• 센서학회지
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• 제14권5호
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• pp.357-361
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• 2005

Low-stress silicon nitride (LSN) thin films with embedded metal line have been developed as free standing structures to keep microspheres in proper locations and localized heat source for application to a chip-based sensor array for the simultaneous and near-real-time detection of multiple analytes in solution. The LSN film has been utilized as a structural material as well as a hard mask layer for wet anisotropic etching of silicon. The LSN was deposited by LPCVD (Low Pressure Chemical Vapor Deposition) process by varing the ratio of source gas flows. The residual stress of the LSN film was measured by laser curvature method. The residual stress of the LSN film is 6 times lower than that of the stoichiometric silicon nitride film. The test results showed that not only the LSN film but also the stack of LSN layers with embedded metal line could stand without notable deflection.

• 한국전기전자재료학회논문지
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• 제19권6호
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• pp.531-537
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• 2006

A micromachined piezoelectric microspeaker was fabricated with a highly c-axis oriented ZnO thin film on a silicon-nitride film having compressive residual stress. When it was measured 3 mm away from the microspeaker in open field, the largest sound pressure level produced by the fabricated microspeaker was about 91 dB at around 2.9 kHz for the applied voltage of $6\;V_{peak-to-peak}$. The key technologies to these successful results were as follows: (1) the usage of a wrinkled diaphragm caused by the high compressive residual stress of silicon-nitride thin film, (2) the usage of the highly c-axis oriented ZnO thin film.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 G
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• pp.2524-2526
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• 1998

In this paper, the residual stress and young's modulus of the p+ thin film have been estimated by using the electrostatic resonators. The electrostatic plate resonator with four corrugated bridges and another with four flat ones have been fabricated. The deflection of the plate has been calculated under the induced tension and the residual stress and compared with the dynamic test results. When the young's modulus of the p+ silicon is 125 GPa. The estimated residual stresses of the flat and the corrugated bridges are about 15 MPa and less than 5 MPa, respectively. It has been confirmed that the corrugated structure releases the residual tensile stress resulted from the heavy boron diffusion process.

• 한국공작기계학회논문집
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• 제17권3호
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• pp.14-19
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• 2008

In the semiconductor IC(Integrated Circuit) package, the top surface of silicon chip is directly attached to the area of the leadframe with a double-sided adhesive layer, in which the base layer have the upper adhesive layer and the lower adhesive layer. The IC package structure has been known to encounter a thermo-mechanical failure mode such as delamination. This failure mode is due to the residual stress on the adhesive surface of silicon chip and leadframe in the curing-cooling process. The induced thermal stress in the curing process has an influence on the cooling residual stress on the silicon chip and leadframe. In this paper, for the minimization of the chip surface damage, the adhesive topologies on the silicon chip are studied through the finite element analysis(FEA).

• 열처리공학회지
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• 제18권3호
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• pp.157-163
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• 2005

Effects of refinement of primary Si and residual stress on the mechanical properties of Aluminum B.390 alloy have been examined. Calcium was found to have an effect on the size of primary silicon particles. Primary silicon particle was refined as Ca content decreased. Refinement of primary Si particles led to an improvement in mechanical properties of the alloy; increase of elongation was prominent, above all. By the increase of compressive residual stress in the matrix alloy, tensile strength increased but elongation decreased.

• 한국세라믹학회지
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• 제53권3호
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• pp.349-353
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• 2016

We prepared a number of reaction-bonded silicon carbides (RBSCs) made from various mixing ratios of raw SiC particles, and investigated their microstructure and etch characteristics by Reactive Ion Etch (RIE). Increasing the amount of $9.5{\mu}m$-SiC particles results in a microstructure with relatively coarser Si regions. On the other hand, increasing that of $2.6{\mu}m$-SiC particles produces much finer Si regions. The addition of more than 50 wt% of $2.6{\mu}m$-SiC particles, however, causes the microstructure to become partially coarse. We also evaluated their etching behaviors in terms of surface roughness (Ra), density and weight changes, and microstructure development by employing Confocal Laser Scanning Microscope (CLSM) and Scanning Electron Microscope (SEM) techniques. During the etching process of the prepared samples, we confirmed that the residual Si region was rapidly removed and formed pits isolating SiC particles as islands. This leads to more intensified ion field on the SiC islands, and causes physical corrosion on them. Increased addition of $2.6{\mu}m$-SiC particles produces finer residual Si region, and thus decreases the surface roughness (Ra.) as well as causing weight loss after etching process by following the above etching mechanism.

• 대한기계학회논문집
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• 제16권10호
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• pp.1869-1876
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• 1992

본 연구에서는 고온에서 높은 강도특성을 유지하면서 동시에 내마모성이 뛰어 나 가스터어빈의 부재로서의 사용이 기대되는 탄화규소(SiC) 세라믹에 대하여, 고체입 자의 충격에 의해 생기는 손상에 미치는 입자의 재질 및 크기의 영향을 조사하였다. 또 각 형태의 손상발생 임계치와 강도저하에 미치는 입자크기의 영향에 관해서도 검토 하였다.

• 대한기계학회논문집
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• 제19권4호
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• pp.1033-1040
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• 1995

To simulate strength reliability and durability of ceramic parts under gas turbine application environments, particle impact damage behaviors in silicon carbide oxidized at 1673 K and 1523 K for 200 hours in atmosphere were investigated. The long-term oxidation produced a slight increase in the static fracture strength. Particle impact caused a spalling of oxide layer. The patterns of spalling and damage induced were dependent upon the property and impact velocity of the particle. Especially, the difference in spalling behaviors induced could be explained by introducing the formation mechanism of lateral crack and elastic-plastic deformation behavior at impact sit. At the low impact velocity regions, the oxidized SiC showed a little increase in the residual strength due to the cushion effect of oxide layer, as compared with the as-received SiC without oxide layer.

• 한국정밀공학회지
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• 제19권6호
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• pp.145-154
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• 2002

CMP (Chemical mechanical polishing) process was used to control the fine grinding process induced mechanical damage of Cz Silicon wafer. Characterization of mechanical damage was carried out using Nomarski microscope, magic mirror and also using angle lapping and lifetime scanner evaluation after heat treatment. Magic mirror and lifetime scanner were very useful for the residual damage pattern characterization and CMP process was effective on the reduction of fine grinding induced mechanical damage.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 A
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• pp.72-75
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• 1994

In this paper, a novel method to figure out the relative residual stress distribution along the depth of silicon diaphragms is presented Cantilevers with various thickness are fabricated by the time controlled etching method using EPW as an etchant. The boron concentration along the depth of the cantilevers is obtained by the TSUPREM IV simulation, and the etching time to get the proper thickness is calculated. By measuring deflections of the p+ silicon cantilevers the stress profile along the depth of diaphragm is calculated. The obtained stress profile is reasonable and useful to expect the deflection of cantilevers and the buckling of diaphragms.