• 한국세라믹학회지
• /
• 제40권9호
• /
• pp.886-890
• /
• 2003

단결정 LiNbO$_3$를 helicon wave plasma 방법으로 식각시 bias power와 CF$_4$, HBr, SR$_{6}$가 혼합된 gas 유량에 따른 식각 속도와 rms roughness 값의 특성을 관찰하였다. 식각된 깊이는 surface profiler로 관찰하였으며 rms roughness 값은 Atomic Force Microscopy (AFM)으로 측정하였다. Bias power 증가함에 따라 500W에서 가장 높은 식각 속도와 가장 평탄한 표면형상을 얻을 수 있었으며, CF$_4$, HBr, SF$_{6}$ gas 유량을 각각 10～30 sccm으로 증가시킴에 따라 식각 속도는 CF$_4$, HBr, SF$_{6}$ gas 유량이 10 sccm, 30 sccm, 10 sccm에서 가장 높게 나타났으며, rms roughness 값은 CF$_4$, HBr, SF$_{6}$ gas 유량이 30 sccm, 10 sccm, 30 sccm에서 가장 낮은 표면 조도를 나타내었다.

• 대한화학회지
• /
• 제45권4호
• /
• pp.351-356
• /
• 2001

철, 코발트, 니켈 합금을 이용한 탄소확산-수소플라즈마 에칭법으로 다이아몬드 자체막의 표면을 매우 평탄하게 할 수 있었다. 이 방법에서의 다이아몬드 자체막을 합금과 몰리브데늄 기판 사이에 위치시켜 금속-다이아몬드-몰리브데늄(MDM) 샌드위치 형태의 샘플 세 트를 이루게 하였다. 이 샘플세트를 마이크로 웨이브 플라즈마 장치에 장착하여 수소 플라즈마를 발생시켜서 기판온도가 섭씨 1,000 이상이 되도록 하였다. 이와 같은 과정들은 탄소확산-수소플라즈마 방법이라고 하였다. 다이아몬드 자체막 표면을 에칭한 후 표면 거칠기, 표면형상, 에칭한 다이아몬드 표면속의 불순물의 침투를 조사하였다. 결론적으로, 탄소 확산-수소 플라즈마 에칭법은 전자 디바이스에 응용할 수 있는 매우 평탄한 다이아몬드 표면을 형성시키는 방법임을 알 수 있다.

• 한국세라믹학회지
• /
• 제39권6호
• /
• pp.570-575
• /
• 2002

현재 전기 . 전자 기술의 추세는 소형화를 비롯하여 집적화, 저전력화, 저가격화의 장점을 가진 MEMS(Micro Electro Mechanical Systems) device의 개발에 주력하고 있으며, 이를 위해서는 고종횡비와 높은 식각 속도를 가진 HDP(High Density Plasma) etching 기술 개발이 필수적이라 할 수 있다. 이를 위하여 우리는 Inductively Coupled Plasma(ICP) 장비를 이용하여 각 공정 변수에 의한 실리콘 deep trench식각 반응을 연구하였다. 실험 공정 변수인 platen power, etch/passivation cycle time에서 etching 단계 시간에 따른 변화와 SF$_{6}$:C$_4$F$_{8}$ 가스유량을 변화시켜 연구하였으며 또한 이들의 profile, scallops, 식각 속도, 균일도, 선택비도 관찰하였다.

