Development of an Adhesive-Dispensing-Unit for precision application purposes in the production of wafer scale micro-optical components

TCC(graduação) - Universidade Federal de Santa Catarina. Centro Tecnológico. Engenharia de Controle e Automação.A crescente demanda por produtos ópticos pequenos e precisos para sistemas ópticos miniaturizados em várias aplicações exigentes necessitam de uma tecnologia de produção adequada para esses componentes feitos de vidros especializados. Enquanto as tecnologias de ponta utilizam um processo de retificação, polimento ou de corrosão demorada e cara, o inovador projeto de pesquisa Wafer Level Optics (WLO) se foca em uma abordagem baseada em placas via modelagem precisa em vidros. Essa abordagem promete um meio efetivo de aproveitar um efeito de escala adequado, levando a duas grandes vantagens: primeiramente, a produção em nível de placas permite uma produção menos custosa de centenas de elementos ópticos em apenas um passo de produção. Segundo que também facilita outros passos subsequentes, desde, por exemplo, o manuseio e alinhamento dos elementos podem ser feitos em escala de placas também. Ainda que esse método de produção já é uma tecnologia de ponta nas indústrias de litografia e semicondutores e também é usado largamente na produção de componentes ópticos de plástico, sua transferência para a produção de componentes micro-ópticos de vidro ainda apresenta várias dificuldades cruciais ainda não resolvidas e alguns problemas operacionais. Do ponto de vista metrológico, as dificuldades se encontram no alinhamento exato entre as placas. Nesse ponto, o alinhamento por frentes de onda de um sistema óptico promete ser altamente adequado para o alinhamento de uma placa inteira com a precisão necessária no nível de sub-um. A grande necessidade para pequenas tolerâncias é devido aos efeitos, que até as pequenas imperfeições no processo de alinhamento têm na função óptica do sistema. Entretanto, a precisão e a função óptica de um sistema micro-óptico não é apenas dependente da precisão do alinhamento, mas também da capacidade de colar as placas alinhadas entre si com grande precisão e numa determinada posição Para atingir um bom resultado na união é de grande importância ajustar as propriedades do adesivo para o processo de união escolhido. Na cadeia desse processo rigoroso, o projeto Wafer Level Optics considera que a união das placas alinhadas precisa der considerado simultaneamente com o procedimento de alinhamento propriamente dito. Para atingir um resultado ótimo de união, as propriedades físicas do adesivo precisam ser combinadas com o processo de colagem e dos requisitos dependentes. Portanto a escolha de um adesivo adequado está fortemente ligado com o projeto do aparelho de alinhamento, já que o método de secagem do adesivo é altamente influenciado pelo procedimento de alinhamento. Depois do adesivo ser avaliado fisicamente, a segunda maior tarefa envolve o processo de aplicação e o desenvolvimento de um dispositivo adequado. O adesivo será aplicado externamente através de um sistema de tecnologia de microgotas, permitindo gotas bem pequenas no nível de 20pl com uma frequência máxima de 6kHz. Essas características são usadas para projetar um processo de aplicação dinâmico, em que a placa é movida em uma mesa xy em altas velocidades sob o sistema de despejamento. O processo de aplicação tem o objetivo de realizar um procedimento automatizado, no qual a placa colocada no sistema receberá a quantidade exata de adesivo nas posições exatas entre os elementos micro-ópticos. Por isso, séria necessário projetar, criar e montar um aparelho integrado, capaz de conter o bico e o sistema de aplicação de micro gotas e mover a placa nas direções necessárias. Isso também inclui a escolha e integração de um outro equipamento, como a mesa xy. Para o propósito de automação, será também necessário desenvolver um programa em Lab- View, para controlar e monitorar o processo de aplicação. A placa contendo as gotas de cola será posteriormente colocado em um equipamento para alinhamento, onde depois de um processo preciso de alinhamento, o adesivo será secado.The continuously growing demand for small and precise glass optics for miniaturized optical systems in demanding applications require adequate production technologies for such optical components made of specialized glasses. The Wafer Level Optics research project (WLO) aims at the utilization of a waferbased manufacturing approach via precision glass moulding. This approach promises an effective way to harness adequate scale effects, leading to two major advantages: firstly the wafer-based manufacturing enables the by far more cost effective production of hundreds of optical elements in just one manufacturing step. Secondly it would also facilitate subsequent process steps, since e.g. the handling and alignment of the elements can be undertaken on waferlevel as well. From the metrological point of view, the ostensible difficulties lie in the exact alignment of the wafers to one another. At this point the wavefront-based alignment of an optical system promises to be highly suitable for the alignment of an entire wafer with a necessary accuracy in the sub -um range. The imperativeness of the need for such tight tolerances is deducted by the effects, that even slight imperfections in the alignment process have on the optical function of a system. However, the precision and optical function of a micro-optical system is not only dependant on the accuracy of the alignment, but also on the capability to cement the aligned wafer to one another with high accuracy and within in a well determined position. In order to achieve a good bonding result it is critical to adjust the properties of the adhesive to the targeted bonding process. After the adhesives have been physically evaluated the second major task involves the actual application process and the developement of an adequate appliance. It will be necessary to design, construct and assemble an integrated device, capable of holding the micro drop application nozzle / system and moving the wafer on an automated basis. For automation purposes it will be furthermore necessary, to design a accompanying LabView programme, in order to control and monitor the application process

