bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Anodic Electrodeposition Coating on the Structure of Three-Step Coloring Films on Aluminum
Authors: Yamamuro Masaaki , Morisaki Shigeyoshi
Published: October 2002

Three-step electrolytic coloring of aluminum was carried out by applying sulfuric acid, low-voltage AC anodic oxidization between DC anodic oxidization and electrolytic coloring. The films produced by this three-step electrolytic coloring method were observed using a transmission electron microscope (TEM) and a scanning electron microscope (SEM) to study the influence of anodic electrodeposition (ED) coating on the film structure. AC electrolysis following DC anodic oxidization showed the current recovery phenomenon, and an AC anodizing layer was generated under the DC anodizing layer with the barrier layer remaining. In addition, the thickness of the barrier layer of the AC anodizing layer indicated the simultaneous progress of the metal compound deposit reaction and the formation reaction of the barrier layer for electrolytic coloring. The ED coating did not affect the structure of each anodizing layer greatly, nor did it affect the metal compound deposited in the AC anodizing layer, but the metal compound that was previously deposited unevenly in the DC anodizing layer could no longer be observed using a TEM. The discoloration of the electrolytic colored film with ED coating may not be attributable to a change in the interference distance due to elution of the deposits in the AC anodizing layer or to a change in the thickness of the barrier layer, but rather to a change in the conditions of the metal compound deposited in the DC anodizing layer.
Effect of Aluminum Seed Layer on the Crystallographic Texture and Electromigration Resistance of Physical Vapor Deposited Copper Interconnect
Authors: Chin Yu-Lung , Chiou Bi-Shiou , Wu Wen-Fa
Published: October 2002

The effects of an Al underlayer with respect to texture control and electromigration (EM) resistance of Cu films are investigated in this study. The Al underlayer enhances the (111) texture of Cu films and the surface smoothness of the annealed Cu film. The same cubic crystal structure (face-centered cubic) and small difference of the nearest interatomic distance of the (111) plane between Cu and Al result in the increase of the peak ratio I
(111)/I
(200) of Cu films. The thicker the Al film, the more preferred the Cu (111) orientation. The resistivity of the Cu/Al bilayer film, which increases at about 0.2 µΩ·cm per 1-nm-thick Al underlayer, is smaller than the reported value of single phase Cu(Al) solution. The EM resistance of Cu interconnects is also improved when the Al underlayer is present. The mean time to failure (MTF) of Cu interconnects with a 5-nm-thick Al underlayer is longer by one order of magnitude than that without an Al underlayer at 240°C and 12 MA/cm2.
Stacking of a Low Current Electron Beam in a Harmonic Potential Trap by RF-Repeller
Authors: Akihiro Mohri Akihiro Mohri , Tetsumori Yuyama Tetsumori Yuyama , Hitoshi Tanaka Hitoshi Tanaka , Hiroyuki Higaki Hiroyuki Higaki , Yohei Yamazawa Yohei Yamazawa , Toshinori Michishita Toshinori Michishita
Published: October 2002

Particles of a low current beam can be accumulated in a harmonic potential well in a high vacuum environment when they are repelled back by a local rf electric field of the frequency close to the bounce motion in the well. Here, proper damping mechanisms for the repelled particle blobs are necessary to suppress their bounce motions. This stacking method was experimentally proved for electron beams of 1.1 µA using a Multi-Ring-Electrode trap and the results were compared with numerical estimations based on a single particle model. The observed damping was much larger than the estimated one from the resistive wall effect. The stacking efficiency was nearly the same as the estimated one at the stacked number N less than 1×107 but it decreased with N. Experimentally obtained relationship amongst the stacked number, the incident beam energy, the rf frequency and its amplitude behaved qualitatively in the same way as the numerical results. The accumulation proceeded until the well was filled up with electrons.
An Investigation of Nonuniform Deposition of Field Emission Displays Phosphors on Unbiased Indium-Tin-Oxide Coated Glass During Electrophoresis
Authors: Shin Sang Hoon , Jeon Duk Young , Jin Yong Wan , Kim Jong Min
Published: October 2002

Upon the deposition of field emission displays (FED) phosphors in electrophoresis, a weak and nonuniform deposition of phosphor on the unbiased neighbor indium-tin-oxide (ITO) patterns is always observed in addition to the expected thick and uniform deposition of phosphor on the biased patterns. An explanation of the origin of the nonuniform deposition is attempted by solving Laplace's equation with proper boundary conditions simulating the deposition bath used for the sample preparation. According to the solution of Laplace's equation, in the beginning, the potential distribution is such that the electric field has a parallel component from the unbiased ITOs to the biased ones in addition to the major vertical components of the electrical field. However, during the deposition, the field has the parallel component from the biased ITOs to the unbiased ones as the thickness of the deposited phosphor increases. This appears to generate the observed nonuniform deposition on the unbiased ITO patterns.
Anharmonic Effective Pair Potentials of γ- and α-CuBr at High Pressure
Authors: Yoshiasa Akira , Okube Maki , Ohtaka Osamu , Kamishima Osamu , Katayama Yoshinori
Published: October 2002

