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BACKGROUND Accurate detection and monitoring of disease-related biomarkers is important in understanding pathophysiology. We devised a rapid immunoreaction system that uses submicrometer polymer-coated fluorescent ferrite (FF) beads containing both ferrites (magnetic iron oxide) and fluorescent europium complexes. METHODS FF beads were prepared by encapsulation of hydrophobic europium complexes into the polymer layers of affinity magnetic beads using organic solvent. A sandwich immunoassay using magnetic collection of antibody-coated FF beads to a specific place was performed. Brain natriuretic peptide and prostate-specific antigen were selected as target detection antigens to demonstrate the feasibility of this approach. An immunohistochemical staining using magnetic collection of antibody-coated FF beads onto carcinoma cell samples was also performed. RESULTS The sandwich immunoassays, taking advantage of the magnetic collection of antibody-coated FF beads, detected target antigens within 5 min of sample addition. Without magnetic collection, the sandwich immunoassay using antibody-coated FF beads required long times, similar to conventional immunoassays. Using the magnetic collection of antibody-coated FF beads, immunohistochemical staining enabled discrimination of carcinoma cells within 20 min. CONCLUSIONS This proof of principle system demonstrates that immunoreactions involving the magnetic collection of antibody-coated FF beads allow acceleration of the antigen–antibody reaction. The simple magnetic collection of antibody-coated FF beads to a specific space enables rapid detection of disease-related biomarkers and identification of carcinoma cells.

Electron projection lithography (EPL) is a realistic technology for the 65nm node and below, as a complementary technology of optical lithography especially for contacts and gate layers because of its high resolution and large process margin. Nikon has developed an EPL exposure tool as an electron-beam (EB) stepper and the first generation EB stepper; NSR-EB1A is now almost completed as an R&D tool for the 65nm technology node. Using a ϕ200mm reticle, a 20mm×25mm exposure field is realized. Full-field exposure performance of NSR-EB1A is shown. A 70nm isolated line and 1:1 nested lines are simultaneously resolved, as are 50nm 1:2 nested lines. 60nm contact holes are resolved with a depth of focus over a 10μm range and dosage window over ±6%. Stitching accuracy is about 20nm (3σ) and the single machine overlay is about 30nm (mean + 3σ). These data mean sufficient performance for device manufacturing of the 65nm technology node. The concept of a large subfield is one candidate for resolution and throughput e...

The performance of the electron optical (EO) column of Nikon's EB-stepper mounted on its test stand is reported, mainly focusing on the subject of resolution as preliminary results. Stitching data will be presented in the next paper at MNE2002. Resolution performance data are presented with SEM photos of line/space patterns and contact hole features, printed in both positive and negative resists. EO adjustment techniques were established to obtain the maximum resolution with best trajectory optimisation so that both resolution and distortion can meet their specifications. It is essential to have a metrology capability to measure, distortion as well as resolution. Good resolution results have been achieved over the large deflection (5 mm) field of the EO column using the curvilinear variable axis lens (CVAL) concept, which has been demonstrated by IBM theoretically and experimentally. Current beam blur, depth of focus (DOF) and some characteristic features of the EO conditions are also demonstrated. Image blur at small-deflected positions has also been determined by a direct measurement method. The minimum feature size of 50 nm and a large depth of focus over 5 µm, have been obtained. Overall performance over the whole 5 mm deflected range has not been accomplished yet due to stability limitations of the test stand stage, but good 80-nm line and space resist images have been obtained for the whole deflected range.

In this article, we present experimental results that quantify the magnitude of chromatic aberrations induced by a SiNx continuous membrane mask. We used a continuous membrane mask, which consists of a TaSi scatterer layer on a SiNx membrane layer of 100 nm thickness, for the experiments. The beam edge profiles were measured directly by the knife-edge method, which can measure the image blur with the repeatability of 3 nm (3 sigma). The effect of electron energy loss induced by inelastic scattering is clearly shown in the measured beam edge profiles. The magnitude of chromatic aberrations is quantified from the measured beam edge profiles considering lens aberrations and measurement errors. The results show that lower atomic number Z and lower density materials and thinner membrane are required on the mask membrane for a high resolution lithography.

