• Title/Summary/Keyword: 잔류두께

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$C_2F_6$/$CHF_3$ 반응성이온 건식식각 공정시 실리콘 표면에 생성된 잔류막과 표면구조의 연구

  • Yun, Seon-Jin;Jang, Sang-Hwan;Gwon, O-Jun
    • ETRI Journal
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    • v.11 no.1
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    • pp.89-96
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    • 1989
  • $C_2F_6$/$CHF_6$ 플라즈마를 이용한 실리콘 산화막의 반응성이온 식각공정시 실리콘 표면에 형성되는 고분자 잔류막과 근표면 손상영역을 X-선 광전자분광법(x-ray photoelectron spectroscopy)과 러더포드 후방산란법(Rutherford backscattering)을 이용하여 연구하였다. 표면 잔류막은 CF, $CF_2$, $CF_3$, $C-CF_x$, 그리고 C-C/C-H 등의 결합을 가진 불화탄소 고분자로 구성되어 있으며, 또한 C 1s와 Si 2p X-선 광선자 스펙트럼으로부터 C-Si 결합이 존재함을 확인하였다. 반응성이온 식각을 거친 실리콘 표면 구조의 연구결과, 불소와 탄소로 구성된 고분자막($<20 \AA$)이 극표면에 존재하며, 식각 후 공기중에 노출됨에 따라 고분자 잔류층으로 산소가 통과하여 기판을 산화시킴으로써 실리콘 산화막( $~10\AA$)이 그 아래에 형성되었음을 알았다. 그리고 실리콘산화막 아래에 탄소-산소 결합영역이 관찰되었다. 플라즈마 가스의 조성에서 $CHF_3$의 량이 증가함에 따라 고분자 잔류막의 두께가 증가하였으며, 본 연구의 실험조건에서 2분간 overetching한 시편의 경우에도 실리콘 표면 영역의 손상정도가 매우 적음을 발견하였다.

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Production Mechanism of Residual Stress Generated by Multi-Pass Welding of the steel Pipe (강관 적층용접부 잔류응력의 생성기구)

  • Chang, Kyong Ho;Yang, Sung Chul;Kang, Jae Hoon
    • Journal of Korean Society of Steel Construction
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    • v.13 no.4
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    • pp.327-335
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    • 2001
  • The characteristics and production mechanism of residual stress generated by multi-pass welding of the steel pipe were elucidated from the results of three-dimensional thermal elastic-plastic FEM analysis. When the steel pipe was jointed by multi-pass welding, the stress components of circumferential direction and radial direction near welded joints on the inner surface and the outer surface of the pope were tensile. The stress component of axial direction on the inner surface was tensile and on the outer surface was compressive. On the other hands, the production mechanism of residual stress generated by multi-pass welding of the steel pipe was investigated. Residual stress generated by welding of the steel pipe was investigated not only by the thermal history but also by geometrical shape. Then, the generality of the production mechanism of residual stress generated by multi-pass welding was confirmed.

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Compressive Strength and Residual Stress Evaluation of Stub Columns Fabricated of High Strength Steel (고강도강재 단주의 압축강도 및 잔류응력 평가)

  • Lee, Cheol-Ho;Kim, Dae-Kyung;Han, Kyu-Hong;Kim, Jin-Ho;Lee, Seung-Eun;Ha, Tae-Hyu
    • Journal of Korean Society of Steel Construction
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    • v.24 no.1
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    • pp.23-34
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    • 2012
  • In this study, stub columns subjected to concentrical and eccentrical loads were tested to check the applicability of the current local stability criteria (KBC2009, AISC2005) to 800MPa high-strength steel (HSA800). The key test variables in the concentrically loaded tests included the plate-edge restraints and the width-to-thickness ratio normalized by the yield strength of steel. Specimens made of ordinary steel (SM490) were also tested for comparative purposes. Eccentrically loaded stub column tests were conducted for a range of the P-M combinations by controlling the loading eccentricity. All the concentrically loaded specimens with non-compact and slender sections developed sufficient strengths according to the current local stability criteria. All the eccentrically loaded specimens with non-compact H sections also exhibited a sufficient P-M interaction strength that was even higher than that of compact H- section counterparts. Residual stresses were also measured by using the non-destructive indentation method to demonstrate their dependency or independency on the steel material's yield strength. The measured results of this study also indicated that the magnitude of residual stresses bears no strong relation to the yield strength of the steel material.

