Component Atta hment in Lithographi Film Cir uits

P. S. A. Evans, P. M. Harrey, B. J. Ramsey & D. J. Harrison Abstra t Condu tive Lithographi Films are an emerging fabri ation pro ess for ele troni ir uits and systems. This paper reviews the manufa ture and properties of CLF ondu tors, and des ribes a series of experiments to hara terise bonds formed between them and surfa e-mount-te hnology (SMT) omponent pa kages employing ele tri ally ondu tive adhesives. The purpose of this work is to dire tly ompare the hara teristi s of solder joints between SMT pa kages on s reenprinted alumina substrates, and ondu tive adhesive bonds formed between similar omponents and CLF substrates. The prin ipal failure me hanisms of lmadhesive bonds in shear on various polymer substrate materials are identi ed and statisti al data on bond strengths presented. Indexing Terms:Cir uit Boards, Thi k Film Ciruits, Condu tive Inks and Adhesives, Printed Films, O set Lithography, Mi rowave Stru tures, Printed Inter onne t, Bond Strength, Redu ed Environmental Impa t. 1 Introdu tion:Condu tive Lithographi Films (CLF) [1℄, are an emerging fabri ation te hnique for a wide range of ele troni ir uits and systems. The pro ess employs standard o set lithographi printing to produ e ele tri ally ondu tive lm patterns on a range of exible substrates using a purpose-developed ondu tive ink. CLF substrates an be printed rapidly, via a one-stage printing pro ess, and are onsequently heap to produ e. The lms are robust, withstanding a range of standard ir uit board test regimes, and present few environmental hazards in disposal. 2 The Lithographi Printing Pro ess. O set Lithography ( gure 1) is the te hnology used to mass produ e books and magazines. It relies on the a tion of two dissimilar wetting fun tions on the surfa e of a smooth and un-embossed printing plate. Conta t with ink and moistening rollers allows the printing plate to attra t both water and ink. The plate hemistry repels water where an image is required, allowing an oil-based ink to adhere. A water lm repels the ink in other regions of the plate. Blanket Cylinder Impression Cylinder Printing Plate Cylinder Moistening Roller Ink Rollers