PREVAIL is the high throughput e-beam projection approach to NGL, which IBM is pursuing in cooperation with Nikon as alliance partner. Key lithographic building blocks of the technology have been demonstrated experimentally with a proof-of-concept (POC) system and results have been reported earlier at MNE 99 and elsewhere. This paper reports on the implementation of the PREVAIL technology in a production-level e-beam stepper. The architecture and writing strategy of the tool together with design features of the various tool subsystems are described.

The IBM/Nikon alliance is developing an EPL stepper alpha tool based on the PREVAIL technology. This article provides a status report on the alliance activity with particular focus on the electron optical subsystem developed at IBM. We have previously described design features of the PREVAIL Alpha system. The state-of-the-art e-beam lithography concepts have since been reduced to practice and turned into functional building blocks of a production level lithography tool. The electron optical subsystem has been designed, built, assembled, and tested at IBM’s Semiconductor Research and Development Center (SRDC) in East Fishkill, NY. After demonstrating subsystem functionality, the column, an interim mechanical system and all associated control electronics hardware and software have been shipped during January 2001 to Nikon’s facility in Kumagaya, Japan, for integration into the Nikon commercial e-beam stepper Alpha tool. Postshipment activity has been directed primarily toward demonstrating subfield stitching, a task which exercises system architecture, calibration, stability, and noise performance.

We describe a direct measurement of the image blur and defocus induced by Coulomb effects (stochastic and global space charge) in electron beam projection lithography. The Nikon 100 kV electron beam projection experimental column was used for the experiments. This column has similar values of electron optical parameters to those of electron beam projection lithography (EPL) systems. The Coulomb effect image blur and defocus were directly measured by a knife-edge method. The experimental data of Coulomb effect image blur and defocus as functions of beam current are shown. The experimental results show excellent agreement with our Monte Carlo simulation results.

Projection reduction exposure with variable axis immersion lenses (PREVAIL) represents the high throughput e-beam projection approach to NGL, which IBM is pursuing in cooperation with Nikon as alliance partner; another e-beam projection approach is SCALPEL pursued by Lucent Technologies. This article discusses the challenges and accomplishments of the PREVAIL project. It will focus on the results obtained with the proof of concept (POC) system. This system was developed to demonstrate key technical building blocks required for high throughput, high resolution e-beam step, and scan projection lithography. The supreme challenge facing all e-beam lithography approaches has been and still is throughput. Since the throughput of e-beam projection systems is severely limited by the available optical field size, the key to success is the ability to overcome this limitation. The PREVAIL technique overcomes field-limiting off-axis aberrations through the use of variable axis lenses, which electronically shift the o...

Dedicate beam line for R&D on contamination of EUV exposure tools (BL18) was constructed at Saga Light Source (SAGA-LS) and its operation has been started. BL18 has an advantage of long time exposure, which gives accurate data compared with high-EUV-intensity and short-time experiments using an undulator beam line at New SUBARU synchrotron facility. Carbon contamination growth under low irradiance EUV radiation with fluorocarbon gas injection was examined using Mo/Si multilayer mirror samples. In the EUV intensity region from 11 W/cm2 to 0.01 W/cm2, degradation rate of reflectivity did not depend on the EUV intensity. The degradation rate was proportional to the EUV intensity in the range of less than 0.01 W/cm2. Carbon contamination due to resist outgas during EUV exposure was also investigated.

