• Journal of the Korean Ceramic Society
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• v.53 no.3
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• pp.349-353
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• 2016

We prepared a number of reaction-bonded silicon carbides (RBSCs) made from various mixing ratios of raw SiC particles, and investigated their microstructure and etch characteristics by Reactive Ion Etch (RIE). Increasing the amount of $9.5{\mu}m$-SiC particles results in a microstructure with relatively coarser Si regions. On the other hand, increasing that of $2.6{\mu}m$-SiC particles produces much finer Si regions. The addition of more than 50 wt% of $2.6{\mu}m$-SiC particles, however, causes the microstructure to become partially coarse. We also evaluated their etching behaviors in terms of surface roughness (Ra), density and weight changes, and microstructure development by employing Confocal Laser Scanning Microscope (CLSM) and Scanning Electron Microscope (SEM) techniques. During the etching process of the prepared samples, we confirmed that the residual Si region was rapidly removed and formed pits isolating SiC particles as islands. This leads to more intensified ion field on the SiC islands, and causes physical corrosion on them. Increased addition of $2.6{\mu}m$-SiC particles produces finer residual Si region, and thus decreases the surface roughness (Ra.) as well as causing weight loss after etching process by following the above etching mechanism.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.12
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• pp.1078-1084
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• 2006

Impurity contamination induced by $CF_4\;and\;HBr/Cl_2/O_2$ plasma etching on Si surface was examined by using surface spectroscopes. XPS(x-ray photoelectron spectroscopy) surface analysis showed that F of 0.4 at % exists in the surface layer in the form of Si-F bonding but Br and Cl are below the detection limit $(0.1{\sim}1.0%)$ of the spectroscope. Static-SIMS(secondary ion mass spectrometry) surface analysis showed that the etched Si surface was contaminated with etching gas elements such as H, F, Cl and Br, and they existed to the depth of about $20{\sim}40nm$. The etched Si surface was treated with three different methods that were HF dip, thermal oxidation followed by HF dip and oxygen-plasma oxidation followed by HF dip. They showed an effect in reducing the impurity contamination and the oxygen-plasma oxidation followed by HF dipping method appears to be a little bit more effective.

• Journal of the Semiconductor & Display Technology
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• v.14 no.3
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• pp.7-11
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• 2015

In order to protect the patterned mask from contamination during lithography process, pellicle has become a critical component for Extreme Ultraviolet (EUV) lithography technology. According to EUV pellicle requirements, the pellicle should have high EUV transmittance and robust mechanical property. In this study, silicon nitride, which is well-known for its remarkable mechanical property, was used as a pellicle membrane material to achieve high EUV transmittance. Since long silicon wet etching process time aggravates notching effect causing stress concentration on the edge or corner of etched structure, the remaining membrane is prone to fracture at the end of etch process. To overcome this notching effect and attain high transmittance, we began preparing a rather thick (200 nm) $SiN_x$ membrane which can be stably manufactured and was thinned into 43 nm thickness with HF wet etching process. The measured EUV transmittance shows similar values to the simulated result. Therefore, the result shows possibilities of HF thinning processes for $SiN_x$ EUV pellicle fabrication.

• Journal of the Korean Ceramic Society
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• v.39 no.4
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• pp.409-412
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• 2002

Under atmospheric pressure, apparently homogeneous and stable plasma can be generated from insulator barrier rf plasma generators each of which has an rf powered cathode and a grounded anode covered with a dielectric insulating material. In order to characterize the generating plasma under atmospheric pressure, some basic characteristic have been evaluated by the Langmuire probe method as well as by optical emission spectroscopy. From the result of plasma characteristics, the generated plasma was verified to be nonequilibrium; T(electron)>T(excitation)>T(gas). High rate Si(100) etching (($1.5{\mu}m$/min) were achieved by using He plasma containing a small amount of $CF_4$.

• Journal of the Microelectronics and Packaging Society
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• v.6 no.3
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• pp.65-71
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• 1999

The effects of mask materials and etching solutions on the dimensional accuracy of V-groove were studied for the alignment between optoelectronic devices and optical fibers in optical packaging. PECVD nitride, LPCVD nitride, or thermal oxide($SiO_2$) was used as a mask material. The anisotropic etching solution was KOH(40wt%) or the mixture of KOH and IPA. LPCVB nitride has the best etching selectivity and thermal oxide was etched most rapidly in KOH(40wt%) at $85^{\circ}C$ among the mask materials studied here. The V-groove size enlarged than the designed value. This phenomenon was due to the undercutting benearth the mask layer from the etching toward Si (111) plane. The etch rate of (111) plane wart 0.034 - 0.037 $\mu\textrm{m}$/min in KOH(40wt%). This rate was almost same regardless of mask materials. When IPA added to KOH(40wt%), the etch rate of (100) plane and (111) plane decreased, but etching ratio of (100) to (111) plane increased. Consequently, the undercutting phenomenon due to etching toward (111) plane decreased and the size of V-groove could be controlled more accurately.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.79-79
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• 1999

