Heterogeneous integration of autonomous smart films based on electrochromic transistors

Transcription

1 of autonomous smart films NEWSLETTER #4

2 Objectives SMART- is today at M36; it aims at the development of self-powered electrochromic () thin film transistor matrix device with improved speed and lifetime for multifunctional applications as automotive, ID-cards and smart packaging. The simplified common device to be integrated in final demonstrators is shown below. SMART- Electrochromic TFT SMART- integrated battery Standard integrated PV Gate Anode Cathode TFB Electrolyte Cathode Electrolyte Absorbing layers Electrodes Anode TFB Drain Source TCO 8x8 inorganic electrochromic active matrix integrating electrochemical (electrochromic) transistors Major achievements Full integration of functionalities and geometries for both co-integrated and convergence architectures for all demonstrators. Example of automotive demo. Printed 8x8 inorganic electrocromic passive matrix Subsystems assembling and backplane foil patterning Latest events Autumn School 2012 Printed Electronics and Foil Assembly Fraunhofer EMFT, Munich 19th-20th November 2012 M24 Review Meeting Fraunhofer EMFT,Munich 29th 30th April 2012 M30 Technical meeting CEA, Grenoble 18th 19th July 2012

3 Technical Achievements SP1- Systems design and requirements The SP1 main objective was the circuitry design of each demonstrator based on selected subsystem devices. The strategy adopted to fulfill this task was divided in two steps: - System design methodology development using SMART- or similar available sub-components connected with the best efficiency possible using the best ICs available. - Design development strictly combined with integration strategies based on flexible backplane suitable for integration using drilling vias of display, battery, PV cell, circuit (with communication system and power management) and thin IC sub-components The different SMART- phases to produce the design include: - design of building blocks - selection of the ICs components - design of backplane electrical interconnections The backplane will contain only the circuitry for the interconnection phase to attach: - flexible display (8x8 matrix and SMART- logo) - flexible polymer or TFB - flexible or glass PV cells - thin IC component Circuit and communication films will be fabricated depending on the demonstrator requirements and can be in the same foil and can contain discrete not flexible passive components with small shape in order to guarantee the overall maximum flexibility of the system. A fundamental step in the design phase was to tune electrical circuitry with building blocks dimensions considering the available assembling strategy. After considering the demonstrators requirements related to automotive reconfigurable switch, information availability for ID-cards and packaging label, BioAge provided a full design of functionalities and geometries for both co-integrated and convergence architectures. An example of automotive layout is shown in figure.

4 SP2 SP2 - D e p o s i t i o n t e c h n o l o g i e s The SP2 scope is the optimization of deposition technologies of materials for their integration in the building blocks. The SP2 objectives of the second year of project was the identification of the critical process parameters and the identification of the interaction between processes and materials. The work developed since month 24 was focused on the final selection of materials and process flow regarding the production of the subsystems to be integrated on the different demonstrators. Two types of batteries have been developed: polymer ones (produced using wet coating) and thin film battery(produced by PVD). The materials selection was already presented in previous newsletters. Materials development and process control concerning the energy sub-system were related mainly to the PVD techniques for V 2 O 5, lithiumandliponaswellasthewetdepositionof electrodes and polymer electrolyte and battery assembling. The work during this period was focused on the identification of the risks on materials integration/compatibility and processes. Electrochromic passive matrix + Polymer battery Thin film battery Ti encapsulation Encapsulation Lithium anode LiPON electrolyte V 2O 5 cathode Ti collectors Kapton substrate Aluminium encapsulation The electrochromic () displays to be integrated in the demonstrators are being produced by screen printing. The focus during the last months was on the integration requirements, namely positioning of contact pads. Via holes (laser cut) filled with silver paste are required. _ Sub-system Material Deposition technique Most critical parameter Electrochromic display Batteries Inkjet Precursor stability and ink wettability WO 3 Screen printing Precursor stability and its compatibility with the thickener (proper viscosity) Electrochemical Electrical field/potential and dispersant agent/particle size for EPD Composite electrolyte Casting/Screen printing Shrinkage (when cured) and adhesion to the substrate V 2 O 5 PVD Cooling steps during deposition LiPON PVD Deposition pressure and nitrogen flow Lithium PVD Atmosphere and lithium heating ramp BEMA electrolyte Casting UV curing Electrodes Casting Solvent evaporation and heat treatment Electrodes/electrolyte Casting Assembly in dry environment

