• 반도체디스플레이기술학회지
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• 제21권3호
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• pp.74-79
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• 2022

In this study, the plasma corrosion resistance and the change in the number of contamination particles generated using the plasma etching process and cleaning process of coating parts for semiconductor plasma etching equipment were investigated. As the coating method, atmospheric plasma spray (APS) was used, and the powder materials were Y₂O₃ and Y₃Al₅O₁₂ (YAG). There was a clear difference in the densities of the coatings due to the difference in solubility due to the melting point of the powdered material. As a plasma environment, a mixed gas of CF₄, O₂, and Ar was used, and the etching process was performed at 200 W for 60 min. After the plasma etching process, a fluorinated film was formed on the surface, and it was confirmed that the plasma resistance was lowered and contaminant particles were generated. We performed a surface cleaning process using piranha solution(H₂SO₄(3):H₂O₂(1)) to remove the defect-causing surface fluorinated film. APS-Y₂O₃ and APS-YAG coatings commonly increased the number of defects (pores, cracks) on the coating surface by plasma etching and cleaning processes. As a result, it was confirmed that the generation of contamination particles increased and the breakdown voltage decreased. In particular, in the case of APS-YAG under the same cleaning process conditions, some of the fluorinated film remained and surface defects increased, which accelerated the increase in the number of contamination particles after cleaning. These results suggest that contaminating particles and the breakdown voltage that causes defects in semiconductor devices can be controlled through the optimization of the APS coating process and cleaning process.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제52권8호
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• pp.335-341
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• 2003

The composites were fabricated respectively 61vo1.% $\beta$ -SiC and 39vo1.% Ti $B_2$ spray-dried powders with the liquid forming additives of l2wt% $Al_2$ $O_3$＋ $Y_2$ $O_3$ by pressureless annealing at 1$700^{\circ}C$, 175$0^{\circ}C$, 180$0^{\circ}C$ for 4 hours. The result of phase analysis of composites by XRD revealed $\alpha$ -SiC(6H), Ti $B_2$, and YAG(A $l_{5}$ $Y_3$ $O_{12}$ ) crystal phase. The relative density, the Young's modulus and fracture toughness showed respectively the highest value of 92.97%, 92.88Gpa and 4.4Mpaㆍ $m^{\frac{1}{2}}$ for composites by pressureless annealing temperature 1$700^{\circ}C$ at room temperature. The electrical resistivity showed the lowest value of 8.09${\times}$10$^{-3}$ ㆍcm for composite by pressureless annealing temperature 1$700^{\circ}C$ at $25^{\circ}C$. The electrical resistivity of the SiC-Ti $B_2$ composites was all positive temperature cofficient resistance(PTCR) in the temperature ranges from $25^{\circ}C$ to $700^{\circ}C$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 C
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• pp.1538-1540
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• 2003

The composites were fabricated respectively 61vol.% ${\beta}$-SiC and 39vol.% $TiB_2$ spray-dried powders with the liquid forming additives of 12wt% $Al_2O_3+Y_2O_3$ by pressureless annealing at $1700^{\circ}C,\;1750^{\circ}C\;1800^{\circ}C$ for 4 hours. The result of phase analysis of composites by XRD revealed ${\alpha}$-SiC(6H), $TiB_2$, and YAG($Al_5Y_3O_{12}$) crystal phase. The relative density, the Young's modulus and fracture toughness showed respectively the highest value of 92.97%, 92.88Gpa and $4.4Mpa{\cdot}m^{1/2}$ for composites by pressureless annealing temperature $1700^{\circ}C$ at room temperature. The electrical resistivity showed the lowest value of $8.09{\times}10^{-3}{\Omega}{\cdot}cm$ for composite by pressureless annealing tempe rature $1700^{\circ}C$ at $25^{\circ}C$. The electrical resistivity of the SiC-$TiB_2$ composites was all positive temperature cofficient resistance (PTCR) in the temperature ranges from $25^{\circ}C$ to $700^{\circ}C$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1228-1229
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• 2008

