Multi Material Micro Manufacture Network of Excellence - Assembly & packaging

Concept for Packaging of a Silicon based Biochip

Tue, 29 Jul 2008 16:41:15 +0100

T. Velten (a), M. Biehl (a), T. Knoll (a), W. Haberer (a)
(a) Fraunhofer Institute for Biomedical Engineering, Ensheimer Strasse 48, 66386 Sankt Ingbert, Germany

Abstract

We report on a concept for packaging of a silicon-based biochip for integration with a fluidic cartridge, thus forming a lab-on-chip (LOC). The biochip, which has dimensions of 2 mm x 2 mm, comprises a central membrane having a diameter of 200 μm, and 20 bond pads with metal tracks leading to the membrane. The packaged biochip provides a fluidic interface to the cartridge as well as electrical interfaces to the biochip electronics being located in a readout instrument. The packaging method ensures the strict separation between the wet sensing area and the electrical contacts. The challenge is that the biochip has a freely moving membrane, additionally with a delicate biological coating, and this membrane is positioned on the same side of the silicon chip as the bond pads for the electrical interconnection. For packaging, the biochip is mounted into a recess of a rigid printed circuit board (PCB). The biochip is electrically connected with the PCB using a proprietary MicroFlex interconnection (MFI) technology, thus resulting in a flat surface towards the reaction chamber of the fluid cartridge. After the realization of the electrical contacts between the sensor chip and the PCB, the entire chip is encapsulated with an epoxy layer, leaving the membrane of the biochip uncovered. To protect the membrane against the fluidic epoxy, a specially shaped silicone casting-mould is used. In a last step, the biochip with the epoxy layer is glued on the bottom side of the cartridge.

Material aspects for batch integration of PZT thin films using transfer bonding technologies – Q2M development

Tue, 29 Jul 2008 13:20:13 +0100

D. Bhattacharyya (a), R. V. Wright (a), Q. Zhang (a), P.B. Kirby (a), R. Guerre (b), U. Drechsler (b), M. Despont (b),
F. Saharil (c), J.Oberhammer (c)
(a) Materials Department, Cranfield University, Bedford MK43 0AL, UK
(b) IBM Research Gmbh, Zurich Research Laboratory, Rueschlikon, Switzerland
(c) Microsystem Technology Lab, KTH – Royal Institute of Technology, Stockholm, Sweden

Abstract

Transfer bonding is a reliable cost-efficient and low-temperature CMOS compatible technique which allows batch integration of materials whose incompatibility with Si makes them unsuitable for monolithic integration. In this heterogeneous device integration method the material and process incompatibilities inherent in Si IC technology are overcome by fabricating devices on separate substrates and then transferring them onto target (e.g. CMOS) wafers. Transfer bonding has great potential for integrating RF-MEMS devices incorporating, for example, high thermal budget materials such as PZT and PST or non-ferroelectric piezoelectrics such as AlN and ZnO into microwave ICs for enhanced systems performance. This paper presents an overview of technology developments within the EU sponsored project Q2M for the realization of transfer bonded piezoelectrically actuated RF MEMS switches and other components focusing in particular on material factors relating to growth of the piezoelectric films, in this case sol-gel deposited PZT, that restricts the choice of device layers and impact on PZT properties such as microstructure, film orientation and piezoelectric coefficients. New process developments such as hard masking of PZT pattern during RIE etching and its compatibility with polymer transfer bonding are discussed.

Wafer-scale manufacturing of robust trimorph bulk SMA microactuators

Tue, 29 Jul 2008 13:01:00 +0100

N. Sandström (a), S. Braun (a), T. Grund (b), G. Stemme (a), M. Kohl (b), W. van der Wijngaart (a)
a Microsystem Technology Lab, KTH - Royal Institute of Technology, Stockholm, SWEDEN
b Institut für Mikrostrukturtechnik, Forschungszentrum Karlsruhe GmbH, Karlsruhe, GERMANY

Abstract

This paper demonstrates the concept of wafer-level fabrication and integration of robust bulk SMA microactuators based on adhesive bonding of cold-rolled SMA sheets to silicon wafers. Contact printing of an adhesive polymer ensures a selective bonding when transferring full SMA sheets to silicon structures on a patterned wafer. The induced stress of a thin dielectric film deposited on top of the SMA sheet ensures a stable and built-in reset mechanism of the actuators. The trimorph microactuators can be actuated by indirect resistive heating through a thin metal film. We report on the successful wafer-scale fabrication of actuator cantilevers and their characteristics. First test cantilevers show a cold-state deflection of 300 μm which, however, is limited by the silicon substrate. Upon heating, the cantilever shows a stroke of approx. 80 μm.

