Real-time Thickness Measurement Research Articles

Real-Time Air Gap and Thickness Measurement of Continuous Caster Mold Flux by Extrinsic Fabry–Perot Interferometer

Real-Time Air Gap and Thickness Measurement of Continuous Caster Mold Flux by Extrinsic Fabry–Perot Interferometer

The comparison of multi-stepping algorithms for real-time thickness measurement of transparent thin films using polarization settings

This paper presents the comparison of three-, four- and five-step techniques for measuring transparent thin-film thickness of and deposited on BK-7 substrates. The Sagnac interferometer was modified with phase shifting approach for the determination of thin-film thickness. The input light beam was split into reference and testing beams. Before the output light reaching the balanced photodetectors, the real-time signal detection was performed to obtain the output intensities of both beams using three-, four-, and five-polarization settings of an analyzer. The thicknesses could then be efficiently translated from the measured intensities. Thicknesses from three-, four- and five-stepping algorithms were compared with ones from the conventional FE-SEM measurement, and it was discovered that the former performed better with less errors. The findings show that the phase-shifting technique using three-polarization settings is more suitable for the thickness measurement of the transparent thin film.

Optimizing catheter ablation of atrial fibrillation by a novel wide-band dielectric imaging system: first experience on real-time wall thickness measurement

Abstract Funding Acknowledgements Type of funding sources: None. Background Conventional mapping systems do not provide wall-thickness data, which is, however, known to be a determinant of radiofrequency ablation lesion transmurality. KODEX-EPD is a novel open-platform system, which uses dielectric tissue properties to provide real-time, high-resolution cardiac images, tissue characteristics and wall-thickness measurement to guide ablation procedures. Aim The aim of this case series was to report on our first experiences with KODEX-EPD regarding estimation of myocardial wall-thickness during catheter ablation of atrial fibrillation (AF). Methods We retrospectively analyzed consecutive patients undergoing radiofrequency AF-ablation in combination with KODEX-EPD. A high-resolution image from the left atrium (LA) and the pulmonary veins (PV) was obtained prior to ablation using a spiral mapping catheter in conjunction with KODEX-EPD. Wall-viewer points were collected within the LA, the PVs and the left atrial appendage (LAA) using a standard radiofrequency non-contact force ablation catheter and analyzed for wall-thickness applying the latest KODEX-EPD software version (1.5.0, not yet commercially released). Wall-viewer points were divided into a total of 10 segments (PV ostia, anterior wall, posterior wall, LA roof, LA floor, LAA and PV carina, details see Figure 1) in order to characterize wall-thickness in respective areas. Results A total of 570 wall-viewer points in 5 patients were analyzed. Most of the wall-viewer points were collected at the PV ostia as well as along the posterior and anterior wall (449/570, 79%). Actual myocardial atrial thickness ranged from 1.6 to 3.9 mm. Thickest myocardial LA-tissue was measured at the anterior wall (median 3.1 mm) and thinnest at the LA-roof (median 2.2 mm). Figure 2 gives a detailed distribution of wall-thickness measurements at different sites in the LA and PVs. Conclusion Atrial wall thickness can be estimated in patients during AF ablation procedures using dielectric tissue properties. Further evaluation and validation of the method are needed to study its reliability and utility for clinical practice.

Real-Time Thickness Measurement of Marine Oil Spill by Fiber-Optic Surface Plasmon Resonance Sensors

Rapid detection of marine oil spills is becoming increasingly critical in the face of frequent marine oil spills. Oil slick thickness measurement is critical in the hazard assessment of such oil leaks. As surface plasmon resonance (SPR) sensors are sensitive to slight changes in refractive index, they can monitor offshore oil spills arising from significant differences in the refractive index between oil and water. This study presents a gold-film fiber-optic surface plasmon resonance (FOSPR) sensor prepared by polydopamine accelerated wet chemical plating for rapid and real-time measurement of oil slick thickness. We examined oil thickness detection at two interfaces, namely, water-oil and air-oil. Detection sensitivity of −1.373%/mm is obtained at the water-oil interface in the thickness range of 0–5 mm; detection sensitivity of −2.742%/mm is obtained at the air-oil interface in the thickness range of 0–10 mm. Temperature and salinity present negligible effects on the oil slick thickness measurement. The fabricated FOSPR sensor has the ability to detect the presence of oil as well as quantify the oil thickness. It has favorable repeatability and reusability, demonstrating the significant potential for use in the estimation of marine oil slick thickness.

