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Illustration of the flip-chip bonding technique for a prototype MOEMS structure. (a) Cut view for wafer bonding and passive alignment. (b) Schematic view.
Source publication
Using flip-chip bonding techniques with micromachined conductive
polymer bumps and passive alignment techniques with electroplated side
alignment pedestal bumps, a prototype microoptoelectromechanical systems
(MOEMS) structure for optical input/output (I/O) couplers has been
designed, fabricated and characterized. A top MOEMS substrate has
through...
Contexts in source publication
Context 1
... photodetectors and top wafer were independently fabri- cated, and then assembled using flip-chip bonding techniques with micromachined conductive polymer bumps and passive alignment techniques with electroplated alignment pedestal bumps. Fig. 8(a) illustrates the flip-chip bonding technique for the building of the prototype MOEMS structure. Thermoplastic conductive polymers (Epo-Tek K/5022-115BE) used in this work possess the property of melting or re-wetting when heated to a specific temperature (150 C). After substrate was pre-heated to approximately 20 C above the thermo- ...
Context 2
... sive alignment does not bring the complexities inherent in operating devices during the bonding and packaging. So that, the advantages of the alignment pedestal is reductions in packaging time and cost [5], [6]. Piece-to-feature passive alignment technique was used for high-efficiency coupling of optoelectronic devices to optic fiber, as shown in Fig. 8(b). The flip-chip packaging techniques for MOEMS structure proposed in this work offer a simple passive-aligned flip-chip bonding process. The good passive alignment between photodetectors and through holes is based on dicing accuracy of flip-chip pho- todetectors and precise formation of side alignment pedestal bumps. To obtain smaller ...
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... For large area sensor skin, for instance, integrating electronics and sensors becomes indispensable to manage interconnect complexity. Many polymeric materials could, thus, find applications in future MEMS including conducting polymers, electro active polymers like polypyrrole, photo pattern able gelatin, shrinkable polystyrene film, shape memory polymers, and piezoelectric polymers such as polyvinylidene fluoride (PVDF) [95][96][97][98][99][100][101][102][103][104][105]. ...
The impact of 'engineered-nanomaterials' in cost effective fabrication of micro/nanosensors, and on site energy harvesting devices using 'printing technology' for Internet of things (IoT) applications has been assessed in this technology review after analyzing the ongoing progresses reflected in market research forecasts and the anticipated future projections. Being actively involved in the study of 'engineered nanomaterials' using inorganic, organic, and biomolecular building-blocks for improving the characteristics of microelectronic/microsystems (MEMS/NEMS) based sensors/actuators, theoretical/experimental studies of 1, 2, and 3D nanomaterials along with the developments of low-cost printing technology for fabricating the electronic/optoelectronic devices and circuits on plastics, paper, and textiles, an attempt has been made in this review to examine the impact of these novel nanomaterials and their printing technology to enhance the capabilities of the related enabling technologies of IoT applications. Novel designs of supra molecular nano-building-blocks to realize hierarchically organized molecular complexes responding to single/multi stimuli with additional electronic intelligence realized by low-cost printing of sensors and actuators along with the wireless connectivity on flexible substrates in the background, possible answer for meeting the gigantic requirement of trillion devices by 2020 has been searched in this study. Combining the cost effective printing of active devices using polymeric molecules with known electronic/optoelectronic transport properties and 2D-layered materials like graphene and other graphene like materials, is found promising to pursue by addressing to the problems of compatible patterning for devices/circuits fabrications. A number of practical issues are discussed in which the basic concept of 'materials by design' is foreseen to play a major role in the coming times. Biomimetically produced supra molecular-complexes deserve special attentions for realizing printed sensors/actuators/devices and interfaces to generate big-data for cloud based decisions initiating local control actions better in IoT proliferations in future.
... The pull-in voltage can be reduced if the membrane is made up of a flexible material instead of a rigid one. SU-8(MicroChem Corp.)[4] can be realized with out any significant etching steps [5], [6]. As shown inTable.I, SU-8 is highly flexible and is not brittle. ...
