Integrated capacitors for conductive lithographic film circuits

This paper reports on fabrication of low-value embedded capacitors in conductive lithographic film (CLF) circuit boards. The CLF process is a low-cost and high speed manufacturing technique for flexible circuits and systems. We report on the construction and electrical characteristics of CLF capacitor structures printed onto flexible substrates. These components comprise a single polyester dielectric layer, which separates the printed electrode films. Multilayer circuit boards with printed components and interconnect can be fabricated using this technique

Testing of mixed-signal systems using dynamic stimuli

The impulse response of a linear circuit element contains enough information to functionally characterise that element. A technique for comparison of observed and expected (reference) transient responses, which results in an absolute measure of device functionality, is presented. Comparisons of transient response test results with the results from existing test programs are also presented

Conductive lithographic films

This paper reports progress in the development of a novel fabrication technique for printing circuit board designs directly onto suitable substrates. Circuit tracks can be formed on organic or synthetic substrates by depositing films of a metal-loaded ink via a standard lithographic printing process. The application of this work is in substitutes for conventional (copper-clad resin/laminate) circuit boards where, for low complexity circuits, directly printed substrates offer cost advantages and environmental benefits. The paper is a resume of work and results, including; ink formulation, environmental test, circuit modelling and life cycle analysis. Conductive lithographic films have now been successfully demonstrated in a telephone handset developed in conjunction with Nortel, microprocessor and microwave stripline applications. Whilst developed primarily as a low cost, low environmental impact alternative to subtractive PCB manufacture, other potential advantages such as flexibility and environmental robustness are apparent

Lithographically printed voltaic cells - A feasibility study

It has been shown that circuit interconnects and various passive components can be fabricated on a variety of flexible substrates using the offset lithographic process. This paper reports on a feasibility study investigating the manufacture of voltaic cells deposited via offset lithography

Development and characterisation of lithographically printed voltaic cells

This paper reports progress in the fabrication of voltaic cells and batteries via offset lithographic printing. Successful design and manufacture of lithographically printed voltaic cells would facilitate the integration of printed passive components, interconnects and display elements for disposable electronics in low-volume, low weight circuits and systems. The conductive lithographic film (CLF) printing process was developed by Brunel University to fabricate circuit interconnect and various passive components at high speed and low cost. A feasibility study, investigating printed cells based on zinc-carbon electrochemistry, is described. This has resulted in the production of a printed battery able to power a microcontroller-driven LED display system for more than three hours. Further work seeks to improve cell capacity, address manufacturing process issues, and characterise the structures in more detail

Lithographic technology for microwave integrated circuits

Conductive lithographic films (CLFs) have been developed primarily as substitutes for resin/laminate boards, which share properties with the metallisation patterns used in planar microwave integrated circuits (MICs). The authors examine the microwave properties of the films and show that, although the losses are greater, they have potential as an alternative to the traditional manufacturing process of MICs

Electroluminescent light sources via soft lithography

Purpose: Microcontact printing is a process used to print high resolution protein arrays for biosensors. We investigate using these techniques to print electrically conductive fine line structures for electroluminescent (E/L) light sources. Approach: The viability of using microcontact printing as a process for electronics fabrication is investigated. Polydimethylsiloxane (PDMS) stamps inked with alkanethiol compounds form Self Assembled Monolayers (SAM) on substrate surfaces, acting as the resist to subsequent etching processes. The printed lines are characterized with regard to their performance as high electric field generators in electroluminescent displays. Findings: It has been demonstrated that microcontact printing is a cheap, repeatable process for fabricating electronic devices. The results demonstrate the viability of the process to fabricate electric field generator structures for E/L light sources with reduced driving voltages. Value: It has been demonstrated that microcontact printing can produce electrically conductive fine-line structures with high resolution, confirming its viability in printed electronics manufacture

A time-strain monitoring system fabricated via offset lithographic printing

This paper reports progress in the development of strain sensors fabricated using the Conductive Lithographic Film (CLF) printing process. Strain sensitive structures printed via an unmodified offset lithographic printing press using a silver loaded conductive ink have been deposited concurrently with circuit interconnect, to form an electronic smart packaging system. A system populated with SMT components has proven successful in interpreting and logging deformation incidences subjected to a package during testing. It is proposed that with further development such a system could be printed in sync with packaging graphics using a single printing process to form an integrated time – strain monitoring system

Characterization of lithographically printed resistive strain gauges

This paper reports progress in sensor fabrication by the conductive lithographic film (CLF) printing process. Work describing strain-sensitive structures manufactured using a modified printing process and conductive inks is addressed. The performance of a "single-ink" strain-sensitive structure when printed on six alternative substrates (GlossArt, PolyArt, Teslin, Mylar C, Melinex, and Kapton) is analyzed. Though not intending to compete with conventional gauges in high-tolerance measurement, the structures exhibit properties that indicate suitability for novel applications

Test structures to characterise a novel circuit fabrication technique that uses offset lithography

This paper reports on the use of microelectronic test structures to characterise a novel fabrication technique for thin-film electronic circuit boards. In this technology, circuit tracks are formed on paper-like substrates by depositing films of a metal-loaded ink via a standard lithographic printing process. Sheet resistance and line width are electrically evaluated and these quantities are compared with optical and surface profiling measurements