• Korean Journal of Materials Research
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• v.6 no.11
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• pp.1127-1135
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• 1996

반도체 소자가 고집적화 됨에 따라 단위공정의 수가 증가하게 되었고 동시에 실리콘 기판의 오염에 대한 문제가 증가하였다. 실리콘 기판의 주 오염물로는 유기물, 파티클, 금속분순물 등이 있으며 특히, Cu와 Fe과 같은 금속불순물은 이온주입 공정, reactive ion etching, photoresist ashing과 같은 실 공정 중에 1011-1013atoms/㎤정도로 오염이 되고 있다. 그러나 금속불순물 중 Cu와 같은 전기음성도가 실리콘 보다 큰 오염물질은 일반적인 습석세정방법으로는 제거하기 힘들다. 따라서 본 연구에서는 Cu와 Fe과 같은 금속불순물을 제거할 목적을 건식과 습식 세정방법을 혼합한 UV/ozone과 HF세정을 제안하여 실시하였다. CuCI2와 FeCI2 표준용액으로 실리콘 기판을 인위적 오염한 후 split 1(HF-only), split 2 (UV/ozone+HF), split 3 (UV/ozone + HF 2번 반복), split 4(UV/ozone-HF 3번 반복)를 실시하였고 TXRF(Total Reflection X-Ray Fluorescence)와 AFM(Atomic Force Microscope)으로 금속불순물 제거량과 표면거칠기를 각각 측정하였다. 또한 contact angle 측정으로 세정에 따른 표면상태도 측정하였다. TXRF 측정결과 split 4가 가장 적은 양의 금속불순물 잔류량을 보였으며 AFM 분석을 통한 표면거칠기도 가장 작은 RMS 값을 나타내었다. Contact angle 측정 결과 UV/ozone 처리는 친수성 표면을 형성하였고 HF처리는 소수성 표면을 형성하였다.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.22 no.1
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• pp.52-59
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• 2012

Objectives: The purpose of this study was to evaluate the exposure possibility of by-products during the semiconductor manufacturing processes. Methods: The authors investigated types of chemicals generated during semiconductor manufacturing processes by the qualitative experiment on generation of by-products at the laboratory and a literature survey. Results: By-products due to decomposition of photoresist by UV-light during the photo-lithography process, ionization of arsine during the ion implant process, and inter-reactions of chemicals used at diffusion and deposition processes can be generated in wafer fabrication line. Volatile organic compounds (VOCs) such as benzene and formaldehyde can be generated during the mold process due to decomposition of epoxy molding compound and mold cleaner in semiconductor chip assembly line. Conclusions: Various types of by-products can be generated during the semiconductor manufacturing processes. Therefore, by-products carcinogen such as benzene, formaldehyde, and arsenic as well as chemical substances used during the semiconductor manufacturing processes should be controlled carefully.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.698-701
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• 2005

We have investigated experimentally a nano patterning using electron beam lithography for the nickel stamper fabrication. Recently, DVD and Blu-ray disk(BD) have nano-scale patterns in order to increase the storage density. Specially, BD has 100nm-scale patterns which are generally fabricated by electron beam lithography. In this paper, we found optimum condition of electron-beam lithography for 100nm-scale patterning. We controlled various conditions of EHP(acceleration voltage), beam current, dose and aperture size in order to obtain optimum conditions. We used 100nm-thick PMMA layer on a silicon wafer as photoresist. We found that EHP was the most dominant factor in electron-beam lithography.

• Laser Solutions
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• v.11 no.2
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• pp.26-32
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• 2008

Micro lens array (MLA) is widely used in information technology (IT) industry fields, for examples such as a projection display, an optical power regulator, a micro mass spectrometer and for medical appliances. Recently, MLA have been fabricated and developed by using a reflow method, micro etching, electroplating, micromachining and laser local heating. Laser local thermal-expansion (LLTE) technology demonstrates the formation of microdots on the surface of polymer substrate, in this paper. We have also investigated the new direct fabrication method of placing the MLA on the surface of a SU-8 photoresist layer. We have obtained the 3D shape of the micro lens processed by UV laser irradiation and have experimentally verified the optimal process conditions.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.65-65
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• 2010

Extreme ultraviolet lithography (EUVL) is expected to be applied for making patterns below 32 nm in device industry. An ultrathin EUV photoresist (PR) of a few nm in thickness is required to reduce minimum feature size further. Here, we show that pentacene molecular layers can be employed as a new EUV resist for the first time. Dots and lines in nm scale are successfully realized using the new molecular resist. We clearly provide the mechanism for forming the nanopatterns with scanning photoemission microscope (SPEM), EUV interference lithography (EUV-IL), atomic force microscope (AFM), photoemission spectroscopy (PES), etc. The molecular PR has several advantages over traditional polymer EUV PRs; for example, high thermal/chemical stability, negligible outgassing, ability to control the height and width on the nanometer scale, leaving fewer residuals, no need for a chemical development process and thus reduction of chemical waste to make the nanopatterns. Besides, it could be applied to any substrate to which pentacene bonds chemically, such as $SiO_2$, SiN, and SiON, which is of importance in the device industry.

