• Proceedings of the KIEE Conference
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• 1987.11a
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• pp.197-199
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• 1987

This paper is investigated on characteristics of photoresist using inorganic a-$Se_{75}Ge_{25}$. The sensitivity of negative photoresist showing insolubility against alkalie solution, with Ag-photodoped, is more prominent than that of positive photoresist used with only a-$Se_{75}Ge_{25}$. It is also showed that the contrast of negative photoresist, ${\gamma}=2.9$, is more prominent than that of positive photoresist, ${\gamma}=1.4$.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.274.2-274.2
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• 2013

We described a simple and efficient fabrication method for generating microfluidic channels with a circular-cross sectional geometry by exploiting the reflow phenomenon of a thick positive photoresist. Initial rectangular shaped positive photoresist micropatterns on a silicon wafer, which were fabricated by a conventional photolithography process, were converted into a half-circular shape by tuning the temperature to around $105^{\circ}C$. Through optimization of the reflow conditions, we could obtain a perfect circular micropattern of the positive photoresist, and control the diameter in a range from 100 to 400 ${\mu}m$. The resultant convex half-circular photoresist was used as a template for fabricating a concave polydimethylsiloxane (PDMS) through a replica molding process, and a circular PDMS microchannel was produced by bonding two half-circular PDMS layers. A variety of channel dimensions and patterns can be easily prepared, including straight, S-curve, X-, Y-, and T-shapes to mimic an in vivo vascular network. To inform an endothelial cell layer, we cultured primary human umbilical vein endothelial cells (HUVECs) inside circular PDMS microchannels, and demonstrated successful cell adhesion, proliferation, and alignment along the channel.

• Journal of the Semiconductor & Display Technology
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• v.6 no.3
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• pp.25-33
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• 2007

A computationally efficient and accurate Monte Carlo (MC) simulator of electron beam lithography process, which is named SCNU-EBL, has been developed for semiconductor nanometer pattern design and fabrication. The simulator is composed of a MC simulation model of electron trajectory into solid targets, an Gaussian-beam exposure simulation model, and a development simulation model of photoresist using a string model. Especially for the trajectories of incident electrons into the solid targets, the inner-shell electron scattering of an target atom and its discrete energy loss with an incident electron is efficiently modeled for multi-layer resists and heterogeneous multi-layer targets. The simulator was newly applied to the development profile simulation of ZEP520 positive photoresist for NGL(Next-Generation Lithography). The simulation of ZEP520 for electron-beam nanolithography gave a reasonable agreement with the SEM experiments of ZEP520 photoresist.

• Electrical & Electronic Materials
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• v.9 no.1
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• pp.59-66
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• 1996

Polyimides containing cyclobutane ring in main chain is known to be thermally stable and able to be developed in organic solvents after photolysis with 254 nm UV light. This type of polyimides can be used as promising positive photoresist in VLSI fabrication process. In the current VLSI process, photoresist films are formed by spin coating. The film thickness is more than several hundred nano meters. It seems that there is room for improvement of film coating process by introducing Langmuir Blodgett technique. Thereby ultra thin film photoresist can be formed, and higher density of integration in VLSI be achieved. In the present work, depositing procedure of LB films of this polyimide was investigated. LB film thickness was measured by ellipsometry to evaluate deposited film status. Chemical imidization procedure was studied to avoid several problems in thermal imidization. The pattern of submicron dimension has successfully formed on LB film of 8nm thick, which found showing good contrast.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.564-566
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• 2007

Synthesis of two photoactive compounds containing core imide moiety was carried out for an application to interdielectric layer in TFTLCD array. An aqueous alkaline developable polymer matrix was synthesized by free radical copolymerization. A positive photoresist formulation was developed utilizing synthesized UV monomers, photoactive compound, binder polymer, sulfactant and alkali developable polymer matrix. It was found that via-holes with good resolution, high transmittance and thermal resistance could be obtained by photolithographic process utilizing the new positive interdielectric material with high thermal stability.

• Journal of the Korean Applied Science and Technology
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• v.15 no.1
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• pp.25-33
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• 1998

Photoresist is defined as substance that makes chemical changes in its solubility, colouring and hardening by light energy. In this study, photosensitive photoresists of the positive type for a printing plate were studied. PF, o-, m-, p-CF resins as a matrix resin were synthesized at an identical condition. Photoresists were prepared by mixing NDS derivatives with a matrix resin at various mixing ratios. Characteristics of photoresists were studied by yield method of residual using solubility and Optical microscope was also analyzed. Prepared photoresist using NDS derivatives shows excellent photosensitivity and solubility compared with commercial product. The mixing ratio of 1:4(by mass) of NDS derivative[III] and m-CF resin shows the highest dissoultion rate among others. In addition, photoresist was obtained at this condition resulted in the superior sensitivity and contrast.

• Laser Solutions
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• v.10 no.2
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• pp.17-24
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• 2007

We have studied a laser direct writing lithography(LDWL). This is more important to apply to micro patterning using UV laser. We demonstrate the possibility of LDWL and construct the fabrication system. We use Galvano scanner to process quickly micro patterns from computer data. And laser beam is focused with $F-{\theta}$ lens. AZ5214 and SU-8 photoresist are chosen as experimental materials and a kind of well-known positive and negative photoresist respectively. Laser ablation mechanism depends on the optical properties of polymer. In this paper, therefore we investigate the phenomenon of laser ablation according to the laser fluence variation and measure the shape profile of micro patterned holes. From these experimental results, we show that LDWL is very useful to process various micro patterns directly.

• Journal of the Korean Graphic Arts Communication Society
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• v.20 no.2
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• pp.131-140
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• 2002

Chemically amplified deep UV(CA-DUV) resists are typically based on a combination of an acid labile polymer and a photoacid generator(PAG) but acid amplification type photoresist is formulated by addition of the acid amplifiers to chemically amplified resist system(CAPs). We developed acid amplifiers base on cyclohexanediol such as 1-methacryloyloxy-4-tosyloxy cyclohexane(MTC) and poly(MTC$_{10}$-co-tBMA$_{90}$)(P-1) to enhance photosensitivity. P-1 is a copolymer of tert-butyl methacrylate and MTC as a positive working photoresist based on polymeric acid amplifier in order to enhance photosensitivity and simplify the process of fomulating a photoresist. P-1 exhibited 2X higher photosensitivity compared with PtBMA. The acid amplifiers showed reasonable thermal stability for resist processing temperature and higher photosensitivity compared with chemically amplified resist.

• Bulletin of the Korean Chemical Society
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• v.29 no.9
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• pp.1689-1694
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• 2008

• Laser Solutions
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• v.14 no.1
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• pp.25-29
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• 2011

Micromachining of photosensitive glass by UV exposure, heat treatment, and etching processes is reported. Like photoresist, the photosensitive glass is also classified into positive and negative types by development characteristics. For the positive type, the exposed area is crystallized and etched away during the etching process in HF solution, whereas the unexposed area is crystallized and etched away for the negative type. The crystallized area of the photosensitive glass has an etch rate approximately 30~100 times faster than that of the amorphous area so that it becomes possible to fabricate microstructures in the glass. Based on the unique properties of glass such as high optical transparency, electrical insulation, and chemical/thermal stability, the glass micromachining technique introduced in this work could be widely applied to various devices in the fields of electronics, bio engineering, nanoelectonics and so on.