surfaces when they are deposited by dry and wet method. Dry deposition in air and wet spray deposition using solutions are used. van der Waals are considered to calculate the adhesion force of particles on surfaces. Higher adhesion force is measured on alumina particles on silicon when particles are deposited in air.

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Laser Processing Technology in Semiconductor and Display Industry (반도체 및 디스플레이 산업에서의 레이저 가공 기술)

  • Cho, Kwang-Woo;Park, Hong-Jin
    • Journal of the Korean Society for Precision Engineering
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    • v.27 no.6
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    • pp.32-38
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    • 2010
  • Laser material processing technology is adopted in several industry as alternative process which could overcome weakness and problems of present adopted process, especially semiconductor and display industry. In semiconductor industry, laser photo lithography is doing at front-end level, and cutting, drilling, and marking technology for both wafer and EMC mold package is adopted. Laser cleaning and de-flashing are new rising technology. There are 3 kinds of main display industry which use laser technology - TFT LCD, AMOLED, Touch screen. Laser glass cutting, laser marking, laser direct patterning, laser annealing, laser repairing, laser frit sealing are major application in display industry.

Design Optimization of Cleaning Blade for Minimizing Stress (응력 최소화를 위한 클리닝 블레이드 최적설계)

  • Park, Chang-Hyun;Lee, Jun-Hee;Choi, Dong-Hoon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.5
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    • pp.575-582
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    • 2011
  • A cleaning blade is an attachment installed in the toner cartridge of a laser printer for removing the residual toner from an organic photo-conductive drum. There have been many studies on the performance and life of the rubber blade. We focus on optimally designing the blade shape parameters to minimize the maximum stress of the blade while satisfying design constraints on the cleaning performance and part interference. The blade is optimally designed using a design of experiments, meta-models and an optimization algorithm implemented in PIAnO (process integration, automation, and optimization), a commercial PIDO (process integration and design optimization) tool. We integrate the CAE tools necessary for the structural analysis of the cleaning blade, automate the analysis procedure, and optimize the solution using PIAnO. We decreased the maximum stress by 32.6% in comparison with that of the initial design.

Improvement of Reproducibility in Selective Electrodeposition Using Laser Masking and DC Voltage (레이저 마스킹과 직류전원을 이용한 선택적 전해도금의 재현성 개선)

  • Shin, Hong Shik
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.25 no.1
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    • pp.36-41
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    • 2016
  • A method is proposed for the improvement of deposition reproducibility in the selective electrodeposition process using laser masking and DC voltage. Selective electrodeposition using laser masking and DC voltage can achieve a deposited layer with micro patterns. However, selective electrodeposition using laser masking and DC voltage have a critical problem: the lack of reproducibility in selective deposition. The reproducibility of selective electrodeposition can be improved by a new process that consists of laser masking, two-step electro-deposition, laser scribing, and ultrasonic cleaning. The experiments in this study show that the reproducibility of selective deposition can be successfully improved by the combination of two-step electrodeposition and laser scribing.