전송선로에 적용한 Low-k 고분자 복합 잉크 개발

남현진,정재웅,서덕진,김지수,유종인,박세훈 한국마이크로전자및패키징학회 2022 마이크로전자 및 패키징학회지 Vol.29 No.2

As the chip size gets smaller, the width of the electrode line is also fine, and the density of interconnections is increasing. As a result, RC delay is becoming a problem due to the difference in resistance between the capacitor layer and the electrical conductivity layer. To solve this problem, the development of electrodes with high electrical conductivity and dielectric materials with low dielectric constant is required. In this study, we developed low dielectric ink by mixing commercial PSR which protect PCB's circuits from external factors and PI with excellent thermal property and low-k characteristics. As a result, the ink mixture of PSR and PI 10:3 showed the best results, with a dielectric constant of about 2.6 and 2.37 at 20 GHz and 28 GHz, respectively, and dielectric dissipation was measured at about 0.022 and 0.016. In order to verify the applicability of future applications, various line-width transmission lines produced on Teflon were evaluated, and as a result, the loss of transmission lines using low dielectric ink mixed with PI was 0.12 dB less on average in S21 than when only PSR was used. 칩사이즈가 작아짐에 따라 선폭 또한 미세화되면서 인터커넥션의 밀집정도가 증가하고 있다. 그로 인해 캐패시터 층과 전기전도층의 저항 차이로 인해 RC delay가 문제되고 있다. 이를 해결하기 위해서는 높은 전기전도도의 전극과 낮은 유전율의 유전체 개발이 요구된다. 본 연구에서는 PCB (Print Circuit Board)의 회로를 외부요인으로부터 보호하는 상용 PSR (photo solder resist)과 우수한 내열 및 저유전 특성을 보유한 PI (polyimide)를 혼합하여 저유전체 잉크 개발을 진행하였다. 그 결과 PSR과 PI를 10:3으로 혼합한 잉크가 가장 우수한 결과를 보였으며 20 GHz와 28 GHz에서 각각 유전 상수 약 2.6, 2.37을 보였고, 유전손실은 약 0.022, 0.016으로 측정되었다. 차후 어플리케이션 적용 가능성 검증을 위해 테프론에 제작된 다양한 선폭의 전송선로에 평가하였으며 그 결과, PSR만 사용했을 때보다 PI와 혼합한 저유전체 잉크를 사용한 전송선로의 손실이 S21에서 평균 0.12 dB 덜 감소한 결과를 보였다.

스트레처블 전극용 나노실버 페이스트 개발

남현진,남수용 한국화상학회 2020 한국화상학회지 Vol.26 No.1

신축성 전극은 높은 전도성, 우수한 치수 안정성 및 변형에 대한 낮은 저항 변화를 제공해야 한다. 따라서 본 연구에서는 나노 실버 페이스트를 전도성 물질로 선택하고 신축성 전극을 제작하기 위해 스크린 인쇄법을 사용했다. 두께 125㎛의 PET필름에 탄성 클리어플렉스 폴리우레탄 필름을 경화시킨 후, 블록 이소 시아네이트 경화제와 혼합 된 폴리에스텔 수지를 마스킹층으로 코팅하여 필름의 끈적임을 감소시켰다. 롤링 볼택 시험으로 폴리에스텔 마스킹층의 효과를 평가하였다. 제조된 투명 클리어플렉스 필름을 신축성 전극 기판으로서 사용하였다. 신축성 폴리우레탄 필름 상에 나노실버 페이스트 및 스크린 인쇄 공정을 사용하여 제조된 신축성 전극은 최대 100%의 변형률 범위에서 높은 전도성를 나타냈다. Stretchable electrodes must offer high conductivity, excellent dimensional stability, and low resistance change to strain. In this study, I chose nano silver paste as a conductive material and used a screen printing method to fabricate the stretchable electrode. After curing elastomeric clear flex polyurethane films with a thickness of 125㎛ on PET films, the polyester resin mixed with blocked isocyanate curing agent was coated as a masking layer to reduce the stickiness of the film. The effect of the polyester masking layer was examined using a rolling ball tack test. The prepared clear flex film were used as the stretchable electrode substrates. The stretchable electrodes fabricated by using nano silver paste and screen printing process on the stretchable polyurethane films showed high conductivity in a strain range of up to 100%.

