• Proceedings of the KIEE Conference
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• 2000.11c
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• pp.519-521
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• 2000

The application of low dieletric constant material instead of $SiO_2$ has been considered to reduce interconnection delay, crosstalk, power exhaustion. Methylsilsesquioxane (MSSQ) have a dieletric constant less than k>3 which is lower than that for the convention $SiO_2$ insulator ($k{\sim}4$). The Propose of this study is to know etching rate of MSSQ. Expermentation in this paper use RIE(Reactive ion Etching) and centre) flow rate of $CF_4/O_2$ gas, RF power.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.402-402
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• 2012

최근 반도체 공정 중 fluorocarbon (CxHyFz) 가스와 함께 플라즈마 밀도가 큰 유도결합형 플라즈마을 사용한 식각장비가 많이 사용되고 있다. 특히 저 유전상수 값을 가지는 박막을 밀도가 큰 플라즈마와 함께 fluorocarbon 가스를 이용하여 식각을 하게 되면 매우 복잡한 현상이 생긴다. 따라서 식각률에 대한 모델을 세우고 적용하는 일이 매우 어렵다. 본 연구에서는 CF4가스를 Ar가스와 함께 혼합하고 기판 플라즈마와 유도결합형 플라즈마를 동시에 가진 식각장비를 사용하여, 저 유전상수 값을 갖는 박막을 식각하였다. 또한, 간단한 식각모델인 Langmuir adsorption model를 이용하여 식각률(Etch rate)에 대한 합리적인 이해를 얻기 위해, 기판과 유도결합형 플라즈마의 파워에 따른 식각률을 계산하고, 식각모델에서 사용되는 매개변수인 이온플럭스(Ion Flux)와 식각수율(Etch yield)을 연구하였다. 기판의 플라즈마 파워가 20에서 100 W 증가하면서 식각률이 269에서 478 nm/min로 증가하였으며, 식각수율이 0.4에서 0.59로 증가하는 것을 관찰하였다. 반면에 기판의 플라즈마 파워 증가에 따라 이온 플럭스는 3.8에서 $4.7mA/cm^2$로 변화가 크지 않았다. 또한, 유도결합형 플라즈마의 파워가 100에서 500 W 증가하면서, 식각률이 117에서 563 nm/min로 증가하였으며, 이온플럭스가 1.5에서 $6.8mA/cm^2$으로 변화하였다. 그러나, 식각수율은 0.46에서 0.48로 거의 변화하지 않았다. 그러므로 저 유전상수 값을 가지는 박막 식각의 경우, 기판의 플라즈마는 식각수율을 증가시키며 유도결합형 플라즈마는 이온 플럭스를 증가시켜 박막 식각에 기여하는 것으로 사료된다.

• Korean Journal of Materials Research
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• v.16 no.3
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• pp.151-156
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• 2006

A method for fabrication of nano-scale GaN structure by inductively coupled plasma etching is proposed, exploiting a thermal dewetting of Pt thin film as an etch mask. The nano-scale Pt metal islands were formed by the dewetting of 2-dimensional film on $SiO_2$ dielectric materials during rapid thermal annealing process. For the case of 30 nm thick Pt films, pattern formation and dewetting was initiated at temperatures greater $600^{\circ}C$. Controlling the annealing temperature and time as well as the thickness of the Pt metal film affected the size and density of Pt islands. The activation energy for the formation of Pt metal island was calculated to be 23.2 KJ/mole. The islands show good resistance to dry etching by a $CF_4$ based plasma for dielectric etching indicating that the metal islands produced by dewetting are suitable for use as an etch mask in the fabrication of nano-scale structures.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.8
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• pp.1159-1163
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• 2006

