Research On Wiring Technology Of Patterned Metal On The Surface Of PET Substrates

Based on flexible electronic technology,wearable electronics have drawn increasing interest in recent decades.The unique flexibility and malleability of flexible electronics make them possible to be bended and deformed.The adaptive and easy-fitting flexible electronics can be widely applied in the area of wearable electronics.Polyethylene terephthalate(PET)is one of the most ideal substrates to be used in the fabrication of flexible electronics because of its well mechanical properties,stable chemical properties of the surface,good bending endurance and low cost.Large demands in consuming market have bring massive opportunities and challenges to the development of flexible electronic technology.When used as flexible substrates,PET usually face problems like difficulty in surface metalizing and poor adhesion between metal layer and substrate.It is a key point in the area of flexible electronics research to find a low-cost and efficient way to fabricate high-quality metal circuits on flexible substrates.The thesis has used inkjet printing to plant patterned catalytic layer on surface modified PET substrates.Afterwards,electroless deposition has been introduced to fabricate patterned metal wires on PET substrates.Research is as follow.(1)Functional groups including amino and mercapto groups which can tightly bond with metals have been successfully self-assembled on PET substrates by using ions adsorption solution with APTES and MPTES.Roughness on substrate surface has been enlarged,which can provide mechanical bonding points for copper to bond with and can enhance the adhesion between copper layer and substrates.(2)The thesis has planted a patterned layer of silver ions catalytic ink on modified PET substrates through inkjet printing.After being compared and tested,it turns out that the silver ions layer has good adhesion with modified substrates.Adsorption center for copper to deposit subsequently has been shaped,leading to a copper layer with better adhesion.(3)To fabricate high-quality copper patterns on patterned PET substrates,electroless deposition has been introduced.After being characterized by SEM,EDS,XRD,four point probe,et al.,it proves that copper layer fabricated by the process is in compact morphology,relatively high purity and crystallinity,excellent conductivity(81.44% of bulk copper),good accuracy in inkjet printing with a line width of 89 ?m and outstanding adhesion which reaches the highest level(5B)of the ASTM D3359-02 standard.The flexibility of copper layer can stay reliable in electrical and mechanical properties even after 1000 times of bending in different radii.These results above imply that the simply and highly reliable wiring technology can fabricate patterned copper layer with superior electrical and mechanical properties in a low-cost and highly efficient way,which makes it very promising to be applied to manufacture flexible electronics.