The varous techniques for fabrication of si or metal tip as a field emission electron source have been reported due to great potential capabilities of flat panel display application. In this report, 240nm thermal oxide was initially grown at the p-type (100) (5-25 ohm-cm) 4 inch Si wafer and 310nm Si3N4 thin layer was deposited using low pressure chemical vapor deposition technique(LPCVD). The 2 micron size dot array was photolithographically patterned. The KOH anisotropic etching of the silicon substrate was utilized to provide V-groove formation. After formation of the V-groove shape, dry oxidation at 100$0^{\circ}C$ for 600 minutes was followed. In this procedure, the orientation dependent oxide growth was performed to have a etch-mask for dry etching. The thicknesses of the grown oxides on the (111) surface and on the (100) etch stop surface were found to be ~330nm and ~90nm, respectively. The reactive ion etching by 100 watt, 9 mtorr, 40 sccm Cl2 feed gas using inductively coupled plasma (ICP) system was performed in order to etch ~90nm SiO layer on the bottom of the etch stop and to etch the Si layer on the bottom. The 300 watt RF power was connected to the substrate in order to supply ~(-500)eV. The negative ion energy would enhance the directional anisotropic etching of the Cl2 RIE. After etching, remaining thickness of the oxide on the (111) was measured to be ~130nm by scanning electron microscopy.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1974-1976
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• 1996

An electrostatically driven comb actuator with $525{\mu}m$ height was fabricated using (110) Si anisotropic etching in the Potassium Hydroxide(KOH) solution. The etch-rate and etch-rate ratio are strongly dependent on the weight % and temperature of KOH solution. We developed the optimal condition for the anisotropic etching on (110) wafer with varying these conditions. The force that the comb-drive actuator generates is inversely proportional to the distance of gap and proportional to the height of the comb electrodes. The electrodes must have the high aspect ratio. The (110) Si anisotropic etching is very useful to get a high aspect ratio structure.

• Transactions on Electrical and Electronic Materials
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• v.1 no.2
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• pp.1-6
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• 2000

This article presents the experiments and considerations possible about gate etching in polysilicon when oxygen gas is added in chamber, We propose the novel study with optical emission spectroscopy in polysilicon etching. It is shown that added oxygen gases play an important role in enhencement of density in chlorine gases as a scavenger of silicon from SiCl$\_$x/. And a small amount of Si-O bonds are deposited and then the deposited thin film protect silicon dioxyde against reaction chlorine with silicon in SiO$_2$. Consequently, we can improve the selectivity of polysilicon the silicon dioxide, which is clearly explained in this model.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.5
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• pp.396-401
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• 1999

In this study, $Ar^+$ ion laser etching process of single/poly-crystalline Si with $CCl_2F_2$ gas is investigated for MEMS applications. In general, laser direct etching process is useful in microelectronic process, fabrication of micro sensors and actuators, rapid prototyping, and complementary processing because of the advantages of 3D micromachining, local etching/deposition process, and maskless process with high resolution. In this study, a pyrolytic method, in which $CCl_2F_2$ gasetches molten Si by the focused laser, was used. In order to analyze the temperature profile of Si by the focused laser, the 3D heat conduction equation was analytically solved. In order to investigate the process parameters dependence of etching characteristics, laser power, $CCl_2F_2$ gas pressure, and scanning speed were varied and the experimental results were observed by SEM. The aspect ratio was measured in multiple scanning and the simple 3D structure was fabricated. In addition, the etching characteristics of $6\mum$ thick poly-crystalline Si on the insulator was investigated to obtain flat bottom and vertical side wall for MEMS applications.

• Electrical & Electronic Materials
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• v.8 no.1
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• pp.90-94
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• 1995

Reactive Ion Etching(RIE) of Si$_{3}$N$_{4}$ in a CF$_{4}$/O$_{2}$ gas plasma exhibits such good anisotropic etching properties that it is widely employed in current VLSI technology. However, the RIE process can cause serious damage to the silicon surface under the Si$_{3}$N$_{4}$ layer. When an atmospheric pressure chemical vapor deposited(APCVD) SiO$_{2}$ layer is used as a etch-stop material for Si$_{3}$N$_{4}$, it seems inevitable to get a good etch selectivity of Si$_{3}$N$_{4}$ with respect to SiO$_{2}$. Therefore, we have undertaken thorough study of the dependence of the etch rate of Si$_{3}$N$_{4}$ plasmas on $O_{2}$ dilution, RF power, and chamber pressure. The etch selectivity of Si$_{3}$N$_{4}$ with respect to SiO$_{2}$ has been obtained its value of 2.13 at the RF power of 150 W and the pressure of 110 mTorr in CF$_{4}$ gas plasma diluted with 25% $O_{2}$ by flow rate.