• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.108-108
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• 2007

Inkjet printing is a non-contact and direct writing associated with a computer. In the industrial field, there have been many efforts to utilize the inkjet printing as a new way of manufacturing, especially for electronic devices. The etching resist used in this process is an organic polymer which becomes solidified when exposed to ultraviolet lights and has high viscosity of 300 cPs at ambient temperature. A piezoelectric-driven ink jet printhead is used to dispense $20-40\;{\mu}m$ diameter droplets onto the copper substrate to prevent subsequent etching. In this study, factors affecting the pattern formation such as printing resolution, jetting property, adhesion strength, etching and strip mechanism, UV pinning energy have been investigated. As a result, microscale Etch resist patterning of printed circuit board with tens of ${\mu}m$ high have been fabricated.

• Journal of the Korea Society of Computer and Information
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• v.9 no.1
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• pp.9-15
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• 2004

New WSW(Wrap Side Wall) is proposed to decrease junction electric field in this paper. WSW process is fabricated after first gate etch, followed NM1 ion implantation and deposition & etch nitride layer. New WSW structure has buffer layer to decrease electric field. Also we compared the hot carrier characteristics of WSW and conventional. Also, we design a test pattern including pulse generator, level shifter and frequency divider, so that we can evaluate AC hot carrier degradation on-chip. It came to light that the universality of the hot carrier degradation between DC and AC stress condition exists, which indicates that the device degradation comes from the same physical mechanism for both AC and DC stress. From this universality, AC lifetime under circuit operation condition can be estimated from DC hot carrier degradation characteristics.

• Proceedings of the KIEE Conference
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• 2003.10a
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• pp.322-325
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• 2003

BST thin films were etched with inductively coupled plasmas. A chemically assisted physical etch of BST was experimentally confirmed by ICP under various gas mixtures. After a 20 % addition of $BCl_3$ to the $Cl_2/Ar$ mixture, resulting in an increased the chemical effect. As a increases of RF power, substrate power, and substrate temperature, and decrease of working pressure, the ion energy flux and chlorine atoms density increased. The maximum etch rate of the BST thin films was 90.1 nm/min at the RF power, substrate power, working pressure, and substrate temperature were 700 W, 300 W, 1.6 Pa, and 20 $^{\circ}C$, respectively. It was proposed that sputter etching is dominant etching mechanism while the contribution of chemical reaction is relatively low due to low volatility of etching product.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.174-174
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• 2010

In this article, the dry etching mechanism of ZnO thin films in $N_2/Cl_2$/Ar gas chemistry was investigated. The ZnO thin films were deposited on Si substrate using Atomic layer deposition. The etching experiments were performed by inductively coupled plasma system. The maximum etch rate was104.5 nm/min and the highest selectivity of ZnO over $SiO_2$ was 3.3. Etching rate was measured by surface profiler. And the chemical reaction on the surface of the etched ZnO thin films was investigated by x-ray photo electrons pectroscopy. As a result of XPS, $Zn2p_{3/2}$ peak shifted toward a higher binding energy and the O-O and N-O bond were obtained from the sample of ZnO thin film which after plasma treatment.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.400-403
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• 2003

Etching characteristics of (Pb,Sr)$TiO_3$(PST) thin films were investigated using inductively coupled chlorine based plasma system as functions of gas mixing ratio, RF power and DC bias voltage. It was found that increasing of Ar content in gas mixture lead to sufficient increasing of etch rate and selectivity of PST to Pt. The maximum etch rate of PST film is $562\;{\AA}$/min and the selectivity of PST film to Pt is 0.8 at $Cl_2/(Cl_2+Ar)$ of 20 %. It was proposed that sputter etching is dominant etching mechanism while the contribution of chemical reaction is relatively low due to low volatility of etching products.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.5
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• pp.97-103
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• 2007

