• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2000.07a
• /
• pp.557-560
• /
• 2000

Combination of SDB(Si-wafer Direct Bonding) and electrochemical etch-stop in TMAH anisotropic etchant can be used to create a variety of MEMS(Micro Electro Mechanical System). Especially, fabrication of SDB SOI structures using electrochemical etch-stop is accurate method to fabrication of 3D(three-dimensional) microstructures. This paper describes on the fabrication of SDB SOI structures with sealed cavity for MEMS applications and thickness control of active layer on the SDB SOI structure by electrochemical etch-stop. The flatness of fabricated SDB SOI structure is very uniform and can be improved by addition of TMAH to IPA and pyrazine.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2000.11a
• /
• pp.579-582
• /
• 2000

This paper described on the fabrication of SOI(Si-on-insulator) structures with buried cavities by SDB technology and eletrochemical etch-stop. The cavity was fabricated the upper handling wafer by Si anisotropic etch technique. SDB process was performed to seal the fabricated cavity under vacuum condition at -760mmHg. In the SDB process, captured air and moisture inside of the cavities were removed by making channels towards outside. After annaling(100$0^{\circ}C$, 60 min.), the SDB SOI structure was thinned by electrochemical etch-stop. Finally, it was fabricated the SDB SOI structure with buried cavities as well as an accurate control and a good flatness.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.49 no.2
• /
• pp.180-187
• /
• 2022

The aim of this study was to investigate the risk factors associated with sleep disordered breathing (SDB) by comparing intraoral factors, body mass index (BMI), and medical history with pediatric sleep questionnaire (PSQ) findings. Seven hundred eighty-seven subjects aged between 7 to 11 years old were included. Their caregivers were asked to complete questionnaires. Oral manifestations including Angle's classification, overjet, and Brodsky tonsil grade were examined. Children with PSQ scores of more than 0.33 points were classified into the SDB high-risk group. Among the 787 subjects, 34 (4.3%) were classified into the SDB high-risk group. Children with allergic rhinitis, atopic dermatitis, excessive overjet, or large tonsil size had a significantly higher risk for SDB versus those without. Also, there was a significant difference in SDB risk according to BMI status. Gender, gestational age, breastfeeding, and Angle's classification were not associated with SDB. Children at high risk for SDB were predisposed to tonsillar hypertrophy, allergic rhinitis, obesity, and atopic dermatitis. Children with these factors could be candidates for early intervention to prevent the progression of SDB.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.11 no.1
• /
• pp.41-54
• /
• 2013

Radionuclide sorption data is necessary for the safety assessment of radioactive waste disposal. However the use of sorption database is often limited due to the accessability. A web-based sorption database program named KAERI-SDB has been developed to provide information on the sorption of radionuclides onto geological media as a function of geochemical conditions. The development of KAERI-SDB was achieved by improving the performance of pre-existing sorption database program (SDB-21C) developed in 1998 and considering user's requirements. KAERI-SDB is designed that users can access it by using a web browser. Main functions of KAERI-SDB include (1) log-in/member join, (2) search and store of sorption data, and (3) chart expression of search results. It is expected that KAERI-SDB could be widely utilized in the safety assessment of radioactive waste disposal by enhancing the accessibility to users who wants to use sorption data. Moreover, KAERI-SDB opened to public would also improve the reliability and public acceptance on the radioactive waste disposal programs.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.49 no.4
• /
• pp.357-367
• /
• 2022

Sleep disordered breathing (SDB) is a disease characterized by repeated hypopnea and apnea during sleep due to complete or partial obstruction of upper airway. The prevalence of pediatric SDB is approximately 12 - 15%, and the most common age group is preschool children aged 3 - 5 years. Children show more varied presentations, from snoring and frequent arousals to enuresis and hyperactivity. The main cause of pediatric SDB is obstruction of the upper airway related to enlarged tonsils and adenoids. If SDB is left untreated, it can cause complications such as learning difficulties, cognitive impairment, behavioral problems, cardiovascular disease, metabolic syndrome, and poor growth. Pediatric dentists are in a special position to identify children at risk for SDB. Pediatric dentists recognize clinical features related to SDB, and they should screen for SDB by using the pediatric sleep questionnaire (PSQ), lateral cephalometry radiograph, and portable sleep monitoring test and refer to sleep specialists. As a therapeutic approach, maxillary arch expansion treatment, mandible advancement device, and lingual frenectomy can be performed. Pediatric dentists should recognize that prolonged mouth breathing, lower tongue posture, and ankyloglossia can cause abnormal facial skeletal growth patterns and sleep problems. Pediatric dentists should be able to prevent these problems through early intervention.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.15 no.11
• /
• pp.958-962
• /
• 2002