International Workshop on MicroFactories (IWMF 2012): 17th-20th June 2012 Tampere Hall Tampere, Finland

This Workshop provides a forum for researchers and practitioners in industry working on the diverse issues of micro and desktop factories, as well as technologies and processes applicable for micro and desktop factories. Micro and desktop factories decrease the need of factory floor space, and reduce energy consumption and improve material and resource utilization thus strongly supporting the new sustainable manufacturing paradigm. They can be seen also as a proper solution to point-of-need manufacturing of customized and personalized products near the point of need

圧電インパクト駆動を用いた超精密XYステージと微少液滴塗布機構の開発

本論文では、圧電インパクト駆動を用いた2つの精密位置決め機構とその応用について論じている。近年、情報端末機器などに搭載されている様々なデバイス、アクチュエータやセンサ、レーザ、レンズ、電子部品、機械部品等は微小化が進み、その位置決めや組立は非常に困難になっている。たとえば、接着作業では、接着される部品同士が微小であり、このように微小部品のハンドリング、位置決めおよび極微小量の接着剤塗布などが重要となる。従来の技術を用いて、これらの問題を解決しようとすれば、いくつかの装置を組み合わせて利用することになり、精度や機械剛性の低下に繋がり、システムの大型化がさけられない。また、部品の位置決め時や接着時の検査・観察系を組み込むことが、物理的スペースから困難となる場合が多い。これらを解決するためには、従来よりも小型・精密な位置決め機構、塗布機構などが必要となっている。本論文では圧電インパクト駆動に着目し、まず圧電素子にのこぎり波形状の駆動電圧を与えた場合の移動体の移動量について運動方程式を用いて解析を行っている。次にこの結果に基づいてV 溝XY ステージを試作している。ここではV 溝XY ステージの位置決め性能を測定し、X、Y ステージ共に、最小位置決め分解能75nm を有することを確認した。このステージを用いた精密応用実験として、レンズ把持部をステージ上に搭載し、超小型レンズの調芯作業が可能であることを明らかにした。次にニードル式液滴塗布機構について検討を行った。まずこの方法の原理と構成について述べ、塗布量を左右するさまざまな条件を実験的に求めている。そしてこの方法を用いた場合、塗布量の精度に影響するするニードル先端の接触計測法について論じている。ニードルを機械共振機構で微小振動させ、先端部の液滴が対象物に接触した瞬間に機械共振点が変化することを利用して、接触検知を行っている。この振動系モデルによる解析とその特性を実験的に明らかにしている。次に圧電インパクト駆動されたニードルを用いて液体を基板へ転写する微小液滴塗布機構について論じている。ここでは駆動波形を先端突起付き矩形波形とし、得られる加速度の差から移動体の締め付け力を決定し、微小液滴塗布機構を試作した。微小液滴塗布機構の塗布性能を評価し、V 溝XYステージ上に配置することで、微小液滴塗布装置を構成した。ニードル直径、液体粘度を変化させて塗布実験を行い、高粘度導電ペースト（50,000mPas）を直径12μm で塗布することに成功した。本論文は5 章で構成する。各章の概要は以下の通りである。第 1 章「緒論」では、デバイスの小型化に伴う超精密組立作業の重要性について概観する。そして本研究の位置づけと目的を明らかにし、本論文の構成および各章の概要について述べる。第2 章「圧電インパクト駆動によるBlu-ray Disc 用ピックアップレンズの調芯機構」では、最初に圧電インパクト駆動による超精密位置決めの動作原理を説明する。圧電素子の駆動電圧波形に、のこぎり波形を用いた場合の駆動周波数と移動体の移動量の関係について示す。この方式をBlu-ray Disc 用ピックアップレンズの調芯機構に適用し、開発した圧電インパクト駆動式V 溝XY ステージについて説明している。V 溝XY ステージの位置決め性能について計測結果を示し、X、Y ステージそれぞれの最小位置決め分解能を明らかにしている。レンズ把持部をV 溝XY ステージ上に搭載し、レンズ調芯用のV 溝XY ステージ機構を構成している。レンズ把持部搭載後のV 溝XY ステージの位置決め性能、把持によるレンズの傾きについて実験評価し、位置決め分解能85nm、レンズ傾斜角度0.01 度以下の良好な結果を得た。