• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 1999년도 추계종합학술대회 논문집
• /
• pp.203-207
• /
• 1999

In this paper we report new integration technology developed for three-dimensional metallic microstructures in an arbitrary shape. We have developed the two fabrication methods: Multi-Exposure and Single-Development (MESD) and Sacrificial Metallic Mold(SMM) techniques. Three-dimensional photoresist mold can be formed by the MESD method while unlimited number of structural levels can be realized by the SMM technique. Using these two techniques we have fabricated solenoid inductors and levitated spiral inductors for RF applications. We have achieved peak Q- factors over 40 in the 2-10㎓ range, the highest number among the inductors reported to date. Finally, we propose "On-Chip Passives" as a post IC process for monolithic integration of inductors, tunable capacitors, microwave switches, transmission lines, and mixers and filters toward future single-chip transceiver integration.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2006년도 춘계학술대회 논문집
• /
• pp.157-158
• /
• 2006

A novel nanofabrication process has been developed using two-photon crosslinking (TPC) for the fabrication of three-dimensional (3D) SiCN ceramic microstructures applicable to high functional 3D devices, which can be used in harsh working environments requiring a high temperature, a resistance to chemical corrosion, as well as tribological properties. After sequential processes: TPC and pyrolysis, 3D ceramic microstructures are obtained. However, large shrinkage due to low-ceramic yield during the pyrolysis is a serious problem to be solved in the precise fabrication of 3D ceramic microstructures. In this work, silica nanoparticles were employed as a filler to reduce the amount of shrinkage. In particular, the ceramic microstructures containing 40 wt% silica nanoparticles exhibited relatively isotropic shrinkage owing to its sliding free from the substrate during pyrolysis.

• 한국정밀공학회지
• /
• 제21권7호
• /
• pp.30-36
• /
• 2004

Recently, the lead-time of a product is to be shortened in order to satisfy consumer's demand. It is thus important to reduce the manufacturing time and the cost of 3D-shaped microstructures. Micro-Electro-Mechanical Systems (MEMS) and devices are usually fabricated by lithography-based methods. Above method is not flexible for the rapid manufacture of 3D-shaped microstructures because it depends on work's experiences and requires excessive cost and time for making many masks. In this paper, the effective laser micrornachining is developed to fabricate UV sensitive polymer microstructures using laser ablation. The proposed process, named by laser microRP, is a very useful method on rapid manufacturing for 3D-shaped microstructures.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2007년도 춘계학술대회A
• /
• pp.1259-1264
• /
• 2007

Microstereolithography technology has potential capability for fabrication of 3D microstructures. It evolved from conventional SLA which is one of the RP processes. In a microstereolithography process, 3D microstructures can be easily fabricated by continuously stacking 2D layer which is photopolymerized using a liquid prepolymer. Combination between biocompatible/biodegradable photocurable prepolymer and 3D complex fabrication in microstereolithography makes broad application areas such as medical, pharmaceutic, and bio devices. In particular, a 3D microneedle for transdermal drug delivery and a scaffold for tissue engineering are fabricated using this technology. In this paper, the authors address development of microstereolithography system adapted to large surface and fabrication of various microstructures. In addition, to apply human body we suggest a biodegradable 3D microneedle and a scaffold using biodegradable photocurable prepolymer.

• 한국정밀공학회지
• /
• 제26권8호
• /
• pp.119-125
• /
• 2009

Fabrication of a three-dimensional (3D) metallic mold for multi-production of a microstructure was studied to settle the problem of long processing time in 3D microfabrication. To date, complicated 3D microstructures including 3D photonic crystals, 3D microlens array, 3D filter for microfludics, and something else were created successfully using the two-photon polymerization (TPP) which was considered as paving the way to fabricate a real 3D shape in nano/microscale. However, for those fabrications, much processing time and efforts were inevitably required. To solve this issue, a simple and effective way was proposed in this paper; 3D master patterns were prepared using TPP, and then counter-shaped Ni molds were fabricated by electroforming process. By using these molds, 3D microstructures can be reproduced with short-processing time and low-effort comparing to the conventional approach, TPP We report some parameters to fabricate a metallic mold precisely.

