분말제조한 고망간강에서 소결 및 열처리 조건이 기계적 성질에 미치는 영향

방재철,홍종휘,조성석 대한금속재료학회 1989 대한금속재료학회 학술대회 개요집 Vol.1989 No.1

필러 첨가에 의한 OLED의 레이저 실링용 P2O5-V2O5-ZnO 유리프릿의 제조

방재철 한국전기전자재료학회 2015 전기전자재료학회논문지 Vol.28 No.9

In this study, we developed a lead-free P2O5-V2O5-ZnO glass frit for sealing OLED using laser irradiation. The frit satisfied the characteristics required for laser sealing such as low glass transition temperature, low coefficient of thermal expansion (CTE), high water-resistance, and high absorption at the wavelength of the laser beam. Ceramic fillers were added to the glass frit in order to further reduce and match its CTE with that of the commercial glass substrate. The addition of Zirconium Tungsten Phosphate (ZWP) to the frit yielded the most desirable results, reducing the CTE to 45.4×10-7/℃, which is very close to that of the glass substrate (44.0×10-7/℃). Successful formation of a solid sealing layer was observed by optical and scanning electron microscopy. 본 연구에서 레이저 조사에 의한 OLED 실링에 적합한 무연 P2O5-V2O5-ZnO 유리프릿을 개발하였다. 프릿은 낮은 유리전이온도, 낮은 열팽창계수, 높은 내수성, 높은 레이저빔 파장의 흡수 특성 등 레이저 실링을 위한 요구 조건을 충족시켰다. 열팽창 계수를 추가로 낮추어 상용 유리기판의 수치에 맞추기 위해 세라믹 필러를 유리프릿에 첨가하였다. 지르코니움 텅스텐 포스페이트 (ZWP) 세라믹 필러가 가장 효과가 우수하여, 유리기판의 CTE 값인 44.0×10-7/℃에 거의 근접한 45.4×10-7/℃ 값을 나타냈다. 견고한 실링층이 성공적으로 형성된 것을 광학 및 전자현미경으로 확인하였다.

B₂O₃ 가 첨가된 (Zn_0.8Mg_0.2)TiO₃ 마이크로파 유전체 세라믹스의 저온소결

방재철,Bang, Jae-Cheol 한국전기전자재료학회 2006 전기전자재료학회논문지 Vol.19 No.1

The effects of $B_2O_3$ addition on the low-temperature sintering behavior and microwave dielectric properties of $(Zn_{0.8}Mg_{0.2})TiO_3$ ceramic system were investigated. Highly dense samples were obtained at the sintering temperatures below $900^{\circ}C$. The $Q{\times}f_o$ values were determined by the microstructures and sintering shrinkages which are affected by the amount of $B_2O_3$ and sintering temperature. Temperature coefficient of resonance frequency($T_f$) changes to a positive value with increasing the amount of $B_2O_3$ due to the increased amount of rutile phase which is one of the reaction products between $(Zn_{0.8}Mg_{0.2})TiO_3$ and $B_2O_3$. For $6.19 moi.{\%}B_2O_3$-added $(Zn_{0.8}Mg_{0.2})TiO_3$ system, it exhibits ${\epsilon}_r$ = 23.5, $Q{\times}f_o$ = 53,000 GHz, and $T_f$ = 0 ppm/$^{\circ}C$ when sintered at $900^{\circ}C$ for 5 h.

