The future of printed electronics involves advancements not only related to full system integration,but also lean process manufacturing.A critical aspect of this progress is developed in this study,which evaluates a h...The future of printed electronics involves advancements not only related to full system integration,but also lean process manufacturing.A critical aspect of this progress is developed in this study,which evaluates a highly flexible screen printed through-hole-via using silver microparticle inks,for applications in energy harvesting and storage modules.The printed vias’fabrication and durability are evaluated by means of a double sided screen-printing method and repetitive(cyclic)bending tests.Vias,through 125-µm-thick PET foil,were laser cut(nominally 50,100,150,and 200µm diameters)then filled,and simultaneously connected to adjacent vias by screen printing.To investigate the use of the printed via in a monolithic energy module,the vias were used for the fabrication of a flexible printed supercapacitor containing aqueous electrolyte and carbon electrodes.The results indicate that the lower viscosity silver ink(DuPont 5064H)fills the via less effectively than the higher viscosity ink(Asahi LS411AW),and as the via size increases(≥150µm diameter)via walls are coated rather than filled.Conversely,the more viscous ink fills the via thoroughly and exhibited a 100%yield(1010 vias;100µm nominal via diameter)with the two-step direct screen-printing method.The 10-mm radius bending test showed no signs of via specific breakdown after 30,000 cycles.The results indicate that this via filling process is likely roll-to-roll compatible to enable multi-layered printed electronic devices.展开更多
Interposers with through-silicon vias(TSVs)play a key role in the three-dimensional integration and packaging of integrated circuits and microelectromechanical systems.In the current practice of fabricating interposer...Interposers with through-silicon vias(TSVs)play a key role in the three-dimensional integration and packaging of integrated circuits and microelectromechanical systems.In the current practice of fabricating interposers,solder balls are placed next to the vias;however,this approach requires a large foot print for the input/output(I/O)connections.Therefore,in this study,we investigate the possibility of placing the solder balls directly on top of the vias,thereby enabling a smaller pitch between the solder balls and an increased density of the I/O connections.To reach this goal,inkjet printing(that is,piezo and super inkjet)was used to successfully fill and planarize hollow metal TSVs with a dielectric polymer.The under bump metallization(UBM)pads were also successfully printed with inkjet technology on top of the polymer-filled vias,using either Ag or Au inks.The reliability of the TSV interposers was investigated by a temperature cycling stress test(−40℃ to+125℃).The stress test showed no impact on DC resistance of the TSVs;however,shrinkage and delamination of the polymer was observed,along with some micro-cracks in the UBM pads.For proof of concept,SnAgCu-based solder balls were jetted on the UBM pads.展开更多
基金This work was partially funded by Business Finland as a part of the Towards Digital Paradise project(decision no.2742/31/2016)T.M.K.was supported by a postdoctoral research fellowship received from the Tampere University of Technology Foundation(2016-2018)M.M.is supported by the Academy of Finland(grant nos.288945 and 319408).
文摘The future of printed electronics involves advancements not only related to full system integration,but also lean process manufacturing.A critical aspect of this progress is developed in this study,which evaluates a highly flexible screen printed through-hole-via using silver microparticle inks,for applications in energy harvesting and storage modules.The printed vias’fabrication and durability are evaluated by means of a double sided screen-printing method and repetitive(cyclic)bending tests.Vias,through 125-µm-thick PET foil,were laser cut(nominally 50,100,150,and 200µm diameters)then filled,and simultaneously connected to adjacent vias by screen printing.To investigate the use of the printed via in a monolithic energy module,the vias were used for the fabrication of a flexible printed supercapacitor containing aqueous electrolyte and carbon electrodes.The results indicate that the lower viscosity silver ink(DuPont 5064H)fills the via less effectively than the higher viscosity ink(Asahi LS411AW),and as the via size increases(≥150µm diameter)via walls are coated rather than filled.Conversely,the more viscous ink fills the via thoroughly and exhibited a 100%yield(1010 vias;100µm nominal via diameter)with the two-step direct screen-printing method.The 10-mm radius bending test showed no signs of via specific breakdown after 30,000 cycles.The results indicate that this via filling process is likely roll-to-roll compatible to enable multi-layered printed electronic devices.
基金This work is supported by ENIAC-JU Project Prominent Grant No 324189 and Tekes Grant No.40336/12 and Vinnova Grants Nos.2012-04301,2012-04287,and 2012-04314MM is supported by the Academy of Finland Grant Nos.288945 and 294119The work of Silex and KTH was funded in part through an Industrial Ph.D.grant from the Swedish Foundation for Strategic Research(SSF),Grant No.ID14-0033.
文摘Interposers with through-silicon vias(TSVs)play a key role in the three-dimensional integration and packaging of integrated circuits and microelectromechanical systems.In the current practice of fabricating interposers,solder balls are placed next to the vias;however,this approach requires a large foot print for the input/output(I/O)connections.Therefore,in this study,we investigate the possibility of placing the solder balls directly on top of the vias,thereby enabling a smaller pitch between the solder balls and an increased density of the I/O connections.To reach this goal,inkjet printing(that is,piezo and super inkjet)was used to successfully fill and planarize hollow metal TSVs with a dielectric polymer.The under bump metallization(UBM)pads were also successfully printed with inkjet technology on top of the polymer-filled vias,using either Ag or Au inks.The reliability of the TSV interposers was investigated by a temperature cycling stress test(−40℃ to+125℃).The stress test showed no impact on DC resistance of the TSVs;however,shrinkage and delamination of the polymer was observed,along with some micro-cracks in the UBM pads.For proof of concept,SnAgCu-based solder balls were jetted on the UBM pads.