Finite Element Post-buckling Analysis of Steel-Concrete Composite Column (철골-콘크리트 합성기둥의 후좌굴 거동에 관한 해석 연구)

  • Oh, Myoung Ho;Kim, Myeong Han;Kim, Sang Dae
    • Journal of Korean Society of Steel Construction
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    • v.19 no.6
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    • pp.725-735
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    • 2007
  • The local buckling strength and post-local buckling strength of thin steel plates in the steel-concrete composite column were evaluated by nonlinear finite element analyses. The proposed width-to-thickness limit ratio was based on elastic buckling analyses, in which the increased local buckling capacity of the plate due to the in-filled concrete was considered by the boundary conditions of the thin plate. Considering the initial imperfections and residual stresses, we determined the initial local buckling strength and post-local buckling strength of the thin plates with various width-to-thickness ratios. The formula to evaluate the compressive capacity of the steel-concrete composite column based on the effective width of the plate was proposed. For verification, values determined by the formula were compared with the experimental results.

Investigation of Residual Stress Distributions of Induction Heating Bended Austenitic Stainless Steel (316 Series) Piping (유도 가열 굽힘된 316 계열 오스테나이트 스테인리스 강 배관의 잔류응력 분포 고찰)

  • Kim, Jong Sung;Kim, Kyoung Soo;Oh, Young Jin;Chang, Hyun Young;Park, Heung Bae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.38 no.7
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    • pp.809-815
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    • 2014
  • The induction heating bending process, which has been recently applied to nuclear piping, can generate residual stresses due to thermomechanical mechanism during the process. This residual stress is one of the crack driving forces that have important effects on crack initiation and propagation. However, previous studies have focused only on geometric shape variations such as the change in thickness and ovality. Moreover, very few studies are available on the effects of process variables on residual stresses. This study investigated the effects of process variables on the residual stress distributions of induction heating bended austenitic stainless steel (316 series) piping using parametric finite element analysis. The results indicated that the heat generation rate and feed velocity have significant effects on the residual stresses whereas the moment and bending angle have insignificant effects.

Properties of Sol-Gel PZT Thin films with Thickness for Micro Piezoelectric Actuators (마이크로 압전 엑츄에이터용 Sol-Gel PZT 박막의 두께 변화에 따른 특성)

  • 장연태;박준식;김대식;박효덕;최승철
    • Proceedings of the KAIS Fall Conference
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    • 2001.05a
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    • pp.220-223
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    • 2001
  • Pb가 10% 과잉되고 Zr : Ti = 52 : 48 조성을 갖는 PZT sol이 Pt(3500Å)/Ti(400Å)/SiO₂(3000Å)Si(525㎛)기판 위에 스핀 코팅법으로 반복 코팅된 후, 450℃에서 10분, 650℃에서 2분간 반복 열처리되었다. 이와 같이 다양한 두께로 적층된 박막은 각 시편에 대해 최종적으로 650℃ 30분 동안 어닐링 처리되었다. 제조된 PZT 박막의 두께는 4100Å에서 1.75㎛사이의 4종이었다. 이어서 스퍼터링법으로 Pt전극이 PZT 막 위에 증착되었다. 제조된 PZT 박막의 결정 구조 조사를 위해 XRD, 그리고 미세 구조 및 전기적 특성을 알아보기 위해 FESEM과 P-E 이력 곡선이 각각 관찰되었다. 4100Å에서 1.75㎛까지 두께 증가에 따른 장비상의 포화 이력 한계로 잔류 분극(Pr)값이 25μC/㎠에서 다소 감소되었다. 측정된 X선 회절 결과에서 최초 4회 코팅시 perovskite 결정 구조로 성장한 결정립은 (111)배향이 우세하었으나, 두께가 증가됨에 따라 (111)/(110)값이 감소되었으며, 이를 통해 두께 증가에 따른 (111)배향성이 다소 감소됨을 알 수 있었다. 이상의 결과로부터 제조된 PZT 박막은 큰 힘과 높은 내전압 특성을 갖는 마이크로 압전 액츄에이터에 적용될 수 있을 것으로 생각되었다.