レーザ干渉計（青色、波長405nm）を用いて干渉縞を観察しながらXY ステージを駆動させて実際にレンズ調芯を行い、偏芯のない位置決めに成功していることを述べている。第3 章「ニードル式液滴塗布装置とニードル先端接触検知法」では、まずニードル式液滴塗布装置の液滴塗布原理について述べる。塗布液体はピペット内に充填されており、この中をニードルが貫通し、ニードル先端部に付着した液体が塗布基板上へ転写されて塗布が行われる。ここでは液体粘度、ニードル直径、ニードル先端と塗布対象面との間隔などに関して塗布量との関係を実験的に求めている。この際、ニードルが塗布基板に衝突すればニードルおよび塗布基板の損傷となる。ニードル先端部を塗布基板に接触させることなく、塗布を行う必要がある。そこでニードル先端部に付着した液体の塗布基板上への接触検知方法に着目し、オンマシンで接触検知する方法を提案している。ここではニードルを機械共振機構で微小振動させ、先端部の液滴が対象物に接触した瞬間に機械共振点が変化することを利用して、接触検知を行っている。ニードル直径、液体粘度、塗布基板を変化させて、ニードル先端液滴の塗布基板への接触検知実験を行っている。ニードル直径100μｍを用いてシリコーンオイル粘度100～100,000mPas の高粘度液体を用いて実験を行い、接触時に共振周波数や振幅の変化から、ニードル先端部の液滴が塗布基板への接触した瞬間の検知に成功している。またニードル振動を用いた塗布により、塗布した液滴の直径ばらつきを低減することができたことを記している。第4 章「圧電インパクト駆動による微小液滴塗布機構」では、微小液滴塗布機構に用いる圧電インパクト駆動の動作原理について述べる。まず圧電素子に印加する駆動電圧波形に着目し、先端突起付き矩形波を提案し、従来ののこぎり波形との特性の相違について比較し、得られる加速度成分について説明している。得られた加速度から移動体の締め付け力を決定し、圧電インパクト駆動式微小液滴塗布機構を試作している。試作機に先端突起付き矩形波を入力し、移動性能評価実験を行い、１μm の位置決め分解能が得られている。さらに圧電インパクト駆動されるV 溝XY ステージと組み合わせて微小液滴塗布装置を構成した。ニードル直径と液体粘度を変化させて、塗布実験を行っている。本試作機を用いて高粘度導電ペースト（50,000mPas）を直径12μｍで塗布することに成功しており、このことにより低抵抗パターン等で重要視されている高粘度液体の微小量塗布が実現し、その実用化が期待できる。また圧電インパクト駆動式微小液滴塗布機構は小型であるため、複数台配置することで高効率な塗布が実現できることが期待される。第5 章「結論と今後の課題」では、本章では本論文をまとめるとともに今後の課題について論じる。緒論では本研究の背景や関連研究を概観するとともに従来の精密位置決め機構の問題点を指摘し、可動範囲の増加、操作性向上、装置の小型化の機能が要求されていることを述べている。次に微小量の液摘塗布技術について、超精密位置決め機構と極細ニードルを用いて液滴を転写する方法について説明し、ニードル先端と塗布面との接触検知の重要性を述べて、既存の接触検知手法について紹介している。また、ニードル式液滴塗布機構では、ニードル駆動ストロークの増加、高分解能位置決め、小型化が要求されていることから、ニードル駆動に圧電インパクト駆動方式を適用することでこれらの要求を満たすことができると考えた。圧電インパクト駆動によるBlu-ray Disc 用ピックアップレンズの調芯機構では、最初に圧電インパクト駆動による超精密位置決めの動作原理について説明している。圧電素子の駆動電圧波形に、のこぎり波形を用いた場合の駆動周波数と移動体の移動量の関係について示し、圧電インパクト駆動式V 溝XY ステージを試作した。レンズ把持部をV 溝XY ステージ上に搭載し、レンズ調芯用のV 溝XY ステージ機構を構成した。V 溝XY ステージ機構は、位置決め分解能85nm、レンズ傾斜角度0.01 度以下の良好な結果を得た。レーザ干渉計（青色、波長405nm）を用いて干渉縞を観察しながらXY ステージを駆動させて実際にレンズ調芯を行い、偏芯のない位置決めに成功した。ニードル式液滴塗布装置のニードル先端位置計測では、ニードル式液滴塗布装置の液滴塗布原理について述べ、ニードル先端部に付着した液体の塗布基板上への接触検知方法を提案した。ニードルを機械共振機構で微小振動させ、先端部の液滴が対象物に接触した瞬間に機械共振点が変化することを利用して、接触検知することができた。ニードル直径100μｍを用いてシリコーンオイル粘度100～100,000mPas の高粘度液体を用いて実験を行い、接触時に共振周波数や振幅の変化から、ニードル先端部の液滴が塗布基板への接触した瞬間の検知に成功している。またニードル振動を用いた塗布により、塗布した液滴の直径ばらつきを低減することができた。圧電インパクト駆動による微小液滴塗布機構では圧電素子の駆動電圧波形について、のこぎり波と先端突起付き矩形波を加速度に着目して比較考察を述べている。試作した2 つの機構について、位置決め性能を明らかにし、実用性について検討している。応用実験では圧電インパクト駆動方式で極細ニードルを高粘度導電性ペースト（50,000mPas）の充填されたピペット内に貫通させて、極微小量（直径12μｍ）の液体の塗布に成功した。電気通信大学201