• 한국정밀공학회지
• /
• 제23권11호
• /
• pp.116-125
• /
• 2006

MEMS and LIGA technologies have been used for fabricating microstructures, but their shape is not 3D because of difficulty for preparation of many masks. To fabricate 3D microstructures, microstereolithography technology based on Digital Micromirror Device($DMD^{TM}$) was introduced. It has no need of masks and is capable of fabricating high aspect ratio microstructures. In this technology, STL file is the standard format as the same of conventional rapid prototyping system, and 3D parts are fabricated by layer-by-layer according to 2D section sliced from STL file. The UV light source is illuminated to DMD which makes bitmap images of 2D section, and they are transferred and focused on resin surface. In this paper, we addressed optical design of microstereolithography system in consideration of light path according to DMD operation and image-forming on the resin surface using optical design program. To verify the performance of implemented microstereolithography system, 3D microstructures with complexity and high aspect ratio were fabricated.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제2권4호
• /
• pp.268-272
• /
• 2002

This paper presents a novel microfabrication technology of 3D microstructures with inclined/rotated UV lithography using negative photoresist, SU-8. In some cases, reflected UV as well as incident UV is used to form microstructures. Various 3D microstructures are simply fabricated such as embedded channels, bridges, V-grooves, truncated cones, and so on.

• 한국정밀공학회지
• /
• 제24권12호
• /
• pp.136-142
• /
• 2007

Precise fabrication of three-dimensional (3D) self-standing microstructures on thin glass plates via two-photon induced polymerization (TPP) has been an important issue for innovative 3D nanodevices and microdevices. However, there are still issues remaining to be solved, such as building 3D microstructures on opaque materials via TPP and being able to implant them as functional parts onto practical systems. To settle these issues simply and effectively, we propose a contact print lithography (CPL) method using an ultraviolet (UV)-curable polymer layer. We report some of the possibilities and potential of CPL by presenting our results for transplanting 3D microstructures onto large-area substrates and also our examination of some of the effects of the process parameters on successful transplantation.

• 대한기계학회논문집A
• /
• 제40권8호
• /
• pp.731-736
• /
• 2016

본 연구에서는 의용생체공학에 널리 사용되는 미소바늘과 같은 3차원 고종횡비 미소구조물을 용이하게 제작할 수 있는 하이브리드 자외선 노광법에 대해 기술한다. 하이브리드 자외선 노광법은 기존에 사용되고 있는 경사노광, 회전노광 및 역노광을 혼합한 방법으로, 경사 및 회전노광은 경사진 축대칭 형상을 가지는 3차원 미소구조물의 제작이 가능하도록 하고 역노광은 자외선 노광공정 중 필연적으로 발생하는 하부기판에서의 자외선 반사를 최소화 시킨다. 자체 개발한 자외선 노광시스템과 SU-8 음성감광제를 이용하여 하이브리드 자외선 노광법의 다양한 공정조건이 최종 제작된 3차원 고종횡비 미소구조물 형상(종횡비, 선단의 곡률반경 등)에 미치는 효과를 확인한다. 또한 SU-8의 소프트 베이킹(soft baking) 조건과 미소구조물 선단 형상 사이의 관계에 대해서도 논의한다.

• 한국정밀공학회지
• /
• 제25권1호
• /
• pp.122-129
• /
• 2008

Two-photon stereolithography is recognized as a promising process for the fabrication of three-dimensional (3D) microstructures with 100 nm resolution. Generally, beam-scanning system has been used in the conventional process of two-photon stereolithography, which is limited to the fabrication of micro-prototypes in small area of several tens micrometers. For the applications to 3D high-functional micro-devices, the fabrication area of the process is required to be enlarged. In this paper, large-area two-photon stereolithography (L-TPS) employing stage scanning system has been developed. Continuous scanning method is suggested to improve the fabrication speed and parameter study is conducted. An objective lens of high numerical aperture (N.A.) and high strength material were employed in this system. Through this work, 3D microstructures of $600*600*100\;{\mu}m$ were fabricated.