Si/Mo multi-layer mirrors are oxidized by a photochemical reaction with water gas and extreme ultraviolet (EUV) light. They do not have enough durability in EUV lithography tools. 14 types of capped mirror samples (SiO 2 , TiO 2 , V 2 O 5 , Cr 2 O 3 , Mn 2 O 3 , Y 2 O 3 , Nb 2 O 5 , RuO 2 , Rh 2 O 3 , PdO, SnO 2 , La 2 O 3 , CeO 2 , WO 3 -capped) have been investigated on the anti-oxidation property under the 150-1600J/mm 2 EUV irradiation at SR facilities. We have irradiated samples under the 1x10 -4 Pa and 9x10 -4 Pa water vapors. TiO 2 , V 2 O 5 , Cr 2 O 3 , Nb 2 O 5 , CeO 2 -capped mirror samples suppress reflectance drops and Si layers oxidation. These metal ions have similar radii. We have measured local structure of the RuO 2 layer with lower durability. The RuO2 layer is amorphous. This Amorphous RuO 2 layer loses the long range order of bonds and the short range order of the first shell. The Ru-O bonds remains with losing coordination number. To accelerate durability tests for a high volume machine, we have constructed a new dedicated beam line at the SAGA Light Source.

It is very important to mitigate oxidation of multilayer mirrors (MLMs) and carbon deposition onto MLMs to extend the lifetime of EUV exposure tool. We focused on carbon deposition on Si-capped multilayer mirror. We made experiments of EUV irradiation to the multilayer mirrors using an EUV irradiation apparatus connected to a beam line (SBL -2) of synchrotron radiation facility Super-ALIS in the NTT Atsugi research and development center. Thickness of deposited carbon was obtained by using XPS. We investigated carbon deposition rates at various partial pressures of various organic species. Phenomenological analysis was applied to the obtained carbon deposition rate. Carbon deposition rate was proportional to the pressure at the proportional EUV intensity. Applying this normalization of the deposition rate and the EUV intensity, carbon deposition rate seems to behave according to each universal function for each hydrocarbon species.

Electron Projection Lithography (EPL) is considered one of promising technologies below 45nm node, especially for contact/via holes and gate layers. EPL has some nice features such as very high resolution to be applied for two device nodes, large process margin associated with large depth of focus and an expected lower CoO. Nikon has been developing an EPL tool, so-called EB Stepper. NSR-EB1A is the first EB Stepper that was designed as R&D tool for 65nm technology node and that was already delivered for Selete (Semiconductor Leading Edge Technologies, Inc.) at Tsukuba in Japan. Nikon has developed two NSR-EB1A tools so far, one system for Selete as a 300mm wafer system and the other for Nikon's development and evaluation as a 200mm wafer system. Both tools have already started to show full performance data and good stability characteristics. The latest EB1A tool performance shows very good results in such data as the resolution of 50nm 2:1 L/S and 60nm 1:1 dense contact holes patterns, stitching accuracy of around 18nm, and overlay accuracy of around 20nm(X+3sigma).

The timely development of a Next-Generation Lithography depends upon its progress in many technology-dependent areas. Common to all high-throughput systems is the requirement of strict mask distortion control. Thus, in support of the Nikon electron-beam projection lithography tool program, three-dimensional finite element (FE) models have been developed to simulate the transient thermal and structural response of a 200-mm prototype stencil mask during electron beam exposure. Due to the relative size of pattern features, equivalent modeling techniques were employed for computational expedience. Equivalent thermal properties (conductivity and emissivity) have been calculated for perforated membranes as a function of pattern void fraction. Resulting temperature distributions were used as input for the FE structural models to characterize and quantify the local displacement fields. The structural models also utilized equivalent material properties (elastic modulus, shear modulus and Poisson's ratio). Support conditions corresponded to electrostatic chucking with four symmetrically located pad regions. The FE simulations predicted that under typical exposure conditions, the localized thermal distortions within the individual subfields are all less than 1.0 nm, which is well below the allotted error budget.