In this paper we present a thorough analysis of
a low pull-in voltage Capacitive Micromachined Ultrasonic
Transducer (CMUT) using SU-8 as the membrane material.
It is designed to operate at 1 MHz frequency that has a
wide range of applications including the imaging of deeper
organs. We also propose a simple state-of-the-art fabrication
methodology for the same. As compared to the standard
Silicon Nitride CMUTs, the proposed structure gives the same
electromechanical coupling coefficient with lower membrane
dimensions and low pull-in voltage which in turn results in
reduced area and power consumption. Moreover the proposed
fabrication methodology is a low temperature process which
makes it CMOS compatible
... Each trap segment between two type 1 dies is fabricated by bonding type 2 dies together, which transmit the electric potential through the segment. The ability to fabricate micro patterns and structural material for microelectromechanical systems (MEMS) using the SU-8 photolithography has been previously demonstrated [5][6][7]. This resist has been shown to be particularly suitable for thick film applications because of its thermal stability and low optical absorption [8]. ...
Acquiring a portable high density charged particles trap might consist of an
array of micro-Penning-Malmberg traps (microtraps) with substantially lower end
barriers potential than conventional Penning-Malmberg traps [1]. We report on
the progress of the fabrication of these microtraps designed for antimatter
storage such as positrons. The fabrication of large length to radius aspect
ratio (1000:1) microtrap arrays involved advanced techniques including
photolithography, deep reactive ion etching (DRIE) of silicon wafers to achieve
through-vias, gold sputtering of the wafers on the surfaces and inside the
vias, and thermal compression bonding of the wafers. This paper describes the
encountered issues during fabrication and addresses geometry errors and
asymmetries. In order to minimize the patch effects on the lifetime of the
trapped positrons, the bonded stacks were gold electroplated to achieve a
uniform gold surface. We show by simulation and analytical calculation that how
positrons confinement time depends on trap imperfections.
... Over the past two decades, SU-8 photoresist has been widely used for fabrication of micro-and nano-structures by transferring patterns in a film mask into a layer of SU-8 film during photolithography [1]. The SU-8 has been applied not only in the fabrication of molds [2,3], but also in the structural material for microelectromechanical systems (MEMS) [4]. Its high chemical and mechanical stability enables various applications, such as cantilevers, membranes and microchannels [4]. ...
... where V EBR and V SU−8 are the total volume of EBR and SU-8 on the wafer, respectively. From equation (4), we calculated the molar fraction of each component and then computed the viscosity of the mixture according to equation (3). In general, as the volume fraction of the EBR over the SU-8 increases, the viscosity of the mixture decreases. ...
... SU-8 processing conditions for six different samples(1)(2)(3)(4)(5)(6). ...
This paper proposes a new SU-8 fabrication process to simultaneously remove edge bead and tiny air bubbles by spraying out edge bead removal (EBR) fluid over the entire surface of photoresist. In particular, the edge bead and air bubbles can cause an air gap between a film mask and a photoresist surface during UV exposure. The diffraction effect of UV light by the air gap leads to inaccurate and non-uniform SU-8 patterns. In this study, we demonstrate a simple method using EBR treatment to simultaneously eliminate the edge bead at the edge of wafer and tiny air bubbles inside SU-8. The profiles of thickness variation of SU-8 films with/without the EBR treatment are measured. The results show that the proposed EBR treatment can successfully remove the edge bead and air bubbles over the entire SU-8 films. The average pattern uniformity of SU-8 is improved from 50.5% to 11.3% in the case of 200 µm thickness. This method is simple and inexpensive, compared to a standard EBR process, because it does not require specialized equipment and it can be applied regardless of substrate geometry (e.g. circular wafer and rectangular slide glass).
... Indium tin oxide ͑ITO, 100 nm thick͒ electrodes were deposited by DC sputter on the patterned glass substrate, and a lift-off process was performed to finalize the conductive ITO electrodes. 15,16 An oxide insulation layer ͑300 nm͒ was grown over the electrodes using PECVD. Then a square window ͑40ϫ 40 m 2 ͒ was etched over the ground electrode in the narrow channel to allow an electric contact to the droplets. ...