Manipulation of polymeric fluids through pyro-electro-hydro-dynamics

This thesis is focused on the manipulation of liquids and polymeric fluids in a non-contact and electrode-free way, exploiting pyro-electro-hydro-dynamic systems. The thesis structure provides an introduction based on the theory and the combination between pyroelectric and electro-hydro-dynamic effect, with a focus on the developed techniques, followed by the presentation of the realized works. It will be presented the fabrication of micro-optical devices, in particular micro-lenses, through pyro-electro-hydro-dynamic effect. The attention will be directed toward the fabrication methods: in fact, they have been obtained by an ink-jet technology or through self-assembly on a micro-engineered pyroelectric crystal. In the first case, a new pyro-ink-jet set-up will be proposed and further modifications of the set-up, which will improve the flexibility of the technique, will be reported. The realized micro-lenses will be optically and geometrically characterized and it will be presented the fabrication of a multi-component device as an example of application of this technique. It will be shown that pyro-ink-jet printing permit to realize very uniform micro-lenses arrays with high resolution (diameter ̴ 300 nm). The second approach is based on the self-assembly of a micro-lenses array on a micro-engineered pyroelectric crystal. It will be showed an array decoration by nano-particles, such as quantum dots, and it will be presented the di-electro-phoretic effect on the employed dots. In particular, the study will focus on the effect of the patterned substrate on the localization of the nano-particles and on the investigation of the dots pattern transfer. Moreover, it will be shown another application of pyro-ink-jet printing: the capability of this system in the highly viscous solution manipulation allows the deposition of polymeric fibers and, in particular, how a fiber like these can be used as a component in a microfluidic channel. That demonstrates pyro-ink-jet printer is also an alternative to the classic electro-spinning system, avoiding electrodes and spiraling effect during the deposition. Produced fibers show great uniformity and reach thicknesses until the nano-metric scale. Moreover, there will be illustrated all the procedures realized to produce the micro-channel

