• Transactions on Electrical and Electronic Materials
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• 제15권2호
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• pp.91-95
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• 2014

This paper presents the structure and process technology of simple and low-cost wafer-level packaging (WLP) for thin film radio frequency (RF) devices. Low-cost practical micromachining processes were proposed as an alternative to high-cost processes, such as silicon deep reactive ion etching (DRIE) or electro-plating, in order to reduce the fabrication cost. Gold (Au)/Tin (Sn) alloy was utilized as the solder material for bonding and hermetic sealing. The small size fabricated WLP of $1.04{\times}1.04{\times}0.4mm^3$ had an average shear strength of 10.425 $kg/mm^2$, and the leakage rate of all chips was lower than $1.2{\times}10^{-5}$ atm.cc/sec. These results met Military Standards 883F (MIL-STD-883F). As the newly proposed WLP structure is simple, and its process technology is inexpensive, the fabricated WLP is a good candidate for thin film type RF devices.

• 한국세라믹학회지
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• 제54권5호
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• pp.400-405
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• 2017

$P_2O_5-ZnO-SiO_2-R_2O$ glasses were synthesized as a sealing material for large scale dye-sensitized solar cells (DSSC). Compositional effects of $P_2O_5$ and ZnO were examined by varying their contents. Their viscosity and glass stability at sintering temperatures of less than $550^{\circ}C$ were examined by flow button test. Glass transition temperature and structural change upon compositional change were investigated. Chemical stability against electrolyte was also examined by immersing the glasses in the electrolyte for 72 h at $85^{\circ}C$.

• 센서학회지
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• 제29권5호
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• pp.354-359
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• 2020

The high vacuum hermetic sealing technique ensures excellent performance of MEMS resonators. For the high vacuum hermetic sealing, the customization of anodic bonding equipment was conducted for the glass/Si/glass triple-stack anodic bonding process. Figure 1 presents the schematic of the MEMS resonator with triple-stack high-vacuum anodic bonding. The anodic bonding process for vacuum sealing was performed with the chamber pressure lower than 5 × 10^-6 mbar, the piston pressure of 5 kN, and the applied voltage was 1 kV. The process temperature during anodic bonding was 400 ℃. To maintain the vacuum condition of the glass cavity, a getter material, such as a titanium thin film, was deposited. The getter materials was active at the 400 ℃ during the anodic bonding process. To read out the electrical signals from the Si resonator, a vertical feed-through was applied by using through glass via (TGV) which is formed by sandblasting technique of cap glass wafer. The aluminum electrodes was conformally deposited on the via-hole structure of cap glass. The TGV process provides reliable electrical interconnection between Si resonator and aluminum electrodes on the cap glass without leakage or electrical disconnection through the TGV. The fabricated MEMS resonator with proposed vacuum packaging using three-layer anodic bonding process has resonance frequency and quality factor of about 16 kHz and more than 40,000, respectively.

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2003년도 기술심포지움 논문집
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• pp.239-242
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• 2003

Optical module package is a hermetic metal-ceramic package for carrying optical IC. In case of LD(laser diode) module, window is used for both the path of optical signal and hermetic sealing of package. So, window has the metallization pattern on the surface for brazing process with package wall. In this study, several method were investigated for metallization. Thin film, thick film and mixed method were used for fabrication of metallization pattern. After brazing process, hermeticity and adhesion strength were tested for characterization of metallization pattern.

• Journal of Information Display
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• 제3권1호
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• pp.11-16
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• 2002

This paper presents a study on the tubeless Plasma Display Panel (PDP) packaging using glass-to-glass electrostatic bonding with intermediate amorphous silicon. The bonded sample sealing the mixed gas with three species showed high strength ranging from 2.5 MPa to 4 MPa. The glass-to-glass bonding for packaging was performed at a low temperature of $180^{\circ}C$ by applying bias of 250 $V_{dc}$ in ambient of mixed gases of He-Ne(27 %)-Xe(3 %). The tubeless packaging was accomplished by bonding the support glass plate of $30mm{\times}50mm$ on the rear glass panel and the capping glass of $20mm{\times}20mm$. The 4-inch color AC-PDP with thickness of 8 mm was successfully fabricated and fully emitted as white color at a firing voltage of 190V.