고온용 정전기척의 유전층 개발에 관한 연구

방재철 한국마이크로전자및패키징학회 2001 마이크로전자 및 패키징학회지 Vol.8 No.3

고온용 정전기척(high-temperature electrostatic chuck, HTESC)에 적합한 특성의 유전재료를 개발하였다. 유전층의 전기비저항과 유전상수 값은 HTESC가 적합하게 작동하기에 필요한 요구조건을 만족하였으며, 하부절연층재료와 열팽창계수가 유사하여 구조적인 안정성이 확보되었다. 유전층과 절연 층간의 접합층 재료로는 입자오염 문제의 최소화를 위해 붕규산염 유리재료를 선택하였고, 전극재료로는 은을 사용하였다. 상부유전 층과 하부절연층 사이에서 붕규산염 유리는 안정되게 접합되었으며, 우려 되었던 은전극의 유전층이나 유리층과의 확산 및 반응이 관찰되지 않았다. 제조된 HTESC의 척킹(chucking)특성은 상용 HTESC에 비하여 우수하게 나타났다. Dielectric material which is suitably designed for the application of the high-temperature electrostatic chucks(HTESCS) has been developed. Electrical resistivities and dielectric constants of the dielectric layer satisfy the demands for the proper operation of HTESC, and coefficient of thermal expansion(CTE) of the dielectric material matches well that of the bottom insulator so that it secures stable structure. In order to minimize particle contaminations, borosilicate glass(BSG) is selected as a bonding layer between dielectric layer and bottom insulator, and silver is used as a electrode. BSG is solidly bonded between upper dielectric and bottom insulator, and no diffusions or reactions are observed among silver electrode, dielectric, and glass layers. The chucking characteristics of the fabricated HTESC are found to be superior to those of the commercialized one.

Glass + Ceramic의 구속 소결에 관한 연구

방재철 순천향대학교 부설 산업기술연구소 1998 순천향 산업기술연구소논문집 Vol.3 No.3

The densification behavior of constrained films of borosilicate glass (BSG) + silica system was studied because of their applications in microelectronic packaging technologies. Optical measurement techniques were devised to determine the shrinkage profiles of the free and constrained films and in-plane stress in the constrained films. These films were prepared from slurries of the powder by tape casting. Sintering was carried out isothermally in a hot stage between 715℃ and 775℃. The densification rates of both films were observed to be the same in the early stage of sintering but slowed down in the constrained film during the later stage resulting in a lower density. The activation energies for both free and constrained sintering were found to be 385±10 kJ/mol. In-plane stress measurements in constrained films of the pure glass showed the stress to rapidly rise to a maximum level of 20 kPa during the initial stage of sintering and gradually decreased back to zero during the final stage. Densification rates can be given as a product of mobility and driving pressure. Activation energy determinations did not indicate a change in the densification mechanism such that a change in mobility can be ruled out as the reason for the reduced densification rate in constrained films. The stresses are substantially smaller than the estimated lower limit of the sintering pressure and had no observed effect on the densification of the constrained film during the early stages of sintering . However, the stresses could have prevented a few large pores from shrinking during the early stage of sintering leading to the lower density and larger pores observed in the constrained film after sintering.

MgCo_(2)(VO_(4))_(2) 세라믹스의 마이크로파 유전특성

방재철 순천향대학교 부설 산업기술연구소 2004 순천향 산업기술연구소논문집 Vol.10 No.2

The effects sintering additives such as xwt%(0.242Bi_(2)O_(3)-0.758V_(2)O_(5)) on the microwave dielectric and sintering properties of MgCo_(2)(VO_(4))_(2) ceramics were investigated. Highly dense samples were obtained for MgCo_(2)(VO_(4))_(2) at the sintering temperature of 950℃ with 0.242Bi_(2)O_(3) - 0.758V_(2)O_(5) additions of 0.5 ~ 5wt%. The microwave dielectric properties of MgCo_(2)(VO_(4))_(2) with 0.5wt%(0.242Bi_(2)O_(3)-0.758V_(2)O_(5)) sintered at 950℃ were as follow : Qxf_(0)=45,375㎓, ε_(r) = 9.7 and τ_(f) = -23.2ppm/℃

유전체 결정화유리 정전기 척의 제조와 특성

방재철 순천향대학교 부설 산업기술연구소 1998 순천향 산업기술연구소논문집 Vol.3 No.3

This paper discusses the research work done on the development of a high-temperature electrostatic chuck (HTESC) based on a molybdenum substrate coated with a glass-ceramic dielectric layer. Molybdenum substrates were coated with chromium by sputtering followed by tape casting of a thin layer of glass-ceramic slurry. The coated substrates were then fired at 950℃ in a furnace under a vacuum atmosphere. After the firing, the interfaces between molybdenum/chromium and glass-ceramic/chromium were obsered to be very stable without any delaminations at the interfaces. Electrical resistivity measurements on the glass-ceramic films show that this material retains a proper resistivity at temperatures up to 500℃. Clamping pressure measurements showed that it produced a force of up to 15 torr which is sufficient to meet a demand for HTESC.

