共查询到20条相似文献,搜索用时 15 毫秒
1.
A novel flip-chip assembly technique by means of electroplating at a low processing temperature has been developed. Mesoscopic
gears, made of nickel with 1500 μm in diameter and 250 μm in height, have been bonded to glass substrate. The bonding process
is conducted by nickel electroplating at 50 °C with a current density at 53.3 A/m2. The nickel electrolyte is found to penetrate about 100 μm from the perimeter to the center of the gear and form a good bond.
This process can be applied to the integration of high-aspect-ratio microstructures with substrates that have pre-fabricated
microelectronics massively and in parallel. As such, it provides a powerful way to achieve the integration of meso- and microscopic
electromechanical systems.
Received: 7 July 1999/Accepted: 30 June 2000 相似文献
2.
The artificially constructed materials based split ring resonators (SRRs) may have exotic electromagnetic properties and have
received growing interest in recent years. Moreover, the resonance frequency shift of this material is extraordinarily sensitive
to the changes in the capacitance of SRR, which makes SRR suit for microwave thin-film sensing applications. Based on such
principle, the tip-shaped SRR metamaterial is presented as thin-film sensor in this paper to reduce device size and resonance
frequency as well as to improve the Q-factor. The structure is placed inside an X-band waveguide with dimensions of 22.86 mm × 10.16 mm × 12.8 mm
to investigate resonance frequency shift in different cases by numerical method. In contrast to the traditional structures,
the tip-shaped design exhibits a miniaturization and sharper dip on resonance in their transmission spectra. Furthermore,
the proposed sensor can deliver the sensitivity level of 16.2 MHz/μm and less than a 2 μm nonlinearity error when the uniform
benezocyclobutene films from 100 nm to 50 μm thick are coated onto the fixed structure. These results indicate that the proposed
thin-film sensor has high sensitivity and low nonlinearity error, and make it great promising application for wireless sensors
in future. 相似文献
3.
High-current density DC magenetohydrodynamics micropump with bubble isolation and release system 总被引:1,自引:1,他引:0
One of the major challenges for integrated Lab-on-a-Chip (LOC) systems is the precise control of fluid flow in a micro-flow
cell. Magnetohydrodynamics (MHD) micropumps which contain no moving parts and capable of generating a continuous flow in any
ionic fluid offer an ideal solution for biological applications. MHD micropumping has been demonstrated by using both AC and
direct current (DC) currents by a number of researchers with varying degrees of success. However, current MHD designs based
on DC do not meet the flow rate requirements for fully automated LOC applications (>100 μl/min). In this research, we introduce
a novel DC-based MHD micropump which effectively increases flow rate by limiting the effects of electrolysis generated bubbles
at the electrode–electrolyte interface through isolation and a mechanism for their release. Gas bubbles, particularly, hydrogen
generated by high current density at the electrodes are the main culprit in low experimental flow rate compared with theoretical
values. These tiny bubbles coalesce in the flow channel thus obstructing the flow of fluid. Since hydrolysis is inevitable
with DC excitation, compartmentalized electrode channels with bubble isolating and coalescence retarding mechanisms and bubble
release systems are implemented to prevent the coalescence of these bubbles and minimize their effects on flow rate. In this
novel design called bubble isolation and release system, flow rate of up to 325 μl/min is achieved using 1 M NaCl solution
in DC mode with potentials of 5 V and current density of about 5,000 A/m2 for a main channel of 800 μm × 800 μm cross-section and 6.4 mm length. 相似文献
4.
Chien-Hsing Chen Tzu-Chien Tsao Wan-Yun Li Wei-Chih Shen Chung-Wei Cheng Jaw-Luen Tang Chun-Ping Jen Lai-Kwan Chau Wei-Te Wu 《Microsystem Technologies》2010,16(7):1207-1214
A novel fiber-optic localized plasma resonance (FO-LPR) sensor composed of a U-shape optical fiber was proposed and demonstrated
in this study. The U-shape optical fiber was fabricated by a femtosecond laser micromachining system. The dimensions of the
U-shape zone were 100 μm in depth measured from the surface of the polymer jacket layer, 80 μm in width in the jacket layer,
60 μm in width in the cladding layer. The total length is 5 mm. After laser annealing treatment, the average surface roughness
was 205.8 nm as determined by Atom Force Microscope (AFM). The exposed surface of the U-shape fiber was modified with self-assembled
gold nanoparticles to produce the FO-LPR sensor. The response of the sensor shows that the signal increases linearly with
increasing refractive index. The sensor resolution of the sensor was determined to be 1.06 × 10−3 RIU. 相似文献
5.