• Journal of Magnetics
• /
• 제12권2호
• /
• pp.81-83
• /
• 2007

Etching of NiFe films covered with an organic photo-resist or Ti was successfully performed by an inductively coupled plasma-reactive ion etching (ICP-RIE) system using $CHF_3/O_2/NH_3$ discharges exchanging $CHF_3$ for $CH_4$ gas gradually. Experimental results showed that the organic photo-resist mask can be applied to the NiFe etching. In the case of the Ti metal mask, it was found that the etching-selectivity Ti against NiFe was significantly varied from 7.3 to ${\sim}0$ by changing $CHF_3/CH_4/O_2/NH_3$ to $CH_4/O_2/NH_3$ discharges used in the ICP-RIE system. These results show that the present RIE of NiFe was dominated by a chemical reaction rather than a physical sputtering.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
• /
• pp.182-182
• /
• 2012

Plasma etching is used in various semiconductor processing steps. In plasma etcher, optical- emission spectroscopy (OES) is widely used for in-situ endpoint detection. However, the sensitivity of OES is decreased if polymer is deposited on viewport or the proportion of exposed area on the wafer is too small. Because of these problems, the object is to investigate the suitability of using plasma impedance monitoring (PIM) and self plasma optical emission spectrocopy (SPOES) with statistical approach for in-situ endpoint detection. The endpoint was determined by impedance signal variation from I-V monitor (VI probe) and optical emission signal from SPOES. However, the signal variation at the endpoint is too weak to determine endpoint when $SiO_2$ and SiNx layers are etched by fluorocarbon on inductive coupled plasma (ICP) etcher, if the proportion of $SiO_2$ and SiNx area on Si wafer are small. Therefore, modified principal component analysis (mPCA) is applied to them for increasing sensitivity. For verifying this method, detected endpoint from impedance monitoring is compared with optical emission spectroscopy.

• 한국표면공학회지
• /
• 제34권5호
• /
• pp.516-521
• /
• 2001

Dry etching of Si wafer and $SiO_2$ layers was performed using He/Cl$_2$ mixture plasma by diode-type reactive ion etcher (RIE) system. For Si etching, the Cl molecules react with the Si molecules on the surface and become chemically stable, indicating that the reactants need energetic ion bombardment. During the ion assisted desorption, energetic ions would damage the photoresist (PR) and produce the bad etch Si-profile. Moreover, we have examined the characteristics of the Cl-Si reaction system, and developed the new fabrication procedures with a $Cl_2$/He mixture for Si and $SiO_2$-etching. The developed novel fabrication procedure allows the RIE to be unexpensive and useful a Si deep etching system. Since the etch rate was proved to increase linearly with fHe and the selectivity of Si to $SiO_2$ etch rate was observed to be inversely proportional to fHe.

• 한국방사성폐기물학회:학술대회논문집
• /
• 한국방사성폐기물학회 2004년도 학술논문집
• /
• pp.32-42
• /
• 2004

Recently, plasma surface-cleaning or surface-etching techniques have been focused in respect of the decontamination of spent or used nuclear parts and equipment. In this study the removal rate of metallic cobalt surface is experimentally investigated via its surface etching rate with a $CF_4-o_2$mixed gas plasma. Experimental results reveal that a mixed etchant gas with about 80% $CF_4$-20% $O_2$ (molar) gives the highest reaction rate and the rate reaches 0.06 ${\mu}m$/min at $380^{\circ}C$ and ion-assisted etching dramatically enhances the surface reaction rate. With a negative 300 V DC bias voltage applied to the substrate, the surface reaction initiation temperature lowers and the rate increases about 20 times at $350^{\circ}C$ and up to 0.43 ${\mu}m$/min at $380^{\circ}C$, respectively. Surface morphology analysis confirms the etching rate measurements. Auger spectrum analysis clearly shows the adsorption of fluorine atoms on the reacted surface. From the current experimental findings and the results discussed in previous studies, mechanistic understanding of the surface reaction, fluorination and/or fluoro-carbonylation reaction, is provided.