성별 없는 스웨덴 화장실

남현진 샘터사 2021 월간 샘터 Vol.612 No.-

신축 가능한 에폭시 베이스 전도성 접착제 개발

남현진,임지연,이창훈,박세훈,Nam, Hyun Jin,Lim, Ji Yeon,Lee, Chang Hoon,Park, Se-Hoon 한국마이크로전자및패키징학회 2020 마이크로전자 및 패키징학회지 Vol.27 No.3

신축/유연한 전극을 무언가에 접착하거나 전극에 무언가를 접착하기 위해서는 전극의 특성에 맞는 전도성 접착제가 필요하다. 전도성 접착제는 접착성과 전도성이 필수적으로 요구된다. 특히 접착성 부분은 내구성과 내열성이 요구되며 기존 접착제와 다르게 전도성까지 보유해야한다. 그러기 위해서는 강도와 접착성이 좋은 에폭시를 접착제로 선정하였고 여기에 기존 주제와 경화제로 이루어진 2액형 소재가 아닌 가소제와 보강제까지 혼합하여 4액형 소재를 사용하여 신축/유연성을 고분자에 부여하였다. 전도성 필러는 비저항이 낮은 재료인 은으로 선정하였고 높은 전도성을 위해 3가지 모양의 Ag 입자를 사용해 패킹성을 높였다. 이렇게 개발된 전도성 접착제와 실제 판매되고 있는 에폭시 기반 전도성 접착제 2개와 전도성을 비교하였고 실제 판매되고 있는 제품보다 약 10배정도의 우수한 전도성 결과가 도출되었다. 그리고 가소제와 보강제 여부에 따른 전도성, 기계적 특성, 접착력, 강도를 평가하였다. 또한 120℃에서 5분 경화 후에 60%의 인장에도 문제가 없었으며 연필경도는 6H로 우수하게 측정되었다. 3M tape test를 통해 전극의 접착력을 확인한 결과 바인더의 배합 비율에 관계없이 모두 우수한 결과를 보였다. 전극 위에 Cu sheet를 전도성 접착제를 통해 부착시킨 후 접촉저항을 확인한 결과 0.3 Ω으로 우수한 성능을 보였다. To attach a stretchable/flexible electrode to something or something to on electrode, conductive adhesives must be stretchable/flexible to suit the properties of the electrode. In particular, conductive adhesive require durability and heat resistance, and unlike conventional adhesives, they should also have conductivity. To this end, Epoxy, which has good strength and adhesion, was selected as an adhesive, and a plasticizer and a reinforcement were mixed instead of a two-liquid material consisting of a conventional theme and a hardener, and a four-liquid material was used to give stretchability/flexibility to high molecules. The conductive filler was selected as silver, a material with low resistance, and for high conductivity, three shapes of Ag particles were used to increase packing density. Conductivity was compared with these developed conductive adhesives and two epoxy-based conductive adhesives being sold in practice, and about 10 times better conductivity results were obtained than products being actually sold. In addition, conductivity, mechanical properties, adhesion and strength were evaluated according to the presence of plasticizers and reinforcement agent. There was also no problem with 60% tensile after 5 minutes of curing at 120℃, and pencil hardness was excellently measured at 6H. As a result of checking the adhesion of electrodes through 3M tape test, all of them showed excellent results regardless of the mixing ratio of binders. After attaching the Cu sheet on top of the electrode through conductive adhesive, the contact resistance was checked and showed excellent performance with 0.3 Ω.

고주파수용 저유전 및 저손실의 폴리머-세라믹 타입 Photo Solder Resist

남현진,신민경,정재웅,조영빈,박윤식,유종인,박세훈 한국고분자학회 2023 폴리머 Vol.47 No.4

In this study, a photo solder resist(PSR) with excellent dielectric properties was developed using various materials, including self-developed polyimide, porous silica, anisole, surfactants, and photoinitiators with low dielectric constant, to modify PSR (MPSR). The resulting PSRs exhibited a dielectric constant of 1.899 and dielectric loss of 0.006 at 10 GHz. The MPSR film was shown to be capable of internal cleavage type photoinitiation and was able to be developed up to a line width of 80 μm, indicating potential for direct application in PCB patterning processes. Finally, the ﾠencapsulation process was performed on a transmission line fabricated on Teflon with a line width of 250 μm, and S11 ﾠand S21 values were confirmed in the range of 20 to 35 GHz. The MPSR exhibited superior characteristics to existing PSRs, with S11 showing an improvement of about -12 dB and S21 showing over 40% improvement in value.

상악 측절치 Torque control을 동반한 양악 치성 전돌증 환자의 치험예

남현진,박영철 연세대학교 치과대학 두개안면기형연구소 1996 연세임상교정 Vol.4 No.-

건조 방식과 온도에 따른 녹색 고춧가루의 품질 특성

남현진,이용재 한국식품저장유통학회 2020 한국식품저장유통학회지 Vol.27 No.1

The optimal drying conditions for fresh green hot peppers (Capsicum annuum. L) were investigated through hypobaric drying (HB) and hot-air drying (HA). HB was performed at temperature at 35℃, 40℃, 45℃ and 45℃ after 80% dried at 40℃ and HA was performed at 40℃, 50℃, 60℃ and 50℃ after 80% dried at 50℃. HB offered a lower drying temperature and reduced drying time. The quality of the vivid green color of the dried power was superior for peppers dried at 35 and 40℃ through HB and at 40℃ and 50℃ via HA to others. Considering the drying time, 40℃ HB (42 h) and 50℃ HA (23 h) were ideal compared to the other six treatments. Through both drying methods, the flesh and seeds of the peppers exhibited more significant brown discoloration with increasing temperature. Epidermis whitening, which is the discoloration of green hot peppers during drying, occurred at a higher rate at lower temperatures, resulting in a lighter green pepper powder through 35℃ HB and 40℃ HA. The water absorption index increased as the temperature lowered, but the water solubility index did not change. The capsiacinoids concentration did not vary between the powders undergoing 40℃ HB and 50℃ HA; however, the vitamin C concentration was higher in the powder subjected to 40℃ HB.