The purpose of this study is to fabricate a stainless steel protector for a weak fiber sensor after first stripping the polymer
outer-layer off the fiber. In addition to protecting the fiber sensor, the stainless steel protector is required to connect
the detection target and the sensor which requires drilling holes in the protector. We accomplished this by electrochemical
micromachining the stainless steel protector using pulse DC, using 1 kV/m, 6.62% weight concentration of NaCl electrolyte
solution, 500 rpm anode rotating rate, a 5 MHz pulse frequency, a 50% duty factor, and 6 min of machining time with a ring
cathode gave the best results, producing an average hole-radius of 231.36 μm. 相似文献
6.
I. S. Akhatov J. M. Hoey O. F. Swenson D. L. Schulz 《Microfluidics and nanofluidics》2008,5(2):215-224
A micro-capillary system capable of generating a focused collimated aerosol beam (CAB) is demonstrated both theoretically
and experimentally. The approach is based on a manifestation of the Saffman force where high velocity (∼100 m/s) aerosol particles,
flowing through a micro-capillary (d ∼ 100 μm and l ∼ 1 cm), migrate perpendicular to the centerline of the capillary. Upon exiting the micro-capillary system, the particles
maintain momentum, and when the aerosol is comprised of solid-in-liquid dispersions such as Ag nanoparticle ink, the CAB approach
enables printing of advanced materials features with linewidth ≤ 10 μm. 相似文献
7.
This work explores the microstructure and magnetic properties of electrodeposited Co-Zn thin films. Using pulse-reverse electroplating
technique, Co-rich Co-Zn films are deposited 0.4–1.9 μm thick from aqueous sulfate-based baths at low temperature (55°C).
The influence of current density (25–100 mA/cm2) and electrolyte Zn concentration (0–0.28 M) on the microstructure and magnetic properties are investigated. All of the Co-Zn
films exhibit higher out-of-plane coercivity, as compared to in-plane. With increasing current density, the out-of-plane coercivity
decreases from 50 to 40 kA/m (628–500 Oe). The influence of the Zn concentration in the electrolyte is more pronounced, affecting
the grain size, film composition, and magnetic properties. The best magnetic properties were obtained from a bath with 0.21 M
Zn and an average current density of 25 mA/cm2, resulting in a Co97Zn3 composition and an out-of-plane coercivity of 92 kA/m (1,160 Oe). 相似文献
8.
This paper presents a micro roller embossing process for patterning large-area substrates of laminated green ceramic tapes.
The aim of this research is to develop a large-area microstructure formation technique for green ceramic substrates using
a thermal roller laminator, which is compatible with screen printing apparatus. A thin film nickel mold was developed via
photolithographic patterning and nickel electroplating on a 75-μm-thick nickel film. The mold had an effective panel size
of 150 mm × 150 mm with the height of plated protrusive patterns being about 38 μm. Formation of micro patterns was successfully
demonstrated over the whole panel area on laminated green ceramic tapes using roller embossing. Micro patterns for inductors,
heaters as well as interconnection with 50 μm line-width were embossed on green ceramic substrates. By means of tuning process
parameters including roller temperature, applied pressure and feeding speed, we have demonstrated that micro roller embossing
is a promising method for patterning large-area green ceramic substrates. 相似文献
9.
Chia-Yen Lee Zgen-Hui Chen Hsien-Tseng Chang Chih-Yung Wen Chiang-Ho Cheng 《Microsystem Technologies》2009,15(8):1171-1177
This study designs, fabricates, and characterizes a novel micro electromagnetic actuator comprising a PDMS diaphragm, a polyimide-coated
copper micro coil, and a permanent magnet. When an electrical current is passed through the micro coil, a magnetic force is
induced between the coil and the magnet which causes the diaphragm to deflect, thereby creating an actuation effect. The experimental
results demonstrate that the diaphragm deflection can be accurately controlled by regulating the current passed through the
micro coil. It is shown that the maximum diaphragm deflection within elastic limits is 150 μm; obtained by passing a current
of 0.6 A through a micro coil with a line width of 100 μm. The micro actuator proposed in this study is easily fabricated
and is readily integrated with existing bio-medical chips due to its planar structure. 相似文献
10.
An integrated flow-cell for full sample stream control 总被引:1,自引:1,他引:0
In this study, we present a novel three-dimensional hydrodynamic sheath flow chip that allows full control of a sample stream.