Batch Fabrication Methods for Polymer Based Active Microsystems using Hot Embossing and Transfer Bonding Technologies

Tue, 29 Jul 2008 12:51:28 +0100

T. Grund, M. Heckele and M. Kohl
Forschungszentrum Karlsruhe GmbH, Institute for Microstructure Technology (IMT),Postfach 3640, 76021 Karlsruhe, Germany

Abstract

A batch compatible process flow to overcome the costly piece by piece assembly of hybrid microsystems is shown. Hot embossing is used to fabricate microstructured polymer layers. Wafer scale compatible bonding tasks are carried out by ultrasonic welding and heat activated bonding with micromachined bonding foils. As demonstrator device, a shape memory alloy (SMA) actuated polymer microvalve is introduced. The valve concept, fabrication technologies and device characteristics are discussed.

The integration of mono-crystalline silicon micro-mirrors on CMOS for SLM applications

Tue, 29 Jul 2008 12:33:53 +0100

F. Zimmera, M. Friedrichsa, M. Lapisac, F. Niklausc, M. Muellera, T. Bakkeb, H. Schenka, H. Laknera
a Fraunhofer Institute for Photonic Microsystems (IPMS), Maria-Reiche-Str. 2, D-01109 Dresden, Germany
b SINTEF Department of Mikrosystems and Nanotechnology, Gaustadalleen 23C, Oslo, Norway
c KTH, The Royal Institute of Technology, Stockholm, Sweden

Abstract

Spatial light modulators (SLMs) based on micro-mirrors for use in DUV lithography and adaptive optics need very high mirror planarity as well as mirror stability. We will present results of new micro-mirror arrays, consisting of monocrystalline silicon, which is a material to fulfil these requirements. As all mirrors of the SLM can be separately activated by an underlying CMOS circuit, the integration of CMOS and MEMS must be achieved, which results in certain restrictions on processing temperatures and the compatibility of materials. Therefore a special low temperature bonding technology has been developed, using an adhesive polymer. This technique provides the transfer of a 300nm thin mono-crystalline silicon layer to the CMOS wafer using only 250°C. First silicon micro-mirrors have been made and characterized using pure adhesive polymer (PMGI), improvements using a mix of an inorganic material with a thin bond-polymer benzocyclobutene BCB) on top are in development. Both approaches and their results will be discussed and presented in detail.

Engineered Self-assembly From Nano to Milli Scales

Tue, 29 Jul 2008 12:19:40 +0100

Karl F. Böhringer
Department of Electrical Engineering, University of Washington, Seattle, WA 98195-2500, USA

Abstract

Self-assembly is the autonomous and spontaneous organization of components into patterns or structures. Self-assembly is ubiquitous in nature, e.g. in the growth of crystals and organisms, but also at macroscopic scales – it is nature’s prevalent paradigm for manufacturing. Self-assembly also provides the basis for important new industrial manufacturing techniques, especially for components at the milli, micro, and nano scales: their small sizes and large numbers scale unfavorably for common serial techniques but favorably for a new, massively parallel approach. We believe that self-assembling systems will be able to create complex, heterogeneous, non-periodic, three-dimensional
devices in massively parallel production processes. Hence, our research investigates the scientific and engineering foundations of self-assembly processes for integrated micro/nanoelectromechanical systems (MEMS/NEMS).

Innovative handling techniques of thin flexible micro parts

Tue, 20 May 2008 13:54:13 +0100

C. Brecher, C. Peschke, S. Lange
Fraunhofer Institute for Production Technology IPT, Aachen, Germany

Abstract

Assembly of hybrid micro systems is still done manually in many cases. This strategy is very time consuming and not sufficient in its repeatability and positioning accuracy. This disadvantage especially constrains the assembly of micro optical systems such as fiber couplers. Assembly accuracies in the micro or even sub-micrometer range are often needed. With this background the Fraunhofer IPT is optimizing gripper structures, gripper materials or gripping parameters especially for the handling of flexible micro parts such as glass fibers. The aim is to detect the influences on the reproducible positioning in the gripper. An optimized gripper design and best suited gripping parameters can be derived by this basic research. Another aim is to design and implement a completely new adaptive gripper concept for the handling of flexible micro parts. This system is equipped with an integrated highly robust and cost-effective positioning system that allows adjustment in the sub-micrometer range. This gripper can be adapted to common robots to conduct micro assembly operations. The robot can be used for high-speed pre-positioning. The necessary assembly accuracies are achieved directly at the tip of the gripper by using its integrated axis-system.

