• Transactions on Electrical and Electronic Materials
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• v.7 no.4
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• pp.184-188
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• 2006

This work describes efforts in the fabrication and testing of robust microelectromechanical systems (MEMS). Robustness is typically achieved by investigating non-silicon substrates and materials for MEMS fabrication. Some of the traditional MEMS fabrication techniques are applicable to robust MEMS, while other techniques are drawn from other technology areas, such as electronic packaging. The fabrication technologies appropriate for robust MEMS are illustrated through laminated polymer membrane based pressure sensor arrays. Each array uses a stainless steel substrate, a laminated polymer film as a suspended movable plate, and a fixed, surface micromachined back electrode of electroplated nickel. Over an applied pressure range from 0 to 34 kPa, the net capacitance change was approximately 0.14 pF. An important attribute of this design is that only the steel substrate and the pressure sensor inlet is exposed to the flow; i.e., the sensor is self-packaged.

• Journal of the Microelectronics and Packaging Society
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• v.26 no.4
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• pp.157-161
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• 2019

Independent control of electronic and thermal transport behaviors is one of the most effective approaches to enhance the performance of thermoelectric materials. To address this, many researches on the relationship between defect structures and thermoelectric properties have been carried out since defects are intrinsic ingredients of polycrystalline materials. Recently, experimental results of simultaneously improved electronic and thermal transport properties have been reported via the formation of 0-dimensional point defects. Here, theoretical backgrounds to the engineering of electronic and thermal transport behaviors by the formation of point defects are discussed and related experimental considerations are also presented in order to provide a practical guide for the development of highperformance thermoelectric materials.

• Journal of the Microelectronics and Packaging Society
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• v.25 no.4
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• pp.95-99
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• 2018

High thermal conductivity films with electrically insulating properties have a great potential for the effective heat transfer as substrate and thermal interface materials in high density and high power electronic packages. There have been lots of studies to achieve high thermal conductivity composites using high thermal conductivity fillers such alumina, aluminum nitride, boron nitride, CNT and graphene, recently. Among them, hexagonal-boron nitride (h-BN) nano-sheet is a promising candidate for high thermal conductivity with electrically insulating filler material. This work presents an enhanced heat transfer properties of ceramic/polymer composite films using h-BN nano-sheets and PVA polymer resins. The h-BN nano-sheets were prepared by a mechanical exfoliation of h-BN flakes using organic media and subsequent ultrasonic treatment. High thermal conductivities over $2.8W/m{\cdot}K$ for transverse and $10W/m{\cdot}K$ for in-plane direction of the cast films were achieved for casted h-BN/PVA composite films. Further improvement of thermal conductivity up to $13.5W/m{\cdot}K$ at in-plane mode was achieved by applying uniaxial compression at the temperature above glass transition of PVA to enhance the alignment of the h-BN nano-sheets.

• Journal of the Microelectronics and Packaging Society
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• v.22 no.3
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• pp.1-7
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• 2015

In this study, properties of Pb-free solders for automotive electronics parts were discussed. Lead-free solders for electronics became important after RoHS (Restriction of the use of certain Hazardous Substances) to avoid environmental pollution. Also the growing electronic rate in automotive parts and ELV (End-of Life Vehicles) make Pb-free solder for automotive electronics to be inevitable trend. Definitely, Pb-free solder for automotive electronics should have good wettability, basic strength, but need more reliability than other solders, since it has harsh condition like high temperature, humidity and engine vibration. Thus, shear strength test, thermal shock, drop test and many others are needed to ensure the high reliability. This study describes the properties and requirements of Pb-free solders for automotive electronics.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 1999.11a
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• pp.111-115
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• 1999

The $Li_2O-MgO-MgF_2-SiO_2$glasses with addition of $B_2O_3$ were investigated in order to make glass-ceramics for low temperature firing substrate. Glasses were made by melting at $1450^{\circ}C$ in the electronic furnace and crystallized at $750^{\circ}C$. After the crystallization, crystal phases and microstructure were observed. The crystal phases were polycrystalline of lithium boron fluorphlogopite and lithium fluorhectorite. The crystal shape was changed to grande type from needle type with the increase in $B_2O_3$ contents. Average particle size of the glass-ceramics aftar water swelling was $3.77{\mu}{\textrm}{m}$. The optimum sintering temperature and sintering shrinkage of the substrate were $900^{\circ}C$ and 13.4vol%, respectively.

• Journal of the Microelectronics and Packaging Society
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• v.20 no.4
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• pp.1-6
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• 2013

Recently, various types of flexible devices such as flexible displays, batteries, e-skins and solar cell panels have been reported. Most of the researches focus on the development of high performance flexible device. However, to realize these flexible devices, the long-term reliability should be guaranteed during the repeated deformations of flexible devices because the direct mechanical stress would be applied on the electronic devices unlike the rigid Si-based devices. Among various materials consisting electronics devices, metal electrode is one of the weakest parts against mechanical deformation because the mechanical and electrical properties of metal films degrade gradually due to fatigue damage during repeated deformations. This article reviews the researches of fatigue behavior of thin metal film, and introduces the methods to enhance the reliability of metal electrode for flexible device.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.1
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• pp.137-143
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• 2008

Thermal fatigue life prediction for solder joints becomes the most critical issue in present microelectronic packaging industry. And lead-free solder is quickly becoming a reality in electronic manufacturing fields. This trend requires life prediction models for new solder alloy systems. This paper describes the life prediction models for SnAgCu and SnPb solder joints, based upon non-linear finite element analysis (FEA). In case of analyses of the SnAgCu solder joints, two kinds of shapes are used. As a result, it is found that the SnAgCu solder has longer fatigue life than the SnPb solder in temperature cycling analyses.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2003.04a
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• pp.1-19
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• 2003

The electronic market thrust for many hybrid circuit manufacturers is changing because commercial market segments such as telecommunications, automotive and consumer electronics have increased the demand world wide for environmentally friendly thick film products. This, in turn, places a stronger emphasis on the material suppliers within the circuit fabrication industry to provide toxin free products with equal or higher performance than traditional technology. A new group of silver based thick film conductors, which are totally free of such toxins as cadmium, nickel and Bead have been developed to meet new environmental requirements. Traditional thick film products and newly developed toxin free compositions will be compared and data will be presented. To evaluate their performance, both groups of conductors were tested for solder acceptance, leach resistance and aged adhesion with standard lead-containing solder and higher temperature lead-free solder.

• Journal of the Microelectronics and Packaging Society
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• v.11 no.4 s.33
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• pp.49-53
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• 2004

Polymeric materials are widely used in the electronic industry as a common dielectric material or adhesive. The polymeric layer coated on Si substrate can be subjected to thermal stresses due to difference in thermal expansion coefficients. The mismatch in thermal properties between the polymeric layer and the substrate results in significant residual stresses. In this study, the thermal deformation is measured by a curvature measurement method using laser scanning, and the elastic modulus is calculated by an analytic model.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.1
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• pp.17-29
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• 2023

In this paper, a method for evaluating the reliability of solder joints is introduced, as they play a crucial role in packaging technology due to the miniaturization and high-performance requirements of electronic device. Firstly, properties of solder based on various alloy compositions and solder types are described, followed by an analysis of solder joint structures in different packages. Next, the influence of solder alloy composition and microstructure on the thermal and mechanical properties of solder is analyzed, and solder creep behavior is briefly introduced. Subsequently, analytical techniques considering creep models and fatigue models for reliability evaluation are presented, and various ways to improve the reliability of solder joints are discussed. This study is expected to provide valuable information for evaluating and enhancing the reliability of solder joints in the semiconductor packaging technology field.