Development of a Novel Gradient-Force Tapered Fibre Optical Tweezers System for 3D Optical Trapping at Near Horizontal Fibre Insertion Angles

The use of optical fibre as a mechanism for the delivery of the trapping laser beam to the sample chamber significantly reduces both the size and the build costs of “Optical Tweezers”. Furthermore, the use of fibre facilitates the decoupling of the optical trapping beam from the microscope optics, which provides further scope for the development of a portable optical trapping system, and the potential for uncomplicated integration with other advanced microscopy systems such as an atomic force microscope (AFM) for example. For use with an AFM, the optical fibre must be inserted at an angle of 10° with respect to the sample chamber floor. However, previous literature suggests that 3D optical trapping with a single fibre inserted at an angle ≤20° is not feasible. This thesis presents the design, development, build and test of a single beam optical fibre based gradient force optical tweezers system and its associated software. An investigation is conducted to ascertain why optical trapping, using single fibre systems, cannot be achieved at sub 20° insertion angles, the result of which formed the basis of a hypothesis that explains this limitation. This finding led to the development of tapered optical fibre tips that are cable of 3D optical trapping at an insertion angle of ≤10°. The optimised optical fibre tapers are presented and their ability to trap both organic and inanimate material in 3D at an insertion angle of 10° is demonstrated. The near-horizontal insertion angle introduced a maximum trapping range (MTR). The MTR of the tips is determined empirically, evaluated against simulated data, and found to be tuneable through taper optimisation. Optical trap characterisation has been undertaken in terms of the optical trapping forces acting on the trapping subjects. Finally, the fibre tapering devices ability to reproduce identical tapers, or not, using the same device parameters, was investigated and the results in terms of geometric profile and optical performance are presented

Cumulative index to NASA Tech Briefs, 1963-1967

Cumulative index to NASA survey on technology utilization of aerospace research outpu

Microcantilever biosensors

The cross-sensitivity of microcantilever sensors presents a major obstacle in the development of a commercially viable microcantilever biosensor for point of care testing. This thesis concerns electrothermally actuated bi-material microcantilevers with piezoresistive read out, developed for use as a blood coagulometer. Thermal properties of the sensor environment including the heat capacity and thermal conductivity affect the ‘thermal profile’ onto which the higher frequency mechanical signal is superimposed. In addition, polymer microcantilevers are known to have cross-sensitivity to relative humidity due to moisture absorption in the beam. However it is not known whether any of these cross sensitivities have a significant impact on performance of the sensor during pulsed mode operation or following immersion into liquid. When analysing patient blood samples, any change in signal that is not caused by the change in blood viscosity during clotting could lead to a false result and consequently an incorrect dose of anticoagulants may be taken by the patient. In order to address these issues three aspects of the operation of polymer bi-material strip cantilevers has been researched and investigated: relative humidity; viscosity/density, and thermal conductivity of a liquid environment. The relative humidity was not found to affect the resonant frequency of a microcantilever operated in air, or to affect the ability of the cantilever to measure clot times. However, a decrease in deflection with increasing relative humidity of the SmartStrip microcantilever beams is observed at 1.1 ± 0.4 μm per 1% RH, and is constant with temperature over the range 10 – 37 °C, which is an issue that should be considered in quality control. In this study, the SmartStrip was shown to have viscosity sensitivity of 2 cP within the range 0.7 – 15.2 cP, and it was also shown that the influence of inertial effects is negligible in comparison to the viscosity. To investigate cross-sensitivity to the thermal properties of the environment, the first demonstration of a cantilever designed specifically to observe the thermal background is presented. Characterisation experiments showed that the piezoresistive component of the signal was minimised to -0.8% ± 0.2% of the total signal by repositioning the read out tracks onto the neutral axis of the beam. Characterisations of the signal in a range of silicone oils with different thermal conductivities gave a resolution to thermal conductivity of 0.3 Wm-1K-1 and resulted in a suggestion for design improvements in the sensor: the time taken for the thermal background signal to reach a maximum can be increased by increasing the distance between the heater and sensor, thus lessening the impact of the thermal crosstalk within the cantilever beam. A preliminary investigation into thermal properties of clotting blood plasma showed that the sensor can distinguish the change between fresh and clotted plasma

