• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1991-1993
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• 2002

This paper presents the PDMS surface characteristic change after the plasma process and the electroosmotic flow control technique for the two-dimensional focusing in the micro channels made of PDMS and glass. The channels are fabricated by plastic molding and micromachining technique. To observe the surface characteristic change as time elapses, we measure the contact angle of water on the surface and the velocity of the electroosmotic flow in a channel. The electric field adequate for focusing of a core flow in a confluence channel is obtained by the experiment. The computer simulation is performed to obtain the width and the depth of the core flow for several junction angles of the confluence channel.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권8호
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• pp.487-494
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• 2000

This paper describes the design, fabrication and experiments of surface-micromachined aluminum micromirror array with hidden pin-joints. Instead of the conventional elastic spring components as connection between mirror plate and supporting structure, we used pin-joint composed of pin and staples to support the mirror plate. The placement of pin-joint under the mirror plate makes large active surface area possible. These flexureless micromirrors are driven by electrostatic force. As the mirror plate has discrete deflection angles, the device can be ap;lied to adaptive optics and digitally-operating optical applications. Four-level metal structural layers and semi-cured photoresist sacrificial layers were used in the fabrication process and sacrificial layers were removed by oxygen plasma ashing. Static characteristics of fabricated samples were measured and compared with modeling results.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 춘계학술대회 논문집
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• pp.47-50
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• 2005

In this study, micro mirror array for small form factor optical pick-up was replicated by micro UV-molding. First, mold for micro mirror array was fabricated using micromachining. Also, to analyze the characteristics of the surface quality, flatness of replicated mirror surface were measured by white light scanning inteferometry system. The results show that the micro mirror array with a sufficient surface quality can be obtained by polymer replication process.

• 한국항공우주학회지
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• 제31권2호
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• pp.57-62
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• 2003

MEMS(미소전기기계시스템) 박막의 푸와송비 측정을 위한 미소굽힙기법이 제안되었다. 푸와송비 측정에 민감한 쌍원시편(두 개의 원모양)을 설계하고 표면미세가공 공정을 사용하여 제작하였다. 미소압입기로 하중을 가한 쌍원시편의 하중-변위 곡선을 분석하여 푸와송비를 측정할 수 있었다. 제안도니 미소굽힘기법은 표면미세가공에 적합하여 소자제작과정에서의 동시측정이 가능하고(in-situ measurement), 소자가 위치해 있는 작은 영영에서의 물성을 국부적으로 측정할 수 있는 장점이 있다. 제안된 기법을 검증하기 위하여 저압화학기상증착법에 의하여 증착된 2.3㎛ 다결정실리콘(Poly-silicon)의 푸와송비를 측정하였다. 실험에 사용된 다결정실리콘막의 푸와송비는 0.2569 이고 쌍원시편의 강성에 대한 측정표준편차는 2.66% 이었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.246-250
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• 2003

In this study, two new types of micro-grippers in which micro-fingers are actuated by piezoelectric multi-layer benders and stacks are introduced for the manipulation of micrometer-sized objects. First, we constructed a 3-chopstick-mechanism tungsten gripper, which is composed of three chopsticks: two are designed to grip micro-objects, and tile third is used to help grasp and release the objects through overcoming especially electrostatic force among some surface effects including electrostatic, van der Waals forces and surface tension. Second, a 2-chopstick-mechanism silicon micro-gripper that uses an integrated force sensor to control the gripping force was developed. The micro-gripper is composed of a piezoelectric multilayer bender for actuating the gripper fingers, silicon fingertips fabricated by use of silicon-based micromachining, and supplementary supports. The micro-gripper is referred to as a hybrid-type micro-gripper because it is composed of two main components; micro-fingertips fabricated using micromachining technology to integrate a very sensitive force sensor for measuring the gripping force, and piezoelectric gripper finger actuators that are capable of large gripping forces and moving strokes. The gripping force signal was found to have a sensitivity of 667 N/V. To the design of each of components of both of the grippers. a systematic design approach was applied, which made it possible to establish the functional requirements and design parameters of the micro-grippers. The micro-grippers were installed on a manual manipulator to assess its performance in tasks such as moving micro-objects from one position to a desired position. The experiment showed that the micro-grippers function effectively.