저온소결 (Zn_0.8Mg_0.2)TiO₃ 세라믹의 마이크로파 유전특성에 관한 연구

방재철,심우성 한국전기전자재료학회 2003 전기전자재료학회논문지 Vol.16 No.7

The effects of sintering additives such as B $i_2$ $O_3$ and $V_2$ $O_{5}$ on the microwave dielectric and sintering properties of (Z $n_1$$_{-xM}$ $g_{x}$)Ti $O_3$ system were investigated. Highly dense samples were obtained for (Z $n_{0.8}$M $g_{0.2}$)Ti $O_3$ at the sintering temperature range of 870~90$0^{\circ}C$ with B $i_2$ $O_3$ and $V_2$ $O_{5}$ additions of 〈1 wt.%, respectively. The microwave dielectric properties of (Z $n_{0.8}$M $g_{0.2}$)Ti $O_3$ with 0.45 wt.%B $i_2$ $O_3$ and 0.55 wt.% $V_2$ $O_{5}$ sintered at 90$0^{\circ}C$ were as follows : Q$\times$ $f_{o}$ = 50,800 GHz, $\varepsilon$$_{r}$ = 22, and $\tau$$_{f}$ = -53 ppm/$^{\circ}C$. In order to improve temperature coefficient of resonant frequency, Ti $O_2$ was added to the above system. The optimum amount of Ti $O_2$ was 15 moi.% when sintered at 87$0^{\circ}C$, at which we could obtain following results: Q$\times$ $f_{o}$ = 32,800 GHz, $\varepsilon$$_{r}$ = 26, and$\tau$$_{f}$ = 0 ppm/$^{\circ}C$.EX>.EX>.EX>.EX>.EX>.EX>.EX>.

인공치아용 생체유리의 조성별 물성 연구

방재철,김예솔,박예찬,손지은,홍예린 순천향대학교 부설 산업기술연구소 2019 순천향 산업기술연구소논문집 Vol.25 No.1

Bioactive glasses of different compositions have been produced and tested to compensate for the low biological activity of the zirconia that is currently used as an artificial tooth. XRD was measured on a weekly basis after immersion in simulated body fluid(SBF) for eight weeks to assess whether the bioactive layer was formed. The XRD analysis showed that all specimens produced tricalcium phosphate(TCP) from Week 6 and that the hardness and fracture toughness values of the specimen were increased compared to the initial specimen.

세라믹계 정전기 척의 개발

방재철 호서대학교반도체제조장비국산화 연구센터 2000 반도체 장비기술 논문집 Vol.2000 No.-

세라믹 도포형 정전기척(electrostatic chuck, ESC)을 제조하기 위하여 ESC 작동에 적합한 특성의 상부절연층 세라믹 재료를 개발하였고 단계별 제조공정의 최적화를 통하여 사용화를 위한 샘플을 제작하였다. 개발된 상부절연층의 전기비저항과 유전상수 값은 요구조건을 만족하였으며 하부 절연층재료와 열팽창계수가 유사하여 구조적인 안정성이 확보되었다. 한편, 상 . 하부 절연층간의 접합을 견고히 하고 기존의 ESC 에서 발생된 입자오염 문제를 최소화 하기 위해 붕규산염 유리재료를 중간접합층으로 선택하여 조건별로 시험하였으며, 전극재료로는 은을 선택하여 여러조건에서 시험하였다. 붕규산염 유리는 상 . 하부 절연층과 사용된 은전극과의 젖음성이 우수하고 접합력도 강했으며 은전극은 우려되었던 유리층과의 확산 및 반응이 거의 없었다. 제조된 ESC의 척킹(chucking)특성은 상용 ESC 나 이전 연구에서 제작된 ESC 에 비하여 고착력이 우수하여 나타났다.