Browsing by Author "Hsieh, TE"

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A method to enhance the data transfer rate of eutectic Sb-Te phase-change recording media
(2005-07-15)
Yeh, TT
;
Hsieh, TE
;
Shieh, HPD
;
材料科學與工程學系
;
光電工程學系
This work describes the effect of nitrogen doping to eutectic Sb-Te phase-change materials in order to enhance the speed of the amorphous-to-crystalline phase transformation. When nitrogen at a sputtering gas flow ratio of N-2/Ar=3% was doped in the eutectic Ge-In-Sb-Te recording layer, the data transfer rate was increased up to 1.6 times. When thin GeNx nucleation promotion layers were further added in below and above the recording layer, an overall enhancement up to 3.3 times in data transfer rate was achieved. The nitrogen contents corresponding to the N-2/Ar flow ratios (N-2/Ar=0%-10%) were calibrated by electron spectroscopy for chemical analysis. Transmission electron microscopy revealed that nitrogen doping was able to promote the phase transformation by generating numerous nucleation sites uniformly distributed in the recording layer and hence increased the recrystallization speed. (c) 2005 American Institute of Physics.
A method to enhance the data transfer rate of phase change recording media
(2004)
Yeh, TT
;
Hsieh, TE
;
Shieh, HPD
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Nitrogen doping was applied to enhance the velocity of amorphous-crystalline phase transformation. The nitrogen doping was able to produce tiny nitride precipitates uniformly distributed in the recording layer and provided numerous preferential sites for amorphous-crystalline transition. At the doping condition of N-2/Ar ratio = 3%, the recrystallization velocity of GeInSbTe phase change recording media was increased up to 1.6 times without severely damaging the signal jitter values.
A study of monomer's effect on adhesion strength of UV-curable resins
(2006-10-01)
Chiang, TH
;
Hsieh, TE
;
材料科學與工程學系
;
Department of Materials Science and Engineering
This work studies the effects of the monomer types, the number of hydroxyl functional groups (-OH) on polyol monomers, and the equivalent weight ratio of dicycloaliphatic epoxide to polyol for cationic polymerization (the R value) on the adhesion strength of UV-curable epoxy resins applied to organic light-emitting device (OLED) packaging. It was found that the volume shrinkage of resins after UV curing is related to the crosslinking density of the resin. The smallest volume shrinkage implied the highest adhesion strength of resin on glass substrate since the internal stress was minimized. This study observed that the resin containing polyol monomer is able to achieve the smallest degree of shrinkage (1.72%) and the highest adhesion strength (153.35 kg/cm(2)) on glass substrate. (C) 2005 Elsevier Ltd. All rights reserved.
A study of oxide patterning on titanium thin films using scanning probe microscopy
(2001)
Tsai, HR
;
Hsieh, TE
;
Lo, SC
;
Lin, HH
;
材料科學與工程學系
This work studies the fabrication of oxide patterns on titanium (Ti) thin films using scanning probe microscopy (SPM). We employed three different SPM techniques, namely, AFM in contact mode, lift mode incorporated with contact mode AFM, and STM. It was found that bias voltages.. scanning speed, scanning height of the probe (for lift mode), and setpoint current (for STM) play important roles in forming the attainable oxide features. Among these three methods, contact mode AFM exhibited the best patterning efficiency and stability and this method was adopted to oxidize the I-shaped Ti films. The resistance of I-shaped specimen after anoxidization raised from 10(4)Omega to 10(8)_10(9)Omega which evidenced the occurrence of oxidation in Ti.