• 한국기계가공학회지
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• 제6권1호
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• pp.34-42
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• 2007

Powder blasting technique has been considered one of the most appropriate micro machining methods for hard and brittle materials, since the productivity is high and the heat layers caused by material removal are very thin. Recent development of special purposed parts, such as the parts for semiconductor processing, the parts for LCD, sensors for micro machine fabrication and so on, has been expanded. Thus, it is essential to develop powder blasting technologies for micromachining of hard and brittle materials such as glass, ceramics and so on. In this paper, the characteristics of powder blasted glass surface were tested under various blasting parameters. Finally, we proposed a predictive model for powder blasting process using the neural network and the response surface method. Detail analysis of the simulation results is carried out and the performance of two predictive models is compared.

• Journal of Electrical Engineering and Technology
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• 제3권2호
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• pp.271-275
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• 2008

The MAM(Megasonic Agitated Module) has been fabricated for improving the characteristics of wet etching. The characteristics of the MAM are investigated during the wet etching with and without megasonic agitation in this paper. The adoption of the MAM has improved the characteristics of wet etching, such as the etch rate, etch uniformity, and surface roughness. Especially, the etching uniformity on the entire wafer was less than ${\pm}1%$ in both cases of Si and glass. Generally, the initial root-mean-square roughness($R_{rms}$) of the single crystal silicon was 0.23nm. Roughnesses of 566nm and 66nm have been achieved with magnetic stirring and ultrasonic agitation, respectively, by some researchers. In this paper, the roughness of the etched Si surface is less than 60 nm. Wet etching of silicon with megasonic agitation can maintain nearly the original surface roughness during etching. The results verified that megasonic agitation is an effective way to improve etching characteristics of the etch rate, etch uniformity, and surface roughness and that the developed micromachining system is suitable for the fabrication of devices with complex structures.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제50권7호
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• pp.346-350
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• 2001

We present a surface-micromachined polysilicon capacitive accelerometer using unevenly distributed comb electrodes. The unique features of the accelerometer include a perforated proof-mass and the inner and outer comb electrodes with uneven electrode gaps. The perforated proof-mass reduces stiction between the structure and the substrate and the unevenly distributed electrodes shorten the electrode length required for a given sensitivity. The polysilicon accelerometer has been fabricated by the conventional 6-mask surface-micromachining process and showes a sensitivity of 1.03mV/g with a hybrid detection circuitry.

• 한국반도체및디스플레이장비학회:학술대회논문집
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• 한국반도체및디스플레이장비학회 2006년도 춘계학술대회
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• pp.251-254
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• 2006

In this paper, cutting qualifies and fracture strength of silicon dies by laser dicing are investigated. Laser micromachining is the non-contact process using thermal ablation and evaporation mechanisms. By these mechanisms, debris is generated and stick on the surface of wafer, which is the problem to apply laser dicing to semiconductor manufacture process. Unlike mechanical sawing using diamond blade, chipping on the surface and crack on the back side of wafer isn't made by laser dicing. Die strength by laser dicing is measured via the three-point bending test and is compared with the die strength by mechanical sawing. As a results, die strength by the laser dicing shows a decrease of 50% in compared with die strength by the mechanical sawing.

• 한국전기전자재료학회논문지
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• 제11권8호
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• pp.620-627
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• 1998

For chemical microsensors such as humidity and gas sensors, it is essential to obtain a single pore with a large inner surface and straight structure. In this paper, cylindrical macroporous silicon layers have been formed of p-silicon substrate by anodization in HF-ethanol-water solution with an applied current. The pores grew normal to the (100) surface and were uniformly distributed. The pore diameter was approximately $1.5~2{\mu}m$ with a depth of $20~30{\mu}m$ and the pores were not interconnected, which are in sharp contrast to the porous silicon reported previouly for similarly doped p-Si. Porous silicon diaphragms 18 to $200{\mu}m$ thick were formed by anistropic etching in TMAH solution and then anodization. The fabrication of macroporous silicon and free-standing diaphragms is expected to offer applications for microsensors, micromachining, and separators.