O2 플라즈마 표면 처리 공정 후 라미네이션 공정으로 제작된 흑연 페이스트 기반의 저비용 및 고감도 유연 압력 센서

남현진,강철,이승우,김선우,박세훈 한국마이크로전자및패키징학회 2022 마이크로전자 및 패키징학회지 Vol.29 No.4

Flexible pressure sensor was developed using low-cost conductive graphite as printed electronics. Flexible pressure sensors are attracting attention as materials to be used in future industries such as medical, games, and AI. As a result of evaluating various electromechanical properties of the printed electrode for flexible pressure sensors, it showed a constant resistance change rate in a maximum tensile rate of 20%, 30° tension/bending, and a simple pulse test. A more appropriate matrix pattern was designed by simulating the electrodes for which this verification was completed. Utilizing the Serpentine pattern, we utilized a process that allows simultaneous fabrication and encapsulation of the matrix pattern. One side of the printed graphite electrode was O2 plasma surface treated to increase adhesive strength, rotated 90 times, and two electrodes were made into one through a lamination process. As a result of pasting the matrix pattern prepared in this way to the wrist pulse position of the human body and proceeding with the actual measurement, a constant rate of resistance change was shown regardless of gender. 저렴한 전도성 흑연을 인쇄전자 공법으로 유연 압력 센서를 개발하였다. 유연 압력 센서는 의료, 게임, AI 등 미래 산업에 활용될 소재로 각광받고 있다. 유연 압력 센서용 인쇄전극을 다양한 전기-기계적 특성을 평가한 결과 최대인장률 20%, 30°의 인장/굽힘, 간이 맥박 시험에서 일정한 저항 변화율을 보였다. 이렇게 검증이 완료된 전극을 시뮬레이션하여 더 적합한 matrix 패턴을 설계하였다. Serpentine 패턴을 활용하여 matrix 패턴 제작과 인캡슐레이션을 동시에 진행할수 있는 공정을 활용하였다. 인쇄된 흑연 전극의 한쪽 면에 접착력 증가를 위한 O2 플라즈마 표면처리하고, 90°회전시켜, 라미네이션 공정을 통해 2개의 전극을 하나로 제작하였다. 이렇게 제작된 matrix 패턴을 인체의 손목 맥박 위치에 부착하여 실측을 진행한 결과 남녀 상관없이 일정한 저항 변화율을 보였다.

하악전치 결손과편측 scissor bite을 동반한 제Ⅰ급 부정교합의 치험예

남현진,유영규 연세대학교 치과대학 두개안면기형연구소 1996 연세임상교정 Vol.4 No.-

Effect of storage temperature on chilling injury of ‘Cheongdobansi’, an astringent persimmon of Korea

남현진,제병일,이용재 한국원예학회 2023 Horticulture, Environment, and Biotechnology Vol.64 No.6

Low-temperature storage is used to extend the postharvest storage of horticultural produce. However, during low-temperature storage, certain fruit exhibit physiological disorders and alterations, which is known as chilling injury (CI). Nevertheless, the cause and the details of CI symptoms are unclear. Here we report ‘Cheongdobansi’, an astringent persimmon that showed a pattern of CI development, initiating in the middle of the inner fl esh in contact with white pith, spreading along the vascular tissue, and ending by covering the upper mesocarp. CI critical temperature of ‘Cheongdobansi’ persimmon was 8 the maximum CI induction was at 5 °C. However, temperature showed very low CI induction at −1 and , indicating that −1 is the optimal storage temperature of ‘Cheongdobansi’ persimmon. This result aslo challenges the common idea of CI that lowering the temperature below the critical temperature worsens CI symptoms. Interestingly, the highest ethylene produc tion was detected at 2 °C, with very low occurrence of decay at this temperature, suggesting a new hypothesis that ethylene production might be involved in the inhibition of decay. Moreover, the increase in respiration and decrease in fi rmness of persimmons take precedence over the prominent CI symptoms, where jelly-like fl esh formation and electrolyte leakage occur. Electrolyte leakage showed a signifi cant increase after the onset of visible CI symptoms. Our results provide important clues, such as the correlation between the structure of vascular tissue and CI development in fruit, and between ethylene and CI decay, which are very useful for post-harvest storage of astringent persimmons for agricultural use.