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A cell culture on a scaffold has the advantages of functionality and easy handling, because the geometry of the cellular tissue is controlled by designing the scaffold. To create complex cellular tissue, scaffolds should be complex two-dimensional (2D) and three-dimensional (3D) structures. However, it is difficult to fabricate a scaffold with a 2D and 3D structure because the shape, size, and fabrication processes of a 2D structure in creating a cell layer, and a 3D structure containing cells, are different. In this research, we propose a micropatterning method for porous materials using the difference of the glass transition temperature between exposed and unexposed areas of a thick-photoresist. Since the proposed method does not require a vacuum, high temperature, or high voltage, it can be used for fabricating various structures with a wide range of scales, regardless of the materials used. Additionally, the patterning area can be fabricated accurately by photolithography. To evaluate the proposed method, a membrane integrated scaffold (MIS) with a 2D porous membrane and 3D porous material was fabricated. The MIS had a porous membrane with a pore size of 4 &mu, m or less, which was impermeable to cells, and a porous material which was capable of containing cells. By seeding HUVECs and HeLa cells on each side of the MIS, the cellular tissue was formed with the designed geometry.

This paper presents a fabrication of extremely thick SU-8 photoresist process in a height range Of $\mathbf{1000}\ \mu \mathbf{m}$ to $\mathbf{2000}\ \mu \mathbf{m}$ high-aspect-ratio microstructures. To differentiate conventional high-aspect-ratio tall structures less than $\mathbf{1000}\ \mu \mathbf{m}$, a new term, microtower, was adopted for the microstructure with a height of $\mathbf{1000}\ \mu \mathbf{m}$ or taller. In fabrication process, to avoid a long softbaking process from the thick photoresist and provide uniform film thickness, an SU-8 dry film was adopted. Ultra-violet (UV) light exposure with an acrylic filter was investigated in terms of transparency of the applicable wavelength spectrum. An array of the $\mathbf{1000}-\mu \mathbf{m}$ tall microtower array was fabricated without the acrylic filter resulting in wavy sidewalls. Whereas an array of $\mathbf{2000}-\mu \mathbf{m}$ tall microtower was fabricated with the acrylic filter resulting straight sidewalls. An array of $\mathbf{1500}-\mu \mathbf{m}$ -long inclined V-pillars was also successfully fabricated by adopting the UV exposure with the acrylic filter, and the fabricated microstructures have potential use as a microfilter in microfluidics. A state-of-art 100-turn toroid inductor was successfully fabricated and electrically characterized resulting an average inductance of 950 nH in the frequency range of 0.1 to 10 MHz. A low-frequency resistance of $\mathbf{5.4}\ \Omega$ at 0.1 MHz and a quality factor of 22 at 60 MHz were measured.

A major breakthrough in UV-LIGA (Lithographie, Galvanoformung and Abformung) started with the use of epoxy-based EPON® SU-8 photoresist in the mid-1990s. Using this photoresist has enabled the fabrication of tall and high aspect ratio structures without the use of a very expensive synchrotron source needed to expose the photoresist layer in X-ray LIGA. SU-8 photoresist appeared to be well-suited for LIGA templates, but also as a permanent material. Based on UV-LIGA and SU-8, Mimotec SA has developed processes to manufacture mold inserts and metallic components for various market fields. From one to three-level parts, from Ni to other materials, from simple to complicated parts with integrated functionalities, UV-LIGA has established itself as a manufacturing technology of importance for prototyping, as well as for mass-fabrication. This paper reviews some of the developments that led to commercial success in this field.

In this work, the design and fabrication of a low f-number cylindrical microlens array is presented. The lenses were fabricated in thick photo resist of 12 μm thickness, using a contact printer exposure through a mask with a repetitive 6 μm line - 4 μm space pattern. Numerical calculations based on scalar diffraction theory were employed to model the light propagation inside the resist, determining the aerial image as a function of its thickness. Than the resist response characteristics, expressed by its contrast curve, and absorption rate were used to obtain a cross section profile. A good match between numerical and experimental results were found.

Fabrication of tall features using selective electrodeposition is well known process and has several applications in microelectronics packaging. The use of conventional exposure and development processes is limited by the aspect ratio and sizes of the features obtained. This paper describes a novel approach to fabricated tall structures featured in thick photoresist . Tin and copper tall structures were made by selective electrodeposition. Also presented are results from experiments performed to fabricate tall tin and copper pillars with nearly vertical walls on bare dices to form interconnect.

