1,623 research outputs found
2D Detectors for Particle Physics and for Imaging Applications
The demands on detectors for particle detection as well as for medical and
astronomical X-ray imaging are continuously pushing the development of novel
pixel detectors. The state of the art in pixel detector technology to date are
hybrid pixel detectors in which sensor and read-out integrated circuits are
processed on different substrates and connected via high density interconnect
structures. While these detectors are technologically mastered such that large
scale particle detectors can be and are being built, the demands for improved
performance for the next generation particle detectors ask for the development
of monolithic or semi-monolithic approaches. Given the fact that the demands
for medical imaging are different in some key aspects, developments for these
applications, which started as particle physics spin-off, are becomming rather
independent. New approaches are leading to novel signal processing concepts and
interconnect technologies to satisfy the need for very high dynamic range and
large area detectors. The present state in hybrid and (semi-)monolithic pixel
detector development and their different approaches for particle physics and
imaging application is reviewed
Thermo-mechanical analysis of flexible and stretchable systems
This paper presents a summary of the modeling and technology developed for flexible and stretchable electronics. The integration of ultra thin dies at package level, with thickness in the range of 20 to 30 μ m, into flexible and/or stretchable materials are demonstrated as well as the design and reliability test of stretchable metal interconnections at board level are analyzed by both experiments and finite element modeling. These technologies can achieve mechanically bendable and stretchable subsystems. The base substrate used for the fabrication of flexible circuits is a uniform polyimide layer, while silicones materials are preferred for the stretchable circuits. The method developed for chip embedding and interconnections is named Ultra Thin Chip Package (UTCP). Extensions of this technology can be achieved by stacking and embedding thin dies in polyimide, providing large benefits in electrical performance and still allowing some mechanical flexibility. These flexible circuits can be converted into stretchable circuits by replacing the relatively rigid polyimide by a soft and elastic silicone material. We have shown through finite element modeling and experimental validation that an appropriate thermo mechanical design is necessary to achieve mechanically reliable circuits and thermally optimized packages
Trends in Pixel Detectors: Tracking and Imaging
For large scale applications, hybrid pixel detectors, in which sensor and
read-out IC are separate entities, constitute the state of the art in pixel
detector technology to date. They have been developed and start to be used as
tracking detectors and also imaging devices in radiography, autoradiography,
protein crystallography and in X-ray astronomy. A number of trends and
possibilities for future applications in these fields with improved
performance, less material, high read-out speed, large radiation tolerance, and
potential off-the-shelf availability have appeared and are momentarily matured.
Among them are monolithic or semi-monolithic approaches which do not require
complicated hybridization but come as single sensor/IC entities. Most of these
are presently still in the development phase waiting to be used as detectors in
experiments. The present state in pixel detector development including hybrid
and (semi-)monolithic pixel techniques and their suitability for particle
detection and for imaging, is reviewed.Comment: 10 pages, 15 figures, Invited Review given at IEEE2003, Portland,
Oct, 200
Integralni pristup sustavima energetske elektronike
Today\u27s power electronics systems are typically manufactured using non-standard parts, resulting in labor-intensive manufacturing processes, increased cost and poor reliability. As a possible way to overcome these problems, this paper discusses an integrated approach to design and manufacture power electronics systems to improve performance, reliability and cost effectiveness. Addressed in the paper are the technologies being developed for integration of both power supplies and motor drives. These technologies include the planar metalization to eliminate bonding wires, the integration of power passives, the integration of current sensors, the development of power devices to facilitate integration as well as to improve performance, and the integration of necessary CAD tools to address the multidisciplinary aspects of integrated systems. The development of Integrated Power Electronics Modules (IPEMs) is demonstrated for two applications: (1) 1 kW asymmetrical half-bridge DC-DC converter and (2) 1–3 kW motor drive for heating, ventilation and air conditioning (HVAC). Electrical and thermal design tradeoffs of IPEMs and related enabling technologies are described in the paper.Današnji sustavi energetske elektronike se obično proizvode iz nestandardnih dijelova. Posljedica toga je laboratorijska proizvodnja elektroničkih učinskih pretvarača, povećani troškovi i smanjena pouzdanost. Jedan od mogućih načina prevladavanja ovih poteškoća jest integralni pristup projektiranju i proizvodnji sustava energetske elektronike. Posebice se razmatraju tehnologije razvijene za integraciju učinskih krugova i motora. Ove tehnologije uključuju postupke planarne metalizacije za izbjegavanje žičanih vodova, integraciju pasivnih dijelova učinskih krugova, integraciju strujnih senzora, te razvoj takvih poluvodičkih komponenata koje olakšavaju integraciju i poboljšavaju karakteristike uređaja. Pri projektiranju, zbog multidisciplinarnih aspekata integriranih sustava, treba primijeniti nužne CAD alate. Razvoj integriranih modula elektroničkih učinskih pretvarača (engl. integrated power electronics modules, IPEM) ilustriran je na dvije primjene: (1) istosmjerni pretvarač snage 1 kW u asimetričnom polumosnom spoju i (2) elektromotorni pogon snage 1 . . . 3 kW za grijanje, ventilaciju i klimatizaciju (engl. heating, ventilation and air conditioning, HVAC). Na IPEM-u objašnjeni su projektantski i tehnološki kompromisi električkog i toplinskog projekta