As Next Generation Lithography (NGL) systems, several systems are proposed. EPL (Electron Beam Projection Lithography) system, which is one of NGL systems using electron beam (EB), is expected to be a most promising candidate, which has a high throughput (>20 wph of a 300 mm wafer) and a high resolution (

Silicon stencil reticle has been developing for the EB stepper, which is the electron beam projection lithography system for 70nm node generation and beyond. The reticle distortion is affected by stress such as silicon membrane stress and resist stress on a reticle in their fabrication. To analyze pattern distortion using finite element method (FEM), the image placement (IP) and the critical dimension (CD) errors of the stencil reticle were measured at every step of reticle fabrication processes. It was found that the resist stress is the key factor of IP error in the membrane process. In the wafer process, the IP errors are mainly related to silicon membrane stress. IP and CD errors of 200mm stencil reticle in both processes are discussed using FEM. The calculation results show CD errors are caused by the stress of silicon membrane. Moreover, it is discussed that CD error depends on pattern shape and density even on the stress-controlled reticle blanks.

Nikon, in collaboration with IBM, has been developing EB stepper, which is the electron beam projection lithography (EPL) system for 70 nm node generation and below. As the standard reticle for EB stepper, the scattering silicon stencil type is used to obtain highest performance. The EB reticle has thin silicon membranes of thickness 2 micrometers and membrane size 1.13 mm square with stencil opening patterns, which are supported by a grid-grillage structure. The development of the EB reticle is one of key issues in the EB stepper development. We had accomplished 76nm reticle development using silicon-on-insulator wafer with a stress- controlled membrane. Now we are in the 200 mm reticle development phase. We have curried out experiments in cleaning, inspection and repair for the EB reticle, which are very important issues for the EB reticle fabrication. We showed possibilities of Ar aerosol cleaning, a reticle repair using Focused Ion Beam, pattern defect inspection with DUV microscope and so on.

A direct means of measuring an image blur of electron beam projection lithography (EPL) tools is described. An aerial image sensor used for the image blur measurement was fabricated and evaluated. The signal to noise ratio (SNR) was very high and the signal contrast was 97%. The measured image blur, defined as the distance between 12% and 88% of the beam edge profile, under the optimum condition was 13 nm and the measurement repeatability was 3 nm (e sigma). The measurement error due to the sensor was extremely small, and a quantitative measurement of the image blur can be realized using this technique. The application of this technique to a system calibration is demonstrated. Focus and astigmatism were measured and the optimum settings of focus coils and stigmators were determined with an excellent repeatability. The potential for this technique to provide an automated self-calibration system on the EPL tools is clearly shown.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The latest development status of EB Stepper is reported. The experimental data include the latest resist image data exposed by 100keV electron beam, mask error factors and dosage margins at several backscattered electron levels, transmission data of continuous membrane reticles, and recommended structures for alignment marks, etc. The basic studies related to system design are also explained, those are the strategy for the management of reticle deformation and the stitching accuracy in overlaid layers, etc. Through these data, the resolution capability down to 50nm technology node is clearly shown and alignment/stitching capability is also described. The requirement to a continuous membrane reticle is indicated from experimental data.

