• Polymer(Korea)
• /
• v.26 no.5
• /
• pp.634-643
• /
• 2002

Ultrathin film of polyamic acid having benzene and sulfonyloxyimide moieties was prepared using the Langmuir-Blodgett (LB) technique, and then photosensitive polyimide LB film was obtained by the thermal treatment of precursor polyamic acid multilayers at 200$\^{C}$ for 1 hr. The polyamic acid was synthesized by condensation polymerization under THF and pyridine cosolvent. All monomers and polymers were identified through elemental analysis, FT-IR and $^1$H-NMR spectroscopic measurements. The microarray patterning of photosensitive polyimide LB film on a gold substrate was generated with a deep UV lithography technique. The well-characterized monolayer of cytochrome c was immobilized on the microarray patterns using two different self-assembly processes. Physical and electrochemical properties of the self-assembled cytochrome c monolayer were investigated based on cyclic voltammetry and atomic force microscopy (AFM). Also, its application in bioelectronic device was examined.

• Applied Chemistry for Engineering
• /
• v.21 no.4
• /
• pp.411-416
• /
• 2010

In this research, we intended to improve the tolerance of thick film resistor using photosensitive polymer resistor paste which was fabricated with alkali-solution developable photosensitive resin and conductive carbon black. At first, we investigated the effect of the selection of carbon black and photosensitive resin on the resistance range and tolerance level of polymer thick film resistor (PTFR). And then, a difference in resistance tolerance was evaluated according to the coating methods of photosensitive resistor paste on test board. In case that the photosensitive resistor paste was coated on whole surface of test board using screen printing, large positional tolerance was obtained because the formation of the thick film with uniform thickness was difficult. On the other hand, when the paste was coated with roller, the resistive thick film with uniform thickness was formed on the whole board area and the result of resistance evaluation showed low tolerance in ${\pm}10%$ range. The tolerance of PTFR could be improved by combination of the precise patterning using photo-process and the coating process for the resistive thick film with uniform thickness.

• Proceedings of the Optical Society of Korea Conference
• /
• 2000.02a
• /
• pp.298-299
• /
• 2000

3차원 영상을 디스플레이하기 위한 반사형 광기록식 공간 광소자(Optically Addressed Spatial Light Modulator)를 연구하였다. 다시점 영상으로 표현되는 3차원 영상을 시분할 방식으로 디스플레이 하기 위해서는 고속의 프레임 구동이 가능한 디스플레이 소자가 있어야 하는데 본 연구에서는 Surface Stabilized Ferroelectric Liquid Crystal을 이용하여 그림 1과 같은 구조를 갖는 소자를 제작하였다.$^{(1)}$ 입력상이 입사되는 방향에 1.1 미리 미터 정도의 ITO 유리 기판이 있으며 투명 전극 다음에 약 2마이크론 정도의 비결정질 구조를 갖는 Si:H 감광층이 있다. 반사형 구조를 위해서 반사경으로 알루미늄 층을 10마이크론 X 10 마이크론 크기의 미소 패턴으로 화소화하였으며 강유전성 액정 결정을 Surface Stabilized화하기 위해서 배양막과 2 마이크론 이하의 Spacer를 두었다. 일반적인 액정 소자와 같이 다시 배양막과 유리 기판을 갖게 하였다. (중략)

• Journal of Sensor Science and Technology
• /
• v.8 no.1
• /
• pp.32-37
• /
• 1999

A capacitance-type humidity sensor with mesa structure in which porous silicon layer is used as humidity-sensing material is developed and its humidity sensing properties are measured. This sensor has a structure where two electrodes are set on the up-side of the wafer against the past typical structure having these electrodes on the up and down-side of the wafer. Therefore, the sensor can be fabricated monolithically to be more compatible with the IC process technology, and is possible to detect more correct output capacitance by removing the effect of the parasitic capacitance from the bottom layer and other junctions. To do this, the sensor was fabricated using process such as localized formation of porous silicon, oxidation of porous silicon layer, and etching of oxidized porous silicon layer. From the completed samples, the dependence of capacitance on the relative humidity of 55 to 90% more was measured at room temperature. As the result, the measured capacitance increased monotonously higher at the low frequency of 120 Hz, where the capacitance was observed to increase over 300%.