Mechanics of Non Planar Interfaces in Flip-Chip Interconnects
With the continued proliferation of low cost, portable consumer electronic
products with greater functionality, there is increasing demand for electronic packaging that is smaller, lighter and less expensive. Flip chip is an essential enabling technology for these products. The electrical connection between the chip I/O and substrate is achieved using conductive materials, such as solder, conductive epoxy, metallurgy bump
(e.g., gold) and anisotropic conductive adhesives. The interconnect regions of flip-chip packages consists of highly dissimilar materials to meet their functional requirements. The mismatches in properties, contact morphology and crystal orientation at those material interfaces make them vulnerable to failure through delamination and crack
growth under various loading patterns. This study encompasses contact between deformable bodies, bonding at the asperities and fracture properties at interfaces formed by the interconnects of flip-chip packages. This is achieved through experimentation and modeling at different length scales, to be able to capture the detailed microstructural features and contact mechanics at interfaces typically found in electronic systems
Pixel Detectors for Tracking and their Spin-off in Imaging Applications
To detect tracks of charged particles close to the interaction point in high
energy physics experiments of the next generation colliders, hybrid pixel
detectors, in which sensor and read-out IC are separate entities, constitute
the present state of the art in detector technology. Three of the LHC detectors
as well as the BTeV detector at the Tevatron will use vertex detectors based on
this technology. A development period of almost 10 years has resulted in pixel
detector modules which can stand the extreme rate and timing requirements as
well as the very harsh radiation environment at the LHC for its full life time
and without severe compromises in performance. From these developments a number
of different applications have spun off, most notably for biomedical imaging.
Beyond hybrid pixels, a number of trends and possibilities with yet improved
performance in some aspects have appeared and presently developed to greater
maturity. Among them are monolithic or semi-monolithic pixel detectors which do
not require complicated hybridization but come as single sensor/IC entities.
The present state in hybrid pixel detector development for the LHC experiments
as well as for some imaging applications is reviewed and new trends towards
monolithic or semi-monolithic pixel devices are summarized.Comment: 24 pages, 16 figure
The effect of co-planarity variation on anisotropic conductive adhesive assemblies
Anisotropic Conductive Adhesives (ACAs) consist of a
polymer adhesive matrix containing fine conductive particles
dispersed either randomly, or more rarely in an ordered way.
The primary objective of this experimental research was to
understand the effects of a non-uniform bond thickness due to
non co-planarity of the component or substrate terminations
in ACA assemblies. This has been achieved through
measurements of the conductivity variations of ACA joints in
a number of ACA assemblies, where the component bump
plane and substrate plane were deliberately held in different
degrees of relative rotation from parallel during adhesive
cure. Measurements of the joint resistances versus rotational
angle, for a constant bonding force, were made for 10 levels
of rotation of the chips relative to the substrates. The results
showed that the resistances of the joints in the assemblies
exhibited three distinct types of behaviour: stable joint
resistances; gradually increasing resistances and unstable
resistances. In conclusion, it is shown that ACA joints are
very sensitive to the uniformity of the bond thickness, as the
larger the rotations were, the lower and less uniform the joint
conductivities were, however, the joints were uniform if the
rotation angles were controlled within certain limits
Evaluation of Anisotropic Conductive Films Based on Vertical Fibers for Post-CMOS Wafer-Level Packaging
In this paper, we investigate the mechanical and electrical properties of an anisotropic conductive film (ACF) on the basis of high-density vertical fibers for a wafer-level packaging (WLP) application. As part of the WaferBoard, a\ud
reconfigurable circuit platform for rapid system prototyping,\ud
ACF is used as an intermediate film providing compliant and\ud
vertical electrical connection between chip contacts and a top surface of an active wafer-size large-area IC. The chosen ACF is first tested by an indentation technique. The results show that the elastic–plastic deformation mode as well as the Young’s modulus and the hardness depend on the indentation depth. Second, the efficiency of the electrical contact is tested using a uniaxial compression on a stack comprising a dummy ball grid array (BGA) board, an ACF, and a thin Al film. For three bump diameters, as the compression increases, the resistance values decrease before reaching low and stable values. Despite the BGA solder bumps exhibit plastic deformation after compression, no damage is found on the ACF film. These results show that vertical fiber ACFs can be used for nonpermanent bonding in a WLP application
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