The chip offers the possibility to steer each of the four side sheath flows individually. The design of the flow-cell exhibits
high flexibility in creating different sample stream profiles (width and height) and allows navigation of the sample stream
to every desired position inside the microchannel (vertical and horizontal). This can be used to bring the sample stream to
a sensing area for analysis, or to an area of actuation (e.g. for cell sorting). In addition, we studied the creation of very
small sample stream diameters. In microchannels (typically 25 × 40 μm2), we created sample stream diameters that were five
to ten times smaller than the channel dimensions, and the smallest measured sample stream width was 1.5 μm. Typical flow rates
are 0.5 μl/min for the sample flow and around 100 μl/min for the cumulated sheath flows. The planar microfabricated chip,
consisting of a silicon–glass sandwich with an intermediate SU-8 layer, is much smaller (6 × 9 mm2) than the previously presented
sheath flow devices, which makes it also cost-effective. We present the chip design, fluidic simulation results and experiments,
where the size, shape and position of the sample stream have been established by laser scanning confocal microscopy and dye
intensity analysis. 相似文献
11.
Temperature gradients aroused from the Joule heating in a non-uniform electrical field can induce inhomogeneities of electric
conductivity and permittivity of the electrolyte, thus causing an electrothermal force that generates flow motion. A 2D numerical
investigation of a micromixer, utilizing electrothermal effect to enhance its mixing efficiency, is proposed in this paper.
Results for temperature and velocity distributions, as well as sample concentration distribution are obtained for an electrolyte
solution in a microchannel with different pairs of electrodes under AC potentials with various frequencies. Numerical solutions
were first carried out for one pair of electrodes, with a length of 10 μm separated by a gap of 10 μm, on one side wall of
a microchannel having a length of 200 μm and a height of 50 μm. It is found that the electrothermal flow effect, in the frequency
range for which Coulomb force is predominant, induces vortex motion near the electrodes, thus stirring the flow streams and
enhancing its mixing efficiency. If more than one pair of electrodes is located on the opposite walls of the microchannel,
the mixing efficiency depends on the AC potential applied pattern and the electrodes arrangement pattern. The distance between
two pairs of electrodes on two opposite walls is then optimized numerically. Sample mixing efficiencies, using KCl solutions
as the working fluid in microchannels with different number of electrodes pairs at optimal electrodes arrangement pattern,
are also investigated. If root mean squared voltages of 10 V in an AC frequency range of 0.1–10 MHz are imposed on 16 pairs
of electrodes separated at an optimal distance, the numerical results show that a mixing efficiency of 98% can be achieved
at the end of the microchannel having a length of 700 μm and a height of 50 μm at Re = 0.01 Pe
C = 100, and Pe
T = 0.07. However, the mixing efficiency decreases sharply at a frequency higher than 10 MHz owing to the drastically decrease
in the Coulomb force. 相似文献
12.
Wei-Hsu Chang Schellin B. Obermeier E. Yu-Chung Huang 《Journal of microelectromechanical systems》2006,15(3):548-552
Deep etching of n-type 6H-SiC using a two-step etching process has been studied. First, anodization of 6H-SiC in an HF electrolyte (2 wt.%) without ultraviolet light is applied to form a deep porous layer with the desired dimensions. Then, a thermal oxidation process is used to oxidize this porous layer. The oxidized layer is then removed in a concentrated HF solution. In the experiments, the etching parameters electrolyte concentration and current density are optimized in order to obtain a uniform pore size and hence, a smooth etched surface. After adjusting these parameters, the porous layer formation experiments are carried out at 20/spl deg/C in a 2 wt.% HF electrolyte using a current density of 50 mA/cm/sup 2/. The corresponding porous layer formation rate is about 1.1 /spl mu/m/min. To demonstrate the capabilities of this SiC bulk micromachining process, deep circular cavities are fabricated in n-type 6H-SiC substrates. 相似文献
13.
This paper describes the development of metallic bipolar plate fabrication using micro-electroforming process for mini-DMFC
(direct methanol fuel cell) stacks. Ultraviolet (UV) lithography was used to define micro-fluidic channels using a photomask
and exposure process. Micro-fluidic channels mold with 300 μm thick and 500 μm wide were firstly fabricated in a negative
photoresist onto a stainless steel plate. Copper micro-electroforming was used to replicate the micro-fluidic channels mold.
Following by sputtering silver (Ag) with 1.2 μm thick, the metallic bipolar plates were completed. The silver layer is used
for corrosive resistance. The completed mini-DMFC stack is a 3.5 × 3.5 cm2 fuel cell stack including a 1.5 × 1.5 cm2 MEA (membrane electrode assembly). Several MEAs were assembly into mini-DMFC stacks using the completed metallic bipolar
plates. All test results showed the metallic bipolar plates suitable for mini-DMFC stacks. The maximum output power density
is 9.3 mW/cm2 and current density is 100 mA/cm2 when using 8 vol.% methanol as fuel and operated at temperature 30°C. The output power result is similar to other reports
by using conventional graphite bipolar plates. However, conventional graphite bipolar plates have certain difficulty to be
machined to such micro-fluidic channels. The proposed micro-electroforming metallic bipolar plates are feasible to miniaturize
DMFC stacks for further portable 3C applications. 相似文献
14.