Jetting of multiple functional materials by additive manufacturing

The rise and consolidation of Additive Manufacturing (AM) as a technology has made possible the fabrication of highly customised and complex products in almost every industry. This not only allows the creation of objects that were impossible just a few decades ago but also facilitates the production of small runs of products at a reasonable cost, which reduces the design-prototyping cycles and boosts product innovation. However, to produce truly functional parts it is desirable for these systems to be able to deposit multiple complex materials in a single process to locally embed controllable properties such as electrical conductivity or sensing capabilities into the produced geometries. Consequently, a review of current AM technologies capable of depositing conductive materials is performed in this PhD and discussed to find the most suitable approaches. Similarly, existing multi-material set-ups are studied to find limitations and common practices to create a system that is capable of fulfilling the objectives of this work. Piezo-activated inkjet printing (PIJ) is identified as an appropriate technology for multi-material applications due to its non-contact nature, high spatial resolution, capability of mixing and digitally grading materials and simple scale-up of the process. Furthermore, in the last decade it has been shown that jetting can be used for the accurate deposition of a wide range of functional materials. However, upon detailed review of this method, the limitations that it imposes on the compositions of the inks are identified as its main drawback. Specifically, the solid content and molecular weight of the fluids that can be jetted are restricted by the viscosity of the final ink, typically under 40 mPa·s. This is problematic in the case of jetting conductive materials, since it forces the solid content to be very low, therefore yielding very thin and often inhomogeneous layers. Additionally, all the organic components on the inks added to facilitate its ejection need to be removed, which typically means longer and more aggressive post-processes before rendering the printed tracks conductive. For this reason, drop-on-demand micro-dispensing valves were chosen as a high viscosity jetting (HVJ) approach in this work, with the intention of assessing their capability as a suitable tool for multi-material AM of functional inks. However, since their resolution and speed are lower than conventional inkjet, a hybrid approach is presented including micro-dispensing valves and inkjet printheads capable of depositing a wide range of viscosities in a single process. A comprehensive description of the hybrid set-up is given, discussing its main elements including the printing heads, the custom design printer assembly, the ultraviolet (UV) and infrared (IR) lamps installed for in-situ processing, the monitoring system and the set-up to measure the evolution of the electrical resistance in printed tracks in real time during post-processing. Additionally, the printing strategy and process flow is discussed. The investigated set-up was used to study the printability and performance of several functional materials ranging from UV-curable polymers to conductive formulations such as carbon paint, a silver nanoparticle-based paste and a dispersion of PEDOT:PSS. Each material was thoroughly characterised prior to printing with a special focus on viscosity. Their drop formation and deposition processes were studied at different printing settings using high speed imaging and footprint analysis of the deposited drops. These tests were used to obtain sets of working parameters that allow reliable printing and were used to produce 2D patterns with different resolutions to find the drop spacing that results in flat homogeneous films. Later, these films were post-treated according to the requirements of each material and multilayer structures were produced and analysed with an optical profilometer. The cross-section of these 3D tracks was used together with the measured resistance to obtain the electric conductivity of the materials under the printing conditions used. Finally, the accumulated information during the previous stages of printing was used to produce 3D multi-material demonstrators with incorporated conductive tracks, electric components and electroluminescent elements. These proof-of-concept samples were used to discuss limitations of the approach and showcase future possibilities of the system