scholarly journals Lift-off Effect for Capacitive Imaging Sensors

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4286 ◽  
Author(s):  
Xiaokang Yin ◽  
Chen Li ◽  
Zhen Li ◽  
Wei Li ◽  
Guoming Chen
Keyword(s):  
Fibre Composite ◽  
Dielectric Materials ◽  
Hybrid Structure ◽  
Fe Analysis ◽  
Measurement Sensitivity ◽  
Capacitance Variation ◽  
Complex Measurement ◽  
Lift Off ◽  
Imaging Sensors ◽  
Imaging Performance

Capacitive Imaging (CI) sensors are capable of non-detecting both surface and hidden defects in dielectric materials and characterizing conducting surfaces through a relatively thick insulation layer. However, the complex Measurement Sensitivity Distribution (MSD) of CI sensors render the sensor capacitance variation with lift-off highly non-linear, which may lead to misinterpretation of defect indications. This work systematically studied the lift-off effect using both Finite Element (FE) analysis and experimental approaches. Sensor MSD was used as a tool to predict the imaging performance. Normalized Variation Ratio (NVR) was introduced and used to characterise sensor responses due to defects for a CI sensor. Both the FE analysis and experiments suggest that the lift-off effect for a CI sensor is specimen type and condition dependent. For a given defect, the NVR may vary non-monotonically with increased lift-offs. A case study on a glass-fibre composite/aluminium hybrid structure with multiple artificial defects demonstrated the feasibility of defects discrimination using multiple CI scans with increased lift-offs.

scholarly journals Design of 2D Sparse Array Transducers for Anomaly Detection in Medical Phantoms

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5370
Author(s):  
Xiaotong Li ◽  
Anthony Gachagan ◽  
Paul Murray
Keyword(s):  
Fibre Composite ◽  
Evaluation Criteria ◽  
Array Configuration ◽  
Array Pattern ◽  
Array Transducer ◽  
Random Array ◽  
Spiral Array ◽  
Imaging Performance ◽  
Tissue Mimicking Material ◽  
Tube Structure

Aperiodic sparse 2D ultrasonic array configurations, including random array, log spiral array, and sunflower array, have been considered for their potential as conformable transducers able to image within a focal range of 30–80 mm, at an operating frequency of 2 MHz. Optimisation of the imaging performance of potential array patterns has been undertaken based on their simulated far field directivity functions. Two evaluation criteria, peak sidelobe level (PSL) and integrated sidelobe ratio (ISLR), are used to access the performance of each array configuration. Subsequently, a log spiral array pattern with −19.33 dB PSL and 2.71 dB ISLR has been selected as the overall optimal design. Two prototype transducers with the selected log spiral array pattern have been fabricated and characterised, one using a fibre composite element composite array transducer (CECAT) structure, the other using a conventional 1–3 composite (C1–3) structure. The CECAT device demonstrates improved coupling coefficient (0.64 to 0.59), reduced mechanical cross-talk between neighbouring array elements (by 10 dB) and improved operational bandwidth (by 16.5%), while the C1–3 device performs better in terms of sensitivity (~50%). Image processing algorithms, such as Hough transform and morphological opening, have been implemented to automatically detect and dimension particles located within a fluid-filled tube structure, in a variety of experimental scenarios, including bespoke phantoms using tissue mimicking material. Experiments using the fabricated CECAT log spiral 2D array transducer demonstrated that this algorithmic approach was able to detect the walls of the tube structure and stationary anomalies within the tube with a precision of ~0.1 mm.

scholarly journals A contest of sensors in close range 3D imaging: performance evaluation with a new metric test object

2014 ◽  
Vol XL-5 ◽  
pp. 277-284 ◽  
Author(s):  
M. Hess ◽  
S. Robson ◽  
A. Hosseininaveh Ahmadabadian
Keyword(s):  
Performance Evaluation ◽  
Test Object ◽  
3D Imaging ◽  
Image Quality Assessment ◽  
Close Range ◽  
Imaging Sensors ◽  
Imaging Performance ◽  
Processing Steps ◽  
3D Digitizing ◽  
Digital Assets

