Laminated Photoresist Sacrificial Layer Process for 3-D Movable Suspension Microstructures in LIGA-Based Surface Micromachining

2010 ◽  
Vol 97-101 ◽  
pp. 2538-2541 ◽  
Author(s):  
Yi Bo Wu ◽  
Gui Fu Ding ◽  
Cong Chun Zhang ◽  
Hong Wang
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Sacrificial Layer ◽  
Low Cost ◽  
Three Dimensional ◽  
Mems Devices ◽  
Metal Structures ◽  
Positive Photoresist ◽  
Out Of Plane ◽  
Freely Moving

The fabrication process of three-dimensional (3D) high-aspect-ratio MEMS devices entirely made of electroplated metals with suspending multilayered microstructures is reported. The technology used is a LIGA-liked micromachining process, called the laminated positive photoresist sacrificial layer process (LPSLP). The LPSLP allows in UV-lithography not only for thick resist mould for electroplating of cascaded metal structures but also for the sacrificial layer for supporting mechanically the suspensions. So far the LPSLP procedure has incorporated with more than five sacrificial layers, which allows for the creation of overhanging structures and freely moving parts like out-of-plane cantilever stacks. A description of the underlying fabrication principle and processing details is discussed in this paper. Thus the proposed procedures open a low-cost route for fabricating micro-components such as cantilevers, bridges, movable electrodes, and freestanding parts.

Development of LIGA-Like Process With Positive Photoresist and SU-8

2010 ◽  
Author(s):  
Yongsu Lee ◽  
Jinha Kim ◽  
Seokwoo Lee ◽  
Seungsub Lee
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Spin Coating ◽  
Atmospheric Condition ◽  
Metal Structures ◽  
Positive Photoresist ◽  
Dry Process ◽  
Aspect Ratios ◽  
Thick Photoresist ◽  
Photolithography Process

LIGA-Like techniques allows the fabrication of structures with high aspect ratio. SU-8 is a well-known thick photoresist used in this process. However, the remainder of highly cross-linked epoxy after photolithography process is difficult to remove without damage or alteration to electroplated metal due to the high aspect ratio of the structure. Different from SU-8, positive photoresist is easily removed, yet has limitation of fabricating structures with high aspect ratio. In this paper, we present novel LIGA-Like process with positive photoresist to improve above mentioned difficulties. In order to increase a height of positive photoresist, we have introduced SU-8 into the system. SU-8 is used for cast to control the thickness of positive photoresist, and AZ9260 (positive photoresis) is used for electroplating mold. In this suggested process, Donut-shaped SU-8 cast is patterned on the border of substrate to control and increase total height of positive photoresist. AZ9260, a kind of positive photoresist, fills the center of vacant area, and the thickness of the AZ9260 is controlled by height of SU-8 cast during the process of slow spin coating. After spin coating, the system is exposed to natural atmospheric condition for hours to improve surface planarization. The soft baking is carried out in two steps. The purpose of first prebaking is to evaporate large amount of solvent, and second prebaking is to enhance aspect ratios of photoresist. In the process of prebaking, the AZ9260 coated wafer is covered with chalet due to the fast dry process causes wrinkle and bubble on the surface. Through extensive experiments, we have established the condition of spin coating, exposure doses, prebaking and development process in each structure of 150, 200 and 240 μm thickness. Different from the case of SU-8, AZ9260 mold can be effectively removed after electroplating treatment. Finally, we obtain metal structures of 150, 200, 240μm heights corresponding to the mold height (AZ9260). It is shown that SU-8 can be successfully replaced by positive photoresist in LIGA-Like process. Therefore, the suggested fabrication method can be applied to materialize the positive photoresist structures with high aspect ratio in UV lithography process.

A Novel Embedded Root Method to Construct Thick Metal Microstructures Using SU-8 in UV-LIGA Process

2002 ◽  
Author(s):  
Chien-Hung Ho ◽  
Kan-Ping Chin
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Electrostatic Force ◽  
Low Cost ◽  
Three Dimensional ◽  
Mechanical Systems ◽  
Improved Method ◽  
Micro Electro Mechanical Systems ◽  
Novel Technique

To upgrade the electrostatic force, movable devices in micro-electro-mechanical systems may require three-dimensional microstructures with large capacitive areas and vertical sidewalls with several hundred micrometers in height. The photoresist, NANO™ XP SU–8, can be implemented in the fabrication of high-aspect-ratio microstructures in low-cost MEMS production. In this study, using SU-8 as an electroplating mold, an improved method for consolidating the adhesion of the plated microstructures to the substrate is utilized. By constructing an embedded root as the substructure, this novel technique can greatly increase the thickness of the metal components, and simultaneously, the hard-to-strip crosslinked SU-8 may be removed completely. The fabrication of stators and bearing post for an electrostatic micro motor is used here to demonstrate the effectiveness of the proposed method, where the structural height and the minimum gap of the stators are 300 μm and 50 μm, respectively. For comparison, some fabricated results of typical approaches by a heated remover to strip the cured SU-8 mold are also shown in this paper.

