• JSTS:Journal of Semiconductor Technology and Science
• /
• v.8 no.2
• /
• pp.121-127
• /
• 2008

This paper presents design and fabrication of optimized geometry structure of electrostatic inkjet head. In order to verify effect of geometry shape, we simulate electric field intensity according to the head structure. The electric field strength increases linearly with increasing height of the micro nozzle. As the nozzle diameter decreases, the electric field along the periphery of the meniscus can be more concentrated. We design and fabricate the electrostatic inkjet heads, hole type and pole type, with optimized structure. It was fabricated using thick-thermal oxidation and silicon micromachining technique such as the deep reactive ion etching (DRIE) and chemical wet etching process. It is verified experimentally that the use of the MEMS inkjet head allows a stable and sustainable micro-dripping mode of droplet ejection. A stable micro dripping mode of ejection is observed under the voltages 2.5 kV and droplet diameter is $10\;{\mu}m$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2006.04a
• /
• pp.49-51
• /
• 2006

OLEOs was fabricated by PLD method. Wet etching process and plasma treatment of ITO on the glass were performed to extend the lifetime of the OLED and increase its brightness. The NPB, $Alq_3$, Li-Benzoate and AI layers on ITO pattern on the glass were deposited by PLO method, sequentially. When the etched ITO was treated by $O_2$ plasma with RF power of 50W, the best result was obtained. The lifetime of the OLED treated by $O_2$ plasma was extended from 3,770sec to 12,586sec compared to that without the plasma treatment.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.08a
• /
• pp.90.2-90.2
• /
• 2013

Vertically-aligned silicon nanostructure arrays (SNAs) have been drawing much attention due to their useful electrical properties, large surface area, and quantum confinement effect. SNAs are typically fabricated by chemical vapor deposition, reactive ion etching, or wet chemical etching. Recently, metal-assisted chemical etching process, which is relatively simple and cost-effective, in combination with nanosphere lithography was recently demonstrated for vertical SNA fabrication with controlled SNA diameters, lengths, and densities. However, this method exhibits limitations in terms of large-area preparation of unperiodic nanostructures and SNA geometry tuning independent of inter-structure separation. In this work, we introduced the layerby- layer deposition of polyelectrolytes for holding uniformly dispersed polystyrene beads as mask and demonstrated the fabrication of well-dispersed vertical SNAs with controlled geometric parameters on large substrates. Additionally, we present a new means of building in vitro neuronal networks using vertical nanowire arrays. Primary culture of rat hippocampal neurons were deposited on the bare and conducting polymer-coated SNAs and maintained for several weeks while their viability remains for several weeks. Combined with the recently-developed transfection method via nanowire internalization, the patterned vertical nanostructures will contribute to understanding how synaptic connectivity and site-specific perturbation will affect global neuronal network function in an extant in vitro neuronal circuit.

• Journal of Information Display
• /
• v.13 no.2
• /
• pp.61-66
• /
• 2012

The double-layered Ti/Si barrier metal is demonstrated for the source/drain Cu interconnections in oxide semiconductor thin-film transistors (TFTs). The transmission electromicroscopy and ion mass spectroscopy analyses revealed that the double-layered barrier structure suppresses the interfacial reaction and the interdiffusion at the interface after thermal annealing at $350^{\circ}C$. The underlying Si layer was found to be very useful for the etch stopper during wet etching for the Cu/Ti layers. The oxide TFTs with a double-layered Ti/Si barrier metal possess excellent TFT characteristics. It is concluded that the present barrier structure facilitates the back-channel-etch-type TFT process in the mass production line, where the four- or five-mask process is used.

• Journal of the Korean Vacuum Society
• /
• v.20 no.3
• /
• pp.217-224
• /
• 2011

of materials and simplification of process. Micro-blasting is one of the promising method for recycling of waste wafer due to their simple and low cost process. Therefore, in this paper, we make recycling wafer through the micro-blaster. A surface etched by micro-blaster forms particles, cracks and pyramid structure. A pyramid structure formed by micro-blaster has a advantage of reflectivity decrease. However, lifetime of minority carrier is decreased by particles and cracks. In order to solve this problems, we carried out the DRE(Damage Romove Etching). There are two ways to DRE process ; wet etching, dry etching. After the DRE process, we measured reflectivity and lifetime of minority carrier. Through these results, we confirmed that a wafer recycled can be used in solar cell.