A novel selective metallization process to fabricate the fine conductive line based on inkjet printing has been investigated. Recently, Inkjet printing has been widely used in flat panel display, electronic circuits, biochips and bioMEMS because direct inkjet printing is an alternative and cost-effective technology for patterning and fabricating objects directly from design without masks. The photosensitive etching resist used in this process is an organic polymer which becomes solidified when exposed to ultraviolet lights and has high viscosity at ambient temperature. A piezoelectric-driven inkjet printhead is used to dispense 20-30 ${\mu}m$ diameter droplets onto the copper substrate to prevent subsequent etching. Repeatability of circuitry fabrication is closely related to the formation of steady droplets, adhesion between etching resist and copper substrate. Therefore, the ability to form small and stable droplets and surface topography of the copper surface and chemical attack must be taken into consideration for fine and precise patterns. In this study, factors affecting the pattern formation such as adhesion strength, etching mechanism, UV curing have been investigated. As a result, microscale copper patterns with tens of urn high have been fabricated.

• Transactions on Electrical and Electronic Materials
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• v.12 no.4
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• pp.144-147
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• 2011

In this work, we present a study regarding the etching characteristics on titanium nitride (TiN) thin films using an inductively coupled plasma system. The TiN thin film was etched using a $N_2/BCl_3$/Ar plasma. The studied etching parameters were the gas mixing ratio, the radio frequency (RF) power, the direct current (DC)-bias voltages, and the process pressures. The baseline conditions were as follows: RF power = 500 W, DC-bias voltage = -150 V, substrate temperature = $40^{\circ}C$, and process pressure = 15 mTorr. The maximum etch rate and the selectivity of the TiN to the $SiO_2$ thin film were 62.38 nm/min and 5.7, respectively. The X-ray photoelectron spectroscopy results showed no accumulation of etching byproducts from the etched surface of the TiN thin film. Based on the experimental results, the etched TiN thin film was obtained by the chemical etching found in the reactive ion etching mechanism.

• Journal of Information Display
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• v.12 no.1
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• pp.47-50
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• 2011

Highly stable amorphous indium.gallium.zinc-oxide (a-IGZO) thin-film transistors (TFTs) were fabricated with an etchstopper and via-hole structure. The TFTs exhibited 40 $cm^2$/V s field-effect mobility and a 0.21 V/dec gate voltage swing. Gate-bias stress induced a negligible threshold voltage shift (${\Delta}V_{th}$) at room temperature. The excellent stability is attribute to the via-hole and etch-stopper structure, in which, the source/drain metal contacts the active a-IGZO layer through two via holes (one on each side), resulting in minimized damage to the a-IGZO layer during the plasma etching of the source/drain metal. The comparison of the effects of the DC and AC stress on the performance of the TFTs at $60^{\circ}C$ showed that there was a smaller ${\Delta}V_{th}$ in the AC stress compared with the DC stress for the same effective stress time, indicating that the trappin of the carriers at the active layer-gate insulator interface was the dominant degradation mechanism.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05c
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• pp.182-185
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• 2003

Etching characteristics of (PB,Sr)$TiO_3$(PST) thin films Were investigated using inductively coupled chlorine based plasma system as functions of gas mixing ratio, RF power and DC bias voltage. It was found that increasing of Ar content in gas mixture' lead to sufficient increasing of etch rate and selectivity of PST to Pt. The maximum etch rate of PST film is 562 ${\AA}$/min and the selectivity of PST film to Pt is 0.8 at $Cl_2/(Cl_2+Ar)$ of 20 %. It was proposed that sputter etching is dominant etching mechanism while the contribution of chemical reaction is relatively low due to low volatility of etching products.

• Transactions on Electrical and Electronic Materials
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• v.13 no.3
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• pp.144-148
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• 2012

In this work, we investigated to the etching characteristics of $TiO_2$ thin film and the selectivity using the inductively coupled plasma system. The etch rate and the selectivity were obtained with various gas mixing ratios. The maximum etch rate of $TiO_2$ thin film was 61.6 nm/min. The selectivity of $TiO_2$ to TiN, and $TiO_2$ to $SiO_2$ were obtained as 2.13 and 1.39, respectively. The etching process conditions are 400 W for RF power, -150 V for DC-bias voltage, 2 Pa for the process pressure, and $40^{\circ}C$ for substrate temperature. The chemical states of the etched surfaces were investigated with X-ray photoelectron spectroscopy (XPS). Its analysis showed that the etching mechanism was based on the physical and chemical pathways in the ion-assisted physical reaction.