Application of A1/PI composite bumps to COG bonding process
(2001-06-01)
Jeng, JH
;
Hsieh, TE
;
材料科學與工程學系
;
Department of Materials Science and Engineering
This work demonstrates the probing, testability and applicability of Al/PI (aluminum/polyimide) composite bumps to the chip-on-glass (COG) bonding process for liquid crystal display (LCD) driver chip packaging. The experimental results showed that the thickness of Al overlayer on PI core of the bump, the location of pin contact, and the bump configuration affect bump probing testability. The bump with type IV configuration prepared in this work exhibited excellent probing testability when its Al overlayer thickness exceeded 0.8 mum. We further employed Taguchi method to identify the optimum COG bonding parameters for the Al/PI composite bump. The four bonding parameters, bonding temperature, bonding time, bonding pressure and thickness of Al overlayer are identified as 180 degreesC, 10 s, 800 kgf/cm(2) and 1.4 mum, respectively. The optimum bonding condition was applied to subsequent COG bonding experiments on glass substrates containing Al pads or indium tin oxide (ITO) pads. From the results of resistance measurement along with a series of reliability tests, Al pad is found to be good substrate bonding pad for Al/PI bump to COG process. Excellent contact quality was observed when the bumps had Al overlayer thickness over 1.1 mum. As to the COG specimens with substrate containing ITO pads, high joint resistance suggested that further contact quality refinement is necessary to realize their application to COG process.
Comparison of characteristics and integration of copper diffusion-barrier dielectrics
(2006-03-01)
Wang, TC
;
Cheng, YL
;
Wang, YL
;
Hsieh, TE
;
Hwang, GJ
The characteristics of various copper (Cu) barrier layers, including SiN, SiCN, and SiCO, were investigated in this work. Carbon-based barrier films (SiCN and SiCO) improved the dielectric constant and line-to-line capacitance, but led to sacrifice in film deposition rate, diffusion-barrier performance, and adhesion strength to Cu in comparison with SiN films. In addition, SiN and SiCO films showed the superior electromigration (EM) performance and stress-induced void migration (SM) performance, respectively. Furthermore, the reliability results of SM and EM are strongly related to the barrier film stress characteristics and the adhesion strength between Cu layers. Therefore, optimization of the barrier layer stress and the enhancement of the interfacial condition between Cu and barrier films are crucial to significantly improve reliability. (c) 2005 Elsevier B.V. All rights reserved.
Copper surface protection with a completely enclosed copper structure for a damascene process
(2004-01-30)
Wang, TC
;
Hsieh, TE
;
Wang, YL
;
Wu, YL
;
Lo, KY
As integrated circuit manufacture moving to copper interconnection for the most advanced products, protection of copper (Cu) surfaces becomes a major challenge for the back-end-of-line manufacturing process. The damages on Cu, such as Cu corrosion and oxidation, are often observed on wafers when exposing bare Cu surface in the presence of moisture and/or acidic gases. Furthermore, the Cu oxide results in poor adhesion both at Cu/barrier layer and Cu/stop layer interfaces. In this work, a novel Cu dual damascene structure which completely encloses the Cu surface with a tantalum nitride layer is presented. This capping layer avoids the Cu corrosion and oxidation due to its ability to keep moisture and acid off and away from the Cu surface. (C) 2003 Elsevier Science B.V. All rights reserved.
Defects in Ge+-preamorphized silicon
(1999-11-15)
Chen, PS
;
Hsieh, TE
;
Hwang, YC
;
Chu, CH
;
材料科學與工程學系
This work studied the morphology and annealing behaviors of extended defects in Si subjected to various Ge+ preamorphization and BF2+ implantation conditions. The extended defects formed were near the specimen surface when Ge+ implantation energy and dose amount were low. During subsequent annealing, the end-of-range (EOR) loops were enlarged and then moved out of the specimen. High energy/low dose Ge+ implantation generated a damaged layer which initially transformed into a wide zone containing dislocation loops and rodlike defects in the annealed specimen. As the annealing proceeded, the width of defective zone gradually shrunk so that most of the extended defects could be annihilated by defect rejection/recombination process. In addition to the category II defects found in previous investigations, hairpin dislocations emerged in high energy/high dose Ge+-implanted specimens. In this specimen, rodlike defects and hairpin dislocations could be removed by annealing, while the EOR loops became relatively inert so that their removal would require high temperatures and/or long annealing times. Microwave plasma surface treatment was also carried out to form a nitride layer on specimen surface. Experimental results indicate that in addition to effectively reducing the size of EOR loops, surface nitridation might serve as a vacancy source injecting vacancies into Si to annihilate the interstitials bounded by dislocation loops. Reduction in the defect size was pronounced when bias voltage was added to the plasma process. However, radiation damage might occur with too high of a bias voltage. (C) 1999 American Institute of Physics. [S0021-8979(99)06322-7].