This paper reports on the fabrication of free-standing microstructures by DRIE (deep reactive ion etching). SOI (Si-on-insulator) structures with buried cavities are fabricated by SDB (Si-wafer direct bonding) technology and electrochemical etch-stop. The cavity was formed the upper handling wafer by Si anisotropic etch technique. SDB process was performed to seal the formed cavity under vacuum condition at -760 mmHg. In the SDB process, captured air and moisture inside of the cavities were removed by making channels towards outside. After annealing (100$0^{\circ}C$, 60 min.), the SDB SOI structure with a accurate thickness and a good roughness was thinned by electrochemical etch-stop in TMAH solution. Finally, it was fabricated free-standing microstructures by DRIE. This result indicates that the fabrication technology of free-standing microstructures by combination SDB, electrochemical etch-stop and DRIE provides a powerful and versatile alternative process for high-performance bulk micromachining in MEMS fields.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1995.05a
• /
• pp.227-229
• /
• 1995

Using thermal oxide SiO$_2$ as a dielectrical isolation layer, SOI Hall sensors without pn junction isolation have been fabricated on Si/SiO$_2$/Si structures. The SOI structure was formed by SDB (Si- wafer direct bonding) technology. The Hall voltage and the sensitivity of Si Hall devices implemented on the SDB SOI structure show good linearity with respect to the appled magnetic flux density and supplied current. The product sensitivity of the SDB SOI Hall device is average 600V/V.T. In the trmperature range of 25 to 300$^{\circ}C$, the shifts of TCO(Temperature Coefficient of the Offset Voltage) and TCS(Temperature Coefficient of the Product Sensitivity) are less than ${\pm}$ 6.7x10$\^$-3/ C and ${\pm}$8.2x10$\^$04/$^{\circ}C$, respectively. These results indicate that the SDB SOI structure has potential for the development of Hall sensors with a high-sensitivity and high-temperature operation.

• Proceedings of the KIEE Conference
• /
• 2001.07c
• /
• pp.1890-1892
• /
• 2001

This paper described on the fabrication of microstructures by DRIE(Deep Reactive Ion Etching). SOI(Si-on-insulator) electric devices with buried cavities are fabricated by SDB technology and electrochemical etch-stop. The cavity was fabricated the upper handling wafer by Si anisotropic etch technique. SDB process was performed to seal the fabricated cavity under vacuum condition at -750 mm Hg. In the SDB process, captured air and moisture inside of the cavities were removed by making channels towards outside. After annealing(1000$^{\circ}C$, 60 min.), the SDB SOI structure was thinned by electrochemical etch-stop. Finally, it was fabricated microstructures by DRIE as well as a accurate thickness control and a good flatness.

• Sleep Medicine and Psychophysiology
• /
• v.8 no.1
• /
• pp.11-17
• /
• 2001

In 2000, the number of people aged 65 and over increased to 3.37 million, accounting for 7.1% of the total population of South Korea. The elderly population will increase up to 19.3% in 2030. Sleep disordered breathing (SDB) seems to increase with age. More than 50-60% of old people complain of SDB-related signs and symptoms including awakening headache, excessive daytime sleepiness, fatigue, cognitive dysfunction, memory loss, personality changes, and depression. The influence of a mild degree of SDB upon the elderly is unclear, but moderate to severe SDB is well known to be associated with many diseases including hypertension, arrhythmia, myocardial infarction, stroke, dementia, and sudden death. Therefore, physicians should pay attention to elderly patients who complain of SDB related symptoms and signs that may not be normal signs of aging. Physicians need to become more sensitive to treat SDB in the elderly.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.13 no.5
• /
• pp.431-436
• /
• 2000

This paper describes on the fabrication of a SOI substrate by SDB technology and electrochemical etch-stop. The surface of the thinned SDB SOI substrate is more uniform than that of grinding or polishing by mechanical method and this process was found to be a very accurate method for SOI thickness control. During electrochemical etch-stop leakage current versus voltage curves were measured for analysis of the open current potential(OCP) point the passivation potential(PP) point and anodic passivation potential. The surface roughness and the controlled thickness selectivity of the fabricated a SDB SOI substrate were evaluated by using AFM and SEM respectively.