• 한국마이크로전자및패키징학회:학술대회논문집
• /
• 한국마이크로전자및패키징학회 2000년도 Proceedings of 5th International Joint Symposium on Microeletronics and Packaging
• /
• pp.19-25
• /
• 2000

Dielectric polymer films produced from benzocyclobutene (BCB) formulations (CYCLOTENE＊ family resins) are known to possess many desirable properties for microelectronic applications; for example, low dielectric constant and dissipation factor, low moisture absorption, rapid curing on hot plate without reaction by-products, minimum shrinkage in curing process, and no Cu migration issues. Recently, BCB-based products for thick film applications have been developed, which exhibited excellent dissipation factor and dielectric constant well into the GHz range, 0.002 and 2.50, respectively. Derived from these properties, the applications are developed in: bumping/wafer level packaging, Ga/As chip ILD, optical waveguide, flat panel display, and lately in BCB-coated Cu foil for build-up board. In this paper, we review the relevant properties of BCB, then the application areas in bumping/wafer level packaging and BCB-coated Cu foil for build-up board.

• 마이크로전자및패키징학회지
• /
• 제25권4호
• /
• pp.1-7
• /
• 2018

As the performance and density of IC (integrated circuit) devices increase, power and signal integrities in the global interconnects of advanced packaging technologies are becoming more difficult. Thus, the global interconnect technologies should be designed to accommodate increased input/output (I/O) counts, improved power grid network integrity, reduced RC delay, and improved electrical crosstalk stability. This requirement resulted in the fine-pitch interconnects with a low-k dielectric in 3D packaging or wafer level packaging structure. This paper reviews an organic-inorganic hybrid material as a potential dielectric candidate for the global interconnects. An organic-inorganic hybrid material called polysiloxane can provide spin process without high temperature curing, an excellent dielectric constant, and good mechanical properties.

• 마이크로전자및패키징학회지
• /
• 제26권2호
• /
• pp.9-14
• /
• 2019

The newly discovered properties of periodic nanoscale patterns have increasingly sparked research interests in various fields. Along this direction, it is worth mentioning that there had been rare studies conducted on interference exposure, a method of creating periodic patterns. Additionally, these few studies seemed to validate the existence of only exact quadrangle shapes and dot patterns. This study asserted the formation of wavy patterns associated to using multiple exposures of the ratio of the first exposure intensity to the second exposure intensity. Such patterns were designed and constructed herein via overlapping of two Gaussian beams relative to certain rotation angles, and with a submicron structure fabricated based on a 360-nm continuous-wave laser. Results confirmed that the proposed double exposure laser interference lithography is able to create circular, elliptical and wavy patterns with no need for complex optical components.

• 마이크로전자및패키징학회지
• /
• 제28권1호
• /
• pp.21-29
• /
• 2021

Recently, semiconductor chips and electronic components are increasingly being used in IT devices such as wearable watches, autonomous vehicles, and smart phones. As a result, there is a growing concern about device malfunctions that may occur due to electromagnetic interference being entangled with each other. In particular, electromagnetic wave emissions from wearable or flexible smart devices have detrimental effects on human health. Therefore, flexible and transparent electromagnetic interference (EMI) shielding materials and films with high optical transmittance and outstanding shielding effectiveness have been gaining more attention. The EMI shielding films for flexible and transparent electronic devices must exhibit high shielding effectiveness, high optical transmittance, high flexibility, ultrathin and excellent durability. Meanwhile, in order to prepare this EMI shielding films, many materials have been developed, and results regarding excellent EMI shielding performance of a new materials such as carbon nano tube (CNT), graphene, Ag nano wire and MXene have recently been reported. Thus, in this paper, we review the latest research results to EMI shielding films for flexible and transparent device using the new materials.

• 마이크로전자및패키징학회지
• /
• 제28권1호
• /
• pp.13-20
• /
• 2021

GaN은 III-V족 화합물 반도체로 밴드갭을 조절하는 것이 가능하고 화학적으로 안정하기 때문에 다른 물질에 비해 산성, 염기성 용액에서 부식이 적다. 또한 GaN의 밴드갭이 물의 산화·환원 준위를 포함하고 있어 외부전압 없이 물 분해가 가능하다는 장점이 있다. 하지만 GaN 자체만으로는 태양광-수소 변환 효율(solar-to-hydrogen conversion efficiency, STH)이 낮아 이를 개선하기 위해 최근 활발한 연구가 이루어지고 있다. 본 총설에서는 GaN을 PEC 물분해의 광전극으로 사용하기 위한 방법들과 연구에 대해 정리하였다.

• 한국분말재료학회지
• /
• 제13권5호
• /
• pp.321-326
• /
• 2006

Electronic packaging involves interconnecting, powering, protecting, and cooling of semiconductor circuits fur the use in a variety of microelectronic applications. For microelectronic circuits, the main type of failure is thermal fatigue, owing to the different thermal expansion coefficients of semiconductor chips and packaging materials. Therefore, the search for matched coefficients of thermal expansion (CTE) of packaging materials in combination with a high thermal conductivity is the main task for developments of heat sink materials electronics, and good mechanical properties are also required. The aim of this work is to develop copper matrix composites reinforced with carbon nanofibers. The advantages of carbon nanofibers, especially the good thermal conductivity, are utlized to obtain a composite material having a thermal conductivity higher than 400 W/mK. The main challenge is to obtain a homogeneous dispersion of carbon nanofibers in copper. In this paper, a technology for obtaining a homogeneous mixture of copper and nanofibers will be presented and the microstructure and properties of consolidated samples will be discussed. In order to improve the bonding strength between copper and nanofibers, different alloying elements were added. The microstructure and the properties will be presented and the influence of interface modification will be discussed.

