Browsing by Author "LIN, YC"

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0.35-MU-M PATTERN FABRICATION USING QUARTZ-ETCH ATTENUATE PHASE-SHIFTING MASK IN AN I-LINE STEPPER WITH A 0.50-NA AND A 0.60-SIGMA
(1995-02-01)
LOONG, WA
;
SHY, SL
;
LIN, YC
;
交大名義發表
;
應用化學系
A new method, namely, top critical dimension exposure-defocus tree (TCD E-D Tree), has been developed in this paper and used to analyze simulation results for quartz-etch attenuated phase-shifting mask (APSM). Simulation studies using Depict-3 (from TMA) on isolated and dense patterns indicate that numerical aperture (NA) 0.5 has greater depth of focus (DOF); NA 0.6 has larger exposure latitude (EL); best degree of coherence (sigma, sigma) value is between 0.6 approximately 0.7; best intensity transmittance (IT) range is 4 approximately 6%; the effect of mask bias on DOF and EL is rather small. The effect of sigma on space patterns including contact holes shows an inverse trend compared with lines. While conventional binary intensity mask (BIM) shows a 0.9 mum total DOF for dense line; APSM in our study (zero mask bias, 4% IT, 0.5 NA, 0.6 sigma) shows a 1.2 mum total DOF (30% improvement). The experimental results are highly in agreement with simulation. However, APSM shows only an insignificant improvement for EL in this study. Stepper with a NA of 0.5 and a sigma of 0.6 is very suitable for line, space and dense line/space pattern transfer using APSM in this study.
A NEW TECHNIQUE FOR REDUCING THE RESIDUAL-STRESS INDUCED BY WELDING IN TYPE-304 STAINLESS-STEEL
(1995-01-15)
LIN, YC
;
CHOU, CP
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機械工程學系
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Department of Mechanical Engineering
A new Technique named as ''parallel heat welding'' (PHW) is developed for the reduction of residual stress. It is performed by a pair of parallel heating torches attached to the welding torch on both sides as a movable heat source during welding. Autogenous gas tungsten are welding process was used in type 304 stainless steel. The experimental results showed that the maximum principal residual stress and parallel welding direction stress can be reduced by 21-32 % when the conventional welding(CW) process is replaced by the parallel heat welding process. The elevation of equilibrium temperature during welding process is a main mechanism for the reduction of residual stress in PHW process.
ERROR INDUCED BY LOCAL YIELDING AROUND HOLE IN HOLE DRILLING METHOD FOR MEASURING RESIDUAL-STRESS OF MATERIALS
(1995-06-01)
LIN, YC
;
CHOU, CP
;
機械工程學系
;
Department of Mechanical Engineering
The hole drilling strain gauge method described in ASTM standard E837 is a popular method for measuring residual stresses near the surface of a material. However, some measuring errors have been found that may affect the accuracy of the measurement The present paper aims to improve the accuracy by analysing the errors caused by local yielding around the hole. The materials used were 304 stainless steel, 5052 H32 aluminium alloy, and 1018 low carbon steel. The experimental results showed that the error induced by local yielding around the hole is negligible when the residual stresses measured are less than 65% of the yield stress. The maximum errors are in the range 32-47% and occur when the calibrated tensile stress is 95% of the yield stress of the test material. The maximum plastic error occurs in the perfect elastic-plastic material. The plastic error increases as the value of the Young's modulus of the material used increases.
REDUCTION OF RESIDUAL-STRESS BY PARALLEL HEAT WELDING IN SMALL SPECIMENS OF TYPE-304 STAINLESS-STEEL
(1992-02-01)
CHOU, CP
;
LIN, YC
;
交大名義發表
;
機械工程學系
;
National Chiao Tung University
A new method designated 'parallel heat welding' has been developed for the reduction of residual stress in small specimens. It is carried out using a pair of parallel heating torches attached one either side to a welding torch as a movable heat source during welding. Six different welding conditions were applied to an autogenous gas tungsten arc welded Type 304 stainless steel. During welding, the thermal cycles of four locations in the weldment were recorded to investigate the action of thermal stress and to evaluate the effect of the parallel heat sources on sensitisation. In addition, an optical microscope was used to observe the degree of sensitisation. The experimental results show that the maximum principal residual stress and parallel welding direction stress can be reduced by 21-32% when the conventional welding process is replaced by parallel heat welding. The equilibrium temperature of the welded plate can be increased from 45 to 240-degrees-C. Also, based on the exposure time recorded at temperatures in the range 600-850-degrees-C, and metallographical observations, it was found that parallel heat welding has no influence on the degree of sensitisation of austenitic stainless steel weldments.
RESIDUAL-STRESS DUE TO PARALLEL HEAT WELDING IN SMALL SPECIMENS OF TYPE 304 STAINLESS-STEEL
(1992-09-01)
LIN, YC
;
CHOU, CP
;
機械工程學系
;
Department of Mechanical Engineering
The aim of this study was to verify the mechanism of parallel heat welding (PHW) and to investigate the thermal and residual stresses due to welding. In this study, autogenous gas tungsten arc welding was used on type 304 stainless steel. Wells' one-dimensional stress distribution model was assumed to explain the behaviour of stress introduced by conventional welding (CW) and PHW processes. A step by step method proposed by Tall was applied to calculate theoretical thermal and residual stresses. Comparison between experimental and analytical results showed that the predicted results calculated using a modified Wells' model are in agreement with the experimental results, and that the elevation of equilibrium temperature during the welding process is an important mechanism for the reduction of residual stress in the PHW process. The theoretical curves of residual stress calculated for thermal cycles corresponding to CW and PHW processes show fairly good agreement with experimental results in the vicinity of the fusion zone.
The effect of imperfect power control on outage probability in a cellular mobile system
(1995)
LIN, JC
;
LIN, YC
;
LEE, TH
;
SU, YT
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電控工程研究所