• Proceedings of the KIEE Conference
• /
• 1996.07c
• /
• pp.1991-1993
• /
• 1996

This paper describes a standardized micromachinung project (SMP) performed at Seoul National University (SNU). The SNU SMP uses a 3-mask, 2-polysilicon surface micromaching process. The entire process is performed at SNU Inter-University Semiconductor Research Institute(ISRC). In this first SNU SMP attemp, 16 $1cm^2$ cells containing different designs were fabricated.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2005.11a
• /
• pp.362-363
• /
• 2005

The objectives of this paper are to achieve good planarization of the deposited film and to improve deposition efficiency of multi-layer structures by using surface-micromaching process in MEMS technology. Planarization characteristic of poly-Si film deposited on thin oxide layer with MEMS structures is evaluated with different slurries. Patterns used for this research have shapes of square, density, line, hole, pillar, and micro engine part. Advantages and disadvantages of CMP for MEMS structures are observed respectively by using the test patterns with structures larger than 1 um line width. Preliminary tests for material selectivity of poly-Si and oxide are conducted with two types of slurries: ILD1300 and Nalco2371. And then, the experiments were conducted based on the pretest.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1996.04a
• /
• pp.156-160
• /
• 1996

A vibrating angular rate sensor with tuning fork type resonator of microstructure (940*820 .mu. m$^{2}$) was designed and will be fabricated by polysilicon surface micromaching. The angular rate sensor is driven in a lateral direction by electrostatic force of comb drive electrodes, and vertical vibrations of the sensor, thich is detected capacitively, are produced by Coriolis forces due to an external angular rate. Mechanical Q factors and a difference between the frequencies of the two resonant modes, the driving mode and detecting mode, play a great role in increasing the sensitivity of the sensor. To be a highly sensitive sensor, it was designed to have as small frequency discrepancy of the two resonant modes as possible. Finite element method was used for the modal analysis. Several design parameters were selected and their contributions to the modal frequencies were investigated. A method was presented for tuning the detecting mode frequency by DC bias on the drive electrodes.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.608-611
• /
• 2003

In this paper, laser direct micromaching is developed to fabricate micro patterns using UV laser ( λ$_3$= 355 nm). Experimentally, laser beam paths mainly influences the surface shape quality. Thus. we proposed laser beam path generator by extracting shape data in a blueprint worked through CAD modeler and using genetic algorithm that considers the characteristics of laser beam. The results show that various shapes of micro patterns could be manufactured using proposed method in this paper.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2002.10a
• /
• pp.370-375
• /
• 2002

Recently, the interest on micro optical parts has increased rapidly with the development of technology related to microsystems. Among the optical parts, micro lens is one of the most broadly used micro parts. To mass-produce the micro lenses, it is very effective to use the mold insert and injection molding process. There are many methods to fabricate the mold insert for micro lenses: electroforming, etching, mechanical micromachining and so on. In this study, we fabricated the mold insert for micro lenses using a micro ball endmill to apply mechanical micromaching method and analyzed the effect of main process parameters such as spindle speed, feed rate, dwell time on the processed surface. Then, using fabricated the mold insert we fabricated the micro lenses through injection molding process.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.20 no.2
• /
• pp.156-161
• /
• 2007

This paper describes the characteristics of polycrystalline ${\beta}$ or 3C (cubic)-SiC (silicon carbide) thin films heteroepitaxailly grown on Si wafers with thermal oxide. In this work, the poly 3C-SiC film was deposited by APCVD (atmospheric pressure chemical vapor deposition) method using HMDS (hexamethyildisilane: $Si_{2}(CH_{3}_{6})$ single precursor. The deposition was performed under various conditions to determine the optimized growth conditions. The crystallinity of the 3C-SiC thin film was analyzed by XPS (X-ray photoelectron spectroscopy), XRD (X-ray diffraction) and FT-IR (fourier transform-infrared spectometers), respectively. The surface morphology was also observed by AFM (atomic force microscopy) and voids or dislocations between SiC and $SiO_{2}$ were measured by SEM (scanning electron microscope). Finally, depth profiling was invesigated by GDS (glow discharge spectrometer) for component ratios analysis of Si and C according to the grown 3C-SiC film thickness. From these results, the grown poly 3C-SiC thin film is very good crystalline quality, surface like mirror and low defect. Therfore, the poly 3C-SiC thin film is suitable for extreme environment, Bio and RF MEMS applications in conjunction with Si micromaching.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.50 no.5
• /
• pp.243-248
• /
• 2001

In this paper, we present theoretical and experimental study on the viscous damping of the on-substrate torsional micromirrors, oscillating near the silicon substrates. In this theoretical study, we develop theoretical models and test structures for the viscous damping of the on-substrate torsional micromirrors. From a finite element analysis, we estimate the theoretical damping coefficients of the torsional micromirrors. From a finite element analysis, we estimate the theoretical damping coefficients of the torsional micromirrors, fabricated by the surface-micromaching process. From the electrostatic test of the fabricated devices, frequency-dependent rotationalvelocity of the micromirrors has been measured at the atmospheric pressure using devices, frequency-dependent rotational velocity of the micromirrors has been measured at the atmospheric pressure using the Mach-Zehnder interferometer system. Experimental damping coefficients have been extracted from the least square fit of the measured rotational velocity within the filter bandwidth of 150 kHz. We have compared the theoretical values and the experimental results on the dynamic performance of the micromirrors. The theoretical analysis overstimates the resonant frequency in the amount of 15%, while underestimating the viscous damping in the factors of 10%.