Development of rewritable dual-layer phase-change optical disks
(2000)
Wu, FH
;
Hsieh, TE
;
Shieh, HPD
;
光電工程學系
;
Department of Photonics
Dual-layer optical disks comprised of two data layers were developed to study readout/write/erase characteristics. This disk was composed of recording layer land 2, of high transmittance and high reflectivity, respectively. Layer 1 and 2 of 15 and 20 nm increase transmittance and reduce writing power for recording. Only 1.5 mW laser power was sufficient for readout, 9 and 16 mW was required for recording on recording layer 1 and 2, respectively. Thse dual-layer disk can double data capacity on a disk substrate.
Direct COSi2 thin-film formation with homogeneous nanograin-size distribution by oxide-mediated silicidation
(2004-09-01)
Chang, JJ
;
Liu, CP
;
Chen, SW
;
Chang, CC
;
Hsieh, TE
By annealing at 460 degreesC for 120 s followed by 600 degreesC 120 s, nanocrystalline CoSi2 thin film with an average grain size of 5 nm can be directly formed from a Co/SiOx/Si multilayer with the SiOx, as a mediated layer. It is found that annealing at 460 degreesC for enough time is crucial for generating enough diffusion channels within the SiOx, layer. After these channels are created, subsequent annealing at 600 degreesC keeps these channels open and is responsible for rapid grain growth. In other words, by using two-step annealing, nucleation and growth processes can be effectively controlled and, hence, the resulting microstructure. The homogeneous nanograin-size distribution is important for ultralarge-scale integration technology below 90 nm to prevent resistance degradation induced by CoSi2, agglomeration. (C) 2004 American Vacuum Society.
Effects of composition on low temperature sinterable Ba-Nd-Sm-Ti-O microwave dielectric materials
(2004)
Cheng, CC
;
Hsieh, TE
;
Lin, IN
;
材料科學與工程學系
;
Department of Materials Science and Engineering
This work investigated the effects of MgO and ZnO additives on the microwave properties of BRT114 = [(BaO.R2O3.4TiO(2)).0.06(2Bi(2)O(3).3TiO(2))] materials. Incorporation of small amount of ZnO (less than or equal to1 wt.%) markedly lowered the temperature coefficient of resonant frequency (tau(f)), to around tau(f) = 1 ppm/degreesC, slightly increased the density and dielectric constant (epsilon(r)) of the materials, but degraded the Q x f factor. Doping 2.5 mol% of MgO, in addition to ZnO, further improved the tau(f)-value for the BRT114 materials. The dielectric constant and the Q x f factor of the materials degrade pronouncedly when doped with too abundant ZnO. Microstructure and EDX analyses indicated that the main factor for degrading the microwave properties is the induction on formation of secondary phases. Moreover, sol gel and fused Ba-B-Si glass reacted with BRT114 in quite a different way. Fused glass wets BRT114 materials more easily than the sol-gel derived glass, resulting in composite materials with higher density and larger dielectric constant. Precalcining the glass-dielectrics mixture, greatly improved the wetting ability of the glass and markedly increased the microwave properties of the glass/dielectric composite, i.e. LTCC materials. (C) 2003 Elsevier Ltd. All rights reserved.
