Fabrication And Characterization Of High-resolution Silver Patterns On Polyimide Films

As a core component of electronic device interconnection,silver patterns are widely used in flexible printed circuit boards(FPCs),RFID tags and largearea sensors,etc.At present,the preparation of silver patterns still relies on photolithography technology,which is very complicated and relies on photoresist templates,manifested as heavily polluted and costly.Therefore,the purpose of this paper is to explore a new method for preparing silver patterns,using inkjet printing technology to prepare silver patterns with high definition resolution,high conductivity and strong interfacial adhesion on flexible polyimide films,while maximizing the retention of silver patterns Matrix properties.Here,based on the ionic self-metallization method for preparing silver layers,two methods for preparing silver patterns,surface modification in-situ metallization method and in-situ selective ion exchange method,have been innovatively proposed.The surface-modified in-situ metallization method utilizes an alkaline glue solution with controllable rheology to construct a patterned ion-exchange modified layer on the surface of the films.The mechanism was investigated by Fourier transform infrared spectroscopy(ATRFTIR);the morphology and aggregation of silver particles during the preparation process were studied by scanning electron microscopy(SEM)and atomic force microscopy(AFM).The relationship between etchant concentration,etching time,type of ion-exchange fluid,exchange time and film conductivity was studied by inductively coupled plasma mass spectrometer(ICP)and four-probe test;any shape with line width above 0.2 mm was edited The silver patterns were finally successfully fabricated,with sheet resistance as low as 1 Ω/sq and interfacial adhesion reaching ISO class 0.The in situ selective ion exchange method directly utilizes polyamic acid for patterned in situ ion exchange.The formation mechanism of silver particles in the patterning process was studied by X-ray diffraction(XRD),SEM,X-ray photoelectron spectroscopy(XPS)and other tests.At the same time,it was found that there were differences in the effect of silver metallization on different substrate surfaces.Combining chemical reduction and thermal cyclization,the process time can be effectively shortened;The silver patterns of any shape with a final line width of about 0.5 mm were successfully prepared,with sheet resistance less than 2ω/sq and the tensile strength of about 100 MPa.