Replication of precise polymeric microlens arrays combining ultra-precision diamond ball-end milling and micro injection molding 总被引:1,自引:0,他引:1
S. Kirchberg L. Chen L. Xie G. Ziegmann B. Jiang K. Rickens O. Riemer 《Microsystem Technologies》2012,18(4):459-465
A simple and novel combination of ultra-precision diamond ball-end milling and micro injection molding technique is described
to produce precise microlens arrays out of polycarbonate (PC), polymethylmethacrylate (PMMA) as well as polystyrene (PS).
The microlens arrays consist of 100 lenses in a 10 × 10 array with a lens radius of 273 μm, a lens diameter of 300 μm and
a lens depth of 45 μm. Pitch between the lenses is fixed at 800 μm. The injection molding parameters were optimized to get
precise microlens geometries with low surface roughness. The results show a precise diamond milled mold insert and injection
molded microlens arrays with minor deviations in radius and surface roughness of the microlenses, particularly for microlens
arrays out of PMMA. 相似文献
15.
A. Deutschinger U. Schmid M. Schneider W. Brenner H. Wanzenböck B. Volland Tzv. Ivanov I. W. Rangelow 《Microsystem Technologies》2010,16(11):1901-1908
A micromachined electro-thermal gripper, first introduced by Ivanova et al. (Microelectron Eng 83:1393–1395, 2006), represents a promising candidate for the manipulation and handling of micro or even
nano-scaled objects. To further optimize the performance of the device, a detailed electrical and mechanical characterization
is needed. Due to the so-called duo-action gripper approach (i.e., a separate actuator for closing and opening action) these
investigations focused on the maximum (minimum) opening width being 11.5 μm (3.3 μm), while in rest position a value of 4 μm
is feasible. The maximum, electrical input power is limited to 80 mW/actuator element, resulting in a current density of up
to 1.27 MA cm−2 in the corresponding metal layers. When applying, however, larger current densities the probability of device failure increases
substantially as in combination with an enhanced temperature of about 200°C electromigration effects occur in the metallization.
Furthermore, the cut-off frequency and parasitic effects during actuation such as the z-deflection and the increase in length
of each arm both showing values of up to 3 μm have been investigated as a function of operation parameters. Finally, the tips
of the gripper were sharpened using Focused Ion Beam technique to a radius of less than 1 μm for gripping operations in space-restricted
environments or for the manipulation or handling of sub-μm scaled objects. 相似文献
16.
Chee Tiong Lim Hong Yee Low Johnson K. K. Ng Wen-Tso Liu Yong Zhang 《Microfluidics and nanofluidics》2009,7(5):721-726
A photolithography technique using SU-8 and PDMS was developed to fabricate three-dimensional hemispherical structures. This
technique utilized a mask-aligner and normal binary coded photomasks to generate hemispherical pits on SU-8, followed by PDMS
molding to obtain an array of dome-shaped structures. Using this technique, a microfluidic device was fabricated with a patterning
area that consisted of an array of 5 μm wells and dome-shaped structures with 10 μm diameter and 6 μm height. Encoded microbeads,
6 μm in size, were immobilized and patterned in the microfluidic device under flow conditions and a DNA hybridization experiment
was performed to demonstrate the incorporation of encoded beads that would enable a high level of multiplexing in bioassays. 相似文献
17.
The integration of a PDMS membrane within orthogonally placed PMMA microfluidic channels enables the pneumatic actuation of
valves within bonded PMMA–PDMS–PMMA multilayer devices. Here, surface functionalization of PMMA substrates via acid catalyzed
hydrolysis and air plasma corona treatment were investigated as possible techniques to permanently bond PMMA microfluidic
channels to PDMS surfaces. FTIR and water contact angle analysis of functionalized PMMA substrates showed that air plasma
corona treatment was most effective in inducing PMMA hydrophilicity. Subsequent fluidic tests showed that air plasma modified
and bonded PMMA multilayer devices could withstand fluid leakage at an operational flow rate of 9 μl/min. The pneumatic actuation
of the embedded PDMS membrane was observed through optical microscopy and an electrical resistance based technique. PDMS membrane
actuation occurred at pneumatic pressures of as low as 10 kPa and complete valving occurred at 14 kPa for ~100 μm by 100 μm
channel cross-sections. 相似文献
18.