The anharmonic effective pair potentials V(u)=a
u
2/2+b
u
3/3!+c
u
4/4! for Br–Cu bond in γ- and α-CuBr under pressure have been investigated by an extended X-ray absorption fine structure (EXAFS) technique. The EXAFS spectra near the Br K-edge were measured under high temperature and high pressure using a large-volume uniaxial press and synchrotron radiation from SPring-8. In the parameter fitting process, we have directly carried out the numerical integration of the EXAFS function and evaluated the precise anharmonic effective pair potentials. The anharmonic effective pair potential for each phase is influenced by pressure and becomes steeper with increasing pressure. The potential parameter a for γ-phase at 0.1 MPa increases by about 20% at the pressure of 4.8 GPa. The Grüneisen parameters γG for γ-CuBr are calculated from the obtained values of a and b as 1.4 and 1.6 at 0.1 MPa and 4.8 GPa, respectively. The fourth order term in the potential parameter is significant in α-CuBr at 7.0 GPa. The effective pair potentials do not change appreciably through the phase transition from γ to α-phase. The statistical distribution of Cu in α-CuBr and superionic conduction mechanism have been discussed based on the effective pair potential and distribution of Br–Cu distances. The probability of finding mobile Cu ions at the saddle-point position is several percent at 7.0 GPa and 1200 K in the superionic conducting α-CuBr.
Crosstalk in Photoluminescence Readout of Three-Dimensional Memory in Vitreous Silica by One- and Two-Photon Excitation
Authors: Mitsuru Watanabe Mitsuru Watanabe , Saulius Juodkazis Saulius Juodkazis , Shigeki Matsuo Shigeki Matsuo , Junji Nishii Junji Nishii , Hiroaki Misawa Hiroaki Misawa
Published: October 2002

We report the readout of three-dimensional (3-D) memory of bits from their photoluminescence (PL). The bits were recorded inside vitreous silica by optical damage (micro-explosion), which was induced by 150 fs single pulse irradiation at the focal point. The bit can be written by 0.2–0.5 µJ energy pulses at 400 nm or 800 nm (the pulse energy was given at the irradiation point and had an intensity of about 1015 W/cm2 when a high numerical aperture of NA = 1.3 objective lens was used for recording). The readout was obtained by the PL of the 3-D pattern of damaged bits, which were excited by quasi-continuos (repetition rate of 82 MHz) fs-irradiation at much lower pulse intensity (by a factor of 106) in order to exclude secondary damage. The readout was performed by the oil-immersion objective lens of NA = 1.3. The wavelength of PL excitation was 400 nm for one-photon and 800 nm for two-photon excitation of PL with the single pulse energy of less than 1 pJ. We found that the crosstalk of PL readout is the same as that for the transmission imaging and measures 4 µm in the inter-plane distance for the case of one-photon excitation and can be reduced to 3 µm when a reflection-type readout system is used together with two-photon excitation (theoretical axial bit size for fabrication of a given optics was 1.4 µm). Two-photon readout of 3-D memory in silica is demonstrated for the first time.
A Novel Approach of Inductance Matrix Inversion in Induction Motor Digital Simulation
Authors: Yang Zhong-jing , Li Chuan-xin , Zhang Ping-hui , Zhao Ran-hang
Published: October 2002

Owing to the fact that the inductance matrix of a three-shape induction motor is
a cycle matrix and the characteristics of this cycle matrix combinations are valid, it is
preferable to derive correlative expressions between the inductance matrix and its
inverse to obtain the result in a straightforward manner by assignment instead of
calling subroutines for saving much computation time. The computation time required
by this approach is compared with that required by the coordinate transformation
method. A new approach different from the conventional method is proposed. On the
basis of the fact that the inductance matrix in a three-shape induction motor is a cycle
matrix, an expression for the inductance inverse matrix is acquired. Thus repetitive
inverse operations are replaced with straightforward assignment. It is proved via
practical examples that this method not only avoids complex conversion of coordinates
but also decreases calculation time.
Experimental Results Obtained using Extreme Ultraviolet Laboratory Tool at New SUBARU
Authors: Kinoshita Hiroo , Watanabe Takeo
Published: October 2002

We have designed three-aspherical-mirror optics that meets the specifications for 0.1 µm generation lithography, and are developing an extreme ultraviolet lithography (EUVL) laboratory tool suitable for device fabrication experiments. It operates at a wavelength of 13.5 nm and employs a three-mirror imaging system with a numerical aperture of 0.1. It is capable of replicating 65 nm patterns in an exposure field of 30 mm×1 mm size. First, single-layer chemically amplified resists are investigated using the synchrotron radiation (SR) source of New SUBARU. From the sensitivity curve, it was found that the positive-tone resist DP603 and the negative-tone resist SAL601 have high gamma values and high sensitivities to the extreme ultraviolet exposure wavelength. Furthermore, exposure experiments using the three-aspherical mirror imaging system were performed. A minimum line width of 56 nm was demonstrated in an exposure area of 10 mm×1 mm. We confirmed that the three-aspherical mirror imaging system is useful for developing EUVL technology.
Application of Organic Silicon Clusters to Pattern Transfer Process for Deep UV Lithography
Authors: Sato Yasuhiko , Shiobara Eishi , Abe Junko , Onishi Yasunobu , Yoshikawa Sawako , Nakano Yoshihiko , Hayase Shuji
Published: October 2002

A pattern transfer process using organic silicon clusters (OSCs) as bottom antireflective coating (BARC) for deep UV (DUV) lithography is introduced to realize high antireflective performance and efficient etch properties simultaneously. Unlike linear polysilanes, OSC has three-dimensional quaternary Si atoms (cluster units called Q units). It can be simply spin-coated and lowers the cost of ownership. Its refractive index at 248 nm is n=1.80 and k=0.30, and the intrinsic reflectivity is greatly reduced to 0.6%. Etch selectivity of BARC/resist is 3.3, which is much higher than that of the conventional organic BARC, namely, ∼1. OSC can also act as an adequate etch mask: etch resistance is 1.1 times greater than that of the resist and it is not denatured during substrate (dielectrics) etching. In comparison with the conventional organic BARC process, the OSC's excellent etch properties reduce resist thickness required to etch a substrate by approximately 270 nm, which enlarges the lithographic process window.
Theoretical Calculation of Mask Error Enhancement Factor for Periodic Pattern Imaging
Authors: Terasawa Tsuneo , Hasegawa Norio
Published: October 2002