An independent means of 3D image quality assessment is introduced, addressing non-professional users of sensors and freeware, which is largely characterized as closed-sourced and by the absence of quality metrics for processing steps, such as alignment. A performance evaluation of commercially available, state-of-the-art close range 3D imaging technologies is demonstrated with the help of a newly developed Portable Metric Test Artefact. The use of this test object provides quality control by a quantitative assessment of 3D imaging sensors. It will enable users to give precise specifications which spatial resolution and geometry recording they expect as outcome from their 3D digitizing process. This will lead to the creation of high-quality 3D digital surrogates and 3D digital assets. The paper is presented in the form of a competition of teams, and a possible winner will emerge.

scholarly journals Rabi-like splitting and refractive index sensing with hybrid Tamm plasmon-cavity modes

2022 ◽  
Author(s):  
Shuvendu Jena ◽  
Raj Bahadur Tokas ◽  
Sudhakar Thakur ◽  
Dinesh V Udupa
Keyword(s):  
Refractive Index ◽  
Dielectric Materials ◽  
Hybrid Structure ◽  
Lower Hybrid ◽  
Detection Accuracy ◽  
Hybrid Mode ◽  
Refractive Index Sensing ◽  
Spacer Layer ◽  
Splitting Energy ◽  
Cavity Thickness

Abstract Rabi-like splitting and self-referenced refractive index sensing in hybrid plasmonic-1D photonic crystal structures have been theoretically demonstrated. The coupling between Tamm plasmon and cavity photon modes are tuned by incorporating a low refractive index spacer layer adjacent to the metallic layer to form their hybrid modes. Anticrossing of the modes observed at different values of spacer layer thickness validates the strong coupling between the two modes and causes Rabi-like splitting with different splitting energy. The modes coupling has been supported by coupled mode theory. Rabi-like splitting energy decreases with increasing number of periods (N) and refractive index contrast (η) of two dielectric materials used to make the 1D photonic crystals, and the observed variation is explained by an analytical model. Angular and polarization dependency of the hybrid modes shows that the polarization splitting of the lower hybrid mode is much stronger than that of the upper hybrid mode. On further investigation, it is seen that one of the hybrid modes remains unchanged while other mode undergoes significant change with varying the cavity medium. This nature of the hybrid modes has been utilized for designing self-referenced refractive index sensors for sensing different analytes. For η=1.333 and N=10 in a hybrid structure, the sensitivity increases from 51 nm/RIU to 201 nm/RIU with increasing cavity thickness from 170 nm to 892 nm. For the fixed cavity thickness of 892 nm, the sensitivity increases from 201 nm/RIU to 259 nm/RIU by increasing η from 1.333 to 1.605. The sensing parameters such as detection accuracy, quality factor, and figure of merit for two different hybrid structures ([η=1.333, N=10] and [η=1.605, N=6]) have been evaluated and compared. The value of resonant reflectivity of one of the hybrid modes changes considerably with varying analyte medium which can be used for refractive index sensing.

FABRICATION OF FLEXIBLE FIELD-EFFECT TRANSISTORS ON 25 μm PEN FOIL

2011 ◽  
Vol 20 (04) ◽  
pp. 775-786
Author(s):  
FRANÇOIS FURTHNER ◽  
MÁRIA PÉTER ◽  
BAS VAN DER PUTTEN ◽  
GERWIN H. GELINCK ◽  
ERWIN R. MEINDERS ◽  
...  
Keyword(s):  
Field Effect ◽  
Dielectric Material ◽  
Field Effect Transistors ◽  
Dielectric Materials ◽  
Organic Polymer ◽  
Polyethylene Naphthalate ◽  
Material Source ◽  
Main Challenge ◽  
Metal Insulator Metal ◽  
Lift Off