Thickness Measurement Based on Eddy Current Sensor With Coaxial Double Coil for Chemical Mechanical Polishing

Real-time and accurate thickness measurements of copper films on 300-mm silicon wafers are utilized to improve global planarization, control polishing pressure, and avoid dishing and erosion caused by under-polishing and over-polishing during chemical mechanical polishing (CMP) of metals. Nevertheless, the requirements of nanometer-scale measurement sensitivity, wide measurement range from tens of nanometers to 2 μm, and high edge measurement performance make eddy-current thickness measurement extremely challenging. Therefore, we proposed a concise and effective theoretical model to analyze the measurement range and sensitivity in both the amplitude- and phase-based methods. The advantages and disadvantages of the two methods are compared and discussed systematically through simulations and experiments. The effects of the lift-off distance and frequency of excitation signal on measurement sensitivity, range, and edge measurement performance are also examined. The results show that the proposed theory can be used to improve measurement range and sensitivity. And the double-sensor system demonstrated better edge measurement performance than a single coil. Finally, a double-coil eddy current thickness measurement system designed with an average sensitivity of 1.9 mV/nm, a measurement range of 60 nm to 2 μm, and an edge attenuation position of 141.5 mm at a lift-off distance of 3.5 mm can be utilized in the amplitude-based method for advanced Cu-CMP.

Real-Time Double-Layer Thin Film Thickness Measurements Using Modified Sagnac Interferometer with Polarization Phase Shifting Approach

This paper describes a modified Sagnac interferometer with a self-referenced polarization and phase-shifting technique for real-time thickness measurement of single- and double-layer transparent thin films. The proposed interferometric setup generated outstanding rotating linearly polarized light with a degree of polarization (DOP) of 99.40%. A beam splitter placed at the interferometer output separated the beam into two identical linearly polarized beams. One of the beams served as a reference, while the other served as a sensing arm. The output linear polarizer set at 45° relative to a reference plane was positioned anterior to the photodetectors to get rotating light intensities for phase shift measurement; hence, the intensities at various polarizations of 0°, 45°, and 90° were automatically acquired without any polarizing device adjustments. These intensities were then transformed into a phase retardation introduced by a sample, and the resulting phase shift was eventually converted into film thickness. The samples were properly prepared, with pure BK7 substrate being deposited by WO3-, Ta2O5-, and WO3/Ta2O5 films of known thicknesses. The thickness measurement obtained from the proposed system yielded reading errors of 1.3%, 0.2%, and 1.3/2.5% for WO3-, Ta2O5-, and WO3/Ta2O5 films, respectively. The mathematical theory was effectively demonstrated and empirically confirmed. The experimental results show that the proposed setup has a lot of potential for real-time, non-destructive thickness assessment of transparent thin films without the need to modify polarizing device orientations.

Real-time measurement of stave thickness in a blast furnace using sacrificial ultrasonic waveguide

ABSTRACT A stave cooling system is a key element in the blast furnace which protects the outer shell from heat by providing uniform cooling. Real-time condition assessment of staves is essential to understand the wear mechanism of staves. Inspection rod/waveguide of known length which is made of copper was inserted through the steel shell till the inner end of the stave where the waveguide is susceptible to reduce in length as stave erodes with time. FEM analysis was done to find the ultrasonic parameters and lab-scale trials were taken on artificial waveguides with different end conditions. Based on the results, an ultrasonic-based real-time thickness measurement system was developed to continuously measure the length of the inspection rod/waveguide which eventually represents the stave thickness. System was installed in the plant, the data was captured and shown for 60 days from the date of the installation with an accuracy of more than 98%.

