• Clean Technology
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• v.23 no.4
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• pp.357-363
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• 2017

In this study, the supercritical carbon dioxide ($scCO_2$)/ n-butyl acetate (n-BA) co-solvent system was employed to remove an unexposed negative photoresist (PR) from the surface of a silicon wafer. In addition, the selectivity of the $scCO_2$/n-BA co-solvent system was confirmed for the unexposed and exposed negative PR. Optimum conditions for removal of the unexposed PR were obtained from various conditions such as pressure, temperature and n-BA ratio. The n-BA was highly soluble in $scCO_2$ without cloud point and phase separation in mostly experimental conditions. However, the $scCO_2$/n-BA co-solvent was phase separated at 100 bar, above $80^{\circ}C$. The unexposed and exposed PR was swelled in $scCO_2$ solvent at all experimental conditions. The complete removal of unexposed PR was achieved from the reaction condition of 160 bar, 10 min, $40^{\circ}C$ and 75 wt% n-BA in $scCO_2$, as measured by ellipsometry. The exposed photoresist showed high stability in the $scCO_2$/n-BA co-solvent system, which indicated that the $scCO_2$/n-BA co-solvent system has high selectivity for the PR removal in photo lithograph process. The $scCO_2$/n-BA co-solvent system not only prevent swelling of exposed PR, but also provide efficient and powful performance to removal unexposed PR.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.22-23
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• 2006

A process for removal of photoresist(PR) m semiconductor manufacturing using water vapor with ozone is presented. For the realization of the ozone/vapor mixture process, high concentration ozone generator and process facilities have developed. As a result of the silicon wafer PR strip test, we confirmed the high efficiency PR strip rates of 400nm/mm or more at the ozone concentration of 16wt%/$O_2$. The ozone/vapor mixture process is more effective than the ozonized water Immersion process.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.11
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• pp.1143-1148
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• 2004

In this study, photoresist stripping in semiconductor or LCD (liquid crystal display) fabrication processes using DIO, was investigated. In order to obtain the high PR stripping efficiency of DIO. we have developed new ozone-generating system with high ozone concentration and ozone-resolving system with high contact ratio. In this study, we obtained ozone gas concentrations of 11 % by new ozone-generating system, ozone-resolving efficiency of 99.5 % and maximum solubility of 130 ppm in deionized water. We applied the newly designed equipments to photoresist stripping processes and obtained similar results to SPM(sulfuric-peroxide mixture) process characteristics.

• Korean Journal of Materials Research
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• v.28 no.4
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• pp.208-213
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• 2018

Epitaxial ($11{\bar{2}}0$) a-plane GaN films were grown on a ($1{\bar{1}}02$) R-plane sapphire substrate with photoresist (PR) masks using metal organic chemical vapor deposition (MOCVD). The PR mask with striped patterns was prepared using an ex-situ lithography process, whereas carbonization and heat treatment of the PR mask were carried out using an in-situ MOCVD. The heat treatment of the PR mask was continuously conducted in ambient $H_2/NH_3$ mixture gas at $1140^{\circ}C$ after carbonization by the pyrolysis in ambient $H_2$ at $1100^{\circ}C$. As the time of the heat treatment progressed, the striped patterns of the carbonized PR mask shrank. The heat treatment of the carbonized PR mask facilitated epitaxial lateral overgrowth (ELO) of a-plane GaN films without carbon contamination on the R-plane sapphire substrate. Thhe surface morphology of a-plane GaN films was investigated by scanning electron microscopy and atomic force microscopy. The structural characteristics of a-plane GaN films on an R-plane sapphire substrate were evaluated by ${\omega}-2{\theta}$ high-resolution X-ray diffraction. The a-plane GaN films were characterized by X-ray photoelectron spectroscopy (XPS) to determine carbon contamination from carbonized PR masks in the GaN film bulk. After $Ar^+$ ion etching, XPS spectra indicated that carbon contamination exists only in the surface region. Finally, the heat treatment of carbonized PR masks was used to grow high-quality a-plane GaN films without carbon contamination. This approach showed the promising potential of the ELO process by using a PR mask.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.4
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• pp.387-394
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• 2013