The development of high performance thin-film transistors on flexible plastic substrates is of great importance for the manufacturing and industrialization of flexible electronic devices, such as flexible displays. Here we present different approaches to fabricate bottom-gate field-effect transistors on 25 μm heat stabilized polyethylene naphthalate (PEN) foil using photolithography and solution processing. The flexibility and dimensional instability of the substrate constituted the main challenge during manufacturing. We developed a novel method to handle the foils during processing by reversibly attaching them onto 6 inch Si wafers. The so-called foil-on-carrier assembly showed excellent flatness (about 1 μm) and good dimensional stability and tolerance towards the different processing steps up to 160°C. Transistors were made either using an organic polymer or an inorganic oxide as gate dielectric material. Source and drain gold electrodes were patterned using standard photoresist patterning followed by wet etching, or by lift-off. The feature sizes in the transistors were downsized from 5 μm to sub-micrometer to improve the performance. In order to achieve structures with high resolution, all functional layers were patterned using a commercial wafer stepper (PAS5500/100D). The two dielectric materials used and the two ways of making the source-drain resulted in four different metal-insulator-metal (MIM) stacks. The MIM stacks were characterized by optical microscopy, scanning electron microscopy and four point resistance measurements. Registration accuracies below 0.5 μm were found over the whole wafer. Transistor fabrication was finished by depositing pentacene derivatives from solution.

A Generic Strategy to Assess and Mitigate Chip Package Interaction Risk Factors for Semiconductor Devices with Ultra-low k Dielectric Materials in Back End of Line

2017 ◽  
Vol 2017 (1) ◽  
pp. 000163-000171 ◽  
Author(s):  
Frank Kuechenmeister ◽  
Dirk Breuer ◽  
Holm Geisler ◽  
Christian Klewer ◽  
Bjoern Boehme ◽  
...  
Keyword(s):  
Flip Chip ◽  
Dielectric Materials ◽  
Advanced Technology ◽  
Wafer Level ◽  
Contributing Factors ◽  
Related Factors ◽  
Wafer Level Packaging ◽  
Generic Strategy ◽  
Lift Off ◽  
Technology Nodes

Abstract This paper describes a systematic approach to the identification of primary contributing factors to the Chip Package Interaction (CPI) risk and reveals the mitigation strategy successfully applied by GLOBALFOUNDRIES. The strategy includes modeling at bump and package level, gathering experimental data on blanket dielectric back end of line (BEoL) films, collecting data on wafer material with a complete BEoL stack, and finally using readouts on the package level. Advanced measurement methods generate data on the wafer level to achieve fast turn-around times. These methods include: (i) Dual-Cantilever Beam (DCB) test, (ii) Modified Edge Lift-off Test (MELT), (iii) Single Pillar Shear Test (SPST) and (iv) Bump Assisted BEoL Stability Indentation (BABSI) tests. The paper describes the methodology to gather data on the wafer level with a complete BEoL metallization stack that assesses the BEoL integrity. Furthermore, the package level thermomechanical modeling approach is discussed. The model has been used to determine the critical factors on BEoL stress/strain during the flip-chip assembly reflow processes. Silicon design-related factors in the BEoL that contribute to the risk for CPI related failures were investigated and options to reduce the CPI risk are discussed. Finally the paper reveals package level qualification data flip-chip CSP and wafer level packaging Fan-In for advanced technology nodes.

scholarly journals Broadband Stacked Antenna Design with Hybrid Structure for C-band Communication

2019 ◽  
Vol 8 (10) ◽  
pp. 3510-3516
Keyword(s):  
Dielectric Material ◽  
Impedance Matching ◽  
Dielectric Materials ◽  
Hybrid Structure ◽  
Impedance Bandwidth ◽  
Patch Structure ◽  
Low Profile ◽  
Resonance Frequencies ◽  
Low Profile Antennas ◽  
Microstrip Feed

Two low profile antennas using FR4 and Rogers RT/duroid 5880 as dielectric materials are proposed in this manuscript. To obtain the broadband response the strip-slot hybrid structure is introduced. The two antennas proposed in this manuscript consist of four strips that are segregated through three narrow tapered slots. Using the aperture couple microstrip feed line proper impedance matching is obtained and the slotted patch structure is excited. The simulated bandwidth of 45% is obtained by using the Rogers RT/duroid 5880 as dielectric material with stacked patch structure and gain obtained to be 9.02dB resonating at 4.2GHz of frequency. Proposed design using FR4 as the dielectric material has two resonance frequencies at 4.8GHz and 6.2GHz. The simulated bandwidth of 50% at 4.8GHz and 38.71% at 6.2GHz is obtained with gain of 6.040dB at 4.8GHz. A prototype of the same antenna using the FR4 as dielectric material is also constructed and tested, the tested results shows an impedance bandwidth of 21.87%

scholarly journals Lift-off protocols for thin films for use in EXAFS experiments