The imaging concept of electron projection lithography (EPL) with silicon stencil reticle is explained. A silicon membrane thickness of 1 - 4 micrometer is suitable for the reticle. A scattering contrast of greater than 99% is expected. Nikon EB stepper's dynamic writing strategy of discrete exposure on a sub-field by sub-field basis with deflection control of the electron beam is explained. The basic system configuration of EB stepper is introduced. Examples of error budget for CD variation and Overlay/Stitching are shown. Nikon's policy for countermeasures for critical issues such as proximity effect correction, sub-field/complementary stitching and wafer heating influence are explained. For extensibility down to 70 nm and below, both exposure tool and reticle should be improved.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The stencil reticle is one of masks for EPL (Electron beam Projection Lithography). The ability to repair pattern defects in such masks is an essential requirement for their use. For clear defects, repair issues include deposition on the stencil pattern, electron scattering properties of the deposition material, stability of the repair against 100 kV electron beam (EB) bombardment and etching and pattern profile accuracy. For opaque defects, ion milling of the stencil material to high accuracy is required. In this paper, we discuss the repair deposition of clear defects up to 0.15 micrometer using a carbon-compound precursor and the critical dimension (CD) controllability of the exposed resist pattern with various thickness of repair depositions using Nikon's EB experimental projection column (100 kV). In addition, using a Monte Carlo simulation of the electron scattering in the silicon membrane and the repair deposition, the beam contrast is estimated for EPL at contrast aperture (CAP) size. The resist CD can be controlled using more than 2 micrometer-thick Diamond like Carbon (DLC) deposited on the stencil reticle and shaped by focused ion beam (FIB). Profiles, pattern sizes and the electron scattering properties of DLC repairs are stable against 100 kV EB irradiation (about 2 C/cm2 dosage; corresponding to half-year dosage). These results show the possibility of DLC as the repair material for clear defects. The possibility of repairing opaque defect, which involves FIB milling of sizes from 0.2 to 0.4 micrometer, is also demonstrated.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

An electron projection lithography (EPL) system which projects reticle patterns onto a wafer will be applied to sub 100 nm lithography. Requirements for line width accuracy are very strict as feature sizes are less than 100 nm. For electron beam lithography, proximity effect corrections have always been an important issue for accurate feature width control. In this paper characteristics of several correction methods are examined, and appropriate correction methods for 100 kV EPL are introduced. Employing the shape correction method burdens the reticle pattern preparation system much more than other methods. Therefore a calculation method suitable for 100 kV EPL where the backscatter radius is very wide ((beta) b approximately equals 30 micrometer) and the forward scatter radius is narrow ((beta) f approximately equals 7 nm) has been developed. The calculation of deposition energy by the backscattered electron beam is carried out with a coarse grid but wide range. The calculation of the combined effect of the electron scattering blurs from the features is carried out only within a narrow range. The correction calculation is carried out using both of these results. Using this method, accurate and fast calculations can be achieved. Employing the GHOST correction method increases total exposure cost. The practical GHOST correction methods may also be improved. An additional correction method named shape correction with GHOST is also shown.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Nikon is developing an Electron Beam (EB) stepper as one of the next-generation lithography systems for feature sizes of less than 100 nm. As a reticle for the EB stepper using a high power EB (acceleration voltage: 100 kV, current on reticle: 100 (mu) A), a scattering stencil reticle with a grid-grillage structure has been investigated, EB projection experimental column which operates a high power EB was constructed. Some experimental data of scattered electron characteristics using the EB projection experimental column are given as follows: (1) Scattering contrast of 99.9% can be obtained using 100 kV electron beam (membrane thickness; 2 micrometer, aperture half angle onto reticle; 2 mrad). (2) Changes of resist pattern width of 1:1 and 1:2 lines and spaces are around 40% and around 20% respectively due to the proximity effects by backscattered electrons form the silicon substrate. (3) Contrast of EB mark detection for the system calibration, the reticle alignment, and the wafer registration is obtained. Comparing with the values that be obtained by theoretical calculation, some of experimental data gave good agreement.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

To estimate the optics lifetime of an extreme ultraviolet lithography (EUVL) system with a contaminated mirror surface, it is indispensable to carry out an acceleration test using high-flux EUV irradiation. In this study, Mo/Si multilayer mirrors were irradiated in various vacuum environments using a contamination evaluation system with an undulator light source, and changes in their reflectivity were evaluated. The dependence of the decrease in reflectivity per unit dose on the EUV irradiance was observed in high-flux irradiation experiments in vacuum with water vapor or n-decane gas introduction at pressures lower than about 10-5 Pa. The irradiance dependence disappeared when the pressures were increased for both water vapor and decane gas. A reflectivity distribution with a doughnut shape, namely, high at the irradiation center, low in the surrounding area, and high in the non-irradiated area, was observed in the irradiation experiments during the simultaneous introduction of water vapor and decane gas. These results can be generally explained by the mechanism of the supply-controlled limit.

