• 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 Crystal Growth and Crystal Technology
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• v.9 no.1
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• pp.60-63
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• 1999

Application of reactive ion etching (RIE) technique to Ta-Al alloy thin film with a thickness of $1000{\AA}$ was studied. $CF_{4}$ gas could be used effectively to etch the Ta-Al alloy thin film. The etching rate in the thin film with Ta content of 50 mol% was about $67{\AA}/min$. NO selectivity between the Ta-Al alloy film and $SiO_{2}$ film was observed during the etching using the $CF_{4}$ gas. The etching rate of the $SiO_{2}$ layer was 12 times faster than that of the Ta-Al alloy thin film. It was also observed that photoresist of AZ5214 was more useful than Shiepley 1400-27 in RIE with the $CF_{4}$ gas.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1998.09a
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• pp.85-90
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• 1998

Reactive ion etching (RIE) of Ta-Al alloy thin film and SiO2 thin films was observed during the etching with the CF4 gas and the could be used effectively to etch the Ta-Al alloy thin film. The etching rate of the thin film at a Ta content of 50 mol% was about 67$\AA$/min. No selectivity between the Ta-Al alloy thin film and SiO2 thin films was observed during the etching with the CF4 gas and the etching rate of the SiO2 layer was 12 times faster than that of the Ta-Al alloy thin film. In addition, it was observed that photoresist of AZ5214 was more useful than Shiepley 1400-2 in RIE with the CF4 gas.

• Laser Solutions
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• v.10 no.2
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• pp.5-15
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• 2007

A new printing process for LCD color filter is proposed in this work by using the localized laser heating, which is called laser-induced spray printing (LISP) process. The LISP is a non-contact process, which injects the ink from the donor substrate to the glass substrate by the bubble pressure induced by laser heating. The temperature distribution of the donor substrate is calculated numerically to explain the ink ejection phenomena. The composition of the ink was includes the red pigment, n-butanol, xylene, BCA and epoxy. Experiments were conducted by using the fiber laser system, and the color filter patterns were deposited successfully under the proper laser heating conditions.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.2
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• pp.140-148
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• 2000

In this paper, using surface micromachining technology with thick photoresist and aluminum, an SLM(Spatial Light Modulator), which is applied to the fields of adaptive optics and pattern recognition system, was fabricated and the electromechanical properties of the fabricated micro SLM are measured. In order to maximize fill-factor and remove mechanical coupling between micro SLM actuators, the micro SLM is composed of three aluminum layers so that spring structure and upper electrode are placed beneath the mirror plate, and $10\times10$ each mirror plate is individually actuated. Also, the micro SLM was designed to be able to modulate phase and amplitude of incoming light in order to have a continuity of phase modulation of incoming light. In the case of amplitude and phase modulation, maximum vertical displacement is 4$\mum$, and maximum angular displacement is $\pm4.6^{\corc}$ respectively. The height difference of the fabricated mirror plate was able to be reduced to 1100A with mirror plate planarization method using negative photoresist(AZ5214). The electromechanical properties of the fabricated micro SLM were measured with the optical measurement system using He-Ne laser and PSD(position sensitive device).

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.84-84
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• 2010

In this study, we report on the novel lithographic patterning method to fabricate organic-semiconductor devices based on photo and e-beam lithography with well-known silicon technology. The method is applied to fabricate pentacene-based organic field effect transistors. Owing to their solubility, sub-micron sized patterning of P3HT and PEDOT has been well established via micromolding in capillaries (MIMIC) and inkjet printing techniques. Since the thermally deposited pentacene cannot be dissolved in solvents, other approach was done to fabricate pentacene FETs with a very short channel length (~30nm), or in-plane orientation of pentacene molecules by using nanometer-scale periodic groove patterns as an alignment layer for high-performance pentacene devices. Here, we introduce the atomic layer deposition of $Al_2O_3$ film on pentacene as a passivation layer. $Al_2O_3$ passivation layer on OTFTs has some advantages in preventing the penetration of water and oxygen and obtaining the long-term stability of electrical properties. AZ5214 and ma N-2402 were used as a photo and e-beam resist, respectively. A few micrometer sized lithography patterns were transferred by wet and dry etching processes. Finally, we fabricated sub-micron sized pentacene FETs and measured their electrical characteristics.

• Journal of the Korean Vacuum Society
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• v.20 no.1
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• pp.63-69
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• 2011

In this study, we report on the novel lithographic patterning method to fabricate organic thin film field effect transistors (OTFTs) based on photo and e-beam lithography with well-known silicon technology. The method is applied to fabricate pentacene-based organic field effect transistors. Owing to their solubility, sub-micron sized patterning of P3HT and PEDOT has been well established via micromolding in capillaries and inkjet printing techniques. Since the thermally deposited pentacene cannot be dissolved in solvents, other approach was done to fabricate pentacene FETs with a very short channel length (~30 nm), or in-plane orientation of pentacene molecules by using nanometer-scale periodic groove patterns as an alignment layer for high-performance pentacene devices. Here, we introduce $Al_2O_3$ film grown via atomic layer deposition method onto pentacene as a passivation layer. $Al_2O_3$ passivation layer on OTFTs has some advantages in preventing the penetration of water and oxygen and obtaining the long-term stability of electrical properties. AZ5214 and ma N-2402 were used as a photo and e-beam resist, respectively. A few micrometer sized lithography patterns were transferred by wet and dry etching processes. Finally, we fabricated micron sized pentacene FETs and measured their electrical characteristics.