• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.10a
• /
• pp.61-61
• /
• 2003

• Proceedings of the Optical Society of Korea Conference
• /
• 1996.09a
• /
• pp.34-34
• /
• 1996

• Laser Solutions
• /
• v.6 no.1
• /
• pp.33-40
• /
• 2003

The ablative decomposition mechanism of PMMA(polymethyl methacrylate) and PET(polyethylene terephthalate) with KrF excimer laser(λ : 248nm, pulse duration: 5㎱) is investigated. The UV/Vis spectrometer analysis showed that PMMA is a weak absorber and PET is a strong absorber at the wavelength of 248nm. The results(surface debris, melt, etch depth, etching shape) from drilling and direct writing experiments imply that ablation mechanism of PMMA is dominated by photothermal process, while that of PET is dominated by photochemical process.

• Laser Solutions
• /
• v.6 no.2
• /
• pp.35-41
• /
• 2003

In this study, manufacturing of polymer master and mold insert for micro injection molding was investigated. Ablation by excimer laser radiation could be used successfully to make 3-D microstructure of PET. The mechanism for ablative decomposition of PET with KrF excimer laser(λ: 248nm, pulse duration: 5ns) was explained by photochemical process. And this process showed PET to be adopted in polymer master for nickel mold insert. Nickel electroforming by using laser ablated PET master was preferable for replication method. Finally, it was shown that excimer laser ablation can substitute for X-ray lithography of LIGA process in microstructuring.

• Proceedings of the KIEE Conference
• /
• 2002.07c
• /
• pp.1612-1614
• /
• 2002

본 논문에서는 엑시머 레이저 조사에 의한 이온 농도의 분포 변화를 알아보기 위해 붕소 이온이 선택적으로 주입된 비정질 실리콘 박막 위에 XeCl (${\lambda}$=308nm) 엑시머 레이저를 조사하여 붕소이온의 수평 확산 현상을 관찰하였다. 도핑 농도의 분포를 알아보기 위해 불산/질산 용액에 의한 고농도 도핑 영역의 습식 식각을 이용하여 약 $10^{18}/cm^3$ 이하의 붕소이온을 가지는 실리콘 박막의 형태를 전자주사 현미경을 이용해서 관찰하였다. 실험 결과, $200mJ/cm^2$의 레이저 에너지가 조사될 경우, 약 100nm의 수평 확산이 일어났음을 확인 할 수 있었다.

• Proceedings of the Korean Society of Laser Processing Conference
• /
• 2006.11a
• /
• pp.96-102
• /
• 2006

In this study, manufacturing of polymer master, PDMS(poly dimethylsiloxane) transfer mold, and mold insert was investigated for laser LIGA(LIthography Calvanoformung Abformtechnik). Initially, ablation by excimer laser radiation was used successfully to make 3-D microstructure of PET. After then, the PDMS transfer mold was replicated using ablated PET. Finally, epoxy resin tooling on replicated PDMS transfer mold was executed for making mold insert. From these facts we can conclude that excimer laser ablation of polymer and fabricaiton of PDMS transfer mold are reasonable tools to substitute for X-ray lithography of LIGA process in microstructuring.

• Journal of the Korean Vacuum Society
• /
• v.13 no.1
• /
• pp.29-33
• /
• 2004

In this paper, we investigated the ultra-low temperature(<$150^{\circ}C$) polycrystalline silicon film on plastic substrate application using RF-magnetron sputtering and excimer laser annealing. Amorphous silicon films were deposited using Ar/He mixture gas at $120^{\circ}C$ and in-film argon concentration was less than 2%, which was measured to Rutherford Backscattering Spectrometry. At energy density 320mJ/$\textrm{cm}^2$, RMS roughness was 267$\AA$ and UV crystallinity was 62%. The grain size varies from 50nm to 100nm after excimer laser irradiation.

• Korean Journal of Materials Research
• /
• v.7 no.10
• /
• pp.908-913
• /
• 1997

플라즈마 화학 증착 방법에 의해 corning 7059 유리기판위에 비정질 실리콘 박막을 만들고 고온열처리, 다단계급속열처리, 일차원 선형빔(line shape beam)의 가우스 분포를 가지는 엑시머 레이저 열처리를 이용하여 고상 및 액상의 재결정화를 통해 다결정 실리콘 박막을 제작하였다. 편광된 라만 분광학(Raman spectroscopy)을 통하여 여러 가지 열처리 방법과 기판온도에 따른 다결정 실리콘 박막의 잔류응력을 조사하였다. 레이저 열처리에 의하여 결정화된 실리콘 기판의 경우, 높은 결정화된 체적량과 잔류응력을 갖으며 equaxial결정성을 갖는다. 그러나 이러한 고상 재결정화된 다결정 실리콘 박막은 라만스펙트럼에서 480$cm^{-1}$ /주위에 넓게 퍼져있어 비정질상(amorphous phase)이 함께 존재함을 알 수 있다. 고온열처리와 다단계급속열처리의 경우 잔류응력의 크기는 각각 4.07x$10^{9.}$과 4.56x$10^{9 dyne}$ $\textrm{cm}^2$이다. 또한 엑시머레이저 열처리의 경우 기판온도가 상온에서 40$0^{\circ}C$로 증가할수록 열적인 완화에 의해 잔류응력이 1.35x$10^{10}$에서 8.58x$10^{9}$dyne/$\textrm{cm}^2$으로 감소하는 것을 알 수 있다.다.

• Proceedings of the Acoustical Society of Korea Conference
• /
• 1993.06a
• /
• pp.29-33
• /
• 1993

펄스레이저를 고체표면에 조사하면 광-음향효과에 의해 입사지점에서 음향파원이 형성되고 음향파원의 형태와 재료의 특성에 따라 여러 유형의 종파, 횡파 및 표면파의 음향에너지가 발생된다. 본 연구에서는 열탄성영역과 플라스마영역에서 종파와 횡파의 변위파형을 해석하여 모의실험을 수행하였다. 실험에서는 KrF엑시머레이저를 탄소강, 알루미늄, 황동에 조사하여 플라스마영역에서의 광-음향신호를 검출하였으며 이론과 비교하여 분석하였다.

• Korean Journal of Optics and Photonics
• /
• v.7 no.3
• /
• pp.232-237
• /
• 1996

A 500 Hz repetition rate excimer laser was developed as light source for pollution lidar. In this paper, the high repetitive output characteristics, the gas flow loop structure, and CR(clearing ratio) characteristics were investigated. Our laser system was constructed compact structure with a streamline gas flow loop and UV preionization. The real gas volume of laser is 10 liter. At 500 Hz repetitive operation, we have obtained average power of 53 watt with KrF laser gas. The variation of laser output, CR, and active volume are $\pm$6.7%, 2.3, and 2.0(H)$\times$1.2(W)$\times$56(L)=134 ㎤, respectively. Laser output power is declined to half at 3$\times$$10^6$ shots.