• 마이크로전자및패키징학회지
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• 제15권2호
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• pp.29-36
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• 2008

본 연구에서는 MEMS 소자의 직접화 및 소형화에 필수적인 through-wafer via interconnect의 신뢰성 문제를 연구하였다. 이를 위하여 Au-Sn eutectic 접합 기술을 이용하여 밀봉(hermetic) 접합을 한 웨이퍼 레벨 MEMS 패키지 소자를 개발하였으며, 전기도금법을 이용하여 수직 through-hole via 내부를 구리로 충전함으로써 전기적 연결을 시도하였다. 제작된 MEMS 패키지의 크기는 $1mm{\times}1mm{\times}700{\mu}m$이었다. 제작된 MEMS패키지의 신뢰성 수행 결과 비아 홀(via hole)주변의 크랙 발생으로 패키지의 파손이 발생하였다. 구리 through-via의 기계적 신뢰성에 영향을 줄 수 있는 여러 인자들에 대해서 수치적 해석 및 실험적인 연구를 수행하였다. 분석 결과 via hole의 크랙을 발생시킬 수 있는 파괴 인자로서 열팽창 계수의 차이, 비아 홀의 형상, 구리 확산 현상 등이 있었다. 궁극적으로 구리 확산을 방지하고, 전기도금 공정의 접합력을 향상시킬 수 있는 새로운 공정 방식을 적용함으로써 비아 홀 크랙으로 인한 패키지의 파괴를 개선할 수 있었다.

• 한국세라믹학회지
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• 제50권1호
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• pp.57-62
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• 2013

We investigated the thermal and electrical properties of the $B_2O_3-ZnO-Bi_2O_3$ glass system as a sealing material in sheath heater modules. A composition with over 90 wt% $Bi_2O_3$ in the $B_2O_3-ZnO-Bi_2O_3$ system was glassified by controlling the cooling rate. The glass transition temperature and thermal expansion coefficient in bismate glass could be controlled by the minor ingredients of ZnO, $SiO_2$, $BaO_2$, and $K_2O$. The $B_2O_3-ZnO-Bi_2O_3$ glass system bonded well to metal, and bismate glass insulating properties were comparable to those of bismate glass $B_2O_3-ZnO-PbO$ glass system in a sheath heater module.

• 한국세라믹학회지
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• 제26권6호
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• pp.829-835
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• 1989

Devitrifing solder glasses in a specific group of glass ceramic materials are extensively used in hermetically sealing alumina electronics packages. Preferred frit glass compositions of this study consist of 37~40wt% PbO, 35~40wt% ZnO, 18~20wt% B2O3, 1~3wt% SiO2, 0~6wt% TiO2. The coated frit glasses crystallize during firing and form a strong hermetic seal. DTA and X-ray diffraction were used to characterize crystallization of the glass frit. Frit seal containing 2wt% TiO2 has crystallization temperature of 550~57$0^{\circ}C$ with surface nucleation. Frit seal containing 6wt% TiO2 has crystallization temperature of 515~5$25^{\circ}C$ with bulk nucleation, and the main crystalline phase was perovskite lead titanate having minus expansion coefficient. The average activation energy for the crystallization calculated from Ozawa equation was 65$\pm$10kcal/mol.

• 반도체디스플레이기술학회지
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• 제3권3호
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• pp.5-9
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• 2004

A new wafer level packaging scheme is presented as an alternative to MEMS package. The proof-of-concept structure is fabricated and evaluated to confirm the feasibility of the idea for MEMS wafer level packaging. The scheme of this work is developed using an electroplated tin (Sn) solder. The critical difference over conventional ones is that wafers are laterally bonded by solder reflow after LEGO-like assembly. This lateral bonding scheme has merits basically in morphological insensitivity and its better bonding strength over conventional ones and also enables not only the hermetic sealing but also its electrical interconnection solving an open-circuit problem by notching through via-hole. The bonding strength of the lateral bonding is over 30 Mpa as evaluated under shear and the hermeticity of the encapsulation is 2.0$\times10^{-9}$mbar.$l$/sec as examined by pressurized Helium leak rate. Results show that the new scheme is feasible and could be an alternative method for high yield wafer level packaging.

• 한국항공우주학회지
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• 제50권1호
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• pp.31-38
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• 2022

위성용 TR모듈이 지상용 또는 항공용 TR모듈과 다른 점은 높은 레벨의 진동, 충격과 같은 발사환경과 우주방사능, 진공, 온도 변화와 같은 궤도환경 고려가 필요하다는 것이다. 따라서 지상용 또는 항공용 요구사양과는 다른 전기적, 구조적 조건을 요구한다. 이에 따라 서론에서는 발사환경, 궤도환경에 대해서 서술하고, 본문에서는 위성용 TR모듈에서 GaN의 활용과 요구되는 조건을 충족하기 위한 설계 과정을 기술한다. 특히, 부품선정부터 Derating&RF Budget 설계, 공정설계, 열해석까지 각각 단계에서 고려할 설계요소에 대해서 서술한다.