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A low-cost, low-temperature packaging concept is proposed for localized sealing and control of the ambient of a device cavity appropriate for Radio-Frequency (RF) Micro- Electro-Mechanical (MEMS) devices, such as resonators and switches. These devices require application specific packaging to facilitate their integration, provide protection from the environment, and control interactions with other circuitry. In order to integrate these devices into standard integrated circuit (IC) process flows and minimize damage due to post-fabrication steps, packaging is performed at the wafer level. In this work Indium and Silver are used to seal a monolithic localized hermetic pack- age. The cavity protecting the device is formed using standard lithography-based processing techniques. Metal walls are built up from the substrate and encapsulated by a glass or silicon lid to create a monolithic micro-hermetic package surrounding a predefined RF microsystem. The bond for the seal is then formed by rapid alloying of Indium and Silver using a temperature greater than that of the melting point of Indium. This ensures that the seal formed can subsequently function at temperatures higher than the melting temperature of pure Indium. This method offers a low-temperature bonding technique with thermal robustness suitable for wafer-level process integration. The ultimate goal is to create a seal in a vacuum environment. In this dissertation, design trade-offs made in wafer-level packaging are explained using thermo-mechanical stress and electrical performance simulations. Prototype passive microwave circuits are packaged using the developed packaging process and the performance of the fabricated circuits before and after packaging is analyzed. The effect of the package on coplanar waveguide structures are characterized by measuring scattering parameters and models are developed as a design tool for wafer-level package integration. The small scale of the localized package is expected to provide greater reliability over conventional full chip packages. / Ph. D.

Submitted by Gabriela Lopes (gmachadolopesufpel@gmail.com) on 2018-07-17T18:43:22Z No. of bitstreams: 1 Dissertação André Capilheira pós defesa.pdf: 800960 bytes, checksum: 776bae866c79a3b55b3dd16f9cb0751c (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2018-07-17T21:41:26Z (GMT) No. of bitstreams: 1 Dissertação André Capilheira pós defesa.pdf: 800960 bytes, checksum: 776bae866c79a3b55b3dd16f9cb0751c (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2018-07-17T21:43:36Z (GMT) No. of bitstreams: 1 Dissertação André Capilheira pós defesa.pdf: 800960 bytes, checksum: 776bae866c79a3b55b3dd16f9cb0751c (MD5) / Made available in DSpace on 2018-07-17T21:48:58Z (GMT). No. of bitstreams: 1 Dissertação André Capilheira pós defesa.pdf: 800960 bytes, checksum: 776bae866c79a3b55b3dd16f9cb0751c (MD5) Previous issue date: 2016-09-06 / As características dos materiais utilizados nas embalagens para armazenamento de sementes podem influenciar negativamente no processo de deterioração, acarretando problemas futuros no período de armazenamento e na emergência em campo. Desta forma, objetivou-se avaliar a qualidade fisiológica de sementes de soja, armazenadas em embalagens permeável e hermética e mantidas em condições ambientais não controladas. Para a realização do experimento foi utilizado um lote de sementes de soja da cultivar SYN 1059 RR. Foi empregado quatro repetições, distribuídas em parcela dividida 3x6 (três tipos de embalagens x seis períodos de armazenamento). Foram utilizadas embalagens de papel multifoliado, hermética e hermética com injeção de CO2, armazenadas por 225 dias e avaliação em intervalos regulares de 45 dias. Após o ensaque das sementes de soja, foi avaliada a qualidade das sementes através das análises de germinação, envelhecimento acelerado, umidade, condutividade elétrica e emergência em campo. A embalagem hermética, com e sem injeção de CO2, favorece a diminuição da velocidade da deterioração das sementes de soja. A embalagem hermética permite uma maior qualidade fisiológica das sementes de soja comparativamente à embalagem permeável, no período de armazenamento até 180 dias sobre as condições ambientais não controladas. / The characteristics of materials used in packages for seeds storage may negatively influence in the deterioration process, causing future problems in the period of storage and in the emergence in the field. Thus, we aimed to assess the physiological quality of soya beans, stored in permeable and hermetic packages and stored in uncontrolled environmental conditions. In order to carry out the experiment, we used a soya beans lot from the cultivar SYN 1059 RR. It was used four repetitions, distributed in divided portion 3x6 (three types of packages x six storage periods). We used multi-wall paper, hermetic and hermetic with CO2 injection packages, stored for 225 days and an assessment of regular intervals of 45 days. After bagging the soya beans, the beans quality was assessed through the analysis of germination, accelerated aging, humidity, electric conductivity and emergence in the field. The hermetic package, with and without CO2 injection, favors to reduce the speed of deterioration of soy bean seeds. The hermetic package allows a higher physiological quality of soya beans comparatively to the permeable package, in the storage period of up to 180 days under uncontrolled environmental conditions.

Radio-frequency microelectromechanical systems (RF~MEMS) are highly miniaturized devices intended to switch, modulate, filter or tune electrical signals from DC to microwave frequencies. The micromachining techniques used to fabricate these components are based on the standard clean-room manufacturing processes for high-volume integrated semiconductor circuits. RF~MEMS switches are characterized by their high isolation, low insertion loss, large bandwidth and by their unparalleled signal linearity. They are relatively simple to control, are very small and have almost zero power consumption. Despite these benefits, RF~MEMS switches are not yet seen in commercial products because of reliability issues, limits in signal power handling and questions in packaging and integration. Also, the actuation voltages are typically too high for electronics applications and require additional drive circuitry. This thesis presents a novel MEMS switch concept based on an S-shaped film actuator, which consists of a thin and flexible membrane rolling between a top and a bottom electrode. The special design makes it possible to have high RF isolation due to the large contact distance in the off-state, while maintaining low operation voltages due to the zipper-like movement of the electrostatic dual-actuator. The switch comprises two separately fabricated parts which allows simple integration even with RF circuits incompatible with certain MEMS fabrication processes. The two parts are assembled by chip or wafer bonding which results in an encapsulated, ready-to-dice package. The thesis discusses the concept of the switch and reports on the successful fabrication and evaluation of prototype devices. Furthermore, this thesis presents research results in wafer-level packaging of (RF) MEMS devices by full-wafer bonding with an adhesive intermediate layer, which is structured before bonding to create defined cavities for housing MEMS devices. This technique has the advantage of simple, robust and low temperature fabrication, and is highly tolerant to surface non-uniformities and particles in the bonding interface. It allows cavities with a height of up to many tens of micrometers to be created directly in the bonding interface. In contrast to conventional wafer-level packaging methods with individual chip-capping, the encapsulation is done using a single wafer-bonding step. The thesis investigates the process parameters for patterned adhesive wafer bonding with benzocyclobutene, describes the fabrication of glass lid packages based on this technique, and introduces a method to create through-wafer electrical interconnections in glass substrates by a two-step etch technique, involving powder-blasting and chemical etching. Also, it discusses a technique of improving the hermetic properties of adhesive bonded structures by additional passivation layers. Finally, it presents a method to substantially improve the bond strength of patterned adhesive bonding by using the solid/liquid phase combination of a patterned polymer layer with a contact-printed thin adhesive film. / QC 20100617