Effects of morphology and surface characteristics of poly(imide siloxane)s and deep UV/O-3 surface treatment on the interfacial adhesion of poly(imide siloxane)/alloy-42 leadframe joints
(1999-07-01)
Jwo, SL
;
Whang, WT
;
Hsieh, TE
;
Pan, FM
;
Liaw, WC
The effect of surface characteristics and morphology of poly(imide siloxane) (PIS) on the true interfacial adhesion between PIS films and alloy-42 substrates was studied. The effect of the viscosity of PIS films and the surface treatment of deep UV/O-3 (d-UV/O-3) on alloy-42 plates on the peel strength of PIS films/alloy-42 joints has also investigated. 3,3',4,4'-benzophenone tetracarboxylic dianhydride/2,2'-bis[4-(3-aminophenoxy)phenyl]sulfone (BTDA/m-BAPS) based PIS films with alpha,omega-bis(3-aminopropyl)polydimethyl siloxane (APPS) molecular weight M-n = 996 g/mole (PIS9Siy) show two phases in all compositions and the linear dependence of the critical surface tension on the surface concentration of the silicon, [Si-surf], on the PIS films. The PIS films with the APPS M-n = 507 g/mole (PIS5Siy) or M-n = 715 g/mole (PIS7Siy) exhibit a morphology change from a homogeneous phase to an inhomogeneous phase starting at the mole ratio (y) of APPS/PIS = 2.7% and 1.1%, respectively. The curves of critical surface tension dependence on the [Si-surf] discontinue or deflect at these two compositions, respectively. The treatment of d-UV/O-3 on alloy-42 plates improves the wetting on the alloy surface and promotes the peel strength between the PIS films and alloy-42 plates by a magnitude of greater than or equal to 20%. These results show that the flowability of the same PIS films bonding at different temperatures significantly affects the bonding strength of the joints, but the flowability of different PIS films bonding at the same temperature, e.g. 400 degrees C, is not the key factor governing the bonding strength of the joints. The true interfacial adhesion of the PIS5Si0.6/alloy-42 joint is 80% higher than that of the unmodified BTDA/m-BAPS based polyimide film/alloy-42 joint. However, zero true interfacial adhesion is obtained between the PIS9Siy films and alloy-42 plates. The wetting kinetics experiment shows that the higher the siloxane content in the PIS, the higher the activation energy for the adhesive bonding process. Moreover, the phase sepration significantly increases the activation energy. The scanning electron micrographs of the peeled-off PIS film surfaces from the PIS/alloy-42 joints reveal the rougher surface morphology from the sample with the higher interfacial adhesion.
Electroless copper/nickel films deposited on AIN substrates
(2004-12-01)
Liang, MW
;
Hsieh, TE
;
Chen, CC
;
Hung, YT
;
材料科學與工程學系
In this work, we studied the application of electroless copper/nickel (Cu/Ni) films deposited on aluminum nitride (AlN) substrates to high-frequency power GaAs device packaging. Experimental results showed metal films deposited on polished AlN surfaces possess a flatter surface, a finer grain structure, and a lower resistivity than those on unpolished surfaces. On unpolished AlN substrates, rough-surface-induced voids appear in the film interface during grain clustering, therefore deteriorating the electrical conductivity of the deposited layers. Pull-off tests revealed that the Cu/Ni films strongly adhered on both types of AlN substrates and that the adhesion strength exceeded 761 kg/cm(2). The Ni film remained a mixture of amorphous and microcrystalline structures, and the Cu film was polycrystalline. The resistivity of the Cu/Ni film was decreased by annealing process, which in turn decreased the number of crystal defects in the films. Subsequent Pb-Sn solder bumping experiments indicated the amorphous Ni(P) film was a good diffusion barrier layer since Sn could not diffuse through it.
