• 제목/요약/키워드: Blue-LED sapphire wafer

검색결과 5건 처리시간 0.019초

Scribing and cutting a sapphire wafer by laser-induced plasma-assisted ablation

  • Lee, Jong-Moo
    • 한국광학회:학술대회논문집
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    • 한국광학회 2000년도 제11회 정기총회 및 00년 동계학술발표회 논문집
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    • pp.224-225
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    • 2000
  • Transparent and hard materials such as sapphire are used for many industrial applications as optical windows, hard materials on mechanical contact against abrasion, and substrate materials for opto-electronic semiconductor devices such as blue LED and blue LD etc. The materials should be cut along the proper shapes possible to be used for each application. In case of blue LED, the blue LED wafer should be cut to thousands of blue LED pieces at the final stage of the manufacturing process. The process of cutting the wafer is usually divided into two steps. The wafer is scribed along the proper shapes in the first step. It is inserted between transparent flexible sheets for easy handling. And then, it is broken and split in the next step. Harder materials such as diamonds are usually used to scribe the wafer, while it has a problem of low depth of scribing and abrasion of the harder material itself. The low depth of scribing can induce failure in breaking the wafer along the scribed line. It was also known that the expensive diamond tip should be replaced frequently for the abrasion. (omitted)

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CMP 가공된 사파이어웨이퍼의 웨이퍼내 표면전위에 관한 연구 (A Study on the Zeta-potential of CMP processed Sapphire Wafers)

  • 황성원;신귀수;김근주
    • 한국정밀공학회지
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    • 제22권2호
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    • pp.46-52
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    • 2005
  • The sapphire wafer was polished by the implementation of the surface machining technology based on nano-tribology, The removal process has been performed by grinding, lapping and chemical-mechanical polishing. For the chemical mechanical polishing process, the chemical reaction between the slurry and sapphire wafer was investigated in terms of the change of Zeta-potential between two materials. The Zeta-potential was -4.98 mV without the slurry in deionized water and was -37.05 mV for the slurry solution. By including the slurry into the deionized water the Zeta-potential -29.73 mV, indicating that the surface atoms of sapphire become more repulsive to be easy to separate. The average roughness of the polished surface of sapphire wafer was ranged to 1∼4$\AA$.

Dislocation densities of CMP processed sapphire wafers for GaN epitaxy

  • 황성원;남정환;신귀수;김근주;서남섭
    • 한국반도체및디스플레이장비학회:학술대회논문집
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    • 한국반도체및디스플레이장비학회 2003년도 춘계학술대회 발표 논문집
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    • pp.18-22
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    • 2003
  • The sapphire wafers for blue light emitting devices were manufactured by the implementation of the surface machining technology based on micro-tribology. This process has been performed by grinding, lapping and polishing. The surfaces of sapphire wafers were mechanically affected by residual stress and surface default. This mechanical stress and strain can be cured by thermal anneal ing process. The sapphire crystalline wafers were annealed at $1100~1400^{\circ}C$ and then characterized by double crystal X-ray diffraction. The sample showed good quality of crystalline wafer surface wi th full width at hal f maximum of 16 arcsec for the 4-hour heat-treatment at $1300^{\circ}C$.

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GaN 증착용 사파이어 웨이퍼의 표면가공에 따른 압흔 특성 (Surface Lapping Process and Vickers Indentation of Sapphire Wafer for GaN Epitaxy)

  • 신귀수;황성원;김근주
    • 대한기계학회논문집A
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    • 제29권4호
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    • pp.632-638
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    • 2005
  • The surface lapping process on sapphire wafer was carried out for the epitaxial process of thin film growth of GaN semiconducting material. The planarization of the wafers was investigated by the introduction of the dummy wafers. The diamond lapping process causes the surface deformation of dislocation and micro-cracks. The material deformation due to the mechanical stress was analyzed by the X-ray diffraction and the Vickers indentation. The fracture toughness was increased with the increased annealing temperature indicating the recrystallization at the surface of the sapphire wafer The sudden increase at the temperature of $1200^{\circ}C$ was correlated with the surface phase transition of sapphire from a $-A1_{2}O_{3}\;to\;{\beta}-A1_{2}O_{3}$.

Design of Alignment Mark Stamper Module for LED Post-Processing

  • Hwang, Donghyun;Sohn, Young W.;Seol, Tae-ho;Jeon, YongHo;Lee, Moon G.
    • 한국생산제조학회지
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    • 제24권2호
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    • pp.155-159
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    • 2015
  • Light emitting devices (LEDs) are widely used in the liquid crystal display (LCD) industry, especially for LCD back light units. Therefore, much research has been performed to minimize manufacturing costs. However, the current process does not process LED chips from broken substrates even though the substrate is expensive sapphire wafer. This is because the broken substrates lose their alignment marks. After pre-processing, LED dies are glued onto blue tape to continue post-processing. If auxiliary alignment marks are stamped on the blue tape, post-processing can be performed using some of the LED dies from broken substrates. In this paper, a novel stamper module that can stamp the alignment mark on the blue tape is proposed, designed, and fabricated. In testing, the stamper was reliable even after a few hundred stamps. The module can position the stamp and apply the pattern effectively. By using this module, the LED industry can reduce manufacturing costs.