• 한국전기전자재료학회논문지
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• 제16권8호
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• pp.700-704
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• 2003

This paper describes on characteristics of 2" 3C-SiC wafer bonding using PECVD (plasma enhanced chemical vapor deposition) oxide and HF (hydrofluoride acid) for SiCOI (SiC-on-Insulator) structures and MEMS (micro-electro-mechanical system) applications. In this work, insulator layers were formed on a heteroepitaxial 3C-SiC film grown on a Si (001) wafer by thermal wet oxidation and PECVD process, successively. The pre-bonding of two polished PECVD oxide layers made the surface activation in HF and bonded under applied pressure. The bonding characteristics were evaluated by the effect of HF concentration used in the surface treatment on the roughness of the oxide and pre-bonding strength. Hydrophilic character of the oxidized 3C-SiC film surface was investigated by ATR-FTIR (attenuated total reflection Fourier transformed infrared spectroscopy). The root-mean-square suface roughness of the oxidized SiC layers was measured by AFM (atomic force microscope). The strength of the bond was measured by tensile strength meter. The bonded interface was also analyzed by IR camera and SEM (scanning electron microscope), and there are no bubbles or cavities in the bonding interface. The bonding strength initially increases with increasing HF concentration and reaches the maximum value at 2.0 ％ and then decreases. These results indicate that the 3C-SiC wafer direct bonding technique will offers significant advantages in the harsh MEMS applications.ions.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 G
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• pp.3313-3315
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• 1999

Si direct bonding(SDB) technology is very attractive for both Si-on-insulator(SOI) electric devices and MEMS applications because of its stress free structure and stability. This paper presents on pre-bonding according to HF pre-treatment conditions in Si wafer direct bonding. The characteristics of bonded sample were measured under different bonding conditions of HF concentration, and applied pressure. The bonding strength was evaluated by tensile strength method. The bonded interface and the void were analyzed by using SEM and IR camera respectively. A bond characteristic on the interface was analyzed by using IT- IR. Si-F bonds on Si surface after HF pre-treatment are replaced by Si-OH during a DI water rinse. Consequently, hydrophobic wafer was bonded by hydrogen bonding of Si $OH{\cdots}(HOH{\cdots}HOH{\cdots}HOH){\cdots}OH-Si$. The bond strength depends on the HF pre-treatment condition before pre- bonding (Min:$2.4kgf/crn^2{\sim}Max:14.9kgf/crn^2$)

• Journal of Welding and Joining
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• 제23권6호
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• pp.77-86
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• 2005

Low temperature bonding of the silicon and glass using the Spin-on Glass (SOG) has been conducted experimentally to figure out the effects of the SOG solution composition and process variables on bond strength using the Design of Experiment method. In order to achieve the high quality bond interface without rack, sufficient reaction time of the optimal SOG solution composition is needed along with proper pressure and annealing temperature. The shear strength under the optimal SOG solution composition and process condition was higher than that of conventional anodic bonding and similar to that of wafer direct bonding.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.874-877
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• 2001

SOI(Silicon-On-Insulator) technology is proposed as an alternative to bulk silicon for MEMS(Micro Electro Mechanical System) manufacturing. In this paper, we fabricated the SOI wafer with uniform active layer thickness by silicon direct bonding and mechanical polishing processes. Specially-designed electrostatic bonding system is introduced which is available for vacuum packaging and silicon-glass wafer bonding for SOG(Silicon On Glass) wafer. We demonstrated thermopile sensor and RF resonator using the SOI wafer, which has the merits of simple process and uniform membrane fabrication.

• 마이크로전자및패키징학회지
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• 제22권3호
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• pp.31-38
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• 2015

본 연구에서는 실리콘 웨이퍼의 고속 직접접합 공정을 위하여 상압 플라즈마와 함께 에어로젤 형태의 초순수 분사를 이용하여 표면처리 활성화 및 결함이 없는 실리콘 직접접합 공정을 개발하였다. 플라즈마 공정의 다양한 인자, 즉 $N_2$ 가스의 유량, CDA(clean dry air)의 유량, 플라즈마 헤드와 기판 간의 간격, 플라즈마의 인가전압이 플라즈마 활성화, 즉 친수화 처리에 미치는 영향을 접촉각 측정을 통하여 관찰하였다. 또한 열처리 온도 및 열처리 시간이 접합 강도에 미치는 영향을 연구하였으며, 접합 강도의 측정은 crack opening 방법을 이용하였다. 접합 강도가 제일 높은 최적의 열처리 조건은 $400^{\circ}C$의 열처리 온도 및 2 시간의 열처리 시간이었다. 플라즈마 스캔 속도 및 스캔 횟수를 실험계획법을 이용하여 최적화한 결과, 스캔 속도는 30 mm/sec, 스캔 횟수는 4 회에서 최적의 접합 강도를 나타내고 있었다. 열처리 조건과 플라즈마 활성화 조건을 최적화 한 후 직접접합을 하여 적외선투과현미경 등을 이용하여 관찰한 결과, 접합된 웨이퍼에서 접합 공정으로 인한 공극이나 결함은 관찰되지 않았다. 접합된 웨이퍼의 접합 강도는 평균 $2.3J/m^2$의 접합 강도를 나타내고 있었다.