This study reports a droplet-based microfluidic device for on-demand electrostatic droplet charging and sorting. This device combines two independent modules: one is a hydrodynamic flow focusing structure to generate water-in-oil droplets, and the other is the two paired-electrodes for charging and sorting of the droplets. Depending on the polarity on charging electrodes, water-in-oil droplets can be electrostatically charged positively or negatively, followed by automatic real-time electric sorting. This approach will be useful when preformed droplets, with a positive, a negative, or with no charge, need to be manipulated for further on-chip droplet manipulation.
... The characterized vertical coupling structures allow the routing of millimeter-wave signals between the adjacent levels of a 3D module created by stacking self-aligning micromachined shielding and membrane layers. This fabrication technique would also potentially allow for the attachment of MMICs directly onto the membranes via a flip-chip technique [2,38], which relies on a low-cost, lead-free, fluxless flip-chip technology based on the use of conductive polymers [38][39][40][41][42][43]. As shown in Figure 2, this would enable the back-side of the MMIC to be attached to a thermally conductive base-substrate while the high-frequency electrical connections are made directly to the membrane supported transmission lines. ...
The preliminary design concept, for a low-loss, high-bandwidth electromagnetically coupled vertical transition for use as a via between adjacent levels of a 3D-MCM based on membrane-supported striplines with micro-machined shielding, is presented. The design methodology, modeling using Ansoft HFSS and simulated results are presented and together represent a complete electrical characterization of the vertical transition. The simulated insertion loss of these structures is shown to be as low as 0.12 dB at 60 GHz with a 44 GHz 1 dB bandwidth. Besides studying the vertical transition, the analysis is extended to identify the range of directional coupling which can be achieved using this type of structure, which is shown to be greater than 3 dB. The structures studied rely on a versatile micromachining technique for the fabrication of the micro-shielding which allows for the conformal packaging of lines and devices, with the ultimate aim of realizing 3D system-in-a-package type modules. The concept and proposed fabrication techniques for these modules, including methods of °ip-chip MMIC attachment are detailed.
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We present simultaneous fabrication of micro-deflector and optical waveguide using femtosecond two photon polymerization technique. Parallelepiped-shaped waveguide was created which may serve as beam deflectors for layerto- layer optical interconnection. The quality of the polymerized surface was characterized by atomic force microscope (AFM) which shows the root-mean-square (RMS) roughness is no greater than 5nm. The propagation and reflection loss of the fabricated waveguide at wavelength of 850nm are estimated to be
... Polymer flip chip process utilizes Ag filled thermoset and/or thermoplastic polymers in conjunction with stencil printing processes to form polymer flip chip devices [1]. Micro-electro-mechanical systems (MEMS) or micro-opto-electro-mechanical systems (MOEMS) [6] requires low temperature fabrication techniques which is particularly suited for polymer flip chip applications. With polymer flip chip, direct interconnection using conductive bumps merges level 1 & 2 interconnects to realize maximum space conservation, high package density, short conducting path, low lead inductance, high assembly yield and high performance. ...
Polymer flip chip process utilizes Ag filled thermoset and/or thermoplastic polymers, in combination with stencil printing processes to form polymer bump interconnects of flip chip IC devices (Estes, 1998). Nevertheless, slumping behavior of conventional polymer interconnect material during bumping process on the wafer chip has constrained the bump height achieved by the most common stencil printing to 50mum (Kulesza et al., 1997). A bumping process to form fine pitch, high aspect ratio polymer flip chip bumps without slumping was developed by producing a through-hole PDMS micro-transfer mould on a metallized wafer (Wong, et al., 2003). In this paper, a MEMS chip (Lee, et al., 2003) was packaged by the PDMS micro-transfer mould technique to evaluate the performance of the interconnection method. Flip chip assembly process was then performed on the printed circuit board (PCB) and some functionality tests was conducted afterwards. The designed dimension of the polymer bump is 150mum in diameter, 90mum in height, and at a 245mum pitch. Bump adhesion force was measured and found to be about 40gram. Electrical conductivity test was also conducted after PCB assembly as preliminary reliability test of the whole assembly process. Results showed that the MEMS chip was functioning well with new polymer bumping method. With this bumping approach, intrinsic slumping problem of the conductive polymer paste is resolved. This low temperature fabrication technique is an important development for MEMS packaging
... T HE use of flip-chip bonding technology has inherent advantages of improved reliability, lower costs, and higher input/output (I/O) density in less packaging space [1], [2]. Flip-chip bonding is preferred for the mounting or inverting of photonic devices on optical communication systems or recently emerging bio/chemical micro total analysis systems ( -TAS), where precise input/output coupling is required between photonic devices and optical waveguides or optic fibers, as shown in Fig. 1 [3], [4]. In developing flip-chip bonding techniques for sensor and actuator systems, optical MEMS, or optical interconnections, the most difficult problems usually come from the precision formation of bumps and the lower temperature for flip-chip bonding. ...