Biosensing platforms based on functionalized superparamagnetic beads acting as “magnetic-labels” show tremendous potential for rapid and highly-sensitive point of care medical diagnosis. Recently, for greater quantification, there are increasing demands for the use of magnetic labels with diameters of 8–150 nm, which are comparable in size to actual biomolecules. However, detection of small numbers of sub-150 nm sized magnetic beads by magnetoresistive device-based platforms is extremely challenging due to the intrinsic noise of these electronic devices. Here, we describe an easy and economical detection method of low areal densities of 8-nm-diameter superparamagnetic “target beads” immobilized over millimeter-sized substrates by optically monitoring the magnetically induced “capture” of easily visible, micrometer sized superparamagnetic “columnar beads” by the targets in less than a few tens of seconds.

The environmental SEM (E-SEM) can be used unfixed biological samples under a low vacuum and wet condition. In this study, the fractured dentin of unfixed human teeth was treated with a 30% hydrogen peroxide solution (H2O2) for the examination of tooth-bleaching prior to the E-SEM and a conventional SEM. The peritubular matrix (PM) always showed a few cracks along the long axis of a dentinal tubule, and the ends of fine fibrils rose to the smoothly changed surface of the intertubular matrix (IM). The E-SEM with non-fixation and the conventional SEM following fixation indicated that the hydrogen peroxide solution easily permeated the PM and dissolved the non-fibrillar substance including the cracks of the PM by the constriction. In the IM, the solution may partially dissolve the organic parts within mineralized fibrils as well as non-fibrillar substance between the fibrils, although these remnants might precipitate again there.

The Coulomb effects have been common problems in electron-beam lithography. In our previous article, we studied the influence of the Coulomb effects on electron projection lithography (EPL) process. In this paper, we analyze the Coulomb effects by direct blur measurements and by simulations. We found that there existed a beam blur around 32 nm at a low beam current (approximately 0μA). We found a relationship between the beam blur and the beam current that was 5.4nm∕μA, and this number agreed with our simulation work as well as with our experiment with resist resolution. We learned that at low current the blur was so small that a blur distribution could be practically ignored. An important finding we had, is that the beam blur did not only depend on the beam current but also on the pattern arrangement. We found the possibility of the existence of the local Coulomb effects and estimated its range to be around 100–120μm on our system. These phenomena should be taken into considerations when making proximity...

Electron projection lithography (EPL) is one of the promising technologies below the 65 nm node, especially for contact hole and gate layers. Nikon is developing an EPL exposure tool as an electron beam (EB) stepper and the first generation EB stepper is now being manufactured. The voltage of 100 kV is adopted for electron beam acceleration. The subfield size is 0.25 mm×0.25 mm on the wafer and the deflection width of the electron beam is 5 mm on the wafer. The magnification of the projection optics is 1/4. A 5 mm×25 mm area from the φ200 mm reticle can be exposed by the combination of beam deflection and stage scanning motion (dynamic exposure). This area is called “a mechanical stripe.” After one mechanical stripe exposure, the reticle and wafer stages turn around and the next exposure of the adjacent mechanical stripe starts as a scan and stitch stage motion. Finally, a 20 mm×25 mm exposure field from the φ200 mm reticle is exposed. We report the first dynamic exposure in the history of EPL although only a φ100 mm reticle was used. A 5 mm×10 mm area was used as the mechanical stripe and 10 mm×10 mm exposure fields were exposed. 100 nm nested lines were resolved in the entire exposure field and stitching accuracies of 17–18 nm (3σ) are obtained. There remain systematic errors, and stitching accuracy less than 15 nm will be achieved after fine adjustment of the subfield positions. We feel the reality of EPL is now sufficiently proven.