• 한국전기전자재료학회논문지
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• 제15권4호
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• pp.301-307
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• 2002

Direct bonded SOI wafer pairs with $Si ll SiO_2/Si_3N_4 ll Si$ the heterogeneous insulating layers of SiO$_2$-Si$_3$N$_4$are able to apply to the micropumps and MEMS applications. Direct bonding should be executed at low temperature to avoid the warpage of the wafer pairs and inter-diffusion of materials at the interface. 10 cm diameter 2000 ${\AA}-SiO_2/Si(100}$ and 560 $\AA$- ${\AA}-Si_3N_4/Si(100}$ wafers were prepared, and wet cleaned to activate the surface as hydrophilic and hydrophobic states, respectively. Cleaned wafers were pre- mated with facing the mirror planes by a specially designed aligner in class-100 clean room immediately. We employed a heat treatment equipment so called fast linear annealing(FLA) with a halogen lamp to enhance the bonding of pre mated wafers We kept the scan velocity of 0.08 mm/sec, which implied bonding process time of 125 sec/wafer pairs, by varying the heat input at the range of 320~550 W. We measured the bonding area by using the infrared camera and the bonding strength by the razor blade clack opening method, respective1y. It was confirmed that the bonding area was between 80% and to 95% as FLA heat input increased. The bonding strength became the equal of $1000^{\circ}C$ heat treated $Si ll SiO_2/Si_3N_4 ll Si$ pair by an electric furnace. Bonding strength increased to 2500 mJ/$\textrm{m}^2$as heat input increased, which is identical value of annealing at $1000^{\circ}C$-2 hr with an electric furnace. Our results implies that we obtained the enough bonding strength using the FLA, in less process time of 125 seconds and at lowed annealing temperature of $400^{\circ}C$, comparing with the conventional electric furnace annealing.

• 한국전기전자재료학회논문지
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• 제11권10호
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• pp.815-819
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• 1998

The silicon-nirtide membrane structure for IR sensor was fabricated through the etching and the direct bonding. The PRO($PbTiO_3$ ) layer for a IR detection was coated on the membrane and its characteristics were measured. The a attack of PTO layer during the etching of silicon wafer as well as the thermal isolation of the IR detection layer were eliminated through the method of bonding/etching of silicon wafer. The surface roughness of the membrane was measured by AFM, the micro voids and the non-contacted area were inspected by the PTO layer were measured, too.

• 전자통신동향분석
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• 제36권3호
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• pp.23-33
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• 2021

Two main technologies of III-V/Si laser diode for optical communication, direct epitaxial growth, and wafer bonding were studied. Until now, the wafer bonding has been vigorously studied and seems promising for the ideal III-V/Si laser. However, the wafer bonding process is still complicated and has a limit of mass production. The development of a concise and innovative integration method for silicon photonics is urgent. In the future, the demand for high-speed data processing and energy saving, as well as ultra-high density integration, will increase. Therefore, the study for the hetero-junction, which is that the III-V compound semiconductor is directly grown on Si semiconductor can overcome the current limitations and may be the goal for the ideal III-V/Si laser diode.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 G
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• pp.2501-2503
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• 1998

In this paper, the silicon-nitride membrane structure for IR sensor was fabricated through the etching and the direct bonding. The PTO layer as a IR detection layer was deposited on the membrane and its characteristics were measured. The attack of PTO layer during the etching of silicon wafer as well as the thermal isolation of the IR detection layer can be solved through the method of bonding/etching of silicon wafer. Because the PTO layer of c-axial orientation raised thermal polarization without polling, the more integration capability can be achieved. The surface roughness of the membrane was measured by AFM, the micro voids and the non-contacted area were inspected by IR detector, and the bonding interface was observed by SEM. The polarization characteristics and the dielectric characteristics of the PTO layer were measured, too.

• Transactions on Electrical and Electronic Materials
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• 제1권1호
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• pp.6-11
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• 2000

The hydrogen plasma treatment of silicon wafers in the reactive ion-etching mode was studied for the application to silicon-on-insulator wafers which were prepared using the wafer bonding technique. The chemical reactions of hydrogen plasma with surface were used for both surface activation and removal of surface contaminants. As a result of exposure of silicon wafers to the plasma, an active oxide layer was found on the surface. This layer was rendered hydrophilic. The surface roughness and morphology were examined as functions of the plasma exposing time and power. In addition, the surface became smoother with the shorter plasma exposing time and power. The value of initial surface energy estimated by the crack propagation method was 506 mJ/㎡, which was up to about three times higher as compared to the case of conventional direct using the wet RCA cleaning method.