The mask error enhancement factor (MEF) is analyzed through an imaging theory, and simple equations for finding the MEFs for partially coherent imaging are developed. Periodic line pattern images projected by an alternating phase shift mask (PSM), an attenuated PSM, and a binary mask were evaluated under several illumination conditions and the MEF for each set of mask exposure conditions was predicted using these simple equations. With a binary mask or attenuated PSM, three-beam interference imaging for equal lines and spaces was found to provide an MEF of 0.5, while the two-beam interference provided an MEF of 1.0 due to the absence of -1st or +1st order diffracted waves. When the ratio of illumination components to eliminate both the -1st and +1st order diffracted waves increased due to fine features, the MEF increased dramatically. On the other hand, the MEF of an alternating PSM was found to be 1 under two-beam interference for projecting equal lines and spaces, and increased when the -1st or +1st order diffracted wave was eliminated. Our results suggest that the phase edge PSM should be advantageous because the MEF can be reduced to less than 0.5.
Growth and Characterization of KMgF3 Single Crystals by the Czochralski Technique under CF4 Atmosphere
Authors: Shimamura Kiyoshi , Fujita Tomoyo , Sato Hiroki , Bensalah Amina , Sarukura Nobuhiko , Fukuda Tsuguo
Published: October 2002

KMgF3 (KMF) single crystals were grown by the Czochralski technique as a new candidate of vacuum-ultra-violet optical materials. The absorption edge of KMF single crystals was 115 nm. The distribution of birefringence in the radial direction was of the order of 10-7. The thermal expansion coefficient of KMF single crystals along the <111> orientation was 1.98×10-5 K-1. Together with its excellent mechanical properties, these characteristics show KMF to be superior to the current materials.
Precise Delineation Characteristics of Advanced Electron Beam Mask Writer EB-X3 for Fabricating 1× X-Ray Masks
Authors: Shinji Tsuboi Shinji Tsuboi , Hiroshi Watanabe Hiroshi Watanabe , Mizunori Ezaki Mizunori Ezaki , Hajime Aoyama Hajime Aoyama , Yukiko Kikuchi Yukiko Kikuchi , Yoshinori Nakayama Yoshinori Nakayama , Shigehisa Ohki Shigehisa Ohki , Toshifumi Watanabe Toshifumi Watanabe , Tetsuo Morosawa Tetsuo Morosawa , Kenichi Saito Kenichi Saito , Masatoshi Oda Masatoshi Oda , Tadahito Matsuda Tadahito Matsuda
Published: October 2002

This paper discusses the delineation characteristics of a state-of-the-art variable-shaped electron-beam (e-beam) mask writer called the EB-X3, which was developed both to write 100-nm-node patterns on X-ray membrane masks and also to study the feasibility of the mask technology. For a 1-Gb dynamic random access memory (DRAM) pattern (22 mm×22 mm chip), the best image placement (IP) accuracy obtained so far is 3σ(X, Y) = (5.6 nm, 8.4 nm) and maximum Δ(X, Y) = (4.2 nm, 7.3 nm). IP values less than 15 nm are reproducible. Precise temperature control and a three-point support pallet (4-inch membrane warpage: <100 nm) are the keys to this excellent IP. A resolution of 50 nm was obtained for line-and-space patterns. Good critical dimension control of less than 10 nm and small proximity effects were obtained with ZEP resist and normal-hexyl acetate developer. A total overlay accuracy for proximity X-ray lithography of better than 40 nm was achieved at the 1-Gb-DRAM level using X-ray masks with a 19-nm overlay accuracy (gate to contact) fabricated using the EB-X3.
A New Cleaning Technique for X-Ray Masks in Alkaline Solutions by Direct Control of Electrochemical Potential
Authors: Tuda Mutumi , Kinugawa Masaru , Ootera Hiroki , Marumoto Kenji
Published: October 2002

This paper describes an electrochemical surface cleaning (ECSC) technique newly developed for removal of particulate contamination on X-ray masks employing WN
x
absorbers. In this technique, the electrochemical potential of absorber films is precisely controlled for preventing corrosion or etching of the films during their immersion in alkaline solutions. The particle removal efficiency and the stress change of WN
x
absorbers were examined and compared with those after the conventional cleaning operated under electrically floating condition. The etched depth (and thus etch rate) of WN
x
films in alkaline solutions was measured using an in-situ quartz-crystal-microbalance technique. Furthermore, X-ray photoelectron spectroscopy and atomic force microscopy were employed to characterize WN
x
film surfaces. Mechanisms responsible for a large stress change observed in the case of conventional cleaning are discussed. Moreover, it is demonstrated that the ECSC operated at cathodic potentials yields high removal efficiencies for a variety of particulates without change in film thickness and stress between before and after cleaning.
Patterning Yield of Sub-100-nm Holes Limited by Fluctuation of Exposure and Development Reactions in Synchrotron Radiation Lithography Using Biased Mask Patterns
Authors: Deguchi Kimiyoshi , Kawai Yoshio , Kochiya Hiroyuki , Ushiyama Yukihiko , Oda Masatoshi
Published: October 2002