The composites were fabricated 61[vol.%] ${\beta}$-SiC and 39[vol.%] $TiB_2$ powders with the liquid forming additives of 12[wt%] $Al_2O_3+Y_2O_3$ as a sintering aid by pressure or pressureless annealing at 1,650[$^{\circ}C$] for 4 hours. Reactions between SiC and transition metal $TiB_2$ were not observed in the microstructure and the phase analysis of the SiC-$TiB_2$ electroconductive ceramic composites. Phase analysis of SiC-$TiB_2$ composites by XRD revealed mostly of ${\alpha}$-SiC(6H), $TiB_2$, and In Situ $YAG(Al_5Y_3O_{12})$. The relative density, the flexural strength and the Young's modulus showed the highest value of 88.32[%], 136.43[MPa] and 52.82[GPa] for pressure annealed SiC-$TiB_2$ composites at room temperature. The electrical resistivity showed the lowest value of 0.0162[${\Omega}{\cdot}cm$] for pressure annealed SiC-$TiB_2$ composite at 25[$^{\circ}C$]. The electrical resistivity of the pressure annealed SiC-$TiB_2$ composite was positive temperature coefficient resistance (PTCR) but the electrical resistivity of the pressureless annealed SiC-$TiB_2$ composites was negative temperature coefficient resistance(NTCR) in the temperature ranges from 25[$^{\circ}C$] to 700[$^{\circ}C$].

• The Korean Journal of Ceramics
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• 제2권1호
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• pp.39-42
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• 1996

${\alpha}-SiC$ powder with or without the addition of 0.1 wt% of large ${\alpha}-SiC$ partices(seeds) was pressureless-sintered at $1950^{\circ}C$ for 0.5, 2, and 4 h using $Y_3Al_5 O_{12}$ (yttrium aluminum garnet, YAG) as a sintering aid. The materials without seeds had an equiaxed grain struture. In contrast, the materials with seeds sintered for 2 and 4 h had a duplex microstructure with large elongated grains and amall equiaxed grains. Addition of large ${\alpha}-SiC$ seeds into ${\alpha}-SiC$ accelerated the grain growth of some ${\alpha}-SiC$ grains during sintering and resulted in the increased fracture toughness of the sintered materials. The fracture toughnesses of materials with or without seeds sintered for 4 h were 6.6 and $5.2 MPa \;m^{12}$, respectively.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제51권4호
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• pp.141-146
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• 2002

The mechanical and electrical properties of the pressureless sintered SiC-TiB$_2$electroconductive ceramic composites were investigated as functions of the transition metal of TiB$_2$. The result of phase analysis for the SiC-TiB$_2$ composites by XRD revealed $\alpha$-SiC(6H), TiB$_2$, and YAG(Al$_{5}$Y$_3$O$_{12}$) crystal phases. The relative density showed the lowest 84.8% for the SiC-TiB$_2$composites added with 39vol.%TiB$_2$. Owing to crack deflection, crack bridging and YAG of fracture toughness mechanism, the fracture toughness showed the highest value of 7.8 MPa.m$^{1}$2/ for composites added with 39vol.%TiB$_2$under a pressureless annealing at room temperature. The electrical resistivity of the SiC-27vol.%TiB$_2$ composites was negative temperature coefficient resistance(NTCR), and the electrical resistivity of the besides SiC-27vol.%TiB$_2$composites was all positive temperature coefficient resistance(PCTR) in the temperature range of $25^{\circ}C$ to $700^{\circ}C$.EX>.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전기물성,응용부문
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• pp.75-77
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• 2001

The mechanical and electrical properties of the pressureless annealed SiC-$TiB_2$ electro conductive ceramic composites were investigated as functions of the transition metal of $TiB_2$. The result of phase analysis for the SiC-$TiB_2$ composites by XRD revealed $\alpha$-SiC(6H). $TiB_2$, and YAG($Al_5Y_3O_{12}$) crystal phase. The relative density showed the lowest 84.8% for the SiC-$TiB_2$ composites added with 39vol.%$TiB_2$. Owing to crack deflection, crack bridging and YAG of fracture toughness mechanism, the fracture toughness showed the highest value of $7.8\;MPa{\cdot}m^{1/2}$ for composites added with 39vol.%$TiB_2$ under a pressureless annealing at room temperature. The electrical resistivity of the SiC-27vol.%$TiB_2$ composites was negative temperature coefficient resistance(NTCR), and the electrical resistivity of the besides SiC-27vol.%$TiB_2$ composites was all positive temperature coefficient resistance(PTCR) in the temperature range of $25^{\circ}C$ to $700^{\circ}C$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.381-384
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• 2001

