Papers by Keyword: Packaging

Abstract: This paper presents a comparative analysis of 1200 V Silicon Carbide (SiC) MOSFETs characterized at bare die level and in TO-247 packaging. Static parameters including transconductance (g_m), drain leakage current (I_DS-OFF), output (I_DS-V_DS) and transfer characteristics (I_DS-V_GS), gate threshold voltage (V_GS(th)) and on-state resistance (R_DS(on)) are examined. Results show that the TO-247 package introduces parasitic resistance/inductance and higher thermal impedance, leading to disrupted g_m, though lower leakage I_DS-OFF, shifted V_GS(th), and elevated R_DS(on). The study quantifies the discrepancy between intrinsic die behavior and packaged device performance, underscoring the need to de-embed packaging effects for accurate device modelling and optimization.

Abstract: With the continuous advancement of SiC device design and manufacturing processes, devices of the same ratings are achieving higher turn-on speeds and smaller chip areas. These improvements enhance the speed and power density of power electronic systems but also pose greater challenges for thermal management and the parasitic parameters of packaging. To address these issues, this paper proposes a multi-chip SiC power module packaging structure based on a multilayer ceramic substrate. Compared to a conventional single-layer DBC substrate, the multilayer substrate structure incorporates an additional intermediate copper layer, which serves as a current return path. Due to the close proximity between this return path and the upper copper layer, the overall loop area is reduced, thereby lowering the parasitic loop inductance. Simulation results show that the designed 800 V, 50 kW SiC power module achieves a parasitic loop inductance of around 3.22 nH at 10 MHz. In addition, traditional multilayer DBC structures are typically formed by soldering two separate DBC substrates together. Such soldered interfaces are often mechanically unstable, and electrical continuity between the upper and intermediate copper layers is not established. The structure proposed in this work adopts a monolithic substrate, in which a single 300 μm thick copper layer is embedded without the use of additional solder. Compared to conventional multilayer substrates, this configuration offers improved thermal conduction by eliminating solder interfaces and enhancing heat flow.

Abstract: This study introduces a surrogate model-based optimization methodology to explore a wide design space of power module packages for achieving user-defined electromagnetic design objectives, such as minimizing commutation loop stray inductance, gate loop stray inductance and balancing mutual inductance. A half-bridge module with four parallel SiC devices per switch position is analyzed, incorporating 17 design variables across terminals and substrate dimensions. Using Sobol sampling, 4096 design variations were simulated in Ansys Q3D to train the surrogate model, enabling efficient gradient-based single- and multi-objective optimization. Results show that the proposed methodology significantly accelerates exploration in a wide design space and outperforms traditional expert-driven methods by identifying superior electromagnetic performance.

Abstract: The growing demand for sustainable alternatives to petroleum-based polymer materials has driven the development of bio-based materials. Among them, chitosan stands out as a promising biopolymer due to its biodegradability and biocompatibility. However, its hydrophilicity, causing high water absorption, limits its practical applications. In this study, tannic acid was employed as a cross-linking agent, and chitin nanofibers (ChNFs) were introduced as a reinforcing agent to enhance the properties of the chitosan-based films. The incorporation of ChNFs significantly improved the tensile stress of the films without compromising their transparency. Furthermore, the cross-linked chitosan films with ChNFs exhibited excellent UV-blocking capabilities. This highlights their potential as an alternative to conventional petroleum-based polymers.

Abstract: This research was carried out to study punch/die shear cutting of betel palm sheath. In a shear cutting experiment, shearing process parameters i.e., the moisture content of the palm sheath and the punch/die clearance were varied and investigated. Experimental results showed that both of the process parameters played an important role on the surface cracking of the palm sheath. In order to discuss the cutting characteristics of the palm sheath, a finite element method (FEM) analysis of the shear cutting was conducted. Based on simulation results with the surface cracking observed in the experiment, it was confirmed that the position of the peak maximum principal stress on the palm sheath surface varied with the punch/die clearance. Also, the position of the surface cracking was relevant to the position of the peak maximum principal stress.