In this article, we evaluate the patterning yield of sub-100-nm holes limited by the fluctuation of exposure and development reactions in synchrotron radiation (SR) lithography, particularly with the use of biased mask patterns. By increasing the exposure dose as a parameter, yield versus exposure dose and yield versus pattern size for both chemically amplified and conventional resists are investigated under various conditions of exposure and development. By estimating the number of photons contributing to the photochemical reactions in each hole, it is shown that the fluctuation of the absorbed photons is a primary factor limiting the patterning yield around the threshold exposure dose. Improvement of the yield for very fine patterns around the diffraction-limited resolution (50 nm) will be discussed.
Mask Error Factor in Proximity X-Ray Lithography
Authors: Fujii Kiyoshi , Suzuki Katsumi , Matsui Yasuji
Published: October 2002

We discuss the mask error factor (MEF) in proximity X-ray lithography. The MEFs for dense-line, isolated-line, and isolated-hole patterns were estimated by using aerial image simulations and exposure experiments. When the minimum feature size was 100 nm, MEFs in the patterns were kept within unity by setting the proximity gap to 15 µm. For feature sizes of 70 nm, the proximity gap should be reduced to as small as 10 µm to maintain the MEF at around unity for dense- and isolated-line patterns. For isolated-hole patterns, a high-resolution resist with a shorter acid-diffusion length (<20 nm) should be used to keep the MEF at around unity. The MEF changes depending on geometric conditions, such as the pattern size, proximity gap, X-ray wavelength, and absorber thickness. The MEF is determined mainly by the interference between the diffracted X-rays, which have different phases. Thus, the MEF can be controlled by choosing the appropriate exposure conditions. In most cases, the MEF in proximity X-ray lithography is much smaller than that in optical lithography, which is advantageous for the proximity lithography because it allows a larger margin in the critical dimension control for 1X X-ray masks.
Sub-100-nm Device Fabrication using Proximity X-Ray Lithography at Five Levels
Authors: Iba Yoshihisa , Taguchi Takao , Kumasaka Fumiaki , Iizuka Takashi , Sambonsugi Yasuhiro , Aoyama Hajime , Deguchi Kimiyoshi , Fukuda Makoto , Oda Masatoshi , Morita Hirofumi , Matsuda Tadahito , Horiuchi Kei , Matsui Yasuji
Published: October 2002

We applied proximity X-ray lithography at five levels (mark, isolation, gate, contact and wiring) to fabricate devices at a scale of 100 nm and lower. Low-contrast masks and chemically amplified resists were used, and a critical dimension (CD) variation (3σ) within 10% of the pattern width at a scale of 100 nm was obtained at each layer. The resolution remained good down to 80 nm isolation gates at a gap of 15 µm. Overlay accuracy (mean±3σ) at each layer was within 40 nm, especially at the contact-hole layer which was below 25 nm. We evaluated the fabricated device performance for subthreshold characteristics, hot-carrier reliability and threshold voltage fluctuations. Good characteristics were obtained for n-channel metal oxide semiconductor field effect transistor (n-MOSFET) devices that scale into the 100 nm regime. In this paper, we demonstrate the feasibility of X-ray lithography in process for 100-nm-and-lower devices.
Progress in Top Surface Imaging Process
Authors: Satou Isao , Watanabe Manabu , Watanabe Hiroyuki , Itani Toshiro
Published: October 2002

A top surface imaging (TSI) process is one of the approaches for 0.10 µm or smaller pattern fabrication using photolithography. We have been evaluating the different types of bilayer resist processes, such as a bilayer silylation process, a bilayer process using a Si-containing resist and an improved silylation process which applies vapor phase silylation treatment after alkaline wet development (SILYAL). In this paper, we review the current status of these processes, specifically focusing on the progress in the bilayer silylation process. In addition, we evaluated the critical dimension (CD) controllability of the bilayer silylation process for 193 nm lithography and found that this process can already be compared with the wet-development single-layer resist process. We found that the resist stripping technique, which has been the main problem of the TSI process, is practically feasible with the application of a plasma ashing treatment followed by a subsequent wet cleaning using a fluorine-containing chemical stripper. We also evaluated the characteristic properties using a 157 nm frame exposure tool and confirmed that this process is extendible to 157 nm lithography.
RF-Plasma-Assisted Fast Atom Beam Etching
Authors: Ono Takahito , Orimoto Norimune , Lee Seungseoup , Simizu Toshiki , Esashi Masayoshi
Published: October 2002

A fast atom beam (FAB) source used for dry etching is capable of high anisotropy etching because it utilizes neutral etching species. However, the kinetic energy of the FAB is high (normally above 1 keV), therefore, selectivity is diminished due to the spattering effect of the atom beam; also, etching damage is caused on the surface of the sample specimen. We propose and have fabricated a radio-frequency (RF) plasma-assisted FAB source, which can produce a low-energy FAB. A conventional FAB source generates plasma inside a cathode tube by applying a high voltage between the cathode and an anode situated in the tube. The energy of the FAB is almost proportional to the anode voltage. The new FAB source consists of a conventional FAB source and a helicon plasma cell to assist the generation of plasma and increase the plasma density in the cathode tube. Therefore, plasma is generated at a relatively low voltage (from 50 V to 1 kV). Using this FAB source, the preliminary performance, such as the etching rate and the damage caused on the silicon surface, is investigated.
In–situ Time–Resolved Infrared Spectroscopic Study of Silicon–Oxide Surface during Selective Etching over Silicon in Fluorocarbon Plasma
Authors: Ishikawa Kenji , Sekine Makoto
Published: October 2002

