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1.
Reproductive techniques like injection molding or embossing of feedstock provide microstructures of a wide variety of materials
for a reasonable price to micro system technology. In this paper, the dependencies and barriers to produce high aspect ratio
structures by micro metal injection molding are described; some results of embossing of metal powder based feedstocks are
presented, too. The investigations show different influencing parameters for reaching high aspects ratios. The main factor
is the used powder, finer powders allow higher aspect ratios. Moreover, the binder system, the feedstock (mixture of powder
and binder) and the quality of the injection mold influence the reproduction process.
Received: 10 August 2001/Accepted: 24 September 2001 相似文献
2.
Multi-layered ceramic substrates with embedded micro patterns are becoming increasingly important, for example, in harsh environment
electronics, enabling microsystems and microfluidic devices. Fabrication of these embedded micro patterns, such as micro channels,
cavities and vias, is a challenge. This study focuses on the process aspects of patterning micro features on low temperature
co-firable ceramic (LTCC) green substrates using micro hot embossing. Green ceramic tapes that possessed near-zero shrinkage
in the x–y plane were used, six layers of which were stacked and laminated as a substrate. The process parameters that impact on the
embossing fidelity were investigated and optimized in this study. Micro features with channel-width as small as several micrometers
were formed on green ceramic substrates. The dynamic thermo-mechanical analysis indicated that extending the holding time
at a certain temperature range would harden the substrates with little effect on improving the embossing fidelity. Ceramic
substrates with embossed micro patterns were obtained after co-firing; the shrinkage ratios of the embossed depth and channel-width
were 8–15 and 12–17%, respectively. The changes of pitches between two embossed channels were within ±1.0% due to the interlocking
effect of the ceramic tapes. 相似文献
3.
A. Schneider B. Su T. W. Button L. Singleton O. Wilhelmi S. E. Huq P. D. Prewett R. A. Lawes 《Microsystem Technologies》2002,8(2-3):88-92
In this paper results are presented from a range of experiments to explore the feasibility of inserting a ceramic material
PZT (lead zirconium titanate) into different kinds of high-aspect-ratio resist moulds. Polymethylmethacrylate (PMMA) and SU-8
on silicon substrates and free-standing SU-8 membranes with micro-cavities or through-holes (defined by X-ray lithography)
have been used as moulding medium. Processing conditions for the resist materials including pre-bake, exposure, post-bake,
development and stripping have been compared. The advantages of different types of resist mould for the LIGA process has been
evaluated. Additionally a comparison of photosensitivity of PMMA and SU-8 has been carried out. Using a range of load pressures
(5 to 60 MPa), appropriate conditions for PZT embossing into resist moulds have been determined (ensuring minimum void formation
in the final PZT structures). In the final form, SU-8 moulds have been removed by laser ablation. This is the first reporting
of high-aspect-ratio ceramic microstructures fabricated using a combination of SU-8 moulds and PZT embossing.
Received: 10 August 2001/Accepted: 24 September 2001 相似文献
4.
Masaharu Takahashi Yoichi Murakoshi Ryutaro Maeda Kohei Hasegawa 《Microsystem Technologies》2007,13(3-4):379-384
Micro/Nano imprinting or hot embossing is currently a target of interest for industrial production of micro and Nano devices
for the low cost aspect. In Fluidic MEMS (Micro Electromechanical Systems) applications, polymer materials have been widely
employed for their low cost to fabricate the economical products (Becker and Heim in Sens Acuators A 83:120–135, 2000; Becker and Gaertner in Mol Biotechnol 82:89–99, 2001). However glasses are much more suitable for the higher temperature applications or under the stronger chemical environments.
Moreover UV absorption of glass materials is much less than that of polymers, which is the advantage for bio-analysis. In
Optical MEMS as well, glasses are good candidate materials for the better optical properties, such as high refractive index,
low UV absorption and others. Although wet etching of glasses is widely employed for fabrication of fluidic MEMS devices,
the wet etching is not satisfactory for the low machining resolution, the isotropic etched profile and poor roughness of the
fabricated structures. Dry etching of glasses is then an alternative for Micro/Nano structuring, but the etching rate is extremely
low (order of 0.1 μm/min) and the cost is too high because of the expensive RIE (Reactive Ion Etching) facility. Above mentioned
is the reason why we are interested in hot embossing or imprinting of glasses of Micro/Nano scale. In our previous study,
Micro/Nano imprinting was developed for Pyrex glasses using GC (Glassy Carbon) mold prepared by FIB machining (Takahashi et
al. in Symposium on DTIP 2004 pp 441–446, 2004). The disadvantage of FIB machining is limited area of etching. The typical area of FIB is less than several hundreds micrometer
square. This is the reason why we tried the large area of embossing using GC mold fabricated by dicing machine. Micro hot
embossed test structures were successfully demonstrated with good fidelity. Fabricated micro structures can be applied for
fabrication of microchamber array for PCR (Akagi et al. in Sci Techol Adv Mater 5:343–349, 2004; Nagai et al. in Anal Chem 73:1043–1047, 2001). 相似文献
5.
