Modeling, Simulation, and Experimentation of a Promising New Packaging Technology: Parallel Fluidic Self‐Assembly of Microdevices (original) (raw)
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Concept for Fluidic Self-Assembly of Micro-Parts Using Electro-Static Forces
Self-assembly is relatively unused in industrial micro-fabrication, although it offers opportunities to simplify processes and to lower manufacturing costs. A variety of self-assembly procedures have been introduced that take advantage of various forces, e.g. capillary, gravitational, electro-static. In this paper a concept for the alignment of micro-parts on a substrate using fluidic-self-assembly with electro-static attraction is presented. Further, FEM-simulations for the electro-static alignment force are performed and its dependence on several geometric parameters, e.g. the width of the binding sites and the distance between micro-part and substrate at the binding sites, is investigated. Based on results an analytic model is extracted. Furthermore, simulations are also performed to estimate capillary alignment forces, acting on micro-parts that are self-aligned. Finally, the magnitude of electro-static and capillary forces is compared. This novel assembly concept, where the ali...
Multi-batch micro-self-assembly via controlled capillary forces
… and Systems, 2001. …, 2001
Recent advances in silicon processing and microelectromechanical systems (MEMS) have made possible the production of very large numbers of very small components at very low cost in massively parallel batches. Assembly, in contrast, remains a mostly serial (i.e., nonbatch) technique. In this paper, we argue that massively parallel selfassembly of microparts will be a crucial enabling technology for future complex microsystems. As a specific approach, we present a technique for assembly of multiple batches of microparts based on capillary forces and controlled modulation of surface hydrophobicity. We derive a simplified model that gives rise to geometric algorithms for predicting assembly forces and for guiding the design optimization of selfassembling microparts. Promising initial results from theory and experiments and challenging open problems are presented to lay a foundation for general models and algorithms for selfassembly.
Self-assembly of microsystem components with micrometer gluing pads through capillary forces
Journal of Manufacturing Processes, 2020
The self-alignment of microparts based on capillary forces and micrometer adhesive pads was evaluated through experimental evidence, analytical modelling and simulation. The local deposition of adhesive pads in the range of 2000 to 20 μm was realized by photo-lithographical patterning of an acrylate adhesive interlayer, followed by the spontaneous assembly with glass counterfaces that have a complementary array of hydrophobically modified gold structures. The design rules for self-alignment of microparts were studied from calculations of the capillary force and displacement as a function of the adhesive pad dimensions, pad heights and offset length. In all cases, the self-alignment induced by capillary forces is driven by a minimization of the surface energy, leading to an equilibrium position. The analytical results provided good qualitative understanding of the alignment process: larger dimensions, smaller separation and higher offset values contributed to higher forces and fast alignment. The simulation experiments in Surface Evolver were based on calculated geometries of adhesive pad providing a minimum surface energy and also take into account the local deformation of the adhesive pad together with an additional degree of rotational freedom. Consequently, the latter results indicated a high degree of precision with good correlation to the experiments and analytical results.
2010 IEEE 23rd International Conference on Micro Electro Mechanical Systems (MEMS), 2010
This paper presents a novel method to achieve high yield assembly of millimeter-scale thin silicon chips from an air-water interface. Surface functionalized silicon parts (1000!1000!100 !m 3 ) assemble in preprogrammed hydrophilic locations on a wafer substrate with self-alignment. We optimized the process and design factors systematically using DOE (Design of Experiment) that leads to high yield (100 %).
Precision Engineering
Self-assembly of components using liquid surface tension is an attractive alternative to traditional robotic pick-and-place as it offers high assembly accuracy for coarse initial part placement. One of the key requirements of this method is the containment of the liquid within a designated binding site. This paper looks to expand the applications of self-assembly and investigates the use of topographical structures applied to 3D printed micro components for self-assembly using liquid surface tension. An analysis of the effect of edge geometry on liquid contact angle was conducted. A range of binding sites were produced with varying edge geometries, 45-135°, and for a variety of site shapes and sizes, 0.4 - 1 mm in diameter, and 0.5 × 0.5–1 × 1 mm square. Liquid water droplets were applied to the structures and contact angles measured. Significant increases in contact angle were observed, up to 158°, compared to 70° for droplets on planar surfaces, demonstrating the ability of these ...
Challenges for capillary self-assembly of microsystems
2011
Within the currently rising trend of heterogeneous microsystem integration and packaging, capillary self-assembly emerges as an innovative technique to enhance, complement and eventually replace pick-and-place assembly. Vast literature and experimental data support such claim. Still, the technique needs to overcome some important limitations in order to fully express its potential and earn wide industrial recognition. In this paper, we review and illustrate what are in our opinion the challenges ahead for making part-to-substrate capillary self-assembly reliable and seriously competitive with long-established assembly techniques. After setting self-assembly methods in the context of microsystem assembly and integration technologies, we focus on the standard embodiment of capillary self-assembly, and we describe in details the main, often novel technological steps required for its effective and reproducible performance. This preludes to an outline of what are presently, in our view, the major failure modes affecting the overall yield of the capillary self-assembly technique. Consequently, we propose solutions to face and overcome these challenges, which need to be met to foster the success of this technique.
Processes for the Self-assembly of Micro Parts
IFIP Advances in Information and Communication Technology, 2012
The following approach of a fluidic based self-assembly process uses the surface forces for a precise handling and positioning of small devices for a roll-to-roll manufacturing. The surface, on which the device should be positioned, will be functionalized with hydrophile and hydrophobic areas. Thus water droplets can be caught on the hydrophile areas. The devices to be positioned will be placed on these droplets and due to the surface tension moved to their final position. The droplets, a solution of ultrapure water and isopropanol, are evaporating residue-free within seconds [1].
Part tilting in capillary-based self-assembly: Modeling and correction methods
2008 IEEE 21st International Conference on Micro Electro Mechanical Systems, 2008
We present a model and experimental results on tilt angle of microparts in capillary-driven self-assembly. The assembly is carried out in an aqueous environment, using a heat curable adhesive for part-substrate lubrication and mechanical bonding. Silicon parts and substrate have matching hydrophobic binding sites, which drive the assembly by surface energy minimization. Force balance analysis of an assembled part leads to a model describing the dependence of tilt angle on assembly parameters such as adhesive volume and water-adhesive interfacial tension. The effect of adhesive volume on tilt angle is investigated experimentally. Tilt correction of the assembled parts is achieved by providing external energy to the system via vertical vibration.