We investigated how fluorocarbon (CF) film formation evolves from the beginning of the etching process and how it reaches a steady state at a specific thickness. Using in–situ time–resolved infrared spectroscopy with attenuated total reflection method, we measured the spectra every 2 s and observed CF film formation during plasma etching of silicon oxide. The observed spectra overlapped: a band at around 1200–1400 cm-1 caused by CF bonds overlapped with a trough at below 1300 cm-1 caused by silicon oxygen bonds. By deconvolving each component of the spectra in the series, we obtained the time–resolved intensity profiles. We found that the CF film was deposited and that its thickness reached a steady state during etching. The time evolution was fitted by a model based on the balance of rates between deposition and sputtering of the CF film.
Effect of Multipulse Waveform on Gains of Soft X-Ray Lines of Lithium-Like Aluminum Ions in Recombining Plasmas
Authors: Okasaka Kazunobu , Kawachi Tetsuya , Oyama Hitoshi , Hara Tamio , Yamaguchi Naohiro , Ando Kozo
Published: October 2002

Using the recombination plasma scheme, we investigated the
amplified spontaneous
emissions (ASE) from lithium-like aluminum plasmas produced by
multipulse laser
irradiation. Three types of multipulse waveforms of Nd-glass laser
beam were treated.
We measured the time-integrated intensities of the 3d–4f (15.5 nm) and
the 3d–5f (10.6 nm) lines of lithium-like aluminum ions for
2.5-cm-long and
1.25-cm-long plasmas.
The effective time-averaged gains estimated from these time-integrated
intensities
varied with the multipulse waveforms. Using a hydrodynamic
simulation, we
discussed the time history of plasma parameters in the recombining
plasma. We
concluded that the modifying multipulse waveform contributed to the
effective time-averaged gain by maintaining the helium-like ion
density until the gain was generated.
Amelioration of the Interfacial Properties in Au/GaAs Schottky Contact Using Sulfidation and Hydrogenation
Authors: Min-Gu Kang Min-Gu Kang , Ji-Wan Kim Ji-Wan Kim , Hyung-Ho Park Hyung-Ho Park
Published: October 2002

We report on a novel passivation method of GaAs with sulfidation and hydrogenation, fabricating Au/GaAs interface free of defective interfacial bonds and ultimately improving the electrical property of its Schottky contact. In this study, the realistic bonding features of GaAs surface/interface were directly monitored using high resolution X-ray photoelectron spectroscopy and the electrical properties were evaluated with current–voltage (I–V) method. Sulfur-passivation with (NH4)2S solution, as surface treatment of GaAs, was effective to make Au/GaAs interface completely free of GaAs oxides, while the presence of interfacial excess As originated from Au metallization was unavoidable. To control this defective As compound, we introduced hydrogen-plasma treatment after deposition Au film to S-passivated Schottky diode. The S-passivated and successive hydrogenated Au/GaAs interface showed only non-defective interfacial compound of Ga sulfide, free of any defective bonding state, since interfacial excess As seemed to effectively sublimate by forming volatile As hydride. With complete absence of interfacial excess As, the reverse leakage current of its Schottky diode was dramatically reduced about ten times, compared with only S-passivated sample. From capacitance–voltage (C–V) dopant profile, this two-step method was found to have no damage into GaAs substrate due to the barrier effect of pre-coated Au layer on GaAs surface.
Effects of H2 Addition in Magnetized Inductively Coupled C2F6 Plasma Etching of Silica Aerogel Film
Authors: Seok-Joo Wang Seok-Joo Wang , Hyung-Ho Park Hyung-Ho Park , Geun-Young Yeom Geun-Young Yeom
Published: October 2002

Effect of H2 addition to C2F6 plasma etching of SiO2 aerogel film was examined for low-k dielectric application. In this experiment, H2 plasma in itself was responsible for pore blocking and bond breaking of the SiO2 aerogel. With increasing hydrogen from 0 to 50%, etch rate of SiO2 aerogel was severely dropped at 20% of H2 addition. According to the increase in H2 addition, transition from fluorine-rich residue to carbon-rich one was gradually happened in SiO2 aerogel. Surface microstructure of SiO2 aerogel was so influenced with the increasing H2 addition that they transformed to be planar by the interaction between residue/network and ion bombardment and the condensation reaction of surface chemicals with H2 plasma.
Si Barrier Metal Growth by Hybrid Radical Beam-Pulsed Laser Deposition of TiN
Authors: Obata Kotaro , Sugioka Koji , Toyoda Koichi , Takai Hiroshi , Midorikawa Katsumi
Published: October 2002

Hybrid radical beam-pulsed laser deposition (PLD) of titanium nitride (TiN) has been demonstrated for the growth of Si barrier metal. A combination of PLD and nitrogen radical beam has grown high-quality TiN films on Si(100) substrate without silicidation at the interface between the TiN thin film and Si substrate. Additionally, silicidation was suppressed even at growth temperatures up to 900°C. Diffusion barrier characteristics of the grown film were examined by the deposition of aluminum (Al) thin films of about 400 nm thickness on the TiN grown films, followed by post-thermal treatment at 500°C for 30 min. Scanning electron microscopy (SEM) observation and Rutherford backscattering spectroscopy (RBS) analysis revealed that sharp interfaces of both Al/TiN and TiN/Si were maintained after the thermal treatment, indicating excellent properties of the TiN films as a Si barrier metal.
Dynamic Three-Dimensional Mask-Wafer Positioning with Nanometer Exposure Overlay
Authors: Moon Euclid E. , Meinhold Mitchell W. , Everett Patrick N. , Smith Henry I.
Published: October 2002

We describe a means of dynamically controlling the relative mask-wafer position in X, Y, and Z during proximity X-ray exposures. The axis of a point X-ray source is detected by a direct X-ray obscuration scheme. Point-source-induced exposure runout is controlled to <1 nm along the source axis. Nanometer exposure overlay is measured by the spatial phase of fringes in resist, observed with a separate, normal-incidence microscope. These aligning and gapping techniques, in combination with the method of aligning the axis of a point X-ray source to a fiducial point on the mask, result in a minimum controlled exposure overlay of 2.5 nm.
Collapse Behavior of KrF Resist Line Pattern Analyzed with Atomic Force Microscope Tip
Authors: Kawai Akira
Published: October 2002