2013 ◽  
Vol 20 (3) ◽  
pp. 426-432 ◽  
Author(s):  
S. Decoster ◽  
C. J. Glover ◽  
B. Johannessen ◽  
R. Giulian ◽  
D. J. Sprouster ◽  
...  
Keyword(s):  
Thin Films ◽  
Sample Preparation ◽  
Dielectric Materials ◽  
Amorphous Semiconductors ◽  
Preparation Methods ◽  
X Ray ◽  
X Ray Scattering ◽  
Sample Preparation Procedure ◽  
Lift Off ◽  
X Ray Absorption

Lift-off protocols for thin films for improved extended X-ray absorption fine structure (EXAFS) measurements are presented. Using wet chemical etching of the substrate or the interlayer between the thin film and the substrate, stand-alone high-quality micrometer-thin films are obtained. Protocols for the single-crystalline semiconductors GeSi, InGaAs, InGaP, InP and GaAs, the amorphous semiconductors GaAs, GeSi and InP and the dielectric materials SiO2and Si3N4are presented. The removal of the substrate and the ability to stack the thin films yield benefits for EXAFS experiments in transmission as well as in fluorescence mode. Several cases are presented where this improved sample preparation procedure results in higher-quality EXAFS data compared with conventional sample preparation methods. This lift-off procedure can also be advantageous for other experimental techniques (e.g.small-angle X-ray scattering) that benefit from removing undesired contributions from the substrate.

The influence of confocal microscope design on imaging performance

1993 ◽  
Vol 51 ◽  
pp. 144-145
Author(s):  
C J R Sheppard
Keyword(s):  
Image Quality ◽  
Fluorescence Imaging ◽  
Confocal Microscope ◽  
Industrial Applications ◽  
Three Dimensions ◽  
Design Parameters ◽  
Weak Signals ◽  
Size And Shape ◽  
Imaging Performance ◽  
Fundamental Limitation

The confocal microscope is now widely used in both biomedical and industrial applications for imaging, in three dimensions, objects with appreciable depth. There are now a range of different microscopes on the market, which have adopted a variety of different designs. The aim of this paper is to explore the effects on imaging performance of design parameters including the method of scanning, the type of detector, and the size and shape of the confocal aperture.It is becoming apparent that there is no such thing as an ideal confocal microscope: all systems have limitations and the best compromise depends on what the microscope is used for and how it is used. The most important compromise at present is between image quality and speed of scanning, which is particularly apparent when imaging with very weak signals. If great speed is not of importance, then the fundamental limitation for fluorescence imaging is the detection of sufficient numbers of photons before the fluorochrome bleaches.

A new method for the observation of Type II magnetic contrast

1990 ◽  
Vol 48 (4) ◽  
pp. 764-765
Author(s):  
R.P. Ferrier ◽  
S. McVitie
Keyword(s):  
Domain Walls ◽  
Incident Beam ◽  
Objective Lens ◽  
Type Ii ◽  
Backscattering Coefficient ◽  
Magnetic Contrast ◽  
Standard Geometry ◽  
Backscattered Electron ◽  
Imaging Performance ◽  
Good Probe

Type II magnetic contrast was first observed by Philibert and Tixier and relies on the change in the effective backscattering coefficient due to interaction of the scattered electrons within the specimen and the local magnetic induction (for a review see Tsuno). Depending on the tilt of the specimen and the position of the backscattered electron detector(s), contrast due to the presence of either or both domains and domain walls can be obtained; in the case of the latter, the standard geometry is for the specimen to be normal to the incident beam and the detectors are positioned above it and close to the optic axis. This is the geometry adopted in our studies, which used a JEOL 2000FX with a special split objective lens polepiece; this permitted the specimen to be in magnetic field-free space, the separate lens gaps above and below allowing good probe forming capabilities combined with excellent Lorentz imaging performance. A schematic diagram is shown in Fig. 1.

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