• Journal of the Korean Magnetics Society
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• v.17 no.3
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• pp.137-140
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• 2007

The ordering of nanopores in AAO has been improved by using laser interference lithography. After growing Fe and Cu on this substrate in vacuum and removing AAO, Fe nanodots are fabricated. The nanopores in AAO and nanodots are ordered in one dimension following the prepatterning. It has been confirmed from the magnetic hysteresis loop that the Fe nanodots have vortex structure and the dipolar interaction is dominant among them.

• Journal of the Optical Society of Korea
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• v.17 no.6
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• pp.513-517
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• 2013

Recently, maskless lithography (ML) systems have become popular in digital manufacturing technologies. To achieve high-throughput manufacturing processes, digital micromirror devices (DMD) in ML systems must be driven to their operational limits, often in harsh conditions. We propose an instrument and algorithm to detect DMD malfunctions to ensure perfect mask image transfer to the photoresist in ML systems. DMD malfunctions are caused by either bad DMD pixels or data transfer errors. We detect bad DMD pixels with $20{\times}20$ pixel by white and black image tests. To analyze data transfer errors at high frame rates, we monitor changes in the frame rate of a target DMD pixel driven by the input data with a set frame rate of up to 28000 frames per second (fps). For our data transfer error detection method, we verified that there are no data transfer errors in the test by confirming the agreement between the input frame rate and the output frame rate within the measurement accuracy of 1 fps.

• Safety and Health at Work
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• v.12 no.3
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• pp.403-415
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• 2021

Background: This study aimed to assess the possibility of benzene exposure in workers of a Korean semiconductor manufacturing company by reviewing the issued patents. Methods: A systematic patent search was conducted with the Google "Advanced Patent Search" engine using the keywords "semiconductor" and "benzene" combined with all of the words accessed on January 24, 2016. Results: As a result of the search, we reviewed 75 patent documents filed by a Korean semiconductor manufacturing company from 1994 to 2010. From 22 patents, we found that benzene could have been used as one of the carbon sources in chemical vapor deposition for capacitor; as diamond-like carbon for solar cell, graphene formation, or etching for transition metal thin film; and as a solvent for dielectric film, silicon oxide layer, nanomaterials, photoresist, rise for immersion lithography, electrophotography, and quantum dot ink. Conclusion: Considering the date of patent filing, it is possible that workers in the chemical vapor deposition, immersion lithography, and graphene formation processes could be exposed to benzene from 1996 to 2010.

• Journal of Sensor Science and Technology
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• v.28 no.4
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• pp.251-255
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• 2019

We propose a two-step lithography process to minimize edge-bead issues caused by thick photoresist (PR) coating. In the conventional PR process, the edge bead can be efficiently removed by applying an edge-bead removal (EBR) process while rotating the silicon wafer at a high speed. However, applying conventional EBR to the production of desired PR mold with unique negative patterns cannot be used because a lower rpm of spin coating and a lower temperature in the soft bake process are required. To overcome this problem, a two-step lithography process was developed in this study and applied to the fabrication of a polydimethylsiloxane (PDMS) film having super-hydrophobic characteristics. Following UV exposure with a first photomask, the exposed part of the silicon wafer was selectively removed by applying a PR developer while rotating at a low rpm. Then, unique PR mold structures were prepared by employing an additional under-exposure process with a second mask, and the mold patterns were transferred to the PDMS. Results showed that the fabricated PDMS film based on the two-step lithography process reduced the height difference from 23% to 5%. In addition, the water contact angle was greatly improved by spraying of hydrophobic nanosilica on the dual-scaled PDMS surface.

• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.569-572
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• 1998

The semiconductor technology for the deep submicron $regime(0.18\mu\textrm{m})$ and larger wafer $diameters(300\mu\textrm{m})$ has been increased its cost with each wafer. Hence, in order to reduce the number of characterization experiments of a new process, lithographic modeling is more important than it was. In this paper, we introduced a new method to extract Dill ABC parameters from the refractive index changes. In order to evaluate our exact method, results of experiments and calculations for several resists were compared with other methods〔1〕through the lithographic simulation.