Advanced Packaging Materials Research Articles

Mechanism of formation of fibrous eutectic Si and thermal conductivity of SiC p /Al-20Si composites solidified under high pressure

Abstract As an advanced electronic packaging material, SiC p /Al-20Si composites have been fabricated by high pressure solidification. The mechanism of formation of fibrous eutectic Si and the thermal conductivity (TC) behavior of the composites have been systematically investigated. High pressure decreases diffusion of Si phase significantly; moreover, SiC addition hinders the diffusion and provides nucleation sites for the Si phase. Both high pressure and SiC contribute to the formation of fibrous eutectic Si. The SiC p /Al-20Si composite solidified at 3 GPa exhibits lowest TC due to the formation of a supersaturated Al(Si) solid solution, whereas it is highest after ageing treatment. The optimal TC of the 45% SiC p /Al-20Si composite is 166.8 W/m·K at room temperature. The TC of the composites can be well predicted by the Hasselman-Johnson (H-J) theoretical model.

Engineering estimation of time-dependent deformation characteristics as bending moment relaxation and released unfolding motion of creased paperboard

Paperboards are recognized to be important raw materials for packaging industry due to their advantages such as high strength-to-weight ratio, recyclability. Regarding the development of advanced packaging materials and the requirement of smart formed products, a study of sheet’s response behaviour is necessary for expanding the advanced converting industry. After introducing a couple of past research works concerned crease technologies, a fundamental mechanisms of crease deformation is reviewed using the scoring depth and the folding angle of a paperboard. Since one of important forming characteristics is a time-dependent stress relaxation or time-delayed strain during a fold/unfold process, the author’s experimental approaches for estimating a short term (less than 10 seconds) dynamic deformation behaviour of creased paperboard are discussed.

Double-Wall Nanotubes and Graphene Nanoplatelets for Hybrid Conductive Adhesives with Enhanced Thermal and Electrical Conductivity

Improving the electrical and thermal properties of conductive adhesives is essential for the fabrication of compact microelectronic and optoelectronic power devices. Here we report on the addition of a commercially available conductive resin with double-wall carbon nanotubes and graphene nanoplatelets that yields simultaneously improved thermal and electrical conductivity. Using isopropanol as a common solvent for the debundling of nanotubes, exfoliation of graphene, and dispersion of the carbon nanostructures in the epoxy resin, we obtain a nanostructured conducting adhesive with thermal conductivity of ∼12 W/mK and resistivity down to 30 μΩ cm at very small loadings (1% w/w for nanotubes and 0.01% w/w for graphene). The low filler content allows one to keep almost unchanged the glass-transition temperature, the viscosity, and the curing parameters. Die shear measurements show that the nanostructured resins fulfill the MIL-STD-883 requirements when bonding gold-metalized SMD components, even after repeated thermal cycling. The same procedure has been validated on a high-conductivity resin characterized by a higher viscosity, on which we have doubled the thermal conductivity and quadrupled the electrical conductivity. Graphene yields better performances with respect to nanotubes in terms of conductivity and filler quantity needed to improve the resin. We have finally applied the nanostructured resins to bond GaN-based high-electron-mobility transistors in power-amplifier circuits. We observe a decrease of the GaN peak and average temperatures of, respectively, ∼30 °C and ∼10 °C, with respect to the pristine resin. The obtained results are important for the fabrication of advanced packaging materials in power electronic and microwave applications and fit the technological roadmap for CNTs, graphene, and hybrid systems.

LDPE composite films incorporating ceramic powder emitting far‐infrared radiation for advanced food‐packaging applications

ABSTRACTA ceramic powder that emits far‐infrared radiation (FIR) was incorporated into low‐density polyethylene (LDPE) via melt‐compounding and subsequent melt‐extrusion processes. To investigate the feasibility of as‐prepared LDPE/FIR composite films for use in packaging applications, the composite films were characterized using Fourier transform infrared spectroscopy, X‐ray diffraction, scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry, FIR emissivity and emissive power, antimicrobial activity assays, and storage tests. The physical properties and antimicrobial activities of the composite films were found to strongly correlate with the changes in the chemical and morphological structures that originate from different contents of FIR ceramic powder. A higher content of FIR ceramic powder in the LDPE/FIR composite film provided increased FIR emissivity and emission power of the composite and resulted in good antimicrobial activity. Storage tests also showed that incorporation of FIR ceramic powder into LDPE film was an effective method for maintaining the freshness of lettuce. Furthermore, the incorporation of FIR ceramic powder into LDPE films induced higher thermal stability and crystallinity and enhanced their barrier properties, which suggest these LDPE/FIR composite films are potential candidates for advanced packaging materials for the food and medical industries. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43102.