The $\beta$-SiC+ZrB$_2$ and $\beta$-SiC+TiB$_2$ceramic electroconductive composites were pressureless-sintered and annealed by adding l2wt% A1$_2$ $O_3$+Y$_2$ $O_3$(6 : 4wt%) powder as a function of sintering temperature. The relative density showed highest value of 84.92% of the theoretical density for SiC-TiB$_2$ at 190$0^{\circ}C$ sintering temperature. The phase analysis of the composites by XRD revealed of $\alpha$-SiC(6H), TiB$_2$, $Al_{5}$Y$_2$ $O_{12}$ and $\beta$-SiC(15R). Flexural strength showed the highest of 230 MPa for SiC-ZrB$_2$ composites sintered at 190$0^{\circ}C$. The vicker's hardness increased with increasing sintering temperature and showed the highest for SiC-ZrB$_2$ composites sintered at 190$0^{\circ}C$. Owing to YAG, the fracture toughness showed the highest of 6.50 MPa . m$^{1}$2/ for SiC-ZrB$_2$ composites at 190$0^{\circ}C$. The electrical resistivity was measured by the Rauw method from $25^{\circ}C$ to $700^{\circ}C$. The electrical resistivity of the composites showed the PTCR(Positive Temperature Coefficient Resistivity).).

• 한국세라믹학회지
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• 제52권4호
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• pp.229-233
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• 2015

Currently, the majority of commercial white LEDs are phosphor converted LEDs made of a blue-emitting chip and YAG yellow phosphor dispersed in organic silicone. However, silicone in high-power devices results in long-term performance problems such as reacting with water, color transition, and shrinkage by heat. Additionally, yellow phosphor is not applicable to warm white LEDs that require a low CCT and high CRI. To solve these problems, mixing of green phosphor, red phosphor and glass, which are stable in high temperatures, is common a production method for high-power warm white LEDs. In this study, we fabricated conversion lenses with LUAG green phosphor, SCASN red phosphor and low-softening point glass for high-power warm white LEDs. Conversion lenses can be well controlled through the phosphor content and heat treatment temperature. Therefore, when the green phosphor content was increased, the CRI and luminance efficiency gradually intensified. Moreover, using high heat treatment temperatures, the fabricated conversion lenses had a high CRI and low luminance efficiency. Thus, the fabricated conversion lenses with green and red phosphor below 90 wt% and 10 wt% with a sintering temperature of $500^{\circ}C$ had the best optical properties. The measured values for the CCT, CRI and luminance efficiency were 3200 K, 80, and 85 lm/w.

• 한국결정성장학회지
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• 제7권1호
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• pp.18-26
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• 1997

소결조제로 Y 3Alo012를 첨가한 {3- SiC 분말에 seed로서 1 wt%의 a- SiC 분말을 첨 가한 시편과 첨가하지 않은 시편을 1950$^{\circ}$C, argon 분위기에서 0.5~4시간 동안 소결하였다. S Seed로써 1 wt% a-SiC 분말의 첨가는 소결 도중에 길게 자란 업자틀의 성장을 가속시켰고, a a- SiC seed를 첨가한 시편에서 더 조대한 미세구조가 얻어졌다 .. a-SiC seed를 첨가하여 4시간 동안 소결한 시편의 파괴인성은 7.5 MPa'ml/2이었고, seed를 첨가하지 않은 시편의 파괴인성은 6 6.1 MPa'm1/2이었다 .. Seed를 첨가한 시편의 높은 파괴인성은 조대한 미세구조에 포함된 길게 자란 입자들에 의한 균열가교 기구의 활발한 작용에 기인한다.