B-IN02-02 DIELECTRIC-BASED TISSUE THICKNESS MEASURED WITH A RADIOFREQUENCY ABLATION CATHETER: INITIAL CLINICAL RESULTS

Current algorithms that indicate adequacy of radiofrequency (RF) lesion formation incorporate parameters such as contact force, power, and duration, but omit tissue thickness. A new dielectric-based method for measuring tissue thickness (DTT, Wall Viewer™) at the catheter-tissue interface has recently been developed (pre-market). DTT performance in clinically relevant atrial anatomy, such as the cavotricuspid isthmus (CTI), is unknown. To evaluate the correlation between DTT and tissue thickness measured with intracardiac echocardiography (ICE) in subjects undergoing CTI ablation. Eight subjects at two centers underwent a CTI ablation (NCT03858361 and NCT04438395). Right atrial maps were created with an electroanatomic mapping system (KODEX-EPD). The DTT algorithm is based on a pre-trained algorithm model that incorporates real-time catheter position and local dielectric tissue interrogation by catheter electrodes. Prior to ablation, DTT measurements were taken with an ablation catheter (ThermoCool® SF) along the CTI by blinded operators and compared with tissue thickness determined on stored CTI ICE images after the procedure. Bi-directional CTI block was confirmed with differential pacing. Average RA mapping time was 23 ± 5 min. Acute bi-directional block was confirmed in all subjects. CTI thickness measured with ICE (range 1.3 - 5.0 mm) was compared to DTT tissue thickness at 43 points. There was a significant linear correlation between DTT and ICE tissue thicknesses (p < 0.001, slope: 0.73 and r: 0.57). In total, 86.0% (37/43) of DTT values fell within 1.5 mm of ICE measurements with the largest deviation of 2.1 mm. Clinically relevant atrial tissue thickness was accurately measured by a dielectric-based method with a commercially available RF ablation catheter. Real-time tissue thickness measurement may better inform RF dosing to ensure lesion transmurality while limiting collateral structure damage.

B-PO01-072 DIELECTRIC-BASED TISSUE THICKNESS MEASURED WITH A RADIOFREQUENCY ABLATION CATHETER: INITIAL CLINICAL RESULTS

Current algorithms that indicate adequacy of radiofrequency (RF) lesion formation incorporate parameters such as contact force, power, and duration, but omit tissue thickness. A new dielectric-based method for measuring tissue thickness (DTT, Wall Viewer™) at the catheter-tissue interface has recently been developed (pre-market). DTT performance in clinically relevant atrial anatomy, such as the cavotricuspid isthmus (CTI), is unknown. To evaluate the correlation between DTT and tissue thickness measured with intracardiac echocardiography (ICE) in subjects undergoing CTI ablation. Eight subjects at two centers underwent a CTI ablation (NCT03858361 and NCT04438395). Right atrial maps were created with an electroanatomic mapping system (KODEX-EPD). The DTT algorithm is based on a pre-trained algorithm model that incorporates real-time catheter position and local dielectric tissue interrogation by catheter electrodes. Prior to ablation, DTT measurements were taken with an ablation catheter (ThermoCool® SF) along the CTI by blinded operators and compared with tissue thickness determined on stored CTI ICE images after the procedure. Bi-directional CTI block was confirmed with differential pacing. Average RA mapping time was 23 ± 5 min. Acute bi-directional block was confirmed in all subjects. CTI thickness measured with ICE (range 1.3 - 5.0 mm) was compared to DTT tissue thickness at 43 points. There was a significant linear correlation between DTT and ICE tissue thicknesses (p < 0.001, slope: 0.73 and r: 0.57). In total, 86.0% (37/43) of DTT values fell within 1.5 mm of ICE measurements with the largest deviation of 2.1 mm. Clinically relevant atrial tissue thickness was accurately measured by a dielectric-based method with a commercially available RF ablation catheter. Real-time tissue thickness measurement may better inform RF dosing to ensure lesion transmurality while limiting collateral structure damage.

Real-Time Thickness Measurement Using Resonant Eddy-Current Sensor

In this work, we propose a real-time noncontact thickness measurement system for conductive materials based on an inductor–capacitor ( LC ) resonant eddy-current sensor. For the aluminum, copper, stainless steel 304, and carbon steel samples of various thicknesses, the in-phase and quadrature components of the sensor output taken during liftoff scans are found to be a series of quadratic-like curves on the phase versus logarithmic amplitude diagram. These curves can be used to generate the standard phase–amplitude relations for thickness conversion. The phase–amplitude relations of the thickness between the values of standard samples are calculated by cubic spline interpolation. With the standard database of phase–amplitude relations, the noncontact thickness measurement was implemented in real time for the copper foil sample with an error of ±3% when the liftoff distance is less than 5 mm. The liftoff tolerance is as large as 100% of the probe diameter, indicating that the proposed method is useful for online quality inspection of conductor films on flexible substrates.