• 한국전기전자재료학회논문지
• /
• 제13권12호
• /
• pp.996-1002
• /
• 2000

Ferroelectric (Ba, Sr) TiO$_3$(BST) thin films have attracted much attention for use in new capacitor materials of dynamic random access memories (DRAMs). In order to apply BST to the DRAMs, the etching process for BST thin film with high etch rate and vertical profile must be developed. However, the former studies have the problem of low etch rate. In this study, in order to increase the etch rate, BST thin films were etched with a magnetically enhanced inductively coupled plasma(MEICP) that have much higher plasma density than RIE (reactive ion etching) and ICP (inductively coupled plasma). Experiment was done by varying the etching parameters such as CF$_4$/(CF$_4$+Ar) gas mixing ratio, rf power, dc bias voltage and chamber pressure. The maximum etch rate of the BST films was 170nm/min under CF$_4$/CF$_4$+Ar) of 0.1, 600 W/-350 V and 5 mTorr. The selectivities of BST to Pt and PR were 0.6 and 0.7, respectively. Chemical reaction and residue of the etched surface were investigated with X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectroscopy (SIMS).

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
• /
• pp.391-392
• /
• 2012

In these days, the desire for the precise and tiny displays in mobile application has been increased strongly. Currently, laser displays ranging from large-size laser TV to mobile projectors, are commercially available or due to appear on the market [1]. In order to achieve a mobile projectors, the semiconductor laser diodes should be used as a laser source due to their size and weight. In this presentation, the continuous etch characteristics of Pd and AlGaN/GaN superlattice for the fabrication of blue laser diodes were investigated by using inductively coupled $CHF_3$ and $Cl_2$ -based plasma. The GaN laser diode samples were grown on the sapphire (0001) substrate using a metal organic chemical vapor deposition system. A Si-doped GaN layer was grown on the substrate, followed by growth of LD structures, including the active layers of InGaN/GaN quantum well and barriers layer, as shown in other literature [2], and the palladium was used as a p-type ohmic contact metal. The etch rate of AlGaN/GaN superlattice (2.5/2.5 nm for 100 periods) and n-GaN by using $Cl_2$ (90%)/Ar (10%) and $Cl_2$ (50%)/$CHF_3$ (50%) plasma chemistry, respectively. While when the $Cl_2$/Ar plasma were used, the etch rate of AlGaN/GaN superlattice shows a similar etch rate as that of n-GaN, the $Cl_2/CHF_3$ plasma shows decreased etch rate, compared with that of $Cl_2$/Ar plasma, especially for AlGaN/GaN superlattice. Furthermore, it was also found that the Pd which is deposited on top of the superlattice couldn't be etched with $Cl_2$/Ar plasma. It was indicating that the etching step should be separated into 2 steps for the Pd etching and the superlattice etching, respectively. The etched surface of stacked Pd/superlattice as a result of 2-step etching process including Pd etching ($Cl_2/CHF_3$) and SLs ($Cl_2$/Ar) etching, respectively. EDX results shows that the etched surface is a GaN waveguide free from the Al, indicating the SLs were fully removed by etching. Furthermore, the optical and electrical properties will be also investigated in this presentation. In summary, Pd/AlGaN/GaN SLs were successfully etched exploiting noble 2-step etching processes.

• 한국방사성폐기물학회:학술대회논문집
• /
• 한국방사성폐기물학회 2005년도 Proceedings of The 6th korea-china joint workshop on nuclear waste management
• /
• pp.300-315
• /
• 2005

Recently plasma surface-cleaning or surface-etching techniques have been focused in the respect of decontamination of spent or used nuclear parts and equipment. In this study decontamination rate of metallic cobalt surface was experimentally investigated via its surface etching rate with a $CF_4-O_2$ mixed gas plasma and metallic surface wastes of cobalt oxides were simulated and decontaminated with $NF_3$ - Ar mixed gas plasma. Experimental results revealed that a mixed etchant gas with about $80{\%}\;CF_4-20{\%}\;O_2$ gives the highest reaction rate of cobalt disk and the rate reaches with a negative 300 DC bias voltage up to $0.43\;{\mu}m$/min at $380^{\circ}C$ and $20{\%}\;NF_3-80\%$ Ar mixed gas gives $0.2\;{\mu}m$/min of reaction rate of cobalt oxide film.