• Journal of Sensor Science and Technology
• /
• v.8 no.5
• /
• pp.394-399
• /
• 1999

An automobile hot-film air flow sensor is deposited with platinum by sputtering method, patterned by photoresisted lift-off method, annealed in $1,000^{\circ}C$ and passivated with PI-2723. The TCR of the fabricated hot-film is about $3500\;ppm/^{\circ}C$. In the experiment, the output voltage of the sensor is in proportional to the fourth power root in the air mass flow range of 300 kg/h. The error in the full flow range is about ${\pm}0.7%$. In the range of air temperature of $-20^{\circ}C{\sim}120^{\circ}C$, the error is about ${\pm}1%$ that is ${\pm}2%$ lower than that of the reference sensor. Therefore, the fabricated hot-film air flow sensor satisfies the specification for automobile. Lower temperature error of the sensor provides to control the precise air/fuel ratio of automobile engine and results in improvement of a fuel mileage and the less amount of toxic gases emitted by automobile.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.4
• /
• pp.1993-1998
• /
• 2011

Semiconductor industry needs to have fine patterns in order to fabricate the high density integrated circuit. For nano-scale patterns, hard-mask is used to multi-layer structure which is formed by CVD (chemical vaporized deposition) process. In this work, we prepared single-layer hard-mask by using organic-inorganic hybrid polymer for spin-on process. The inorganic part of hard-mask was much easier etching than photo resist layer. Beside, the organic part of hard-mask was much harder etching than substrate layer. We characterized the optical and morphological properties to the hard mask films using organic-inorganic hybrid polymer, and then etch rate of photo resist layer and hard-mask film were compared. The hybrid polymer prepared from organic and inorganic materials was found to be useful hard-mask film to form the nano-patterns.

• Journal of the Korean Institute of Telematics and Electronics D
• /
• v.35D no.9
• /
• pp.42-47
• /
• 1998

We have fabricated electron-optical lens for micro E-beam system that can overcome the limitation of current E-beam lithography. Our electron-optical lens consists of multiple silicon electrodes which were fabricated by micromachining technology and assembled by anodic bonding. The assembled system was installed in UHV chamber to observe the emission characteristics of focused electrons by the electro-optical lens. We used STM(Scanning Tunneling Microscope) tip for electron source. By performing lithography with the focused electrons with PMMA(poly-methylmethacrylate) as E-beam resist. We could draw 0.13${\mu}{\textrm}{m}$ nano-scale lines.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.23 no.5
• /
• pp.353-357
• /
• 2010

Recently, silicon etching have received much attention for display industry, nano imprint technology, silicon photonics, and MEMS application. After the etching process, removing of etch mask and residue of sidewall is very important. The investigation of the etched mask removing was carried out by using the ashing, HF dipping and acid cleaning process. Experiment shows that oxygen component of reactive gas and photoresist react with silicon and converting them into the mask fence. It is very difficult to remove by using ashing or acid cleaning process because mask fence consisted of Si and O compounds. However, dilute HF dipping is very effective process for SiOx layer removing. Finally, we found optimized condition for etched mask removing.

• KSBB Journal
• /
• v.14 no.6
• /
• pp.643-650
• /
• 1999

An artificial photoreceptor composed of bacteriorhodopsin(bR)/flavin complex Langmuir-Blodgett(LB) films was developed by mimicking the human visual system. bR and flavin molecules were deposited onto solid substrate by LB technique, and the deposition of two molecules was proved by UV/VIS absorption spectroscopy and atomic force microscopy(AFM). Based on AFM images and photocurrent generation from the LB films, the optimal conditions for device fabrication were determined. With a series of light illuminations, the generated photocurrent could be detected, and the response characteristics of two molecules could be clearly distinguished from each other. According to the obtained signal shapes, three distinctive regions could be found in the obtained action spectrum. Using a correlation between the photocurrent generation and the wavelength of the input light, it was possible to organize the basic rules to interpret the wavelength of the input light. It is concluded that the proposed artificial photoreceptor would e applicable to the bioelectronic device for color recognition.

• Journal of Sensor Science and Technology
• /
• v.5 no.1
• /
• pp.15-22
• /
• 1996

FET type $Ca^{2+}$ sensor(Ca-ISFET) was fabricated by micropool and photolithographic method utilizing photosensitive polymer as membrane materials. When OMR-83 negative photoresist was used as membrane material, it gave good sensitivity by micropool method with dioctyladipate as plasticizer but it could not be used in the photolithographic method. When poly(viny1 butyral), PVB was used as membrane material, it gave relatively high sensitivity ($23{\pm}0.2\;mV/decade$) for $Ca^{2+}$ concentration range of $10^{-4}{\sim}10^{-1}\;mole/{\ell}$ by photolithographic method. PVB also provided good adhesion to the pH-ISFET base device without adhesion promoter pretreatment and any plasticizer.