Uniform-thickness electrospun nanofiber mat production system based on real-time thickness measurement

Electrospinning is a simple versatile process used to produce nanofibers and collect them as a nanofiber mat. However, due to bending instability, electrospinning often produces a nanofiber mat with non-uniform mat thickness. In this study, we developed a uniform-thickness electrospun nanofiber mat (UTEN) production system with a movable collector based on real-time thickness measurement and thickness feedback control. This system is compatible with a collector with void regions such as a mesh-type collector, two-parallel-metal-plate collector, and ring-type collector, which facilitates the measurement of light transmittance across the produced nanofiber mat during electrospinning. A real-time measurement system was developed to measure light transmittance and convert it to the thickness of the nanofiber mat in real time using the Beer–Lambert law. Thickness feedback control was achieved by repeating the following sequences: (1) finding an optimal position of the movable collector based on the measured thickness of the nanofiber mat, (2) shifting the collector to an optimal position, and (3) performing electrospinning for a given time step. We found that the suggested thickness feedback control algorithm could significantly decrease the non-uniformity of the nanofiber mat by reducing the standard deviation by more than 8 and 3 times for the numerical simulation and experiments, respectively, when compared with the conventional electrospinning. As a pioneering research, this study will contribute to the development of an electrospinning system to produce robust and reliable nanofiber mats in many research and industrial fields such as biomedicine, environment, and energy.

Calibration-free real-time organic film thickness monitoring technique by reflected X-Ray fluorescence and compton scattering measurement

Most thickness measurement techniques using X-ray radiation are unsuitable in field processes involving fast-moving organic films. Herein, we propose a Compton scattering X-ray radiation method, which probes the light elements in organic materials, and a new simple, non-destructive, and non-contact calibration-free real-time film thickness measurement technique by setting up a bench-top X-ray thickness measurement system simulating a field process dealing with thin flexible organic films. The use of X-ray fluorescence and Compton scattering X-ray radiation reflectance signals from films in close contact with a roller produced accurate thickness measurements. In a high-thickness range, the contribution of X-ray fluorescence is negligible, whereas that of Compton scattering is negligible in a low-thickness range. X-ray fluorescence and Compton scattering show good correlations with the organic film thickness (R2 = 0.997 and 0.999 for X-ray fluorescence and Compton scattering, respectively, in the thickness range 0–0.5 mm). Although the sensitivity of X-ray fluorescence is approximately 4.6 times higher than that of Compton scattering, Compton scattering signals are useful for thick films (e.g., thicker than ca. 1–5 mm under our present experiment conditions). Thus, successful calibration-free thickness monitoring is possible for fast-moving films, as demonstrated in our experiments.

Co-axial spectroscopic snap-shot ellipsometry for real-time thickness measurements with a small spot size.

Spectroscopic snap-shot ellipsometry of co-axial structure is proposed to solve the large spot size and long measurement time issues of the conventional ellipsometer. By modulating the spectroscopic ellipsometry signal into high-frequency at the spectral domain and measuring the spectrum at the point of the back focal plane, the ellipsometry parameters(Δ, ψ) were measured in real-time with small spot size. Detailed analysis, calibration, and optimization process for the proposed methods are presented. The accuracy and precision of the proposed method were confirmed by comparing the thickness measurement result of SiO2/Si thin-film samples with a commercial ellipsometer.

박막의 실시간 두께측정을 위한 XRF 장치의 제작 및 Al/metal과 Au/metal계의 특성

박막의 실시간 두께측정을 위한 XRF 장치의 제작 및 Al/metal과 Au/metal계의 특성

Industrial X-ray Fluorescence Analyzer for Real-Time Thickness Measurements of Aluminium Coatings on Rolled Steel

Aluminium coatings that are formed by physical vapour deposition (PVD) on rolled steel products are more resistant to atmospheric and seawater corrosion than zinc coatings. We developed a coating thickness analyzer (CTA) with an X-ray fluorescence (XRF) measuring head, that is integrated into the PVD pilot line. In this study, to conduct measurements of elements with atomic numbers less than 20 while avoiding the problem of registration of light elements, the measuring head was integrated into a process vacuum chamber to maintain a vacuum during the measurements. To validate the proposed tool, cold-rolled steel strips of different grades are used as substrates, and aluminium was deposited on the surface via PVD in thicknesses ranging from 1 to 20 g/m2. The thin-film thickness measurements during a pre-acceptance test were found to have a relative accuracy of less than 5% and a relative precision of less than 1% – 2%. The proposed CTA can be readily integrated in the factory’s automatic process control system and the real-time measurements in operating and calibration modes, and the status of all spectrometric equipment (X-ray tube, detector etc.) can be transmitted to the upper-level computer. Thus, the process engineer can properly control the deposition process.