A quantitative analysis of the adhesion property of a KrF line resist pattern of 170 nm width is carried out experimentally. By directly applying load to the top corner of the resist pattern with a microcantilever tip, a resist line pattern adhering on a substrate can be collapsed easily and is accompanied by residue formation. The dependency of line pattern collapse on load position along with line direction is investigated. At the load position 3 µm away from the pattern edge, the average load required for the pattern collapse is about 15 times larger than that of the load position at the pattern edge. Based on this result, one can confidently state that the pattern edge is more likely to collapse. In combination with the analysis of the internal stress distribution of the resist pattern, the load position dependency of the pattern collapse and the destruction mechanisms of the resist-substrate interface can be clarified. It is also clear that the crack formed at the pattern bottom affects the stress concentration and the residue shape.
Fabrication of a New Electrostatic Linear Actuator
Authors: Matsunaga Takashi , Kondoh Kazuya , Kumagae Michihiro , Kawata Hiroaki , Yasuda Masaaki , Murata Kenji , Yoshitake Masaaki
Published: October 2002

We propose a new electrostatic linear actuator with a large stroke and a new process for fabricating the actuator. A moving slider with many teeth on both sides is suspended above lower electrodes on a substrate by two bearings. A photoresist is used as a sacrificial layer. Both the slider and the bearings are fabricated by Ni electroplating. The bearings are fabricated by the self-alignment technique. Bearings with 0.6 µm clearance can be easily fabricated. All processes are performed at low temperatures up to 110°C. It is confirmed that the slider can be moved mechanically, and also can be moved by about 10 µm when a voltage pulse of 50 V is applied between the slider and the lower electrodes when the slider is upside down. However, the slider cannot move continuously because of friction. We also calculate the electrostatic force acting on one slider tooth. The simulation result shows that the reduction of the electrostatic force to the vertical direction is very important for mechanical movement of the actuator.
Novel Micromachined Coplanar Waveguide Transmission Lines for Application in Millimeter-Wave Circuits
Authors: Park Jae-Hyoung , Baek Chang-Wook , Jung Sanghwa , Kim Hong-Teuk , Kwon Youngwoo , Kim Yong-Kweon
Published: October 2002

In this paper, novel micromachined coplanar waveguide(CPW) transmission lines for application in millimeter-wave circuits are proposed. Two types of transmission lines with the length of 1 cm are fabricated and the measured characteristics are compared with those of the conventional CPW transmission line. One is the elevated CPW(ECPW) transmission line and the other is the overlay CPW(OCPW) line. These transmission lines are composed of 3-µm-thick electroplated gold lines with overhanging parts. By elevating the metal lines from the substrate using micromachining technology, the conductor and substrate dielectric loss can be reduced and easily integrated with conventional monolithic microwave integrated circuits. Compared with the conventional CPW line showing 2.65 dB/cm insertion loss at 50 GHz, the loss can be reduced to 1.9 dB/cm and 1.25 dB/cm at 50 GHz in the case of the ECPW and OCPW transmission lines, respectively. Also, the OCPW transmission line shows that the insertion loss does not vary with the change of the characteristic impedance. As shown in the measured and simulated results, the insertion loss is maintained below 1.4 dB/cm over wide impedance ranges.
3D Thermoelectric Structures Derived from a New Mixed Micromachining Process
Authors: Du Chen-Hsun , Lee Chengkuo
Published: October 2002

This paper proposes an innovative 3D thermoelectric structure which significantly reduce the componet size without deterioration of sensor performance. Based on complementary metal-oxide-semiconductor (CMOS) transistor compatible process, this 3D thermoelectric structure is demonstrated and fabricated by combining front-side silicon anisotropic wet etching and aluminum sacrificial layer etching technique. The voltage responsivity of derived 3D thermoelectric structure with 180×180 µm2 pixel size can be as high as 190 V/W in vacuum. This new thermoelectric structure shows its potential to be an excellent pixel structure of infrared sensor array for infrared recognition applications.
Characteristics of Piezoresistive Mass Flow Sensors Fabricated by Porous Silicon Micromachining
Authors: Kim Dong-Kwon , Kang Sung-Gyu , Sim Jun-Hwan , Shin Jang-Kyoo , Choi Pyung , Lee Jong-Hyun
Published: October 2002

Piezoresistive flow sensors with four different types of micro-cantilever structures were fabricated by using (100), n/n+/n three-layer silicon wafer and their characteristics were investigated. Piezoresistors were formed through boron diffusion and its value was about 1 kΩ. Three dimensional micro-cantilevers were fabricated by porous silicon micromachining technique and the cantilevers were curled by annealing at 450°C. Wheatstone bridge was formed with two piezoresistors and two fixed resistors in order to measure the output response of the fabricated sensor. The output voltage was increased with increasing cantilever length while the detectable measurement range was extended with decreasing length of micro-cantilever. The output voltage of the fabricated sensors was increased with the quotient of 3.2 of the flow rate.
New 3.5′′ Magneto-Optical Disk System: 1.3 GB GIGAMO –Technology, Design Concept and Reliability–
Authors: Yoshimura Ken-ichi Itoh , Ogawa Koichi
Published: October 2002