A study on formability of truck frame (트럭 프레임의 성형성에 관한 연구)

  • 민홍기;김의석;이화원
    • Journal of the korean Society of Automotive Engineers
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    • v.15 no.5
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    • pp.22-30
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    • 1993
  • 본 연구는 MSC/DYNA EXPLICIT CODE를 이용하여 자동차용 샤시 프레임의 성형성을 파악하기 위한 모델링 방식과 단계별 변형양상, 컴퓨터 시뮬레이션의 결과인 스프링백, 잔류응력, 두께변화, 변형률 등을 소개하기로 한다. 1. 프레임 스탬핑 개요. 2. 해석 모델 및 성형조건. 3. 해석결과 및 고찰.

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Stamping analysis of automotive wheel disc (자동차용 휠 디스크 스탬핑 해석)

  • 김주성;민홍기
    • Journal of the korean Society of Automotive Engineers
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    • v.14 no.3
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    • pp.26-31
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    • 1992
  • 본 연구에서는 ABBAQUS/EXPLICIT CODE를 이용하여 자동차용 휠 디스크의 성형성을 파악하기 위한 모델링 방식과 컴퓨터 시뮬레이션의 결과인 스프링백, 잔류응력, 두께 변화, 변형률 등을 소개하기로 한다. 컴퓨터 시뮬레이션을 휠 디스크 스탬핑에 이용한 경우 스탬핑시 발생하는 여러현상을 쉽게 예측할 수 있으며, 또한 금형의 Geometry 결정 및 홀더와 펀치의 작용하중 등 금형 설계시 요구되는 데이타 확보가 매우 용이하다.

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Formation of Passivation Layer and Its Effect on the Defect Generation during Trench Etching (트렌티 식각시 식각 방지막의 형성과 이들이 결함 생성에 미치는 영향)

  • Lee, Ju-Wook;Kim, Sang-Gi;Kim, Jong-Dae;Koo, Jin-Gon;Lee, Jeong-Yong;Nam, Kee-Soo
    • Korean Journal of Materials Research
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    • v.8 no.7
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    • pp.634-640
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    • 1998
  • A well- shaped trench was investigated in view of the defect distribution along trench sidewall and bottom using high resolution transmission electron microscopy. The trench was formed by HBr plasma and additive gases in magnetically enhanced reactive ion etching system. Adding $0_2$ and other additive gases into HBr plasma makes it possible to eliminate sidewall undercut and lower surface roughness by forming the passivation layer of lateral etching, resulted in the well filled trench with oxide and polysilicon by subsequent deposition. The passivation layer of lateral etching was mainly composed of $SiO_xF_y$ $SiO_xBr_y$ confirmed by chemical analysis. It also affects the generation and distribution of lattice defects. Most of etch induced defects were found in the edge region of the trench bottom within the depth of 10$\AA$. They are generally decreased with the thickness of residue layer and almost disappeared below the uni¬formly thick residue layer. While the formation of crystalline defects in silicon substrate mainly depends on the incident angle and energy of etch species, the region of surface defects on the thickness of residue layer formed during trench etching.

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The Minimization of Residual Layer Thickness by using optimized dispensing method in UVnanoimprint Lithography Process (UV 나노임프린트 리소그래피 공정에서 레지스트 도포의 최적화를 통한 잔류층 두께의 최소화)

  • Kim K.D.;Jeong J.H.;Sim Y.S.;Lee E.S.;Kim J.H.;Cho Y.K.;Hong S.C.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.06a
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    • pp.633-636
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    • 2005
  • Imprint lithography is a promising method for high-resolution and high-throughput lithography using low-cost equipment. As with other nanoimprint methods, ultraviolet-nanoimprint lithography (UV-NIL) resolution appears to be limited only by template resolution, and offers a significant cost of ownership reduction when compared to other next generation lithography (NGL) methods such as EUVL and 157 nm lithography. The purpose of this paper is to suggest optimum values of control parameters of Imprio 100 manufactured by Molecular Imprint, Inc., which is the first commercially available UV-NIL tool, for sound nanoimprint. UV-NIL experiments were performed on Imprio 100 to find dispensing recipe for avoiding air entrapment. Dispensing recipe related to residual layer thickness and uniformity was optimized and 40 nm thick residual layer was achieved.

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