• ETRI Journal
• /
• 제27권4호
• /
• pp.433-438
• /
• 2005

We present a new type of silicon micro-probe card using a three-dimensional probe beam of the cantilever type. It was fabricated using KOH and dry etching, a porous silicon micromachining technique, and an Au electroplating process. The cantilever-type probe beam had a thickness of $5 {\mu}m$, and a width of $50{\mu}$ and a length of $800 {\mu}m$. The probe beam for pad contact was formed by the thermal expansion coefficient difference between the films. The maximum height of the curled probe beam was $170 {\mu}m$, and an annealing process was performed for 20 min at $500^{\circ}C$. The contact resistance of the newly fabricated probe card was less than $2{\Omega}$, and its lifetime was more than 20,000 turns.

• 한국전기전자재료학회논문지
• /
• 제22권4호
• /
• pp.314-317
• /
• 2009

This paper describes the temperature characteristics of polycrystalline 3C-SiC micro resonators. The $1.2{\mu}m$ and $0.4{\mu}m$ thick polycrystalline 3C-SiC cantilever and doubly clamped beam resonators with $60{\sim}100{\mu}m$ lengths were fabricated using a surface micromachining technique. Polycrystalline 3C-SiC micro resonators were actuated by piezoelectric element and their fundamental resonance was measured by a laser vibrometer in vacuum at temperature range of $25{\sim}200^{\circ}C$. The TCF(Temperature Coefficient of Frequency) of 60, 80 and 100 On long cantilever resonators were -9.79, -7.72 and -8.0 ppm/$^{\circ}C$. On the other hand, TCF of 60, 80 and $100{\mu}m$ long doubly clamped beam resonators were -15.74, -12.55 and -8.35 ppm/$^{\circ}C$. Therefore, polycrystalline 3C-SiC resonators are suitable with RF MEMS devices and bio/chemical sensor applications in harsh environments.

• 센서학회지
• /
• 제18권3호
• /
• pp.207-209
• /
• 2009

This paper describes the characteristics of poly 3C-SiC micro resonators with $3{\times}10^{17}{\sim}1{\times}10^{19}cm^{-3}$ doping concentrations. The 1.2 ${\mu}m$ thick cantilever and the 0.4 ${\mu}m$ thick doubly clamped beam resonators with different lengths were fabricated using poly 3C-SiC thin films. The characteristics of poly 3C-SiC micro resonators were evaluated by quartz and a laser vibrometer in vacuum at room temperature. The resonant frequencies of micro resonators decreased with doping concentrations owing to reduction in the Young's modulus of poly 3C-SiC thin films. It was confirmed that the resonant frequencies of poly 3C-SiC resonators are controllable by doping concentrations. Therefore, poly 3C-SiC resonators could be applied to MEMS devices and bio/chemical sensor applications.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
• /
• pp.412-413
• /
• 2005

This paper describes resonant frequency of the structural behavior of micro-cantilever beam simulated by FEM (Finite Element Method). The resonant characteristics and the sensitivity of cantilever-shaped SOI resonant were measured for the application of chemical sensor. The resonant frequency of the fabricated micro-cantilever system was found to be 5.59kHz when the size of cantilever is $500{\mu}m$ long, $100{\mu}m$ wide and $1{\mu}m$ thick. Generation of resonant frequency measured by Modal Analysis is resulted in length of cantilever. The length was found to be a dominant factor for the selection of required resonant frequency range. On the other side, the width had influenced very little on either the magnitude of resonant frequency or the sensitivity.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2009년도 추계학술대회 논문집
• /
• pp.130-130
• /
• 2009

This paper describes the temperature characteristics of polycrystalline 3C-SiC micro resonators. The 1.2 ${\mu}m$ and 0.4 ${\mu}m$ thick polycrystalline 3C-SiC cantilever and doubly clamped beam resonators with 60 ~ 100 ${\mu}m$ lengths were fabricated using a surface micromachining technique. Polycrystalline 3C-SiC micro resonators were actuated by piezoelectric element and their fundamental resonance was measured by a laser vibrometer in vacuum at temperature range of $25{\sim}200^{\circ}C$. The TCF(Temperature Coefficient of Frequency) of 60, 80 and 100 ${\mu}m$ long cantilever resonators were -9.79, -7.72 and -8.0 $ppm/^{\circ}C$. On the other hand, TCF of 60, 80 and 100 ${\mu}m$ long doubly clamped beam resonators were -15.74, -12.55 and -8.35 $ppm/^{\circ}C$. Therefore, polycrystalline 3C-SiC resonators are suitable with RF MEMS devices and bio/chemical sensor applications in harsh environments.