Repair of stencil reticles for electron beam projection lithography system is one of the critical issues on reticle manufacturing.Focused ion beamdeposition is studied as the method for repairing the clear defects of stencil reticle. The film deposition of diamondlike carbon (DLC) across the stencil pattern, on the sidewall of the stencil, and on the pre-etched slot pattern is demonstrated. The deposited DLC films have good properties as the repair material.Deposited patterns across the stencil pattern are imaged on the resist with the Nikon 100 kV experimental projection column. When the thickness of the deposited DLC film is more than 0.5 μm and the contrast aperture size of the projection column is 1.5 mrad, the thickness of the deposited pattern does not affect the critical dimension of the resist pattern imaged the repaired patterns. The profiles, the pattern size, and the electron scatteringproperties of DLC films are stable for 100 kV electron beam continuous irradiation (2 C/cm2 dosage; corresponding to half-year dosage on electron beam stepper). Moreover, the repaired pattern is not damaged by the wet megasonic cleaning.

We have fabricated Si stencil reticles that are employed by a new type of e-beam projection lithography system (EB stepper). We applied a stress reduction technique to the Si membrane to improve the pattern placement accuracy. The residual stress of Si membranes which were fabricated by anisotropic etching of B-doped Si wafers in KOH aqueous solution was reduced by annealing at 1150 °C. We carried out pattern-displacement measurements for a Si stencil reticle made of a Si membrane where the residual stress was reduced to 10 MPa, and we observed that the pattern displacement error was reduced to less than 20 nm. Furthermore, the pattern displacement in the stencil reticle had a high correlation with the displacement determined from a simulation based on a finite element model. However in the same reticle, we discovered additional, comparatively small displacements in random directions, which was not expected in a membrane that had a homogeneous tensile stress. As a cause of the pattern displacement in rand...

The environmental scanning electron microscope (ESEM) have recently been developed to permit the observation on wet specimens under environmental gas conditions by improving the differential vacuum system. ESEM has been successfully applied to some fields of material science. However, its application to biological samples is still limited. Hence, we tried to examine the availability of ESEM for the fine structural observation on mammalian soft tissues under saturated water pressure without drying.Adult male DDN mice were used for materials. Fresh tissues without fixation were excised under barbital anesthesia. The tubular viscera were opened and washed with saline after excision and mounted on the ice-chilled specimen holder and examined under ESEM. Internal structures of the parenchymal organs were examined on the exposed surfaces by cutting with razor blades after perfusion fixation with ½ Karnovsky fixative. Some specimens were postfixed with 1 % OsO4. After fixation, the specimens were rinsed with saline and examined under wet condition.

A new linewidth measurement system is developed using the environmental scanning electron microscope (ESEM) technology. The system shows good performance for a deep submicron device metrology tool. Here we will describe outlines of the system and some results of linewidth measurement and hole observation.

The spatial coherence and the beam divergence at 248 nm of a KrF excimer laser were obtained experimentally. These results are in good agreement with the theoretical calculations based on a simple pulse-laser model and the van Cittert-Zernike theorem. The relation between the spatial coherence and the beam divergence was obtained theoretically and supported by experimental results. This expression is given as a function of the wavelength of the laser but includes no parameters related to the laser structure. It is shown that these theoretical results are applicable to various kinds of pulse laser.

A high intensity pulse light source from a high density plasma in a sliding spark with an electron beam is useful in the vacuum ultraviolet (vuv) and soft X-ray regions. Its spectra in the 100–500 A region are shown and line profiles are compared with numerical results calculated from the local thermodynamic equilibrium (L.T.E.) plasma model.

An illumination system suitable for an excimer laser stepper has been investigated. Unnecessary interference pattern(speckel) is reduced effectively by scanning the laser beam. We report spatial coherence of the lasers with different spectral line width, illumination system of the stepper, appearance of the interference pattern,its spacing and contrust and their relation to the illumination system and to the coherence of the laser. Then we report reduction of this pattern together with a simple method to measure its contrast.