MEMS micro fluxgate sensors with mutual vertical excitation coils and detection coils 总被引:1,自引:1,他引:0
As a classic Earth magnetic field sensor, fluxgate magnetic sensors have great potential applications in many fields. This
paper presents a new 3D micro-solenoid fluxgate magnetic sensor based on the MEMS technique. The excitation coils were placed
vertically to the detection coils on the chip plane, around a rectangular shaped magnetic core. Polyimide was used to insulate
coils and magnetic core. Width of copper conductor lines is 50 μm, and line space is 50 μm. The design of such fluxgate magnetic
sensor followed second harmonic signal selecting method. Phase-lock amplifier was used to get second harmonic signal output
by detection coils. The linear range of 0–80 μT with sensitivity of 6.7 V/T was achieved from the fabricated sensor with excitation
current of 430 mA and the operational frequency of 40 KHz. As the excitation current was 470 mA, linear range of 0–50 μT with
sensitivity of 21.7 V/T was achieved. 相似文献
19.
Design and fabrication of SU-8 micro optic fiber holder with cantilever-type elastic microclips 总被引:1,自引:1,他引:0
The optic alignment module containing out-of-plane 3D micro lenses, and micro optic fiber holders have been fabricated using
tilted UV lithography technique in water with SU-8 photoresist (Ling and Lian in Proc SPIE 4979:402–409, 2007). Each holder is a circumscribed quadrilateral formed by a V-groove and pairs of fixed microclips, which will hold the fiber
in position through the elastic deformation when the fiber is inserted. Since these microclips were fixed cantilever beams
and its effective beam length, the distance between the fixed end of the beam and beam–fiber contact point, is very short
(~62.5 μm), the stress on the beam is high even under a small (few microns) deformation. The inserted optical fiber was either
too loose to lose its alignment accuracy, or too tight causing the clips to break because of dimensional tolerance. It becomes
very difficult, if not impossible, to use them in practical applications. Therefore, the key issue of fabricating optical
alignment module is to have a suitable stiffness of microclips with an appropriate deformation during the fiber insertion,
which can provide enough force to hold the fiber for accurate alignment and avoid introducing neither significant viscous
deformation nor the damage to the clips. In this paper, a novel technique to fabricate SU-8 cantilever beam as elastic clamping
device in optical fiber holder is proposed. Simulation based on SU-8 material properties indicates that for a 250-μm-long,
50-μm-thick SU-8 beam the clamping force per unit beam width will range from 10 to 100 Newton/m as the deflection increased
from 1.4 to 14 μm. This predicted performance is comparable to or even better than that of existing silicon nitride microclips
in optical fiber holding application [Bostock et al. in J Micromech Microeng 8(4):343–360, 1998]. By using a two-mask process, we have fabricated free-end cantilever beams as fiber holding clips. In order to have longer
beams over V-groove, the slots in the V-groove were introduced, which allow the beams extended deeper into the sloped V-groove
walls. The micro alignment module with 250-μm-length cantilever beams as microclips for housing 125-μm-diameter optical fibers
has been successfully fabricated using a 300-μm-thick SU-8 photoresist layer by a two-mask UV lithography processes. This
approuch offers significant advantages over other techniques with respect to costs of material, simple in equipment, and easy
in manufacture. These optical fiber holders with elastic microclips combined with pre-aligned out-of-plane 3D micro lenses
make it possible that to build an integrated micro optic system with precise alignment accuracy on a wafer-scale. 相似文献
20.
Khaled Metwally Laurent Robert Samuel Queste Bernard Gauthier-Manuel Chantal Khan-Malek 《Microsystem Technologies》2012,18(2):199-207
Microfluidics on foil is gaining momentum due to a number of advantages of employing thin films combined with the capability
of cost-effective high-volume manufacturing of devices. In this work, ultra-thin, flexible Y-microreactors with microchannels
of 100 μm width and 30 μm depth were fabricated in thermoplastic polymer foils. The fluidic pattern was hot roll embossed
in 125 μm thick poly-methyl-methacrylate (PMMA) and 130 μm thick cyclic-olefin-copolymer (COC) films using a dry-etched microstructured
silicon wafer as a flat embossing tool in a laminator. The sealing of the channels was performed with two different techniques,
one based on lamination of SU8 dry film resist (DFR) and the other one based on spin-coated poly-dimethylsiloxane (PDMS).
Testing of the interconnected microreactor was carried out using two dye colorant solutions to demonstrate mixing. 相似文献