5 SP3 Building Blocks The SP3 is devoted to the development of building blocks to be integrated in the final multifunctional system. The specific objectives within this work are related to : - electrochemical (electrochromic) thin film transistors (TFT) for future integration in display, - flexible energy harvesting module (automotive and packaging), - RF antenna coupled with IC for wireless communication. The developments made on the materials integration and identification of critical process parameters done at SP2 has been transferred to SP3 in order to produce the different building blocks. Passive electrochromic 8x8 passive matrix displays using printed WO3 were developed at UNINOVA. Besides and making using of the electrolyte gated transistors, the first active matrices are demonstrated at M36 using PVD deposition. Both GIZO and WO3 are being used as semiconductor material in the transistors. The last were developed along the project and result in a device where the channel change color. The development of printed active matrix displays is undergoing. Concerning energy harvesting module, the battery building blocks produced at POLITO and CEA are ready and being transferred to SP4. Before integrations they are tested to determine if they fit the specifications. G24i is proposing a specific configuration to full fill power requirements within the project. In a first prototypes of those DSSC modules suitable for demonstrators, cells are interconnected in series allowing to obtain the voltage required for the application. In order to test the principle of the backplane technology and to verify design simulations for wireless communication, a prototype antenna was successfully fabricated at ACREO.

6 SP4 The objective of the SP4 is the integration of the building blocks optimized in SP3 by heterogeneous integration involving dry, wet processes and lamination steps. To achieve a stand-alone operating system, the display has to be electrically and mechanically combined with the energy storage device, the energy harvesting and sensors/communication subsystems. At Fraunhofer EMFT experiments are undergoing to assemble the building blocks developed by the different partners on the flexible backplane being processed in a roll to roll approach. In the image is shown a flexible PV cell and foil thin film batteries (TFB) on a tiled kapton/copper foil. In order to align the subsystems to the backplane in automatic pick and place assembly a set of alignment marks is needed on each subsystem and correspondingly in the backplane metallisation. The image shows alignment marks for an interposer for a packaged chip. Battery Improved convergence architecture TFB UNINOVA and CEA are jointly responsible for producing a +TFB subsystem in convergence architecture. In order to reach the final convergence architecture an initial structure was developed by CEA. However this resulted in a non optimized building blocks. Is now under being produced a second architecture that makes use of less common layers, although able to result in optimized building blocks.

7 SP5 SP5 D e m o n s t r a t o r s i n t e g r a t i o n The SP5 objective is the development of prototypes and demonstrators based on the knowledge on design, deposition and integration processes developed in SP2, SP3 and SP4. The high degree of multifunctionality of the novel self-powered flex devices is a key factor for a potential application in several sectors in which the flexible electronics is expected to bring a real breakthrough with a great economic and social impact. To prove this multifunctionality, within SMART-, the following applications will be developed: Autonomous systems for automotive, Multifunctional flexible foils for ID-cards and Multifunctional flexible foils for smart packaging. The first demonstrators are being assembled using the different building blocks in order to validate them and the backplane architecture. Beside display and energy harvesting blocks also the communication one and the microcontroller are being integrated in the demonstrators. The automotive demos will integrate a-si solar cells as power supply having also auxiliary battery. Automotive demo The ID card demo does not have a battery, makinguseofarfantenna topowertheentire system. ID carddemo Smart packaging demo integrates both battery and flexible solar cells. display is common to all demonstrators. Smart packaging demo

8 Latest Events AUTUMN SCHOOL Autumn Workshop Fraunhofer EMFT, Munich 19th-20th November 2012 Cross interaction initiated by COSMIC project between 4 EU projects (COSMIC, POLARIC, Interflex, SMART-). SMART- consortium was represented by partners Politecnico di Torino presenting materials for and batteries, EMFT presenting assembling and foil packaging technologies, UNINOVA showing novel results of thin film technology and CEA on novel harvesting and storage systems. PROJT MEETINGS Fraunhofer EMFT (Munich) M24 Review meeting 30th October th The mid term meeting at M24 was held in Munich (Germany) in October 2012 at Fraunhofer EMFT. During the meeting the final outputs of SP1 were presented and approved together with advancements in SP2, SP3 and SP4. M30 Technical meeting CEA (Grenoble) 18th 19th July 2012 The M30 technical meeting was held in Grenoble (France) in July 2013 a CEA. The meeting was particularly important to check the status of the achievements in terms of materials selection and technologies for building block production and integration according to the recommendation received from the PO after the review meeting. Upcoming Events PROJT MEETINGS M36 Review meeting European Commission (Brussels) 25th November 2013 The next review meeting at M36 will be held in Brussels (Belgium) in November SYMPOSIUM AND WORKSHOP EMRS 2014 Spring Meeting Lille (France) May 26th-30th Symposium R Towards flexible ion based devices Partners UNINOVA, AVREO, CEA, POLITO and CRF will organize another symposium, this time at the prestigious ERMS Spring Meeting. The aim to promote discussion among the international scientific community dealing with this topic. Apart form that, a workshop will be also organized in order to promote the achievements of SMART-.

9 CONSORTIUM Contact Vito Lambertini Group Materials Labs Centro Ricerche Fiat S.C.p.A. Strada Torino Orbassano (TO), Italia Tel