• 한국산학기술학회논문지
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• 제8권4호
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• pp.743-747
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• 2007

반도체 소자 제작에 있어서 회로의 pattern 형성에 이용하는 차세대 lithography 공정 기술을 위해서 전자빔 lithography 공정 기술 연구가 진행되고 있다. 본 연구에서는 Gauss 해석법과 Monte Carlo의 수치해석법을 사용하여 두께 100 nm의 PMMA (poly-methyl-methacrylate) resist에 전자 $1{\times}10^4$를 입사시키고, 입사 전자빔 에너지에 따른 PMMA 내에서의 투과 깊이를 비교하였다. 전자빔 에너지의 크기는 100eV, 300eV, 500eV, 700eV, 그리고 1000eV에 대하여 simulation을 실시하였다.

• 한국진공학회지
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• 제8권2호
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• pp.102-110
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• 1999

The LIGA X-ray exposure step was modelled into three inequalities, by assuming that the X-ray energy attenuated within a resist is deposited only in the localized range of the resist. From these inequalities, equations for the minimum and maximum exposure times required for a good quality microstructure were obtained. Also, an equation for the thickness of an X-ray mask absorber was obtained from the exposure requirement of threshold dose deposition. The calculation method of the synchrotron radiation power from a synchrotron radiation source was introduced and applied to an X-ray exposure step. A power from a synchrotron radiation source was introduced and applied to an X-ray exposure step/ A power function of photon energy, approximating the attenuation length of the representative LIGA resist, PMMA, and the mean photon energy of the XZ-rays incident upon an X-ray mask absorber were applied to the above mentioned equations. Consequently, the tendencies of the minimum and maximum exposure and with respect to mean photon energy and thick ness of PMMA was obtained. Additionally, the tendencies of the necessary thickness of PMMA and photon energy of the X-ray mask absorber with respect to thickness of PMMA and photon energy of the X-rays incident upon an X-ray mask absorber were examined. The minimum exposure time increases monotonically with increasing mean photon energy for the same total power density and is not a function of the thickness of resist. The minimum exposure time increases with increasing mean photon energy for the same total power density in the case of the general LIGA process, where the thickness of PMMA is thinner than the attenuation length of PMMA. Additionally, the minimum exposure time increases monotonically with increasing thickness of PMMA. The maximally exposable thickness of resist is proportional to the attenuation length of the resist at the mean photon energy with its proportional constant of ln $(Dd_m/D_{dv})$. The necessary thickness of a gold X-ray mask absorber due to absorption edges of gold, increases smoothly with increasing PMMA thickness ratio, and is independent of the total power density itself. The simplicity of the derived equations has made clearly understandable the X-ray exposure phenomenon and the correlation among the exposure times, the attenuation coefficient and the thickness of an X-ray mask absorber, the attenuation coefficient and the thickness of the resist, and the synchrotron radiation power density.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.343-348
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• 2007

Molecular dynamics study of thermal NIL (Nano Imprint Lithography) process is performed to examine stamp-resist interactions. A layered structure consists of Ni stamp, poly-(methylmethacrylate) thin film resist and Si substrate was constructed for isothermal ensemble simulations. Imposing confined periodicity to the layered unit-cell, sequential movement of stamp followed by NVT simulation was implemented in accordance with the real NIL process. Both vdW and electrostatic potentials were considered in all non-bond interactions and resultant interaction energy between stamp and PMMA resist was monitored during stamping and releasing procedures. As a result, the stamp-resist interaction energy shows repulsive and adhesive characteristics in indentation and release respectively and irregular atomic concentration near the patterned layer were observed. Also, the spring back and rearrangement of PMMA molecules were analyzed in releasing process.