• 한국진공학회지
• /
• 제21권1호
• /
• pp.36-40
• /
• 2012

마이크로미터 크기의 역학적 공진기의 제작과 그 공진 주파수 변화를 이용하여 질량 변화량을 측정하는 방법에 대해 연구 하였다. 공진기의 공진 주파수를 측정하기 위해서 레이저의 간섭효과를 이용한 광학적 측정법을 사용하였는데 이 방법은 나노미터 스케일의 변위까지 감지할 수 있을 정도로 매우 감도가 높은 측정법이다. 공진기는 압전 세라믹(piezo ceramic) 위에 원자현미경(atomic force microscope)의 캔티레버를 붙여서 만들었는데 이 방법은 압전판이 캔티레버의 공진 주파수로 진동할 때 캔티레버의 변위가 가장 크게 변화됨을 이용한 것이다. 또한, 전자 빔 증착기(e-beam evaporation system)를 사용하여 금을 캔티레버 위에 증착하여 질량을 변화시킨 후에 질량 변화량에 따른 공진주파수의 변화량을 측정하였다. 이 공진기는 질량센서의 역할을 수행할 수 있으며 수 마이크로그램을 감지할 수 있는 감도를 가짐을 확인하였다.

• 대한기계학회논문집A
• /
• 제33권11호
• /
• pp.1314-1319
• /
• 2009

The design methods of mechanical systems are largely classified into deterministic methods and stochastic methods. In deterministic methods, design parameters are assumed to have fixed values. On the other hand, in stochastic methods, design parameters are assumed to be statistically distributed. When a stochastic method is employed, statistical characteristics of the populations of design variables are assumed to be known. However, very often, it is almost impossible or very expensive to obtain the statistical characteristics of the populations. Therefore a sample survey method is usually employed for stochastic methods. This paper describes the procedure of estimating the statistical characteristics of populations by employing sample data sets. An example of AFM micro cantilever beam is employed to show the effectiveness of the procedure.

• 대한기계학회논문집A
• /
• 제26권11호
• /
• pp.2415-2420
• /
• 2002

In the present study, a new anchor design was proposed to minimize the initial deflection of micro multi-layer cantilever beam with step-up structure, which is a key component of thin film micro-mirror array. It is important to minimize the initial deflection, caused by residual stress, because it reduces the performance of the actuation. Theoretical and experimental studies were conducted to examine the cause of the initial bending deflection. It was found that the bending deflection at the anchor of the cantilever beam was the primary source of initial deflection. Various anchor designs were proposed and the initial deflections for each design were calculated by finite element analysis. The analysis results were compared with experiments. To reduce the initial deflection a secondary support was added to the conventional structure. The optimal shapes were obtained by simulation and experiment. It was found from the analysis that the ratio or horizontal and vertical dimensions of secondary support was the governing factor, which affected the initial deflection.

• Structural Engineering and Mechanics
• /
• 제71권3호
• /
• pp.223-232
• /
• 2019

Since the actuators with small- scale structures may be exposed to external reciprocal actions lead to create undesirable loads causing instability, the buckling behaviors of them are interested to make reliable or accurate actions. Therefore, the purpose of this paper is to analyze plastic buckling behavior of the micro beam structures by adopting a Conventional Mechanism-based Strain Gradient plasticity (CMSG) theory. The effect of length scale on critical force is considered for three types of boundary conditions, i.e. the simply supported, cantilever and clamped - simply supported micro beams. For each case, the stability equations of the buckling are calculated to obtain related critical forces. The constitutive equation involves work hardening phenomenon through defining an index of multiple plastic hardening exponent. In addition, the Euler-Bernoulli hypothesis is used for kinematic of deflection. Corresponding to each length scale and index of the plastic work hardening, the critical forces are determined to compare them together.

• Structural Engineering and Mechanics
• /
• 제56권3호
• /
• pp.461-472
• /
• 2015

In this paper, the nonlinear static response of curled cantilever beam actuators subjected to the one-sided electrostatic field is focused on. By assuming the deflection function of electrostatically actuated beam, analytical approximate solutions are established via using Galerkin method to solve the equilibrium equation. The Pull-In voltages which determine the stability of the curled beam actuators are also obtained. These approximate solutions show excellent agreements with numerical solutions obtained by the shooting method and the experimental data for a wide range of beam length. Expressions of these analytical approximate solutions are brief and could easily be used to derive the effects of various physical parameters on MEMS structures.