Microcomponents Assembly in Liquid Environment – LEMA

To reach this goal, we propose an approach whose originalities may be stated as follows:
1. We clearly identify a dimensional no man’s land ranging from 0.1 to 10µm (typical dimension of the microcomponents), i.e. between the well-known bottom up techniques coming from the chemistry and the
miniaturization efforts of the robotic industry;
2. We address the lack of techniques in that domain not focusing on a very sharp technique but targeting the integration of many techniques in a new micro-assembly toolbox. This toolbox will be developed according
to a functional description of assembly: feeding the components to assemble, aligning and positioning them and finally joining them;
3. Each function will be studied from a novel perspective: feeding will be achieved in microfluidic system used as conveyor, aligning and positioning will be done with magnetic and electrostatic forces fields, including the most advanced techniques for control of the trajectories, and finally, proposing a quantitative comparison of a series of joining techniques based on bio-inspired and chemical bondings.

During the last ten years, microhandling solution dedicated to micro-object whose size is around 50 micrometers have been developed in academic institutes and is currently under transfer in industry for scientific instrumentation market (Percipio-Robotics – startup of FEMTO-ST) or packaging of 3D-STACK microelectronic components (NXP, ST microelectronics) or assembly of optical microsystems (Beam Express). These works have shown the ability to the French micronanorobotic community to work upstream from the industrial demand in order to build future generation of micronanomanufacturing industries based on
international technical innovation.

The industrial problem this projects aims at contributing to is the (micro)assembly of heterogeneous micron-scale components. In our vision, these latter are miniaturized products embedding micron-size functions, whose proof-of-concepts have been demonstrated by the recent advances in nanotechnology, such as chemical, biomedical or environmental nanosensors. This kind of products may only come to the market if they are firstly proven to be better than existing solutions, and this can only be done if they can be packaged with adequate reliability at an adequate cost. To this aim, we intend to develop new transfer, positioning and joining methods constituting a new assembly toolbox, proposing different solutions to achieve each function. Despite the large number of strong scientific works in nanotechnology, related miniaturized electromechanical systems hardly come to the market. Even if there is no unique explanation for this, we believe that improving assembly systems in the micron-size will help to this breakthrough.

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This project deals with micro-assembly in the mesoscale between micro and nanoscales, which comprises objects whose size is from 100nm to 10µm. It addresses several scientific problematics, in the domains of microfluidics, micro-nanorobotics and nanojoining. This topic presents an applicative interest for next generation of nanotechnological components. Indeed, despite a large number of proofs of concept of elementary functions (e.g. chemical, biomedical or environmental sensors) in nanotechnologies, related nano electromechanical systems (NEMS) hardly come to the market. One of the bottlenecks is the packaging of these new components whose dimensions are around the micrometer. As for micro electromechanical systems (MEMS) where packaging is based on robotic microhandling, the packaging of NEMS requires to be able to handle, position and join components together. Current industrial state of the art is limited to the assembly of hundred microns scale dies which is inappropriate for nanotechnologies which is able to provide components hundred times smaller. This project will provide innovative methods to perform assembly of components in the mesoscale between micro and nanoscales in order to open new ways in packaging for nanotechnologies.

In a scientific point of view, mesoscale represents a paradigm in assembly methods : this mesoscale assembly is situated between nanoscale and microscale assembly, which are two completely different processes. On the one hand, self-assemblies (chemical reactions) have been used for decades to build assembled nanocomponents. On the other hand, microassemblies in industry are mainly based on robotic handling and positioning. Mesoscale represents a crossroad between these two approaches, where scientific studies are required to provide ad hoc solutions for this particular scale.

We propose to study some hybrid approaches based on directed self-assembly, which is based on physical effects (non- contact forces) usually used in self-assembly, but also on active trajectory control inspired from robotics. As self-assembly is mostly performed in liquid, we will perform directed self-assembly in liquid channels, also used to convey components. Objects will be positioned by non contact forces, and joined with original nanojoigning methods. Consequently this project is divided in three technical workpackages respectively on (i) the study of fluidic transfer of mesoscaled objects in microchannels; (ii) the study of objects positioning based on non-contact forces and (iii) the study of ad hoc nanojoining methods. These methodologies will be implemented in a final demonstrator in the fourth workpackage. A special attention will be paid to the management of the project in a last workpackage.
The methods developed in the project will enable the assembly of mesoscale objects into stacks, to get different sensing capabilities integrated into the same component. They will also provide original ways to realize wire connection at the mesoscale. This project thus directly addresses the main issues of nanopackaging.

This project relies on the internationally recognized partners. FEMTO-ST in Besançon and ISIR in Paris have top level expertise in micro-assembly and non-contact micromanipulation. They have successfully collaborated in the previous years on several ANR projects (ANR PRONOMIA, ANR NANOROL, EQUIPEX ROBOTEX). This consortium also includes the LOF which has a strong knowledge and international expertise in microfluidic. This multidisciplinary consortium has been built to tackle the complex scientific challenges proposed in this project.

This project will provide new assembly methodologies in mesoscale in the framework of nanotechnology packaging. It is a first crucial step in the advent of industrial assembly methods in mesoscale which could be followed by a more applicative project supported by ‘ANR Emergence framework’ in order to prepare the transfer in the two years following this project.