... Fig. 8(a) through holes is based on dicing accuracies of flip-chip photodetectors and precise formation of copper pedestal bumps. Fig. 8(c) is the SEM picture of a finger structure of GaAs MSM photodetector passive-aligned to the through hole on the top MOEMS substrate [3]. To permit the ease of alignment with the optical beam reflected from the mirror, detector area of m m was designed. ...
Using micromachining techniques with thick photoresists, a new
conductive polymer flip-chip bonding technique that achieves both a low
processing temperature and a high bumping alignment resolution has been
developed in this work. By the use of UV-based photolithography with
thick photoresists, molds for the flip-chip bumps have been patterned,
filled with conductive polymers, and then removed, leaving molded
conductive polymer bumps. After flip-chip bonding with the bumps, the
contact resistances measured for 25 μm-high bumps with 300
μm×300 μm area and 400 μm×400 μm area were 35
mΩ and 12 mΩ respectively. The conductive polymer flip-chip
bonding technique developed in this work shows a very low contact
resistance, simple processing steps, a high bumping alignment resolution
(<±5 μm), and a lower bonding temperature (~170°C).
This new bonding technique has high potential to replace conventional
flip-chip bonding technique for sensor and actuator systems,
bio/chemical μ-TAS, optical MEMS, OE-MCM's, and electronic system
applications
... In recent years, conductive polymers have generated considerable interest as possible solder replacements in a variety of surface mount applications. Compared with traditional solder flip-chip bonding, the polymer flip-chip bonding technique has the added benefits of a lower process temperature, environmental cleanliness and higher manufacturing efficiency [12] [13]. Further, polymer bumps are compliant, unlike their rigid solder counterparts, resulting in an improved tolerance of thermal stress caused by mismatched coefficients of thermal expansion (CTE) between the flip-chip bonded materials. ...
... low contact resistance, simple processing steps and high bumping alignment resolution (<5 µm) [12] [13]. Further, a lower bonding temperature of approximately 170 • C makes polymer flip-chip bonding techniques compatible with polymer substrates, which are relatively inexpensive but cannot be processed at high temperatures needed for the conventional solder-based technique [14] [15] [16]. ...
The object of this thesis is to develop a new packaging method to mount silicon micro pressure sensors into 1.67 mm diameter neonatal catheters to measure blood pressure. A new polymer flip-chip bonding method on a flexible Kapton film has been developed and applied to dual lumen neonatal catheters integrated with silicon micro pressure sensors. Flip chip bonding technique has inherent advantages of miniaturization, improved reliability and cost reduction. This polymer flip-chip bonding technique requires a low temperature process and improved tolerance of thermal stress which are very desirable for mounting micro sensors or micro actuators on lower-cost flexible polymer substrates for medical applications. The silicon micro pressure sensors, which are mounted on a flexible Kapton film with metal lines for neonatal catheter, have been fully characterized in both gas and liquid environments, indicating that the packaging was satisfactory rugged for catheter use. Text (abstract in HTML; full text in PDF). System requirements: Macintosh or IBM PC-compatible computer; World Wide Web browser; Adobe Acrobat Reader. Mode of access: World Wide Web. Title from electronic thesis title page (viewed Oct. 19, 2004). Thesis (M.S.)--University of Cincinnati, 2004. Includes bibliographical references. Includes abstract.