Interferometric snapshot spectro-ellipsometry.

We propose a snapshot spectroscopic ellipsometry and its applications for real-time thin-film thickness measurement. The proposed system employs an interferometric polarization-modulation module that can measure the spectroscopic ellipsometric phase for thin-film deposited on a substrate with a measurement speed of around 20 msec. It requires neither moving parts nor time dependent modulation devices. The accuracy of the proposed interferometric snapshot spectro-ellipsometer is analyzed through comparison with commercial equipment results.

Advanced GPU-Based Terahertz Approach for In-Line Multilayer Thickness Measurements

In this contribution, an advanced numerical regression approach based on graphics processing unit is introduced. The approach has been applied for real-time terahertz thickness measurements of individual layers within multilayered structures for a variety of industrial applications, including automotive paints, and ceramic coatings. In order to increase the sensitivity and the accuracy of the thickness measurements, a self-calibration method is presented, which can be applied for simultaneous material parameters extraction of all layers from the sample at its final state, taking into consideration all effects that may occur during the coating process.

Real-time dielectric-film thickness measurement system for plasma processing chamber wall monitoring

An in-situ real-time processing chamber wall monitoring system was developed. In order to measure the thickness of the dielectric film, two frequencies of small sinusoidal voltage (∼1 V) signals were applied to an electrically floated planar type probe, which is positioned at chamber wall surface, and the amplitudes of the currents and the phase differences between the voltage and current were measured. By using an equivalent sheath circuit model including a sheath capacitance, the dielectric thickness can be obtained. Experiments were performed in various plasma condition, and reliable dielectric film thickness was obtained regardless of the plasma properties. In addition, availability in commercial chamber for plasma enhanced chemical vapor deposition was verified. This study is expected to contribute to the control of etching and deposition processes and optimization of periodic maintenance in semiconductor manufacturing process.

J0420306 音響共鳴現象と超音波パルスエコー法を利用したソフトマテリアルの膜厚と音速の同時計測

We propose a new measurement method for simultaneously measuring thickness and sound velocity for soft materials such as a conductive polymer film and stacked induced pluripotent stem cells (iPS cells). Using the 75 MHz underwater-type ultrasound transducer, simultaneous thickness and sound velocity measurement has been carried out by combining the acoustic resonant spectroscopy and pulse-echo measurement. The advantage of this method is that the thickness can be derived without using the known value of sound velocity. The thickness of the conductive polymer film and the stacked iPS cells on metal substrate are measured at 10.4 μm and 16.0 μm, respectively. The thickness of conductive polymer and the staked iPS cells agrees well with the reference measured by the confocal laser microscope. T These results indicate that the developed measurement method can be one of the potential candidates for the real-time thickness measurement for the soft materials. For future work, the thickness of living iPS cells should be measured in real time. Using this method, we would like to figure out the relationship between the stacked state and the differentiation of iPS cells.

A viscoelastic-based model for TFC membranes flux reduction during compaction

During the initial operation of membranes, large reduction in flux can occur due to membrane structure compaction. Since compaction results in the deformation of the polymer matrix of the membrane, it has been proposed that the flux decline can be described by viscoelastic models. However, the proposed models so far did not provide direct connection between flux decline and membrane compaction. Indeed, for thin film composite (TFC) membranes, the reported deformation, as measured by real-time thickness measurements, occurs at a much faster rate than the accompanying flux reduction during compaction. We attribute this discrepancy to the complex structure of TFC membranes which must be properly addressed by the viscoelastic model. The current study proposes the use of the Voigt–Wiechert model to describe the compressive strain experienced by TFC membranes. This model provides the advantage of deconvoluting the response of the TFC membrane. Based on this model, a new relation is proposed to describe the flux decline during compaction. The model is tested on strain/flux data and found to give excellent predictions. The model was also found to represent the flux decline better than the traditional power law relation. The model also describes the increase in salt rejection observed during compaction. Insight into the physical properties of the active layer is introduced based on the model fitting results.