Today, hot embossing and injection molding belong to the established plastic molding processes in microengineering. Based
on experimental findings, a variety of microstructures have been replicated so far using the above processes. However, with
increasing requirements regarding the embossing surface and the simultaneous decrease of the structure size down into the
nanorange, increasing know––how is needed to adapt hot embossing to industrial standards. To reach this objective, a German–Canadian
cooperation project has been launched to study hot embossing theoretically by a process simulation and experimentally. The
present publication shall report about an important aspect––the determination of friction during the demolding of microstructures. 相似文献
6.
Wear resistant tools for reproduction technologies produced by micro powder metallurgy 总被引:3,自引:0,他引:3
Micro system technology (MST) needs cost effective production techniques and for the development of new MST products also
new materials are necessary. Reproduction technologies have been developed for large scale production which are allow processing
a broad scope of materials (plastic, ceramic and metal). For these, tools are needed which have to fulfil a lot of requirements.
In this paper the results of an evaluation of micro powder metallurgy (MPM) as a technology to produce highly productive tools
and moulds for structuring of plastics and metals by reproduction, possibly also for difficult materials as glass, are presented.
Moulds made of iron, stainless steel and hard metal of different designs were produced and quality issues investigated. Results
of hot embossing and injection moulding of metal and plastic using these inserts produced by micro powder metallurgy are given.
Received: 15 May 2001 / Accepted: 4 July 2001 相似文献
7.
1-3 Piezocomposites offer many advantages over monolithic transducers, however replicating their fine scale structure is demanding.
Viscous polymer (VP) embossing is a technique that has already been demonstrated as being capable of achieving the small feature
size and high aspect ratio features that are required for piezocomposites. However, the process utilises a lost mould technique
and is therefore limited by the ability to make cost effective sacrificial moulds. Hot embossing has been identified as a
technique that is suitable for replicating these moulds, and piezocomposites made from them are presented here. This paper
dimensionally characterises the piezocomposites through each stage of the VP embossing process. The piezocomposites described
here have feature sizes of 30 μm, volume fractions 0.5 and operating frequencies of 12.3 MHz. For the first time piezocomposites
have been made by VP embossing into cost effective moulds. 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.
J. A. van Kan P. G. Shao K. Ansari A. A. Bettiol T. Osipowicz F. Watt 《Microsystem Technologies》2007,13(5-6):431-434
P-beam writing (proton beam writing), a direct write 3D nano lithographic technique has been employed for the production of
X-ray masks in a single step fabrication process, with high aspect ratios and extremely smooth absorber edges. P-beam writing
employs a focused MeV proton beam scanned in a predetermined pattern over a resist (e.g. PMMA or SU-8), which is subsequently
chemically developed. P-beam writing in combination with electroplating appears ideally suited to directly write X-ray masks
with nano sized features, high aspect ratios, small lateral feature sizes, and smooth and vertical sidewalls. Sub 100 nm resist
structures with aspect ratios up 160 have been produced, as well as metallic (nickel) structures down to the 100 nm level.
Preliminary tests on p-beam written X-ray test masks show that Ni stencils can be fabricated with a thickness of 2–20 μm,
smooth side walls, feature details down to 1 μm, and aspect ratios up to 20. 相似文献
10.
C. K. Chung W. J. Chang Y. F. Kuo C. L. Hsiao K. Y. Weng 《Microsystem Technologies》2002,8(4-5):318-322
A novel design for bidirectional fluidic motion has been demonstrated which is widely used in the biochip or microfluidic
component. Two miniaturized Venturi pumps as well as pneumatic servo system are designed to easily control the bidirectional
fluidic motion by simple fabrication. The pumping velocity is 0.86 μl/min at a 2.75 slpm (standard liter per minute) air flow
read from mass flow controller (MFC) for totally 4.3 μl blue ink in a 300 μm wide by 300 μm deep channel. The higher airflow,
the faster fluidic pumping speed. Numerical simulation is performed to correlate the experimental data of fluidic speed and
air flow in microchannel. The test chip with two Venturi pumps and channel was batchedly fabricated by silicon deep reactive
ion etching (RIE) and glass anodic bonding. The ICP LIGA process is also investigated after deep RIE followed the electroforming
and hot embossing.