• 마이크로전자및패키징학회지
• /
• 제14권4호
• /
• pp.9-14
• /
• 2007

본 연구에서는 가속화 조건에서의 비전도성 접착제가 사용된 플립칩 패키지의 열적 신뢰성에 관하여 평가하였다. 실리콘 칩에 $17{\mu}m$두께의 Au 범프를 형성하고 무전해 Ni/Au 도금과 Cu 패드의 두께가 각각 $5{\mu}m$와 $25{\mu}m$로 형성된 연성 기판을 사용하여 플립칩 패키지를 형성하였다. 유리전이온도가 $72^{\circ}C$인 비전도성 접착제를 사용하여 플립칩을 접합시킨 후 열충격 시험과 항온항습 시험을 실시하였다. 열충격 싸이클과 항온항습 유지 시간이 증가할수록 플립칩 패키지의 전기 저항이 증가하는 것을 확인할 수 있었다. 이는 Au 범프와 Au 범프 사이의 균열, 칩과 비전도성 접착제 또는 기판과 비전도성 접착제 사이의 층간 분리에 의한 것으로 사료된다. 또한 항온항습 하에서의 전기 저항의 변화가 열충격하에서 보다 큰 것을 확인할 수 있었다. 따라서 비전도성 접착제가 사용된 플립칩 패키지는 온도보다 습기에 더욱 민감하다는 것을 알 수 있었다.

• 마이크로전자및패키징학회지
• /
• 제20권4호
• /
• pp.7-11
• /
• 2013

As thermosonic ball bonding is developed for more and more advanced applications in the electronic packaging industry, the control of process stresses induced on the integrated circuits becomes more important. If Cu bonding wire is used instead of Au wire, larger ultrasonic levels are common during bonding. For advanced microchips the use of Cu based wire is risky because the ultrasonic stresses can cause chip damage. This risk needs to be managed by e.g. the use of ultrasound during the impact stage of the ball on the pad ("pre-bleed") as it can reduce the strain hardening effect, which leads to a softer deformed ball that can be bonded with less ultrasound. To find the best profiles of ultrasound during impact, a numerical model is reported for ultrasonic bonding with capillary dynamics combined with a geometrical model describing ball deformation based on volume conservation and stress balance. This leads to an efficient procedure of ball bond modelling bypassing plasticity and contact pairs. The ultrasonic force and average stress at the bond zone are extracted from the numerical experiments for a $50{\mu}m$ diameter free air ball deformed by a capillary with a hole diameter of $35{\mu}m$ at the tip, a chamfer diameter of $51{\mu}m$, a chamfer angle of $90^{\circ}$, and a face angle of $1^{\circ}$. An upper limit of the ultrasonic amplitude during impact is derived below which the ultrasonic shear stress at the interface is not higher than 120 MPa, which can be recommended for low stress bonding.

• 마이크로전자및패키징학회지
• /
• 제11권4호
• /
• pp.13-22
• /
• 2004

MEMS 소자의 패키지는 일반적으로 패키징 과정에서 큰 온도변화를 받게 되는데, 이에 의한 패키지의 변형은 패키지 및 소자의 신뢰성에 큰 영향을 미칠 수 있다. 본 논문에서는 진동형 MEMS 자이로스코프 센서의 패키지를 대상으로 하여, 온도변화로 인한 열변형 거동에 대한 광학실험과 해석을 수행하였다. 이를 위하여 실시간 모아레 간섭계를 이용하여 각 온도단계에서 변위분포를 나타내는 간섭무늬를 얻고, 그로부터 MEMS 패키지의 굽힘변형 거동 및 인장변형에 대한 해석을 수행하였다. MEMS 칩과 EMC 및 PCB의 열팽창계수 차이로 인하여 패키지는 $125^{\circ}C$ 이하에서는 전체적으로 아래로 볼록한 굽힘변형이 발생하였으며, 온도 $140^{\circ}C$를 정점으로 그 이상의 온도에서는 반대의 굽힘변형이 발생하였다. MEMS의 주파수에 영향을 줄 수 있는 칩 자체의 수축변형률은 약 $481{\times}10^{-6}$로 측정되어서 MEMS 설계시 이를 고려하여야 함을 알 수 있다.

• 마이크로전자및패키징학회지
• /
• 제29권4호
• /
• pp.41-47
• /
• 2022

Ag sintering technologies have received great attention as it was applied to the inverter of Tesla's electric vehicle Model III. Ag sinter bonding technology has advantages in heat dissipation design as well as high-temperature stability due to the intrinsic properties of the material, so it is useful for practical use of SiC and GaN devices. This study was carried out to understand the sinter joining temperature effect on the robust Ag sintered joints in air without pressure within 10 min. Electroplated Ag finished Cu dies (3 mm × 3 mm × 2 mm) and substrates (10 mm × 10 mm × 2 mm) were introduced, respectively, and nano Ag paste was applied as a bonding material. The sinter joining process was performed without pressure in air with the bonding temperature as a variable of 175 ℃, 200 ℃, 225 ℃, and 250 ℃. As results, the bonding temperature of 175 ℃ caused 13.21 MPa of die shear strength, and when the bonding temperature was raised to 200 ℃, the bonding strength increased by 157% to 33.99 MPa. When the bonding temperature was increased to 225 ℃, the bonding strength of 46.54 MPa increased by about 37% compared to that of 200 ℃, and even at a bonding temperature of 250 ℃, the bonding strength exceeded 50 MPa. The bonding strength of Ag sinter joints was directly influenced by changes in the necking thickness and interfacial connection ratio. In addition, developments in the morphologies of the joint interface and porous structure have a significant effect on displacement. This study is systematically discussed on the relationship between processing temperatures and bonding strength of Ag sinter joints.