• Journal of information and communication convergence engineering
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• 제13권1호
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• pp.56-61
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• 2015

The demand for high-aspect-ratio structures has been increasing in the field of semiconductors and other applications. Here, we present the commercially available negative-tone SU-8 as a potential resist that can be used for direct patterning of high-aspect-ratio structures at the submicron scale and the nanoscale. Such resist patterns can be used as polymeric molds to create high-aspect-ratio metallic submicron and nanoscale structures by using electroplating. Compared with poly (methyl methacrylate) (PMMA), we found that the negative tone resist required an exposure dose that was less than that of PMMA of equal thickness by a factor of 100-150. Patterning of up to 4:1 aspect ratio SU-8 structures with a minimum feature size of 500 nm was demonstrated. In addition, nanoimprint lithography was studied to further extend the aspect ratio to realize a minimum feature size of less than 10 nm with an extremely high aspect ratio in the negative resist.

• 전자공학회논문지A
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• 제31A권10호
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• pp.101-107
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• 1994

The PMMA/Ge/AZ trilayer resist decreased proximity effect of backscattering electrons and corrected pattern distoration in order to from deep submicron patterns. In the experiment, the prosiemity effect is decreased by 11% and 30% for the case of 0.9$\mu$m and 1.7$\mu$m AZ, respectively, in trilayer resist compared to monolyer resist. also, the EID of 240$\AA$ Ge film is smaller than that of 500$\AA$ film by 365. 0.1$\mu$m line/space was formed in the 2000$\AA$ PMMA layer with the condition of dose 330${\mu}C/cm^{2}$ and of 150sec of develop time in MIBK : IPA (1:3) developer.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권2호
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• pp.1119-1120
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• 2007

Nano-sized metal patterns were successfully fabricated on flexible PET substrate using nanoimprint lithography. 70nm line and space PMMA resist pattern was formed on PET substrate without residual layer by 'artial filling effect' and 20nm thin Cr metal layer was deposited by e-beam evaporation. Then, PMMA resist was selectively removed by acetone and 70nm narrow Cr pattern was formed.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2007년도 춘계학술발표회 초록집
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• pp.24-25
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• 2007

Nano-sized metal patterns were successfully fabricated on flexible PET substrate using nanoimprint lithography. 70nm line and space PMMA resist pattern was formed on PET substrate without residual layer by "partial filling effect' and 20nm thin Cr metal layer was deposited by e-beam evaporation. Then, PMMA resist was selectively removed by acetone and 70nm narrow Cr pattern was formed.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.733-736
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• 2000

In the first step of the LIGA process a resist layer, typically PMMA(polymethylmethacrylate), is pattered by deep X-ray lithography. Then the exposed parts are dissolved by an organic developer. To describe the developer. To describe the development course the parameters influencing the development process was investigated. The developed depth is proportional to the square root of the development time which suggests that the development rate increases with increasing dose value and temperature. So the development course can be described by a phenomenological equation.

• 소성∙가공
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• 제13권3호
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• pp.290-295
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• 2004

Mircolens and microlens V-groove are realized using a novel fabrication technology based on the exposure of a resist, usually PMMA, to deep X-rays and subsequent thermal treatment and inclined deep X-ray lithography, respectively. The fabrication technology is very simple and produces microlenses and microlens V-groove with good surface roughness of several nm. The molecular weight and glass transition temperature of PMMA is reduced when it is irradiated with deep X-rays. The microlenses were produced through the effects of volume change, surface tension, and reflow during thermal treatment of irradiated PMMA. Microlenses were produced with diameters ranging from 30 to $1500\mu\textrm{m}$. The surface X-ray mask is also fabricated to realize microlens arrays on PMMA sheet with a large area. The size of the micro V-groove is fabricated in the range of 12~$60\mu\textrm{m}$.

• 전자공학회논문지A
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• 제33A권7호
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• pp.198-204
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• 1996

Electron beam lithography is one of the importnat technologies which can delineate deep submicron patterns. REcently, electron beam lithography is being applied in delineating the critical layers of semiconductor device fabrication. In this paper, we present a development simulation program for electron beam lithography and study the development profiles of resist when resist is exposed by the electron beam. Experimentally, the development parameter of positive and negative resists are measured and the data is applied to input parameter of the simulation program. Also simulation results are compared of the process results in the view of resist profiles. As a result, for PMMA and SAL 601 resist, the trend of simulation to the values of process parameters agree with real process results very well, so that the process results can be predicted by the simulation.