Advanced Materials for High Temperature, High Performance, Wide Bandgap Power Modules

Advanced packaging materials must be utilized to take full advantage of the benefits of the superior electrical and thermal properties of wide bandgap power devices in the development of next generation power electronics systems. In this manuscript, the use of advanced materials for key packaging processes and components in multi-chip power modules will be discussed. For example, to date, there has been significant development in silver sintering paste as a high temperature die attach material replacement for conventional solder-based attach due to the improved thermal and mechanical characteristics as well as lower processing temperatures. In order to evaluate the bond quality and performance of this material, shear strength, thermal characteristics, and void quality for a number of silver sintering paste materials were analyzed as a die attach alternative to solder. In addition, as high voltage wide bandgap devices shift from engineering samples to commercial components, passivation materials become key in preventing premature breakdown in power modules. High temperature, high dielectric strength potting materials were investigated to be used to encapsulate and passivate components internal to a power module. The breakdown voltage up to 30 kV and corresponding leakage current for these materials as a function of temperature is also presented. Lastly, high temperature plastic housing materials are important for not only discrete devices but also for power modules. As the operational temperature of the device and/or ambient temperature increases, the mechanical strength and dielectric properties are dramatically reduced. Therefore, the electrical characteristics such as breakdown voltage and leakage current as a function of temperature for housing materials are presented.

Microstructure and properties of Al/Sip composites for thermal management applications

Aluminum matrix composite reinforced with high amount of Si particle is an advanced electronic packaging material used in thermal management. In this work, Al/Sip composites with different Si contents were prepared by rapid solidification and hot pressing. Fine and homogeneous microstructures with defect-free were achieved, and no detrimental reaction was detected. The typical thermo-physical properties such as the thermal conductivity and coefficient of thermal expansion (CTE) of the Al/Sip composites were acceptable as electronic packaging material for semiconductor devices. The CTE increased gradually with the temperature. Additionally, the mechanical properties of the composites were measured. The technological performance (workability, platability, and laser weldability) of the composites were also evaluated.

Research on the Application of 3D Printing Technology in the Field of Packaging

3D printing technology has brought technology innovations for each industry, there is no exception in the field of packaging. This paper mainly introduces the characteristics and advantages of 3D printing technology, its application progress in products packaging design and packaging material forming, and finally summarizes the application trend of 3D printing technology. 3D printing technology can not only make complex and personalized packaging design possible, but also dig more advanced packaging materials, and make the formation of packaging materials quickly, 3D printing technology has very broad prospects of development in the field of packaging.

Thermal Expansion Behavior of the Electroless Copper Coated Cu-SiC<sub>p</sub> Composites Fabricated via the Conventional Powder Metallurgical Technique

The introduction of the metal matrix composites as the advanced electronic packaging materials is highly anticipated because their thermal properties can be engineered to match those of semiconductors, ceramics substrates and optical fibers. Among these advanced packaging materials, silicon carbide particles reinforced copper matrix (Cu-SiCp) composites are highly rated due to the high thermal conductivity of copper and low coefficient of thermal expansion (CTE) of silicon carbide. However, the Cu-SiCp composites fabricated via the conventional powder metallurgy (PM) technique usually have immature thermophysical properties due to the weak bonding between the copper matrix and the SiCp reinforcement. In order to improve the bonding between the two constituents, the SiCp were coated with copper via electroless coating process prior to PM fabrication processes. Based on the experimental results, The CTE and porosity of the Cu-SiCp composites were significantly affected by the volume fraction of SiCp. Furthermore, the CTE and porosity of the Cu-Coated Cu-SiCp composites were significantly lower than the non-Coated Cu-SiCp composites. These differences were mainly contributed by the nature of the bonding between the copper matrix and SiCp reinforcement.

A High Temperature, Fast Switching SiC Multi-chip Power Module (MCPM) for High Frequency (> 500 kHz) Power Conversion Applications

In high frequency power conversion applications, the dominant mechanism attributed to power loss is the turn-on and -off transition times. To this end, a full-bridge silicon carbide (SiC) multi-chip power module (MCPM) was designed to minimize parasitics in order to reduce over-voltage/current spikes as well as resistance in the power path. The MCPM was designed and packaged using high temperature (> 200 °C) materials and processes. Using these advanced packaging materials and devices, the SiC MCPM was designed to exhibit low thermal resistance which was modeled using three-dimensional finite-element analysis and experimentally verified to be 0.18 °C/W. A good agreement between the model and experiment was achieved. MCPMs were assembled and the gate leakage, drain leakage, on-state characteristics, and on-resistance were measured over temperature. To verify low parasitic design, the SiC MCPM was inserted into a boost converter configuration and the switching characteristics were investigated. Extremely low rise and fall times of 16.1 and 7.5 ns were observed, respectively. The boost converter demonstrated an efficiency of > 98.6% at 4.8 kW operating at a switching frequency of 250 kHz. In addition, a peak efficiency of 96.5% was achieved for a switching frequency of 1.2 MHz and output power of 3 kW.

