Fabrication of Polymer Silver Conductor Using Inkjet Printing and Low Temperature Sintering Process

In this paper, silver powders with a uniform particle size of 0.2-0.4 mu m and an excellent dispersibility were applied to produce a conductive ink for the inkjet printing process. The thermal behaviors of silver particles sintered at different temperature were investigated through X-ray diffraction (XRD) patterns. It was found out that both the particle size and crystal grains increase during the surface diffusion and sintering process. A drop-on-demand (DOD) inkjet printing system was employed to print the conductor by using as-mentioned silver particles suspended in terpineol/polyketone (PK) system as conductive materials. The optimized value of W-PK/W-silver was 5%, corresponding to a resistivity of 2.0 mu Omega.cm. It was revealed that an increase in the W-PK/W-silver ratio resulted in the increase in both the resisitivity and adhesion strength of the conductor. The scanning electron microscopy (SEM) analysis based on the microstructures of silver conductor further illustrates that the densitication of conductor and long-range interparticle connectivity ensure the silver conductor a low resistivity. The adhesiveness effect from PK resin enables the conductor a high adhesion strength.