Accelerating ion diffusion with unique three-dimensionally interconnected nanopores for self-membrane high-performance pseudocapacitors

Nanoscale ◽  
2017 ◽  
Vol 9 (46) ◽  
pp. 18311-18317 ◽  
Author(s):  
Yuan Gao ◽  
Yuanjing Lin ◽  
Zehua Peng ◽  
Qingfeng Zhou ◽  
Zhiyong Fan
Keyword(s):  
Aspect Ratio ◽  
Surface Area ◽  
Structural Stability ◽  
High Aspect Ratio ◽  
High Performance ◽  
Three Dimensional ◽  
Rate Capability ◽  
Large Surface Area ◽  
Nanoporous Structure ◽  
Ion Diffusion

Three-dimensional interconnected nanoporous structure (3-D INPOS) possesses high aspect ratio, large surface area, as well as good structural stability. Profiting from its unique interconnected architecture, the 3-D INPOS pseudocapacitor achieves a largely enhanced capacitance and rate capability.

scholarly journals Self-ordered nanospike porous alumina fabricated under a new regime by an anodizing process in alkaline media

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mana Iwai ◽  
Tatsuya Kikuchi ◽  
Ryosuke O. Suzuki
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Porous Alumina ◽  
Three Dimensional ◽  
Alkaline Media ◽  
Alkaline Electrolyte ◽  
Subsequent Formation ◽  
Interpore Distance ◽  
Wide Range ◽  
Ordered Porous

AbstractHigh-aspect ratio ordered nanomaterial arrays exhibit several unique physicochemical and optical properties. Porous anodic aluminum oxide (AAO) is one of the most typical ordered porous structures and can be easily fabricated by applying an electrochemical anodizing process to Al. However, the dimensional and structural controllability of conventional porous AAOs is limited to a narrow range because there are only a few electrolytes that work in this process. Here, we provide a novel anodizing method using an alkaline electrolyte, sodium tetraborate (Na2B4O7), for the fabrication of a high-aspect ratio, self-ordered nanospike porous AAO structure. This self-ordered porous AAO structure possesses a wide range of the interpore distance under a new anodizing regime, and highly ordered porous AAO structures can be fabricated using pre-nanotexturing of Al. The vertical pore walls of porous AAOs have unique nanospikes measuring several tens of nanometers in periodicity, and we demonstrate that AAO can be used as a template for the fabrication of nanomaterials with a large surface area. We also reveal that stable anodizing without the occurrence of oxide burning and the subsequent formation of uniform self-ordered AAO structures can be achieved on complicated three-dimensional substrates.

Stiffened Hangers: an Often Overlooked Tool for Conceptual Design of Tied-Arch Footbridges

2021 ◽  
Author(s):  
Juan José Jorquera-Lucerga ◽  
Juan Manuel GARCÍA-GUERRERO
Keyword(s):  
Low Cost ◽  
Three Dimensional ◽  
Structural Response ◽  
Bending Moments ◽  
Structural Element ◽  
Axial Forces ◽  
Limited Effectiveness ◽  
Out Of Plane ◽  
Arch Bridges ◽  
Fixed End

<p>In tied-arch bridges, the way the arch and the deck are connected may become crucial. The deck is usually suspended from hangers made out of steel pinned cables capable of resisting axial forces only. However, a proper structural response, (both in-plane and out-of-plane) may be ensured by fixing and stiffening the hangers in order to resist, additionally, shear forces and bending moments. This paper studies the effect of different pinned and stiffened hanger arrangements on the structural behavior of the tied-arch footbridges, with the intention of providing designers with useful tools at the early steps of design. As a major conclusion, regarding the in-plane behavior, hangers composed of cables (either with vertical, Nielsen-Löhse or network arrangements) are recommended due to its low cost and ease of erection. Alternatively, longitudinally stiffened hangers, fixed at both ends, can be used. Regarding the out-of-plane behavior, and in addition to three-dimensional arrangements of cables, of limited effectiveness, transversally stiffened hangers fixed at both ends are the most efficient arrangement. A configuration almost as efficient can be achieved by locating a hinge at the end corresponding to the most flexible structural element (normally the arch). Its efficiency is further improved if the cross-section tapers from the fixed end to the pinned end.</p>

EFAB: High Aspect Ratio, Arbitrary 3-D Metal Microstructures Using a Low-Cost Automated Batch Process

1999 ◽  
Author(s):  
Fan-Gang Tseng ◽  
Gang Zhang ◽  
Uri Frodis ◽  
Adam Cohen ◽  
Florian Mansfeld ◽  
...  
Keyword(s):  
Low Temperature ◽  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Low Cost ◽  
Batch Process ◽  
Unlimited Number ◽  
Metal Layers ◽  
Electrochemical Fabrication ◽  
Low Temperature Process

Abstract EFAB (“Electrochemical FABrication”) is a new micromachining process utilizing an innovative “Instant Masking” (IM) technique to electrochemically deposit an unlimited number of metal layers for microfabrication. Through this approach, high-aspect-ratio microstructures with arbitrary 3-D geometry can be rapidly and automatically batch-fabricated at low temperature (&lt; 60 °C) using an inexpensive desktop machine. IC-MEMS integration can also be carried out by this low temperature process.

Technology chain for production of low-cost high aspect ratio optical structures

2007 ◽  
pp. 658-662
Author(s):  
R. Krajewski ◽  
J. Krezel ◽  
M. Kujawinska ◽  
O. Parriaux ◽  
S. Tonchev ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Low Cost
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