A Review of Carbon Nanotube Ensembles as Flexible Electronics and Advanced Packaging Materials

The exceptional electronic, thermal, mechanical, and optical characteristics of carbon nanotubes offer significant improvement in diverse applications such as flexible electronics, energy conversion, and thermal management. We present an overview of recent research on the fabrication, characterization and modeling of carbon nanotube (CNT) networks or ensembles for three emerging applications: thin-film transistors for flexible electronics, interface materials for thermal management and transparent electrodes for organic photovoltaics or light emitting diodes. Results from experimental measurements and numerical simulations to determine the electrical and thermal transport properties and characteristics of carbon nanotube networks and arrays used in the above applications are presented. The roles heterogeneous networks of semiconducting and metallic CNTs play in defining electrical, thermal, and optical characteristics of CNT ensembles are presented. We conclude with discussions on future research directions for electronics and packaging materials based on CNT ensembles.

Printing enzymatic reactions

We used relief and planographic printing methods to print the catalytic effect of an enzyme, but not the enzyme molecules, onto paper. Printing enzymatic reactions have applications in bioactive papers, low-cost diagnostics, anti-counterfeiting devices and advanced packaging materials. These methods can create novel printing effects on commodity surfaces for advanced applications.

A low-viscousity, highly thermally conductive epoxy molding compound (EMC)

Advanced epoxy molding compounds (EMCs) should be considered to alleviate the thermal stress problems caused by low thermal conductivity and high elastic modulus of an EMC and by the mismatch of the coefficient of thermal expansion (CTE) between an EMC and the Si-wafer. Though AlN has some advantages, such as high thermal conductivity and mechanical strength, an AlN-filled EMC could not be applied to commercial products because of its low fluidity and high modulus. To solve this problem, we used 2-μm fused silica, which has low porosity and spherical shape, as a small size filler in the binary mixture of fillers. When the composition of the silica in the binary filler system reached 0.3, the fluidity of EMC was improved more than twofold and the mechanical strength was improved 1.5 times, relative to the 23-μm AlN-filled EMC. In addition, the values of the elastic modulus and the dielectric constant were reduced to 90%, although the thermal conductivity of EMC was reduced from 4.3 to 2.5W/m-K, when compared with the 23μm AlN-filled EMC. Thus, the AlN/silica (7/3)-filled EMC effectively meets the requirements of an advanced electronic packaging material for commercial products, such as high thermal conductivity (more than 2W/m-K), high fluidity, low elastic modulus, low dielectric constant, and low CTE.

A NEW PROCESS FOR FABRICATING CONVEX CORNERS IN SILICON

International Journal of Computational Engineering ScienceVol. 04, No. 02, pp. 307-310 (2003) Silicon MicromachiningNo AccessA NEW PROCESS FOR FABRICATING CONVEX CORNERS IN SILICONXIAO LIN ZHANG, JANAK SINGH, AJAY AGARWAL and Q. X. ZHANGXIAO LIN ZHANGInstitute of Microelectronics, Singapore 117684, Singapore Search for more papers by this author , JANAK SINGHInstitute of Microelectronics, Singapore 117684, Singapore Search for more papers by this author , AJAY AGARWALInstitute of Microelectronics, Singapore 117684, Singapore Search for more papers by this author and Q. X. ZHANGInstitute of Microelectronics, Singapore 117684, Singapore Search for more papers by this author https://doi.org/10.1142/S1465876303001149Cited by:0 PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail AbstractThis paper presents an innovative process scheme to fabricate convex corner in silicon for bulk micro-machined micro-mirror. This method combines deep reactive ion etching (DRIE) with anisotropy wet KOH etching process, with corner compensation structures. Using this method, proper mechanical structure, including about 650μm deep silicon recess with flat, silicon — residue free bottom, V-grooves, and U-grooves are realised simultaneously in single wafer. References Chad B. O'Neal et al., "Challenge in Packaging of MEMS" IEEE 1999 Proceedings International Symposium on Advanced Packaging Materials. Processes, Properties and Interfaces . Google Scholar Kato Y., Mori K., Mase T., Takahashi A., Imaki O., Kaku R., "Development of 4 × 4 MEMS optical switch" Optical MEMS, 2000 IEEE/LEOS International Conference Page(s): 95-96 . Google Scholar L. S. Huang, et al., "MEMS packaging for micro mirror switch", in Proc. 48th IEEE Electron. Components Technol. Conf., Seattle WA, 25-28, 1998 . Google Scholar P. Helin, M. Mita, H. Fujita, "Self-aligned vertical mirror and V-grooves: Appilied to a self-latching matrix switch for optical networks", Proceedings IEEE Thirteenth Annual International Conference on Micro Electro Mechanical Systems 2000 . Google Scholar Ki-Chang Song et al., "Micromachined Silicon Optical Bench for the Low Cost Optical Module", Technical Report, LG Electronics Institute of Technology . Google ScholarBen Kloecket al., IEEE Transactions on Electron Devices 36(4), (1989). Google Scholar FiguresReferencesRelatedDetails Recommended Vol. 04, No. 02 Metrics History PDF download