We have developed and commercialized a new-generation 3.5′′ magneto-optical (MO)
disk system, the GIGAMO, which marks the world's first utilization of magnetically induced
super resolution (MSR) to realize 1.3 GB capacity and the high performance of up to 5.9 MB/s
data transfer rate. The system design and the format are optimized, especially for the purpose
of achieving complete downward compatibility with former 3.5′′ MO families from 128 MB to
640 MB media. The improvement of media characteristics and intelligent firmware
development of the drive system enable us to ensure usage at various temperature and repeated
write/read cycles.
Micromachining of Optical Fiber Using Reactive Ion Etching and Its Application
Authors: Kumazaki Hironori , Yamada Yoshihisa , Oshima Takamasa , Inaba Seiki , Hane Kazuhiro
Published: October 2002

Reactive ion etching (RIE) experiments were performed on an optical fiber which was loaded onto an rf cathode and exposed to a low-pressure discharge of CF4 gas. This method enables the fabrication of slender optical fibers with almost uniform diameter in specified regions, but has no significant effect on the core of the fiber which is the propagation path of the signal. An optic variable attenuator was demonstrated using glycerine as an additional cladding on a thinned optical fiber of diameter 22 µm. The glycerine temperature change of 40°C caused an attenuation of 12 dB at 1550 nm. The application of a micromachined single-mode grating fiber (10/125 µm, grating wavelength: 1550 nm) to an optical fiber sensor for detecting the refractive indices of surrounding materials was examined.
Single-Molecule Dynamics of the Eco RI Enzyme using Stretched DNA: its Application to In Situ Sliding Assay and Optical DNA Mapping
Authors: Kabata Hiroyuki , Okada Wataru , Washizu Masao
Published: October 2002

The Eco RI enzyme is a nanomachine responsible for gene integrity in cells, and has a sensor that discriminates its specific binding sequence on DNA (GAATTC) from flanking nonspecific sequences. We applied this sequence sensing ability to microscopic DNA mapping. Visible measurement of positions of the GAATTC sequence was accomplished with fluorescently labeled Eco RI and DNA that was stretched by dielectrophoresis and suspended above a glass surface. Statistics showed that Eco RI molecules were trapped at particular positions on stretched DNA where GAATTC sequences are located. Dwell time at trapped positions agreed with the lifetime of the specific DNA-Eco RI complex previously measured. In a flowing stream, Eco RI molecules moved along stretched DNA and were trapped at putative GAATTC sequences, providing evidence of sliding as a mechanism for relocation of Eco RI on DNA. This single-molecule-based method can be a lab on a chip for mapping genomic DNA and analyzing motility of DNA-binding nanomachines.
New Additional Layer to Realize Initialization-Free Function for Digital Versatile Disk-Random Access Memory Disk
Authors: Miao X. S. , Chong T. C. , Shi L. P. , Tan P. K. , Li F.
Published: October 2002

Digital versatile disk-random access memory (DVD-RAM) with the
Sb2Te3 additional layer demonstrated the initialization-free function. The results
of the reflectivity, X-ray diffraction (XRD) and differential scanning calorimeter
(DSC) confirmed the initialization-free function. No significant decrease of the
modulation amplitude after 1000 overwriting cycles was observed. A reduced
time was required for complete erasure.
Signal Processing for 15/27 GB Read-Only Disk System
Authors: Yokogawa Fumihiko , Miyanabe Shougo , Ogasawara Masakazu , Kuribayashi Hiroki , Tomita Yoshimi , Yamamoto Kaoru
Published: October 2002

In order to realize 15/27 GB read-only disk systems using blue
laser, new signal processing is required.
The technology of large-scale integrated circuits has advanced
considerably. Hence we can use a
complicated circuit with a big gate size without increasing the system
cost significantly when we
fabricate the blue laser disk system. We have realized the 15/27 GB
system using the two-dimensional
equalizer and the limit equalizer. The two-dimensional equalizer was
composed of the cross-talk cancel
system and the asymmetry compensation type tangential adaptive
equalizer. And could improve the
deterioration due to the inter symbol interference and the cross-talk
from the adjacent tracks. The limit
equalizer could improve the deterioration due to the disk noise. Using
these signal-processing systems,
we could reduce the bottom jitter by more than 3% and expand the tilt margin.
A Nonlinearity Compensated Channel Model and Partial Response Maximum Likelihood (PRML) Simulator for the High Density Optical Disc
Authors: Ahn Seong-Keun , Kim Hyung-Nam , Jeong Seong-Yun , Park Kyung-Chan , Kim Jin-Yong
Published: October 2002

A practical model for precise simulation of the high density disc (19.5 GB) channel is suggested and compared with the
linear convolution model. Nonlinear effect compensation is shown to be useful for the practical approach. Partial response
maximum likelihood (PRML) simulation results with the nonlinearity
compensated channel model are presented.
New 8–15 Modulation Code and Reproducing Techniques for High-Density Optical Recording
Authors: Hayami Atsushi , Tonami Junichiro , Mochizuki Masaki , Oki Tsuyoshi , Nakamura Hideki , Hayashiyama Takumi , Suzuki Koji , Miyazaki Ken
Published: October 2002

A new modulation code and new signal reproduction processes for a high-density optical
disk system are proposed. With these new techniques, the capacity of the optical disk
system can be 30% higher than the present digital versatile disk (DVD) system. An
evaluation in terms of the bit error rate by both simulation and hardware experiments is also
shown.
High Bandwidth Electro-optic Scanner for Optical Data Storage
Authors: Zhai Jinhui , Huang Yuhong , Schroeck Steve , Messner W. , Stancil Daniel D. , Schlesinger T. E.
Published: October 2002