Abstract: This scientific study deals with the main issues related to the process of filling inhomogeneous materials into a rectangular hopper. The article develops an algorithm for filling particles of structurally inhomogeneous materials. A micrograph of the structure of samples of inhomogeneous materials is presented. It was found that the structure of samples of heterogeneous materials consists of three layers: external, internal and impurities of various grinding aggregates. Based on microstructural analysis, the presence of particles of various shapes and sizes was justified. On the basis of which the main initial conditions for filling the package with spherical particles were described. The basic physical and mechanical properties of structurally inhomogeneous materials were studied using the obtained results. We also constructed an approximate dependence of porosity on the particle diameter of inhomogeneous materials.

Abstract: In this work, PLA/lignin composite films have been developed for packaging films. The composite films were prepared by a solution casting method. The lignin was prepared from black liquor from the paper industry, by extracting with acetic acids at 50°C. The lignin contents in PLA matrix were 0.5, 1, 3 and 5 phr. Fourier-transformed infrared spectroscopy (FTIR) analysis demonstrated similar structure of lignin precipitation when compared with the standard lignin. The addition of lignin reduced the tensile strength of PLA/lignin films, whereas the composite film at 1 phr of lignin was more elongation than neat PLA. Scanning electron microscopy (SEM) micrographs showed the roughness surface and voids in the composite films, except 1 phr and 5 phr of lignin with a better interface between PLA and lignin. UV-Vis analysis indicated reduced light transmission with increasing lignin contents in UV region.

Abstract: The NH4OH-KOH pulping was a highly efficient process for extracting banana pseudostem waste (BNW) pulp. Besides, this greener pulping process allowed NH4OH recovery and KOH can be later used as fertilizer, reducing the environmental impact. It was found that the optimal BNW pulping condition was using 8.3 wt% NH4OH and 3.3 wt% KOH at a cooking temperature of 155°C for 1 h, and liquid to solid ratio 6:1. From the results, this process allowed low chemical usage and provided high pulp yield (44%) with a high delignification degree (80%) and low Kappa no. (22). After pulping, the single-stage bleaching of BNW pulp using 8 wt% H2O2 and 1.5 wt% NaOH at 90°C for 1 h was shown to improve the whiteness and brightness of the BNW molded pulp samples to 69.7% and 28.7%ISO (3-fold increase), respectively. As compared to commercial molded pulp food packaging, the present BNW molded pulp exhibited a superior tensile index of 54.3 Nm/g and Young’s modulus of 4.8 GPa.

Abstract: Cellulose nanocrystals (CNCs) have shown remarkable application prospects due to their outstanding chemical and physical properties. In this research, cellulose nanocrystals were isolated from grass waste using alkali, bleaching and acid hydrolysis treatments and further used as nanofiller in polyvinyl alcohol (PVA) films. The valorisation of the grass waste, as an eco-friendly and sustainable low-cost precursor yields ~23.3% of CNCs. The morphology of the CNCs was observed under transmission electron microscopy and the influence of the grass waste derived CNCs (gw-CNCs) content on the optical transmittance, and water uptake and absorption capacity were investigated by varying the CNCs content in the PVA films. The results showed that the UV transmittance, and water uptake and absorption capacity of the composite films decreased with increasing of gw-CNCs content. The optimum gw-CNCs content for the composite film was determined in this study. The enhanced characteristics contributed to the UV shielding and water absorption properties implies the potential of the gw-CNCs to be used as potential nanofiller for packaging application.

Abstract: There are increasing intrest in research on corn based bioplastic to replace current plastic. However, corn based bioplastic faces a major drawback which are lack water barrier and poor mechanical properties resulting from its hydophilic properties. To produce better corn based bioplastic properties, a lot of research has been focuses on blend corn based bioplastic with other co biopolymer or additives and also radiation. By using radiation corn based bioplastic will induce degradation, cross linking or grafting and next the properties of corn based bioplastic will be improve in aspect of mechanical, physical and barrier properties and also acceptable to use as packaging material. Irradiated corn based bioplastic also have wide range of technology, the availability, less harmful to environment and the most important is the potential to use as packaging material. There is hot debate about using irradiated corn based bioplastic as packaging material. This review paper will be discussing and also to provide information on influence of radiation on the properties corn based bioplastic and its feasibility as packaging material.