This experiment was performed to examine the influences of high ambient temperature on milk production, nutrient digestibility, energy and protein sufficiency ratio, and plasma metabolites concentration in lactating cows. In a $2{\times}2$ crossover design, four multiparous lactating Holstein cows were maintained in a chamber under treatment of constant moderate ($18^{\circ}C$) ambient temperature (MT) or high ($28^{\circ}C$) ambient temperatures (HT). The DMI and milk protein yield were significantly lower in HT (p<0.05). The milk yield, milk lactose yield, and milk SNF yield tended to be lower in HT (p<0.10). No statistical differences for 4% fat-corrected milk and milk fat yield were observed. Rectal temperatures were significantly higher in HT than MT (p<0.05). The apparent DM, OM, ether extract, CF, and ash digestibility did not differ between treatments. On the other hand, the apparent CP digestibility was increased significantly (p<0.05) and nitrogen free extract tended to increase (p<0.10) in HT. The sufficiency ratio of ME and DCP intake for each requirement tended to be lower in HT than in MT (p<0.10). Concentrations of total protein (TP), albumin, and urea nitrogen in plasma did not differ between treatments. Plasma 3-methylhistidine (3MH) concentration as a marker of myofibrillar protein degradation tended to be higher in HT (p<0.15). In conclusion, high ambient temperature was associated with a lower energy and protein sufficiency ratio, and decreased milk protein production, even though the body protein mobilization tended to be higher.

• Korean Journal of Materials Research
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• v.3 no.4
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• pp.327-335
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• 1993

Using a RF cylindrical magnetron operated with two electromagnets having a Helmholz configuration, RF magnetron plasma properties and characteristics of reactive ion ething of Si were investigated as a function of applied magnetic field strengths using 3mTorr $CF_4/H_2$ and $CHF_3$. Also, I-V characteristics of Schottky diodes, which were made of silicons etched under different applied magnetic field strengths and gas environments, were measured to investigate the degree of radiation damage during the reactive ion etching. As the magnetic field strent;th increased, ion densities and radical densities of the plasmas were increased linearly, however, the dc self-bias voltages induced on the powered electrode, where the specimen are located, were decreased exponentially. Maximum etch rates, which were 5 times faster than that etched without applied magnetic filed, were obtained using near lOOGauss, and, under these conditions, little or no radiation damages on the etched silicons were found.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.1111-1113
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• 2004

n+ etching process is investigated in the fabrication of TFF-LCD using low resistance data line of Mo/Al/Mo. Problems of consumption of upper Mo layer and contamination of channel area are resolved. Either of HCl or $Cl_2$ can be selected as a main etchant gas, and either of $SF_6$ or $CF_4$ can be selected as an additive. Plasma treatment after n+ etching process can reduce the off-current high problem.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.12
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• pp.824-828
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• 2016

In this study, effects of ICP (inductively coupled plasma) treatment on PAR thin film have been investigated. A maximum etch rate of the PAR thin films and the selectivity of PAR to PR were obtained as 110 nm/minand 1.1 in the $CF_4/O_2$ (5:15 sccm) gas mixture. We present the surface properties of PAR thin film with various treatment conditions. The surface morphology and cross section of the PAR thin film was observed by AFM (atomic force microscopy) and FE-SEM (filed emission scanning electron microscopy).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.140-141
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• 2007

반도체 소자의 공정에 있어서 device scaling으로 인한 고유전 게이트 산화막 (high-k dielectics thin film)의 공정 개발 확보 방안이 필요하다. 본 논문에서는 유도결합 플라즈마를 이용하여 고유전율 박막을 식각하였다. CF4, SF6 등의 가스에서 금속-F, 금속-S 결합의 낮은 휘발성으로 인하여 시료 표면에 잔류하여 낮은 식각률을 보이며 측벽 잔류물을 형성하였으며, HBr, Cl 기반 플라즈마에서 금속-Br, 금속-Cl 결합은 시료 표면으로부터 탈착이 용이하여 효과적인 식각이 이루어짐을 확인할 수 있었다.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.40-40
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• 2000