本研究は, UV厚膜レジストによるフォトリソグラフィと電鋳の組み合わせによりマイクロコネクタを作製し, その特性評価を行った。作製したマイクロコネクタは100ピンで, 厚さ50μm, 最小幅15μm, 最大アスペクト比3.3であり, 端子間のピッチは80μmである。特性評価として接触力, 接触抵抗, ヤング率, 許容電流値の測定を行った。ソケット端子の変位量が5μmのときの接触力は3.3mNであった。四探針法により測定した端子間の接触抵抗は50mΩ以下であった。SPM法などにより端子を構成するNi構造体のヤング率を測定したところ180GPaであった。また, 環境試験を実施した結果, 設計したマイクロコネクタはAuめっきを施すことで安定した電気的接触が得られる見通しを得た。

A new low-cost UV LIGA process using photoresists as sacrificial layers has been developed to fabricate micromechanical components and systems. Commonly used photoresists are spun on a substrate and patterned by a mask aligner. Free-standing metal structures are built by patterning a second layer of thick photoresist and electroplating upon the photoresist sacrificial layer. Compared with all the existing sacrificial layer techniques, photoresists are easy to coat, easy to dissolve and fewer process steps are involved. The process is compatible to most of the materials and processes used in existing microfabrication technology. The precision issue of UV LIGA technique is also discussed.

In this study, a novel packaging structure for open-channel sensor was successfully demonstrated by using the sacrifice-replacement method. This method was patterned JSR THB-151N photoresist to fabricate an open space to contact medium. The sacrificial-barriers of 75 and 150 mum thickness have been fabricated with good reproducibility by using single and double coating processes. Optimized fabrication parameters were achieved straight and nearly vertical sidewall profiles. In addition, after the encapsulation process, JSR photoresist has been stripped clearly and easily without residues in stripper solutions. Finally, the sensing channel was reserved in packaging body resulting from sacrifice-replacement approach.

The present study provides a novel carrier fabrication method for biomedical application. The SU-8 thick photoresist fabrication process is used to produce the /spl mu/-carrier of 200 /spl mu/m/spl times/200 /spl mu/m with various thicknesses. These /spl mu/-carriers will be used for the purpose of biomedical inspection after proper surface modification by chemicals. To quantify and qualify the immersed /spl mu/-carriers in the inspected solution, specific marker is designed and fabricated on every /spl mu/-carrier as identification according to the application. Hence, a precise control on the marker feature dimension will be crucial for the application. In addition, the thick resist layer uniformity is very important in defining the marker pattern on the surface of carrier. Besides, the sidewall profile is also crucial especially for the fabrication of 10 /spl mu/m through-hole markers on the carriers of 50 /spl mu/m to 100 /spl mu/m thick. The orthogonal array experimental design method is employed to optimize the process parameters, including the soft bake, exposure, postexposure bake, and development parameters. Moreover, the effect of development with ultrasonic agitation is also investigated.

Interest in thick photoresist applications is steadily growing. Specialised equipment has been developed to cope with the new challenges in the field of preparing extremely thick photoresist layers and the process to pattern these thick resists. A new technology called 3D UV-Microforming consisting of an advanced resist preparation process, UV lithographic steps, resist development, moulding procedures by electrodeposition, and finally stripping and cleaning for finishing the structures was developed. It enables the low-cost fabrication of a wide variety of micro components for many different users.

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).

The fabrication of photoresist gratings is considered. A solution to the problem of ‘transversal standing waves’ is given and appears simple and versatile.

In this paper, we describe a culture-based biochip for detecting microorganisms in environmental samples in an improved, timesaving, and cost-efficient manner. The biochips use the paraffinophilic nature of microorganisms to rapidly detect and differentiate them in sewage samples collected from wastewater treatment plants. A new method of depositing paraffin was developed to fabricate the biochips. The developed technique uses butanol solvent to keep paraffin liquid during spin-coating and thick photoresist for patterning. Using this approach, paraffin layers of 5-70 /spl mu/m have been successfully fabricated and patterned. These biochips were used to demonstrate rapid, 5-min detection of microorganisms responsible for reactor foaming in wastewater treatment.