• Korean Journal of Optics and Photonics
• /
• v.17 no.5
• /
• pp.437-446
• /
• 2006

A fabrication method fur high-aspect-ratio microchannels in stainless steel using laser-assisted thermochemical wet etching is reported in this paper. The fabrication of deep microchannels with an aspect ratio over ten is realized by applying a multiple etching process with an optimization of process conditions. The cross-sectional profile of the microchannels can be adjusted between rectangular and triangular shapes by properly controlling laser power and etchant concentration. Excellent dimensional uniformity is achieved among the channels with little heat-affected area. Microchannels with a width ranging from 15 to $50{\mu}m$ can be fabricated with an aspect ratio of ten and a pitch of 150 m or smaller. The effects of process variables such as laser power, scan speed, and etchant concentration on the fabrication results, including etch width, depth, and cross-sectional profile are closely examined.

• Journal of the Korean Society of Urban Environment
• /
• v.18 no.4
• /
• pp.503-509
• /
• 2018

In this study, a Proton-Transfer Reaction-Time-of-Flight Mass spectrometer (PTR-TOF-MS) was used for the continuous monitoring of Volatile Organic Compounds (VOCs) emitted from semiconductor workplace such as photolithography (PHOTO), flat panel display (FPD), organic light emitting diode (OLED), etching (WET) process. The averaged VOCs mixing ratio in the such workplace, PHOTO was 6.5 ppm, FPH was 6.4 ppm, WET was 2.0 ppm and OLED was 1.3 ppm, respectively. The abundance of VOCs in the workplace were methyl ethyl ketone (MEK) with 2.8 ppm (69%) and acetaldehyde with 0.5 ppm (13.2%). Depending on the semiconductor process characteristics, various VOCs have been observed in the workplace. The VOCs mixing ratio are lower than the workplace regulation standard (TWA), it is necessary to continuously monitor and effectively manage these VOCs.

• Journal of the Korean Society of Safety
• /
• v.35 no.6
• /
• pp.85-92
• /
• 2020

Wet Scrubber reacts the incoming pollutant gas with cleaning water (water + absorbent) to absorb pollutants and release the clean air to the atmosphere. Wet scrubbers and packed tower scrubbers using this principle are widely used in businesses that emit acid gases. In particular, in the etching process using hydrochloric acid (HCl), alkaline washing water (NaOH) having a pH of about 8 to 11 is used to absorb a large amount of acid gas. However, These salts are attached to the injection nozzle (nozzle), filling material (packing), and the demister (Demister), causing air pollution, human damage, and inoperability due to clogging and acid gas discharge. Therefore, In this study, an improvement plan was proposed to manage the washing water with pH 3~4 acidic washing water. The test method takes samples from the Wet Scrubber flue measurement laboratory twice a month for 1 year. Hydrogen chloride (HCl) concentration (ppm) was measured, and nozzle clogging and scale conditions were measured, compared, and analyzed through a differential pressure gauge and a pressure gauge. As a result of the check, it was visually confirmed that the scale was reduced to 50% or less in the spray nozzle, filler, and demister. In addition, the emission limit of hydrogen chloride in accordance with the Enforcement Regulation of the Air Quality Conservation Act [Annex 8] met 3 ppm or less. Therefore, even if the washing water is operated in an acidic pH range of 3 to 4, it is expected to reduce air pollution and human damage due to clogging of internal parts, and it is expected to reduce maintenance costs such as regular cleaning or replacement of parts.

• Journal of Sensor Science and Technology
• /
• v.7 no.1
• /
• pp.73-82
• /
• 1998

In silicon surface micro-machining, the newly developed GPE(gas-phase etching) process was verified as a very effective method for the release of highly compliant micro-structures. The developed GPE system with anhydrous HF gas and $CH_{3}OH$ vapor was characterized and the selective etching properties of sacrificial layers to release silicon micro-structures were discussed. P-doped polysilicon and SOI(silicon on insulator) substrate were used as a structural layer and TEOS(tetraethyorthdsilicate) oxide, thermal oxide and LTO(low temperature oxide) as a sacrificial layer. Compared with conventional wet-release, we successfully fabricated micro-structures with virtually no process-induced striction and residual product.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.17 no.6
• /
• pp.1175-1180
• /
• 2022

STI has been studied a lot as a process technology for wide area planarization according to miniaturization and high integration of semiconductor devices. In this study, as methods for improving the STI profile, wet etching of pad oxide using hydrofluorine solution and dry etching of O₂+CF₄ after STI dry etching were proposed. This process technology showed improvement in profile imbalance and leakage current between patterns according to device density compared to the conventional method. In addition, as a result of measuring the HLD thickness after CMP for a device having the same STI depth and HLD deposition, the measured value was different depending on the device density. It was confirmed that this was due to the difference in the thickness of the nitride film according to the device density after CMP and the selectivity of the slurry.