Enhancement of data transfer rate of phase change optica disk by doping nitrogen in Ge-In-Sb-Te recording layer
(2004-08-01)
Yeh, TT
;
Hsieh, TE
;
Shieh, HPD
;
材料科學與工程學系
;
光電工程學系
This work investigated the enhancement of the data transfer rate and/or recrystallization speed of Ge-In-Sb-Te recording material by nitrogen doping. The effects of nitrogen content on the dynamic properties of optical disks and the corresponding microstructural changes of the recording layer were studied. The experimental results showed that nitrogen doping at a sputtering gas flow ratio of N-2/Ar = 3% might enhance the data transfer rate of an optical disk up to 1.6 times without severely damaging the signal jitter values. However, the disks failed the dynamic tests when too much nitrogen (N-2/Ar greater than or equal to 5%) was introduced. Dynamic testing also revealed that nitrogen doping slightly increased the noise level and jitter of the disks. Transmission electron microscopy (TEM) found that nitrogen doping promoted a phase transformation by generating numerous nucleation sites uniformly distributed in the recording layer and hence increased recrystallization speed.
Enhancing the overwriting characteristics of phase-change optical disks by doping in dielectric layers
(2004-09-01)
Yu, CH
;
Hsieh, TE
;
Yeh, TT
;
Shieh, HPD
;
材料科學與工程學系
In this work, we studied the enhancement of overwriting characteristics of phase-change optical disks by doping in the dielectric layers. The doping elements included chromium (Cr), molybdenum (Mo), nickel (Ni), tantalum (Ta), titanium (Ti), tungsten (W), vanadium (V), and nitrogen (N-2) Dynamic test showed that doping with a certain amount of W and N-2 in dielectric layers enhanced the disk overwriting characteristics. Up to fortyfold improvement in disk cycleability was observed when N-2 gas was introduced during sputtering deposition of the upper dielectric layer at the gas flow rate of N-2/Ar = 25%. Tungsten was the best among the doping metallic elements resulting in fivefold improvement in disk cycleability. Optical property measurement revealed that the refractive index (n) decreased with increasing N-2 doping percentage, while the relatively small amount of metallic element doping negligibly changed the optical constants. Subsequent modulation simulation showed that such an optical property change is beneficial to disk overwriting characteristics. Nanoindentation test showed that N-2 doping was the most effective method for increasing the hardness of the dielectric layer. This implies that, with increasing mechanical strength, the dielectric layer possesses better resistance to thermal deformation resulting from laser heating, thereby enhancing the cycleability of optical disks.
Initialization characteristics and their effects on the erasability of phase change optical disks using transmission electron microscopy
(1999-03-01)
Chen, HW
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Hsieh, TE
;
Liu, JR
;
Shieh, HPD
;
材料科學與工程學系
We investigated the microstructure of phase change optical disks subjected to various initialization conditions using transmission electron microscopy (TEM). The effects of initialization powers on the erase ratio of phase change optical disks and corresponding microstructure changes were also studied. It was found that the increase of initialization power enlarged the width of the recrystallization band formed in the recording media of the disk. A wide recrystallization band was effective for decreasing the residual signal level hence the erase ratio increased. Disk dynamic test and TEM study results also revealed the deterioration of carrier-to-noice ratio (CNR) characteristic and the increasing trend of erase ratio was reduced when a substantial amount of coarse grains appeared in the crystalline region. This elucidates the necessity for phase change optical disks to have good heat dissipation property in order to suppress the formation of coarse granular structures.
Mask films for thermally induced superresolution readout in rewritable phase-change optical disks
(2001-03-01)
Lu, YH
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Dimitrov, D
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Liu, JR
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Hsieh, TE
;
Shieh, HPD
Tellurium was studied as a mask film in a thermally induced superresolution rewritable optical disk for detecting below-diffraction-limit marks. Mark trains of 0.15 mum could be retrieved with 9 dB in carrier-to-noise (CNR) using an optical system with the laser wavelength of 780 nm and an objective lens of 0.55 numerical aperture. Readout cyclability was examined and methods to further improve readout cyclability were proposed.