Received: 10 August 2001/Accepted: 24 September 2001 相似文献
11.
Microfabrication of single-use plastic microfluidic devices for high-throughput screening and DNA analysis 总被引:8,自引:1,他引:7
A. Gerlach G. Knebel A.E. Guber M. Heckele D. Herrmann A. Muslija TH. Sshaller 《Microsystem Technologies》2002,7(5-6):265-268
Modern drug discovery and genomic analysis depend on rapid analysis of large numbers of samples in parallel. The applicability
of microfluidic devices in this field needs low cost devices, which can be fabricated in mass production. In close collaboration,
Greiner Bio-One and Forschungszentrum Karlsruhe have developed a single-use plastic microfluidic capillary electrophoresis
(CE) array in the standardized microplate footprint. Feasibility studies have shown that hot embossing with a mechanical micromachined
molding tool is the appropriate technology for low cost mass fabrication. A subsequent sealing of the microchannels allows
sub-microliter sample volumes in 96-channel multiplexed microstructures.
Received: 16 May 2001 / Accepted: 3 July 2001 相似文献
12.
L. A. Domeier M. Gonzales J. Hachman J. M. Hruby R. Janek A. M. Morales 《Microsystem Technologies》2002,8(2-3):78-82
Novel technology is presented which allows the rapid replication of electroforming plastic micromolds. This technique incorporates
microscreens into hot embossing or injection molding processes to produce sacrificial molds with conducting bases and insulating
sidewalls. Both contiguous and non-contiguous features can be electroformed from these molds. Process parameters including
the microscreen geometry and the use of multiple porous metal inserts are discussed.
Received: 10 August 2001/Accepted: 24 September 2001 相似文献
13.
Molding technologies associated with fabricating macro scale polymer components such as injection molding and hot embossing
have been adapted with considerable success for fabrication of polymer microparts. While the basic principles of the process
remain the same, the precision with which the processing parameters need to be controlled especially in the case of molding
high aspect ratio (HAR) polymer microparts into polymer sheets is much greater than in the case of macro scale parts. It is
seen that the bulk effects of the mold insert fixture and molding machine have a dominant influence on the molding parameters
and that differences in material parameters such as the glass transition temperature (T
g) of polymer sheets are critical for the success and typically differ from sheet to sheet. This makes it very challenging
to establish standard processing parameters for hot embossing of sheet polymers. In the course of this paper, a methodology
for developing a hot embossing process for HAR microstructures based on known material properties and considering the cumulative
behavior of mold, material, and machine will be presented. Using this method force–temperature–deflection curves were measured
with the intent of fine tuning the hot embossing process. Tests were carried out for different materials using a dummy mold
insert yielding information that could be directly transferred to the actual mold insert with minimum development time and
no risk of damage to the actual microstructures. 相似文献
14.
J. Michael Fried 《Computing and Visualization in Science》2009,12(3):125-135
We present an adaptive finite element algorithm for segmentation with denoising of multichannel images in two dimensions,
of which an extension to three dimensional images is straight forward. It is based on a level set formulation of the Mumford–Shah
approach proposed by Chan and Vese in (JVCIR 11:130–141,(2000); IEEE Trans Image Proces 10(2):266–277, (2001); Int J Comp
Vis 50(3):271–293, (2002)) In case of a minimal partition problem an exact solution is given and convergence of the discrete
solution towards this solution is numerically verified. 相似文献
15.
A methacrylate copolymer combining chemically amplified concept and casting technique was developed as a novel thick photoresist
for the UV-LIGA process. Photoresist layers up to 500 μm in thickness can be fabricated easily. Microstructures fabricated
by the novel thick photoresist were demonstrated. At present, the ring-shape microstructures with 150 μm tall and 15 μm wide
have been realized and the calculated aspect ratio is 10.
Received: 10 August 2001/Accepted: 24 September 2001 相似文献
16.
R. Bandorf H. Lüthje K. Schiffmann T. Staedler A. Wortmann 《Microsystem Technologies》2002,8(1):51-54
This paper deals with the fabrication and characterisation of friction and wear reduced nano-films for micro actuator applications.
For this investigation films of diamond-like-carbon (DLC), metal doped Me-DLC, carbon-nitride CN
x
, boron-nitride BN and alumina Al2O3 films have been applied in the thickness range of 20–500 nm. The hardness of those coatings varied between 10 and 60 GPa.