직접 회로의 소자크기가 더욱 미세화에 따라, 기존에 사용하는 금속 배선의 저항과 금속 배선과 층간 유전 물질에 의한 정전용량의 증가로 인한 시간 지연 (RC time delay) 문제가 크게 대두되고 있다. 이 문제를 해결하기 위해 비유전율이 낮은 물질을 층간 유전체로 사용하여 정전용량을 낮추는 것이 필요하다. 기존의 실리콘 산호막 대신에 MSSQ(methylsilsequioxance)를 이용할 때 필요한 건식 식각 공정을 연구하였다. MSSQ 물질을 patterning 하기 위해 습식 공정의 부산물인 폐액 등의 문제점이 발생하지 않을 뿐만 아니라, 소자의 손상이 적고 선택비가 높으며, 식각의 이방성을 향상시킬 수 있는 장점을 갖고 있는 반응 이온 식각기(reactive ion etchin)을 이용하였다. CF4/O2 plasma를 사용하였는데, 가스의 양의 flow rate와 조성비, RF pover(50, 100, 150 W)등의 변화에 따른 식각 특성을 알아보았다. atep, SEM, AFM등을 이용하여 측정·분석하였다.

• Korean Journal of Biological Psychiatry
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• v.6 no.2
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• pp.209-218
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• 1999

Objectives : The aims of this study were to discriminate the clinical differences, to measure the estrogen and homovanillic acid levels, to evaluate a correlation between estrogen and homovanillic acid, and to identify an association of cognitive deficit with estrogen and homovanillic acid among male and female schizophrenics. Methods : In addition to the structured interviews, the plasma estrogen levels by radioimmunoassay and the homovanillic acid levels by HPLC were measured in 20 male and 21 female schizophrenics as well as 10 healthy male and 9 female controls. Results : 1) The plasma estrogen levels were higher in females than males, and significantly higher in female schizophenics than female controls. The homovanillic acid levels were higher in female schizophrenics than female controls, and were lower in male schizophrenics than male controls. 2) The onset age seemed to be earlier in male schizophrenics, and the frequency of admission, duration of antipsychotic drug administration, dosage of antipsychotics and duration of illnesses were more in males. The estrogen and homovanillic acid levels were significantly higher in female schizophrenics. 3) The estrogen levels had a significant positive correlation with sex, age and onset age, while the homovanillic acid levels did with sex. However, estrogen were not correlated with homovanillic acid levels. 4) The estrogen and homovanillic acid levels were not significantly different between male and female schizophrenics with cognitive deficits. In the schizophrenic patients without cognitive deficits, the estrogen levels were significantly higher in females, while there were no significant sex differences in homovanillic acid. 5) In the male and female schizophrenics predominantly with negative symptoms, there were no significant differences in estrogen and homovanillic acid levels. In those predominantly with positive symptoms, the estrogen levels were significantly higher in females, while there were no sex differences in homovanillic acid levels. 6) In schizophrenics with undifferentiated subtype, the estrogen and homovanillic acid levels were significantly higher in females. In those with paranoid or disorganized subtypes, the estrogen levels were significantly higher in females, while there were no sex differences in the homovanillic acid levels. 7) The mean values of PANSS-negative, PANSS-total, PANSS-CF, MMSE-K and estrogen levels were significantly higher in male schizophrenics with cognitive deficits. The mean values of illness duration, CGI, PANSS-positive, PANSS-negative, PANSS-total, PANSS-CF and MMSE-K were significantly higher in female schizophrenics with cognitive deficits. 8) The variables which showed significant correlation with cognitive deficits were PANSS-negative, PANSS-total, PANSS-CF, MMSE-K and estrogen levels in male schizophrenics. The variables which showed significant correlation with cognitive deficits were subtypes, onset age, illness durataion, CGI, PANSS-positive, PANSS-negative, PANSS-total, PANMSS-CF and MMSE-K in female schizophrenics. The estrogen levels were significantly correlated with admission frequencies, history of antipsychotic administration, duration of antipsychotic administration and cognitive deficits in male schizophrenics, while age were not correlated with in females. The homovanillic acid levels had a significant correlation with subtypes and onset age in male schizophrenics, while there were no correlation among variables in females. Conclusions : Although the plasma concentrations of estrogen and homovanillic acid in female schizophrenics were significantly higher than males, we could not find an association between them. Furthermore, the various factors affecting on the cognitive deficits, estrogen and homovanillic acid levels seemed to be somewhat different according to sex.