Beam deflectors can be used as fine tracking actuators to improve track access time and
data rate in future high performance optical disk drives. In this paper we report on the use of an
electro-optic (EO) scanner for optical data storage. Track following has been accomplished using
this EO actuator with a servo bandwidth of 200 kHz, and single-stage
high-speed track switching/following has been demonstrated in a new
optical head tracking system with reduced offset. A fine tracking
experiment has also been demonstrated using an EO actuator with a
voice coil motor (VCM) actuator to extend the fine tracking range. A
new compensator design method, the PQ method, has been used for this
scanner/VCM compound actuator system. Significant improvements in
track switching/following speed are demonstrated with the scanner/VCM
compound actuator as compared to tracking with the VCM actuator
alone.
Photo-Polymer Objective Lens for Red Blue Lasers
Authors: Murao Noriaki , Koyanagi Hajime , Koike Katsuhiro , Ohtaki Sakashi
Published: October 2002

The authors designed a photo-polymer objective lens which can be
used for both red and blue lasers. The following two conditions were
set to facilitate this lens production process.
1) We chose photo-polymer resin as one of the doublet lens materials.
2) One surface of the photo-polymer lens was designed to be
flat.
We installed this lens in pickup heads and played back some disks. Its
performance was almost as good as that of a noncompatible glass lens.
The Development of a Novel Optical Floppy Disk Drive Using a Phase Change Optical Medium and a Quasi-Near-Field Optical Head
Authors: Kim Young-Joo , Hasegawa Yutaka , Goto Kenya
Published: October 2002

The optical memory system still has some shortcomings such as
slow tracking access speed and high
fabrication cost due to its relatively heavy head weight and complex
optical elements. To overcome these
limitations, a new lensless optical floppy disk drive has been
developed using a phase change optical
floppy disk and an external cavity semiconductor laser with a good
antireflection (AR) coating on the
emitting facet. The main components of this novel system are a
contact-type head of quasi-near-field
optics and a phase change medium prepared on a flexible polyimide
substrate. The AR-coated semiconductor laser oscillates externally
with the disk and its laser
emission output shows sufficient variance to
detect the phase difference on the recording layer. In our primitive
drive, the simple optical head shows
good writing performance and the recorded marks present sub-micrometer
size, which indicate the high
possibility of the development of a new, inexpensive floppy system of
above 500 MB data capacity.
Near-Field Phase Change Optical Recording Using a GaP Hemispherical Lens
Authors: Hirota Kusato , Milster Tom D. , Shimura Kei , Zhang Yan , Jo Joshua S.
Published: October 2002

A GaP solid immersion lens and a modified liquid immersion
lens (MLIL) are studied. The phase change marks exhibit a
diameter of approximately 200 nm when recorded by the MLIL.
Design of a Near-Field Probe for Optical Recording Using a 3-Dimensional Finite Difference Time Domain Method
Authors: Hirota Kusato , Milster Tom D. , Zhang Yan , Erwin J. Kevin
Published: October 2002

Tapered dielectric near-field probes are designed for
optical recording by means of a 3-Dimensional finite difference
time domain (FDTD) method. Probe fabrication is attempted with a
double-exposure holographic technique.
High-Density and High-Data-Transfer-Rate Optical Disk with Blue Laser Diode and Ag–In–Sb–Te Phase-Change Material
Authors: Shinotsuka Michiaki , Onagi Nobuaki , Harigaya Makoto
Published: October 2002

We studied phase-change recording using a 405 nm blue
laser diode, an objective lens of numerical aperture (NA)=0.6 and Ag–In–Sb–Te phase-change material. We report land and groove recording on a conventional disk structure with a 0.6-mm-thick and
120-mm-diameter PC substrate. We confirmed the possibility of achieving a high density, 12 GB capacity and a high data-transfer
rate of 30 Mbps, corresponding to that of a read-only digital
versatile disk (DVD-ROM) under the conditions of 6.5 m/s recording
speed, 0.18 µm/bit linear density (minimum mark length
0.27 µm) and 0.42 µm trackpitch.
Dynamic Aperture of Near-Field Super Resolution Structures
Authors: Tsai Din Ping , Yang Chi Wen , Lin Wei Chih , Ho Fu Han , Huang Hung Ji , Ming Yish Chen Ming Yish Chen , Tzu Feng Tseng Tzu Feng Tseng , Chiu Hsiang Lee Chiu Hsiang Lee , Chwei Jing Yeh Chwei Jing Yeh
Published: October 2002

Direct experimental observation of the near-field aperture formed in the super resolution
near-field structure of glass/SiN(170 nm)/Sb(15 nm)/SiN(20 nm) has been achieved using a
tapping-mode tuning-fork near-field scanning optical microscope. Both propagating and
evanescent field intensities were found at the focused spots of the surface of the super
resolution structure. Images of the near-field intensity gradients at different excited laser
powers (0.45–2.33 µW) demonstrated that the area of the static evanescent intensity could be
stably controlled.
Influence of Channel Depletion on the Carrier Charging Characteristics in Si Nanocrystal Floating Gate Memory
Authors: Ryuji Ohba Ryuji Ohba , Naoharu Sugiyama Naoharu Sugiyama , Junji Koga Junji Koga , Ken Uchida Ken Uchida , Akira Toriumi Akira Toriumi
Published: October 2002

The carrier charging/discharging characteristics in a multidot Si nanocrystal floating gate memory are investigated by measuring the gate current directly. To detect a small gate current, we use a large device-size memory. In the gate current characteristics, double peak structures, with one of the peaks at the threshold voltage and the other at the flat-band voltage, are found. The separation into two peaks is shown to be due to the change of the charging/discharging carrier sources between the source/drain and the substrate in the channel depletion region. These show that the carrier charging/discharging characteristics change critically at each of the threshold voltage and the flat-band voltage. Charging/discharging rate reduction due to the surface potential flexibility and the carrier number shortage in the channel depletion region is proposed to explain the critical changes.