High aspect ratio micron-sized vias in "flex" and polymer foils using ion irradiation

Mon, 19 May 2008 15:21:11 +0100

H. Yousef, M. Lindeberg, K. Hjort
Department of Engineering Sciences, Uppsala University, Box 534, 75121 Uppsala, Sweden

Abstract

As the call for higher wiring density in packaging and interconnection technologies rapidly evolves, the need for smaller dimensions in vias and interconnects must be met. The frontier of advanced high aspect ratio technologies is today often found within microelectronics and MEMS. The process described in this paper stems from advanced MEMS and allows micromachining of deep, vertical vias in polyimide based foils and flexible-PCBs. The process is superior with respect via throughput and size compared with traditional via manufacturing techniques such as chemical etching, drilling, dry etching and laser ablation.

The technique makes use of ion irradiation to enhance the selectivity and directionality of the chemical etching technique. Within the areas exposed to the ion irradiation, small sub-micron pores (capillaries) are created, one for every ion. If etching is prolonged, the pores become merged. Conventional electrodeposition from a metallic seed layer is used to fill these structures with metal. The smallest achievable size of the vias is only limited by the resolution of the mask; vias of below 10 μm in diameter can readily be achieved in a 75 μm thick polyimide foil. It is possible to obtain two inherently different types of via structures using this process: (1) conventional solid vias, and (2) vias consisting of bundles of sub-micron wires (having a specified metal density between 0.2 and 20%). As the individual sub-micron wires have aspect ratios of several hundreds, this allows fabrication of truly vertical via structures, allowing ultra high-density wiring.

Fabrication Chain for Prototyping of Microfluidic Chips in Polymers

Mon, 19 May 2008 15:09:50 +0100

T. Brenner, C. Müller, H. Reinecke, R. Zengerle, and J. Ducrée
IMTEK – University of Freiburg, Georges-Koehler-Allee 106, D-79110 Freiburg, Germany

Abstract

We established an integrated prototyping chain for rapid fabrication of microfluidic chips in polymers comprising fabrication of masters made from elastomers, replication into polymers by soft embossing, surface modification and thermal sealing. Our techniques enable rapid and precise fabrication of fully functionalized microfluidic chips featuring typical minimum lateral dimensions of 50 μm and aspect ratios smaller than one.

Micro Assembly Injection Moulding Potential Application in Medical Science

Mon, 19 May 2008 13:46:17 +0100

Prof. Dr.-Ing. Dr.-Ing. E.h. Walter Michaeli, Dipl.-Ing. Dirk Opfermann
Institute of Plastics Processing (IKV) at RWTH Aachen University, 52062 Aachen, Germany

Abstract

The miniaturisation of technical products becomes more important in many technological areas. Many functions can be optimised by the use of micro systems. On less space more functions can be integrated. In the field of medical technology miniaturisation means also new methods of treatment with fewer side effects on the patient. New cures are being developed as a result of the miniaturisation of medical instruments, such as the key hole surgery. Polymers are spread widely in the field of medical applications. Since plastics are a relatively cheap material and polymer parts can easily be reproduced in high series and accuracy, for examples by injection moulding, their use as disposable articles is predetermined. Polymer materials offer a wide range of properties that can be chosen according to the functional necessities.

A New Approach to Qualitiy Assurance in Resistance Welding for Microsensors Packaging

Mon, 12 Nov 2007 16:23:32 +0000

D. Ulieru(a), Alina Matei(b), Elena Ulieru(c), A. Tantau(c)
a: ROMES S.A., 126A, Iancu Nicolae Str., Bucharest, 72996, Romania
b: National Institute for Research and Development in Microtechnologies, 32B, Erou Iancu Nicolae Str., Bucharest, 077190, Romania
c: SITEX 45 SRL, 114, Ghica Tei Blvd., bl. 40, ap. 2, Dept. 2, Bucharest 72235, Romania

Abstract

The permanent development of microelectronics technologies provide new challenges for miniaturization and complexity increasing for new packaging technologies. So the exciting applications for microsystems, sensors and actuators production are looking for the best quality hermetic sealing of metal packages. The paper showed our researches and experiments results for a new approach to quality assurance in resistance welding. These will analyze the main causes of weld failures and also our methods of determining its value. On the basis of this requirement have monitored through the weld sequence, integrated concept of power monitor. The technical features developed a modern concept applicable to a wider range of fields. Our monitor could be used to wide range of welding technologies like distributed spot and focused spot, projection, roller spot and mash welding machines, working with single or three phase, ac. or dc. The experiments with our equipment have proven its advantage for fast production assembly line.

