• 한국레이저가공학회지
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• 제15권1호
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• pp.6-9
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• 2012

In TFT-LCD manufacturing process, various defects are generated by manufacturing machine trouble or particle. These defects can be repaired through the TFT-Laser repair process that only can't be automated in TFT-LCD manufacturing Process. In this Paper, we propose auto defect algorithm for TFT-LCD laser repair machine using image processing algorithm in order to automate process. Proposed algorithm can detect very small defects (< 2um) in 98% success ratio, and generated laser repair path guarantee highly precise position accuracy. Through proposed system, much of the work still done the old-fashioned way, by hand, can be automated and manufacturing company can be strengthed the competitiveness of cost.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.56-60
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• 2008

Laser cladding technology was studied as a method for upgrading the present repair procedures of damaged tubes in a nuclear steam generator and Doosan subsequently developed and designed a new Laser Cladding Repair System. One of the important features of this newly developed Laser Cladding Repair System is that molten metal can be deposited on damaged tube surfaces using a laser beam and filler wire without the need to install sleeves inside the tube. Laser cladding qualification tests on the steam generator tube material, Alloy 600, were performed according to ASME Section IX. Residual stress analyses were performed for weld metal and heat affected zone of as-welded and PWHT with SYSWELD software.

• 대한전자공학회논문지SD
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• 제39권11호
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• pp.1-6
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• 2002

본 논문에서는 High speed DRAM의 speed 특성을 향상시키기 위한 Laser_Repair Condition 최적화의 한 방안을 구현하였다. 구현 방법은 먼저 Wafer내의 개별 Die별 DC Generator level을 확인하고 최약 DC Generator를 파악한 후 AC parameter의 margin을 check하고 AC parameter의 특성을 개선시킬 수 있는 DC Generator level을 forcing하여 test하여 개선 효과를 곧장 확인하였고 그에 대한 Fuse cutting inform을 생성하여 Laser_Repair 공정에서 적용하여 Post_Laser test시 개선 효과를 확인하였다.

• 한국정밀공학회지
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• 제27권11호
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• pp.7-16
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• 2010

In this study, wire was used as the filler material for the laser repair welding, and the phenomenon in which the supplied filler material was melted and beaded down into the specimen was examined with varying laser powers and welding speeds. The optimal processing condition was found to be the laser power of 1,300 W, the welding speed and feed wire supply speed of 0.5 ml/in and the defocused distances of +2mm. At this time, the heat input(E) was $65{\sim}75\;J/mm^2$, and no internal defect occurred. When repair welding was carried out as the optimal processing for the part that had an external defect with the radius of 2mm, the filler metal was melted, resulting in the volume smaller than the defect part and thus causing the part unfilled. Therefore, it was found to be necessary to carry out repair welding two to three times by multiple passes rather than does it only once by single pass.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2007년 추계학술발표대회 개요집
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• pp.196-198
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• 2007

Laser cladding technology was studied as a method for upgrading the present repair procedures of damaged tubes in a nuclear steam generator and Doosan subsequently developed and designed a new Laser Cladding Repair System. One of the important features of this newly developed Laser Cladding Repair System is that molten metal can be deposited on damaged tube surfaces using a laser beam and filler wire without the need to install sleeves inside the tube. Laser cladding qualification tests on the steam generator tube material, Alloy 600, were performed according to ASME Section IX.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.1263-1266
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• 2008

TFT-LCD panel makers have been enlarging size of TV screens, and 50-inch TFT-LCD is one of the main stream products already. To have more improved resolution, productivity and lower manufacturing cost, new TFT-LCD factories adopt large mother glass, new TFT structure and new process/materials. Along with these technology evolution, laser repair system should equip with upgraded performance and additional functions on user's demand. Laser repair technology is reviewed and newly developed repair technology is being introduced.

• 한국시뮬레이션학회논문지
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• 제18권4호
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• pp.59-66
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• 2009

VLSI(Very Large Scale Integration)와 WSI(Wafer Scale Integration)와 같은 통합기술로 인해 큰 용량의 메모리 대량생산이 가능 하게 된 지금 Redundancy는 메모리 칩의 제조와 결함이 있는 셀을 지닌 디바이스를 치료하는데 광범위하게 사용되어져왔다. 메모리칩의 밀도가 증가함에 따라 결함의 빈도 또한 증가한다. 많은 결함이 있다면 어쩔 수 없겠지만 적은 결함이 발생한 경우에는 해당 다이를 reject 시키는 것 보다는 수선해서 사용하는 것이 메모리생산 업체 입장에서는 보다 효율적이고 원가 절감 차원에서 필수적이다. 이와 같은 이유로 laser repair라는 공정이 필요하고 laser repair공정의 정확한 타깃을 설정하기 위해 redundancy analysis가 필요하게 되었다. CRA시뮬레이션은 기존의 redundancy analysis 알고리즘의 개념에서 벗어나 결함 유형별로 시뮬레이션한 후 RA를 진행함으로써 RA에 소요되는 시간을 절약함으로써 원가 경쟁력 강화를 할 수 있다.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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• pp.402-407
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• 2002

Laminate tooling process is a fast and simple method to make metal tools directly for various molding processes such as injection molding in rapid prototyping field. Metal sheets are usually cut, stacked, aligned and joined with brazing or soldering. Through the joining process, all of the metal sheet layers should be rigidly joined. When joining process parameters are not appropriate, there would be defects in the layers. Among various types of defects, non-bonded gaps of the tool surface are of great importance, because they directly affect the surface quality and dimensional accuracy of the final products. If a laminate tool with defects has to be abandoned, it could lead to great loss of time and cost. Therefore a repair method for non-bonded gaps of the surface is essential and has important meaning for rapid prototyping. In this study, a rapid laminate tooling system composed of a CO2 laser, a furnace, and a milling machine was developed. Metal sheets were joined by furnace brazing, dip soldering and adhesive bonding. Joined laminate tools were machined by a high-speed milling machine to improve surface quality. Also, repair brazing and soldering methods of the laminates using the $CO_2$ laser system have been investigated. ill laser repair process, the beam duration, beam power and beam profile were of great importance, and their effects were simulated by [mite element methods. The simulation results were compared with the experimental ones, and optimal parameters for laser repair process were investigated.

• 한국압력기기공학회 논문집
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• 제11권1호
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• pp.53-60
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• 2015

This study was investigated to develop process technology of laser cladding with austenite stainless steel for Weld Inlay repair of dissimilar metal weld in reactor vessel in/outlet nozzles. Weld Inlay experiments were performed by laser cladding repair system consisting of common manipulator, laser apparatus and welding process scheduler, etc. Single pass welding experiments were conducted in order to obtain the optimum welding process parameters for filler wires of ER309L and Alloy 52M before multi-layer laser cladding. Based on the above obtained results, multi-layer laser cladding experiments were carried out, and welding qualities for weld specimens were estimated by PT, OM, SEM and EDS analysis. Consequently, it was revealed that multi-layer laser cladding on austenite stainless steel using filler wires of ER309L and Alloy 52M could be possible to meet ASME Code standard without any weld defect.

• 한국전기전자재료학회논문지
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• 제17권10호
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• pp.1114-1119
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• 2004

The photodepositioned tungsten film by laser CVD has been carried out the taping test with scotch tape over 10 times. As a result, it exhibited strong adhesion to the under-film such as ITO and SiNx patterned on the LCD substrate. However, it was seriously attacked by alkaline solution used for removing polyimide. And a thickness of laser CVD tungsten film had a close relation to a speed of laser scanning. Also we have improved the success rate of a laser CVD repair with making two pairs of contact hole structure and decreasing laser scanning speed.