As the feature size of integrated circuits continues to decrease, the challenge of achieving an oxidation-free exposed layer after photoresist (PR) stripping is becoming a critical issue for semiconductor device fabrication. In this article, the hydrogen plasma characteristics in direct plasma and the PR stripping rate in remote plasma were studied using a $120{\Phi}$ cylindrical inductively coupled plasma source. E mode, H mode and E-H mode transitions were observed, which were defined by matching the $V_{rms}$ and total impedance. In addition, the dependence of the E-H mode transition on pressure was examined and the corresponding plasma instability regions were identified. The plasma density and electron temperature increased gradually under the same process conditions. In contrast, the PR stripping rate decreased with increasing proportion of $H_2$ gas in mixed $H_2/N_2$ plasma. The decrease in concentration of reactive radicals for the removal of PR with increasing $H_2$ gas flow rate suggests that NH radicals have a dominant effect as the main volatile product.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2006.05a
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• pp.172-176
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• 2006

본 논문에서는 물을 이용한 193nm immersion lithography에서 물이 photoresist(PR)에 흡수되는 현상을 측정하기 위하여 타원해석기(Ellipsometer)의 응용 가능성을 연구하였다. 물이 PR 에 흡수됨에 따라 swelling 현상이 발생하여 두께 증가로 나타났는데 이는 실시간 타원해석기를 적용하여 시간에 따른 두께 변화를 분석함으로써 그 반응정도를 분석해 낼 수 있었다. 또한 짧은 시간에 발생하는 물의 흡수 현상은 imaging 타원해석기론 이용하여 규명할 수가 있었다.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.6
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• pp.36-40
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• 2009

Development of maskless lithography techniques can provide a potential solution for the photomask cost issue. Furthermore, it could open a market for small scale manufacturing applications. Since femtosecond lasers have been found suitable for processing of a wide range of materials with sub-micrometer resolution, it is attractive to use this technique for maskless lithography. As a femtosecond laser has recently been developed, both of high power and high photon density are easily obtained. The high photon density results in photopolymerization of photoresist whose absorption spectrum is shorter than that of the femtosecond laser. The maskless lithography using the two-photon absorption (TPA) makes micro structures. In this paper, we present a femtosecond laser direct write lithography for submicron PR patterning, which show great potential for future application.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1500-1503
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• 2009

In this paper, we studied about atmospheric pressure remote plasma ashing of photoresist(PR), by using a modified dielectric barrier discharge(DBD). The effect of various gas combinations such as $N_2/O_2$, $N_2/O_2+SF_6$ on the changes PR ashing rate was investigated as a function of power. The maximum PR ashing rate of 1850 nm/min was achieved at $N_2$ (70 slm)/ $O_2$ (200 sccm) + $SF_6$ (3 slm). We found that as the oxygen and fluorine radical peaks were increased, the ashing rate is increased, too.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.1
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• pp.22-27
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• 2007

we have been studied on the realization of the boundary layer controlled ozone process and related facilities in order to apply for the photo-resist strip process in the semiconductor and flat panel display manufacturing. By means of developing the technology for the high concentration ozone production, it was possible to realized the boundary layer control ozone process by vapor. As a result of the silicon wafer PR strip test, we obtained the strip rate of about 400nm/min at the ozone concentration of 16wt% and flow rate of 8[liter/min.].

• Transactions on Electrical and Electronic Materials
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• v.15 no.3
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• pp.159-163
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• 2014

More accurate CD (Critical Dimension) control is required for the nanometer-scaled devices. However, since the reflectivity between substrate and PR (Photoresist) becomes higher, the CD (Critical Dimension) swing curve was intensified. The higher reflectivity also causes PR notching due to the pattern of sub-layer. For this device requirement, it was optimized for the thickness, refractive index(n) and absorption coefficient(k) in the bottom anti-reflective coating(BARC; SiON) and photoresist with the minimum reflectivity. The computational simulated conditions, which were determined with the thickness of 33 nm, n of 1.89 and k of 0.369 as the optimum condition, were successfully applied to the experiments with no standing wave for the 0.13um-device. At this condition, the lowest reflectivity was 0.44%. This optimum condition for BARC SiON film was applied to the process for 0.13um-device. The optimum SiON film as BARC to PR and sub-layer could be formed with the accurate CD control and no standing waver for the nanometer-scaled semiconductor manufacturing process.