Laser Transmission Welding of Transparent Plastics Parts in Micro Technology

Mon, 12 Nov 2007 16:23:32 +0000

E. Haberstroh, W.-M. Hoffmann
Institute of Plastics Processing (IKV), RWTH Aachen University, 52056 Aachen, Germany

Abstract

Most welding processes for plastics do not meet the special demands of micro technology. Laser transmission welding, however, features distinctive advantages like low mechanical and thermal load of the joining parts. Hence it is particularly suitable for the welding of micro plastics parts. Certain optical properties of the components to be welded are needed though. While one of the welding parts has to exhibit a high transmittance in the range of the laser wavelength the absorptance of the other one has to be high enough to ensure a sufficient absorption of the laser radiation to plasticise the material. Here, carbon black has almost exclusively gained industrial importance, since it is an inexpensive material with good absorbing properties. However, it leads to a black coloration which is not always acceptable. Recently, there are special pigmentations which allow for a non black colour in the visible range of light, but nevertheless absorb laser radiation. Up to know, only few is known about their welding characteristics, so that it has to be investigated whether they are suitable for the application in micro technology.

New Methods for Selective Metallization of 3-D Polymer Microparts

Mon, 12 Nov 2007 16:23:32 +0000

R.A. Tacken, R. de Zwart, H. Rendering, P.J. Bolt
TNO Science and Industry, Eindhoven, The Netherlands

Abstract

The development of microdevices would be well served by integration of electronic connects into 3-D packaging. A number of technologies have been proposed in which conductive paths are created on polymer structures, e.g. by local activation of organometallic components present in plastic. But these suffer either from limited 3-D freedom, yield problems in mass production or excessive use of chemicals. Here two new and patented methods, selective etching and selective masking, for selective metallization for the production of three dimensional integrated devices are presented, which do not use precatalyzed polymers. After initial tests, a two-shot moulded three-dimensional test object with solder patches, through holes and varying track widths was used to test their selectivity and reproducibility for selected polymer combinations. The selective etching method gave for the PA4,6-PET combination excellent results with regard to the selective plating and subsequent reflow soldering. The second method, selective masking could be applied to a LCP-PPS combination, however process stability needs to be improved.

High Precision Placement of Solar Cell Assemblies on Large Base Plates for Concentrator Photovoltaics

Mon, 12 Nov 2007 16:23:32 +0000

J. Jaus(a), A.W. Bett(a), H. Reinecke(b), E.R. Weber(a)
a: Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstr. 2, 79110 Freiburg, Germany
b: IMTEK, University of Freiburg, Georges-Köhler-Allee 103, 79110 Freiburg, Germany

Abstract

Photovoltaic concentrator applications use an optical system to concentrate sunlight on solar cells. A high concentration factor is necessary in order to reduce the size of the solar cells and hence to lower the costs for concentrator systems. The precise handling of the small solar cells calls for a high precision micro assembly process for base plate manufacturing. In this paper, the accuracies of the equipment and the processes used for high precision assembly of module base plates are analyzed. The sensitivity of the concentrator module to lateral dislocations of the cells is investigated in order to quantify the accuracy needed for the assembly process. The manufacturing equipment was characterized with respect to repeatability and to absolute accuracy. A repeatability of ± 6 μm for the X-axis and ± 15 μm for the Y-axis has been determined. The process accuracy is better than ± 60 μm, depending strongly on the measurement methods used for calculating the position errors.

ASSEMIC: Research Advances in Microhandling and Assembly – “Special ASSEMIC Session”

Mon, 12 Nov 2007 16:23:32 +0000

Ana Almansa(a), S. Bou(a), Z. Rozynek(a) , W. Brenner(b)
a: Profactor R&S GmbH, Seibersdorf 2444, Austria
b: TU Wien – ISAS, Floragasse 7/2, Vienna 1040, Austria

Abstract

Few technical fields are so multidisciplinary and present so challenging demands as microtechnologies. The Research and Training Network “Advanced Methods and Tools for Handling and Assembly in Microtechnology” (ASSEMIC) addresses this research field at a European scale. ASSEMIC brings together a consortium of 14 participants, focusing their efforts in microhandling and microassembly. This paper summarizes some of the latest results achieved in this project.