Mechanical properties of clay-polyimide (BTDA-ODA) nanocomposites via ODA-modified organoclay
(2000-11-15)
Tyan, HL
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Wei, KH
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Hsieh, TE
;
材料科學與工程學系
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Department of Materials Science and Engineering
Clay-polyimide [3,3', 4,4'-benzophenone tetracarboxylic dianhydride-4,4'-oxydianiline (BTDA-ODA)] nanocomposites were synthesized from ODA-modified montmorillonite (organoclay) and poly(amic acid). The layered silicates of organoclay were intercalated by polyimide (BTDA-ODA), as confirmed by X-ray diffraction and by transmission electron microscopy, and the tensile mechanical properties of the nanocomposites were measured. It was found that the modulus and the maximum stress of these organoclay/BTDA-ODA nanocomposites were much higher than those of pure BTDA-ODA: a twofold increase in the modulus and a one-half-fold increase in the maximum stress in the case of 7/93 organoclay-BTDA-ODA. In addition, the elongation-for-break of organoclay/BTDA-ODA nanocomposites is even slightly higher than that of pure BTDA-ODA, which is a sharp contrast to that of conventional inorganics-filled polymer composites. (C) 2000 John Wiley & Sons, Inc.
Microwave dielectric properties of glass-ceramic composites for low temperature co-firable ceramics
(2003)
Cheng, CC
;
Hsieh, TE
;
Lin, IN
;
材料科學與工程學系
;
Department of Materials Science and Engineering
Ba-B-Si glass was added to Ba-Nd-Sm-Bi-Ti-O (BRT114) microwave dielectric material for LTCC applications. Conventional one-step processing method for preparing glass-BRT114 composite materials yields low dielectric constant, since the glass was easy to react with BRT114 and forms a low dielectric constant phase, Ba3B6Si2O16. A large proportion of pores appeared. The nature of glass, whether it is sol-gel derived or fused, shows marked influence on the microstructure and microwave dielectric properties of the composites. A two-step process containing precoating the BRT114 powders with a thin layer of glass, followed by conventional samples preparation process, tremendously improved the densification behaviour of the material. The formation of pores and interactions between glass and BRT114 was greatly suppressed such that materials with high dielectric constant (epsilon(r) = 40) were achieved by sintering 9 wt.% glass-containing composite at 950 degreesC for 2.5 h. (C) 2003 Elsevier Ltd. All rights reserved.
Modified polycrystalline silicon chemical-vapor deposition process for improving roughness at oxide/polycrystalline silicon interface
(2005-01-24)
Chang, JJ
;
Hsieh, TE
;
Wang, YL
;
Tseng, WT
;
Liu, CP
A new modified low pressure chemical-vapor deposition process for stacked polysilicon (poly-Si) films is developed in this study. The proposed stacked film process combines polysilicon with amorphous silicon films. In this process, polysilicon film was deposited first at 630degreesC, followed by a continuous temperature decrease down to 560degreesC for the deposition of amorphous silicon film. It was found that the doped stacked polysilicon films deposited by this process result in lowering of surface roughness, together with reduction of the (311) phase of the doped amorphous silicon and (110) phase of the doped polysilicon. As a consequence, device performance based on the stacked films also improves. Results of surface roughness analysis indicated that the doped stacked polysilicon film has a root-mean square surface roughness (Rrms) of 78 A, which is smaller than those of doped conventional (630degreesC) polysilicon film (Rrms=97 A), and doped amorphous silicon film (Rrms=123 A, deposited at 560degreesC). Transmission electron microscopic (TEM) observation performed at oxide/polysilicon interface showed that the conventional (630degreesC) oxide/polysilicon interface has high angle grain boundaries on the polysilicon side, which may induce leakage current around the interfacial area. (C) 2004 Elsevier B.V. All rights reserved.