Selected Papers from the 24th EuroSimE Conference

A special issue of Micromachines (ISSN 2072-666X). This special issue belongs to the section "A:Physics".

Deadline for manuscript submissions: closed (30 September 2023) | Viewed by 2907

Special Issue Editors

Academy for Engineering & Technology, Fudan University, Shanghai 200433, China
Interests: LED packaging and system integration; prognostics and health management; wide bandgap power electronics packaging and reliability modeling
Special Issues, Collections and Topics in MDPI journals
Dr. Véronique Rochus
E-Mail Website
Guest Editor
Sensor and Actuator Technology Department, IMEC, Kapeldreef 75, B-3001 Leuven, Belgium
Interests: MEMS; electromechanical coupling; multiphysics; FEM

Special Issue Information

Dear Colleagues,

On behalf of the Editorial Board, we are pleased to propose a selection of papers presented at the 24th International Conference on Thermal, Mechanical and Multiphysics Simulation and Experiments in Microelectronics and Microsystems (EurosimE 2023) held in the city of Graz, Austria, April 16-17-18-19, 2023 (https://www.eurosime.org/). EuroSimE was created as the only annual international conference focusing on thermal, mechanical and multiphysical simulations and experiments for microelectronics and microsystems. The first conference was initiated in 2000 by the COMPETE network, with sponsorship from the European Commission, to meet research and development needs in microelectronics and microsystems. Since then, EuroSimE has garnered worldwide attention with participants from more than 30 countries, spanning all continents, and has become a fully sponsored IEEE CPMT technical event. The EuroSimE conference has earned a reputation for high scientific and technical quality. We hope that this Special Issue will be helpful to your work. We also welcome your feedback and suggestions for improving our work to provide you with valuable references in the future. We would also like to sincerely thank the journal Micromachines for its editorial support and constant assistance throughout the preparation of this issue.

Dr. Jiajie Fan
Dr. Véronique Rochus
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Micromachines is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • MEMS/NEMS
  • microelectronics
  • microsystems
  • reliability
  • simulation and modeling

Published Papers (3 papers)

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Research

13 pages, 9519 KiB  
Article
Bond Wire Fatigue of Au, Cu, and PCC in Power LED Packages
Micromachines 2023, 14(11), 2002; https://doi.org/10.3390/mi14112002 - 28 Oct 2023
Viewed by 707
Abstract
Bond wire failure, primarily wire neck breakage, in power LED devices due to thermomechanical fatigue is one of the main reliability issues in power LED devices. Currently, the standard testing methods to evaluate the device’s lifetime involve time-consuming thermal cycling or thermal shock [...] Read more.
Bond wire failure, primarily wire neck breakage, in power LED devices due to thermomechanical fatigue is one of the main reliability issues in power LED devices. Currently, the standard testing methods to evaluate the device’s lifetime involve time-consuming thermal cycling or thermal shock tests. While numerical or simulation methods are used as convenient and quick alternatives, obtaining data from material lifetime models with accurate reliability and without experimental fatigue has proven challenging. To address this issue, a mechanical fatigue testing system was developed with the purpose of inducing mechanical stresses in the critical region of the bond wire connection above the ball bond. The aim was to accelerate fatigue cracks at this bottleneck, inducing a similar failure mode as observed during thermal tests. Experimental investigations were conducted on Au, Cu, and Pd-coated Cu bonding wires, each with a diameter of 25 µm, using both low- and high-frequency excitation. The lifetime of the wire bond obtained from these tests ranged from 100 to 1,000,000 cycles. This proposed testing method offers material lifetime data in a significantly shorter timeframe and requires minimal sample preparation. Additionally, finite element simulations were performed to quantify the stresses at the wire neck, facilitating comparisons to conventional testing methods, fatigue test results under various operating conditions, material models, and design evaluations of the fine wire bond reliability in LED and microelectronic packages. Full article
(This article belongs to the Special Issue Selected Papers from the 24th EuroSimE Conference)
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23 pages, 13456 KiB  
Article
Capillary Underfill Flow Simulation as a Design Tool for Flow-Optimized Encapsulation in Heterogenous Integration
Micromachines 2023, 14(10), 1885; https://doi.org/10.3390/mi14101885 - 30 Sep 2023
Viewed by 1085
Abstract
As the power electronics landscape evolves, pushing for greater vertical integration, capillary underfilling is considered a versatile encapsulation technique suited for iterative development cycles of innovative integration concepts. Since a defect-free application is critical, this study proposes a capillary two-phase flow simulation, predicting [...] Read more.
As the power electronics landscape evolves, pushing for greater vertical integration, capillary underfilling is considered a versatile encapsulation technique suited for iterative development cycles of innovative integration concepts. Since a defect-free application is critical, this study proposes a capillary two-phase flow simulation, predicting both the flow pattern and velocity with remarkable precision and efficiency. In a preliminary performance evaluation, Volume of Fluid (VOF) outperforms the Level-Set method in terms of accuracy and computation time. Strategies like HRIC blending, artificial viscosity, and implicit Multi-Stepping prove effective in optimizing the numerical VOF scheme. Digital mapping using physical experiments and virtual simulations validates transient flow predictions, achieving excellent agreement with deviations as low as 1.48–3.34%. The accuracy of flow predictions is thereby greatly influenced by non-Newtonian viscosity characteristics in the low shear range and time-dependent contact angle variations. The study further explores flow manipulation concepts, focusing on local flow speed adjustment, gap segmentation, and the use of arcuate shapes to influence interface confluence near the chip. Experimental validation corroborates the effectiveness of each design intervention. In conclusion, this research highlights the potential of predictive engineering to develop flow-optimized package designs that enhance reliability while supporting high manufacturing yields. Full article
(This article belongs to the Special Issue Selected Papers from the 24th EuroSimE Conference)
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22 pages, 2036 KiB  
Article
Simplified Phenomenological Model for Ferroelectric Micro-Actuator
Micromachines 2023, 14(7), 1355; https://doi.org/10.3390/mi14071355 - 30 Jun 2023
Cited by 1 | Viewed by 705
Abstract
As smart structures are becoming increasingly ubiquitous in our daily life, the need for efficient modeling electromechanical coupling devices is also rapidly advancing. Smart structures are often made of piezoelectric materials such as lead zirconate titanate (PZT), which exhibits strong nonlinear behavior known [...] Read more.
As smart structures are becoming increasingly ubiquitous in our daily life, the need for efficient modeling electromechanical coupling devices is also rapidly advancing. Smart structures are often made of piezoelectric materials such as lead zirconate titanate (PZT), which exhibits strong nonlinear behavior known as hysteresis effect under a large applied electric field. There have been numerous modeling techniques that are able to capture such an effect; some techniques are suitable for obtaining physical insights into the micro-structure of the material, while other techniques are better-suited to practical structural analyses. In this paper, we aim to achieve the latter. We propose a simplified phenomenological macroscopic model of a nonlinear ferroelectric actuator. The assumption is based on the direct relation between the irreversible strain and irreversible electric field, and the consequently irreversible polarization. The proposed model is then implemented in a finite element framework, in which the main features such as local return mapping and the tangent moduli are derived. The outcomes of the model are compared and validated with experimental data. Therefore, the development presented in this paper can be a useful tool for the modeling of nonlinear ferroelectric actuators. Full article
(This article belongs to the Special Issue Selected Papers from the 24th EuroSimE Conference)
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