Micromechanical and microtribological properties of nano-coatings have been characterized by a modified scanning probe microscope.
Besides this a novel micro tester for abrasive wear measurement of nano coatings was used. Friction of micro-contact areas
was measured by use of a pin-on-disc tester. It turned out, that friction was – besides other parameters – dependent on determination
method and load. Friction determined at areal DLC/DLC contact zones was generally much higher (μDLC 0.1) than diamond tip versus DLC (∼μ
DLC
0.06).
Received: 19 June 2001/Accepted: 15 September 2001 相似文献
17.
Quasi-static and cyclic testing of specimens with high aspect ratios produced by micro-casting and micro-powder-injection-moulding 总被引:3,自引:0,他引:3
The presented investigations of material properties of micro-components have been carried out in one project of the DFG Collaborative
Research Centre (SFB) 499 “Development, production and quality assurance of moulded micro-components made out of metallic
and ceramic materials” [SFB01]. The aim of this SFB is to develop production methods for micro-components in large-, middle
and short-batches, where the applied metallic and ceramic materials can sustain high stresses and are wear-resistant, e.g.
in relation to plastics. A micro-turbine and a sun-and-planet gearing with three stages (outside diameter: 1.9 mm; already
realised in plastic [THü99]) are planned as a demonstration device. However, for the design of such micro-components, no reliable
data for material states in small dimensions are available. Therefore, bending-specimens made out of micro-cast Stabilor G
and out of micro-powder-injection-moulded ZrO2 were investigated with respect to their behaviour under quasi-static as well as under cyclic loading.
Received: 10 August 2001/Accepted: 24 September 2001 相似文献
18.
In ultraviolet (UV) embossing, a substrate with a coating of liquid or semi-solid UV curable resin mix is pressed against a patterned embossing mold. The resin mix is irradiated with UV before demolding of the hardened microstructures. UV embossing can be done at room temperature and low pressure. However, demolding of UV embossed high aspect ratio microstructures from a metallic mold is typically difficult since there is no differential thermal contraction between the mold and the embossing. Several factors have been identified to influence demolding of UV embossed microstructures: (1) Roughness of mold, (2) Taper angle of microstructures of mold, (3) Chemical interaction between mold and embossing, (4) Tensile and crosslinking shrinkage properties of the irradiated resin and (5) Uniformity of crosslinking process through the thickness of the molded microstructures. By controlling these five parameters, a microarray with an aspect ratio of 5 was demonstrated using a Formulation containing epoxy acrylate, Irgacure® 651, silicone acrylate and other acrylates. The embossed microstructures replicated the features of the mold very well. It was also shown that by controlling the amount of irradiation, the tensile modulus of the UV formulation increased whilst the elongation decreased. An optimum irradiation is needed for clean demolding from the mold without microcracking.This research was supported by a Strategic Development Scheme fund (SDS 15/2001) from the Nanyang Technological University. The authors also acknowledge the kind contributions of chemicals by UCB Chemicals, Sartomer, Henkel (Singapore), Dupont (Singapore) and Ciba Chemicals and a microstructured mold by Dr R. C. Liang of SiPix Imaging (CA, USA). The second author acknowledges the financial support of Nanyang Technological University through a Research Scholarship. 相似文献
19.
The developed process of tape casting with subsequent stamping is a promising way to make three-dimensional ceramic microstructures.
Examples of different ceramic materials illustrate, that a good quality of the moulding with high form fit can be attained
after optimisation of the slurry and the stamping process. The sintered microstructures are characterised by lateral dimensions
in the micron range and high aspect ratios. The unique properties of ceramic materials in combination with this new process
can be used to produce microstructured ultrasonic transducers or micro heat exchangers/reactors.
Received: 30 October 1995 / Accepted: 12 January 1996 相似文献
20.
A 3D electroplating process by means of pixel-wise, step height control of selective electroplating has been successfully
demonstrated. A total of eight rectangular pixels of 80 × 20 μm2 in area and 1.1–9.3 μm in height have been fabricated with a height difference of 1 μm in adjacent pixels. The process requires
only two masks in a single electroplating process. Nickel electroplating is selected as the demonstrating material and is
performed at 50 °C with current density of 400 A/m2 for 30 min. A theoretical model in electroplating process is discussed to assist the design of 3D microstructures and verified
with the experimental data. As such, this process has potential applications in making pixel-wise, 3D microstructures with
precise height control.
Received: 10 August 2001/Accepted: 24 September 2001 相似文献