Fabrication of micron scale metallic structures on photo paper substrates by low temperature photolithography for device applications

Abstract

Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Using commercial standard paper as a substrate has a significant cost reduction implication over other more expensive substrate materials by approximately a factor of 100 [1][2]. Discussed here is a novel process which allows photolithography and etching of simple metal films deposited on paper substrates, but requires no additional facilities to achieve it. This allows a significant reduction in feature size down to the micron scale over devices made using more conventional printing solutions which are of the order of tens of microns. The technique has great potential for making cheap disposable devices with additional functionality, which could include flexibility and foldability, simple disposability, porosity and low weight requirements. The potential for commercial applications and scale up is also discussed. Keywords: Paper, Flexible, Photolithography, Microelectronics IntroductionSilicon has long been the industrial standard substrate for devices made using photolithographic processing. It is only in recent years that more flexible substrates have become commercially interesting [3][4]. This is partially due to their potential to be used within the printing industry, as well as the possibility of developing flexible devices. Typical flexible films tend to be polymer based and have specialist coatings on the surface to allow the material to remain stable when being subjected to temperature and humidity changes [5][6].To date, electronics work on paper substrates has tended to be limited to using a variety of printing techniques [7][8]. While these are ideal for roll to roll processes [9], there is a limitation on feature size which is achievable using printing; this limit is 20-40 microns [10]. Similarly a significant amount of device fabrication on paper tends to use a barrier layer on the surface to ensure the printed inks do not permeate into the cellulose matrix of the material [11].There are many different types of papers available, each with their own unique properties [1,2,12]. Some of these can be found to be more suited to metal deposition than others. To date though, most electronics applications on paper use printing [13][14], with a few using a shadow mask technique or stencil [15][16].Electrical measurements show that the conductivity of a feature on paper, when compared to the same feature on silicon, can vary depending on paper type as well as by the deposition technique, for both thin film and ink-jet printed devices 2 can vary depending on paper type as ...

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Fully Inkjet‐Printed Thin‐Film Transistor Array Manufactured on Paper Substrate for Cheap Electronic Applications

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